Clearance of concrete generated from modification activities of JRR-3; Results for measuring and evaluating radioactivity concentration

Ogoshi, Yurie; Satoyama, Tomonori ; Kishimoto, Katsumi ; Nanri, Tomohiro ; Suzuki, Takeshi; Tomioka, Osamu ; Takaizumi, Hirohide*; Kanno, Tomoyuki*; Maruyama, Tatsuya*

At Nuclear Science Research Institute, clearance works for about 4,000 tons of extremely low-level radioactive concrete debris, which were generated from the modification activities of JRR-3 from FY 1985 to FY 1989 and stored in the waste storage facility NL, carried out. First of this clearance works, method for measuring and evaluating radioactivity concentration was approved by Minister of MEXT on July 25, 2008. And then, clearance works were started from FY 2009. Measuring and evaluating radioactivity concentration was achieved by using the approved method, and was confirmed by government. And then, clearance works were completed in FY 2014. The clearance concrete was recycled as a material for restoration works of the 2011 off the Pacific coast of Tohoku Earthquake. This report summarizes the results of measuring and evaluating radioactivity concentration, achievement of confirmation by government, recycling of cleared concrete and cost for clearance works.