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Journal Articles

Security measures at nuclear fuel facilities, 2; Internal threat countermeasure in cyber-security

Kono, Soma; Yamada, Hiroyuki; Goto, Atsushi*; Yamazaki, Katsuyuki; Nakamura, Hironobu; Kitao, Takahiko

Nihon Kaku Busshitsu Kanri Gakkai Dai-39-Kai Nenji Taikai Rombunshu (Internet), 2 Pages, 2018/11

no abstracts in English

Journal Articles

Development of cement based encapsulation for low radioactive liquid waste in Tokai Reprocessing Plant

Matsushima, Ryotatsu; Sato, Fuminori; Saito, Yasuo; Atarashi, Daiki*

Proceedings of 3rd International Symposium on Cement-based Materials for Nuclear Wastes (NUWCEM 2018) (USB Flash Drive), 4 Pages, 2018/10

At TRP, LWTF was constructed as a facility for processing low radioactive liquid waste and solid waste generated at TRP, and a cold test is been carrying out. In this facility, initially, nitrate waste liquid after separation of nuclides generated with treatment of low radioactive liquid waste was to be solidified by using borate. However, at present, it is necessary to decompose the nitrate in the liquid waste to reduce the environmental burden. For the reason, as a plan to replace the nitrate with the carbonate and to make it as a cement based encapsulation, we are studying for the introduction of the facility. Currently, as a cement solidification technology development for this liquid waste, we are studying the application of cement material based on blast furnace slag (BFS) as a main component. In this report, we show the results of the test conducted on the actual scale (200 L drum can scale).

JAEA Reports

Report on the evaluation of research and development activities in FY2014; Issue: "Research and Development on Reprocessing of Nuclear Fuel Materials" (Ex-post evaluation)

Tokai Reprocessing Technology Development Center

JAEA-Evaluation 2015-012, 83 Pages, 2015/12

JAEA-Evaluation-2015-012.pdf:6.67MB

Japan Atomic Energy Agency (hereafter referred as "JAEA") consulted the "Evaluation Committee of Research and Development Activities for Fast Reactor Cycle" to assess the issue on "Research and Development on Reprocessing of Nuclear Fuel Materials" conducted by JAEA during the period from FY2010 to FY2014. In response to the JAEA's request, the committee assessed the R&D programs and the activities of JAEA related to the issue and concluded the mission was accomplished. This evaluation was performed based on the "General guideline for the evaluation of government R&D activities", the "Guideline for evaluation of R&D in Ministry of Education, Culture, Sports, Science and Technology (MEXT)" and the "Operational rule for evaluation of R&D activities" by JAEA.

Journal Articles

Integrity check of Tokai Reprocessing Plant after the Tohoku Region Pacific Coast Earthquake

Nakano, Takafumi; Sato, Fuminori; Shirozu, Hidetomo; Nakanishi, Ryuji; Fukuda, Kazuhito; Tachibana, Ikuya

Nippon Genshiryoku Gakkai-Shi, 57(1), p.14 - 20, 2015/01

no abstracts in English

JAEA Reports

The 4th technological meeting of Tokai Reprocessing Plant

; Maki, Akira; ; ; ; ; Fukuda, Kazuhito

JNC-TN8410 2001-023, 188 Pages, 2001/11

JNC-TN8410-2001-023.pdf:30.98MB

"The 4th technological meeting of Tokai Reprocessing Plant (TRP)" was held in JNFL Rokkasyo site on octorber 11$$^{th}$$, 2001. The report contains the proceedings, transparancies and questionnaires of themeetin. This time, we reported about "Maintenance and repair results of Tokai Reprocessing Plant" based on technology and knowledge accumulated in Tokai Reprocessing Plant.

JAEA Reports

Behavior of carbon-14 in the Tokai reprocessing plant

; ; ;

JNC-TN8410 2001-021, 33 Pages, 2001/09

JNC-TN8410-2001-021.pdf:4.37MB

Carbon-14 released from the nuclear facilities is an important radionuclide for the safety assessment, because it tends to accumulate in environment through food chain and has as a significant impact to personal dose. Carbon-14 has been monitored routinely as one of the main gaseous radionuclides exhausted from the Tokai Reprocessing Plant (TRP) since OCtober of 1991. Furthermore, behavior of carbon-14 in TRP has been investigated through the reprocessing operation and the literature survey. This report describes the result of investigation about the behavior of carbon-14 in TRP as followings. (1)Only a very small amount of carbon-14 in the fuel was liberated into the shear off-gas and most of it was liberated into the dissolver of-gass. Part of the carbon-14 was trapped at the caustic scrubber installed in the of-gas treatment process, and untrapped carbon-14 was released into the environment from the main stack. Amount of carbon-14 released from the main stack was about 4.1$$sim$$6.5GBq every ton of uranium reprocessed. (2)Carbon-14 trapped at the caustic scrubbers installed in the dissolver off-gas and in the vessel off-gas treatment process is transferred to the low active waste vessel. Amount of carbon-14 transferred to the low active waste vessel was about 5.4$$sim$$ 9.6GBq every ton of uranium reprocessed. (3)The total amount of carbon-14 input to TRP was summed up to about 11.9$$sim$$15.5 GBq every ton of uranium reprocessed considering the released amount from the main stack and the trapped amount in the off-gas treatment devices. The amount of nitrogen impurity in the initial fuel was calculated about 15$$sim$$22ppm of uranium metal based on the measured carbon-14. (4)The solution in the low active waste vesselis concentrated at the evaporator.Most of the carbon-14 in the solution was transferred into concentrated solution. (5)Tokai vitrification Demonstration Facility (TVF) started to operate in 1994. Since then, carbon-14 has been measured in the ...

JAEA Reports

Annual report on the environmental radiation monitoring around Tokai reprocessing plant FY 2000

Maruo, Yoshihiro; ; Takeishi, Minoru; ; ; Takeyasu, Masanori;

JNC-TN8440 2001-011, 146 Pages, 2001/06

JNC-TN8440-2001-011.pdf:2.98MB

Environmental radiation monitoring around the Tokai Reprocessing Plant has been performed since 1975, based on "Safety Regulations for the Tokai Reprocessing Plant, Chapter IV - Environmental Monitoring". This annual report presents the results of the environmental monitoring and the dose estimation to the hypothetical inhabitants due to the radioactivity discharged from the plant during April 2000 to March 2001. Appendices present comprehensive information, such as monitoring program, monitoring results, meteorological data and annual discharges from the plant.

JAEA Reports

Study on the cause of fire and explosion incident at bituminization demonstration facility

Koyama, Tomozo; ; ; ; ; ; Shigetome, Yoshiaki

JNC-TN8410 99-027, 423 Pages, 1999/12

JNC-TN8410-99-027.pdf:22.46MB

The bituminization demonstration facility of Tokai Reprocessig Plant had a fire and explosion incident. The cause of the incident was investigated. Also, the facility condition and release of radioactive materials were evaluated. The cause of the fire and subsequent explosion was determined in a two year investigation. The main cause of the fire was that the temperature of the bituminized product rose to an unusually high temperature by a physical heating phenomena inside the extruder, which was caused by the lowering the feed rate of liquid waste. A moderate chemical reaction in the bituminized product continued and consequently the bituminized product overheated and ignited. The cause of the explosion was the accumulation of flammable gases generated from insufficiently extinguished bituminized product in the filling room in which the ventilation system had been shut down. The flammable gas was ignited by another bituminized product that overheated to the flash point temperature. This report details the condition of the facility before and after the incident, cause of the incident, and an evaluated amount of released radioactive materials.

JAEA Reports

Simulation of second fire incident in the filling room (R152)

;

JNC-TN8410 99-046, 35 Pages, 1999/10

JNC-TN8410-99-046.pdf:7.29MB

Judging from several evidences which are operators' testimony, observation result, and so on, the "Committee for an Investigation into the Fire and Explosion Incident at the BDF of the Reprocessing plant of Tokai Works" concluded another fire incident occurred in the filling room (R152) after the explosion (hereafter called second fire incident). This report explains the simulation result of second fire incident. Calculated air temperature and radiation intensity are used another calculations that indicate the thermal influence from the fire name to the extruder or neighboring drums. About second fire incident, calculated result indicates first fire occurred from the No.30104 drum that was produced in 30B or several drums including No.30104 drum. It is estimated that temperature and thermal runaway reaction was not due to fire of neighboring drum because the drum doesn't receive large influence thermally by radiation from the neighboring fire name. Each result suggests the all burnt 29B and 30B drums were filled at higher temperature than usual.

JAEA Reports

Review of design data for safety assessment of Tokai reprocessing plant; Control of hydrogen gas produced by radiolysis of reprocessing solutions at Tokai reprocessing plant

; ; ; ; Maki, Akira; Yamanouchi, Takamichi

JNC-TN8410 2000-003, 93 Pages, 1999/10

JNC-TN8410-2000-003.pdf:4.92MB

Radioactive materials in aqueous solution at a nuclear fuel reprocessing plant causes radiolytic generalion of several gases including hydrogen. Hydrogen accumulating in equipment can be an explosion hazard. In such plants, though the consideration in the design has been fundamentally made in order to remove the ignition source from the equipment, the hydrogen concentration in the equipment should not exceed the explosion threshold. It is, therefore, desired to keep the hydrogen concentration lower than the explosion threshold by diluting with the air introduced into equipment, from the viewpoint which previously prevents the explosion. This report describes the calculation of hydrogen generation, evaluation of hydrogen concentration under abnormal operation and consideration of possible improvement at Tokai Reprocessing Plant. The amount of hydrogen generation was calculated for each equipment from available data on radiolysis induced by radioactive materials. Taking into consideration for abnormal condition that is single failure of air supply and loss of power supply, the investigation was made on the method for controlling so that the hydrogen concentration may not exceed the explosion threshold. Possible means which can control the concentration of hydrogen gas under the explosion threshold have been also investigated. As the result, it was found that hydrogen concentration of most equipment was kept under the explosion threshold. It was also shown that improvement of the facility was necessary on the equipment in which the concentration of the hydrogen may exceed the explosion threshold. Proposals based on the above results are also given in this report. The above content has been described in "Examination of the hydrogen produced by the radiolysis" which is a part of "Review of Design Data for Safety Assessment of Tokai Reprocessing Plant" (JNC TN8410 99-002) published in February 1999. This report incorporates the detail evaluation so that operation ...

Oral presentation

Integrity check of Tokai Reprocessing Plant after the Tohoku Region Pacific Coast Earthquake, 3; Detailed checkup and comprehensive evaluation of installations in TRP

Fukuda, Kazuhito; Tomioka, Kenichiro*; Tachibana, Ikuya; Shirai, Nobutoshi; Kosaka, Ichiro; Nakano, Takafumi; Nagasato, Yoshihiko

no journal, , 

no abstracts in English

Oral presentation

Integrity check of Tokai Reprocessing Plant after the Tohoku Region Pacific Coast Earthquake, 1; Background and outline

Nakano, Takafumi; Fukuda, Kazuhito; Sato, Fuminori; Kosaka, Ichiro; Nagasato, Yoshihiko

no journal, , 

no abstracts in English

Oral presentation

Integrity check of Tokai Reprocessing Plant after the Tohoku Region Pacific Coast Earthquake, 5; Detailed checkup and comprehensive evaluation of buildings in TRP

Sato, Fuminori; Nakanishi, Ryuji; Kosaka, Ichiro; Nakano, Takafumi; Nagasato, Yoshihiko

no journal, , 

no abstracts in English

Oral presentation

Integrity check of Tokai Reprocessing Plant after the Tohoku Region Pacific Coast Earthquake, 2; Earthquake response analysis of installations in TRP

Koshino, Katsuhiko; Shirai, Nobutoshi; Sakaguchi, Shinobu; Shirozu, Hidetomo; Otaki, Miyuki*; Kosaka, Ichiro; Nakano, Takafumi; Nagasato, Yoshihiko; Tachibana, Ikuya

no journal, , 

no abstracts in English

Oral presentation

Integrity check of Tokai Reprocessing Plant after the Tohoku Region Pacific Coast Earthquake, 4; Earthquake response analysis of buildings in TRP

Nakanishi, Ryuji; Sato, Fuminori; Kosaka, Ichiro; Nakano, Takafumi; Nagasato, Yoshihiko

no journal, , 

no abstracts in English

Oral presentation

Development of treatment for low radioactive effluent in Tokai Reprocessing Plant 12; Small-scale experiment of cement based encapsulation

Horiguchi, Kenichi; Sato, Fuminori; Yamashita, Masaaki; Kojima, Junji; Kadota, Hirofumi*; Atarashi, Daiki*; Sakai, Etsuo*

no journal, , 

A large amount of nitrate in effluent occurring from Tokai reprocessing plant might cause environmental pollution. The effluent is planning to be encapsulated by cement after treated in the nitrate ion decomposition process. In this presentation, we will report the results of the small scale tests for cement solidification technology development of effluent containing a sodium carbonate.

Oral presentation

Development of treatment for low radioactive effluent in Tokai Reprocessing Plant, 13; Full-scale experiment of cement based encapsulation

Yamashita, Masaaki; Sato, Fuminori; Horiguchi, Kenichi; Kojima, Junji; Sakai, Etsuo*; Atarashi, Daiki*; Kadota, Hirofumi*

no journal, , 

no abstracts in English

Oral presentation

Development of treatment for low radioactive effluent in Tokai Reprocessing Plant, 11; Development plan and outline of cement based encapsulation

Sato, Fuminori; Horiguchi, Kenichi; Yamashita, Masaaki; Kojima, Junji

no journal, , 

no abstracts in English

Oral presentation

Measurement of the hydrogen concentration in the vessel off-gas generated radiolytically from Pu storage tanks

Hoshi, Takahiro; Nagaoka, Shinichi; Kudo, Atsunari; Ouchi, Masayuki; Isobe, Hiroyasu; Obu, Tomoyuki; Kurabayashi, Kazuaki

no journal, , 

no abstracts in English

Oral presentation

Study on vitrification plan of high level liquid waste in the TVF, 1; Approachs for reduction of potential hazard

Yamashita, Teruo; Matsumura, Tadayuki; Oyama, Koichi; Harashima, Takero; Ayame, Yasuo; Kodaka, Akira

no journal, , 

no abstracts in English

34 (Records 1-20 displayed on this page)