Accidental Dose Control

DOE-STD-1121-98

8.2.4 Uncertainties

It is current practice in the DOE to use point estimates of dose and to ignore ranges of uncertainties

when comparing doses to limits and administrative control levels. However, sites may consider

uncertainties when invoking work restrictions based on professional judgment. For example, an HE,50

value with a multiplicative (lognormal) uncertainty characterized as 1.5 rems ( or by 2) has a roughly

5% chance of actually exceeding 6 rems. This may exceed the "comfort level" of those responsible for

dose management. While comparing point estimates of doses with limits and administrative control

levels, sites may still consider using an upper confidence limit (such as the 95% upper confidence limit on

a dose) for invoking work restrictions or other dose control practices.

8.3 ACCIDENTAL DOSE CONTROL

Unlike external irradiation, whose course cannot be altered after exposure, doses from retained

quantities of radioactive materials can be influenced after intake occurs in some cases. While intervention

following intake is usually a medical matter, it is necessary to involve the internal dosimetry program.

Methods of reducing dose following an intake include enhanced decorporation ranging from washing to

debridement, excision, blocking, chelation, and forcing fluids.

8.3.1 Incident Dose Management

Significant intakes of radionuclides usually occur as the result of accidents, not from routine,

planned operations. A prompt response is needed following indication that an unexpected intake has

occurred. The time interval and degree of urgency associated with the follow-up actions depend on

several factors, including the possible significance of the exposure and the elapsed time from its

occurrence to its detection.

8.3.2 Preparation for Incidents Involving Intake

Management at a facility should be prepared for an incident involving a worker receiving an intake

of radioactive material even though the probability of an incident may be very small. Management

should have an emergency action plan for response to a potential or unplanned intake of radioactive

material and be prepared to follow it. The amount of detail in the plan should be commensurate with the

possible severity of an accidental intake.

An emergency action plan to deal with accidental internal intakes should include: (1) plans for

activating key response functions, such as internal dosimetry, analytical laboratory, and medical support,

(2) the readiness of facilities, (3) the training of personnel, and 4) predetermined specifications for

bioassay and other measurements.

The elements of this plan should include the following:

decision levels for determining when monitoring data or accident events necessitate emergency

medical response

responsibilities of the affected worker, the health physicist, medical staff, and management or

supervisory personnel