A control system for the cross-site transfer system for
radioactive waste liquids and slurries at the Hanford Nuclear Reservation
was provided by Programmable Control Services, Inc. of Spokane. The system
is cost-effective, meets safety standards and can be expanded in the
future.
As part of the clean-up of the Hanford site in Richland, Washington,
liquid and slurry wastes from the 200 West area are being transferred to
the 200 East area for centralized processing. The existing transfer line
did not meet present safety standards, so a new system with required
primary and secondary containment was installed. The new double-wall pipe
with leak detection between the walls is seven miles long.
The cross-site transfer system SCADA (supervisory control and data
acquisition or master controller) provides control and monitoring for the
transfer of liquids. Controls are distributed between two Pentium PC
operator interface terminals (OITs) and five Allen-Bradley PLC-5
programmable logic controllers (PLCs). The system communicates over a
fiber-optic Allen-Bradley Data Highway Plus (DH+).
The OITs are running Rockwell Software's RSView and provide windows
into the process, showing transfer status, valve positions, pump status
and alarm indication. The operator entries include acknowledging alarms,
selecting the transfer mode, requesting valve position changes and
starting or stopping pumps. Control actions by the operator require
"select before actuate" entries.
The control resides exclusively in the five PLCs, referred to as
process control units (PCUs), which are at five separate locations. Each
of the PCUs also provides a termination location for the input devices
located in its area.
This design provides coordinated system control over the network, while
each PLC provides the local control for its area. Capabilities at each
location were tailored to the requirements for cost effectiveness.
Additional I/O may be added for expanded functionality in the future.
