Comparison of the observed Fukushima Dai-Ichi Unit 2 debris with simulated debris from the CLADS-MADE-01 control blade degradation test

In February 2019, TEPCO and TOSHIBA designed a robot that can handle the debris, performed a trial investigation of primary containment vessel (PCV) of the Fukushima Dai-Ichi (1F) Unit 2 and published a video. The video contained lots of valuable information which can be compared with results of BWR control blade degradation tests recently performed in Japan Atomic Energy Agency (JAEA). During the test under postulated 1F Unit 2 simulated conditions a complex behaviour of the test sample with the formation of mostly three types of debris was observed. Possible mechanisms governing the 1F Unit 2 debris formation and possible ways of their relocation are discussed. (author)