Maintenance - A Design Perspective

Abstract

A successful nuclear program requires a plant to have a long life and a high capacity factor for the duration of that life. As the plant matures, there is a need for a balancing and optimization among corrective, preventive and predictive maintenance programs depending on the age of the station. However, design is the starting point, and a successful plant requires god design, attention to detail, and allowance for maintenance and rehabilitation, including facilitation of the replacement of some components. The paper describes how AECL's new reactor design, the CANDU 3, has incorporated, at the design stage, maintenance requirements such as component accessibility, standardization, ease of replacement, reduction in the number of components, and simplified component design. Two processes that contributed greatly were the involvement of utility staff in the design, and the carrying out of formal design reviews, including a maintenance assessment. Such processes resulted in many changes to the CANDU 3 design, including numerous layout changes to improve maintenance access. Existing plants must have excellent support when Important components have to be replaced, refurbished or rehabilitated. AECL is playing a key role in the planned rehabilitation of Ontario Hydro's Bruce A nuclear generating station's four units. In addition to conceptual design and development, detailed design and analysis, procurement and site assistance, AECL's Sheridan Park Engineering laboratory (SPEL) will provide important development and mockup facilities. Research and Development also plays an important part in maintenance of station performance. A long term strategic plan is described whose objectives include the identification and characterization of aging and degrading mechanisms; the tailoring of developed products to plant requirements; and the identification of areas of international cooperation and information exchange. It is dear that, from the designer's perspective, there is the requirement to consider the needs of maintenance throughout the complete life cycle of a nuclear plant, and to bring to bear the complementary aspects of their resources, be they design, test facilities, or R and D, as the plant matures.