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Mukai, Yasunobu; Nakamichi, Hideo; Kobayashi, Daisuke; Nishimura, Kazuaki; Fujisaku, Sakae; Tanaka, Hideki; Isomae, Hidemi; Nakamura, Hironobu; Kurita, Tsutomu; Iida, Masayoshi*; et al.
Proceedings of 2017 International Congress on Advances in Nuclear Power Plants (ICAPP 2017) (CD-ROM), 8 Pages, 2017/04
TRP has stored the plutonium in solution state for long-term since the last PCDF operation in 2007 was finished. After the great east Japan earthquake in 2011, JAEA had investigated the risk against potential hazard of these solutions which might lead to make hydrogen explosion and/or boiling of the solution accidents with the release of radioactive materials to the public when blackout. To reduce the risk for storing Pu solution (about 640 kg Pu), JAEA planned to perform the process operation for the solidification and stabilization of the solution by converted into MOX powder at PCDF in 2013. In order to perform PCDF operation without adaption of new safety regulation, JAEA conducted several safety measures such as emergency safety countermeasures, necessary security and safeguards (3S) measures with understanding of NRA. As a result, the PCDF operation had stared on 28th April, 2014, and successfully completed to convert MOX powder on 3rd August, 2016 for about 2 years as planned.
Mukai, Yasunobu; Nakamura, Hironobu; Tanigawa, Masafumi; Nakamichi, Hideo; Umino, Yoshinori; Fujisaku, Sakae; Kimura, Takashi; Kurita, Tsutomu
Kaku Busshitsu Kanri Gakkai (INMM) Nihon Shibu Dai-36-Kai Nenji Taikai Rombunshu (Internet), 9 Pages, 2015/12
When the unauthorized removal of nuclear materials (NM) from glovebox (GB) by an insider happens, it needs to be detected and reported immediately. In this time, for utilization of the security counterplan, the feasibility of a new detection concept for the unauthorized removal was investigated with implementation of several experiments considering actual GB operation. In general, the detection method using radiation monitor is thought of easily. However, it is very difficult to distinguish between authorized NM movement during operation and the unauthorized removal. To solve this subject, JAEA focused on negative pressure monitoring of GB, and investigated a new detection concept combining the neutron and negative pressure monitoring. As a result of the experiments in small-scale GB, it was revealed that this new concept had the capability to detect the unauthorized removal and to alarm to central alarm station rapidly, and had the possibility to enhance the effectiveness of the current physical protection measures.
Nakamura, Hironobu; Tanigawa, Masafumi; Mukai, Yasunobu; Nakamichi, Hideo; Umino, Yoshinori; Fujisaku, Sakae; Kimura, Takashi; Kurita, Tsutomu
Proceedings of INMM 56th Annual Meeting (Internet), 8 Pages, 2015/07
In the MOX handling facilities, many types and amount of nuclear materials (NM) that are relatively easy to access are used in a GB. In order to prevent unauthorized removal of NM from the GB by an insider, based on the Japanese regulation which was referred from INFCIRC/225 Rev.5, the 2 person rule are being introduced at the area where NM handling GB are installed. As an example of usage of the security counterplan for the detection of unauthorized removal of NM, a new proposal of detection concept for the unauthorized removal by operators were investigated with implementation of several experiments considering actual GB operation. In general, it is considered that normal concept is to use radiation monitor (
or neutron) to detect the event by checking the variation of monitoring data. However, it is thought that distinguish between authorized NM movement during operation and the unauthorized removal (sample bag-out from GB) is very difficult. To solve this subject, JAEA studied and proposes a new concept about negative pressure monitoring in the GB in addition to the radiation monitoring. It is thought that the hybrid monitoring concept between pressure and radiation provides the detection alarm for it with central alarm station (CAS) accurately and rapidly with high integrity, and helps to complement current 2 person rule.
Mukai, Yasunobu; Nakamura, Hironobu; Fujisaku, Sakae; Kurita, Tsutomu; LaFleur, A. M.*; Menlove, H. O.*; Marlow, J. B.*
Kaku Busshitsu Kanri Gakkai (INMM) Nihon Shibu Dai-34-Kai Nenji Taikai Rombunshu (Internet), 9 Pages, 2013/10
In case of the Pu mass determination in scattered powder in a GB using Continuous Neutron Monitor (CNM) with totals, self-multiplication of neutron (M) and 
value are properly required to be set. M can be easily estimated by a simulation code, but it is very difficult to estimate value by such a simulation because interactions between ray generated from Pu and impurities are not consistent. Therefore, we tried to examine an estimation technique of value by direct measurement. As a result, by measuring the samples taken from the scattered powder using a multiplicity counter with a dual ring structure of He-3 tubes, we could confirm a good correlation between ring ratio (inner / outer ring count rates) and the values. Thus, we can estimate value in the powder directly by the ring ratio measurement. By applying this technique to CNM and designing a new detector with a double layer structure of neutron detection tubes, we had a prospect that CNM would be able to measure the Pu mass continuously.
spectrometry applied to product MOX powderHosoma, Takashi; Nakamura, Hironobu; Mukai, Yasunobu; Fujisaku, Sakae
Kaku Busshitsu Kanri Gakkai (INMM) Nihon Shibu Dai-28-Kai Nenji Taikai Rombunshu (CD-ROM), 8 Pages, 2007/00
For verification of MOX powder produced daily in a MOX conversion plant, it is expected to reduce uncertainty of NDA which enables bias defect verification and improves compatibility with plant operation. JAEA had studied conceptual design of such NDA in 2000 with DOE and there was a proposal to utilize analytical results of isotopic composition of the sources (plutonium nitrate) which were entirely verified by IAEA. The idea to determine weighing coefficients of the combination of the sources reproducing the peak ratios of measurable isotopes by HRGS was developed and confirmed using data obtained at PCDF and simulated HRGS data. It is possible to reduce uncertainty of HRGS to 1/2-1/3. For example, around 0.7% uncertainty of effective 
Pu ratio is realized, if HRGS achieves 2% uncertainty. It is sufficient to pick simply the latest four lots as the sources which were received to the facility at the time of measuring or verifying product MOX powder.
Fujisaku, Sakae; Mukai, Yasunobu; Isomae, Hidemi; Yoshimoto, Katsunobu
no journal, ,
no abstracts in English
Nakamura, Hironobu; Nakamichi, Hideo; Takaya, Akikazu; Shoji, Kaoru*; Matsumoto, Masaki; Fujisaku, Sakae; Yoshimoto, Katsunobu
no journal, ,
For the MOX conversion test by using plutonium nitrate solution that is recycled by Fugen MOX spent fuel, JAEA had performed temperature evaluation for plutonium solution receiving tank (annular shape), and had established the guideline of thermal effect by comparing the measured temperature with designed temperature.
Fujisaku, Sakae; Nakamura, Hironobu; Takaya, Akikazu; Nakamichi, Hideo; Matsumoto, Masaki; Shoji, Kaoru*; Yoshimoto, Katsunobu
no journal, ,
For the MOX conversion test by using plutonium nitrate solution that is recovered by Fugen MOX spent fuel, JAEA had perform the temperature evaluation for MOX powder and had established the guideline for thermal effect by comparing measured temperature with designed temperature.
Mukai, Yasunobu; Nakamura, Hironobu; Fujisaku, Sakae; Kurita, Tsutomu; Yoshimoto, Katsunobu; Hayashi, Hiroyuki*
no journal, ,
no abstracts in English
Nakamichi, Hideo; Hirono, Kenji*; Shoji, Kaoru*; Nakamura, Hironobu; Matsumoto, Masaki; Fujisaku, Sakae; Yoshimoto, Katsunobu
no journal, ,
In order to establish the conversion technology development test regarding MOX powder handling during transportation when high burn-up plutonium is used, temperature measurement on the canister in a transportation cask and powder property analysis were performed. As a result of the test, effective guideline of anticipated temperature on the canister could be obtained.
Umino, Yoshinori; Sudo, Katsuo; Fujisaku, Sakae; Yoshimoto, Katsunobu; Seya, Katsunori*
no journal, ,
no abstracts in English
Miyamoto, Masanori; Shirozu, Hidetomo; Morita, Minoru; Fujisaku, Sakae; Kurita, Tsutomu; Kimura, Yuichi; Kataoka, Satoshi; Seya, Katsunori*; Sasaki, Shunichi
no journal, ,
no abstracts in English