IMF燃耗特性与次锕系核素产量分析

在轻水堆中采用惰性基质燃料(IMF)能有效地从源头上降低乏燃料中次锕系核素(MA)的含量。为了研究IMF的燃耗特性,选取两种典型IMF方案PuO2+ZrO2+MgO和PuO2+ThO2,开展不同PuO2含量下IMF燃耗反应性计算,并与UO2燃料以及MOX燃料进行比较分析。结果表明:在总燃耗时间为1 095d情况下,两种IMF方案中PuO2体积分数为2%~10%时,其寿期末kinf均大于1,但PuO2+ZrO2+MgO方案的燃耗反应性波动大于PuO2+ThO2方案,PuO2+ThO2方案燃料寿期末MA的含量明显小于前者;在同一等效重金属质量分数下,MOX、UO2燃料寿期末MA的含量均大于两种IMF。

Study on Burnup Characteristics and MA Production of IMF

The adoption of inert matrix fuel (IMF) can effectively reduce the amount of minor actinide (MA) in spent fuel of LWR from the source. In order to study the burnup characteristics of IMF, the two typical IMF schemes of PuO₂+ZrO₂+MgO and PuO₂+ThO₂ were selected, and the IMF reactivity with different amounts of PuO₂ was calculated. And the comparison among IMF, UO₂ and MOX was made. The results show that after 36 months operating, with the PuO₂ volume fractions of two types of IMFs from 2% to 10%, their k_inf values at the end of cycle are all above 1. But the burnup reactivity of PuO₂+ZrO₂+MgO scheme is greater than that of PuO₂+ThO₂. The amount of MA at the end of cycle in PuO₂+ThO₂ scheme is obviously smaller than the former. Under the same effective heavy metal weight percentage, the amounts of MA in MOX and UO₂ fuels at the end of cycle are both greater than those of the two types of IMFs.