Approved by
the Order of the Federal
Environmental, Industrial
and Nuclear Supervision Service
dated December, 17, 2015 No. 522
FEDERAL RULES AND REGULATIONS
IN THE AREA OF ATOMIC ENERGY USE "GENERAL PROVISIONS
FOR NUCLEAR POWER PLANT SAFETY ASSURANCE"
(NP-001-15)
I. General Provisions
1.1. Purpose and scope of application
1.1.1. These Federal rules and regulations in the area of nuclear energy use “General provisions for nuclear power plant safety assurance" (NP-001-15) (hereinafter referred to as the General Provisions) were developed in accordance with Article 6 of Federal Law N 170-FZ “On Nuclear Energy Use” dated November, 21, 1995 (Collection of Acts of the Russian Federation 1995, N 48, art. 4552; 1997, N 7, art. 808; 2001, N 29, art. 2949; 2002, N 1, art. 2; N 13, art. 1180; 2003, N 46, art. 4436; 2004, N 35, art. 3607; 2006, N 52, art. 5498; 2007, N 7, art. 834; N 49, art. 6079; 2008, N 29, art. 3418; N 30, art. 3616; 2009, N 1, art. 17; N 52, art. 6450; 2011, N 29, art. 4281; N 30, art. 4590, art. 4596; N 45, art. 6333; N 48; art. 6732; N 49, art. 7025; 2012, N 26, art. 3446; 2013, N 27, art. 3451), Decree of the Government of the Russian Federation N 1511 “On approval of the Regulation on development and approval of Federal rules and regulations in the area of nuclear energy use” dated December, 1, 1997 (Collection of Acts of the Russian Federation, 1997, N 49, art. 5600; 1999, N 27, art. 3380; 2000, N 28, art. 2981; 2002, N 4, art. 325; N 44, art. 4392; 2003, N 40, art. 3899; 2005, N 23, art. 2278; 2006, N 50, art. 5346; 2007, N 14, art. 1692; N 46, art. 5583; 2008, N 15, art. 1549; 2012, N 51, art. 7203) and establish safety requirements specific for a nuclear power plant as a source of radiation exposure for the personnel, the public and the environment.
1.1.2. The General Provisions lay down the purposes and the main criteria of nuclear power plant safety as well as the basic principles and general requirements for technical and administrative measures focused on safety assurance. The implementation scope of these principles and measures shall comply with the federal rules and regulations in the area of nuclear energy use. In the absence of necessary regulations, the proposed specific technical solutions are justified in accordance with state of the art in science, technology and production.
1.1.3. These General Provisions shall be applicable to all stages of the complete life cycle of nuclear power plants stipulated by law in the area of nuclear energy use.
1.1.4. The procedure for bringing nuclear power plants into compliance with these General Provisions, including time limits and scope of required activities shall be determined in each particular case under the conditions of siting, construction, operation or decommissioning license.
1.1.5. The list of abbreviations is given in Appendix 1, and terms and definitions are given in Appendix 2 to these General Provisions.
1.2. Main criteria and principles of safety assurance
1.2.1. A NPP complies with the safety requirements if the following conditions are met:
exposure of the personnel, the public and the environment to the NPP radiation under normal operation and normal operation malfunctions (including design basis accidents) does not exceed any established exposure limits for the personnel and the public as well as any release and discharge standards;
exposure of the personnel, the public and the environment to NPP radiation in a beyond design basis accident is limited;
the probability of accidents at the NPP is limited.
1.2.2. The NPP safety is achieved by high-quality design, development and manufacture of the equipment, NPP siting, construction and operation with due regard for the requirements of federal laws, federal rules and regulations in the area of nuclear energy use, by creating and maintaining safety culture, consideration of the operation experience and state-of-the-art science, technology and production.
1.2.3. The acceptable exposure limits for the NPP personnel and the public under normal operation and in case of normal operation malfunctions (including accidents), the acceptable limits for releases of radioactive substances into atmosphere and acceptable limits for discharges of radioactive substances into water bodies are set in accordance with the laws of the Russian Federation.
Levels of exposure resulting from any releases and discharges of radioactive substances from the NPP shall be below the set limits and as low as reasonably achievable.
1.2.4. The NPP safety shall be provided by consistent implementation of defense in depth based on a system of physical barriers in the way of ionizing radiation and radioactive substances into the environment and a system of technical and administrative measures for protection of the barriers and maintenance of their efficiency as well as for protection of the personnel, the public and the environment.
The system of pjysical barriers for the NPP power unit shall include: the boundary of the reactor coolant circuit, the RP containment and biological protection and, as a rule, the fuel matrix and the fuel cladding.
The system of technical and administrative measures shall form five levels of defense in depth and include the following levels.
Level 1. NPP siting conditions and prevention of abnormal operation:
assessment and selection of a site suitable for the NPP location;
arrangement of a sanitary protective area, a supervised area around the NPP as well as a protective action planning zone;
development of the NPP design documentation (hereinafter - the NPP design) based on a conservative approach with well-developed inherent self-protection of the RP and measures aimed at prevention of the cliff edge effect;
assurance of the required quality of the NPP systems (components) and works performed;
operation of the NPP in accordance with the process regulations and production guidelines developed with due regard for the requirements of regulations and other regulatory documents;
maintenance of safety-related systems and components in operable condition by timely detection of defects, implementation of preventive measures, replacement of equipment with exhausted life span, arrangement of an efficient maintenance and repair system, documenting of the operation and monitoring results;
selection and provision of the required qualification level of the NPP personnel for working under normal operation conditions and in abnormal operation including pre-accident situations and accidents, formation of safety culture.
Level 2. Prevention of design basis accidents by normal operation systems:
timely identification of deviations from normal operation and their elimination;
control during operation with deviations.
Level 3. Prevention of beyond design basis accidents by safety systems:
prevention of escalation of initiating events into design basis accidents, and of escalation of design basis accidents into beyond design basis accidents through the use of safety systems;
mitigation of consequences of accidents that could not have been prevented by confinement of the released radioactive substances.
Level 4. Beyond design basis accident management:
return of the NPP to the controlled state in which the fission chain reaction stops and continuous fuel cooling and confinement of radioactive substances within the established boundaries are ensured;
prevention of progression of beyond design basis accidents and mitigation of their consequences, including through the use of special engineering features to manage beyond design basis accidents as well as any systems (components) including normal operation systems (components) and safety systems (components) capable of performing the required functions under the given conditions;
protection of the RP containment from destruction during beyond design basis accidents and maintaining its operability.
Level 5. Emergency planning: preparation and execution of action plans for protection of the personnel and the public at the NPP site and beyond it.
The defense in depth shall be implemented at all stages of activities related to the NPP safety assurance to the extent covered by this type of activity. The adverse events prevention strategy shall take priority, with special attention paid to levels 1 and 2.
All reasonably achievable measures shall be taken to ensure independence of defense-in-depth levels from each other. The applied measures shall be substantiated.
1.2.5. Under normal operation all physical barriers shall be operable and the measures for their protection shall be held in readiness. If it is revealed that any of the designed physical barriers is inoperable or measures for its protection are unavailable, the RP shall be shut down and measures shall be taken to bring the NPP power unit into a safe state. The NPP design shall incorporate measures aimed to prevent damage of any barriers resulting from damage of other barriers as well as damage of several physical barriers under a single impact.
1.2.6. Safe operation limits and conditions shall be substantiated in the NPP design, which shall also incorporate engineering features and administrative measures aimed to prevent any deviations from the safe operation limits and conditions.
1.2.7. Technical and organizational solutions adopted for the NPP safety assurance shall be tried in previous experience, tests, studies and prototype operation practice. This approach shall be applied not only to the equipment development and the NPP design but also to manufacturing of the equipment, the NPP construction and operation, the NPP refurbishment and retrofitting of its systems and components as well as to the NPP decommissioning.
1.2.8. The system of technical and administrative measures for the NPP safety assurance and the design basis for safety-related systems and components shall be stated in the NPP SAR developed by the operating organization in cooperation with the NPP and RP designers. Any safety-related discrepancies between the information contained in the NPP SAR and the NPP design as well as deviations from the NPP design in the course of its implementation are not permitted. The operating organization shall maintain compliance of the NPP SAR with the actual state of the NPP within the entire service life of the NPP.
1.2.9. Deterministic and probabilistic safety analyses shall be presented in the NPP SAR. Safety analyses shall be performed for all operational states of the NPP with due regard for all locations of nuclear materials, radioactive substances and radioactive wastes at the NPP where any anticipated operational occurrence may appear. Deterministic analyses of design basis accidents shall be based on a conservative approach. Probabilistic safety analyses shall include probability assessment for a large-scale emergency release. Safety analyses shall be accompanied with assessment of errors and uncertainties for the obtained results. Any software means used for safety analysis shall be certified.
1.2.10. Arrangement and reliability of safety-related systems and components, documentation and various works affecting the NPP safety shall be the subject of quality assurance activities at all stages of the complete NPP life cycle.
1.2.11. The NPP design shall provide for the engineering features and administrative measures aimed at prevention of accidents and mitigation of their consequences and assuring:
non-exceedance of the established limits for design basis accidents through the use of inherent self-protection properties and application of safety systems;
mitigation of consequences of any beyond design basis accidents through the use of special engineering features for beyond design basis accident management, application of any other suitable engineering features regardless of their initial purpose and implementation of administrative measures including beyond design basis accident management measures and plans for protection of the personnel and the public against the consequences of such accidents.
1.2.12. The established limits for design basis accidents shall not be exceeded in case of any initiating event considered in the NPP design in combination with a failure of any of the following safety system components independent of the initiating event in accordance with the single failure principle: an active component or a passive component with moving mechanical parts, or a passive component without any moving parts with the probability of failure to perform the safety function of 10-3 or more, or any human error independent of the initiating event.
In addition to a failure of any of the above-mentioned components independent of the initiating event all failures resulting from this single failure, failures resulting from the initiating event and also any failures of components undetectable in the course of the NPP operation and affecting the accident progression shall be taken into account.
Failures of components (systems they are included into) may be disregarded if a high level of their reliability is confirmed or within the established period of the component (system) shutdown for maintenance and repair.
The reliability level is deemed to be high when the component (system) reliability parameters are at least equal to the relevant parameters of the most reliable passive components of safety systems without any moving parts.
The permissible time limits for the component shutdown for maintenance and repair shall be determined on the basis of reliability analysis for the system the component is included into or on the basis of probabilistic safety analysis and shall be specified in the NPP design.
1.2.13. Ruptures of equipment casings and vessels manufactured and operated in accordance with the most stringent quality requirements stipulated by the federal standards and rules in the area of nuclear energy use regulating their arrangement and operation shall be excluded from initiating events for design basis accidents.
The NPP design shall substantiate that probability of the reactor pressure vessel breakdown within a year does not exceed 10-7.
1.2.14. The list of initiating events presented in the NPP SAR shall include all possible internal and external events violating normal operation of the NPP and not eliminated by the inherent self-protection properties of the reactor and principles of its design. Combinations of the NPP system (component) failures, human errors, internal or external impacts shall be included into the above-mentioned list of initiating events in the cases stipulated by the requirements of the federal rules and regulations in the area of nuclear energy use.
1.2.15. Generic lists of initiating events for analysis of design basis accidents for each reactor type shall be defined in the federal rules and regulations in the area of nuclear energy use. Final lists of initiating events for analysis of design basis accidents shall be presented in the NPP SAR.
Internal events with the estimated probability of occurrence within a year of 10-6 or less may be excluded from the list of initiating events for analysis of design basis accidents presented in the NPP SAR.
1.2.16. Generic lists of beyond design basis accidents for each reactor type shall be defined in the federal rules and regulations in the area of nuclear energy use.
Final lists of beyond design basis accidents (including severe ones) shall be presented in the NPP SAR. They shall include representative scenarios in order to define measures for management of such accidents. Representativeness of scenarios shall be provided by consideration of the NPP criticality level as well as potential operability or inoperability of safety systems and special-purpose engineering features for beyond design basis accident management.
Realistic (non-conservative) analysis of the above-mentioned beyond design basis accidents with assessment of development probabilities and consequences of beyond design basis accidents shall be given in the NPP SAR.
Analysis of beyond design basis accidents presented in the NPP SAR shall serve as the basis for development of action plans in order to protect the personnel and the public in case of any accidents and also for development of beyond design basis accident management guidelines.
1.2.17. The NPP safety targets are the following:
non-exceedance of cumulative severe accident probability for each NPP power unit within a year equal to 10-5;
non-exceedance of cumulative probability of a large-scale emergency release for each NPP power unit within a year equal to 10-7;
non-exceedance of cumulative severe accident probability for nuclear fuel storage facilities at the NPP (not included into the NPP power units) within a year equal to 10-5.
1.2.18. In case probability assessment for a large-scale emergency release does not confirm compliance with par. 1.2.17 of these General Provisions the NPP design shall provide for additional technical solutions (including special-purpose engineering features for beyond design basis accident management) in order to reduce the probability of accidents and to mitigate their consequences.
1.2.19. For beyond design basis accidents not eliminated by inherent self-protection properties of the reactor and the principles of its design (regardless of their probability) administrative measures for management of such beyond design basis accidents shall be developed including the measures aimed to reduce radiation exposure for the personnel, the public and the environment particularly by implementation of action plans for protection of the personnel and the public in case of an accident. Contents of the personnel protection plans shall comply with the federal rules and regulations in the area of nuclear energy use establishing the requirements for the standard contents of an action plan for protection of the personnel in case of any accident at a nuclear power plant.
1.2.20. The operating organization shall arrange development and implementation of quality assurance programs at all stages of the complete NPP life cycle and for this purpose develops a general quality assurance program in accordance with the legislation of the Russian Federation and controls activities of any companies performing works or rendering services to the operating organization (particularly surveying, design, engineering, research, construction, installation and commissioning companies, suppliers of systems and components, manufacturing plants of the NPP equipment). Companies performing works and rendering services to the operating organization shall develop their private quality assurance programs for the relevant activities within the framework of the general quality assurance program.
1.2.21. Safety culture shall be formed and supported for all employees and organizations related to siting, construction, operation and decommissioning of NPPs as well as design, development and manufacturing of their systems and components.
Safety culture shall be formed and supported in the following way:
the NPP safety prioritization over economic and production purposes;
selection, professional training and proficiency maintenance for senior managers and personnel in each safety-related area of activity;
strict adherence to discipline with clear distribution of authority and personal responsibility of managers and performers;
development and strict adherence to the requirements of quality assurance programs, standard operating procedures and process regulations and their regular updating with due regard for the experience gained;
managers at all levels shall create atmosphere of confidence and establish approaches to collective work as well as social and living conditions of the NPP personnel forming intestine necessity of positive attitude toward safety;
each employee shall understand the impacts of his/her activities on the NPP safety and any consequences that may result from failure to adhere or poor adherence to the requirements of quality assurance programs, standard operating procedures and job statements and process regulations;
self-control of safety-related activities by the employees;
each manager and employee shall understand inadmissibility of concealment of any errors in his/ her activities, the necessity for detection and elimination of their causes, the need for continuous self-improvement, study and implementation of the best practices particularly foreign ones;
establishment of the system of rewards and punishments based on the results of work activities that promotes transparency in the activities of employees and prevents concealment of any errors in their work.
1.2.22. The operating organization shall arrange management with due regard for safety purposes.
1.2.23. The operating organization shall assure the NPP safety including any measures for prevention of accidents and mitigation of their consequences, accounting and control of nuclear materials, radioactive substances and radioactive wastes, physical security of nuclear installations, nuclear materials, radioactive substances and radioactive wastes, radiological control of the environment in the sanitary control-protective area and the supervised area and also provide for the NPP usage only for the purposes it has been designed and constructed for.
The operating organization shall perform activities for the NPP safety enhancement in accordance with the plans developed with due regard for the results of safety analyses and operation experience in order to achieve the NPP safety targets specified in par. 1.2.17 of these General Provisions.
1.2.24. The operating organization shall establish organization departments in order to perform activities for construction and safe operation of the NPP directly on site, provide them with all necessary rights, funds, materials, equipment and human resources, regulatory documentation and scientific and technical support and determine their responsibility for such activities and also exercise surveillance over these activities.
1.2.25. The operating organization shall provide selection and training of the personnel as well as create the atmosphere where safety is considered as the affair of vital importance and the subject of personal responsibility for all employees and also exercise continuous control of the NPP safety.
1.2.26. The required organizational structure of management and the requirements for the NPP personnel proficiency level shall be substantiated in the NPP design and presented in the NPP SAR.
1.2.27. The design of each NPP shall provide for a personnel training center and a psycho-physiological examination laboratory with the educational and material resources, technical equipment for professional training and the staff of specialists necessary to assure high-quality training of the NPP personnel. A full-scale simulator shall be developed for one-type power units at each NPP and accepted for operation prior to delivery of fuel for the first power unit of the relevant type at this NPP.
1.2.28. Construction of the main buildings and structures of the NPP (NPP power units) may be commenced upon availability of the duly approved NPP design and subsequent to obtaining a NPP construction license in accordance with the legislation in the area of nuclear energy use as well as a construction permit in accordance with the urban development legislation.
1.2.29. The NPP design shall provide for technical and administrative measures of physical security assurance as well as for fire safety of the NPP. The physical security measures shall not impair the NPP safety assurance conditions under normal operation and in case of any anticipated operational occurrences including accidents.
1.2.30. The NPP design shall provide for communication and announcement means (particularly redundant ones) in order to organize the NPP management under normal operation conditions and in case of any design basis and beyond design basis accidents.
1.2.31. The operating organization shall manage the life span of any safety-related NPP components in accordance with the requirements of federal rules and regulations in the area of nuclear energy use.
II. Classification of systems and components
2.1. The NPP systems and elements are distinguished:
in terms of their purpose;
in terms of impact on safety.
Safety systems and components are also distinguished by the nature of their safety functions.
2.2. The NPP systems and components are classified by their purpose as follows:
normal operation systems and components;
safety systems and components;
systems and components of special-purpose hardware for beyond design basis accident management.
2.3. The NPP systems and components are classified by their impact on safety as follows:
safety-related systems and components;
other, non-safety related systems and components.
2.4. In terms of the nature of performed functions safety systems and components are classified as follows:
protective;
localizing;
supporting;
controlling.
2.5. Safety-related systems (components) include:
safety systems (components);
normal operation systems (components) capable of disturbing normal operation of the NPP or encumber elimination of any operational occurrences in case of their failure if the conditional probability of such failure escalation to a severe accident is 10-6 or more;
normal operation NPP systems (components) capable of causing exceedance of the established limits of radioactive substance releases or discharges or acceptable radioactive contamination levels in the working rooms of the NPP in case of their failure;
systems (components) provided in the NPP design for accident management within the first three days after the initiating event of the accident (or within any other period specified in the NPP design but at least three days);
radiological control systems (components of systems).
2.6. There are four safety classes according to importance of the NPP elements for safety.
Class 1. Class 1 includes fuel elements and NPP components, whose failures constitute initiating events for accidents resulting in damage of fuel elements with the maximum design limit <1> being exceeded while the safety systems perform their designed function.
--------------------------------
<1> The maximum design limits of fuel element failures shall be specified in accordance with the federal rules and regulations in the area of nuclear energy use.
Class 2. Class 2 includes the following components that are not included into Class 1:
components whose failures constitute initiating events resulting in FE damage without the maximum design limit exceedance while the safety systems perform their design function, with due regard for their failure frequency specified for design basis accidents;
safety system components whose single failures in case of a design basis accident result in exceedance of the design limits specified for such accidents.
Class 3. Class 3 includes safety-related NPP components not included into Classes 1 and 2.
Class 4. Class 4 includes non-safety-related NPP normal operation components not included into Classes 1, 2 and 3.
Components used to manage beyond design basis accidents and not included into safety classes 1, 2 and 3 also refer to safety class 4.
2.7. In case a component has features pertaining to different classes this component shall be referred to a higher safety class.
2.8. Devices (pipeline valves, throttling devices and other) separating components of different safety classes shall be referred to a higher safety class.
2.9. Safety classes of the NPP components shall be assigned by the RP and NPP designers in accordance with the requirements of these General Provisions.
2.10. Requirements for the quality of NPP components referred to safety classes 1, 2 and 3 and assurance thereof shall be defined in the regulations and other requlatory documents establishing requirements for their design and operation. In this case the above-mentioned regulatory documents shall set more stringent requirements for quality and quality assurance of the components referred to higher safety classes.
2.11. Pertinence of the components to safety classes 1, 2, 3 and 4, applicability of regulations and other regulatory documents to these components shall be substantiated and specified in the documentation for design, development and manufacture of the NPP systems and components and reflected in the NPP SAR.
2.12. Class designation of a component reflects its pertinence to safety classes 1, 2, 3, 4. Class designation is complemented by a symbol reflecting the nature of functions performed by the component:
N - normal operation component;
Z - protective;
L - localizing;
O - supporting;
U - safety system control element;
T - component of special-purpose hardware for beyond design basis accident management.
If a component has multiple purposes all the purposes are to be included in the component designation.
Examples of class designations: 2N, 3Z, 2NZ, 3T.
2.13. Classification characteristics of the NPP systems and components stipulated by these General Provisions shall be taken into consideration in any other classifications for the NPP systems and components developed in accordance with the requirements of federal rules and regulations in the area of nuclear energy use.
III. Basic safety principles implemented in the design of
a nuclear power plant and its systems
3.1. General requirements
3.1.1. Safety-related systems and components shall be designed and developed in accordance with the principles of these General Provisions and in compliance with any other federal rules and regulations in the area of nuclear energy use. The requirements of any other regulatory documents not referred to regulations may be applied to the extent they do not contradict the federal standards and rules in the area of nuclear energy use.
3.1.2. A NPP shall have safety systems intended to perform the following basic safety functions:
emergency reactor shutdown and maintenance of its subcritical state;
emergency heat removal from the reactor;
confinement of radioactive substances within the established limits.
Mutual impacts of safety systems preventing them from proper performance of their safety functions shall be eliminated. It is achieved inter alia by physical separation and functional independence.
The basic safety functions also include subcriticality assurance during storage and transportation of nuclear fuel as well as heat removal from nuclear fuel in the course of its storage and transportation within the NPP site which may be performed through the use of normal operation systems.
Emergency makeup systems shall be provided for SNF pools.
3.1.3. The NPP design shall provide for special-purpose engineering features to assure beyond design basis accident management.
3.1.4. The special-purpose engineering features for beyond design basis accident management specified in par. 3.1.3 of these General Provisions shall include hardware to assure performance of the basic safety functions in case of the following beyond design basis accidents:
failure of normal operation systems and safety systems removing heat from the reactor and nuclear fuel storage facilities to the ultimate heat sink;
failure of normal operation power supply systems in combination with failure of the emergency power supply systems.
The NPP design shall provide for the measures aimed to protect the above-mentioned special-purpose hardware against any external impacts as well as against any impacts that may occur during accidents (including beyond design basis ones), for example through the use of mobile equipment stored in safe locations.
3.1.5. The NPP design shall provide for the engineering features to control the RP and NPP state under accident conditions (particularly in case of severe accidents) as well as post-accident monitoring means. The scope of the RP and NPP control stipulated by the NPP design shall be sufficient for accident management.
3.1.6. The NPP design shall define devices and appliances for:
operability confirmation for systems and components (including any devices inside the reactor) and replacement of the equipment with exhausted life span;
testing of systems for compliance with the design parameters;
checking of the sequence of signal transmission and equipment actuation (including switching to emergency power supply sources);
metal condition monitoring (including weld joints) for equipment and pipelines;
metrological calibration of measuring instruments and measuring channels of the measurement systems for compliance with the design requirements.
3.1.7. The NPP design shall provide for the required sufficient fire protection means for the NPP including equipment for detection and extinguishing of the moderator and coolant burning. Automated functioning of fire-fighting systems provided in the NPP design shall be assured upon voltage supply to the NPP power unit equipment in the course of precommissioning works.
3.1.8. Safety-related systems and components shall be capable of performing their functions in the scope stipulated by the NPP design under any external natural impacts (earthquakes, hurricanes, tornadoes, floods and any other phenomena probable in the NPP location area), external human-induced impacts characteristic for the NPP site and (or) under any possible hydraulic, mechanical, thermal, chemical and other impacts caused by accidents when operation of the systems and components under consideration is necessary.
3.1.9. Measures for protection of safety systems and components as well as systems and components of special-purpose accident management hardware against common cause failures by implementation of diversity, redundancy and independence principles shall be considered and substantiated in the NPP design.
3.1.10. In the design of the NPP and RP systems (components) preference shall be given to the systems (components) based on the passive principle of action and inherent self-protection properties (self-regulation, heat retention, natural circulation and other natural processes) and also on the safe failure principle.
3.1.11. Safety systems shall be actuated automatically. Acceptability of the safety system actuation by the operator shall be substantiated in the NPP design.
3.1.12. The NPP design shall provide for the means to prevent human errors or to mitigate their consequences particularly in the course of maintenance and repair.
3.1.13. Multi-purpose use of safety systems and their components shall be justified. Combination of safety functions with normal operation functions shall not result in any violation of the NPP safety requirements and reduction of the required reliability in performance of safety functions.
Safety systems of any power unit at a multi-unit NPP shall be independent from safety systems of another power unit of the same NPP.
Sufficiency of special-purpose hardware for beyond design basis accident management in case of simultaneous accident occurrence at all power units of a multi-unit NPP shall be demonstrated.
3.1.14. Safety-related NPP systems and components shall, as a rule, be subject to direct and complete verification for compliance with the design characteristics during commissioning, after repair and periodically throughout the entire service life of the NPP.
In case direct and (or) complete verification is impossible that should be substantiated in the NPP design indirect and (or) partial verifications shall be performed. Sufficiency of any indirect and (or) partial verification shall be justified in the NPP design.
The NPP design shall provide for the possibility of technical diagnostics (checkup) of safety systems, special-purpose hardware for beyond design basis accident management and also safety-related normal operation components referred to safety classes 1 and 2 and the possibility of their representative testing.
3.1.15. Safety systems shall function in such a way so that their operation after actuation continues up to complete performance of their functions.
3.1.16. In case a safety-related system is arranged through the use of programmable digital devices the relevant standards, rules and methods for development, testing and verification of the programmable digital devices and software within the entire service life of the system and particularly in the course of software development shall be established and applied. All developments shall be subject to the quality assurance system. The NPP design shall provide for means of protection against unauthorized interference into software functioning.
3.1.17. Reliability analyses for performance of functions by safety-related systems as well as reliability parameters for safety-related components shall be presented in the NPP SAR. Reliability analysis shall be performed with due regard for common cause failures and human errors.
Reliability parameters of safety-related systems and elements shall be maintained in the course of operation by maintenance, repair and also metal condition control (including weld joints) performed with due regard for the requirements of federal rules and regulations in the area of nuclear energy use and with the frequency duly justified in the NPP design.
3.1.18. Operation limits and conditions, safe operation limits and conditions for all operational states of the NPP including power operation of the reactor, shutdown states and refueling shall be established and substantiated in the NPP design and reflected in the NPP SAR.
3.1.19. The NPP design shall specify requirements for chemistry regimes of the media in the NPP systems and components that should be observed in the course of operation in order to maintain integrity of physical barriers in the way of ionizing radiation and radioactive substance releases into the environment.
3.2. Core design and characteristics
3.2.1. FE damage limits (number and degree of fuel element damage) and the relevant levels of radioactivity for reactor coolant and (or) any other process media in the primary circuit by reference isotopes shall be established in the NPP design with due regard for the requirements of federal rules and regulations in the area of nuclear energy use.
Exceedance of the safe operation limits in relation to FE damage is unacceptable in case of any of the following operational occurrences (with due regard for operation of protection systems):
any single failures in the reactor plant control systems;
loss of power supply of the reactor coolant pumps;
disconnection of turbine generators and heat consumers;
loss of all normal operation power supply sources;
leakages in the reactor coolant circuit compensated by normal operation makeup systems;
failure of a steam generator safety valve (the system of steam supply pipelines to the turbine plant) to close after actuation.
3.2.2. The core shall be designed in such a way so that to provide absence of any deformations in the core components disturbing normal functioning of reactivity control and emergency reactor shutdown means or preventing from cooling of fuel elements with exceedance of the established design fuel element damage limits under normal operation conditions and in case of any anticipated operational occurrences up to design basis accidents inclusive.
3.2.3. The core with all its reactivity members shall be designed in such a way so that any reactivity changes due to control mechanisms and reactivity effects in any operational states and in case of design basis accidents do not result in uncontrolled increase of energy release in the core leading to damage of fuel elements above the established design limits.
3.2.4. Characteristics of the core, design of the reactor and any other equipment of the primary circuit (with due regard for operation of other systems) shall prevent formation of secondary critical amounts in case of severe accidents particularly with fuel melting.
If such possibility is present the technical measures shall provide non-exceedance of the probability value for a large-scale emergency release in accordance with par. 1.2.17 of these General Provisions.
3.3. Reactor coolant circuit
3.3.1. Equipment and pipelines of the reactor coolant circuit shall withstand without any breakage static and dynamic loads and thermal impacts occurring at any section of the circuit (with due regard for operation of protective safety systems and their possible failures in accordance with par. 1.2.12 of these General Provisions) in case of any operational occurrences up to design basis accidents inclusive particularly accidental energy releases into the coolant caused by:
sudden insertion of positive reactivity in case of the most efficient reactivity member ejection with the maximum velocity provided that such ejection is not prevented by design;
injection of the "cold" coolant into the core (with negative reactivity coefficient by the coolant temperature) or any other possible positive reactivity effect related to the coolant.
3.3.2. Functioning of the pressure reducing devices protecting the reactor coolant circuit against overpressure shall not result in any discharge of the primary circuit coolant outside the RP containment.
3.3.3. The "leak before break" concept shall be applied to the reactor coolant circuit in the NPP design. Engineering features and administrative measures for timely detection of any through cracks in the reactor coolant circuit pipelines and the RP bringing to the safe state before the crack reaches critical size shall be provided.
Any deviations from the requirements of this paragraph shall be justified in the NPP design.
3.3.4. Layout of equipment and the primary circuit geometry shall ensure development of natural circulation of the coolant in the primary circuit in case of loss of forced circulation, particularly during design-basis accidents.
3.3.5. The systems for purification of the reactor coolant from any radioactive contaminants shall be designed to operate up to the safe operation limit for FE damage in order to provide the NPP operation with the reasonably achievable low level of the reactor coolant activity.
3.3.6. The NPP design shall provide for the following:
measures to prevent accumulation of gases with explosion-hazardous concentrations in the primary circuit equipment and pipelines;
measures to prevent ingress of any foreign matter to the primary circuit;
hardware for monitoring of neutron poison nuclides content in the primary circuit coolant as well as in any media supplied to the primary circuit;
hardware for monitoring of activity in the primary circuit coolant and (or) any other process media of the primary circuit;
hardware for monitoring of the coolant level in the reactor;
engineering features to limit coolant leakage flows from the primary circuit;
hardware for monitoring of the primary circuit equipment and pipelines movements in case of any temperature change;
measures to eliminate adverse impact of the primary coolant heat insulation on operability of the safety systems.
3.4. Plant process control
3.4.1. General requirements
3.4.1.1. The following features shall be provided at each NPP unit in order to control process equipment of normal operation systems and safety systems:
MCR;
ECR;
NOCS;
CSS;
operator information support system;
independent information recording and storage means.
3.4.1.2. The RP and NPP design as well as the NPP SAR shal contain:
analysis of the responses of control systems to any possible failures in the control systems;
reliability analysis for operation of the control systems;
stability analysis for the automatic regulation circuit.
3.4.2. Main control room and emergency control room
3.4.2.1. The MCR shall provide the possibility for the operating personnel to control any normal operation systems (components) (including monitoring of operation limits and conditions), safety systems (components) as special-purpose hardware for beyond design basis accident management within the scope specified in the NPP design under normal operation conditions and in case of any anticipated operational occurrences including accidents.
3.4.2.2. The NPP design shall justify sufficiency of the provided measures to assure survivability, habitability and normal functioning of the MCR for the NPP power unit control in all normal operation modes as well as in case of any operational occurrences including design basis and beyond design basis accidents.
3.4.2.3. The issues of human-machine interface shall be solved in the optimal way in the MCR design. The NPP parameters to be controlled from the MCR shall provide unambiguous information to the operating personnel in relation to compliance with the NPP safe operation limits and conditions as well as on automatic actuation and functioning of safety systems.
3.4.2.4. Alarms output at the MCR shall be prioritized according to their safety relevance.
3.4.2.5. The following MCR features shall be provided in the NPP design:
chain fission reaction monitoring and control means for all modes and conditions in the core under normal operation (particularly in sub-critical state of the reactor in the course of refueling) and in case of any operational occurrences including accidents;
position indicators for the reactivity members, automatic control of the soluble poison concentration and state indicators for other reactivity control means.
3.4.2.6. Commands for control of the systems (components) generated by the automatic control system or remote control switches (or any other means) from the MCR and ECR panels shall be recorded automatically.
3.4.2.7. The following functions shall be performed from both MCR and ECR:
control of safety systems;
control of the reactor core bringing to sub-critical state and its maintenance in sub-critical state;
control of heat removal from the reactor and SNF pools to the ultimate heat sink;
control of conditions in the RP and the SNF pools.
3.4.2.8. Independence of the ECR from the MCR shall be provided, and sufficient survivability and habitability of the ECR shall be substantiated.
3.4.2.9. Measures to prevent any common cause failures of the MCR and the ECR shall be substantiated in the NPP design and presented in the NPP SAR.
3.4.2.10. Simultaneous control of the same equipment items from the MCR and the ECR shall be eliminated through the use of technical or administrative measures.
3.4.2.11. The MCR and the ECR shall be equipped with means for communication with protected command posts for emergency actions.
3.4.3. Normal operation control systems
3.4.3.1. The NPP unit NOCS shall provide process control in all NPP power unit operation modes with the quality parameters specified in the NPP design particularly with regard to reliability and metrological characteristics.
3.4.3.2. NOCS shall contain:
means of communication between the MCR, the ECR and the NPP operating personnel performing any works outside the control rooms;
means for collection, processing, documenting and storage of information sufficient to provide the possibility of timely and unambiguous definition of the initiating events of any operational occurrences (including accidents), their development, determination of the actual operation algorithm for safety systems and safety-related components (particularly instrumentation and control systems), deviations from regular algorithms and personnel actions;
means for detection of the primary circuit coolant leakages exceeding the values specified in the NPP design and their locations;
means for automated monitoring of radioactivity in the primary circuit coolant and (or) any other process media of the primary circuit.
3.4.3.3. The NPP unit NOCS shall provide automatic and (or) automated diagnostics of state and operation modes particularly for NOCS hardware itself (including software-based equipment).
3.4.3.4. The NPP unit NOCS shall be arranged in such a way so that to provide the most favorable conditions for the operating personnel to make correct decisions in relation to the NPP control and to minimize the probability of wrong decisions.
3.4.4. Control safety systems
3.4.4.1. CSSs shall perform their functions automatically upon occurrence of the conditions specified in the NPP design.
3.4.4.2. CSSs shall be designed in such a way so that to prevent the possibility of any safety system disabling by the operating personnel within 10-30 minutes after its automatic actuation but not to impair any correct actions of the operator stipulated by the process regulations, emergency operating procedures and beyond design basis accident management guidelines.
3.4.4.3. The possibility of remote actuation of safety systems and manual operation of valves in situ shall be provided at the NPP. A failure in automatic actuation circuit shall not prevent remote actuation and execution of safety functions. Impact on the minimal number of control elements shall be sufficient for remote and manual actuation.
3.4.4.4. The CSS arrangement shall minimize the possibility of spurious actuations. Remote control schemes for the mechanisms of safety systems shall provide for at least two logically related actions for their initiation (for example two switches or a patch board and a switch).
3.4.4.5. CSSs shall be separated from NOCSs to the extent providing that disturbances or failures of any NOCS component or channel would not affect the CSS capability to perform its functions.
Any failure of CSS elements for automatic control of safety system components shall not impair their control by the operator.
3.4.4.6. CSSs shall comply with the requirements of the following safety principles:
redundancy;
independence;
diversity.
Redundancy, independence and diversity shall be such that any single failure of the CSS would not impair its operability and protection against common cause failures in accordance with the requirements of these General Provisions would be provided.
3.4.4.7. CSSs shall provide for:
continuous automatic self-diagnostics of operability of the control systems;
regular technical diagnostics of operable condition of the CSS channels and diagnostics of the process equipment from the MCR and ECR panels in accordance with par. 3.1.14 of these General Provisions.
In case of any hardware and software failures and CSS damages alarms shall be output at the MCR and the ECR and actions aimed to assure the NPP safety shall be initiated.
3.4.5. Operator information support system.
Independent information recording and storage means
3.4.5.1. The operator information support system shall provide consolidated information on the NPP parameters characterizing the state of safety functions to the MCR personnel.
3.4.5.2. Independent means for recording and storage of the information necessaty to investigate accidents shall be provided. The above-mentioned means shall be protected from unauthorized access and shall retain their operability under normal operation conditions as well as in case of any anticipated operational occurrences including design basis and beyond design basis accidents. Extent of the information to be recorded and stored shall be substantiated in the NPP design.
3.5. Protective safety systems
3.5.1. The NPP design shall provide for protective safety systems aimed to assure reliable emergency shutdown of the reactor and its maintenance in sub-critical state in case of any operational occurrences up to design basis accidents inclusive.
3.5.2. Efficiency and fast response of the reactor trip systems shall be sufficient to limit energy releases to the level preventing exceedance of the FE damage limits specified in the design and to suppress positive reactivity caused by any reactivity effect or combination of reactivity effects under normal operation and in case of design basis accidents.
3.5.3. Emergency reactor tripping shall be provided regardless of availability and state of the power supply sources.
3.5.4. Systems for emergency heat removal from the reactor to the ultimate heat sink consisting of several independent channels shall be arranged within the protective safety systems.
Use of cooling systems (channels) intended for normal operation as the systems (channels) for emergency heat removal from the reactor is permitted provided that they comply with the requirements for safety systems.
3.5.5. Measures to prevent transition of the reactor to critical state and exceedance of permissible pressure in the reactor coolant circuit systems during actuation and operation of the emergency system of heat removal from the reactor shall be provided.
3.5.6. Actuation of protective safety systems shall not result in failures of the equipment of any normal operation systems. The permissible number of actuations for the protective safety systems (including spurious actuations) within the service life of the NPP power unit shall be substantiated in the design on the basis of their effect on the remaining life of the equipment.
3.6. Localizing safety systems
3.6.1. Localizing safety systems for confinement of radioactive substances and ionizing radiation in case of an accident within the borders stipulated in the NPP design shall be provided.
3.6.2. The reactor and any RP systems and components containing radioactive substances shall be entirely located inside the RP containment in order to confine any radioactive substances released during design basis accidents. Controlled release of radioactive substances out of the reactor plant containment is permitted in case of severe accidents only for prevention of the containment destruction provided that measures are taken to ensure radiation safety of public (through the use of the release filtration system, arrangement of shelters, evacuation of the public or any other measures).
3.6.3. Localizing safety systems shall be provided for each NPP power unit and perform the specified functions in case of design basis accidents as well as beyond design basis accidents considered in accordance with par. 1.2.16 of these General Provisions.
3.6.4. When heat removal systems with active elements (or passive elements with moving parts) are provided to prevent pressure rise inside the containment these systems shall consist of several independent channels.
3.6.5. All utility systems crossing the containment borders and presenting the possibility for release of radioactive substances outside the containment in case of an accident shall be equipped with isolating components in accordance with the requirements of federal rules and regulations in the area of nuclear energy use.
3.6.6. The acceptable leakage value for the containment shall be substantiated in the NPP design. Compliance of actual leak-tightness with the design one shall be confirmed prior to the first fueling of the reactor and checked in the course of operation with the frequency specified in the NPP design.
Testing of the containment in the course of the NPP power unit commissioning shall be performed under design pressure and the subsequent tests shall be performed under the pressure substantiated in the NPP design. Equipment located inside the containment shall withstand testing without any loss of operability. The method and hardware in order to test the containment for compliance with the design parameters shall be provided in the NPP design.
3.6.7. Hydrogen explosion protection shall be substantiated in the NPP design, and means to monitor physical and chemical parameters of hydrogen-containing mixtures in the containment atmosphere shall be provided.
3.7. Support safety systems
3.7.1. The NPP design shall provide for the necessary support safety systems performing the functions of the working medium and power supply to safety systems and arrangement of the required conditions for their functioning including heat transfer to the ultimate heat sink. Support safety systems may also include fire protection systems providing the required conditions for functioning of the safety systems in case of a fire or preventing fire from spreading to the safety systems.
3.7.2. Support safety systems shall have reliability parameters for performance of the specified functions sufficient to achieve the required functional reliability of the safety systems as stipulated in the NPP design in combination with reliability parameters of the safety systems supported by them.
3.7.3. Performance of the functions by support safety systems in accordance with the requirements of par. 3.7.1 of these General Provisions shall have priority over the internal protections of the support safety system components provided that it does not result in more severe consequences for the NPP safety; the list of non-disableable internal protections of the support safety system components shall be substantiated in the NPP design.
3.8. Storage systems for nuclear fuel
and radioactive wastes
3.8.1. Storage facilities for fresh nuclear fuel, SNF and radioactive wastes shall be provided at each NPP. Capacity of the SNF storage facilities at each NPP power unit shall be substantiated with due regard for the possibility of complete nuclear fuel unloading from the core at any moment of the NPP power unit operation.
Safety assurance in the course of fresh nuclear fuel, SNF and radioactive wastes handling shall be confirmed in the NPP SAR. Safety analysis for the storage facilities under normal operation conditions and in case of any anticipated operational occurrences including accidents shall be performed.
Nuclear and radiation safety in the course of nuclear fuel and radioactive wastes handling shall be assured in accordance with the requirements of federal rules and regulations in the area of nuclear energy use.
3.8.2. Any potential for criticality in the storage facilities for fresh nuclear fuel and SNF in the course of its storage and transportation shall be eliminated due to assurance of the relevant characteristics of storage facilities and transportation means.
3.8.3. Reliable systems of heat removal to the ultimate heat sink shall be provided for the SNF storage facilities in order to prevent damage of nuclear fuel and release of radioactive substances to the NPP rooms or to the environment exceeding the limits established in the NPP design.
The NPP design shall provide for transportation and handling operations and special-purpose devices for transportation of fresh nuclear fuel and SNF particularly for SNF removal from the NPP.
3.8.4. The NPP design shall contain analysis of the composition and quantity of solid, liquid and gaseous radioactive wastes under normal NPP operation conditions as well as assessment of the composition and quantity of radioactive wastes in case of design basis accidents performed in order to plan technical and administrative measures for RW handling within the post-accident period.
RW handling means providing for collection, sorting, processing, conditioning and storage of radioactive wastes under normal operation of the NPP and in case of any operational occurrences up to design basis accidents inclusive shall be arranged.
Storage facilities for solid and liquid radioactive wastes and handling systems for gaseous radioactive wastes shall be provided in the NPP design, and volume and storage time for non-conditioned and conditioned radioactive wastes at the storage facilities shall be substantiated.
Systems for purification of gaseous media prior to release into atmosphere and water purification prior to discharge into water bodies shall be provided in the NPP design.
3.8.5. The NPP design shall provide for technical and administrative measures to prevent formation of explosion-hazardous concentrations of hydrogen-containing mixtures in the nuclear fuel and RW storage facilities as well as the required hardware for monitoring of hydrogen-containing mixtures.
IV. Safety assurance for nuclear power plants during
the NPP power unit commissioning and in the course of operation
4.1. Arrangement of operation
and operational documentation
4.1.1. In accordance with the requirements of par. 1.2.24 of these General Provisions the operating organization shall establish organization departments at the NPP site, provide them with the necessary rights, funds and resources and also with regulatory documents and scientific and technical support.
The operating organization shall assure continuous surveillance over all activities affecting the NPP safety particularly based on self-assessment of the operating organization activity. The operating organization shall submit regular safety analyses for the NPP including consolidated results of the NPP operation inspections to the competent authority for safety regulation in the area of nuclear energy use and the authorized nuclear energy usage controlling agency.
4.1.2. The main document regulating safe operation of the NPP power unit is the Process Regulations for the NPP unit containing rules and basic techniques of operation, the general procedure for safety-related operations as well as safe operation limits and conditions.
The operating organization shall provide for development of the process regulations for the NPP power unit in cooperation with the NPP and RP designers according to the NPP design and the NPP SAR.
The process regulations for the NPP power unit and any amendments thereof shall be agreed between the organizations engaged in the development of the above-mentioned regulations and approved by the operating organization.
Operation of the NPP power unit with any violation of the process regulations for the NPP unit is prohibited.
The NPP power unit shall be shut down and brought into safe state as stipulated in the NPP design provided that the established safe operation limits and (or) conditions are met during the reactor functioning.
4.1.3. Design limits and conditions related to maintenance of chemistry for working media in the NPP systems and components shall be presented in the process regulations for the NPP power unit in order to assure compliance with the physical and chemical parameters specified in the NPP design during operation of the NPP systems and components.
4.1.4. Prior to precommissioning works the NPP management shall provide for development of operation manuals for systems and equipment on the basis of the approved process regulations for the NPP power unit and documentation of the equipment developers and the NPP and RP designers.
Operation manuals for the systems and equipment shall contain specific instructions for the personnel related to methods of working in the course of normal operation, operational occurrences and pre-accident situations.
Operation manuals shall be adjusted subsequent to the results of the NPP power unit commissioning.
4.1.5. The NPP management shall organize development, issuance and adherence to manuals and guidelines based on the process regulations for the NPP power unit and the NPP SAR and defining the personnel actions for safety assurance in case of any operational occurrences including emergency operating procedures for design basis accidents and the guidelines for management of beyond design basis accidents (particularly severe ones).
The personnel actions prescribed by the manuals and guidelines shall be based on characteristics of the occurring events and states of the RP and the entire NPP as well as on anticipated accident development. Anticipated actions shall be aimed to recover safety functions and to mitigate consequences of accidents.
4.1.6. Maintenance, repair, testing and inspections shall be provided in order to maintain operability of safety systems and prevent any failures of safety-related systems.
The operating organization shall provide for development of the process regulations for maintenance, repair, testing and inspections in cooperation with the NPP and RP designers according to the NPP design and the NPP SAR.
The safe operation conditions specified in the process regulations for the NPP unit shall be observed when removing safety systems from service for maintenance, repair as well as during testing and inspections.
Upon the request of any competent state regulatory authority for safety in nuclear energy use the operating organization shall perform unscheduled operability checks for safety systems, special-purpose hardware for beyond design basis accident management and also unscheduled condition monitoring for base metal and weld joints of the safety-related NPP systems and components.
4.1.7. The operating organization shall develop the list of nuclear-hazardous works for each NPP power unit as well as for any other nuclear facilities located at the NPP site.
Nuclear-hazardous works shall be performed in accordance with special work programs.
4.1.8. Measures shall be provided to exclude any possibility of unauthorized changes in the circuits, equipment and algorithms of the control safety systems.
Subsequent to maintenance safety-related components and systems shall be checked for operability and compliance with the design characteristics, and the results of such checks shall be documented.
4.1.9. The operating organization shall develop and implement the program to verify compliance of safety-related components and systems with the requirements of par. 3.1.8 of these General Provisions.
4.1.10. The operating organization shall establish and adhere to the procedure for maintenance, storage and review of the operation documentation.
Subsequent to any retrofitting and refurbishment of the NPP systems and components and prior to their operation the NPP administration shall provide for timely introduction of all necessary changes into the operation documentation.
The NPP project, as-build documentation for the NPP construction, test reports and as-build documentation for maintenance and repair of safety systems and components and safety-related components referred to safety classes 1 and 2 shall be stored at the NPP within the entire life cycle of the NPP.
4.1.11. Documented data on monitoring of the safe operation limits and conditions shall be stored at the NPP within two campaigns between refueling but at least two years. Prior to disposal of the records the results shall be included into regular safety reports for the NPP issued by the operating organization.
4.1.12. Any NPP testing not stipulated by the process regulations for the NPP power unit and operation manuals shall be classified as nuclear-hazardous works and performed in accordance with the programs containing measures for safety assurance in the course of such tests on the basis of safety analysis.
These testing programs shall be agreed with the RP and NPP designers and approved by the operating organization. Tests shall be permitted in accordance with the license conditions and performed according to the decision of the operating organization.
4.1.13. Any operational occurrences at the NPP including accidents shall be investigated in accordance with federal rules and regulations in the area of nuclear energy use. The operating organization shall develop and implement measures to prevent any repeated occurrences due to the causes that have previously resulted in operational occurrences at the NPP.
4.1.14. The operating organization shall submit information on any operational occurrences at the NPP to the competent state regulatory authority for safety in nuclear energy use and the authorized nuclear energy usage controlling agency. Unimpaired access for any representatives of the competent state regulatory authority for safety in nuclear energy use to the operation documentation containing the data on the above-mentioned occurrences shall be provided in accordance with the effective legislation.
The operating organization shall provide for storage of the materials on investigation of operational occurrences at the NPP within the entire service life of the NPP.
4.1.15. In the course of the NPP operation the operating organization shall provide collection, processing, analysis, filing and storage of the information on any failures of safety-related components and wrong actions of the personnel as well as its prompt submittal to all organizations concerned (including the NPP and RP designers) in accordance with the established procedure. In this case special attention shall be paid to the events indicating severe accidents in order to provide the possibility for implementation of the required corrective measures prior to occurrence of such events.
4.1.16. In case the operating organization detects any occurrence (event) indicating a severe accident with the conditional probability of escalation into a severe accident of 10-3 or more <1>, the operating organization shall develop the action plan for prevention of similar occurrences (events) and also substantiate the possibility for power operation of the NPP unit within the period prior to implementation of the measures specified in this action plan. The above-mentioned plan and substantiation shall be submitted by the operating organization to the competent state regulatory authority for safety in nuclear energy use for review.
--------------------------------
<1> If the unrealized part of the accident sequence leading to a severe accident includes any initiating event the specified conditional probability value shall be referred to the period of 1 year.
4.1.17. Regular safety assessment with the interval of 10 years shall be performed for power units of NPPs with the operation licenses granted for more than ten years in accordance with the established procedure with due regard for any changes in the NPP site characteristics, ageing of the NPP components (including equipment and civil structures), refurbishment, operation experience, state of the art in science, technology and production as well as any modifications in the requirements of regulatory documents in order to confirm the possibility for further safe operation of the NPP.
4.1.18. Subsequent to the results of the life management activities for safety-related NPP components and analysis of the NPP power unit compliance with the requirements of federal rules and regulations in the area of nuclear energy use the operating organization may raise the question on prolongation of the NPP unit service life beyond the service life specified in the design. A new operation license for the NPP power unit shall be obtained to operate the NPP power unit within this additional period.
4.2. Commissioning of a NPP power unit
4.2.1. Commissioning of a NPP power unit shall be performed with due regard for the requirements of these General Provisions and other regulations.
Requirements to the sequence and scope of the works performed at the stage of pre-commissioning, physical start-up, power start-up and pilot operation particularly the procedure for checking of the safety-related NPP systems and components for compliance with the design parameters (including acceptance criteria) shall be established and substantiated in the NPP design and presented in the NPP SAR.
The operating organization shall provide for development and implementation of the NPP power unit commissioning program based on the NPP SAR.
4.2.2. Equipment and devices as well as programs and methods for the following purposes shall be ready and checked for safety-related systems and components prior to physical start-up commencement:
operability confirmation for systems and components (including any devices inside the reactor) and replacement of the equipment with exhausted life span;
testing of systems for compliance with the design parameters;
checking of the sequence of signal transmission and equipment actuation (including switching to emergency power supply sources);
metal condition monitoring (including weld joints) for equipment and pipelines;
metrological calibration of measuring instruments and measuring channels of the measurement systems for compliance with the design requirements.
4.2.3. Pre-commissioning works, physical and power start-up and pilot operation shall confirm that the entire NPP as well as safety-related systems and components are arranged and functioning in accordance with the NPP design and any revealed defects are eliminated.
The NPP management shall provide for development of the pre-commissioning, physical start-up, power start-up and pilot operation programs and their agreement with the NPP and RP designers. The programs shall be approved by the operating organization.
The documents regulating pre-commissioning works, physical and power start-up and pilot operation shall contain the list of nuclear-hazardous works and the list of measures aimed to prevent any nuclear accidents.
4.2.4. Actual characteristics of safety-related systems shall be determined and documented, characteristics of the equipment and systems and setpoints of the control systems shall be adjusted in the course of the NPP power unit commissioning. Design limits and conditions and operation documentation shall be also adjusted to reflect actual characteristics of the systems and equipment.
The list of characteristics to be documented shall be defined in accordance with the relevant testing programs.
4.2.5. The commissioned NPP unit shall be isolated from the operating NPP units and any sites where construction works are in progress so that any current works and potential occurrences at the construction sites as well as operational occurrences (including design basis accidents) at the operating NPP units world not affect safety of the commissioned NPP unit and any occurrences at the commissioned NPP unit would not have any adverse effect on safety of the operating NPP units. Sufficiency of measures for isolation of the commissioned NPP unit from the operating NPP units shall be substantiated in the NPP design and reflected in the NPP SAR.
4.2.6. The preliminary version of the final NPP SAR shall be developed prior to delivery of nuclear fuel to the NPP power unit.
Subsequent to completion of pilot operation the final version of the NPP SAR shall be developed with due regard for the results obtained during physical start-up, power start-up and pilot operation of the NPP unit.
4.2.7. The first delivery of nuclear fuel to the site, physical start-up and power start-up of the NPP unit and pilot operation shall be permitted in accordance with the conditions for transition from one milestone to another specified in the operation license conditions and subsequent to inspection by the competent state regulatory authority for safety in nuclear energy use with regard to the NPP readiness for these stages of the NPP power unit commissioning subject to availability of plans for protection of the personnel and the public in case of any accident at the NPP and their support.
4.3. Recruitment and training of personnel
4.3.1. Prior to delivery of nuclear fuel to the NPP the NPP shall be staffed with the personnel having the required skills and duly admitted to unattended works in accordance with the procedure established by the operating organization.
In the course of the NPP operation the workplaces shall be occupied by the personnel duly admitted to unattended works at the relevant positions; the minimal requirements for the quantity and composition of the personnel shall be established in the NPP design and presented in the NPP SAR and the process regulations for the NPP unit operation.
4.3.2. Persons from the NPP personnel shall perform certain activities in the area of nuclear energy use only against presentation of permits granted by the state regulatory authority for safety in nuclear energy use.
4.3.3. Qualification requirements for the NPP personnel without any need to obtain permits from the state regulatory authority for safety in nuclear energy use shall be established by the operating organization.
4.3.4. The operating organization shall provide selection, training, admittance to unattended works and proficiency maintenance for the NPP personnel. The system of the NPP personnel selection and training shall be aimed at achievement, control and maintenance of their proficiency level required to assure safe operation of the NPP in all modes and to perform any activities for mitigation of accident consequences in case of their occurrence.
Formation of safety culture in the operating personnel shall be an integral part of training.
4.3.5. Equipment (including various types of simulators) permitted for use in the NPP personnel training shall be used for professional training of the NPP personnel in order to exercise practical NPP operation skills. Special attention shall be paid to drilling of the actions in case of any potential operational occurrences at the NPP (including accidents) and consideration of the operation experience.
4.3.6. The NPP personnel shall be subject to medical examination before admittance to unattended works as well as regularly. The NPP management shall define the list of the operating personnel positions subject to additional pre-shit medical examination. Health of the NPP personnel shall provide performance of their duties for the NPP operation.
4.3.7. In case of any retrofitting of the NPP systems and components the NPP management shall provide for timely introduction of any necessary changes to the operation documentation as well as familiarization of the relevant personnel with these changes including any professional training and drilling if required.
4.3.8. The NPP personnel shall be prepared for actions in case of any design basis and beyond design basis accidents.
4.3.9. Actions of the NPP personnel in case of beyond design basis accidents shall be regulated by the special guidelines to be developed in accordance with par. 4.1.5 of these General Provisions with due regard for the analyses of design basis and beyond design basis accidents.
4.3.10. Emergency response drills shall be held regularly in order to prepare the personnel for actions under accident conditions.
4.3.11. The operating organization shall develop methods and programs for preparation and performance of emergency response drills in order to exercise the actions under accident conditions and organize the above-mentioned drills.
4.4. Radiation safety in the course of operation
4.4.1. Radiation protection of the personnel and the public in the course of the NPP operation shall be assured due to compliance with the legislation of the Russian Federation in the area of radiation safety as well as the requirements of federal standards and rules in the area of nuclear energy use and other regulations.
4.4.2. The system to monitor integrity of the physical barriers on the way of ionizing radiation and radioactive substance releases into the environment shall be provided for control of compliance with the specified safe NPP operation limits.
4.4.3. The NPP design shall provide for radiological control systems that should assure measurement of the controlled parameters characterizing the radiation situation in the NPP rooms and at the site as well as in the sanitary control and protection area and in the supervised area within a certain scope in all NPP operation modes, in case of design basis and beyond design basis accidents and also in the course of the NPP decommissioning.
4.4.4. The NPP design shall provide for continuous measurement of ionizing radiation dose rates, wind velocity and other meteorological parameters as well as regular measurement of fallout density in the sanitary control and protection area and the supervised area in order assess and predict the radiation situation in the local environment under normal operation of the NPP and in case of any operational occurrences including design basis and beyond design basis accidents. Engineering features for such assessment and prediction shall be provided.
4.4.5. The NPP management shall provide control of exposure doses for the NPP personnel and the personnel of any other organizations engaged in maintenance, repair and testing of the systems and components and also development and implementation of measures aimed to reduce the personnel exposure doses to the reasonably achievable level.
4.4.6. The NPP management shall provide for accounting and control of nuclear materials, radioactive substances and radioactive wastes particularly fresh nuclear fuel and SNF, dismantled radioactive equipment, contaminated tools, clothes, production wastes and other sources of ionizing radiation with due regard for the requirements of regulatory documents.
4.4.7. The operating organization shall provide safe handling of radioactive wastes including their storage within the established time limits for interim RW storage.
Prior to expiry of the interim RW storage time the operating organization shall bring the radioactive wastes into compliance with the acceptance criteria for their disposal by its own efforts or through engagement of any specialized organizations.
4.5. Action plans for protection of the personnel and the public
in case of accidents and accident management
4.5.1. Action plans for protection of the personnel and the public in case of any accident at the NPP with due regard for radiological consequences of beyond design basis accidents shall be developed and ready for implementation prior to delivery of nuclear fuel to the nuclear power plant. The plans shall be developed on the basis of design characteristics and parameters of the NPP, the final list of beyond design basis accidents developed in accordance with the requirements of par. 1.2.16 of these General Provisions, criteria for making decisions of the measures for protection of the personnel and the public in case of any accident at the NPP and with due regard for economic, natural and other characteristics and peculiarities of the territories and the actual risk of an emergency.
4.5.2. Action plans shall include measures in case of simultaneous beyond design basis accidents at several NPP units or any other nuclear facilities located at the NPP site accompanied by disturbances of infrastructure outside the NPP site (for example blockage of access roads, failures of the NPP power supply, communication failures).
4.5.3. Prior to delivery of nuclear fuel to the NPP it is necessary to engage the main and redundant facilities for the NPP communication with the operating organization, the competent state regulatory authorities for safety in nuclear energy use and control bodies specially authorized to solve problems related to protection of the public and territories against emergencies and formed under executive government bodies of the constituent entity of the Russian Federation and local government bodies.
4.5.4. Action plans for protection of the personnel and the public shall be developed, approved and supported with all required resources.
4.5.5. The action plan for protection of the personnel and the public in case of any accident at the NPP shall be developed by the NPP management in accordance with the requirements of federal rules and regulations in the area of nuclear energy use. It shall provide for coordination of actions between the NPP and external organizations, bodies of internal affairs, the state fire-fighting services, control bodies for protection of the public and territories against emergencies, medical institutions, local government bodies within the site and the protective actions planning zone. The NPP management shall be responsible for maintenance of instant readiness and implementation of the plan.
4.5.6. The action plan for protection of the public in case of any accident at the NPP shall provide for coordination of actions between the facility-based and community-based forces of emergency agencies of the constituent entities of the Russian Federation and the local government bodies as well as any ministries and departments engaged in implementation of measures for protection of the public and recovery from the accident.
4.5.7. Action plans for protection of the personnel and the public in case of any accident at the NPP shall specify the levels of emergency preparedness and intervention levels; it is necessary to define who, when and via what communication means shall notify on the accident and beginning of the relevant plan implementation and what organizations are to be notified. The plans shall provide for technical and administrative measures for their implementation.
4.5.8. Prior to delivery of nuclear fuel to the NPP protected command posts for emergency actions with the required equipment, instrumentation and communication means shall be arranged and maintained in constant preparedness in order to manage implementation of plans according to par. 4.5.6 and 4.5.7 of these General Provisions in case of any accidents.
4.5.9. In the course of beyond design basis accident management measures shall be taken to bring the NPP power unit back to controlled state when the chain fission reaction is stopped, continuous fuel cooling and confinement of radioactive substances within the established borders is assured; it is also necessary to take measures aimed to prevent escalation of the beyond design basis accident and to mitigate its consequences particularly to protect the reactor plant containment against destruction and to maintain its operability.
V. Decommissioning of the nuclear power plant
5.1. Decommissioning of the NPP (a NPP power unit or any other nuclear facilities located at the NPP site) shall be planned in the course of the NPP siting, design, construction and operation.
5.2. The NPP design shall provide for the measures aimed at safe decommissioning of the NPP power unit.
5.3. Planning of the NPP decommissioning in the course of siting, design and construction shall be arranged by development and improvement of the NPP decommissioning concept that should be presented in the NPP SAR.
5.4. Planning of the NPP decommissioning in the course of operation shall be arranged by regular review (adjustment) of the NPP decommissioning concept presented in the NPP SAR. In this case the NPP operation experience shall be taken into consideration including the experience in performance of repair works, any refurbishment and retrofitting, the results of any inspections of the NPP technical and radiological conditions, the results of analysis for any accidents that have occurred and any other factors.
5.5. The operating organization shall develop the NPP power unit decommissioning program based on the NPP decommissioning concept as well as analysis of design documentation and operation experience not later than five years prior to expiry of the design service life of the NPP (the NPP power unit, any other nuclear facility located at the NPP site).
5.6. Integrated engineering and radiological inspection of the NPP (the NPP power unit or any other nuclear facility located at the NPp site) shall be performed prior to decommissioning by the commission assigned by the operating organization. The decommissioning program for the NPP (the NPP power unit or any other nuclear facilities located at the NPP site) shall be updated subsequent to this integrated NPP inspection.
5.7. The operating organization shall develop the NPP power unit decommissioning project and prepare the NPP SAR for the NPP power unit decommissioning based on the results of the integrated engineering and radiological inspection.
5.8. The NPP power unit shut down for decommissioning shall be considered as operating up to complete removal of all nuclear materials including fresh nuclear fuel and SNF. All requirements for the personnel and documentation shall remain within this period as for an operating NPP power unit.
Reduction of the maintenance scope, decommissioning of individual systems and components, decrease in the number of operating personnel in the course of preparation for decommissioning shall be substantiated in the NPP SAR.
5.9. Preparation for unscheduled decommissioning of the NPP power unit shall be performed with due regard for the requirements stipulated in par. 5.6-5.8 of these General Provisions.
5.10. Safety shall be assured in the course of the NPP power unit decommissioning in accordance with the requirements of federal rules and regulations in the area of nuclear energy use.
Appendix 1
to federal rules and regulations
in the Area of Atomic Energy Use
"General provisions for safety assurance
at nuclear power plants”,
approved by Order of the Federal
Environmental, Industrial
and Nuclear Supervision Service
dated December, 17, 2015 No. 522
ABBREVIATIONS
NPP | - | Nuclear Power Plant |
MCR | - | Main Control Room |
NF | - | Nuclear Facility |
NPP SAR | - | Nuclear Power Plant Safety Analysis Report |
SNF | - | Spent Nuclear Fuel |
ST | - | Software Tool |
RW | - | Radioactive Waste |
ECR | - | Emergency Control Room |
RP | - | Reactor Plant |
FE | - | Fuel Element |
CSS | - | Control Safety Systems |
NOCS | - | Normal Operation Control Systems |
Appendix 2
to federal rules and regulations
in the Area of Atomic Energy Use
"General provisions for safety assurance
at nuclear power plants”,
approved by Order of the Federal
Environmental, Industrial
and Nuclear Supervision Service
dated December, 17, 2015 No. 522
GENERAL TERMS AND DEFINITIONS.
1. Accident at the NPP (accident) - an operational occurrence at the NPP with a release of radioactive substances and (or) ionizing radiation beyond the borders stipulated in the NPP design documentation for normal operation in the amounts exceeding the established safe operation limits; an accident is characterized by the initiating event, development scenarios and consequences.
2. The NPP management (the NPP administrative management) - managers and other employees of the NPP whom the operating organization has endowed with the relevant rights, duties and responsibilities for the NPP safety in the course of the NPP construction, operation and decommissioning.
3. Active system (component) - any system (component) with its functioning depending on normal operation of any other system (component) for example a control system, a power supply system or any other system.
4. Nuclear plant - facilities and complexes with nuclear reactors, the necessary systems, devices and equipment for power production in the specified modes and conditions of use located within the territory defined in the NPP design with the required workers (personnel) and documentation; a NPP may also include storage facilities for nuclear fuel and radioactive wastes.
5. Heat supply nuclear plant - a nuclear plant intended to produce thermal energy for the purpose of heating and hot water supply.
6. Nuclear power plant - a nuclear plant intended for generation of electric power.
7. Nuclear power and process plant - a nuclear plant intended for generation of electric power and energy for production purposes.
8. Software tool validation - the regulated procedure involving confirmation of the possibility to use the ST in the specified field of application and also obtaining the design parameter values with certain tolerance through the use of the ST.
9. NPP safety (nuclear and radiation safety of the NPP) - the NPP property to provide reliable protection of the personnel, the public and the environment against any radiation exposure unacceptable in accordance with the federal rules and regulations in the area of nuclear energy use.
10. Biological protection - barriers (including civil structures) intended to protect against ionizing radiation.
11. NPP power unit - the part of a NPP with a RP performing the NPP function to the extent defined in the NPP design.
12. Main control room - the part of a NPP power unit located in the dedicated rooms provided in the NPP design and intended for centralized automated control of processes performed by the operating personnel and automatic devices.
13. Large-scale emergency release - release of radioactive substances into the environment in case of any accident at the NPP when it is necessary to implement measures for protection of the public within the initial stage of the accident at the border of the protective actions planning zone established in accordance with the requirements of NPP siting regulations and rules and outside it.
14. Commissioning of the NPP power unit - the process when the NPP (NPP power unit) systems and equipment begin to function and their compliance with the NPP design and operational availability is checked; the process is completed with obtaining of the facility commissioning permit according to the procedure established by the urban planning legislation.
Commissioning of the NPP power unit is divided into stages: pre-commissioning works, physical start-up, power start-up, pilot operation.
15. Probabilistic safety analysis - qualitative and quantitative analysis of the NPP safety performed in order to define the probability of accident development scenarios and end states particularly the probability of severe accidents and large-scale emergency releases.
16. External impacts (events) - impacts of any natural phenomena and human activities characteristic for the NPP site, for example earthquakes, high and low level of surface and ground water, hurricanes, accidents with air, water and land transport, fires, explosions at any facilities adjacent to the NPP, etc.
17. Internal impacts (events) - any impacts in the course of operational occurrences caused by failures of NPP components or human errors including shock waves, jets, missiles, changes in the media parameters (for example pressure, temperature, chemical activity), fire and flooding.
18. Inherent RP self-protection - the property to provide safety based on natural responses, processes and characteristics.
19. Explosion protection (hydrogen) - engineering and administrative measures aimed to prevent detonation of hydrogen-containing mixtures in the reactor plant equipment and within the space enclosed by the reactor plant containment, as well to mitigate impact of hydrogen-containing mixture burning on the reactor plant containment and other safety-related NPP systems and components under normal operation of the NPP and in case of any operational occurrences including accidents.
20. Decommissioning of the NPP power unit - activities performed after removal of nuclear fuel and other nuclear materials from the NPP power unit and aimed to achieve the specified end state of the NPP power unit eliminating usage of the NPP power unit as a source of energy and assuring safety of the personnel, the public and the environment.
21. Containment - the set of the NPP power unit components (including civil structures) enclosing the space around the reactor plant or any other facility containing radioactive substances and forming the boundary as provided by the NPP design in order to prevent releases of radioactive substances and ionizing radiation into the environment in the amounts exceeding the established limits.
22. Deterministic safety analysis - the NPP safety analysis in the specified operational states of the NPP, postulated initiating events and the specified state of systems and components affecting the accident development scenarios which is performed to confirm compliance of the NPP with the established safety criteria and (or) design limits.
23. Survivability - the property of systems and components particularly control rooms to perform their functions in spite of any sustained damage.
24. Dependent failure - any failure of a system (component) resulting from other failure or event.
25. Beyond design basis accident - an accident caused by initiating events not considered for design basis accidents or accompanied by additional failures of safety system components as compared to design basis accidents in excess of a single failure and implementation of erroneous personnel decisions.
26. Protective safety systems (components) - safety systems (components) intended for performance of the functions to prevent or limit damage of nuclear fuel, FE claddings, equipment and pipelines containing radioactive substances.
27. Initiating event - a single failure in the NPP system (component), internal or external impact or human error, or combination of the above-mentioned events resulting in operational occurrences at the NPP and capable of resulting in deviation from the safe operation limits and (or) conditions.
28. System channel - part of the system performing the system function to the extent specified in the NPP design.
29. Personnel qualification - proficiency level of any person from among the managers and employees of the NPP and other organizations carrying out any works that affect the NPP safety including basic vocational education, professional knowledge and skills as well as work experience assuring high quality and safety of the NPP operation in the course of the job duty performance.
30. Accident end state - controlled state of the NPP systems and components established subsequent to any accident that may be maintained within an indefinite period of time.
31. Ultimate heat sink - external medium (a water body or atmosphere) where nuclear fuel energy release heat is transferred to.
32. Conservative approach - approach to design and development when more unfavorable results shall be obtained in analysis of accidents due to selection of the values of the NPP and the NPP site parameters and characteristics and (or) by any other methods.
33. Reactor coolant circuit (primary circuit) - the circuit together with the volume control system (if any) intended for the coolant circulation through the core in the operation modes and conditions established in the NPP design.
34. "Leak before break" concept - approach to design of pipelines based on the proven crack propagation mechanism when a leak detected through the use of engineering features provided in the NPP design appears before the crack reaching the critical size.
35. Safety criteria - values of parameters and (or) characteristics of the NPP used to substantiate its safety and established by regulatory documents or in the NPP design. Safety criteria established in the NPP design shall not contradict the requirements of regulatory documents.
36. Safety culture - the set of characteristics and peculiarities of the activities of organizations and behavior of individuals which assigns the highest priority to NPP safety issues according to extent of their significance.
37. Localizing safety systems (components) - safety systems (components) intended for prevention or limitation of radioactive substance and ionizing radiation release outside the borders established in the NPP design as well as their discharge to the environment.
38. Anticipated operational occurrence at the NPP - any disturbance in the NPP operation with deviation from the established operation limits and (or) conditions. In this case other limits and (or) conditions established in the NPP design particularly safe operation limits and (or) conditions may be also exceeded.
39. Independent systems (components) - systems (components) where a failure of any system (component) does not result in a failure of other system (component).
40. Undetectable failure - any failure of a system (component) not manifested at the moment of its occurrence in the course of the NPP operation and not detected by the specified control means in accordance with the maintenance and inspection regulations.
41. Normal operation - the NPP operation within the operation limits and conditions defined in the NPP design.
42. Quality assurance - scheduled and systematically implemented activities intended to perform all works related to the NPP construction and operation in the established manner and to make their results comply with any requirements imposed upon them.
43. Supporting safety systems (components) - safety systems (components) intended to supply the safety systems with power and working media and to create conditions for their functioning.
44. Habitability - the set of factors characterizing conditions of the personnel staying in the room and providing the possibility for the personnel to perform their professional duties normally.
45. Pilot operation - the stage of the NPP (NPP power unit) commissioning subsequent to power start-up completed with obtaining of the NPP power unit operation permit in accordance with the established procedure.
46. Common cause failure - failures of systems (components) occurring as a result of a single failure or human error or internal or external impact (event) or due to other reason.
47. Human error - any single unintended wrong action or single omission of a correct action in control of the NPP systems and components, or any single unintended wrong action or single omission of a correct action in maintenance or repair of the NPP systems and components.
48. Erroneous decision - wrong performance or failure of the NPP personnel to perform a set of prescribed actions due to incorrect assessment of the processes in progress.
49. Passive system (component) - a system (component) with the functioning associated only with the event initiating its actuation and independent from operation of any other system (component), for example a control system or a power supply system.
In accordance with their design features the passive systems (components) are classified into passive systems (components) with mechanical moving parts (for example check valves) and passive systems (components) without mechanical moving parts (for example pipelines and vessels).
50. Fuel element damage - exceedance of at least one of the damage limits established for fuel elements.
51. Cliff edge effect - considerable sudden deterioration of the NPP (NPP power unit) safety caused by insignificant changes of the parameters.
52. Accident consequences - the radiation situation caused by the accident and inflicting harm and losses due to exceedance of the established radiation exposure limits for the personnel, the public and the environment.
53. Pre-accident situation - any deviation from the safe operation limits and (or) conditions which has not developed into an accident.
54. Severe accident indication - any deviation of the NPP from the design characteristics detected in the course of operation or any event occurring in the course of operation which has not resulted in a severe accident but gives evidence of a serious fault in the equipment, the NPP design or the NPP operation, or forms a significant part of the accident sequence capable of leading to a severe accident.
55. NPP safe operation limits - the values of the process parameters established in the NPP design any deviations from which can lead to an accident.
There are safe operation limits with regard to radiological parameters and safe operation limits related to other process parameters. Exceedance of the safe operation limits with regard to radiological parameters is an accident.
56. Pre-commissioning works - the NPP power unit commissioning stage when the NPP systems and components completed through construction and installation are brought to operational availability with inspection of their correspondence to the criteria and characteristics specified in the NPP design; the stage is completed with the NPP power unit readiness for physical start-up.
57. Safe failure principle - the principle stating that in case of any system or component failure the nuclear plant (NPP power unit) shall transfer to the safe state without any necessity for initiation of any actions via the control safety system.
58. Single failure principle - the principle stating that the system shall perform the preset functions in case of any initiating event requiring its operation and in case of any component failure in this system considered in the NPP design and independent of the initiating event.
59. The principle of independence - the principle for reliability enhancement by functional and (or) physical separation of the channels (components) whereas a failure of any channel (component) does not result in the failure of another channel (component).
60. The principle of diversity - the principle for reliability enhancement by application of two or more systems or components for performance of a safety function having different designs or operation principles in order to reduce the probability of a common cause failure.
61. The principle of redundancy - the principle for reliability enhancement by application of several similar or different components (channels, systems) so that each of them shall perform the required function regardless of the state (including failure) of other components (channels, systems) intended to perform this function.
62. Component or system check (inspection) - control of a system or component in order to determine their operable or non-operable condition, to detect any faults and to confirm the design characteristics.
63. Design basis accident - an accident with the initiating events and end states defined in the NPP design and the provided safety systems aimed to assure mitigation of its consequences to the limits established for such accidents in case of any failure of a safety system component independent from the initiating event and considered in the NPP design or in case of a human error independent from the initiating event.
64. Design limits - the values of parameters and characteristics of the systems (components) and the entire NPP established in the NPP design for normal operation and anticipated operational occurrences.
65. Accident development scenario - the sequence of states of the NPP systems and components in the course of accident development.
66. The NPP (RP) designers - organizations developing the NPP (RP) design and providing its scientific and technical support (particularly engineering one) at all stages of the entire NPP (RP) life cycle.
67. Reactor plant - a complex of the NPP (NPP power unit) systems and components intended for conversion of nuclear energy into thermal one and including the reactor and any systems and components directly connected to it and necessary for its normal operation, emergency cooling, emergency protection and maintenance in the safe state subject to performance of the required auxiliary and supporting functions by other NPP systems. The RP boundaries shall be established in the NPP design.
68. Emergency control room - the part of the NPP power unit located in the dedicated room as per the NPP design and intended for continuous monitoring of the reactor conditions, bringing of the reactor into sub-critical state, cooldown of the reactor and its maintenance in the sub-critical cold state for an indefinite period of time, actuation of safety systems where necessary and also for control of heat removal from the SNF pool in case of the MCR failure.
69. Repair - a set of operations for restoration of operable or serviceable state of the facility (systems and components) and/or extending of its operational life.
70. Self-assessment - analysis performed by the operating organization, the administrative management or the NPP personnel in order to assess compliance with the requirements related to the NPP safety as well as to evaluate efficiency and adequacy of management for safety purposes.
71. NPP system (system) - the set of NPP components intended to perform the prescribed functions.
72. Safety systems (components) - systems (components) intended to perform safety functions in case of design basis accidents.
73. Normal operation systems (components) - systems (components) intended for normal operation.
74. State of the art in science, technology and production - the package of scientific and technical knowledge, technological, design and engineering developments in certain fields of science and technology confirmed by scientific researches and practical experience and reflected in scientific and technical materials and (or) implemented in industries.
75. NPP construction - the process of arrangement of the NPP (NPP power unit) buildings, structures, facilities and complexes including construction and installation works and the NPP power unit commissioning.
76. Special-purpose hardware for beyond design basis accident management - systems (components) provided in the NPP design for management of beyond design basis accidents.
77. Maintenance - the set of operations for maintenance of operability and good operating condition of the facility (systems and components) in the course of its intended use, in the standby mode, during storage and transportation.
78. Severe accident - a beyond design basis accident with damage of fuel elements exceeding the maximum design limit.
79. Accident management - actions aimed to prevent development of design basis accidents into beyond design basis ones and to mitigate the consequences of beyond design basis accidents.
80. Management for safety purposes - activities performed by the administrative system of the NPP operating organization. This system integrates all control elements in such a way that any processes assuring compliance with the NPP safety requirements are established and implemented with due regard for other requirements particularly economic requirements, requirements for the management, personnel, occupational safety, environmental protection, accounting and control of nuclear materials, physical security and quality so that these requirements and demands would not affect the NPP safety adversely.
81. Control safety systems (components) - systems (components) intended to initiate actions of safety systems and to assure control and monitoring thereof during performance of the prescribed functions.
82. Normal operation control systems (components) - systems (components) intended to initiate actions of normal operation systems and to assure control and monitoring thereof during performance of the prescribed functions.
83. Emergency preparedness level - the prescribed preparedness level for the NPP personnel, the operating organization, agencies of the national system for emergency prevention and response, any other forces involved as well as any equipment used to protect the personnel and the public in case of an accident at the NPP.
84. Intervention level - parameters and characteristics defining the radiation situation and its development that in combination demand implementation of measures for protection of the personnel and the public.
85. NPP state severity levels - the set of postulated NPP states where each state is characterized by degree of damage to physical barriers in the way of radioactive substances and (or) ionizing radiation releases to the environment.
86. Safe operation conditions - the minimum requirements for quantity, characteristics, operability, scope, frequency and other conditions of maintenance, control and testing of safety-related systems (components) established in the NPP design when compliance with the safe operation limits and (or) safety criteria is assured.
87. Physical security of the NPP - activities in the area of nuclear energy use performed in order to prevent sabotage and theft in relation to nuclear installations, radiation sources, storage facilities, nuclear materials and radioactive substances including technical and administrative measures aimed to achieve the above-mentioned purposes.
88. Physical start-up - the stage of the NPP power unit commissioning including fueling of the reactor, achieving of the reactor criticality and performance of necessary tests at the power level when heat is removed from the reactor due to natural heat losses (dissipation).
89. Physical separation - usage of barriers or distance in order to prevent simultaneous exposure of several NPP systems (channels, components) to the effects of any internal and external impacts as well as propagation of effects from one NPP system (channel, component) to the others.
90. Safety function - particular aim and actions ensuring its achievement and intended to prevent accidents and (or) to mitigate their consequences.
91. Operation limits - the values of parameters and characteristics of the systems (components) and the entire NPP established in the NPP design for normal operation.
92. Operation conditions - conditions for the quantity, characteristics, operability and maintenance of systems (components) established in the NPP design and required for operation without any deviations from the operation limits.
93. Operating personnel of the NPP - the NPP workers performing its operation.
94. NPP operation (operation) - all activities intended to achieve the aim of the NPP construction in a safe way particularly power operation, start-up, shutdown, testing, maintenance, repair, refueling, inspection in the course of operation and any other associated activities.
95. Abnormal operation - the NPP operation with deviations from the operation limits or conditions but without any exceedance of the safe operation limits or conditions.
96. NPP operating organization (operating organization) - the organization established in accordance with the legislation of the Russian Federation and recognized in accordance with the procedure and under the terms and conditions stipulated by the Government of the Russian Federation and the relevant nuclear energy usage controlling agency as suitable for operation of the NPP and performance of the activities for the NPP siting, design, construction, operation and decommissioning as well as activities for handling of nuclear materials and radioactive substances with its own efforts or through engagement of any other organizations. In order to perform these types of activities the operating organization shall have permits (licenses) issued by state safety regulation authorities and granting the right to perform works in the area of nuclear energy use.
97. NPP components (components) - civil structures, equipment, instrumentation, pipelines, measuring, monitoring, control and automation devices, cables and other items assuring performance of the prescribed functions independently or within systems and considered in the NPP design as structural units for the purposes of reliability and safety analyses.
98. Power start-up - the stage of the NPP Power unit commissioning from completion of the physical start-up to commencement of power generation and delivery to consumers.
99. Nuclear accident - an accident accompanied by damage of fuel elements exceeding the established safe operation limits or an accident without FE damage caused by:
any disturbance in the chain fission reaction monitoring and control;
criticality occurrence in the course of refueling, transportation and storage of nuclear fuel.
100. Nuclear hazardous works - works with the safety-related NPP systems or components (including testing, shutdown for maintenance and commissioning) not prescribed on the process regulations for the NPP power unit operation and operation manuals as well as any other works included by the operating organization into the list of nuclear hazardous works on the basis of operation experience particularly subsequent to investigation of any NPP operational occurrences, with due regard for design and engineering documentation, because of the necessity to define specific requirements for these works not stated in the NPP power unit operation and operation manuals.
Only the works that may cause a nuclear accident in case of any deviations from the established procedure for their performance shall be classified as nuclear hazardous works.