(U,Zr)C Mixed Carbide Fuel Coatings Using Impulse PVD

NTP hasnbsp;multiple goals ranging from higher exhaust temperature (gt;1000s Isp), hot corrosion resistance (diverse propellants: H2, CH4, NH3, H2O), higher power density (thrust, gt;5MW/L goal), local fission product retention (materials damage, migration), manufacturability (cost, materials), safety (ground testing, flight), long core lifetime for interplanetary round trips (single fuel load, good burnup, control, 5+ years), and commonality with terrestrial applications (SMR, MNR, industrial heat, DoD/Pele) and advanced applications like reusable hypersonics, Luna/Mars surface power).nbsp;A solution, called the Coated Mixed Carbide (CMC) fuel element approach, is a hybrid between distributed solid-solution carbides from the Rover/NERVA days and localized TRISO fuel from todayrsquo;s small modular reactor concepts.nbsp; Very high temperature ~3500Knbsp;(U,Zr)C fuel is concentrated in small kernels and protected against attack bynbsp;hydrogen from outsidenbsp;and from fission products within by engineered multilayered coatings.nbsp; An recent innovationnbsp;in high-powernbsp;impulse magnetron sputtering (i.e.nbsp;IMPULSEreg; + Positive Kicktrade;) allows conformalnbsp;coatings of thenbsp;small-diameter fuel kernels with lsquo;TRIZO-likersquo; protective layers to enable high-power density NTP reactors.nbsp; With precision ion energy and deposition flux control, each multilayer can be engineered for specific property, such as fission gas retention, compressive stress, hydrogen permeability, ductility, etc.nbsp;These #39;TRIZO-like#39; pellets are embedded in a ZrC(W) matrix and distributed for lower peaking factor across the fuel element.nbsp; Embedded propellant channels can be used for direct nuclear thermal propulsion or bimodal heat pipe power extraction for electrical power generation.This Phase I SBIR builds on three patent-pending technologies and seeks to demonstrate feasibility of the concept, identity and rank technical risks and prioritize investment in Phase II towards retiring the necessary risks.