Russia restarts a reactor at the occupied Zaporizhzhia nuclear plant
The test Between 26 Oct 2026 and 25 Oct 2027, a reactor unit at the Zaporizhzhia nuclear power plant reaches criticality under Russian operation, as reported by the IAEA.
Not under way · Confidence: medium · Reviewed 25 Oct 2026 · Scores from 1 to 10
This page answers: What could happen, how it is scored, and who is exposed?
Using this page
- Read the two scores: Likelihood and Impact are kept apart.
- Check what is happening, each fact with its source.
- Use the calendar for the dates to watch.
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Impact is the average of the four parts, rounded, plus one point when Canada is directly hit on two or more channels, up to 10.
Two separate scales from 1 to 10. Strature never multiplies or merges them.
Why it matters
Russia's regulator has licensed two of the six Zaporizhzhia reactors, and Rosatom says it will restart the plant as soon as the opportunity arises. All six units were still in cold shutdown in the IAEA's report of 2 September 2026; the plant has one fragile power line, and it went 18 days without off-site power in August-September 2026. A restart needs a quiet front, which the talks planned for November may or may not bring.
Why Likelihood 3 Pushes: the licences, Likhachev's statement, about 5,000 staff in place, a pumping station under construction, talks in November.
Why Impact 5 Threshold case: one unit reaches criticality. Regional breadth, small direct money, long entrenchment of control, costly replacement for Ukraine.
The other facts on file (7)
- Rostekhnadzor issued 10-year operating licences for Units 1 and 2; licensing for Unit 6 ongoing; all facilities still hold SNRIU licences. [1] (20 Feb 2026)
- Licence conditions keep the reactors in cold shutdown until ultimate heat sink and off-site power guarantees are resolved and extra safety documents approved. [1] (20 Feb 2026)
- All units in cold shutdown; no plans for hot shutdown; no restart while safety remains in jeopardy (IAEA understanding). [1] (20 Feb 2026)
- Unit 2 licence reported 19 Feb 2026; Rosatom to file for Units 3-5 by end-2026; plant 5.7 GW; floating pumping station up to 80,000 m3/h under construction. [2] (19 Feb 2026)
- All six reactors remained in cold shutdown, 2 Jun-29 Aug 2026; the 20 Aug outage was the 26th loss of all off-site power since the war began; the Dniprovska 750 kV line, damaged 24 Mar 2026, was repaired in June but needs further grid repairs before reconnection; workforce about 5,000. [9] (29 Aug 2026)
- Likhachev: Russia will begin starting up and operating the station under IAEA supervision as soon as the opportunity arises; power could be supplied to Ukraine under certain conditions. [8] (13 Mar 2026)
- No unit has operated in generation mode since September 2022; Units 2 and 6 named as first restart candidates. [5] (4 Apr 2025)
Where it sits
How it spreads
Between 26 Oct 2026 and 25 Oct 2027, a reactor unit at the Zaporizhzhia nuclear power plant reaches criticality under Russian operation, as reported by the IAEA.
Not under wayChannels 5 on the card
- CanadaNo direct Canadian channel on file.
- Nuclear safetyA running reactor needs far more cooling water and stable power than one in cold shutdown [1][2]; a restart with one line and a pond heat sink would raise the stakes of every power cut [3][4].
- UkraineThe six units total 5.7 GW [2]; a restart under Russian licences would entrench Russian control of Ukraine's largest plant, which Ukraine and the IAEA Board's resolutions reject [1][4].
- Peace talksThe plant is a key issue in the talks; US proposals have included US management, per Reuters [8]; a restart before a deal would change the bargaining.
- Sanctions and rulesTests Western rules on Rosatom and on US-made fuel loaded in four units [6] (Strature reading; no sanctions step announced).
Sectors 1
- Energy and pipelines
Countries 4
- Ukraine primary
- Russia primary
- European Union
- United States
Who is exposed
- Countries
- Ukraine, Russia, European Union, United States
- Sectors
- Energy and pipelines
Three scenarios and their signposts
- S1
Cold shutdown holds
Fighting continues and the licence conditions are not met.
- S2
Ceasefire, then preparation
A ceasefire lets Rosatom restore lines and water and move a unit to hot shutdown, without criticality inside the window.
- S3
Restart
A truce on Russia's terms, or a decision to run despite the war, brings Unit 2 or 6 to criticality.
| Path | Signpost |
|---|---|
| S1 | A further loss of all off-site power reported by the IAEA |
| S2 | The IAEA reporting a unit in hot shutdown |
| S3 | A Rostekhnadzor approval of the extra safety documents |
No probability is given for the three paths.
Dates to watch
The dates to watch
A dot is a day, a bar a month or a year; a hollow mark is tentative. The line marks today.
- Nov 2026 Fourth round of Russia-Ukraine talks, probably Abu Dhabi [7] Tentative · Outside event
- Dec 2026 Rosatom target to file licence applications for Units 3-5 [2] Tentative · Outside event
- Dec 2027 Plant director's target for Russian licences for all units (after the outlook date) [5] Tentative · Outside event
Connected in Strature
- Russia
- European Union
- United States
- Russia and Ukraine sign a general ceasefire on the current front line Driven by: Rosatom ties a restart to the end of the military threat.
- Russia's war reaches NATO's eastern flank Driven by: The course of the war decides the plant's power and access.
- Russia halts enriched uranium shipments to the US before the US ban takes full effect Shares a channel: Rosatom's nuclear fuel business.
Sources
9 sources, numbered as the text cites them
- Nuclear Safety, Security and Safeguards in Ukraine, GOV/2026/7. IAEA Board of Governors · 25 Feb 2026 · International body · confidence high · retrieved 25 Oct 2026
- Russian regulator issues operating licence for second Zaporizhzhia unit. World Nuclear News · 19 Feb 2026 · Industry · confidence high · retrieved 25 Oct 2026
- Zaporizhzhia reconnected to external power after 18 days. World Nuclear News · 8 Sep 2026 · Industry · confidence high · retrieved 25 Oct 2026
- Russia burns occupied Zaporizhzhia nuclear plant's last-resort generators as everyday power, Ukraine says. Euromaidan Press · 7 Sep 2026 · News · confidence medium · retrieved 25 Oct 2026
- Zaporizhzhia restart timetable suggested, Ukraine rejects plan. World Nuclear News · 4 Apr 2025 · Industry · confidence high · retrieved 25 Oct 2026
- Zaporizhzhia security, restart and US fuel discussed in IAEA-Russian talks. World Nuclear News · 9 Jun 2025 · Industry · confidence high · retrieved 25 Oct 2026
- Ukraine and Russia eye new peace talks, but steep obstacles remain. AP via MPR News · 24 Oct 2026 · News · confidence high · retrieved 25 Oct 2026
- Russia says it could sell power to Kyiv from Zaporizhzhia nuclear plant. Reuters via Yahoo News · 13 Mar 2026 · News · confidence high · retrieved 25 Oct 2026
- Nuclear Safety, Security and Safeguards in Ukraine, GOV/2026/49. IAEA Board of Governors · 2 Sep 2026 · International body · confidence high · retrieved 26 Oct 2026
Reviewed 25 Oct 2026 · version 1 · last change: Likelihood 4 to 3 · All risks