IEC 62118:2000

FOREWORD
INTRODUCTION
1 Scope and object
2 Normative references
3 Definitions and abbreviations
4 Operating conditions
      4.1 General
      4.2 Normal power operation
      4.3 Hot shutdown operations
      4.4 Abnormal and accident conditions
      4.5 Cold shutdown operations
5 Measurement methods
      5.1 General
      5.2 RPV water level measuring devices
      5.3 RPV inlet/outlet pipe water level measuring
             devices (systems as shown in figure 2)
      5.4 Core exit temperature sensing devices
6 Instrumentation requirements
      6.1 General
      6.2 Differential pressure measurement
      6.3 Heated sensor measurement
      6.4 Ultrasonic liquid level measurement
      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) Events with potential core cooling
                      degradation at VVERs
Annex B (informative) Plant operating states
Figure 1 - PWR configuration: (VVER-440) - Horizontal
           steam generators
Figure 2 - PWR configuration: (VVER-1000) - Horizontal
           steam generators
Figure 3 - Water level measurement by differential pressure
           method for VVER 1000
Figure 4 - Thermal-hydraulic considerations affecting water
           level measurements (VVER-1000 systems) at reduced
           inventory and reverse flow
Figure 5 - Water level measurement by direct acting
           transmitter (VVER-1000 systems) at reduced
           inventory and reverse flow

Applies to pressurized water reactors (PWRs) of VVER design and presents the requirements for monitoring adequate cooling within the core during hot and cold shutdown conditions. Requirements are given for core cooling monitoring instrumentation to ensure the safe operation of VVERs during abnormal operation and during and after design basis accidents (DBA).