2020/05/12 by Hirofumi Fujii, Fujii, Hirofumi, Kazuhiko Hara +46
Physics and Astronomy · #FOS: Physical sciences #Instrumentation and Detectors (physics.ins-det) #Particle Detector Development and Performance #Particle physics theoretical and experimental studies #Radiation Detection and Scintillator Technologies #physics.ins-det
paper · pdf · doi:10.48550/arxiv.2005.05585
11 figures and 2 tables
arxiv created 2020/05/12 · openalex publication_date 2020/05/12 · arxiv updated 2020/05/13 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We have investigated the status of the nuclear debris in the Unit-2 Nuclear Reactor of the Fukushima Daiichi Nuclear Power plant by the method called Cosmic Muon Radiography. In this measurement, the muon detector was placed outside of the reactor building as was the case of the measurement for the Unit-1 Reactor. Compared to the previous measurements, the detector was down-sized, which made us possible to locate it closer to the reactor and to investigate especially the lower part of the fuel loading zone. We identified the inner structures of the reactor such as the containment vessel, pressure vessel and other objects through the thick concrete wall of the reactor building. Furthermore, the observation showed existence of heavy material at the bottom of the pressure vessel, which can be interpreted as the debris of melted nuclear fuel dropped from the loading zone.