New air crash requirements proposed

Wednesday, 25 April 2007 American regulators may require assessment of new reactor designs to include assessments of how they could afford greater protection against deliberate aircraft crash.

The US Nuclear Regulatory Commission (NRC) has proposed the change in security requirements of future nuclear power stations and will seek comment from the public, the nuclear industry and the technical community from later this year.

If accepted, a new rule would affect reactor vendors submitting their designs to the NRC for design certification, as well as companies applying to build a reactor that had not yet received design certification. They would have to assess how the reactor design, "to the extent practicable" could have greater built-in protection to "avoid or mitigate the effects of a large commercial aircraft impact, making them even more resistant to an attack."

The aim of any design modifications, which would be made at an early stage in the licensing process, would be to reduce the reliance on action by the plant operators in such an event. The focus of safety improvements would be reactor core cooling capacity, and the integrity of the reactor containment and the used fuel pool.

Nuclear power plants are already recognised as being among the most robust structures, which also boast the most comprehensive security of any industrial facility.

The new rule would be the third step taken by the NRC in response to the events of 11 September 2001. In January, the NRC updated its Design Basis Threat (DBT) rule on radiological sabotage to cover attacks on nuclear plants from land, water and the internet. The NRC excluded from the DBT any requirement for nuclear plant operators to defend against the threat of deliberate air crash, ruling that the necessary weapons for such defence out of the scope of the companies, and that the responsibility for air security lay with government agencies such as the military.

In February 2002 the NRC required nuclear plant operators to "develop strategies to mitigate the impact of large fires and explosions that could be caused by an aircraft impact."

The NRC has always required reactor designs to be brought to a safe shutdown and withstand stresses beyond those caused by Design Basis Events such as: large pipe breaks; fires; earthquakes; hurricanes; tornados and floods.