'MIDICORE' VVER-1000 core periphery power tilt benchmark proposal
20th Symposium of AER on VVER Reactor Physics and Reactor Safety (2010, Hanasaari, Espoo, Finland)
Reactor physics experiment and code validation
Abstract
The MIDICORE benchmark is a 2D calculation benchmark based on the VVER-1000 reactor
core cold state geometry with taking into the account the geometry of explicit radial reflector.
The main task of this benchmark is to test the pin by pin power distribution in selected fuel
assemblies that are placed mainly at the border of the VVER-1000 core. This is due to an
observed phenomenon at calculation of the ?first core loading? (completely composed from
TVEL TVSA-T fresh fuel assemblies 1) at Temelin NPP (VVER-1000 core), where the
maximum of fuel pin power (FdH) was found in a peripheral FA in a fuel pin at assembly edge
in direction to the core centre. This phenomenon consist not only in position where this
maximum occurs, but especially in relatively big difference of FdH value observed when this
value was determined by codes based on pin to pin diffusion difference method on one side
and by codes based on nodal diffusion method with pin power reconstruction on the other
side. Because value of FdH is not directly measured by the core monitoring system, a decision
about a proposal of benchmark of this kind has been made. In this contribution we define the
MIDICORE benchmark; we present the preliminary reference Monte Carlo calculation results
and also preliminary MOBY-DICK macrocode calculation results.