TXX-6019, Interim Deficiency Rept CP-86-50 Re Nut Alignment & Torque Requirements for Unistrut Spring Nuts on Instrument Mounts. Initially Reported on 860716.Drawings for Instrument Racks & Tubing Supports Revised.Next Rept Expected by 870221
| ML20203N989 | |
| Person / Time | |
|---|---|
| Site: | Comanche Peak  |
| Issue date: | 10/10/1986 |
| From: | Counsil W TEXAS UTILITIES ELECTRIC CO. (TU ELECTRIC) |
| To: | Johnson E NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV) |
| References | |
| CP-86-50, TXX-6019, NUDOCS 8610200172 | |
| Download: ML20203N989 (2) | |
Text
Log # TXX-6019
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File # 10110 903.10 TEXAS UTILITIES GENERATING COMPANY SEYWAY TOWER. 4ee NORTH OBJVE STREET, L R. et. DA11AS. TEXA5 76301 October 10, 1986 U.Y$".hff.UE
%@@gggh OCr i 426 Mr. Eric H. Johnson, Director Division of Reactor Safety and Projects y
U. S. Nuclear Regulatory Commission 611 Ryan Plaza Drive, Suite 1000 Arlington, TX 76012
SUBJECT:
COMANCHE PEAK STEAM ELECTRIC STATION (CPSES)
DOCKET NOS. 50-445 AND 50-446 UNISTRUT SPRING NUTS ON INSTRUMENT SUPPORTS SDAR: CP-86-50 (INTERIM REPORT)
Dear Mr. Johnson:
On July 16, 1986, we verbally notified your Mr. I. Barnes of a deficiency involving nut alignment and torque requirements for Unistrut spring nuts on instrument mounts. We have submitted an interim report logged TXX-4968, dated August 18, 1986. We are reporting this issue under the provisions of 10CFR50.55(e) and the required information follows.
DESCRIPTION MD SAFETY IMPLICATIONS The Unistrut fasteners used on instrumentation mounts in CPSES Unit I have been observed to be improperly tightened and/or misaligned. A misaligned nut, if properly torqued, does not constitute a significant deficiency.
Improperly torqued nuts could result in loose connections and affect the safety of operations due to the potential for common mode failure of instrument supports during or after a seismic event.
CORRECTIVE ACTION In order to correct the deficiency, the drawings and specifications for instrument racks, and instrument and tubing support details have been revised to incorporate specific torque values.
Inspection and construction procedures will be raviewed to determine the need for corresponding revisions.
Currently, we are developing an integrated plan requiring 100*/. rework of all installations possibly affected by this deficiency. This plan, including rework, is scheduled for completion no later than July 1, 1937.
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O TXX-6019 Detober 10, 1986 Page 2 We anticipate submitting our next report no later than February 21, 1987.
Very truly yours, Y
TVYb W. G. Counsil JCH/amb c - NRC Region IV (0 + 1 copy)
Director, Inspection & Enforcement (15 copies)
U. S. Nuclear Regulatory Commission Washington, D. C.
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