Recent Insights from the International Common-Cause Failure Data Exchange (ICDE) Project

Abstract of the technical paper/presentation presented at:
Proceedings of the 30th European Safety and Reliability Conference and the 15th Probabilistic Safety Assessment and Management Conference
June 21–26, 2020

Prepared by: Hayat Chatri1, Yolande Akl1, Gunnar Johanson2, Jeffery Wood3 and Benjamin Brück4
1Canadian Nuclear Safety Commission, Canada
2ÅF Industry, Sweden
3United States Nuclear Regulatory Commission, United States of America
4Reaktorsicherheit (GRS) gGmbH, Germany


Common-cause failure (CCF) events can significantly impact the availability of safety systems of nuclear power plants. For this reason, in 1994, a number of countries initiated the International Common-Cause Failure Data Exchange (ICDE) project. Since 1997, the Organisation for Economic Co operation and Development’s Nuclear Energy Agency (OECD NEA) has successfully operated the project over seven consecutive terms (the current term being 2019–2022). The ICDE project allows multiple countries to collaborate and exchange CCF data to enhance the quality of risk analyses, which include CCF modelling. Because CCF events are typically rare, most countries do not experience enough of them to perform meaningful analyses. Input combined from several countries, however, has yielded sufficient data for more rigorous analyses.

The ICDE project has published 11 reports on the collection and analysis of CCF events of specific component types (centrifugal pumps, emergency diesel generators, motor-operated valves, safety and relief valves, check valves, circuit breakers, level measurement, control-rod drive assemblies, heat exchangers), as well as five topical reports, with another three reports in the preparation stage.

The ICDE project has greatly changed the view of CCFs. Many insights, such as the determination that complete CCFs seem to be most often the result of human action as a part of operation or design rather than manufacturing deficiencies, would not have been possible without deep plant data collection and combining information from many sources.

This paper presents recent activities and lessons learned from the data collection and the results of topical analyses on intersystem dependencies and pre-initiator human failure events.


  1. ICDE Project Report: Summary of Phase VII of the International Common-Cause Data Exchange Project, NEA/CSNI/R (2019)3, June 2019.
  2. ICDE Topical Report: Collection and Analysis of Common-Cause Failures due to Plant Modifications, NEA/CSNI/R (2019)4, 2019.
  3. ICDE Topical Report: Provision against Common-Cause Failures by Improving Testing, NEA/CSNI/R (2019)5, 2019.
  4. ICDE Topical Report: Collection and Analysis of Multi-Unit Common-Cause Failure Events, NEA/CSNI/R (2019)6, 2019.
  5. Draft ICDE Topical Report: Collection and Analysis of Intersystem Common-Cause Failure Events.
  6. Draft ICDE Topical Report: Collection and Analysis of Common-Cause Pre Initiator Human Failure Events.

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