Sodium-cooled Fast Reactors

Ohshima, Hiroyuki; Morishita, Masaki*; Aizawa, Kosuke; Ando, Masanori; Ashida, Takashi; Chikazawa, Yoshitaka; Doda, Norihiro; Enuma, Yasuhiro; Ezure, Toshiki; Fukano, Yoshitaka; et al.

Sodium-cooled Fast Reactors; JSME Series in Thermal and Nuclear Power Generation, Vol.3, 631 Pages, 2022/07

https://shop.elsevier.com/books/sodium-cooled-fast-reactors/morishita/978-0-12-824076-2

This book is a collection of the past experience of design, construction, and operation of two reactors, the latest knowledge and technology for SFR designs, and the future prospects of SFR development in Japan. It is intended to provide the perspective and the relevant knowledge to enable readers to become more familiar with SFR technology.

Upgrade of the 3-MeV linac for testing of accelerator components at J-PARC

Kondo, Yasuhiro; Hirano, Koichiro; Ito, Takashi; Kikuzawa, Nobuhiro; Kitamura, Ryo; Morishita, Takatoshi; Oguri, Hidetomo; Okoshi, Kiyonori; Shinozaki, Shinichi; Shinto, Katsuhiro; et al.

Journal of Physics; Conference Series, 1350, p.012077_1 - 012077_7, 2019/12

https://doi.org/10.1088/1742-6596/1350/1/012077

We have upgraded a 3-MeV linac at J-PARC. The ion source is same as the J-PARC linac's, and the old 30-mA RFQ is replaced by a spare 50-mA RFQ, therefore, the beam energy is 3 MeV and the nominal beam current is 50 mA. The main purpose of this system is to test the spare RFQ, but also used for testing of various components required in order to keep the stable operation of the J-PARC accelerator. The accelerator has been already commissioned, and measurement programs have been started. In this paper, present status of this 3-MeV linac is presented.

Volume reduction of cesium contaminated soil by magnetic separation; Pretreatment of organic matters

Horie, Hiroki*; Yukumatsu, Kazuki*; Mishima, Fumihito*; Akiyama, Yoko*; Nishijima, Shigehiro*; Sekiyama, Tomio*; Mitsui, Seiichiro; Kato, Mitsugu

Journal of Physics; Conference Series, 871, p.012102_1 - 012102_7, 2017/07

https://doi.org/10.1088/1742-6596/871/1/012102

Pretreatment works for disposal of radioactive wastes produced by research activities, 1

Ishihara, Keisuke; Yokota, Akira; Kanazawa, Shingo; Iketani, Shotaro; Sudo, Tomoyuki; Myodo, Masato; Irie, Hirobumi; Kato, Mitsugu; Iseda, Hirokatsu; Kishimoto, Katsumi; et al.

JAEA-Technology 2016-024, 108 Pages, 2016/12

JAEA-Technology-2016-024.pdf:29.74MB

Radioactive isotope, nuclear fuel material and radiation generators are utilized in research institutes, universities, hospitals, private enterprises, etc. As a result, various low-level radioactive wastes (hereinafter referred to as non-nuclear radioactive wastes) are produced. Disposal site for non-nuclear radioactive wastes have not been settled yet and those wastes are stored in storage facilities of each operator for a long period. The Advanced Volume Reduction Facilities (AVRF) are built to produce waste packages so that they satisfy requirements for shallow underground disposal. In the AVRF, low-level beta-gamma solid radioactive wastes produced in the Nuclear Science Research Institute are mainly treated. To produce waste packages meeting requirements for disposal safely and efficiently, it is necessary to cut large radioactive wastes into pieces of suitable size and segregate those depending on their types of material. This report summarizes activities of pretreatment to dispose of non-nuclear radioactive wastes in the AVRF.

Zircon growth in a granitic pluton with specific mechanisms, crystallization temperatures and U-Pb ages; Implication to the "spatiotemporal" formation process of the Toki granite, central Japan

Yuguchi, Takashi*; Iwano, Hideki*; Kato, Takenori*; Sakata, Shuhei*; Hattori, Kentaro*; Hirata, Takafumi*; Sueoka, Shigeru; Danhara, Toru*; Ishibashi, Masayuki; Sasao, Eiji; et al.

Journal of Mineralogical and Petrological Sciences, 111(1), p.9 - 34, 2016/02

https://doi.org/10.2465/jmps.151007

Zircon growth collected from a granitic pluton shows four (1st - 4th) events with specific mechanisms, crystallization temperatures and U-Pb ages, revealing the sequential formation process from intrusion through emplacement to crystallization / solidification. The events are recognized by: (1) internal structure of zircon based on the cathodoluminescence observation, (2) crystallization temperatures by the Ti-in-zircon thermometer in the internal structure and (3) U-Pb ages in the internal structure.

Evaluating techniques and phenomena of Stress Corrosion Cracking (SCC) in Light Water Reactors (LWRs); SCC evaluating techniques for predicting core internal and pipe aging of LWRs, technical data collection (Contract research)

Yamamoto, Masahiro; Kato, Chiaki; Sato, Tomonori; Nakano, Junichi; Ugachi, Hirokazu; Tsukada, Takashi; Kaji, Yoshiyuki; Tsujikawa, Shigeo*; Hattori, Shigeo*; Yoshii, Tsuguyasu*; et al.

JAEA-Review 2012-007, 404 Pages, 2012/03

JAEA-Review-2012-007.pdf:36.72MB

There are many LWRs which have been operated for more than 20 years in Japan and it is expected that technique corresponding to aging plants are necessary established for safety operation in LWRs. A lot of troubles related to SCC are reported and many investigations are concerned with SCC mechanism and technical evaluation. In this paper, those research data were collected as possible widely and reviewed systematically. Current circumstances concerned with SCC in LWRs were reviewed specifically as follows: SCC incidents, SCC evaluation methods for crack initiation and propagation, the investigations concerned with SCC mechanism and monitoring technique for corrosive environment. Influences with reactor types (BWR, PWR), materials (stainless steels, Ni alloys) and SCC evaluating methods (laboratories and actual plants) were summarized as graphs and tables easy to understand in common/difference points concerned with SCC. From these arranged results, future themes were considered and remarked SCC phenomenon was summarized in actual plants. As for SCC evaluations under the accelerate conditions in the laboratory test, it was suggested that a computational prediction and modeling including statistical technique and microscopic analysis in crack initiation were important. Furthermore it was suggested that monitoring techniques predicting SCC initiation and grasping plant circumstance in operation and feasibility in actual plants were important.

Application of cathodic protection of stainless steel for components in fuel reprocessing plant

Ueno, Fumiyoshi; Uchiyama, Yohei*; Kato, Chiaki; Yamamoto, Masahiro; Ebina, Tetsunari*; Shimogawara, Shigeru*; Kano, Yoichi*

Nihon Genshiryoku Gakkai Wabun Rombunshi, 9(3), p.279 - 287, 2010/09

https://doi.org/10.3327/taesj.J09.035

An application of cathodic protection method with impressed current system to control corrosion of austenitic stainless steel in boiling nitric acid solution was studied to improve corrosion resistance of components in fuel reprocessing plant. Plate and tube type specimens made of ultra low carbon type 304 stainless steel (SUS304ULC) were immersed in boiling nitric acid solutions using electrochemical test cells, electrochemical potentiostatic tests and cathodic protection tests were performed. Corrosion rates in the solution with and without protection were measured. As the results, corrosion rates of plate type specimens with cathodic protection were decreased from 1/40 to 1/10 against without protection. In the case of tube type specimen, loss of outer surface thickness was decreased about 1/8, and no deviation of the loss was observed. Authors were concluded that cathodic protection method was expectative as one of the maintenance methods of components in fuel reprocessing plant.

Compatibility of zirconium alloy with high temperature sodium

Furukawa, Tomohiro; Kato, Shoichi; Maeda, Shigetaka

Proceedings of European Corrosion Congress 2009 (EUROCORR 2009) (CD-ROM), 8 Pages, 2009/09

Application of zirconium alloy as a neutron reflector around the driver fuel region of the Japanese experimental fast reactor JOYO has been planned for a further increase of core average burn-up. In this study, corrosion tests on the zirconium alloy bar were performed for 1000 h at 650 C and 500 C in stagnant sodium whose initial dissolved oxygen was 1 ppm. Weight gain caused by high temperature oxidation in sodium was slightly observed on the specimens. The microstructure of the specimens was the same as that of as-received specimen. No dissolution of alloy elements such as Zr, Sn, Cr and Fe into sodium was observed. Ultimate tensile strength of the exposed specimens was the same as that of as-received specimen. In fact, no effect of sodium exposure on mechanical strength was observed.

Effective thermal conductivity of MOX raw powder

Takeuchi, Kentaro; Kato, Masato; Sunaoshi, Takeo*; Aono, Shigenori; Kashimura, Motoaki

Journal of Nuclear Materials, 385(1), p.103 - 107, 2009/03

https://doi.org/10.1016/j.jnucmat.2008.09.033

The effective thermal conductivities were evaluated by measuring radial temperature distribution in MH-MOX powder. The effective thermal conductivities were very small and they changed significantly with O/M, bulk density and atmosphere gas. The results in this work were analyzed by the model of Hamilton and Crosser and the new model for the effective thermal conductivity for MH-MOX powder was derived as a function of powder properties, thermal conductivity of atmosphere gas and temperature.

Progress in R&D efforts on the energy recovery linac in Japan

Sakanaka, Shogo*; Ago, Tomonori*; Enomoto, Atsushi*; Fukuda, Shigeki*; Furukawa, Kazuro*; Furuya, Takaaki*; Haga, Kaiichi*; Harada, Kentaro*; Hiramatsu, Shigenori*; Honda, Toru*; et al.

Proceedings of 11th European Particle Accelerator Conference (EPAC '08) (CD-ROM), p.205 - 207, 2008/06

Future synchrotron light sources based on the energy-recovery linacs (ERLs) are expected to be capable of producing super-brilliant and/or ultra-short pulses of synchrotron radiation. Our Japanese collaboration team is making efforts for realizing an ERL-based hard X-ray source. We report recent progress in our R&D efforts.