Human factor issues affect most aspects of plant design, operation and maintenance. The subject has received increasing attention over recent years from both regulators and utilities. Operating experience has shown that plant personnel and the systems within which they operate, play a very important contribution to safety.

There have been recent efforts in human factors engineering, ergonomics, and biomechanics to improve understanding and safety operation (Ramsey, 1998). These have also included human/machine interfaces and the development of special purpose systems. These must manage various data inputs relating to information gathering and output to maximise human and machine performance. Techniques for human error rate prediction (THERP) have been established. These compile human error rates for various industrial tasks. Comparisons with other industries indicate that nuclear facilities generally meet very high comparative degrees of safety. Studies of human attitudes and physical limitations are given in USNRC (1992). An account of workers responses to events and their compliance with control measures is given in SOER92-1 (1992).

Human factors’ issues have been recognised by the UK regulator via specific safety assessment principles addressing human factors issues (Dixon, 1998).

One method of improving safety is to identify factors that impact on performance of a particular job. Utilities have developed a number of techniques to help them to analyse particular tasks. Factors that impact on performance include design of interfaces, the procedures in place and staffing levels and training. Good practice guidelines that have been recommended include the adoption of user friendly operating instructions and peer review of proposed changes, etc.

The HSE in the UK has also recognised the importance of broad-ranging organisational factors including safety management systems and safety culture (Dixon, 1998) (Table 3.5). The establishment of good safety culture within organisations is important to ensure the implementation of safety principles at all levels within the plant. The HSE, in common with most other safety authorities, believes that the licensee should own its safety cases. This is particularly important today in many countries including the UK, where nuclear industries are undergoing rapid change and where there is increasing use of contractors.

BNFL/Magnox Generation commissioned a study to establish the relationships, if any, between employee safety awareness and safety performance (Spooner and Vassie, 1999). This study identified five factors — training/experience, safety initiatives, communication, organisation and personnel.

The participants in the study felt that safety awareness was developed partly via common sense and partly via specific skill training. Personal experience, particularly of an unsafe event, was not surprisingly, highly influential on an individual’s safety awareness, but in addition learning from a colleague’s experience was also influential. Training/ experience were considered to be key influences in employee safety awareness.

Safety initiatives such as ‘near miss’ reporting were regarded as effective in promoting safety awareness. It found that performance-related bonus schemes, including the achiev­ement of specific safety targets did not significantly influence safety-related behaviour. This would appear to contrast the situation in certain organisations in North America.

The study appeared to show that passive forms of communication, e. g. notices, had less impact than verbal communication; e. g. team briefings were found to be more effective. The employment of active communications’ systems, e. g. PA and VDU systems, was also considered to be more effective.

It was concluded that improved communication of learning events was useful and that the organisation should be in place to do this. How the organisation responded in resolving

Table 3.5. Human factors issues

Impinge on plant design, operation and maintenance Task analysis — procedures, training, interface design, staffing levels Safety culture at all levels — organisation, plant management, staff Licensee ownership of safety case — cf. use of contractors

safety issues was also considered but the participants did not feel that this contributed significantly to safety awareness. However, further work was required.

Personal relationships, including interactions within a group and responsibility for others were considered to influence safety awareness significantly.

Although the study cited was specifically for the BNFL/Magnox Generating Group, it was felt that the conclusions have a wider application to other similar organisations.

Safety management and safety culture have been reviewed in a recent IAEA international conference on safety culture in nuclear installations held in Rio de Janeiro in December 2002 (IAEA International Conference, 2002; IAEA/NSR/2002, 2003). This conference confirmed that safety culture is now regarded internationally as an important element of nuclear safety. The IAEA Nuclear Safety Standards Committee endorsed a proposal in 2002 to develop safety standards specifically addressing safety management and culture. Two particular issues identified at this conference were that although safety culture is now embraced by top management, there is still a need to broaden appreciation through to the shop floor. It was also noted that safety culture is being embraced more enthusiastically in countries with a developing industry, than in those which had long — established nuclear programmes.