The demonstrations will help determine the complexity of retrieving the actual waste from storage bins in the Calcined Solids Storage Facility (CSSF) prior to the facility’s closure at the Idaho Nuclear Technology and Engineering Center (INTEC).
About 4,400 cubic meters of calcine are in storage in six separate bin sets inside concrete vaults. The bins are a series of long cylinders, and the number of bins in each set varies. Workers are using a full-scale mock-up of a bin for the demonstrations.
The calcine is a dry, granular byproduct from converting liquid waste generated during historic spent nuclear fuel reprocessing into a more stable solid. It must be retrieved and ready to leave the state of Idaho by 2035, in compliance with the 1995 Idaho Settlement Agreement. Demonstrating retrieval is an important step toward that milestone.
The demonstrations are occurring at the former Fuel Reprocessing Restoration Facility (CPP-691), which was constructed in the late 1980s to reprocess spent nuclear fuel and recover unused uranium. The building was not completed since the U.S. stopped reprocessing in 1992 due to nuclear proliferation concerns.
“We’ve done some testing on our retrieval technologies at a local fabrication shop, but this is the first time that we’ve brought this equipment to the site to be tested on the full-scale model,” Fluor Idaho Project Manager Howard Forsythe said. “We’ll get to see how effective each piece of equipment is and its effectiveness at operating in concert with another technology.”
A full-scale model of the CSSF 1 bin was constructed to simulate retrieval of calcined waste from the CSSF 1 bin set — the oldest of the six bin sets — for transfer to a newer one with storage capacity. This process will provide the regulatory framework for closing the remaining bin sets after the calcine is removed for treatment and disposition.
Retrieving calcined waste from the CSSF 1 bin set will be the most challenging of all six bin sets because the bins were not designed for retrieval and lack access risers. Also, the CSSF 1 bin set has internal obstructions that could limit access within the bins.
Crews transported and installed the CSSF 1 bin replica in a below-grade cell at CPP-691, and they installed bulk retrieval equipment and associated instrument control systems on the main level. The bin model will be used to test the bulk retrieval equipment and waste retrieval components, such as the residual cleanout and visual equipment systems.
Forsythe’s team spent six months rehabilitating CPP-691 by removing excess equipment and supplies, establishing permanent electrical power, and installing required safety equipment. The building will serve as the demonstration area to test retrieval designs and operations.
Initial system testing is complete, and project engineers and operators are preparing for the first surrogate material transfer.