压水堆中嬗变99Tc和129I的计算研究

摘要

The feasibility of transmutation of long-lived fission product (LLFP) 99 Tc and 129 I in pressurized water reactor (PWR) ,baesd on Daya Bay PWR ,was analyzed .The calculation results show that the maximum transmutation rate is 15.69% for 99 Tc during one refueling cycle of 18 months ,and 9.18% for 129 I .By analyzing the safety related items of different reactor cores ,it is shown that ,after introducing LLFPs into PWR , the kef gets lower and the range of variation with burnup becomes small ,and obvious change of the radial neutron flux density of reactor core is not found ,but the radial power peaking factor is declined .And also ,there is no safety problems for reactivity coefficient and control after considering fuel temperature coefficient , moderator temperature coefficient ,differential soluble boron worth and control rod worth .On the contrary ,the above parameters get better .In summary ,transmutation of 99 Tc and 129 I in PWR is feasible .%选取大亚湾压水堆作为嬗变参考堆，研究在压水堆中嬗变长寿命裂变产物99 T c和129 I的可行性。计算结果表明：在1个换料周期（18个月）内，99 T c的最大嬗变率为15.69％，129 I的最大嬗变率为9.18％。通过对不同堆芯方案进行安全性分析发现：添加99 T c和129 I后，堆芯有效增殖因数kef降低且随燃耗变化的幅度变小；堆芯径向中子通量密度分布无明显变化但径向功率峰因子降低；考虑燃料温度系数、慢化剂温度系数、硼微分价值以及控制棒价值等，得出在反应性温度系数及反应性控制方面不会导致安全问题，相反有优化作用。因此，从安全角度分析，在压水堆中嬗变99 T c和129 I是可行的。