Department of Energy contractor Savannah River Nuclear Solutions (SRNS) said its Savannah River Site employees recently used an innovative method to ensure the integrity of radioactive material storage containers currently in long-term dry storage at the South Carolina site.
“Two 30-gallon drums currently stored in the Dry Fuel Storage Area in L Basin contain radioactive materials that were shipped from the Idaho Chemical Processing Plant in 2007 and 2008, respectively,” said Steve Osteen, SRNS operations specialist.
“The material inside the drums is stored in plastic bags/plastic bottles and placed in sealed cans, which is a typical storage configuration for this type of material. It is also typical for hydrogen gases, which are flammable, to be generated by decomposition of plastics inside the sealed cans, which is why drums of this nature are assigned a year to be dispositioned before the Lower Flammability Limit is met. One of the drums was due to reach its limit in 2025, so we started working on a way to ensure both drums would remain safe for longer.”
The solution: According to SRNS, a team consisting of engineering, criticality engineering, operations, and radiological control personnel, along with Savannah River National Laboratory, evaluated the issue and concluded that venting the cans by piercing the top would relieve the pressure caused by the buildup of gases.
To accomplish venting, the team designed and fabricated a can piercer and a safe process to perform the task, including the use of a containment hut and protective plastic suits for operators.
The results: “The container piercing was executed safely and then the containers were returned to storage,” L Area Facility manager Neil McIntosh said. “The safe execution of this process was a result of extensive planning, dry runs, and mockups conducted by the team. The team used clean conditions to practice venting dummy containers while simulating the confines of the containment hut and donning of plastic suits. The evolution was practiced until proficiency was achieved and the team was ready to safely execute the work.”
The drums can now continue to be safely stored in the Dry Fuel Storage Area for an estimated additional 100 years, if needed.
The original disposition path involved sending the material through Savannah River’s HB Line facility, however changes in mission prevented it from being processed before HB Line went into safe shutdown status in 2020.