b'ATF Cladding Tube Mechanical EvaluationPrincipal Investigator: Ben EftinkTeam Members/ Collaborators: Mathew Hayne, Peter Beck, James Valdez, Cheng Liu, Thomas Nizolek, Tarik Saleh,Stuart Maloy, and Ben Eftinkrequire special considerations. Testing the tensile properties in the axial (length of the tube) direction is straightforward, however, does not always translate to the hoop direction properties due to microstructural anisotropy from tube extrusion processing. Since the hoop direction is the direction that sees the greatest stress in real world situations, it is necessary to test the hoop direction mechanical properties directly.Project Description: This project had two main technical objectives: 1) evaluate the hoop direction mechanical properties of accident tolerant Cr coated Zircaloy and FeCrAl alloys and 2) further the understanding of the ringpull mechanical testing technique. The project team included an early career staff member, postdoc, and a Figure 1. Graduate student Peter BeckA ccident tolerant fuel clad- graduate student visiting as part of (left) and postdoc Mathew Hayne (right)dings of FeCrAl and Cr coateda Nuclear Energy University Project performing ringpull testing with DIC onZircaloy alloys provide safety(NEUP; see Figure 1).Cr coated Zircaloy. Testing is conducted on a miniature and portable load frame,improvements for light water reactorImplementing accident tolerant bottom right, mounted to an optical(LWR) fuel claddings. These materialscladding concepts in the next few years table. Computer monitor shows theare being studied for early imple- requires confidence in the claddings view of the DIC cameras.mentation in LWRs. Understandingmechanical performance. This includes how they respond to mechanicalunderstanding the tubes response stress, particularly in the hoopin the hoop direction and for the Cr direction of the tube is necessarycoated Zircaloy material, the integrity before wide implementation. Forof the coating during mechanical Cr coated Zircaloy tubes, specifi- loading. By mechanical testing of these cally the integrity of the Cr coatingcladding tubes, we are understanding during mechanical loading is notbetter how they will hold up in service known. Evaluating cladding tubesconditions including high mechanical mechanically in the hoop directionsstrain (due to internal gas pressure) is challenging and testing methodsaccident scenarios. This directly 114 2021|AFC ACCOMPLISHMENTS'