LOCA工况下事故容错燃料对燃料棒性能影响的初步分析研究

Preliminary Analytical Study of the Effect of Accident Tolerant Fuel on Fuel Rod Performance under LOCA Condition

事故容错燃料(ATF)包壳材料是在福岛核事故后为了提高燃料元件抵御严重事故的性能而提出的新一代核燃料概念,与目前的Zr-4合金包壳相比,ATF包壳材料能够在较长时间内抵御事故后果,同时还能保持或提高其在正常运行工况下的性能。基于FRAPTRAN-2.0程序,针对两种ATF包壳材料(FeCrAl和SiC),通过改进包壳材料热物性模型、包壳力学行为模型和氧化模型,开发了适用于ATF包壳材料的燃料棒性能瞬态分析程序。以MT-1实验台架的燃料棒为对象,对其失水事故(LOCA)工况进行计算分析,研究了ATF包壳材料在该事故工况下的热工水力瞬态响应特性。结果表明,相比传统的Zr-4合金包壳,ATF包壳材料不仅可以降低LOCA下的包壳峰值温度,还能延缓或防止包壳失效。

Accident tolerant fuel(ATF)cladding material is a new generation of nuclear fuel concept proposed after the Fukushima nuclear accident to improve the performance of fuel elements against severe accidents.Compared with the current Zr-4 alloy cladding material,ATF cladding material can resist the consequences of accidents for a long time,while maintaining or improving its performance under normal operating conditions.In this paper,based on the code FRAPTRAN-2.0 and two ATF cladding materials(FeCrAl and SiC),a transient analysis code of fuel rod performance for ATF cladding materials was developed by improving the thermalphysical model,mechanical behavior model and oxidation model of cladding materials.Then the fuel rods of the MT-1 experimental stand were used as the objects for the computational analysis of its LOCA condition,and the thermal-hydraulic transient response characteristics of ATF cladding materials under this condition are studied.The analysis results show that compared with the conventional Zr-4 alloy cladding,the ATF cladding material can not only reduce the peak cladding temperature(PCT)under LOCA,but also delay or prevent cladding failure.