Consultants, Clients and Contractors: How Effective Communication Can Improve the Seismic Qualification of Nuclear Facilities
Extreme Loads and structural risk
The Ultimate Cost: Time and Money
When the contractor’s installation team has not followed the design exactly or has cut corners, this generally comes to light during the interim or post-installation walkdown, when the works are nearing completion and the commissioning phase has or is about to start.
During the post-installation walkdown, a seismic review team is on-site to review the works from a seismic safety perspective. However, when items have not been correctly installed (or as per the design intent), problems occur; these problems often provide a cost and time implication to the client. Incorrectly installed items may need moving or replacing, and additional justifications and calculations may be required. In some cases, a further walkdown to confirm that any modifications or repairs have been made and satisfy the design intent may be necessary.
All this will cost the client time money. Certain deviations could add significant costs due to fixing or addressing the problem and delays in commissioning.
Our Recommendation: Ask Questions Now to Avoid Fixing the Design Later
My advice to contractors working in the nuclear industry is to ask questions or raise technical queries (TQs) promptly. If contractors cannot follow the design for any reason, they should contact the designer before completing the installation; it will save the client time and money and avoid embarrassing incidents.
One of the best features of ABS Group walkdowns is that we can go to the site on short notice and use our experience to review projects as they are happening. When our clients (or their contractors) come across a problem, it does not take days of calculations to resolve; once on-site, we can evaluate almost instantly. If we then need to perform calculations, we have all the necessary information to do so.
The Design and Installation Process in an Ideal World
The key to the ideal scenario is transparency on all parts. If the client brings us in at concept, we can discuss seismic requirements with the designer before they start. Then, we can perform an early design review and assess whether the design is suitable (from a seismic perspective). Following this, we can go to the site for a pre-installation walkdown, where the team (designers/client/operators) can walk and talk the route, looking for any potential concerns, ultimately dealing with any necessary design changes before installation begins.
Then, depending upon the size of the project, ABS Group can perform interim walkdowns. These would identify and resolve any site-led changes or unforeseen installation difficulties, such as heavy rebar preventing anchorage or scaffolding that has been put up in such a manner that prevents the drill from being used. When it comes to the post-installation walkdown, it’s more of a confirmatory sign-off.
This process can often prevent costly measures for the client. Although it may seem like an unnecessary cost at the beginning of a job, in the long run, it can prevent issues that may lead to delays in the start-up of a facility and save organizations large-scale costs at the end of a job.
ABS Group: Your Seismic Walkdown Experts
For the past 25 years, ABS Group has assisted a variety of clients and sites across a wide range of industries in both the U.S. and UK in completing successful reviews of safe shutdown systems and components utilizing the seismic walkdown methodology. Our engineers have significant experience and are widely recognized as subject matter experts. ABS Group has been instrumental in the compilation of earthquake experience databases, with access to all original records, allowing us to provide our clients with unique, cost-effective and practical solutions to resolving their pressing needs.