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Konno, Chikara; Kochiyama, Mami; Hayashi, Hirokazu
Proceedings of 30th International Conference on Nuclear Engineering (ICONE30) (Internet), 9 Pages, 2023/05
JENDL-5 released in 2021 includes enough cross section data for neutron activation calculations. Thus we have produced ORIGEN and ORIGEN-S libraries from JENDL 5. We also produced the similar libraries from JENDL/AD-2017 for comparison. Analyses of the JPDR decommissioning data with these libraries demonstrated that the libraries had no problem.
Konno, Chikara; Kochiyama, Mami; Hayashi, Hirokazu
JAEA-Conf 2021-001, p.132 - 137, 2022/03
A SCALE6.2 ORIGEN library was produced with the AMPX-6 code from JENDL Activation Cross Section File for Nuclear Decommissioning 2017 (JENDL/AD-2017). For validation of the libraries, JPDR activation calculation was performed with ORIGEN and the libraries, which demonstrated the library had no problem.
Izumo, Sari; Hayashi, Hirokazu; Nakata, Hisakazu; Amazawa, Hiroya; Motoyama, Mitsushi*; Sakai, Akihiro
JAEA-Technology 2018-018, 39 Pages, 2019/03
JAEA-Technology-2018-018.pdf:2.8MB
JAEA has planed the near surface disposal of LLW generated from research, industrial, and medical facilities. Maximum radioactivity concentration of each waste and total radioactivity of disposed wastes are needed to be less than the permitted values in the license of disposal facility. Thus, it is important not to evaluate the radioactivity of each waste in unduly conservative ways so as to dispose of the total amount of the waste that is originally planned. Accordingly, the detection limit is required to be as low as the clearance level for the very low level radioactive waste planned to be disposed of trench-type. In this report, the feasibility of the non-destructive assay method is studied by model calculations for gamma emitters. It is confirmed that the detection limit less than the clearance level can be achieved as regards the box type metal container that is difficult to measure. This report summarizes the requirements for the non-destructive measuring equipment.
Hayashi, Hirokazu; Izumo, Sari; Nakata, Hisakazu; Amazawa, Hiroya; Sakai, Akihiro
JAEA-Technology 2018-001, 66 Pages, 2018/06
JAEA-Technology-2018-001.pdf:4.12MBJAEA-Technology-2018-001(errata).pdf:0.54MB
It is necessary to establish evaluation methodology of radioactivity concentrations of each radionuclide in waste packages for operation of the Near-surface Trench disposal and Sub-surface Pit disposal facility in near future, which has been preparing for low-level radioactive wastes generated from research facilities in JAEA. The radionuclides containing in waste packages generated from both JRR-2 and JRR-3, which are H-3, C-14, Cl-36, Co-60, Ni-63, Sr-90, Nb-94, Tc-99, Ag-108m, I-129, Cs-137, Eu-152, Eu-154, U-234, U-238, Pu-239+240, Pu-238+Am-241, Cm-243+244, were evaluated their density based on radiochemical analysis data, and the Evaluation Methodology of the Radioactivity Concentration such as Scaling Factor method and mean activity concentration method was studied in this report.
Nakata, Hisakazu; Hayashi, Hirokazu; Amazawa, Hiroya; Sakai, Akihiro
JAEA-Technology 2017-031, 41 Pages, 2018/01
JAEA-Technology-2017-031.pdf:5.27MB
JAEA plans to install disposal facilities for radioactive waste arising from research institutes. It must meet the technical standards specified in the relevant rule. One technical standard is that the disposal facilities shall be performance so as not to be left with the voids after the backfilling with soil. Additionally, the rule also requires this radioactive waste be enclosed in a container in which no harmful voids remain. In order to contribute to the development of a method that adapts the disposal facilities to these technical standards, JAEA adopts a waste conditioning artifice that aims for reducing a quantity of voidage in each waste container by a vibration filling method using sandy soil, providing with average void ratios inside the disposal facilities being adequately controlled. In this reports, filling property tests are conducted in the light of filling sand characteristics, types of metal waste and vibration conditions.
Soejima, Goro; Iwai, Hiroki; Nakamura, Yasuyuki; Hayashi, Hirokazu; Kadowaki, Haruhiko; Mizui, Hiroyuki; Sano, Kazuya
Proceedings of 25th International Conference on Nuclear Engineering (ICONE-25) (CD-ROM), 5 Pages, 2017/07
no abstracts in English
Hayashi, Hirokazu; Okada, Shota; Izumo, Sari; Hoshino, Yuzuru; Tsuji, Tomoyuki; Nakata, Hisakazu; Sakai, Akihiro; Amazawa, Hiroya; Sakamoto, Yoshiaki
Proceedings of 2017 International Congress on Advances in Nuclear Power Plants (ICAPP 2017) (CD-ROM), 7 Pages, 2017/04
A near surface disposal for low-level radioactive waste (LLW) generated from commercial nuclear power plants (NPP) is operating in Japan. However, the disposal of LLW from other nuclear facilities and radioisotope utilization facilities has not yet been implemented. Japan Atomic Energy Agency (JAEA) plans to implement the near surface disposal. In order to be disposed of these wastes, it must be confirmed by the regulator that each waste package (radioactive waste solidified with filling materials, such as cement, in a container by a regulated method is termed a waste package) conforms to technical standards that aim for safe disposal. JAEA has studied reasonable confirmation methods to demonstrate the conformity of the waste package to the technical standard as NPP operators have studied it. This report describes the outline of our activities focused on development of the confirmation method applicable to radioactive wastes from research facilities.
Totsuka, Masayoshi; Kurosawa, Ryohei*; Sakai, Akihiro; Nakata, Hisakazu; Hayashi, Hirokazu; Amazawa, Hiroya
JAEA-Technology 2017-001, 40 Pages, 2017/03
JAEA-Technology-2017-001.pdf:2.24MB
Japan Atomic Energy Agency is planning for the near surface disposal of low level radioactive wastes generated from research, industrial and medical facilities industry in Japan. This document provides the values of radioactivity concentrations equivalent to dose criterion for trench-type disposal. These values are derived based on the safety assessment for ground water scenarios by using a model which describes the release of radionuclides from wastes to a cover soil caused by elution. These concentrations are compared with the one calculated by a model that describes the nuclide release mechanisms as solid-liquid partitioning equilibrium. Additionally, the change in the concentrations is evaluated when the amount of water percolating into a disposal facility varies.
Hayashi, Hirokazu; Soejima, Goro; Mizui, Hiroyuki; Sano, Kazuya
Proceedings of 23rd International Conference on Nuclear Engineering (ICONE-23) (DVD-ROM), 7 Pages, 2015/05
In the Fugen Nuclear Power Plant, we are going to conduct appropriate classification of the waste according to the contamination level of the material of the plant, to reduce the amount of radioactive waste and to promote dismantling work rationally and efficiently. For this reason, we are going to apply the clearance system to the dismantled material generated from dismantling work of the turbine system, and to reduce the radioactive waste amount as much as possible. In order to operate the clearance system properly, the target nuclides need to be selected accurately, and the evaluation method of them should be established. The assessment was conducted as follows.
Otani, Hiroshi; Hayashi, Hirokazu; Kawagoe, Shinji; Hamada, Nobuyuki; Nakamura, Yasuyuki
JAEA-Review 2011-026, 41 Pages, 2011/07
JAEA-Review-2011-026.pdf:7.38MB
In planning and carrying out our decommissioning technical development, "Technical special committee on Fugen decommissioning", which consists of the members well-informed, is established, aiming to make good use of Fugen as a place for technological development which is opened inside and outside the country, as the central point in the energy research and development base making project of Fukui prefecture, and to utilize the outcome in our decommissioning to the technical development effectively. This report compiles presentation materials "Current Situation of Fugen Decommissioning", "Preparatory Situation for Operation of Clearance System", "Examined Situation of Nuclear Reactor Dismantlement Technology" of the 23rd Technical special committee on Fugen decommissioning which held on March 11, 2011.
Kutsuna, Hideki; Matsumori, Akira*; Izumi, Masanori; Hayashi, Hirokazu; Higashiura, Norikazu
JAEA-Review 2011-025, 43 Pages, 2011/07
JAEA-Review-2011-025.pdf:2.84MB
In planning and carrying out our decommissioning technical development, "Technical special committee on Fugen decommissioning", which consists of the members well-informed, is established, aiming to make good use of Fugen as a place for technological development which is opened inside and outside the country, as the central point in the energy research and development base making project of Fukui prefecture, and to utilize the outcome in our decommissioning to the technical development effectively. This report compiles presentation materials "Current Situation of Fugen Decommissioning", "Radioactive Corrosion Products (CP) Decontamination Experiment with Heavy Water System Equipment", "Application of management data evaluation system to Fugen", "Preparatory Situation for Operation of Clearance System" of the 22nd Technical special committee on Fugen decommissioning which held on September 14, 2010.
Tezuka, Masashi; Mizui, Hiroyuki; Matsushima, Akira; Nakamura, Yasuyuki; Hayashi, Hirokazu; Sano, Kazuya; Nanko, Takashi; Morishita, Yoshitsugu
Proceedings of International Conference on Advanced Nuclear Fuel Cycle; Sustainable Options & Industrial Perspectives (Global 2009) (CD-ROM), p.2815 - 2821, 2009/09
FUGEN is a proto-type heavy water moderated, boiling light water cooled, pressure tube type reactor with 165MWe and has been shut downed on Mar. 2003. Following the approval of decommissioning program in 2008, stage of FUGEN was changed to the decommissioning of the facilities. The program consists of following four periods; (1) Spent fuel transportation, (2) Periphery facilities dismantlement, (3) Reactor dismantlement and (4) Building demolition. It is expected that the whole decommissioning will be completed until 2028. As a part of the work in the spent fuel transportation period, the main steam system and the feeder water system etc. are being dismantled in the turbine building. The remaining tritium in the heavy water system is also being removed for facilitating the dismantlement of the heavy water system. Moreover, method on dismantlement of the reactor core is being studied with considering the process under the water for the radiation shielding and the dust suppression.
Kitamura, Koichi; Hayashi, Hirokazu; Morishita, Yoshitsugu; Tanji, Kazuhiro*
Hoshasen, 34(1), p.53 - 63, 2008/01
It is very important to evaluate radioactive inventory and an amount of radioactive waste accurately for both the planning and the safety assessment on Fugen's decommissioning. Fugen had carried out various radioactive inventory investigations, activation evaluations by materials sampling, neutron measurements, contamination evaluation by investigation of radiation control records, etc. since operation period because Fugen uses heavy water as moderator and its core structure is different from that of LWR. And then, radioactive inventory was evaluated using those investigation data. Moreover, an amount of radioactive waste was estimated by the classification for the radioactive waste disposal based on the evaluated radioactive inventory results. This paper is intended to introduce the evaluation methods and results of the radioactive inventory and estimation of an amount of radioactive waste for Fugen.
Kato, Yuko; Umebayashi, Eiji; Okimoto, Yutaka; Okuda, Eiichi; Takayama, Koichi; Ozawa, Takayuki; Maeda, Seiichiro; Matsuzaki, Masaaki; Yoshida, Eiichi; Maeda, Koji; et al.
JAEA-Research 2007-019, 56 Pages, 2007/03
JAEA-Research-2007-019.pdf:6.79MB
In order to resume the System Startup Test (SST) of Monju, replacement fuel have to be loaded in exchange for some of initial fuel now loaded in the core to compensate core reactivity lost by decay of Pu-241 in them. The replacement fuel were being stored either in sodium in an ex-vessel storage tank or in air in a storage rack for about 10 years since their fabrication. The initial fuel were irradiated during the SST which was suspended in the end of 1995 and then stayed being loaded in the sodium-circulated core. As this long-term storage and loading may deteriorate mechanical integrity of the assemblies, a study has been made thoroughly on its thermal-hydraulic, structural and material effects on them that might be caused by irradiation in the core, sodium and mechanical environment. The study has shown that the mechanical integrity of them is well maintained even with this long-term storage and loading.
Ota, Hirokazu*; Ogata, Takanari*; *; ; Hayashi, Hideyuki; ;
JNC TY9400 2001-015, 40 Pages, 2001/03
JNC-TY9400-2001-015.pdf:1.62MB
no abstracts in English
Yokota, Wataru; Nara, Takayuki; Arakawa, Kazuo; Nakamura, Yoshiteru; Fukuda, Mitsuhiro; Agematsu, Takashi; Okumura, Susumu; Ishibori, Ikuo; Tachikawa, T.*; *; et al.
Proceedings of 13th International Conference on Cyclotrons and Their Applications, p.336 - 339, 1993/00
no abstracts in English
Arakawa, Kazuo; Nakamura, Yoshiteru; Yokota, Wataru; Fukuda, Mitsuhiro; Nara, Takayuki; Agematsu, Takashi; Okumura, Susumu; Ishibori, Ikuo; *; Tanaka, Ryuichi; et al.
Proceedings of 13th International Conference on Cyclotrons and Their Applications, p.119 - 122, 1993/00
no abstracts in English
Tachikawa, T.*; *; *; *; Nakamura, Yoshiteru; Yokota, Wataru; Fukuda, Mitsuhiro; Kamiya, Tomihiro; Agematsu, Takashi; Nara, Takayuki; et al.
Proceedings of the International Conference on Evolution in Beam Applications, p.270 - 274, 1992/00
no abstracts in English
