RICHLAND — Nearly 2,000 capsules containing radioactive waste at the Hanford Nuclear Reservation should be moved, in part because of earthquake danger, according to a new report by the U.S. Department of Energy’s Office of Inspector General.
The 1,936 capsules contain radioactive cesium and strontium and are held in a giant pool of water on the Hanford site, the nation’s most polluted nuclear weapons production site.
The report released Wednesday said a severe earthquake could cause a loss of power or water in the Waste Encapsulation and Storage Facility in central Hanford.
The Tri-City Herald said the report suggests the capsules should be moved to dry storage as soon as possible.
“We acknowledge the budgetary challenges facing the department and its impact on moving the capsules into dry storage,” report author David Sedillo wrote. “However we suggest that the manager (of the) Richland Operations Office expeditiously proceed with its plans to pursue a dry storage alternative … at the earliest possible time frame.”
Steps were taken to reduce the risk of a severe earthquake to the storage pool after the nuclear disaster three years ago in Fukushima, Japan.
The cesium and strontium were recovered from Hanford’s underground waste tanks from 1974-85, packed in corrosion-resistant capsules and placed in underwater storage at the Waste Encapsulation and Storage Facility. The waste is left from the past production of plutonium at Hanford for nuclear weapons.
The capsules, which are about 22 inches long, hold material with 106 million curies of radioactivity, or 32 percent of the total radioactivity at Hanford. The 13 feet of water covering them helps cool the capsules and protects workers from radiation.
The capsules were destined for the proposed Yucca Mountain, Nev., national repository, which DOE no longer plans to develop. That could leave the capsules stored at Hanford until 2048, when DOE plans to open a repository at a location yet to be determined.
The storage facility has been operating for almost 40 years and the concrete in the cells of its underwater pool has begun to deteriorate from radiation exposure.
“Weakened concrete in the walls of the pool increases the risk that a beyond-design earthquake would breach the walls, resulting in the loss of fluid, and thus, loss of shielding for the capsules,” the report said.
However, the report noted that an earthquake or other disaster more severe than the storage facility was designed for is “extremely improbable.”
After the Fukushima disaster, private contractor CH2M Hill Plateau Remediation Co. rearranged about 800 of the underwater capsules to better distribute their heat.
A loss of water in the pool could cause the capsules to corrode or be breached.
CH2M Hill issued a request for information to engineering firms in August to ascertain the cost and feasibility of dry storage.
If the Energy Department can find the money to move the capsules to dry storage, it would save money in the long run, the report said. The move would cost an estimated $83 million to $136 million. But then the storage cost would drop to $1 million a year, compared to the current underwater storage cost of $7.2 million annually.
The sprawling Hanford site is near Richland.