Original Publication Date - 01/15/2001

Criticality issue heats up
By N.S. Nokkentved
Times-News writer

TWIN FALLS -- State and federal officials still disagree about the potential for a spontaneous nuclear reaction in buried radioactive waste at the Idaho National Engineering and Environmental Laboratory.

Over the long term -- hundreds of years -- officials agree radioactive waste in eastern Idaho may spontaneously set off an uncontrolled nuclear reaction.

Officials with the federal Environmental Protection Agency, however, have taken issue with recent statements by INEEL officials about the potential for such an event, known as a criticality.

The effects of such a reaction would be long-lasting and could affect the land's suitability for any future uses, long after the INEEL is closed.

Sue Stiger, head of environmental cleanup at INEEL, recently told The Times-News that state and federal officials at a meeting in December had agreed a criticality was not a concern at INEEL's burial ground.

But the EPA officials and consultants who attended the meeting don't agree, said Wayne Pierre, of EPA's Region 10 in Seattle.

They say INEEL doesn't have the data to back up that assertion. And a number of unresolved issues relating to the potential for a criticality were identified at that meeting -- contrary to Stiger's assertion, Pierre said.

Stiger was reached through a spokesman, who said INEEL officials don't disagree a criticality is a long-term concern.

"You can't rule out a criticality over an extremely long period of time," INEEL spokesman Nick Nichols said. But INEEL officials maintain a criticality is not an immediate concern.

"We're not ignoring the issue," he said.

INEEL officials have said they have completed "extensive criticality analysis" for the buried waste. EPA officials would like to see it.

Both sides agree it is an important consideration in any long-term decisions on how to deal with more than 2 million cubic feet of plutonium-contaminated waste buried willy-nilly in pits and trenches in the 1950s and 1960s.

"We're not talking about the China syndrome," Pierre said, referring to the myth that an uncontrolled, runaway nuclear reaction would melt its way through the earth.

A criticality in the pits and trenches would generate heat energy and gamma radiation -- an intense, highly penetrating form of radiation, more intense than X-rays.

The effects of such an event would last far into the future. And people forget, Pierre said. Someday long after INEEL is gone, people may use the area for a shopping mall or subdivisions, and they would be affected by the lingering radiation.

In addition, the heat released by a reaction could breach an engineered cap over the waste.

That doesn't mean all the waste must be dug up, Pierre said. But the hot spots should be identified and dug up. And EPA would like to see a study that identifies concerns, if any.

"That can't be done by somebody giving their verbal opinion," he said.

The complexity of the waste can't be assessed by inserting probes into the ground, Pierre said.

"There is a need to collect physical data," said Kathleen Trever, head of the state's INEEL Oversight Program. Actual waste would allow better understanding and improved long-term decisions about the fate of the waste.

Trever also is a little impatient with the apparent lack of progress with the buried waste. A project to dig up the one-acre Pit 9, which failed 2 1/2 years ago, was to have demonstrated how best to clean up the other 87 acres of buried waste.

For the first dozen years, the waste trenches were scraped down to the basalt. That practice later was changed to leave two to three feet of soil over the rock. The waste in those pits and trenches now threatens the underlying Eastern Snake River Plain Aquifer.

INEEL officials are working on alternative plans for the pit. Stiger said officials have submitted plans for a test excavation about 20 feet square for review by state and federal regulators.

Officials expect to start digging sometime in 2002. But the test excavations are expected to take 10 years.

Trever and others were hoping to see something before the final decision on all the pits and trenches is made.

Times-News writer N.S. Nokkentved can be reached at 733-0931, Ext. 237, or by e-mail at niels@magicvalley.com