2017:34 Human capability to cope with unexpected events


In the light of the Fukushima accident, it stood clear that the challenge of the unexpected is of great importance to both regulators and licensees. For SSM, as for many other national regulators, there was a selfevident need to learn more about the capabilities and actions of people when the unexpected arises and conditions are potentially extreme.

A task group was set up within the OECD/NEA's Working Group for Human and Organizational Factors (WGHOF) in order to further the understanding of "Human Intervention and Performance in Extreme Conditions". The purpose of the SSM research project was to supplement the work within the WGHOF with areas that would not be covered as broadly. The project also had as an objective to supplement the IAEA's work on "Managing the Unexpected".


SSM defined the following objectives for the research project:

  • To gain a deeper understanding and provide a more complete illustration of:
    • how people function in extreme and complex situations
    • the support needed in these situations
    • how to prepare and train for unexpected situations
  • To learn from pre-existing research and, in particular, experiences from extreme accident and incident situations in the nuclear power industry as well as in other safety-critical industries (aviation, offshore, etc.)

The objective of the Authority was that the project would provide a basis for determining whether established safety policies, procedures/instructions and training in the nuclear power industry need to be developed further.

The expected content and scope were the following:

  • a survey of relevant existing research and, in particular, industry experiences
  • an analysis of a selection of relevant events from many safety-critical industries.

Important aspects to consider included problem solving and decision making, in particular in the following cases: a lack of information, limited resources in terms of staffing, time-critical phases, and stressful and extreme situations. Such situations may also include factors such as:

  • established procedures and instructions are difficult to follow or are not at all applicable
  • error messages or problem patterns do not match previously known conditions or mental models
  • the impact of uncertainty or the lack of understanding of the situation where it might be difficult for the persons involved to trust the reliability of presented indications.


SSM has established that the research provides a thorough overview of the challenges of unexpected events to people and organisations and the difficulty of identifying ways to take action and counter threats that arise.

The report explores the destabilising and threatening aspects of unexpected events and organisations established management of prevention of the unexpected by attempting to broaden the predetermined arena and solutions within organisations.

Furthermore, the authors describe a sample of available techniques for improving human capability to cope with unexpected events. One way forward is to develop resilience characteristics which are a compound of endurance and flexibility. This approach would apply to both the design of organisations and to socio-technical systems.

The report also covers the challenges this new approach to safety and managing unexpected events would present to regulators.