b'CHF Studies - Merging M&S, Out-of-pile and In-pile ExperimentsPrincipal Investigator: Colby Jensen, INLTeam Members/ Collaborators: Nicolas Woolstenhulme and Charles Folsom (INL), Richard Christensen (University of Idaho), Nicholas Brown (University of Tennessee Knoxville)Unique capability at the TREAT facility to study in-pile critical heat flux may provide the primary building block to allow for a change in the current fuel safety criteria and enable safe operation at higher powers, which result in a substantial increase in the performance of current and future LWRs.C ladding-to-coolant heat transferinvestigate transient and accident during transient irradiationscenarios involving critical heat flux conditions remains a critical area(CHF) in LWR systems.of uncertainty in understanding nuclearProject Description:reactor safety. This uncertainty impactsThe availability of the TREAT facility analytical predictions of both accidentwith its unique accessibility for progression and fuel performanceinstrumentation is ideally suited to behavior.This uncertainty manifestsfundamentally advance understanding itself in the use of conservative modelsof nuclear reactor safetyin that widely bound the onset andparticular, transient and accident duration of transition phenomena. scenarios involving CHF in LWR Improved understanding and predictivesystems. This project is developing models to describe the transitions toan in-pile experiment for TREAT to film boiling and its duration, as wellanswer key questions regarding CHF as improved material performanceunder prototypic irradiation with through accident tolerant fuel (ATF),specific interest in transient conditions could meaningfully increase safety andwith close integration of modeling design margins in both the currentand simulation and in- and out-of-pile commercial fleet and advanced lightexperimental facilities. The modeling water reactors (LWRs) (including smalland out-of-pile experimental scope modular reactors). Experiments areof this project will extend to fully currently being developed to leverageprototypic LWR thermodynamic the Transient Reactor Test Facilityconditions while in-pile experimental (TREAT) reactor, with its uniquetesting is focused on transient and accessibility for instrumentation, toirradiation effects. The following 130 2019|AFC ACCOMPLISHMENTS'