A proto-prompt decommissioning strategy devised by Florida-based Holtec International is intended to convert a nuclear power plant site to greenfield status within about five-and-a-half years after the plant is shut down.

A typical heat dissipater fuel basket made from Metamic HT. Source: Holtec InternationalA typical heat dissipater fuel basket made from Metamic HT. Source: Holtec InternationalAfter reactor shutdown, used nuclear fuel is typically stored in an at-reactor pool for several years to allow it to cool sufficiently to be transferred to another suitable long-term storage facility or for disposal.

To shorten the storage interval and address concerns about the risk of accidental pool drainage, with the associated risks of a zirconium fire, Holtec proposes rapid de-fueling by use of its friction-stir welded Metamic HT fuel basket.

The basket is composed of an aluminum boron carbide metal matrix composite, and its welds do not suffer from distortion typically seen with conventional welding process.

The Metamic HT has over ten times the thermal conductivity of conventional stainless steel fuel baskets, which shortens the required cooling period of used fuel, prior to transfer to dry storage, from about seven years to two-and-a-half years. This would enable a shuttered plant site to be returned to its pre-plant state within about 66 months after the reactor's shutdown.

To contact the author of this article, email engineering360editors@globalspec.com