3-D numerical studies of single control rod withdrawal transients in an LBE cooled critical reactor

IF 2.1 3区工程技术 Q1 NUCLEAR SCIENCE & TECHNOLOGY

Nuclear Engineering and Design Pub Date : 2025-08-30 DOI:10.1016/j.nucengdes.2025.114419

Xue-Nong Chen , Yoshiharu Tobita , Andrei Rineiski , Barbara Kędzierska , Guy Scheveneels , Matteo Zanetti , Bogdan Yamaji

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Abstract

The presented studies are carried out within the EU project ANSELMUS. A recent design version of MYRRHA (Multi-purpose hYbrid Research Reactor for High-tech Applications), which is a Lead-Bismuth-Eutectic (LBE) cooled reactor developed at SCK-CEN (Belgian Nuclear Research Centre), is investigated. The SIMMER-IV code is employed for 3-D simulations of single control rod withdrawal (CRWD) transients at the critical operation mode. A new CRWD model for the SIMMER-IV code is developed, so that the CRWD can be simulated for any constant withdrawal speed and from any initial position. The basic case is the complete withdrawal of a control rod (CR) filled with B4C absorber with the natural boron, where the reactivity worth is about 0.9 $, from a fully inserted position within 3 s. Cases with and without scram after 3 s are considered. The spatial kinetics effects on the power distribution are evaluated by comparing relative variations in time of local power densities and of the total one. The dynamic reactivity values during CRWD have been confirmed to be close to those obtained by static calculations. The transient with the scram at 3 s results in nothing severe, but that without the scram leads to local fuel melting. A further example, where the CR is filled with an enriched by B-10 absorber, its reactivity worth being 1.7 $, is calculated and shown as well. The withdrawal leads to a severe accident with fuel pin degradation, but without prompt supercritical power excursion. The numerical scenarios are presented and investigated by means of parametric studies.

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LBE冷却临界反应堆单控制棒抽离瞬态的三维数值研究

所提出的研究是在欧盟ANSELMUS项目内进行的。研究了比利时核研究中心（SCK-CEN）开发的铅-铋-共晶（LBE）冷却反应堆MYRRHA（高科技应用多用途混合研究反应堆）的最新设计版本。采用SIMMER-IV程序对临界工况下的单控制棒抽离瞬态进行了三维仿真。为SIMMER-IV代码开发了一种新的CRWD模型，以便可以在任何恒定的提取速度和任何初始位置模拟CRWD。基本情况是，在3秒内，从完全插入的位置完全撤出充满天然硼的B4C吸收剂的控制棒（CR），其反应性值约为0.9美元。在3秒后考虑有和没有紧急情况。通过比较局部功率密度和总功率密度在时间上的相对变化来评价空间动力学对功率分布的影响。经证实，CRWD过程中的动态反应性值与静态计算结果接近。在30s紧急启动的瞬态不会造成严重后果，但不紧急启动的瞬态会导致局部燃料熔化。再举一个例子，用B-10吸收剂富集的CR填充，其反应性为1.7美元。退出会导致燃料销退化的严重事故，但不会引起超临界功率偏移。通过参数化研究，给出了数值模拟结果。

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.