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tions and in the event of an accident. The ease of monitoring water movements and exercising necessary controls thereover, in the case of an accident, is assured by the favorable conditions existent on the plateau in which these waste facilities will be located.
8. DESCRIPTION OF FACILITIES
Measures to assure plant protection have been taken. The plant site area is approximately in the center of the 3.331-acre Riceville site and contains about 230 acres. The overall site will be fenced with barbed wire farm fence and conspicuously posted. The plant site area will be fenced with 6-foot chain link fence with three strands of barbed wire on top and it, too, will be conspicuously posted. Only authorized personnel will be allowed inside the plant site area through a single guarded entry. The public will be permitted to use the roads which go through the site, but they will be posted at entrances and along the right-of-ways warning the public not to leave the roadways. The layout of facilities in the plant site area is shown in figure 3.1 of the safety analysis. Auxiliary facilities, as shown therein, include the waste tank farm, burial ground, seepage basin, and warehouse.
The process building, shown in plan in figure 3.56 of the safety analysis, contains about 40,000 square feet of gross floor area. The primary process areas are arranged in a with the fuel introduced into the right end of the and purified products removed from the other end. Laboratories, lavatory facilities, washrooms, utilities, and related service areas have been provided. Maintenance shops are in a separate adjacent building.
The fuel receiving and storage area contains washdown facilities, cask storage, cask decontamination pit, cask unloading pool, and the fuel storage pool. Casks may be brought into the receiving area by truck or by rail. There is a 100-ton overhead crane servicing this area. To the left of the receiving area is the cask unloading pool which is 26 feet by 24 feet by 45 feet deep. The pool is filled with demineralized water to a depth such that there is a minimum of 11 feet of water shielding over the longest fuel element as it is removed from the cask. The storage pool is further to the left. It has dimensions of 75 feet by 40 feet by 29 feet deep. The fuel is stored in a rack designed so that no fuel element may come within 12 inches of another. Fuel elements are removed from the storage pool and taken into the process mechanical cell (PMC) by means of an underwater transfer conveyor.
The PMO, the area in which the processing of individual fuel elements is begun, is a cell 16 feet wide by 54 feet long by 24 feet high. The walls of the cell are 6 feet of concrete containing six glass viewing windows. The entire area is serviced by two 2-ton cranes, a .power-manipulator and four pairs of master-slave manipulators. At the end of the cell, which forms the intersection of the PMC and the chemical process cell (CPC), there is a decontamination area into which equipment from either the PMC or the CPC can be brought for decontamination and maintenance. The cell has openings in the floor to underground tunnels which lead to the CPC and the scrap removal hatch. There is also an opening in the ceiling which connects to a small experimental cell located above the PMC.
At right angles to the PMC and connected to it by means of the decontamination area is the CPC, a remote maintenance cell. This cell contains the dissolvers and evaporators which may be expected to require frequent maintenance and replacement. The cell is 21 feet wide by 89 feet long by 45 feet high with concrete walls 6 feet thick. The entire cell is serviced by a 10-ton remotely operated crane and by a power manipulator, capable of replacing remotely any piece of equipment in this cell. Except for the transfer of fuel into the cell from the PMC and the return of leached hulls, transfers into and out of this cell are liquids flowing through pipes into a warm equipment aisle (WBA).
Adjoining the CPC, and at right angles to it, is an area which is maintained by contact methods. It is divided into five cells. In the first three the solvent extraction columns and their appurtenances are installed. In the fourth and fifth are installed the final purification and concentration equipment for the products. The overall length of these cells is 97 feet, the widths are 17, 20.5, 21.5, 21.5, and 39.5 feet, and the heights are 54 feet. Shielding walls are 5 feet 3 inches concrete for the first cell and step down to 3 feet 6 inches in the second cell and 3 feet in the remainder. Access is provided through roof plugs. There are no solid transfers in or out of these cells. Liquid transfers are made through pipes in the cell walls or into the WEA.
In addition to the foregoing areas which are directly concerned with the mainline process, there are a number of supporting areas and functions. Operating aisles are located on both sides of the PMC and along one side of the CPO and the contact cells. Controls and instruments for much of the equipment are lo cated in these aisles. Essentially all of the flow adjustment and effectuation of fluid transfers is done from these aisles. Underneath the interior operating aisles are sample aisles, pulser pump aisles, and the WEA. In the pulser pump and warm equipment aisles there are a series of shielding cubicles located below the floor level of the aisle. Each cubicle has a removable shield cover. All mechanical equipment such as pumps and pulsers are to be brought out of the cells and placed in these shielded cubicles in order to simplify the maintenance thereof.
Inside the NL on three levels are located assorted service facilities such as offices, laboratories, washrooms, locker rooms, health physics facilities, etc. Two of the levels are largely taken up with analytical facilities including five shielded hot caves.
4. DETAILED PROCESS DESCRIPTION Basic process
The plant is a multipurpose plant capable of processing any type of fuel elements from which the fuel proper can be reduced to a nitric acid solution. This includes all but one of the presently contemplated fuels from private nuclear powerplants (graphite matrix fuels). No fuel will be processed before it has been cooled for 150 days. The baseline process is a Purex solvent extraction system designed for processing of low enriched UO, in stainless steel or zirconium alloy tubes with a maximum throughput of 1,000 kilograms of uranium per day. In addition, there will be
1. A head dissolution treatment for the dissolution of zirconium clad fuels in HNO HF mixtures, permitting a throughput of 600 kilograms of zirconium per day. Dissolution is performed in stainless steel dissolvers with controlled additions of HF and HNO3. Aluminum nitrate is added to permit extraction of the uranium and to minimize corrosion. Stainless steel tankage will be provided for storing the wastes in acidic condition.
2. A direct nitric acid dissolution process for aluminum-uranium or molybdenum-uranium alloy fuels or for uranium itself.
3. At a later date equipment will be added to process stainless steel
cermet fuels and those in which sodium is used as a heat transfer agent. Receipt and storage
The fuel is received in shielded casks in the washdown area. After temperature reading, sampling of cask coolants and purging of gases into the ventilation system, the cask is placed under water in the 45-foot-deep unloading pool by a hand-operated overhead crane. The fuel is removed and placed in storage baskets by remotely operated equipment and the cask is transferred to a decontamination pit. The storage baskets are transferred by the storage pool crane to the fuel storage pool and placed in safe geometry racks. Any ruptured elements will be stored in sealed canisters. Mechanical processing
When the fuel is ready to be processed, it is transferred by the storage pool crane to the underwater process pool from where it is transferred through a conveyor and crane to the process mechanical cell. It is removed from the basket by remote equipment and dried. The end hardware is then cut off and the fuel pushed out of its casing. After inspection, it is chopped into small pieces in the bundle shear. This operation may be carried out under an inert atmosphere. The resulting pieces of fuel are collected in chopped fuel canisters. Then the chopped fuel canisters are removed to the chemical processing cell on a transfer cart through an airlock. Chemical processing
In the chemical processing cell, the chopped fuel canisters are placed into one of the dissolver barrels. Nitric acid and water are metered into the dissolver from the solution makeup area so that the final solution contains no more than 7.5 grams per liter of U235, a critically safe concentration in all geometries and quantities. Complete dissolution is expected to take about 12 hours. The offgas treatment includes a downdraft condenser on the dissolver, a secondary condenser, a scrubber, iodine removal on a silver reactor, and filtration through parallel filters. The off-gas is then added to the general ventilation system for further filtration before discharge to the stack.
When the dissolution of the fuel is complete, the solution is cooled and jetted to a 304-L stainless steel accountability and feed adjustment tank. The dissolver is then heated to dry off the bulls, which are returned to the process mechanical cell. The hulls are inspected and packaged and sent to the solid waste storage area. The accountability and feed adjustment tank is equipped with heating coils, a condenser, air sparger, liquid level and specific gravity measurement, circulating sampler, and temperature measurement. After analysis and adjustment of the concentration and acidity of the feed, the fuel is jetted to the partition cycle feed tank from which it is fed to the extraction columns. Solvent extraction
Solvent extraction is done by a Purex-type process, which is performed in the contact process area. The baseline fuel is put through a partition cycle, in which a TBP-kerosene solvent is used to extract the uranium and plutonium from the feed stream, leaving the bulk of the fission products(> than 99.9 percent) in an aqueous stream which becomes the major fission product waste stream of the plant. The plutonium and uranium are also separated in this first extraction cycle into two separate, partially decontaminated, aqueous product streams.
These two product streams are then separately put through additional solvent extraction cycles to complete the removal of remaining fission products.
The uranium and plutonium product streams are first collected in feed conditioner tanks for sampling, analysis, and adjustment of acid concentration. The streams are then put through additional solvent extraction cycles in which the product is extracted into an organic phase in one column and then returned to an aqueous prodụct stream in a second column. The uranium stream goes through two such cycles and the plutonium through one. Product purification and concentration
The uranium product stream from solvent extraction is collected in a product evaporator feed tank. For highly enriched fuels this solution is fed directly to silica gel beds. For low-enriched fuels the solution is concentrated before being absorbed on the silica gel beds. Two evaporators are provided, one for lowenriched fuels, the other for fully enriched fuels. Fully enriched fuel solutions are concentrated after the silica gel treatment. The uranium product solutions are collected and stored in stainless steel tanks containing sufficient fixed poison so that they are critically safe under all conditions. Samples are taken from these tanks to determine quantity and quality of the product. For shipment, the low-enriched product solution is weighted out into a tank truck. The highly enriched solution is metered into geometrically safe shipping containers which are shipped in bird cages.
The plutonium product stream is collected in an ion exchange conditioner tank from which it is pumped into one of three anion exchange columns for concentration and final decontamination. It is eluted from the columns and evaporated in a titanium vessel. The condensate is pumped back to the feed adjustment tank and the concentrate is collected in one of three plutonium storage tanks, from which it is packaged for shipment. All of the packaging and shipping equipment is enclosed in separately ventilated glove boxes. The shipping bottles are placed in secondary containers and stored in the product storage area in bird cages awaiting shipment, Solvent recovery
The plant is designed to reuse the TBP-kerosene solvent, which must be cleaned of fission products prior to reuse. To accomplish this, the solvent is first washed with sodium carbonate and then with dilute nitric acid.
All of the aqueous waste streams will contain nitric acid which will be recovered to reduce the solid loading on the waste tanks. Acid recovery is accomplished through the use of two waste evaporators following which the acid is subjected to an acid fractionation step to concentrate it into a reusable condition. Rework system
All waste streams will be sampled and analyzed prior to being discarded to the waste disposal system. In the event that the product in the waste stream is above specification, facilities are provided to rework the wastes. They are recycled through a feed tank and a rework evaporator. The bottoms from this evaporator are pumped back to the feed adjustment tank to be subjected to further solvent extraction, Waste handling
In this plant, tankage is provided for the containment of all of the process wastes both high and low level. These come from the bottoms of the high level and low level evaporators respectively. These two types of wastes are stored together in a single tank. While the inclusion of the low level wastes with the high level wastes will dilute them somewhat, the dilution is not nearly enough to render the mixture a nonboiling waste. The storage tanks used are constructed in the manner of the latest tanks built at Savannah River except that, like the waste storage tanks at Hanford, they contain no cooling coils. A spare tank is provided so that if a leak develops there will be spare tankage into which the waste from the leaking tank may be transferred. Leakage, if any occurs, should be contained in the saucer under the tank for sufficient time to permit transfer.
A. general purpose evaporator is provided in the tank farm area for reducing the volume of low level miscellaneous wastes. This is backed up by ion exchange units for the condensate. The product from this operation is expected to be essentially pure water. It normally will be discarded directly to the Buttermilk Creek system; it may be discarded there via a storage lagoon (if holdup is necessary).
Solid trash will be buried in trenches located inside the plant site area. Burial will be in the silty till of very low permability so that underground movement of radioactivity will be extremely low.
8. EQUIPMENT DESCRIPTION
The following is a brief description of major equipment pieces used in the described processes. In general, the equipment is classified either by the area in which it is located or by function. Fuel receiving and storage area
The equipment in this area is designed to permit underwater handling by remote control of the fuel elements. The major equipment pieces are
(a) Crane, 100-ton, with two auxiliary 5-ton cranes running on a mono-. rail attached to the underside of the main bridge beam. The controls are of a fail-safe type requiring manual operation.
(0) Fuel storage pool complex with water demineralized before use and continuously filtered to maintain its purity and with cleanup equipment, including a filter and demineralizer.
(c) Storage baskets perforated for cooling and drainage, made of aluminum with spacers to prevent movement of fuel in the basket during storage or movement.
(d) Movable bridge and 2-ton overhead crane which service the storage pool. The crane has a limited vertical lift to assure minimum water shielding.
(e) Storage rack for storage of fuel assemblies in the storage pool. It is designed to prevent a critical array of any configuration of any fuel.
(f) Underwater conveyor for transfer of storage baskets to the mechanical cell. The conveyor is so designed that only one basket can be handled at a time. It has an endless chain and can be controlled either at the fuel
receiving area or at the mechanical cell area. Process mechanical area
Equipment is provided for the transport, disassembly and chopping of the various fuel elements. Flexible facilities are provided for variations in fuel element construction or other special conditions in the fuel bundles. The major equipment pieces are
(a) Remote handling equipment, including two fuel handling bridge cranes, a power manipulator and four pairs of master-slave manipulators, one pair of which has extended reach. All operations in this area are carried out remotely by the use of this equipment.
(0) Radial saw table on which the ends of the element are sawed off after the element is positioned in a fuel carrier and on which special cutting can be done if the fuel cannot be pushed out of its casing.
(0) Pushout table, including a pushout ram and a drier for removal of fuel from basket and drying of fuel. There is a gas loop in the drier which is sampled to assure that the fuel is dried. The pushing pressure is controlled by a preset regulator.
(a) Fuel bundle carriers designed to hold a single fuel bundle by means of manipulator-operated clamps.
(e) Inspection table with a remotely operated vise, vee-blocks, gages, and other devices to hold and measure fuel elements.
(f) Fuel bundle shear for chopping the fuel into preselected lengths from 1 to 2 inches. The shear blade is driven by a hydraulic ram which can develop a 250-ton force. The hydraulic power units for this cutting operation are located in the aisle adjacent to the processing cell.
(9) Fuel-pin shear, a portable machine shearing single fuel pins if necessary.
(h) Maintenance table for the service and adjustment of incell equipment. It is designed for flexibility in handling the equipment and includes pneumatic portable harness, nibblers, and other power tools for the manipulator equipment.
(i) Transfer cart used in the airlock between the mechanical and chemical cells designed to prevent accidental dropping of the fuel basket and remotely removable for maintenance.
(i) Remotely operated shielding door for foyer into which the manipula
tor and cranes can be removed for decontamination and maintenance, Dissolvers
There are two batch dissolvers made of 309 SCb stainless steel with a nominal capacity of 2,000 gallons designed to dissolve 1,000 kilograms per day uranium as UO2. They are located in the CPC partially isolated from one another and are designed for remote maintenance and replacement. A third dissolver will be provided later. This will either be made of titanium to accommodate Darex dissolutions or will be of stainless steel and set up to permit electrolytic dissolution of stainless steel-cermets.
The dissolvers are cylindrical tanks containing a heating coil in the bottom and a condenser coil located in a bustle around the top. Each dissolver has four 15-inch-diameter openings equally spaced on the top. Each of these openings is fitted with a weighted cap which may be removed to receive fuel baskets and which provides the seal for the opening during dissolution. Underneath each of these openings there are guides which will accept &inch-diameter fuel baskets. Chopped fuel in baskets is introduced into the dissolver by means of
Acid is added to the dissolver from the solution makeup area. Offgases from the dissolution pass over the condenser coil and condensate is directly returned to the dissolver vessel to maintain the liquid level and solution strength.
Each dissolver has a series of appartenant equipment for handling the off-gas from it, including an off-gas scrubber, a condenser, and a silver reactor. During dissolution, the liquid level and density of the solution is continuously recorded and the system pressure is recorded and controlled by a PRO in the off-gas line, backed up by a manually controlled valve. Alarms are provided for high- and low-liquid level, temperature of solution and off-gas, and off-gas pressure. Pulse columns
Continuous solvent extraction is effected by 10 pulse columns listed in table 5 (see also figure 5.34 in the safety analysis). The columns are fabricated from 304-L stainless steel and located in three extraction cells. They perform the functions of extraction, partition, stripping, and scrubbing. All will have cartridges of boron-304-L stainless plates installed in the enlarged disengaging sec tions to protect against criticality. Control of the columns is maintained primarily through control of the effluent from the bottoms of the columns and by control of aqueous effluent removal and interface level through sensing pots lo cated near the tops of the columns. Further, the column bottom pressure, temperature at the top and bottom of the column and specific gravity of the organic efiluent are recorded.