停堆碱性运行对“华龙一号”CIPS风险的影响研究

Study on the Effect of Alkali Shutdown Operation on HPR1000 CIPS Risk

为评估中广核“华龙一号”停堆碱性控制对燃料组件垢致轴向功率偏移风险(CIPS)的影响,本文从理论分析和软件计算两个角度进行了研究。结果表明,压水堆停堆碱性控制会显著减少燃料组件表面污垢的释放,主要表现为抑制镍铁氧化物(Ni_(x)Fe_(3-x)O_(4))的分解。该机组停堆碱性控制状态下燃料组件表面的污垢继承率约为85%,最大硼沉积质量为0.099 7 kg,评估结果为CIPS低风险。但相比停堆酸性控制,实施停堆碱性控制后的压水堆在后续燃料循环内发生CIPS的风险更高,具体风险等级还需结合机组的热工水力参数和一回路水化学环境进行评估。

In order to evaluate the effect of alkali condition during reactor shutdown on crud induced power shift(CIPS) for HPR1000 pressurized water reactor,theoretical analysis and calculation of independent copyright software were carried out respectively in the present work.The results show that the alkali shutdown condition significantly reduced the release of crud which was deposited on the fuel cladding,inhibiting the decomposition of nickel ferrite(Ni_(x)Fe_(3-x)O_(4)).For a running domestic PWR,the crud carryover between continuous cycles for a alkali shutdown condition was about 85%,the largest boron deposition mass on fuel assembles was about 0.099 7 kg,resulting in a low risk of CIPS.In comparison with the acid shutdown condition,the risk of CIPS happened in alkali shutdown condition was even higher.However,the specific risk level of CIPS should be evaluated in combination with the thermal hydraulic parameters and the primary water environment.