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Journal Articles

A Study on self-terminating behavior of sodium-concrete reaction, 2

Kawaguchi, Munemichi; Miyahara, Shinya; Uno, Masayoshi*

Journal of Nuclear Science and Technology, 55(8), p.874 - 884, 2018/08

 Times Cited Count:2 Percentile:16.17(Nuclear Science & Technology)

As parts of severe accident studies in sodium-cooled fast reactor, experiments were performed to investigate the termination mechanism of sodium-concrete reaction (SCR). In the experiment, the reaction time was controlled to investigate the distribution change of sodium (Na) and the reaction products in the pool and around the reaction front. In the results, the Na around the reaction front decreased from the enough amount with the reaction time. The concentrations were 18-24 wt.% for Na, and 22-18 wt.% for Si after the termination. From the thermodynamics calculations, the stable materials around the reaction front comprised more than 90 wt.% solid products such as Na$$_{2}$$SiO$$_{3}$$, and no Na. Further, the distribution of Na and reaction products could be explained by a steady-state sedimentation-diffusion model. At the early stage of SCR, the reaction products were suspended as particles in the Na pool because of the high H$$_{2}$$-generation rate. As the concrete ablation proceeds, they start settling down due to the decreased H$$_{2}$$-generation rate, thereby allowing SCR termination. It was concluded that SCR termination was caused by the sediment of the reaction products and the lack of Na around the reaction front.

Journal Articles

A Study on self-terminating behavior of sodium-concrete reaction

Kawaguchi, Munemichi; Doi, Daisuke; Seino, Hiroshi; Miyahara, Shinya

Journal of Nuclear Science and Technology, 53(12), p.2098 - 2107, 2016/12

 Times Cited Count:3 Percentile:42.29(Nuclear Science & Technology)

A sodium concrete reaction (SCR) is one of the important phenomena to cause the structural concrete ablation and the release of H$$_2$$ gas in the case of sever accident of sodium cooled fast reactors. In this study, the long-time SCR test had been carried out to investigate the self-termination mechanism. The results showed the SCR terminated even if the enough amount of Na remained on the concrete. The quantitative data were collected on the SCR terminating such as temperature and H$$_2$$ generation. The reaction products, which became the small solids in liquid Na were transferred with slurry state by generated H$$_2$$ bubbles. Though the Na transfers actively and ablated the concrete surface with the high H$$_2$$ generation rate, the mass exchange coefficient defined as $$E_p$$ decreased and the reaction products settled gradually with decreasing the H$$_2$$ generation rate. Therefore, the Na concentration decreased at the reaction front and resulted in the SCR terminating naturally.

JAEA Reports

Report on research and development of nuclear forensics technologies

Okubo, Ayako; Kimura, Yoshiki; Shinohara, Nobuo; Toda, Nobufumi; Funatake, Yoshio; Watahiki, Masaru; Sakurai, Satoshi; Kuno, Yusuke

JAEA-Technology 2015-001, 185 Pages, 2015/03

JAEA-Technology-2015-001.pdf:56.65MB

Nuclear forensics is the analysis of intercepted illicit nuclear or radioactive material and any associated material to provide evidence for nuclear attribution by determining origin, history, transit routes and purpose involving such material. Nuclear forensics activity includes sampling of the illicit material, analysis of the samples and evaluation of the attribution by comparing the analyzed data with database or numerical simulation. Because the nuclear forensics technologies specify the origin of the nuclear materials used illegal dealings or nuclear terrorism, it becomes possible to identify and indict offenders, hence to enhance deterrent effect against such terrorism. Worldwide network on nuclear forensics can contribute to strengthen global nuclear security regime. In this paper, the results of research and development of fundamental nuclear forensics technologies performed in Japan Atomic Energy Agency during the fiscal term of 2011-2013 were reported.

Journal Articles

Effect of neutron induced reactions of neodymium-147 and 148 on burnup evaluation

Suyama, Kenya; Mochizuki, Hiroki*

Journal of Nuclear Science and Technology, 42(7), p.661 - 669, 2005/07

 Times Cited Count:14 Percentile:26.59(Nuclear Science & Technology)

Burnup is important value for criticality safety evaluation of spent nuclear fuel. Nd-148 method is one of most important method to evaluate the burnup of post irradiation examination (PIE) samples, and well known that it has good accuracy. However, the evaluated burnup values could be perturbed by the neutron capture reaction of Nd-147 and Nd-148. And in the analysis of PIE data from PWR, the calculation results of Nd-148 have approximately more than 1% deviation from experiment. In this study, the contribution of neutron capture reaction of Nd-147 and Nd-148 to Nd-148 amount are discussed. Especially for Nd-147 contribution, it is shown that the current evaluated cross section of Nd-147 is not supported and the new evaluation is consistent with the analysis of PIE data. Possible perturbed amount of Nd-148 by both reactions is less than 0.7% for normal reactor operation condition, and it is approximately 0.1% for 30 GWd/t (BWR) and 40 GWd/t (PWR). Finally, we confirm again that Nd-148 method is good evaluation method.

Journal Articles

Site determination of the binary metal adsorbates on a single crystalline surface by means of the transmission channeling technique

Morita, Kenji*; Ishikawa, Dai*; Yuhara, J.*; Nakamura, Daisuke*; Soda, Kazuo*; Yamamoto, Shunya; Narumi, Kazumasa; Naramoto, Hiroshi; Saito, Kazuo*

JAERI-Review 99-025, TIARA Annual Report 1998, p.179 - 181, 1999/10

no abstracts in English

Journal Articles

Avoidance of VDEs during plasma current quench in JT-60U

Yoshino, Ryuji; Nakamura, Yukiharu; Neyatani, Yuzuru

Nuclear Fusion, 36(3), p.295 - 307, 1996/00

 Times Cited Count:33 Percentile:25.76(Physics, Fluids & Plasmas)

no abstracts in English

Journal Articles

Performance of the undulator for JAERI FEL project

Nagai, Ryoji; Kobayashi, Hideki*; Sasaki, Shigemi; Sawamura, Masaru; Sugimoto, Masayoshi; ; Kikuzawa, Nobuhiro; Okubo, Makio; Minehara, Eisuke; *; et al.

Nuclear Instruments and Methods in Physics Research A, 358, p.403 - 406, 1995/00

 Times Cited Count:11 Percentile:25.61

no abstracts in English

Journal Articles

An Accurate method for determining the small volumes of granular solids by mercury pycnometry

; ; Shiba, Koreyuki

J.Phys.,E, 17, p.339 - 341, 1984/00

no abstracts in English

Journal Articles

Determination of hafnium in zirconium and its alloys by a stable isotope dilution; Neutron activation analysis

;

Anal. Chem., 55(13), p.2059 - 2062, 1983/00

 Times Cited Count:13 Percentile:37.06(Chemistry, Analytical)

no abstracts in English

Journal Articles

Determination of the specific activity of fission-baced $$^{9}$$$$^{9}$$Mo using differential pulse polarography

R.K.Barnes*; E.L.R.Hetheringtone*;

Int.J.Appl.Radiat.Isot., 34(3), p.603 - 606, 1983/00

 Times Cited Count:3 Percentile:54.41

no abstracts in English

Journal Articles

A Method for determination of the $$^{1}$$$$^{5}$$$$^{2}$$Eu activity

; ; ; ;

Nuclear Instruments and Methods, 203, p.273 - 280, 1982/00

no abstracts in English

Journal Articles

Determination of coating contamination in coated particles

; Iwamoto, K.

Journal of Nuclear Science and Technology, 13(3), p.132 - 138, 1976/03

 Times Cited Count:1

no abstracts in English

Journal Articles

Rapid determination of multi-elements in thin specimens by X-rays spectrometty

Nuclear Instruments and Methods, 114(1), p.65 - 69, 1974/01

no abstracts in English

Journal Articles

Extraction-photometric determination of thorium with chlorophosphonazo-III

Analytica Chimica Acta, 63(1), p.65 - 70, 1973/01

 Times Cited Count:20

no abstracts in English

Journal Articles

Effect of Spectrum Smoothing on Peak Area Determinations

; *; *

Nuclear Instruments and Methods, 98(1), p.69 - 76, 1972/00

no abstracts in English

Journal Articles

Journal Articles

The Termination processes of the autoxidations of benzene,toluene and ethylbenzene in the aqueous phase as studied by oxygen-18

;

Bulletin of the Chemical Society of Japan, 41(7), p.1537 - 1539, 1968/00

 Times Cited Count:4

no abstracts in English

Journal Articles

Direct determination of crosslinking and chain scission in polymers

D.I.C.Kells*; ; J.E.Guillet*

J.Polym.Sci.,Part A-1, 6, p.595 - 601, 1968/00

no abstracts in English

29 (Records 1-20 displayed on this page)