Bill Randall, J. Steel, R. Jones,C. Ward, G. Hovis, E. Kriikku, and K. Peterson
Westinghouse Savannah River Company
Aiken, SC 29808

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The Plutonium Immobilization Plant (PIP) will encapsulate plutonium in ceramic pucks and seal the pucks inside welded cans. Remote equipment will place these cans in magazines and the magazines in a Defense Waste Processing Facility (DWPF) canister. The DWPF will fill the canister with glass for permanent storage. This report discusses the Plutonium Immobilization Can Loading conceptual design for the 13 Metric Ton (MT) PIP throughput case. This report includes a process block diagram, process description, and preliminary equipment specifications and documents the changes to the original can loading concept documented in previous reports [4,5].

The Plutonium Immobilization Plant design will minimize operator exposure and prevent the spread of contamination. To accomplish these goals, a system must package contaminated materials in clean containers and not release contamination.

The Plutonium Immobilization Plant must produce approximately 1 loaded Defense Waste Processing Facility (DWPF) canister per day. Assuming the ceramic pucks are 2 5/8" in diameter and 1" thick (nominal dimensions), the bagless transfer system has to load 146 560 pucks into cans per day to meet 13 MT production requirements. The can loading system must be able to automatically load at least 19 pucks per hour (8 hrs/day) into puck cans and process 7.3 puck cans per day. Remote equipment in the Canister Loading Area will load the puck cans into magazines and load the magazines into racks inside the DWPF canisters. The DWPF fills canisters with approximately 91 inches of glass and the glass must surround the puck cans, magazines, and racks.

Normal can loading system operations will be performed remotely, but maintenance and repairs will be performed manually. The can loading system design shall minimize the amount of equipment in the containment, minimize the complexity of the equipment in the containment, design the equipment for minimal maintenance, and design the equipment for glovebox repair and replacement. The remote equipment will be the first option for off-normal event recovery (such as retrieving a dropped puck), and the manual operations will be the backup option.

Attachment 1 is the Can Loading process block diagram and it shows the detailed Can Loading process steps. The process block diagram is based on the Can Loading steps contained in the Plutonium Immobilization Plant, First Stage Immobilization, Process Flow Drawing (P-203, Rev. 2, PIP DOCDR, 9/2000).

Attachment 2 shows the can loading 13 MT concept and the following paragraphs describe the can loading processes.

New cans, manually pre-loaded with plugs, are placed in a rack external to the bagless transfer enclosure. The magnetically coupled transport cart brings the rack of cans to the bagless transfer enclosure. The can handling robot removes the cans from the rack and places them in a storage area in the bagless transfer enclosure. The can handling robot moves a new can from storage into the empty bagless transfer can holder and then the bagless transfer system raises the can. The previous can stub is pushed by the new can into the can loading glovebox and the can loading robot places the stub on an empty tray. The empty tray and can stub leave the loading glovebox on the magnetic coupled transport cart. The stub is taken to the elevator and then to the waste handling glovebox via the Inter-Glovebox Transport System (IGTS). The can loading robot removes the plug from the new can and the loading process is initiated.

A transfer tray of pucks enters the can loading glovebox on a magnetically coupled transport cart and one of two tray staging systems lifts the transfer tray from the cart. The can loading robot (Cartesian type) uses a vacuum cup on a 40 inch pipe to remove the pucks from the transfer tray and loads twenty pucks into one of two puck cans. The cart moves the empty transfer tray from the tray staging system to the elevator. The can loading robot can removes pucks from a tray at either lift station and the cart can move one tray under a second tray at a lift station. This will allow the system to load pucks while the cart removes an empty tray and brings a new tray to the tray staging system.

When the can is fully loaded with pucks, the can loading robot then places the helium hood over the can plug. The helium hood grabs the can plug using a vacuum cup, the can loading robot places the helium hood over the full puck can, and the helium hood seals to the can. The helium hood purges the air from the can, fills the can with helium, and inserts the plug into the can. The corresponding bagless transfer system then welds the plug to the can wall, and cuts the can and plug leaving the can stub in the sphincter seal.

The bagless transfer can holder lowers the can in the bagless transfer enclosure under the can loading glovebox, and the can inspection robot surveys approximately 80% of the can exterior with an alpha probe. After the survey is complete, the can handling robot removes the can from the bagless transfer can holder, and the inspection robot surveys the top, bottom and the remaining puck can sides. The can handling robot places the contamination free puck can in the helium bell jar leak detector. The leak detector will ensure the weld is leak tight. After the leak test is complete, the can handling robot places the can in a can holder assembly on the magnetically coupled transport cart and the can leaves the bagless transfer enclosure.

In addition to the helium leak test, operators will use cameras and welder feedback to determine can weld failures. Conceptual details of the camera inspection system are under development. The bagless transfer machine will push cans that experience weld failures up into the sphincter seal exposing the top 3 inches of the can above the sphincter seal. The reject can cutter, not shown in attachment 2, will move over the exposed can and cut the failed can open near the top. This cut will be in the void space above the pucks. The can loading robot will remove the can top and the pucks from the failed can. If possible, the can loading robot will put pucks from the failed can into a new can in the other bagless transfer unit. Puck will otherwise be replaced on their original transfer tray. The bagless transfer can holder then pushes the empty failed can further up through the sphincter seal to make room for a new can underneath it. The can handling robot will place a new can in the bagless transfer can holder and the can holder will use the new can to push the failed can into the can loading glovebox. The transport carts will be used to remove any pucks and cut can pieces from the can loading glovebox and all loaded cans from the bagless transfer enclosure. The cut can pieces and any can stubs will be sent to the waste handling glovebox. These items will have sharp edges and will require special handling procedures (use of burr covers, etc.) if they are manually processed. Operators will manually perform any system maintenance including sphincter seal replacement. The can handling robot will be used for recovery from offnormal events where feasible, with the balance of recovery operations being performed manually.

The can handling robot will place cans that fail the survey in the bagless transfer can holder. The bagless transfer can holder will push the failed can up into the sphincter seal and this will push the stub into the can loading glovebox. The can loading robot will place the stub on an empty tray and the can handling robot will load a new can into the bagless transfer can holder. The bagless transfer can holder will push the failed can into the sphincter seal exposing the top 3 inches of the can above the sphincter seal. The can loading robot will process these reject cans in a similar manner as the weld failure cans described above.

The can handling robot will place cans that fail the leak check in the bagless transfer can holder. The bagless transfer can holder will push the failed can up into the sphincter seal and this will push the stub into the can loading glovebox. The can loading robot will place the stub on an empty tray and the can handling robot will load a new can into the bagless transfer can holder. The bagless transfer can holder will push the failed can into the sphincter seal exposing the top 3 inches of the can above the sphincter seal. The can loading robot will process these reject cans in a similar manner as the weld failure cans described above.

Table 1 shows the can loading equipment list and potential vendors for each equipment item. The following paragraphs describe the preliminary specifications for each.

The can loading glovebox shown in Attachment 2 will allow sintered pucks to enter on transfer trays through an airlock, contain the equipment to load pucks into cans, and support the bagless transfer sphincter seal. The maximum glovebox envelope will be approximately 60 inches long, 48 inches wide, and 60 inches high. The lower section of the glovebox (below the bridge section of the can loading robot) will be narrowed to 38 inches to increase accessibility. The glovebox requires several gloveports, removable panels, and extensive shielding. The glovebox will be fabricated from 304 stainless steel, lead, and water extended polyester (WEP). The glovebox will be designed to hold a slight negative pressure, approximately 0.5 inches of water, and conform to appropriate American Glovebox Society (AGS-1994-G001, Guidelines for Gloveboxes) and SRS glovebox standards.

The magnetically coupled (acme screw driven) tray elevator will raise and lower transfer trays from the transport cart to the overhead tray transport system. Transfer tray concepts hold up to 16 one pound pucks. The tray will weigh approximately 10 pounds, so the tray elevator must be able to lift a 26 pound payload. The elevator size will be driven by the transfer tray size. The transfer tray is approximately 12 inches by 12 inches, so the elevator shaft will be about 16 inches by 20 inches. These dimensions provide space for the elevator acme screw and guide rails. The tray elevator parts will be fabricated from 304 stainless steel where ever possible and all moving parts will be covered when possible. The magnetically coupled elevator design will allow the drive motor to be outside the containment for easier maintenance and cleaning.

The magnetically coupled transport cart system will move puck transfer trays from the IGTS tray elevator to the tray staging system in the can loading glovebox. Transfer tray concepts hold up to 16 one pound pucks, and the tray will weigh approximately 10 pounds, so the transport cart must be able to handle a 26 pound payload. The transport cart size will be driven by the transfer tray size. The transfer tray is approximately 12 inches by 12 inches, so the transport cart will be about 8 inches by 8 inches. The transport cart parts will be fabricated from 304 stainless steel where ever possible. The magnetically coupled cart design will allow the drive system and other components to be outside (and under) the containment for easy accessibility. The passive cart and cart rails will be the only system parts inside the glovebox.

The transfer tray staging system will consist of two tray lift stations. Each station will lift a puck transfer tray from the transport cart to stage the tray. The can loading robot can access sintered pucks on either tray and the cart can move one tray under a second tray at a lift station. Transfer tray concepts hold up to 16 one pound sintered pucks, and the tray will weigh approximately 10 pounds, so the tray staging lift units must be able to lift a 26 pound payload. The tray lift station size will be driven by the transfer tray size. The transfer tray is approximately 12 inches by 12 inches, so the tray lift stations will be about 12 inches long by 18 inches wide by 10 inches tall. The lift height will provide sufficient clearance for the cart carrying a tray to move under a lifted tray. The tray staging system parts will be fabricated from 304 stainless steel wherever possible and all moving parts will be covered when possible to act as operator guarding and to simplify clean up activities. The magnetically coupled lift station design will allow the drive motors to be outside the containment for easier maintenance and cleaning.

The can loading robot, a Cartesian type, will use a puck lifting tool to lift pucks from the transport trays and place them in the puck can. The can loading robot will also handle can stubs, reject cans, can cutter, and the helium hood. The robot’s maximum payload will be the 30 pound can cutter. The can loading robot requires three degrees of freedom, X - Y - Z, and a gripper. The X axis will provide 52 inches of travel, the Y axis will provide 28 inches of travel, and the Z axis (up and down) will provide 44 inches of travel. These travel limits will allow the can loading robot to fit inside the 60 inch long by 38/48 inch wide by 60 inch tall can loading glovebox. Each axis requires a repeatability of +/- 0.025 inches and a velocity range from 0 to 10 inches/second.

The gripper will lift the following items; the puck lifting tool, can cutter, helium hood, puck cans, and can stubs. Each item has a 3 inch outer diameter or will have a 3 inch outer diameter lifting point, so the gripper will always grab the same shape. The can loading robot and gripper parts will be fabricated from 304 stainless steel where ever possible and all moving parts will be covered when possible to act as operator guarding and to simplify clean up activities. If possible, the internal cavities will be slightly pressurized to help prevent contamination from entering the robot and gripper.

The helium hood will fill the puck can with helium and insert the can plug. The helium hood will perform the following operational steps. First, the hood will grab the can plug with a vacuum cup. Second, the can loading robot will place the hood on the puck can. Third, the helium hood will seal to the puck can and pull a vacuum on the puck can. Fourth, the hood will fill the puck can with helium. Fifth, the hood will place the can plug into the can. The FB-Line bagless transfer system procedure indicates three iterations for helium backfilling, each consisting of pulling a vacuum to 20 inches of mercury on the product can and backfilling with +3 psi of helium. The can loading helium hood will be able to duplicate this. The helium hood requires position feedback (+/- 0.05 inches) and force control on the can plug insertion actuator to ensure the plug is inserted to the proper position. The hood requires an umbilical cord to supply the vacuum lines, helium lines, and plug insertion actuator power and position feedback cables. The helium hood parts will be fabricated from 304 stainless steel where ever possible.

The puck lifting tool will be used by the can loading robot to pick up sintered pucks and place them inside the puck can. The lifting tool will carry one puck at a time, so the maximum payload will be approximately one pound. The lifting tool will be a hollow pipe approximately 44 inches long and the lower 30 inches must be less than 2.25 inches in diameter. The lifting tool lower 30 inches must fit inside the 2.88 inch inner diameter by 30 inch long puck can. The lifting tool will have a vacuum cup on the lower end and a 3 inch diameter grab point on the top end. The 3 inch diameter section will allow the robot gripper to firmly hold the tool. This grab point will be the top 4 inches of the tool and will never enter the puck can. The puck lifting tool will be fabricated from 304 stainless steel. The lifting tool requires a vacuum line for the vacuum cup. The vacuum line is automatically connected to the puck lifting tool through the can loading robot gripper.

The vision system will use a "coarse" camera to find pucks on the tray and send the puck locations to the can loading robot. This information will be used to acquire the pucks using the puck lifting tool. The vision system will also use a "fine" camera to precisely locate pucks on the puck lifting tool after they have been acquired and send the puck location to the can loading robot. This will allow the can loading robot to accurately place the pucks within the can ID. The vision system will use commercially available cameras, software, and computer hardware. The vision system cameras will be mounted outside the can loading glovebox to facilitate camera maintenance and reduce contamination potential.

The failed can cutter will cut open cans that fail in the welder or fail the leak check. Failed cans will be pushed up into the sphincter seal exposing the top 3 inches of the can above the seal and the can loading robot will place the can cutter over the exposed can. The can cutter will be a commercially available pipe cutter sized to cut 3 inch outer diameter thin walled pipe. The can cutter parts will be fabricated from 304 stainless steel where ever possible and all moving parts will be covered when possible. The can cutter will require an umbilical cord for power.

The bagless transfer enclosure will contain two bagless transfer systems, the inspection robot, the can handling robot, the helium leak detector chamber, two alpha probes, and a puck can transport cart. The enclosure will be sealed and vented during normal operations, but it will have an automated door to allow filled cans to leave on the transport cart and several manual doors for maintenance. The enclosure is sealed to prevent contamination spread in the event the bagless transfer sphincter seal fails or if the bagless transfer weld fails. The enclosure will be vented to the facility hood exhaust system and HEPA filters will isolate the enclosure from the hood exhaust duct work. It will be maintained at a pressure lower than ambient, but higher than that of the can loading glovebox, to prevent possible contamination migration. The enclosure will be approximately 120 inches long, 38 inches wide, and 60 inches high. The enclosure will be fabricated from 304 stainless steel.

The can welders will weld the can plug to the can wall from outside the can. The FB-Line bagless transfer system uses a commercially available TIG welder by Arc Machines Inc., as will the can loading bagless transfer welder. The welder will be sized for a 3 inch outer diameter can and the welding head must be compatible with the 0.040 inch thick 304L stainless steel can wall and 0.125 inch thick 304L stainless steel hollow plug. Camera systems may be employed at the welder to inspect for weld defects, or at the inspection robot.

The can cutters will cut the puck can and hollow plug in the weld area to separate the can of pucks from the stub. The FB-Line bagless transfer system uses a commercially available Tri-Tool Inc. pipe cutter, as will the can loading bagless transfer cutter. The cutters will be sized to clamp around the 3 inch outer diameter cans and cut through the 0.040 inch thick can wall and the 0.125 inch thick hollow plug wall. The can and plug will be fabricated from 304L stainless steel.

The can holders will support, raise, and lower the puck cans while they are in the bagless transfer system. The can holders will also hold and swing the puck can while the inspection robot surveys the can for contamination. The can holder maximum payload will be a filled 25 pound puck can plus the force required to push the can through the sphincter seal. The can holders will be shaped like a cup and sized to hold a 3 inch outer diameter can. The holders will have enough clearance to allow the can handling robot to remove the cans from the can holder. The can holder parts will be fabricated from 304 stainless steel wherever possible.

The inspection robot will survey puck cans with two detectors; one for the puck can sides and one for can top and bottom. The inspection robot maximum payload will be the heavier of the two survey tools. The inspection robot requires a minimum of 6 degrees of freedom (DOF) and a gripper. The six DOFs allow the inspection robot to maneuver the survey tools over the cylindrical can. The inspection robot will need a minimum radial reach of 20 inches. This will allow it to reach a puck can in the bagless transfer can holder and the survey tools. The inspection robot requires a repeatability of +/- 0.020 inches or better.

The gripper will manipulate the survey tools. The inspection robot and gripper parts will be fabricated from 304 stainless steel wherever possible and all moving parts will be covered when possible to act as operator guarding and to simplify clean up activities. If possible, the internal cavities will be slightly pressurized to help prevent contamination from entering the robot and gripper. A camera system may be employed at the Inspection Robot to inspect for weld defects if inspections are not being performed at the Can Welders.

The alpha probes will analyze the loaded puck can surface for alpha contamination. The probes will be commercially available or custom built probes from a commercial company.

The can handling robot will load and unload puck cans in the bagless transfer system, load and unload cans in the leak detector, load and unload empty cans in a can holder assembly, and place puck cans on the transport cart. The can handling robot maximum payload will be the 25 pound fully loaded puck can. It requires 3 degrees of freedom (DOF) and a gripper. The three DOFs allow the robot to load and unload puck cans at various stations. The robot must be able to reach all the can stations inside the bagless transfer enclosure. The can handling robot requires a repeatability of +/- 0.020 inches or better. The gripper will hold 3 inch diameter puck cans.

The helium leak detector chamber will perform leak checks on the puck cans after they are welded by the bagless transfer system. This will include volumetric expansion and helium tests. The chamber will be sized to hold the 3 inch outer diameter by 20 inch long (nominally) puck can. The chamber will be opened and closed by dedicated actuators. The chamber will open so that the can robot can easily load and unload puck cans in the chamber. The chamber must seal well enough to perform hundreds of helium leak checks before the seal system fails. The chamber and associated pump system will pull a vacuum sufficient for the helium detector.

The helium detector will analyze the gases from the helium leak detector chamber. If helium is detected above a specified leak rate, the can will fail the leak/weld inspection. The detector will be a commercially available mass spectrometer calibrated for helium (the same as that used in FB-Line). The detector will be located outside the bagless transfer enclosure. The helium detector (and all other leak test apparatus) and leak test procedures will conform to the standards specified in ASTM E499-90 method B.

The magnetic coupled transport cart will remove full puck cans from the bagless transfer enclosure and bring empty cans into the enclosure. The cans will be placed in a special rack and the transport cart will move this rack. The rack will hold 3 cans in the vertical position. A full puck can weighs about 25 pounds, the rack will weigh approximately 20 pounds, so the transport cart must be able to handle a 100 pound payload. The rack and transport cart parts will be fabricated from 304 stainless steel wherever possible. The magnetically coupled cart design will allow the drive system and other components to be installed outside (and under) the enclosure for easy accessibility. The passive cart and cart rails will be the only system parts inside the enclosure.

The can loading control system will interface on a high level with other facility computer systems such as; the Material Control & Accountability system and the inter-glovebox transport system. The control system will interface on a high level with the can loading robot, inspection robot, and the can robot controllers. The control system will interface on a low level with the tray elevator, transport carts, airlock doors, lift stations, etc. A high-level computer interface is the exchange of complex or multi-step commands such as "send more pucks" or "load a new can". A low level computer interface is the exchange of simple or single step commands such as "run the cart motor clockwise" or "stop the cart motor". The can loading control system will allow single point of control for the entire system.

It is proposed that the weight and dimensions of each puck be acquired just prior to placing them in the can. This data would complement that which is already generated by the tracking of each transfer tray (required by MC&A), and verify the specific location of each puck from when they were originally placed on the transfer tray. The individual puck weights could be combined to establish the total weight of pucks in each can and the puck diameter would verify that each puck is small enough to be placed in the can. The puck height would determine where to release each puck inside the can without contacting the puck below it before release and without dropping it a long distance. The individual puck heights would also be summed to determine how many pucks can be placed in each can.

This inspection may be accomplished with equipment very similar to the puck inspection stations for green pucks and sintered pucks. The station would be close to, and likely between, the bagless transfer stations in the can loading glovebox.

This report documents the changes to the PIP can loading conceptual design for the PIP 13 MT throughput case. The Can Loading Process Block Diagram (Attachment 1) details the required can loading steps and is based on the Plutonium Immobilization Plant, First Stage Immobilization, Process Flow Drawing. Attachment 2 shows the can loading layout and the process description discusses the steps required to load ceramic pucks in puck cans and inspect cans after they are welded. The equipment section describes the preliminary equipment specifications for each piece of equipment in the design.

1. Plutonium Immobilization Can Loading Puck Can Size Evaluation (U). USDOE Report WSRC-TR-98-00051, Savannah River Site, Aiken, SC 29808 (2/13/98)
2. Plutonium Immobilization Can Loading Equipment Review (U). USDOE Report WSRC-TR-98-00164, Savannah River Site, Aiken, SC 29808 (5/1/98)
3. Plutonium Immobilization Preliminary Can Loading Concepts (U). USDOE Report WSRC-TR-98-00165, Savannah River Site, Aiken, SC 29808 (5/29/98)
4. Plutonium Immobilization Can Loading Conceptual Design (U). USDOE Report WSRC -TR-98-00229, Savannah River Site, Aiken, SC 29808 (7/1/98)
5. Plutonium Immobilization Can Loading Preliminary Specifications (U). USDOE Report WSRC-TR-98-00291, Savannah River Site, Aiken, SC 29808 (9/1/98)
6. Plutonium Immobilization Can Loading FY98 Year End Design Report (U). USDOE Report WSRC-TR-98-00310, Savannah River Site, Aiken, SC 29808 (9/18/98)
7. Plutonium Immobilization Can Loading FY99 Component Test Report (U). USDOE Report WSRC-TR-99-00318, Savannah River Site, Aiken, SC 29808 (9/30/99)

Attachment 1 - Can Loading Process Block Diagram

Attachment 2 – Can Loading Conceptual Layout