Workers with DOE-EM’s Oak Ridge Office of Environmental Management (OREM) and cleanup contractor United Cleanup Oak Ridge (UCOR) began demolition of the Low Intensity Test Reactor in late March. Its teardown marks the second reactor to be taken down in Oak Ridge National Laboratory’s central campus over the past year. Last fall, OREM and UCOR completed the demolition of the Bulk Shielding Reactor (Building 3010), which sat adjacent to Building 3005.
The history: Built in 1949, the Low Intensity Test Reactor was a 3,000-kw reactor using high-enriched fuel and demineralized water as a moderator and coolant. The reactor was originally built as a hydraulic-test mock-up of the Materials Testing Reactor (MTR). It was converted to a training reactor for MTR operators in 1951 and subsequently was used as a testing reactor until ceasing operations in 1968.
The reactor became world-famous when a photographer first captured the blue glow caused by Cherenkov radiation in the pool above the reactor. That photo appeared on the cover of the October 1951 issue of Scientific American.
The work: Due to the unique conditions associated with the facility, demolition of the Low Intensity Test Reactor required nearly five years of planning and deactivation work. According to DOE-EM, employees identified structural concerns associated with the facility that posed significant challenges to standard deactivation and demolition practices.
“Demolishing this structure presented unique challenges,” said Brad Adams, UCOR project manager. “The outer structure had to be demolished in a way that didn’t disturb the reactor. A high-reach crane had to be used on a small footprint without disturbing other ORNL operations. Through hard work, perseverance, and ingenuity, we were able to safely bring down both the outer structure and safely pull out and package the reactor.”
Workers began demolition by removing the outer structure and various ancillary facilities. Next, workers used a high-reach crane to remove a trolley and bridge crane from the building. They then removed precast cement slabs and shield blocks to access and address the main reactor structure.
Once the slabs and shield blocks were removed, crews used a crane to raise the 37,600-pound reactor structure out of its housing. They placed the 30-foot-long reactor in a specialized carbon metal container for shipment for disposal.
In total, the demolition project produced more than 1.1 million pounds of waste. Workers were to ship the reactor to an approved waste disposition site within a few weeks, DOE-EM announced on September 26.
Next up: DOE-EM said crews are now busy preparing for deactivation and demolition of the adjacent Oak Ridge Research Reactor (Building 3042) and the Graphite Reactor support facilities.
