Circular No. 05/2020/TT-BKHCN on nuclear safety for research nuclear reactor facilities

CIRCULAR

Regulations on nuclear safety for research nuclear reactor facilities

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Pursuant to the Atomic Energy Law dated June 3, 2008;

Pursuant to Decree No. 95/2017/NĐ-CP dated August 16, 2017, of the Government stipulating the functions, tasks, powers, and organizational structure of the Ministry of Science and Technology;

At the proposal of the Director of the Radiation and Nuclear Safety Administration and the Head of the Legal Department;

The Minister of Science and Technology issues this Circular to regulate nuclear safety for research nuclear reactor facilities.

PART I

GENERAL PROVISIONS

Article 1. Scope of Regulation

This Circular stipulates the requirements for nuclear safety in design, construction, trial operation, operation, and decommissioning of research nuclear reactor facilities (hereinafter referred to as "research nuclear reactors").

Article 2. Applicability

1. Investors and agencies and organizations implementing the selection of site, design, construction, trial operation, operation, and decommissioning of research nuclear reactor facilities.

2. Agencies and organizations implementing safety assessment, approval of site, approval of investment project, issuance of construction permit, issuance of trial operation permit, issuance of operation permit, and issuance of decommissioning permit for research nuclear reactor facilities.

Article 3. Explanation of Terms

In this Circular, the following terms are understood as follows:

1. A research nuclear reactor facility is a nuclear facility with a reactor used to produce neutron beams and radiation beams for research purposes and other purposes, including the reactor along with accompanying systems and equipment and related administrative-technical areas located at the same site.

2. Operating limits are ranges of values of parameters and characteristics of systems, components, and the overall research nuclear reactor facility determined in the design for normal operation.

3. Operating conditions are the quantity, characteristics, operational capability, and technical maintenance conditions of systems and components to ensure the operation of the research nuclear reactor facility within operating limits.

4. Safety operating limits are ranges of technological parameter values determined in the design such that when the research nuclear reactor facility operates outside these ranges, it may lead to an incident.

5. Safety operating conditions are the quantity, characteristics, operational capability, and technical maintenance conditions of important safety systems and components to ensure the operation of the research nuclear reactor facility within safety operating limits.

6. Design limits are ranges of values of parameters and characteristics of systems, components, and the overall research nuclear reactor facility determined in the design for normal operation, operational situations, and incidents.

7. Normal operation is when the research nuclear reactor facility operates within operating limits and conditions.

8. Operational situation is when the research nuclear reactor facility operates outside operating limits and conditions but does not lead to an incident.

9. Near-accident situation is when the research nuclear reactor facility operates outside safety operating limits and conditions but has not yet resulted in an accident.

10. Single failure is a failure leading to the loss of the ability to perform a safety function of a system or component, including secondary failures that accompany it.

11. Redundancy principle is the design of multiple systems and components capable of replacing each other to independently perform the same safety function.

12. Diversity principle is the design of multiple systems and components with different characteristics to perform the same defined safety function, thereby minimizing the likelihood of common cause failures.

13. Self-safety principle is the principle that when a failure occurs in a system or component, that system or component must still be able to perform its safety functions according to the design without activating protective actions through the safety control system.

14. Single-failure-proof principle is the principle applied to safety systems so that even if a single failure occurs, the system must still be able to perform its safety function.

15. Initiating event is an event leading to an operational situation, near-accident situation, or accident.

16. Accident is a condition where the research nuclear reactor facility operates outside safety operating limits and conditions, causing radioactive material leakage and dispersion beyond the boundaries of physical protection layers. Each accident is characterized by the initiating event, progression, and consequences of the accident.

17. Designed accident is a hypothetical accident considered in the design of the research nuclear reactor facility, ensuring that the consequences are controlled below the limit for that accident.

18. Beyond-design accident is a hypothetical accident with more severe accident conditions than those considered in the design.

19. Operational systems and components are systems and components used for normal operation.

20. Safety systems and components are systems and components used to perform safety functions.

21. Important safety systems and components include: safety systems and components; operational systems and components whose failure would lead to a near-accident situation or reduce the ability to mitigate a near-accident situation and could lead to an accident.

22. Active systems and components are systems and components whose function implementation depends on the normal operation of other systems and components.

23. Passive systems and components are systems and components whose function implementation does not depend on external supply or support.

24. Maximum allowable emergency release is the amount of radioactive material allowed to be released into the environment in the case of a beyond-design accident while ensuring that the dose received by the public inside and outside the emergency planning zone does not exceed the specified limit and does not require decisions to implement protective actions for the public (taking into account the most extreme weather conditions).

25. Site of the research nuclear reactor facility is the geographic area where the research nuclear reactor facility is located within the protected area.

26. Research nuclear reactor facility area is the geographic area containing the research nuclear reactor facility where phenomena, processes, and factors caused by natural or human activities can affect the safety of the research nuclear reactor facility.

Physical protection is the implementation of technical-administrative measures and security personnel actions to prevent sabotage or theft of nuclear materials, radioactive substances, and radioactive waste.

Chapter II

SAFETY REQUIREMENTS

Section 1

GENERAL SAFETY REQUIREMENTS

Article 4. Requirements for safety objectives

1. In normal operation, operational situations, or in case of incidents occurring within the design, the radiation dose to radiation workers and the public, and the amount of radioactive material released into the environment must not exceed the determined limit values.

2. In case of incidents outside the design, the radiation impact on radiation workers, the public, and the environment must be minimized.

Article 5. Requirements for depth protection

1. Depth protection includes the use of physical protective layers and technical-administrative measures to protect radiation workers, the public, and the environment from radiation effects emanating from the nuclear power plant facility.

2. Justification for implementing depth protection for the nuclear power plant facility must be established.

3. Technical-administrative measures must be verified through operational experience or testing and must comply with legal provisions regarding the design, construction, trial operation, operation, and decommissioning of the nuclear power plant facility.

4. Technical-administrative measures include five levels specified in Appendix I issued together with this Circular.

Article 6. Requirements for quality assurance

1. A quality assurance process must be established and implemented for all activities that can affect the safety of the nuclear power plant facility.

2. The quality assurance of organizations performing work and providing services to the operating organization must be monitored.

Article 7. Requirements for safety culture

1. Safety culture encompasses the overall perspective and behavior of organizations and individuals, prioritizing the safety of people and the environment from radiation effects.

2. The operating organization and organizations performing work and providing services must establish and maintain a safety culture through:

a) Recruitment, training, and instruction for employees involved in work affecting safety.

b) Clearly defining the responsibilities of managers and employees.

c) Establishing and adhering to work procedure guidelines and operational instructions; periodically updating these documents, taking into account operational experience.

Section 2

REQUIREMENTS FOR SAFETY IN DESIGN, CONSTRUCTION, TRIAL OPERATION,
OPERATION AND DECOMMISSIONING OF THE NUCLEAR POWER PLANT FACILITY

Article 8. Design Principles

1. Prioritize the use of passive systems or components with inherent safety characteristics (safety features based on feedback effects, processes, and natural properties).

2. Ensure the capability for direct and full system inspection of critical safety systems according to design parameters during trial operation, after repairs, and regular inspections throughout the life cycle of the nuclear power plant facility. If the design of the nuclear power plant facility does not allow for direct and full system inspection, ensure indirect and partial inspection capabilities of critical safety systems at specific frequencies.

3. Ensure the inspection and maintenance of critical safety systems during operation in accordance with safe operating limits and conditions; justification for the frequency and duration of inspection and maintenance must be established.

4. Consider and establish justification for measures to protect systems and components from common cause failures.

5. Implement technical solutions to prevent and mitigate consequences of human errors, including those during maintenance of critical safety systems.

Article 9. Elements in Design

The basic design of nuclear power plants must specify:

1. Physical-neutron characteristics, thermal-hydraulic characteristics, and other important safety characteristics.

2. Conditions and frequency of checking the conformity of physical-neutron characteristics with the design.

3. Operating modes, operating limits and conditions, and safe operating limits and conditions.

4. List of hazardous tasks related to nuclear activities and measures to ensure nuclear safety when performing such tasks.

5. Reliability indices of important safety systems and components belonging to Safety Classes I, II, and III as stipulated in Appendix III of this Circular.

6. List of construction structures, equipment, automatic devices, and other systems and components that must be certified according to regulations.

7. Classification of fire and explosion safety for areas within the nuclear power plant site.

8. Conditions, scope, frequency of inspection, and technical maintenance for important safety systems.

9. Activation conditions for safety systems; external impact levels requiring reactor shutdown and bringing the reactor to subcritical state.

10. List of design and beyond-design initiating events; probability assessment of accidents; accident scenarios.

11. Maximum allowable probability of large-scale emergency releases from the nuclear power plant site.

12. Dose constraint level, taking into account the specific characteristics of the nuclear power plant site area.

13. Operational life of the nuclear power plant site, equipment lifespan, and replacement criteria.

Article 10. Items in Design

The design of the nuclear power plant site must include all items specified in Appendix II of this Circular. In cases where the design does not include all these items, an argumentation must be developed to prove that the absence of those items will not affect the safety of the nuclear power plant site.

Article 11. Classification and Grading of Safety for Systems and Components

1. The design of the nuclear power plant site must classify and grade safety for systems and components in accordance with safety requirements.

2. Systems and components of the nuclear power plant site are classified and graded for safety according to the provisions in Appendix III of this Circular.

Article 12. Safety Requirements for System Designs

Safety requirements for system designs of the nuclear power plant site are stipulated in Appendix IV of this Circular.

Article 13. Safety Requirements for Construction of the Nuclear Power Plant Site

1. Construction of the nuclear power plant site, manufacturing, and installation of systems and equipment must comply with detailed design specifications.

2. Construction structures, equipment, tools, and automatic devices (including physical protection technical means) must have certification documents (if they belong to the category requiring mandatory certification).

3. Quality control, work acceptance, and system component acceptance must comply with detailed design specifications and quality assurance procedures.

Article 14. Safety Requirements for Trial Operation of the Nuclear Power Plant Site

1. Technical and administrative measures must be implemented to verify the conformity of achieved technical characteristics with the design.

2. The following tasks must be carried out:

a) Establish radiation safety guidelines and set control levels;

b) Issue and periodically update technical documentation of the nuclear power plant site;

c) Develop and implement dose reduction measures and personnel exposure reduction measures, and periodically update dose records of radiation workers;

d) Organize physical protection; inventory and control of nuclear materials, radioactive substances, and radioactive waste.

3. A trial operation program must be established with the following contents:

a) Main stages of each task during trial operation;

b) Initial status of the nuclear power plant site before each stage of each task during trial operation;

c) Content and requirements for documentation at each stage of trial operation.

4. Trial operation must include calibration start-up, physical start-up, and power start-up phases.

5. During the calibration start-up phase, the operational capability and conformity with design of each system and the overall system under mutual influence must be checked.

6. During the physical start-up phase (including fuel loading into the core), the conformity of physical-neutron characteristics with the design must be checked.

7. During the power start-up phase, the following must be conducted:

a) Survey the impact of power and temperature on physical-neutron characteristics measured during the physical start-up phase;

b) Study the characteristics of experimental channels and irradiation channels, including neutron flux distribution at channel outlets in the reflector region and within the core;

c) Measure radiation levels at the nuclear power plant site location.

8. During power start-up, the reactor must be brought up to design parameters in multiple stages with defined power levels and time intervals.

9. All adjustments made after trial operation must be incorporated into design-technical documents, Safety Analysis Report, technology documents, and nuclear power plant site operation documents.

Article 15. Requirements for Operating a Nuclear Power Plant Facility

The operating organization must perform the following tasks:

1. Establish an organizational structure with the following components:

a) The head of the nuclear power plant facility (responsible directly for the safety of the nuclear power plant facility);

b) Operating staff;

c) Maintenance, repair, and replacement staff for equipment and technical means;

d) Staff monitoring the establishment and implementation of quality assurance procedures;

đ) Calibration unit for measuring devices;

e) Safety control unit for radiation and nuclear safety, industrial safety, and fire and explosion safety;

g) Security unit ensuring the operation of physical protection systems.

2. Ensure that there is a team of employees with appropriate professional qualifications and training suitable for their assigned functions and responsibilities.

3. Develop internal regulations, assign responsibilities and authorities for leadership positions, and specify professional requirements for employees.

4. Develop an employee training program, including: training curriculum, internships, periodic examinations, practical skills training for controlling the nuclear power plant facility and operating experimental equipment, training for operational scenarios, near-accident situations, and accidents; safety culture training.

5. Prepare a safety analysis report, operating guidelines, and technical documentation for the nuclear power plant facility, clearly stating design limits and safe operating conditions.

6. Ensure the implementation of the following procedures:

a) Fuel loading and bringing the reactor to critical state;

b) Fuel shuffling;

c) Startup, power level changes, and power operation;

d) Control rod calibration;

đ) Measuring and monitoring reactivity reserve levels;

e) Neutron flux distribution control channel calibration;

g) Determining the power of the nuclear power plant facility and calibrating the ionization chamber of the control system;

h) Actions of staff upon receiving warning signals;

i) Actions of staff upon activation of the protective system;

k) Planned shutdown of the reactor and deactivation of equipment;

l) Handling nuclear materials;

m) Handling radioactive substances and radioactive waste;

n) Other procedures in cases involving dangerous work related to radiation and nuclear activities.

7. Develop usage guidelines for systems, technological equipment, and experimental equipment, including instructions for normal operation, operational scenarios, and procedures for handling both designed and undesignated accidents.

8. Develop procedures for storing and preserving operational records.

9. Archive design documents, manufacturing records for equipment, test reports and minutes, maintenance records for technical systems, and safety system repairs belonging to safety classes 1 and 2 throughout the lifecycle of the nuclear power plant facility.

10. Conduct investigations and research on near-accident situations and previously occurred accidents; develop and implement measures to prevent the recurrence of similar near-accidents and accidents.

11. Develop and implement procedures for collecting, processing, analyzing, systematizing, and archiving information about operational situations of the nuclear power plant facility during its operation and when transferring it to another organization.

12. Implement internal controls for safety assurance and physical protection, and include inspection results in the current safety status report of the nuclear power plant facility.

13. Ensure that startup, power operation, temporary shutdown, long-term shutdown, and permanent shutdown comply with the requirements specified in Appendix V of this Circular.

Article 16. Requirements for terminating operations at nuclear fuel cycle facilities

1. Prior to terminating operations at a nuclear fuel cycle facility, the following must be completed:

a) Removal of all nuclear materials from the site of the nuclear fuel cycle facility;

b) Installation of specialized equipment to ensure safety during dismantling, decontamination, and radioactive waste management;

c) Training of staff involved in activities related to the termination of operations at the nuclear fuel cycle facility.

2. When terminating operations at a nuclear fuel cycle facility, it must be ensured that:

a) The amount of radioactive waste is minimized;

b) Radiation dose exposure to radiation workers is reduced;

c) Radiation impact on the public is eliminated;

d) Radioactive waste entities are counted, controlled, and protected.

ChapterIII

IMPLEMENTING PROVISIONS

Article 17. Effective Date

1. This Circular takes effect from December 15, 2020.

2. During implementation, if there are any difficulties, agencies, organizations, and individuals shall promptly report them to the Ministry of Science and Technology for review and amendment.

Article 18. Transitional Provisions

Nuclear fuel cycle facilities that have been granted operating licenses prior to the effectiveness of this Circular must comply with the provisions of Articles 15 and 16 of this Circular during operation, when applying for license renewal, or requesting a license to terminate operations./.