Cause investigation for thinning of anchor bolts and gaps between anchor bolt nuts and a flange plate at the JMTR Hot Laboratory exhaust stack

Shibata, Akira; Kitagishi, Shigeru; Watashi, Katsumi; Matsui, Yoshinori; Omi, Masao; Sozawa, Shizuo; Naka, Michihiro

Nihon Hozen Gakkai Dai-13-Kai Gakujutsu Koenkai Yoshishu, p.290 - 297, 2016/07

The exhaust stack of Japan Materials Testing Reactor Hot laboratory is a part of gaseous waste treatment system. It was built in 1970 and is 40 m in height. In 2015, thinning was found at some anchor bolts on base of the stack. When thinning of anchor bolts were investigated, gaps between anchor bolt nuts and flange plate was found. JAEA removed steel cylinder of stack which is 33 m in height for safety. In the end of investigation, thinning was found in all anchor bolts of the stack. Cause investigation for the thinning and the gaps were performed. It is concluded that the thinning was caused by water infiltration over a long period of time and the gaps were caused by elongation of thinning part of anchor bolts by the 2011 earthquake off the Pacific coast of Tohoku.

R&D of high-temperature resistance type mineral insulated cable for sever accident

Miura, Kuniaki*; Shibata, Hiroshi; Onizawa, Tatsuya*; Nakano, Hiroko; Takeno, Naofumi*; Takeuchi, Tomoaki; Tsuchiya, Kunihiko

Nihon Hozen Gakkai Dai-13-Kai Gakujutsu Koenkai Yoshishu, p.387 - 390, 2016/07

no abstracts in English

Physical property of seal-gasket for glove box panel in reprocessing facilities

Goto, Yuichi; Yamamoto, Masahiko; Kuno, Takehiko; Surugaya, Naoki

Nihon Hozen Gakkai Dai-13-Kai Gakujutsu Koenkai Yoshishu, p.31 - 34, 2016/07

Chloroprene rubber gaskets are often used to seal the glove box body and its panels. Such gaskets are deformed with compressive pressure and its elastic restoring force keeps sealing property. Therefore, gaskets play an important role in glove box sealing. However, physical properties of those used in glove box have not reported so far. In this study, hardness, elongation, tensile strength and compression set are investigated and its sealing performances are evaluated. The gaskets samples are taken from the glove box, which is used for 37 years. It is found that hardness, elongation and tensile strength of gaskets are changed due to the aging but its values are within the specification of chloroprene rubber. Also, the compression-set is less than the value that sealing performance is decreased. The results show that even the gaskets are used for long time, it has the property to keep sealing performances of glove box.

R&D program of maintenance technologies for the fast reactors in the sodium engineering research facility

Ueda, Masashi; Yamaguchi, Toshihiko; Saruta, Koichi

no journal, , 

no abstracts in English

Proposal of maintenance management of nuclear power plants at R&D stage by taking account of their features, 2; Case study

Chikazawa, Yoshitaka; Takaya, Shigeru; Hayashida, Kiichi*; Tagawa, Akihiro; Kubo, Shigenobu; Yamashita, Atsushi*

no journal, , 

A maintenance management suitable to nuclear power plants (NPP) at R&D stage was discussed. Objectives of maintenance management of NPP at R&D stage were first clarified. Next, applicability of codes for maintenance management of commercial NPP to NPP at R&D stage was discussed. Then, requirements and consideration for maintenance management of NPP at R&D stage was proposed. In this paper, requirements on maintenance program of NPP at R&D stage were clarified and an example that the proposal was applied to setting maintenance program of sodium-cooled fast reactor was presented.

EMAT-guided wave approach for detecting and quality evaluation of the laser beam butt welding line on the inner surface of the steel pipe

Furusawa, Akinori; Nishimura, Akihiko; Torimoto, Kazuhiro; Takenaka, Yusuke*; Saijo, Shingo*; Toyama, Ryoji*

no journal, , 

The aim of this work presented here is to investigate the applicability of the guided wave testing to detect and evaluate the quality of laser beam butt welding line. First, four test pipes were prepared. All of the pipes were laser beam butt welded from inside of the pipe using laser torch. Two pipes of them were high-quality welded, the others were low-quality. Two different pipe-wall-thicknesses were in each quality. Secondly, Laser beam butt welding line detection and the quality evaluation experiments were performed. T(0,1) mode guided wave was excited and received by electromagnetic acoustic transducer array. Finally, the experimental results were analyzed and issues concerning with the applicability of the guided wave testing to detection and quality evaluation of the laser butt welding line were discussed.

Importance of education of nuclear security and the fostering of its culture

Nakamura, Yo

no journal, ,