Full-core SSCWR calculations applying a fast computational method

The Supercritical Water-Cooled Reactor (SCWR) is a generation IV reactor concept which uses supercritical pressure water as coolant. By now, several versions of these concepts have been developed. A new thermal design called Simplified SCWR (SSCWR) was proposed in Reiss et al. (2010): the most important characteristics of the assembly are partial-length zirconium-hydride rods as extra moderator, axially varying fuel enrichment and a longer active length; also, the core had a smaller diameter compared to the original SCWR concept.This new type of assembly is optimized taking into account the neutronic and thermal-hydraulic properties. A one-pass core consisting of these assemblies is examined. Full-core calculations are computationally very expensive, thus a step-by-step homogenization process – complemented with extensive validation work – is applied using the code system SCALE6.0. This approach enabled a preliminary optimization of the one-pass core resulting in a favourable power distribution.This paper presents the outcome of the optimization of the assembly (fuel pin diameter 8.0 mm, pitch 10.12 mm, P/D 1.1), the developed fast computational method and the preliminary results of the full-core calculations (average fuel enrichment around 6.0%, radial power peaking below 1.3, maximum coolant temperature below 800 K and maximum cladding temperature below 850 K).