Electromagnetic Interference and Compatibility
Electromagnetic signals can produce malfunctions at the component, equipment, subsystem and system level if not properly controlled and compatible with their environment. These disturbances created by either natural (lightning, Electrostatic Discharge (ESD), etc.) or man-made sources (radio transmissions) present I&C design, maintenance, and reliability challenges when electromagnetic interference (EMI) affects either safety or non-safety and important to power production functions. These malfunctions can result in time consuming delays, forced outages, or other severe consequences. Hence, electromagnetic Compatibility (EMC) and the practices that promote compatibility play an important role in managing the I&C equipment lifecycle and promoting equipment reliability.
The following Wiki provides an outline of existing EPRI EMC guidance related to the following topics:
Background[edit]
System and component EMC refers to the equipment’s ability to function, as designed, without adverse degradation or failure due to interference sources operating in its intended environment. EMC also refers to the equipment’s ability to function without adversely affecting other equipment connected to or located in that environment.
Emissions, whether deliberate or unintended, are electromagnetic energy generated by one or more radiating or conducting sources. This energy is released into the ambient environment which can create EMI. EMI can degrade or cause failures of equipment in the surrounding area or within a device or its enclosure.
EMC assessment is a process that involves:
- Understanding anticipated continuous-wave and transient emissions in the environment where equipment will be installed
- Selecting a device or system that is intended to be compatible with the environment
- Evaluating the immunity of the device or system to ensure it will perform reliably as designed when exposed to expected electromagnetic emissions
- Evaluating the emissions of the device or system to ensure it does not exceed acceptable thresholds thus creating the potential to cause interference with existing equipment local to the point of installation
- Installing and maintaining the system as intended for an acceptable level of EMC
Reasonable assurance of EMC can be achieved by satisfying each of the bullets above.
EPRI Guidance and Training on EMC Fundamentals[edit]
EMC Handbook[edit]
EPRI's Handbook for Electromagnetic Compatibility of Digital Equipment in Power Plants is a dual volume publication that is available to the public. The handbook explains the fundamentals of electromagnetic compatibility and provides guidelines for ensuring the electromagnetic compatibility of digital equipment in power plants. The handbook is applicable to digital equipment being installed in all types of power plants.
- Volume 1 - Fundamentals of EMI Control: presents a comprehensive and theoretical discussion of the fundamentals of EMI control. This volume is a reference to assist the reader in answering questions encountered and to fully understand potential and existing EMI problems.
- Volume 2 - Implementation Guide for EMI Control: presents a practical implementation guide for EMI control, beginning with design and procurement through testing and installation; it also includes information on operation and maintenance.
Training Materials[edit]
EPRI provides training on EMI & EMC fundamentals and its guidance documents addressing the subject, browse EPRI Training and Development Platform for future guided training opportunities.
For self-paced learning opportunities on the topic, review:
- Engineering Technical Training Module (ETTM) - EMI and RFI Noise Analysis, Version 1.0: a computer based training course that provides training for power plant engineers on the types and characteristics of electrical disturbances found in a power plant environment.
- EMI Qualification of Digital Equipment Upgrades - Revision 2, Version 3: a computer based training course that presents the recommended generic EMI susceptibility and emissions test levels for use in establishing equipment EMC for nuclear power plant applications.
An instructor-led EMC fundamentals training is in development and will be available from EPRI in the future.
EPRI's Guidance on EMC Testing and Control Method Allocation[edit]
EPRI’s EMI testing and control method allocation guidance resides in two flagship products that are further described (motivations and evolution) in the following sections:
- Guidelines for Electromagnetic Compatibility Testing of Power Plant Equipment (TR-102323), and
- Electromagnetic Compatibility Assessment Methodology (EMCAM)
Guidelines for Electromagnetic Compatibility Testing of Power Plant Equipment (TR-102323)[edit]
The initial version of EPRI Guidelines for Electromagnetic Compatibility Testing of Power Plant Equipment, referred to as TR-102323, was focused on stabilizing the licensing process associated with U.S. nuclear plant digital I&C equipment upgrades. The initial publication addressed the following fundamental concepts:
- Recommended electromagnetic and radio interference (EMI/RFI) susceptibility testing levels
- Recommended equipment emissions testing levels
- Recommended design and installation practices
Future revisions to TR-102323 up to and including the current revision 5 build on those fundamental concepts. See TR-102323 table below for a list of versions of this guidance with descriptions of the main changes between them and links for access in EPRI website.
The TR-102323 methodology and recommended testing limits accomplish the following two objectives:
- Ensure equipment susceptibility limits bound measured plant emissions levels by a margin of at least 8 dB or more (see Bounding Plant Emissions figure below). The 8 dB susceptibility margin was required to obtain U.S. Nuclear Regulatory Commission (NRC) endorsement for “Guidelines for Electromagnetic Compatibility Testing of Power Plant Equipment” Revision 1 to EPRI TR-102323.
- Establish one set of bounding equipment susceptibility and emissions testing limits to qualify equipment one-time for use in any commercial power plant in any location.
In addition to recommending susceptibility limits that support one-time qualification testing that bounds plant emissions, TR-102323 also provides a graded approach for testing systems based on safety classification and the potential impact to plant operations. Table 5-1 Testing Applicability on TR-102323, documents a complete suite of susceptibility type tests applicable for safety related applications, recommends the same suite of susceptibility type tests for applications that are non-safety related and important to power production, and provides optional susceptibility testing guidance for other non-safety related applications. Table 5-1 also documents applicable high-frequency conducted and radiated equipment emissions testing for each of the aforementioned applications.
This provides assurance that new equipment installed in a facility, regardless of its safety classification, will not interfere with safety-related equipment.
The TR-102323 methodology provides high assurance of EMC and attempts to reduce the need for subsequent re-qualification based on a modified use case. While this can eliminate the need to repeat susceptibility or emissions testing to different testing levels for each application, qualification to lower susceptibility or higher emissions limits may be technically acceptable and also reduce qualification costs in certain applications.
TR-102323 versions access table[edit]
| Revision # | Publication year | Revision notes |
|---|---|---|
| Revision 5 | 2024 (Errata)
2019 |
The latest revision, incorporates all learnings from past versions and contains in the appendixes the technical bases for the changes. It also adds additional guidance and clarification to various sections of the document based on current events and issues experienced by the nuclear power industry. This includes the addition of an example exclusion zone calculation with clarification supporting each equation recommended for use by the guideline, arc welding EMI suppression guidance, adjustable and variable frequency speed drives EMI suppression guidance, lighting system EMI suppression guidance, wireless emissions control guidance, a summary of lessons learned and operating experience from nuclear industry related EMI events.
The Errata version corrects an issue in the heading row for Table K-1, the column labels for Low-Frequency and High-Frequency under Emission Test for Radiated were transposed. |
| Revision 4 | 2020 (Errata)
2013 |
This revision of the EPRI guidance made better use than previous ones of EMC testing standards commonly used by equipment vendors and suppliers and generally reduced differences with the recommendations of NRC Regulatory Guide 1.180, Revision 1. Where differences remained, the bases for the Revision 4 position were provided. One issue of special note in Revision 4 is its treatment of CS114. The CS114 test levels recommended in previous revisions of this report and in Regulatory Guide 1.180, Revision 1, were based on plant data acquired by EPRI in the early 1990s. The latest results indicate that the early data was misapplied, and less conservative test levels were recommended.
The Errata version corrects a discrepancy on the RS103 test frequency range appearing in Chapter 5 and on MIL-STD-461G and the one appearing in Appendix K. |
| Revision 3 | 2004 | Not available on EPRI website, revision 3 incorporated the results of the 2003 reevaluation of the conducted susceptibility limits and proposed less conservative test levels. |
| Revision 2 | 2000 | This version revised the limits to reduce excessive conservatism, based on plant operating experience since the first version of the guide was released and broader frequency ranges to accommodate newer telecommunication devices. |
| Revision 1 | 1997 | Conditional on incorporation of a number of clarifications and publication of a revised report, the NRC issued a Safety Evaluation Report in April 1996 endorsing the revised report (the future revision 1). Since revision 1 was published, the TR-102323 became a de facto standard within the U.S. nuclear industry.
NOTE: The SER report has been maintained in the appendixes of the subsequent revisions of this guidance. |
| Revision 0 | 1994 | Not available on EPRI website, this first issue and was submitted to the NRC for revision. |
Electromagnetic Compatibility Assessment Methodology (EMCAM)[edit]
While TR-102323 supports a graded approach based on safety classification, it does not consider risk associated with different system use cases and applications. This is the intent of the Electromagnetic Compatibility Assessment Methodology (EMCAM). It provides risk-informed guidance for equipment EMC qualification and control method allocation. EMCAM is an alternate approach for assessing electromagnetic compatibility for a facility change and is not intended to replace the TR-102323 methodology. The two methods are compatible, and EMCAM does not invalidate any legacy equipment EMC qualification testing results. EMCAM is intended to complement the EPRI Digital Engineering Guide (DEG) in the conceptual or detailed design phase of an I&C project. The methodology evaluates EMC testing performance and control method allocation in new or modified I&C equipment designs using facility risk (e.g., impact to CDF) and application (e.g., installation environment classification) insights. Using the process requires either:
- a HAZCADS Risk Reduction Target (RRT) value and Control Effectiveness Profile (CEP) score from EPRI Hazard Analysis Methods for Digital Instrumentation and Control Systems or
- a user-defined qualitative risk tolerance that corresponds with the specific application or use of digital I&C equipment in a nuclear power facility.
Recommendations are made regarding the selection of electromagnetic susceptibility and emissions testing scope and level requirements to demonstrate reasonable confidence of EMC commensurate with risk, and provides flexibility to tailor the testing scope, testing level and further control method allocation based on a particular set of application requirements.
This process enables a user to decide which technical or administrative control methods to apply during system design and assessment to achieve a risk reduction target (RRT) value and Control Effectiveness Profile (CEP) score provided from a corresponding hazards analysis process, such as HAZCADS. EMCAM uses the CEP score value and equipment location information to identify recommended EMC testing parameters (acceptance criteria, scope and limits) and additional controls for nuclear facility I&C equipment modifications.
EMCAM versions access table[edit]
| Revision # | Publication year | Revision notes |
|---|---|---|
| Revision 0 | 2023 | The first issue of EPRI's risk-informed EMC assessment. |
Technology Assessments and Troubleshooting Methods and Results Reports[edit]
EPRI also developed the following EMC guidance to help guide technology implementation and use:
- A troubleshooting guide to help identify and correct EMI related malfunctions, and
- An analysis of radiated emission levels from several intentional radio frequency emitters to help with determining appropriate controls supporting their usage inside a plant .
Troubleshooting EMI[edit]
The Electromagnetic Interference (EMI) Troubleshooting Guide assists practitioners with the development of a troubleshooting methodology that can be used by utility personnel to diagnose and resolve EMI issues. The report provides the necessary background and supporting information to develop an EMI troubleshooting guide that will help save time and money by making it easier to trace, diagnose and resolve EMI issues in the field. It may be used by utilities to directly implement its guidance at a facility or to aid in interactions with vendors by ensuring a common understanding and compliance with reputable electromagnetic compatibility standards and techniques.
Technology Assessment Reports[edit]
EPRI continues to assess new technologies introduced at the plants to identify EMI issues and propose control methods to ensure EMC compatibility. Available assessments are listed in the table below:
| Title | Publication year | Description |
|---|---|---|
| Wireless Technology Assessment: Analysis of Radiated Emissions from Common Phones, Laptops, and Tablets - 2024 Update | 2024 | This report provides an update to the guidance contained in the previous report to include a sampling of the latest cellular phones, tablet devices, and other devices using these additional wireless communications protocols. The information contained in it is intended to provide the nuclear industry with example data from wireless technology to support their own internal evaluations of the technology and the establishment of associated exclusion zones. |
| Li-Fi Wireless Communications: Technology Evaluation for Utility Applications | 2023 | This report includes discussions not only about radiated and electromagnetic emissions, but also examines the potential benefits and challenges of Li-Fi technologies related to security, spectrum output, and communication performance. |
| EPRI Robotics Research: Electromagnetic Compatibility Assessment of SPOT Robotic Platform | 2022 | Documents the completed electromagnetic compatibility testing of a Spot robot for radio frequency emissions, and susceptibility characterization in accordance with EPRI product 3002015757, Guidelines for Electromagnetic Compatibility Testing of Power Plant Equipment, Revision 5 to TR-102323. |
| Wireless Technology Assessment: Analysis of Radiated Emissions from Common Phones, Laptops, and Tablets | 2018 | Provides the bounding exclusion zones for three wireless protocols (Wi-Fi, Bluetooth, and LTE) and examines field strengths generated within the far-field of wireless transmission for a subset of wireless devices during normal operation. |
| Wireless Sensor Survey and General Specification | 2018 | This report presents the various wireless sensor technologies that are commercially available; an overview of EMI/RFI concerns for wireless sensor technology, including laboratory test results for numerous sensors; guidance for specifying and procuring wireless sensor technology to meet a particular equipment condition monitoring application; and the suggested responsibilities of various departments within the power plant during the implementation of wireless technology.
|
EMI Documented Experiences Analysis[edit]
EPRI has documented the analysis of EMI events to inform the industry of EMI risks and offer suggestion on how they can be further mitigated (see the table below). Additionally, Guidelines for Electromagnetic Compatibility Testing of Power Plant Equipment: Revision 5 to TR-102323 in its appendix L includes a summary of lessons learned and OE obtained from the 2011 report mentioned in the table and EMI events are presented in EPRI EMI Qualification of Digital Equipment Upgrades CBT mentioned in the Training Materials section above.
| Title | Publication year | Description |
|---|---|---|
| Assessment of Electromagnetic Interference Events in Nuclear Power Plants | 2011 | This report seeks to identify, collect, and analyze the EMI-related incidents in an effort to understand the level and trends in these events. Beyond trends, the analysis probes the causal factors of the events. The fundamental physics of the events is studied with the objective of using an improved understanding of the physics of interference for evaluating the range of mitigations that are possible. |
| Indian Point-2 Flash Photography Event | 2009 | This report presents the results of an independent assessment by the EPRI Electromagnetic & Radio Frequency Interference Working Group on a flash photography event at the Indian Point-2 (IP-2) nuclear power plant.
|
Record of Revisions[edit]
| Number | Date | Description of changes |
|---|---|---|
| 0 | August 2024 | Initial release |