Multiphysics analysis of reactivity changes due to solution flow in the past criticality accident at Windscale Works in 1970

Fukuda, Kodai; Yamane, Yuichi

Proceedings of 12th International Conference on Nuclear Criticality Safety (ICNC2023) (Internet), 9 Pages, 2023/10

This study presents the results of multiphysics analysis, which investigates the change of reactivity caused by the motion of fluids, of Windscale Works criticality accident. The purpose of this study is to confirm previously reported trends of emulsion formation and increase in reactivity by the multi-physics analysis which takes the motion of fluids into account. Continuous energy Monte Carlo code MVP3 was used to calculate reactivity based on the material distribution obtained by CFD calculation using OpenFOAM. An interface program in python was developed to transfer data from OpenFOAM to MVP3. The change of reactivity caused by the motion of solutions was calculated without considering the generation of heat by fissions in a system that simulated the transfer vessel at Windscale Works. As a result, trends of emulsion formation and increase in reactivity were confirmed. The influence of the resolution of the calculation system on the results was also discussed.

The Effect of final heat treatment at fabrication on the terminal solid solubility of hydrogen in Zry-4

Yamauchi, Akihiro*; Amaya, Masaki

Proceedings of Annual Topical Meeting on Reactor Fuel Performance (TopFuel 2018) (Internet), 7 Pages, 2018/10

Differential scanning calorimetry (DSC) measurements on pre-hydrided cold worked, stress relieved and recrystallized Zry-4 cladding were performed in a temperature range between 50 and 600C in order to elucidate the effect of final heat treatment at fabrication of Zircaloy-4 (Zry-4) cladding on the terminal solid solubility during the dissolution of zirconium hydrides at heating up (TSSD). Obtained DSC curves and Metallography indicate that the initial state of hydrides affects the dissolution behavior of hydride. The Arrhenius plots of the TSSD temperatures and hydrogen contents obtained from this study revealed that cold worked samples exhibited the largest TSSD and followed by stress relieved and recrystallized samples. The results of this study indicated that the difference in microstructure due to final heat treatment at fabrication of Zry-4 cladding affects the dissolution behavior of hydrides.

Characterizations of heavy ion irradiated PET membranes

Takahashi, Shuichi*; Yoshida, Masaru; Asano, Masaharu; Notomi, Mitsuo*; Nakagawa,Tsutomu*

Nuclear Instruments and Methods in Physics Research B, 217(3), p.435 - 441, 2004/05

https://doi.org/10.1016/j.nimb.2003.10.017

Various characterization were used to study the effect of heavy ion irradiation on a poly(ethylen terephthalate)(PET) membrane. My study was followed using some dynamic and thermal measurements with the aim to undestand the chemical change in the material by heavy ion irradiation. The anyalyese included DMA, tensile measurement, DSC and micro-FT-IR. The overall structure change in the PET polymer was investigated as a function of the Xe ion fluence in the range from 310 to 310ions/cm. Based on some mechanical measurements such as the tensile analysis and dynamic test, the heavy ion irradiated PET membranes exhibited a significant change in cross-linking. I believe that the secondary electron induced by collision between the irradiated ion and the constituent atoms of the membrane material form the cross-linking. The polymer chain scission and structure degradations are expected to result at higher ion fluence. Also, a slight change in the structure such as amorphization has been shown by DSC and the micro-FT-IR test.

Fabrication of prototype mockups of ITER shielding blanket with separable first wall

Kosaku, Yasuo; Kuroda, Toshimasa*; Enoeda, Mikio; Hatano, Toshihisa; Sato, Satoshi; Akiba, Masato

JAERI-Tech 2002-063, 98 Pages, 2002/07

JAERI-Tech-2002-063.pdf:11.16MB

no abstracts in English

Thermal fatigue damage of the divertor plate

Suzuki, Satoshi; Ezato, Koichiro; Sato, Kazuyoshi; Nakamura, Kazuyuki; Akiba, Masato

Fusion Engineering and Design, 49-50, p.343 - 348, 2000/11

https://doi.org/10.1016/S0920-3796(00)00394-X

no abstracts in English

Characteristics and mechanism of explosive reactions Purex solvent reactions with nitric acid at elevated temperatures (Contract research)

Miyata, Teijiro*; Takada, Junichi; Ida, Masaaki*; Nakagiri, Naotaka*; Koike, Tadao; Tsukamoto, Michio; Watanabe, Koji*; Nishio, Gunji*

JAERI-Tech 2000-035, p.64 - 0, 2000/03

JAERI-Tech-2000-035.pdf:3.17MB

no abstracts in English

Development and application of PIE apparatuses for high-burnup LWR fuels

; Mita, Naoaki; Nishino, Yasuharu; Amano, Hidetoshi

JAERI-Conf 99-009, p.103 - 111, 1999/09

https://jopss.jaea.go.jp/pdfdata/JAERI-Conf-99-009.pdf

no abstracts in English

Fabrication of an ITER shielding blanket prototype

Sato, Satoshi; Takatsu, Hideyuki; Enoeda, Mikio; Furuya, Kazuyuki; Hatano, Toshihisa; Kuroda, Toshimasa*; Osaki, Toshio*; ; Sato, Shinichi*; Ohara, Yoshihiro

Fusion Technology, 34(3), p.892 - 897, 1998/11

no abstracts in English

Thermal characteristics of microencapsulated phase-change materials

E.Choi*; Akino, Norio

Proc. of 11th Int. Heat Transfer Conf. (Heat Transfer 1998), 7, p.121 - 126, 1998/00

no abstracts in English

Radiation induced crosslinking of polytetrafluoroethylene (PTFE)

Oshima, Akihiro; Ikeda, Shigetoshi*; Seguchi, Tadao; Tabata, Yoneho*

Preprints of 6th SPSJ International Polymer Conference, P. 237, 1997/00

no abstracts in English