大晶粒UO2燃料芯块堆内试验组件的研制

为了开发高性能的压水堆燃料,研制了大晶粒燃料芯块。试验燃料芯块具有高的235U富集度、小直径和大晶粒尺寸的特点。通过堆内辐照试验可以对不同制造工艺的燃料芯块进行评价和筛选,以便确定燃料制造工艺。为了在中国原子能科学研究院池式研究堆中随堆考验,设计了一种试验组件,包含四根双包壳的燃料棒。双包壳燃料棒是在外包壳内装入两根单包壳燃料棒。试验组件直接由反应堆一次循环水冷却,不设专门的冷却回路。试验组件上安装了多种堆芯测量传感器,包括燃料中心温度热电偶、自给能中子探测器和冷却剂出、入口温度热电偶,可以在线监测燃料试验参数。描述了大晶粒UO2燃料芯块的研制、试验燃料组件的研制和检验。

Design and manufacture of in-pile irradiation fuel assembly with large grained UO2 pellets

The large grained UO2 pellets are developed for advanced PWR fuel.The test fuel pellets are of high 235U enrichment,thin diameter and large grain size.The objective of in-pile test is to evaluate fuel pellets which are manufactured by different fabrication processes.The fuel irradiation is conducted in the Swimming Pool Reactor(SPR) in China Institute of Atomic Energy.The test fuel assembly consists of four separated double cladding elements(similar to irradiation capsule) and each element includes two short fuel rods.The fuel assembly is cooled directly by primary water of SPR.Several kinds of sensors are fixed to the assembly,such as fuel centre-line thermocouple,Self-Powered Neutron Detectors(SPNDs),inlet and outlet coolant thermocouples,which enables on-line monitoring of test parameters.The paper introduces the design and manufacture of the large grained UO2 pellets and the test fuel assembly.