SAFETY | SEISMIC QUALIFICATION
Communications and validation of seismic qualification
Consultants, clients and contractors should remain mindful of common issues that can impact the validity of the seismic qualification on their installations. This key safety issue can often be addressed with effective communications
By Andrew Buckley, Principal Engineer, ABS Group, UK
WHEN ADDRESSING THE SEISMIC QUALIFICATION of plants and equipment, one of the most common problems identified is installation deficiencies. This is not to say that the installers (contractors) are not doing a good job; they are just not always installing equipment exactly as per the design. Changes in the position of a bracket or bolt, or the orientation of a support, however small, can negate the design qualification status. When consultants are performing a technical assessment of a design, they perform calculations and, in some cases, run Finite Element Analysis (FEA) models to ensure that the design meets the requirements set out by the client. This numerical method is generally used to support the design, substantiation, or investigation of various structures, including buildings, plant and equipment. These kinds of analyses provide a clearer understanding of the physical behaviour of a complex object and produce an optimal design, based on the predicted performance and behaviour of the design. It is a technique that is able to calculate the safety margin whilst accurately identifying any weakness within the design.
Once completed, these designs are then passed to the client and installer. It is at this stage where the communication triangle between consultants, clients and contractors can begin to breakdown.
Factors in communication breakdown Knowledge at the installation phase of a project is essential and the communication workflow around this is critical to the success or failure of an installation. Why something has been designed in a certain way has to be communicated at every phase of the process – from source to manufacture through to installation. Any small change being made by any one person at any
phase of the process may not have a perceived impact, but ultimately can completely change the seismic response of an item or make surrounding equipment a costly interaction concern when it previously was not. However, not all deficiencies emerge because of changes in design, manufacture or installation; some result from human error that can occur when communicating under the squeeze of a project timeline and supply chain pressures. Experience has shown that contractors – new to the
nuclear industry – are potentially qualified to complete “regular” installations but it is recommended that an independent third party is used to assess the technical expertise in the contracting team to ensure they have the proper experience to work in nuclear facilities. This can help to overcome issues of corners being cut and missteps taken. Installation jobs must be executed correctly and need
to meet the required standards. Again, this is where verification and certification by a third party organisation can ensure installation procedures and standards have been met. No installer or asset operator wants to incur the cost of delays and project downtime if problems are discovered at the start-up operational phase, which could have been overcome at an earlier phase and at far less cost.
Above: Ensuring installations are qualified to seismic standards requires good communications
30 | June 2023 |
www.neimagazine.com
The cost of poor communications 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.
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