Forsmark
포르스마르크
A nuclear power plant on Sweden's east coast that, on 28 April 1986, became the first facility outside the Soviet Union to detect radioactive fallout from the Chernobyl disaster. Radioactive particles on a worker's clothing triggered the plant's portal monitors; Swedish authorities traced the contamination to its Soviet source through wind-trajectory analysis. The detection at Forsmark forced the Soviet government, after two days of silence, to publicly acknowledge the accident.
In depth
Background
Forsmark Nuclear Power Plant sits on Sweden's Baltic coast in Östhammar Municipality, about 100 km north of Stockholm. It operates three boiling water reactors and has supplied roughly 14% of Sweden's electricity since entering commercial service in December 1980.
The Chernobyl Detection (28 April 1986)
On the morning of Monday, 28 April 1986, chemist Cliff Robinson passed through a portal radiation monitor at the Forsmark plant and triggered an alarm. He had not been inside the controlled area, which made the alert deeply puzzling. Within minutes, other workers also set off the detector, and Robinson took a shoe from one of them for gamma spectroscopy. The germanium detector revealed a spectrum of radioactive elements never seen in Forsmark's routine cooling-water samples, ruling out a plant leak.
The station was partly evacuated, but the Swedish Radiation Safety Authority (SSI) quickly established that the source was external. The Swedish National Defence Research Institute (FOA) and the Meteorological and Hydrological Institute (SMHI) ran backward air-parcel trajectories, which pointed to Lithuania, Belarus, and Ukraine. Suspicion fell first on the Ignalina plant in Lithuania before narrowing to Chernobyl.
Forcing Soviet Acknowledgment
That day Swedish diplomats asked Moscow whether a nuclear accident had occurred on Soviet territory; the Soviets denied it. Only when Sweden announced it would file an official alert with the International Atomic Energy Agency (IAEA) did the Soviet Union admit the Chernobyl disaster. The detection at Forsmark was the turning point that broke two days of Soviet silence.
Sources
- IAEA Bulletin, Autumn 1986: "Monitoring the fallout" by Mikael Jensen & John-Christer Lindhe, SSI
- Sveriges Radio, 22 April 2011: "25 years after Chernobyl, how Sweden found out", interview with Cliff Robinson
Sources
- Wikipedia (EN) The radiation monitors at Forsmark were the first outside the Soviet Union to detect Chernobyl fallout, forcing Soviet acknowledgment after two days of cover-up.
- Wikipedia (EN) On the morning of 28 April, radiation levels set off alarms at Forsmark; Swedish government contacted Soviet government that day, leading to the Soviet admission.
- iaea.org IAEA Bulletin (Autumn 1986): first detection at Forsmark on 28 April when morning shift personnel triggered portal monitors; backward trajectories pointed to Ukraine/Belarus/Lithuania region.
- sverigesradio.se Sveriges Radio (2011): first-person account by chemist Cliff Robinson, who triggered the Forsmark alarm; Sweden warned it would file an IAEA alert, after which the USSR admitted the accident.