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Lind, T.*; Herranz, L. E.*; Sonnenkalb, M.*; Maruyama, Yu
Proceedings of 19th International Topical Meeting on Nuclear Reactor Thermal Hydraulics (NURETH-19) (Internet), 15 Pages, 2022/03
Shi, D.*; Xhonneux, A.*; Ueta, Shohei; Verfondern, K.*; Allelein, H.-J.*
Proceedings of 7th International Topical Meeting on High Temperature Reactor Technology (HTR 2014) (USB Flash Drive), 11 Pages, 2014/10
Demonstration tests were conducted using the High Temperature Engineering Test Reactor (HTTR) in Oarai, Japan, to confirm the safety of HTGR technologies and assure the expected physical phenomena to occur under given conditions. As part of the OECD directed LOFC (loss of forced cooling) project, a series of three tests at the HTTR has been planned with tripping of all gas circulators while deactivating all reactor reactivity control to disallow reactor scram due to abnormal reduction of primary coolant flow rate. The tests fall into anticipated transient without scram (ATWS) with occurrence of reactor recriticality. The paper will describe the Source Term Analysis Code System (STACY) newly developed at the Research Center J
lich and present the results of fission product behavior in the HTTR core under the LOFC test conditions. STACY encompasses the original verified and validated computer models for simulating fission product transport and release. For verification of the modernized and extended version, it was assured that results obtained with the original tools could be reproduced. One of the new features of STACY is its ability to also treat fuel compacts of (full) cylindrical or annular shape and a complete prismatic block reactor core, respectively, supposed sufficient input data be available. In the paper, calculations are based on time-dependent neutronics and fluid dynamics results obtained with the Serpent and MGT models.
Nagaya, Yasunobu; Mori, Takamasa
Journal of Nuclear Science and Technology, 42(5), p.428 - 441, 2005/05
Times Cited Count：61 Percentile：95.82(Nuclear Science & Technology)A new method to estimate a change in the effective multiplication factor due to the perturbed fission source distribution has been proposed for Monte Carlo perturbation calculations with the correlated sampling and differential operator sampling techniques. The method has been implemented into the MVP code for verification. Simple benchmark problems have been set up for fast and thermal systems and the applicability of the method has been verified with the problems. In consequence, it has been confirmed that the method is very effective to estimate the change. It has been also shown that there are some cases where the perturbed source effect is significant and the change in reactivity cannot be estimated accurately without taking the effect into account. Even in such cases, the new method can estimate the perturbed source effect and the estimation of the change in reactivity has been remarkably improved.
Kuroishi, Takeshi; Nomura, Yasushi
Journal of Nuclear Science and Technology, 40(6), p.433 - 440, 2003/06
Times Cited Count：2 Percentile：18.9(Nuclear Science & Technology)Effective source acceleration method is studied in criticality safety analysis for realistic spent fuel transport cask. Various axial burnup profiles based on in-core flux measurements are proposed in the OECD/NEA/BUC benchmark Phase II-C. In some cases, calculations by ordinary Monte Carlo method show very slow convergence of fission source distribution, and unacceptably large skipped cycles are needed. The matrix eigenvector calculation that has been developed and incorporated in the ordinary Monte Carlo calculation to improve the slow convergence is applied to the benchmark. The efficiency of this method depends on the precision of matrix elements. In a certain stage of insufficient convergence of fission source distribution, especially for this benchmark of very slow convergence, more acceleration procedure causes anomalous results because of large statistical fluctuations of matrix elements corresponding to low source levels. Therefore, we propose effective source acceleration method with less calculation time than increasing histories for the estimation of matrix elements.
Kuroishi, Takeshi; Nomura, Yasushi
Proceedings of International Conference on the New Frontiers of Nuclear Technology; Reactor Physics, Safety and High-Performance Computing (PHYSOR 2002) (CD-ROM), 10 Pages, 2002/10
To accelerate the slow convergence of the fission source distribution, the matrix k calculation has been developed and incorporated in the ordinary Monte Carlo method. The acceleration can be performed by the fission source correction using the eigenvector of the fission matrix, if the coupling coefficients are approximately evaluated in the middle of Monte Carlo calculation. In this paper, we propose two effective applications of the matrix k, that is, the acceleration repetition method and the source generation method. The former simply repeats the matrix k calculation, and the result for the irradiated fuel pin cell shows enough effective to accelerate the fission source on the criticality estimation. However, in some cases of the loosely coupled multi unit system, the repetition of matrix k more than twice could not be carried out to get into convergence because of many units of low source level. The latter is newly devised here to apply to such cases. The checkerboard fuel storage rack is one of the typical cases, and the calculated results show the effectiveness of this method.
-energy analysis system for fuel and fission gas behavior during High Temperature Engineering Test Reactor operationUeta, Shohei; Tobita, Tsutomu*; Takahashi, Masashi*; Sawa, Kazuhiro
JAERI-Tech 2002-055, 24 Pages, 2002/07
JAERI-Tech-2002-055.pdf:1.04MB
no abstracts in English
Yamauchi, Michinori*; Nishitani, Takeo; Ochiai, Kentaro; Morimoto, Yuichi*; Hori, Junichi; Ebisawa, Katsuyuki*; Kasai, Satoshi
JAERI-Tech 2002-032, 41 Pages, 2002/03
JAERI-Tech-2002-032.pdf:2.62MB
A micro-fission chamber and a dummy chamber without uranium were fabricated and the performance was tested. They are designed to be installed inside the vacuum vessel of compact ITER (ITER-FEAT) for neutron monitoring. Vacuum leak rate of the chamber, resistances between central conductor and outer sheath, and mechanical strength up to 50G acceleration were confirmed to meet design criteria. Gamma-ray sensitivity was measured with 
Co gamma-ray irradiation facility at JAERI Takasaki. The output signals for gamma-rays in Campbelling mode were estimated to be less than 0.1% those by neutrons at the location behind the blanket module in ITER-FEAT. Detector response for 14 MeV neutrons was investigated with the FNS facility. Excellent linearity between count rates and neutron fluxes was confirmed. According to the test for the change of surrounding materials, the sensitivity was enhanced by slow-downed neutrons, which agreed with the calculation result by MCNP-4C code. As a result, it was concluded that the developed micro-fission chamber is applicable for ITER-FEAT.
Hashimoto, Kazuichiro
JAERI-Conf 2000-015, 363 Pages, 2000/11
JAERI-Conf-2000-015.pdf:29.26MB
no abstracts in English
Nagaya, Yasunobu; Mori, Takamasa
Proceedings of the ANS International Topical Meeting on Advances in Reactor Physics and Mathematics and Computation into the Next Millennium (PHYSOR2000) (CD-ROM), p.13 - 0, 2000/00
no abstracts in English
Sugimoto, Jun
JAERI-Conf 99-005, 523 Pages, 1999/07
no abstracts in English
Nakamura, Takehiko; Hidaka, Akihide; Hashimoto, Kazuichiro; Harada, Yuhei; Nishino, Yasuharu; Kanazawa, Hiroyuki; Uetsuka, Hiroshi; Sugimoto, Jun
JAERI-Tech 99-036, 34 Pages, 1999/03
no abstracts in English
Sugimoto, Jun
JAERI-Conf 98-009, 501 Pages, 1998/05
no abstracts in English
*; J.Huang*; *; *; *; Yamaguchi, Kenji*; Sugimoto, Jun
JAERI-Tech 98-003, 32 Pages, 1998/02
no abstracts in English
Konno, Chikara; Maekawa, Fujio; Oyama, Yukio; Ikeda, Yujiro; Kosako, Kazuaki*; Maekawa, Hiroshi
JAERI-Research 94-043, 96 Pages, 1994/12
JAERI-Research-94-043.pdf:3.5MB
no abstracts in English
Cf neutron sourceNishitani, Takeo; Takeuchi, Hiroshi; Kondoh, Takashi; Ito, Takao*; Kuriyama, Masaaki; Ikeda, Yujiro; Iguchi, Tetsuo*; Barnes, C. W.*
Review of Scientific Instruments, 63(11), p.5270 - 5278, 1992/11
Times Cited Count：76 Percentile：97.13(Instruments & Instrumentation)no abstracts in English
Konno, Chikara; Maekawa, Fujio; Ikeda, Yujiro; Oyama, Yukio; Kosako, Kazuaki*; Maekawa, Hiroshi
Fusion Technology, 21(3), p.2169 - 2173, 1992/05
no abstracts in English
Konno, Chikara; Maekawa, Fujio; Ikeda, Yujiro; Oyama, Yukio; Kosako, Kazuaki*; Maekawa, Hiroshi
JAERI-M 92-027, p.290 - 297, 1992/03
no abstracts in English
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Genshikaku Kenkyu, 29(6), p.121 - 129, 1985/00
no abstracts in English
; ; *; ; ;
JAERI-M 84-227, 19 Pages, 1984/12
no abstracts in English
JAERI-M 9757, 18 Pages, 1981/10
no abstracts in English
