The Three Mile Island nuclear accident 40 years ago

The cooling towers at Three Mile Island nuclear plant
The cooling towers at Three Mile Island nuclear plant

The 1979 accident at the Three Mile Island power plant, the worst in US history, claimed no lives but provoked an outcry over the country's nuclear electricity program.

Caused by mechanical, design and human errors, the partial meltdown registered a five on the International Nuclear Event Scale that peaks at seven, the rate given to the Chernobyl (1989) and Fukushima (2011) disasters.

Here is a rundown of what happened on March 28, 1979 at one of the two reactors at the Three Mile Island Generating Station in eastern Pennsylvania.

Early morning alert

An alert was declared at 4:00 am after a fairly minor malfunction in the 's cooling system that was linked to a filter.

Authorities quickly emphasized there had been no radioactive leaks.

The in question, TMI-2, automatically shut down. However engineers did not know that a pilot-operated relief valve remained open, allowing coolant to escape.

A high pressure back-up system immediately pumped back into the reactor. However technicians feared that too much pressure would build up and reduced the flow of water.

Partial meltdown

As sufficient cooling was prevented, the reactor core heated up; water evaporation exposed the fuel core and temperatures climbed even higher.

The reactor remained intact, though a subsequent investigation determined that about 45 percent of its core had suffered a meltdown.

Radioactive material called corium flowed to the bottom of the , where it was contained, which averted disaster.

Engineers finally realized they had to restore the high pressure flow of water.

They were able to gradually vent built-up radioactive gases to waste tanks.

Some radioactivity, however, escaped into the atmosphere through a system of filters that officials insisted retained the most dangerous elements.

Five days of fear

Uncertainty and fear reigned for five days before the situation was declared under control.

During that time residents were told to stay indoors with windows closed.

More than 100 pregnant women and young children who lived close to the power plant were evacuated to a covered skating rink.

President Jimmy Carter, who had studied , visited the site on April 1 to reassure the public.

It was not until April 27 that a natural convection circulation of coolant was reestablished, according to a World Nuclear Association account of the accident.

Panic, thousands flee

The accident caused major panic, fed by confusion and poor communication between state authorities, the Nuclear Regulatory Commission (NRC) and the media.

More than 140,000 people fled during a two-day exodus that rendered any official evacuation plans useless.

With the exception of four plant employees, the NRC determined that millions of locals had only been exposed to about the same amount of radioactivity they would absorb during a routine chest X-ray.

Costly aftermath

The clean-up operation lasted until 1993 and cost an estimated $973 million.

The 900 megawatt reactor, designed to provide 900,000 homes with electricity, was scrapped.

Although no one died and no immediate injuries were linked to the incident, no new nuclear have been built in the United States since then.


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Mar 28, 2019
"...exposed to about the same amount of radioactivity they would absorb during a routine chest X-ray..."
"...no one died and no immediate injuries were linked to the incident..."
"...no new nuclear power plants have been built in the United States since then..."
It was an "accident" where no one died from radiation exposure, and the radiation level was lower than a dental X-ray or a bunch of bananas.
The biggest beneficiary was the fossil fuels(backup for intermittent renewables) which air pollution respects no border and kills millions of people annually.

"Even the worst nuclear accidents result in far fewer deaths than the normal operation of fossil fuel power plants."
"The fossil fuel industry in ONE DAY does vastly, vastly more damage to the planet and to human life than the entire civilian nuclear industry has done in sixty years."
death/TWh: coal 161.00, oil 36.00, solar 0.44, wind 0.15, hydro 0.10, nuclear 0.04
https://pbs.twimg...XKgO.jpg

Mar 28, 2019
"...The clean-up operation lasted until 1993..."
Around one year after Three Mile Island, the eruption of Mount St Helens released as much radioactive material as all nuclear weapons, as well polonium-210 worse than cesium-137 and protactinium-231 equivalent to plutonium-239 in terms of toxicity,
and it wasn't done any "clean-up" operation regarding radioactive materials.
https://pbs.twimg...gopu.jpg
https://pbs.twimg...Iqax.jpg

"LNT assumes that there is no threshold below which radiation is safe, but that assumption has been discredited over recent decades by multiple sources of data."
"In fact, residents of Colorado, where radiation is higher because of high concentrations of uranium in the ground, enjoy some of the lowest cancer rates in the U.S."
https://www.forbe...ly-safe/

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