Numerical Study of Influence of 15N Enrichment on Burnup Performances for a Heat Pipe Cooled Traveling Wave Reactor

Abstract

Heat pipe cooled traveling wave reactor (HPTWR) is an advanced reactor design and shows great promise in the decentralized electricity markets due to its high power output, compact structure, and long lifetime. Based on the proposed HPTWR, the influences of 15N enrichment in the UN fuel on the burnup performances of the reactor are investigated in current study, aiming to provide an appropriate reference for the reactor with long-term continuous operation and a relatively low technology requirement for 15N enrichment. In this work, HPTWR with different 15N enrichments are analyzed to assess the burnup performances of the reactor. And key parameters (criticality, lifetime, propagation of axial power peak, 14N and 15N consumptions, and U-Pu breeding) are explored based on the Monte Carlo code RMC with the ENDF/B-VII cross-section database. The results show that the lifetime of reactor is increased with the increase of 15N enrichment. To maintain the propagation of neutron traveling wave, the 15N enrichment must be higher than about 85% in the HPTWR. The 15N enrichment of 99% in the HPTWR is appropriate and recommended. In this case, the HPTWR can achieve about 58.6-year continuous operation, and produce about 684.97 kg of 239Pu and 4.78 kg of 241Pu at the end of life.