华龙一号反应堆下腔室结构优化设计

在华龙一号反应堆结构设计中，为提高反应堆结构的安全性，将堆芯测量探测器从反应堆下腔室引出改为从反应堆压力容器顶盖引出，下腔室结构发生改变，影响了堆芯入口流场的均匀性，故需要重新设计下腔室搅混结构以使流场分布均匀。通过对比百万千瓦级国产化二代改进型压水堆（CNP1000）、百万千瓦级先进非能动型压水堆（AP1000）及欧洲先进压水堆（EPR）3种堆型反应堆下腔室结构，结合华龙一号自身下腔室结构特点，借鉴其他堆型以及提出新型结构，共提出了4种结构优化方案，分别对不同方案进行建模并利用计算流体力学（CFD）分析软件进行计算，从结构、制造、安装及流场分析等方面对4种新型下腔室搅混结构和CNP1000下腔室搅混结构进行对比分析，得出采用流量分配板结构的反应堆下腔室搅混结构为最优方案，其既能均匀搅混下腔室流场，又能使堆芯入口流量分配均匀。 

Optimization Design of HPR1000 Reactor Lower Plenum Structure

In the design of HPR1000?reactor structure, in order to improve the structure safety, the in-core instrumentation detector is guided out of the reactor from the vessel head?instead of?the lower plenum. The?structure?of the lower plenum?has?been?changed, which?affects?the uniformity of?the?inlet flow field, so a new lower plenum structure is needed. The reactor lower plenum structures of?CNP1000, AP1000 and EPR?are compared. Based?on the characteristics?of HPR1000, four schemes?for optimum structures are presented. By modeling and CFD analyzing, the four schemes?and that for CNP1000 are contrasted and analyzed in terms of?structure, manufacture, assembling and flow field analyzing. It is found that?the program which uses flow distribution plate is the best, and the uniformity of coolant mixing and flow distribution at the core inlet can be?satisfied.