Static and Kinetic Experiments on Accelerator-Driven System with 14 MeV Neutrons in Kyoto University Critical Assembly

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An experimental technique based on an accelerator-beam trip or restart operation is proposed to determine the subcritical reactivity of an accelerator-driven system (ADS). Applying the least-squares inverse kinetics method to the data analysis, the subcriticality can be inferred from time-sequence neutron count data after these operations. A series of beam trip and restart experiments with 14 MeV neutrons were carried out in a thermal ADS of Kyoto University Critical Assembly (KUCA), to demonstrate the applicability of the proposed technique. The subcriticalities evaluated using neutron counters far from the DT target were consistent with those obtained in a previous pulsed neutron experiment. However, a counter placed close to the target significantly overestimated the subcriticality. The present technique is expected to be available for subcriritcality measurement at startup and shutdown of various ADSs.

Section: Reactor Configuration and Experimental Setups 1 Descripmentioning

confidence: 99%

Determination of Subcritical Reactivity of a Thermal Accelerator-Driven System from Beam Trip and Restart Experiment

Taninaka

Hashimoto

Pyeon

et al. 2011

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“…Adjacent to both the axial sides of the active region of each fuel assembly, about 60-cm-long upper and lower polyethylene reflectors were attached. The configuration of these fuel assemblies is reported in detail by Pyeon et al [25].…”

Section: Description Of Kuca Facilitymentioning

confidence: 99%

“…In the preparation for connecting the proton-beam accelerator at KUCA, a series of static and kinetic experiments [25][26][27][28][29][30] on ADS with 14 MeV neutrons have been conducted. These experiments have been carried out in several solid-moderated and -reflected cores.…”

Section: Description Of Kuca Facilitymentioning

confidence: 99%

Power spectral analysis for a thermal subcritical reactor system driven by a pulsed 14 MeV neutron source

Sakon

Hashimoto

Sugiyama

et al. 2013

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A series of power spectral analyses for a thermal subcritical reactor system driven by a pulsed 14 MeV neutron source was carried out at Kyoto University Critical Assembly (KUCA), to determine the promptneutron decay constant of the accelerator-driven system (ADS). The cross-power spectral density between time-sequence signal data of two neutron detectors was composed of a familiar continuous reactor noise component and many delta-function-like peaks at the integral multiple of pulse repetition frequency. The prompt-neutron decay constant inferred from the reactor noise component of the cross-power spectral density was consistent with that obtained by a pulsed neutron experiment. However, the reactor noise component of the auto-power spectral density of each detector was hidden by a white chamber noise in the higher-frequency range and this feature resulted in a considerable underestimation of the decay constant. For several runs with a low pulse-repetition frequency, furthermore, we attempted to infer the decay constant from point data of the delta-function-like peaks. The analysis for a run under a slightly subcritical state resulted in the consistent decay constant; however, those for other runs under significantly subcritical states underestimated the decay constant. Considering the contribution of a spatially higher mode to the point data, the above underestimation was solved to obtain the consistent decay constant. While the Feynman-α formula for a pulsed neutron source is too complicated to be fitted directly to variance-to-mean ratio data, the present analysis on frequency domain is much simpler and the conventional formula based on the first-order reactor transfer function is available for fitting to power spectral density data.

“…The Kyoto University Research Reactor Institute (KURRI) carried out a series of experiments [1][2][3][4][5] on the Accelerator-Driven System (ADS) with 14 MeV neutrons at the Kyoto University Critical Assembly (KUCA), for a future joint research plan with the Kumatori AcceleratorDriven Reactor Test Facility and Innovation Research Laboratory: Kart & Lab. Project.…”

Section: Introductionmentioning

confidence: 99%

Reaction Rate Analysis of Nuclear Spallation Reactions Generated by 150, 190, and 235MeV Protons

Pyeon

Shiga

Abe

et al. 2010

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At the National Cancer Center, proton irradiation experiments have been conducted using the cyclotron accelerator to measure the neutron spectrum by the foil activation method. The experimental results demonstrate that high-energy neutrons are bombarded by injecting high-energy protons onto the tungsten target. The agreement between the results of the experiments and the MCNPX calculations with ENDF/ B-VI is around 20% in the relative difference of the C/E (calculation/experiment) values in some of the 209 Bi(n, xn) 210Àx Bi reactions. Here, the activation foil 209 Bi is useful in obtaining experimental neutron spectrum information on nuclear spallation reactions of the tungsten target by the high-energy protons ranging between 150 and 235 MeV. The current experimental data could contribute to evaluating the accuracy of the numerical simulation methodology of reaction rates and the uncertainties of cross sections of 209 Bi, as experimental benchmarks.