wireless

Wireless technology is experiencing explosive growth. More than just devices of the same kind, there is a proliferation of applications that take advantage of wireless connectivity, using it in new and novel ways. Wireless technology itself is developing and radio access technologies are becoming increasingly complex and sophisticated. The result is that today’s electromagnetic environment is changing. This means that old test methods and limits are no longer adequate to insure systems have adequate electromagnetic immunity.

Utilities operating nuclear power plants have been dealing with electromagnetic interference (EMI) problems for over two decades. Many early problems that affected the operation of instrumentation and control (I&C) equipment in plants stemmed from the use of wireless transmission devices (WTDs) (e.g., radio walkie-talkies, cellular phones, etc) inside the plant in the vicinity of system cabinets and cable trays carrying bundles of cables. A simple and partially effective method of reducing EMI events caused by WTDs has been to mark off exclusion zones around system cabinets and areas where I&C equipment is installed. The use of these zones has presented some problems for existing plants. For example, some plants have had to expand the area of some zones that became ineffective upon the use of new WTDs that evidently presented an increased risk to the operation and EMI protection of I&C equipment. The sizes of some expanded zones are larger than 2,000 square feet. In addition, some zones encroach upon human traffic areas used by plant personnel to move from area to area within a plant.