Burning of Plutonium in Advanced Modular Pebble Bed Htrs: The Most Effective and Safe Way for Disposition

The consumption of reactor-grade and weapons-grade plutonium in a high temperature pebble bed reactor with a power of 350 MWt (PB-HTR-350) is described. It is shown that high temperature pebble bed reactors can be highly effective burners of plutonium. The study shows how pebble bed HTRs, operating with a Pu/Th or U/Pu fuel cycle using the two ball-type concept can provide a simple way of achieving very effective destruction of plutonium. With an initial loading of 3g of plutonium in each feed ball, one can achieve almost complete destruction of the Pu-239 and a substantial reduction in the total amount of plutonium (reduction to 5% of the amount loaded). This is possible because the plutonium and thorium (or uranium) can be inserted into different types of balls and each type of ball can be circulated through the reactor a different number of times to achieve the desired burnup.