Circular No. 19/2012/TT-BKHCN on radiation control and safety assurance in occupational and public irradiation

CIRCULAR

Section 1

GENERAL PROVISIONS

Article 1. Scope of Regulation and Applicability

1. These Circulars set forth requirements for radiation control and safety guarantees in occupational and public irradiation.

2. These Circulars apply to the following agencies, organizations, and individuals:

a) Organizations and individuals conducting radiation work;

b) Organizations and individuals managing and participating in response to radiation incidents, nuclear radiation incidents;

c) Organizations and individuals conducting work at locations where the concentration of Radon-222 gas exceeds 1,000 Becquerels per cubic meter (1,000 Bq/m³);

d) State agencies with the function of reviewing and inspecting radiation and nuclear safety;

đ) Organizations and individuals providing personal dosimetry services;

e) Organizations and individuals exporting, importing, collecting metal waste, and recycling metals.

Article 2. Interpretation of Terms

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

1. Occupational Irradiation means irradiation of individuals occurring during the conduct of radiation work, response to radiation incidents, working at locations where the concentration of Radon-222 gas exceeds 1,000 Becquerels per cubic meter (1,000 Bq/m³), or conducting reviews and inspections at facilities that conduct radiation work, excluding excluded irradiation (such as K-40 in the human body, cosmic rays on the ground...) and irradiation from exempted radiation sources and medical irradiation. Occupational irradiation includes external and internal irradiation.

2. Public Irradiation means irradiation of the public caused by permitted radiation work and irradiation in the event of a radiation incident, nuclear radiation incident, excluding occupational irradiation, medical irradiation, and irradiation from natural radiation background at the location.

3. Controlled Area means a place where protective measures and special safety regulations must be applied to control irradiation or prevent radioactive contamination from spreading under normal working conditions, preventing or limiting potential irradiation levels.

4. Supervisory Area means a place where irradiation conditions are always monitored even though there is no need for special protective measures and safety regulations like those required for controlled areas.

5. Potential Irradiation means uncertain but possible irradiation resulting from a radiation incident, nuclear radiation incident, an event, or a series of probabilistic events, including equipment failure and operational errors.

6. Dose Constraint is a factor used to determine the maximum dose from a radiation source or facility or radiation activity when calculating shielding design, taking into account optimization of radiation safety or potential future irradiation levels.

7. Investigation Level is the value of effective dose, dose rate, contamination level, or surface contamination level per unit area or volume, which if exceeded requires investigation to identify the cause and implement corrective measures.

8. Radiation Worker means employees working in controlled and supervisory areas.

9. Dose Limit is the value not to be exceeded for effective dose or equivalent dose to an individual exposed to controlled radiation work.

10. Residual Dose is the difference between the predicted dose and the avoidable dose after applying certain intervention measures.

11. Predicted Dose is the dose that could be received if a radiation incident, nuclear incident occurs without applying any intervention measures.

12. Avoidable Dose is the dose that can be reduced by applying intervention measures.

Section 2

REQUIREMENTS FOR RADIATION CONTROL AND SAFETY GUARANTEES IN OCCUPATIONAL AND PUBLIC IRRADIATION

Article 3. Principles for controlling occupational and public radiation exposure

1. Organizations and individuals conducting radiation work must ensure that individual radiation doses for radiation workers and the public do not exceed the dose limits specified in Appendix I attached to this Circular.

2. Organizations and individuals conducting radiation work must implement technical and administrative measures prescribed in this Circular to reduce individual radiation doses for radiation workers and the public to the lowest reasonably achievable level.

Article 4. Employment of Workers in Radiation Work

1. Individuals under 18 years old shall not be employed in radiation work. In cases where apprentices, students aged 16 to 18 years old related to radiation work use radiation sources during their studies, they may only work in controlled areas or supervised areas with the condition of having specialized staff guidance.

2. Individuals suffering from diseases contraindicated for radiation according to the regulations of the Ministry of Health shall not be employed.

3. Radiation workers certified by healthcare facilities as not being fit to continue radiation work must have their working conditions changed.

4. Female radiation workers who are pregnant must inform the safety supervisor about their pregnancy, and if they wish to temporarily change their working conditions, the head of the organization or individual conducting radiation work must arrange suitable alternative work.

Article 5. Radiation Safety Training for Radiation Workers

1. Organizations and individuals conducting radiation work must organize training when hiring new employees and periodically retrain radiation workers on radiation safety.

2. Radiation workers must undergo radiation safety training courses as required by the radiation safety supervisor.

Article 6. Control of Radiation Sources

Organizations and individuals conducting radiation work must comply with the following requirements to control radiation sources:

1. Ensure the quantity of radiation sources and the activity of radioactive sources is minimized to perform radiation work.

2. Store radioactive sources in safe locations with good shielding and apply radiation protection and radioactive contamination control measures.

3. Regularly inventory radiation sources.

4. Continuously check for leaks of radioactive sources.

5. Apply safety measures when transporting radioactive sources within and outside the facility.

6. Implement the collection, treatment, storage, disposal of radioactive waste, used radioactive sources, and control the discharge levels of radioactive waste into the environment in accordance with the law.

Article 7. Radiation Shielding Design

1. When calculating radiation shielding design for controlled areas and supervised areas, organizations and individuals conducting radiation work must apply an occupational radiation dose constraint less than or equal to 3/10 of the dose limit for radiation workers.

2. When calculating radiation shielding design for public areas, organizations and individuals conducting radiation work must apply a public radiation dose constraint less than or equal to 3/10 of the dose limit for the public based on consideration of the following factors:

a) Contributions to dose from other radiation sources and radiation work, including sources and radiation work that may arise in the future;

b) Potential changes that could affect public radiation exposure such as changes in source characteristics and operation;

c) Good operating experience with similar radiation sources or radiation work.

3. Nuclear facilities handling or storing radioactive waste in their design documentation must have data on foundation construction, groundwater, surface water, potable water; assess permeability and transport of radionuclides in soil and water; demonstrate that the design can prevent leakage of radioactive material into soil, water, and air.

Article 8. Controlled Area and Supervisory Area

1. Organizations and individuals conducting radiation work must establish a controlled area at locations satisfying one of the following conditions:

a) The potential radiation dose exceeds or equals 6 mSv/year;

b) There is a risk of radioactive contamination;

c) Nuclear reactor control room, radiotherapy machine, accelerator, industrial irradiation equipment.

2. Organizations and individuals conducting radiation work must establish a supervisory area at locations meeting the condition that the potential radiation dose exceeds 1 mSv/year and is less than 6 mSv/year.

Article 9. Control of Access to Radiation Sources and Entry and Exit from Controlled and Supervisory Areas

1. Organizations and individuals conducting radiation work using radiation sources must apply administrative or technical measures appropriate for controlling access to radioactive sources as follows:

a) Equip联动翻译第二部分的内容：安装联锁系统或使用钥匙的锁具，用于存放和使用第一类和第二类放射源的地点；使用加速器的地点；处理和加工放射性物质、放射性药物的地点以及存放放射性废物的区域，依据《辐射安全—放射源分类与分级技术规范》QCVN 6:2010-BKHCN；

b) Post warning signs and use barriers to prevent access to the source;

c) Require the use of entry permits for these areas; wear identification cards or assign supervisors to monitor entry and exit from the controlled area;

d) Establish internal regulations controlling persons authorized to approach radioactive sources.

2. Organizations and individuals conducting radiation work must apply appropriate administrative and technical measures to control entry and exit from supervisory areas as follows:

a) Establish internal regulations for entering these areas;

b) Post warning signs and use barriers to prevent entry and exit from this area.

Article 10. Control of Surface Radioactive Contamination and Airborne Radioactive Contamination

Organizations and individuals conducting radiation work using open radioactive sources must control surface radioactive contamination and airborne radioactive contamination through the following measures:

1. Use closed systems such as fume hoods, glove boxes.

2. Use decontaminable materials for walls, floors, and other surfaces prone to radioactive contamination.

3. Implement measures to prevent the spread of radioactive contamination.

4. Use ventilation systems with filters for radioactive substances.

5. Use dosimeters, radiological contamination detectors, and other tests to monitor and assess levels of contamination.

Article 11. Personal Protective Equipment and Radiation Measurement Devices

1. Organizations and individuals conducting radiation work must equip radiation workers with personal protective equipment as follows:

a) Workers performing radiation work with a risk of radioactive contamination must be provided with protective clothing, gloves, shoes, boot covers or leg covers, head coverings, and masks to protect against radioactive contamination;

b) Workers using X-ray equipment for diagnostic imaging must be provided with lead aprons, thyroid shields, and lead glasses;

c) Workers operating interventional X-ray equipment, doctors, and technicians participating in interventional procedures must be provided with lead aprons, thyroid shields, lead gloves, and appropriate lead glasses;

d) Workers using radioactive sources in well logging exploration must be provided with source tongs and gloves.

2. At the entrance to a controlled area with a risk of radioactive contamination, organizations and individuals conducting radiation work must provide radiation workers with suitable dosimetry devices; at the exit from the area, shower facilities, hand washing stations, storage areas for contaminated items, and equipment for body contamination checks, clothing, and items taken out of the area must be arranged.

3. Personal protective equipment, dosimetry devices, and body contamination checking equipment must meet national technical standards or internationally recognized standards; they must be properly stored and regularly inspected and maintained.

4. Radiation workers must be fully instructed on the use and inspection of personal protective equipment, dosimetry devices, and body contamination checking equipment.

5. Radiation workers must use personal protective equipment, dosimetry devices, and body contamination checking equipment strictly according to instructions.

Article 12. Radiation safety rules and work procedures

1. Organizations and individuals conducting radiation work must establish radiation safety rules and work procedures that are appropriate; radiation safety rules must include requirements for compliance with work procedures and safety instructions, requirements for personal dose monitoring, requirements for the use of personal protective equipment, radiation measuring devices, and personal dosimeters, responsibilities to report unusual events that may cause radiation safety incidents, and other specific requirements suitable for radiation work.

2. Radiation workers must comply with radiation safety rules and work procedures.

Article 13. Radiation control for visitors, caregivers, and patients leaving the facility

Organizations and individuals conducting radiation work using radiation sources for diagnosis and treatment must control radiation exposure for visitors, caregivers, and patients leaving the facility through the following measures:

1. Assign personnel knowledgeable about safety and protection against radiation to accompany visitors, caregivers, and patients into the controlled area.

2. Provide comprehensive information and radiation safety instructions to visitors before they enter the controlled area.

3. Ensure that the radiation dose received by caregivers, supporters, and visitors during diagnosis, testing, or radiation therapy does not exceed the dose limit specified in Appendix I attached to this Circular.

4. Only allow patients who have received radioactive drugs for diagnosis and treatment to be discharged when the radioactivity level in their bodies does not exceed the limits set forth in the legal guidelines for ensuring radiation safety in healthcare.

Article 14. Radiation monitoring of work areas

1. Organizations and individuals conducting radiation work must carry out radiation monitoring of work areas.

2. Radiation monitoring of work areas must be conducted regularly, systematically, commensurate with the level and potential for radiation exposure of the radiation work, and ensure the following requirements:

a) Must follow predetermined measurement quantities, methods, procedures, positions, times, and frequencies of radiation monitoring;

b) The investigation levels for measurement positions specified in point a of this clause must be established based on actual evaluation data from the facility or good practices from similar facilities;

c) The frequency of radiation monitoring of work areas must be consistent with the level of risk of radiation work performed in those areas and must not be less than once a year;

d) Radiation monitoring equipment must meet technical standards, national technical standards, or international standards and must be maintained, tested, and calibrated periodically. The radiation monitoring requirements stipulated in Clause 2 of this Article must be compiled into a monitoring program and submitted with the application for a permit and retained in the work area radiation monitoring file.

3. The radiation monitoring requirements stipulated in Clause 2 of this Article must be compiled into a monitoring program and submitted with the application for a permit and retained in the work area radiation monitoring file.

4. Results of radiation monitoring of work areas must be reported to radiation workers and their direct supervisors.

Article 15. Monitoring and Evaluation of Occupational Radiation Exposure

1. Organizations and individuals conducting radiation work must equip personal dosimeters for all employees working in controlled areas and supervised areas.

2. Organizations and individuals conducting radiation work must use personal dose measurement services from facilities registered to operate support services for nuclear energy applications.

3. Organizations and individuals conducting radiation work must establish and ensure compliance with procedures for using personal dosimeters and handling abnormal situations involving personal dosimeters, including the following contents:

a) Radiation workers must use radiation monitoring devices and personal dosimeters correctly and reasonably, and immediately report to the safety supervisor if the personal dosimeter falls into a radiation field, becomes contaminated with radioactive material, or is damaged or lost.

b) In cases where the personal dosimeter falls into a radiation field, becomes contaminated with radioactive material, or is damaged, the personal dosimeter must be immediately transferred to the unit providing personal dose measurement services. During the waiting period for the dose reading results, the facility owner must provide new personal dosimeters for employees or implement all necessary safety measures to ensure that the dose does not exceed the average dose received by the employee; the entire incident and related documents must be recorded in a file and retained.

c) The nature, frequency, and accuracy of occupational radiation exposure monitoring must be determined, taking into account the magnitude and potential changes in exposure levels, the capability and magnitude of potential exposure. The measurement frequency shall not exceed once every three months.

4. Organizations and individuals conducting radiation work must ensure that when there is radiation exposure, in addition to being equipped with personal dosimeters, radiation workers must apply direct or indirect dose assessment methods based on background radiation monitoring results, workplace radioactive substance concentrations, protective equipment used, and information about the location and duration of radiation exposure.

Article 16. Health Examination for Radiation Workers

1. Organizations and individuals conducting radiation work must organize health examinations for radiation workers at recruitment, annually during employment, and upon termination of radiation-related work.

2. Radiation workers must undergo health examinations as required by the safety supervisor.

Article 17. Radiation Safety Records

1. Organizations and individuals conducting radiation work must establish, regularly update, and retain records specified in Clause 1 of Article 29 of the Atomic Energy Law, including the following contents:

a) Records on radioactive sources, nuclear materials, radiation equipment, nuclear equipment; changes, repairs, and upgrades to radiation equipment and nuclear equipment;

b) Radiation monitoring area records, measurements, and maintenance, inspection, calibration records, including: radiation monitoring plans, radiation monitoring activities, periodic radiation monitoring results, maintenance, inspection, calibration documentation for radiation monitoring equipment, and other related documents;

c) Logs and records of radiation and nuclear incidents occurring during the conduct of radiation work;

d) Training records of radiation workers;

đ) Health records of radiation workers, recording annual and emergency health examination results for each worker;

e) Radiation dose records of radiation workers according to the model prescribed in Appendix III of this Circular. Radiation dose records of radiation workers must be updated at least once a year and immediately after exceeding investigation, limit dose levels, and upon request;

g) Inspection conclusions, and documents regarding the implementation of requirements by competent authorities;

h) Public radiation monitoring records including: environmental radiation monitoring programs and results, calibration results of monitoring equipment.

2. Organizations and individuals conducting radiation work have the responsibility to provide radiation workers and other relevant parties with occupational radiation exposure records; implement retention and transfer of occupational radiation exposure control records in accordance with Article 29 of the Atomic Energy Law. Health records and radiation dose records of radiation workers must be retained for thirty years from the date they no longer perform radiation work.

3. Radiation workers must preserve and retain personal radiation dose tracking logs. Provide organizations and individuals conducting radiation work with previous information related to their occupational radiation exposure.

Article 18. Internal supervision of the implementation of occupational radiation control requirements

Organizations and individuals conducting radiation work must periodically review the following contents:

1. Radiation safety regulations, working procedures.

2. The monitoring of the workplace area and the environmental surveillance program.

3. The monitoring and evaluation of individual radiation dose.

4. Record keeping.

5. The scope of controlled and monitored areas.

Article 19. Public radiation control

Organizations and individuals conducting radiation work must establish and implement a monitoring program to ensure that public exposure from radiation sources of their organizations and individuals is properly assessed, fully documented, and approved by the competent state management agency.

Article 20. Reporting on the results of occupational and public radiation control assessment

1. Annually in November or upon request, organizations and individuals conducting radiation work must submit a current safety status report as prescribed in Article 20 of the Atomic Energy Law and a report on the results of radiation control and ensuring radiation safety in occupational and public exposures to the Radiation and Nuclear Safety Administration. Medical diagnostic X-ray equipment operating facilities must send this report to the Department of Science and Technology where the permit for conducting radiation work was issued.

2. The report on the results of radiation control and ensuring radiation safety in occupational and public exposures includes the following contents:

a) Results of individual occupational radiation dose;

b) Results of workplace and public area monitoring;

c) Evaluation of deviations from the safety assessment that has been licensed;

d) Evaluation of cases of overexposure (if any);

đ) Report on incidents of radiation and nuclear accidents as well as cases of collective doses exceeding the investigation level.

Section 3

RADIATION CONTROL IN CASES OF RADIATION AND NUCLEAR INCIDENTS AND OTHER SPECIAL CASES

Article 21. Radiation control in cases of radiation and nuclear incidents

Organizations and individuals conducting radiation work causing radiation levels, radioactive contamination levels, and radioactive discharge levels exceeding permissible limits due to radiation work at the facility must take the following measures:

1. Establish and maintain the capability to conduct emergency radiation monitoring.

2. Apply all measures to bring these levels below the permissible limits.

3. Implement provisions in the radiation and nuclear incident response plans at various levels.

Article 22. Radiation control for radiation and nuclear incident responders

Organizations and individuals conducting radiation work, employers, and organizations responsible for responding to radiation and nuclear incidents at various levels have the responsibility to:

1. Manage, control, and retain the radiation dose of personnel participating in radiation and nuclear incident responses.

2. Ensure that the radiation dose for personnel participating in radiation and nuclear incident responses does not exceed 50 mSv except in the following cases:

a) For the purpose of saving lives;

b) When performing actions to prevent serious injuries or death or to prevent conditions that could lead to significant impacts on people and the environment;

c) When performing actions to avoid large collective doses.

3. Ensure that personnel participating in radiation and nuclear incident responses are informed of health risks to them and protective measures before undertaking intervention actions with received radiation doses exceeding 50 mSv.

4. Ensure that under no circumstances will personnel participating in radiation and nuclear incident responses receive effective doses exceeding 500 mSv.

The radiation dose of radiation workers when participating in radiation and nuclear incident responses shall not be counted towards occupational dose for control within dose limits. In cases where personnel participating in radiation and nuclear incident responses have received effective doses greater than 200 mSv, they must undergo a health examination and medical consultation before continuing their radiation work.

Article 23. Public radiation exposure control in nuclear and radiological emergency situations

Organizations and individuals conducting radiation work, organizations at all levels responsible for responding to nuclear and radiological emergencies must ensure:

1. Implement protective actions and emergency responses immediately before radiation exposure occurs. The dose levels determining protective and emergency response actions in case of nuclear and radiological incidents are specified in Appendix II attached hereto.

2. Evaluate the effectiveness of implemented actions and adjust them accordingly.

3. Compare residual radiation doses with reference levels (from 20 to 100 mSv) to determine the priority level of protection for groups with residual radiation doses exceeding the reference level.

4. For nuclear facilities, there must be plans for emergency protection zones (EPZs) and planning zones for emergency protection (UPZs) based on the dose levels specified in Appendix II attached hereto.

Article 24. Radiation control for radioactive contaminated metal waste

Organizations and individuals engaged in exporting, importing, producing, consuming, and recycling metal waste and steel billets have the responsibility to:

1. Monitor and detect radioactive substances, contaminated objects, and radioactive sources mixed in metal waste and semi-finished steel billets.

2. Report in writing to the State Management Agency for Radiation and Nuclear Safety if radioactive substances, contaminated objects, and radioactive sources are found mixed in metal waste and semi-finished steel billets.

3. Immediately implement the following measures:

a) Return the shipment containing radioactive contamination or radioactive sources outside of control to the exporting country;

b) Collect, store, and manage radioactive-contaminated goods according to regulations on radioactive waste management;

c) Use technical and administrative measures to restrict access to areas with radioactive-contaminated goods.

Article 25. Control and assurance of radiation safety for employees working in environments with high concentrations of Radon-222 gas

1. Employers must apply radiation control and safety measures for employees working in conditions where the concentration of Radon-222 gas at the workplace exceeds 1000 Becquerels (Bq) per cubic meter of air, as stipulated for organizations and individuals conducting radiation work.

2. Employers in places where the concentration of Radon-222 gas exceeds the level specified in Clause 1 of this Article, depending on specific conditions, must apply measures to control and reduce the concentration of radon in the workplace environment such as increasing ventilation, diluting the air in the work area with outdoor air, cleaning the air using activated carbon or other appropriate methods.

Article 26. Radiation control for personnel involved in radiation safety inspection and audit work

State agencies performing functions of inspection and audit of radiation safety must provide personal dosimeters and evaluate individual radiation doses for staff directly involved in radiation safety inspections and audits.

Section 4

REQUIREMENTS FOR ORGANIZATIONS AND INDIVIDUALS PROVIDING PERSONAL DOSIMETRY SERVICES

Article 27. Personal dosimeters used in personal dosimetry services

1. Personal dosimeters must be suitable for the type of radiation work and ensure that the measurement index on the dosimeter cannot be arbitrarily changed.

2. The measurements and calibrations of personal dosimeters must be carried out according to the following practical quantities:

a) Hp (10) for effective whole-body dose;

b) Hp (3) for equivalent eye dose;

c) Hs (0,07) for equivalent skin dose.

Article 28. Responsibilities of organizations and individuals providing personal dosimetry services

Organizations and individuals providing personal dosimetry services shall have the responsibility to:

1. Have sufficient equipment and personnel to provide personal dosimetry services in accordance with the law.

2. Develop and implement a quality assurance program.

3. Guide organizations and individuals on how to use personal dosimeters in accordance with the prescribed procedures.

4. The personal dosimetry result report must include the following key information: name of the organization or individual conducting the radiation work, address of the agency, measurement period, list of radiation workers along with dose values, measured quantity, and confirmation from the service provider.

5. Immediately report to the Radiation and Nuclear Safety Agency and the local Science and Technology Department cases where radiation workers exceed their dose limits.

6. Update occupational radiation dose data of individuals into the national occupational exposure database in accordance with the guidelines of the Radiation and Nuclear Safety Agency.

Section 5

IMPLEMENTATION

Article 29. Responsibility for Implementation

The Radiation and Nuclear Safety Agency, provincial Science and Technology Departments under the central government, and related organizations and individuals are responsible for implementing this Circular.

Article 30. Effective Date

1. This Circular shall take effect 45 days from the date of signature.

2. During implementation, if there are any difficulties or new issues arise, they should be promptly reported to the Ministry of Science and Technology for review and amendment./.