Fuel assembly incident pauses Palisades loading

Holtec International has paused fuel loading at the Palisades Nuclear Power Plant in Michigan after a previously used fuel assembly tilted inside the reactor vessel, interrupting a restart sequence that began in August. Engineers are developing equipment to retrieve the assembly, and Holtec is preparing a license amendment request for the Nuclear Regulatory Commission (NRC); progression to later startup modes depends on resolving the event.

Key facts

• Fuel loading began on August 30, 2026, when Palisades entered Mode 6, or Refueling.
• One previously used fuel assembly tilted after it was placed in the vessel; Holtec says the fuel-handling machine grapple had been disengaged.
• Holtec says fuel loading remains paused while retrieval equipment is developed.
• The plant was reconnected to its 345-kilovolt switchyard on September 11, 2026, though commissioning and testing continue.

What happened

Palisades began loading fuel into its reactor vessel on August 30, entering Mode 6, the refueling condition in which crews handle fuel while the reactor is shut down. During that work, one assembly tilted from its upright position after it had been placed, according to Holtec's September 21 progress report. The company says the fuel-handling machine's grapple had already been disengaged.

Holtec says plant personnel responded under established procedures and notified the NRC. The company evaluated the event and concluded that it did not trigger NRC safety-reporting requirements. That is the operator's account of the reporting threshold, not an NRC public finding on the event's cause or significance. The NRC's Palisades facility page tracks licensing and oversight material for the plant.

A root-cause evaluation is underway. Holtec says its corporate engineering team has devised and is developing equipment to retrieve the assembly and return it to the spent-fuel pool. The operator is also preparing a license amendment request describing the proposed retrieval method. It has not announced a date for submitting that request, receiving NRC action or resuming fuel loading.

The pause is limited to the fuel-loading work, according to Holtec. Other restart activities that do not depend on resolving the assembly issue continue, including plant testing, restoration and modifications. But that parallel work does not remove the constraint: Holtec says movement into subsequent operating modes depends on satisfactory resolution of the assembly issue, completion of required testing and modifications, and applicable NRC approvals.

Why it matters

Fuel loading sits on the critical path between mechanical restoration and reactor startup. The event does not, by itself, establish a broader safety problem or a change to the plant's license. It does add engineering and regulatory work before loading can proceed and before Palisades can advance to the next operating mode.

That distinction matters because a restart is a sequence of gated steps, not a single switch-on. Holtec's account says teams are still verifying that cooling, electrical, protection and other systems can perform as designed. After fuel loading is complete and the reactor vessel is reassembled, the company expects to prepare for Mode 5, or Cold Shutdown, before further progression. The operator has not given a new commercial-operation date in its update.

The public information so far is narrow. Holtec has described the assembly's tilt, the disengaged grapple, the planned retrieval and its reporting-threshold assessment. It has not provided a detailed account of the physical cause, the assembly's condition, or the equipment design. Those details will help explain the recovery plan, but should not be inferred from the fact that loading has stopped.

Background

Palisades, a single-unit plant in Covert Township, last operated in 2022 before Holtec pursued a restart. Earlier this month, NNN reported that fuel loading had begun at Palisades; the new incident is a material development in that same sequence, rather than evidence that the plant had reached power operation. Related restart oversight includes the NRC's radiation-safety findings at Palisades, which concerned separate worker-protection issues and should not be conflated with the fuel-handling event.

Fuel loading began with a core planned to contain 204 assemblies, including new and partially used fuel, according to Holtec's August restart update. Holtec's newer report does not say how many assemblies had been loaded when the tilt occurred. Without that count, the remaining loading work and its duration cannot be estimated from the public record.

The plant also reached a separate electrical-restoration milestone during the same period. Holtec says Palisades reconnected to the 345-kilovolt switchyard on September 11, following restoration work coordinated with ITC, the transmission operator. Final commissioning and tests continued after the connection. The switchyard milestone is useful context for restart readiness, but it does not allow the reactor to move forward while the assembly issue remains unresolved.

What's next

The next public milestones are Holtec's license amendment request, any NRC review or approval tied to retrieval, the actual recovery of the assembly, and a restart of fuel loading. Holtec has said that subsequent operating modes also require successful testing and modifications and applicable NRC approvals. No resumption date or revised startup timetable was included in its September 21 update.

For now, the status is specific: fuel loading is paused, recovery equipment is being developed, and unrelated restart work is continuing. A firmer schedule will depend on the approved retrieval approach and the time required to complete loading and the remaining startup checks.