Workers have repaired a water leak at the Oak Ridge Research Reactor at Oak Ridge National Laboratory, officials said this week.
The completion of the work was announced by UCOR, a federal cleanup contractor and partnership between URS and CH2M Oak Ridge LLC.
The seep was detected in the reactor’s pool in September 2014. While it did not pose any immediate dangers to workers or the environment, it prompted quick action by the U.S. Department of Energy, which oversees ORNL. DOE asked UCOR, its prime cleanup contractor, to develop and implement a solution to remedy the seep, a press release said.
The Oak Ridge Research Reactor was built in the 1950s and began operation in 1958. For 30 years, it served as an isotope production and irradiation facility before being shut down in 1988. It has stood dormant and unused for more than a quarter century, the press release said.
It still held 125,000 gallons of water that provides protective shielding for radioactive components that remained in the pool.
“UCOR is used to working on complex cleanup projects and developing quick and effective solutions when unexpected issues arise,” said Ken Rueter, UCOR president and project manager. “Working with DOE, we developed a plan to ensure that the reactor seep would pose no harm to workers or the environment.”
The plan included removing the irradiated components from the pool, then capping and draining it. These actions would allow the former reactor to return to surveillance and maintenance mode awaiting eventual demolition.
In August 2015, UCOR removed four irradiated components from the pool. The four items, various metal plates weighing about 200 pounds each, represented about 96 percent of the radioactive material in the pool. They were moved by long-handled tools into a container that had been placed in the pool.
The container was then retrieved and moved by crane into a shipping cask set up next to the pool. The cask, which weighed about 80,000 pounds mostly due to its protective shielding, was then sealed for transport to the Waste Control Specialists Facility in Texas for disposition. UCOR enlisted the support of AREVA as a subcontractor to assist with long-handled pool work, loading, and transportation of the cask.
Following removal of the components, a concrete cap was installed over the top of the pool to act as a shield for remaining radioactive material in the pool.
In October 2015, workers began draining the pool. The water was forced through two filters over a three-week period to remove contaminated sediments. The drained water was then treated at the Liquid and Gaseous Waste Operations facility.
After the pool was drained, it was sealed with a paint-like material to lock in any loose contamination. The facility was then placed back into UCOR’s Surveillance and Maintenance program.
More information will be added as it becomes available.
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