IEC 61505:1998

FOREWORD
INTRODUCTION
1 Scope and object
2 Normative references
3 Terms and definitions
4 Abbreviations
5 Physics, measurement and analyses of instabilities
      5.1 Physics of BWR core instabilities
      5.2 Possible consequences of core instabilities
      5.3 Measuring principles
      5.4 Analysis methods
6 Functional requirements
      6.1 On-line monitoring
      6.2 Off-line monitoring
      6.3 Man-machine interface
      6.4 Response time
      6.5 Accuracy
      6.6 Robustness
7 Safety classification
8 Technical requirements
      8.1 Data acquisition system
      8.2 Data processing and operator interface system
      8.3 Hardware (HW)
      8.4 Software (SW)
9 Verification and validation
10 Testing and maintenance
11 Qualification and documentation
Figure 1 - The four methods of coolant recirculation through
           the core of a BWR
Figure 2 - Neutronic and thermal-hydraulic feedback
           mechanisms
Figure 3 - Feedback mechanisms for coupled neutronic-
           thermalhydraulic reactivity instability
Figure 4 - Example of BWR stability monitor
Annex A - Automatic detection and suppression
Annex B - Examples of BWR power oscillation occurrences
Annex C - Examples of instability tests
Annex D - Instability prevention concept
Annex E - Operating experience with stability monitoring
Annex F - Estimation of neutron noise characteristic function
Annex G - Estimation of phase difference
Annex H - Bibliography

Describes appropriate plant parameters for use in stability monitoring; defines analysis methods for relating time-varying plant information to reactor stability figures of merit (such as the decay ratio); and provides technical guidelines regarding stability monitoring requirements.