ABSTRACT A reduced order model (ROM) for a safety analysis code (RELAP/SCDAPSIM) is developed and is applied to the statistical safety analysis in order to reduce computational load. The ROM that reproduces output of the safety analysis code (e.g., the peak cladding temperature) is constructed using the singular value decomposition and the low-rank approximation for time-series data of a safety analysis code. A sampling method that incorporates dissimilarity among input data is tested to generate training data for the ROM. A loss of coolant accident with multiple failures of safety functions in a BWR is considered as an accident scenario. Statistical results such as the average, the standard deviation, and the 95% cumulative probability value of safety parameters obtained by the ROM and those obtained by the safety analysis code are compared. The reference results obtained by the direct random sampling method with the safety analysis code are within the 95% confidence interval of the results obtained by ROM. Thus the applicability and effectiveness of the ROM to the statistical safety analysis are confirmed through numerical analysis.

中文翻译：

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安全分析代码的降阶模型在统计安全分析中的适用性

摘要 开发了安全分析代码（RELAP/SCDAPSIM）的降阶模型（ROM）并将其应用于统计安全分析，以减少计算量。使用奇异值分解和安全分析代码的时间序列数据的低秩近似来构造再现安全分析代码的输出（例如，峰值包层温度）的ROM。结合输入数据之间的差异的采样方法被测试以生成 ROM 的训练数据。BWR 中安全功能多次失效的冷却剂损失事故被视为事故情景。将ROM获得的安全参数的平均值、标准偏差、95%累积概率值等统计结果与安全分析代码的统计结果进行比较。使用安全分析代码直接随机抽样方法获得的参考结果在ROM获得的结果的95%置信区间内。因此，通过数值分析证实了 ROM 对统计安全分析的适用性和有效性。