ML071440445

DG-1132 Qualification of Safety-Related Cables and Field Splices for Npps.

ML071440445
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Issue date:	06/30/2007
From:	Aggarwal S Office of Nuclear Regulatory Research
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Aggarwal S 415-6005
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DG-1132
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This regulatory guide is being issued in draft form to involve the public in the early stages of the development of a regulatory position in this area. It has not receivedfinal staff review or approval and does not represent an official NRC staff position.Public comments are being solicited on this draft guide (including any implementation schedule) and its associated regulatory analysis or value/impact statement. Comments should be accompanied by appropriate supporting data. Written comments may be submitted to the Rulemaking, Directives, and Editing Branch, Office ofAdministration, U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001; emailed to NRCREP@nrc.gov; submitted through the NRC's interactiverulemaking Web page at http://www.nrc.gov

faxed to (301) 415-5144; or hand-delivered to Rulemaking, Directives, and Editing Branch, Office of Administration, USNRC, 11555 Rockville Pike, Rockville, Maryland 20852. Between 7

30 a.m. and 4:15 p.m. on Federal workdays. Copies of comments received may be examined atthe NRC's Public Document Room, 11555 Rockville Pike, Rockville, MD. Comments will be most helpful if received by 60 days from issuance

.Requests for single copies of draft or active regulatory guides (which may be reproduced) or for placement on an automatic distribution list for single copies of futuredraft guides in specific divisions should be made to the U.S. Nuclear Regulatory Commission, Washington, DC 20555, Attention: Reproduction and DistributionServices Section, or by fax to (301)415-2289; or by email to Distribution@nrc.gov. Electronic copies of this draft regulatory guide are available through the NRC'sinteractive rulemaking Web page (see above); the NRC's public Web site under Draft Regulatory Guides in the Regulatory Guides document collection of the NRC'sElectronic Reading Room at http://www.nrc.gov/reading-rm/doc-collections/; and the NRC's Agencywide Documents Access and Management System (ADAMS) athttp://www.nrc.gov/reading-rm/adams.html, under Accession No. ML071440445.U.S. NUCLEAR REGULATORY COMMISSION June 2007OFFICE OF NUCLEAR REGULATORY RESEARCH Division 1 DRAFT REGULATORY GUIDEContact: Satish Aggarwal (301) 415-6005DRAFT REGULATORY GUIDE DG-1132QUALIFICATION OF SAFETY-RELATED CABLESAND FIELD SPLICES FOR NUCLEAR POWER PLANTSA. INTRODUCTIONThe regulations established by the U.S. Nuclear Regulatory Commission (NRC) in Title 10, Part 50, of the Code of Federal Regulations (10 CFR Part 50), "Domestic Licensing of Production andUtilization Facilities," require that structures, systems, and components that are important to safety in anuclear power plant must be designed to accommodate the effects of environmental conditions [i.e.,remain functional under postulated design-basis events (DBEs)]. Toward that end, the generalrequirements are contained in General Design Crite ria 1, 2, 4, and 23 of Appendix A, "General Design Criteria for Nuclear Power Plants," to 10 CFR Part 50. Augmenting those general requirements, thespecific requirements pertaining to qualification of certain electrical equipment important to safety arecontained in 10 CFR 50.49, "Environmenta l Qualification of Electric Equipment Important to Safety for Nuclear Power Plants." In addition, Criterion III, "Design Control," of Appendix B, "Quality Assurance Criteria for Nuclear Power Plants,"

to 10 CFR Part 50, requires that where a test program is used toverify the adequacy of a specific design feature, it must include suitable qualification testing of aprototype unit under the most severe DBE.This regulatory guide describes a method that the staff of the NRC considers acceptable forcomplying with the Commission's regulations for qualification of safety-related cables and field splices for nuclear power plants.The NRC issues regulatory guides to describe to the public methods that the staff considersacceptable for use in implementing specific parts of the agency's regulations, to explain techniques thatthe staff uses in evaluating specific problems or postulated accidents, and to provide guidance toapplicants. Regulatory guides are not substitutes for regulations, and compliance with regulatory guides is not required.

DG-1132, Page 2This regulatory guide contains information collections that are covered by the requirements of 10 CFR Part 50, and that the Office of Management and Budget (OMB) approved under OMB controlnumber 3150-0011. The NRC may neither conduct nor spons or, and a person is not required to respond to,an information collection request or requirement unless the requesting document displays a currently validOMB control number.B. DISCUSSIONIEEE Std 383-2003, "IEEE Standard for Qualifying Class 1E Electric Cables and Field Splices forNuclear Power Generating Stations," published on June 10, 2004 (Ref.1), was developed by the WorkingGroup on Cables (SC 2.4) of the Nuclear Power Engineering Committee of the Institute of Electrical andElectronics Engineers (IEEE) and was approved by the IEEE-SA Standards Board on December 12, 2003. That standard provides general requirements, direction, and methods for qualifying safety-related cables,field splices, factory splices, and factory rework for service in nuclear power plants. Categories of cablescovered are those used for power, control, and instrumentation services, including signal andcommunication cables. Most importantly, IEEE Std 383-2003 requires that the safety-related cables and field splices must meet or exceed specified performance requirements throughout their installed life and besubjected to quality assurance programs that include, but are not limited to, design, qualification, andproduction quality control.The objectives of qualification are to ensure that safety-related cables (single, multiconductor, andmultiplex, as well as coaxial, triaxial, and twinaxial) and field splices can be demonstrated to perform theirsafety functions under postulated DBEs, and that no failure mechanism exists that could lead to common-cause failures under postulated service conditions. It is the degradation over time, followed by exposure to the environmental extremes of temperature, pressure, humidity, radiation, mechanical stress, or chemicalspray (or a combination thereof) resulting from DBEs, which presents a potential for common-causefailures of safety-related cables and field splices. As a result, it is necessary to establish a qualified life forcables and splices that are installed in harsh environments and must perform a safety function during andfollowing the DBEs.These objectives should be accomplished using qualification methods (type testing, operatingexperience, analysis as a supplement to type testing and operating experience, ongoing qualification, orany combination thereof). However, qualification by analysis alone is not acceptable. Type testing ofsample cables or field splices is the preferred qualification method. In addition, IEEE Std 383-2003requires documentation, in an auditable form, to demonstrate that cables and field splices wouldadequately perform their safety functions.Power cables that are routed underground should be capable of performing their function whensubjected to anticipated environmental conditions such as moisture or flooding. Also, based on recentunderground power cable failures, the staff has concluded that the field splices for medium-voltage cablesin inaccessible locations should not be permitted. In addition, power and instrumentation and controlcables for which failures could disable risk-significant equipment should have condition monitoringprograms to demonstrate that the cables can perform their safety function when needed.C. REGULATORY POSITIONConformance with the requirements of IEEE Std 383-2003, "IEEE Standard for Qualifying Class 1E Electric Cables a nd Field Splices for Nuclear Power Generating Stations," is a method that the DG-1132, Page 3NRC staff considers acceptable for use in satisfying the Commission's regulations with respect toqualification of safety-related cables and field splices, subject to the following exceptions:(1)Clause 3.3, "Representative Cable," of IEEE Std 383-2003 should be supplemented with adescription of conductor type (material, strand, and strand type) and also differentiate betweenconductor shield, insulation shield, and overall static shield.(2)Clause 4, "Principle qualification criteria," should be supplemented as follows:(a)The documentation should include the cable or field splice's specification and qualification plan.(b)The documentation should include manufacturer's inspection and maintenancerequirements to maintain and demonstrate continued qualification throughout its qualified life.(c)A condition monitoring program should also be implemented.(3)Clause 6.1.2, "Coaxial, triaxial, and twinaxial," should also include specimens of identicalmaterials and construction, and the configuration should include connections.(4)Clause 6.2.1.1, "Conductor," should include the stranding configuration.(5)Clause 6.2.1.4, "Shielding," should include percent overlap and lay for tape shields.(6)Clause 6.2.2.6, "Identification," should include the date of applicable manufacturing standards andthe date of manufacture.(7)Clause 6.3, "Age conditioning," should be supplemented to include aged cable specimen and newsplice kits; and a new splice kit combining an aged cable with a new cable.(8)Clause 6.4.5, "Retained flexibility," should be supplemented to include the following:"The acceptance criteria for instrument cables should specify the minimum acceptable insulation resistance and signal attenuation limits."(9)Clause 9.1, "General," should be supplemented to include the following:"Identification of the applicable date of manufacturing standards used inspecification, manufacture, and selection of the factory acceptance criteriafor test specimens. Documentation should also include manufacturer'sinspection and maintenance requirements."(10)Power and instrumentation and control cables for which failures could disable risk-significantequipment should have condition monitoring programs to demonstrate that the cables can performtheir safety function when needed.IEEE Std 383-2003 references several industry codes and standards. If a referenced standard hasbeen separately incorporated into the regulations, licensees and applicants must comply with the standard as set forth in the regulations. By contrast, if the NRC staff has endorsed a referenced standard in aregulatory guide, that standard constitutes an acceptable method of meeting a regulatory requirement asdescribed in the regulatory guide.

DG-1132, Page 4 D. IMPLEMENTATIONThe purpose of this section is to provide information to applicants and licensees regarding theNRC staff's plans for using this draft regulatory guide. No backfit is intended or approved in connectionwith the issuance of this guide.The NRC has issued this draft guide to encourage public participation in its development. Exceptin cases in which an applicant or licensee proposes or has previously established an acceptable alternativemethod for complying with the specified portions of the regulations, the methods to be described in theactive guide will reflect public comments and will be used in evaluating (1) submittals in connection withapplications for construction permits, design certifications, operating licenses, and combined licenses, and(2) submittals from operating reactor licensees who voluntarily propose to initiate system modificationsinvolving cables and field splices.REGULATORY ANALYSIS1.BackgroundSince its issuance in February 1974, IEEE Std 383-1974, "Standard for Type Test of Class 1EElectric Cables, Field Spli ces, and Connections for Nuclear Power Generating Stations," has been used bythe nuclear industry for qualification of safety-related cables. At that time, the NRC staff had reservationsregarding IEEE Std 383-1974 and never endorsed its use. However, since that time, the staff has been working with IEEE in revising this standard, and a revised version, IEEE Std 383-2003, "Standard for Qualifying Class 1E Electric Cables and Field Splices for Nuclear Power Generating Stations," was issuedin June 2004. The significant changes to IEEE Std 383-1974 include (1) removing the vertical flame test procedure of IEEE Std 383-1974, (2) substituting a reference to IEEE Std. 1202-1991 (Ref. 2), and(3) removing the word "connections" from the title and scope of the standard because IEEE Std 572-1985(Ref. 3) is specific to the qualification of connections.2.ProblemSince its issuance in February 1974, nuclear power plant licensees have typically used IEEEStd 383-1974 for qualification of cables, subject to NRC staff review on a case-by-case basis. However, this has been inefficient.3.ObjectiveThe objective of this document is to provide clear guidance on qualification of safety-relatedcables and field splices. Issuing a regulatory guide is consistent with the NRC policy of evaluating thelatest versions of consensus safety standards in terms of their suitability for endorsement by regulatoryguides. This approach would also comply with the NRC's directive to use standards developed byconsensus bodies in accordance with Public Law 104-113, "National Technology and Transfer Act of

1995" (Ref. 4).4.Technical ApproachIEEE Std 383-1974 requires type testing as the only method of qualifying safety-related cables. By contrast, 10 CFR 50.49 allows alternative methods, such as qualification by past operating experience,analysis in combination with partial type test data, and so forth. These alternative qualification methods 1The IEEE standards are available for purchase from the IEEE Web site athttp://shop.ieee.org/ieeestore/Product.aspx?product_no=SS10041

.2The National Technology and Transfer Act of 1995 is available electronically through the Standards.gov Web siteadministered by the National Institute of Standards and Technology, http://standards.gov/standards_gov/index.cfm?do=documents.NTTAA

.DG-1132, Page 5are specifically included in IEEE Std 383-2003, and the vertical flame test procedure from IEEE Std 383-1974 has been removed.The purposes of IEEE Std 383-2003 are to provide improved guidance for cable and field splicequalification and to clarify the existing qualification principles. In addition, this revised standard addresses qualification of both field splices and factory-made sp lices, and includes the followingsignificant changes:*generic and specific qualification guidance*detailed discussion of qualification methods*specific test sample selection criteria

• treatment of jacketed single-conductor cables

• need for overall aging program for all critical cable components

• specific requirements for thermal and radiation exposure

• detailed guidance on documentation requirements

• specific reference to high-energy line break testing

• special guidance for coaxial, twinaxial, and triaxial cables (jacket integrity, voltage, andperformance testing)5.ConclusionThe NRC intends to issue this regulatory guide to enhance the licensing process. The staff hasconcluded that the proposed action will reduce unnecessary burden on both the NRC and its licensees, andwill result in an improved and more uniform process for qualifying safety-related cables and field splices. Moreover, the staff sees no adverse effects associated with issuing this regulatory guide.

REFERENCES1.IEEE Std. 383-2003, "IEEE Standard for Qualifying Class 1E Electric Cables and Field Splices forNuclear Power Generating Stations," Piscataway, NJ, 1994.

12.IEEE Std. 1202-1991, "IEEE Standard for Flame Testing of Cables for Use in Cable Tray inIndustrial and Commercial Occupancies," Institu te of Electrical and Electronics Engineers,Piscataway, NJ, 1991.3.IEEE Std 572-1985, "IEEE Standard for Qualification of Class 1E Connection Assemblies forNuclear Power Generating Stations," Institute of Electrical and Electronics Engineers, Piscataway,NJ, 1985.4.National Technology and Transfer Act of 1995 (Public Law 104-113), 104 th Congress of theUnited States of America, Washington, DC, March 7, 1996.

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