基于HFETR的快堆燃料短棒辐照试验方案设计与分析

综合考虑辐照试验指标与燃料试验安全、高通量工程试验堆（HFETR）运行要求、试验段压差波动等因素，基于HFETR开展了快堆燃料短棒辐照试验方案设计与分析，确定了铅铋合金层厚度、冷却水流道结构、阻力塞结构、冷却水流量等关键参数，获得了热棒包壳最高温度为(490±60)℃的高线功率密度辐照试验方案。试验结果表明，热棒最大线功率密度为68~85 kW/m时，包壳与燃料芯体温度满足辐照试验要求且留有余量；在200~300 kPa堆芯压差范围内，相同压差下试验段流量的计算流体力学（CFX）计算值比试验值偏小9% ~11%；试验段外侧窄缝流道的流量份额为7.3%，显著低于该流道的流通面积份额，满足线功率密度为85 kW/m时燃料短棒的冷却要求。本文提出的辐照试验方案可为快堆燃料棒的高线功率密度辐照试验提供参考。 

Design and Analysis of Irradiation Test Scheme for Fast Reactor Fuel Slug with HFETR

Considering the irradiation test index and fuel test safety, the operation requirements of high flux engineering test reactor (HFETR), the pressure difference fluctuation in the test section and other factors, in this paper, based on HFETR, the design and analysis of the fast reactor fuel slug irradiation test plan were carried out, and the key parameters such as the thickness of the lead-bismuth alloy layer, the structure of the cooling water channel, the structure of the thimble plug, and the flow rate of the cooling water were determined, and a high linear power density irradiation test plan with the maximum temperature of the hot rod cladding at (490±60)℃ was obtained. The results show that when the maximum linear power density of the hot rod is 68~85 kW/m, the temperature of the cladding and the fuel core meets the requirements of the irradiation test and has a margin; In the range of 200~300 kPa core pressure difference, the calculated CFX value of the flow in the test section under the same pressure difference is about 9%~11% smaller than the test value; The flow share of the narrow channel outside the test section is 7.3%, which is significantly lower than the flow area share of the channel, meeting the cooling requirements of fuel slugs when the linear power density is 85 kW/m. The irradiation test plan proposed in this paper can provide a reference for the high linear power density irradiation test of fast reactor fuel rods.