Fault trees (FT) and event trees (ET) are widely used in industry to model and evaluate the reliability of safety systems. This work seeks to analyze and estimate the core damage frequency (CDF) due to flow blockage (FB) and loss of coolant accident (LOCA) due to large rupture of primary circuit pipe with respect to a specific 10 MW Water-Water Research Reactor in Ghana using the FT and ET technique. Using FT, the following reactor safety systems: reactor protection system, primary heat removal system, isolation of the reactor pool, emergency core cooling system (ECCS), natural circulation heat removal, and isolation of the containment were evaluated for their dependability. The probabilistic safety assessment (PSA) Level 1 was conducted using a commercial computational tool, system analysis program for practical coherent reliability assessment (SAPHIRE) 7.0. The frequency of an accident resulting in severe core damage for the internal initiating event was estimated to be 2.51e − 4/yr for the large LOCA as well as 1.45e − 4/yr for FB, culminating in a total core damage frequency of 3.96e − 4/yr. The estimated values for the frequencies of core damage were within the expected margins of 1.0e − 5/yr to 1.0e − 4/yr and of identical sequence of the extent as found for similar reactors.

中文翻译：

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流动堵塞和冷却剂损失事故堆芯损坏频率的分析和估计：以10 MW水-水研究堆-PSA 1级为例

故障树 (FT) 和事件树 (ET) 在工业中被广泛用于对安全系统的可靠性进行建模和评估。这项工作旨在分析和估计由于流动阻塞 (FB) 和冷却剂损失事故 (LOCA) 导致的堆芯损坏频率 (CDF) 与特定 10 MW 水-水研究堆的一次回路管道大破裂有关。加纳使用 FT 和 ET 技术。使用 FT，评估了以下反应堆安全系统的可靠性：反应堆保护系统、一次排热系统、反应堆池隔离、紧急堆芯冷却系统 (ECCS)、自然循环排热和安全壳隔离。概率安全评估 (PSA) 1 级是使用商业计算工具进行的，实用相干可靠性评估系统分析程序 (SAPHIRE) 7.0。内部始发事件导致严重堆芯损坏的事故频率估计为 2.51Ë  -为对大LOCA 4 /年以及1.45 ë  -用于FB 4 /年，在3.96的总核心损坏频率最终ë  - 4 /年。堆芯损坏频率的估计值在 1.0 e  - 5/年到 1.0 e  - 4/年的预期范围内，并且与类似反应堆发现的程度序列相同。