Thirty years ago today, on March 28, 1979, at 10:55 a.m, some 6 hours and 55 minutes after the sudden shut down of the TMI-2 reactor, Pennsylvania Lt. Governor William Scranton issued this statement: “The Metropolitan Edison Company has informed us that there has been an incident at Three Mile Island, Unit #2. Everything is under control. There is and was no danger to public health and safety.”
That was a lie.
At least 30 percent of the reactor’s core had melted and slumped to the bottom of the the reactor pressure vessel. That the vessel didn’t rupture was a lucky turn of events because, had it ruptured, the core would have dropped to the floor of the reactor building, creating conditions where there could be no assurance that a catastrophic radioactivity release could be prevented.
Three days after the accident began NRC officials were debating the likelihood of this worst case scenario; some believed disaster was in the offing and others argued that the danger had passed. I reported that fact for The Associated Press and was promptly denounced as fabricator and a fool by Pennsylvania’s governor at the time, Dick Thornburg.
Three Mile island photo courtesy Blain Roberts
Notwithstanding ensuing multiple investigations by a presidential commission, government agencies and congressional committees, much remains unknown about critical events associated with the accident. One thing though is clear: During the early hours of the accident a catastrophe was a lot closer than was known by government regulators or the public. And by the time the regulators had before them the information indicating the nature of what had happened, the danger had largely passed, even though, at the time, the experts disagreed on whether this was so.
For those of you who weren’t born yet, or who slept through those frightening days in late March weeks in March and April, here is a link to today’s edition of the Casco Bay Observer.
Don’t let its pastoral name fool you. The newsletter is written by Dr. Henry Myers, a physicist with degrees from MIT and Caltech, who was the chief scientist for former Rep. Mo Udall’s ball-busting investigative committee that watched over the NRC and other issues that glowed in the dark. Henry was there for it all and if you care about truth in government, read what he has to say
Casco Bay Observer
March 28, 2009
TMI + 30
On Wednesday, March 28, 1979 at 10:55 a.m, some 6 hours and 55 minutes after the sudden shut down of the TMI-2 reactor, Pennsylvania Lt. Governor William Scranton issued this statement:
The Metropolitan Edison Company has informed us that there has been an incident at Three Mile Island, Unit #2. Everything is under control. There is and was no danger to public health and safety.
The incident occurred due to a malfunction in the turbine system. There was a small release of radiation to the environment.
All safety systems functioned properly. …
On Wednesday at 4:30 p.m. Lt Governor Scranton issued an update:
Begin indent, begin different font
The situation is more complex than the company first led us to believe. We are taking more tests, and at this point, we believe there is still no danger to public health.
Metropolitan Edison has given you and us conflicting information. ….
On Thursday, March 29, unaware of data indicating melting of the core, the NRC chairman assured anxious and skeptical members of the House of Representatives Interior Committee that there had been no melting of fuel. He estimated that there has been a small amount of fuel damage ( “perhaps about one percent of the fuel in the core” ) in the form of cracks in the tubes that contained the uranium pellets. (On May 9, 1979, Victor Stello, then chief of the NRC’s Division of Operating Reactors, told congressional investigators, that with respect to the NRC’s March 28 and March 29 reports on percentage of fuel damage, “I do not know why anybody would be guessing at the percent of failed fuel.”)
On Friday, March 30, the NRC commissioners learned that the accident had been much more severe than they had previously believed. NRC staff told the commissioners that the staff had that morning learned of evidence that at about 1:50 p.m on Wednesday a hydrogen explosion had occurred in the TMI-2 reactor building. The report of an explosion plus data indicating a continuing presence of hydrogen in the pressure vessel pointed to severe core damage and the possibility of further explosions that might lead to a large off-site release of radioactivity. Talk then centered on the situation being one that safety systems “never had been designed to accommodate, and …. the best estimate (is that it is) deteriorating slowly, and the most pessimistic estimate is (that it is) on the threshold of turning bad.” There then followed indeterminate discussion of whether the state’s evacuation plan should be executed.
On Saturday, March 31, Commission concern focussed on the likelihood of disaster. Late in the day, the perception of danger peaked. By mid-day Sunday, April 1, a consensus had developed that a catastrophe was not in the offing and that it was safe for President Carter to tour the control room. Meanwhile, controlled radioactivity releases from the plant, words of caution from Pennsylvania Governor Dick Thornburgh, press reports rooted in the NRC commissioners’ discussions, and rumors of explosions and meltdowns caused a major exodus from the TMI/Harrisburg area.
The accident triggered numerous investigations including several by the NRC, by a presidential commission, by disparate congressional committees and by journalists and book writers. Some of the latter, including one by the NRC’s designated historian, were off the wall. Notwithstanding that the extensive scrutiny left critical questions dangling, the inquiries in toto did reveal a particularly noteworthy aspect of the matter: there had occurred a significant number of episodes that beforehand would have been deemed by the nuclear industry and NRC regulators not credible, the stuff of anti-nuclear hype.
Among a-priori implausible events was the failure of the NRC to respond to warnings that operators would be confused by a malfunction like that which set the stage for disaster at TMI-2. One such event was at the Davis-Besse reactor that began as did the March 28 TMI accident. Another was a safety analysis by a TVA engineer of a TMI-like reactor being purchased by TVA. Had these precursors been addressed, the TMI-2 operators would probably have realized that water was flowing out of the reactor pressure vessel through a stuck open valve and they would have known what to do to stop the flow and to restore cooling prior to the occurrence of fuel damage.
Prior to the TMI accident, plant workers falsified leak rate calculations; this resulted in the failure to repair a leaking valve which later played a primary role in causing the accident and the operators’ failure to perceive what was happening.
For the accident’s first 2 hours and 18 minutes, the operators did not recognize that water was flowing from the pressure vessel through the previously leaking but now stuck open valve, leaving the highly radioactive reactor core inadequately cooled. At approximately 6:20 a.m., an arriving shift supervisor perceived the problem; he instructed an operator to close another valve near the one that was stuck open. This stopped the flow of water from the reactor. But it was too late. Before cooling was restored, fuel temperatures rose to the melting uranium oxide point. A substantial portion of the 100 tone reactor core had liquefied and slumped into the bottom of the pressure vessel which fortunately maintained its integrity.
While the greatest danger existed during the accident’s first hours on March 28, it was, as noted above, not until March 30 that NRC Commissioners learned that the event was much more serious than they had previously believed. In days, weeks and months following the accident, information emerged indicating that on March 28 control room instruments and other data indicated that the fuel had been severely damaged, a situation that TMI’s managers were required to report immediately to the NRC. Instead of passing on this data to State and Federal officials, however, plant managers made misleading statements, creating the impression that the accident was substantially less severe and the situation more under control that what the managers themselves believed and what was in fact the case. While the failure to report accurately was a clear and serious violation of then existing NRC regulations, the NRC staff took no action against the responsible managers, dismissing and obfuscating the matter with Alice-in-Wonderland distinctions between “knowing” and “willful” withholding of information.
For those who see TMI as a demonstration of the great safety built into the nuclear technology, there is another way of looking at the story. Had the cards fallen more favorably, the fact of a stuck open valve would have been recognized and dealt with early on and the event would have gone virtually unnoticed by the press and public at large. On the other hand, had the cards fallen less favorably (with another hour or two, in addition to the 2+ that passed prior to a manager noting that fluid was flowing from the reactor through the stuck open valve), the core would have fallen through the pressure vessel into the reactor building which was not designed to keep radioactivity from escaping into the plant’s surroundings. It is anyone’s guess as to whether in such circumstances there would have been a massive release of radioactivity with consequences of a kind that the industry and NRC contended had a probability of occurrence that was on the order of that of meteor strikes.