Annual report for research on geosphere stability for long-term isolation of radioactive waste in fiscal year 2016

Ishimaru, Tsuneari; Yasue, Kenichi*; Asamori, Koichi; Kokubu, Yoko; Niwa, Masakazu; Watanabe, Takahiro; Yokoyama, Tatsunori; Fujita, Natsuko; Saiga, Atsushi; Shimizu, Mayuko; et al.

JAEA-Research 2018-008, 83 Pages, 2018/12

JAEA-Research-2018-008.pdf:11.43MB

This annual report documents the progress of research and development (R&D) in the 2nd fiscal year during the JAEA 3rd Mid- and Long-term Plan (fiscal years 2015-2021) to provide the scientific base for assessing geosphere stability for long-term isolation of the high-level radioactive waste. The planned framework is structured into the following categories: (1) Development and systematization of investigation techniques, (2) Development of models for long-term estimation and effective assessment, (3) Development of dating techniques. In this paper, the current status of R&D activities with previous scientific and technological progress is summarized.

Mechanical properties of full austenitic welding joint at cryogenic temperature for the ITER toroidal field coil structure

Iguchi, Masahide; Saito, Toru; Kawano, Katsumi; Chida, Yutaka; Nakajima, Hideo; Ogawa, Tsuyoshi*; Katayama, Yoshinori*; Ogata, Hiroshige*; Minemura, Toshiyuki*; Tokai, Daisuke*; et al.

Fusion Engineering and Design, 88(9-10), p.2520 - 2524, 2013/10

https://doi.org/10.1016/j.fusengdes.2013.02.165

ITER TFC structures are large welding structures made of heavy thick stainless steels. JAEA plans to apply narrow gap TIG welding with FMYJJ1 which is full austenitic stainless filler material to manufacture TFC structure. FMYJJ1 is specified in "Codes for Fusion Facilities -Rules on Superconducting Magnet Structure (2008)". In order to evaluate effect of base material combinations and thickness of welded joint on tensile properties at 4 K, tensile tests were conducted at 4 K by using tensile specimens taken from 40 mm thickness weld joints of four combinations and 200 mm thickness ones of two combinations of base materials. These weld joints were manufactured by one side narrow gap TIG welding with FMYJJ1. As the results, it was confirmed that yield and tensile strengths of welded joint at 4K were decreased with decreasing of nitrogen of base material, and there were no large distribution of strengths at 4 K along the thickness of welded joints of 200 mm thickness.

Development of structures for ITER toroidal field coil in Japan

Iguchi, Masahide; Chida, Yutaka; Takano, Katsutoshi; Kawano, Katsumi; Saito, Toru; Nakajima, Hideo; Koizumi, Norikiyo; Minemura, Toshiyuki*; Ogata, Hiroshige*; Ogawa, Tsuyoshi*; et al.

IEEE Transactions on Applied Superconductivity, 22(3), p.4203305_1 - 4203305_5, 2012/06

https://doi.org/10.1109/TASC.2011.2177795

Japan Atomic Energy Agency (JAEA) has responsibility to procure 19 structures for ITER toroidal field (TF) coils as in-kind components. JAEA plans to use materials specified in the material section of "Codes for Fusion Facilities; Rules on Superconducting Magnet Structure (2008)" issued by the Japan Society of Mechanical Engineers (JSME) in 2008. Large forged products were produced and their mechanical properties at 4K were evaluated. In addition, the following activities have been performed; (1) to optimize the design of each weld type identified in the manufacturing sequence, (2) to qualify typical welding procedure including repair, (3) to establish welding techniques other than narrow gap TIG welding with FMYJJ1, (4) to demonstrate the manufacturing procedures through manufacture of 1-m mockups and full-scale segments of TFC structure. This paper describes the results of material qualification and industrialization activities of manufacturing processes of ITER TFC structure.

Carbon kinetic analysis in a soybean plant by using newly developed real-time whole-plant imaging method with positron emitting tracer imaging system (PETIS)

Kawachi, Naoki; Suzui, Nobuo; Ishii, Satomi; Yamazaki, Haruaki; Iwasaki, Aya*; Ogawa, Kenichi*; Fujimaki, Shu

JAEA-Review 2011-043, JAEA Takasaki Annual Report 2010, P. 93, 2012/01

https://jopss.jaea.go.jp/pdfdata/JAEA-Review-2011-043.pdf

Carbon translocation in a whole plant body by using Positron Emitting Tracer Imaging System (PETIS) and carbon-11-labeled carbon dioxide (CO)

Kawachi, Naoki; Suzui, Nobuo; Ishii, Satomi; Ito, Sayuri; Ishioka, Noriko; Yamazaki, Haruaki; Iwasaki, Aya*; Ogawa, Kenichi*; Fujimaki, Shu

JAEA-Review 2010-065, JAEA Takasaki Annual Report 2009, P. 101, 2011/01

https://jopss.jaea.go.jp/pdfdata/JAEA-Review-2010-065.pdf

Development of laser decontamination technique (VII); The pollution distribution check examination of the test piece after laser decontamination

; Fukui, Yasutaka; ; Tanimoto, Kenichi

JNC TN9410 2001-028, 62 Pages, 2001/12

JNC-TN9410-2001-028.pdf:6.96MB

On irradiating laser ray to surface of metal, the surface is rapidly heated, melted, and evaporated. Laser decontamination technique has been developed by using the transpire process to radionuclides contaminated machine surface. The decontamination experiments using normal pulse YAG laser and hot sample were carried out. In the experiments, it was understood that even if the surface is ground by 150m or more, radioactivities could not be completely removed. 0n this account, for the purpose of study the depth where a radioactivities merges in the metal by the laser irradiation, surveys using the hot test specimen were per拓rmed. Results are as follows. (1) Observation of topographic profile suggested that the depth of irregularity by laser irradiation were from 200m to 500m, and there were crud on the surface, which seems reattached melting crud by laser irradiation. (2) Metallic composition analysis with fluorescent X-ray analysis device suggested that there was the segregation of Cr in the test specimen that used Air for the assistance gas, and there were not the segregation that used Ar for the assistance gas. (3) The radioactivity analysis of the test specimen that uses the imaging plate and the radio autograph could not clear the distribution of radioactivities. However, it could be confirmed that a radioactive nuclide exited in a range of 500 m or less. (4) Grounding the test specimen and measurement of the doses of radiation with Ge measuring tool suggested that there were radioactivities up to the depth of 300m in the test specimen which used Air for the assistance gas, and 120m in the test specimen which used Ar for the assistance gas.

Development of dismantling method for liquid waste tanks lined with rubber in "Joyo" waste treatment facility

; ; Kondo, Hitoshi; Tanimoto, Kenichi

JNC TN9410 2001-007, 105 Pages, 2000/12

JNC-TN9410-2001-007.pdf:7.42MB

Dismantling methods of liquid waste tanks lined with flammable natural rubber for decommissioning of Joyo Waste Treatment Facility. In this development, we researched common mechanical and heat cutting methods and chose appropriate one that was effective to decrease exposure and had no risk to fire the natural rubber lining. We next carried out dismantling tests using the chosen method with rubber lined mock-ups ofthe tanks to obtain cutting conditions and removal conditions of the lining to minimize secondary wastes. Results are follows. (1)We chose abrasive water jet that has an ablity to remove the rubber lining and to be controllable remotely with ease as a cutting method for the natural rubber lined tanks. (2)As a result of cutting tests under parameters of a cutting nozzle speed and a abrasive feed rate, cutting conditions minimizing secondary wastes are 0.4 kg/min abrasive feed rate and 300 mm/min nozzle speed. (3)As a result of a removing test under a parameter of a removing nozzle speed, a removing condition minimizing secondary wastes is 60 mm/min nozzle speed, thus removing speed is 3720 mm/min. (4)Improving the removing method, especially decreasing water feed, and general design of a dismantling system including treatment with secondly waste are required.

Development of the decommissioning management system (6); Evaluation of decommissioning method for JWTF old structure

; ; Tanimoto, Kenichi

JNC TN9410 99-022, 208 Pages, 1999/09

JNC-TN9410-99-022.pdf:8.62MB

An estimation for decommissioning of JWTF old structure using decommissioning management system was done to confirm "work term", "work qugntity", "exposure dose", "quantity of radioactive waste", and "cost". Two different decommissioning methods are used in the estimation work. The two methods are as follows. (a)Method A: Cutting work is done in the spot of equipments, waste occurred in the cutting work are stored in a waste container, and the waste is keep in a waste storage place. (b)Method B: In cutting work, equipments are dismantled to container size in the spot of decommissioning place, and also are dismantled in more small size in exclusive waste treatment facility, and are kept in the exclusive store place. The simulation named method B was ended before the waste was bought in the exclusive waste treatment facility, because we have not had the waste treatment facility. Those results are shown in the following. (1)Work term: 732days using the method A, and 517days using the method B. (2)Work quantity: 10,023 man*days using the method , and 6,931 man*days using the method B. (3)Exposure dose: 61,967 man*mSv using the method A, and 37,606 man*mSv using the method B. (4)Quantity of radioactive waste: 69,112kg using the method A, and 68,929kg using the method B. (5)Cost: 696,553 thousand yen using the method A, and 442,533 thousand yen using the method B.

Development of laser decontamination(5); Decontanination test of the hot samples

Fukui, Yasutaka; ; ; Tanimoto, Kenichi

JNC TN9410 99-016, 77 Pages, 1999/08

JNC-TN9410-99-016.pdf:2.82MB

Process of laser decontamination system is as follows. As the material is irradiated by laser beam, its surface is instantaneously heated and ablated. Laser decontamination system is able to decontaminate thoroughly. In this work, the characteristics of laser beam transmission by optical fibers, and decontamination effect of laser beam irradiation to test pieces which are cut down of pipe in the hot facility, are experimented for apply laser decontamination technique to radioactive wastes treatment and decommissioning of nuclear fuel facilities. The results are as follows. (1)Beam transmission. Transmission of Q switch pulse YAG laser's beam by optical fibers are examined. Transmission energy is in proportion to incident energy to fiber. Transmission energy of bundled fiber is 168mJ to 406mJ of incident energy. In the case of incident energy was 425mJ, transmission energy was decrease, because some fibers of bundled fiber were damaged by laser beam. (2)Decontamination test of the hot samples. Counting rate of pipe test piece were decreased more than 90% by first irradiation of Q switch pulse YAG laser. Counting rate of pipe test piece were decreased no more than 4% by on and after second irradiation of Q switch pulse YAG laser. To move the test piece slowly, and to raise the density of irradiation energy, and to use the helium gas for auxiliary gas are effective to increase decontamination effect.

Development of laser decontamination technique(3); Experiments of laser beam transmission

Fukui, Yasutaka; ; ; Tanimoto, Kenichi

JNC TN9410 99-008, 157 Pages, 1999/04

JNC-TN9410-99-008.pdf:4.32MB

Laser decontamination system is able to decontaminate thoroughly, and it is able to mitigate the secondary waste quantity, and the system is able to operate by remote control. It is advantageously method compared with other decontamination methods. Irradiation by YAG laser beam is competent for decontamination of stainless steel surface. In this paper, using normal and Q switch pulse YAG laser, Experiments to confirm transmission efficiency using mirror and optical fiber, shape dependency at decontamination, and secondary waste size distribution were performed. The results of the work are as follows. (1) The beam energy of normal pulse YAG laser is able to transmit using optical fiber. The beam energy of Q switch pulse YAG laser is difficult to transmit using a single optical fiber. (2) Normal pulse YAG laser has 10 Decontamination Factor (DF) on L-shaped, bolt-shaped, and cylindrical-shaped waste. Q switch pulse YAG laser has over 10 DF on L-shaped and cylindrical-shaped waste, but on the other hand, under 10 DF on bolt-shaped waste. (3) In the case of using the argon gas as auxiliary gas, almost particles of secondary products are dropped as dross. In the case, scattering area is within 1m. On the other hand, in the case of using the atmosphere gas as auxiliary gas, almost particles of secondary products are floated in the air, its diameter are under 3m.