Analysis of conventional and plutonium recycle unit-assemblies for the Yankee (Rowe) PWR

Abstract

An analysis and comparison of Unit Conventional UO2 Fuel-Assemblies and proposed Plutonium Recycle Fuel Assemblies for the Yankee (Rowe) Reactor has been made. The influence of spectral effects, at the watergaps -and spectral-and transport effects at the UO2 - Mixed Oxide interface, on the powerpeaking has been determined. Two one thermal group methods have been developed for the calculation of powerpeaking in the two dimensional assemblies. The accuracy of the LEOPARD code and LASER code (thermal cut off 1.855 ev) for the calculation of the powerpeaking in conventional and plutonium recycle assemblies has been evaluated. The power distribution and local power peaking factors during burnup, including spectral effects, were also calculated with a macroscopic depletion model. Power gradients inside the peak UO2 rod and peak mixed oxide rod were also determined, and the variations in the heat flux, at the pellet and cladding surface, around these peak pins were calculated. Finally preliminary comparisons of engineering factors for the peak U02 rod and the peak mixed oxide rod have been made.