First freezing experiments with a molten mixture of boron carbide and stainless steel in core disruptive accidents of sodium-cooled fast reactors

Emura, Yuki; Matsuba, Kenichi; Kikuchi, Shin; Yamano, Hidemasa

Proceedings of 13th Korea-Japan Symposium on Nuclear Thermal Hydraulics and Safety (NTHAS13) (Internet), 8 Pages, 2024/11

Thermophysical properties of austenitic stainless steel containing boron carbide in a solid state

Takai, Toshihide; Furukawa, Tomohiro; Yamano, Hidemasa

Mechanical Engineering Journal (Internet), 8(4), p.20-00540_1 - 20-00540_11, 2021/08

https://doi.org/10.1299/mej.20-00540

In a core disruptive accident scenario, boron carbide, which is used as a control rod material, may melt below the melting temperature of stainless steel owing to the eutectic reaction with them. The eutectic mixture produced is assumed to extensively relocate in the degraded core, and this behavior plays an important role in significantly reducing the neutronic reactivity. However, these behaviors have never been simulated in previous severe accident analysis. To contribute to the improvement of the core disruptive accident analysis code, the thermophysical properties of the eutectic mixture in the solid state were measured, and regression equations that show the temperature (and boron carbide concentration) dependence are created.

Thermophysical properties of stainless steel containing 5 mass%BC in the solid phase

Takai, Toshihide; Furukawa, Tomohiro; Yamano, Hidemasa

Nuclear Technology, 205(9), p.1164 - 1174, 2019/09

https://doi.org/10.1080/00295450.2019.1607136

Thermophysical properties of stainless steel containing 5mass%-BC in the solid phase

Takai, Toshihide; Furukawa, Tomohiro; Yamano, Hidemasa

Proceedings of 2018 International Congress on Advances in Nuclear Power Plants (ICAPP 2018) (CD-ROM), p.1007 - 1013, 2018/04

Examination of I and Cs releases during late phase of Fukushima Daiichi NPP accident by using I/Cs ratio of source terms evaluated reversely by WSPEEDI code with environmental monitoring data

Hidaka, Akihide; Yokoyama, Hiroya

Journal of Nuclear Science and Technology, 54(8), p.819 - 829, 2017/08

AA2016-0500.pdf:0.44MB

https://doi.org/10.1080/00223131.2017.1323691

To clarify what happened during the Fukushima accident, the phenomena within RPV and the discussion of ties with the environmental monitoring are very important. However, the previous study has not necessarily advanced until the present that passed almost six years from the accident. The present study investigated I and Cs release behaviors during the late phase of the accident based on I/Cs ratio of the source terms that were recently evaluated backward by WSPEEDI code based on environmental monitoring data. The I release from the contaminated water in the basement of 1F2 and 1F3 reactor buildings was evaluated to be about 10% of I source term. The increase in Cs release from March 21 to 23 and from March 30 to 31 could be explained by the release of CsBO which is formed as a result of chemical reactions of Cs with BC due to re-ascension of the core temperature caused by slight shortage of the core cooling water.

Boron release kinetics from mixed melts of boron carbide, stainless steel and Zircaloy; A Literature review on the behavior of control rod materials under severe accidents

Di Lemma, F. G.; Miwa, Shuhei; Osaka, Masahiko

JAEA-Review 2016-007, 27 Pages, 2016/03

JAEA-Review-2016-007.pdf:1.88MB

During a nuclear power plant Severe Accident, complex boron melts can be formed, due to interaction of the control rods with the cladding materials. These can affect ultimately the source term assessment. This review will describe the results of previous studies on boron carbide/stainless steel/Zircaloy (BC/SS/Zry) melts, which will finally provide guidance for the needs of future experiments. This review showed that models for the behavior of complex BC/SS/Zry melts are limited, and unsuccessful in simulating core degradation, thus the improvement of the database for BC/SS/Zry melts is needed. Our experimental plan aims in providing thermodynamics and kinetics models for such melts, with the final aim of improving boron modelling in SA codes analysis and of understanding its effect on fission products behavior.

Diagnostics of pulsed plasma in laser ablation of boron compounds

Oba, Hironori; Saeki, Morihisa; Yokoyama, Atsushi

Proceedings of Plasma Science Symposium 2005/22nd Symposium on Plasma Processing (PSS-2005/SPP-22), p.331 - 332, 2005/01

A plasma produced by a XeCl laser ablation of boron compound was investigated using ion probes and a quadrupole mass spectrometer. Although the ablated neutral boron atoms had a natural abundance ratio, the isotope ratio of singly ionized boron atoms having a greatly different from the natural abundance ratio was observed. The observed isotope ratio of boron ions was different from the natural abundance.

New composite composed of boron carbide and carbon fiber with high thermal conductivity for first wall

; Saido, Masahiro; Nakamura, Kazuyuki; Akiba, Masato; ; Goto, Yoshitaka*; ; ; Yamaki, Takahiro*; ; et al.

Journal of Nuclear Materials, 233-237(PT.A), p.781 - 786, 1996/00

https://doi.org/10.1016/S0022-3115(96)00306-6

no abstracts in English

Thermodynamic analysis of behavior of HTGR fuel and fission products under accidental air or water ingress conditions

Minato, Kazuo; Fukuda, Kosaku

IAEA-TECDOC-784, 0, p.86 - 91, 1995/01

no abstracts in English

Compatibility of Heat Resistant Alloys With Boron Carbide,2

; ; ; ;

JAERI-M 82-196, 29 Pages, 1982/12

JAERI-M-82-196.pdf:2.41MB

no abstracts in English