压水堆中嬗变99Tc和129I的计算研究

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⁹⁹Tc和¹²⁹I的可行性。计算结果表明：在1个换料周期（18个月）内，⁹⁹Tc的最大嬗变率为15.69%，¹²⁹I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⁹⁹Tc和¹²⁹I后，堆芯有效增殖因数k_eff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⁹⁹Tc和¹²⁹I是可行的。

Computational Study on Transmutation of 99Tc and 129I in Pressurized Water Reactor

The feasibility of transmutation of long lived fission product (LLFP) ⁹⁹Tc and ¹²⁹I 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 ⁹⁹Tc during one refueling cycle of 18 months, and 9.18% for ¹²⁹I. By analyzing the safety related items of different reactor cores, it is shown that, after introducing LLFPs into PWR, the k_eff 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 ⁹⁹Tc and ¹²⁹I in PWR is feasible.