摘要
在发生反应堆严重事故时,熔融物堆内滞留(In-Vessel Retention,IVR)是一种非常有效和重要的严重事故缓解措施。反应堆压力容器下封头对于IVR策略的成功实施具有重要的作用。在IVR发生过程中,下封头处于高温环境中,其主要失效形式为蠕变失效。下封头一旦发生失效则有可能导致放射性物质释放到环境中。因此,为了确保IVR策略的成功实施,防止放射性物质泄漏,有必要开发一种有效的反应堆压力容器下封头的热蠕变模型从而对下封头进行深入分析。本文应用薄壳理论并结合诺顿-贝利蠕变方程开发了LHTCM(Lower Head Thermal Creep Module)模型,并使用四种失效准则分别对下封头的完整性进行评估。最终将LHTCM模型集成到一体化严重事故分析程序ISAA中对OLHF(OECD Lower Head Failure)实验进行了验证计算。通过对LHTCM模型中四种失效准则的分析,最终采用Larson-Miller准则的LHTCM模型预测的下封头失效时间与实验数据的相对误差仅在2.0%以内,并且其预测的下封头最底部伸长量与Kachanov准则等其他三种判据相比更加符合实验结果。结果表明:本文开发的LHTCM模型能够准确地预测下封头的蠕变行为,所计算的下封头失效时间、位置以及底部伸长量等与实验结果符合很好。
[Background] In the event of a reactor severe accident, in-vessel retention(IVR) is a very effective and important severe accident mitigation measure. The lower head of the reactor pressure vessel(RPV) plays an important role in IVR strategy. The lower head is in a high-temperature environment, and its main failure form is creep failure. Once the lower head fails, it may lead to the release of radioactive substances into the environment.[Purpose] This study aims to develop a thermal creep model for reactor pressure vessel lower head to ensure the successful implementation of IVR strategy and prevent radioactive material leakage, and apply this model to OECD lower head failure(OLHF) experiment analysis. [Methods] The thin shell theory and Norton-Bailey creep equation were employed to develop the lower head thermal creep module(LHTCM) model, and four failure criteria were used to evaluate the integrity of the lower head. Then, the LHTCM model was integrated into the integrated severe accident analysis program ISAA to verify and calculate the OLHF experimental data. [Results] Through the analysis of four failure criteria in LHTCM model, it is found that the relative error between the failure time of the lower head predicted by the LHTCM model using the Larson Miller criterion and the experimental data is within 2.0%, and its predicted the elongation at the bottom of the lower head is more consistent with the experimental data than the other three criteria such as Kachanov criterion. [Conclusions] LHTCM model developed in this study can accurately predict the creep behaviour of the lower head, and the calculated failure time, position and bottom elongation of the lower head are in good agreement with the experimental results.
作者
杨皓
张斌
高鹏程
唐绍伟
单建强
YANG Hao;ZHANG Bin;GAO Pengcheng;TANG Shaowei;SHAN Jianqiang(School of Energy and Power Engineering,Xi'an Jiaotong University,Xi'an 710049,China;State Key Laboratory of Multiphase Flow in Power Engineering,Xi'an Jiaotong University,Xi'an 710049,China)
出处
《核技术》
CAS
CSCD
北大核心
2022年第8期79-88,共10页
Nuclear Techniques
基金
中核集团领创科研基金(No.J201912021-23)资助。
