Fusion power plant performance analysis using the HERCULES code

The HERCULES code was developed to assist in the safety and environmental analysis tasks of the European Power Plant Conceptual Study (PPCS). Its capabilities, however, extend beyond this kind of assessments. Coupling of the different computational tools and nuclear databases to the same geometry and material compositions, automation of input file generation and post-processing subroutines enable self-consistent calculations and radial-poloidal analyses of several parameters of interest in fusion technology design, optimising time and computer resources. Results include 2D variations of the neutron flux distribution and energy spectra, material activation and related quantities, wall loading, nuclear primary heating, tritium and helium production and radiation damage rates to materials. The capabilities of the neutron transport module of HERCULES are presented here and benchmarked on the PPCS models. Results are consistent with values assumed in the design process or obtained through the more specific PPCS analyses: tritium generation ratios are in the range between 1.12 and 1.36, energy multiplication between 1.16 and 1.39, and average wall loads between 1.90 and 2.54 MWm-2. Issues related to tritium breeding and possible tungsten first wall coating of the near-term models are discussed