Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Fukushima, Masahiro; Okajima, Shigeaki*; Mukaiyama, Takehiko*
Journal of Nuclear Science and Technology, 20 Pages, 2023/00
Times Cited Count：0 Percentile：0.01(Nuclear Science & Technology)A series of integral experiments was conducted to evaluate the fission and the capture cross- sections of transuranic (TRU) nuclides at the fast critical facility FCA of the Japan Atomic Energy Agency (JAEA). The experiments were carried out using seven uranium-fueled assemblies of the FCA. The neutron energy spectra of the core regions were adjusted so as to change from an intermediate neutron spectrum to a fast neutron spectrum on an assembly-by-assembly basis. The integral data measured with these experimental configurations provide some neutron energy characteristics: 1) fission rate ratios (FRRs) of 
Np, 
Pu, 
Pu, 
Am, 
Am, and 
Cm relative to 
Pu by using absolutely calibrated fission chambers, 2) small sample reactivity worths (SRWs) of Np, Pu, 
Pu, Am, and Am where oxide powders of around 15 to 20 grams were used, 3) criticalities, and 4) spectral indices such as fission rate ratios of U relative to 
U. In this paper, details of the SRW measurements are reported, and the latest Japanese Evaluated Nuclear Data Library JENDL-5 is tested by using the integral data obtained in systematically varied neutron energy spectra.
Katano, Ryota; Oizumi, Akito; Fukushima, Masahiro; Pyeon, C. H.*; Yamamoto, Akio*; Endo, Tomohiro*
Nuclear Science and Engineering, 20 Pages, 2023/00
Times Cited Count：0 Percentile：0.01(Nuclear Science & Technology)In this study, we have demonstrated that data assimilation using lead and bismuth sample reactivities measured in the Kyoto University Critical Assembly A-core can successfully reduce the uncertainty of the coolant void reactivity in accelerator-driven systems derived from inelastic-scattering cross-sections of lead and bismuth. We re-evaluated and highlighted the experimental uncertainties and correlations of the sample reactivities for the data assimilation formula. We used the MCNP6.2 code to evaluate the sample reactivities and their uncertainties, and performed data assimilation using the reactor analysis code system MARBLE. The high-sensitivity coefficients of the sample reactivities to lead and bismuth allowed us to reduce the cross-section-induced uncertainty of the void reactivity of the accelerator-driven system from 6.3% to 4.8%, achieving a provisional target accuracy of 5% in this study. Furthermore, we demonstrated that the uncertainties arising from other dominant factors, such as minor actinides and steel, can be effectively reduced by using integral experimental data sets for the unified cross-section dataset ADJ2017.
Kitamura, Yasunori*; Fukushima, Masahiro
Nuclear Science and Engineering, 186(2), p.168 - 179, 2017/05
Times Cited Count：1 Percentile：10.58(Nuclear Science & Technology)An inconsistency between the reactivity worth of short-size samples measured by the critical-water-level (CWL) method and that conventionally analysed for validating the nuclear data and the nuclear calculation methods has been known. The present study investigated this inconsistency in terms of a simple theoretical framework and proposed a simple and practical technique for correcting the measured sample reactivity worth without making supplementary experiments. A series of Monte Carlo calculations that simulated typical sample reactivity worth measurement by the CWL method showed that this inconsistency is effectively reduced by the present correction technique.
U at FCA, I; Reactivity worth measurement with a small heated sample up to 1500
COkajima, Shigeaki; Oigawa, Hiroyuki; Mukaiyama, Takehiko; Ando, Masaki
Journal of Nuclear Science and Technology, 33(3), p.202 - 210, 1996/03
Times Cited Count：3 Percentile：32.66(Nuclear Science & Technology)no abstracts in English
Okajima, Shigeaki; Oigawa, Hiroyuki; Mukaiyama, Takehiko
Journal of Nuclear Science and Technology, 31(10), p.1097 - 1104, 1994/10
Times Cited Count：7 Percentile：56.56(Nuclear Science & Technology)no abstracts in English
C at FCAOkajima, Shigeaki; Oigawa, Hiroyuki; Mukaiyama, Takehiko; *; Kasahara, Y.*; *
Transactions of the American Nuclear Society, 66, p.523 - 524, 1992/11
no abstracts in English
Okajima, Shigeaki; Osugi, Toshitaka; Sakurai, Takeshi; *
Journal of Nuclear Science and Technology, 27(10), p.950 - 959, 1990/10
no abstracts in English
