Estimation of continuous distribution of iterated fission probability using an artificial neural network with Monte Carlo-based training data

Tuya, D.; Nagaya, Yasunobu

Journal of Nuclear Engineering (Internet), 4(4), p.691 - 710, 2023/11

https://doi.org/10.3390/jne4040043

The Monte Carlo method is used to accurately estimate various quantities such as k-eigenvalue and integral neutron flux. However, when a distribution of a quantity is desired, the Monte Carlo method does not typically provide continuous distribution. Recently, the functional expansion tally and kernel density estimation methods have been developed to provide continuous distribution. In this paper, we propose a method to estimate a continuous distribution of a quantity using artificial neural network (ANN) model with Monte Carlo-based training data. As a proof of concept, a continuous distribution of iterated fission probability (IFP) is estimated by ANN models in two systems. The IFP distributions by the ANN models were compared with the Monte Carlo-based data and the adjoint angular neutron fluxes by the PARTISN code. The comparisons showed varying degrees of agreement or discrepancy; however, it was observed that the ANN models learned the general trend of the IFP distributions.

Chemical reaction kinetics dataset of Cs-I-B-Mo-O-H system for evaluation of fission product chemistry under LWR severe accident conditions

Miyahara, Naoya; Miwa, Shuhei; Horiguchi, Naoki; Sato, Isamu*; Osaka, Masahiko

Journal of Nuclear Science and Technology, 56(2), p.228 - 240, 2019/02

https://doi.org/10.1080/00223131.2018.1544939

In order to improve LWR source term under severe accident conditions, the first version of a fission product (FP) chemistry database named "ECUME" was developed. The ECUME is intended to include major chemical reactions and their effective kinetic constants for representative SA sequences. It is expected that the ECUME can serve as a fundamental basis from which FP chemical models in the SA analysis codes can be elaborated. The implemented chemical reactions in the first version were those for representative gas species in Cs-I-B-Mo-O-H system. The chemical reaction kinetic constants were evaluated from either literature data or calculated values using ab-initio calculations. The sample chemical reaction calculation using the presently constructed dataset showed meaningful kinetics effects at 1000 K. Comparison of the chemical equilibrium compositions by using the dataset with those by chemical equilibrium calculations has shown rather good consistency for the representative Cs-I-B-Mo-O-H species. From these results, it was concluded that the present dataset should be useful to evaluate FP chemistry in Cs-I-B-Mo-O-H system under LWA SA conditions.

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

https://doi.org/10.1051/epjconf/201611107002

In the IX-th series at FCA, central fission rate ratios for TRU such as Np, Pu, Pu, Am, Am, Cm and 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.

Influence of uranium enrichment on the etching rate of polycarbonate fission track detector containing uranium particles

Lee, C. G.; Iguchi, Kazunari; Esaka, Fumitaka; Magara, Masaaki; Sakurai, Satoshi; Watanabe, Kazuo; Usuda, Shigekazu

Nuclear Instruments and Methods in Physics Research B, 245(2), p.440 - 444, 2006/04

https://doi.org/10.1016/j.nimb.2005.11.002

The etching rates of fission track detectors made of polycarbonate containing uranium particles were measured after thermal neutron irradiation with fluence of 810 n/cm, in order to study the influence of uranium enrichment on the etching rate that was calculated from the weight loss by etching. There is a strong correlation between the etching rate of detector and the enrichment E of uranium particle: the former increases as the latter increases. Particularly, the etching rate per particle was proportional to E rather than E, which is probably due to the overlapping of fission tracks. The etching behaviors of detector revealed that the existence of two different etching rate regions, a nonlinear region in the beginning of etching process and a subsequent constant region, which was explained as the opening of fission tracks and the broadening of opened tracks, respectively.

Benchmark experiments for absorbed dose in a slab phantom for several tens MeV neutrons at the TIARA facility

Nakane, Yoshihiro; Sakamoto, Yukio

Proceedings of 5th Specialists' Meeting on Shielding Aspects of Accelerators, Targets and Irradiation Facilities (SATIF-5), p.241 - 252, 2000/00

no abstracts in English

In-Vessel neutron monitor using micro fission chambers for ITER

Nishitani, Takeo; Ebisawa, Katsuyuki*; C.Walker*; ; Kasai, Satoshi; L.C.Johnson*

Proc. of Int. Workshop on Diagnostics for Experimental Fusion Reactors, p.491 - 500, 1998/00

no abstracts in English

Modified conversion ratio measurement in light water-moderated UO lattices

Nakajima, Ken;

Nuclear Technology, 113, p.375 - 379, 1996/03

https://doi.org/10.13182/NT96-A35217

no abstracts in English

Bulk shielding experiment on a large SS316/water assembly bombarded by D-T neutrons, volume I; Experiment

Konno, Chikara; Maekawa, Fujio; Oyama, Yukio; Ikeda, Yujiro; Uno, Yoshitomo; Verzilov, Y.*; Wada, Masayuki*; Maekawa, Hiroshi

JAERI-Research 95-017, 71 Pages, 1995/03

JAERI-Research-95-017.pdf:3.09MB

no abstracts in English

Measurements and analyses of the ratio of U captures to U fission in low-enriched UO tight lattices

Nakajima, Ken; ; Yamamoto, Toshihiro; ; Suzaki, Takenori

Journal of Nuclear Science and Technology, 31(11), p.1160 - 1170, 1994/11

https://doi.org/10.3327/jnst.31.1160

no abstracts in English

Plate-out distribution of iodine in a high temperature gas cooling in-pile loop facility

Matsumoto, Mikio; Endo, Yasuichi; ; Itabashi, Yukio; ; Yokouchi, Iichiro; Ando, Hiroei

JAERI-M 92-212, 62 Pages, 1993/01

JAERI-M-92-212.pdf:2.09MB

no abstracts in English