A visitor to a control room in a nuclear power plant can find tables and drawers that, at first glance, could seem to be from any type of office. The tables have monitors, keyboards, telephones, and other computers and communications devices atop them; and the drawers house drawings and documents. It´s like any other office.
Nevertheless, the furniture of a control room is quite different from that of an office. In the event of an earthquake, these pieces of furniture must remain in place and cannot move: they must retain their physical integrity and be prevented from flying out. Therefore, this is furniture with seismic qualification.
The Design is Important
The requirement of seismic resistance for each piece of furniture is considered early on in the design phase. Figuring out how to attach each element to its structure and how the piece of furniture itself will be attached to the control room’s floor are just a few examples of the challenges that designers face.
Additionally, the answer to these challenges cannot negatively affect the furniture’s functionality and ergonomics.
A Controlled Earthquake
Once the most suitable design has been hashed out, it is important to ensure that the furniture that has been designed meets the requirement of being earthquake resistant. To do that, a prototype is made using the same processes and the same materials as those that will be used for the real piece of furniture. The prototype is assembled on a test bed that can move about like the floor of the control room in the event of an earthquake.
In these seismic tests, the prototype is subjected to movements from the worst-scale earthquake that can be expected in the region where the nuclear plant is located. And this is not just done once: it’s done several times.
If the prototype remains intact and none of its parts fly out, then we can be sure that the real piece of furniture will also remain intact in the event of a true earthquake.
What if I have pieces of furniture that are similar but not the same?
Do I have to repeat the tests? In this case, engineering provides us with more efficient and less expensive solutions than fabricating a prototype for each piece of furniture and undertaking seismic testing again and again.
A computerized virtual copy of the exact furniture design can be used to undertake simulations of the forces to which the furniture would be subjected during an earthquake. In this way, an estimation of the furniture’s behavior can be obtained. Additionally, behavioral data from a single battery of seismic testing on a prototype is also available. All of that is studied, analyzed, and conclusions are drawn about the expected behavior – especially in terms of structural strength and resistance.
To furnish the control room in a nuclear power plant, you just can’t stop by the local furniture store, choose a piece of furniture, and have them come by to set it up wherever you want. It is necessary to follow a meticulous seismic qualification process that starts with design and doesn’t wrap up until the piece of furniture is properly installed in the location and position where it has to go.