Academic Articles | |||||
Regular Paper | Vol.11 No.1 (2019) p.46 - p.64 | ||||
X-band electron LINAC-based compact neutron source for nuclear debris on-site screening using short-distance neutron resonance transmission analysis |
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Yudhitya KUSUMAWATI1,*, Issei OZAWA1, Yuki MITSUYA1, Tomooki SHIBA2 and Mitsuru UESAKA1 |
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1 Department of Nuclear Engineering and Management, School of Engineering, The University of Tokyo, Tokyo 113-8654, Japan 2 Integrated Support Center for Nuclear Nonproliferation and Nuclear Security (ISCN) and Collaborative Laboratories for Advanced Decommissioning Science (CLADS), Japan Atomic Energy Agency, Ibaraki 319-1184, Japan |
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Abstract | |||||
Unaccountable nuclear fuel debris is subject to nuclear safeguards and criticality safety, and their removal is one of the decommissioning activities of the TEPCO Fukushima Daiichi Nuclear Power Plant (The 1F). In order to significantly contribute to efficient debris retrieval, an on-site nuclear debris screening system consisted of non-destructive analysis using both X-ray and neutron source is being developed. By realizing a compact pulsed neutron source system from a 3.95 MeV X-band electron LINAC coupled with tungsten and beryllium as photon and neutron converters respectively, on-site short-distance neutron resonance transmission analysis (NRTA) can be performed to confirm the existence of U/Pu in a nuclear debris sample. Experiment result shows that neutron TOF energy spectrum up to 70 eV with 4% energy resolution can be measured within only 2.5 m of neutron flight path through a 3He proportional counter. NRTA experiments using mixed model samples indicate that multiple resonance peaks in the neutron energy spectrum up to 20 eV, where resonance peaks of major U/Pu isotopes fall within this range, can be simultaneously observed. The proof-of-principle experiment was successfully performed. Short-distance NRTA would be an important complementary method for database calibration of polychromatic X-ray CT system of nuclear debris, which can provide estimation of U/Pu distribution data necessary for nuclear debris activity mapping of The 1F reactor core area. | |||||
Keywords | |||||
isotope identification; neutron resonance; neutron source; on-site measurement; time of flight; transmission; X-band | |||||
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