The operator of a nuclear plant is responsible for its safety. An important operating discipline is a robust performance improvement programme. The programme should have several elements in an overall interactive model. Elements of the model could include self-assessments, operating experience feedback, conduct of operations, performance assessments, oversight stan­dards, engineering programmes, and processes for dealing with any gaps that are identified. These elements would then fit into an overall perfor­mance model that has the following steps: (1) obtain the results for a per­formance monitoring/assessment element; (2) identify the gaps; (3) analyze and identify solutions; (4) implement the solutions; and (5) continue moni­toring. The objectives are to identify and correct problems, to identify and correct any negative trends before they become an issue, and to raise the sensitivity of management and staff to the importance of constant diligence and questioning attitudes. While a comprehensive discussion of all the ele­ments of a performance improvement model is beyond the scope of this chapter, two of the elements can be mentioned for illustration: self-assess­ment and operating experience feedback.

Self-assessment is a general process that can encompass both plant com­mercial performance and safety. Since performance and safety are bound together, self-assessments are a particularly important part of the overall safety structure. The IAEA Safety Requirements (IAEA, 2006d) for a nuclear facility management system mandate that: ‘Senior management and management at all other levels in the organization shall carry out self­assessment to evaluate the performance of work and the improvement of the safety culture’. Individuals and workgroups must assess their perform­ance against the licensee’s safety goals including the operating license requirements and other nuclear industry safety standards. One of the values of self-assessments is that they also recognize strengths and good practices that exceed the current requirements, and these might be used to enhance performance in other areas.

A policy should be developed that lays out the objectives and procedures for performing the self-assessments. Such a policy could include the scope for the assessments, the frequency, the process roadmap, the reporting and review mechanisms, quality assurance requirements, and what benchmarks should be employed. In general, the process roadmap would involve the preparation of annual plans indicating the areas that will be assessed and the schedules, the formation of self-assessment teams to carry out the reviews, conducting and documenting the assessments, analyzing the results, taking corrective actions, and communicating the status. This process would then be followed up by an evaluation of the effectiveness and quality of the review, as well as of the lessons learned for improvement.

Two types of gaps can be identified in this way, the first being where current safety requirements, regulatory or otherwise, are not being met and corrective actions must be taken immediately, and the second being where requirements are being met but there is opportunity for improvement. In this case, although the requirements are still being met, the performance may be trending away from acceptable standards. Ideally, it is the second type of gap that would eventually come to dominate the self-assessment process. This would demonstrate that the licensee was proactively determin­ing the precursors to any potential diminishing of safety and addressing them immediately. Therefore, self-assessments are a key activity for pre­venting operational complacency.

Analysis and feedback of operating experience is recognized as a valid tool to enhance safety in the IAEA Fundamental Safety Principles. By any measure, a nuclear power plant is a complex technology. The plant contains about 100 major systems that fall into four groups: nuclear systems, fuel and refuelling systems, secondary plant systems, and electrical systems. Due to ageing, configuration changes, and equipment upgrades, each of these systems requires verification on a continuous basis to ensure that the systems continue to meet safety and operational requirements. Operating experience, as part of the overall plant performance model, is a valuable tool for helping to ensure this, since it enables the licensee to apply previous information to anticipate and address issues before they occur. INSAG-21 has pointed out the importance of operating experience feedback for life cycle management and backfitting of nuclear facilities, as well as for improv­ing operating and regulatory practices, to enhance the global nuclear safety regime (INSAG, 2006).

Operating experience information covers all aspects of the NPP’s opera­tion and has implications for both plant performance and safety. With respect to plant performance, particular attention is paid to outages, planned and otherwise. Outages can be classified as planned (under operator control), unplanned (causes under operator control), and external (not under operator control). Planned outages include refuelling, inspection, maintenance, testing, and upgrades. Unplanned outages include those due to human error, equipment failure, operating margins, and regulatory/ licensing issues. Externally driven outages include grid failure following electricity demand, and environmental conditions.

The IAEA has established guidelines to enhance operating experience feedback (IAEA, 2006f). According to this Safety Guide, an effective system for the feedback of operational experience relating to safety should have the following elements:

• Reporting of events at plants

• Screening of events — primarily on the basis of safety significance

• Investigation of events

• In-depth analysis, including causal analysis, of safety-significant events

• Recommended actions resulting from the assessment, including approval, implementation, tracking and evaluation

• Wider consideration of trends

• Dissemination and exchange of information, including by the use of international systems

• Continuous monitoring and improvement of programmes for the feed­back of safety-related operational experience

• A storage, retrieval and documentation system for information on events.

The licensee should develop a comprehensive operating experience pro­gramme with input from a variety of internal and external sources. One international tool for operating experience is the Incident Reporting System (IRS) jointly developed by the IAEA and OECD/NEA (IAEA, 2008). The IRS reports contain information on NPP events that are of significance to safety and the safety lessons that can be learned to assist in reducing recur­rence of events at other plants.

More information on specific topics is also available. This includes an Information System on Occupational Exposure, which was started by the OECD/NEA and is now jointly maintained with the IAEA. Other projects at the OECD/NEA addressing specialized areas include the International Common-Cause Failure Data Exchange, the Fire Incident Records

Exchange, the Piping Failure Data Exchange, the Exchange of Operating Experience Concerning Computer Based Safety, and Stress Corrosion Cracking and Cable Ageing.

Another tool is the World Association of Nuclear Operators (WANO) series of documents on Operating Experience Report and Significant Operating Experience Report processes. However, WANO information is generally restricted to its members. There are also specific reactor tech­nology groups, such as the CANDU, Westinghouse, General Electric and KWU Owners’ Groups, which deal with design-specific operational feed­back, although some information may be restricted to group members. There are also national and regional institutions which interchange operat­ing experience.

In response to restrictions on some operating information that could impact safety, INSAG has pointed out in both INSAG-21 (INSAG, 2006) and INSAG-23 (INSAG, 2008b) that there is considerable room for improve­ment in the transparent sharing of safety information, both nationally and internationally. INSAG-23 also notes that:

It is widely observed in all fields of human activity that serious accidents are nearly always preceded by less serious precursor events. If lessons can be learned from the precursors and these lessons put into practice, the probability of a serious accident occurring can be significantly reduced. . . While the con­tinued strong safety performance by operators is encouraging, safety significant events continue to recur in nuclear installations. This indicates that operators are not learning and applying the lessons that experience can teach us.

As a result of their assessment, INSAG has proposed several recommen­dations to improve international operational feedback. However, imple­mentation of the feedback still rests with the licensee. It is important to ensure that operating experience is being used effectively throughout the licensee’s organization at all levels, and for both safety and operational performance. This includes the various processes for information gathering and analysis, experience application, auditing, and training.