Materials science and fuel technologies of uranium and plutonium mixed oxide

Kato, Masato; Machida, Masahiko; Hirooka, Shun; Nakamichi, Shinya; Ikusawa, Yoshihisa; Nakamura, Hiroki; Kobayashi, Keita; Ozawa, Takayuki; Maeda, Koji; Sasaki, Shinji; et al.

Materials Science and Fuel Technologies of Uranium and Plutonium mixed Oxide, 171 Pages, 2022/10

https://doi.org/10.1201/9781003298205

Innovative and advanced nuclear reactors using plutonium fuel has been developed in each country. In order to develop a new nuclear fuel, irradiation tests are indispensable, and it is necessary to demonstrate the performance and safety of nuclear fuels. If we can develop a technology that accurately simulates irradiation behavior as a technology that complements the irradiation test, the cost, time, and labor involved in nuclear fuel research and development will be greatly reduced. And safety and reliability can be significantly improved through simulation of nuclear fuel irradiation behavior. In order to evaluate the performance of nuclear fuel, it is necessary to know the physical and chemical properties of the fuel at high temperatures. And it is indispensable to develop a behavior model that describes various phenomena that occur during irradiation. In previous research and development, empirical methods with fitting parameters have been used in many parts of model development. However, empirical techniques can give very different results in areas where there is no data. Therefore, the purpose of this study is to construct a scientific descriptive model that can extrapolate the basic characteristics of fuel to the composition and temperature, and to develop an irradiation behavior analysis code to which the model is applied.

Development of an unstable failure analysis procedure considering change of compliance at a crack part of SFR pipes

Wakai, Takashi; Machida, Hideo*; Yoshida, Shinji*; Yanagihara, Seiji*; Suzuki, Ryosuke*; Matsubara, Masaaki*; Enuma, Yasuhiro

Engineering Failure Analysis, 56, p.484 - 500, 2015/10

https://doi.org/10.1016/j.engfailanal.2014.11.021

Demonstration of Leak-Before-Break in Japan sodium cooled fast reactor (JSFR) pipes

Wakai, Takashi; Machida, Hideo*; Yoshida, Shinji*; Xu, Y.*; Tsukimori, Kazuyuki

Nuclear Engineering and Design, 269, p.88 - 96, 2014/04

https://doi.org/10.1016/j.nucengdes.2013.08.012

Development of leak-before-break assessment method for Japan Sodium cooled Fast Reactor pipe, 1; Crack opening displacement assessment of thin wall pipes made of modified 9Cr-1Mo steel

Wakai, Takashi; Machida, Hideo*; Arakawa, Manabu*; Yoshida, Shinji*; Enuma, Yasuhiro

Journal of Pressure Vessel Technology, 135(1), p.011401_1 - 011401_9, 2013/02

https://doi.org/10.1115/1.4007642

This was carried out to establish crack opening displacement (COD) evaluation methods used in Leak-Before-Break (LBB) assessment of sodium pipes of the Japan Sodium cooled Fast Reactor (JSFR). A COD assessment method applicable to thin walled large diameter pipe made of modified 9Cr-1Mo steel was proposed in this study. In this method, COD was calculated by classifying the components of COD; elastic, local plastic and fully plastic. In addition, the verification of this method was performed by comparing with the results of a series of four-point bending tests at elevated temperature using thin wall modified 9Cr-1Mo steel pipe containing a circumferential through wall crack. The rational leak rate evaluation method in LBB assessment was proposed.

Effect of rotational stiffness evolution at crack part on critical crack size in SFR

Wakai, Takashi; Machida, Hideo*; Yoshida, Shinji*

Proceedings of 2012 ASME Pressure Vessels and Piping Conference (PVP 2012) (DVD-ROM), 9 Pages, 2012/07

This paper describes the efficiency of the deployment of rotational stiffness evolution model in the critical crack size evaluation for Leak Before Break (LBB) assessment of Sodium cooled Fast Reactor (SFR) pipes. The authors have developed a critical crack size evaluation method for the thin-walled large diameter pipe made of modified 9Cr-1Mo steel. In this method, since the SFR pipe is mainly subjected to displacement controlled load caused by thermal expansion, the stress at the crack part is estimated taking stiffness evolution due to crack into account. The stiffness evolution is evaluated by using the rotational spring model. In this study, critical crack sizes for several pipes having some elbows were evaluated and discuss about the effect of the deployment of the stiffness evolution model at the crack part on critical crack size. As a result, the critical crack size increases by employing the model and LBB range may be expected to be enlarged.

Single-alpha-particle-induced charge transient spectroscopy of the 6H-SiC pn diode irradiated with high-energy electrons

Iwamoto, Naoya; Koizumi, Atsushi*; Onoda, Shinobu; Makino, Takahiro; Oshima, Takeshi; Kojima, Kazutoshi*; Koike, Shumpei*; Uchida, Kazuo*; Nozaki, Shinji*

IEEE Transactions on Nuclear Science, 58(6), p.3328 - 3332, 2011/12

https://doi.org/10.1109/TNS.2011.2167631

no abstracts in English

Development of LBB assessment method for Japan Sodium Cooled Fast Reactor (JSFR) pipes, 4; Verification of crack opening displacement assessment method for thin wall pipes made of Mod.9Cr-1Mo steel

Wakai, Takashi; Machida, Hideo*; Yoshida, Shinji*; Kawashima, Fumiko*; Kikuchi, Koichi*; Xu, Y.*; Tsukimori, Kazuyuki

Proceedings of 2011 ASME Pressure Vessels and Piping Conference (PVP 2011) (CD-ROM), 10 Pages, 2011/07

This paper describes the improved COD assessment method and verifies the validity of the method based on the results of a series of four-point bending tests at elevated temperature using thin wall modified 9Cr-1Mo steel pipe containing a circumferential through wall crack. As a result, COD values calculated by the proposed method were in a good agreement with the experimental results for the uniform pipe without weld. In the case that the crack was machined at weld metal or heat affected zone (HAZ), proposed method predicted relatively larger COD than the experimental results. The causes of such discrepancies were discussed comparing with the results of finite element analyses. Based on these examinations, the rational leak rate evaluation method in LBB assessment was proposed.

Transient analysis of an extended drift region in a 6H-SiC diode formed by a single alpha particle strike and its contribution to the increased charge collection

Iwamoto, Naoya; Onoda, Shinobu; Makino, Takahiro; Oshima, Takeshi; Kojima, Kazutoshi*; Koizumi, Atsushi*; Uchida, Kazuo*; Nozaki, Shinji*

IEEE Transactions on Nuclear Science, 58(1), p.305 - 313, 2011/02

https://doi.org/10.1109/TNS.2010.2096432

no abstracts in English

Time-dependent collected charges of 6H-SiC pn diodes measured using alpha particles

Iwamoto, Naoya; Onoda, Shinobu; Makino, Takahiro; Oshima, Takeshi; Kojima, Kazutoshi*; Koizumi, Atsushi*; Uchida, Kazuo*; Nozaki, Shinji*

Proceedings of 9th International Workshop on Radiation Effects on Semiconductor Devices for Space Applications (RASEDA-9), p.222 - 225, 2010/10

Charge collection efficiency of 6H-SiC PN diodes degraded by low-energy electron irradiation

Iwamoto, Naoya; Onoda, Shinobu; Oshima, Takeshi; Kojima, Kazutoshi*; Koizumi, Atsushi*; Uchida, Kazuo*; Nozaki, Shinji*

Materials Science Forum, 645-648, p.921 - 924, 2010/00

Electron irradiation effects on the charge collection efficiency (CCE) of the 6H-SiC pn diodes were investigated. The diodes were irradiated with electrons at energies from 100 keV to 1 MeV. The value of CCE of the diodes using alpha particles compared before and after the electron irradiations. In the case of 100 keV electron, no significant change in CCE was observed. On the other hand, above 200 keV, the values of CCE decreased with increasing fluence. The degradation was larger with increasing incident electron energy.