Colloquium at NH group of Kyoto Univ.

Colloquium
of NH group, Kyoto Univ.
Paper introduction of:
Cosmic-ray muon radiography
of UO2 fuel assembly
T.Sugita et al., Journal of Nuclear Science and Technology 51, 7-8 (2014) 1024-1031
Toshiyuki Gogami
2015/2/23
再稼働しつつある原発
3.11  The accident of Fukushima NPP
Need information of melted fuel
for decommissioning of reactor
Difficult to access due to too high radiation level
Muon radiography
ミュオン透過法による炉内調査の開始‼
IRID (技術研究組合国際廃炉研究開発機構) R&D topics; 2015/2/12
Muon radiography
H.K.M.Tanaka et al., Earth Planets Space 62 (2010) 119-129
1. Transmission method
[ Energy loss  Stop ]
Mane, Egyptian pyramid, temple gate, volcano, caverns etc.
2. Scattering (displacement) method
[ Coulomb scattering  Scattering angle (displacement) ]
Invented at Los Alamos National Laboratory
At igh- emperature engineering est eactor (HTTR)
Transmission method
K.Takamatsu et al., Annals of Nuclear Energy 78 (2015) 166-175
At igh- emperature engineering est eactor (HTTR)
Transmission method
K.Takamatsu et al., Annals of Nuclear Energy 78 (2015) 166-175
Scattering method
Depending on the radiation length !!
𝐿𝑖 = 𝑑𝑖 tan 𝜃𝑖 (1 + tan 𝜃𝑖0 )
Paper which will be introduced
Toshiba Nuclear Critical Assembly
Experimental setup
C.L.Morris et al., Applied Physics Letters 104 (2014) 024110
30 days of data taking
MMT2
MMT1
Mini Muon Tracker (MMT) system
576 sealed drift tubes (5 cm diameter, 0.9 mm aluminum wall)
1.2 m length
xxyyxxyyxxyy (12 layers)
Cross section of NCA obtained by
the scattering method
Results
±2 cmで一致
Result comparison
with Geat4 simulation
Application for Fukushima Daiichi
10 m
10 m
Geant4 simulation model
Challenge for the high rate
gamma-ray background
1000 μSv/h
20 μSv/h
10 m
10 m
7.5 cm thickness steel
expects to be needed.
FPGA trigger
 50 μSv/h
Geant4 simulation model
Results of the simulation
50% melted core + 60 cm diameter debris
 Clearly seen !!
Summary
Muon radiography
• Can be used for nuclear reactor investigation
with resolution of 3 cm.
• Investigation of Fukushima Daiichi
• Transmission method (1号機、2015/2-)
• Scattering method (2号機、2015/10-)

Download Report