WG C4.43 Lightning problems and lightning risk management for nuclear power plants

Background :

Lightning protection is an important concern for the design of power generation plants. Such concerns are particularly important in the case of nuclear power plants, where every effort must be made to minimize the risk of any accidents. Several factors should be considered concerning rational lightning protection for power generation plants.

Firstly, power generation plants should be protected from mechanical damage, fire and/or explosion due to direct lightning flashes to structures. Direct lightning flashes to structures can cause injury to human beings and appropriate protection measures are needed. Because over-voltages are generated by lightning flashes to structures, lines connected to the structures and the area nearby may be affected and, therefore, special care is necessary for the insulation design of the electrical systems. Furthermore, modern power generation plants use highly sophisticated control systems and sensors to operate the plants securely and effectively. This is done using numerous ICTs (Information and Communication Technologies); such systems are generally vulnerable to over-voltages induced by lightning and so must be protected from such over-voltages.

To establish a rational lightning protection design for power generation plants, in addition to the factors mentioned above, the cost for implementation must be taken into consideration. The concept of lightning risk management, therefore, must be introduced.

The IEC has already published international standards on lightning protection design for structures as IEC 62305 series and several MTs (Maintenance Teams) have been working to improve the standards. However, there is almost no international consensus on how to design lightning protection using the concept of lightning risk management for power generation plants, especially for nuclear power plants. From the considerations above, it is beneficial for society to investigate the latest knowledge on this problem and summarize it.

Scope :

1.Review the lightning protection design schemes for structures from the viewpoint of avoiding physical damage and over-voltages that could generate flashover at electric apparatus and lines and investigate the applicability of these schemes to nuclear power plants.

2.  Investigate lightning protection design practices of nuclear power plants available in the world.

3.  Propose a guideline on lightning protection design for nuclear power plants based on the concept of lightning risk management.

Convener: T. Shindo (Japan)

Progress Report 2016 (pptx, 97kB)