Common-cause failure (CCF) events can significantly impact the availability of safety systems of nuclear power plants. For this reason, the International Common-Cause Failure Data Exchange (ICDE) Project was initiated by several countries in 1994. In 1997, the Committee on the Safety of Nuclear Installations (CSNI) formally approved the carrying out of this project within the OECD Nuclear Energy Agency (NEA) framework.
This report documents a study performed on a set of 146 CCF events related to level measurement components from 1983 through 2003. The function of the component “level measurement” is to monitor the liquid level in safety relevant vessels, tanks and piping. The events studied here were collected in the ICDE database. Organisations from Canada, Finland, France, Germany, Sweden, United Kingdom and the United States contributed to the exchange. The ICDE project is a unique international effort where large amounts of data from different countries are collected and analysed to draw conclusions about common cause failures.