ML20029A415
| ML20029A415 | |
| Person / Time | |
|---|---|
| Site: | North Anna  |
| Issue date: | 02/15/1991 |
| From: | Stewart W VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.) |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| 91-075, 91-75, NUDOCS 9102220024 | |
| Download: ML20029A415 (2) | |
Text
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YlltdlNIA ELECTitIC ANI) POWElt COMlwNY HICitMONI),YIltOINIA 200 61 February 15,1991
.U.S. Nuclear Regulatory Commission Serial No.91-075 Attention: Document Control Desk NL&P/JBL:Jmj Ri Washington, D.C. ' 20555 Docket No.
50 338 License No.
- Gentlemen:
_ VIRGINIA ELECTRIC AND POWER COMPANY NORTH ANNA POWER STATION UNIT 1 INSERVICE INSPECTION PROGRAM RELIEF REQUEST FROM ASME SECTION XI t(Y DROST ATIC PRESSURE TEST During the current refueling outage for North Anna Unit 1, we have scheduled replacement of two small valves. Pursuant to 10 CFR 50.55a(g)(5), relief is requested from certain post replacement pressure test requirements delineated in ASME Section XI,1983 Edition, Summer 1983 Addenda, for these ASME Section XI Class 2 valves.
Specifically, we have scheduled replacement of the blowdow'n system isolation valve, 1-MS-22, in line 1-1/2" SHPD 6 601-02 which taps into the "A" main steam line upstream of the main steam trip valve. The blowdown system isolation valve is'a 1-1/2
-inch socket weldod globe valve which has experienced leakage during hydrostatic testing of the blowdown line. Also, the chemical feed system isolation valve,1-WT-482, in line 2"-SGD-5-601_Q2 from the "B" steam generator also requires replacement during the outage. The chemical feed system isolation valve is a 2 inch socket welded:
gate valve which has experienced leakage during system operation. ln each of the above cases, replacement of the valve is considered the most appropriate resolution to.the ~ problem.
Following replacement welding for each of these valves, paragraph IWA-5214 of ASME Section Xl requires that a hydrostatic pressure test (in compliance with the system test pressure and temperature specified in IWC 5222) be performed on the -
affected area. As;no intermediate isolation exists for the subject valves, the pressure :
tests-would include the associated steam generator within-the hydrostatic test boundary._ Hydrostatic pressure testing of steam' generators is considered extremely-difficult and is impractical for this situation.' The number of steam generator hydrostatic i
. tests on the secondary side of the steam generators are limited. We propose not to l'
- use one of the hydrostatic tests for replacement of these valves.
In addition, j
hydrostatic pressure testing of valve 1-WT-482 would cause unrecessary personnel radiation exposure because of the valve's location. Also, testing can be accomplished L
-when system inservice testing at nominal operating temperature is performed on valve 1-MS-22.
9102220024 910215 PDR ADOCK 05o00338 0
y l
2S I
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As an alternative, we propose that a surface examination (PT) be performed on the completed socket welds prior to start up. In addition, a visual examination (VT 2) of the affected area will be conducted in conjunction with a system inservice test [lWA-5211(c)) at nominal operating temperature during the start up following the refueling outage. This test will be conducted when the system pressure is approximately 1000 psig. This proposed alternative testing methodology was previously requested on similar valve replacements for North Anna Units 1 and 2 (letter dated January 20, 1982, Serial No. 024) and approved by the NRC by letter dated February 24,1982.
Most recently for Virginia Electric and Power Company, relief was granted from performing similar post replacement hydrostatic pressure testing for Surry Power Station Unit 2 by letter dated August 29,1989.
It ls our position, that the proposed alternative meets the intended inspection required by the Code. NRC acceptance of this relief request would be consistent with previous requests concerning small sized valve replacements with no intermediate isolation from the steam generators. North Anna Unit 1 is schedule to start-up on March 5, 1991. We request NRC approval of this relief request prior to that date.
Very truly yours, m-n b $kN W. L. Stewart Senior Vice President - Nuclear cc:
U.S. Nuclear Regulatory Commission Region 11 101 Marietta Street, N.W.
Suite 2900 Atlanta, Georgia 30323 Mr. M. S. Lesser NRC Senior Resident inspector North Anna Power Station l
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