SYMPOSIA PAPER Published: 01 January 2001

New NEA Benchmarks for Calculating Fast Neutron Fluence in the Reactor Pressure Vessel


For proving the precision achievable today in predicting the neutron fluence for reactor pressure vessels, the OECD/NEA initiated a new international benchmark exercise as a blind test, where the measured results are not known in advance. To validate two- and three-dimensional radiation transport codes, high precision measurements at the VENUS critical facility of SCK.CEN, Mol in Belgium were used representing the pressure vessel internals of a Westinghouse three loop reactor. About 20 independent calculations were contributed world-wide for the two-dimensional benchmark VENUS-1. The most challenging task was the validation of the newest versions of three-dimensional transport codes like TORT, PENTRAN and MCNP. 14 calculations were contributed for the complex 3D-benchmark VENUS-3 and compared with about 400 local measurements. In conclusion, the results of the three-dimensional benchmark VENUS-3 were in general much closer to the experimental values than for the two-dimensional benchmark VENUS-1, which shows inherent deficiencies of two-dimensional transport calculations that suffer on approximations like diffusion based axial buckling or improper averaging of axial sources and shielding layers.

Author Information

Hehn, G
, Amorbach, Germany
Na, BC
OECD Nuclear Energy Agency, Issy-les-Moulineaux, France
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Developed by Committee: E10
Pages: 303–311
DOI: 10.1520/STP13610S
ISBN-EB: 978-0-8031-5450-6
ISBN-13: 978-0-8031-2884-2