Development Status of Accident-tolerant Fuel for Light Water Reactors in Korea

TLDR

The nuclear industry prioritizes safe, reliable, and economic operation of light water reactors, and the Fukushima incident spurred intense research into accident‑tolerant fuel (ATF). In Korea, ATF concepts are being developed to enhance fuel safety and reliability during normal operations, transients, and accident events. ATF pellets are being developed as microcell UO₂ and high‑density composite pellets, paired with surface‑modified Zr‑based alloy or SiC composite cladding to improve fission‑product retention and suppress hydrogen explosions and radionuclide release.

Abstract

For a long time, a top priority in the nuclear industry was the safe, reliable, and economic operation of light water reactors. However, the development of accident-tolerant fuel (ATF) became a hot topic in the nuclear research field after the March 2011 events at Fukushima, Japan. In Korea, innovative concepts of ATF have been developing to increase fuel safety and reliability during normal operations, operational transients, and also accident events. The microcell UO2 and high-density composite pellet concepts are being developed as ATF pellets. A microcell UO2 pellet is envisaged to have the enhanced retention capabilities of highly radioactive and corrosive fission products. High-density pellets are expected to be used in combination with the particular ATF cladding concepts. Two concepts—surface-modified Zr-based alloy and SiC composite material—are being developed as ATF cladding, as these innovative concepts can effectively suppress hydrogen explosions and the release of radionuclides into the environment.