Evaluation of Worker Accidents in Safety Analysis: A Common Sense Approach
W. Kennedy, Jr., M. Moeller, S. Merwin
The U.S. Department of Energy (DOE) is requiring that radiological exposure standards and accident analysis methods be applied during the design of a new nuclear, non-reactor facility to ensure protection of its facility workers. The results are to be documented in preliminary and final safety analysis reports supporting the conclusion that the facility design can operate safely. In a similar manner, the U.S. Nuclear Regulatory Commission (U.S. NRC) is requiring a licensee to address potential accident doses to workers under 10 CFR Part 70 for non-reactor nuclear facilities. Although the approach is a new extension of accepted safety analysis methods that require accident dose assessments to members of the public, several components of the required evaluation of doses to facility workers from accidents are quite unique and subjective. At the hazard identification phase, estimates of unmitigated worker doses for selected accidents can be on the order of hundreds of Sieverts. These doses result because bounding (highly conservative) calculations are required and because the workers will often have a close proximity to significant radiation sources during accidents. With the application of control technologies for worker protection in the facility design, including confinement of radiation sources, provisions for shielding, and provisions for adequate airflow, conservative dose estimates can mitigate or prevent worker doses from accidents. However, the determination of some parameter values used in these dose estimates is subjective. This can often rely on highly uncertain assumptions about exposure duration, localized air concentrations, and the effectiveness of administrative controls. Nonetheless, safety analysis methods evaluating doses to workers from identified accidents can provide useful information in the design and operation of new nuclear facilities.
This abstract was presented at the 35th Annual Midyear Meeting, "Decommissioning and Environmental Restoration", Late Submissions Session, 2/17/2002 - 2/20/2002, held in Orlando, FL.