Experimental study to assess effects of ballooning and fuel relocation on the coolability of fuel rod bundle

•Reflood experiments for the effects of clad ballooning and fuel relocation.•Intact, only ballooned, fuel relocated heater bundles were installed to compare.•The PCTs of all bundles increase for a low reflood rate and high power density.•The ballooned bundle shows similar behavior with the intact rod bundle.•The fuel relocated bundle had higher PCTs than the others for high power condition.