Regulatory Guide 1.131

Qualification Tests of Electric Cables, Field Splices, and Connections for Light-Water-Cooled Nuclear Power Plants (for Comment)

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Issue date:	08/31/1977
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U.S. NUCLEAR REGULATORY COMMISSION

REGULATORY GUIDE

OFFICE OF STANDARDS DEVELOPMENT

REGULATORY GUIDE 1.131 QUALIFICATION TESTS OF ELECTRIC CABLES, FIELD SPLICES,

AND CONNECTIONS FOR LIGHT-WATER-COOLED

NUCLEAR POWER PLANTS

A. INTRODUCTION

Criterion III, "Design Control," of Appendix B,

"Quality Assurance Criteria for Nuclear Power Plants and Fuel Reprocessing Plants," to 10 CFR

Part 50, "Licensing of Production and Utilization Facilities," requires that, where a test program is used to verify the adequacy of a specific design feature, it include suitable qualification testing of a prototype unit under the most adverse design condi tions. This regulatory guide describes a method ac ceptable to the NRC staff for complying with the Commission's regulations with regard to qualifica tion testing of electric cables, field splices, and con nections for service in light-water-cooled nuclear powe~r plants to ensure that the cables, field splices, and connections can perform their safety-related functions.' The fire test provisions of this guide do the Insulated Conductors Committee of the Power Engineering Society of the Institute of Electrical and Electronics Engineers, Inc. (IEEE), approved by the IEEE Nuclear Power Engineering Committee, and subsequently approved by the IEEE Standards Board on February 28,1974. It was agooved as an ANSI

standard, ANSI N41.10-1975

1hpril

30, 1975. The standard delineates proce e

developing a program for qualificatio festingg cables, field splices, and connectioj* It plements IEEE Std 323-1974, "IEEE St; ioualifying Class IE

Equipment for N

aear ,

enerating Stations,"

which describe as'

re ements for equipment qualification. I

d'td

23-1974 is endorsed, with certain exoion'*f Regulatory Guide 1.89,

"Qualificati'

C

s IEE Equipment for Nuclear PowerAtlntL

not apply to quanttication for an installed contlgura- rtl'

te-' IEEE Std 383-1974 was issued, tion.

s ab atories and cable testing facilities ex r% c difficulty in producing a consistent flame by using the burner and flame source

B. DISCUSSION

cedures specified in the standar

d. An IEEE task IE

S 3e investigation into the problem was eventually IEEE Std 383-1974, "IEEE Standard for pe expanded to include an evaluation of various flame Test2 of Class IE Electric Cables, Field e

sources to determine if the 70,000 Btu/hr flame Connections for Nuclear Power eera i source specified in the standard was correct for use in Stations,"3 was prepared by Working G

p1 of fire qualification testing. The investigation found that inconsistencies in the flame source were traceable to

'Regulatory Guide 1.29, "Seismic Design Classification, provides the inadvertent use of incorrectly sized burners dur guidance with regard to identifying electric cables, field splices, ing certain tests.

and connections to which the desi rification requirements of Appendix B to 10 CFR Part 50

1

..

A

2As used in this regulatory guide'

t alification test" and A series of tests to determine if the correct flame

"type test" are synonymous.

source had been selected was conducted, and the

3Copies may be obtain he I titute of Electrical and results, as evaluated by the IEEE task force and the Electronics Engineers, nited neering Center, 345 East 47th NRC staff, indicated no basis for changing the 70,000

Street, New York,

0017.

Btu/hr. Investigation into fire testing is continuing by RE*

TORY GUIDES

Comments should be sent to the Secretary of the Commission, US. Nuclear Regu Regulatory Guides a L

d to describe and make available to the public methods latory Commission, Washington, D.C.

20555, Attention:' Docketing and Service acceptable to the NR q

.of implementing specific parts of the Commission's Branch.

r e g u l a t i o n s , to d e l i n~

e a t e N l u e s u s e d b y t h e s t a f f i n e v a l u a t i n g s p e c i f i c p r o b l e m sT

h g u d s u e i u d i n t e f l o n g e n b a d i v i n

or postulated accidents, or provide guidance to applicants. Regulatory Guides The guides e issued in the following ten broad divisions are not substitutes for regulations, and compliance with them is not required.

1. Power Reactors

6. Products Methods and solutions different from those set out in the guides will be accept-

2. Research and Test Reactors

7. Transportation able if they provide a basis for the findings requisite to the issuance or continuance

3. Fuels and Materials Facilities

8. Occupational Health of a permit or license by the Commission.

4. Environmental and Sitina o Anti ,

.. ...

M

Comments and suggestions for improvements in these guides are encouraged at all Materials and Plant Protection e

times, and guides will be revised, as appropriate, to accommodate comments and Requests for single copies of issued guides which may be reproduced) or for place to reflect new information or experience.

However, comments on this guide,if meet on an automatic distribution list for single copies of future guides in specific received within about two months after its issuance, will be particularly useful in divisions should be made in writing to the US. Nuclear Regulatory Commission, evaluating the need for an early revision.

Washington, D.C.

20555, Attention:

Director, Division of Document Control.

August 1977

IEEE and NRC, and significant results will be incor porated in future revisions of this guide.

The flame tests covered by Section 2.5 of the stan dard provide a test primarily of the self-extinguishing tendency of the cable insulation material. These tests are conducted with cables in a specific configuration and subjected to a defined fire source. However, the fire resistance of cables may vary significantly under different environmental conditions, cable configura tions, and fire sources. It should be recognized that the objective of the flame test is to provide guidance for the selection of fire-resistant cables rather than to establish the adequacy of the installation of cables in a nuclear power plant. Adequacy of cables as instal led depends on many factors. Morever, the adequacy of the cable system as installed depends on other fac tors in addition to the properties of the cables. For example, cable separation criteria are delineated in Regulatory Guide 1.75, "Physical Independence of Electric Systems," and fire protection guidelines are delineated in Regulatory Guide 1.120, "Fire Protec tion Guidelines for Nuclear Power Plants."

IEEE Std 383-1974 is concerned with cables both inside and outside the containment and establishes procedures for simulating operating conditions so that type testing will be adequate for the intended ser vice conditions. It covers normal operating and design basis event conditions, except that the fire test is a reference configuration and flame rather than the design basis configuration and flame.

C. REGULATORY POSITION

Conformance with the requirements of IEEE Std 383-1974, "IEEE Standard for Type Test of Class IE

Electric Cables, Field Splices, and Connections for Nuclear Power Generating Stations," is acceptable for qualifying electric cables, field splices, and con nections as components (Fite test provisions do not apply to qualification for an installed configuration)

for service in light-water-cooled nuclear power plants to ensure that the cables, field splices, and connec tions can perform their safety-related function sub ject to the following:

1. In lieu of Section 1.3.4.2.3, "Other Design Basis Events," -the following should be used:

"The remainder of the complete spectrum of design basis events (e.g., events such as a steam line break) shall be considered in case they represent different types or more severe hazards to cable operation."

2. In lieu of Section 1.3.5.3, "Test Design Basis Event," the following should be used:

""Type tests for design basis event conditions shall consist of subjecting non-aged and aged cables, field splices, and connections to a se- quence of environmental extremes that simulate the most severe postulated conditions of a design basis event and specified conditions of installation. Type tests shall demonstrate margin by application of multiple transients, in creased level, or other justifiable means.

Satisfactory performance of the cable will be evaluated by electrical and physical measure ments appropriate to the type of cable during or following the environmental cycle, or both. The factors for margin given in Section 6.3.1.5 of IEEE Std 323-1974 shall be used where ap plicable.

"The values of pressure, temperature, radia tion, chemical concentrations, humidity, and time in IEEE Std 323-1974 do not represent ac ceptable limits for all nuclear power stations.

The user of this standard shall ensure that the values used in the required type tests represent acceptable limits for the service conditions in which the cable or connections will be instal led."

3. In lieu of Section 2.1, "Introduction," the fol lowing should be used:

"Type tests deqcribed in this document are methods that shall be used to qualify electrical cables, field splices, and connections for use in nuclear power generating stations. Tests of the cable or connection assembly, as applicable, shall then supplement the cable tests in order to qualify the connections and other aspects uni que to planned usage.

"The values of pressure, temperature, radia tion, chemical concentrations, humidity, and time indicated in IEEE Std 323-1974 do not represent acceptable limits for all nuclear power generating stations.

"The user of this guide shall ensure that the values used in the required type tests represent acceptable limits for the service conditions in which the cable, or connections, or both, will be installed.

"Results of prior tests that are being used as the bases for the present tests shall be referenced in the documentation."

4. In lieu of Section 2.3.2, "Long-Term Physical Aging Properties," the following should be used:

"Aging data shall be submitted to establish long-term performance of the insulation. Data may be evaluated using the Arrhenius tech nique. A minimum of 3 data points, including

136°C and two or more others at least 10°C

apart in temperature, shall be used.

"If there is not sufficient evidence that ac celerated aging techniques can reliably produce

1.131-2 I_

end-of-life conditions, the following ongoing qualification procedure should be used:

"Ongoing Qualification Procedure-Some types of cables, field splices, and connections (hereafter referred to only as cables) may not respond in a representative manner to ac celerated aging techniques to establish end-of design-life conditions. Consequently, the qualified life would be less than the required design life. There are two suggested methods of achieving long-term (design life) qualification:

(a) After a planned period less than the qualified life of the cable has been reached, representative cables should be replaced with new cables and the removed cables subjected to a qualification test similar to that performed prior to installation. This test should include additional accelerated aging. Successful com pletion of this test extends the qualified life of the installed cables. This procedure should be repeated until the qualified life equals or ex ceeds the required design life. (b) Additional identical cables should be installed in a nuclear power generating station location where power loading and service conditions equal or exceed those of the cable to be qualified. A cable should be removed after a planned period less than the previously qualified life and subjected to a qualification test similar to that performed prior to installation. This test should include ac celerated aging. Successful completion of this test extends the qualified life of the installed cable. Sufficient additional identical cables should be initially installed in order that the above procedure can be repeated until the qualified life 'equals or exceeds the required design life.

"If the above methods demonstrate that the qualified life is less than the design life, a periodic replacement plan should be in stituted."

5. The radiological source term and exposure rate simulating LOCA conditions referred to in Section

2.4.2, "Radiation Exposure-Total," should be ob tained from Regulatory Guide 1.89 rather than from IEEE Std 323-1974.

6. In lieu of Section 2.5.1, "General," the follow ing should be used:

"This section describes the method for type testing of grouped cables via the vertical tray flame test to determine their relative self extinguishing tendencies. Testing shall include both aged and unaged cable specimens."

7. In lieu of Section 2.5.2.2, the following should be used:

"The fire test provisions of the standard are useful in screening out cable insulation materials that are inadequately self extinguishing, but they shall not be construed as qualification of any installed cable system con figuration. If field splices are to be used in cable trays, special provisions -shall be made to demonstrate that the fire retardant properties of the cable are not altered unacceptably in an adverse way by the field splice."

8. Section 2.5.4.2-Vertical tray configuration should be used and understood to mean perpen dicular to the plane of the horizon.

9. In lieu of Section 2.5.4.4, the following should be used:

"The gas burner flame source shall consume propane gas so as to release approximately

70,000 Btu per hour at an air-gas ratio of 5 to 1.

Natural grade propane shall be used. The procedure detailed below shall be followed:"

10. In lieu of the first sentence of Section 2.5.4.4.1, the following should be used:

"The ribbon gas burner' shall be mounted horizontally such that the flame impinges on the specimen midway between the tray rungs and so that the burner face is in front of and 4 inches from the cable and approximately 2 feet above the bottom of the tray."

11. In lieu of Section 2.5.4.4.3, the following should be used:

"Flame size will normally be achieved when the propane flow is 27.8 standard ft3 per hour and the air flow is 139 standard ft' per hour."

12. Section 2.5.4.5 is not endorsed by this regulatory guide.

13. The recommendations indicated by "should"

and the options indicated by "may" in the sections of IEEE Std 383-1974 indicated below have sufficient importance to be treated the same as requirements of the standard:

a. Section 1.3.1, "Cable Description"

b. Section 1.3.2, "Field Splices or Connection Description"

c. Section 1.3.4.1, "Meeting Service Conditions";

the first sentence.

'An American Gas Furnace Co. 10-in, 11-55 drilling, ribbon-type, catalog no. 10X 11-55 with an air-gaq Venturi mixer, catalog no.

14-18 (2 lbf/in2 max. gauge pressure) is the only presently available model that has been found satisfactory for purposes of these tests.

1.131-3

d. Section 1.3.4.2.1,

"Design Basis Event LOCA"

e. Section 1.4.1, "General"

f. Section 1.4.3, "Test Results"

g. Section 1.4.4, "Test Evaluation"

h. Section 2.2, "Type Test Samples"

i. Section 2.3.3, "Thermal and Radiation Ex posure"

j. Section 2.3.3.3 k. Section 2.3.3.4 i. Section 2.4.3, "LOCA Simulation"

m. Section 2.4.3.1 n. Section 2.4.3.2 o. Section 2.4.4, "Post LOCA Simulation Test"

p. Section 2.5.2.1 q. Section 2.5.4.3 r. Section 2.5.4.4.2 s. Section 2.5.5, "Evaluation"

t. Section 2.5.6, "Instrument Cable and Single Conductors from Multiconductor Assembly";

the recommendation that the tested cable pass a flame resistance test in accordance with ASTM

D2220-68.

14. Section 3, "References," of IEEE Std 383-1974 lists additional applicable IEEE standards. The specific applicability or acceptability of these referenced standards has been or will be covered separately in other regulatory guides, where ap propriate.

D. IMPLEMENTATION

The purpose of this section is to provide informa tion to applicants and licensees regarding the NRC

staff's plans for utilizing this regulatory guide.

Except in those cases in which the applicant proposes an acceptable alternative method, the method described herein for complying with specified portions of the Commission's regulations will be used by the staff in evaluating all construction nermit ap plications docketed after May 1, 1978.

UNITED STATES

NUCLEAR REGULATORY COMMISSION

WASHINGTON, D.C. 20555 FIRST CLASS MAIL

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PERMIT No. G-67 OFFICIAL BUSINESS

PENALTY FOR PRIVATE USE, $300

1.131.4