S.A.Robotics

Client	Brookhaven Science Associates
Facility	Brookhaven Graphite Research Reactor
Location	Upton, NY

Excavator Gantry Equipment

A gantry mounted remote manipulator or excavator-like machine was designed, fabricated, tested and installed by S. A. Technology and fitted with special tools on an independent rails system above the Bioshield. This graphite mining machine was designed and tooled to mine out the graphite moderator, deploy a sheer for rod cutting and removal, deploy a thermal cutting robot capable of remotely cutting the inside bioshield liner and support steel and use a hydraulic demolition hammer attachment to remove the concrete filler and sheer the steel that ties the Bioshield liners together. The graphite mining manipulator is supported by a structural steel system 40 feet off the reactor main floor. The manipulator rides on a set of rails which spans the reactor bioshield. A gantry arrangement with a 50 foot long bridge and trolley allows the manipulator to travel in X-Y (E-W, N-S) directions above the reactor cavity. The excavator can then rotate and reach down into the reactor cavity to perform the mining operations. The equipment is remotely operated from a control room via camera coverage of the entire operation.

Support Crane

A dedicated 10 ton crane was designed and installed by SAT and rides on a second set of rails outside those of the excavator gantry. This crane was used to remove the concrete roof plugs on the reactor, perform maintenance of the equipment and deploy a soil sack inside a lift fixture into the reactor cavity. The lift fixture was designed to support the soil sacks, allow it to be loaded with material and then be lowered down into an IP-1 container staged on the north side of the reactor at floor/grade level. The lift fixture support rods are slid out, releasing the sack into the container and then pulled back up out of the container.

Structural Steel Support System

The structural steel system that supports the operating equipment 40 feet off the deck is designed to support a dead load of 70 tons along with the dynamic loading that the equipment creates while mining graphite or lifting loads with the crane. The system was designed by Burns & Roe Engineering as a subcontractor to SAT. This system will also support the dynamic loads that are created when the bioshield concrete is hammered out. This system had to be neatly fit into the 60 plus year old reactor high bay building that house the reactor. Additional challenges in designing this system involved maintaining all the large support girders, 50 foot long equipment bridge and major equipment individual weights below 10 tons so that the existing reactor building 10 ton crane (not the new support crane) could lift the members. Added structural challenges involved finding and analyzing footings to support the structural steel system.  With below ground ductwork and limited grade beams the project was forced to do things like modify an existing elevator shaft into one of the columns and hang a support truss off one of the reactor building crane girders.  Another significant challenge was to design and install a support system that was completely independent of the bioshield structure.  During graphite removal the bioshield is credited as a containment system (SSC) for the moderator.  Eventually the equipment will be used to remotely demolish the bioshield from the inside out undermining the Bioshield as a support structure that can be credited in any way.

Contamination Control Enclosure

The entire excavating system, support crane, waste load-out system, reactor roof and the entire north side of the reactor is housed in the largest Contamination Control Enclosure (CCE) ever built by Lancs Industries. The support frame for this tent had to be designed to support the massive walls of this containment under a negative air pressure. Airlocks on the each end of the north side waste load-out area enable waste crates, tooling and personnel to enter the area and leave while negative pressure is maintained in the containment and support the radiological controls necessary when handling contaminated material.

Ventilation System

The containment system is brought under a negative pressure and the atmosphere turned over in the space for contamination control purposes by four 6000 CFM air movers. The HEPA filter banks for this ventilation system are located in the reactor high bay building. The fans for the system are located in a fan house (converted cargo container) outside the high bay. The flow path draws air into the containment through dampers, down through the reactor cavity opening, out of the bioshield through a plenum attached to existing fuel charging penetrations on the south side of the reactor block, through the HEPA filter banks, out of the building through the fans and exhausts through a stack that runs up the outside of the high bay building. The exhaust is monitored by instrumentation and probes which are inserted into the stack. Redundancy in the fan units allow for filter change outs and fan maintenance while the containment is maintained under negative pressure.

Control Room, Hydraulics & Fixative Spray System

The operation of the excavator, crane and the ventilation system is primarily accomplished from a control room located on the east side of the reactor. An actual Gradall excavator control chair was outfitted with additional controls for added tool features. The remote video system provides multiple views of the reactor cavity and displays them on monitors in front of the operator. Another panel and radio frequency belly pack are used to operate the crane with added camera coverage and video display. Two of the ventilation fans are operated from a remote panel with pressure indication in the control room to allow for negative pressure adjustments and flow adjustments within the CCE atmosphere. A fixative spray system provides contamination control fixative up through the excavator gantry arm through nozzles on the primary tools to spray down the pile and keep dust down. This system along with the primary and backup hydraulic skids are located on the east side of the reactor building.

Description Work and Operations

As of the date this was written (4/28/10), this excavator/mining equipment was being used to remove the graphite blocks from the pile and load them into the supersacks. 95% of the pile was safely removed in just a few months. The supersacks are supported and positioned in the reactor cavity by the lift fixture attached to the crane. After loaded the lift fixtures deploy the sack down and into the permanent waste crate staged on the north side of the main floor. The sack is released into the crate and the lift fixture pulled back out of the crate. The lift fixture is prepared with a new sack while the crate is lidded. The crate is surveyed and removed from the waste load out area by a fork truck through the air locks. When tie rods and alignment rods need to be size reduced the shear attachment is installed on the excavator arm and positions down into the cavity to shear the rods and load them into the lift fixture. They will then be placed inside the IP-1 crates like the graphite for shipment to DOE’s Nevada Test Site for disposal. The pile is sprayed down with fixative as layers of graphite are removed to keep dust and contamination under control.