Science panel says Yucca too small for Idaho nuke waste

Friday, Dec. 17, 1999 | 10:20 a.m.

More than 12,000 cubic feet of high-level nuclear waste stored in Idaho may not fit into a proposed repository at Yucca Mountain and should stay where it is, a national scientific panel warned.

The National Research Council told the Department of Energy on Thursday that the highly radioactive wastes from federal government reprocessing of reactor fuels should stay at the Idaho National Engineering and Environmental Laboratory until treatment and disposal decisions are made.

Yucca Mountain, 90 miles northwest of Las Vegas, is the only site under study by the DOE to dispose of 77,000 tons of commercial and Defense Department nuclear wastes, but the mountain has not passed scientific muster as a repository.

It will take another 10 to 13 years before a Yucca repository could be ready if the mountain is approved, the DOE has said.

Yucca Mountain may not have the space to keep Idaho's waste on top of its burden from the nuclear industry and nuclear weapons development, the council's report concluded. The council urged Idaho to plan on keeping the wastes in steel bins beyond 2035.

"Before making any decisions on how to treat the solid waste at INEEL, the U.S. Department of Energy should move aggressively to identify an acceptable site with the capacity to receive the material, routes to transport the waste for disposal and treatment methods that will meet regulatory requirements at the disposal site," Robert Forney, retired executive vice president of DuPont and chair of the council's report committee, said.

"In the meantime, leaving the solid waste in place is the safest and most practical course of action," Forney said.

The report noted that the DOE does not yet have plans to build a second underground repository equipped to handle Idaho's wastes, adding to the argument to keep the wastes where they are today.

From 1953 until 1992 Idaho's federal lab reprocessed a variety of spent nuclear fuels. The wastes from that process were converted into a solid, high-level waste form known as calcine.

The calcine is stored in sets of stainless steel bins encased in concrete vaults. Those bins are designed to keep the wastes secured for 500 years, and radioactivity will decrease over that time. The council urged the DOE to perform a risk analysis to ensure the containers' safety.

Idaho and the DOE reached a recent agreement to convert the wastes by 2035 for disposal out of state. For decades the DOE has studied ways for treating the calcine wastes such as converting it into solid glass, cement or ceramic forms for disposal.

After the waste is repackaged and declared safe for shipping, it would be disposed of at specially designed underground facilities.

The council said the permanent site where the waste will go has to be identified in advance so the calcine will be converted into a form appropriate to the site.

The council's report noted that many regulatory, legal and technical problems need to be resolved before a disposal site is designated.

Since the federal government reprocessed the wastes, they would need to go to a geological repository such as that proposed at Yucca Mountain, except the requirements that calcine will have to meet for disposal have not been designed or approved, the report said.

In addition, more than 15,000 cubic feet of liquid wastes, considered both radioactive and chemically hazardous, are contained in tanks that do not meet long-term storage regulations. The DOE is committed to emptying the tanks by 2012.

But the report urges the DOE not to convert the low-level radioactive liquid into calcine, adding to the high-level wastes.

Instead, the liquid should be converted into a low-level radioactive solid form that can be shipped to licensed waste disposal facilities.

By turning the liquid into solid form, the DOE reduces the risks that the waste would leak. The liquid could be converted by chemical evaporation or by separation processes designed by the DOE.

A small amount of residual waste will remain in the storage tanks and bins. The report urged the DOE to consider the costs and risks of leaving it in place before developing criteria for permanently closing the storage containers.

The study was funded by the DOE. The National Research Council is the principal operating agency of the National Academy of Sciences and the National Academy of Engineering, private, nonprofit institutions that provide science advice under congressional charter.