The thorny question of critical heat flux in plate-type reactors: A coherent methodology for the PALLAS-reactor

IF 1.9 3区工程技术 Q1 NUCLEAR SCIENCE & TECHNOLOGY

Nuclear Engineering and Design Pub Date : 2025-04-30 DOI:10.1016/j.nucengdes.2025.114075

F. Bertocchi , C.A. Vega

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引用次数: 0

Abstract

The PALLAS-reactor is an advanced, plate-type nuclear reactor designed for producing medical isotopes currently under construction in the Netherlands. Adequately estimating the critical heat flux (CHF) for all postulated accident scenarios is crucial for licensing the reactor, for which the Reactor Excursion and Leak Analysis Program (RELAP5/MOD3.3 Patch 5) program is the primary licensing code. Literature has shown that the look-up tables (LUT) of RELAP over-predict the CHF with forced convection through narrow rectangular channel, thus highlighting the need for alternative tools better suited to this geometry. These tools have been identified in ancillary publications complementary to the present one. However, a methodology is still missing that provides guidance to the analyst for estimating the CHF in all postulated accident conditions. Therefore, this publication aims at providing a first coherent approach to estimate the CHF in the rectangular channels of a plate-type nuclear reactor, by illustrating the case study of the PALLAS-reactor. Of the available CHF correlations, we have selected the Sudo-Kaminaga correlation modified by Kim (SK-Kim) for estimating the CHF in forced convection. For natural circulation, the CHF is estimated through the 2006 LUT of RELAP5/MOD3.3 Patch 5 since these are applicable to narrow channels when buoyancy is dominant. Discriminating between forced and natural convection regimes relies on the value of a dimensionless group derived from representative experiments. If the SK-Kim correlation predicts that the CHF limit is approached in one of the cooling channels, this is to be modeled by a validated computational fluid dynamics (CFD) tool in order to more accurately account for the effects of fast transients. This work provides the first, well-founded and coherent methodology for estimating the CHF in a plate-type nuclear reactor. In this respect, it represents a cornerstone of the PALLAS-reactor licensing process that, just as importantly, can support the safety analyses of other reactors of similar design.

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板型反应堆临界热通量的棘手问题：pallas反应堆的连贯方法

pallas反应堆是一种先进的板式核反应堆，设计用于生产医用同位素，目前正在荷兰建造。充分估计所有假定事故情景的临界热通量（CHF）对于反应堆许可至关重要，其中反应堆偏移和泄漏分析程序（RELAP5/MOD3.3 Patch 5）程序是主要许可代码。文献表明，RELAP的查找表（LUT）过度预测了通过窄矩形通道强制对流的CHF，从而突出了对更适合这种几何形状的替代工具的需求。这些工具已在补充本报告的辅助出版物中确定。然而，仍然缺少一种方法，为分析人员在所有假定的事故条件下估计CHF提供指导。因此，本出版物旨在通过说明pallas反应堆的案例研究，提供第一个连贯的方法来估计板式核反应堆矩形通道中的CHF。在现有的CHF相关中，我们选择了经Kim （SK-Kim）修正的Sudo-Kaminaga相关来估计强迫对流中的CHF。对于自然环流，CHF是通过RELAP5/MOD3.3 Patch 5的2006年LUT来估计的，因为这些适用于浮力占主导地位的狭窄通道。强迫对流和自然对流的区分依赖于从代表性实验中得出的无量纲群的值。如果SK-Kim相关性预测在一个冷却通道中接近CHF极限，则应通过经过验证的计算流体动力学（CFD）工具对其进行建模，以便更准确地解释快速瞬变的影响。这项工作提供了第一个，有充分根据和连贯的方法来估计板式核反应堆的CHF。在这方面，它代表了pallas反应堆许可程序的基石，同样重要的是，它可以支持对其他类似设计的反应堆进行安全分析。

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

Nuclear Engineering and Design 工程技术-核科学技术

CiteScore

3.40

自引率

11.80%

发文量

377

审稿时长

5 months

期刊介绍： Nuclear Engineering and Design covers the wide range of disciplines involved in the engineering, design, safety and construction of nuclear fission reactors. The Editors welcome papers both on applied and innovative aspects and developments in nuclear science and technology. Fundamentals of Reactor Design include: • Thermal-Hydraulics and Core Physics • Safety Analysis, Risk Assessment (PSA) • Structural and Mechanical Engineering • Materials Science • Fuel Behavior and Design • Structural Plant Design • Engineering of Reactor Components • Experiments Aspects beyond fundamentals of Reactor Design covered: • Accident Mitigation Measures • Reactor Control Systems • Licensing Issues • Safeguard Engineering • Economy of Plants • Reprocessing / Waste Disposal • Applications of Nuclear Energy • Maintenance • Decommissioning Papers on new reactor ideas and developments (Generation IV reactors) such as inherently safe modular HTRs, High Performance LWRs/HWRs and LMFBs/GFR will be considered; Actinide Burners, Accelerator Driven Systems, Energy Amplifiers and other special designs of power and research reactors and their applications are also encouraged.