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Yamada, Fumiaki; Kitamura, Kenji*
Proceedings of 12th International Conference on Nuclear Engineering (ICONE-12) (CD-ROM), 0 Pages, 2004/04
None
Fukano, Yoshitaka; Charpenel, J.*
Proceedings of 12th International Conference on Nuclear Engineering (ICONE-12) (CD-ROM), 8 Pages, 2004/04
Focusing on the cover layer materials (as the Radon Barrier Materials), which could have the effect to restrain the radon from scattering into the air and the effect of the radiation shielding, we produced the radon barrier materials with crude bentonite on an experimental basis, using the rotary type comprehensive unit for grinding and mixing, through which we carried out the evaluation of the characteristics thereof.
Kamide, Hideki; Miyakoshi, Hiroyuki; Kawamata, Nobuhiro; Ohshima, Hiroyuki
Proceedings of 12th International Conference on Nuclear Engineering (ICONE-12) (CD-ROM), 49199 Pages, 2004/04
High burnup core is one of significant ways to increase cost performance of a fuel cycle. Deformation of a pin bundle or wrapper tube due to irradiation has been studied for the high burnup core. Here, mixing phenomena with cross flow was investigated for a prediction method of thermohydraulics in a deformed pin bundle in a fast reactor. Sodium experiments were carried out using a wire wrapped 37-pin subassembly model, where a blockage was installed in order to make cross flow around it. The subchannel analysis code, ASFRE, was applied to the experimental analyses. Axial and transverse temperature distributions in the subassembly were correlated with the cross flow and the wire spacer. The calculated temperature profiles including a decrease due to the cross flow were in good agreement with the experimental results. ASFRE simulated also influence of the wire spacer. Database for mixing phenomena with the cross flow was obtained for a subassembly of fast reactor
Chikazawa, Yoshitaka; Hori, Toru; Konomura, Mamoru; Sato, Hiroyuki*; Uchida, Shoji*
Proceedings of 12th International Conference on Nuclear Engineering (ICONE-12) (CD-ROM), 49076 Pages, 2004/04
Focusing on the cover layer materials (as the Radon Barrier Materials), which could have the effect to restrain the radon from scattering into the air and the effect of the radiation shielding, we produced the radon barrier materials with crude bentonite on an experimental basis, using the rotary type comprehensive unit for grinding and mixing, through which we carried out the evaluation of the characteristics thereof.
Aoyama, Takafumi; Robert, W. S.; Maeda, Shigetaka; Sekine, Takashi
12th International Conference on Nuclear Engineeri, 0 Pages, 2004/00
Many changes were made in the recent upgrade of the JOYO experimental fast reactor to the MK-III design. Among the core changes made to achieve a four fold increase in irradiation capacity are the introduction of a second enrichment zone, an increase in core radius and a smaller decrease in core height. Performance tests done at low power, which focus on the neutronics characteristics, are presented. These tests include nuclear instrumentation system response, the approach to critical and excess reactivity, control rod calibrations performed several ways, and isothermal temperature coefficient evaluation. The measurements are emphasized but comparisons with calculated predictions are included. The design predictions are consistent with the performance test results, and all technical safety specifications are satisfied. The JOYO MK-III core will provide enhanced irradiation testing capability, as well as serving as a test bed for improving fast reactor operations, performance and
Haga, Katsuhiro; Kaminaga, Masanori; Kinoshita, Hidetaka; Kogawa, Hiroyuki; Sato, Hiroshi; Ishikura, Shuichi*; Torii, Yoshikatsu; Hino, Ryutaro
Proceedings of 12th International Conference on Nuclear Engineering (ICONE-12) (CD-ROM), 8 Pages, 2004/00
In the Material and Life Science Facility, which will be constructed in the J-PARC project, the spallation mercury target station will be installed. Once the target system operation starts, mercury, the target vessel and the surrounding components are highly irradiated, so that all the replacement and maintenance operations of the target vessel and its peripheral devices have to be done with remote handling. In order to meet the requirements, we designed the target system such that the target vessel and the mercury circulation system are mounted on a target trolley, which is the system carriage. The target vessel is carried with the mercury circulation system together and inserted into the target center by the target trolley during the on-beam operation. During the system maintenance period, the target trolley is withdrawn to the maintenance room of hot cell, and the component exchange or repairing work will be done using a power manipulator and some master-slave manipulators. In this paper, the present design of the mercury target and its peripheral devices for 1MW spallation neutron source including the target vessel, a mercury circulation system, and a target trolley will be reported.
Ohno, Shuji*; Miyahara, Shinya*; Kurata, Yuji
Proceedings of 12th International Conference on Nuclear Engineering (ICONE-12) (CD-ROM), 6 Pages, 2004/00
no abstracts in English
Takeda, Tetsuaki
Proceedings of 12th International Conference on Nuclear Engineering (ICONE-12) (CD-ROM), 4 Pages, 2004/00
no abstracts in English
Yamada, Seiya; Washiya, Tadahiro; Takeuchi, Masayuki; Suganuma, Takashi; Aose, Shinichi
Proceedings of 12th International Conference on Nuclear Engineering (ICONE-12) (CD-ROM), 8 Pages, 2004/00
As a part of the feasibility study on commercialized fast reactor cycle systems, Japan Nuclear Cycle Development Institute (JNC) has been developing the fuel decladding technology for the dry reprocessing process (oxide electrowinning process) and aqueous reprocessing process. Particularly, in the oxide electrowinning process, the spent fuel should be reduced to powder for quick dissolution in the molten salt at electrolyzer. Heat treatment method such as a voloxidation might not be applicable in the decladding process, because of the high plutonium content as fast reactor fuel. Therefore, JNC proposes new decladding system with innovative mechanical decradding devices. The decladding system consists of fuel crushing stage, hull separation stage and hull rinsing stage. In this paper, the outline of this new decladding system and its innovative devices will be descried.
Kitamura, Akihiro; Okada, Takashi; Asazuma, Shinichiro; Uematsu, Shinichi; Ishibashi, Takashi
Proceedings of 12th International Conference on Nuclear Engineering (ICONE-12) (CD-ROM), 6 Pages, 2004/00
The gloveboxes and process equipment used at plutonium fuel handling facilities had to bereplaced due to deterioration or change of object.
Aoshima, Atsushi; Tanaka, Kazuhiko ; Kozaka, Tetsuo
Proceedings of 12th International Conference on Nuclear Engineering (ICONE-12) (CD-ROM), 6 Pages, 2004/00
no abstracts in English
Hamada, Hirotsugu; Kurihara, Akikazu; Nishimura, Masahiro
Proceedings of 12th International Conference on Nuclear Engineering (ICONE-12) (CD-ROM), 0 Pages, 2004/00
A study of thermal influence on heat-transfer tubes in sodium-water reactions is carried out to precisely evaluate the tube rupture due to overheating in the water leak accident of an LMFBR steam generator (SG). By assuming the sodium-water reaction jet to be a two-phase flow that consists of sodium and hydrogen, the heat-transfer characteristics are examined and a simple model of effective heat-transfer coefficient (HTC) is proposed for the safety evaluation in the SG. Comparison of the model with experimental data leads to the following conclusions: An upper limit exists in the HTC between reaction jet to tube wall, and it is equivalent in approximation to the HTC of single-phase sodium flow. The HTC can be written in simpler form as functions of the HTC of single-phase sodium flow, void fraction and temperatures of sodium, hydrogen and tube wall. Hydrogen provides negligible heating effect, so that the apparent HTC would decrease with increasing of the hydrogen temperature that
Kawahara, Hirotaka; Kawahara, Hirotaka; Ichige, Satoshi; Isozaki, Kazunori; Nakai, Satoru
Proceedings of 12th International Conference on Nuclear Engineering (ICONE-12) (CD-ROM), 0 Pages, 2004/00
A recently completed major upgrade of the JOYO experimental sodium-cooled fast reactor, to the MK-III design, increased its irradiation capability approximately four times. 0ne major change was a 40% increase in thermal power to 140 MWt, which necessitated the replacement of the heat exchangers. Each of the two coolant loops includes an intermediate heat exchanger (IHX) and sodium pump in the primary system, and two dump heat exchangers (DHXs) and a pump in the secondary system. The heat transfer area of the finned tubes in each (air-cooled) DHX was doubled, compared to the old design, to achieve a 35 MWt rating, Major challenges in the replacement of secondary components, such as piping and DHX, were control of impurity ingress into the sodium system, and integrity assurance of the welding. Damage to existing components and systems was avoided during cutting and welding operations by taking measures to Prevent ingress of air into the sodium systems. The measures included use of seal b
Furukawa, Tomohiro; Furukawa, Tomohiro*; Yoshida, Eiichi; Aoto, Kazumi
Proceedings of 12th International Conference on Nuclear Engineering (ICONE-12) (CD-ROM), 49061 Pages, 2004/00
Corrosion test of three chromium-molybdenum steels -2.25Cr-1Mo, Mod.9Cr-1Mo and 12Cr-steel (ASME P122) - has been performed in stagnant lead - bismuth eutectic (LBE) at low oxygen partial pressure at 550
C up to 2,000 hours. After the test, the specimens were metallurgically examined using a scanning electron microscopy.All steels had good resistance to LBE under this test condition, and the difference of the effect of chromium concentration in the steels on corrosion behavior was not observed. Corrosion depth of the steels was a few microns, and chromium solution into LBE was observed on the surface. Very thin chromium oxide layer was partly observed on the surfaces of all steels. At the area, no corrosion was occurred. The behavior was the same as the results of martensitic steels tested in stagnant LBE containing 10-7 wt% to 10-8 wt% of oxygen.
Iguchi, Yukihiro; Tajiri, Tsuyochi; Kiyota, Shiko
Proceedings of 12th International Conference on Nuclear Engineering (ICONE-12) (CD-ROM), 0 Pages, 2003/00
The development of decommissioning for Fugen is divided into two areas. One area is development of unique technology for dismantling special components such as the reactor core and the heavy water system. Another area is improvement and enhancement of existing technologies. Especially the former area requires effort and comprises development of the reactor dismantlement, tritium decontamination of heavy water system and engineering support systems.
Ohno, Shuji; Miyahara, Shinya; Kurata, Yuji*
Proceedings of 12th International Conference on Nuclear Engineering (ICONE-12) (CD-ROM), 0 Pages, 2003/00
Evaporation behavior of lead-bismuth eutectic (LBE) and of tellurium in LBE pool is being investigated experimentally in order to obtain fundamental data on the coolant technology of accelerator driven transmutation system or fast reactor. The tellurium is used as a non-radioactive chemical surrogate of polonium which would generate and give radiological hazards in the above LBE cooled system. The experiments are conducted with the transpiration method in which saturated vapor in an isothermal evaporation pot is transported by inert carrier gas and collected outside of the pot. The LBE pool is about 500grams in mass and has a surface area of 4cm x 14cm. Two kinds of experiment are performed to measure the collected vapor mass: LBE experiment without impurity under the temperature condition of 450 to 750deg-C and LBE-tellurium experiment.The paper presents experiment outline and several instructive results such as saturated vapor pressure of LBE, information on evaporati