A US federal watchdog has called on Congress to consider amending a key nuclear waste statute and to set up an independent board in an effort to overcome an impasse over what to do with the nation’s growing inventory of spent nuclear fuel.

The Government Accountability Office said in a report there are about 86,000 tonnes of spent nuclear fuel from commercial reactors stored at 75 US sites and this amount continues to grow.

Policymakers have been at an impasse over what to do with the spent fuel since the licensing of the Yucca Mountain repository stopped in 2010. Unable to meet its disposal commitment, the US government has paid reactor owners about $9bn for storage.