Power FluidicsTM is the generic name for a range of maintenance-free nuclear equipment built around the common principle of using one medium, most commonly air, to move fluids. In nuclear applications, these fluids are mainly radioactive liquids or sludges. Power fluidic pumps, mixers and samplers have been used in nuclear installations for the past 20 years and more than 400 systems have been installed to date with no failures. The devices have no moving parts in contact with the contaminated medium and therefore require no maintenance of contaminated equipment.
Significant savings are achieved through using Power Fluidic devices in place of their mechanical equivalents by:
- Eliminating replacement costs of worn out components.
- Reducing secondary waste due to worn out components and maintenance work.
- Reducing health physics and safety paperwork associated with the maintenance.
- Increasing plant productivity due to reduced maintenance schedules.
PRINCIPLES OF POWER FLUIDIC TECHNOLOGY
A fluidic system typically consists of the following modules, or skids:
- Charge Vessel Skid
- Control Skid
- Off-Gas Skid
Typically, each of these modules is located above ground adjacent to the tank, connected by the requisite electrical and instrument cables, and flexible hoses for air, water, and slurry/sludge. The system is controlled using NuVision Engineering's patented PRESCON® controller which is housed in a mobile weatherproof 'hut.' Ventilated air from the system is discharged through a mobile HEPA filtered off-gas skid.
A typical system mobilizes and retrieves waste via a three phase mixing process:
- a suction phase;
- a drive phase; and
- a vent phase.
The system mobilizes the sludge contained within the designated supply tank by first sucking liquid out of the tank into the charge vessel, entraining a small amount of sludge. This liquid is then repeatedly forced backwards and forwards between the tank and the charge vessel thereby gradually entraining more sludge into the liquid. During this operation, gas is vented out of the jet pumps to an off-gas system.
The mixing process is repeated until the sludge/liquid mixture around the tank nozzle breaks through into the overlaying supernate layer. Once this occurs, the mixing cycle continues until the required suspended solids composition is reached, at which point the mobilized sludge/liquid is pumped out of the tank. Tank waste retrieval is achieved by filling the charge vessel from the tank and then discharging the charge vessel via a valve manifold to a delivery line instead of back to the tank.
The system configuration may be further modified by addition of a remotely operated directable nozzle which is incorporated into the system above or below the charge vessel. The contents of the charge vessel can be discharged through this nozzle via a valve manifold. The jet of liquid discharged through the nozzle can be used to assist in mobilizing sludge, or for tank wall washing.
Power Fluidic devices have been used for mixing, sampling and retrieval operations at a number of US DOE sites including Oak Ridge, Los Alamos, Idaho Falls, Savannah River and Mound. The systems have performed flawlessly and have proven to be an extremely cost-effective alternative to conventional tank mixing and retrieval equipment. |
