Evaluation of Large 3600MWth Sodium-Cooled Fast Reactor Neutronic OECD Benchmarks

In the frame of the Working Party on Reactor and System (WPRS), an international mandate has been proposed to work towards a shared neutronic analysis of several Generation-IV Sodium-cooled Fast Reactor (SFR) concepts. This paper summarizes the results obtained for large cores benchmark by participants from numerous institutes of different countries (ANL, CEA, ENEA, HZDR, JAEA, KFKI, KIT, UIUC). This paper gathers results using different calculation methods and systems to estimate the core reactivity and isotopic composition evolution, neutronic feedbacks and power distribution. For the different core concepts analyzed, a satisfactory agreement between participants was obtained despite the different schemes of calculation used. A good agreement is generally obtained when comparing compositions after burnup, the delayed neutron fraction, the Doppler coefficient, and the sodium void worth. However, some noticeable discrepancies between the k-effective values were observed and are explained in this paper. These are mostly due to the different neutronic libraries employed (JEFF3.1, ENDF/B-VII.0 or JENDL-4.0) and in a less extend calculations methods.