More and more plants are facing a dilemma: although their existing safety and non-safety instrumentation and control (I&C ) systems are functioning, the technology is old and is beginning to be difficult and costly to maintain. Representatives from two US plants, currently upgrading their I&C systems, outlined the analysis process that led them to the decision to upgrade their systems at the recently held Executive Forum for Emerging Challenges and Trends (EFECT) 2002 conference held in Palm Beach, Florida.

Analysis Process

The process that led both companies to their decision to upgrade their systems from analog to digital was similar. One of the primary drivers was the cost to maintain their current analog systems. Because much of the equipment is obsolete, replacement parts are often difficult to find, or the plant has to maintain large inventories as a safety valve if something needs repairing in a hurry. Due to the age of the system, the original vendor of the equipment may have only one or two people who are experts on the equipment or they may have gone out of business altogether. Over a 10-year period, Rafael Flores, Deputy to the Vice President, Nuclear Engineering and Support at TXU Energy estimated that their spare part costs would escalate by 200% if they continued to use the existing system. Maintenance costs with outdated equipment are higher and increase with each passing year and older equipment requires more frequent maintenance.

In addition, they found that they were facing recruitment issues. It is no secret that the current workforce at most plants is aging. It is all but impossible to attract young people to an industry using analog equipment when they have been trained on digital equipment.

Another aspect is the costs for performing surveillances. Because, in the older systems, it is performed manually, multiple people are involved such as schedulers, technicians, clerks, supervisors, and operators. By the time all the documentation is completed, procedures followed, and testing done, a large number of man-hours have been racked up. Although extreme care is taken to minimize errors, with that many people involved, the potential for errors exists.

Cost Reduction Potentials

Ron Affolter, Vice President, Nuclear at AmerenUE's Callaway Nuclear plant estimated that the Callaway plant could reduce its inventory costs by 50% by installing the digital system Ð and that is just for inventory costs. Flores agreed with Affolter and sees a reduction in personnel costs of about 30% over a ten-year period in addition to a probable 55% reduction in service costs.

Expected Benefits

• Improved plant reliability and operations for the life of the plant
• Increased safety through automation
• Distributive controls provide real-time diagnostics and real-time adjustments every second of the day - eliminates surveillance testing
• Single digital platform
  - Reduces number of systems experts
  - Perform licensing process only once
  - Ease of upgradeability
  - Interchangeability of parts
  - Reduction in operator mistakes
• Reduced maintenance and spare parts inventory
• Reduced manpower requirements
• Once trained to the new system, future training reduced

Part of the TELEPERM system upgrade at TXU

Both Callaway and TXU chose the TELEPERM^TM digital platform for their upgrades. Both are seeking the most effective and efficient system to run their plants safely for the life of their plants. By using an integrated approach and by sequencing the installation of the system, they are balancing disruption, costs and efficiency with safety.