27. Meeting in Paris

Plant Integrity Challenges in ESB Power Generation - Richard Sheehan, ESB

OVERVIEW
The presentation set out to give a general overview of the issues that arise with plant age. Plant age issues are indeed a source of concern in most international utilities where plant units are now approaching or operating beyond original design life.

The presentation set out to give some examples of plant integrity incidents in international plant, as well as citing some plant integrity issues in ESB.

Finally the presentation would talk at a high level about the management strategy adopted in ESB Power Generation designed to manage plant age issues.

PLANT INTEGRITY – WHY THE CONCERN?
The management of plant integrity is of concern for a number of reasons, including

• Ensuring Personnel & Plant Safety
• Environmental Protection
• Statutory Obligations
• Plant Availability
• Risk Management
• Cost of plant failures

SOME INTERNATIONAL FAILURES

Failures due to plant age, including

• Mount Storm steam line seam weld failure
• Irsching LP rotor failure
• Generator rotor failure (where?)

LEGAL CONSIDERATIONS worth considering
Aside from compliance with statutory obligations, a utility should demonstrate that it has proven

• Compliance with Best Industry or International Practice
• Regularity of checks and Extent of checks
• Learning from previous incidents
• Approach based on Prudent Standards

PLANT AGE CONCERNS

In ESB

• Plant originally designed for 100-150K hours
• Now running at 150-200K hours - now also an international phenomenon
• Damage Accelerates - i.e. crack propagation accelerates with age
• Severe plant running regimes being introduced (faster start-ups, cycling regimes)!

DAMAGE MECHANISMS
There are diverse and complex damage mechanisms acting on various plant components. It is necessary to understand the mechanisms, to quantify damage rates and critical flaw sizes to quantify remaining life.

• Fatigue
• Creep
• Creep-Fatigue
• Stress Corrosion Cracking
• Corrosion
• Corrosion Fatigue
• Fretting
• Wear
• Erosion
• FAC
• Embrittlement

REDUCED MAINTENANCE OPPORTUNITY
Graph shown of reduced maintenance opportunity, despite the additional concerns brought on by plant age!

SOME ESB INTEGRITY ISSUES

• Steam Pipework - weld and bend creep-cavitation and cracking
• HP Rotor - fatigue cracking at rotor serrations

MANAGEMENT STRATEGY
An optimised management strategy is required to counteract plant age issues. In ESB Power Generation, this strategy has involved:-

• Developing a robust technical management framework, stemming from corporate policies to local station technical procedures
• Benchmarking with other European utilities
• Carrying out technical risk assessments by external auditors
• Involvement in EU funded projects on risk-based inspection and maintenance
• Development of robust 7-year plans within stations to manage technical issues
• Emphasis on life assessment of critical plant items

Richard Sheehan

Equipment obsolescence management - Antoine Despujols EDF
An increase of equipment obsolescence cases is observed and this trend is probably going to continue in the future. It’s the reason why a project is carried out at EDF on equipment obsolescence management. One of the tasks of this project consists of a benchmark survey of methods and practices. By obsolescence, we mean "technological ageing" from commercial, technical or regulatory viewpoints, and by equipment we mean components, sub-systems or complete systems covering not only I&C equipment but also valves and electrical, mechanical, lifting equipment,...
A questionnaire was written to cover different points:

• Organisation in charge of this.
• Strategy: reactive to detect obsolete components, or proactive to identify components that are not yet obsolete but may become so.
• Obsolescence detection in case of reactive and proactive strategy.
• Priorities of obsolescence cases.
• Treatment.
• Other information on: the use of data bases, obsolescence of knowledge, qualification of new components, collaboration with other companies to share information or resources, etc. .
  This benchmark is expected to provide good practices and a guideline will be written on equipment obsolescence management.

Market Driven Commercial Performance Measures - Alan Joslin - InnogyOne

Commercial performance measures serve a different purpose to technical ones. Technical measures describe performance in engineering and operational terms, but although good technical performance usually means that commercial performance is also good, this is not always the case, and the converse is often not the case. It is possible to achieve good commercial performance with significantly worse technical performance.

Commercial performance measures should take account of both costs and revenue, and are thus very dependent on the market in which the plant is operated. Innogy, and its predecessor National Power, developed a set of commercial measures that were applied as KPIs to its own position as a fleet owner/operator in a pool market. Some, but not all, of these measures could also have been applicable for an IPP operating in the same market.