ML20044G765
| ML20044G765 | |
| Person / Time | |
|---|---|
| Site: | Sequoyah  |
| Issue date: | 05/28/1993 |
| From: | Fenech R TENNESSEE VALLEY AUTHORITY |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| NUDOCS 9306040226 | |
| Download: ML20044G765 (5) | |
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Tennessee Vaney Authonty, Post Off ce Box 2000. Soday-Dasy. Tennessee 37379 2000
-l Robert A. Fenech Vce President. Sequoyan Nuclear Plant i
May 28, 1993
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U.S. Nuclear Regulatory Commission ATTN: Document Control Desk r
Washington, D.C. 20555
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Gentlemen; In the Matter of
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Docket Nos. 50-327 Tennessee Valley Authority
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50-328 SEQUOYAH NUCLEAR PLANT (SQN) - ADDITIONAL INFORMATION FOR IN-SERVICE PRESSURE TEST (ISPT) RELIEF REQtiESTS ISPT-2, -3, AND -4 i
Reference:
TVA letter to NRC dated November 17, 1992, "Sequoyah Nuclear Plant (SQN) - Units 1 and 2 - Revision to In-Service Pressure.
'l Test (ISPT) Program in Support of' Cycle 6 Refueling ~0utages" In the referenced letter, TVA submitted three relief requests associated' with SQN's ISPT program. The three relief requests'(ISPT-2,.and -4) were new relief requests associated with American Society of.' Mechanical Engineers pressure tests activities that were scheduled for SQN's Unit 1
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Cycle 6 refueling outage.
During a telephone conference call on April 21, 1993, NRC requested "I
specific additional information to support staff review of the subject-relief requests.
Enclosed is the requested information for ISPT-2 and j
-3.
In addition, please note that TVA is withdrawing' relief request ISPT-4.
Further review'has identified that the piping configuration.is-i such that the appropriate code hydrostatic tests may be performed.
i Please direct questions concerning this issue to D. V. Goodin at j
(615) 843-7734.
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-Sincerely, d
le py
- Robert A. Fene e
.f Enclosure c t. : See page.2
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9306040226 930528-j PDR ADOCK.05000327 H
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4 U.S. Nuclear Regulatory Commission Page 2 l
May 28, 1993 cc (Enclosure):
Mr. D._E. LaBarge, Project Manager d
U.S. Nuclear Regulatory Commission One White Flint, North 11555 Rockville Pike Rockville,-Maryland 20852-2739 NRC-Resident Inspector Sequoyah Nuclear Plant 2600 Igou Ferry Road Soddy-Daisy, Tennessee 37379-3624 Regional Administrator U.S.. Nuclear Regulatory Commission Region II 101 Marietta Street, NW, Suite 2900 Atlanta, Georgia 30323-2711
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t ENCLOSURE Additional Information for In-Service Pressure Test (ISPT) Relief Requests Eclief_Raquest JSEI:2 NRC Request Summarize any nondestructive examination (NDE) that has been performed on I
the pressure-boundary piping because of repairs and describe what
- l in-service NDE is performed. Also conceptually describe the preservice and/or construction exams that were performed on the pressure boundary piping.
i TVA Response There are four different pipe sizes within the ISPT-2 piping boundary:
10 inches, 6 inches, 2 inches, and 1 1/2 inches. The following is a l
list, by size, of the construction code NDE requirements for this piping:
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10-inch piping: Fit-up.(preweld inspection).
Final visual (postweld inspection)
Dye penetrant Radiograph 1
6-inch piping: Fit-up (preweld inspection) f Final visual (postweld inspection)
.i Dye penetrant l
Radiograph l
2-inch piping: Fit-up (preweld-inspection)
I Final visual (postweld inspection)
-i Dye Penetrant i
1 1/2-inch piping: Fit-up (preweld inspection)
Final visual (postweld inspection)
Dye Penetrant The. requirements performed for preservice and in-service examinations are found in SQN's In-Service Inspection (ISI) Program.
The requirements are, as follows:
1.
For pipe size equal to and greater than four-inch nominal pipe size.,
ultrasonic and dye penetrant examinations are required.
- i 2.
For pipe size less than four-inch nominal pipe size, dye penetrant examinations are required.
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3.
In accordance with SQN's code of record for IS1,'25 percent offthe l
tota 1' population of Class 1 piping welds are required to receive an:
IS1 during the first 10-year interval. This means that the total l
population of Claes 1 welds will receive one ISI during the 40-year.
life of the plant. _ Construction code NDE and preservice. examinations l
are performed after repairs or replacement by welding.
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-f The following check valves within the ISPT-2 piping boundary were
-replaced during the first 10-year interval:
Valve 1-63-551, Work Request (WR) C003957 Pipe size is 2 inches,. Schedule 160, American Society of Mechanical-Engineers (ASME) SA 376 Type 304 Coupling size is 2 inches, 6000#, ASME SA 182 Type 304 Valve size is 2 inches, 1500#, Body ASME SA 182 Type 316 Valve 2-63-559, WP M8427-01 Pipe size is 2 inches, Schedule 160, ASME SA 312 Type-316:
Valve size is 6 inches, 2500#, Body ASME SA 182 Type 304 Valve 2-63-587, WR C074865 Valve size is 1 1/2 inches, 1500#, Body ASME SA 182 Type 316' Valve 2-63-588, WR C045949 Pipe' size is 1 1/2 inches, Schedule 160, ASME SA 376 Type 304 Valve size is 1 1/2 inches, 1500#, Body ASME SA 182 Type 316 t
Valve 2-63-589, WR C074524 i
Pipe size is 1 1/2 inches,' Schedule 160, ASME SA 376 Type 316 Valve size is 1 1/2 inches, 1500#, ASME SA 182 Type 316 The construction code NDE and the preservice examinations previously described were performed for the above valve and pipe replacements. No further repair or replacements on any pipe welds have been performed i
within the scope of ISPT-2.
I Belief Request ISPT-3 i
NRC Request
- 1. _ Clarify the " basis for relief" by distinguishing between pressure.
testing the piping in Mode 3 and pressure testing the piping.in Mode 6.
It is not clear, which mode (Mode 3 or Mode 6) estimates previously provided in TVA's November 17, 1992, letter apply.
2.
Provide any preservice/in-service NDE history and repair history (if any) for the pressure-boundary piping to ensure that. structural _
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integrity of the piping has been maintained.
't TVA Response Performance of the pressure test during Mode 3 requires that the isolation valves be opened with the reactor coolant system (RCS) at full.
pressure and temperature (2235 pounds per square inch. gauge, 547 degrees Fahrenheit).
Personnel safety Lconcerns have been raised for this mode of testing.
The concerns are as follows:
1.
If the test is' performed while in Mode 3 during plant shutdown, there is a concern that the gasket may have degraded over the course;of jan operational cycle because of high heat, and fail when the isolation valve is opened and full RCS pressure is applied to the blind flange and gasket. Since the' test personnel would be directly facing the
e valve and blind flange when opening the valve, the potential exists for exposing the personnel to high-temperature, high-pressure RCS fluid.
2.
If the test is performed in Mode 3 during plant start-up, the came concerns will exist for those blind flanges that may not be opened during a plant shutdown. The piping between the isolation valve and the blind flange will contain pressurized fluid for the remainder of the operating cycle even after the isolation valve is closed. When the unit is brought down again for the next refueling outage, the same potential for personnel injury would exist for maintenance personnel when removing blind flanges for venting, draining, or any other maintenance activities on the RCS.
Performance of the pressure test in Mode 6 presents an as low as reasonably achievable concern.
Each of the blind flanges would have to be removed, a test flange' installed, and a hydrostatic pump connected.
i Personnel would remain in the area to perform the test, disconnect the-test equipment, and reinstall the blind flange. The dose estimates provided for ISPT-3 in'TVA's November 17, 1992, letter were based on this method of testing.
There have been no repairs or replacements on any pipe welds within the scope of ISPT-3.
Piping within the scope of ISPT-3 is either 3/4-inch or 2-inch diameter.
t The 3/4-inch-diameter piping (piping with blind flange connections) is exempt from ISI because of size. The 2-inch-diameter pipe (pipe without blind flanges) is included in the ISI program. _ There are 25 welds within the 2-inch-diameter piping that have been examined under the'ISI program using the liquid penetrant method. All welds were accepted.
One weld had a 3/4-inch linear indication that was removed.
The weld was reexamined and found acceptable.
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