JOPSS - Search Results

Journal Articles

Compact and transportable system for detecting lead-shielded highly enriched uranium using $^{252}$ Cf rotation method with a water Cherenkov neutron detector

Tanabe, Kosuke*; Komeda, Masao; Toh, Yosuke; Kitamura, Yasunori*; Misawa, Tsuyoshi*; Tsuchiya, Kenichi*; Sagara, Hiroshi*

Scientific Reports (Internet), 14, p.18828_1 - 18828_10, 2024/08

https://doi.org/10.1038/s41598-024-69526-w

Times Cited Count：0 Percentile：0.00(Multidisciplinary Sciences)

Journal Articles

Systematic measurements and analyses for lead void reactivity worth in a plutonium core and two uranium cores with different enrichments

Fukushima, Masahiro; Goda, J.*; Oizumi, Akito; Bounds, J.*; Cutler, T.*; Grove, T.*; Hayes, D.*; Hutchinson, J.*; McKenzie, G.*; McSpaden, A.*; et al.

Nuclear Science and Engineering, 194(2), p.138 - 153, 2020/02

https://doi.org/10.1080/00295639.2019.1663089

Times Cited Count：7 Percentile：54.72(Nuclear Science & Technology)

To validate lead (Pb) nuclear cross sections, a series of integral experiments to measure lead void reactivity worth was conducted systematically in three fast spectra with different fuel compositions on the Comet critical assembly of the National Criticality Experiments Research Center. Previous experiments in a high-enriched uranium (HEU)/Pb and a low-enriched uranium (LEU)/Pb systems had been performed in 2016 and 2017, respectively. A follow-on experiment in a plutonium (Pu)/Pb system has been completed. The Pu/Pb system was constructed using lead plates and weapons grade plutonium plates that had been used in the Zero Power Physics Reactor (ZPPR) of Argonne National Laboratory until the 1990s. Furthermore, the HEU/Pb system was re-examined on the Comet critical assembly installed newly with a device that can guarantee the gap reproducibility with a higher accuracy and precision, and then the experimental data was re evaluated. Using the lead void reactivity worth measured in these three cores with different fuel compositions, the latest nuclear data libraries, JENDL 4.0 and ENDF/B VIII.0, were tested with the Monte Carlo calculation code MCNP version 6.1. As a result, the calculations by ENDF/B-VIII.0 were confirmed to agree with lead void reactivity worth measured in all the cores. It was furthermore found that the calculations by JENDL 4.0 overestimate by more than 20% for the Pu/Pb core while being in good agreements for the HEU/Pb and LEU/Pb cores.

Journal Articles

Reactivity effect measurement of neutron interaction between two slab cores containing 10% enriched uranyl nitrate solution without neutron isolater

Tonoike, Kotaro; Miyoshi, Yoshinori; Okubo, Kiyoshi

Journal of Nuclear Science and Technology, 40(4), p.238 - 245, 2003/04

https://doi.org/10.3327/jnst.40.238

Times Cited Count：2 Percentile：18.58(Nuclear Science & Technology)

The reactivity effect of neutron interaction between two identical units containing low enriched (10% $^{235}$ enrichment) uranyl nitrate solution was measured in the STACY. The unit has 350mm of thickness and 690mm of width and distance between those two units was adjustable from 0mm to 1450mm. Condition of the solution was about 290gU/L in uranium concentration, about 0.8N in free nitric acid molarity, 2427 $^{circ}$ C in temperature and about 1.4g/cm $^{3}$ in solution density. The reactivity effect was estimated from variation of critical solution level from 495mm to 763mm depending on the core distance. The reactivity effect was also evaluated by the solid angle method and a computational method using the continuous energy Monte Carlo code MCNP-4C and the nuclear data library JENDL3.2. Comparison of those estimations is presented.

Journal Articles

Critical experiments on 10% enriched uranyl nitrate solution using an 80-cm-diameter cylindrical core

Yamane, Yuichi; Miyoshi, Yoshinori; Watanabe, Shoichi; Yamamoto, Toshihiro

Nuclear Technology, 141(3), p.221 - 232, 2003/03

https://doi.org/10.13182/NT03-A3363

Times Cited Count：6 Percentile：40.97(Nuclear Science & Technology)

no abstracts in English

JAEA Reports

Thermal hydraulic analysis of the JMTR improved LEU-core

Tabata, Toshio; Nagao, Yoshiharu; Komukai, Bunsaku; Naka, Michihiro; Takeda, Takashi*; Fujiki, Kazuo

JAERI-Tech 2002-100, 108 Pages, 2003/01

JAERI-Tech-2002-100.pdf:4.44MB

After the investigation of the new core arrangement for the JMTR reactor in order to enhance the fuel burn-up and consequently extend the operation period, the "improved LEU core" that utilized 2 additional fuel elements instead of formerly installed reflector elements, was adopted. This report describes the results of the thermal-hydraulic analysis of the improved LEU core as a part of safety analysis for the licensing. The analysis covers steady state, abnormal operational transients and accidents, which were described in the annexes of the licensing documents as design bases events. Calculation conditions for the computer codes were conservatively determined based on the neutronic analysis results and others. The results of the analysis, that revealed the safety criteria were satisfied on the fuel temperature, DNBR and primary coolant temperature, were used in the licensing. The operation license of the JMTR with the improved LEU core was granted in March 2001, and the reactor operation with new core started in November 2001 as 142nd operation cycle.

Journal Articles

Kinetic parameter $beta_{rm eff}/ell$ measurement on low enriched uranyl nitrate solution with single unit cores (600, 280T, 800) of STACY

Tonoike, Kotaro; Miyoshi, Yoshinori; Kikuchi, Tsukasa*; Yamamoto, Toshihiro

Journal of Nuclear Science and Technology, 39(11), p.1227 - 1236, 2002/11

https://doi.org/10.3327/jnst.39.1227

Times Cited Count：21 Percentile：76.73(Nuclear Science & Technology)

Kinetic parameter $beta_{rm eff}/ell$ of low enriched uranyl nitrate solution was measured by the pulsed neutron source method in the STACY. This measurement was repeated systematically over several uranium concentrations from 193.7 gU/ to 432.1 gU/. Used core tanks were two cylindrical tanks whose diameters are 600 mm and 800 mm and one slab tank which has 280 mm thickness and 700 mm width. In this report, experimental data such as solution conditions, critical solution level for each solution condition, subcritical solution levels where measurements were conducted, measured decay time constants of prompt neutron and extrapolated $beta_{rm eff}/ell$ values are described as well as basic principle of the pulsed neutron source method. $beta_{rm eff}/ell$ values were evaluated also by computation with the diffusion code CITATION in SRAC and the nuclear data library JENDL 3.2. Both experimental and computational $beta_{rm eff}/ell$ values show good agreement.