State and federal officials are investigating reports that workers detected elevated radioactivity levels under tank AY-102 during a routine inspection on Thursday.
According to technician Mike Geffre, who works for contractor Washington River Protection Solutions, an inspection was made of a pit under the tank. Its water samples had an 800,000-count of radioactivity and a high dose rate, which means that workers must reduce time spent in the area.
“Anything above a 500 count is considered contaminated and would have to be disposed of as nuclear waste,” Geffre explained. “Plus, the amount of material we’ve seen from the leak is very small, which means it’s a very strong radioactive isotope.”
If the waste escapes the tank and gets into the soil, it may reach groundwater and potentially the Columbia River.
“This is really, really bad. They are going to pollute the ground and the groundwater with some of the nastiest stuff, and they don’t have a solution for it,” Tom Carpenter, executive director of the Seattle-based advocacy group Hanford Challenge, a watchdog group that conducts environmental sampling to monitor for radioactive and chemical contamination, told AP.
There are 177 tanks holding up to 56 million gallons of waste, 149 of which are single-shell. Six of those tanks were discovered in February to be leaking at a rate of about 1,000 gallons annually.
AY-102 is one of Hanford’s 28 tanks with two walls, which was installed when single-shell tanks began leaking and some of the most radioactive liquid in those tanks was pumped into the sturdier double-shell tanks. The tanks are now beyond their intended life span.
Two radionuclides comprise much of the radioactivity in Hanford’s tanks: cesium-137 and strontium-90. While both take hundreds of years to decay, exposure to either can increase the risk of cancer.
Officials say that leaking tanks pose no immediate threat to the environment or public health, with the closest communities being several miles away.
“These last few months just seem like one body blow after another,” said Ken Niles of Oregon’s Energy Department. “It’s true this is not an immediate risk, but it’s one more thing to deal with among many at Hanford.”
“The Energy Department has been actively monitoring double-shell tank AY-102 since it was discovered to have a slow leak from the primary tank,” the department said in a statement. “Workers detected an increased level of contamination during a routine removal of water and survey of the leak detection pit.”
Additional testing is expected to take several days, though the state will demand an accelerated plan to deal with all the waste at Hanford, said Washington Governor Jay Inslee, adding that the potential leak “raises very troubling questions.”