Enhanced crud resistance of CrAl coated ATF claddings in simulated PWR conditions

In addition to oxidation resistance, an improvement of corrosion resistance is another important issue in the accident tolerant fuel development emerged after Fukushima accident. Crud deposited on fuel assembly induces undesired problems such as power shift, accelerated corroion of claddings which can ultimately results in fuel failure. In this study, an uncoated Zircaloy-4 cladding and a CrAl-coated Zircaloy-4 cladding are tested in simulated PWR water. In a CrAl-coated cladding crud adhesion is significantly reduced, along with reduction of crud thickness. Morphology and chemical characteristics of crud indicate that CrAl coating effectively works on reduction of crud deposition.