Grant: NSERC/NRCan/AECL Generation IV Energy Technologies Program

There have been few activities related to fuel development and design during Phase 1 of the Canadian SuperCritical Water-Cooled Reactor (SCWR) Project. A 78-elements fuel bundle design is being proposed for theSCWR. Both the average core outlet coolant temperature (at 625 C) and pressure (at 25 MPa) are much higherthan those of the current CANDU reactors. This proposal is expected to help address several SCWR fueldesign issues by investigating the effects of fuel pellet and element geometries such as:- variation of diametral clearance and chamfer geometry to minimize pellet cladding interaction,- variation of the pellet microstructure to optimize fission gas release (FGR) and fracture resistance,- optimization of the pellet length/diameter ratio to facilitate heat transfer,- variation of cladding thickness to maximize heat transfer and minimize creep damage,- optimization of the element internal volume (void) to limit gas pressure,- optimization of the initial filling gas pressure to maintain good heat transfer and compensate the pressuredifference during the life of the fuel,- variation of the inner surface coating of the clad to absorb fission products, and- obtaining a desirable power distribution by optimizing pellet fissile content (grading).The effects of pellet geometries on FGR have been extensively studied by the Atomic Energy of CanadaLimited. To optimize cladding thickness, pellet geometry is a critical input. A code that is being developed bythe Royal Military College of Canada, based on a COMSOL Multiphysics platform, will be used to calculatesensitivities to various design parameters. This assessment is to demonstrate that FGR, sheath creep and fuelcenterline temperature are within their respective design needs. Pellet fissile content will also be optimized.