Phase 2 of Monju decommissioning, 4; Assessment of contamination distribution of "Monju"

Hanaki, Shotaro  ; Mashimo, Ryutaro; Nanri, Tomohiro ; Hayashi, Hirokazu 

The assessment of contamination distribution evaluates the type, radioactivity and distribution of radioactive materials remaining in the facility for the purpose of reducing the exposure of radiation workers and the surrounding public, formulating dismantling and removal methods and procedures, and evaluating the amount of radioactive waste generated during dismantling and removal work. In Monju, some structural materials around the reactor and primary sodium have been activated, and radioactive materials remain as secondary contamination on the inner surfaces of equipment and piping in the primary cooling system, although the total amount of radioactive materials is small. This presentation provides an overall overview of the assessment and the results of the assessment carried out in the first phase.