ML20214D167

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Forwards Electrical,Instrumentation & Control Sys Branch Supplemental Safety Evaluation of Wyle Labs Test Rept on Electrical Separation Verification Testing for CP&L 47879-02. Separation Distances of Raceway Sys Acceptable
ML20214D167
Person / Time
Site: Harris Duke Energy icon.png
Issue date: 02/15/1986
From: Rossi C
Office of Nuclear Reactor Regulation
To: Buckley B
Office of Nuclear Reactor Regulation
Shared Package
ML20214D170 List:
References
FOIA-86-760 TAC-05000400, TAC-5000400, NUDOCS 8602280731
Download: ML20214D167 (9)
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, FEB 15 5E6 MEMORANDUM FOR: Bartholomew Buckley, Proiect Manager, l Project Directorate #2 Division of PWR Licensing-A FROM: Charles E. Rossi, Assistant Director Division of PWR Licensing.A ,

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SUBJECT:

SHEARON HARRIS NUCLEAR POWER PLANT, UNIT 1 -

DOCKET NO. 50-400 .-

TEST REPORT ON ELECTRICAL SEPARATION VERIFICATION TESTING Plant Name: Shearon Harris Unit 1 Docket No.: 50-400 Licensing Status: OR ,

TAC No.: 05000400 Responsible Directorate: PWR-#2 Project Manager: B. Buckley Review Branch: EICSB(PWR-A)

Review Status: Complete Carolina Power and Light Company (CP&L), by letter November 21, 1985, submitted a copy of Wyle 1.aboratories Report, " Test Report on Electrical Separation Veri-fication. Testing for Carolina Power and Light Number 47879 02," to support the SHNPP compliance with Regulatory Guide 1.75, Revision 1, " Physical Independence of Electrical Systems." The Electrical, Instrurentation and Control Systems Branch / Division of PWR Licensing-A (EICSB/DPA) has prepared the enclosed evalua-tion of the Wyle Laboratories test report. Our evaluation is limited to the test methodology and test results of the report pertaining to electrical fires initiated by electrical faulte, occurring as a single failure during a design basis event. The minimum separation distances of SHNPP raceway system not meet-ing the requirements of R.G. 1.75 have been justified by testing and analysis, and therefore are acceptable.

/3

. . Charles E. Rossi, Assistant Director j , Division of PWR Licensing _A

Enclosure:

DISTRIBUTION As stated - Document Control 016 EICSB Rdg.,

cc: L. Rubenstein P. Gill (PF)(2)

J. E. Knight

Contact:

F. Rosa Paul Gill, EICSB/DPA C. E. Rossi X29417 Shearon H,arris S/F

  • See previous concurrence sheet TC :EIC5B/DPA :SL/EICS PA:BC/EICK :AD/DPA  :  : -

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OFFICIAL RECORD COPY '

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ENCLOSURE SHEARON HARRIS NUCLEAR POWER PLANT (SHNPP)

UNIT #1 - SUPPLEMENT TO SAFETY EVALUATION 8.3.1.30 Physical Independence of Redundant Safety-Related ,-

Systems The Carolina Power and Light Company, the applicant for Shearon Harris Unit 1 had committed to meet the requirements of Regulatory Guide 1.75 as stated in Section 8.3.1.2.14 of the FSAR. Subsequently, the applicant submitted an amend-  !

l ment to the FSAR identifying exceptions to the separation criteria of the Regu-latory Guide 1.75. The Shearon Harris electrical raceway system design was

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- based on the standard separation criteria contained in IEEE 384-1974 as endorsed

-- by R.G: 1.75. The applicant's amendment establishes lesser separation distances where they could not be maintained in accordance with R.G. 1.75, and justifies by (1) te.st, (2) analysis or (3) installation of suitable barriers. In order to provide justification for these lesser separation distances, the applicant instituted a test program conducted by Wyle Laboratories. The test program methodology and the test results are documented in Wyle Test Report No. 4787902.

The appl'ic' ant submitted the test results with associated information on the

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revised separation criteria dated November 21, 1985. The revised s'eparation distances are derived from Wyle laboratories test results and are being imple-mented in the Shearon Harris plant. This SER supplement focuses on the evalua-tion of these test results as the basis for the revised separation criteria.

Prior to initiation of the testing phase of the program, the applicant and Wyle Laboratories personr.el developed Test Procedure 47879-01,Re51sionA, i

which formed the basis of the tests. In order to perform a test program to e

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verify the adequacy of the raceway separation criteria, the test procedure 47879-01, Revisien A defined the worst case electrical failure that could be postulated to occur in a raceway. This worst case electrical failure was based on the following failure mode assumptions:

1) A cable in the SHNPP raceway system experiences a fault current in excess of the cable allowable energy let-thru (Irt) due to the postulated failure of the primary overcurrent protective device.
2) The fault current level is assumed to be just below the long time trip '

setpoint of the circuit secondary (upstream) overcurrent protective device so that the fault is not claared.

3) The fault current is conservatively maintained at a constant level until

} conductor open circuits or steady-state conditions are reached.

1 A fault current magnitude of 180 amperes was used for control cable tests to demonstrate that a worst case electrical fault does not have the potential to support combustion or have the capability to generate enough heat to adversely affect the operation of these cables. Five tests were performed for control cables for sizes ranging from 2/C 16 AWG to 3-1/C 6 AWG. The fault was assumed

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to occur between 120 volt panel and the load.

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A fault current magnitude of 704 amperes was used for power cables ty) to 2 AWG and 4200 amperes for power cables greater than 4/0 AWG. Six tests'were per-formed to determine which cable when energized with the rated fault current would produce the worst case electrical fault. The test results showed that Triplex 350 MCM cable was the worst case cable because it sustained the fault current longer and produced the most heat. Using this worst case cable (i.e.,

Triplex 350 MCM) three different configurations of the installed raceway design

- were tested to ' demonstrate the acceptability of the SHNPP raceway system. The three' raceway design configurations were as follows:

Test Configuration No.1 This configuration consisted of a twisted pair 16 AWG target cable separated 6 inches horizontally from a faulted Triplex 350 MCM cable in free air. This configuration represented field installation of free air cables going from the following:

1)~ Tray to tray s

2) Tray to conduit
3) Conduit to conduit
4) Tray / conduit to Equipment Test Configuration No. 2 s This configuration consisted of a free air cable, a cable in one inch rigid i  ;

conduit and a cable in flexible conduit. The purpose of this configuration was  :

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to demonstrate the acceptability of design where a rigid conduit, flexible con-duit, and a cable in free air are separated by less than 1/4 inch from each other for a worst case electrical fault.

Test Configuration No. 3

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This configuration consisted of two vertically separated horizontal cable trays, a horizontally separated vertical cable tray, a free air cable and a rigid con-duit. The purpose of this configuration was to demonstrate the acceptability

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of design for the following:

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1) Where a horizontal cable tray passes 12 inches from a vertical cable tray.
2) Where a 1 inch rigid steel conduit passes 1 inch below and perpendicular to the cable tray.

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3) Where'1 inch rigid steel conduit is separated 1 inch horizontally and runs

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parallel to the cable tray. ,

4) Where 1 inch rigid steel conduit is separated 1 inch horizontally from and perpendicular to the siderall of the tray.
5) Wh.re a free air cable passes horizontally 12 inches away fro and parallel to the faulted cable in the ladder rung tray.

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Before the beginning of each cable overcurrent (fault) test, baseline tests of

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target cable were performed. They consisted of insulation resistance measurements and a one minute high potential test. At the completion of the cable overcurrent test, post overcurrent tests were performed on each target cable. The post overcurrent tests consisted of the insulation resistance measurements and a one minute high potential test. The acceptability of the raceway design was based upon the condition that the target cable pass the post overcurren' t tests, as well as, show no physical damage to it.

A The Wyle Laboratories program with the above inputs and assumptions for the target cables demonstrated the acceptability of the raceway design for the following minimum separations:

1) Control free air cable or tray to Class IE raceway or cable with vertical separation distance of 1 inch.

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2) Low voltage power tray to Class IE free air cable, tray or flexible conduit with horizontal separation of 12 inches and vertical separation of 36 inches.
3) Low voltage tray to Class IE conduit with horizontal separation of 1 inch and vertical separation of 12 inches. e I i  !

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4) Low voltage free air gable to Class 1E free air cable, tray 'or flexible conduit with horizontal separation of 6 inches and vertical separation of 36 inches.

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5) Low voltage free air cable or tray to Class IE conduit with horizontal separation of 6 inches and vertical separation of 12 inches.
6) Conduit to Class IE tray or free air cable with separation of 1 inch.

Also in this test program the following raceway designs were demonstrated to be unacceptable because the target cable either showed physical damage or failed

  • the post overcurrent tests.

i . . .

i 1) Two free-air power cables separated by 6 inches horizontally.

2) A free-air power cable with other power cable in rigid and/or flexible conduit and separated by a distance of six inches vertically.
3) A power cable in a 1 inch rigid steel conduit and separated I inch ver'tically from another power cable.

- s The fault currents selected for the test progra'ms encompass the conditions which can result from failures of the overcurrent protective devices on the feeder cables. If the fault current should exceed the assumed values, it will cause either an upstream protective device operation or a rapi,d c6ble failure, there-by preventing long term overheating of cable to ignite fires. The postulated l

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- ICSB SALP IHPUT

  • PLANT: Shearon llarris Nuclear Power Plant, Unit 1

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SUBJECT:

Docket No. 50-400 i

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PERFOR!!ANCE BASIS i EVALUATION - **  ;

CATEGORY ...- . .

CRITERIA ..

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j Jan0gement N/A No basis for assessment. ,

4 wsivement ._

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i Approach to The licensee exhibited a clear understanding of the  !

' I technical issues involved.  ;

Res31ution of -  !

Technical Issues - i 1

3 The licensee has not responded in time and required an extension of

i. Responsiveness time.

1 ,

i N/A No basis for assessment. ,

.. Enfercement i i History 4

i N/A No basis for assessment.

j i. Reportable Events Staffing N/A No basis for assessment.

l 5.

4

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N/A

No basis for assessment.

l 7,. Training 4 -

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