SAFETY PERFORMANCE

Much experience has been gained from around 50 years of successful and largely safe operation of nuclear power plant around the world. Undoubtedly the operational safety of most reactor systems has been improved by the collective knowledge acquired from all types of reactors. Many of the principles for safe operation relate to plant management and other generic factors and are not specific to a particular type of plant.

In the first instance, safety must be built into the plant design. This is usually referred to as engineered safety. Good design can prevent significant accidents through the intervention of good safety systems. Conversely there are examples where less good design has resulted in very significant major accidents. New designs will benefit from previous operating experience.

Operational safety has generally come to relate to the performance of plant personnel and the management of plant safety at the plant. The performance of management and staff can be judged against a number of performance indicators. Recent WANO data for collective radiation exposure and industrial accident rate are shown in Figures 3.1 and 3.2, respectively. These show steadily improving trends.

Although there may be differences in detail, performance indicators utilised by different utilities have much in common. For example, in the UK, BNFL/Magnox Generation, in a recently published review of station performance, consider indicators

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Figure 3.1. Collective radiation exposure for PWRs and GCRs (WANO). Source: WANO (2002).

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such as collective radiation dose, lost workday rates, the number and severity of events and the number of automatic trips (Marchese, 2000). Selective data are shown in Table 3.2 and these also indicate an improving trend.

There are a number of international standards which industry can use in assessing and improving performance. The internal safety system (ISRS) of Det Norske Veritas consists of different elements of performance. For example, element 1 relates to ‘leadership’ in putting emphasis on safety and reliability in achieving high standards of performance. The plant in question is then rated at a particular level. The system was used by BNFL/Magnox Generation in the review referred to above.

WANO performance objectives and criteria also include management performance. There is an increasing realisation that improvement in company business performance is commensurate with improvement of safety. A company needs safe reliable operation in order to be competitive. As inferred above then, both business and safety performance depend heavily on plant personnel.

The European for Quality Management (EFQM) model has been developed to provide a method for reviewing how management processes are actually working in practice. One of the features of EFQM is that both business and safety objectives and standards

Table 3.2. Safety improvements in Magnox plant

Measure

End 1980s

End 1990s

Collective dose (man Sv/reactor)

~ 0.5

~ 0.2

Lost work day case rate (per 105 h)

~ 0.9

~ 0.3

International nuclear event scale (INES) 1 (annual total)

~ 35

~ 14

INES 2 (annual total)

~2

0

should be implemented at all levels through the company. Regarding personnel development, the UK Investors in People (IIP) standard has been adopted by many companies in promoting the well being and development of their staff.

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