engleski

Dose Rates Modeling of Pressurized Water Reactor Primary Loop Components with SCALE6.0

A 3D simulation model of typical pressurized water reactor primary loop components for effective dose rates calculation based on hybrid deterministic- stochastic methodology was created. Shielding calculations have been performed using MAVRIC shielding sequence of SCALE6.0 code package. A detailed model of a combinatorial geometry, materials and characteristics of a generic two loop PWR facility are based on best available input data. The sources of ionizing radiation in PWR primary loop components included neutrons and photons originating from critical core and photons from activated coolant in two primary loops. Detailed calculations of reactor pressure vessel and upper reactor head have been performed. The efficiency of particle transport for obtaining global Monte Carlo dose rates was further examined and quantified with flexible adjoint source positioning in phase-space. Shielding calculations were also performed for reduced PWR facility model which included reactor core and adjacent concrete structures with steam generator and pump. It was demonstrated that definition of air as a global adjoint source gave lower uncertainty of photon dose rates. Activation of primary loop coolant, which becomes additional gamma source in working reactor, was considered. The gamma dose rates were presented for brief and detailed MAVRIC calculations. Control and numerical parameters of the MAVRIC shielding sequence with hybrid methodology have been optimized for effective Monte Carlo deep penetration shielding calculation.

reactor model; Monte Carlo; hybrid methodology; SCALE6.0; dose rates; adjoint source; shielding; variance reduction

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