Test reactor to be dismantled
IDAHO FALLS – A test nuclear reactor in eastern Idaho that scientists originally intended to put through a meltdown to gather data about that type of catastrophe is being dismantled this year.
The Idaho National Laboratory’s Loss of Fluid Test reactor, built in the late 1960s, is a one-sixtieth scale version of a commercial nuclear power plant.
It performed accident scenarios and was put through other tests to improve nuclear power plant safety systems before being shut down in 1985.
It is being removed now as part of a seven-year, $7.9 billion project to clean up material and equipment left over from decades of tests at the 890-square-mile federal nuclear research area. Washington Group International, based in Boise, and CH2M Hill, based in Denver, are doing the cleanup.
Initial plans for the LOFT reactor were to have a meltdown of its nuclear core occur by making breaks in the pipes that delivered coolant. But nuclear regulatory agencies eventually decided the reactor was more useful as a safety testing facility.
The Atomic Energy Commission, the predecessor to the U.S. Department of Energy and Nuclear Regulatory Commission, “carefully handled the LOFT to avoid the question it was designed to answer,” Paul Leventhal, president emeritus of the Nuclear Control Institute in Washington, D.C., told the Idaho Statesman. “They were never prepared to bring it to melt and see what the consequences were.”
Instead, in 1977 researchers began using the LOFT reactor to see what would happen if a primary pipe break interrupted the coolant sent to the reactor. At the time, that was considered one of the most likely ways a meltdown of a nuclear plant could occur.
“If you look at the time when LOFT was being planned there were dozens of plants that had been ordered, and we were looking at a continued rapid growth of nuclear power,” Leventhal said. “The data out of LOFT was to be the insurance and verification that all future plants of similar design would be safe. But things didn’t quite turn out that way.”
On March 28, 1979, at the Three Mile Island nuclear power plant near Middletown, Pa., an open valve that interrupted coolant flow caused about half of that reactor’s core to melt. The result was a move away from nuclear power in the United States, and no new nuclear power plants have been built in the U.S. in more than 20 years.
“Three Mile Island was definitely a body blow to an industry that still hasn’t fully recovered,” Leventhal said.
Following the Three Mile Island meltdown, tests at the LOFT reactor helped explain what happened.
Jim Wolf, manager of the thermo fluids and heat transfer departments at INL, said that putting the LOFT reactor through a meltdown before the event at Three Mile Island probably wouldn’t have prevented the partial meltdown at the commercial plant.
“What Three Mile Island really did was point out a need for a continuing analysis and safety program,” Wolf said. “We found out that we didn’t know as much about plant behavior as we thought we did, but we saw it as an opportunity to go out and do the research and make sure that future plants were going to be safer.”
With current concerns about energy demands in the United States, nuclear power plants are being reconsidered.
“A lot was learned from the LOFT on how systems worked and didn’t work, but it may not be as applicable to new plants,” said David Lochbaum, director of the Nuclear Safety Project for the Union of Concerned Scientists.
He said more could have been learned from the LOFT reactor if it had been working before most nuclear power plants were built.