SEISMIC QUALIFICATION | SAFETY
During the post-installation walkdown, a seismic review
team will be 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, with significant cost and time implications. Any incorrectly installed items may need to be moved or even replaced, and additional justifications and calculations may be required. In some cases, a further walkdown may be necessary to confirm that any required modifications or repairs that have been made do actually now satisfy the design intent. Certain deviations could also add significant costs due to fixing or addressing the problem and may even cause delays in commissioning.
Ask questions now to avoid problems later It sounds obvious, but our advice to contractors working in the nuclear industry is to ask questions or raise technical queries (TQs) promptly. If contractors cannot precisely follow the design for any reason, they should contact the designer before completing the installation. This will save the client time and money and avoiding potentially embarrassing incidents. Walkdowns on site, even at short notice, are able to use
experienced seismic engineers to review projects as they are developing, enabling accurate evaluation of any issues
before they become impactful problems, helping prevent the time and cost issues that could arise. The key to the ideal design and installation process is
transparency from all parties. If the client brings in seismic engineer at the concept development stage, seismic requirements can be discussed with the designer before they start. Then, an early design review can be performed to assess whether the design is suitable (from a seismic perspective). Following this step, site visits for a pre-installation
walkdown can be arranged, where the team (designers/ client/operators) can walk and talk the route, looking for any potential concerns, and dealing with any necessary design changes before the installation actually begins. Then, depending upon the size of the project, interim
walkdowns can be performed to 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 it prevents the necessary drill from being used. If this rigorous approach to seismic qualification is adopted, when it comes to the post- installation walkdown, it’s more of a confirmatory sign-off. 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. ■
Nuclear Science and Technology
MSc - 1 year full time MSc - 2 or 3 year part time Short Courses for CPD
Designed to create a generation of nuclear engineers and scientists with the skills to secure a sustainable and safe future for nuclear energy.
Key features: Demand-driven • Breadth of learning • Delivered by experts • Flexibility • Short-course format
www.neimagazine.com | June 2023 | 31
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49
