Estimating Potential Tritium and Plutonium Production in North Korea’s Experimental Light Water Reactor

North Korea’s 100 MW-th Experimental Light Water Reactor (ELWR) began operating in late 2023. It is their third completed reactor and the first to use domestically-enriched fuel and pressurized water. While state officials claimed the ELWR is a testbed for a civilian nuclear energy program, we explore its dual-use potential for tritium and plutonium generation. With a single-batch core, the ELWR was found to be capable of producing 48 to 82 grams of tritium annually. This could supply 2 to 4 new boosted warheads every year, up to a maximum arsenal of 88 to 150 boosted warheads total. The ranges reflect uncertainties in the ELWR’s design, most importantly its fuel cladding. Presently, we believe weapon-grade plutonium production is an inefficient and unlikely option in the ELWR. Further monitoring with multispectral satellite imagery or electric grid simulations could clarify North Korea’s intentions with the ELWR, with significant implications for future nuclear rapprochement.