ML22208A232

DG-1409 (RG 1.204 Rev. 1) Guidelines for Lightning Protection for Production and Utilization Facilities

ML22208A232
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Issue date:	04/30/2023
From:	Hardin L NRC/RES/DE/CIB
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Steckel J
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ML22112A182:ML22112A182	List: ML22208A232 ML22208A234 ML22208A241
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RG 1.240 Rev 1 DG-1409
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U.S. NUCLEAR REGULATORY COMMISSION DRAFT REGULATORY GUIDE (DG)-1409 Proposed Revision 1 to Regulatory Guide 1.204 Issue Date: April 2023 Technical Lead: Roy Hardin GUIDELINES FOR LIGHTNING PROTECTION FOR PRODUCTION AND UTILIZATION FACILITIES A. INTRODUCTION Purpose This regulatory guide (RG) endorses, with clarifications, the methods described in the Institute of Electrical and Electronics Engineers (IEEE) Standard (Std.) 665-1995, IEEE Standard for Generating Station Grounding (Ref. 1); IEEE Std. 666-2007, IEEE Design Guide for Electrical Power Service Systems for Generating Stations, (Ref. 2); IEEE Std. 1050-2004, IEEE Guide for Instrumentation and Control Equipment Grounding in Generating Stations, (Ref. 3); and IEEE Std. C62.23-2017, IEEE Application Guide for Surge Protection of Electric Generating Plants, (Ref. 4) as an acceptable process for demonstrating compliance with the applicable U.S. Nuclear Regulatory Commission (NRC) regulations for adequate lightning protection of safety-related systems, structures, and components (SSCs) in production and utilization facilities.

Applicability This RG applies to licensees and applicants subject to Title 10 of the Code of Federal Regulations (10 CFR), Part 50, Domestic Licensing of Production and Utilization Facilities (Ref. 7) and 10 CFR Part 52, Licenses, Certifications, and Approvals for Nuclear Power Plants (Ref. 8). With respect to 10 CFR Part 50, this RG applies to holders of or an applicant for an operating license. With respect to 10 CFR Part 52, this RG applies to applicants and holders of combined licenses, standard design certifications, standard design approvals, and manufacturing licenses. This RG does not apply to production and utilization facilities that have submitted certifications as required by 10 CFR 50.82(a)(1) and by 52.110(a).

Applicable Regulations

• 10 CFR Part 50 o 10 CFR 50.49(d) requires an applicant or licensee to prepare a list of electric equipment important to safety as listed in 50.49(b) and to include information for this electric equipment on performance specifications under conditions existing during and following design basis accidents; the voltage, frequency, load, and other electrical characteristics for which these This RG is being issued in draft form to involve the public in the development of regulatory guidance in this area. It has not received final staff review or approval and does not represent an NRC final staff position. Public comments are being solicited on this DG and its associated regulatory analysis. Comments should be accompanied by appropriate supporting data. Comments may be submitted through the Federal rulemaking Web site, http://www.regulations.gov, by searching for draft regulatory guide DG-1409 Alternatively, comments may be submitted to the Office of Administration, Mailstop: TWFN 7A-06M, U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001, ATTN: Program Management, Announcements and Editing Staff. Comments must be submitted by the date indicated in the Federal Register notice.

Electronic copies of this DG, previous versions of DGs, and other recently issued guides are available through the NRCs public Web site under the Regulatory Guides document collection of the NRC Library at https://nrcweb.nrc.gov/reading-rm/doc-collections/reg-guides/. The DG is also available through the NRCs Agencywide Documents Access and Management System (ADAMS) at http://www.nrc.gov/reading-rm/adams.html, under Accession No. ML22208A232. The regulatory analysis may be found in ADAMS under Accession No. ML22208A234.

performance specifications can be ensured; and the environmental conditions, including temperature, pressure, humidity, radiation, chemicals, and submergence at the location where the equipment must perform as specified.

o 10 CFR 50.49(b) defines electric equipment important to safety as safety-related electric equipment (Class 1E equipment in IEEE 323-1974) that is relied upon to remain functional during and following design basis events to ensure the integrity of the reactor coolant pressure boundary; the capability to shut down the reactor and maintain it in a safe shutdown condition; or the capability to prevent or mitigate the consequences of accidents that could result in potential offsite exposures.

o 10 CFR Part 50, Appendix A, GDC 2, Design Bases for Protection against Natural Phenomena, requires, in part, that SSCs important to safety be designed to withstand the effects of natural phenomena without loss of capability to perform their safety functions. The design bases for these SSCs must reflect (1) appropriate consideration of the most severe natural phenomena that have been historically reported for the site and surrounding area, with sufficient margin for limited accuracy, quantity, and period of time in which the historical data have been accumulated; (2) appropriate combinations of the effects of normal and accident conditions with the effects of the natural phenomena; and (3) the importance of the safety functions to be performed.

• 10 CFR Part 52 o 10 CFR 52.47(a)(13) requires that an applicant for a design certification must provide the list of electrical equipment important to safety as specified in 10 CFR 50.49(d).

o 10 CFR 52.137(a)(13) requires that an applicant for a standard design approval must provide the list of electric equipment that is important to safety as defined by 10 CFR 50.49(d).

Related Guidance

• RG 1.180, Guidelines for Evaluating Electromagnetic and Radio-Frequency Interference in Safety-Related Instrumentation and Control Systems, (Ref. 9) which describes methods and procedures considered acceptable for demonstrating compliance with the NRCs regulations on design, installation, and testing to address the effects of electromagnetic and radiofrequency interference (EMI/RFI), power surges, and electrostatic discharge on safety-related instrumentation and control systems.

• NUREG-1537, Parts 1 and 2, Guidelines for Preparing and Reviewing Applications for the Licensing of Non-Power Reactors, issued February 1996 (Ref. 10), contains format and content guidance for non-power reactor applicants and licensees, as well as a standard review plan and acceptance criteria for NRC staff.

• Final Interim Staff Guidance Implementing NUREG-1537, Parts 1 and 2, for Licensing Radioisotope Production Facilities and Aqueous Homogeneous Reactors, issued October 2012 (Ref. 11), contains format and content guidance for non-power aqueous homogeneous reactor and radioisotope production facility applicants and licensees, as well as a standard review plan and acceptance criteria for NRC staff.

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• Endorsement of Appendix A to Oak Ridge National Laboratory Report, Proposed Guidance For Preparing and Reviewing A Molten Salt Non-Power Reactor Application, as Guidance for Preparing Applications for the Licensing of Non-Power Liquid Fueled Molten Salt Reactors, dated November 18, 2020, (Ref. 12) which endorses with clarifications, Proposed Guidance for Preparing and Reviewing a Molten Salt Non-Power Reactor Application (ORNL/TM-2020/1478) to support the review of non-power molten salt reactors (Ref. 13).

Purpose of Regulatory Guides The NRC issues RGs to describe methods that are acceptable to the staff for implementing specific parts of the agencys regulations, to explain techniques that the staff uses in evaluating specific issues or postulated events, and to describe information that the staff needs in its review of applications for permits and licenses. Regulatory guides are not NRC regulations and compliance with them is not required.

Methods and solutions that differ from those set forth in RGs are acceptable if supported by a basis for the issuance or continuance of a permit or license by the Commission.

Paperwork Reduction Act This RG provides voluntary guidance for implementing the mandatory information collections in 10 CFR Parts 50 and 52 that are subject to the Paperwork Reduction Act of 1995 (44 U.S.C. 3501 et.

seq.). These information collections were approved by the Office of Management and Budget (OMB),

approval numbers 3150-0011 and 3150-0151. Send comments regarding this information collection to the FOIA, Library, and Information Collections Branch (T6-A10M), U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001, or by e-mail to Infocollects.Resource@nrc.gov and to the OMB reviewer at: OMB Office of Information and Regulatory Affairs (3150-0011 and 3150-0151), Attn: Desk Officer for the Nuclear Regulatory Commission, 725 17th Street, NW Washington, DC20503; e- mail:

oira_submission@omb.eop.gov.

Public Protection Notification The NRC may not conduct or sponsor, and a person is not required to respond to, a collection of information unless the document requesting or requiring the collection displays a currently valid OMB control number.

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B. DISCUSSION Reason for Revision Revision 0 of RG 1.204 was issued in November 2005 to endorse IEEE Std. 665-1995 (Ref. 1);

IEEE Std. 666-1991 (Ref. 14); IEEE Std. 1050-1996 (Ref. 15); and IEEE Std. C62.23-1995 (Ref. 16).

The IEEE standards 1050, 666 and C62.23 were revised in 2004, 2007 and 2017, respectively. This revision updates the RG to endorse IEEE Std. 665-1995; IEEE Std. 1050-2004; IEEE Std. 666-2007; and IEEE Std. C62.23-2017, with certain clarifications.

Background

Experience shows that lightning can pose operational threats to production and utilization facilities. Therefore, protection is essential to avoid malfunctions and upsets that, in turn, can lead to reactor trips. Nuclear power plants and other facilities should have a well-designed and properly installed lightning protection system (LPS) to safeguard their SSCs from lightning strikes and the resulting secondary effects. To protect against the effects of lightning strikes, the LPS should incorporate strike termination devices, discharge down conductors, and a grounding system. To protect against the secondary effects of lightning strikes, such as potentially disruptive surges and EMI/RFI that can propagate to internal structures and cause damage to safety-related systems, the LPS should also incorporate appropriate individual equipment grounding systems and surge protection devices (SPDs).

The NRC staff has reviewed IEEE Std. 665-1995, IEEE Std. 666-2007, IEEE Std. 1050-2004, and IEEE Std. C62.23-2017 and determined that they are acceptable standards for lightning protection for production and utilization facilities.

IEEE Std. 665-1995 (reaffirmed 2001) describes facility grounding practices and serves as the primary source of guidance on lightning protection for structures at power generating stations. As such, this standard identifies the grounding practices that the electric utility industry has generally accepted as contributing to effective grounding systems for personnel safety and equipment protection in generating stations. This standard also provides guidance for the design of generating station grounding systems and grounding practices applied to generating station indoor and outdoor structures and equipment.

IEEE Std. 666-2007 describes grounding practices for neutral grounding and grounding methods for medium-voltage equipment. As such, this standard is a design guide intended for application to generating station service systems that supply electric power to auxiliary equipment. This design guide applies to all types of generating stations that produce electric power and is particularly applicable to stations in which the electric power service is required to perform continuously. Such a service system consists of a main auxiliary power distribution network that might supply many subsystems (including direct current systems and Class 1E power systems), much of which is medium-voltage (2.4-13.8 kV) equipment.

This standard addresses recommendations for neutral grounding, as well as the grounding of generating station auxiliaries. It also covers grounding methods for both low-voltage (120-480 V) and medium-voltage power service systems. The low-voltage grounding methods parallel similar guidance in IEEE Std. 665. In addition, this standard covers surge protection of transformers, switchgear, and motors, paralleling similar guidance in IEEE Std. C62.23.

IEEE Std. 1050-2004 describes design and installation practices regarding grounding methods for I&C equipment. As such, this standard recommends grounding methods for I&C equipment to achieve a DG-1409, Page 4

suitable level of protection for personnel and equipment, as well as suitable noise immunity for signal-ground references in generating stations. IEEE Std. 1050-2004 is comprehensive, in that it covers both theoretical and practical aspects of grounding and noise minimization.

Surge protection measures are vital for protection of the power plant, ancillary facilities that could impact safety, the switchyard, the electrical distribution system, safety-related I&C systems, and communication systems from both direct lightning strikes and the resulting power surges. SPDs should be applied at the entry and egress points for signal-, communication-, and power-line conductors. They should also be applied to any equipment that is thought to be vulnerable to high-energy surges. The selection of SPDs typically depends on the location of the devices and the size(s) needed to prevent the energy from a lightning strike from impinging a facility or piece of equipment.

IEEE Std. C62.23-2017 describes surge protection application practices applicable to power generating stations. As such, this standard consolidates many electric utility industry practices, accepted theories, existing standards/guides, definitions, and technical references as they specifically pertain to surge protection. This standard also provides information on proper surge protection techniques and interference reduction practices for communication, control, and protection circuits. The standard covers the protection of transmission lines and switchyard equipment from direct lightning strikes (using overhead ground wires, tower footing resistance, counterpoise wires, and surge arresters on transmission lines); protection of distribution lines from direct lightning strikes, switching surges, and ferroresonance; and the selection of arrestors for distribution lines. The standard covers the protection of both indoor and outdoor equipment (including transformers, motors, switchgear, etc.) from direct lightning strikes, incoming surges, internally generated surges, and ground potential rises. It also covers the protection of control and communication circuits and discusses the beneficial effects of shielding, grounding, and cable routing in the power plant buildings. In addition, the standard covers the protection of remote ancillary facilities, dealing primarily with protection from direct lighting strikes and the surges induced on underground cables.

IEEE Std. 665-1995, IEEE Std. 666-2007, IEEE Std. 1050-2004, and IEEE Std. C62.23-2017 reference other IEEE standards that contain useful information but are not endorsed in this RG; these secondary references are listed in Appendix A for clarity. Two other useful secondary references are National Fire Protection Association (NFPA) Standard 780, Standard for the Installation of Lightning Protection Systems," (Ref. 5) and Underwriters Laboratories (UL) Standard 96A, Installation Requirements for Lightning Protection Systems, (Ref. 6). While the NRC staff is not endorsing these two standards due to their exclusion of electric power generation facilities, staff notes that Annex B Principles of Lightning Protection and Annex D Inspection and Maintenance of Lightning Protection Systems in NFPA 780 provide useful information on testing and maintenance practices that licensees and applicants may wish to reference in developing their own testing and maintenance practices.

Consideration of International Standards The International Atomic Energy Agency (IAEA) works with member states and other partners to promote the safe, secure, and peaceful use of nuclear technologies. The IAEA develops Safety Requirements and Safety Guides for protecting people and the environment from harmful effects of ionizing radiation. This system of safety fundamentals, safety requirements, safety guides, and other relevant reports, reflects an international perspective on what constitutes a high level of safety. To inform its development of this RG, the NRC considered IAEA Safety Requirements and Safety Guides pursuant to the Commissions International Policy Statement (Ref. 17) and Management Directive and Handbook 6.6, Regulatory Guides (Ref. 18).

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IAEA Specific Safety Guide No. SSG-34, Design of Electrical Power Systems for Nuclear Power Plants, issued March 2016 (Ref. 19), which provides guidance for lightning protection of internal and external systems and components important for safe plant operation, was considered in the development of this RG.

Documents Discussed in Staff Regulatory Guidance This RG endorses, in part, the use of one or more codes or standards developed by external organizations, and other third-party guidance documents. These codes, standards, and third-party guidance documents may contain references to other codes, standards, or third-party guidance documents (secondary references). If a secondary reference has itself been incorporated by reference into NRC regulations as a requirement, then licensees and applicants must comply with that standard as set forth in the regulation. If the secondary reference has been endorsed in a RG as an acceptable approach for meeting an NRC requirement, then the standard constitutes a method acceptable to the NRC staff for meeting that regulatory requirement as described in the specific RG. If the secondary reference has neither been incorporated by reference into NRC regulations nor endorsed in a RG, then the secondary reference is neither a legally-binding requirement nor a generic NRC-approved acceptable approach for meeting an NRC requirement. However, licensees and applicants may consider and use the information in the secondary reference, if appropriately justified, consistent with current regulatory practice, and consistent with applicable NRC requirements.

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C. STAFF REGULATORY GUIDANCE The collective guidance in IEEE Std. 665-19951; IEEE Std. 666-2007; IEEE Std.1050-2004; IEEE C62.23-2017 provide an acceptable approach to the NRC staff for meeting the agencys regulatory requirements for adequate lightning protection of SSCs in production and utilization facilities with the clarifications below.

1. LPSs should be inspected following installation, and systems should be inspected on a regular, periodic basis throughout their lifetime. LPS systems should be inspected whenever any alterations or repairs are made to a protected structure, as well as following any known lightning transient to the system. An LPS should be visually inspected at least annually. In areas where severe climatic changes occur, it is advisable to inspect the LPS semiannually or following extreme changes in ambient temperature. An in-depth inspection of the LPS every 3-5 years to assess the effects of aging is also recommended.

2. Testing and maintenance procedures should be established for each LPS. The frequency of testing and maintenance will depend on weather-related degradation of protective features, frequency and severity of damage attributable to lightning transients, and required protection level. Also, an LPS testing and maintenance program should include (1) inspection of all conductors and system components, (2) tightening of all clamps and splicers, (3) measurement of the earth grounding resistance, (4) measurement of the resistance of ground terminals, (5) inspection or testing (or both) of SPDs to assess their effectiveness, (6) periodic testing and maintenance of earth grounding systems, (7) refastening and tightening of components and conductors as required, (8) inspection and testing when the LPS has been altered by additions to, or changes in, the structure, and (9) complete records.

1 IEEE Std. 665-1995 Section 5.7.4 should reference IEEE Std. 142-1991 Subclause 4.2.3 rather than IEEE Std. 142-1991 Subclause 4.2.4.

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D. IMPLEMENTATION The NRC staff may use this RG as a reference in its regulatory processes, such as licensing, inspection, or enforcement. However, the NRC staff does not intend to use the guidance in this RG to support NRC staff actions in a manner that would constitute backfitting as that term is defined in 10 CFR 50.109, Backfitting, and as described in NRC Management Directive 8.4, Management of Backfitting, Forward Fitting, Issue Finality, and Information Requests, (Ref. 20), nor does the NRC staff intend to use the guidance to affect the issue finality of an approval under 10 CFR Part 52, Licenses, Certifications, and Approvals for Nuclear Power Plants. The staff also does not intend to use the guidance to support NRC staff actions in a manner that constitutes forward fitting as that term is defined and described in Management Directive 8.4. If a licensee believes that the NRC is using this RG in a manner inconsistent with the discussion in this Implementation section, then the licensee may file a backfitting or forward fitting appeal with the NRC in accordance with the process in Management Directive 8.4.

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REFERENCES 2

1. Institute of Electrical and Electronics Engineers (IEEE) Standard (Std.) 665-1995, IEEE Standard for Generating Station Grounding, Piscataway, NJ.3

2. IEEE Std. 666-2007, IEEE Design Guide for Electrical Power Systems for Generating Stations, Piscataway, NJ.

3. IEEE Std. 1050-2004, IEEE Guide for Instrumentation and Control Equipment Grounding in Generating Stations, Piscataway, NJ.

4. IEEE Std. C62.23-2017, IEEE Application Guide for Surge Protection of Electric Generating Plants, Piscataway, NJ.

5. National Fire Protection Association (NFPA) Standard 780-2020, Standard for the Installation of Lightning Protection Systems," Washington, DC.4

6. Underwriters Laboratories (UL) Standard 96A-2016, Installation Requirements for Lightning Protection Systems, Northbrook, IL.5

7. CFR, Domestic Licensing of Production and Utilization Facilities, Part 50, Chapter 1, Title 10, Energy.

8. CFR, Licenses, Certifications, and Approvals for Nuclear Power Plants, Part 52, Chapter 1, Title 10, Energy.

9. U. S. Nuclear Regulatory Commission (NRC) Regulatory Guide 1.180, Guidelines for Evaluating Electromagnetic and Radio-Frequency Interference in Safety-Related Instrumentation and Control Systems, Revision 2, December 2019, Washington, DC (ML19175A014)

10. NRC, NUREG-1537, Guidelines for Preparing and Reviewing Applications for the Licensing of Non-Power Reactors, Washington, DC, February 1996.

11. NRC, Interim Staff Guidance Implementing NUREG-1537, Guidelines for Preparing and Reviewing Applications for the Licensing of Non-Power Reactors, Part 1 and Part 2, Washington, DC, October 2012.

12. Endorsement of Appendix A to Oak Ridge National Laboratory Report, Proposed Guidance for Preparing and Reviewing a Molten Salt Non-Power Reactor Application, as Guidance for 2 Publicly available NRC published documents are available electronically through the NRC Library on the NRCs public Web site at http://www.nrc.gov/reading-rm/doc-collections/ and through the NRCs Agencywide Documents Access and Management System (ADAMS) at http://www.nrc.gov/reading-rm/adams.html The documents can also be viewed online or printed for a fee in the NRCs Public Document Room (PDR) at 11555 Rockville Pike, Rockville, MD. For problems with ADAMS, contact the PDR staff at 301-415-4737 or (800) 397-4209; fax (301) 415-3548; or e-mail pdr.resource@nrc.gov.

3 IEEE publications may be purchased from the IEEE Service Center, which is located at 445 Hoes Lane, Piscataway, NJ 08855.

4 NFPA documents may be purchased from the NFPA Contact Center, which is located at 11 Tracy Drive, Avon, MA 02322.

5 UL documents may be purchased from the Comm 2000, which is located at 151 Eastern Avenue, Bensenville, IL 60106.

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Preparing Applications for the Licensing of Non-Power Liquid Fueled Molten Salt Reactors, dated November 18, 2020. (ML20251A008)

13. Oak Ridge National Laboratory, Proposed Guidance for Preparing and Reviewing a Molten Salt Non-Power Reactor Application, (ORNL/TM-2020/1478). (ML20219A771)

14. IEEE Std. 666-1991, IEEE Design Guide for Electrical Power Systems for Generating Stations, Piscataway, NJ.

15. IEEE Std. 1050-1996, IEEE Guide for Instrumentation and Control Equipment Grounding in Generating Stations, Piscataway, NJ.

16. IEEE Std. C62.23-1995, IEEE Application Guide for Surge Protection of Electric Generating Plants, Piscataway, NJ.

17. NRC, Nuclear Regulatory Commission International Policy Statement, Federal Register, Vol.

79, No. 132, July 10, 2014, pp. 39415-39418.

18. NRC, Management Directive (MD) 6.6, Regulatory Guides, Washington, DC.

19. IAEA Specific Safety Guide no. SSG-34, Design of Electrical Power Systems for Nuclear Power Plant, March 2016. 6

20. NRC, Management of Backfitting, Forward Fitting, Issue Finality, and Information Requests, Management Directive 8.4.

6 Copies of International Atomic Energy Agency (IAEA) documents may be obtained through their Web site:

WWW.IAEA.Org/ or by writing the International Atomic Energy Agency, P.O. Box 100 Wagramer Strasse 5, A-1400 Vienna, Austria.

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SECONDARY REFERENCES IN ENDORSED DOCUMENTS STANDARD NUMBER STANDARD TITLE IEEE Std. 80-2013 IEEE Guide for Safety in AC Substation Grounding (ANSI)

IEEE Guide for Measuring Earth Resistivity, Ground Impedance, IEEE Std. 81-2012 and Earth Surface Potentials of a Ground System (ANSI)

IEEE Guide for Measurement of Impedance and Safety IEEE Std. 81.2-1991 Characteristics of Large, Extended or Interconnected Grounding Systems IEEE Recommended Practice for Grounding of Industrial and IEEE Std. 142-2007 Commercial Power Systems (IEEE Green Book)

IEEE Recommended Practice for Determining the Electric Power IEEE Std. 367-2012 Station Ground Potential Rise and Induced Voltage from a Power Fault (ANSI)

IEEE Recommended Practice for the Protection of Wire-Line IEEE Std. 487-2015 Communication Facilities Serving Electric Supply Locations (ANSI)

IEEE Recommended Practice for Powering and Grounding IEEE Std. 1100-2005 Electronic Equipment (IEEE Emerald Book) (ANSI)

IEEE Std. C37.101-2006 IEEE Guide for Generator Ground Protection (ANSI)

IEEE Guide for the Grounding of Instrument Transformer IEEE Std. C57.13.3-2014 Secondary Circuits and Cases (ANSI)

IEEE Guide for the Application of Neutral Grounding in Electrical IEEE Std. C62.92.1-2016 Utility Systems, Part I-Introduction (ANSI)

IEEE Guide for the Application of Neutral Grounding in Electrical IEEE Std. C62.92.2-2017 Utility Systems, Part II-Grounding of Synchronous Generator Systems (ANSI)

IEEE Guide for the Application of Neutral Grounding in Electrical IEEE Std. C62.92.3-2012 Utility Systems, Part III-Generator Auxiliary Systems (ANSI)

IEEE Guide on the Surge Environment in Low-Voltage (1000 V IEEE Std. C62.41.1-2002 and Less) AC Power Circuits (ANSI)

IEEE Recommended Practice on Characterization of Surges in IEEE Std. C62.41.2-2002 Low-Voltage (1000 V and Less) AC Power Circuits (ANSI)

IEEE Recommended Practice on Surge Testing for Equipment IEEE Std. C62.45-2002 Connected to Low-Voltage (1000 V and Less) AC Power Circuits (ANSI)

DG-1409, Appendix A, Page A-1