## Validation of Three-Dimensional Synthesis RPV Neutron Fluence Calculations Using VVER-1000 Ex-Vessel Reference Dosimetry Results

According to Russian federal norms and the safety guide of the nuclear regulatory body of Russia, the maximum fast neutron fluence above 0.5 MeV at critical positions of the reactor pressure vessel (RPV) of VVER-type reactors is used for prediction of the RPV lifetime. For the computation of neutron fluences in the RPV near the reactor core midplane level, the three-dimensional (3-D) synthesis method based on two- and one-dimensional S{sub N} calculations may be acceptable but needs validation. The present validation analysis was carried out on the basis of neutron transport calculations for a VVER-1000 model by means of themore »