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Ono, Ayato; Takayanagi, Tomohiro; Sugita, Moe; Ueno, Tomoaki*; Horino, Koki*; Yamamoto, Kazami; Kinsho, Michikazu
JAEA-Technology 2021-044, 53 Pages, 2022/03
JAEA-Technology-2021-044.pdf:43.7MB
The 3-GeV rapid cycling synchrotron of Japan Proton Accelerator Research Complex (J-PARC) uses a large number of electromagnet power supplies in order to manipulate a high-intensity beam of 1 MW. These devices have been specially developed to meet the requirement to achieve acceleration of the 1-MW proton beams. Because J-PARC has been in operation for 10 years, we have to replace many parts and equipments due to failures caused by age-related deterioration. J-PARC accelerator system supplies the beams for many users, and we have to recover it as soon as possible when a trouble occurs. Therefore, if the trouble can be prevented before it happens, reduction of the user beam time can be minimized. Furthermore, it enables us to reduce additional work for operators. Maintenance is important to keep the equipments in a normal state, and makes it possible to extend the life of the equipments by detecting and maintaining the faulty parts and the aged deterioration parts at an early stage. Since all the devices requires the maintenance, there are a wide variety of maintenance methods. Some works are carried out by the J-PARC members, and some are performed by outsourcing. Ensuring safety and protecting workers are the most important issues in maintenance work. Therefore, J-PARC has rules for safety work. All workers in J-PARC have to learn and follow the rules. In addition, various ideas are being considered to enable safe and efficient work by devising ingenuity in each work. We also elaborate various ideas and processes for safe and efficient work according to the individual work conditions. In this report, we summarize the guideline and cautionary points during maintenance based on the actual case of maintenance and inspection work of the horizontal shift bump electromagnet power supply.
Hirose, Takanori; Shiba, Kiyoyuki; Sawai, Tomotsugu; Jitsukawa, Shiro; Akiba, Masato
Journal of Nuclear Materials, 329-333(Part1), p.324 - 327, 2004/08
Times Cited Count：55 Percentile：94.79(Materials Science, Multidisciplinary)Reduced activation ferritic/martensitic steel, RAFs is the leading candidates for the structural materials of breeding blankets. HIP is examined as a near-net-shape fabrication process for this structure. The HIP requires heating above the normalizing temperature and the final microstructural features depends on the HIP processing conditions. Conventional HIP process caused a prior-austenite grain (PAG) coarsening of RAFs and subsequent increase of ductile brittle transition temperature. Japanese RAFs F82H and its modified steels were investigated by metallurgical method after isochronal heat treatment up to 1473K simulating HIP equivalent thermal hysteresis. Although Conventional F82H IEA heat showed significant grain growth after conventional solid HIP conditions (1313K 
2hr.), F82H with 0.1wt.% tantalum kept fine grain after the same heat treatment. On the other hands, conventional RAF/Ms with coarse grain were recovered by the post HIP normalizing at temperature below TaC dissolution temperature. This process can refine the PAG size of F82H more than ASTM grain size number 7.
Aihara, Jun; Ishihara, Masahiro; Hojo, Kiichi; Furuno, Shigemi*
Journal of the American Ceramic Society, 87(6), p.1146 - 1148, 2004/06
Times Cited Count：1 Percentile：18.37(Materials Science, Ceramics)SiC specimens were amorphized with Ne irradiation and annealed at 1273K. One specimen was annealed continuously for 60 minutes, the other was annealed repeatedly (5 minutes 10 times). Crystal nucleation in the amorphized SiC was apt to occur more in the case of repeated annealing than in the case of continuous annealing.
Nomura, Yasushi*; Okuno, Hiroshi; Miyoshi, Yoshinori
JAERI-Tech 2004-030, 64 Pages, 2004/03
JAERI-Tech-2004-030.pdf:4.59MB
no abstracts in English
-ray monitorTonoike, Kotaro; Nakamura, Takemi*; Yamane, Yuichi; Miyoshi, Yoshinori
Nuclear Technology, 143(3), p.364 - 372, 2003/09
Times Cited Count：2 Percentile：18.9(Nuclear Science & Technology)no abstracts in English
-ray and thermal neutron detectorsYanagisawa, Hiroshi; Ono, Akio
Journal of Nuclear Science and Technology, 39(6), p.597 - 602, 2002/06
Times Cited Count：2 Percentile：16.96(Nuclear Science & Technology)no abstracts in English
Nakahara, Yoshinori; Suyama, Kenya; Inagawa, Jun; Nagaishi, Ryuji; Kurosawa, Setsumi; Kono, Nobuaki; Onuki, Mamoru; Mochizuki, Hiroki*
Nuclear Technology, 137(2), p.1 - 16, 2002/02
no abstracts in English
; Kondo, Toshiyuki; *
JNC TN8440 2001-024, 210 Pages, 2001/08
JNC-TN8440-2001-024.pdf:24.99MB
In order to make this book reflect in the investigation which turned the bitumen solidification object to maintenance of the abandonment object technical standard on condition of carrying out subterranean disposal in the future - solidification - it created for the purpose of utilizing as precious sources of information, such as a nuclide inventory in the living body, group-izing of the past campaign required for typical solidification object selection, and information offer at the time of disposal examination. A development operation history collected so that histories including the shift action in an institution of the formation of discharge reduction of the characteristic of solidification object manufacture outlines, such as composition of the process of an institution and a solidification object and a storage actual result, the contents of an examination of the past campaign, and the solidification object manufactured based on topics or radioactive iodine and radioactive carbon etc., such as the past contents of an examination / operation, may grasp comprehensively in creation, and it carried out as the composition stared the trend of future disposal fixedly. It was a period (for 16 years) until an bituminization demonstration facility processing institution will start a cold examination from April (Showa 57), 1982, and it starts a hot examination from May 4, it starts solidification processing technical development operation from october 6 and it results in the fire explosion accident on March 11 (Heisei 9), 1997, and low level radioactivity concentration waste fluid was processed 7,438 m
, and 29,967 bitumen solidification objects were manufactured. According to the accident, it is necessary to hand it down to future generations with processing technology while the bitumen solidification object manufactured in 15 years although the bituminization demonstration facility processing institution came to close the mission holds information precious ...
Futakuchi, Katsuhito*; Hashimoto, Shuji*; Sakuramoto, Yuji*; ;
JNC TN8400 2001-007, 52 Pages, 2001/04
JNC-TN8400-2001-007.pdf:2.34MB
As a natural analogue, the authors investigted a Tertiary argillaceous bed and a Quarternary hypabyssal rock (porphyrite) which intruded into the argillaceous rock, distributed in the Nishikubiki district of Niigata prefecture in Japan. We examined the variation of clay mineral species in the argillaceous rock surrounding the intrusive rock and carried out thermal analyses for the argillaceous rock based on the coolig history of the intrusive rock. The predominant clay mineral varied from montmorillonite to illite through illite/montmorillonite interlayers with approaching to the intrusive rock. The thermal analyses indicated that the temperature descended from 270 to 15 
C during the 7.5 10
years at alocalty of argillaceous rock containing 75% illite in the interlayers. On the assumption that the alteration from montmorillonite to illite was regarded as a first-order reaction, we evaluated the apparent activation energy based on the thermal condition mentioned above; about 103 kJ/mol was obtained for this illitization. This was within the range of values reported previously by laboratory experiments and/or examinations of natural illitizations.
; ; Ueno, Fumiyoshi; ; ; ;
JNC TN2400 2000-005, 103 Pages, 2000/12
JNC-TN2400-2000-005.pdf:3.98MB
Inelastic analyses of the floor liner subjected to thermal loading due to sodium leakage and combustion were carried out, considering thinning of the liner plate due to molten salt type corrosion. Because the inelastic strain obtained by the analyses stayed below the ductility limit of the material, mechanical integrity, i.e., there exist no through-wall crack on the floor liner, was confirmed. Partial structural model tests were conducted, with a band of local thinning of the liner plate. Displacements were controlled to give specimens much larger strains than those obtained by the inelastic analyses above. No through-wall crack was observed by these tests. Mechanical integrity of the floor liner was confirmed by these results of the inelastic analyses and the partial structural model tests.
*
JNC TN1400 2000-007, 100 Pages, 2000/07
JNC-TN1400-2000-007.pdf:4.67MB
no abstracts in English
; Koyama, Tomozo; Funasaka, Hideyuki
JNC TN8400 2000-014, 78 Pages, 2000/03
JNC-TN8400-2000-014.pdf:2.13MB
We investigated the factors which affected the dissolution of U and Pu to the nitric acid solution with the fragmentation model, which was based on the results of dissolution experiments for the irradiated fast reactor fuels in the Chemical Processing Facility(CPF). The equation that gave the fuel dissolution rate was estimated with the condition of fabrication (Pu ratio (Pu/(U+Pu))), irradiation (burn-up) and dissolution (nitric acid concentration, solution temperature and U+Pu concentration) by evaluating these effects quantitatively. We also investigated the effects of fuel volume ratio to the solution in the dissolver, burn-up and flouring ratio of the fuel on the f-value (the parameter which shows the diffusion and osmosis of nitric acid to the fuel) in the fragmentation model. It was confirmed that the fuel dissolution rate calculated with this equation had better agreement with the results of dissolution experiments for the irradiated fast reactor fuels in the CPF than that estimated with the surface area model. In addition, the efficiency of this equation was recognized for the dissolution of unirradiated U pellet and high Pu enriched MOX fuel. It was shown that the dissolution rate of the fuel slowed down at the condition of the high U-Pu concentration dissolution by the calculation of the dissolution behavior with this equation. The dissolution of the fuel can be improved by increasing the nitric acid concentration and temperature, but from the viewpoint of lowering the corrosion of the dissolver materials, it is desirable that the f-value is increased by optimizing the condition of shearing and stirring for the improvement of dissolution.
Uwaba, Tomoyuki; ;
JNC TN9400 2000-006, 50 Pages, 1999/11
JNC-TN9400-2000-006.pdf:2.17MB
In the fast reactor the swelling of the fuel cladding occur due to the irradiation. Under the irradiation, the temperature gradient of the cladding through the direction of its thickness causes the swelling gradient and this will cause the secondary stress. In this study, we analyzed this secondary stress using the finite element model of the irradiation induced deformation of the cladding by FINAS code. The result of this analysis is summarized as follows. (1)The secondary stress is mainly caused by the gradient of the incubation period of the swelling, The secondary stress becomes very small at the end of irradiation due to the relieving of the stress by the irradiation creep deformation accelerated by the swelling. (2)The calculated maximum stress including the secondary stress under the irradiation is compared with the design value of the ultimate tensile strength for PNC316 for trial. The calculated value are lower than the design value. (3)The effect of the swelling accelerated by the stress is analyzed using the correlation between the swelling and the stress. The result shows that the increasing of the secondary stress due to the acceleration of the swelling is very small because the irradiation creep deformation relieves the stress more effectively by the acceleration of the irradiation creep rate due to the swelling.
-ray analysis of Gulf marine environmental samplesYonezawa, Chushiro; Matsue, Hideaki; Adachi, Takeo; Hoshi, Michio; Tachikawa, Enzo*; Povinec, P. P.*; S.W.Fowler*; M.S.Baxter*
IAEA-TECDOC-1094, p.344 - 345, 1999/07
no abstracts in English
Shiotsu, Masahiro*; Hata, Koichi*; *; Shirai, Yasuyuki*; *; Sakai, Takaaki
PNC TY9604 97-002, 15 Pages, 1997/03
no abstracts in English
; Nakano, Yoshihiro; Yamane, Yoshihiro*; *;
JAERI-Research 95-059, 83 Pages, 1995/09
JAERI-Research-95-059.pdf:2.24MB
no abstracts in English
*; *; Tachikawa, T.*; Agematsu, Takashi; Okumura, Susumu; Arakawa, Kazuo
Proceedings of 13th International Conference on Cyclotrons and Their Applications, p.644 - 647, 1993/00
no abstracts in English
Kamei, Gento; Yusa, Yasuhisa; Sasaki, Noriaki
PNC TN8410 91-253, 8 Pages, 1992/01
Time-temperature conditions and water chemistry on illitization at the Murakami deposit in central Japan were determined. The extent of the illitization and time-temperature condition estimated were as follows: the duration for conversion from 0 to 80% illite (volumetric ratio) was approximately 3.5 Ma in the temperature range from 340 to 100C, Conversion from 0 to 40% requires approximately 3.0 Ma in the temperature range from 240 to 100C, During 2.0Ma in the temperature range from 160 to 100C, however, illite was scaroely observed, Water chemistry is estimated from two approaches, namely laboratory experiment and numerical analysis. The former is an interactive experiment between seawater and the tuff of the deposit. The latter is a calculation based on the difference of bulk composition between illitized and non-illitized tuff. The extent of each ionic concentration is inferred to be as follows: K
; 560 to 6400, Mg
; 800 to 1700, Ca; 360 to 2900, Na; 9400 to 15000 (mg/l).
