Case study of characterization survey for nuclear facility decommissioning: lesson learned for regulatory perspective in Korea

초록

Accurate characterization of residual radioactivity is a critical regulatory requirement and technical challenge in nuclear facility decommissioning. This review analyzes characterization survey strategies and statistical testing methods from a regulatory perspective, focusing on how contamination-level-based classification, the Data Quality Objectives (DQO) process, and statistically robust decision-making interact to support site release determinations. Drawing upon U.S. methodologies (e.g., MARSSIM, NUREG-1505) and six decommissioning case studies-including power reactors, research facilities, and government laboratories-the study identifies practical patterns in survey unit classification, statistical test selection (Sign Test, Wilcoxon Rank-Sum), and Minimum Detectable Concentration (MDC) justification. A comparative matrix highlights how these elements are applied flexibly under varying site constraints while maintaining regulatory defensibility. The analysis confirms that contamination-informed classification and DQO-driven planning are key to achieving technically sound and regulatorily credible license termination. The study further provides recommendations for Korea, emphasizing the need for codified classification criteria, formal DQO integration, and MDC standardization. The findings support the development of harmonized regulatory guidance that ensures transparency, consistency, and public trust in future decommissioning efforts.

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