Holtec International has unveiled a new "proto-prompt" decommissioning strategy, which the US company says could see the conversion of a nuclear power plant site to greenfield status within about five-and-a-half years after the plant is shut down.
|Holtec's heat dissipating fuel basket, made from Metamic HT (Image: Holtec)
Holtec said it was prompted to develop the strategy to address concerns about the risk of accidental pool drainage, with the associated risks of a zirconium fire. The company said such a scenario, while "non-credibly improbable, stalks the decision-making process of every nuclear plant owner preparing to draw down its workforce after ceasing operations".
When a reactor is shut down, its used nuclear fuel is usually 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.
Holtec's strategy relies on the use of its friction-stir welded fuel basket made of Metamic HT, an aluminium boron carbide metal matrix composite. The welds do not suffer from distortion typically seen with conventional welding process.
The basket 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, the company said.
The strategy will eliminate the fuel and high-level waste "as the obstacle to demolishing the plant" and allow a site to be restored more quickly, it added.
Holtec first announced development of its latest used fuel storage baskets in January 2014.
Researched and written
by World Nuclear News