Design improvement of an OPT-H type nuclear fuel rod support grid by using an axiomatic design and an optimization

Abstract: A nuclear fuel rod support grid is an important structural part of a nuclear fuel assembly which is used in a pressurized light water reactor. It provides a flexible support for the nuclear fuel rods which experience a severe thermal expansion and a contraction caused by the harsh operational conditions in the core of a reactor. Diverse design requirements should be set for the performances of the multidisciplinary natures such as an impact resistance, spring characteristics, possible amount of a fretting wear on the fuel rods, the coolant flow and heat transfer around it, and so on. In this paper, an effort is reported to improve the impact resistance of an OPT-H type support grid, a high performance spacer grid developed by the Korea Atomic Energy Research Institute. A systematic approach by using an axiomatic design and optimization is utilized for this purpose.