Nguyen Xuan Ha, Jang Seongdong, Kim Yonghee
Department of Nuclear and Quantum Engineering, Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Yuseong-gu, Daejeon, 34141, Republic of Korea.
Sci Rep. 2021 Jun 18;11(1):12891. doi: 10.1038/s41598-021-92350-5.
A novel re-optimization of fuel assembly and new innovative burnable absorber (BA) concepts are investigated in this paper to pursue a high-performance soluble-boron-free (SBF) small modular reactor (SMR), named autonomous transportable on-demand reactor module (ATOM). A truly optimized PWR (TOP) lattice concept has been introduced to maximize the neutron economy while enhancing the inherent safety of an SBF pressurized water reactor. For an SBF SMR design, the 3-D centrally-shielded BA (CSBA) design is utilized and another innovative 3-D BA called disk-type BA (DiBA) is proposed in this study. Both CSBA and DiBA designs are investigated in terms of material, spatial self-shielding effects, and thermo-mechanical properties. A low-leakage two-batch fuel management is optimized for both conventional and TOP-based SBF ATOM cores. A combination of CSBA and DiBA is introduced to achieve a very small reactivity swing (< 1000 pcm) as well as a long cycle length and high fuel burnup. For the SBF ATOM core, safety parameters are evaluated and the moderator temperature coefficient is shown to remain sufficiently and similarly negative throughout the whole cycle. It is demonstrated that the small excess reactivity can be well managed by mechanical shim rods with a marginal increase in the local power peaking, and a cold-zero shutdown is possible with a pseudo checker-board control rod pattern. In addition, a thermal-hydraulic-coupled neutronic analysis of the ATOM core is discussed.
本文研究了一种新型的燃料组件重新优化和新型创新可燃吸收体（BA）概念，以追求一种高性能的无硼（SBF）小型模块化反应堆（SMR），即自主按需运输反应堆模块（ATOM）。引入了一种真正优化的压水堆（TOP）栅格概念，以在提高SBF压水堆固有安全性的同时最大化中子经济性。对于SBF SMR设计，采用了三维中心屏蔽BA（CSBA）设计，并在本研究中提出了另一种创新的三维BA，即盘式BA（DiBA）。从材料、空间自屏蔽效应和热机械性能方面对CSBA和DiBA设计进行了研究。针对传统和基于TOP的SBF ATOM堆芯，优化了低泄漏两批燃料管理。引入CSBA和DiBA的组合，以实现非常小的反应性摆动（<1000pcm）以及长循环长度和高燃料燃耗。对于SBF ATOM堆芯，评估了安全参数，并且慢化剂温度系数在整个循环中显示出足够且相似的负值。结果表明，通过机械补偿棒可以很好地控制小的过剩反应性，局部功率峰值仅有少量增加，并且采用伪棋盘式控制棒模式可以实现冷零停堆。此外，还讨论了ATOM堆芯的热工水力耦合中子学分析。
