[1D05-08] Measurement technologies

11:40 AM - 11:55 AM JST(2:40 AM - 2:55 AM UTC)

[1D08] Development of Clearance Measurement and Evaluation Method for Concrete in BWR Buildings(2) Study on Measurement and Evaluation Methods

*Masato WATANABE¹, Takehisa Ookura¹, Ryosuke Tanaka², Naoya Matsushita², Takahiro Fukuhara³, Kazuhiko Takaji⁴ (1. Chubu Electric Power, 2. TCC, 3. Adfutec, 4. Takenaka Co.)

Keywords:

Clearance,NR,BWR,Concrete,Radioactivity Concentration,Secondary Contamination,penetration contamination,Carbon-14

Based on the contamination status of underground concrete in a BWR reactor building, C-14 and Co-60 are identified as the target radionuclides for evaluation. The depth profiles of both nuclides remain unclear; therefore, additional investigations will be conducted to clarify their concentration distributions and migration mechanisms. For C-14, a soft beta emitter, activity concentration will be determined using either the average activity concentration method or representative sampling units. A key challenge is establishing a method to define the boundary between clearance and non-radioactive waste (NR) in the depth direction. In particular, since C-14 also exists naturally, it is essential to define an appropriate detection limit to enable accurate assessment of the contamination range based on measurements.