Brunswick's Honeywell 4010 process computers are the oldest installed and functioning reactor core monitoring computers in the United States. They were designed with technology that has become outdated and cannot be readily supported by the manufacturer. Also, technician training services and spare parts are no longer provided by Honeywell. Spare parts can be obtained at this time from third party sources; however, supplies are subject to depletion without notice. Although the many computer outages have not yet impacted the associated unit generation, their frequency has been rising, increasing the probability of startup delays or shutdowns.

The process computer's primary function, core monitoring, is currently dependent on and limited by the existing P1 software provided only by General Electric Corporation (GE). This software is less versatile and accurate than the variety of software now being written for DEC VAX (vice Honeywell) computers. In addition, limitations in fuel vendor selection are caused by the core monitoring software being GE-specific and less efficient than other available software. These fuel vendor limitations are considered to be a major disadvantage of the present system. In addition, as more complex fuel is used in the reactor core, it becomes increasingly difficult to predict the effects of core power adjustments, resulting in slower reactor startups and power adjustments than would be possible with a more capable system. The existing process computer system does not have sufficient capacity to accommodate the upgraded software needed.

The basic scope of the plant process computer replacement (PPCR) project is to transfer the functions currently being performed by the existing process computer to a system that has greater hardware/software capability, expansion capability, reliability, and maintainability. The existing process computer functions will be upgraded to perform more advanced computing and monitoring using the latest computer graphic capabilities. The new hardware includes front-end data acquisition equipment, data links, high speed DEC network interfaces to existing VAX computers, additional VAX systems, special purpose interfaces for the existing plant data system, and new operator consoles. Only the existing Honeywell input/output (I/O) cabinets will remain, serving as the interface between the plant sensors and the new data acquisition system. The new software includes the CPU's operating system licenses, data acquisition and data validation software, new core monitoring software, applications specific software, and system integration software that coordinates and monitors the entire system. Engineering services to support this project include providing documentation, testing, installation, training, conversion planning, and project management.

The testing and evaluation phase for the new system is extensive. After the new system's operation has been adequately verified, the existing Honeywell 4010 computer will be disconnected and removed using a phased approach. A long list of goals and success criteria have been established to confirm the adequacy of the new system. Abandonment and/or removal of the Honeywell process components will be a major milestone to indicate that important goals are being satisfied.

II. EVALUATION

Schedule Index: 13 - The process computer replacement is considered a non-safety related modification. Although it can be argued that the equipment is not safety related, the dependence of operators on the system output may have safety implications during operation. It is reasonable to predict that the graphic display benefits and predictive capability of the new system (especially as related to secondary plant process parameters) will reduce the frequency of secondary plant event sequence initiators (such as low condenser vacuum) relative to the frequency values considered in the PRA (0.2 x 32). The reliability, availability, and maintainability of the new system is expected to be much better than the previous system. As time goes on, the probability of unit downtime or startup delays increases with the old system (0.2 x 12). The computer replacement is viewed as a significant enhancement for the few personnel who need to use it, resulting in a plant enhancement (0.5 x 8).

Economic Aspects: The current 20 year old computer system can not last much longer without support from the vendor, so investment in a replacement is inevitable. The total cost for labor and equipment for process computer systems replacements and upgrades in both units, if performed according to the current schedule, will be about $10 million. The largest probable economic benefit is that the new system is much less likely to delay return to service after a refueling outage because of process computer system failures. It has been estimated that such a failure would result in a one to seven day increase in startup time. Also important is that the new core monitoring software, which will not run on the old computer, will permit CP&L to purchase fuel from more than one nuclear fuel supplier, enhancing competitive pricing. Finally, upon project completion, long-term system maintenance costs are expected to be reduced somewhat due to the increased availability of spare parts.

Related Standards: This project is related to Work Management Policies for material condition, operating parameters, and management oversight and corrective action. The PPCR project will improve the reliability, availability, and maintainability of the process computer systems, allowing better operational control. The project also supports the oversight standard to ensure that adverse conditions, excluding those that are self-revealing, shall be self-identified an average of 90% of the time.

Other Considerations: Other improvements in the ability of operators to monitor and tune the operation of the plant require the installation of the new process computer system before they become possible. It is anticipated that there will be measurable improvement in plant availability and net generation as a result of these other enhancements.

III. CONCLUSION

Almost all equipment has been purchased and is onsite. The modification package for Unit 1 has been approved and work is proceeding. Outage-related work is scheduled for outages B109R1 and B211R1.