High Flux Beam Reactor Facility Description
One of 10 national laboratories overseen and primarily funded by the Office
of Science of the U.S. Department of Energy (DOE), Brookhaven National
Laboratory is located in the Town of Brookhaven in Suffolk County on
Long Island, approximately 60 miles east of New York City. The BNL site
occupies about 5,300 mostly-wooded acres in Suffolk County. Many of the
Labís facilities are near the center of the site, in a developed portion
that covers about 1,700 acres. The High Flux Beam Reactor (HFBR) is located
in this central portion of the BNL property. The HFBR complex covers
approximately 13 acres.
The mission of the HFBR was to provide a source of neutrons for
multidisciplinary scientific research in materials science, chemistry,
biology, and physics. The HFBR achieved criticality on October 31, 1965. The
reactor was originally designed for operation at a power level of 40
megawatts (MW). In addition to its external beams of neutrons, seven sample
irradiation thimbles for neutron activation experiments were provided. In
1982, an equipment upgrade allowed operations at 60 MW. The reactor was shut
down in 1989 to analyze the safety impact of a hypothetical loss-of-coolant
accident. It was restarted in 1991 at 30 MW. The HFBR was shut down for
routine maintenance and refueling in 1996 when 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 1999, the DOE
decided to permanently shut down the HFBR.
The HFBR Complex
HFBR complex consists of multiple structures and systems that were necessary
to operate and maintain the reactor. The most recognizable features of the
complex are the domed reactor confinement building and the distinctive
red-and-white stack (at right).
Portions of the complex building structures, systems, and components, some
of which are underground, are contaminated with radionuclides and chemicals
as a result of previous HFBR and Brookhaven Graphite Research Reactor (BGRR)
operations. A number of actions have been taken to remove contaminated
structures, hazardous materials, and contaminated equipment and components
to prepare for permanent decommissioning. The remaining structures and
systems are described below.
The High Flux Beam Reactor complex (in gray) includes
Building 704 Fan House; Building 705 Stack; Building 750 Confinement
Bldg; Building 751 Cold Neutron Facility; Building 802 Fan House and Tritiated Water Evaporation Facility.
Building 750, HFBR Confinement Building
Building 750, which houses the HFBR, is a hemispherical dome. It is
the superstructure of the confinement building. The structure is
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 ft. 8 inches. The base is 22 ft. 4 in. high and rests
on a bedplate 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 contains the reactor and
biological shield and is 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 (shown at right) was for scientific users. The
reactor biological shield which surrounds the reactor occupies 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. Access to the confinement building is provided
by four airlocks: a personnel airlock; a forklift airlock; and two tractor
trailer airlocks, one located on the experimental level and one on the
equipment level. Most of the HFBRís systems have been put into a
lay-up condition. Only the building heating, ventilation, fire
suppression, and cooling (HVAC) systems remain in service.
Reactor and Biological Shield
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/reflector and primary coolant. The reactor
vessel was fabricated from aluminum alloy and contained the active
core, reflector, and control rods. The vessel consists of an 82 in.
spherical section welded to a 46 in. cylinder. The overall height of the
vessel assembly is 24.75 ft. There are nine horizontal beam entry
tubes that are integral parts of the vesselís spherical section. The
core region provided space and access for 16 experimental facilities.
The biological shield (diagram below) surrounds both the reactor vessel and the
9 in. thick thermal shield. The biological shield is 8 ft. thick and
consists of an inner and outer steel shell filled with high-density concrete
which also serves as an essential component of the structural integrity of
the confinement building. The thermal shield is a carbon steel shell
lined with lead.
There are 16 control rod blades (CRBs, below, right) within
the reactor vessel. They are separated into main and auxiliary groups,
each containing eight CRBs. The CRBs operated in the reflector region
just outside the core. The CRBs are angle-shaped in cross-section and
are made of stainless steel, encapsulating europium oxide and dysprosium
Building 704, Fan House
The fan house was initially constructed to provide primary and secondary
cooling air for the BGRR. It encloses the BGRR discharge plenum and
also houses the electrical switchgear and the normal and emergency power
batteries for the HFBR. This switchgear also provides normal power to
Bldgs. 703 and 701 and provides the pathway for the HFBR Bldg. 750 exhaust
through underground ductwork and filter banks.
Building 705, Stack
The 100-meter tall stack was initially constructed to provide for
elevated exhaust for the BGRR primary and secondary cooling air.
Subsequently, additional building exhaust systems were connected to the
stack. Currently, exhaust streams from Bldgs. 801 and Bldg. 750, the
HFBR confinement building, are still connected to the stack.
Building 802 Ė Fan House
(at right) houses the fans and equipment that provided the
building exhaust flow for Bldgs. 801, 815, and 830. It also housed the
equipment for evaporation of low-level tritiated water.
Underground Stack Ventilation Ducts and Lines
The underground stack ventilation ducts are the interconnecting ducts
from Bldg. 750 and Bldgs. 801 and 802. Short sections of ducts from
Bldgs. 901 and 701 are also included.
Last Modified: May 22, 2009
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