Thông tư 05/2020/TT-BKHCN

CIRCULAR

REGULATIONS ON NUCLEAR SAFETY FOR RESEARCH REACTORS

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

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

At request of Director General of Vietnam Agency for Radiation and Nuclear Safety and Director of Department of Legal Affairs;

Minister of Science and Technology promulgates Circular on nuclear safety for research reactors.

Chapter I

GENERAL PROVISIONS

Article 1. Scope

This circular prescribes requirements for nuclear safety in designing, constructing, operating experimentally, operating and terminating operations of research reactors.

Article 2. Regulated entities

1. Project developers, agencies and organizations shall select locations, design, construct, operate experimentally, operate and terminate operations of research reactors.

2. Agencies and organizations shall appraise safety, approve locations, approval investment projects, license construction, permit experimental operations, permit operations and permit termination of research reactors.

Article 3. Term interpretation

In this Circular, terms below are construed as follows:

1. “research reactor” refers to a nuclear reactor specialized in creating neutron beams and radiation beams for research purposes and other purposes, including reactor and attached systems, equipment and relevant administrative – technical sections situated in the same area.

2. “operational threshold” refers to parameters and characteristics of systems, components and whole units of research reactors determined in design intended for regular operation.

3. “operational requirements” refer to requirements in term of quantity, characteristics, operational capability and technical maintenance of the system and components to guarantee operation of research reactors within operational threshold.

4. “safe operational threshold” refers to technological parameters determined in design beyond which operating research reactors might be met with accidents.

5. “safe operational requirements” refer to requirements in term of quantity, characteristics, operational capability and technical maintenance of important system and components regarding safety to guarantee operation of research reactors within safe operational threshold.

6. “design threshold” refers to parameters and characteristics of systems, components and whole units of research reactors determined in design intended for regular operation, operating and accident scenarios.

7. “regular operation” refers to the situation in which a research reactor operates within operational threshold and operational requirements.

8. “operating scenario” refers to the situation in which a research reactor operates beyond operational threshold and operational requirements without being met with accidents.

9. “close call” refers to the situation in which a research reactor operates beyond safe operational threshold and safe operational requirements without being met with accidents.

10. “single failure” refers to a failure that leads to inability to adopt safety measures of a system or component; including accompanying secondary failure.

11. “backup principles” refer to designing multiple systems and components that can replace one another to independently perform the same functions safely.  

12. “diversified principles” refer to designing multiple systems and components with different properties to perform the same specific functions safely in order to minimize possibilities of errors originating from the same causes.

13. “fail-safe principle” refer to the principle in which if a system or component encounters an error, that system or component must still be able to adopt safety measures by design without activating protective measures via safety control systems.

14. “single failure preventive principles” refer to principles applied to safety systems to enable these systems to perform safety functions in case of single failures.

15. “initiating events” refer to events that lead to operating scenarios, close calls or accidents.

16. “accidents” refer to cases in which research reactors operate beyond safe operational threshold and safe operational requirements causing leak or dispersion of radioactive materials outside of physical barriers. Each incident is characterized by initiating event, development and consequences.

17. “design-basis accidents” refer to presumptive accidents accounted for in fundamental design of research reactors and guaranteed for damage control.

18. “beyond-design-basis accidents” refer to presumptive accidents and conditions for accidents more severe than design-basis accidents.

19. “operating systems and components” refer to systems and components employed for regular operation.

20. “safety systems and components” refer to systems and components employed to perform safety functions.

21. “important systems and components for safety” consist of: safety systems and components; operating systems and components which if fail will lead to close calls or reduce ability to rectify close calls and potentially cause accidents.

22. “active systems and components” refer to systems and components which rely on regular operation of other systems and components to perform design functions. 

23. “passive systems and components” refer to systems and components which do not rely on external provision or support to perform functions.

24. “maximum waste discharge allowed” refer to amounts of radionuclide permitted to be discharged to the environment in case of beyond-design-basis accidents while still ensuring that exposure to the public inside or outside of area subject to emergency protection plans does not exceed limits prescribed by the law and public protection measures are not necessary (taking into account the most extreme weather conditions).

25. “research reactor location” refers to geographical location of a research reactor within protection perimeter.

26. “research reactor vicinity” refers to an area with a research reactor where natural or artificial phenomena, processes or factors may affect safety of the research reactor.

27. “entity protection” refers to adoption of administrative – technical measures and action of security employees to prevent vandalism or appropriation of nuclear materials, radioactive substances and radioactive wastes.

Chapter II

SAFETY REQUIREMENTS

Section 1. GENERAL SAFETY REQUIREMENTS

Article 4. Requirements for safety objectives

1. In regular operation, operating scenarios or design-basis accidents, exposure of radiation workers and general public, amount of radioactive substances discharged into the environment must not exceed maximum value.

2. In case of beyond-design-basis accidents, impact of exposure on radiation workers, the general public and environment must be minimized.

Article 5. Requirements for vertical protection

1. Vertical protection includes the use of physical barriers and administrative – technical measures to protect radiation workers, the general public and environment from radiation impact from research reactors.

2. Develop facts for vertical protection for research reactors.

3. Administrative – technical measures must be tested via operational experience or test operation and must conform to regulations and law on design, construction, experimental operation, operation and termination of operation of research reactors.

4. Administrative – technical measures consist of 5 levels accord to Annex I attached to this Circular.

Article 6. Requirements for quality assurance

1. Develop and adopt procedures for quality assurance for all operations that may affect safety of research reactors.

2. Supervise quality assurance of organizations perform tasks and providing services for operating organizations.

Article 7. Requirements for safety culture

1. Safety culture includes overall points of view and behaviors of organizations and individuals with the top priority of assuring safety for human and environment from radiation.

2. Operating organizations and organizations that perform tasks, provide services must develop and maintain safety culture via:

a) Recruiting, educating and training employees performing tasks that affect safety;

b) Clearly defining responsibilities of managers and employees;

c) Developing and conforming to manual for tasks and operation; periodically updating these documents taking into account operational experience.

Section 2. SAFETY REQUIREMENTS FOR DESIGN, CONSTRUCTION, EXPERIMENTAL OPERATION, OPERATION AND TERMINATION OF RESEARCH REACTORS

Article 8. Design principles

1. Prioritize using passive systems, components or systems, components with passive safety features (safety features that rely on feedback mechanisms, natural process and properties).

2. Ensure ability of physical and thorough examination of important systems for safety according to design specifications throughout experimental operation, after repair and regular examination during lifetime of research reactors.

In case design of research reactors does not allow physical and thorough examination, ensure ability of indirect examination and in stages for important systems for safety with specific frequency.

3. Guarantee technical examination and maintenance of important systems, components to safety in operation process conforming to safe operational requirements and threshold; develop facts regarding suitability of frequency and period of technical examination and maintenance.

4. Consider and develop facts for measures that protect the systems and components from errors originating from the same causes.

5. Develop technical solutions to prevent and minimize consequences of employee errors, including errors during maintenance process for important systems for safety.

Article 9. Factors in design

Design of research reactors must identify:

1. Physical – neuron, thermo-hydro properties and other important safety properties.

2. Requirements and frequency of testing conformity of physical – neuron properties to design.

3. Operation modes, operational threshold and requirements, safe operational threshold and requirements.

4. List of dangerous tasks related to nuclear and measures to ensure nuclear safety during implementation.

5. Credibility indicator of class 1, class 2, and class 3 important systems and components for safety according to Annex III under this Circular.

6. List of construction structures, equipment, automated vehicles and other systems, components that must be certified as per the law.

7. Classification in terms of fire safety in research reactor vicinity.

8. Requirements, scope and frequency of examination and technical maintenance for important systems for safety.

9. Requirements for activation of safety systems; level of external impact for deactivation of reactors, bringing reactors to subcritical state,

10. List of events initiating design-basis accidents and beyond-design-basis accidents; assessment of possibilities of incidents; incident scenarios.

11. Possibilities of maximum waste discharge allowed from research reactors.

12. Level of dose control, taking into account characteristics of research reactor vicinity.

13. Operation duration of research reactors, lifetime and requirements for equipment change.

Article 10. Items in design

Design of research reactors consists of all items regulated under Annex II attached to this Circular. In case design does not consist of all items stated above, develop facts proving that the lack of such items do not affect safety of research reactors.

Article 11. Classification and safety ranking for systems and components

1. Design of research reactors must classify and rank systems and components for safety conforming to safety requirements.

2. Systems and components of research reactors shall be classified and ranked for safety according to Annex III under this Circular.

Article 12. Safety requirements for system design

Safety requirements for design of systems of research reactors are prescribed under Annex IV of this Circular.

Article 13. Safety requirements for construction of research reactors

1. Construction of research reactors, production and installation of systems and components must conform to detail design.

2. Construction structures, equipment, tools and automated vehicles (including technical vehicles for protection of entity) must have license (if required).

3. Quality control, acceptance inspection for tasks, systems, components and equipment must conform to detail design and quality assurance procedures.

Article 14. Safety requirements for experimental operation of research reactors

1. Adopt administrative – technical measures to verify conformity of achieved technical properties compared to the design.

2. Perform following tasks:

a) Develop guidelines for radiation safety assurance and establish control levels;

b) Issue and periodically update technical dossiers of research reactors;

c) Prepare and periodically update dose documents of radiation workers; develop and adopt measures to reduce dose and exposed individuals;

d) Organize entity protection; list and control nuclear materials, radioactive substances and wastes.

3. Develop experimental operation programs for following categories:

a) Primary stages of each task during experimental operation;

b) Initial status of research reactors prior to each stage of each task in experimental operation;

c) Contents and requirements for documents in each stage of experimental operation.

4. Experimental operation must consist of following stages: initiation calibration, physical initiation and energy initiation.

5. During initiation calibration, examine ability to operate and conformity to design of each system and all systems as a whole in case of back and forth interaction.

6. During physical initiation (including fueling reactor core), examine conformity of physical – neuron properties compared to design.

7. During energy initiation:

a) Survey influence of capacity and temperature on each physical – neuron property measured during physical initiation phase;

b) Research characteristics of experiment channels and irradiation channels, including neutron flux distribution in exits of channels in reflectors and channels in reactor cores;

c) Measure radiation at research reactor vicinity.

8. During energy initiation, bringing reactors to nominal specifications by design must be implemented in stages with defined levels of capacity and period.

9. All adjustments implemented after experimental operation must be included in design – technical dossiers, safety analysis reports, technical documents and documents on operation of research reactors.

Article 15. Requirements for operation of research reactors

Operating organizations must perform following tasks:

1. Develop organizational structure with following compositions:

a) Heads of research reactors (directly responsible for safety of research reactors);

b) Operating employees;

c) Employees for maintenance, repair and replacement of equipment and technical vehicles;

d) Employees for supervising preparation and implementation of quality assurance procedures;

dd) Measuring instrument calibration departments;

e) Control department for radiation, nuclear safety, industrial safety and fire safety;

g) Security department ensuring operation of entity protection system.

2. Ensure that employees are accordingly trained to suit assigned tasks and functions.

3. Develop internal regulations, assign responsibilities and rights for heads, position and specialized requirements for employees.

4. Develop procedures for training operating employees, including: training, internship programs, periodical examination, training for operation of research reactors and experiment equipment, training for behaviors in case of operating scenarios, close calls and accidents; training for safety culture.

5. Prepare safety analysis reports, operation guidelines and technology documents of research reactors which specify design threshold and safe operational requirements.

6. Ensure following procedures:

a) Fueling and bringing reactors to criticality;

b) Replacing fuel;

c) Initiating, changing capacity and operating; 

d) Calibrating control bar;

dd) Measuring and monitoring reserve level of radioactive level;

e) Calibrating channels controlling neutron flux distribution;

g) Determining capacity of research reactors and calibrating ionization chambers of control systems;

h) Actions of employees in case of warnings;

i) Actions of employees in case of activation of protection systems;

k) Suspending reactors according to the plans and shutting all equipment down;

l) Disposing nuclear materials;

m) Disposing radioactive substances and wastes;

n) Other procedures in case of performing dangerous tasks related to radiation and nuclear.

7. Develop and provide guidelines for using systems, technology equipment and experiment equipment which guide interaction in case of regular operation, operating scenarios and procedures in case of design-basis accidents and beyond-design-basis accident.

8. Develop procedures for storing and preserving operation documents.

9. Store design documents, equipment manufacturing documents, experiment records and reports, technical maintenance, class 1 and class 2 safety system and important system for safety repair documents throughout lifetime of research reactors.

10. Conduct investigations and research close calls and incidents that have occurred; develop and adopt measures to prevent repetition of similar close calls and accidents.

11. Develop and adopt procedures for collecting, processing, analyzing, systemizing and storing information on operating scenarios of research reactors during operation process and when transferring research reactors to other organizations.

12. Perform internal control to guarantee safety, entity protection and include examination results in safety status reports of research reactors.

13. Ensure that initiation and operation, reactor suspension, long-term reactor suspension, permanent reactor shutdown comply with Annex V under this Circular.

Article 16. Requirements for termination of operation of research reactors

1. Before terminating operation, research reactors must:

a) Transport all nuclear materials out of research reactor vicinity;

b) Furnish specialized equipment to ensure safety in unloading, decontaminating radiation and disposing radioactive wastes;

c) Train employees to perform tasks related to termination of operation of research reactors.

2. When terminating operation of research reactors:

a) Minimize radioactive wastes;

b) Minimize exposure of radiation workers;

c) Eliminate impact of radiation on the general public;

d) List, control and perform entity protection for radioactive wastes.

Chapter III

IMPLEMENTATION

Article 17. Entry into force

1. This Circular comes into force from December 15, 2020.

2. Difficulties that arise during the implementation of this Circular should be reported to the Ministry in writing for consideration.

Article 18. Transition clauses

Facilities permitted to operate research reactors before the effective date of this Circular must adopt Article 15 and Article 16 of this Circular during operation process when applying for extension of operation permit or applying for permission to terminate operation./.