THE FIRST COMPARISON OF THE SEVENTH AER DYNAMIC BENCHMARK PROBLEM RESULTS OBTAINED BY RELAP5-3D AND DYN3D/ATHLET COMPUTING CODES
22nd Symposium of AER on VVER Reactor Physics and Reactor Safety (2012, Průhonice, Czech Republic)
NEUTRON KINETICS AND REACTOR DYNAMICS METHODS
Abstract
The paper gives the first comparison of the 7th three-dimensional AER dynamic benchmark
calculation results received with the codes RELAP5-3D? (?JV) and DYN3D/ATHLET
(HZDR). This benchmark was defined by A. Kotsarev, M. Lizorkin and R. Petrin at the 20th
AER Symposium in Hanassari (Finland). It is focused on investigation of transient behavior
in a VVER-440 nuclear power plant. Its initiating event is the opening of the main isolation
valve and re-connection of the loop with its main circulation pump in operation. A water slug
with lower temperature of 100 oC enters the core which leads to a reactor power excursion.
The activation of the reactor scram is caused by the corresponding power level signal. As a
result of the scram, the turbines are turned-off by closure of the turbine isolation valves. All
main circulation pumps remain in operation. Each participant had to use its own developed
input plant data deck and parameterized library of macroscopic cross sections. The VVER440/213 plant is at the end of the first fuel cycle and in hot full power conditions. The initial
reactor power tuning and burnup calculations were performed with the code DYN3D by both
participants. The first part of paper contains a brief description of RELAP5-3D?and
DYN3D/ATHLET system codes, their NPP input decks and reactor core models. The second
part shows the comparison of important global and local time dependent parameters. The
trends of main calculated parameters are very close. The calculated nuclear and thermalhydraulic phenomena like reactor power, cold leg mass flow rates, cold and hot leg coolant
temperatures, upper plenum pressure, pressurizer water level and steam generator powers
agree quite well. The differences in the time behavior of compared parameters are discussed
at the end of paper.