Occupational Radiation Protection during High Exposure Operations

1. IAEA Training Material on Occupational Radiation Protection Occupational Radiation Protectionduring High Exposure Operations Lecture 1 Introduction

2. Contents • Background • Objective • Scope • Structure • Basis of radiation protection during nuclear and radiological emergency operations • Radiation protection principles • Summary

3. 1. Background At 15:37 on11th March 2011, a Tsunami struck the Fukushima Dai-ichi Nuclear Power Station (FDNPS), 50 minutes after the Great East Japan Earthquake, which initiated a nuclear accident unprecedented in both scale and timeframe. It turned out that an appropriate radiation protection procedures and instructions that gave the method and the attitude of operational radiation protection to workers in the installation during the emergency was not available. The basis for the radiation protection procedures and instructions (called here the manual) is presented during these lectures. The manual plans to enable the planning, preparedness and training of emergency workers so as to mitigate the exposure in facilities during future accidents and emergencies. 3

4. 1. Background • The response to a nuclear or radiological emergency must be well coordinated and arrangements must be appropriately integrated with those for a conventional emergency. • Many misconceptions prevail concerning nuclear and radiological emergencies and the possible health effects of radiation exposure which could lead to inappropriate actions being taken.

5. 2. Objective The aim of this manual is to provide practical guidance for emergency workers and other employees involved in operation and radiation control of a plant during operations with high occupational exposure. 5

6. 3. Scope • The presentations: • Include emergency response procedures to protect the workers in nuclear installation or radiation facility for different types of radiological emergencies or accidents at a reactor, reprocessing plant or other large nuclear facility. • Are directed to the radiation protection officers who will take responsibility for radiation protection during the emergency • Do not apply to the first responders for a radiation emergency • Apply to the training of trainers of radiation workers in facilities. 6

7. 4. Structure • Introduction • Lessons learnt from occupational radiation protection in past accidents • Health effect caused by radiation and basis for radiological protection • Medical management of radiological casualties • Roles and responsibilities on occupational radiation protection with high exposure • IAEA documents on occupational radiation protection with high exposure • Basic concepts of occupational radiation protection with high exposure • Preparedness and action in emergency • Radioactive sources to be considered • Practical radiation monitoring and dose evaluation • Personal protection and dose reduction measures • Communication 7

8. 5. Basis of radiation protection on nuclear and radiological emergency • Types of radiation emergencies and threat categories • Establishing emergency management and operations • Identifying, notifying and activating • Taking mitigating action • Taking urgent protective action • Protecting emergency workers • Managing the medical response 8

9. 5.1. Types of radiation emergencies and threat categories 1) Nuclear emergencies may occur at: • Nuclear reactors (research, ship, power reactors) • Fuel cycle facilities (e.g. fuel processing plants) • Storage facilities for large quantities of spent fuel or liquid or gaseous radioactive material 9

10. Emergency planning category for nuclear and radiation related hazards 10

11. 5.1. Types of radiation emergencies and threat categories 2) Radiological emergencies include: • Uncontrolled (abandoned, lost, stolen or found) dangerous sources • Misuse of industrial and medical dangerous sources (e.g. of those used in radiography) • Public exposures and contamination from unknown origins • Re-entry of a satellite containing radioactive material • Serious overexposures • Malicious threats and/or acts • Transport emergencies 11

12. 5.2. Establishing emergency management and operations The on-site emergency response shall be promptly executed and managed without impairing the performance of the continuing operational safety functions. For facilities in threat categories I, II and III • The transition from normal to emergency operations shall be clearly defined and shall be effectively made without jeopardizing safety. • The responsibilities of everyone who would be on the site in an emergency shall be designated as part of the arrangements for transition. • It shall be ensured the ability of the operating personnel to ensure safe and secure operation while taking mitigatory actions. 12

13. Responsibilities for emergency preparedness and response 13

14. 5.2. Establishing emergency management and operations The operator should be responsible, as appropriate, for: • Identifying and/or detecting an emergency or hazard • Taking immediate action to mitigate the consequences of the emergency • Protecting individuals on the site and within the area controlled by the operator • Declaring the class of the emergency • Notifying off-site officials and possibly providing them with recommendations on protective actions and technical assistance • Establishing ongoing communication with off-site officials • Assisting the off-site officials in keeping the public informed and countering incorrect information and inappropriate public reactions • Providing initial radiological monitoring and technical advice 14

15. 5.3. Identifying, notifying and activating The operating organization of a facility or activity in category I, II, III or IV shall make arrangements for promptly classifying, on the basis of the hazard assessment, a nuclear or radiological emergency warranting protective actions and other response actions to protect workers, emergency workers, members of the public and, as relevant, patients and helpers in an emergency in accordance with the protection strategy. 15

16. 5.3. Identifying, notifying and activating This shall include a system for classifying all types of nuclear or radiological emergency as follows: (a) General emergency (b) Site area emergency (c) Facility emergency 16

17. 5.3. Identifying, notifying and activating For facilities and activities in categories I, II and III, and for category IV, arrangements shall be made: • to promptly recognize and classify a nuclear or radiological emergency; • upon classification, to promptly declare the emergency class and to initiate a coordinated and pre-planned on-site response; • to notify the appropriate contact points and to provide sufficient information for an effective off-site response; and • upon notification, to initiate a coordinated and pre-planned off-site response, as appropriate, in accordance with the protection strategy. 17

18. Emergency Action Levels (EALs) 18

19. 5.4. Taking mitigating action The operating organization of a facility in category I, II or III shall make arrangements to promptly assess and anticipate: • abnormal conditions at the facility; • exposures and radioactive releases and releases of other hazardous material; • radiological conditions on the site and, as appropriate, off the site; and • any exposures or potential exposures of workers and emergency workers, the public and, as relevant, patients and helpers in an emergency. 19

20. 5.4. Taking mitigating action These assessments shall be used: • for deciding on mitigatory actions to be taken by the operating personnel; • as a basis for emergency classification; • for deciding on protective actions and other response actions to be taken on the site, including those for the protection of workers; • for deciding on protective actions and other response actions to be taken off the site; • where appropriate, to identify those who could potentially have been exposed on the site at levels requiring appropriate medical attention. 20

21. 5.5. Taking urgent protection action In a nuclear or radiological emergency, the goals of emergency response are: • To regain control of the situation and to mitigate consequences; • To save lives; • To avoid or to minimize severe deterministic effects; • To render first aid, to provide critical medical treatment and to manage the treatment of radiation injuries; • To reduce the risk of stochastic effects; • To keep the public informed and to maintain public trust; • To mitigate, to the extent practicable, non-radiological consequences; • To protect, to the extent practicable, property and the environment; • To prepare, to the extent practicable, for the resumption of normal social and economic activity 21

22. 5.5. Taking urgent protection action The government through the Regulatory Authority shall ensure that arrangements are in place to assess emergency conditions and to take urgent protective actions and other response actions effectively in a nuclear or radiological emergency. 22

23. 5.6. Protecting emergency workers TheRegulatory Authority shall ensure that arrangements are in place to protect emergency workers and to protect helpers in an emergency. This shall include: • Arrangements to assess continually and to record the doses received by emergency workers • Procedures to ensure that doses received and contamination are controlled in accordance with established procedures and international standard • Arrangements for the provision of appropriate specialized protective equipment, procedures and training for emergency response in the anticipated hazardous conditions 23

24. 5.7. Managing the medical response The Regulatory Authority shall ensure that arrangements are in place for the provision of appropriate medical screening and triage, medical treatment and longer term medical actions for those people who could be affected in a nuclear or radiological emergency 24

25. 6. Radiation protection principles The main object of radiation protection (RP) is to avoid deterministic effects by keeping doses below the relevant thresholds and to reduce the probability of stochastic effects as far as is reasonably achievable. This shall be achieved by the following requirements: • Justification of practices • Optimization of protection and safety • Dose limitation 25

26. a) Justification of practices No practice or source within a practice should be authorized unless the practice produces sufficient benefit to the exposed individuals or to society to offset the radiation harm that it might cause; That is: unless the practice is justified, taking into account social, economic and other relevant factors. In the case of emergencies, include a part on justification of mitigating actions 26

27. b) Optimization of protection and safety In relation to exposures from any particular source within a practice, expect for therapeutic medical exposures, protection and safety shall be optimized in order that the magnitude of individual doses, the number of people exposed and the likelihood of incurring exposures all be kept as low as reasonably achievable, economic and social factors being taken into account, within the restriction that the doses to individuals delivered by the source be subject to dose constraints. 27

28. b) Optimization of protection and safety From the view point of control of accidental and emergency occupational exposures, ICRP shows in Publication 63 and reiterated in Publication 109 three categories of working conditions are defined in relation to the actions that may be required following an accident affecting the public. • Category I: Urgent action at the site of the accident • Category II: Implementing early protective actions and taking action to protect public • Category III: Recovery operations 28

29. b) Optimization of protection and safety Category I: ・Workers involved in Category 1 operations are most likely to be plant personnel who should be provided with appropriate means to control and quantify their exposures using means appropriate to the situation, such as direct reading or alarming dosimeters. ・For this category, it is not appropriate to recommend rigid dose limits. ・This type of emergency intervention usually has a high degree of justification and is often aimed at saving human lives or preventing individuals from incurring high doses beyond the thresholds for deterministic effects or prevention the development of catastrophic conditions, which might result in significant exposure of members of the public. 29

30. b) Optimization of protection and safety Category I: ・For the individuals undertaking such emergency actions every effort should be made to keep doses below those at which serious deterministic effects may occur. 30

31. b) Optimization of protection and safety Category III: • Category 3 operations involve workers undertaking recovery operations, such as repairs to the plant and site, waste disposal, decontamination of the site and the environment. • This work can be carefully planned. It should be treated as a practice and doses should be maintained below the dose limits. • The training required for workers involved in Category 3 operations will depend on the actual situation and cannot be identified in advance. • The assessment of doses to workers in Category 3 operations will be the same as for any occupationally exposed workers, who are subject to the system of radiological protection for practices. 31

32. b) Optimization of protection and safety The workers involved in all categories should be informed on request of the doses received and the possible health consequences. The doses received in emergency situations should not compromise the further employment of the worker in work with ionizing radiation. However, where a worker has received an emergency exposure around or above the threshold for deterministic effects, the worker should be referred to a physician 32

33. c) Dose limitation The normal exposure of individuals shall be restricted so that neither the total effective dose nor the total equivalent dose to relevant organs or tissues, caused by the possible combination of exposures from authorized practices, exceeds any relevant dose limit specified, expect in special circumstances provided for in the Standards. Dose limits shall not apply to medical exposures from authorized practices. 33

34. 7. Summary • In order to be effective, the response to a nuclear or radiological emergency must be well coordinated and arrangements must be appropriately integrated with those for a conventional emergency. • In addition, the misconceptions prevailing concerning nuclear and radiological emergencies and the possible health effects of radiation exposure could lead to inappropriate actions being taken. • Consequently, preplanning on the basis of established principles of radiation protection and safety is essential. Such preplanning can be achieved only through a coordinated approach. • The aim of this manual is to provide practical guidance on occupational radiation protection for employee involved in operation and radiation control of a plant during operations with high occupational exposure, particularly those engaged in urgent actions at the site of the accident. 34