摘要: 钍基熔盐堆（Thorium Molten Salt Reactor，TMSR）核能系统先导专项的研究目标是研发第四代裂变反应堆核能系统（即钍基熔盐堆）。为充分利用液态燃料熔盐堆的在线添料与在线燃料处理的优势，同时考虑熔盐堆的快速部署，TMSR先导专项部署了小型模块化熔盐堆。考虑燃料处理技术现状及其可能的发展方向，小型模块化熔盐堆钍利用方案采用"三步走"战略。第一阶段采用在线加料与离线处理，实现钍的成规模利用；第二阶段采用在线加料和在线处理（U）与离线处理（MA）的结合，实现钍的高效利用；第三阶段采用在线加料及在线处理全部重金属，实现钍的自持增殖利用。随着"三步走"战略的逐步实施，钍铀燃料循环模式及后处理性能稳步提高，重金属利用率得到明显改善，同时有效降低了卸料毒性。考虑燃料许可容易度和建堆时间，首先为钍利用方案第一阶段布置了三种可能的启堆燃料，分别为低富集铀、低富集铀加钍和²³³U加钍。计算结果显示：以低富集铀启堆时，燃料循环性能与水堆相当；以²³³U启堆时，燃料利用率明显高于水堆，且其放射性毒性比水堆低约2个数量级。


The missions of the Thorium Molten Salt Reactor (TMSR) Nuclear Energy System are to research and develop the thorium based molten salt reactors (MSR) belonging to the fourth generation of nuclear fission reactor system. A Small modular Molten Salt Reactor (SmMSR) is deployed to make full use of the advantages of online refueling and online reprocessing and to consider the rapid deployment of MSR. An innovative "three-stage" strategy of thorium utilization based on SmMSR is proposed to take the current condition of fuel reprocessing and its future evolution. The first stage can realize the thorium utilization at a large scale with online refueling and off-line processing. The second stage can obtain efficient thorium utilization with online refueling, online processing of uranium and off-line processing of minor actinides (MAs). The third stage is implemented with self-sustaining or breeding mode with online refueling and online processing of all heavy metals. Along with the development of three stages, the utilization of heavy metals will be obviously improved and the radio-toxicity will be significantly reduced. A SmMSR is designed to achieve the goals of the first stage of thorium utilization. And three kinds of nuclear fuel cycles with different startup fuel types (i.e., low enriched uranium (LEU), thorium mixed with LEU (LEU+Th) and thorium mixed with ²³³U (²³³U+Th)) are implemented. The results show that the performance for fuel cycle containing LEU is comparable to the pressurized-water reactor (PWR). Meanwhile, the nuclear utilization for that containing ²³³U is much higher than PWR, and the radio-toxicity for which is lower by ~2 magnitudes than that for PWR.