Conventional attack - civil nuclear

This risk is featured in the full matrix, representing the averages of multiple different scenarios presented together in the ‘conventional attack on infrastructure’ category.

Impact 5
risk indicator
ID 10
Risk theme Terrorism
Impact & Likelihood
Impact key
5 Catastrophic
4 Significant
3 Moderate
2 Limited
1 Minor
Likelihood key
5 >25%
4 5-25%
3 1-5%
2 0.2-1%
1 <0.2%


Civil nuclear power is of strategic importance to the UK’s energy resilience and clean energy transition, and a safe mode of generating electricity. Within the UK, and in line with international good practice, an independent regulator holds operators to account. The Office for Nuclear Regulation requires nuclear power sites to demonstrate their ability to defeat very advanced attacks that could lead to the loss of nuclear material or the release of radiation.


In line with international good practice, the UK’s domestic legislation requires planning for a range of scenarios, including those far beyond a reasonable worst-case. This scenario is extremely unlikely. It is based on a physical attack at a UK civil nuclear installation resulting in radiological contamination off site. The scenario mirrors that of a civil nuclear accident but has the additional component of an active counter-terrorist policing operation.

Key assumptions

Scientific modelling has been used to determine the scenario and the countermeasures required.


Smaller-scale scenarios could occur with a lower percentage of inventory being released. This would decrease the level of impact on people, the environment and the economy. The attack could happen on a range of sites.

Response capability requirements

In addition to the response capabilities set out in the civil nuclear accident scenario there would be a large-scale, multi-agency response including counter-terrorist policing. A detailed communications campaign would be needed to communicate key messages to the public. Protective actions would be promptly implemented to protect people’s health and safety.


Around affected parts of the UK there would be significant prolonged long-term security, health, environmental and economic impacts requiring sustained recovery.