Showing posts with tag Nuclear

On using CAV and OBE in seismic monitoring of nuclear power plant

Posted on Sep 24, 2014 in News

Operating basis earthquake ground motion (OBE) is the ground motion for which those features of the NPP necessary for continued operation without undue risk to the health and safety of the public will remain functional (NRC Regulations, Appendix S to Part 50—Earthquake Engineering Criteria for Nuclear Power Plants). The operating basis earthquake ground motion is only associated with plant shutdown and inspection unless specifically selected by the applicant as a design input. Parameters of the OBE are estimated on the basis of integrated geologic, geophysical, and geotechnical investigations.

The USNRC (U.S. Nuclear Regulatory Commission 1997) uses standardized CAV (cumulative absolute velocity) as one of the ground motion measures to determine whether a nuclear power plant must be shut down after an earthquake when the OBE ground motion is exceeded. Standardized CAV (EPRI 2006) is used in conjunction with response-spectral acceleration and velocity, and is a measure of a potential damage. CAV is calculated from the acceleration time history using integral formula by means of the standardized procedure (EPRI 2006).

For OBE exceedance to occur, the recommended criterion requires exceedance of both a response spectrum parameter and a damage parameter, referred to as CAV.

Weir-Jones, and our manufacturing arm Terrascience, has been maturing with the nuclear industry for many years. We have many of our analog seismic monitoring systems out, all over the world, and they run as well today, as they did when they were installed. we have, of course, grown with the industry as well, and this is shown in the evolution of our equipment for analog beginnings to pure digital accelerometers, recorders and software.

The above note outlines the criteria we have deployed in our acquisition software, AUTOTAR, to accommodate the required CAV measurements that all operating nuclear power plants (NPP) rely on for continued safe operation. We are very excited to see our clients update their analog systems to full on digital systems with our new software packages. Most exciting indeed!

Tags: NRC, Nuclear Power Plants, CAV, seismic monitoring

A voyage through the Western United States

Posted on May 28, 2014 in News

Hello all!

We are just back from a six State, 5000 km (3000 miles for our Imperialist friends...) run down to Scottsdale Arizona and back again, after of course we finished showing accelerometers and strong motion recorders at the Nuclear Energy Assembly. It was quite an eye opening experience.

As it turns out, there hasn't been a lot of movement in that industry for 30 years or so; no one has built plants in North America, and no plants have really been hiring a lot of people until lately. So, this has created a large gap between the guys who are retiring, and the new guard that are just coming online - it was fascinating to listen to the stories, and the air was electrified (no pun intended...) with new technologies, new ideas, and very forward thinking folks that appear to be really driven to shine.

All told, we made some new friends that I hope will remain so for many years to come.

Now, did anyone know that when you drive into Nevada, go through Vegas, and then head north to Reno that you drive by Area 51 for about 300 miles???!!! Nor did I, and I was most unhappy that our American friends did not have any aliens on display for us to see, except for a weird shop in the middle of nowhere, which seemed somewhat suspect and not government sanctioned:


Needless to say, the green guy on the storefront was the only alien-y thing we saw.

I will have more on this trip in coming posts!


Tags: , accelerometers, structural monitoring, strong motion, nuclear

Back from a trip to Arizona!

Posted on May 25, 2014 in News

Hi All!

I am back from a whirlwind trip down into the States to create awareness of our accelerometers and their uses!

There will be more from me, but seeing as though it is Sunday, it will have to wait until tomorrow!


Tags: , Nuclear, acceleromters

Torquers, torquers, torquers...!

Posted on Apr 16, 2014 in News

Accelerometers... single, dual or tri axial - we make them, we service them, we ship them worldwide; and we are very proud of that fact.

Production is just ramping up again (after the move), but we will continue to support our clients in the nuclear, heavy construction and property markets. Property you say? Well yes, our Shake Monitor product is primarily used to monitor long term settlement, pre/post incident auditing and reporting, and is basically a proven system for monitoring structures. Very neat stuff!

We hope that Rudy, Rhoda and Sam can continue to tweak production as they have been doing!

Very soon Iain and Lincoln are going up to Anchorage Alaska to attend a conference to showcase these products and our technical capabilities.


Oh, it is going to be a very busy summer!

Tags: , accelerometers, structural monitoring, strong motion, nuclear