1. Occupational Radiation Protection during High Exposure Operations
IAEA Training Material on Occupational Radiation Protection
Occupational Radiation Protection during 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.
03 April 2014

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
EP category
Description
Criteria I
Facilities, such as nuclear power plants, for which on-site events (including very low probability events) are postulated that could give rise to severe deterministic health effects off the site, or for which such events have occurred in similar facilities.
- Reactors with power levels greater than 100 MW(th) (power, nuclear ship and research reactors) - Facilities and/or locations containing recently discharged irradiated reactor fuel with a total of more than about 0.1EBq of 137Cs (equivalent to the inventory in a 3000 MW(th) reactor core) - Facilities with inventories of dispersible radioactive material sufficient to result in severe deterministic effects off the site. II
Facilities, such as some types of research reactors, for which on-site events are postulated that could give rise to doses to people off the site that warrant urgent protective action in accordance with international standards, or for which such events have occurred in similar facilities. Threat category II (as opposed to threat category I) does not include facilities for which on-site events (including very low probability events) are postulated that could give rise to severe deterministic health effects off the site, or for which such events have occurred in similar facilities.
- Reactors with power levels greater than 2 MW(th) and less than or equal to 100 MW(th) (power reactors, nuclear ship and research reactors). - Facilities and/or locations containing recently discharged irradiated reactor fuel requiring active cooling
- Facilities with potential for an uncontrolled criticality within 0.5 km of the off-site boundary. - Facilities with inventories of dispersible radioactive material sufficient to result in doses warranting urgent protective action being taken off the site.
III
Facilities, such as industrial irradiation facilities, for which on-site events are postulated that could give rise to doses that warrant or contamination that warrants urgent protective action on the site, or for which such events have occurred in similar facilities. Threat category III (as opposed to threat category II) does not include facilities for which events are postulated that could warrant urgent protective action off the site, or for which such events have occurred in similar facilities.
- Facilities with the potential, if shielding is lost, for causing direct external dose rates of more than 100 mGy/h at 1 m Facilities with potential for an uncontrolled criticality more than 0.5 km from the off-site boundary
- Reactors with power levels of less than or equal to 2 MW(th) Facilities with inventories of radioactive material sufficient to result in doses warranting urgent protective action being taken on the site. 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
EP category
Emergency preparedness arrangements to promptly
I & II
Classify an emergency
Protect those on the site and on-site emergency workers
Mitigate the consequences of the emergency
Notify and recommend protective actions for the public to off-site officials
Obtain off-site assistance
Conduct environmental monitoring near the facility
Assist off-site officials in keeping the public informed
III
Inform off-site officials
Obtain offsite assistance
Ensure that there are no off-site risks 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)
Classification
Description
General Emergency
Actions shall be promptly taken to mitigate the consequences and to protect people on the site and within the precautionary action zone (PAZ) and urgent protective action planning zone (UPZ).
Site Area Emergency
Actions shall be promptly taken to mitigate the consequence, to protect people on the site and to make preparations to take protective actions off the site if this becomes necessary.
Facility Emergency
Actions shall be promptly taken to mitigate the consequences and to protect people on the site. Emergencies in this class can never give rise to an off-site threat.
Alerts
Actions shall be promptly taken to assess and mitigate the consequence and to increase the readiness of the on-site and off-site response organizations. 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
The Regulatory 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