TXX-6054, Interim Deficiency Rept CP-86-53 Re Deficient Seismic Design Condition Involving Support of Electrical Conduit.Initially Reported on 860725.Testing Program Scheduled to Evaluate Adhesives or Clamps.Next Rept by 861210
| ML20211F104 | |
| Person / Time | |
|---|---|
| Site: | Comanche Peak  |
| Issue date: | 10/21/1986 |
| From: | Counsil W, Keeley G TEXAS UTILITIES ELECTRIC CO. (TU ELECTRIC) |
| To: | Johnson E NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV) |
| References | |
| CP-86-53, TXX-6054, NUDOCS 8610310053 | |
| Download: ML20211F104 (2) | |
Text
DALLAS-SLIC TEL No.
214 979 8700 Oct 21.86 17:07 P.07 ci Log # TXX-6054 File # 10110 l
903.10 TEXAS UTILITIES GENERATING COMPANY SEYW AT TOWER e goo NORT1s olive sTSERT, L.B. e3. DALLAS, TEXA8 98503 October 21, 1986
.5%^JA/AfnD N@$0\\V/IM Mr. Eric H. Johnson, Director F
Division of Reactor Safety and Projects i
OCT 2 l 1986 c
U. S. Nuclear Regulatory Commission
!q )'
l 611 Ryan Plaza Drive, Suite 1000 Arlington, TX 76012 i
SUBJECT:
COMANCHE PEAK STEAM ELECTRIC STATION (CPSES)
DOCKET NOS. 50-445 AND 50-446 SEISMIC DESIGN OF CONDUIT SDAR: CP-86-53 (INTERIM REPORT)
Dear Mr. Johnson:
On July 25, 1986, we verbally notified your Mr. I. Barnes of a deficiency involving the seismic design of conduit. We have submitted an interim report logged TXX-4982, dated August 22, 1986. We are reporting this issue under the provisions of 10CFR50.55(e) and the required information follows.
DESCRIPTION During performance of the Unit 2 conduit structural analysis, a deficient design condition was observed involving the support of electrical conduit.
The specific condition occurs when the conduit changes direction and terminates in an airdrop and no support is provided between the change in direction and the airdrops.
In the event a coupling is installed prior to the change in direction, the unsupported portion of the conduit may result in a torsional moment on the coupling during a seismic event. The inability of the coupling to resist the torsional moment could result in excessive motions at the free end of the conduit which would be resisted only by the cable. The cable or cable terminations have not been designed for these loading conditions.
Analysis and evaluation of these conditions have determined that couplings on unsupported airdrops could rotate causing damage to the cables. This issue is applicable to certain Unit 1 & 2 unsupported airdrops on.A and B Train conduits, and C Train conduits over 2 inches in diameter.
SAFETY IMPLICATIONS In the event the deficiency had remained undetected, this condition could have adversely affected the ability of safety-related systems to perform as required for safe operation and shutdown during a seismic event.
8610310053 861021 PDR ADOCK 05000445 S
PDR 4 omason or Tux 4e urarrras at.scrarC COtt7ANY Q
DALLAS-SLIC TEL No.
214 979 8700 Oct 21.86 17:08 P.08 TXX-6054 October 21, 1986 g
Page 2 CORRECTIVE ACTION In order to provide corrective measures, a testing program has been scheduled to evaluate the ability of adhesives or clamps, applied to the conduit coupling after installation, to resist torsional moments.
We estimate completion of this testing by November 13, 1986. Our evaluation of the results and identification of selected corrective actions will be completed by November 17, 1986.
We anticipate submitting our next report December 10, 1986.
Very truly yours, b
W. G. Coun il By:_ s v5-G.S. Keeley
/
Manager, Nuclear ensing JCH/mlh c - NRC Region IV (0 + 1 copy)
Director, Inspection & Enforcement (15 copies)
U. S. Nuclear Regulatory Commission Washington, D. C.
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