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Shimizu, Yasuyuki; Makino, Risa; Mukai, Yasunobu; Ishiyama, Koichi; Kurita, Tsutomu; Nakamura, Hironobu
Dai-37-Kai Kaku Busshitsu Kanri Gakkai Nihon Shibu Nenji Taikai Rombunshu (CD-ROM), 9 Pages, 2017/02
no abstracts in English
Nakamura, Hironobu; Shimizu, Yasuyuki; Makino, Risa; Mukai, Yasunobu; Ishiyama, Koichi; Kurita, Tsutomu; Ikeda, Atsushi*; Yamaguchi, Katsuhiro*
Proceedings of INMM 57th Annual Meeting (Internet), 9 Pages, 2016/07
Regarding the Integrated Safeguards (IS) in Japan, the implementation of IS has been started on September 2004, and the concept has been introduced to the JNC-1 facilities since August 2008. Then, random interim inspection with short notice and reducing person-days of inspection (PDI) was introduced instead of traditional scheduled IIV in order to improve deterrence of the nuclear material diversion with timeliness goal. And it was agreed that it should be evaluated and reviewed because RII was designed when inter-campaign. In JAEA, we decided to restart PCDF campaign to reduce potential safety risks of reprocessing facilities. To adopt the RII scheme to the process operation in campaign, JAEA proposed a new scheme to JSGO and IAEA without increasing PDI and reducing detection probability. As a result of the discussion, it was agreed and successfully introduced since March 2014. The new scheme for PCDF consists of scheduled inspection (fixed-day RII), reduction of estimated material for the verification, implementation of remote monitoring with data provision, improvement of operational status check list, introduction of NRTA and MC&A data declaration with timeliness. Though the operator's workloads for information provision were increased, we could manage to balance IS requirement with implementation of our operation successfully. This contribution was helped to safeguards implementation and our operation for 2 years.
Sekine, Megumi; Matsuki, Takuya; Tanigawa, Masafumi; Tsutagi, Koichi; Mukai, Yasunobu; Shimizu, Yasuyuki; Nakamura, Hironobu; Tomikawa, Hirofumi
Proceedings of INMM 57th Annual Meeting (Internet), 9 Pages, 2016/07
The International Atomic Energy Agency (IAEA) has proposed in its long-term research and development plan, development of a real-time measurement technology to monitor and verify nuclear material movement continuously as part of an advanced approach to effectively and efficiently conduct safeguards for reprocessing facilities. In the reprocessing plant, since solutions containing both Pu and FP exist, a new detector development project to monitor Pu with FP is being carried out from 2015 to 2017. This project is mainly conducted in the High Active Liquid Waste Storage (HALWS) in Tokai Reprocessing Plant (TRP). In this paper, an overview of the technology development, simulation results of preliminary evaluation of the characteristics of radiation emitted from the HALW tank at TRP, and the future research plan are presented.
Makino, Risa; Swinhoe, M. T.*; Suzuki, Hisanori; Ikeda, Atsushi*; Menlove, H. O.*; Shimizu, Yasuyuki; Nakamura, Hironobu
Kaku Busshitsu Kanri Gakkai (INMM) Nihon Shibu Dai-35-Kai Nenji Taikai Rombunshu (Internet), 9 Pages, 2015/01
The Inventory Verification Sample system (INVS) is a non-destructive assay system for samples to quantify the Pu amount in Pu nitrate solutions and MOX with 31.3% of counting efficiency. It has been used for IAEA verification measurement for many years at the Plutonium Conversion Development Facility for the samples taken at the timing of PIV etc. as a partial defects verification system (uncertainty: about 3-5%). If the measurement uncertainty can be improved (to 
1%), it is expected that the usage can be extended to the operator's own measurements in MC&A to reduce the number of destructive analyses. In order to improve the measurement uncertainty for solution samples, after optimization of detector parameter and sample position, we conducted 3 different types of calibration method that is passive calibration curve, known-
and multiplicity method to achieve the target uncertainty. To perform calibration and control the measurement quality, MOX fuel pellets with known Pu amount are fabricated and used. In the range of concentration of typical solution samples, we could confirm good correlations between measured doubles and 
Pu effective mass in the three methods. Especially, it was confirmed that the conventional calibration curve method could meet our target uncertainty (1%).
Kimura, Takashi; Shimizu, Yasuyuki; Yamazaki, Katsuyuki; Endo, Yuji; Nakamura, Hironobu
Kaku Busshitsu Kanri Gakkai (INMM) Nihon Shibu Dai-34-Kai Nenji Taikai Rombunshu (Internet), 8 Pages, 2013/10
no abstracts in English
Shimizu, Yasuyuki; Yamazaki, Katsuyuki; Kimura, Takashi; Endo, Yuji; Nakamura, Hironobu
Proceedings of INMM 54th Annual Meeting (CD-ROM), 7 Pages, 2013/07
Japanese regulation of reprocessing safety and security was revised in March 2012, and almost all requirements except for nuclear material accountancy and control described in the INFCIRC225/rev.5 are included into the regulation. We have many things to do to meet the requirements within 2 years pursuant to the regulation. Separately from the revised regulation, we think that utilizing the process monitoring data not only for the safety control but also for the nuclear material security would be useful in establishing more effective and efficient nuclear material security. Since we observe the process monitoring data to confirm the operational condition including unusual change for the safety purpose, it is though that the various alarm information through the process monitoring data help to detect the risk of sabotage and unauthorized removal. As future challenge, we would like to establish a possible method of utilizing the process monitoring data in combination with the physical protection to make it possible to give more effective and efficient nuclear material security.
Suzuki, Yutaka; Kuno, Takehiko; Nemoto, Hirokazu*; Okano, Masanori; Goto, Yuichi; Igarashi, Kazuto*; Shimizu, Yasuyuki; Suda, Shizuka; Yamada, Keiji; Watahiki, Masaru
no journal, ,
no abstracts in English
Tokoro, Hayate; Suzuki, Satoshi*; Miyoshi, Ryuta; Sakurai, Yasuhiro; Matsuki, Takuya; Tsutagi, Koichi; Sekine, Megumi; Shimizu, Yasuyuki; Nakamura, Hironobu
no journal, ,
We inserted a newly designed and manufactured thruster into the guide tube of the high active liquid waste storage cell for inspection in the Tokai Reprocessing Plant and measured the dose rate inside the cell. The dose rate distribution measurements using thruster is an unprecedented experiment, we checked job safety, operability of an equipment and relationship between insert distance of dosimeter and measurement position by using isometric scale mock-up equipment in advance. As a result, we implemented dose rate distribution measurement test inside the cell.
Nakamura, Hironobu; Kitao, Takahiko; Shimizu, Yasuyuki; Takeda, Seiichi; Yamaguchi, Katsuhiro*
no journal, ,
In order to determine the decommissioned status in the IAEA safeguards, JAEA attends the expert meeting held in IAEA to share the lessons learned and/or best practices. In the domestic examples, we can share a few examples in the decommissioning of experimental reactors, unfortunately, since there is no example in the bulk handling facilities (the facility which amount of nuclear material is determined by the measurement) such as reprocessing, MOX fabrication and centrifuge enrichment, based on the situation of nuclear material and dismantling of important process equipment (i.e. no reprocessing capability) in the decommissioning plan, after the confirmations that remaining nuclear materials is recovered and transferred to other facilities, and no process capability is established, are completed, it is concluded that it is necessary to terminate safeguards and nuclear material accountancy. In this report, we summarized the proposals as subjects such as change of material balance area or implementation of material balance evaluation by the decommissioning. we hope that the proposals is helped to determine the decommissioned status in the IAEA safeguards.
Nakamura, Hironobu; Kitao, Takahiko; Shimizu, Yasuyuki; Takeda, Seiichi; Yamaguchi, Katsuhiro*
no journal, ,
Based on the DIQ guideline discussed and summarized at the 1st consultancy meeting, since JAEA made an example of DIQ for the reprocessing considering the decommissioning stages as Japan's task, we explain the contents and submit it to IAEA in the 2nd consultancy meeting. Basically, as the information regarding decommissioning stage, date of decommissioned, facility decommissioning plan, nuclear material recovery and removing or rendering inoperable of "essential equipment" with example are additionally described in the DIQ. We hope that this material could be helped to make a reprocessing DIQ (PUREX) in the world.
Shimizu, Yasuyuki
no journal, ,
Participating the 1st Consultancy meeting "Safeguards guidelines for post-accident facilities and associated waste management facilities" in order to share the past TRP operational experience regarding the safeguards for waste management and discuss with experts for establishing the safeguards guideline for post-accident facilities and associated waste management facilities.
Kato, Akane; Shimizu, Yasuyuki; Kitao, Takahiko; Nakamura, Hironobu
no journal, ,
Tokai Reprocessing Plant (TRP) had reprocessed 1,140 tons spent fuel (SF) since 1977 to 2007, and the Post-Fukushima safety regulations triggered TRP to decide to shut the plant and shifted to decommissioning phase from 2018. The estimated entire duration of TRP decommissioning is expected to be 70 years. The early stage of the TRP decommissioning includes the recovery of remaining nuclear material in the process and transferring those nuclear material between multiple facilities ("Flush-out"), vitrification activity of remaining high active liquid waste and transferring collected nuclear material to the storage facility, and the management of radioactive waste. The Flush-out is as the first step of TRP decommissioning and it is in progress since July 2022 for two years prior to the start of serious decommissioning activities such as the decontamination, dismantling/removing the process. Since these decommissioning activities are unexperienced challenges and they are not related to "SF reprocessing", therefore ensuring appropriate nuclear material control and accountancy (MC&A) and the transparency in terms of safeguards verification implemented by IAEA are important role as the operator. In this paper, we report about the residual nuclear material recovery process and relevant MC&A and safeguards measures in the Flush-out as the first stage of TRP decommissioning project.
Nakamura, Hironobu; Takeda, Seiichi; Shimizu, Yasuyuki; Takeda, Hideyuki; Aoki, Rie; Shirafuji, Masaya; Kitao, Takahiko; Miyaji, Noriko
no journal, ,
In the consultancy meeting "Safeguards Guidelines for post-accident facilities and associated waste management facilities" held in IAEA, decommissioning activities, and the relevant safeguards activities in TRP/PCDF are reported. In general, the facility after accident with access limitation, operator decides to conduct decommissioning. Therefore, our report regarding the decommissioning plan and the relevant safeguards activities are very helpful to be considered. The nuclear material remove and waste management (storage/treatment) are essential work in the normal accessible facility as well as post-accident facility. Otherwise, in the case of post accident facility, alternative safeguards measures is required according to the access situation because normal safeguards activities might not be taken appropriately. In this report, we would present that outline of decommissioning plan in the TRP/PCDF and the relevant safeguards and nuclear material accountancy.