Study on transient characteristics for bypass valve regulation and load rejection of microreactor with helium Brayton cycle

IF 3.3 3区工程技术 Q1 NUCLEAR SCIENCE & TECHNOLOGY

Progress in Nuclear Energy Pub Date : 2024-11-20 DOI:10.1016/j.pnucene.2024.105527

Xuyao Geng, Wenkui Ma, Jie Wang

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引用次数: 0

Abstract

Microreactors coupled with closed helium Brayton cycle (MR-CBC) can be used as mobile nuclear power source and have a wide range of application prospects. The power regulation methods and accident control measures are the key to safe and efficient operation of MR-CBC system. In this paper, the dynamic model of MR-CBC system is established, the characteristics of MR-CBC under bypass valve regulation method and load rejection event are analyzed. The results indicate that bypass valve is a fast regulating device. The power distribution of MR-CBC can be changed significantly and quickly with little change in core power. This regulation method changes the flow rate and operating performance of compressor and turbine, resulting in an increase in the proportion of compressor power consumption, a rapid reduction in generator power, and a significant drop in system efficiency. After losing the generator load, if no protection measures are taken, the shaft speed will increase rapidly and exceed the designed limit value in a short time. Due to the short time left for the protection system to act, it is necessary to prepare responsive control methods, such as bypass valve regulation. Finally, the transient characteristics of load rejection under the control of bypass valve are analyzed. Opening the bypass valve can avoid overspeed of the shaft. When the valve opening action is assumed to be completed in 0.25s, at least 1.37 kg/s of bypass flow rate is required to keep the rotational speed below designed limit value. The simulation results demonstrate the basic characteristics of power regulation and mitigation measures, and provide a reference for the design and operation of MR-CBC.

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氦气布雷顿循环微反应器旁通阀调节和负载抑制瞬态特性研究

微反应器耦合闭式氦-布雷顿循环（MR-CBC）可用作移动核动力源，具有广泛的应用前景。功率调节方法和事故控制措施是 MR-CBC 系统安全高效运行的关键。本文建立了 MR-CBC 系统的动态模型，分析了旁路阀调节方式和负载抑制事件下 MR-CBC 的特性。结果表明，旁通阀是一种快速调节装置。在核心功率变化很小的情况下，MR-CBC 的功率分布可以发生显著而快速的变化。这种调节方式改变了压缩机和汽轮机的流量和运行性能，导致压缩机功耗比例增加，发电机功率迅速降低，系统效率显著下降。失去发电机负荷后，如果不采取任何保护措施，轴转速会迅速上升，并在短时间内超过设计极限值。由于留给保护系统动作的时间很短，因此有必要准备响应性控制方法，如旁路阀调节。最后，分析了旁通阀控制下负载抑制的瞬态特性。打开旁通阀可以避免轴超速。假设阀门开启动作在 0.25s 内完成，则至少需要 1.37 kg/s 的旁通流量才能使转速保持在设计极限值以下。仿真结果表明了功率调节的基本特征和缓解措施，为 MR-CBC 的设计和运行提供了参考。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Progress in Nuclear Energy 工程技术-核科学技术

CiteScore

5.30

自引率

14.80%

发文量

331

审稿时长

3.5 months

期刊介绍： Progress in Nuclear Energy is an international review journal covering all aspects of nuclear science and engineering. In keeping with the maturity of nuclear power, articles on safety, siting and environmental problems are encouraged, as are those associated with economics and fuel management. However, basic physics and engineering will remain an important aspect of the editorial policy. Articles published are either of a review nature or present new material in more depth. They are aimed at researchers and technically-oriented managers working in the nuclear energy field. Please note the following: 1) PNE seeks high quality research papers which are medium to long in length. Short research papers should be submitted to the journal Annals in Nuclear Energy. 2) PNE reserves the right to reject papers which are based solely on routine application of computer codes used to produce reactor designs or explain existing reactor phenomena. Such papers, although worthy, are best left as laboratory reports whereas Progress in Nuclear Energy seeks papers of originality, which are archival in nature, in the fields of mathematical and experimental nuclear technology, including fission, fusion (blanket physics, radiation damage), safety, materials aspects, economics, etc. 3) Review papers, which may occasionally be invited, are particularly sought by the journal in these fields.