IAEA International Atomic Energy Agency Emergency Response Protective Actions Day 10 – Lecture 3

IAEA Objective To present background and guidance on major protective actions, which may be needed in the event of an accident to control the radiation exposures to members of the public 2

IAEA Content Exposure pathways Protection strategy Protective actions Evacuation Sheltering Thyroid blocking Relocation and resettlement Agricultural countermeasures Operational Intervention Levels 3

IAEA Three Major Principles The protective actions should Prevent serious deterministic effects wherever possible Be justified – they should do more good than harm Be optimised – they should do the most good 4

IAEA Exposure Pathways and Protective Actions Exposure of individuals may be external or internal and may be incurred by various pathways The various routes by which individuals may be exposed will influence decisions which protective actions should be taken to prevent or reduce the exposure 5

IAEA Plume Shine from ground contamination (ground shine) Cloud shine Fresh produce Fresh milk Skin contamination Immediate ingestion Inhalation Human Exposure Pathways 6

IAEA Preventive vs. Protective Actions Protective actions in the UPZ taken to avoid consequences to health based on measurements or predictions Preventive, or risk reduction actions in the PAZ taken to avoid the risk of exposure based on plant conditions no time for detailed analysis applies where protective actions may not be adequate or fast enough 7

IAEA Preventive Actions Should be initiated before or shortly after a major release from core damage accident You can predict core damage before a release You can not predict the time or size of release once you have core damage Therefore must act on the status of the core Should not wait for a release before taking action 8

IAEA Emergency Assessment Given large uncertainties and need for timely decisions in order for protective actions to be effective As simple as possible, yet effective Based on best understanding of severe accidents and international guidance Focus on data important for decision-making Do not be side-tracked by data that do not influence the decision-making Considerable time is needed to implement decisions Only use data that will be available at the time 9

IAEA Strategy to Reduce Public Risk Before or shortly after release - based on plant conditions Evacuate or substantial shelter within km Take thyroid blocking near the plant After a release Prompt monitoring to locate areas requiring further protective actions. Restrict consumption of locally grown food to 300 km Monitoring to locate where food restrictions and relocation are warranted 10

IAEA Protective Actions Urgent protective actions Sheltering Evacuation Administration of stable iodine Longer term protective actions Temporary relocation Resettlement Agricultural countermeasures 11

IAEA Sheltering Protects against external radiation from cloud and ground; some protection against inhalation Most effective when properly applied Effectiveness depends on type of dwelling Duration limited to about 2 days Must be prompt May lead to spontaneous evacuation 12

IAEA Types of Shelters and Effectiveness 13

IAEA Evacuation Most effective action for areas close to a facility Must be initiated prior to a release to avoid inhalation from the plume Must be timely to avoid external radiation from the ground Difficult to manage Spontaneous evacuation possible 14

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IAEA Thyroid Blocking KI pills Protect against inhalation and ingestion of radioiodine only Very effective if taken early, especially for children Complex distribution strategies Difficult to distribute during emergency Difficult to maintain if pre-distributed Transient populations? Limited shelf life Large stock piles required Must be part of overall strategy 16

IAEA Relocation and Resettlement To keep population out of the affected areas Relocation: more than 7 days but not more than few months Resettlement: permanent Expensive Disruptive 17

IAEA Psychological Effects of Relocation Relocation is especially dubious Has negative impact on mental well being If aimed to reduce risk for stochastic effects: Consider only future avoidable dose Dose already achieved cannot be reduced Involuntarily relocated people suffer most Elderly people are especially likely to suffer 18

IAEA Agricultural Countermeasures Not to be considered urgent, though it should be timely Applied directly to plants or to soil Appropriate processing of food Expensive Great detriment to farmers: compensation costs Alternate food supplies required Loss of confidence in food supplies 19

IAEA Public Monitoring and Decontamination Skin contamination could contribute to deterministic effects Public should be monitored Should not delay evacuation Screening or monitoring a sample is only practical method Instruct people to shower and change clothes as soon as possible 20

IAEA GILs and GALs Not directly readable on instrument Develop operational intervention levels (OIL) as part of planning OIL readable on instruments used OIL used during accident to make decisions IAEA has developed suggested default OILs Revise defaults during accident 21

IAEA Gamma Dose Rate Measurements in Environment Most important environmental monitoring Easy to measure with simple instrument and little training Can use to decide where to: evacuate shelter give thyroid blocking relocate 22

IAEA Default Gamma Dose Rate OILs 1.0 mSv/h ( 100 mR/h) - Evacuate 0.2 mSv/h (20 mR/h) - Relocate 0.1 mSv/h (10 mR/h) - Thyroid blocking 1.0 µSv/h (100µR/h) - Restrict local food 0.1 µSv/h (10µR/h) - Typical Background 23

IAEA Deposition Marker Isotope OILs to Restrict Food Produced in Contaminated Area 10 kBq/m 2 - I-131 food 2 kBq/m 2 - I-131 milk 2 kBq/m 2 - Cs-137 food 10 kBq/m 2 - Cs-137 milk 24

IAEA Food Concentrations OILs 1 Bq/kg - I-131 in food 0.1 kBq/kg - I-131 in milk, water 0.2 kBq/kg - Cs-137 in food 0.3 kBq/kg - Cs-137 in milk, water 25

IAEA Summary Part of conventional emergency management Objectives of response Practical considerations Favour evacuation close in over other actions for severe accidents Combination of sheltering and evacuation can be effective KI pills can enhance effectiveness of sheltering Operational intervention level Establish OILs and methods before the accident, not during ! Use IAEA support material 26

IAEA Where to Get More Information INTERNATIONAL ATOMIC ENERGY AGENCY  Intervention Criteria in a Nuclear or Radiation Emergency Safety Series No. 109, Vienna (1994) and  Generic procedures for monitoring in a nuclear or radiological emergency IAEA-TECDOC-1092 (1999) 27