Three Mile Island
Episode of Stuff You Should Know · June 4, 2026 · 46 min
Josh Clark and Chuck Bryant recount the 1979 Three Mile Island nuclear accident, its causes, health debates, cleanup, and effect on U.S. nuclear power.
Summary
Josh Clark and Chuck Bryant walked through the March 28, 1979 partial meltdown of the TMI-2 reactor near Middletown, Pennsylvania, noting it came just 12 days after the release of The China Syndrome. They described how a cooling-system fault triggered an automatic shutdown, after which a stuck pilot-operated relief valve, misleading instrumentation, and operators shutting off emergency coolant exposed the reactor core. Clark argued that the industry and regulators held deluded, overly optimistic views of nuclear safety that shaped the response.
The hosts covered the slow notification of the Nuclear Regulatory Commission, Metropolitan Edison's misleading statements, Governor Dick Thornburgh's partial evacuation advisory, the hydrogen bubble scare, and President Jimmy Carter's visit to the plant. They discussed the Kemeny Commission's criticism of NRC training requirements, design flaws such as an indicator light that showed only that a valve was ordered closed, and Charles Perrow's concept of the 'normal accident.'
On health effects, Clark said he was persuaded by the broad consensus that released radiation was too low to harm health, while acknowledging residents' reported symptoms and bitterness; Bryant noted studies suggesting elevated infant deaths and cancers that could not establish causation. They described the decades-long cleanup, Met Ed's small fines, a 1996 test case ruling against plaintiffs, whistleblower Rick Parks, the cancellation of dozens of U.S. reactors, the No Nukes concert, and Microsoft's deal to buy power from TMI-1 for AI data centers. The episode closed with a listener correction about Thomas Hobbes.
Chapters
- 1:50
Intro and Stuff at Sea
The hosts open the show and promote their Virgin Voyages live-podcast cruise.
- 2:57
Setting the scene
The hosts introduce Three Mile Island as the worst U.S. nuclear accident and note the timing of The China Syndrome and the industry's overoptimism.
- 6:58
How the accident unfolded
A cooling fault, stuck relief valve, and operators shutting off emergency coolant led to the core being exposed.
- 13:45
Notification, confusion and evacuation
Delays reaching the NRC, Met Ed's misleading statements, and the governor's evacuation advisory caused public panic.
- 18:53
Hydrogen bubble and Carter's visit
A hydrogen bubble raised explosion fears before being vented, and President Carter toured the plant to reassure the public.
- 22:36
Investigations and design failures
The Kemeny Report faulted NRC training, and the hosts list instrumentation flaws and the 'normal accident' concept.
- 29:00
Radiation and health effects
The hosts weigh studies finding negligible radiation impact against reports of cancers and residents' symptoms.
- 33:06
Cleanup and aftermath
The reactor reached cold shutdown, and cleanup of fuel and contaminated water stretched for decades.
- 37:26
Protests and No Nukes
Public opinion turned against nuclear power, prompting protests and the 1979 No Nukes concert.
- 40:14
Legal fallout and legacy
Met Ed's fines, lawsuits, a whistleblower, canceled reactors, and Microsoft's TMI-1 power deal are discussed.
- 45:09
Listener mail on Hobbes
A listener corrects the hosts' characterization of Thomas Hobbes and shares facts about his life.
Key points
What was said, by whom, with the exact words. Timestamps jump to the moment.
- Josh Clark
Clark argues that the nuclear industry and regulators were collectively deluded about the safety of nuclear power at the time.
“Like they were deluded as a group about the safety of nuclear power”
- Josh Clark
Clark says operators had known of problems with the relief valve for weeks and falsified information rather than fixing it.
“There had been problems with that pilot-operated relief valve for apparently weeks. And rather than fix it, they were just falsifying the information”
- Josh Clark
Clark says Metropolitan Edison lied about the severity of the accident, even privately to the governor and lieutenant governor.
“And they were just lying their faces off. They just said whatever they thought people wanted to hear”
- Chuck Bryant
Bryant says the investigation found the NRC had lax requirements that left operators ill-prepared for emergencies.
“It was the NRC apparently who like had lax requirements”
- Josh Clark
Clark describes Three Mile Island as a 'normal accident' in Charles Perrow's sense, inevitable given the complex system's design.
“there's a sociologist named Charles Pero who calls this a normal accident, which is basically an accident that is essentially inevitable”
- Chuck Bryant
Bryant explains that the relief valve's indicator light showed only that it had been ordered closed, not that it was actually closed.
“The indicator lit up when it was ordered to close, not confirming that it was closed”
- Josh Clark
Clark concludes that the consensus that radiation releases were too small to affect health appears to be correct.
“Almost everybody agrees that there was not enough of a radioactive release to actually affect human health or the environment”
- Chuck Bryant
Bryant notes studies finding increased infant deaths, cancer rates, and thyroid cancer correlations, though none proved causation.
“There was a 2017 study that found a correlation between thyroid cancer and living in that region”
- Josh Clark
Clark says he can understand residents who believe relatives died from the accident being deeply bitter at being dismissed.
“everybody's telling you like no it's it's fine you're you're hysterical overreacting i can't imagine yeah not being deeply bitter about that”
- Josh Clark
Clark says the containment vessel held molten uranium by sheer luck despite not being expected to withstand it.
“And it actually had not been expected to be able to stand up to something like that. And just by sheer luck, it did”
Linked moment · 38:27Skip to 38:27 using a listen link in the info box.
Chuck BryantBryant recommends watching the No Nukes concert film, calling it peak Bruce Springsteen.
“Watch the concert film of the No Nuke show. And it is peak, peak Bruce Springsteen. Unbelievable show”
- Chuck Bryant
Bryant cautions that critics say the Netflix documentary's whistleblower account is misleading and should be taken with a grain of salt.
“He did raise concerns about that crane, but they didn't ignore them”
- Josh Clark
Clark argues Three Mile Island is almost entirely why nuclear energy is not widespread in the United States.
“the reason why nuclear energy is not widespread, especially in the United States, is because of Three Mile Island, almost 100%”
- Chuck Bryant
Bryant reports Microsoft signed a 20-year deal to buy power from TMI-1 starting in 2028 to supply AI data centers.
“Microsoft signed a 20-year deal to purchase power from TMI1 starting a couple of years from now in 2028”
People
In the conversation
- Josh ClarkCo-host of Stuff You Should Know
- Chuck BryantCo-host of Stuff You Should Know
Discussed
- Jimmy CarterFormer U.S. president said to have been briefed on UFOs
- Dick ThornburghGovernor of Pennsylvania during the accident
- John KemenyDartmouth College president who led the presidential investigation
- Charles PerrowSociologist who coined the 'normal accident' concept
- Jane FondaActress, Turner's former wife
- Rick ParksCleanup supervisor and whistleblower at Three Mile Island
- Bruce SpringsteenRock musician whose concert the speakers discussed
- Thomas HobbesEnglish political philosopher, subject of listener correction
Topics
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From the publisher
The disaster at Three Mile Island thankfully did not cost any lives directly, but the notion that it didn't harm people is very much up in the air. Learn all about the worst nuclear disaster in the history of the United States today. See omnystudio.com/listener for privacy information.
Summary, chapters and key points were generated from the episode transcript on September 28, 2026. Quotes are checked word for word against the transcript.