KENNEWICK, Wash. — A national repository may run out of space for the hottest radioactive waste it was designed to store if changes are not made, according to an audit by the Department of Energy Office of Inspector General.
That could be an issue for Hanford, which is expected to be one of the last DOE sites to be shipping waste to the nation’s transuranic repository, the Waste Isolation Pilot Plant, or WIPP, near Carlsbad, N.M.
At issue is space for remote-handled transuranic waste. At Hanford that is typically debris or other waste contaminated with plutonium that is so radioactively hot that it has to be handled with remotely operated equipment.
WIPP already has accepted 649 shipments of transuranic waste from Hanford, but all the waste has been contact-handled rather than remote-handled waste. Legally binding deadlines are expected to be set in 2016 for how much Hanford waste suspected of being remote-handled transuranic waste DOE must treat for disposal each year through 2030.
DOE also legally is required to have a conceptual design of facilities to treat remote-handled transuranic waste in 2016, although it could instead propose sending the waste to the nearby Perma-Fix Northwest plant for treatment.
WIPP disposes of transuranic waste from multiple DOE sites in underground units with remote-handled waste placed into the walls of the units and control-handled waste on the floor, according to the audit report released Friday. Once units are filled with control-handled waste, the remote-handled capacity in the unit is lost if it has not been used.
WIPP’s total capacity for transuranic waste is limited by law to 175,600 cubic meters with no more than 7,080 cubic meters of that remote-handled waste. Since WIPP began disposing of remote-handled waste in 2007 — eight years after it opened — it has used just 299 cubic meters of its remote-handled transuranic disposal capacity, according to the audit report.
The Office of Inspector General warned in 2003 that a continued focus on disposing of contact-handled waste would limit the amount of remote-handled waste that WIPP had space to accept, but DOE’s practices have not changed significantly, according to the audit.
It estimated that DOE has about 3,538 cubic meters of remote-handled transuranic waste planned to be sent to WIPP with as much as 1,500 cubic meters eventually added to that total. But WIPP has just 2,912 cubic meters of space left for it.
DOE has focused on shipping contact-handled transuranic waste to WIPP because it requires less time, work and money to process than remote-handled waste, according to the audit. Large volumes of contact-handled transuranic waste were ready for disposal, helping DOE meet different states’ requirements for waste removal and disposal, which primarily cover contact-handled transuranic waste, the audit said.
DOE is working with regulators to evaluate alternative configurations for waste disposal units, said Lindsey Geisler, DOE spokeswoman. It also is updating long-range WIPP plans to extend operations beyond 2035.
“These actions will help improve WIPP disposal capacity and operations,” she said.
However, the audit found that options DOE discussed with the Office of Inspector General may not completely solve the problem.
In addition to possibly relocating planned disposal units to allow more remote-handled waste to be placed, DOE also has been granted a permit modification by New Mexico to package some remote-handled waste in shielded containers so it would have the lower radiation dose rates of control-handled waste.
However, the cost for the shielded containers for a little more than half of the remote-handled waste could be more than $200 million, “which, given the current budget situation, may be cost-prohibitive,” the audit report said. DOE told auditors that transportation and other efficiencies could more than offset the costs of the containers.
DOE will incorporate the audit comments into its ongoing assessment of disposal operations as it continually looks for ways to improve, Geisler said.