Dirty Bomb - Limitation of occupational exposure in emergencies

[Jose Julio Rozental <joseroze@netvision.net.il>]

Nevertheless the  inquire, was made directly to the USA Radsafers community, applying national limit regulation, let me add the following comment to my recent 

commentary on this subject sent to list yesterday:

Accidents - Dose Limits do not apply -Exposures can be limited by design, protective measures and emergencyresponse procedures.

The limitation of occupational exposure in emergencies

Let us consider the ICRP recommendations-GOING TO ICRP 60, 1990

a)  - Dose limits do not apply in case of intervention (see 113);

b) - The limitation of occupational exposure in emergencies (see 6.3.2)

(224) Occupational exposures directly due an accident can be limited only by the design of the plant and its protective features and by the provision of emergency

procedures. Ideally, the aim should be to keep the doses within those permitted in normal conditions, but, while this usually possible, it may not always be 

so in serious accidents.

(225) besides the exposures resulting directly from the accident, there will be exposures of emergency teams during emergency and remedial actions.

Even in serious accidents, these can be limited by operational controls. The doses incurred are likely to be higher than in normal situations and should be 

treated separately from any normal doses. Emergencies involving significantexposures of emergency teams are rare, so some relaxation of controls for normal 

situations can be permitted in serious accidents without lowering the long-term level of protection. This relation should not permit the exposures in the control of the 

accident and in the immediate and urgent remedial work to give effective doses of more than about 0.5 Sv. except for life-saving actions, which can rarely be limited

by dosimetric assessments.

The equivalent dose to skin should not be allowed to exceed about 5 Sv, again except for life saving. Once the emergency is under control, remedial work should 

be treated as part of the occupational exposure incurred in a practice.

This means:

a) Emergency interventions that may cause doses to workers in excess of thresholds for serious deterministic effects have a high degree of

justification when they are aimed at saving human life or preventing very large individual doses to members of the public,  well above the thresholds for serious 

deterministic effects-Life Savings and preventing severe consequences there is no dose limits, dose above thresholds for deterministic effects is allowed;

b) When intervention is aimed at preventing an escalation of an accident that might entail substantial individual or collective dose to the public, it will probably still be 

justified by the expected benefit from the mitigation of the consequences, however, in these circumstances workers should not be exposed to doses in excess 

of the threshold for serious deterministic effects.

c) Urgent countermeasures and short term recovery operations: -- No dose limits, all reasonable efforts should be made to keep individual doses below 100 mSv in a year;

d) Longer term recovery operations: -- Dose limits for occupational exposures apply;

e) Dose not directly connected with the accident: -- Dose limits for occupational exposures apply.

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