Applicability of statistical geometry model to light water moderating systems

Mori, Takamasa; Kojima, Kensuke*; Suyama, Kenya

JAEA-Research 2018-010, 57 Pages, 2019/02

JAEA-Research-2018-010.pdf:6.25MB

In order to estimate applicability of the statistical geometry model (STGM) of MVP/GMVP, a parametric study in infinite geometry and criticality safety analyses for direct disposal of spent fuel in simple finite geometry have been carried out by using the MVP Monte Carlo code. It has been found that calculations with STGM for larger fuel spheres give larger thermal utilization factors and larger infinite multiplication factors compared with explicit random models in the range of fuel sphere packing fraction between 6.5 % and 63.3 %. Substantial differences are not observed between the results with two nearest neighbor distributions (NNDs); that given by the MCRDF code and the analytical expression based on a statistically uniform distribution. It is inferred that the overestimation by STGM is caused by the facts that STGM cannot take account of the surroundings of each neutron, whether a fuel sphere rich region or a water moderator rich one, because STGM always uses an NND averaged over such surroundings and that STGM, therefore, cannot take the effect of consecutive scatterings in the water moderator into account.

JENDL photonuclear data file

Kishida, Norio*; Murata, Toru*; Asami, Tetsuo*; Kosako, Kazuaki*; Maki, Koichi*; Harada, Hideo*; Lee, Y.*; Chang, J.*; Chiba, Satoshi; Fukahori, Tokio

AIP Conference Proceedings 769, p.199 - 202, 2005/05

https://doi.org/10.1063/1.1944989

Nuclear data for photonuclear reactions are required in the field of shielding design of high-energy electron accelerators and high-energy -ray therapy. The JENDL Photonuclear Data File was prepared by a working group on nuclear data evaluations for photonuclear reactions in Japanese Nuclear Data Committee. From a survey of many literatures, it is difficult to construct the photonuclear data file by using only measured data, since there are not sufficient experimental data. We were therefore evaluating with theoretical calculations based on statistical nuclear reaction models. The photonuclear cross sections that are to be contained in the file are as follows: photoabsorption cross sections, yield cross sections and DDX for neutrons, protons, deuterons, tritons, He-particles and alpha-particles, and isotope production cross sections. For the actinide nuclides, photofission cross sections are also included. The maximum energy of incident photons is 140 MeV and stored are the photonuclear data for 68 nuclides from H to Np.

Nuclear data evaluation for Np, Am, Am and Am irradiated by neutrons and protons at energies up to 250 MeV

Konobeyev, A. Y.; Fukahori, Tokio; Iwamoto, Osamu

JAERI-Research 2002-032, 36 Pages, 2002/12

JAERI-Research-2002-032.pdf:1.33MB

The evaluation of nuclear data has been performed for Np, Am, Am and . Neutron data were obtained at the energies from 20 to 250 MeV and combined with JENDL-3.3 data at 20 MeV. Evaluation of the proton data has been done from 1 to 250 MeV. The coupled channel optical model was used to obtain angular distributions for elastic and inelastic scattering and transmission coefficients. Pre-equilibrium exciton model and Hauser-Feshbach statistical model were used to describe neutron and charged particles emission from the excited nuclei. These evaluation is the first work for producing the full set of evaluated file up to 250 MeV for Np and americium isotopes.

Evaluation of neutron-induced reactions on Pu for JENDL-3.3

Iwamoto, Osamu; Nakagawa, Tsuneo

JAERI-Research 2002-013, 18 Pages, 2002/07

JAERI-Research-2002-013.pdf:0.7MB

Cross sections and energy-angular distributions of emitted neutrons were evaluated for the neutron-incident reactions on Pu in the incident energy range of 10eV to 20MeV by using a statistical model combined with a coupled channel optical model. The calculated results were compiled to the latest evaluated nuclear data library JENDL-3.3 in the ENDF-6 format. The unresolved resonance region is assumed to be from 10eV to 30keV, and the averaged resonance parameters were obtained to reproduce the calculated cross sections. Maxwell temperatures for fission neutron spectra were estimated from a systematics with a correction for prefission neutrons.

Evaluation of neutron- and proton-induced nuclear data on Al up to 2GeV

Y.-O.Lee*; J.Chang*; Fukahori, Tokio; Chiba, Satoshi

Journal of Nuclear Science and Technology, 36(12), p.1125 - 1134, 1999/12

https://doi.org/10.3327/jnst.36.1125

no abstracts in English

Neutron data evaluation of U

V.M.Maslov*; Y.V.Porodzinskij*; Hasegawa, Akira; Shibata, Keiichi

JAERI-Research 98-040, 64 Pages, 1998/08

JAERI-Research-98-040.pdf:2.45MB

no abstracts in English

Continuous energy Monte Carlo calculations of randomly distributed spherical fuels in high-temperature gas-cooled reactors based on a statistical geometry model

Murata, Isao; Mori, Takamasa; Nakakawa, Masayuki

Nuclear Science and Engineering, 123, p.96 - 109, 1996/00

https://doi.org/10.13182/NSE96-A24215

no abstracts in English

Prescission and postscission charged particle emissions from the F+Tb reaction

Ikezoe, Hiroshi; Nagame, Yuichiro; *; Sugiyama, Yasuharu; Tomita, Yoshiaki; Ideno, K.; Hamada, S.; ; Iwamoto, Akira; *

Physical Review C, 49(2), p.968 - 976, 1994/02

https://doi.org/10.1103/PhysRevC.49.968

no abstracts in English

Program CASTHY: Statistical model calculation for neutron cross sections and gamma ray spectrum

*; Fukahori, Tokio

JAERI 1321, 80 Pages, 1991/03

JAERI-1321.pdf:2.14MB

no abstracts in English

Pre-scission He multiplicity in the F + Au reaction

Ikezoe, Hiroshi; Shikazono, Naomoto; Nagame, Yuichiro; Sugiyama, Yasuharu; Tomita, Yoshiaki; Ideno, K.; Iwamoto, Akira; *

Physical Review C, 42(1), p.342 - 353, 1990/07

https://doi.org/10.1103/PhysRevC.42.342

no abstracts in English