DG-1132

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DGDG--11321132

QUALIFICATION OF SAFETY-RELATED CABLES

AND FIELD SPLICES FORNUCLEAR POWER PLANTS

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Regulatory Guide 1.131Regulatory Guide 1.131

Describes a method acceptable to the NRCfor complying with regulations with regardto qualification testing of electric cables

and field splices.

Endorsed IEEE 383-1974

Only Draft So Not Issued

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RGRG--1.131 Key Items1.131 Key Items

Flame TestingFlame Testing Added Aged and Added Aged and UnagedUnaged TestingTesting

Defined Burner Test, Air and Gas InformationDefined Burner Test, Air and Gas Information

DBEDBE

Need to consider Plant Specific and MarginNeed to consider Plant Specific and Margin

Aging Aging – – 136C and 2 or More Points136C and 2 or More Points Ongoing QualificationOngoing Qualification

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DGDG--11321132

Draft Regulatory Guide 1.131Draft Regulatory Guide 1.131 Issued for Comments in June 2007Issued for Comments in June 2007

Comments September 2007Comments September 2007 At Least 4 Sets of Comments At Least 4 Sets of Comments

IEEEIEEE

NUGEQNUGEQ

WestinghouseWestinghouse

ExelonExelon

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DGDG--1132 Discussion1132 Discussion

Power cables that are routed undergroundshould be capable of performing their functionwhen subjected to anticipated environmental

conditions such as moisture or flooding. Also, based on recent underground power cable

failures, the staff has concluded that the field

splices for medium-voltage cables in inaccessiblelocations should not be permitted.

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Condition MonitoringCondition Monitoring

In addition, power and instrumentationand control cables for which failures coulddisable risk-significant equipment should

have condition monitoring programs todemonstrate that the cables can performtheir safety function when needed.

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ExceptionsExceptions

Endorses IEEE 383Endorses IEEE 383--2003 with 10 Exceptions2003 with 10 Exceptions (1) Clause 3.3, “Representative Cable,” of IEEE

Std 383-2003 should be supplemented with a

description of conductor type (material, strand,and strand type) and also differentiate betweenconductor shield, insulation shield, and overall

static shield.

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Condition Monitoring ProgramCondition Monitoring Program

(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 maintenance requirements to maintainand demonstrate continued qualification throughout

its qualified life. (c) A condition monitoring program should also be

implemented.

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ConnectionsConnections

(3) Clause 6.1.2, “Coaxial, triaxial, andtwinaxial,” should also include specimensof identical materials and construction,

and the configuration should includeconnections.

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Stranding ConfigurationStranding Configuration

(4) Clause 6.2.1.1, “Conductor,” shouldinclude the stranding configuration.

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ShieldingShielding

(5) Clause 6.2.1.4, “Shielding,” shouldinclude percent overlap and lay for tapeshields.

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IdentificationIdentification

(6) Clause 6.2.2.6, “Identification,” shouldinclude the date of applicablemanufacturing standards and the date of

manufacture.

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Age Conditioning Age Conditioning

(7) Clause 6.3, “Age conditioning,” shouldbe supplemented to include aged cablespecimen and new splice kits; and a new

splice kit combining an aged cable with anew cable.

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Retained FlexibilityRetained Flexibility

(8) Clause 6.4.5, “Retained flexibility,” should be supplemented to include thefollowing:

“The acceptance criteria for instrumentcables should specify the minimum

acceptable insulation resistance and signalattenuation limits.”

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GeneralGeneral

(9) Clause 9.1, “General,” should besupplemented to include the following:

“Identification of the applicable date of

manufacturing standards used in specification,manufacture, and selection of the factoryacceptance criteria for test specimens.

Documentation should also includemanufacturer’s inspection and maintenancerequirements.”

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(10) Power and instrumentation andcontrol cables for which failures coulddisable risk-significant equipment should

have condition monitoring programs todemonstrate that the cables can performtheir safety function when needed.

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IEEE NPEC CommentsIEEE NPEC Comments

Issued Via SCIssued Via SC--2 and NPEC2 and NPEC 6 Comments6 Comments


Representative CableRepresentative Cable

Principle Qualification Criteria

Connectors Age Conditioning

Retained Flexibility

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Condition MonitoringCondition Monitoring In addition, power and Instrumentation and control cables for which failures could

disable risk - significant equipment should have condition monitoring programs to

determine that the cables can perform their function when needed."

IEEE Comment: IEEE 383-2003 asserts that type testing is adequate to ensure thatcable and field splices will perform their intended functions during and after a designbasis event. The requirement to impose condition monitoring on a subset of Class I Eelectrical cables implies that qualification by type testing is no longer adequate. Thisis inconsistent with the qualification philosophy contained within IEEE 323-2003 andits daughter standards.

The requirement for CM is also being imposed without any condition monitoringtechniques being endorsed by IEEE 383-2003. The introduction of cable CMestablishes a requirement for testing with no defined test methodology or acceptancecriteria. The recommended use of such cable CM programs is also inconsistent withprior NRC conclusions regarding cable condition monitoring. The technical

assessment of Generic Safety Issue 168, determined that "typical I&C cablequalification test programs include numerous conservative practices that collectivelyprovide a high level of confidence that the installed I&C cables will perform theirintended functions during and following design-basis events, as required by Title 10,Section 50.49, (10 CFR 50.49), of the Code of Federal Regulations "EnvironmentalQualification of Electrical Equipment Important to Safety for Nuclear Power Plants".

IEEE Recommendation: The requirement for condition monitoring of Class 1E cables

should be omitted from the "Discussion", Regulatory Positions 2(c) and 10.

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Representative CableRepresentative Cable Clause 3.3, "Representative Cable," of IEEE Std 383-2003 should be

supplemented with a description of conductor type (material,

strand, and strand type) and also differentiate between conductorshield, insulation shield, and overall static shield.

IEEE Comment: The IEEE is not aware of any research,qualification test, or experience information suggesting thatconductor material, strand, and strand type can affect qualification

results of the cable's performance during DBE testing. Since thischange is being recommended to the definition of representativecable" this could lead to the interpretation that any change in theconductor material, strand, and strand type would have to bequalified. The requirement to Include additional test samples for achange that does not impact qualification is not warranted and will

add an unnecessary complexity to the qualification process. IEEE Recommendation: Delete regulatory position 1.

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Principle Qualification Criteria Clause 4, "Principal 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

maintenance requirements to maintain and demonstrate continuedqualification throughout its qualified life.

(c) a condition monitoring program should also be implemented. IEEE Comment: The information required with items (a) and (b) is

currently required. Clause 4 currently requires that thedocumentation used to demonstrate qualification includes:

- The cable or field splice's specification or qualification plan - Inspection and maintenance requirements - Summaries and conclusions See previous comments on cable condition monitoring. IEEE recommendation: Delete Regulatory Position 2.

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Connectors Clause 6.1.2, "Coaxial, triaxiel, and twinaxial," should also include specimens of

identical materials and construction, and configuration should include connections.

IEEE comments: Clause 6.1.2 currently requires that test specimens use identicalmaterials and unique construction features, including braid angle and shield fillermaterials. The test specimens must also meet the requirements of a "RepresentativeCable". To add identical constructions could be implied to mean that every coaxialcable (RG 6, 58, etc.) is tested. This will require test specimens for each and everycable variation offered by a manufacturer. Such a requirement is an unnecessaryburden, inhibits the use of minor cable design changes, and is inconsistent with the

qualification of other cable types. IEEE 383-2003 and current practice rely on testingof representative cables with identical materials and specific characteristics but do notrequire identical constructions. IEEE also disagrees that the coaxial, triaxial, andtwinaxial test specimens include connections. IEEE 383-2003 specifically removedconnections from its scope. Connectors are now addressed in IEEE Std. 572. Therequirement to test cable and connectors could also be Interpreted as qualifying a"matched set". This could further lead to the Interpretation that every variation of

cable and connector must be type tested. It should also be noted that IEEE 383-2003now requires that coaxial, triaxial, and twinaxial cable be tested with their jacket toensure that Jacket integrity Is maintained. This is intended to ensure that jacketintegrity is maintained for qualified connectors and splices that rely on saidperformance.

IEEE recommendation: Delete Regulatory Position 3.

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Age Conditioning Cause 6.3, "Age-conditioning" should be supplemented to include aged

cable specimen and new splice kits; and a new splice kit combining an aged

cable with a new cable. IEEE comment: It Is believed that the requirement to combine In a new

cable splice with an aged cable is intended to demonstrate that the agedcable will not adversely affect the splice. This test configuration is notconsidered relevant to future qualification tests performed in accordancewith IEEE 383-2003. IEEE 383-2003 requires that a 20 X diameter mandrel

bend test be performed after normal environment thermal and radiationaging. This test demonstrates the cable jacketing material will retain someflexibility at the end of its qualified life. This effectively precludes Installingsplices onto embrittled cables within their specified qualified life. IEEE 383-1974 did not require this test if a similar 40 X diameter mandrel bend testwas performed after the accident exposure. The requirement for the

mandrel bend test after thermal and radiation aging is an enhancement tothe qualification type test defined in IEEE 383-2003. IEEE Recommendation: Delete Regulatory Position 7.

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Retained Flexibility 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 resistanceand signal attenuation limits".

IEEE Comment: The mandrel bend tests are intended totest the Integrity of the cable not establish a suitablelevel of electrical performance for specific instruments.The acceptable performance of an Instrument cable

during a OBE Is an installation specific evaluation whichis dependent on device type and cannot be determinedby the cable manufacturer or the test lab.

IEEE Recommendation: Delete Regulatory Position 8.

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NUGEQ CommentsNUGEQ Comments 10 Comments10 Comments -- Many the Same as IEEEMany the Same as IEEE

Condition Monitoring in DiscussionCondition Monitoring in Discussion Representative CableRepresentative Cable

Principle Qualification Criteria

Connectors Stranding Configuration

Identification

Age Conditioning

Retained Flexibility GeneralGeneral


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Condition Monitoring in DiscussionCondition Monitoring in Discussion

The NUGEQ disagrees. Detailed commentand recommended revision to wording areprovided as part of NUGEQ Comment 10.

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Representative CableRepresentative Cable

Thinks Intent UnclearThinks Intent Unclear – – If JustIf JustDocumentation, then already covered.Documentation, then already covered.

If requiring conductor attributes to be partIf requiring conductor attributes to be part

of representative sample, know of noof representative sample, know of nogrounds to add this complexity.grounds to add this complexity.

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Connectors

Disagrees with Identical Construction forDisagrees with Identical Construction forCoaxCoax – – Representative Cable Used in restRepresentative Cable Used in rest

of standard.of standard.

Connectors removed from IEEE 383.Connectors removed from IEEE 383.

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Stranding Configuration

Strand Configuration not defined. DeleteStrand Configuration not defined. Deleteor clarify.or clarify.

NUGEQ postulates may refer toNUGEQ postulates may refer to "stranding

configuration (round, compressed, orcompact)."

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Identification

Believe this is currently covered and onlyBelieve this is currently covered and onlyreferencing cable section.referencing cable section.

Either delete or add toEither delete or add to Clause 6.2.1.8 (for

cables) and 6.2.2.6 (for field splices)

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Age Conditioning Specifies two additional specimens, (new splice/aged cable

and new splice/aged & new cable), for qualification of field

splices. Assume basing on testing in NUREG/CR-6704 that was

largely due to handling damage to the severely embrittledinsulation/jacket materials during splice application.

Not relevant to future qualification tests, in part, becauseIEEE 323-2003 Clause 6.4.2d requires a 20D mandrel bendafter thermal and radiation aging. This test demonstratesthat the cable insulation materials retain some flexibility atthe end of their qualified life. This effectively precludes

installing splices onto embrittled insulating materials if thecables are within their specified qualified life. The prior version of IEEE 323 did not require this test if a

similar 40D mandrel bend test was performed after the

accident exposure.

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Retained Flexibility "The acceptance criteria for instrument cables

should specify the minimum acceptable insulationresistance and signal attenuation limits.“

Electrical tests no meaning in regards to this test

Notes clause 6.4.4 requires that the acceptancecriteria for applications be specified

Notes that acceptance criteria for instrument

cables will vary based on cable type andapplication

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GeneralGeneral The first part refers to date of manufacturer standards

associated with test specimen specification,

manufacture, and factory acceptance. This positionappears to be redundant to RP6 which requests similarinformation under Clause 6.2.2.6.

The second part requests documentation of

manufacturer inspection and maintenance requirements.The NUGEQ notes that Clause 4 currently requires thatqualification documentation include "Inspection andmaintenance requirements" but this requirement was notrestated in the general documentation guidance in

Clause 9.1. Consolidate the RP6 and RP9 guidance on test specimen

information into RP6 and limit RP9 guidance toInspection and Maintenance Requirements.

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Recommended use of cable CM programs isinconsistent with prior NRC conclusionsregarding cable CM. Also believe that the

IEEE considered and rejected incorporatingguidance on such CM during thedevelopment of IEEE 383-2003

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Westinghouse 3 CommentsWestinghouse 3 Comments

Section B (DG-1 132 Page 2, fourth paragraph) states that power and instrumentation and control(I&C) cables for which failures could disable risk-significant equipment should have conditionmonitoring programs to demonstrate that the cables can perform their safety function whenneeded.

A condition monitoring program does not demonstrate that the cables can perform their safetyrelated function; that is the purpose of qualification testing. Condition monitoring programs areused to assess the physical and operating condition of the cabling. The qualification programdemonstrates that the cables will perform their required safety-related function at the end ofqualified life under design basis accident (DBA) conditions.

Conditioning monitoring can be used to support aging assessments in conjunction with monitoringtemperature and radiation. Condition monitoring can be used to determine if qualified equipmentis suitable for further service based on its installed conditions. Usually when condition monitoringis applied one or more condition indicators are monitored to determine whether equipmentremains in a qualified condition. As the qualified equipment approaches the end of itsdemonstrated qualified life, condition monitoring results may be used to determine if anextension of qualified life is possible. When condition monitoring technologies become proven andcommercially available then they can become part of the plant maintenance/surveillance program

implemented by the utility. Conditioning monitoring should not be required as part of the EQ program, rather it should be

part of the plant maintenance/surveillance program. Westinghouse recommends deleting the last sentence of the fourth paragraph or revise it to

clarify the purpose of a condition monitoring program. Also, Regulatory Position C(2)(c) should bedeleted or clarified.

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DocumentationDocumentation

Regulatory Positions C(2)(a) and C(2)(b)request supplements to Clause 4 of IEEEStd 383-2003.

These positions are already included inIEEEE Std 383-2003, Clause 4. Theseexceptions should be deleted.

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Regulatory Position C(10) should bedeleted.

Condition monitoring does not

demonstrate that the cables can performtheir safety-related function.

See 1

st

comment.

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Exelon 2 CommentsExelon 2 Comments

On page 2, in the last paragraph in Section B,"Discussion," the NRC makes reference to "...field splices for medium-voltage cables ininaccessible locations should not be permitted...." Exelon/AmerGen request that the NRC provideclarification concerning the intent of thisstatement.

Specifically, is it the NRC's intent to precludepulling splices into inaccessible locations?

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On page 3, Section C, "Regulatory Position, Item10 states: "Power and instrumentation andcontrol cables for which failures could disablerisk-significant equipment should have condition

monitoring programs to demonstrate that thecables can perform their safety function whenneeded. " Exelon/AmerGen believe that thisissue warrants further discussion and requestthat additional clarification be provided in thefollowing areas:

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Risk Significant

A. The scope of DG-1 132 is primarily forClass 1 E cables located in harshenvironments. “Risk-significant”

equipment is not necessarily defined inscope of DG-1 132, and therefore,Exelon/AmerGen recommend clearly

defining the scope of the guidanceprovided in DG-1 132.

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GL 2007GL 2007--0101 B. Generic Letter (GL) 2007-01, "Inaccessible or

Underground Power Cable Failures that Disable AccidentMitigation Systems or Cause Plant Transients,“ recommends that licensees should have power cablecondition monitoring programs for Maintenance Rulesystems. The GL does not specifically mandate cablecondition monitoring programs, and the regulatory basisfor requiring a cable condition monitoring program is notestablished or clearly defined in any NRC documentation.Therefore, Exelon/AmerGen request further clarification

concerning the basis for requiring a cable conditionmonitoring program.

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Water ImmersionWater Immersion

C. DG-1 132 discusses that the need for equipment

qualification is to prevent common mode failure due toharsh environments resulting from a Design BasisEarthquake (DBE). As such, any cable conditionmonitoring program would be limited to those cables

whose qualification aging conditions were not consistentwith actual installed plant conditions. Exelon/AmerGenwould not expect to find too many Class 1E cables, whichwould be subject to a post DBE environment, to be in anyenvironment not enveloped by the qualification plan. One

possible exception would be if a Class 1E harshenvironment cable was continuously immersed in water;this probably would not be considered a qualification agingtechnique. Therefore, Exelon/AmerGen request furtherclarification concerning this issue.

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Harsh EnvironmentHarsh Environment

D. DG-1 132 explains that the need forequipment qualification is to prevent commonmode failure due to harsh environmentsresulting from a DBE. Section C, "Regulatory

Position," Item 10 does not limit the scope ofcable condition monitoring to cables in harshenvironments. There is no identified commoncause, other than the harsh environment, thatwould cause multiple cables to fail. Therefore,Exelon/AmerGen request further clarificationconcerning this issue.

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BenefitBenefit

E. DG-1 132 does not appear to include adiscussion about Regulatory Position Item 10 inthe Regulatory Analysis section of the draftRegulatory Guide. The Conclusion section

indicates that the proposed action will reduceunnecessary burden. Imposing cable conditionmonitoring programs could have a significantimpact on licensees with no clear benefit.Therefore, Exelon/AmerGen request furtherexplanation and clarification regarding theperceived benefit.

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No Condition Monitoring TechniqueNo Condition Monitoring Technique

F. Exelon/AmerGen does not believe that there is an assured means of

monitoring cables to determine if they can perform their intended safetyfunction. Comments were provided to the NRC on the draft GL 2007-01relative to this specific issue. The industry attempted to portray that cablecondition monitoring technology is not capable of determining theremaining life in a cable. HiPot testing will fault cables that have pre-existing conditions; however, many view this destructive testing

methodology as overly stressful on cables. This testing can potentially causefailures in cables that have considerable life remaining. Other non-destructive testing methodologies, such as Partial Discharge (PD) andPolarization Index (Tan-Delta), can provide advance indications of changesin the cable's characteristics, but there is not enough library information onthese tests to provide acceptance criteria. IEEE 400, "Guide for FieldTesting and Evaluation of the Insulation of Shielded Power Cable Systems,"does provide criteria for PD tests on XLPE insulated cables; however, EPRinsulated cables are predominant in the nuclear industry. EPR cables do nottrend linearly to failure; they tend to test well, and then cascade to failureover a period of a few months. Therefore, Exelon/AmerGen request thatthe NRC provide additional explanation and clarification concerning thebasis for cable condition monitoring.

Documents

DG-1132