Neutron fluence, dosimetry and damage response determination in in-core/ex-core components of the venus CEN/SCK LWR using 3-D Monte Carlo simulations: NEA's VENUS-3 benchmark
Jm. Perlado et al., Neutron fluence, dosimetry and damage response determination in in-core/ex-core components of the venus CEN/SCK LWR using 3-D Monte Carlo simulations: NEA's VENUS-3 benchmark, NUCL TECH, 129(3), 2000, pp. 285-296
Validating state-of-the-art methods used to predict fluence exposure to rea
ctor pressure vessels (RPVs) has become an important issue in identifying t
he sources of uncertainty in the estimated RPV fluence for pressurized wate
r reactors. This is a very important aspect in evaluating irradiation damag
e leading to the hardening and embrittlement of such structural components.
One of the major benchmark experiments carried out to test three-dimension
al methodologies is the VENUS-3 Benchmark Experiment in which three-dimensi
onal Monte Carlo and S-n codes have proved more efficient than synthesis me
thods. At the Instituto de Fusion Nuclear (DENIM) at the Universidad Polite
cnica de Madrid, a detailed full three-dimensional model of the Venus Criti
cal Facility has been developed making use of the Monte Carlo transport cod
e MCNP4B. The problem geometry and source modeling are described, and resul
ts, including calculated versus experimental (C/E) ratios as well as additi
onal studies, are presented. Evidence was found that the great majority of
C/E values fell within the 10% tolerance and most within 5%. Tolerance limi
ts are discussed on the basis of evaluated data library and fission spectra
sensitivity, where a value ranging between 10 to 15% should be accepted. A
lso, a calculation of the atomic displacement rate has been carried out in
various locations throughout the reactor,finding that values of 0.0001 disp
lacements per atom in external components such as the core barrel are repre
sentative of this type of reactor during a 30-yr time span.