Improvement and Application of Computational Tools for New Fuel and Reactor Designs

Office of Nuclear Regulatory Research

The MELCOR severe accident code; the FAST fuel performance code and its predecessors, FRAPCON and FRAPTRAN; and the SCALE reactor physics, isotopic, criticality, shielding code and sensitivity uncertainty have been used to support NRC research, licensing, and oversight activities for more than four decades. For much of this time, the codes have been applied to lightwater reactors (LWRs) fueled by uranium dioxide fuel in zirconium alloy cladding. Recent interest in new accident tolerant fuel (ATF) types and in new and advanced reactors has prompted the NRC to update our computer codes and analysis methodologies and to apply them in an innovative way to this new class of fuel and reactor designs. This exhibit will explain past applications of the MELCOR, SCALE, and FAST/FRAP codes and describe new features that are being added to address new designs. Examples of these new features include the ability to model ironchromiumaluminum (FeCrAl) cladding in LWRs and to model gas-cooled reactor, heat-pipe reactor, and molten salt cooled reactor behavior in MELCOR; the addition of new metallic fuel and ATF material properties to the FAST code; and updated nuclear data and the ability to model the operational and safety needs for LWRs (e.g., ATF designs, including FeCrAl, chromium-coated claddings, and doped fuel; new fuel strategies using high-assay, low-enriched uranium/high burnup fuel; and advanced reactors (heat pipe reactors, gas-cooled pebble bed reactors, fluoride cooled pebble reactors, molten-salt-fueled reactors, and sodium fast reactors)) in the SCALE package. Additionally, MELCOR and SCALE are being used to develop source terms for high burnup fuels and ATF. Together, MELCOR, SCALE, and FAST will help support timely reviews of ATF and new reactor designs to ensure public health and safety. 

Exhibitor: James Corson, Reactor System Engineer (Fuel Analyst), RES/NRC, 301-415-2458, 

Page Last Reviewed/Updated Wednesday, April 7, 2021