U.S. Department of Energy Office of Environmental Management team members at the Savannah River Site used ingenuity, teamwork and decades of experience to successfully replace damaged equipment essential to the site’s spent nuclear fuel dissolution and disposition mission.
Office of Environmental Management
November 19, 2024
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AIKEN, S.C. — U.S. Department of Energy (DOE) Office of Environmental Management team members at the Savannah River Site (SRS) used ingenuity, teamwork and decades of experience to successfully replace damaged equipment essential to the site’s spent nuclear fuel dissolution and disposition mission.
While performing startup of the electrolytic dissolver for the Fast Critical Assembly (FCA) mission at the H Canyon chemical separations facility, employees discovered some damaged electrical components and thru-wall connectors, which serve to bring electricity to the dissolver. The dissolver is used to process the fuel from the Japanese research reactor.
“The thru-wall connectors, which were installed in the ‘60s, are housed inside metallic sleeves that were then grouted into the canyon wall,” said Lead Project Engineer Chas Shiels of Savannah River Nuclear Solutions (SRNS), the site’s managing and operating contractor. “To replace them, we had to look at hand-drawn blueprints and diagrams and come up with a plan for their removal and replacement.”
Adding to the difficulty of interpreting 60-year-old drawings was the challenge of completing the work within the facility. Due to the high radiation of the canyon, all work is done either using remote cranes or, in some areas, with employees dressed in personal protective equipment, including plastic suits and hoods. The employees use equipment that supplies breathing air. The canyon is also filled with equipment such as dissolvers and piping that makes for tight working conditions.
To ensure the success of the fabrication and replacement of the damaged components, employees created multiple mock-ups in another area at SRS. They worked together to fabricate custom tooling and practice removing and installing the thru-wall connectors.
A view of the thru-wall corrector from the remote crane control room in the H Canyon chemical separations facility.
Savannah River Site team members fabricated a mock-up of a custom-made thru-wall connector onsite. They practiced with the mock-up before replacing the thru-wall connectors in the H Canyon chemical separations facility.
Pre-planning was essential to the successful execution of the replacement, SRNS Maintenance Lead John Charles Lollar said.
“Personnel protection during the work in the hot areas of the canyon was our highest concern,” Lollar said. “Pre-planning helped us implement controls, like distance and shielding, for these hazards.”
Lollar applauded the team for keeping positive and embracing teamwork.
“I can’t say enough about the teamwork involved in achieving this monumental task,” he said. “The dedication and hard work of our craft employees to ensure this job was accomplished and performed safely was instrumental to the successful completion of the job.”
Project Operations Lead Mike Baynham said that SRNS employees are always willing to go the extra mile to support the mission.
“We appreciated the support of SRNS and DOE executive leadership,” he said. “We basically refurbished a dissolver and its electrical components in three months. Many of our employees have spent all day every day working this project since April, and we are excited to see the project completed safely and successfully.”
The Japan Atomic Energy Agency sent the FCA fuel to SRS in 2016, fulfilling a pledge by Japan and the United States to remove all separated plutonium and highly enriched uranium fuel from the FCA reactor. The fuel is not covered, or clad, in aluminum, requiring an electrolytic dissolver to process. That process adds electricity to the traditional chemical dissolution method.
After work on the FCA is complete, the electrolytic dissolver will be used to dissolve other non-aluminum spent nuclear fuel currently in the site’s L Basin while chemical dissolvers will work on the disposition of spent nuclear fuel clad in aluminum.
-Contributor: Lindsey MonBarren
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