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Journal Articles

Analyses with latest major nuclear data libraries of the fission rate ratios for several TRU nuclides in the FCA-IX experiments

Fukushima, Masahiro; Tsujimoto, Kazufumi; Okajima, Shigeaki

Journal of Nuclear Science and Technology, 54(7), p.795 - 805, 2017/07

 Times Cited Count:4 Percentile:37.79(Nuclear Science & Technology)

A series of integral experiments was conducted in FCA assemblies with systematically changed neutron spectra covering from the intermediate to fast ones. The experiments provide systematic data of central fission rates for TRU nuclides containing minor actinides, $$^{237}$$Np, $$^{238}$$Pu, $$^{239}$$Pu, $$^{242}$$Pu, $$^{241}$$Am, $$^{243}$$Am, and $$^{244}$$Cm. Latest major nuclear data libraries, JENDL-4.0, ENDF/B-VII.1, and JEFF-3.2, were tested using benchmark models regarding the fission rate ratios relative to $$^{239}$$Pu. For all the libraries, the benchmark tests by a Monte Carlo calculation code show obvious overestimations particularly for the fission rate ratios of $$^{244}$$Cm to $$^{239}$$Pu. Additionally, a large discrepancy about by 20% between the libraries is revealed for the fission rate ratio of $$^{238}$$Pu to $$^{239}$$Pu measured in the intermediate neutron spectrum. The cause of discrepancy is furthermore clarified by sensitivity analyses.

Journal Articles

Benchmark tests of newly-evaluated data of $$^{235}$$U for CIELO project using integral experiments of uranium-fueled FCA assemblies

Fukushima, Masahiro; Kitamura, Yasunori*; Yokoyama, Kenji; Iwamoto, Osamu; Nagaya, Yasunobu; Leal, L. C.*

Proceedings of International Conference on the Physics of Reactors; Unifying Theory and Experiments in the 21st Century (PHYSOR 2016) (USB Flash Drive), p.605 - 619, 2016/05

A nuclear data of $$^{235}$$U has been recently evaluated for the CIELO (Collaborative International Evaluated Library Organization) project. We tested the newly-evaluated data of $$^{235}$$U using integral experiments of the Fast Critical Assembly (FCA) performed at JAEA. We selected two integral data of uranium-fueled FCA assemblies; one is the sodium-void reactivity worth of FCA XXVII-1 assembly and the other is the criticalities of the seven assemblies of FCA IX. The benchmark tests support the evaluation done in the resonance regions. However, the $$^{235}$$U capture cross section above the unresolved resonance range needs further investigation.

Journal Articles

Fission rate ratios of FCA-IX assemblies as integral experiment for assessment of TRU's fission cross sections

Fukushima, Masahiro; Tsujimoto, Kazufumi; Okajima, Shigeaki

EPJ Web of Conferences, 111, p.07002_1 - 07002_5, 2016/03

 Times Cited Count:2 Percentile:11.05

In the IX-th series at FCA, central fission rate ratios for TRU such as $$^{237}$$Np, $$^{238}$$Pu, $$^{242}$$Pu, $$^{241}$$Am, $$^{243}$$Am, $$^{244}$$Cm and $$^{239}$$Pu were measured in the seven uranium-fueled assemblies with systematically changed neutron spectra. The FCA-IX assemblies were constructed with simplicity both in geometry and composition. Taking their advantage, benchmark models with respect to central fission rate ratios had been recently established for the assessment of the TRU's fission cross sections. By virtue of these FCA-IX assemblies where the simple combinations of uranium fuel and diluent in their core regions were systematically varied, the neutron spectra of these benchmark models cover those of various reactor types, from fast to epithermal reactors. As an application of these benchmark models, JENDL-4.0 was utilized by a Monte Carlo calculation code. Several results show obvious discrepancies between calculation and experimental values. The benchmark models would be well suited for the assessment and improvement of the nuclear data for TRU's fission cross sections.

Journal Articles

Benchmark models for criticalities of FCA-IX assemblies with systematically changed neutron spectra

Fukushima, Masahiro; Kitamura, Yasunori; Kugo, Teruhiko; Okajima, Shigeaki

Journal of Nuclear Science and Technology, 53(3), p.406 - 424, 2016/03

 Times Cited Count:8 Percentile:20.43(Nuclear Science & Technology)

JAEA Reports

Measurements of $$^{238}$$U doppler effect in the soft neutron spectra using FCA (Joint research)

Ando, Masaki; Kawasaki, Kenji*; Okajima, Shigeaki; Fukushima, Masahiro; Matsuura, Yutaka*; Kaneko, Yuji*

JAERI-Research 2005-026, 39 Pages, 2005/09

JAERI-Research-2005-026.pdf:4.37MB

$$^{238}$$U Doppler effect measurements in moderated neutron spectra (uranium fuel and MOX simulated fuel) were carried out using FCA for the purpose of contributing to the improvement in prediction accuracy for Doppler coefficient in LWR. In the mockup cores for MOX fuel, the measurements were performed in different neutron spectra, where the voidage of moderator material was varied systematically. The experimental data were obtained using cylindrical uranium samples with different outer diameter up to 800$$^{circ}$$C. Analyses were performed using a standard code system designed to analyze fast reactor mock-up experiments at FCA with the use of the JENDL-3.2 library. The results of the analyses showed that the calculation accuracy did not depend on the types of the core fuel or the Doppler samples. The calculated values agreed with the experimental ones within the experimental error. Any dependency of the prediction accuracy on the neutron spectra was not observed in the MOX simulated fuel cores.

Journal Articles

Preliminary evaluation of reduction of prediction error in breeding light water reactor core performance

Kugo, Teruhiko; Kojima, Kensuke; Ando, Masaki; Okajima, Shigeaki; Mori, Takamasa; Takeda, Toshikazu*; Kitada, Takanori*; Matsuoka, Shogo*

Proceedings of 2005 International Congress on Advances in Nuclear Power Plants (ICAPP '05) (CD-ROM), 10 Pages, 2005/05

We have preliminarily evaluated the reduction of prediction errors of the core characteristics of the breeding light water reactor core based on the bias factor method by utilizing the FCA critical experiments carried out for MOX fueled tight lattice light water reactor cores. The prediction uncertainty of k$$_{eff}$$ is reduced from 0.62% to 0.39% by utilizing the FCA-XV-2 (65V) result. As for the reaction rate ratio of $$^{238}$$U capture and $$^{239}$$Pu fission, it is found that the FCA XXII-1 (95V) and XV (95V) results are suitable for the upper core and the upper blanket of the real core and the FCA XXII-1 (65V) and XV-2 (65V) results are suitable for the lower core and the internal blanket.

JAEA Reports

Measurement and analysis of breeding index in the first mock-up core (XXII-1(65V)) for water-cooled breeder reactor at FCA (Contract research)

Fukushima, Masahiro; Okajima, Shigeaki; Ando, Masaki; Yamane, Tsuyoshi; Kataoka, Masaharu*

JAERI-Research 2005-008, 57 Pages, 2005/03

JAERI-Research-2005-008.pdf:3.49MB

no abstracts in English

JAEA Reports

Measurement of infinite multiplication factor in the mock-up core for reduced-moderation water reactor at FCA

Kojima, Kensuke; Okajima, Shigeaki; Yamane, Tsuyoshi; Ando, Masaki; Kataoka, Masaharu*; Iwanaga, Kohei

JAERI-Tech 2004-016, 38 Pages, 2004/03

JAERI-Tech-2004-016.pdf:1.46MB

To investigate the void coefficient in the Reduced-Moderation Water Reactor (RMWR), an infinite multiplication factor was measured in the FCA-XXII-1 (65V) core. Axial and radial fission rate distributions were measured by micro fission chambers with four different kinds of nuclides. The infinite multiplication factor was derived from the material buckling, which was obtained from both the axial and radial fission rate distributions, and the migration area calculated. The value of it in the test region of the FCA-XXII-1 (65V) core was 1.344$$pm$$0.034. It was compared with the calculation, the ratio of the calculation to the measurement was 1.008$$pm$$0.026. The improvement in measurement accuracy was also considered.

Journal Articles

Examination of applicability of IK method in the negative reactivity measurements

Iwanaga, Kohei; Yamane, Tsuyoshi; Nishihara, Kenji; Okajima, Shigeaki; Sekimoto, Hiroshi*; Asaoka, Takumi*

Proceedings of 11th International Conference on Nuclear Engineering (ICONE-11) (CD-ROM), 10 Pages, 2003/04

no abstracts in English

JAEA Reports

Determination of reactivity and source intensity based on the maximum likelihood method

Nishihara, Kenji; Iwanaga, Kohei; Yamane, Tsuyoshi; Okajima, Shigeaki

JAERI-Research 2002-030, 63 Pages, 2002/12

JAERI-Research-2002-030.pdf:3.81MB

During the experiments using the critical assembly such that reactivity is added to the stationary state and the core shifts to the other stationary state, the neutron flux transitionally changes after some change of the reactivity or source. Inverse kinetics method (IK method) can generally adopted as the technique of obtaining the reactivity and/or source by analyzing the neutron flux. However, the conventional analysis method was not able to obtain the solution with the maximum likelihood considering the error of the measured neutron flux and to estimate the error of the solution. In the present research, by adopting the maximum likelihood methodology to the problem, developed is the technique to obtain the reactivity and source intensity with maximum likelihood and the errors of them. Moreover, the technique is applied to the rod drops experiment in FCA, and the validity of a technique is checked.

Journal Articles

Benchmark experiment for physics parameters of nitride fuel LMFBR at FCA

Iijima, Susumu; Ando, Masaki; Oigawa, Hiroyuki

Proceedings of International Conference on the New Frontiers of Nuclear Technology; Reactor Physics, Safety and High-Performance Computing (PHYSOR 2002) (CD-ROM), 9 Pages, 2002/10

no abstracts in English

Journal Articles

Adjustment of total delayed neutron yields of $$^{235}$$U, $$^{238}$$U and $$^{239}$$Pu by using results of in-pile measurements of effective delayed neutron fraction

Sakurai, Takeshi; Okajima, Shigeaki

Proceedings of International Conference on the New Frontiers of Nuclear Technology; Reactor Physics, Safety and High-Performance Computing (PHYSOR 2002) (CD-ROM), 12 Pages, 2002/10

The cross section adjustment method was applied to total delayed neutron yields of $$^{235}$$U, $$^{238}$$U and $$^{239}$$Pu of the JENDL-3.2 file by using experimental results of effective delayed neutron fraction $$beta_{eff}$$ at six cores built in two fast critical facilities of the MASURCA and FCA and a thermal critical facility of the TCA to improve these yields. The adjustment was carried out on the yields given at several incident neutron energy points in the file. Furthermore, to validate these adjusted delayed neutron yields, analyses were performed for the $$beta_{eff}$$ experiments at ZPR fast critical facility. These adjusted yields brought a reduction of uncertainty of calculated $$beta_{eff}$$ and an improvement in agreement of $$beta_{eff}$$ between experiment and calculation.

Journal Articles

Evaluation of Delayed Neutron Data for JENDL-3.3

Yoshida, Tadashi*; Okajima, Shigeaki; Sakurai, Takeshi; Nakajima, Ken; Yamane, Tsuyoshi; Katakura, Junichi; Tahara, Yoshihisa*; Zukeran, Atsushi*; Oyamatsu, Kazuhiro*; Osawa, Takaaki*; et al.

Journal of Nuclear Science and Technology, 39(Suppl.2), p.136 - 139, 2002/08

no abstracts in English

Journal Articles

Experiments and analyses on sodium void reactivity worth in uranium-free fast reactor at FCA

Oigawa, Hiroyuki; Iijima, Susumu; Ando, Masaki

Journal of Nuclear Science and Technology, 39(7), p.729 - 735, 2002/07

 Times Cited Count:0 Percentile:100(Nuclear Science & Technology)

no abstracts in English

JAEA Reports

Conceptual study of transmutation experimental facility, 3; Study on transmutation physics experiment facility

Oigawa, Hiroyuki; Maekawa, Fujio; Meigo, Shinichiro; Kasugai, Yoshimi; Tsujimoto, Kazufumi; Nishihara, Kenji; Sasa, Toshinobu; Konno, Chikara; Kai, Tetsuya; Ikeda, Yujiro

JAERI-Tech 2002-037, 220 Pages, 2002/03

JAERI-Tech-2002-037.pdf:11.09MB

no abstracts in English

Journal Articles

Adjustment of total delayed neutron yields of $$^{235}$$U, $$^{238}$$U and $$^{239}$$Pu in JENDL-3.2 using benchmark experiments on effective delayed neutron fraction $$beta_{eff}$$

Sakurai, Takeshi; Okajima, Shigeaki

Journal of Nuclear Science and Technology, 39(1), p.19 - 30, 2002/01

 Times Cited Count:5 Percentile:63.04(Nuclear Science & Technology)

The cross section adjustment method was applied to total delayed neutron yields of $$^{235}$$U, $$^{238}$$U and $$^{239}$$Pu of the JENDL-3.2 file by using experimental results of effective delayed neutron fraction $$beta_{eff}$$ at six cores built in two fast critical facilities of the MASURCA and FCA and a thermal critical facility of the TCA to improve these yields. The adjustment was carried out on the yields given at several incident neutron energy points in the file. After the adjustment, the yield of $$^{238}$$U was almost uniformly decreased by about 3% below 7 MeV. The yield of $$^{239}$$Pu was increased by 2.6% and that of $$^{235}$$U was decreased by 0.9% at the thermal energy point, while the change of yield was less than 0.3% at the other energy points for these nuclides. By using these adjusted yields, the uncertainty of calculated $$beta_{eff}$$ was reduced and the agreement of $$beta_{eff}$$ between experiment and calculation was improved.

Journal Articles

RAPID-L highly automated fast reactor concept without any control rods, 2; Critical experiment of lithium-6 used in LEM and LIM

Tsunoda, Hirokazu*; Sato, Osamu*; Okajima, Shigeaki; Yamane, Tsuyoshi; Iijima, Susumu; Kobe, Mitsuru*

Proceedings of International Congress on Advanced Nuclear Power Plants (ICAPP) (CD-ROM), 6 Pages, 2002/00

no abstracts in English

JAEA Reports

Experiments and analyses on reactivity worth of gas expansion module (GEM) in FCA XX-1 (Joint research)

Oigawa, Hiroyuki; Ando, Masaki; Iijima, Susumu; Takaki, Naoyuki*; Uematsu, Mari Marianne*

JAERI-Research 2001-036, 48 Pages, 2001/06

JAERI-Research-2001-036.pdf:2.38MB

no abstracts in English

JAEA Reports

None

; Numata, Kazuyuki*; ; *; Oigawa, Hiroyuki*

JNC-TY9400 2000-006, 162 Pages, 2000/04

JNC-TY9400-2000-006.pdf:4.57MB

no abstracts in English

Journal Articles

Development of a standard data base for FBR core nuclear design, 12; Analysis of FCA X-1 experiments and consistency evaluation using cross-section adjustment

Yokoyama, Kenji*; Numata, Kazuyuki*; Ishikawa, Makoto*; Oigawa, Hiroyuki; Iijima, Susumu

JNC-TY9400 2000-006, 168 Pages, 2000/04

no abstracts in English

107 (Records 1-20 displayed on this page)