IDAHO FALLS, IdahoEM’s spent nuclear fuel program at DOE’s Idaho National Laboratory (INL) Site recently determined that fuel canisters identified as high risk continue to be safely stored in five underground vaults following inspections to characterize the integrity of the fuel packages.

No water was present, hydrogen levels remain acceptable, and minimal fuel canister degradation due to corrosion was observed in the inspections inside the vaults at the Idaho Nuclear Engineering and Technology Center (INTEC).

“The results were very encouraging,” said Robert Gentry, the INTEC nuclear operations director for Fluor Idaho, EM’s cleanup contractor at the INL Site. “Our teams were able to gain valuable video information that showed the integrity of the vaults and fuel canisters remains satisfactory.”

A shield plug is removed to gain access to a Peach Bottom spent nuclear fuel basket.
A shield plug is removed to gain access to a Peach Bottom spent nuclear fuel basket.

The fuel canisters were shipped from Pennsylvania to the INL Site following the closure of the Peach Bottom Atomic Power Station, Unit 1 in 1974. Due to concerns of corrosion to fuel canisters in long-term pool storage, the canisters were placed in underground carbon-steel vaults at INTEC.

During the inspection, a mobile boom crane was used to lift the fuel baskets up to 12 inches, allowing a remote camera to capture video footage of the bottom of the baskets. Inspectors also obtained video footage of the fuel package tops and accessible surfaces, along with the interior surfaces of the vaults.

Gentry said long-term plans call for moving all Peach Bottom spent nuclear fuel canisters to new vaults that have welded, drainable steel-plate bottoms unlike the grouted bottoms of the current vaults. The steel plates prevent fuel packages from being in contact with pooled water, thereby mitigating elevated hydrogen concentrations and corrosion concerns. The new vaults are lined with steel and have purge and water removal capabilities.