MOX fuel use in a BWR with extended power up-rate

Although MOX fuel coming from reprocessed depleted uranium fuels has been used as a recycling strategy by countries like France and Japan it is not a common policy in the 30 countries that uses nuclear power, nowadays it seems to be a more direct alternative to reduce the depleted fuel interim storage. Previously, the spent fuel pools of Laguna Verde Nuclear Power plant were redesigned to host the total operating life depleted fuel under its original nominal power condition, however the plant has been up-rated to 120% of its original nominal power increasing the number of depleted fuel forecasted. This new situation makes necessary the analysis of alternatives, being one of them recycling. The current paper assesses the viability of using MOX fuel in the up-rated Power Plant; the design of the boiling water reactor MOX fuel addresses the two main constraints of its use: shutdown margin and reactor stability. Fuel design proposed sets the appropriate MOX enrichment and the maximum MOX fuel batch reload that does not imply any modification to the reactor control systems to avoid an extra economical cost due to its use.

► Use of MOX fuel is assessed for a BWR under a extended power uprate (EPU).
► EPU conditions reduce the maximum amount of MOX fuel to be loaded.
► The use of MOX fuel affects mainly the core neutronics and not to the thermal hydraulics.
► Start up of an equilibrium mixed UO2–MOX core under EPU does not present stability problems.