Roger Mattson, Victor Stello and the Hydrogen Bubble
Roger Mattson and Victor Stello went back a long way. Together they had worked as part of the Atomic Energy Commission, when nuclear power was in its infancy. The two men, though different in demeanor and approach, held each other in high regard. In the early days of the accident they worked together at the Emergency Management Center, established by the NRC. Little did either man know that later a rift would develop between the two engineers that would send a shock wave through the entire nation.
Mattson, who was considered the nation's leading expert on emergency core cooling, came to the startling conclusion that a hydrogen gas bubble had formed above the reactor core. Speaking to NCR Chairman Dr. Joseph M. Hendrie, Mattson said, "They can't get rid of the bubble. They have tried cycling and pressurizing and depressurizing; they have tried natural convection a couple of days ago; they have been on forced circulation; they have steamed out the pressurizer; they have liquided out the pressurizer. The bubble stays." Mattson explained that in order to shut the reactor down, they must reduce the pressure. But lowering the pressure caused the bubble to get bigger. A bigger bubble could push all the water right out of the core and lead to a meltdown. Mattson told Hendrie they were involved in a "horse race," and he was quite unsure as to whether they could win it. Meanwhile, word of a possible meltdown begin to ripple through to the press. That night news anchorman Walter Cronkite, one of the most trusted men in America, updated the nation as to the gravity of events at Three Mile Island: "The world has never known a day quite like today. It faced the considerable uncertainties and dangers of the worst nuclear power plant accident of the atomic age. And the horror tonight is that it could get much worse. The potential is there for the ultimate risk of meltdown at Three Mile Island...."
Victor Stello traveled to Harrisburg with Harold Denton on Friday, March 30, the day of Cronkite's somber broadcast. According to Mike Gray, the screenwriter of the film "The China Syndrome," Mattson confronted Stello on Sunday as they waited for Carter to arrive and the two men engaged in a heated debate over the potential for the hydrogen bubble to explode. At the time President Carter entered the plant, the legitimacy of the hydrogen bubble risk was still undetermined.
On Sunday afternoon, while Carter was still there, Victor Stello found the proof he needed. They discovered that Mattson and his team of consultants had been using the wrong formula to determine the risk posed by the hydrogen bubble. Stello concluded that "hydrogen under pressure will prevent water from breaking apart into hydrogen and oxygen because it will tend to suppress the creation of more hydrogen. Without free oxygen, there can be no explosion." Plant operators began hooking devices to the containment building in order to slowly burn away the hydrogen, thereby bleeding away the bubble.