Replacement of the glove box panel in the nuclear fuel reprocessing facility

Yamamoto, Masahiko; Shirozu, Hidetomo; Mori, Eito; Surugaya, Naoki

JAEA-Technology 2016-009, 58 Pages, 2016/05

JAEA-Technology-2016-009.pdf:3.95MB

The panels of glove box installed at Tokai Reprocessing Plant have been deteriorated and transparencies have been decreased due to the long-term use. Therefore, the panels have been replaced from the view point of preventive maintenance. In the new regulation formulated since the Fukushima Daiichi Nuclear Power Plant accident, it is demanded that the glove box consists of incombustible or inflammable materials. In this replacement, new panels have been manufactured with polycarbonate which satisfied the UL94 V-0 incombustible class. The inside of glove box has been contaminated with radioactive materials. Thus, the contamination and operator's exposure have been investigated. Then radiation protection equipment have been selected. Also, it is necessary to maintain the glove box enclosure during the replacement. The replacement has been conducted by covering the opening parts with vinyl sheets. The enclosure function has been verified by the inspection of the new panels and glove box.

Consideration on the earthquake-resistant margin of equipment base-bolts receiving the shearing load during seismic movements

Sakaguchi, Shinobu; Tachibana, Ikuya; Koshino, Katsuhiko; Shirozu, Hidetomo; Shirai, Nobutoshi; Imamoto, Nobuo; Tomita, Tsuneo; Tobita, Hiroo; Yamanaka, Atsushi; Kobayashi, Daisuke; et al.

JAEA-Technology 2011-006, 24 Pages, 2011/03

JAEA-Technology-2011-006.pdf:3.07MB

In the Niigataken Chuetsu-oki Earthquake on 2007, observed earthquake motion exceeded design base at the Kashiwazaki Kariwa nuclear plant. However, there was no earthquake damage in safety important equipments to stop reactor, to cool reactor, and to contain radioactive materials. One of this reason is said that many safety margin are included in the design and the permissible value. To know more accurate safety margin, shearing force examinations for the base bolts were conducted. In examinations, delegate test-bolts were made; the test bolts were selected from heavier equipment in Tokai Reprocessing Plant. In this report, the shearing strength obtained from the examinations shows more accurate safety margin.

Investigation of causes of a failed steam jet and devising an improved jet design

Shimizu, Ryo; Takaya, Akikazu; Shirozu, Hidetomo; Uchida, Naoki; Tanaka, Kosuke; Yamaguchi, Akira; Aoto, Kazumi; Watahiki, Masaru

Nihon Genshiryoku Gakkai Wabun Rombunshi, 4(3), p.203 - 212, 2005/09

https://doi.org/10.3327/taesj2002.4.203

It was occurred that process solution leaked from the steam jet in the acid recovery process of Tokai reprocessing plant. So we retrieved the jet from the cell and observed the inside. As a result, it was revealed that a defect by corrosion, which penetrated the inside of the structure, arose from the steam nozzle root in the suction room of the jet. To ascertain why such failure occurred, we carried out observation of metallurgical structure of the jet, an analysis of temperature distribution of the structure involving verification using mock-ups and evaluation of material by corrosion test. Consequently, the origin of the corrosion defect was pin hole which was occurred on the surface of the end of the material at the steam nozzle root, where nitric acid fluid was contacted, and then the defect progressed along the temperature of about 120 of the structure. Anisotropy of the material, possibly originating in the manufacturing process, was observed from the result of evaluation of material by corrosion test. Finally, we devised a new design of improved corrosion resistance on the result of the whole investigations.

Criticality safety evaluation in Tokai reprocessing plant

Shirai, Nobutoshi; ; ; Shirozu, Hidetomo; Sudo, Toshiyuki; Hayashi, Shinichiro;

JNC TN8410 2000-006, 116 Pages, 2000/04

JNC-TN8410-2000-006.pdf:2.77MB

Criticality limits for equipments in Tokai Reprocessing Plant which handle fissile material solution and are under shape and dimension control were reevaluated based on the guideline No.10 "Criticality safety of single unit" in the regulatory guide for reprocessing plant safety. This report presents criticality safety evaluation of each equipment as single unit. Criticality safety of multiple units in a cell or a room was also evaluated. The evaluated equipments were ones in dissolution, separation, purification, denitration, Pu product storage, and Pu conversion processes. As a result, it was reconfirmed that the equipments were safe enough from a view point of criticality safety of single unit and multiple units.

Stabilizing and solidifications for Pu nitrate solution at TRP, 2; Safety improvement for Tsunami and Earthquake

Miyamoto, Masanori; Shirozu, Hidetomo; Morita, Minoru; Fujisaku, Sakae; Kurita, Tsutomu; Kimura, Yuichi; Kataoka, Satoshi; Seya, Katsunori*; Sasaki, Shunichi

no journal, , 

no abstracts in English

Development of treatment for low radioactive waste in Tokai Reprocessing Plant, 28-2; Study on the effect of impurities present in waste liquid on cement solidification

Matsushima, Ryotatsu; Takahashi, Kiyofumi; Saito, Yasuo; Kikuchi, Yukihiro*; Atarashi, Daiki*; Shirozu, Hidetomo

no journal, , 

Low Active Waste Treatment Development Facility (LWTF) is planning to solidify the cement waste liquid generated at the Tokai Reprocessing Facility. In the previous report, it has been shown that the carbonate waste liquid can be solidified by conducting a solidification test on the waste liquid simulating the carbonate waste liquid containing sodium carbonate and sodium nitrate. On the other hand, it is expected that sodium sulfate will coexist as a foreign substances in the carbonate waste liquid, even though it is a trace amount, and it has been confirmed that there is no effect of sodium sulfate coexists in beaker-scale test. In this report, a actual-scale test is carried out, confirm that there is no effect when sodium sulfate coexists, and the results is reported. It was confirmed that the presence or absence of sodium sulfate in the waste liquid had no effect on the fluidity of the sample after kneading, the compressive strength of the sample after curing, etc., and thus had no effect on the solidified body properties.

Study on hydrogen generation from cement solidified products of low radioactive effluent

Sato, Fuminori; Kataoka, Shoji; Matsushima, Ryotatsu; Otake, Katsumi*; Shirozu, Hidetomo

no journal, , 

no abstracts in English

Development of treatment for low radioactive waste in Tokai Reprocessing Plant; Study on cement solidification in full-scale kneading

Kataoka, Shoji; Tsunoda, Hiroki; Matsushima, Ryotatsu; Sato, Fuminori; Shirozu, Hidetomo

no journal, , 

Low Active Waste Treatment Development Facility (LWTF) in Tokai Reprocessing Plant (TRP) is a facility for treatment of low-radioactive liquid and solid wastes generated from the TRP. The liquid wastes treated in LWTF are concentrated low-radioactive liquid waste and phosphoric acid solution, and they are planned to be solidified with cement in our new equipment. The concentrated liquid wastes are separated into slurry and carbonate compounds by a nuclide separation equipment currently in LWTF and a nitrate decomposition equipment which is under development, and then the cement solidification will be carried out on each liquid waste. Currently, studying and designing for the introduction of the nitrate decomposition equipment and cement solidification equipment is in progress. In this paper, results of the cementation demonstration on simulated waste liquids of the carbonate, phosphoric acid and slurry are reported.