Advanced computer design tools have merged with high-definition laser camera scan data to produce integrated images that are particularly useful for outage and maintenance planning. A 3-D tool that enables a project team to perform virtual equipment removal or installation is essential when each extra day of actual labor adds millions of dollars to outage costs. Here’s an example of how it works.
Planning for a major maintenance outage usually begins one to two years in advance of the work when major equipment overhaul or replacement is involved. A good example is replacement of a steam generator in a typical pressurized water reactor plant. An essential part of that outage planning process will include determining the crane design required to lift the new steam generator into place and skid it into the containment vessel. The real challenge comes when the old vessel must be cut out, interferences removed, and proper rigging points identified. These aren’t chores that can be handled on the fly, especially given that construction (and deconstruction) process planning and close craft and equipment coordination are vital as outage intervals continue to compress.
The design engineer must have accurate plant documentation showing the location of every pipe and conduit so that the least-invasive path can be selected for large equipment removal. However, chances are your plant was designed in an era when only 2-D computer aided design (CAD) design tools were available. Although it’s unlikely, let’s hope your paper drawings were accurately updated after construction to show the plant’s as-built configuration. Chances are that after a few years, your plant drawing database contains some inaccuracies.
One technology that solves the plant design documentation dilemma is laser scanning. Laser scanning is a very effective and efficient approach for developing very precise digital as-built documentation of even the smallest details found in a power plant, especially those areas that are difficult to access during operation or where access is available for only short periods. In fact, you can measure distances and other key dimensional data directly from a digital scan (Figure 1).
1. Digital diagrams. A laser scan of a typical equipment room can be supplemented with scaffolding, dimensional data, and components to be removed, thereby serving as part of a comprehensive overhaul or replacement planning tool. Source: CSA Inc.
Laser scanning also provides a dimensionally accurate representation of the plant and all its equipment as well as a photographic quality visual representation. The laser scan database can be integrated with a variety of plant design applications to provide comprehensive facility management support.
In fact, a laser scan 3-D database can be combined with the 3-D CAD tools now becoming more common to develop a comprehensive representation of a facility. This virtual view of a plant can now be used to explore alternative equipment removal evolutions, scaffolding management, or rigging sequence planning and training. It can even be integrated with other radiation-monitoring technologies. Also, for a nuclear plant planning an outage, complete equipment removal and replacement simulations can be performed to identify construction and access problems when they are easily resolved, rather than when a hole is open in the containment building.
There are other less-obvious uses of laser scanning for new plant construction. For example, scanning might be used to document areas and components that would be closed or inaccessible after completion of construction. It could also document construction tolerances, design, and installation of components that are traditionally field-routed (such as small-diameter piping, tubing, conduit, and the like). You could even scan a completed facility to create comprehensive as-built documentation for use by plant operation and maintenance staff during commercial operation.
Close integration
Previously, 3-D modeling was used extensively to support the planning and design of major equipment removal or replacement projects. The difficulty with 3-D modeling alone was that it required almost perfect design documentation of the removal path, and creation of a 3-D model was relatively expensive and time-consuming.
In contrast, 3-D laser scanning represents a considerable improvement by reducing costs and eliminating the need for stacks of plant drawings and equipment specifications. Laser scanning is a quick mechanism for capturing a comprehensive representation of the area in question and the areas affected by the removal and reinstallation of an equipment item. Its documentation also provides a very effective representation of the space that can be well-integrated with many 3-D CAD systems.
Email
Comments
Print
Reuse
