Stranded Spent Fuel: 20 Shutdown US Sites Still Host 12,310 MTU with No Repository Path

When a US power reactor permanently shuts down, the electricity stops. The used fuel usually does not leave. Until the federal government opens a geologic repository — or an accepted consolidated interim storage facility that can actually take commercial canisters — that inventory stays on the former generating campus, increasingly in dry casks on an Independent Spent Fuel Storage Installation (ISFSI).

Pacific Northwest National Laboratory’s 2024 inventory report (PNNL-33938 Rev. 1.1), built from DOE’s GC-859 survey through 31 December 2022, labels these campuses Group A: every reactor on the site is permanently shutdown, and spent nuclear fuel (SNF) remains on site. That census counts 25 reactors on 20 sites holding about 12,310 metric tons of uranium (MTU) in 39,221 assemblies. Roughly 13.5% of the commercial light-water inventory still sitting at nuclear power reactor sites is already stranded at places that no longer make power.

The interactive dashboard above ranks those sites by remaining MTU, maps Census regions, splits license status (classic ISFSI-only versus active decommissioning with an onsite pad), plots years-since-shutdown against mass, and walks the cumulative cohort path as early retirements stack onto the 1990s wave.

What “stranded” means in this cut

Stranded here is an institutional label, not a physics claim. The fuel is cooled, packaged, and regulated. What is missing is an offsite acceptance path. The Nuclear Waste Policy Act still points toward a geologic repository; Yucca Mountain’s license process remains unfinished; private consolidated interim storage proposals have faced litigation and have not opened a commercial receiving lane. GAO’s spent-fuel oversight work keeps returning to the same structural fact: utilities (and their ratepayers / DOE judgments) finance onsite storage because the federal disposal system has not taken title and shipped the waste.

We therefore count Group A sites with remaining SNF — not every historical reactor that ever closed. Prototype and special cases (Fort St. Vrain’s HTGR fuel under a different custody story; TMI-2 debris) sit outside the LWR Group A MTU totals PNNL publishes. The dashboard’s site ladder is the commercial LWR stranded set as of the inventory date.

Twenty campuses, two storage postures

PNNL splits Group A by how the fuel is stored at year-end 2022:

A1 is the dominant story. Decommissioning programs move assemblies from spent-fuel pools into dry casks so the pool island can be dismantled. Once that transfer finishes, the site can look like an empty industrial parcel with a fenced pad of vertical or horizontal casks — sometimes under a slimmed ISFSI-only materials license after the Part 50 plant license is terminated.

A2 at the inventory date was a short list: Indian Point (New York) and Palisades (Michigan) still showed mixed wet-and-dry inventories while decommissioning (and, later, restart talk at Palisades) played out. Those campuses are still “shutdown-site stranded” in the Group A sense for end-2022 even if their next chapter differs from a Maine Yankee–style pad.

ISFSI-only licenses: the oldest stranded pads

The Energy Information Administration’s shutdown reactor table flags a stricter status: ISFSI Only — the generating plant is gone as a licensed reactor; what remains is a storage license. For commercial LWR campuses in that bucket (excluding Fort St. Vrain’s HTGR), the end-2022 inventory still shows fuel at Big Rock Point, Haddam Neck, Maine Yankee, Rancho Seco, Trojan, and Yankee Rowe. Those six pads hold about 1,729 MTU — a minority of Group A mass, but the clearest illustration of the policy failure: communities finished decommissioning decades ago and still host the canisters.

Maine Yankee alone accounts for roughly 542 MTU in 60 SNF casks. Trojan holds about 359 MTU; Haddam Neck about 414 MTU. These are not temporary construction laydown yards. Humboldt Bay’s 1976 shutdown and La Crosse’s 1987 exit show how long “temporary” onsite storage can run even when the license label differs.

Post-2000 early retirements thickened the pile

Pre-2000 A1 inventory is about 2,815 MTU. Post-2000 A1 dry inventory is larger — about 6,868 MTU — because the 2010s wave of economic and steam-generator–era retirements moved big BWR and PWR cores into dry storage quickly: Crystal River, Kewaunee, San Onofre, Vermont Yankee, Fort Calhoun, Oyster Creek, Pilgrim, Three Mile Island Unit 1, Duane Arnold, and peers.

San Onofre is the mass outlier among West Coast shutdowns at roughly 1,609 MTU and 123 SNF casks. Zion’s twin units leave about 1,019 MTU on the Illinois lakeshore. Northeast campuses such as Oyster Creek (~802 MTU), Pilgrim (~735 MTU), and Vermont Yankee (~706 MTU) show how coastal and riverine communities inherit pad security, emergency planning, and local tax-base fights long after megawatts disappear from the grid.

The cohort chart in the dashboard makes the compounding visible: each early retirement adds a step to cumulative stranded MTU. The slope steepens after 2013 even though classic ISFSI-only licenses were mostly locked in during the 1990s.

Geography is uneven — and politically sticky

Census-region totals (from the site table) concentrate stranded mass in the Northeast and West, with a substantial Midwest share and a thinner South footprint dominated by Crystal River. That pattern matters for consent-based siting debates: the communities already hosting shutdown-site ISFSIs are not randomly distributed, and they have spent years arguing that “temporary” storage without a federal offtake is a de facto national policy.

NRC’s decommissioning site finder tracks the active DECON and SAFSTOR dockets — San Onofre, Pilgrim, Indian Point, and others — alongside the quieter ISFSI-only pads. From a fuel-management perspective the distinction is thinner than the license paperwork suggests: both sets need secure dry storage, aging-management programs, and a destination that does not yet exist.

Caveats and what this cut is not

• Inventory date. Figures are end-2022 GC-859 / PNNL. Transfers after that date, further pool de-inventory, or restart pathways (notably Palisades discussions) can move a site between A1 and A2 or even out of Group A if operations resume.
• MTU vs. canisters vs. risk. Heavier MTU sites are not automatically “riskier.” Cask design, seismic setting, coastal exposure, and security posture differ. We chart mass and years stranded because they answer the stranded-count question; they are not a hazard ranking.
• ISFSI-only vs. DECON-with-ISFSI. EIA’s ISFSI Only flag is a license-status lens. Many A1 sites still carry broader decommissioning licenses while looking operationally like pads. We show both so readers can toggle the strict versus inclusive stranded set.
• No repository ≠ unsafe storage. Dry cask storage is an NRC-licensed activity with decades of operating experience. The policy failure is disposal and title transfer, not an implication that pads are failing today.
• Excluded inventories. DOE-managed research fuel, Morris away-from-reactor storage, reprocessed West Valley material, Fort St. Vrain HTGR, and TMI-2 debris are outside this LWR Group A campus total.

Why the count keeps rising until something opens

Every additional permanent shutdown without an offtake path adds a Group A site or thickens an existing pad. Operating fleets still hold the majority of US commercial SNF in pools and at-reactor ISFSIs, but the shutdown-site share is the politically sharp edge: neighbors see the plant disappear while the fuel remains, often under a thinner local tax base and a promise of temporary storage that has already lasted a generation.

Until a geologic repository or an actually receiving consolidated interim storage facility opens, the honest headline stays simple. Twenty all-shutdown campuses still host on the order of 12,310 MTU. Eighteen of them are already dry-only. Six classic ISFSI-only LWR licenses still babysit roughly 1,729 MTU of the oldest stranded commercial fuel — with nowhere federal to send it.

Sources and method

Site masses, cask counts, and Group A / A1 / A2 labels come from PNNL-33938 Rev. 1.1 Tables 2.1, 2.5, 2.7, and 2.8. ISFSI Only license labels follow EIA’s U.S. Nuclear Reactor Shutdown List. Decommissioning context is cross-checked against the NRC power-reactor decommissioning finder. Repository-path framing draws on GAO’s commercial spent-fuel management findings. Multi-unit campuses are collapsed to one site row (Indian Point, San Onofre, Zion). Years stranded measure last-unit shutdown through the end-2022 inventory date.