01 September 2003
PCs control nuclear waste
By Ellen Fussell
In Richland, Wash., home to the Hanford Nuclear Reservation, businesses like Advanced Control and Engineering are doing their part to prevent nuclear waste from leaking into the river. If the waste corrodes, some of the waste could dissolve in the water table and make its way to the river—or worse, the drinking water. (A water table is a pocket where water collects—where it seeps into the ground.)
At Advanced Control and Engi-neering, Erwin Icayan and his team implemented a control system with the basic interface to manufacturing execution systems (MES) for the Department of Energy. The system allows users to move nuclear waste from single shelf tanks to the more secure double shelf tanks, making information available to the rest of the company's information systems. "This means we gather the data for each of the control elements or control parameters. And we store it and provide an interface so people in the company—not necessarily engineers or control folks—can have access to do data mining or analysis so they can evaluate efficiencies," Icayan said.
The system will work well for a manager or for someone working out a process. "Some scientists are curious about the data patterns coming out, say, custody transfer," he said. The data is for mass balance of nuclear waste. Mass balance tells you how much you are transferring in mass instead of just a liquid-type flow, which is usually not homogenous material. "If it's something like water, it's easy to use flow to calculate how much water is transferred. If you have suspended material, the flow doesn't tell you how much is suspended because it isn't homogenous," Icayan said. The amount of suspended material is not constant. So you have to determine how much mass is being flowed out instead of just liquid flow.
In this particular case of gathering data, the client has to monitor all these process elements, the density or mass flow, to evaluate how much waste has been transferred.
Icayan's team used a programmable logic controller to implement the control system. "We put a database [intermediary database] to gather data for information systems or data mining or other kinds of data analysis," he said. With the system, users could view data over the Internet. Although this scenario is "kind of different" according to Icayan, "it's being implemented more and more these days. The thing that's preventing it from really taking off is security. If you're controlling a power plant or a substation over the Internet, you don't want anybody to be able to hack into it and disrupt your control and make it do things dangerous or disruptive," he said. So there's a question on how to implement that type of security when you're using it for control over the Internet.
Icayan's latest project spanned 500 square miles. His team interfaced a control system to the Department of Energy's intranet to use for data mining and analysis information. "Let's say the control system is out about 5–10 miles away from where the process engineer is sitting, the one who's concerned about the mass balance for transferring the nuclear waste from one place to the other," Icayan said. "He can go over the Internet and grab a group of data to find out how that transfer is progressing. So he can easily find out how much waste has been moved through a mass-balanced algorithm. In the place he's transferring it to, he can start updating the inventory of that waste." Because it is nuclear waste, they are mandated to keep track of the amount of nuclear material present.
Icayan's system controls the pumping—the movement to the double shelf tank. "There's a system that dissolves the waste, or mixes it up to get it ready. We run the pump that pumps waste up from the tank onto this pipeline, and the pipeline deposits the waste into another tank," Icayan said. The control system is out in the field. The process engineer is at a remote location instead of at that control system. "That's what's neat about the Internet. The engineer can bring up Internet Explorer and go find the data—and then do his analysis for mass balance," he said. "The data he'll be looking at is pretty much real time." IT
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