Past PA
Three Mile Island: Near-Miss Nuclear Disaster
Season 2 Episode 1 | 10m 56sVideo has Closed Captions
At 4 a.m. on March 28,1979, alarms rang in the control room at Three Mile Island.
At 4 a.m. on March 28,1979, alarms rang in the control room at Three Mile Island Nuclear Generating Station on the Susquehanna River. he cascade of events and broader panic made the nuclear plant the site of the most serious and publicized incident in the history of American commercial nuclear power.
Past PA
Three Mile Island: Near-Miss Nuclear Disaster
Season 2 Episode 1 | 10m 56sVideo has Closed Captions
At 4 a.m. on March 28,1979, alarms rang in the control room at Three Mile Island Nuclear Generating Station on the Susquehanna River. he cascade of events and broader panic made the nuclear plant the site of the most serious and publicized incident in the history of American commercial nuclear power.
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Learn Moreabout PBS online sponsorshipJARED FREDERICK: Four AM, Wednesday, March 28, 1979.
An array of ringing alarms and flashing warning lights suddenly roused operators in a control room at Three Mile Island Nuclear Generating Station on the Susquehanna River.
Little could they have known, they were on the brink of the most serious and publicized incident in the history of American commercial nuclear power.
The flurry of ensuing actions, reports and debates continue to shape our national discourse on the pros and cons of nuclear energy.
[theme music] By the 1950s, nuclear power had transitioned from a complete government monopoly into a private enterprise.
In 1954, the Atomic Energy ACT empowered the atomic energy commission to balance the ongoing production of nuclear arms for the military with safe and efficient commercial production.
Over time, however, the commission was criticized for enabling the industry it was intended to regulate.
That dynamic led to the creation of the nuclear regulatory commission in 1975.
This independent government agency was to become the final arbiter of nuclear oversight in the United States.
The emergence of the NRC coincided with the opening of two nuclear units at Three Mile Island Nuclear Generating Station in 1974 and 1978.
Operated by metropolitan Edison and located near Middletown, only miles away from the State capital, the plant was welcomed by most residents as a sign of progress and a means of revitalizing the local economy.
After all, the financial and energy woes of the 1970s further highlighted the need for America to invest in nuclear power.
Amidst these developments, the staff of the fledgling nuclear regulatory commission was often overwhelmed by its responsibilities.
One NRC director claimed, we had more work than we could handle.
While experts within the organization believed that harmful nuclear incidents were the least likely of all possible disasters to occur, many also acknowledged that the pathways to potential nuclear accidents had yet to be thoroughly examined.
This issue became quite apparent on March 28, 1979.
[dramatic music] In the pre-dawn hours at Three Mile Island, nerve wracking uncertainty gripped plant staff as alarms for Unit 2 began to sound.
[beeping] One operator remembered that the control room console lit up like a Christmas tree and an avalanche of data and warnings created an atmosphere of confusion.
At one point, a radiation in the control room alert blared, compelling staff to wear emergency respirators.
A general emergency was sounded.
Technical breakdowns had stalled feedwater pumps from transporting water to steam generators.
Pressure within the system soon mounted.
Employees responded by opening a relief valve, yet that valve, unknowingly, remained open after it was meant to close and operators were unaware of an ongoing loss of coolant.
Then something truly strange happened.
The water level in the pressurizer was rising, although the pressure itself was still falling.
This was a scenario staff had not been trained for.
Water level and pressure were supposed to rise or fall together.
As such, the operators shut off the supply of emergency cooling water to the reactor.
The lack of water circulation coupled with the stuck open valve, meant the coolant level continued to fall as it boiled away.
This eventually exposed the reactor core.
All the while, very hot fuel rods of the partially exposed core reacted with steam.
That process gave off immense heat.
Enough to melt the fuel.
At the height of the incident, the core reached 4300 degrees.
When all was said and done, the reactor endured irreparable damage.
Almost half of the core melted inside the reactor.
Fortunately, the considerable safety margin in the reactor's design kept the core from melting through.
Not until emergency water was injected into the system later in the day did the coolant pumps finally restart.
But concern did not end there.
Trace amounts of radioactive gas were released into the environment as steam from the melted fuel escaped through the open pressure valve.
And that issue soon became a chief concern of the surrounding community.
Early on the morning of the 28th, a radio traffic reporter picked up chatter about fire and emergency crews being mobilized on Three Mile Island.
Word of the mounting situation was spreading around the Harrisburg area by 09:00 AM.
Pennsylvania Governor, Richard Thornburgh remembered the moment with cold realization.
The minute I heard that there had been an accident at a nuclear facility, he said, I knew we were in another dimension.
Miscommunication and perhaps a lack of transparency on the part of Metropolitan Edison fueled a sense of fear and distrust.
Reporters, local politicians and those within the Governor's office felt they were not receiving full and accurate assessments from company spokesmen.
When inspectors from the NRC arrived on site, they witnessed an eerie scene of employees scurrying about in radiation suits.
The spectacle instilled the sensation that something dreadfully troubling had occurred.
The unfolding disaster was perhaps as much psychological as it was technological.
Pandemonium ensued in neighboring communities.
Communication and information alike were muddled.
Harrisburg's civil defense sirens were triggered despite the fact there was no immediate threat.
Worries were heightened by popular culture of the time as well.
Just two weeks before the incident, the suspense movie, The China Syndrome had been released.
Depicting a fictional nuclear accident and a cover up at a California plant, the movie popularized the phrase implausibly suggesting that a meltdown could burn through the Earth all the way to China.
The film reinforced suddenly pertinent fears of corporate corruption and environmental devastation.
The NRC noted to the New York Times on March 29 that low radiation levels had been measured up to one mile from the plant and that traces had been found in the air up to 16 miles away.
The amount in the immediate area was described as above normal for the plant site, but below what was considered dangerous to health.
Even so, the commission recommended to governor Thornburgh that a limited evacuation for specific segments of the local community was advisable.
Thornburgh thereafter recommended that young children and pregnant women within a five mile radius of the plant relocate.
Loudspeaker trucks announced the message in the streets of Middletown, Goldsboro and elsewhere, but a far larger demographic heeded the call.
Over 140,000 residents left the area that week.
Additional dread existed over the possibility of nuclear radiation running off into the Susquehanna River and thereby flowing into the Chesapeake Bay.
Exhausted by his haggling with the power company, an increasingly agitated Governor Thornburgh pleaded with president Jimmy Carter for additional guidance and resources to alleviate the hysteria.
By that Saturday, additional fears arose when scientists hypothesized that a pocket of hydrogen at the top of the reactor vessel might mix with too much oxygen and explode.
Such an explosion never occurred due to the overall lack of oxygen in the system, but some experts argued over the likelihood of such an eventuality up to the very moment of president Carter's arrival on April 1st.
Carter, himself a former Naval nuclear engineer, realized the gravity of the situation and knew his presence might demonstrate to the public that all was under control.
Public fear of immediate peril soon eased and residents gradually returned to their homes.
According to the NRC, this was the most serious accident in US commercial nuclear power plant operating history.
Although its small radioactive releases had no detectable health effects on plant workers or the public, its aftermath brought about sweeping changes involving emergency response planning, reactor operator training, human factors and engineering, radiation protection and many other areas.
It also caused the NRC to tighten and heighten its regulatory oversight.
All of these changes significantly enhanced US reactor safety, but the incident wreaked considerable havoc for the once heralded nuclear industry.
Three Mile Island sparked fierce debate over the role of nuclear energy in the United States.
On the steps of the Pennsylvania State house and elsewhere, citizens loudly voiced their concerns.
The disaster coupled with already faltering economic outlooks for new nuclear power plants canceled the construction of dozens of proposed plants nationwide.
Unit 2 on Three Mile Island never reopened and $1 billion were spent on cleaning the damage.
The plant's Unit 1, which was unaffected directly by the happenings in 1979, closed in 2019, and is currently undergoing an extended decommissioning process.
Whether you are for or against nuclear power, the Three Mile Island incident remains a cautionary tale of the importance of oversight, transparency, scientific understanding and communication, especially in extreme moments of uncertainty.
The event, likewise, demonstrates that even if genuine disaster does not reach its fullest capacity, the specter of disaster is often enough to influence society and policy in long standing ways.
Thanks for joining us on this episode of Passe Pas.