ML18036B287
| ML18036B287 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry  |
| Issue date: | 05/16/1993 |
| From: | Salas P TENNESSEE VALLEY AUTHORITY |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| NUDOCS 9305200304 | |
| Download: ML18036B287 (10) | |
Text
ACCEI ERAT DOCUMENT DIST UTION SYSTEM REGULAT INFORMATION DISTRIBUTION STEM (RIDS)
ACCESSION NBR:9305200304 DOC.DATE: 93/05/16 NOTARIZED: NO DOCKET FACIL;50-260 Browns Ferry Nuclear Power Station, Unit 2, Tennessee 05000260 AUTH.NAME AUTHOR AFFILIATION SALAS,P.
Tennessee Valley Authority RECIP.NAME RECIPIENT AFFILIATION Document Control Branch (Document Control Desk)
SUBJECT:
Forwards Request for Relief SPT-6 from ASME Section XI inservice sys test program for Valve 'FCV 68-33 bonnet-to-body bolting. Util will perform visual test w/studs in place in lieu of requirement for studs removed.
DISTRIBUTION CODE:
A047D COPIES RECEIVED:LTR ENCL i
SIZE:
TITLE: OR Submittal: Inservice/Testing/Relief from ASME Code NOTES:
RECIPIENT ID CODE/NAME PD2-4 ROSS,T.
COPIES LTTR ENCL 1
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2 RECIPIENT ID CODE/NAME PD2-4-PD COPIES LTTR ENCL 1
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6 NRR/DE/EMEB 1
1 OC/LFMB 1
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1 ES/DSIR/EIB 1
1 EG6G RANSOME,C 1
1 NSIC 1
1 1
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1 1
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1 1
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NOTE TO ALL"RIDS" RECIPIENTS:
PLEASE HELP US TO REDUCE WASTEI CONTACT THE DOCUMENT CONTROL DESK, ROOM Pl-37 (EXT. 504-2065) TO ELIMINATEYOUR NAME FROM DISTRIBUTION LISIS FOR DOCUMENTS YOU DON'T NEED!
TOTAL NUMBER OF COPIES REQUIRED:
LTTR 21 ENCL 18
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Tennessee Valley Authority, Post Office Box 2000. Decatur, Alabama 35609 NN St'W>3 10 CFR 50. 55a(g) (5) (iii)
U.S. Nuclear Regulatory Commission ATTN:
Document Control Desk Washington, D.C.
20555 Gentlemen:
In the Matter of Tennessee Valley Authority Docket No.
50-260 BROWNS FERRY NUCLEAR PLANT (BFN) UNIT 2-AMERICAN SOCIETY OF MECHANICAL ENGINEERS (ASME) SECTION XI INSERVICE SYSTEM PRESSURE TEST PROGRAM REQUEST FOR RELIEF FOR VALVE FCV 68-33 BONNET-TO-BODY BOLTING In accordance with the provisions of 10 CFR 50.4 and 10 CFR 50.55a(g)(5)(iii),
BFN is submitting a Request for Relief from the specified Section XI system pressure testing requirements of the 1986 Edition of the ASME Boiler and Pressure Code for NRC review.
The details of the Request for Relief and technical basis are contained in the enclosure.
During the conduct of the Code Class 1 leakage test following completion of the Cycle 6 refueling outage, leakage was discovered at the recirculation valve FCV-68-33 bonnet-to-body bolting.
In view of the difficulty encountered in BFN's efforts to remove the bonnet-to-valve bolting, and considering the hardship that would be imposed should galling of the stud-to-valve body occur due to additional forces being exerted on the studs, BFN requests NRC approval of the enclosed Request for Relief.
TVA proposes to perform a visual test VT-1 examination in accordance with ASME Section XI Code requirements with the studs in place in lieu of the ASME Section XI Code required VT-3 with the studs removed.
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'st305200304 930516 PDR ADOCK 05000260 p
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U.S. Nuclear Regulatory Commission
%6 ]99 If you have any questions, please telephone me at (205) 729-2636.
Sincerely, Pedro Salas Manager of Site, Licensing Enclosure cc (Enclosure):
NRC Resident Inspector Browns Ferry Nuclear Plant Route 12, Box 637
- Athens, Alabama 35611 Mr. Thierry M. Ross, Project Manager U.S. Nuclear Regulatory Commission One White Flint, North 11555 Rockville Pike Rockville, Maryland 20852'.
U.S. Nuclear Regulatory Commission Region II 101 Marietta Street, NW, Suite 2900 Atlanta, Georgia 30323'
0
ENCLOSURE REQUEST FOR RELIEF SPT-6 System:
Drawing:
Component:
Class:
Function:
Reactor Coolant (68) 47E817-1 (FSAR Figure 4.3-2a Sheet 2)
Recirculation valve FCV-68-33 bonnet-to-body bolting Pressure retaining bolting Impractical Test Requirement:
IWA-5250(a) The source of leakage detected during the conduct of a system pressure test shall be located and evaluated by the Owner for corrective measures as follows: (2) if leakage occurs at a bolted connection, the bolting shall be removed, VT-3 visually examined for corrosion, and evaluated in accordance with IWA-3100; Basis For Relief:
During conduct of the Code Class 1 leakage test following completion of the Cycle 6 refueling outage, leakage was discovered at the bonnet-to-body bolting.
These studs are 1-3/4 inch diameter, A540 Grade B23 material.
The valve body is A351 Grade CF8 material.
BFN has been unsuccessful in removing the studs for the VT-3, visual examination.
The studs were soaked in penetrating oil for 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> prior to attempting removal.
A force of approximately 2000 foot-pounds was applied to several of the studs with no resulting movement.
The valve manufacturer, Anchor Darling, recommended that a force of 2300 foot-pounds on the studs not be exceeded to ensure that galling of the studs does not occur.
The normal torque value for the studs is 1351 foot-pounds (maximum) per Anchor Darling Vendor Manual.
Should galling of the stud to valve body occur due to additional force being exerted on the studs, it would be necessary to rethread the valve body.
Rethreading of the valve body would require removal of the valve bonnet.
This valve cannot be isolated from the reactor vessel.
Removal of the valve bonnet would require that the drywell head and the reactor vessel head be removed to allow plugging of the jet pumps.
The performance of this work would require approximately two to three weeks.
0 I
The estimated exposure for this work is approximately 17 manrem..
This estimate is based on a crew of two
- men, a galling rate of'0%,
a stud removal rate of two hours and rethreading rate of 14 hours1.62037e-4 days <br />0.00389 hours <br />2.314815e-5 weeks <br />5.327e-6 months <br /> per galled
- stud, and a radiation field of 40 mrem.
This hardship due 'to personnel radiation exposure and addition unit down time is excessive in light of the small additional safety margin achieved by removal of the studs above the proposed alternative examination.
Alternate Testing:
'Approximately four inches of each of the 24 studs is visible between the bonnet, flange and the valve body.
Both the ends of the studs are also visible.
BFN proposes to perform a VT-1 visual examination of all 24'tuds in place in accordance with Examination Category B-G-2, Item No. B7.70 of Table IWB-2500-1 of Section XI of the ASME Boiler and Pressure Vessel Code.
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