This paper presents a methodology to assess the effects of crud surface roughnesses on the normal operation of a PWR reactor.
A CFD methodology based on the use of RANS models and the implementation of roughness embedded in STAR-CCM+ CFD code has been developed and applied.
A typical PWR reactor case is investigated in details.
Results show how the presence of crudded rough rods induces a modification of the flow distribution as compared to the ideal case with clean smooth rods.
Notably, these modifications reflect a reduction of the mass flow rate, which in turn has a deteriorating consequence on the efficiency of the fuel-to-coolant heat transfer.