Nuclear power plants - Instrumentation systems - Measurements for monitoring adequate cooling within the core of pressurized light water reactors

IEC 60911:2025 applies to pressurized water reactors (PWRs) and presents requirements for the monitoring of adequate cooling within the core in all operations, including normal and abnormal operations. Requirements for core cooling monitoring during conditions beyond a design basis accident, i.e. a design extension condition of type A or type B, are also covered in this document.

This document defines requirements for instrumentation to measure coolant parameters, which are of interest when abnormal conditions arise with either one or two phases of coolant or with gas included in the reactor pressure vessel (RPV).

This second edition cancels and replaces the first edition published in 1987. This edition includes the following significant technical changes with respect to the previous edition:

a) Modification of the title.

b) Integration and merging with the content of IEC 62117:1999 relative to the monitoring of core cooling during cold shutdown.

c) Integration of feedback following the 2011 Fukushima accident.