ML20245J671
| ML20245J671 | |
| Person / Time | |
|---|---|
| Site: | Summer  |
| Issue date: | 08/11/1989 |
| From: | Bradham O SOUTH CAROLINA ELECTRIC & GAS CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| NUDOCS 8908180121 | |
| Download: ML20245J671 (3) | |
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South C:rtlina Eltetric & G:s Compiny 01163 S. Eradh:m Je kan v SC 29065 Nuclear p tions SCE&G' August 11, 1989 sc,n, Document Control Desk U. S. Nuclear Regulatory Commission
. Washington, DC '20555 Attention: Mr. J. J. Hayes, Jr.
Subject:
' Virgil C. Summer Nuclear Station Docket No. 50/395 Operating License No. NPF-12 ASME Section XI Hydrostatic Testing of Steam Generator Blowdown System Gentlemen:
South Carolina Electric & Gas Company (SCE&G) hereby requests relief from ASME' Code /Section XI hydrostatic testing requirements for the Virgil C.
Summer Nuclear Station Unit No. 1 Main Steam (Nuclear) System. Details of this relief request are contained in the attachment to this letter.
This relief request is needed to support repair of main steam header moisture collector drain valves which are to be repaired during the fifth refueling outage scheduled to begin in March 1990. SCE&G requests that this relief be granted as soon as possible, but no later than December 31, 1989, in order to support planning activities for the refueling outage.
Should you have any questions concerning this matter, call at your convenience.
Very truly yours,
- 0. S. Bradham JBA/MDB/0SB: led Attachments l
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D. A. Nauman/0. W. Dixon, Jr./T. C. Nichols, Jr.
l E. C. Roberts l
W. A. Williams, Jr.
R. L. Prevatte S. D. Ebneter J. B. Knotts, Jr.
J. J. Hayes, Jr.
J. B. Archie General Managers M. D. Blue C. A. Price NSRC R. B. Clary NPCF K. E. Nodland RTS (NRR 890006)
J. C. Snelson File (810.19-2) i AoM U
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Page:1 of:2-HYDROSTATIC PRESSURE TESTING RELIEF REQUEST SYSTEM (MS) Main Steam System (Nuclear)
CODE CLASS 2
SYSTEM DRAWING NUMBER D-302-011-SYSTEM FUNCTION The main steam system (nuclear) functions to convey main steam from the steam
. generator to.the main steam isolation valves. Main steam is also provided to the emergency feedwater pump turbine.
SYSTEM REPAIR Valves XVT-02877-B, 02843A and 02843C are main steam header moisture collector drain valves. Due to numerous packing leaks on the valves at full operating plant loads, the valve stuffing boxes have been steam cut beyond repair; therefore.' complete replacement of the valves is required.
Replacement of.the' existing valves with' spare valves'will involve breaching the system pressure boundary.
SYSTEM TEST REQUIREMENTS Subsequent to repairs (n modifications by welding which penetrate the pressure boundary on piping greater than one inch diameter, a hydrostatic test on. piping where such repairs or modifications were performed is required.
Pursuant to ASME Code,Section XI, 1977 Edition through and including Summer 1978 Addenda, hydrostatic pressure is 1.25 Psv or 1470 PSI where Psv is the lowest pressure setting among the main steam safety valves.
BASIS FOR RELIEF i
Performing the required hydrostatic test on the MS piping subsequent to the modification would be extremely difficult, impractical and expensive due to the following:
1.
Potential for placing excess stress cycles on the steam generator shells.
- to Document Control Desk Letter August 11, 1989
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Page 2 of 2 2.
Potential for damage to system instrumentation.
3.
Potential for damage to main steam system and its hangers due to static loads caused by water solid condition.
4.
Potential for damage to steam generator tube bundles.
5.
Additional radiation exposure to personnel in the isolation and preparation of this system.
6.
The unnecessary pressurization of the secondary side of the steam generators and portions of the main feedwater system, steam genetitor blowdown system and the main steam system.
7.
The inability to maintain pressure due to potential leakage through the feedwater isolation valves, main steam isolation valves, and other valves connected to the system.
8.
Additional time and effort to pin or block main steam constant support and variable spring hangers.
9.
Additional time and effort to remove the main steam safety valves and blank the inlet piping and the potential for flange leakage after reinsta11ation.
- 10. Considerable time to isolate or remove instrumentation.
- 11. Alternative examinations specified will provide a level of confidence and quality equal to or better than the required testing per the ASME Code.
ALTERNATE EXAMINATIONS FOR STEAM GENERATOR BLOWDOWN SYSTEMS PIPING WELDS Prior to declaring the MS System operable, the following examinations will be performed on the affected MS System piping welds -- except for Item 4, which will be completed at the end of the First Inservice Inspection Interval:
1.
MT Examination on the root pass and final weld surface pursuant to ASME Code Section V, Article 7.
2.
Visual Examination.
3.
Perform Inservice Leak Test at nominal operating pressure.
4.
Perform Hydrostatic Test at the end of the 10 Year Interval.
Scheduled to be complete not later than December 31, 1994.
IMPLEMENTATION i
The alternate examinations will be performed in accordance with approved written procedures by qualified personnel after the repair.
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