A little old (2021) but still interesting.
National Lab Creates New Device to Test Safety Limits of Nuclear Fuel
https://www.energy.gov/ne/articles/national-lab-creates-new-device-test-safety-limits-nuclear-fuel#:~:text=Critical%20Heat%20Flux%20Test%20at%20Idaho%20National%20Laboratory,nuclear%20fuel%20pin%20when%20it%20starts%20to%20overheat.