ML20214Q813
| ML20214Q813 | |
| Person / Time | |
|---|---|
| Site: | Summer  |
| Issue date: | 05/29/1987 |
| From: | Nauman D SOUTH CAROLINA ELECTRIC & GAS CO. |
| To: | Murley T Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 8706050200 | |
| Download: ML20214Q813 (8) | |
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go,rng.gm18 Nuclear Operations SCE&G
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May 29,1987
- l Dr. Thomas E. Murley, Director Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Washington, DC 20555
Subject:
Virgil C. Summer Nuclear Station l
Docket No. 50/395 Operating License No. NPF-12 ASME Code,Section XI,
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HydrostaticTesting of Reactor Coolant Pump Sealinjection
Dear Dr. Murley:
i South Carolina Electric & Gas Company (SCE&G) hereby requests relief from the ASME Code /Section XI hydrostatic testing requirements for the Virgil C. Summer Nuclear Station Reactor Coolant Pump Seal Injection System. This relief request j
is needed to support weld repair to the Seal injection pipe at the Reactor Coolant Pump Thermal Barrier Flange. Details of this relief request are contained in the attachments to this letter.
1 Enclosed is the application fee of one hundred fifty dollars ($150.00) required by Title 10 of the Code of Federal Regulations, Part 170.
If you have any questions, please advise.
1 1
Vi uly hurs, A.
ian WRH: DAN /dwf Attachments c:
O. W. Dixon, Jr./T. C. Nichols, Jr.
C. L. Ligon (NSRC)
E. C. Roberts R. M. Campbell, Jr.
O. S. Bradham K. E. Nodland J. G. Connelly, Jr.
R. A.Stough D. R. Moore G. O. Percival W. A. Williams, Jr.
R. L. Prevatte Group Managers J. B. Knotts, Jr.
W. R. Baehr l&E Washington C. A. Price NPCF l
W. T. Frady File 8706050200 870529 PDR ADOCK 05000395 P
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ATTACHMENTI Pagal of 3 i
HYDROSTATIC TESTING OF REACTOR COOLANT PUMP SEAL INJECTION RELIEF REQUEST i
' SYSTEM Reactor Coolant Pump Sealinjection l
CODE CLASS 1
4 SYSTEM DRAWING NUMBER E-302-673 SYSTEM FUNCTION The Reactor Coolant Pump Seal injection System injects high pressure water through the Reactor Coolant Pump thermal barrier wall to:
1)
Act as a buffer to prevent Reactor Coolant System water from l
entering the lower pump radial bearing and pump seal section.
2)
Provide lubricating water to the lower pump radial bearing' and pump seal assembly.
WELD DEFECT DESCRIPTION AND PROBABLE CAUSE While in Mode 3 on May 26,1987, a live steam leak was discovered at the "C" Reactor Coolant Pump Thermal Barrier Flange and Reactor Coolant Pump Seal i
Injection pipe weld. The plant was placed in Mode 5 and the Reactor Coolant System was drained to half pipe.
i A Penetrant Test (PT) examination of the Reactor Coolant Pump Thermal Barrier Flange and Reactor Coolant Pump Seal Injection pipe weld revealed a 0.600" defect
.i in the flange base metal approximately 3/16" above the toe of the weld (see Attachments ll, Ill,IV). With the use of a pencil grinder the defect was chased in 1/8" l
increments and a PT examination was performed at each increment. The defect immediately propagated to the vicinity of the weld and flange material interface (see Attachment V). Subsequent grinding and PT examinations revealed that the defect propagated along the weld and the flange material interface to the Seal Injection pipe. The defect also propagated circumferentially along the weld and flange materialinterface to a circumferentiallength of approximately 2" at the.
root of the weld.
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Preliminary indications are that the defect originated in the root at the time the i
weld was performed. Because of possible cyclic fatigue and corrosive attack, the defect propagated alonct the flange and weld material interface. Conclusions as to the cause of cracking wif be provided in a supplement to this letter.
ATTACHMENTI
-l Page2 of 3 PT examinations of "A" and "B" Reactor Coolant Pump Seal injection piping revealed no defects.
SYSTEM TEST REQUIREMENTS Subsequent to repairs by welding on pipi,ng within the system boundary, a hydrostatic test is to be conducted on piping where such repairs were performed.
Pursuant to ASME Code Section XI,1977 Edition and including Summer 1978 Addenda, hydrostatic test pressure is 1.10 Po or 2574 psig at 100 F where Po is the normal operating pressure of sealinjection at 100% rated reactor power.
1 BASIS FOR RELIEF The Hydrostatic fest on the Reactor Coolant Pump Seal injection piping is not considered nece'ssary because:
1)
Repair work complies with Section XI.
2)
Catastrophic failure of repair would not represent an unanalyzed condition i.e., small break LOCA.
3)
Will expend a pressure test cycle which may require new fatigue evaluations.
Performing the rec uired Hydrostatic Test on the Reactor Coolant Pump Seal Injection piping su asequent to the weld repair would not be desirable for the 1
following reasons:
o Potential for damage to the Reactor Coolant Pump Seal Assemblies.
1 e Isolation and preparation of the Reactor Coolant Pump Seal Injection system would result in additional radiation exposure to personnel.
- Requirement for removal and replacement of the Reactor Coolant System Pressurizer Safety Valves.
e Requirement for defueling and refueling the core. This creates the possibility of damaging the fuel during defueling and refueling.
e Needless exposure of the Reactor Coolant System and the Reactor Coolant Pump Seal Injection System to thermal and hydraulic cyclic stresses. These stresses could cause other problems to occur.
e Potential for damage to system instrumentation and necessary repair.
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- ATTACHMENTI
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Pag 2 3 cf 3 in addition to the above reasons, the alternative examin'ation specified will provide a level of confidence and quality equal to or better than the required testing per ASME Code.
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. ALTERNATE EXAMINATION FOR REACTOR COOLAN_T PUMP SEAL INJECTION PlPING WELD Prior to entering Mode 2, the following examinations will be performed on the affected Reactor Coolant Pump Seal Injection piping welds, except item 5, which will be completed at the end of the next inservice inspection interval:
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PT examination on the root pass wcld surface pursuant to.
- ASME Code Section V, Article 5.
2)
PT examination on each groove weld pass and final grcove weld pass surface pursuant to ASME Ccde Section V, Article 5.
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3)
PT exam nat on on t e inal rein orcement passweld surface pursuant to ASME Code Section V, Article 5.
4)
Performance of InserviceILeak Test VT-2 examination at
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nominal operating pressure and temperature.
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5)
Performance of HydrostaticTest at the end of the 10 year interval.
f IMPLEMENTATION The alternate examination, items 1 through 3, will be serformed in accordance with approved written procedures by qualified personnel c uring and upon completion
, --of the Reactor Coolant Pump Seal Injection pipe weld repair. The performance of an inservice leaktett will be performed during heat up prior to entering Mode 2.
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-INPELLER SOUTH CAROUNA ELECTRIC & GAS CO.
VIRG!L C. SUMMER NUCLEAR STATION Reactor Coolant Controlled Leakage Pump Figure 5.5-1
ATTACIDIENT III
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OVERHEAD VIEW OF THE REACTOR COOLAtTP l
PUMP (WITHOUT MOTOR) l
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ATTACHMENTIV M
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THERMAL BARRIER FLANGE SECTION AA (NOT TO SCALE-ILLUSTRATION ONLY)
ATTACHMENT V E
E PIPE SIZE: 11/2" NPS SCH 80 (0.200")
304 SST 4
SECTION AA
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FORGE MATERIAL: 304 SST WELD DEFECT AND PROPAGATION g
f CROSS-SECTION OF REACTOR COOLANT PUMP SEAL lNJECTION PIPE AND THERMAL BARRIER FLANGE (NOT TO SCALE-ILLUSTRATION ONLY) 1
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