大型先进压水堆中次锕系核素嬗变特性

Transmutation characteristics of minor actinides in advanced pressurized water reactors

随着核电事业的快速发展,核电厂卸载的乏燃料越来越多。如何处置核电站乏燃料中的次锕系核素(MA)既是核燃料再利用的重要过程,又是闭式循环中的关键步骤。如果处置得当,不仅可以提高燃料的利用率,而且可以将MA变成同位素燃料电池、中子源等有用的核素。国际上认可的处置方法是分离-嬗变,但是嬗变MA的难点是嬗变堆型的选取和如何提高嬗变率。压水堆(PWR)是国内外最成熟的堆型和商业运行的主要堆型,也是现阶段最具有可能进行MA嬗变的堆型。于是,本文利用MCNP程序研究了压水堆嬗变MA的特性,通过研究MA嬗变棒的设计、添加位置和添加量等对压水堆堆芯有效增殖因子的影响,初步探索出最佳的压水堆嬗变MA的设计方案,为我国现阶段进行压水堆嬗变MA奠定了理论基础。

With the development of nuclear power industry, spent fuel of nuclear power plant is increasing. The disposal of minor actinides（MA） of spent nuclear fuel in nuclear power plants is not only an important process of recycling nuclear fuel, but also key step in the closed cycle. If MA can be disposed properly, the utilization rate of fuel can be improved, and MA can be turned into useful isotopes such as radionuclide fuel cell isotopes and neutron source isotopes and so on. Internationally accepted method of disposal is transmutation, but the difficulties of MA transmutation are how to select the type of transmutation reactor and how to improve the transmutation rate. Because the pressurized water reactor （PWR） is the most mature type of reactor and the main commercial operation reactor type, PWR has the most possibility to transmutate MA at this stage. Therefore, we did the research of the transmutation characteristics of MA with MCNP in PWR. Studying the design, layout and supplementation of MA transmutation rod and the influence on the effective multiplication factor, we explored the best transmutation MA design and technology directions in PWR. The results would lay the theoretical foundation for MA transmutation in PWR.