| Project/Area Number |
08680528
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
エネルギー学一般・原子力学
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| Research Institution | KYUSHU UNIVERSITY |
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Principal Investigator |
RAO Yanfei Kyushu University, Department of Nuclear Engineering Associate Professor, 工学部, 助教授 (10243891)
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| Co-Investigator(Kenkyū-buntansha) |
FUKUDA Kenji Kyushu University Department of Nuclear Engineering Professor, 工学部, 教授 (90117234)
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| Project Period (FY) |
1996 – 1997
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| Project Status |
Completed (Fiscal Year 1997)
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| Budget Amount *help |
¥2,000,000 (Direct Cost: ¥2,000,000)
Fiscal Year 1997: ¥900,000 (Direct Cost: ¥900,000)
Fiscal Year 1996: ¥1,100,000 (Direct Cost: ¥1,100,000)
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| Keywords | BWR / Thermal-Neutronic Coupling / Two-Phase Flow / Flow Instability / Linear Analysis / Experimental Simulator / Void-Reactivity / Regional Instability / 実験シシューレーター / 実験シミュレーター |
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| Research Abstract |
In order to study the coupled neutronic and thermal-hydraulic instabilities of two-phase flows in Boiling Water Reactors, frequency-domain analytical models were developed for both the core-wide and the regional instabilities. An experimental simulator was designed in which the heating power in a real boiling two-phase flow channel was computer-controlled according to measured void-fraction rates in the channel to simulate the void-reactivity feedback. In the two-year period of 1996-1998 the fo11owing results were obtained.
(1) Experiments were conducted with the experimental simulator using a single boiling channel for the case of the core-wide instability, the results were compared to analytical ones, and the usefulness of the experimental simulator was confirmed.
(2) To study the regional instability, a simple analytical model called the "Subcore Model" was developed, in which the channel-to-channel (or the subcore-to-subcore) interaction was coped with through introduction of a coefficient that relates the void-reactivity in one channel with void-fraction in another. From the results with this model, it was found that the flow in a subcore tends to oscillates in-phase with a subcore to which it has stronger interaction and out-of-phase with a subcore to which it has weaker interaction.
(3) A more advanced analytical model called the "Multi-Point-Reactor Model" was developed, in which the subcore-to-subcore interaction was directly modeled by modifying the subcore neutron dynamics equation that including the effect of the neutron diffusion to and from the other subcores. Analytical results with the model confirmed basic findings obtained with the Subcore Model about the effect of subcore-to-subcore interaction on the flow oscillation patterns.
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