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Ito, Kimio; Soma, Susumu; Ono, Takayuki; Ishimori, Yuu; Kawasaki, Satoru
JAEA-Review 2011-011, 20 Pages, 2011/03
JAEA-Review-2011-011.pdf:1.59MB
The Ningyo-toge Environmental Engineering Center of the Japan Atomic Energy Agency performs the environmental monitoring around the Ningyo-toge and the waste rock sites according to the agreements with local governments, Okayama and Tottori prefectures. Each prefectural committee on the environmental monitoring evaluates the monitoring data annually. This report summarized the results of the environmental monitoring in Tottori prefecture in the fiscal year 2009. The results show that the levels of the radiation doses and the radioactive concentrations in the environment were within natural variations, and the waste rock sites have been well maintained. The committee concluded that the environmental impacts from the sites were negligible.
Ito, Kimio; Soma, Susumu; Ono, Takayuki; Ishimori, Yuu; Kawasaki, Satoru
JAEA-Review 2011-010, 44 Pages, 2011/03
JAEA-Review-2011-010.pdf:2.5MB
The Ningyo-toge Environmental Engineering Center of the Japan Atomic Energy Agency (JAEA Ningyo-toge) performs the environmental monitoring around the Ningyo-toge and the waste rock sites according to the agreements with local governments, Okayama and Tottori prefectures. Environmental monitoring of plutonium has been also performed around the Ningyo-toge regarding the practical application study on the reprocessed uranium conversion, which was carried out from 1994 to 1999 at the Ningyo-toge. Each prefectural committee on the environmental monitoring evaluates the monitoring data annually. This report summarized the results of the environmental monitoring in Okayama prefecture in the fiscal year 2009. The results show that the levels of the radiation doses and the radioactive concentrations in the environment were within natural variations, and the committee concluded that the environmental impacts from the sites were negligible. Therefore, the site of the JAEA Ningyo-toge has been well operated, and the waste rock sites have been well maintained.
Soma, Susumu; Ono, Takayuki; Ishimori, Yuu; Kawasaki, Satoru
JAEA-Review 2009-070, 43 Pages, 2010/03
JAEA-Review-2009-070.pdf:6.63MB
The Ningyo-toge Environmental Engineering Center of the Japan Atomic Energy Agency (JAEA Ningyo-toge) performs the environmental monitoring around the Ningyo-toge and the waste rock sites according to the agreements with local governments, Okayama and Tottori prefectures. Environmental monitoring of plutonium has been also performed around the Ningyo-toge regarding the practical application study on the reprocessed uranium conversion, which was carried out from 1994 to 1999 at the Ningyo-toge. Each prefectural committee on the environmental monitoring evaluates the monitoring data annually. This report summarized the results of the environmental monitoring in Okayama prefecture in the fiscal year 2008. The results show that the levels of the radiation doses and the radioactive concentrations in the environment were within natural variations, and the committee concluded the environmental impacts from the sites were negligible. Therefore, the site of the JAEA Ningyo-toge has been well operated, and the waste rock sites have been well maintained.
Soma, Susumu; Tago, Itaru; Ono, Takayuki; Ishimori, Yuu; Kawasaki, Satoru
JAEA-Review 2009-069, 43 Pages, 2010/03
JAEA-Review-2009-069.pdf:7.21MB
The Ningyo-toge Environmental Engineering Center of the Japan Atomic Energy Agency (JAEA Ningyo-Toge) performs the environmental monitoring around the Ningyo-toge and the waste rock sites according to the agreements with local governments, Okayama and Tottori prefectures. Environmental monitoring of plutonium has been also performed around the Ningyo-toge regarding the practical application study on the reprocessed uranium conversion, which was carried out from 1994 to 1999 at the Ningyo-toge. Each prefectural committee on the environmental monitoring evaluates the monitoring data annually. This report summarized the results of the environmental monitoring in Okayama prefecture in the fiscal year 2007. The results show that the levels of the radiation and the radioactive concentrations in the environment were within natural variations, and the committee concluded the environmental impacts from the sites were negligible. Therefore, the site of the JAEA Ningyo-Toge has been well operated, and the waste rock sites have been well maintained.
Soma, Susumu; Ono, Takayuki; Ishimori, Yuu; Kawasaki, Satoru
JAEA-Review 2009-068, 20 Pages, 2010/03
JAEA-Review-2009-068.pdf:4.54MB
The Ningyo-toge Environmental Engineering Center of the Japan Atomic Energy Agency performs the environmental monitoring around the Ningyo-toge and the waste rock sites according to the agreements with local governments, Okayama and Tottori prefectures. Each prefectural committee on the environmental monitoring evaluates the monitoring data annually. This report summarized the results of the environmental monitoring in Tottori prefecture in the fiscal year 2008. The results show that the levels of the radiation doses and the radioactive concentrations in the environment were within natural variations, and the waste rock sites have been well maintained. The committee concluded the environmental impacts from the sites were negligible.
Soma, Susumu; Tago, Itaru; Ono, Takayuki; Ishimori, Yuu; Kawasaki, Satoru
JAEA-Review 2009-067, 20 Pages, 2010/03
JAEA-Review-2009-067.pdf:4.54MB
The Ningyo-toge Environmental Engineering Center of the Japan Atomic Energy Agency performs the environmental monitoring around the Ningyo-toge and the waste rock sites according to the agreements with local governments, Okayama and Tottori prefectures. Each prefectural committee on the environmental monitoring evaluates the monitoring data annually. This report summarized the results of the environmental monitoring in Tottori prefecture in the fiscal year 2007. The results show that the levels of the radiation doses and the radioactive concentrations in the environment were within natural variations, and the waste rock sites have been well maintained. The committee concluded the environmental impacts from the sites were negligible.
Sakai, Kenji; Oi, Motoki; Kai, Tetsuya; Kinoshita, Hidetaka; Kawasaki, Susumu; Watanabe, Akihiko; Kaminaga, Masanori; Futakawa, Masatoshi
Nuclear Instruments and Methods in Physics Research A, 600(1), p.75 - 77, 2009/02
Times Cited Count：1 Percentile：12.35(Instruments & Instrumentation)In order to operate all equipment of the Materials and Life Science Experimental Facility (MLF) safely and efficiently, the MLF general control system (MLF-GCS) is designed to have several subsystems such as the facility control system centering on the control of the targets, interlock systems for protecting personnel, machine and the neutron target, and so on. Although it is an independent system, the MLF-GCS should also be as a part of the control system of the whole J-PARC operated from the central control room (CCR). The construction of MLF-GCS has been almost finished, and its performance test is in progress to check and adjust remote operations and integral interlocks from the control room of MLF. This paper gives an overview of the MLF-GCS and reports its construction status.
Kawasaki, Manabu*; Taniguchi, Naoki; Kawakami, Susumu
JNC TN8400 2004-028, 37 Pages, 2005/03
JNC-TN8400-2004-028.pdf:41.12MB
In geological disposal of high-level radioactive waste in soft rock, the cement material will be used as concrete support to ensure the mechanical stability of underground tunnel. The pH in ground water becomes high by the contact with cement. Therefore, the influence of cement on the corrosion of copper which is one of the candidate materials for overpacks was investigated. The anodic polarization measurement and immersion test in reducing environment were carried out, using the solution simulating the seawater(SSW) in contact with ordinary portland cement(OPC) and low alkaline cement (HFSC). The anodic polarization curves on SSW and SSW + HFSC were active dissolution type and, the polarization curve of SSW + OPC, was active dissolution / passivation transition type. The polarization curves in bentonite were active dissolution type. These results were consistent with results that have already reported. As the results of immersion test, corrosion rates became small with time. The growth of corrosion for 90day and one year immersion test was small and the average corrosion depth was in the order 0.1um. Within the test conditions, the influence of cement materials on the corrosion of was not significant.
Kawasaki, Manabu*; Taniguchi, Naoki; Kawakami, Susumu
JNC TN8400 2004-027, 94 Pages, 2005/03
JNC-TN8400-2004-027.pdf:59.54MB
The immersion tests of pure copper which is one of the candidate overpack materials were carried out in synthetic sea water (SSW) and in bentonite under low oxygen atmosphere at 80 degrees Celsius with changing the sulfide concentration. As the results, corrosion rates became large with increase in sulfide concentration both in simple solution and in bentonite. The corrosion rates tended to be lowered with time in every cases. Assuming that the corrosion is controlled by diffusion of HS- in bentonite, the corrosion rates were calculated for experimental conditions of bentonite thickness and compared with the values obtained in the experiments. The calculated corrosion depths were larger than experimental results. And then assuming the actual thickness of the buffer material, the long-term corrosion depth was estimated based on the diffusion of HS- in bentonite. As the results, the corrosion depth in 1000 years was 0.5mm (HS- 0.001M), 1.76mm (HS- 0.005M), 14mm (HS- 0.1M). It is likely that the corrosion product film formed in solution was tightly adhere to surface and seemed to protective. On the other hand, only a thin film was observed in bentonite at low sulfide concentration condition, and the corrosion product film formed in high sulfide concentration condition was easily broken away from the surface. It is considered that corrosion product formed in bentonite was less protective. According to the X-ray diffraction measurement, Cu2O (cuprite) was detected in SSW without sulfide, and Cu2S (chalcocite) was detected in the presence of sulfide.
Taniguchi, Naoki; Kawasaki, Manabu*; Kawakami, Susumu; Kubota, Mitsuru*
JNC TN8400 2003-040, 142 Pages, 2004/03
JNC-TN8400-2003-040.pdf:11.15MB
The deep underground environment for geological disposal of HLW will be relativery oxidizing condition at the initial stage of repository, but it will be returned to reducing as the consumption of oxygen by the corrosion of overpack and the reactions with the minerals in buffer material. It is necessarly to understand the corrosion behaviour of carbon steel under such reducing condition for the lifetime prediction of carbon steel overpack. In this study, immersion tests of carbon steel in buffer material were performed in nitrogen atmosphere in which oxygen gas concentration was controlled less than 1 ppm. The corrosion rates of carbon steel were measured by weight loss of the specimens and the corrosion products were analysed by SEM, XRD and EPMA. For investigating the influence of welding of overpack, welded samples by electron-beam welding (EBW) were used for some of the tests. Synthetic sea water (SSW) and aqueous solutions containing bicarbonate ion and chloride ion were chosen as simulated groundwater. According to the experimental results, corrosion products layer contained ferrous carbonate such as FeCO3 and Fe2(OH)2CO3. The average corrosion rates within 1 year were relatively high (0.004-0.018mm/y), but the growths of corrosion after 1 year were decreased rapidly. The increase in average corrosion depths from 1 to 3 (or 4) years was only less than several micro-meters, and the realistic corrosion rates after 1 year were estimated to be less than 0.001m/y in many cases. There was no influence of welding on the corrosion rate of carbon steel up to 3 years of immersion period. The effects of the density of buffer material and the mixing ratio of sand in buffer material on the corrosion rate of carbon steel were also investigated in this study.
Kawasaki, Manabu*; Taniguchi, Naoki; Kawakami, Susumu
JNC TN8400 2003-041, 48 Pages, 2004/02
JNC-TN8400-2003-041.pdf:0.62MB
Copper is one of the candidate materials for overpacks and it is important to understand the corrosion behavior under oxidizing condition at the initial stage of repository. For understanding the influence of environmental factor on the corrosion rate of copper and corrosion localization, immersion tests of pure copper in aqueous solution and in bentonite were carried out under aerated condition in simulated groundwater environment.As the result, corrosion rate increased with increase in chloride ion concentration and fluoride ion concentration. The addition of bicarbonate ion reduced the corrosion rate of pure copper in the presence of chloride ion. The corrosion rates in bentonite were smaller than those in aqueous solution without bentonite, and decreased with increase in solid- (bentonite)/liquid(solution) ratio. For corrosion localization, the relationship between average corrosion depth and pitting factor was investigated. Although the magnitude of pitting factor depended on the experimental condition, it was tend to decrease with increase in average corrosion depth in all test cases. No data on pitting factor was over the upper limit level observed in natural soils. It was indicated that the maximum corrosion depth due to oxygen can be evaluated conservatively by estimating the upper limit of pitting factor from average corrosion depth.
Taniguchi, Naoki; Kawasaki, Manabu*; Kawakami, Susumu; Kubota, Mitsuru*
Proceedings of European Corrosion Congress 2004 (EUROCORR 2004), 0 Pages, 2004/00
Long-term immersion tests of carbon steel under anaerobic condition were conducted in bentonite environment. Based on the experimental results, corrosion rate and corrosion products were evaluated.
Taniguchi, Naoki; Kawasaki, Manabu*; Kawakami, Susumu; Suzuki, Haruo*
JNC TN8400 2003-016, 89 Pages, 2003/03
JNC-TN8400-2003-016.pdf:1.29MB
In current repository concept of high-level radioactive disposal in soft rock system, concrete support will be emplaced around the buffer material, and groundwater pH will be increased by the contact with cement. In such condition, carbon steel overpack i
Taniguchi, Naoki; Kawasaki, Manabu*; Kawakami, Susumu; Suzuki, Haruo*
13th Asian Pacific Corrosion Control Conference (APCCC-13) (CD-ROM), H06, 8 Pages, 2003/00
None
Kawasaki, Manabu*; Taniguchi, Naoki; Kawakami, Susumu
JNC TN8400 2002-016, 48 Pages, 2002/06
JNC-TN8400-2002-016.pdf:1.19MB
Copper is one of the candidate materials for overpacks. Anodic polarization curves of pure copper were measured at 80
C in carbonate solution and in bentonite/sand mixture in order to understand the corrosion behavior of copper overpack at oxidizing period. The experimental results in carbonate solutions indicated that the anodic polarization curves became active dissolution type with increase in chloride ion concentration, while anodic polarization curves became passive type with increase in bicarbonate ion concentration. No effect of sulfate ion concentration was observed on the type of anodic polarization curve. The passive film break down potential became less noble with increase in chloride ion concentration and sulfate ion concentration. In contrast, the passive film break down potential became noble with increase in bicarbonate ion concentration. By the comparison of these experimental results with previous study performed at 30 C, it was indicated that anodic polarization curves become passive type with the rise of temperature. However, no effect of temperature on passive film break down potential was observed within the experimental conditions. As to the results in bentonite/sand mixture, the effect of the composition in test solutions on the anodic polarization curves were small and the anodic polarization curves were almost active dissolution types.
*; Taniguchi, Naoki; Kawasaki, Manabu*; Kawakami, Susumu
JNC TN8400 2002-010, 45 Pages, 2002/04
JNC-TN8400-2002-010.pdf:12.36MB
In the 2nd progress report, the analysis of the creep rapture of buffer material by the expansion of the overpack corrosion product was carried out. In the analysis, the expansion ratio of corrosion products was assumed three times the initial volume of the steel, also the elasticity was equal to the material of the overpack for conservative evaluation. For more realistic evaluation, these parameters must be understood more correctly, but there are few results of other researches because of it was very difficult to get elasticity by the ordinary method from very few corrosion products through the corrosion test. In this study, we have try to get elasticity directly from corrosion products by the Nano-Indentation Method As a result, the elasticity were 50
70% of the bulk metal. The elasticity of the bulk metal were measured about 200GPa, ordinary value of carbon steel, it seems reasonable to apply this measuring method. About corrosion expansion, we have made test piece by the corrosion acceleration to have much more product in the short period, However, from EPMA and X-ray analysis of the products, it appeared that the acceleration of the test piece was not adequate for the simulation of expansion ratio. It is insufficient to argue the elasticity and corrosion expansion only from tentative results of this study, we must have much more results through the evaluation of corrosion acceleration method and relation of macroscopic characteristics of corrosion products and microscopic data, and so on.
*; Nakajima, Hideo; Kawasaki, T.*; *; Tsuji, Hiroshi; F.Wong*; Shimamoto, Susumu*
Proc. of 15th Int. Conf. on Magnet Technology (MT-15), p.989 - 992, 1997/10
no abstracts in English
Kinoshita, Hidetaka; Aizawa, Hideyuki; Kawasaki, Susumu; Ueda, Kazuaki; Takagiwa, Katsunori; Ito, Manabu; Kaminaga, Masanori; Kato, Takashi
no journal, ,
Construction of J-PARC pulsed spallation neutron source was completed. Main components of the spallation neutron source, as the mercury target container, reflector, moderators, proton beam window and etc, are damaged by irradiation of proton and/or neutron. Therefore, each component has to be replaced periodically. All these components must be replaced by remote handling, because of the high activation by proton beam and neutron irradiation. Remote handling facility for the neutron source components consists of handling device for the targetas the power manipulator, the target replacement truck for the target container replacement and other facilities for maintenance or replacement work, and the storage facility for cool down of the radioactivity in spent components including some kinds of rack for temporary storage and the cutting device for reducing volume. In this presentaion, it is repoted that the design and testresult of remote handling facility.
Takahashi, Yoshikazu; Nabara, Yoshihiro; Nunoya, Yoshihiko; Suwa, Tomone; Tsutsumi, Fumiaki; Oshikiri, Masayuki; Ozeki, Hidemasa; Shibutani, Kazuyuki*; Kawano, Katsumi; Kawasaki, Tsutomu*; et al.
no journal, ,
Japan Atomic Energy Agency (JAEA) is procuring all amounts of Nb
Sn conductors for Central Solenoid (CS) in the ITER project. Before start of mass-productions, the conductor should be tested to confirm superconducting performance in the SULTAN facility, Switzerland. The cable with a shorter twist pitch shows no degradation of Tcs against to electromagnetic load cycles. However, it is difficult to make the cable, because the diameter of the cable with shorter twist pitch is larger and the cable has to compact more. The technology for the cables with STP was developed in Japanese cabling suppliers. The several key technologies and production will be described in this paper.
