I. PURPOSE AND SCOPE

This project establishes a systematic method for specifying, documenting, reviewing, and controlling instrument setpoints. This effort will enhance the effectiveness of the plant's overall configuration management program by assuring design control of instrument setpoints and the associated test and calibration procedures, including better control and management of setpoint changes.

Current instrument maintenance practice is to use the instrument manufacturer's rated accuracy as the basis for the required accuracy for most individual instrument calibrations. The instrument data sheets provided in FP-50174 list instrument rated accuracy and the required accuracy, which is simply supposed to be less stringent than the rated accuracy of a given instrument. The basic design approach is to determine the needed accuracy for instruments, then purchase and install equipment capable of meeting the requirement. Then the plant personnel keep track of actual calibration data. Since the information in the instrument data sheets has not been kept up to date, it cannot be used as the basis for managing and, where needed, changing the accuracies contained in instrument calibration procedures. Additionally, adjustments to the calibration frequency are dependent on such records (set and drift).

Completion of this upgraded setpoint program would yield both labor and dose saving benefits that would provide immediate payback when applied to instrumentation loops in high dose areas. Instrument loops that are being calibrated too frequently due to the arbitrary use of an instrument's available set point drift data would also realize these labor and dose savings. Also, improvements in setpoint control would have a positive impact on several routine instrumentation tests.

II. EVALUATION

Schedule Index: 11 - The project could potentially reduce the chance of failing to actuate important systems automatically during accident scenarios due to common cause miscalibration errors. However, since the Emergency Operating Procedures (EOPs) direct operators to start equipment manually when automatic has failed, the impact of this failure is not as important from a PRA standpoint . A nuclear safety factor of 0.2 is assigned to this initiative since it has a low impact on safety systems of high importance (0.2 x 32). Unit availability is moderately increased with a potential reduction in plant trips (0.2 x 12). ALARA is somewhat enhanced with a 6 person-rem reduction for this project (0.2 x 9).

Economic Aspects: After initial project work is complete, there will be some continuing effort to maintain plant setpoint control. The estimated ALARA savings is $60,000/year (6 person-rem x $10,000) plus the potential savings resulting from increased availability.

Related Standards: The work Management Policies for operating parameters and design documentation standards are applicable to this project.

Other Considerations: This project is not outage dependent.

The project will accomplish both dose and labor savings for the BSEP. Increased control of safety margins will result from better management and use of instrument set point calibration data. The improvements in setpoint control will enhance nuclear safety and in some cases, it may also reduce unit trips, but the principal objective of the project is to achieve reductions in exposure by reducing unnecessary calibration tests and instrument adjustments (6 person-rem/yr).