Southern California Edison is dismantling San Onofre Units 2 and 3 (and finishing Unit 1) under the DECON method, with all spent fuel already in on-site dry storage since 2020. As of November 2025, 47 of 62 site structures had been demolished and SCE planned to start removing the twin containment domes in late 2026.
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Current state
| Status | Active dismantling |
| Country | United States |
| Location | San Clemente, California |
| Site | San Onofre Nuclear Generating Station |
| Units | Unit 1, Unit 2, Unit 3 |
| Unit count | 3 |
| Reactor types | PWR |
| Owner / licensee | Southern California Edison |
| Decommissioning contractor | SONGS Decommissioning Solutions (EnergySolutions/AECOM JV) |
| Strategy | Immediate dismantling |
| Final shutdown | 2013-06 |
| Decommissioning start | 2020 |
| Target completion | 2028 |
| Cost estimate | USD 4.41bn (as of 2026-03) |
| Spent fuel | All spent fuel transferred to the on-site ISFSI (Holtec UMAX / NUHOMS) by August 2020; NRC lists ISFSI closure in 2051 pending DOE pickup. |
| Notable issue | 2018 cask-loading misalignment incident triggered NRC special inspection; spent fuel stranded on a seaside bluff pending federal disposal. |
Notes
NRC estimated closure: 2028 for unrestricted-use demonstration, ISFSI 2051; NRC says Unit 1 closure 2032. Cost: CPUC-approved $4.41bn per WNA (page updated 2026-03); NBC 7 (Dec 2025) cites a $4.7bn project. Trust fund about $3.37bn per WNA but no as-of date, so not recorded.
Timeline
- 2013-06-07 — SCE announced the permanent retirement of Units 2 and 3 after replacement steam generator failures. (source)
- 2018-01 — Transfer of spent fuel from wet to dry storage began. (source)
- 2020-08 — All spent fuel was placed in dry storage and the site moved to an ISFSI-only license. (source)
- 2021-03 — Building demolition began; 26 structures were demolished by year end. (source)
- 2025-11-06 — SCE reported 47 of 62 site structures demolished and preparations to remove the containment domes starting in late 2026. (source)
- 2026-08-18 — SCE announced a Community Engagement Panel meeting with the US DOE on offsite disposition of the stored used fuel. (source)
The timeline is append-only: corrections are added as new entries. Stated targets appear in the current-state table, never as milestones.
Related sites
- Biblis Nuclear Power Plant (Units A and B) Active dismantling · Germany
- Brokdorf Nuclear Power Plant (KBR) Active dismantling · Germany
- Brunsbüttel Nuclear Power Plant (KKB) Active dismantling · Germany
- Chinshan Nuclear Power Plant Fuel removal · Taiwan
- Chooz A Active dismantling · France
- Crystal River Unit 3 Site restoration · United States
- Doel Nuclear Power Plant (Units 1-3) Shut down · Belgium
- Dounreay (DFR and PFR fast reactors) Active dismantling · United Kingdom
See all 72 sites in the Nuclear Decommissioning Tracker →
Sources
- San Onofre - Units 2 and 3 — U.S. NRC (primary), checked 2026-10-11
- SONGS Decommissioning Timeline — Southern California Edison (primary), checked 2026-10-11
- SONGS Dismantlement Update to be presented ... Nov. 13 Community Engagement Panel Meeting — Southern California Edison (primary), checked 2026-10-11
- Demolition of Iconic Containment Domes at San Onofre to Start Next Year — NBC 7 San Diego, checked 2026-10-11
- Offsite Disposition of Used Nuclear Fuel Among Topics DOE to Address at SONGS CEP Meeting — Southern California Edison (primary), checked 2026-10-11
- Decommissioning Nuclear Facilities — World Nuclear Association, checked 2026-10-11
- Locations of Power Reactor Sites Undergoing Decommissioning — U.S. NRC (primary), checked 2026-10-11