15-15Ti cladding behavior during a RIA type event in TRIGA reactor

Abstract Pellet cladding mechanical interaction (PCMI) is a potential failure mechanism for fuel claddings during a Reactivity Initiated Accident (RIA) type event, thus preventing failure of the cladding material during transient conditions is considered one of the primary safety criteria to ensure fuel element integrity. Eight irradiation experiments aimed to validate the experimental setup and test methodology developed in the frame of the MAXSIMA (Methodology, Analysis and eXperiments for the Safety In MYRRHA Assessment) project have been carried out in the Annular Core Pulse Reactor (ACPR) TRIGA core at Technologies for Nuclear Energy State Owned Company (RATEN) – Institute for Nuclear Research (ICN), Pitesti, Romania. Cladding damage due to PCMI in terms of cladding mechanical strain was measured. In Partitioning And Transmuter Research Initiative in a Collaborative Innovation Action (PATRICIA) Project, a work package, is dedicated to obtaining and processing information from fuel segments exposed to power transient during the abovementioned experiments. This paper includes the results of TRANSURANUS and ANSYS thermo-mechanical modelling of one experimental fuel element, consisting in UO 2 with a higher enrichment of about 18 % 235 U and 15-15Ti clad, surrounded by lead bismuth eutectic (LBE). The selected fuel element was exposed in a double pulse test. The results are discussed concerning both fuel and cladding performance and compared with available experimental data and gave positive indications about Multi-purpose hYbrid Research Reactor for High-tech Applications (MYRRHA) type fuel element behavior under RIA conditions.