Harrisburg Three Mile Island nuclear plant

Harrisburg, Three Mile Island NPP - darkometer rating : 6 - The site of the potentially worst nuclear power station accident before Chernobyl . The accident happened in 1979 at a power plant called Three Mile Island but it is better known under the name of the closest city, Harrisburg, which is in central Pennsylvania, USA . > More background info > What there is to see > Location > Access and costs > Time required > Combinations with other dark destinations > Combinations with non-dark destinations > Photos More background info: Unlike at Chernobyl in 1986, there were no casualties in the Harrisburg accident, but the chain of events at Harrisburg's Three Mile Island (TMI) plant (which takes its name from the fact that it's on an island in the river three miles south from the Middletown district of Harrisburg) got perilously close to a catastrophe that could have been on a similar scale – only in a much more densely populated area. The incident still stands as the worst civilian nuclear accident ever in the USA . Without going too much into the physics of it all, this is roughly what happened in March/early April 1979: pump failure and operation errors led to a breakdown of the cooling system which in turn led to an accumulation first of steam (instead of cooling water) and then of hydrogen in the upper parts of the reactor core. Thus exposed it came to a partial reactor core meltdown. Radiation levels went up so much that it could be detected even through the thick walls of the containment unit. What was worse, leaks of contaminated coolant reached the outside. How much radioactivity exactly was released in the end is, naturally, disputed … In any case, the area around the plant was partly evacuated – as the spectre of a real nuclear catastrophe loomed large in the north-east of the USA .