Balance-of-plant heat exchanger condition assessment guidelines

In nuclear power plants, service water system heat exchanger integrity and thermal performance are receiving close scrutiny to ensure that they perform their functions in an emergency condition. Many safety-related service water systems are called upon to function only in emergency conditions and are therefore difficult to monitor on a regular basis to ensure functionality. For some heat exchangers it is difficult to measure and extrapolate their thermal performance data since performance testing is often conducted at flows, temperatures, and heat loads which are different from design conditions. Tube fouling and plugged tubes may also contribute to this difficulty. Performance testing and analysis of heat exchanger alone does not provide information relative to structural integrity of remaining tubes. This document is provided to complement the existing performance testing with a periodic inservice inspection program