ML18037A986
| ML18037A986 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry  |
| Issue date: | 07/08/1994 |
| From: | Salas P TENNESSEE VALLEY AUTHORITY |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| NUDOCS 9407190440 | |
| Download: ML18037A986 (24) | |
Text
REGULATORY INFORMATION DISTRIBUTION SYSTEM (RIDS)'CCESSION NBR:9407190440 DOC.DATE: 94/07/08 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:
Submits request for relief from 1986 Edition of ASME Boiler
& Pressure Vessel Code,IWA-5250(a)(2),sys pressure test requirements for BFN Unit 2.
DISTRIBUTION CODE:
A047D COPIES RECEIVED:LTR ENCL SIZE:
TITLE: OR Submittal: Inservice/Testing/Relief from ASME Code GL-8 -04 NOTES:
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RECIPIENT ID CODE/NAME PD2-4 TRIMBLE,D INTERNAL: ACRS NRR/DE/EMEB NUDOCS-ABSTRACT OGC/HDS3 RES/DSIR/EIB EXTERNAL EG&G BROWNi B NRC PDR COPIES LTTR ENCL 1
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2 RECIPIENT ID CODE/NAME PD2-4-PD AEOD/DSP/ROAB NRR/EMCB OC/LFDCB RB~
01 EG&G RANSOME,C NSIC COPIES LTTR ENCL 1
1 1
1 1
1 1
0 1
1 1
1 1
1 NOTE TO ALL'RIDS"RECIPIENTS:
PLEASE HELP US TO REDUCE WASTE! CONTACTTHE DOCUMENTCONTROL DESK, ROOM Pl-37 (EXT. 504-2083 ) TO ELIMINATEYOUR NAMEI'ROM DISTRIBUTIONLISTS FOR DOCUMENTS YOU DON'T NEED!
TOTAL NUMBER OF COPIES REQUIRED:
LTTR 22 ENCL 19
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Tennessee Valley Authority, Post Oflice Box 2000, Decatur, Alabama 35609 July 8, 1994 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 - REQUEST FOR RELIEF FROM ARTICLE IWA-5250(a)(2)
OF THE 1986 EDITION AMERICAN SOCIETY OF MECHANICAL ENGINEERS (ASME)
SECTION XI INSERVZCE SYSTEM PRESSURE TEST CODE REQUIREMENTS FOR REACTOR RECIRCULATION VALVE 2-FCV-68-33 In accordance with the provisions of 10 CFR 50.4 and 10 CFR 50.55a(g)(5)(iii),
TVA is submitting a request for relief from the 1986 Edition of the ASME Boiler and Pressure Vessel
The 1986 Code requirements for leakage at a
bolted connection requires removal, inspection, and evaluation of all bolting at the pressure retaining component bolted connection.
By Reference 1,
TVA requested relief from the 1986 Edition of the ASME Boiler and Pressure Vessel Code IWA-5250(a)(2),
system pressure test requirements for reactor recirculation valve 2-FCV-68-33.
By Reference 2,
NRC provided their approval.
However, relief was only granted until the next refueling outage (Unit 2 Cycle 7).
For the BFN Unit 2 Cycle 7 refueling outage, TVA proposes to use the provisions of the 1992 Edition of the ASME Boiler and Pressure Vessel
- Code, IWA-5250(a)(2),
as an alternate method of testing.
The 1992 Code Edition requirement for bolted connections requires removal, inspection, and evaluation of one bolt in the area closest to the leakage.
When the removed bolt shows evidence of degradation all the remaining bolting is removed and inspected.
C 94071'st0440 940708 PDR ADOCK 05000260 I-PDR
4l Ci II
U.
S. Nuclear Regulatory Commission Page 2
July 8, 1994 10 CFR 50. 55a (g) (4) (iv) permits a licensee to meet the requirements set forth in subsequent ASME Section XI, Code Editions provided that the subsequent Code Editions are referenced in 10 CFR 50.55a(b).
The 1992 Edition of the ASME Boiler and Pressure Vessel Code recognizes removal and inspection of one bolt as an acceptable corrective action for a leaking mechanical joint.
Therefore, TVA considers that the proposed alternate provides a reasonable method to allow verification of reactor recirculation valve 2-FCV-68-33 stud integrity without any reduction in the level of quality or safety.
The ASME Section XZ, 1992 incorporated by reference TVA requests NRC approval on or before September 1,
Cycle 7 refueling outage.
Code Edition has not been in 10 CFR 50.55a(b).
Therefore, of the enclosed request for relief 1994, to support the BFN Unit 2 On May 24,
- 1994, TVA met with NRC to discuss BFN Unit 2 Cycle 7 refueling outage inservice inspection activities and reactor recirculation valve 2-FCV-68-33 proposed request for relief.
During this meeting, NRC requested TVA to address reactor recirculation valve 2-FCV-68-33 joint integrity and actions to be taken should leakage occur during BFN Unit 2 Cycle 7 refueling outage.
Enclosure 1 contains the proposed request for relief. Enclosure 2 contains TVA response to NRC's request.
There are no commitments contained in this letter.
Xf you have any questions contact me at extension (205)-729-2636.
Sincerel Pe r Salas Manager of Site Licensing Enclosure cc:
See page 3
I II
/
U.S. Nuclear Regulatory Commission Page 3
July 8, 1994 References 1 ~
2.
Letter from TVA to NRC, dated May 16 1993,.
"BFN Unit 2 American Society of Mechanical Engineers (ASME)Section XI Inservice,System Pressure Test Program Request.for Relief for Valve FCV-'8-33 Bonnet-To-Body Bolting" Letter from NRC to TVA, dated May 21, 1993',
"BFN Unit 2 Safety Evaluation of Requests for Relief From American Society of Mechanical Engineers Boiler and,.Pressure Vessel Code Requirements,(TAC NO.;M83581)"
U.S. Nuclear Regulatory Commission Page 4
July 8, 1994 Enclosure cc (Enclosure):
Mr. Mark S. Lesser, Section Chief U.S. Nuclear Regulatory Commission Region II 101 Marietta Street, NW, Suite 2900 Atlanta, Georgia 30323 NRC Resident Inspector Browns Ferry Nuclear Plant Route 12, Box 637
- Athens, Alabama 35611 Mr. J.
F. Williams, Project Manager U.S. Nuclear Regulatory Commission One White Flint, North 11555 Rockville Pike Rockville, Maryland 20852 Mr. D.
C. Trimble, Project Manager U.S. Nuclear Regulatory Commission One White Flint, North 11555 Rockville Pike Rockville, Maryland 20852
0 41
U.S. Nuclear Regulatory Commission Page 5
July 8, 1994 JEM:DEM MTN Enclosure cc (Enclosure):
E.
W. Huston, BR 4G-C R.
D. Machon, PAB 1E-BFN T. J.
W. Overlid, BR 4J-C E. Preston, POB 2C-BFN J.
R. Rupert, EDB 1A-BFN T. D. Shriver, PSB 1K-BFN
- 0. J.
J'i
ENCLOSURE 1
TENNESSEE VALLEY AUTHORXTY BROWNS FERRY NUCLEAR PLANT (BFN)
UNZT 2 AMERICAN SOCZETY OF MECHANICAL ENGINEERS (ASME)
SECTION ZZ SYSTEM PRESSURE TEST PROGRAM REQUEST FOR RELXEF SPT-7 I
PURPOSE
'This enclosure requests relief from the 1986 Edition of the American Society Of Mechanical Engineers (ASME) Boiler and Pressure Vessel
TVA proposes to use provisions of the 1992 Edition of the ASME Boiler and Pressure. Vessel
- Code, IWA-5250(a)(2), as an alternate method of testing.
ZZ ~
BACKGROUND TVA performed
- a. Code Class 1 leakage test following completion of BFN Unit 2 Cycle 6 refueling outage.
During this test, TVA identified leakage at.the bonnet-to-body bolted connection on reactor recirculation valve 2-FCV-68-33.
TVA was unsuccessful in removing the bonnet-to-body studs for th'e VT-3, visual examination.
These studs are 1-3/4 inch diameter, A540 Grade B23 material.
The valve body is A351 Grade CF8 material.
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.
Therefore, TVA submitted request for relief SPT-6 (Reference 1).
Request'or relief SPT-6 proposed as an alternate method to perform a visual test VT-1 examination with the studs in place, instead of the required ASME Section XI Code, 1986 Edition visual test VT-3 examination with the studs removed.
NRC approved TVA's alternate method described in request for relief SPT-6.
However, the approval was conditional.
NRC stated in Reference 2 that it was necessary to impose the Code requirements at the next refueling outage (Unit 2 Cycle 7).
Since the BFN Unit 2 Cycle 6 refueling outage, TVA purchased a new stud removal device, APEX Technologies, Inc., stud removal tool.
This tool is designed to grip the stud.as close as practical to the threaded housing holding the stud, resulting in minimal mechanical losses and no side loading.
The turning motion and an impact
from the driver (air-driven impact wrench) are uniformly delivered down the stud causing enough torque at the stud housing to break the stud loose..
TVA expects complete success in complying with the ASME Section XI Code, 1992 Edition, requirement (remove one stud) with the APEX Technologies Inc., stud removal device.
III DISCUSSION On May 24,
- 1994, TVA personnel met with NRC and discussed the-upcoming Unit 2 cycle 7 refueling outage Inservice Inspection activities.
TVA informed NRC of the current plans to submit a request for relief for valve 2-FCV 33.
This request for relief proposes an alternate to the requirement of the 1986 Edition of the ASME Boiler and Pressure Vessel
- Code, IWA-5250(a)(2).
IWA-5250(a)(2),
provides the corrective measures for leakage detected at a pressure retaining component bolted connection during a system pressure test.
IWA 5250(a)(2),
states that if leakage occurs at a bolted connection, the bolting shall be removed, visually examined for corrosion, and evaluated.
TVA proposes as 1992 Edition of IWA-5250(a)(2).
requirement for inspection, and to the leakage.
degradation all inspected.
an alternate method to comply with the the ASME Boiler and Pressure Vessel
- Code, IWA-5250(a)(2),
1992 Code Edition, bolted connections requires removal, evaluation of one bolt in the area closest When the removed bolt shows evidence of the remaining bolting is removed and El-2
.XV REFERENCES Letter from TVA to NRC, dated May 16, 1993,"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" 2.
Letter from NRC to TVA, dated May 21,
- 1993, "BFN Unit 2
Safety Evaluation Of Requests For Relief From American Society Of Mechanical Engineers Boiler and Pressure Vessel Code Requirements (TAC NO. M83581)"
E1-3
0
~astern:
Drawinc[:.
REQUEST FOR RELIEF SPT-7 (Unit 2)
Reactor Recirculation (68) 47E817-1 (FSAR Figure 4.3-2a Sheet 2)
Recirculation valve 2-FCV-68-33 bonnet-to-body studs Class:
'Function:
Im ractical Test Re uirement:
Pressure Retaining Bolting IWA-5250(a)'(2), of the 1986 Edition of the ASME Section XI Code The source of leakage detected during the conduct of a system pressure test shall be located.and evaluated by the owner for corrective measures.
>>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:
IWA-5250(a) (2),
1992 Edition of the ASME Boiler and Pressure Vessel
- Code, requires one bolt for reactor recirculation valve 2-FCV-68-33 to be removed and inspected for corrosion.
The bolt removed must be the one closest to the source of leakage.
- Whereas, ASME Boiler and Pressure Vessel
- Code, 1986 Edition requires removal and inspection of all 24 bolts.
IWA-5250(a) (2),
1992 Code Edition, recognizes that the bolts in the area of the process fluid leaking at a bolted connection are susceptible to corrosion due to the leak.
- However, this code edition "considers removal and inspection of one bolt closest to the leak as an adequate representation of the bolting that has been wetted by the leaking joint.
Reactor recirculation valve 2-FCV-68-33 cannot be isolated from the reactor vessel.
Should galling of the stud to valve body occur, it would be necessary to rethread the
Basis for Relief:
(Continued) valve body.
Rethreading of the valve body would require removal of the valve bonnet.
Removal of the valve bonnet would require plugging of the jet pumps.
The performance of this work would require approximately two weeks.
Alternate Testin The estimated radiation exposure of this work is approximately 15 man-rem.
This estimate is based on a crew of two men, a galling rate of 50
- percent, a stud removal rate of two hours per stud, 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 stud, and a radiation field of 40 mrem per hour.
Since the 1992 Edition of the ASME Boiler and Pressure Vessel Code recognizes removal and inspection, of one bolt as an acceptable corrective action for a leaking mechanical joint, TVA considers that the proposed alternate provides a
reasonable inspection to allow verification of valve 2-FCV-68-33 stud integrity without any reduction in the level of quality or safety.
TVA will take corrective actions per IWA-5250(a)(2),
1992 Edition of the ASME Boiler and Pressure Vessel Code.
IWA-5250(a)(2), states: "If leakage occurs at a bolted connection, one of the bolts shall be removed, VT-3
- examined, and evaluated in accordance with IWA-3100.
The bolt selected shall be the one closest to the source of leakage.
When the removed bolt has evidence of degradation, all remaining bolting in the connection shall be removed, VT-3 examined, and evaluated in accordance with IWA-3100 E1-5
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ENCLOSURE 2
TENNESSEE VALLEY AUTHORITY BROWNS FERRY NUCLEAR PLANT (BFN)
UNIT 2 TVA~S RESPONSE TO NRC~S MAY 24~
1994 INFORMATION REQUEST PERTAINING TO REACTOR RECIRCULATION VALVE 2-FCV-68-33 On May 24,
- 1994, TVA personnel met with NRC to discuss the Unit 2 Cycle 7 refueling outage inservice inspection activities and reactor recirculation valve 2-FCV-68-33.
During this meeting, NRC requested TVA to address the following items for valve 2-FCV-68-33 to aid in their review.
1.
NRC REQUEST Address the joint integrity for valve 2-FCV-68-33.
TVA RESPONSE The valve body is made of A351 CF8 (cast austenitic steel) with an austenitic stainless steel flexitallic gasket and A540 B23 studs.
No corrosion related deterioration is anticipated due to the boiling water reactor water chemistry (i.e., this is not a borated system).
This valve has been in service since commercial operation and has not been disassembled.
Over time, joint relaxation may have occurred on this valve.
Therefore, TVA actions for joint relaxation would be to tighten,
- loosen, and retighten the stud nuts.
These actions reestablish valve joint integrity.
2 ~
NRC REQUEST Describe the actions TVA would take should valve 2-FCV-68-33 leak during BFN Unit 2 Cycle 7 refueling outage.
TVA RESPONSE During BFN Unit 2 Cycle 6 refueling outage, TVA loosened and retightened valve 2-FCV-68-33 stud nuts.
The process of
- tighten, loosen, and retighten the stud nuts was successful in stopping the leak.
Should leaks occur during BFN Unit 2 Cycle 7, the process (tighten,
- loosen, and retighten) would be repeated.
In addition, the code required VT-3 examination would be performed.
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