Reflecting local economic parameters in ALARA evaluations for the reuse of decommissioning remaining building.

Abstract

After nuclear power plant decommissioning, remediation is required to ensure that radiation doses from residual radioactivity in remaining buildings do not exceed 0.1 mSv yr^-1, and decontamination below this legal criterion may be considered from the as low as reasonably achievable (ALARA) perspective. Accordingly, this study conducted an ALARA evaluation of remedial actions for the reuse of remaining buildings at Kori Unit 1 to determine the need for additional remediation and to identify the optimal remedial action. Evaluation factors were identified based on the ALARA Action Level methodology of NUREG-1757 and analyses of U.S. license termination plans and were redefined to reflect site-specific characteristics. Cost factors were derived for selected remedial actions, ALARA Action Levels were calculated, and the impact of the level of decontamination was analysed. The results showed that all remedial actions yielded ALARA Action Levels greater than unity, indicating that decontamination below the derived concentration guideline level is unnecessary. Shaving exhibited the lowest ALARA Action Level and was identified as the remedial action closest to satisfying the ALARA principle. These results are expected to support ALARA-based planning of remediation activities following nuclear power plant decommissioning.