A bstract Particle production induced by a time-dependent background is well understood as the projection of time-evolved initial state onto set final states. While asymptotic and states are defined in usual way, definition particles antiparticles at intermediate times presence external fields ambiguous. These moreover induce divergences which require regularization. In this paper we clarify so...

In the conversion of fuel in the Tehran Research Reactor core from Highly- Enriched Uraniutn to Low-Enriched Uranium fuel neutronics analysis, thermal hydraulic calculations and kinetic performance of the core have to be studied. In this study, static and dynamic core performance for HEU and LEU fuels were investigated. In static conditions, two groups of neutron flux distributions in axia...