The pulse jet mixers suck waste into their vertical tubes and then eject it forcefully back into the tanks. Unfortunately, they have not yet been shown to provide sufficient mixing at the scale necessary for the Vit Plant. They do, however, apply enough force to the slurry for the solids to grind away at the stainless steel of tanks and pipes, weakening them enough to risk leakage. Besides this erosion, there’s also potential for chemical corrosion. The Defense Nuclear Safety Board, which advises the White House, has called these problems “a show-stopper.”
“The way [the plant] is currently designed poses unacceptable risks. DoE now admits that,” says Tom Carpenter, executive director of the watchdog group Hanford Challenge. In December the Government Accountability Office issued a highly critical analysis of the Vit Plant’s unresolved safety issues
Disagreements over the safety risks have also prompted outspoken protests from several senior Hanford officials. Chief project engineer Gary Brunson resigned in January. Busche and former deputy chief process engineer Walter Tamosaitis filed whistleblower complaints alleging that their concerns about safety were suppressed by Bechtel. (Bechtel declined to be interviewed for this story, citing nondisclosure agreements signed with Chu’s expert panel.)
But Langdon Holton, DoE’s senior technical authority for the Vit Plant and a member of Chu’s expert panel, believes the project’s problems are technical snags, rather than the insoluble consequence of incompetence or hubris. He also thinks that although the current risks are real, they are unlikely and would be of low magnitude if they did occur. For example, he says, “You’d have to have a vessel unmixed for half a year” for enough hydrogen to accumulate for a significant explosion. “Do I have concern we won’t be able to resolve the issues? No, but it will take some time,” he adds. (Chu’s panel does not expect to issue a formal report, according to Holton.)
Time may be limited. The 177 tanks, built between 1943 and 1986 and most intended for only about a 20-year life span, are decaying; at last count, six are leaking. The Vit Plant was supposed to start operating in 2007 and is now projected to begin in 2022. Its original budget was $4.3 billion and is now estimated at $13.4 billion. Nobody is suggesting the project be abandoned, yet forging ahead without confidence in the plant’s safe operation is not really an option either. The real question, many Hanford watchers say, is whether the country wants to pay for doing it right.
Busche is adamant that the safety issues must be solved before plans proceed further. “The level of robustness we have to put in all our systems is derived from the waste itself,” she says. “It’s the gift that keeps giving until it’s in a glass log.”