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Journal Articles

Case study on unexpected tritium release happened in a ventilated room of fusion reactor

Iwai, Yasunori; Hayashi, Takumi; Kobayashi, Kazuhiro; Nishi, Masataka

Fusion Science and Technology, 48(1), p.460 - 463, 2005/07

 Times Cited Count:4 Percentile:66.97(Nuclear Science & Technology)

A code has been developed to investigate tritium behavior in a ventilated room at its accidental release. Purpose of present study is to; (1) investigate the effect of atmospheric exchange number on confinement at initial stage of tritium release; (2) investigate the effect of atmospheric exchange number on time necessary for release detection; (3) investigate the suitable location of exhaust ducts and monitors. Essential points of discussion are as follows: (1) Atmospheric exchange number is less influential in confinement. (2) Time until a monitor detects release depends on exchange number but it is within a few minutes in any case. Installation of a monitor in each duct placed uniformly in a room is effective for the prompt detection. (3) After closing the emergency isolation valve, a few hours are needed until the tritium concentration in a room reaches uniform. Released tritium forms plume and it migrates in a room by the eddy flow at its initial stage, so it is important not to discharge plume directly. Hence, it is effective to locate exhaust ducts with some distance from the wall.

JAEA Reports

Release behavior of smoke and clogging characteristics of the ventilation filter under the fire accident (Contract research)

Takada, Junichi; Hayashi, Shiro*; Watanabe, Koji; Takita, Koji*; Tsukamoto, Michio; Tashiro, Shinsuke; Abe, Hitoshi*; Uchiyama, Gunzo*

JAERI-Tech 2002-102, 87 Pages, 2003/01

JAERI-Tech-2002-102.pdf:3.27MB

no abstracts in English

JAEA Reports

Study of technical issues on proton beam line tunnel in material/life science experimental facility of high intensity proton accelerator project

Sakamoto, Shinichi; Meigo, Shinichiro; Konno, Chikara; Harada, Masahide; Miyake, Yasuhiro*; Kasugai, Yoshimi; Muto, Suguru*; Fujimori, Satoru*; Ono, Takehiro; Ikeda, Yujiro

JAERI-Tech 2001-075, 168 Pages, 2001/12

JAERI-Tech-2001-075.pdf:12.78MB

no abstracts in English

JAEA Reports

Evaluation of released source terms from burning mock combustible waste

Abe, Hitoshi; Watanabe, Koji*; Tashiro, Shinsuke; Takada, Junichi; Uchiyama, Gunzo

JAERI-Research 2001-052, 18 Pages, 2001/11

JAERI-Research-2001-052.pdf:1.83MB

no abstracts in English

JAEA Reports

Safety demonstration tests on thermal decomposition of nitrated solvent with nitric acid in nuclear fuel reprocessing plants (Contract research)

Tsukamoto, Michio; Takada, Junichi; Koike, Tadao; Watanabe, Koji*; Miyata, Teijiro*; Nishio, Gunji*; Murata, Mikio*; Uchiyama, Gunzo

JAERI-Tech 2001-031, 47 Pages, 2001/03

JAERI-Tech-2001-031.pdf:2.75MB

no abstracts in English

JAEA Reports

Sodium pooI combustion Test (Run-F7-3 and Run-F8-1) to confirm the condition of floor liner's corrosion

; ; Ohno, Shuji;

JNC-TN9400 2000-092, 247 Pages, 2000/08

JNC-TN9400-2000-092.pdf:20.29MB

Small-scale sodium pool combustion tests Run-F7-3 and Run-F8-1 were performed to investigate the corrosion of floor liner under high moisture condition. ln the both tests, which were performed using the 3m$$^{3}$$ FRAT-1 vessel at the SAPFIRE facility, the sodium of 507deg-C was leaked on the carbon steel catch pan about for 25 minutes with the flow rate of around 25 kg/h. The air in the vessel was ventilated with the flow rate of 5m$$^{3}$$/min containing the moisture of 25000-28000 vol.ppm. The duration of combustion was different in two tests by changing the starting time of argon gas injection into the vessel. As the results of post-test analysis such as observation of catch pan surface and chemical analysis of the deposits, it was confirmed that 'Na-Fe double oxidization type corrosion' was dominant in the both tests and that the catch pan and deposits were not under the condition leading to the occurrence of 'molten salt type corrosion.'

JAEA Reports

The second maintenance report at plutonium conversion development facility

; ; *; *; *; *; *

JNC-TN8440 2000-013, 179 Pages, 2000/04

JNC-TN8440-2000-013.pdf:10.31MB

The plutonium conversion development facility (PCDF) has been operated for 17 years and about 12 tons plutonium-uranium mixed oxide (MOX) powder has been converted since operation started in 1983. The first maintenance program for aging of apparatus was carried out from 1993 to 1994. The calcination-reduction fumace, liquid waste evaporator had been dismantled and renewed. The second maintenance program was carried out form 1998 to 1999. The microwave ovens, powder blender, ventilation control panel and so on were dismantled and renewed. Large volume radioactive wastes were generated during this maintenance such as the furnace, the filter casings and glove boxes. These wastes were too large to be packed into the waste container and these wastes were polluted by MOX powder unfixed on these surface. SO cutting and packing operation for these wastes and recovery of MOX powder from them were carried out. In this report, the method of this cutting and packing operation, the radioactive exposure to the operators in this operation, the estimation of nuclear material quantity migrated to filters, the evaluation of re-floating factor of radioactive material, etc. were discussed.

JAEA Reports

Aerosol generation tests on thermal decomposition of organic solvent with nitric acid in nuclear fuel reprocessing plants (Contract research)

Tsukamoto, Michio; Takada, Junichi; Koike, Tadao; Watanabe, Koji*; Miyata, Teijiro*; Nishio, Gunji*; Murata, Mikio

JAERI-Tech 2000-036, p.43 - 0, 2000/03

JAERI-Tech-2000-036.pdf:2.27MB

no abstracts in English

Journal Articles

Low energy electron beam treatment of VOCs

Hashimoto, Shoji; Hakoda, Teruyuki; Hirota, Koichi; Arai, Hidehiko

Radiation Physics and Chemistry, 57(3-6), p.485 - 488, 2000/03

 Times Cited Count:27 Percentile:15.07

no abstracts in English

JAEA Reports

Operation system concept for high-level radioactive wastes disposal facility

*; *; Tanai, Kenji

JNC-TN8400 99-050, 94 Pages, 1999/11

JNC-TN8400-99-050.pdf:3.86MB

This paper reports on the evaluations of operational activities for a High Level Radioactive Wastes Disposal Facility, from initial acceptance of vitrified waste at a surface facility to emplacement engineered barriers in underground facilities. The purpose of this analysis is to confirm the technical feasibility of geological disposal. First, the basic design and repository system requirements are identified. Second, operational activities in surface facilities, access facilities and underground facilities are described. The required procedures and equipment, suitable for specific emplacement concepts and configurations for engineered barrier systems are discussed for specific examples. Countermeasures for potential adverse events or conditions are based on extensive civil engineering and mining experiences in Japan and abroad. The time schedule is also evaluated on the basis of these concepts. In addition, the concept of stationary and mobile radiation control areas is studied based on experiences and practice in current nuclear facilities. Finally future research and development items are summarized.

Journal Articles

Generation of smoke and clogging of ventilation filter under burning of bitumen/salt mixture

Abe, Hitoshi; Takada, Junichi; Tsukamoto, Michio; *; Murata, Mikio

Journal of Nuclear Science and Technology, 36(7), p.619 - 625, 1999/07

 Times Cited Count:0 Percentile:100(Nuclear Science & Technology)

no abstracts in English

Journal Articles

Development of electron beam treatment technology for volatile organic compounds

Hashimoto, Shoji

Haikibutsu Shori, Saishigenka No Shingijutsu, p.58 - 64, 1999/00

no abstracts in English

JAEA Reports

Three-dimensional thermofluid computer code CELVA-3D to evaluate the safety of hypothetical explosion in fuel reprocessing plants (Contract research)

Nishio, Gunji*; *; Kono, Koji*; *; Murazaki, Minoru*

JAERI-Data/Code 98-033, 235 Pages, 1998/11

JAERI-Data-Code-98-033.pdf:9.87MB

no abstracts in English

JAEA Reports

None

Kawada, Koji; ; ; ;

PNC-TN9450 97-005, 145 Pages, 1997/03

PNC-TN9450-97-005.pdf:2.48MB

None

JAEA Reports

Safety demonstration tests on pressure rise in ventilation system and blower integrity of a fuel-reprocessing plant

Takada, Junichi; Suzuki, Motoe; Tsukamoto, Michio; Koike, Tadao; *

JAERI-Tech 96-054, 237 Pages, 1996/12

JAERI-Tech-96-054.pdf:6.22MB

no abstracts in English

JAEA Reports

Safety demonstration tests of air-ventilation system for the postulated explosive burning in a cell of fuel-reprocessing plant

Takada, Junichi; Suzuki, Motoe; Tsukamoto, Michio; Koike, Tadao; Nishio, Gunji

JAERI-Tech 95-024, 339 Pages, 1995/03

JAERI-Tech-95-024.pdf:7.99MB

no abstracts in English

Journal Articles

Electron beam treatment of ventilation exhaust from tunnel

Tokunaga, Okihiro

Hoshasen To Sangyo, 0(66), p.59 - 60, 1995/00

no abstracts in English

Journal Articles

Development of the face computer code to evaluate the safety of an air ventilation system during a postulated solvent fire in a nuclear fuel reprocessing plant

Nishio, Gunji; *

Nuclear Technology, 102, p.232 - 251, 1993/05

 Times Cited Count:3 Percentile:60.66(Nuclear Science & Technology)

no abstracts in English

JAEA Reports

None

; ; ; *; ; ; *

PNC-TN8470 93-014, 72 Pages, 1993/03

PNC-TN8470-93-014.pdf:2.05MB

no abstracts in English

38 (Records 1-20 displayed on this page)