An estimation of weapon-grade plutonium production from 5 MWe YongByon reactor through MCNP6 core depletion analysis

Abstract

The estimation of the fissile inventories (Weapon-Grade (WG) plutonium and enriched uranium) from 5 MWe Yong-byon reactor is important to evaluate North Korea's capability to produce nuclear weapons. In this work, the inventories of WG plutonium are estimated using a detailed depletion analysis with MCNP6 core modeling, based on the operation histories of the reactor given in the open literatures. In particular, the estimated inventories are compared with those obtained using the previous simple method suggested by Albright and ORIGEN-S. Also, the detailed depletion analysis gives the WG plutonium inventory distribution over the core, which makes it possible to estimate the WG plutonium inventory when reprocessing is applied to the partially unloaded fuels. The calculation results show that the WG plutonium inventories at the end of 2015 estimated using MCNP6 core model and ORIGEN-S point depletion are lower by 5.5–4.3% and higher by 11.7–12.6%, respectively, than those estimated by Hecker et al. In addition, low and high estimates of WG plutonium productions after 2015 were estimated based on the information given in the literatures and assumptions on the capacity factor and irradiation times.