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利用有限元方法分析了堆芯熔融严重事故下反应堆压力容器(RPV)器壁的应力分布,探讨了RPV结构的失效模式,提出了RPV结构分层失效模型,可将RPV沿壁厚由内到外分为5个层面,即熔化区、高温蠕变主导区、压缩塑性主导区、弹性区和拉伸塑性区.分析了RPV塑性失效和高温蠕变失效的影响因素,并给出了塑性失效和高温蠕变失效的载荷条件.结果表明:内压是塑性失效的主要影响因素,随着内压增大,RPV壁内弹性层会逐渐减小,弹性层消失时对应的内压即为塑性失效的载荷条件;在蠕变条件下,当内压达到一定值后,截面塑性区、蠕变应变和塑性应变迅速增大,RPV达到极限状态,此时的内压即为高温蠕变失效的载荷条件.
The finite element method was used to analyze the stress distribution in reactor pressure vessel (RPV) wall under the serious accident of core melting. The failure mode of RPV structure was discussed and the layered failure model of RPV structure was put forward. The outer layer is divided into five levels, namely melting zone, high temperature creep dominant zone, compression plastic dominant zone, elastic zone and tensile plastic zone.The influencing factors of RPV plastic failure and high temperature creep failure are analyzed, and the plastic failure And the failure conditions of high temperature creep failure.The results show that the internal pressure is the main factor of plastic failure, as the internal pressure increases, the elastic layer in the RPV wall will gradually decrease, the corresponding internal pressure plastic layer disappears when the elastic layer disappears Under the creep condition, when the internal pressure reaches a certain value, the plastic zone, the creep strain and the plastic strain of the cross section rapidly increase, and the RPV reaches the limit state, and the internal pressure at this time is the failure of high-temperature creep failure Load conditions.