Circular No. 28/2011/TT-BKHCN on nuclear safety requirements for the location of nuclear power plants

PART I

GENERAL PROVISIONS

Article 1. Scope of Regulation

These Circulars regulate nuclear safety requirements and surveys, evaluations to serve the approval of the site of nuclear power plants (hereinafter referred to as NPP).

Article 2. Applicability

These Circulars apply to project investors and agencies, organizations participating in surveys, evaluations, appraisals, and approvals of the NPP site; and related consulting organizations.

Article 3. Explanation of Terms

In this Circular, the following terms shall be understood as follows:

1. Design entity including conditions, processes, factors caused by natural or human activities that are clearly considered when designing the NPP, so that when such conditions, processes, and factors occur, the NPP's safety system can still operate according to design, and safety limits approved by competent authorities are maintained.

2. Adverse Conditions are conditions, processes, natural or human-caused factors that have the potential to cause incidents at the NPP.

3. Fault Movement is a tectonic fault capable of causing displacement on or near the surface of the ground.

4. Karst is a combination of geological processes and phenomena appearing on the surface or within the earth mainly due to chemical dissolution of rocks, resulting in cave voids, destroying and altering rock structure, state, groundwater mechanism, topography characteristics, hydrological network mechanism.

5. Design Incident is a condition, process, natural and artificial factor that has the potential to cause an incident that has been taken into account in the design.

Chapter II

GENERAL REQUIREMENTS FOR NUCLEAR SAFETY

FOR THE SITE OF NUCLEAR POWER PLANTS

Article 4. Principles in evaluating the site

1. The site is evaluated as suitable for constructing a NPP if it meets the following conditions simultaneously:

a) It has the ability to ensure safety for the NPP during normal operation as well as when a design incident occurs;

b) It has the ability to ensure that people and the environment are not adversely affected by radiation during normal operation as well as when a design incident occurs;

c) Minimizes harm to people and the environment in the event of an incident exceeding the level anticipated in the design (hereinafter referred to as an off-design incident).

2. When evaluating the NPP site, a comprehensive survey and study of the following factors and characteristics must be conducted:

a) Natural and human factors that may affect the safety of the NPP from outside;

b) Characteristics of the site and the environment related to the spread of radioactive emissions from the NPP that could harm people and the environment;

c) Population density, distribution, and characteristics of the area relevant to the implementation of emergency response measures.

3. In cases where the evaluation according to Clause 2 of this Article shows that the site has any of the following characteristics, the site shall not be accepted:

a) There is active fault movement;

b) There is potential for ground shaking due to earthquakes with maximum ground acceleration (PGA) reaching or exceeding 360 cm/s2, with a recurrence period of 10,000 years;

c) There is developing karst or karst creating sinkholes with diameters greater than 20 meters on the surface.

4. In cases where the evaluation according to Clause 2 of this Article shows that, in addition to the characteristics specified in Clause 3 of this Article, the site also has other adverse conditions that cannot be mitigated through design measures, protective solutions, or administrative regulations, then the site shall not be accepted.

Article 5. Survey and Research on Site Characteristics

1. Conduct surveys and research on the characteristics of the site, related factors, and determine their level of hazard according to the following provisions:

a) Survey and research on the characteristics of the site that may affect the safety of the nuclear power plant (NPP), including: earthquakes, surface fractures, volcanoes, meteorology, flooding, tsunamis, geotechnical aspects, human-induced factors, cooling water sources, and power supply for the NPP;

b) Collect historical data, records, and measurements regarding the frequency and severity of significant natural phenomena relevant to assessing the safety of the NPP site. For seismic, meteorological, and hydrological data, there must be measurement records not older than five years from the date of submitting the application for site approval, including at least twelve consecutive months of reliable, accurate, and complete data;

c) Forecast changes in characteristics that may affect the safety of the NPP over a period equal to or longer than the expected operational life of the NPP;

d) Survey and research on the frequency and determine the level of hazard of natural and man-made factors that may affect the safety of the NPP;

đ) Use appropriate methods to determine the level of hazard of factors that may affect the safety of the NPP. The method used must be advanced and proven suitable for the characteristics of the survey area;

e) Use specific data related to the site to determine the level of hazard. In cases where specific data related to the NPP site cannot be collected, data from other places with proven equivalent characteristics can be used;

g) When conducting surveys and research on the characteristics specified in point a of this clause, appropriate parameters and parameter values must be selected to serve the purpose of determining the level of hazard for NPP design;

h) The scope of the survey, research, and determination of the level of hazard of natural and man-made factors must be proven sufficiently large to cover all important characteristics for determining the level of hazard of phenomena and events, and be consistent with the specific method used.

2. When conducting surveys and research to select and evaluate sites, Vietnamese standards must be applied. Where Vietnamese standards are incomplete or inconsistent, foreign standards approved by competent authorities may be applied.

3. Activities and results of surveys and research must be documented for retention and submitted to the competent state authority when applying for NPP site approval.

Article 6. Impact of Nuclear Power Plants

1. Survey and research on environmental factors affecting the ability of radioactive material dispersion from the NPP, including air, surface water, and groundwater dispersion. The scope of the survey and research depends on the dispersion capability of radioactive materials during normal operation of the NPP as well as in case of accidents.

2. Determine the potential radiological impact on humans and the environment based on the facility design and the amount of radioactive material released during normal operation of the NPP as well as in case of accidents requiring emergency response plans.

3. Identify and assess direct and indirect radioactive dispersion pathways from the NPP, the range of areas where people and the environment may be harmed. Identification and assessment are based on regional characteristics, paying attention to biosphere features related to radionuclide accumulation and transport.

4. Evaluate the site in relation to the NPP facility design. The evaluation must provide sufficient basis to conclude that radiation doses caused by the plant to radiation workers and the public are limited to the lowest reasonably achievable levels, not exceeding legal limits.

Article 7. Population Characteristics and Emergency Response Plan

1. Study and evaluate the current and future population characteristics and distribution in areas potentially affected by radioactive material dispersion from the nuclear power plant. The study and evaluation must include land use, water usage assessments, and be related to specific features concerning the harmful radiation spread level.

2. Study and assess the possibility of establishing an emergency response zone around the nuclear power plant site based on the research and evaluation results stipulated in Clause 1 of this Article and relevant features for implementing the emergency response plan, ensuring that the radiation dose caused by the plant to the public does not exceed the limits set by law.

Article 8. Monitoring for Safety Assurance

Monitoring of factors and characteristics related to safety assurance for the nuclear power plant, people, and the environment shall be carried out throughout the life cycle of the plant, including tracking increases and distributions of the population.

Article 9. Quality Assurance and Inspection of Survey, Research, and Data Collection Activities

1. The project investor and related agencies and organizations, when conducting survey, research, and data collection activities for site assessment, must implement the following provisions:

a) Establish and implement a quality assurance program, particularly focusing on activities that may affect safety and the determination of design parameters.

b) Submit plans for conducting survey, research, and data collection activities related to nuclear safety requirements for the nuclear power plant site to the radiation and nuclear safety agency.

2. The radiation and nuclear safety agency is responsible for inspecting and supervising survey, research, and documentation activities related to nuclear safety requirements for the nuclear power plant site according to the law.

Chapter III

SURVEY AND ASSESSMENT OF NATURAL CONDITIONS AND HUMAN ACTIVITIES RELATED TO THE SITE

OF THE PERSON RELATED TO THE LOCATION

Article 10. Earthquakes, Surface Faulting, and Volcanoes

1. Assess the level of hazard posed by ground shaking due to earthquakes to the site, taking into account seismic characteristics and special conditions of the ground. Conduct reliability analysis of the assessment results.

2. Study and evaluate evidence of active faulting, volcanic activity potential, and their hazards to the safety of the nuclear power plant. The assessment is conducted using detailed survey and research methods to make reasonable decisions.

Article 11. Meteorology

1. Survey and research meteorological parameters and extreme weather phenomena that can impact the safety of the nuclear power plant, including lightning, tornadoes, typhoons, and other local weather events.

2. The survey and research results must be comprehensive and appropriate for nuclear power plant design purposes, including assessing the probability of occurrence of extreme weather phenomena with parameters exceeding design specifications.

Article 12. Flooding

Assess the flooding potential at the site according to the following provisions:

1. Identify causes resulting from one or a combination of natural phenomena, including heavy rain, high tides, storm surges, sea waves, floods, and other phenomena. In cases where flooding could affect the safety of the nuclear power plant, necessary meteorological and hydrological data must be collected, monitored, and analyzed, including historical data analysis. For historical data, the relevance and reliability of the data for site assessment must be considered.

2. Analyze data related to the structure of upstream water regulation systems contributing to flooding potential.

3. Develop appropriate meteorological and hydrological models considering limitations in data accuracy and quantity, data collection time constraints, and past changes in related characteristics in the area.

Article 13. Tsunamis

1. Conduct a comprehensive assessment of the relevant area to determine the likelihood of tsunamis affecting the safety of nuclear power plants. In cases where there is a possibility of tsunamis impacting the safety of nuclear power plants, collect, record, analyze necessary seismic and tectonic data, including historical and prehistoric data. For historical and prehistoric data, consider their relevance and reliability for site evaluation.

2. Based on collected data and comparing the area with fully studied regions having similar characteristics regarding tsunami phenomena, assess the frequency of occurrence, destructive force, and height of tsunamis to determine the level of hazard, taking into account coastal features that increase the level of hazard.

3. Develop appropriate tsunami impact models considering limitations in data accuracy and quantity, time constraints for data collection, and evaluate the potential impact on nuclear power plant safety under different scenarios.

Article 14. Geotechnical Factors

1. Assess the risk of slope instability and landslides affecting the safety of nuclear power plants. If there is a risk of slope instability impacting the safety of nuclear power plants, determine the level of hazard using specific parameters and ground motion values of the region.

2. Evaluate the potential for surface subsidence and uplift caused by natural and human factors such as caves, karst formations, mines, wells, and oil wells based on geological maps and suitable data.

3. Assess the potential for soil liquefaction at the site using soil parameters and ground motion values. Utilize appropriate geotechnical survey methods and analyses to determine the level of hazard posed by soil liquefaction to nuclear power plants.

4. The geotechnical characteristics of the soil, groundwater conditions, and chemical properties must be investigated and studied. Soil layers at the site must be identified and described in a manner suitable for design purposes. The stability of foundations under static and seismic loads must be evaluated.

Article 15. Human-Induced Factors

1. Assess the risk of aircraft crashes at the nuclear power plant site and the level of hazard, considering flight frequencies and characteristics of current and future aircraft. If there is a risk of aircraft crashes at the site, determine the level of hazard to the nuclear power plant.

2. Identify activities within the relevant area involving the handling, storage, and transportation of chemicals capable of causing explosions or generating flammable gases, and determine the level of hazard from chemical explosions, including pressure effects and toxicity, considering distances to the site.

Article 16. Cooling Water Sources and Power Supply for Nuclear Power Plants

1. Assess site parameters related to cooling water supply for nuclear power plants, including:

a) Air temperature and humidity;

b) Water temperature;

c) Water source with data on flow rate, minimum water volume, duration when the water source is at its minimum volume, taking into account the possibility of structural water regulation failures.

2. Determine causes of reduction or changes in the quality of cooling water supplied to nuclear power plants due to natural or human activities such as river flow alteration or blockage, depletion of reservoirs, excessive amounts of contaminants or marine life, oil spills, and fires.

3. Identify power sources for structures, systems, and critical components essential for the safety of nuclear power plants.

Chapter IV

SURVEY AND ASSESSMENT OF RADIATION DISPERSION CAPABILITY FROM NUCLEAR POWER PLANTS AFFECTING THE PUBLIC

FROM NUCLEAR POWER PLANTS IMPACTING THE PUBLIC

Article 17. Release of Radioactivity into the Atmosphere

1. Meteorological surveys and studies, including topography, basic meteorological phenomena and parameters such as heavy rainfall, humidity, wind speed and direction, air temperature, atmospheric stability and turbulence.

2. Implement a meteorological monitoring program at relevant locations and areas to assess the release of radioactivity into the atmosphere. Use monitoring equipment capable of recording meteorological parameters at appropriate heights and positions. The determination of monitoring areas and placement of monitoring equipment depends on the characteristics of the terrain and meteorology. In addition to monitoring data, data from other meteorological sources must be collected.

3. Evaluate the release of radioactivity into the atmosphere based on collected data and suitable dispersion models. Dispersion models must account for the geographical features of the relevant location and area affecting the release of radioactivity into the atmosphere, and the characteristics of the nuclear facility as shown in the basic design.

Article 18. Release of Radioactivity into Surface Water

1. Survey and study surface water characteristics in the relevant area related to the potential release of radioactivity into surface water, including natural and artificial water sources, major structures for water control, installation locations of water intake structures, and surface water usage in the area.

2. Conduct a survey and research program on surface water to determine the dilution and diffusion capacity of water sources, sediment and biological accumulation capacity, mechanisms of radionuclide transport in the hydrosphere, and radiation exposure pathways.

3. Assess the potential impact of radiated surface water on the population based on collected data and suitable dispersion models.

Article 19. Release of Radioactivity into Groundwater

1. Survey and study groundwater characteristics in the relevant area related to the potential release of radioactivity into groundwater, including water source characteristics, their interaction with surface water, and groundwater usage in the area.

2. Implement a survey and research program to analyze groundwater characteristics to evaluate radionuclide transport mechanisms. This program must include surveys and studies of soil characteristics, water, physical and chemical properties of materials in the soil related to radionuclide accumulation and transport mechanisms in groundwater and radiation exposure pathways.

3. Assess the potential impact of radiated groundwater on the population based on collected data and suitable dispersion models.

Article 20. Population Distribution and Radiation Background

1. Determine population distribution data based on the latest census and extrapolation to obtain current and future data for areas potentially affected by radioactive releases. If reliable data is insufficient, additional surveys and studies must be conducted. Data must be analyzed to determine population distribution in relation to directions and distances from the nuclear facility. Evaluate the potential impact of radiation on the population under normal emissions and accident conditions, including severe accidents, taking into account site-specific parameters.

2. Assess the radiation background in the atmosphere, hydrosphere, lithosphere, and biota in the area to serve as a basis for determining the future radiation impact of the nuclear facility.

Article 21. Radiation Dose Limits for the Public

The selected location must ensure:

1. In the case of normal operation of the nuclear power plant, the radiation dose caused by the plant to the public does not exceed the limit prescribed by law.

2. In the event of an accident, the emergency response plan can be implemented so that the radiation dose caused by the plant to the public does not exceed the limit prescribed by law.

Chapter V

IMPLEMENTING PROVISIONS

Article 22. Effectiveness

1. This Circular takes effect from December 15, 2011.

2. During implementation, if there are any difficulties, it is requested that agencies, organizations, and individuals promptly report to the Ministry of Science and Technology for review and amendment./.