Obninsk Nuclear Power Plant
Obninsk becomes the first nuclear power station connected to an electrical grid
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Original prompt & settings (JSON) ↗The article filed under this date describes a Pennsylvania plant that started up in 1957. The event belongs to a Soviet reactor whose name meant "Peaceful Atom."
27 June 1954: five megawatts into the Moscow grid
On 27 June 1954, operators connected the Obninsk nuclear power station to the Moscow electrical grid, making it the first nuclear power station anywhere to supply electricity to a grid. The station stood about 100 kilometres southwest of Moscow.
It entered trial operation on its AM-1 reactor — a water-cooled, graphite-moderated channel reactor whose Russian designation meant "Peaceful Atom." Nikolai Dollezhal led its design; Dmitry Blokhintsev directed the scientific work at the Obninsk laboratory.
The generator delivered about five megawatts of electricity to the regional system, from a reactor rated at 30 MW thermal.
First, with a definition attached
The reactor had already reached criticality on 6 May, and "opening" is a loose word for what happened in June: the documented milestone is the first grid connection and entry into trial operation.
EBR-I in Idaho had produced usable electricity from fission in December 1951, initially powering four 200-watt bulbs, but it did not supply a public grid.
Obninsk was small and experimental. Britain's Calder Hall, opened in 1956, is generally identified as the first full-scale commercial nuclear power station.
The wrong plant on the wrong continent
The article carried under this listing describes Shippingport Atomic Power Station in Pennsylvania — a different plant, country, reactor, cast of participants and operating date. Shippingport began generating in December 1957.
That substitution leaves the actual 1954 event unwritten: the connection of Obninsk's AM-1 generator to the Moscow grid.
Its Shippingport details are also imprecise, saying the plant was "decommissioned in 1982" when it stopped producing power in October 1982 and the site was released for unrestricted use only in 1989.
Sources
Researched 24 Aug 2026 10 sources not yet audited Date corrected
How this was checked
Researched from the web into a fact sheet and rewritten from that sheet. This article has not yet had an independent model audit. How the pipeline works →
Date corrected. The research places this at 1954-06-27.
What the sources leave uncertain
- Sources often call June 27 the station's “opening,” but the precisely documented milestone is its first grid connection and entry into trial operation. The reactor had already reached criticality in May; formal commercial-operation databases use a later 1954 date.
- “World's first atomic power station” depends on definition. EBR-I in Idaho generated usable nuclear electricity in 1951, but it did not supply a public grid. Obninsk was the first nuclear power plant connected to a grid.
- Obninsk was small and experimental. Britain's Calder Hall, opened in 1956, is generally identified as the first full-scale commercial nuclear power station.
Checked against
- A pioneer of nuclear power: Obninsk's thirtieth anniversary, IAEA Bulletin
- IAEA Country Nuclear Power Profile: Russia
- APS-1 Obninsk reactor database entry, World Nuclear Association
- Outline History of Nuclear Energy, World Nuclear Association
- History of the Obninsk Nuclear Power Plant, Rosatom history project
- First Nuclear Power Plant, Institute of Physics and Power Engineering
- Nine Notable Facts About EBR-I, U.S. Department of Energy
- Calder Hall nuclear-history timeline, UK Nuclear Decommissioning Authority
- and 2 more