Abstract Even for small modular reactors (SMRs) with all large pipes removed, a small-break loss-of-coolant accident (SBLOCA) is an important design-basis accident (DBA). Experimental simulation of the SBLOCA scenario is essential before a prototype reactor is realized. The system-integrated modular advanced reactor (SMART) is one of the SMRs developed by the Korea Atomic Energy Research Institute. An integral test loop, SMART-ITL, was also constructed to carry out several types of integral thermal-hydraulic effects tests for the prototype reactor. The SMART-ITL was designed with a preserved height, 1/7th diameter, and 1/49th area, and volume-scaling ratios. Two types of passive safety systems were equipped in the SMART-ITL: a passive safety injection system (PSIS) and a passive residual heat removal system (PRHRS). The PSIS was designed to refill the coolant in the reactor coolant system (RCS) for 72 h after an accident. Under accident conditions the PRHRS prevents overheating and overpressurization of the RCS using two-phase natural circulation. The SBLOCA on the passive safety injection line is a significant DBA that should be validated for differences in break size. In this paper, the effects of two different break sizes, 2 and 7/32 in., were analyzed in order to study the effect of the maximum and minimum mass and energy loss of the RCS. In order to simulate a clear difference between maximum and minimum mass and energy loss of the RCS, heat removal by the PRHRS was performed in the maximum break size (2-in.) accident, and heat removal by the PRHRS was not conducted in the minimum break size (7/32-in.) accident. The difference in mass and energy loss of the RCS will have a significant impact on the operation of the automatic depressurization system. Using the two extreme accident simulations, it was possible to confirm the difference in accident progression caused by the difference in break size and the characteristics of the PSIS.

中文翻译：

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使用 SMART-ITL 数据比较被动安全注入线上两种不同尺寸的小断点 LOCA

摘要 即使对于拆除所有大型管道的小型模块化反应堆（SMR），小断口冷却剂损失事故（SBLOCA）也是重要的设计基准事故（DBA）。在实现原型反应堆之前，SBLOCA 情景的实验模拟是必不可少的。系统集成模块化先进反应堆（SMART）是韩国原子能研究所开发的SMR之一。还构建了一个整体测试回路 SMART-ITL，以对原型反应器进行多种类型的整体热工水力效应测试。SMART-ITL 的设计具有保留的高度、1/7 的直径和 1/49 的面积以及体积缩放比。SMART-ITL 配备了两种类型的被动安全系统：被动安全注入系统 (PSIS) 和被动余热去除系统 (PRHRS)。PSIS 设计用于在事故发生后 72 小时内重新填充反应堆冷却剂系统 (RCS) 中的冷却剂。在事故条件下，PRHRS 使用两相自然循环防止 RCS 过热和过压。被动安全注入线上的 SBLOCA 是一个重要的 DBA，应该验证断裂尺寸的差异。在本文中，分析了两种不同断裂尺寸 2 和 7/32 英寸的影响，以研究 RCS 的最大和最小质量和能量损失的影响。为了模拟 RCS 最大和最小质量和能量损失之间的明显差异，在最大破裂尺寸（2 英寸）事故中进行了 PRHRS 排热，而在事故中未进行 PRHRS 排热。最小断裂尺寸（7/32 英寸）事故。RCS的质量和能量损失的差异将对自动减压系统的运行产生重大影响。使用这两个极端事故模拟，可以确认由断裂尺寸的差异和 PSIS 的特性引起的事故进展的差异。