FCM燃料压水堆弥散可燃毒物中子学分析

Neutronic Analysis on Homogeneous Mixing Burnable Poison in PWR Loaded with FCM Fuel

为将全陶瓷微胶囊封装(FCM)燃料应用于小型压水堆,对FCM燃料组件开展了可燃毒物中子学设计与分析。通过寿期初引入负反应性、寿期内消耗速率和寿期末残留3个方面,对弥散在SiC基体中的弥散型可燃毒物Gd2O3、Er2O3、Sm2O3、Eu2O3、Dy2O3及HfO2进行评价。FCM燃料中TRISO颗粒核芯直径达800μm,燃料颗粒自屏效应强烈,在RMC程序中引入随机介质计算功能,对FCM燃料进行随机几何建模,保证了反应性计算精度。分析表明:Er2O3可作为FCM燃料堆芯的候选可燃毒物,Gd2O3和Eu2O3需结合堆芯开展进一步研究,Sm2O3、Dy2O3及HfO2的反应性惩罚过大,不适合作为FCM燃料可燃毒物。

Aiming to apply the fully ceramic microencapsulated (FCM) fuel in small module pressurized water reactor (PWR), neutronic design and analysis on burnable poisons were carried out. The homogeneous mixing burnable poisons embedded in silicon carbide (SiC) matrix, such as Gd2O3, Er2O3, Sm2O3, Eu2O3, Dy2O3 and HfO2, were studied via comparing the initial reactivity worth of the burnable absorber, the rate of burnup and the residual negative reactivity worth. The tristructural isotropic (TRISO) particle kernel in the concept FCM fuel design was up to 800 μm, thus the random geometry capability was developed in RMC code to treat the significant self-shielding effect. It is found that Er2O3 is excellent in integrated neutronics performance, thus can be used as burnable poison for FCM fuel loaded PWR. Gd2O3 and Eu2O3 are identified as candidate burnable poisons for further study. Sm2O3, HfO2 and Dy2O3 are not capable for burnable poison.