NRC allows alternate approach to removing tilted fuel assembly at Palisades

Roughly two weeks after Holtec submitted a license amendment request (LAR) following a fuel loading incident at the Palisades nuclear power plant, the Nuclear Regulatory Commission approved Holtec's emergency request to remove a tilted fuel assembly from the power plant's reactor vessel using custom-made equipment.

According to the NRC, the amendment was issued under exigent (or urgent) circumstances, as the incident has stalled fuel loading and some of the restart work at the Covert, Mich., plant. Holtec submitted the LAR on September 30, requesting approval by October 2. The public comment period on the matter expired on October 8.

The amendment revises Holtec's updated final safety analysis report (UFSAR) on Palisades, granting one-time permission to remove the fuel assembly from the reactor vessel and transport it to the spent fuel pool using an alternative method. In its decision, the NRC said its review confirmed Holtec's proposal can be carried out safely and in compliance with agency requirements.

Retrieving the fuel assembly: According to the LAR, the fuel assembly was placed in core location H-1, but it tilted over during fuel loading after being released by the refueling machine. The fuel assembly is tilted at a 30-degree angle from the core plate, with the lower tie plate in its core location and the upper tie plate leaning against the core shroud on the opposite side of the core. The fuel rods in the assembly have maintained their integrity, and none of the other fuel assemblies were impacted.

Workers will undertake an alternative fuel-handling process to retrieve the assembly. A containment polar crane and custom fuel movement device will transfer the fuel assembly out of the reactor. The plant team designed a custom fuel movement device to reduce risk while moving the assembly within the reactor cavity. The fuel assembly will stay a minimum of 10 feet underwater while it is lifted and transferred into a fuel transfer canister; the assembled and loaded canister will weigh 49,000 pounds. Once the canister and fuel assembly are secured, the crane will lift the canister out of the water. The canister then will be drained and moved to the equipment hatch station. There, an equipment hatch trolley will transport it to the spent fuel pool. A fuel pool building crane will lift the canister and place it vertically in the cask laydown area of the spent fuel pool.

According to documents, the LAR is effective immediately and will be implemented within 10 days of its October 13 issuance.