IEC 62117:1999

FOREWORD
INTRODUCTION
1 Scope and object
2 Normative references
3 Definitions and abbreviations
4 Operational conditions
      4.1 General
      4.2 Cold shutdown maintenance operations
      4.3 Cold shutdown refuelling operation
5 Measurement methods
      5.1 General
      5.2 RPV water level measuring devices
             5.2.1 Differential pressure measurement
             5.2.2 Heated sensor measurement
      5.3 RPV outlet pipe water level measuring devices
             5.3.1 Differential pressure measurement
             5.3.2 Ultrasonic liquid level monitoring
      5.4 Core exit temperature sensing devices
             5.4.1 Core exit thermocouples
             5.4.2 RPV outlet pipe temperature
             5.4.3 RHRS temperature
6 Instrumentation requirements
      6.1 General requirements
             6.1.1 Safety classification
             6.1.2 Accuracy and response time
             6.1.3 Reliability
             6.1.4 Single failure considerations
      6.2 Differential pressure measurement
             6.2.1 Differential pressure transmitters
             6.2.2 Reference columns
             6.2.3 Differential pressure tap locations
             6.2.4 Hydraulic instrument line installations
             6.2.5 Hydraulic instrument line temperature
             6.2.6 Type and quality of the fluid in the
                      instrument lines
      6.3 Heated sensor measurement
      6.4 Ultrasonic liquid level measurement
             6.4.1 Application
             6.4.2 Accuracy and time response
             6.4.3 Installation considerations
             6.4.4 Special human machine considerations
      6.5 Temperature sensing devices
7 Data processing
8 Presentation of information
9 Verification and calibration
10 In-service testing and maintenance
11 Qualification
12 Documentation
Annex A (informative) Loss of core cooling events during
                      cold shutdown at PWRs
Annex B (informative) Plant operating states

Gives requirements for instrumentation to monitor core cooling for safe operation of PWRs during cold shutdown operations when the coolant temperature is below 100 °C. Summarizes good international practices to be used when designing new or upgrading existing PWR core cooling monitors.