SmAHTR-CTC neutronic design

Building on prior experience for the 2010 initial Small Advanced High-Temperature Re-actor (SmAHTR) neutronic design and the 2012 neutronic design for the Advanced High-Temperature Reactor (AHTR), this paper presents the main results of the neutronic design effort for the newly repurposed SmAHTR-CTC reactor concept. The results are obtained based on full-core simulations performed with SCALE 6.1. The dimensionality of the SmAHTR design space is reduced by using constraints originating in material fabricability, fuel licensing, molten salt chemistry, and thermal-hydraulic and mechanical considerations. The new design represents in many regards a substantial improvement from the neutronic performance standpoint over the 2010 SmAHTR concept. Among other results, it is shown that a fuel cycle length of over two years or discharged fuel burnup of 40 gigawatt-day per metric ton of initial heavy metal are possible with an 8% fuel enrichment in a once-through fuel cycle, while eight-year once-through fuel cycle lengths are possible at higher fuel enrichments.