Neutron Generation Time in Highly-Enriched Uranium Core at Kyoto University Critical Assembly

Pyeon, Cheol Ho; Yamanaka, Masao; Endo, Takao; Chiba, Go; Rooijen, W.F.G. van; Watanabe, K.

doi:10.1080/00295639.2020.1774230

Cited by 4 publications

(3 citation statements)

References 24 publications

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“…In the two critical cores [23] shown in Figs. A4.1 and A4.4, criticality was reached at positions of control (C1, C2, and C3) and safety (S4, S5, and S6) rods for the total number of HEU fuel plates: 3016 and 3008, as shown in Tables 4.14 and 4.15, respec- tively.…”

Section: Methodsmentioning

confidence: 99%

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Effective Delayed Neutron Fraction

Yamanaka

2021

Accelerator-Driven System at Kyoto University Critical Assembly

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In kinetic analyses on ADS, although adjoint flux distribution is defined under the existence of an external neutron source, an issue of the proper determination of the weighting function still remains in the definition to obtain the kinetics parameters in the fixed-source calculations. Here, an alternative methodology is proposed with the combined use of the k-ratio method and the reaction rates obtained by the fixed-source calculations, when the subcriticality level or the spectrum of the external neutron source is varied. In ADS experiments, the measurement of βeff is expected to provide complementary verification of the calculation and reliability of nuclear data. Then, the formulation of the Rossi-α method in the pulsed-neutron source has been already available for application to the subcriticality measurement in the pulsed-neutron source (PNS) experiments. Accordingly, the methodology is applied uniquely to deduce the βeff value with the pulsed-neutron source (spallation neutrons), with the combined use of the results of experiments and calculations. Using parameters α and ρ$, the values of βeff/Λ are deduced at near-critical configurations through experimental analyses. To estimate the numerical precision of Λ, the value of βeff/Λ is used as an index of Λ evaluation that is defined by a ratio of Λ values in the super-critical and subcritical states.

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Section: Methodsmentioning

confidence: 99%

“…A4.1) was about 880, 150, and 520 pcm, respectively. In the ADS core (3000 HEU fuel plates) at the subcritical state [23], deuteron beams were injected onto a tritium target set at (14-15, X) in Fig. A4.3a.…”

Section: Methodsmentioning

confidence: 99%

Effective Delayed Neutron Fraction

Yamanaka

2021

Accelerator-Driven System at Kyoto University Critical Assembly

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“…To address the issue of excessive detector requirements in the traditional DMD-Rossialpha method, this study optimizes the DMD-Rossi-alpha method using the efficient and precise LHS method. This research focuses on the Kyoto University Critical Assembly (KUCA), utilizing RMC3.5 simulations to validate the accuracy and applicability of the proposed LHS-DMD-Rossi-alpha method across different subcritical states [6][7][8][9].…”

Section: Introductionmentioning

confidence: 99%

Research on the Measurement Method of the Prompt Neutron Decay Constant Based on LHS-DMD-Rossi-Alpha

Li,

Xie,

Deng

et al. 2024

Energies

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In response to the significant dependency on empirical judgment in measuring the prompt neutron decay constant with the traditional Rossi-alpha method and the issue of requiring an excessive number of detectors with the DMD-Rossi-alpha method, this paper introduces a calculation method for the prompt neutron decay constant based on a combination of Latin Hypercube Sampling (LHS), Dynamic Mode Decomposition (DMD), and the Rossi-alpha method. Initially, the method uses LHS to expand the sample dataset of neutron noise data to reduce the number of detectors required. It then employs the Rossi-alpha method to construct a Rossi-alpha distribution model from neutron noise data. Finally, it utilizes DMD for feature extraction from the Rossi-alpha distribution model, thereby determining the prompt neutron decay constant. Research findings demonstrate that, by simulating the KUCA facility using RMC3.5 in a near-critical state, the relative error of the α value calculated by the LHS-DMD-Rossi-alpha method model is 9% less than that calculated by the Rossi-alpha method. This approach, capable of enhancing the precision of measuring the prompt neutron decay constant with just a single detector, holds significant theoretical value and engineering significance for the advancement of reactor physics and experimental techniques.

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Introduction

Pyeon

2021

Accelerator-Driven System at Kyoto University Critical Assembly

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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.

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Neutron Generation Time in Highly-Enriched Uranium Core at Kyoto University Critical Assembly

Cited by 4 publications

References 24 publications

Effective Delayed Neutron Fraction

Effective Delayed Neutron Fraction

Research on the Measurement Method of the Prompt Neutron Decay Constant Based on LHS-DMD-Rossi-Alpha

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