Abstract Key parameters of Pebble Bed Advanced High Temperature Reactor (PB-AHTR) core are studied, and then the preferred core conceptual design is proposed. Both evacuating molten salt and injecting poison into coolant can be used as the auxiliary system of the second shutdown system in PB-AHTR. Compared with injecting poison into coolant, the effect of evacuating molten salt on the core is smaller and more beneficial to the engineering realization. Compared to one-time loading scheme, batch loading scheme can ensure that a small core excess reactivity in whole life-time which is easier to be controlled, but more complex to operation. In one-time loading scheme, the second shutdown system gains enough fast shutdown margins by increasing the number of second control rod, instead of reducing the stack height of core activity. The shutdown margins of both the first shutdown system and the second shutdown system meet the design requirements.

中文翻译：

---

球床先进高温反应堆优选堆芯概念设计

摘要 研究了球床先进高温反应堆(PB-AHTR)堆芯的关键参数，提出了优选的堆芯概念设计。排熔盐和向冷却剂注入毒物均可作为PB-AHTR二次停机系统的辅助系统。与向冷却剂中注入毒物相比，排出熔盐对堆芯的影响更小，更有利于工程实现。与一次性加载方案相比，批量加载方案可以确保整个生命周期内较小的堆芯过量反应性，更容易控制，但操作更复杂。在一次加载方案中，二次停堆系统通过增加二次控制棒的数量获得足够的快速停堆裕度，而不是降低堆芯活动的堆高。