Most of the arrangements for managing safety are in a very tangible form, which are easy to recognise and communicate. These consist of the site licence, policies, processes, procedures and organisational attributes, for example. To enact the work, staff will require knowledge and skills that can be objectively defined and instilled in the workforce.

Of even greater importance, however, is the need for personnel to go about their work with attitudes and behaviours which recognise the risks associated with the technology entrusted to them, that they act conserva­tively when making decisions that relate to safety, and that they strive to do their work to the best of their abilities at all times. Together these organi­sational attributes and the attitudes and behaviours are described as the safety culture of an organisation.

The term ‘safety culture’ was first introduced by the IAEA International Nuclear Safety Advisory Group (INSAG) in their Summary Report on the Post-Chernobyl Accident Review and subsequently published by them as IAEA Safety Series no. 75-INSAG-1. The term was later expanded and is now embodied in IAEA INSAG-4 published in 1991. The IAEA INSAG definition is:

‘Safety culture is that assembly of characteristics and attitudes in organizations and individuals which establishes that, as an overriding priority, nuclear plant safety issues receive the attention warranted by their significance.’

The World Association of Nuclear Operators (WANO) in their Peer Review programme and the IAEA in their OSART programme conduct reviews that seek to assess the status of safety culture in the plants that they visit. The IAEA also conducts specific missions to assess safety culture in NPPs known as SCART missions (Safety Culture Assessment Review Teams).

Following the Davis Besse vessel head incident, the US Institute of Nuclear Power Operators (INPO) developed a set of principles which should exist in organisations with a strong safety culture (INPO, 2004). These were published as a guidance document for the industry. The World Association of Nuclear Operators adopted the same principles in 2006.

There are difficulties in distinguishing between national culture and safety culture in international programmes but the WANO and OSART performance objectives and criteria overcome these difficulties.

In the INPO/WANO Principles for a Strong Nuclear Safety Culture, safety culture is defined as:

‘An organization’s values and behaviors — modeled by its leaders and internal­ized by its members — that serve to make nuclear safety the overriding priority’

This definition, together with the defining principles, are not incompatible with the definition produced by the IAEA but emphasise the role of leaders in defining the corporate culture of an organisation. The principles are:

1. Everyone is personally responsible for nuclear safety.

2. Leaders demonstrate commitment to safety.

3. Trust permeates the organisation.

4. Decision making reflects safety first.

5. Nuclear technology is recognised as special and unique.

6. A questioning attitude is cultivated.

7. Organisational learning is embraced.

8. Nuclear safety undergoes constant examination.

These principles are further characterised in detail in the documents. US utilities have established a safety culture assessment programme based on evaluation against the principles.