Pressure Vessel Fluence Calculations for the Hungarian VVER-440 Units for the Power Uprate and the Llifetime Extension
1 Hungarian Academy of Sciences, Centre for Energy Research, P.O.B. 49, 1525 Budapest 114, Hungary
2 Institute of Nuclear Techniques, Budapest University of Technology and Economics, Müegyetem rkp.3-9. 1111 Budapest, Hungary
Published online: 3 February 2016
A major project was launched at Paks NPP, Hungary, to investigate the possibility of lifetime extension up to 60 years. At the same time, new fuel types with higher enrichment and containing pins with gadolinium have been introduced. Due to these plans, the radiation load of the pressure vessel was evaluated up to 60 years irradiation, taking into account the past and planned future cycles. The computational procedure, elaborated and validated earlier for the fast flux calculation in the pressure vessel was modified for the new fuel types. The neutron source at the core boundaries was taken from core design calculations and the neutron transport from the source to and through the pressure vessel was followed by Monte Carlo calculations. A number of calculations were performed to adequately follow the change of the neutron source. The paper details this procedure, the used Monte Carlo model, the influence of the different reloading schemes on the radiation load and the calculated results.
© Owned by the authors, published by EDP Sciences, 2016
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