PNL science to help clean up nuclear waste
April 14, 1995
RICHLAND, Wash. –
The Pacific Northwest Laboratory is using its nuclear fuel expertise to help the U.S. Department of Energy solve one of Hanford's most urgent problems -- safely storing more than 2,100 metric tons of highly radioactive spent nuclear fuel stored at the K Basins. The fuel, some of which is severely corroded, is a result of Cold War reactor operations at Hanford and still contains plutonium and uranium.
"PNL has begun a series of destructive and nondestructive analytical tests of the fuel to determine its physical condition and corrosion characteristics," said Paul Turner, PNL's manager of the spent nuclear fuel project.
The data gathered from PNL's studies will be used by DOE to help develop a strategy for removing the spent nuclear fuel from the aging K Basins and storing it safely elsewhere at Hanford. DOE's plan is to remove this threat to the nearby Columbia River by 1999, beating the Tri-Party Agreement's December 2002 target milestone for moving the fuel into stable, dry interim storage.
PNL recently received three spent fuel rods from the K West Basin -- an obsolete 40-year-old concrete water-filled basin located near the Columbia River -- and will be conducting its studies at DOE's 327 Building. The 327 Building, located in Hanford's 300 Area and managed by PNL, contains several hot cells that have been modified to accept the K Basin fuel.
The individual fuel rods, still in their shipping canisters, will be stored in a holding tank inside 327 as PNL scientists begin the examinations. The first nondestructive test will take place as the fuel canisters are moved from the holding tank to the hot cells, and the fuel rods are removed and exposed to air for the first time since being stored in the K Basins decades ago.
"By exposing the fuel to air, we learn a lot about the fuels' chemical reactivity, which will help us identify safe methods for handling it in the future," Turner said.
After PNL scientists have determined how the fuel reacts to air, they will conduct a visual inspection, weigh, measure and photograph it. Once the visual and physical examinations are complete, the fuel assemblies -- two-feet long, 55-lb zirconium-clad tubes containing uranium metal -- will be cut and sectioned.
PNL scientists then will test the cut pieces of fuel to determine the chemical and physical properties. Specifically, scientists will look for signs of corrosion, cracking or swelling of the fuel and also determine at what temperature it burns.
"By understanding the fuel's characteristics and how it may have changed since it was placed in the K Basins some 10 to 25 years ago, decisions can be made concerning how to prepare it for long-term dry storage," Turner said.
PNL's study of the K West fuel is expected to take about six months, at which time a second fuel shipment from the K East Basin will be delivered for similar tests. The tests for the K East fuel will be based upon the knowledge gained from the K West study.
After each study is completed, the fuel will be packaged and sent back to the K Basin in which it was originally stored. Any material removed from the assemblies will be sent to Hanford's Central Waste Complex.
Tags: Energy, Operations