Computation of the fluence of fast neutrons in the reactor pressure vessel of Unit I of Kozloduy NPP Original Research Article

The procedure of computation of the fluence of fast neutrons in the pressure vessel of the WWER-440 reactor of Unit I of the Kozloduy NPP, Bulgaria, by the method of the discrete ordinates using the neutron transport code TORT and the cross-section library SAILOR is outlined. The principal results for cycles 16, 17 and 18 are reported, together with a comparison between measured weight specific activities of 54Mn (a product of the reaction 54Fe(n,p)54Mn) in shavings taken from different locations on the inner surface of weld no.4 of the pressure vessel of unit I after the end of cycles 17 and 18 and the corresponding predicted values on the basis of the computed fluence of fast neutrons at these locations.