Overview of the physics challenges in design of new energy systems

Abstract

Today's energy systems have diverse objectives catering to enhanced safety, ease of operation and better fuel utilization both for power generation and several other applications of nuclear reactions. Bhabha Atomic Research Centre (BARC) has been engaged in the design of new energy systems such as Advanced Heavy Water Reactor (AHWR), Indian Pressurised Water Reactor (IPWR), Molten Salt Reactor (MSR) and High Temperature Reactors (HTRs). The design optimisation of these reactors has varied challenges as they involve new fuel, newer materials, complex geometries, and inherent safety. AHWR, MSR and HTRs based on thorium fuel cycle while IPWR is optimized for longer cycle length with enriched uranium. HTRs are being developed as nuclear power packs for remote areas and they have interesting physics features of long-life cores and hence more challenging to be modelled.New designs use new materials and therefore require updated thermophysical and neutronic properties. Neutron-nuclear interaction cross sections are required in uncharted regimes. Modelling of physical phenomena in an MSR or HTR is very different than in water-cooled reactors.The neutronic tools also are required to be made state-of-the-art in order to model these multi physics phenomena. An exercise was taken up for a coupled neutronic-thermal hydraulic simulations for the natural circulation based boiling water cooled AHWR. Several new algorithms were also developed for fuel management of advanced thermal reactors. Monte Carlo methods and improved deterministic methods have been continuously developed. This paper brings out the challenges in design of these advanced reactors and the need for new experiments and irradiations of new fuel in research reactors.