Inspection and repair techniques in the reactor vessel of the experimental fast reactor Joyo; Development of a high radiation resistance fiberscope (Joint research)

Naito, Hiroyuki; Itagaki, Wataru; Okazaki, Yoshihiro; Imaizumi, Kazuyuki; Ito, Chikara; Nagai, Akinori; Kitamura, Ryoichi; Shamoto, Naoki*; Takeshima, Yoshiyuki*

JAEA-Technology 2012-009, 100 Pages, 2012/05

JAEA-Technology-2012-009.pdf:9.89MB

The radiation characteristics of image fiber and light guide fiber were evaluated to develop a high radiation resistant fiberscope for the fast reactor in-vessel observation. It is known that a pure silica core fiber has a high radiation resistance and radiation resistance is influenced with impurities in silica. Moreover it is necessary to change the clad material of the light guide fiber because that of the current light guide fiber is acrylate, which is weak against radiation. Hence the improved fibers consist of a pure silica core with 1,000 ppm OH and fluorine-doped silica clad. As a result of a irradiation test, we confirm that OH inhibits the generation of the precursor by irradiation. About the clad material, we confirmed that the transmission loss of the fluorine-doped silica clad fiber is smaller than that of the acrylate clad fiber. About the mechanical strength of a fiber, we confirmed that there is no weakening the strength of the fiber and no exfoliation of the coating from the glass. In this study, we discovered the fiber which consists of a pure silica core with 1,000 ppm OH and fluorine-doped silica clad has a high radiation resistance and it is possible to observe using this fiber under the 200 C after 510 Gy irradiation.

Alpha radioactivity measurement based on ionized air transportation technology, 13; Influence evaluation of background drift

Aoyama, Yoshio; Miyamoto, Yasuaki; Yamaguchi, Hiromi; Izumi, Mikio*; Naito, Susumu*; Yamamoto, Shuji*; Sano, Akira*; Nambu, Kenichi*; Takahashi, Hiroyuki*; Oda, Akinori*

no journal, , 

no abstracts in English

Alpha radioactivity measurement based on ionized air transportation technology, 16; Verification test with uranium samples

Aoyama, Yoshio; Miyamoto, Yasuaki; Yamaguchi, Hiromi; Sano, Akira*; Naito, Susumu*; Sumida, Akio*; Sato, Mitsuyoshi*; Nambu, Kenichi*; Takahashi, Hiroyuki*; Oda, Akinori*

no journal, , 

no abstracts in English

Alpha radioactivity measurement based on ionized air transportation technology, 17; 3D-CFD simulations of uranium waste

Aoyama, Yoshio; Miyamoto, Yasuaki; Yamaguchi, Hiromi; Hirata, Yosuke*; Naito, Susumu*; Sano, Akira*; Nakahara, Katsuhiko*; Sato, Mitsuyoshi*; Nambu, Kenichi*; Takahashi, Hiroyuki*; et al.

no journal, , 

no abstracts in English

Development of radiation resistant fiberscope for inspection in reactor vessel of fast reactor, 2

Naito, Hiroyuki; Itagaki, Wataru; Ito, Chikara; Okazaki, Yoshihiro; Nagai, Akinori; Shamoto, Naoki*; Takeshima, Yoshiyuki*

no journal, , 

no abstracts in English

Development of a high radiaion resistant fiberscope for sensing techniques in the reactor vessel

Naito, Hiroyuki; Itagaki, Wataru; Ito, Chikara; Imaizumi, Kazuyuki; Nagai, Akinori; Tobita, Koichi

no journal, , 

no abstracts in English

Current status toward the re-operation of JMTR

Kaminaga, Masanori; Tanimoto, Masataka; Ooka, Makoto; Ishihara, Masahiro; Kusunoki, Tsuyoshi; Naito, Akinori; Araki, Masanori

no journal, , 

JMTR in JAEA is a light water cooled tank type reactor with 50MW thermal power. From its first criticality in March 1968, the JMTR has been utilized for fuel/material irradiation examinations of LWRs, HTGR and fusion reactor as well as for RI productions under its transportation advantage that the JMTR and hot laboratory is connected by a canal. In August 2006, the JMTR operation was once stopped in order to have a check & review for the reoperation which was discussed by internal as well as external committees. As a result of the national discussion, the JMTR was determined, finally, to restart after necessary refurbishment works. The refurbishment was started from the beginning of JFY 2007, and replaced were motors of primary and secondary cooling pumps, nuclear instrumentation system, and so on. The refurbishment was finished in March 2011 as planned. Unfortunately, at the end of the JFY 2010 on March 11, the Great-Eastern-Japan-Earthquake occurred, and functional tests before the JMTR restart were delayed by the earthquake. Seismic influence evaluation for the JMTR because of the 3.11 earthquake was carried out with directions of the government. As a result, integrity of the JMTR reactor facilities has been evaluated and verified for re-operation. Seismic influence evaluation results were reported to the regulatory agency on Sep.7, 2012. Validation evaluation of the seismic influence evaluation results is still underway by the NRA. On the other hand, new regulatory requirements for research and test reactors will be established on Dec.18, 2013 by the NRA. JMTR will be re-started after the completion of validation evaluation of the seismic influence evaluation results and confirmation of suitability against the new regulatory requirements for research and test reactors by the NRA. The renewed JMTR will be operated for a period of about 20 years until around JFY 2030.