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Journal Articles

Self-shielding effect of double heterogeneity for plutonium burner HTGR design

Fukaya, Yuji; Goto, Minoru; Ohashi, Hirofumi

Annals of Nuclear Energy, 138, p.107182_1 - 107182_9, 2020/04

The investigation on self-shielding effect of double heterogeneity for plutonium burner High Temperature Gas-cooled Reactor (HTGR) design has been performed. Plutonium burner HTGR designed in the previous study by using the advantage of double heterogeneity to control excess reactivity. In the present study, the mechanism of the self-shielding effect is elucidated by the analysis of burn-up calculation and reactivity decomposition based on exact perturbation theory. As a result, it is revealed that the characteristics of burn-up reactivity are determined by resonance cross section peak at 1 eV of $$^{240}$$Pu due to the surface term of background cross section, this is, the characteristics of neutron leakage from fuel lump and collision to a moderator. Moreover, significant spectrum shift is caused during the burn-up period, and it enhances reactivity worth of $$^{239}$$Pu and $$^{240}$$Pu in EOL.

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

Preliminary experiment of neutron capture cross section of Tc-99 with lead slowing-down spectrometer

*

JNC-TJ9400 2000-009, 63 Pages, 2000/02

JNC-TJ9400-2000-009.pdf:2.48MB

The present status of nuclear data for technetium (Tc)-99, which is a well-known fission product (FP), has been reviewed and investigated. And making use of the Kyoto university Lead Slowing-down Spectrometer (KULS), the cross section of the $$^{99}$$Tc (n, $$gamma$$) $$^{100}$$Tc reaction has been measured in the energy range from thermal to keV neutron energy with an Ar-gas proportinal counter. The neutron flux/spectrum has been monitored with a BF$$_{3}$$ proportional counter, and the relative measurement has been normalized to the well-known standard capture cross section value for the $$^{99}$$Tc (n, $$gamma$$) $$^{100}$$Tc reaction at 0.0253 eV. Self-shielding corrections, especially near the resonance peaks, were made by the calculations with the MCNP code. Although the experimental data measured by Chou et al with a lead slowing-down spectrometer are higher in general, the energy dependency is similar to the present measurement. The evaluated data in ENDF/B-VI and JENDL-3.2 are higher near the resonances at 5.6 and 20 eV and above several 100 eV. A lead slowing-down spectrometer was installed coupled to a 46 MeV electron linac at the Research Reactor Institute, Kyoto university (KURRI). Characteristics of the Kyoto University Lead Slowing-down Spectrometer (KULS) were measured and (1)the relation between neutron slowing-down time t($$mu$$s) and energy E(keV) (E=190/t$$^{2}$$ in Bi hole and E=156/t$$^{2}$$ in Pb hole) and (2)the energy resolution ($$sim$$40% in Bi and Pb holes) were experimentally investigated. (3)The neutron energy spectrum in the KULS was also measured by the neutron TOF method. The results obtained by the MCNP code were in general agreement with these experimental ones.

JAEA Reports

Study on improvement of reactor physics analysis method for FBRs with various core concept

*; Kitada, Takanori*; Tagawa, Akihiro*; *; Takeda, Toshikazu*

JNC-TJ9400 2000-006, 272 Pages, 2000/02

JNC-TJ9400-2000-006.pdf:9.69MB

Investigation was made on the follwing three themes as a part of the improvement of reactor physics analysis method for FBR with various core concept. Part 1: Investigation of Error Estimation of Neutron Spectra in FBR and Suggestions to Improve the Accuracy. In order to improve the spectrum unfolding method used in fast experimental reactor JOYO, a trial was made to evaluate the error in the estimated neutron spectrum, cause by cause. And the evaluated errors were summed up to obtain the most probable and reasonable error as possible. The summed up error was found relatively small compared to the error caused by the uncertainty of cross section data: most of the error in the spectrum unfolding method can be attributed to the error in cross sections. It was also found that the error due to the fission spectrum causes a considerable error in the high energy neutron spectrum which is over several MeV. Part 2: Study on Reactor Physics Analysis Method for Gas-Cooled FBR. In gas-cooled FBR, the portion of coolant channels in core volume is larger than sodium-cooled FBR. This leads to strong neutron streaming effects. For sodium-cooled FBR, several methods were proposed to evaluate the neutron streaming effect, however, these methods can not be used directly to gas-cooled reactor because the direction dependent diffusion coefficient becomes infinitive along the direction pararel to the coolant chammel. In this study, a new method is proposed to evaluate the neutron streaming effect, based on the method taking the axial buckling into consideration, which method was originally proposed by K$"o$hler. Part 3: Study on Reactor Physics Analysis Method for Water-Cooled FBR An investigation was made on low-moderated water-cooled FBR, on the point that the ordinary used analysis method for FBR may give considerable difference in results in such core. In light water reactors, it is well known that the space dependence of self-shielding effect of heavy nuclides are considerably ...

JAEA Reports

Analysis of the Rossendorf SEG experiments using the JNC route for reactor calculation

Dietze, K.

JNC-TN9400 99-089, 20 Pages, 1999/11

JNC-TN9400-99-089.pdf:0.66MB

The integral experiments performed at the Rossendorf fast-thermal coupled reactor RRR/SEG have been reanalyzed using the JNC route for reactor calculation JENDL3.2/SLAROM / CITATION / JOINT / PERKY. The Rossendorf experiments comprise sample reactivity measurements with pure fission products and structural material in five configurations with different neutron and adjoint spectra. The shapes of the adjoint spectra have been designed to get high sensitivities to neutron capture or the scattering effect. The calculated neutron and adjoint spectra are in good agreement with former results obtained with the European route JEF2.2/ECCO/ERANOS. The C/E-values of the central reactivity worths of samples under investigation are given. Deviations in the results of both routes are due to the different libraries, codes, and self-shielding treatments used in the calculations. Results outside of the error are discussed.

Journal Articles

Approximate description of dose attenuation profiles of intermediate energy neutrons,I

Sakamoto, Yukio; *; Nakane, Yoshihiro; ; ; Tanaka, Shunichi

SATIF-2: Shielding Aspects of Accelerators,Targets and Irradiation Facilities, 0, p.147 - 156, 1996/00

no abstracts in English

JAEA Reports

The Specification and the operation characteristics of the low energy accelerator in JAERI-TRCRE

Haruyama, Yasuyuki; Yotsumoto, Keiichi; Okamoto, Jiro

JAERI-M 93-114, 46 Pages, 1993/06

JAERI-M-93-114.pdf:1.45MB

no abstracts in English

Journal Articles

Neutron total cross sections of $$^{239}$$Pufrom transmission measurements in the energy range of 1$$sim$$500 keV

H.Derrien*

Journal of Nuclear Science and Technology, 29(8), p.794 - 804, 1992/08

no abstracts in English

Journal Articles

Self-shielding factors for neutron capture reactions of uranium-238 and thorium-232 in energy range of 1$$sim$$35keV

Oigawa, Hiroyuki; Fujita, Yoshiaki*; *; Yamamoto, Shuji*; Kimura, Itsuro*

Journal of Nuclear Science and Technology, 28(10), p.879 - 893, 1991/10

no abstracts in English

JAEA Reports

JAEA Reports

None

Takeda, Toshikazu*; *; *

PNC-TJ2605 89-001, 251 Pages, 1989/03

PNC-TJ2605-89-001.pdf:4.46MB

no abstracts in English

Journal Articles

The Effect of self-shielding of the iron inelastic scattering cross section on neutron spectra

; *

Nuclear Science and Engineering, 77, p.250 - 256, 1981/00

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

no abstracts in English

JAEA Reports

Journal Articles

Estimation of Self-Shielding Effect for RI Production

;

Nippon Genshiryoku Gakkai-Shi, 12(1), p.2 - 6, 1970/00

no abstracts in English

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