Committee on the Safety of Nuclear Installations (CSNI) International workshop on

Robustness of Electrical Systems of NPPs in Light of the Fukushima Daiichi Accident

Paris, France, 1-4 April 2014



Introduction

BACKGROUND

The Defence in Depth of Electrical Systems (DIDELSYS) Project (2008–2011) was launched after a switchyard-induced voltage surge event at Forsmark NPP in July 2006 caused the loss of two of four safety-related AC buses along with all connected I&C and support systems. The DIDELSYS Project was focused on providing recommendations to address internal plant and grid upset events and the ability to safely recover. The March 2011 Tsunami-induced Station AC Blackout accident at Fukushima Daiichi identified loss of AC power concerns that were associated with severe external events, that were beyond the scope of the DIDELSYS Project. The Committee for the Safety of Nuclear Installations (CSNI) chartered a Senior Task Group on Robustness of Electrical Systems of NPPs in Light of the Fukushima Dai-Ichi Accident to evaluate the safety implications of severe external events on safety related electrical systems. The Senior Task Group on Robustness of Electrical Systems of NPPs (ROBELSYS) is responsible for the committee's programme of work in the area of improving the robustness of safety-related electrical systems in nuclear power plants.

The main purpose of ROBELSYS Project and its products are to improve the understanding of nuclear power plant electrical system robustness and defence in depth by comparing design practices and plant emergency and operating procedures in member countries; improve the safety review process of nuclear power plant electrical systems by learning from best practices in member countries; and promote cooperation among member countries to improve safety.

OBJECTIVES OF THE WORKSHOP

The objective of this international workshop was to provide a forum to exchange information on simulation and design of safety related electrical systems in nuclear power plants around the world. Key focus areas included:

SCOPE, CONTENT AND OUTLINE OF THE WORKSHOP

The workshop included technical sessions devoted to technical presentations by participants on the topics outlined in the preliminary workshop programme above and a final session. The final session summarized the discussions and developed conclusions and recommendations for possible further actions by the CSNI. All of the participants were expected to take part in the discussion and in the formulation of conclusions in the final session. Papers and case studies addressing the issues and topics outlined were welcomed. Several sessions with ample time for discussion were defined according to these topics.

Last reviewed: 6 April 2014