By Nancy Spring, Senior Editor
When Entergy Nuclear adopted the latest wireless technology at its River Bend Nuclear Station, the company successfully modernized one of its plants and maximized performance—and saved $4 million in the process.
“This project at River Bend is the replacement of a control system that we have for all of our outlying areas,” said Fred Wilson, senior project manager. “The traditional system would have been to install fiber optic cables.”
Transmission towers with all the necessary documentation and support they require would also have to be figured into the fiber optic cable project.
“It’s extremely costly to install fiber optics,” Wilson said. “The Innovations Group at Entergy was asked to help us come up with a solution and they came up with an excellent radio solution.” Because of the move to wireless, the cost of the project dropped from an initial projection of $7 million to $3 million.
River Bend is one of the first nuclear power plants to implement wireless technology for the continuity of a power project. Entergy Nuclear received an Honorable Mention award for the project from Power Engineering magazine for Best Projects of the Year 2009, nuclear power.
Entergy’s River Bend Nuclear station is located in St. Francisville, La., 30 miles north of Baton Rouge on the Mississippi River. With a maximum net power output of 998 MW, the single-unit facility began commercial operation in June 1986 and serves Entergy’s regulated business.
For the water intake process at the River Bend station, the Allen Bradley control equipment is located in three different buildings, the makeup water structure, the circulatory water system and the clarifier building. Traditionally, fiber optics and cable are used to tie all the systems together. Operations staff traveled several miles to the Mississippi to monitor and operate equipment at the makeup water structure. When the river was high, this entailed using a boat to reach installations, a safety hazard.
When the cable and fiber optics that carried information for nearly two miles needed to be replaced, Entergy’s Innovations Group and engineers from the River Bend station chose wireless technology instead. The wireless network ties the three locations to the auxiliary control room and the supervisory control and data acquisition (SCADA) system using wireless, radio frequency technology.
Work on the project took about nine months. Digging or trench work that would have been needed to replace the cable and conduit were unnecessary. Trees were cleared to insure consistency of wireless transmission and the timber was sold, with profits returned to the company.
“We’ve made about $28,000 so far on the sale of the timber so the radio system has just about paid for itself,” said Wilson.
Operations personnel are currently using the system to monitor pumps and other equipment at the makeup water structure. “At this point, all we’re doing with it is the actual controls to our outlying pumps, valves, switch gears and motors,” said Wilson. “In the near future we will add network capabilities.”
The system is actually capable of doing all of the plant’s remote vibration readings, too, which Wilson said will be added in the future, and plans call for extending the wireless network to the plant’s clarifier and the circulatory water system.
“I see what we are putting in now as the beginning of about a 5- or 6-year project to see how much we can do.”
Security and Reliability
The closed network that River Bend is using for indication and control is the Motorola canopy advantage wireless data network, said Mike Knop, special projects manager at Jackson Communications Inc., the company that provided the wireless equipment. The system operates at an unlicensed bandwidth and offers a 128-bit encryption algorithm.
“Entergy wanted that extra protection of having the data encrypted when it was sent out wirelessly,” said Knop. “It’s also password-protected.”
Ray Savich, Motorola product marketing manager, point-to-multipoint solutions, said the system provides multiple layers of security and is certified for safe transmittal of financial records, medical information and credit card information. The 128-bit Advanced Encryption Standard (AES) provides the highest grade security.
“It would take thousands and thousands of years to crack the 128 bit AES encryption code,” said Savich.
The project was designed with multiple, redundant secure networks to ensure high reliability. Two series of wireless equipment were installed, the Motorola canopy advantage 5400 series and the 5700 series, which operate at 5.4 GHz and 5.7 GHz respectively. With the dual system, if one series fails it is automatically switched to the other so there is no loss of data.
Interferance avoidance is built into the system. “We don’t expect problems like we’ve seen in the past with some river boat traffic interferences,” said Wilson.
From the central tower, the signal can easily travel three miles, said Savich. Point-to-multipoint systems have a range of up to 15 miles (and point-to-point solutions can cover 128 miles). The wireless system units are outdoors in self-contained and weatherproof housings, with cables that run indoors to connect to the SAIC equipment. Because the network operates in a spectrum below 10 GHz, it is resilient to moisture or precipitation. Snow and heavy rains have no affect on signal reliability.
Admittedly, wireless technology is not without concerns, such as cyber security and electromagnetic/radio frequency interference, said Richard Rusaw, EPRI senior project manager. But he said implementation experience and ongoing technical advances in cyber security funded by the Department of Energy demonstrate that these barriers are not limitations to implementation.
Work is currently underway at Entergy’s Grand Gulf Nuclear station to eliminate the need for traditional fiber optics and copper cabling required to establish network connectivity to radial wells on the Mississippi River. An instrumentation upgrade project there is slated for completion during the next two years. Installation of wireless equipment for general business network connectivity has begun at Entergy’s Vermont Yankee nuclear power station.
“As technology advances, there are many areas we haven’t looked at as far as communications and instrumentation and control,” said Marshall Rayburn, River Bend senior nuclear equipment operator. “We seem to try to fix the same equipment over and over when we could be using the new technology to do these same jobs cheaper and more efficiently.”
Over the years, optical fibers largely replaced copper wire communications in core networks and now fiber optics are being replaced by wireless technology. Motorola alone claims to have 2 million point-to-multipoint systems deployed around the world.
Wireless systems can provide the connectivity that network operators need, securely and cost-effectively. Point-to-multipoint solutions are widely deployed today for data transfer and SCADA, and the system can be installed in a fraction of the time that it takes to install a wireline solution, said Tim Mason, senior director of global solutions marketing for the wireless network solutions portfolio at Motorola.
Based on results so far, Entergy thinks additional efficiencies can be gained by leveraging and integrating this technology across the entire nuclear fleet.
For more features on wireless technologies, visit Power Engineering’s website at www.power-eng.com.
The Benefits of Wireless
The financial and technical benefits associated with using wireless technology in the nuclear power industry are difficult to ignore, said Richard Rusaw, EPRI senior project manager. “As facilities age, and as operators strive to reduce the total cost of plant operations, wireless technology offers one attractive improvement opportunity.”
Rusaw said installed estimates for cabling in a nuclear power plant can be as high as $2,000/foot, so wireless technology could also provide significant cost savings. Initial applications are primarily extensions of the business network, while new applications will target enhanced monitoring and equipment performance. Several utilities have installed wide area networks (WAN) in nuclear power facilities that provide significant productivity improvements.
“A lot of our customers that are looking for secure wireless solutions will typically turn to standards the federal government is defining as their minimum security standards,” said Tim Mason, Motorola’s senior director of global solutions marketing for the wireless network solutions portfolio. “We follow the highest levels of the government standards for security.”
The federal government is interested in wireless, especially as it pertains to energy efficiency. Wayne Manges, program manager for wireless systems at the Energy and Engineering Sciences Directorate, Oak Ridge National Laboratories, tracks wireless sensor technology for the Industrial Technologies Program, part of Energy Efficiency & Renewable Energy at the DOE.
“Wireless is considered a critical enabler for energy efficiency,” said Manges, whose work focuses on wireless sensors and controls for manufacturing and industrial applications.
Manges said Luminant’s Comanche Peak nuclear plant in Texas has had the world’s largest installation of wireless sensor networks for the past five or 10 years. “Wireless control is (already) being used, but River Bend is the first really broad application I’ve seen.”
The Motorola system’s modulation is proprietary, but the government is driving toward open standards. “We think that’s the future, not proprietary,” Manges said.
Is there any difference in the level of security between proprietary and open standards? According to Manges, developers of proprietary systems think no one knows how they did it, but they’re wrong, while with an open standards implementation, everyone knows how it was done “and you’re still secure. People in this business say that security through obscurity is neither.”