ML20062J565
| ML20062J565 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry, Surry, North Anna, 05000000 |
| Issue date: | 07/30/1982 |
| From: | Leasburg R VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.) |
| To: | James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| References | |
| REF-SSINS-6820 358, IEB-82-02, IEB-82-2, NUDOCS 8208160402 | |
| Download: ML20062J565 (5) | |
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< ig(y pCOlOil VInOINIA ELucTnIC AND POWEn COWPANYA, QLCI Ricurwown,VzmonwrA 20261 j2[3 4 P3 2"
4 n.n.Lua.muno July 30, 1982 Vaca Pomosomwr NuctaAm Oramations Mr. James P. O'Reilly Serial No. 358 i
Regional Administrator N0/RMT:acm U. S. Nuclear Regulatory Commission Docket Nos. 50-280 Region II 50-281 101 Marietta Street, Suite 3100 50-338 Atlanta, Georgia 30303 50-339 License Nos. DPR-32 DPR-37 NPF-4 I
NPF-7 l
Dear Sir:
RESPONSE TO IE BULLETIN 82-02:
DEGRADATION OF THREADED FASTENERS IN THE REACTOR COOLANT PRESSURE BOUNDARY OF PWR PLWTS As set forth in Action Item number five of the subject bulletin dated June 2, 1982, we are hereby providing the enclosed responses for our Surry and North Anna Power Stations.
Pursuant to Section 182a, Atomic Energy Act of 1954 as amended,-the information contained in the attached pages is true and accurate to the best cf my knowledge and belief.
Vcry truly yours, 3rh l
R. H Leasburg Enclosures (2) b cc:
Mr. R. C. DeYoung, Director Office of Inspection and Enforcement Washington, D. C. 20555 4
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i 8208160402 820730 jQ(
PDR ADOCK 05000280 O
Enclo:ura 1 to 358 NORTH ANNA POWER STATION UNIT NOS. 1 AND 2 IEB 82-02 ITEM 3 INFORMATION SUBMITTAL DEGRADATION OF THREADED FASTENERS IN THE REACTOR COOLANT PRESSURE BOUNDARY OF PWR PLANTS The following information is being submitted as requested by IEB 82-02, Item 3:
A.
RCPB bolted connections that have experienced leakage:
1.
Unit 2 Pressurizer Manway - Attributed to gasket failure. Cleaned mating surfaces and replaced gasket.
2.
Unit 1 Reactor Coolant System B Loop Stop Valve - Gasket failure resulting in boric acid corrosion of the carbon steel closure studs.
All Unit I loop stop valve closure studs were examined.
There were 12 of 24 studs replaced on the IB loop stop valve.
3.
Unit 2 Safety Injection Header to RCS - Motor Operated Valves 2890A, B, C and D all experienced leakage through the body to bonnet connection due to gasket leakage.
In addition, the resulting concentration of boric acid caused corrosion of the body to bonnet studs.
4.
Residual Heat Removal System Motor Operated Valvec (a) Unit 1 MOV-1700 - Body to bonnet leakage currently under investigation.
(b) Unit 2 MOV-2720A - Body to bonnet leakage attributed to gasket failure. Mating surfaces were cleaned and the gasket replaced.
5.
Safety Injection System Check Valves (a) Unit 1; 1-SI-86, 1-SI-95 body to bonnet leakage currently under investigation.
(b) Unit 2; 2-SI-92, 2-SI-100 body to bonnet leakage due to gasket leakage. Mating surfaces were cleaned and the gasker, replaced.
6.
There were no instances of stress corrosion cracking in RCPB bolting material experienced at North Anna Units 1 or 2.
7.
The instances of gasket failure appear to have been caused by a decrease in stud loading of the bolted connection through its thermal cycling.
Although these operations were performed using approved procedures, the initial torque value seems to be insufficient to maintain long term integrity of the connection through the thermal cycles produced.
It appears that a retorque of the connections after the studs have stretched may be required in some cases. This subject was discussed specifically related to the RCP main flange bolt stretch by Westinghouse NSD Data Letter 82-03.
Enclosura 1 to 358
. B.
The Use of Lubricants and Injection Sealants 1.
The following lubricants have been approved for use on RCPB bolted connections.
a.
FEL-PRO N5000 b.
NEVER SEEZ - PURE NICKEL - (Nuclear Grade) c.
NE0 LUBE 100 The composition of these materials is proprietary.
2.
A previously approved lubricant FEL-PRO CSA has been recently disapproved for use in nuclear operations.
A memorandum to this effect was issued by Westinghouse on April 2, 1982. All Maintenance procedures that referenced the use of this material have been revised to specify the use of another approved lubricant.
3.
There have been no failures of bolted connections attributed to the use of these materials.
4.
The injection sealant (trade name - furmanite) is a non-adheasive thermosetting compound with high shear strength.
The composition of this material includes amounts of chlorine, fluorine, lead and i
sulphur as the most important stress corrosion cracking contaminants.
In each case, the leachable contaminants are documented by a Material Certification by an independent testing laboratory to be less than the maximum limit specified by the FURMANITE specification for nuclear grade material.
l 5.
Furmanite has been used in RCPB components; but, in all cases these connections are less than 6" diameter.
In each case, a written safety analysis was performed and the potential leachability of p
halogens determined.
It has been determined, in some instances, that l
the halogen concentration limit may be exceeded.
Therefore, the use l
of FURMANITE in the RCS has been restricted to emergency use only.
If used, the component will be replaced within 90 days.
This is based on the minor amounts of halogens observed in the initial 90 days after injection. Ref: General Electric Bulletin 81-831, 6.
In order to validate the basis of the specification for maximum contaminant levels in FURMANITE and the acceptability of using this inj ection sealant, a valve (1-RC-132) that had been injected with FURMANITE, was removed in a subsequent outage and sent to an l
independent laboratory for examination.
There was no evidence of corrosion induced by the FURMANITE.
The total time spent responding to this Bulletin was 30 manhours.
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Encloture 2 to 358 SURRY POWER STATION UNITS NOS. 1 AND 2 IEB 82-02 11EM 3 INFORMATION SUBMITTAL DEGRADATION OF THREADED FASTENERS IN THE REACTOR COOLANT PRESSURE BOUNDARY OF PWR PLANTS In response to I. E. Bulletin No. 82-02, Degradation of Threaded Fasteners in the Reactor Coolant Pressure Boundary of Power Plants, a list of RCPB components (See Attachment 1) has been compiled and procedures rewritten to ensure NDT Inspection of bolting material, and correct lubrication used.
1.
Steps do exist in the pertinent procedures, describing disassembly, reassembly, torquing sequences, torquing values, and lubrication to be used.
The only lubricant to be used on RCPB fasteners is now Felpro-N5000 as per Westinghouse Nuclear Service Division Letter, DL-82-01.
All procedures have been changed to define the correct lubricant.
(Felpro-N5000)
Injection sealant (i.e. Furmanite) has not been cllowed on any part of the RC System, so no known problem exists in this area.
2.
All procedures relating to RCPB's have been rewritten to incorporate a step for NDT Inspection of bolting material when opened for inspection or maintenance (See Attachment 2 to this enclosure).
The valve in general procedure MMP-C-G-001, which is not specific to any valve has a new addendum attached, listing all RCPB valves, and a new step written into i
the procedure refe: ring the individual perfoming the maintenance to this i
list to verify if the valve being worked requires NDT Inspection.
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3a.
Only two (2) major :omponente have suffered leakage due to bolting and L
material degradation.
This degradation being caused by the introduction of boric acid to the outer surfaces of the fastener.
(i) Unit 1 "C" Reactor Coolant Pump (1-RC-P-1C) Date: 09-26-81 Results:
l Boric acid buildup found between casing flange and pump flange.
The l
boric acid crystals were removed, and slight leakage between flanges i
l was located.
Further investigation showed degradation of some bolts.
l All bolts were removed. Bolts and bolts' holes were inspected by the NDT Department, resulting in six (6) bolts bei:.g replaced.
l Inspections were also carried out on 1-RC-P-1A and 1-RC-P-1B main j
flange bolting and found to be in satisfactory condition.
l (ii) Unit 2 MOV-RH-2700 Due to an excessive packing gland leak, boric l
acid had builtup around the bonnet studs and crystalized. Boric acid l
was removed and severe stud wastage was revealed.
All studs were l
replaced at this time, approximately 11-26-81.
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Enclorura 2 to 358,
3b.
The following lubricants for fasteners have been used on all RCPB components taken apart for inspection and/or repair:
Felpro-N1000, Felpro-N5000 except for the reactor head bolts and associated reactor fasteners where Neolube 100 was utilized.
Injection scalants have not been used on any of the RCP boundary components.
The evidence of Stress Corrosion Cracking has been identified and current procedures allow only the use of Felpro-N5000 on safety related fasteners, e
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