Cernavoda Unit 1 which is a newer plant having been in operation only since December 1996, started recently the development of Plant Life Management (PLiM) Programme. Due to its complexity, the programme plan has been divided in several subprogrammes and pilot projects and integrated with other initiatives for improvement in the long term strategy of Cernavoda NPP (2004-2008), and managed effectively by annual Station Technical Programmes.

A. III.1. MAINTENANCE ENHANCEMENT PROJECT

As a result of recommendations made by WANO/IAEA Mission in April 2000, Cernavoda is transitioning from “find & fix” maintenance to a “predict and prevent” strategy. The Mission recommended that Cernavoda NPP follow the EPRI3 recommendations while striving for a well integrated and optimized maintenance programme. Cernavoda NPP joined EPRI in March 2002, the required documentation (EPRI-NMAC4 Preventive Maintenance Basis Reports and similar) was secured and the Maintenance Enhancement Project was committed.

The process, as described below, is based on expert panel approach and depends on close collaboration of various departments within the power plant:

• Identify key equipment and components from critical systems (contributors to systems functional failures) and create a database

• Group key components by type and technical characteristics and identify applicable EPRI — PM basis/templates, manufacturer recommendations and current practice.

• For each type of equipment assemble an expert panel and carry out a comprehensive and systematic review of PM tasks and frequency.

• Review existing call-up work requests and maintenance procedures accordingly

During the expert panel interviews the System Engineer’s provided the worst-case effects on their systems and the station (if applicable) for failure of each of the “key” components they identified. In addition, failure modes and effects for components and equipment included in the Level 1 PSA study were also considered.

Over the last 4 years, as the Maintenance Enhancement Project progressed, the result was not only the enhancement of the maintenance programme but also a significant increase of the number of preventive and predictive maintenance tasks scheduled for the next few years and it became apparent that the programme must be optimized.

Therefore, in parallel with Maintenance Enhancement Project, the critical equipment list has been systematically screened to determine the essential equipment and components which by the virtue of their single functional failure would cause a unit transient/shutdown, a level 1 or 2 impairment and/or an unacceptable risk of asset damage.

The outcome of this initiative was identification of about 500 essential equipment and [6] [7] components throughout the station which represent the first priority for implementation of enhanced maintenance programme.

The next action carried out was the prioritization of maintenance activities based on the results of the vulnerability analysis of the unit to single failures of essential equipment. The vulnerability analysis was performed for so far for common equipment and components (valves, motors, pumps, electrical equipment, etc), with a software application developed by EPRI5 and the results was used for defining the scope of 2006 planned outage.

The general approach implemented in the vulnerability analysis software module is to benchmark the current surveillance, monitoring, inspection and maintenance tasks, time intervals and failure rates achieved since commissioning for each family of equipment and components, with an industry standard, state of the art programme and reliability targets developed by EPRI (EPRI PM Basis templates) and built into the PM database software.