Validation of the New Apros Neutronics Model Against Measured VVER-1000 Data
25th Symposium of AER on VVER Reactor Physics and Reactor Safety (2015, Balatongyörök, Hungary)
Reactor physics experiments and code validation (benchmarks)
Abstract
The Apros simulation environment has currently two different three-dimensional neutronics
models available for use. The original model is based on the method of finite-differences and
has been a part of Apros since the beginning. A new neutronics model based on advanced
nodal codes HEXTRAN and HEXBU-3D has been under implementation since 2008. The
implementation of the model is now practically complete, but some small improvements and
validation calculations still remain to be done. This work concentrates on the validation part
of the new neutronics model. For the purpose of validation, the calculated results were
compared against measured data of a MCP coast-down transient performed at the Kozloduy
NPP in 1991-1992. The fact that no validation calculations against measured VVER-1000
data have yet been made with the new Apros neutronics model makes the transient case be
very convenient for the purpose of this work. In addition, the same transient has been
calculated by HEXTRAN as a part of an international code benchmark. It is convenient to be
able to compare these results with Apros. Comparisons are made with the results calculated
by the finite-difference model of Apros as well. This work presents the main results obtained
in the comparisons and makes conclusions based on them.