Wireless technologies have increased efficiency in many industrial settings across the world by enabling a mobile workforce, improving communications, optimizing maintenance, and enhancing safety and security. Nuclear facilities stand to benefit through wireless implementation as well, but because of safety, security, and reliability concerns sites have been slow to adopt wireless technology. Additionally, the possibility of electromagnetic interference (EMI) resulting from wireless implementation has hindered the deployment of wireless technologies in nuclear facilities. To help the industry address these concerns, AMS has developed expertise and services to assist any nuclear facility implementing wireless technologies. AMS offers a comprehensive approach for wireless implementation through site walkdowns, sensor selection assistance, laboratory testing, EMI/RFI site surveys, and in-situ immunity testing. These techniques can be used to reduce overly conservative exclusion zones, identify equipment sensitive to EMI/RFI, and ensure safe use of wireless throughout a nuclear facility.

In order to expand the use of wireless technologies throughout the power block, one nuclear power plant recently undertook a three-step approach with AMS to ensure that no EMI issues occurred due to the use of wireless devices. The approach included:

1. Performing walkdowns and visual evaluations of the installation of the existing plant equipment
2. Characterizing the electromagnetic environment within the plant through an EMI/RFI site survey
3. Performing targeted immunity testing of select plant equipment to provide data driven exclusion zones

To aid the site, AMS performed a site walkdown to evaluate the installation of sensitive/critical equipment throughout the plant for vulnerabilities to EMI from wireless devices. During the walkdown, aspects such as grounding, shielding, use of conduit and cable trays, and exposed signal leads were inspected, and a list of vulnerable equipment was developed. Numerous pieces of equipment were identified that had either vulnerable installations, were critical to plant operation or safety, had a history of malfunction in the presence of wireless devices, or could cause nuisance alarms for plant operators.

After the walkdown, AMS performed EMI/RFI site surveys of the selected areas to characterize their electromagnetic environment and determine what level of emissions currently existed. EMI/RFI site surveys are used to aid wireless implementation by identifying the source of frequencies that may compete with wireless devices, determining if the existing electromagnetic environment negates the need for immunity testing, and locating sources of frequencies that may indicate vulnerabilities of equipment. During the mapping, AMS identified several pieces of equipment with emissions in the frequency band of wireless devices, and those systems along with other critical plant systems were selected for in-situ immunity testing.

In-situ immunity testing is performed using a modified radiated susceptibility test typically used for qualification testing of new equipment. Radiofrequency energy is radiated onto equipment and cables within a facility to objectively measure its response to EMI. Preventative measures such as shielding are put in place so as not to interfere with any nearby equipment that may also be vulnerable. This targeted immunity testing was performed on the previously identified systems at the nuclear facility and the results were used to objectively determine each system’s immunity to wireless devices. The results of the testing at this particular site concluded that a majority of the equipment was immune to the wireless signals of concern, with the exception of various pressure transmitters and radiation monitors. With this knowledge, the site implemented administrative procedures to limit the potential for EMI for those systems. Using the walkdowns, emissions testing, and radiated susceptibility testing, the site engineers gained knowledge of plant equipment and how the plant equipment may respond to wireless signals which provided objective evidence and increased confidence that no issues would occur during wireless implementation.

Example Applications of Wireless Technologies for Efficiency Gains:

1. Tablet Based Work Orders and Calibration Procedures
2. Wireless Access to Site Engineering Documentation
3. Voice Communication Anywhere in the Site
4. Temporary or Permanent installation of Wireless Cameras
5. Equipment Condition Monitoring Using Wireless Sensors
6. Wireless Dosimetry

As the use of wireless technology expands in nuclear facilities, sites will need increased assurance that wireless will not cause any adverse effects when implemented and help to reduce exclusion zones that may limit the use of wireless devices. AMS offers implementation assistance, objective testing to determine equipment vulnerabilities, and engineering expertise to ensure that any wireless implementation is successful, safe, and secure.

Interested in learning more about our wireless implementation services? Please call 865-691-1756 or email info@ams-corp.com today!

AMS Participation in Guidance and Standards Related to Wireless Technologies:

• IEC 62988, “Nuclear Power Plants – Instrumentation and Control Important to Safety – Selection and Use of Wireless Devices,”
• IEC 62003, “Nuclear Power Plants – Instrumentation, Control, and Electrical Systems Important to Safety – Requirements for Electromagnetic Compatibility Testing.”
• International Atomic Energy Agency (IAEA) Coordinated Research Project, “Application of Wireless Technologies in Nuclear Power Plant Instrumentation and Control Systems.”
• EPRI TR-102323 Revision 5, “Guidelines for Electromagnetic Compatibility Testing of Power Plant Equipment.”
• Implementation Guideline for Wireless Networks and Wireless Equipment Condition Monitoring, EPRI, Palo Alto, CA: 2009. 1019186.
• Wireless Sensor Survey and General Specification, EPRI, Palo Alto, CA: 2018. 3002011818.