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JAEA Reports

Tritium removal of heavy water system and helium system in FUGEN

Takiya, Hiroaki; Kadowaki, Haruhiko; Matsushima, Akira; Matsuo, Hidehiko; Ishiyama, Masahiro; Aratani, Kenta; Tezuka, Masashi

JAEA-Technology 2020-001, 76 Pages, 2020/05

JAEA-Technology-2020-001.pdf:6.06MB

Advanced Thermal Reactor (ATR) FUGEN was operated for about 25 years, and now has been proceeding decommissioning after the approval of the decommissioning plan in Feb. 2008. The reactor, heavy water system and helium system are contaminated by tritium because of neutron absorption of heavy water, which is a moderator. Before dismantling these facilities, it is necessary to remove tritium from them for not only reducing the amount of tritium released to surrounding environment and the risk of internal exposure by tritium but also ensuring the workability. In first phase of decommissioning (Heavy Water and Other system Decontamination Period), tritium decontamination of the reactor, heavy water system and helium system started in 2008 and completed in 2018. This report shows the results of tritium decontamination of the reactor, heavy water system and helium system.

Journal Articles

Status of decommissioning of FUGEN Decommissioning Engineering Center

Takiya, Hiroaki; Aratani, Kenta; Awatani, Yuto; Ishiyama, Masahiro; Tezuka, Masashi; Mizui, Hiroyuki

Dekomisshoningu Giho, (59), p.2 - 12, 2019/03

FUGEN Decommissioning Engineering Center received the approval of the decommissioning program in 2008, and we have been progressing the decommissioning. The first phase of decommissioning (Heavy Water and Other system Decontamination Period) finished in May 2018, and FUGEN has entered into the second phase of decommissioning (Reactor Periphery Facilities Dismantling Period). This report outlines the results obtained in the first phase of decommissioning of FUGEN.

Journal Articles

Pipe cutting method at high radiation area in FUGEN

Takiya, Hiroaki; Ishiyama, Masahiro; Tezuka, Masashi; Kitayama, Naoki

Proceedings of International Conference on Dismantling Challenges; Industrial Reality, Prospects and Feedback Experience (DEM 2018) (Internet), 8 Pages, 2018/10

In FUGEN, we had isolated the reactor core by cutting pipes of the periphery systems (e.g. reactor cooling system, heavy water system, and helium system) between 2015 and 2017, as preparation for dismantling the reactor core and taking some samples from the reactor core structures. There are three issues to be solved at this isolation work; (1) to shorten the working time at high radiation area which is 1-5mSv/h at air and 10mSv/h at contact, (2) to prevent tritium spreading to working area at cutting work because tritium air is existing with 20-30Bq/cm$$^{3}$$ inside of the heavy water system and helium system, and (3) to minimize the influence of contaminated fume for the accurate radioactivity evaluation of reactor core structure. In this study, considering these problems, we discussed the method for cutting the pipes of heavy water system and helium system at the high radiation area and carried out the pipe cutting in the way.

Journal Articles

Evaluation of corrosion on generating tube in water tube boiler

Kawasaki, Ichio; Ishiyama, Toru; Usui, Masahiro*; Murakami, Toshinori*

Boira Kenkyu, (382), p.26 - 33, 2013/12

There are 4-boiler systems in Nuclear Fuel Cycle Engineering Laboratories. These has been operated in over 16 years. In one of them, the leakage that occurred at generating tube was found at Dec. 2011. The investigation of the leakage was carried out. The leaked generating tube was removed, and the part of leakage was cut off, and the deposit around the leakage was removed to analyze the cause of leakage. The analysis was carried out by SEM,EDX,WDX and XRD. etc. Elements of the deposit accumulated to surface of water drum are mainly O, Fe and S, and then many of component was sulfide. Therefore it seems that generating tube was corroded by sulfide. In future plan, operating method will be review to reduce the deposit, and check item will be selected to find the deposit earlier. This report was described about variously activity for the investigation and a future action.

Journal Articles

Beam study results with HBC stripping foils at the 3-GeV RCS in J-PARC

Yoshimoto, Masahiro; Yamazaki, Yoshio; Hayashi, Naoki; Yamamoto, Kazami; Saeki, Riuji; Hotchi, Hideaki; Saha, P. K.; Harada, Hiroyuki; Kawase, Masato; Ishiyama, Tatsuya; et al.

Proceedings of 1st International Particle Accelerator Conference (IPAC '10) (Internet), p.3927 - 3929, 2010/05

The ($underline{H}$)ybrid type thick ($underline{B}$)oron-doped ($underline{C}$)arbon (HBC) stripping foils are installed and used for the beam injection at the 3GeV RCS (Rapid Cycling Synchrotron) in J-PARC (Japan Proton Accelerator Research Complex). Up to now, the performance deterioration of the stripping foils can not be seen after the long beam irradiation for the 120kW user operation and 300kW high power beam demonstration at the RCS. In order to examine the characteristic of the HBC foils, various beam studies were carried out. The beam-irradiated spot at the foil was measured by scanning the foil setting position, the charge exchange efficiency was evaluated with various thickness foils, and the effect of the SiC fibers supporting the foil mounting was checked with different mounting foils. Beam study results obtained with using the HBC foils will be presented. In addition, the trends of outgas from the stripping foils and the deformations of the foils during the beam irradiation will be reported.

Journal Articles

Study of stellar reactions in explosive hydrogen burning with CRIB

Kubono, Shigeru*; Teranishi, Takashi*; Notani, Masahiro*; Yamaguchi, Hidetoshi*; Saito, Akito*; He, J. J.*; Wakabayashi, Yasuo*; Fujikawa, Hisashi*; Amadio, G.*; Baba, Hidetada*; et al.

Nuclear Physics A, 758, p.733 - 736, 2005/07

With using $$^{17}F$$ RNB from CRIB, proton inelastic scattering was observed. From this experiment, some resonance parameters have been deduced for the key reaction, $$^{14}O(alpha,p)^{17}F$$ at the explosive hydrogen burning stage in stars. Proton inelastic scattering of $$^{23}Mg$$ are also reported.

JAEA Reports

Analysis of Hydraulic and Transport Characteristics in Fracture of Micro Structure Using Cell Automata

Nishiyama, Satoshi*; Uehara, Shinichi*; Yano, Takao*; Saito, Ryuhei*; Uchida, Masahiro; Atsushi, Sawada,; Takebe, Atsuji

JNC-TY8400 2005-007, 70 Pages, 2005/03

JNC-TY8400-2005-007.pdf:2.24MB

None

JAEA Reports

Development of carbon/carbon composite control rod for HTTR, 2; Concept, specifications and mechanical test of materials

Eto, Motokuni; Ishiyama, Shintaro; Fukaya, Kiyoshi; Saito, Tamotsu; Ishihara, Masahiro; Hanawa, Satoshi

JAERI-Research 98-003, 34 Pages, 1998/01

JAERI-Research-98-003.pdf:1.26MB

no abstracts in English

Journal Articles

Nuclear applications of polycrystalline graphites to high temperature structural components

; Nishiyama, Yutaka; Ishihara, Masahiro

Proc. of the 2nd Japan Int. SAMPE Symp. on Advanced Materials for Future Industries,Needs and Seeds, p.1183 - 1190, 1991/00

no abstracts in English

Oral presentation

Technology development for decommissioning in FUGEN and current status

Kitamura, Koichi; Sano, Kazuya; Nakamura, Yasuyuki; Matsushima, Akira; Matsuo, Hidehiko; Ishiyama, Masahiro; Haneda, Takahiro; Tezuka, Masashi

no journal, , 

The decommissioning program of proto-type Advanced Thermal Reactor (ATR) FUGEN has started in 2008 as first decommissioning of the commercial-scale water reactor. It consists of four periods, considering the transportation of spent fuels and the radioactive decrease of highly activated materials. It is expected that the whole program of decommissioning will be completed until 2028.Now, the decommissioning is under the first period, spent fuels and heavy water has been carrying out from FUGEN, and a part of the turbine system with relatively low radioactive contamination has been dismantled. FUGEN has a complicated core structure consisting 224 fuel channels with pressure tubes and calandria tank, etc. and used heavy water as moderator, unlike other light water reactor. So, the dismantling technology of the reactor core and the decontamination technology of tritium in heavy water system, etc. have been studying in order to dismantle them safely. In this presentation, the contents of the decommissioning program and its current status, the studying situation of dismantling technology of reactor core using Abrasive Water Jet (AWJ) which is a candidate of cutting technologies, the examination of tritium decontamination in heavy water system, the study for C-14 penetrated into concrete structure will be presented mainly.

Oral presentation

Well-ordered arrangement of Ag nanoparticles in SiO$$_{2}$$/Si by ion implantation

Ninakuchi, Yuki*; Saito, Masahiro*; Isshiki, Toshiyuki*; Nishio, Koji*; Nishiyama, Fumitaka*; Yamamoto, Shunya; Sasase, Masato*; Takahiro, Katsumi*

no journal, , 

In the course of Ag implantation into thermally grown SiO$$_{2}$$ films, we found well-ordered Ag nanoparticles in the vicinity of SiO$$_{2}$$/Si interface. SiO$$_{2}$$ films of 300 nm thick were grown on single crystalline Si(111) substrates. The SiO$$_{2}$$/Si samples were implanted with 350 keV-Ag ions to a fluence of 1$$times$$10$$^{17}$$ ions/cm$$^{2}$$. The Ag-implanted SiO$$_{2}$$/Si samples were characterized by Rutherford backscattering spectrometry (RBS), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and cross sectional transmission electron microscopy (XTEM). The Ag concentration depth profiles obtained by RBS and XPS were non-Gaussian, indicating that Ag atoms diffused significantly. XTEM revealed that well-arranged Ag nanoparticles of 30 nm and 2 nm in diameter were distributed near the projected range and the SiO$$_{2}$$/Si interface, respectively.

Oral presentation

Tritium removal test for decommissioning of FUGEN

Matsushima, Akira; Ishiyama, Masahiro; Matsuo, Hidehiko; Sato, Yuji

no journal, , 

no abstracts in English

Oral presentation

Current status of the decommissioning of FUGEN

Ishiyama, Masahiro; Nakamura, Yasuyuki

no journal, , 

We'll attend the 53rd meeting of Technical Advisory Group in America and report the status of turbine facilities dismantlement and the R&D of laser cutting technology.

Oral presentation

Study on the method for cutting pipes in high radiation area for the isolation of reactor core from other systems in FUGEN

Takiya, Hiroaki; Matsushima, Akira; Ishiyama, Masahiro; Okuzawa, Kazuhiro

no journal, , 

no abstracts in English

Oral presentation

Specialized training on decommissioning

Isomi, Kazuhiko; Matsushima, Akira; Nakayama, Tamotsu; Ishiyama, Masahiro; Nakamura, Yasuyuki

no journal, , 

no abstracts in English

Oral presentation

In-situ measurement using of high resolution elastic wave velocity measurement system to understand a groundwater flow in rock mass

Matsui, Hiroya; Ishiyama, Koji*; Yoshino, Osamu*; Hikima, Ryoichi*; Sanoki, Satoru*; Hayashi, Kunihiko*; Takahashi, Masahiro*; Sato, Masaru*

no journal, , 

This paper is described about the results of collaboration study between Nishimatsu cop. and JAEA to estimate the applicability of high resolution elastic wave velocity measurement for understanding of a groundwater flow. The measurement was carried out in the vicinity of the groundwater recovery test drift in MIU and it continued for about three month from just after starting at the drainage of the test drift. The results suggested that the elastic wave velocity change were measured with groundwater flow due to drainage of the test drift and the high resolution elastic wave velocity measurement can be applicable for understanding of groundwater flow.

Oral presentation

Development of the electrolytic decontamination machine for pipes, 3; Relationship between electrolytic polishing depth and decontamination performance

Maruyama, Akira*; Sasaki, Katsuya*; Daiku, Hiroyuki*; Ishiyama, Masahiro; Yoshida, Yuto*; Aratani, Kenta

no journal, , 

no abstracts in English

Oral presentation

Dismantlement method in FUGEN

Aratani, Kenta; Ishiyama, Masahiro; Tezuka, Masashi

no journal, , 

no abstracts in English

Oral presentation

Dismantlement status and future plans in FUGEN

Aratani, Kenta; Ishiyama, Masahiro; Awatani, Yuto; Miyamoto, Yuta; Tezuka, Masashi

no journal, , 

no abstracts in English

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