On the Lake Michigan shore, a 204-assembly fuel load began at a reactor emptied for scrapping four years ago, and a single tilted bundle halted the comeback
The reactor vessel had been sitting empty for four years.
Every fuel bundle had been pulled out and stored when the Lake Michigan plant was headed for permanent closure.
On August 30, a crew reversed that sentence, beginning what engineers call Mode 6 refueling.
Whether one tilted bundle pushes that date depends on how quickly engineers can build and qualify a retrieval tool and how fast the NRC processes the amendment.
No American reactor had ever come all the way back from full defueling for decommissioning.
Then one assembly tilted, and the whole choreography stopped. What does a leaning bundle actually do to a core built for strict geometry?
What the tilted bundle actually means inside the vessel
The reactor core’s design is precise to fractions of an inch. Every one of the 204 slots is positioned so that control rods and coolant flow pass through at calculated angles, and a leaning assembly disrupts both. A tilted bundle is not a minor cosmetic problem; it is a geometric one with cascading consequences for the restart checklist.
During fuel loading, one previously used fuel assembly tilted from its upright position after it had been placed in the vessel, and the fuel handling machine grapple was already disengaged at that point. In plain terms, the overhead crane had let go when the bundle leaned, leaving nothing to hold it straight.
Alan Blind, a former engineering director at the plant, told a local news outlet that a tilting assembly is extremely rare. “In my 40-year career, I never experienced anything like that,” Blind said. Plant personnel responded in accordance with established procedures, the NRC was notified, and fuel loading remains stopped while engineers design the specialized equipment needed to recover the assembly.
A vessel on Lake Michigan that was never meant to open again
The plant began lowering fuel bundles back into a reactor that had been sitting empty since 2022. The milestone was real and measurable: the vessel, sealed for years, was open again, and the first assembly went in on the morning of August 30 under the reactor’s formal refueling protocol.
The reactor core consists of 204 fuel assemblies mixing new and partially used fuel from the plant’s most recent operating cycles. Sixty-eight brand-new assemblies had been staged in the spent fuel pool building since October 2025, and the rest are older bundles, some the same fuel pulled when the plant originally closed.
The 12-foot-tall assemblies, each containing 216 individual fuel rods, travel underwater the entire time they are moved. The pool above the open vessel is flooded, and the crane operator lowers each bundle through roughly 23 feet of water before it seats in its numbered slot. When the grapple releases and a bundle leans rather than stands, the problem unfolds entirely underwater, confirmed only by instruments and camera feeds.
The September 11 milestone that kept the timeline alive
On September 11, 2026, the plant reconnected to the 345-kV switchyard following extensive restoration work coordinated with the operator of the high voltage transmission system serving the site. That reconnection, detailed in the operator’s progress report, confirmed the restart program had not frozen entirely despite the vessel problem.
The 345-kV connection is effectively the plant’s on-ramp to the grid. Without it, a completed fuel load and a critical reactor would still have nowhere to send electrons.
Getting the switchyard back while the vessel problem is being solved meant engineers could work two challenges in parallel. Final commissioning and testing activities are continuing, and the operator says it remains focused on returning the plant to safe and reliable operation once all restart work is complete and applicable federal requirements are met. For context on how the NRC handles restart violations, a 2025 incident at a Texas reactor showed how regulators classify findings and what triggers a formal public hearing versus a written corrective action.
The complication that has no precedent to borrow from
A root cause evaluation was initiated to determine what caused the tilt and identify corrective actions. Engineers are developing equipment to retrieve the fuel assembly and return it to the spent fuel pool, and a license amendment request to the NRC is also required before retrieval can begin, because the operation falls outside the plant’s existing approvals.
Until that approval arrives, the fuel handling pause prevents advancement to Mode 5 cold shutdown, the next step between an open vessel and a reactor that can produce power. Previous reports indicate the operator is contracted to start supplying power by March 2027, meaning the calendar pressure is real.
Whether one tilted bundle pushes that date depends on how quickly engineers can build and qualify a retrieval tool and how fast the NRC processes the amendment. At least two other closed American reactors have been linked to potential restart discussions, so the industry is watching this entire sequence as a proof of concept.
What the road still looks like from here
The NRC confirmed there was no radiological release and no workers or members of the public were affected. The tilted bundle is a procedural and engineering problem, not a contamination event, and the regulatory review underway is aimed at understanding the mechanism rather than responding to a release concern.
After the leaning assembly is recovered and the rest of the fuel goes in, the vessel gets bolted shut and the plant moves to cold shutdown. Testing and NRC sign-offs stack up beyond that, and each step carries calendar risk when a delivery contract deadline is already on the board.
For a closer look at relay failures inside reactor systems and how they compound, the story of an undersized rotor hiding inside eleven failures over three years shows why root cause rigor matters as much as speed. At this Lake Michigan plant, the goal remains the one that stood on August 30: 204 assemblies seated, a vessel closed, and power flowing through a freshly restored switchyard.
Hugo is an engineer with strong technical expertise. Multilingual from an early age, his writing combines technical clarity with a strong interest in science and energy.
