High Flux Beam Reactor (HFBR) was a research reactor which was located at Brookhaven National Laboratory, a United States Department of Energy national laboratory located in Upton, New York, on Long Island, approximately 60 miles east of New York City. A successor to the Brookhaven Graphite Research Reactor, the HFBR operated from 1965 until 1996 and has been partially decommissioned.
History
The primary purpose of the HFBR was to produce neutrons for multiple scientific uses. The reactor provided a source of neutrons for multidisciplinary scientific research in materials science, chemistry, biology, and physics. The reactor was used in the formulation of Nobel Prize-winning theories of cooperative ordering in large collections of atoms .
The reactor first reached criticality on Halloween, October 31, 1965. About twice as large as the preceding BGRR, HFBR initially operated at a thermal power level of 40 megawatts. Following an equipment upgrade in 1982, the reactor was operated at up to 60 megawatts thermal; a safety reanalysis resulted in HFBR being shut down in 1989 and being limited to 30 megawatts thermal upon restart in 1991.
The HFBR shut down in December 1996 for routine maintenance and refueling. While shutdown, a leak of tritiated water was identified by routine sampling of ground water from wells located adjacent to the reactor's spent fuel pool. 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. However, in November 1999, the Department of Energy decided to permanently shut down HFBR.
Design
The HFBR was a heavy water cooled and moderated, enriched uranium fueled research reactor. The reactor core consisted of 28 individual fuel assemblies arranged in a close-packed array. The fuel material was enriched uranium alloyed in aluminum and clad with aluminum in curved plates. Heavy water (D2O) served as the moderator/neutron reflector and primary coolant. The reactor vessel was fabricated from an aluminum alloy and contained the active core, reflector, and control rods. The vessel consists of an 82-inch diameter spherical section welded to a 46-inch diameter cylinder. The overall height of the vessel assembly was 24.75 feet. There were nine horizontal beam entry tubes that are integral parts of the vessel's spherical section. The core region provided space and access for 16 experimental facilities.
The reactor was housed within a confinement structure topped by a semi-hemispherical dome. The reactor sat inside a confinement building constructed of welded steel plates supported by an I-beam framework that rests on a cylindrical base. The inside diameter of the hemisphere at its base is 176 feet 8 inches. The cylindrical base is 22 feet 4 inches high and rests on a bed plate that is bolted to the reinforced concrete foundation ring. The foundation of the confinement building is a 5 ft. thick reinforced concrete mat bearing on the soil beneath the building. The interior of the confinement building contained the reactor and biological shield and was divided into equipment, experimental, balcony, and operations levels. The operations level contained the control room, instrument and maintenance shops, labs and offices. The equipment level contained the spent fuel pool water purification system, pumps and heat exchangers, cooling systems, and the spent fuel pool. The experimental level was for scientific users. The reactor biological shield, which surrounded the reactor, occupied the central portion of this level. A large open space surrounding the biological shield housed experimental equipment and there were labs and offices along the perimeter wall. Offices, locker rooms, toilets, and HVAC equipment were located on the balcony. The confinement building has four access points: a personnel airlock; a forklift airlock; and two tractor-trailer airlocks, one located on the experimental level and one on the equipment level.
Nine neutron beam lines extended from the HFBR in a radial spoke pattern. Up to 15 experiments could be run concurrently on the nine beam lines. Two reactor operators and two supervisors crewed the HFBR control room around the clock. In addition to the beam lines, seven sample irradiation thimbles for neutron activation experiments were provided which extended from the spherical reactor vessel towards the nuclear fuel.