Analysis of the physical characteristics of damaged fuel assemblies after repair

Damaged fuel assembly which being repaired can be used in reactor only after evaluation and nuclear safety being ensured for the reactor. This report takes CPR1000 unit with AFA3G fuel assembly as the research object, and analyzes the physical characteristics and power distribution of normal fuel assembly and damaged fuel assembly after repair. It can be found that the effect on fuel assembly reactivity is very small for the fuel assembly replaced with a stainless steel rod, and the effect can be ignored. The more stainless steel bars been inserted in the fuel assembly, the greater magnitude of the fuel assembly reactivity changes. The fuel assembly reactivity variation range also increases along with burnup increase. The relative power of fuel rods which near stainless steel rod increase slightly. The relative power of the fuel rods farther away from the stainless steel rod does not change. The power peak still remained in the same quadrant. (authors)