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

Taninaka, Hiroshi; Hashimoto, Kazuo; Pyeon, Cheol Ho; Sano, Tadafumi; Misawa, Tsuyoshi; Unesaki, Hironobu; Sugiyama, Wataru; Ohsawa, Takaaki

doi:10.1080/18811248.2011.9711772

Cited by 18 publications

(3 citation statements)

References 34 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…A series of accelerator-beam trip and restart experiments is carried out to determine the subcriticality of a reactor system driven by a pulsed 14 MeV neutron source [28]. This core configuration is shown in Fig.…”

Section: Core Configurationsmentioning

confidence: 99%

Subcriticality

Hashimoto

2021

Accelerator-Driven System at Kyoto University Critical Assembly

Self Cite

View full text Add to dashboard Cite

For a subcritical reactor system driven by a periodically pulsed spallation neutron source in KUCA, the Feynman-α and the Rossi-α neutron correlation analyses are conducted to determine the prompt neutron decay constant and quantitatively to confirm a non-Poisson character of the neutron source. The decay constant determined from the present Feynman-α analysis well agrees with that from a previous analysis for the same subcritical system driven by an inherent source. Considering the effect of a higher mode excited, the disagreement can be successfully resolved. The power spectral analysis on frequency domain is also carried out. Not only the cross-power but also the auto-power spectral density have a considerable correlated component even at a deeply subcritical state, where no correlated component could be previously observed under a 14 MeV neutron source. The indicator of the non-Poisson character of the present spallation source can be obtained from the spectral analysis and is consistent with that from the Rossi-α analysis. An experimental technique based on an accelerator-beam trip or restart operation is proposed to determine the subcritical reactivity of 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.

show abstract

Section: Core Configurationsmentioning

confidence: 99%

Subcriticality

Hashimoto

2021

Accelerator-Driven System at Kyoto University Critical Assembly

Self Cite

View full text Add to dashboard Cite

show abstract

“…Several fuel and reflector assemblies assigned as the central fuel loading is downward withdrawn to shut down urgently the reactor operation. To the central fuel loading withdrawn by the emergency system, we assigned three fuel assemblies on positions (I,14)-(I,16) and six polyethylene-reflector assemblies on positions (G,14)-(G, 16) and (H,14)-(H, 16) of the grid matrix shown in Figure 1. The subcritical reactivity for the present experiment was adjusted by changing the axial position of the central fuel loading, as well as the positions of safety and control rods.…”

Section: Description Of Kuca Facilitymentioning

confidence: 99%

“…A wide variety of reactor physics experiments on an ADS using the pulsed spallation neutrons is now in progress [10,11]. In the preparation for connecting the proton-beam accelerator at KUCA, a series of static and kinetic experiments on an ADS with pulsed 14 MeV neutrons has been conducted [12][13][14][15][16][17][18][19][20]. As a basic study for online monitoring of the subcriticality in the operation of an ADS, various Feynman-α and power spectral analyses for a subcritical reactor system driven by a pulsed 14 MeV neutron source have been performed.…”

Section: Introductionmentioning

confidence: 99%

Determination of prompt-neutron decay constant from phase shift between beam current and neutron detection signals for an accelerator-driven system in the Kyoto University Critical Assembly

Sakon

Hashimoto

Sugiyama

et al. 2014

Journal of Nuclear Science and Technology

Self Cite

View full text Add to dashboard Cite

A unique power spectral analysis for a subcritical reactor system driven by a pulsed 14 MeV neutron source was carried out at the Kyoto University Critical Assembly (KUCA). In this analysis, a complex cross-power spectral density between time-sequence signal data from an accelerator beam ammeter and a neutron detector was measured to determine the prompt-neutron decay constant of an accelerator-driven system (ADS) from the phase data of the spectral density. Assuming the one-point kinetics model, in theory, the decay constant can be arithmetically derived from the phase at the integral multiples of the pulse repetition frequency. However, the actual derivation from the phase at a pulse repetition frequency of 20 Hz considerably underestimated the prompt-neutron decay constant, compared with that obtained by a previous pulsed neutron experiment, and the derived decay constant apparently decreased with an increase in the multiple of the pulsed repetition frequency. Considering a lag time in detector response, the above underestimation and the above apparent decrease were solved to obtain the consistent decay constant. While both previous power spectral analysis and Feynman-α analysis for pulsed neutron source require non-linear least-squares fits of the respective complicated formulae, the present analysis makes the fitting unnecessary except at regular calibration of the lag time. This feature is advantageous for a robust online monitoring of subcritical reactivity of an actual ADS.

show abstract

Introduction

Pyeon

2021

Accelerator-Driven System at Kyoto University Critical Assembly

Self Cite

View full text Add to dashboard Cite

At the Kyoto University Critical Assembly (KUCA), the accelerator-driven system (ADS) is composed of a solid-moderated and solid-reflected core (A-core) and a pulsed-neutron generator (14 MeV neutrons) or the fixed-filed alternating gradient (FFAG) accelerator (100 MeV protons). At KUCA, two external neutron sources, including 14 MeV neutrons and 100 MeV protons, are separately injected into the A-core, and employed for carrying out the ADS experiments. With the combined use of the A-core and two external neutron sources, basic and feasibility studies of ADS have been engaged in the examination of neutronics of ADS, through the measurements of statics and kinetics parameters of reactor physics, including subcritical multiplication factor, subcriticality, prompt neutron decay constant, effective delayed neutron fraction, neutron spectrum, and reaction rates.

show abstract

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

Cited by 18 publications

References 34 publications

Subcriticality

Subcriticality

Determination of prompt-neutron decay constant from phase shift between beam current and neutron detection signals for an accelerator-driven system in the Kyoto University Critical Assembly

Introduction

Contact Info

Product

Resources

About