Significance of analog instrumentation [nuclear plants]

The differences of opinion concerning power plant instrumentation, including safety systems, are discussed. One popular viewpoint is that modern instrumentation must be microprocessor-based to be acceptable. An alternative viewpoint is that properly designed analog instrumentation is recommended in some applications and has proven to be viable based upon performance and experience. It is pointed out that, for most applications, analog instrumentation is simpler and more reliable, and can be more cost effective. For replacement instrumentation and for upgrade instrumentation, analog instrumentation provides a lower overall cost approach. The system changes with analog instrumentation allow a simple technical justification, and the qualification required for analog systems is easier and less expensive