Upflow conversion - Eliminating the potential for baffle jetting at McGuire

Fuel failures indicative of baffle jetting were observed at Duke Power Company's McGuire units 1 and 2 in 1986 and 1987, respectively. In September 1990 the lower rector internals of unit 2 were modified to permanently eliminate the potential for baffle jetting. The unit 1 internals are to be converted in 1991. McGuire nuclear station is a two-unit, four-loop, Westinghouse pressurized water reactor with 17 by 17 fuel and a gross electrical output of 1,130 MW (electric) per unit. The modification performed on the unit 2 reactor internals resulted in a reversal in the direction of flow through the core barrel and baffle region. This flow reversal reduces the pressure drop across the baffle plates, thus eliminating the driving force for the baffle jets. This modification consists of plugging existing holes in the core barrel and opening new holes in the top former plate to change the flow direction