Decommissioning program and future plan for Research Hot Laboratory, 2

Koya, Toshio; Nozawa, Yukio; Hanada, Yasushi; Ono, Katsuto; Kanazawa, Hiroyuki; Nihei, Yasuo; Owada, Isao

Dekomisshoningu Giho, (42), p.41 - 48, 2010/09

http://www.randec.or.jp/publish/documents/gihou/Decommissioning%20gihou_42.pdf

The Research Hot Laboratory (RHL) in Japan Atomic Energy Agency (JAEA) had been contributed to R&D program for fuels and nuclear materials in or out of JAEA. However, the decommissioning work of RHL has been started on April 2003 as the rationalization program for decrepit facilities in former Tokai institute. This work will be progressing, dismantling the lead cells and decontamination of concrete caves then release in the regulation of controlled area. The partial area of RHL will be used for the central storage of un- irradiated fuel and for temporary storage of radioactive device generated by J-PARC. The 18 lead cells had been dismantled and the preparing work for remained 20 lead cells has been finished including the removal of the applause from the cells, survey of the contamination revel in the lead cells and prediction of radio active waste. The future plan of decommissioning work has been prepared to incarnate the basic vision and dismantling procedure.

Radionuclides release from re-irradiated fuel under high temperature and pressure conditions; -ray measurements of VEGA-5 test

Hidaka, Akihide; Kudo, Tamotsu; Nakamura, Takehiko; Kanazawa, Toru; Kiuchi, Toshio; Uetsuka, Hiroshi

JAERI-Tech 2003-009, 30 Pages, 2003/03

JAERI-Tech-2003-009.pdf:1.73MB

The VEGA (Verification Experiments of radionuclides Gas/Aerosol release) program is being performed at JAERI to clarify mechanisms of radionuclides release from irradiated fuel during severe accidents and to improve source term predictability. The fifth VEGA-5 test was conducted in January 2002 to confirm the reproducibility of decrease in cesium release under elevated pressure that was observed in the VEGA-2 test and to investigate the release behavior of short-life radionuclides. The PWR fuel of 47GWd/tU after 8.2 years of cooling was re-irradiated at Nuclear Safety Research Reactor (NSRR) for 8 hours before the heat-up test. After that, the two pellets of 10.9g without cladding were heated up to about 2,900K at 1.0MPa under the inert He condition. The experiment reconfirmed the decrease in cesium release under elevated pressure. The release data on short-life radionuclides such as Ru-103 and Ba-140 that has never been observed in the previous VEGA tests without re-irradiation was obtained using the gamma ray measurement.

Detailed design of new material nitric acid recovery evaporator

Yokoyama, Hiroomi*; Kanazawa, Toshio*; Fukuma, Tadashi*; Tamekiyo, Kozo*; Yanagida, Koji*; Furuya, Takashi*; Kono, Hiroshi*; Ito, Keiji*; Shirakura, Takao*; Kashiwara, Shinichiro*; et al.

PNC TN8410 87-086VOL1, 1037 Pages, 1986/09

PNC-TN8410-87-086VOL1.pdf:34.39MB

A detailed design for a New Material Nitric Acid Recovery Evaporator was carried out with a plan to use it to replace an already constructed stainless steel Nitric Acid Recovery Evaporator at the Power Reactor and Nuclear Fuel Development Corporation's Tokai Works. Most of the original Evaporator's conditions such as compliance with applicable laws, standards, structure, treatment performance and operating conditions were maintained when designing the new machine. The material is titanium with the addition of 5% tantalum. The Evaporator was designed with an operational life expectance of 10 years. We have calculated that the new Evaporator will have sufficient strength (including a seismatic design) and have the same evaporative performance as the already constructed one. During design, we referred to the results of already completed basic designs (Phase 1) of New Material Nitric Acid Recovery Evaporators, design and production of small-scale test equipment units, and the development of successful joints between different materials. We also considered manufacturing, installation, trial runs, maintenance, and the specifications for materials used for manufacturing, installation, piping and operation of the new Evaporator.