Benchmark critical experiments and FP worth evaluation for a heterogeneous system of uranium fuel rods and pseudo FP doped uranium solution

Tonoike, Kotaro; Miyoshi, Yoshinori; Uchiyama, Gunzo; Watanabe, Shoichi*; Yamamoto, Toshihiro*

Proceedings of 8th International Conference on Nuclear Criticality Safety (ICNC 2007), p.222 - 227, 2007/05

In order to obtain systematic benchmark criticality data concerning dissolving process in a reprocessing plant for LWR spent fuel, a series of critical experiments were performed using heterogeneous cores at the Static Experiment Critical Facility (STACY) in Japan Atomic Energy Agency (JAEA). Focusing on the introduction of the burn-up credit to the process, critical mass measurement was conducted for a combination of uranium fuel rods and uranium solution where pseudo fission product (FP) materials were doped. In this report, the "pseudo FP materials" means elements such as Sm, Cs, Rh and Eu whose isotopic composition is natural but which contains some FP nuclide(s). The result is going to provide basic experimental data for validation of computational methods to evaluate a reactivity effect of each FP material, as well as benchmark criticality data for validation of neutron multiplication factor calculation of heterogeneous systems of spent fuel. In the report, detail of the experiments including a differential reactivity worth curve over the solution level variation is going to be provided as well as the procedure and the result of separate reactivity worth evaluation of each pseudo FP material. Comparison of the experimental result and the computational evaluation will also be presented.

Measurement of temperature effect on low enrichment STACY heterogeneous core

Watanabe, Shoichi; Yamamoto, Toshihiro; Miyoshi, Yoshinori

Transactions of the American Nuclear Society, 91, p.431 - 432, 2004/11

Temperature effect is a main factor which affects the transient characteristics at a criticality accident. A series of reactivity effects due to changes in fuel temperatures were measured for two kinds of STACY heterogeneous lattice configurations. The core was composed of LWR-type fuel rod array and low-enriched uranyl-nitrate-solution concerning the dissolver of the reprocessing facility for LWR spent fuel. The critical solution heights at various solution temperatures were measured. From the change of the critical water height with fuel temperature, the reactivity effect was evaluated by a critical-solution-level worth method. The temperature effect was also calculated by using SRAC and the transport calculation code TWODANT. The experimental value was estimated to be -2.0 cent/C for the case "2.1cm-pitch", and -2.5 cent/C for the case "1.5cm-pitch". The calculated results gave agreement with the experiments within 10%.

Development of a kinetics analysis code for fuel solution combined with thermal-hydraulics analysis code PHOENICS and analysis of natural-cooling characteristic test of TRACY (Contract research)

Watanabe, Shoichi; Yamane, Yuichi; Miyoshi, Yoshinori

JAERI-Tech 2003-045, 73 Pages, 2003/03

JAERI-Tech-2003-045.pdf:4.96MB

Since exact information is not always acquired in the criticality accident of fuel-solution, parametric survey calculations are required for grasping behaviors of the thermal-hydraulics. On the other hand, the practical methods of the calculation which can reduce the computation time with allowable accuracy will be also required, since the conventional method takes a long calculation time. In order to fulfill the requirement, a three-dimensional nuclear-kinetics analysis code considering thermal-hydraulic based on the multi-region kinetic equations with one-group neutron energy was created by incorporating the thermal-hydraulics analysis code PHOENICS as a subroutine. The computation time of the code was shortened by separating time mesh intervals of the nuclear- and heat-calculations from that of the hydraulics calculation, and by regulating automatically the time mesh intervals in proportion to power change rate. A series of analysis were performed for the natural-cooling characteristic test using TRACY in which the power changed slowly for 5 hours after the transient power resulting from the reactivity insertion of a 0.5 dollar. It was found that the code system was able to calculate within the limit of practical time, and acquired the prospect of reproducing the experimental values considerably for the power and temperature change.

Criticality safety benchmark experiment on 10% enriched uranyl nitrate solution using a 28-cm-thickness slab core

Yamamoto, Toshihiro; Miyoshi, Yoshinori; Kikuchi, Tsukasa*; Watanabe, Shoichi

Journal of Nuclear Science and Technology, 39(7), p.789 - 799, 2002/07

https://doi.org/10.3327/jnst.39.789

no abstracts in English

VXIbus-based signal generator for resonant power supply system of the 3GeV RCS

Zhang, F.; Watanabe, Yasuhiro; Koseki, Shoichiro*; Tani, Norio; Adachi, Toshikazu*; Someya, Hirohiko*

JAERI-Tech 2002-039, 21 Pages, 2002/03

JAERI-Tech-2002-039.pdf:2.2MB

The 3 GeV Proton RCS of the JAERI-KEK Joint Project is a 25 Hz separate-function rapid cycling synchrotron under design. Bending magnets (BM) and quadrupole magnets (QM) are excited separately. The 3 GeV RCS requests above 10 families of magnets excited independently, far beyond 3 families in practical RCS's. Difficulty of field tracking between BM and QM is significantly increased Magnet strings are grouped into resonant networks and excited resonantly by power supplies driven by a waveform pattern, typically a DC-biased sinusoidal signal. To achieve a close tracking between many families, the driving signal of each power supply should be adjusted in phase and amplitude flexibly and dynamically.This report proposes a signal generator based on VXIbus. The VXIbus, an extension of VMEbus (VME eXtension for Instrument), provides an open architecture with shared process bus and timing. The VXIbus-based signal generator facilitates the timing synchronization and extension to many channels needed by the 3 GeV RCS. Experimental results of the signal generator are reported.

Study of resonant magnet exciting system for the 3GeV proton synchrotron

Koseki, Shoichiro*; Zhang, F.; Watanabe, Yasuhiro; Tani, Norio; Adachi, Toshikazu*; Someya, Hirohiko*

Heisei-13-Nen Denki Gakkai Sangyo Oyo Bumon Zenkoku Taikai Koen Rombunshu, 1, p.253 - 256, 2001/08

no abstracts in English

A Solution pouring test of JCO precipitation tank using a visualization vessel

Watanabe, Shoichi; Miyoshi, Yoshinori

JAERI-Data/Code 2001-008, 62 Pages, 2001/03

JAERI-Data-Code-2001-008.pdf:17.38MB

no abstracts in English