Gamma emission tomography measurements of fuel assemblies at the Halden reactor

Conference · Fri Jul 01 04:00:00 EDT 2016

OSTI ID:22765240

Holcombe, S. ^[1]; Andersson, P. ^[2]

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1. Institute for Energy Technology - OECD Halden Reactor Project, Halden (Norway)
2. Division of Applied Nuclear Physics, Uppsala University, Uppsala (Sweden)

Gamma emission tomography measurements have been performed at the Halden Reactor Project using a dedicated instrument, which utilizes a high-resolution gamma-ray detector allowing for spectroscopic analysis of the measurement data. Measurements have been performed on two fuel assemblies consisting of 9 and 13 rods, respectively, in order to characterize the rod-wise radioactive source distribution (i.e. fission and activation products) within the fuel. The 9-rod fuel assembly consisted of five fuel rods at 50 MWd/kgUO{sub 2} and four fuel rods at 26 MWd/kgUO{sub 2}, where all rods had cooled for approximately 22 years at the time of measurement. The rods in the 13-rod assembly all had a burnup of ∼4.5 MWd/kgUO{sub 2}, and cooled for approximately 1.5 years at the time of measurement. In this paper, the tomographic data was reconstructed using the Filtered Backprojection technique, where no consideration to gamma-ray attenuation in the fuel was given. Due to the varying burnup and cooling times between the assemblies, the spectroscopic data also varied between the respective sets of measurements. The high-resolution detector used in the measurements allowed for tomographic reconstruction of many gamma-ray peaks corresponding to various fission products and activation products present in the fuel and structural materials. For instance the gamma tomography technique has shown rod-wise variation in the contents of fission products between the high-burnup and low-burnup rods. The rod-internal distribution of fission products was also observed where the volatile fission product {sup 137}Cs is observed to have migrated to the outer pellet surface in fuel rods in the 9-rod assembly, and where the gaseous fission product {sup 85}Kr is observed to have a uniform distribution in each fuel rod's gas plenum.

• Research Organization: American Nuclear Society - ANS, 555 North Kensington Avenue, La Grange Park, IL 60526 (United States)
• OSTI ID: 22765240
• Country of Publication: United States
• Language: English

Related Subjects

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY
ATTENUATION
BUILDING MATERIALS
BURNUP
CESIUM 137
COOLING
DISTRIBUTION
FISSION PRODUCT RELEASE
FISSION PRODUCTS
FUEL ASSEMBLIES
FUEL PELLETS
FUEL RODS
GAMMA RADIATION
GAMMA SPECTROSCOPY
HBWR REACTOR
KRYPTON 85
NUCLEAR FUELS
RADIATION SOURCES
RESOLUTION
TOMOGRAPHY