Service Water and Closed Cooling Water Systems
in Nuclear Power Plants

Most service water systems in nuclear power plants fall into the category of “raw water” systems. They include safety-related and non-safety-related systems (essential and non-essential).

Failures in safety-related service water systems can challenge the safe shutdown of a plant.

The Nuclear Regulatory Commission (NRC) pays close attention to the integrity of safety-related service water systems via Generic Letter 89-13.
Failures in a non-safety-related service water system may not challenge a safe shutdown, but they can prevent the plant from generating electricity. Failures in components such as turbine lubricating oil coolers, hydrogen coolers, etc., can prevent the plant from operating.