Demolition of High Flux Beam Reactor exhaust stack completed

March 16, 2021, 12:04PMNuclear News

Workers use the MANTIS to demolish the High Flux Beam Reactor's exhaust stack, a prominent part of the Brookhaven National Laboratory. Source: DOE EM

Work crews have demolished the High Flux Beam Reactor (HFBR) exhaust stack at Brookhaven National Laboratory, on Long Island, N.Y., the Department of Energy’s Office of Environmental Management (EM) reported last week.

The 320-foot-tall red-and-white stack was decommissioned and demolished under the direction of the DOE, with oversight by the U.S. Army Corps of Engineers.

Demolition work: Removal of the stack started in early January using a concrete chimney demolition system called the MANTIS. Work crews dismantled the stack down to its base, about 36 feet above ground, before fully demolishing it in late February.

The next steps for the project are the cleanup of soils, the removal of the below-ground stack infrastructure, and verification that cleanup goals have been met. The Oak Ridge Institute for Science and Education will conduct independent verification of the stack cleanup, according to the DOE.

The first rail shipment of the stack’s debris to off-site disposal will involve 65 intermodal waste containers loaded onto a 10-railcar train. About 45 additional containers are expected to be shipped as part of the second and final waste shipment.

BNL’s High Flux Beam Reactor exhaust stack before demolition. Source: DOE EM

Reactor history: The HFBR was a small research reactor that operated at BNL from 1965 through 1996 and was permanently shut down by the DOE in 1999. The HFBR’s mission was to provide a source of neutrons for research in materials science, chemistry, biology, and physics. It achieved criticality on October 31, 1965, and was originally designed for operation at a power level of 40 megawatts. In 1982, an equipment upgrade allowed for operation at 60 MW.

The reactor was shut down in 1989 to analyze the safety impact of a hypothetical loss-of-coolant accident and was restarted in 1991 at 30 MW.

The HFBR was shut down again for routine maintenance and refueling in 1996 when tritium was detected in nearby groundwater. Upon further investigation, a leak was discovered in the spent fuel pool that released tritium-contaminated water into the ground. The reactor remained shut down for three years for safety and environmental reviews. In January 1998, all the spent fuel was removed and shipped off-site to allow for the insertion of a stainless steel liner in the spent fuel pool for the restart of the reactor. In 1999, however, the DOE decided to permanently shut down the HFBR.

Job done: Removal of the HFBR stack will mark the completion of a cleanup job at Brookhaven required by a 2009 record of decision.

“Our crews worked through pandemic hurdles and intense weather delays to complete the HFBR stack demolition with zero safety incidents and zero vibration disturbances to ongoing laboratory operations,” said Paul Lucas, the project manager. “Using innovative systems like the MANTIS to safely control debris and minimize personnel on the demolition platform, we’ve made huge strides in EM’s cleanup scope at Brookhaven.”