Most nuclear plants throughout the world were built more than 20 years ago. It is not unusual for major components to begin experiencing age and corrosion-related problems. Nuclear plant executives increasingly are facing tough decisions that are complicated by the prospect, at least in the US, of extending their licenses another 20 years. Deregulation is one factor driving nuclear power plants to increase their output, reduce costs and operate at peak efficiency. As a result, the market for replacement components is growing. For example, in 2001, there were approximately $75 million to $100 million in orders in the US. Forecasts call for orders to increase to approximately $200 million for the next three years.

Accumulator under construction at the Chalon Saint Marcel facility

Until recently, when normal wear or corrosion-related problems surfaced, the decision to repair was relatively easy. Today, however, these aging plants are being forced to spend increasing amounts of time and effort in analyzing the pros and cons of repairing or replacing. If repair is performed, how long will it last? Is it cost-effective? Over what time period? If the plant intends to extend its license another 20 years, what impact does that decision have on the repair/ replacement equation? If a decision is made to replace a component, then the issue becomes managing the existing component in such a way that maximum efficiency is maintained during the time it takes to manufacture the new component. Framatome ANP is the premier supplier in the world who can help plant management through the entire process: initial inspection and analysis, evaluation and cost/risk analysis, engineering for the actual manufacturing and installation of a replacement component.

Replacement Often Most Cost Effective

Components that are particularly susceptible today are reactor vessel (RV) heads and steam generators (SG). The susceptibility of Alloy 600 to water corrosion causes numerous problems for these components. In the past, one solution for SG problems was plugging tubes or sleeving tubes to restore their efficiency. However, only so many tubes can be plugged before capacity is affected. In addition, inspection (and repairing) of tubes at every outage significantly impacts cost and schedule. Since the original SGs were installed, improved materials for tubes have been developed that are less susceptible to corrosion. These new developments directly impact the analysis of the repair versus replacement equation.

Many plants are opting to replace major components rather than continuing to inspect and repair them because of the overwhelming positive impact to their operational budgets, particularly if the plant intends to file for license renewal.

Two US Plants Opt for Replacement

Callaway, a US plant owned and operated by AmerenUE, recently ordered four steam generators from Framatome ANP to be delivered in 2005. When asked why they chose Framatome ANP, Tim Herrmann, Superintendent Engineering Steam Generator Replacement and Project Manager for SGR, commented, "Framatome ANP offered an innovative design that supports our needs and enhances our plant... We came to Framatome ANP with one frame of reference and left with a different and better solution."

Callaway's steam generators will be manufactured in Framatome ANP's Chalon Saint Marcel manufacturing plant, the foremost reactor component supplier in the world, with 90 units manufactured and installed. Callaway personnel, while visiting that facility, were impressed with the attention to detail, the clean room, and the constant inspection and analysis during each step of the manufacturing process. Since Chalon Saint Marcel has established a web server for communicating design specifications, engineering documentation and manufacturing progress, customers can access information on their particular component in real time.

In 1999, the Chalon Saint Marcel plant delivered a reactor pressure vessel as well as three steam generators and a pressurizer to the Ling Ao Unit 1 station in China and another to the Ling Ao Unit 2 station in 2000. They completed construction of the two Civaux 1450 MWe N4 units in 1997 and 1999. They currently are fabricating two replacement steam generators for Prairie Island that will be delivered in 2004. Of the 28 new LWRs (non VVER) that have been started up since 1990, 13 were built by Framatome ANP.

Chalon Saint Marcel Manufactures Only Nuclear Components

Established in 1975, the Chalon Saint Marcel facility has fabricated over 400 PWR heavy components, including reactor pressure vessels and internals, steam generators (272), pressurizers (68), reactor vessel closure heads (113), accumulators, piping for reactor coolant systems and component support structures. Due to the facility's flexible design, the demands of multiple customers, i.e. multiple types of components, can be manufactured simultaneously.

Reactor vessel leaving Chalon Saint Marcel for installation at Civaux

Because the facility has continuously manufactured only nuclear components, all R&D efforts focus on improving the technology, welding techniques, and materials used in the components. In particular, the Technical Center specializes in welding and related technologies as well as metallurgy and surface treatment. Their non-destructive examination (NDE) innovations and technologies ensure minutely detailed inspection of all component parts and welds. The Center also analyses corrosion chemistry and develops new materials to minimize its effects.

Ling Ao steam generator

Design automation, engineering and manufacturing are the key to the Chalon Saint Marcel's reputation for quality and service. Deep-drilling machines for tubesheets, multi-spindle drilling machines for tube support plates and automated broaching machines ensure uniformity and consistency. Controlled access and pressurized clean rooms for the tube installation process (tubing, welding, hydraulic expansion, etc.) ensure that no foreign materials are introduced into the steam generators during the manufacturing process.

Framatome ANP's wealth of worldwide experience in service, engineering and maintenance helps customers effectively manage their aging plants. If replacement components are required, the premier nuclear heavy component manufacturing facility in the world can manufacture them to the customer's specification at a competitive cost, deliver it on time, and ensure that the installation requires minimum outage time. Framatome ANP, through its extensive experience and expertise, can assist customers beginning with the decision analysis process through purchasing, licensing, manufacturing, installation and follow-on service for the life of the component.

Multi-spindle drilling of tube support plates ensures uniformity and consistency