ML20058H700
| ML20058H700 | |
| Person / Time | |
|---|---|
| Site: | Calvert Cliffs  |
| Issue date: | 07/30/1982 |
| From: | Lundvall A BALTIMORE GAS & ELECTRIC CO. |
| To: | Haynes R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| References | |
| REF-SSINS-6820 IEB-82-02, IEB-82-2, NUDOCS 8208090049 | |
| Download: ML20058H700 (18) | |
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BALTIMORE GAS AND ELECTRIC CHARLES CENTER P.O. BOX 1475 BALTIMORE, MARYLAND 21203 ARTHUR E. LUNDVALL, JR.
vice PacsaDENT su w July 30,1982 U.S. Nuclear Regulatory Commission Region 1 631 Park Avenue King of Prussia, PA 19406 ATTENTION:
Mr. Ronald C. Haynes Regional Administrator
SUBJECT:
Calvert Cliffs Nuclear Power Plant Unit Nos.1 & 2; Docket Nos.53-317 & 50-318 IE Bulletin 82-02: Degradation of Threaded Fasteners in the Reactor Coolant Pressure Boundary of PWR Plants Gentlemen:
The purpose of this letter is to provide the information requested by Action item 3 of the subject bulletin. Enclosure (1) to this letter summarizes our experience with leakage of bolted closures in the reactor coolant pressure boundary (RCPB) as defined by IE Bulletin 82-02. Enclosure (2) provides the chemical compositions of the lubricants utilized on RCPB bolted closures.
Injection sealant materials have never been used on bolted closures in the RCPB.
Appproximately 155 manhours were expended preparing this response.
Should you have further questions regarding this reply, we will be pleased to discuss them with you.
Very truly yours, b
as
.'H. Miller for A. E. Lundvall, Jr.
Vice President - Supply AEL/RT3/gla Enclosures cc:
- 3. A. Biddison, Esquire G. F. Trowbridge, Esquire D. H. Jaffe, NRC R. E. Architzel, NRC 9208090049 820730
[Il PDR ADOCK 05000317 G
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O Mr. R. C.'Haynes July 30,1982 Page 2 STATE OF MARYLAND :
TO WIT:
CITY OF BALTIMORE Henry H. Miller being duly sworn states that he is Vice President of the Baltimore Gas and Electric Company, a corporation of the State of-Maryland; that he provides the foregoing response for the purposes therein set forth; that the statements made are true and correct to - the best of his knowledge, information, and belief; and that he was authorized to provide the response on behalf of said Corporation.
WITNESS my hand and Notarial Seal:
_Af/IU MALO Notary Public My Commission Expires:
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ENCLOSURE (1)
RCPB BOLTED CLOSURE LEAKAGE EXPERIENCE Unit Date Component Unit 1 April 1974 Reactor Vessel Closure Studs Technical Data Stud Dimensions:
7" - 8 UN x 561/4" Stud Material:
ASTM A-540 GR.B24 CL.3 Phosphate coated Lubricant:
SuperMoly 4064 diluted with toluene Gasket Material:
"O" ring seals, Inconel 718 Event Summary Minor boric acid corrosion of the studs was discovered following hot functional testing.
The corrosion was attributed to leakage of primary borated water from temporary closure flanges on three of eight instrument penetrations on the reactor vessel head. All of these temporary instrument closure flanges were immediately replaced with the permanent instrument closure flanges. Microexamination of studs exposed to the leakage revealed some etching in the shank area described as shallow, round bottomed grooves having maximum depths of 0.003". No additional corrective actions were required due to the minor extent of the stud damage and the temporary nature of this type of instrument 1
closure flange. There has been no evidence of stud corrosion since this event.
RCPB BOLTED CLOSURE LEAKAGE EXPERIENCE Unit Date Component Unit 2 October 1977 2-SI-215; 12" Atwood and Morrill Swing Check Valve Technical Data
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Bearing Cover Stud Dimensions:
7/8"-9UNC x 3" (fully threaded)
Bearing Cover Stud Material:
ASTM A-453 GR. 66 Chrome-plated threads Lubricant:
FelPro N-5000 Bearing Cover Gasket Material:
Flexitallic Type 304 S.S. and abestos,200 ppm Cl maximum 4
Event Summary During the October 1977 Maintenance Outage, leakage from the hinge pin bearing cover of 2-51-215 was discovered. The bearing cover was removed and the cover gasket was replaced. There was no evidence of stud corrosion.
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, RCPB BOLTED CLOSURE LEAKAGE EXPERIENCE Unit Date Component Unit 1 February 1978 1-SI-148; 6" Velan Balanced Swing Check Valve Technical Data Cover Stud Dimensions:
11/4 - 8 UNC x 4 3/4 Cover Stud Material:
ASTM A-193 GR.B7 Phospnate coated Lubricant:
FelPro N-5000 Cover Gasket Material:
Flexitallic Type 316 S.S and Balance Arm Packing Material:
John Crane 187-I; Inconel wire insert wrapped with asbestos yarn around a core of asbestos impregnated with graphite Event Summary During the January 1978 Refueling Outage, leakage from the cover and balance arm -
stuffing box of 1-SI-148 was discovered. Further investigation revealed a small, damaged area on the cover gasket and a loose packing gland on the balance arm to be the causes of the leakage. The cover gasket was replaced, the balance arm stuffing box was repacked, and the packing gland was tightened. There was no evidence of stud corrosion.
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_4-RCPB BOLTED CLOSURE LEAKAGE EXPERIENCE Unit Date Compenent Unit 2 October 1979 2-51-215; 12" Atwood & Morrill Swing Check Valve Technical Data Bearing Cover Stud Dimensions:
7/8"-9UNC x 3"(fully threaded)
Bearing Cover Stud Material:
ASTM A-453 GR. 66 Chrome-plated threads Lubricant:
FelPro N-5000 Bearing Cover Gasket Material:
Flexitallic Type 304 S.S. and abestos,200 ppm Cl maximum Event Summary During the October 1979 Ref ueling Outage, leakage from the hinge pin bearing cover of 2-SI-215 was discovered. The bearing cover was removed and the cover gasket was replaced. There was no evidence of stud corrosion.
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- RCPB BOLTED CLOSURE LEAKAGE EXPERIENCE Unit Date Component Unit 1 November 1980 1-SI-215; 12" Atwood & Morrill Swing Check Valve Technical Date Bearing Cover Stud Dimensions:
7/8"-9UNC x 3" (fully threaded)
Bearing Cover Stud Materials:
ASTM A-453 GR. 66 Chrome-plated threads Lubricant:
FelPro N-5000 Bearing Cover Gasket Material:
Flexitallic Type 304 S.S. and abestos, 200 ppm Cl maximum Event Summary During the November 1980 Ref ueling Gotage, leakage from the hinge pin bearing covers of 1-SI-215 was discovered. The bearing covers were removed and the cover gaskets were replaced. There was no evidence of stud corrosion.
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V V RCPB BOLTED CLOSURE LEAKAGE EXPERIENCE Unit Date Component Unit i November 1980
- 12 A Reactor Coolant Pump Studs
- 11 B Reactor Coolant Pump Studs Technical Data Stud Dimensions:
4 3/4" - 8UN x 34" Stud Material:
ASTM A-540 GR.B23 CL.4 Phosphate coated shank Flash chrome-plated threads Lubricant:
Neolube Gasket Material:
Flexitallic Type 304 S.S. and asbestos,200 ppm C1 maximum Event Summary Following the issuance of NRC Information Notice Number 80-27, a visual inspection of the Unit 1 Reactor Coolant Pump (RCP) studs was scheduled for the next refueling outage. This inspection disclosed fourteen studs on #11 B RCP with indications and thirteen studs on #12A RCP with indications. Since Appendix A to ASME Code Section XI 1974 Edition with Addenda through Summer 1975 was not applicable to the evaluation of flaws found in the RCP studs, Byron Jackson was retained to perform an analysis to develop an acceptance criteria for them. Eight studs on #11B RCP and five studs on
- 12A RCP did not meet the criteria established by Byron Jackson's preliminary calculations. However, all of the studs with indications were replaced as a precautionary measure. Following this event, Combustion Engineering was retained to perform a destructive examination of one of the corroded RCP studs. The examination program included.
1.
Visual examination /macrophotography 2.
Brinnell hardness measurements 3.
X-ray diffraction analyses of oxide samples 4.
Scanning electron microscope - wave length dispersive spectrometer analyses of oxide samples for boron content.
The results of these examinations indicated that boric acid corrosion was resonsible for the metalloss discovered in the RCP studs.
The Unit 1 RCPs showed no signs of gasket failure between the pump case and driver mount. The cause of stud corrosion is believed to be a combination of RCP insturment line failures, poor control of reactor coolant during venting operations, and instrument line valve packing leakage. Improved pump venting techniques, stricter housekeeping requirements, and real line modifications were implemented and are expected to eliminate the stud deterioration problem.
During the recent April 1982 Refueling Outage, minor corrosion of a nut on one stud in
- 11A RCP was discovered. In this instance, the top of the nut had corroded to a maximum depth of 0.375" in one area. The nut was replaced as a precautionary measure. No further indications of RCP stud corrosion were discovered.
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- RCPB BOLTED CLOSURE LEAKAGE EXPERIENCE Unit Date Component Unit 1 November 1980
- 11 Steam Generator Primary Manway Studs Technical Data Stud Dimensions:
1 1/2"- 8 UN x 101/2" Stud Material:
ASTM A-540 GR.B24 CL.3 Phosphate coated Lubricant:
Neolube Gasket Material:
Flexitallic Type 304 S.S. and asbestos,200 ppm C1 maximum Event Summary During the October 1980 Refueling Outage, while preparing for steam generator eddy current examinations, minor corrosion of the primary manway cover studs was discovered. Those studs with evidence of corrosion were replaced and two of the corroded studs were forwarded to Combustion Engineering for destructive examination by the same methods outlined on page six for the RCP studs. Detailed examination was deemed desirable because of the cracking that had occurred in similar studs at other PWRs. The results of these examinations indicated tha the corrosion products formed on the primary manway studs was typical of the oxides formed on alloy steels exposed to low temperature water environments. The corrosion was attributed to primary water weeping past the manway gaskets. No evidence of cracking was discovered. No indications of steam generator primary manway stud corrosion were discovered during the April 1982 Unit 1 Refueling Outage.
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RCPB BOL,TED CLOSURE LEAKAGE EXPERIENCE Unit Date Component Unit 2 January 1981
- 22A Reactor Coolant Pump Studs
- 22B Reactor Coolant Pump Studs Technical Data Stud Dimensions:
4 3/4" - 8UN x 34" Stud Material:
ASTM A-540 GR.B23 CL.4 Phosphate coated shank Flash chrome-plated threads Lubricant:
Neolube Gasket Material:
Flexitallic Type 304 S.S. and asbestos,200 ppm C1 maximum Event Summary A visual inspection of the Unit 2 RCP studs was performed during the January 1981 Refueling Outage. This inspection disclosed four studs on #22 A RCP with indications and eight studs on #22B RCP with indications. As a precautionary measure, all of the studs with indications were replaced. The corrosion mechanism and corrective actions described on page six of this enclosure are equally applicable to this event.
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. RCPB BOLTED CLOSURE LEAKAGE EXPERIENCE Unit Date Component Unit 2 January 1981 Pressurizer Manway Studs Technical Data Stud Dimensions:
1 1/2"- 8 UN x 101/2" Stud Material:
ASTM A-540 GR.B24 CL.3 Phosphate coated Lubricant:
Neolube Gasket Material:
Flexitallic Type 304 S.S. and asbestos,200 ppm Cl maximum Event Summary In August 1980, minor leakage from the pressurizer manway was discovered. An early attempt to retorque the manway cover bolts f ailed to eliminate the leakage and further corrective action was deferred until the January 1981 Refueling Outage. At that time the manway cover was removed and the closure surface and cover were inspected for steam cuts. Visual inspection revealed minor erosion of the closure surface and cover to a maximum depth of one sixteenth of an inch near two of the closure studs. As a precautionary measure, these studs were replaced. No additional corrective actions were required due to the minor extent of the damage.
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b RCPB BOLTED CLOSURE LEAKAGE EXPERIENCE Unit Date Component Unit 2 January 1981 2-51-217; 12" Velan Swing Check Valve Technical Data Cover Stud Dimensions:
17/8"-8UN x 31/4" Cover Stud Material:
ASTM A-193 GR.B7 Phosphaste coated Lubricant:
FelProN-1000 Cover Gasket Material:
Flexitallic Type 316 S.S and asbestos, 200 ppm Cl maximum Event Summary During the January 1981 Refueling Outage, leakage from the cover of 2-51-217 was discovered. Subsequent investigation revealed that the cover gasket did not have any asbestos lef t in it and significant boric acid corrosion of the studs had occurred. All sixteen cover studs were replaced and a new cover gasket was installed.
Following this event, all of the valves in the Unit 2 RCPB were examined for evidence of leakage and subsequent corrosion of their threaded fasteners. Further, all of the valves in the Unit 1 RCPB were examined during the April 1981 Maintenance Outage. No
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further instances of boric acid corrosion of threaded fasteners were revealed during these examinations.
Although IE Bulletin 82-02 had not been issued as of this date, our definition of the RCPB l
(for the purpose of performing the examinations above) was the same as the definition l
provided in that bulletin.
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/ RCPB BOLTED CLOSURE LEAKAGE EXPERIENCE Unit Date Component Unit 2 January 1981 2-SI-237; 12" Velan Swing Check Valve Technical Data Cover Stud Dimensions:
17/8"-8UN x 31/4" Cover Stud Material:
ASTM A-193 GR.B7 Phosphate coated Lubricant:
FelProN-1000 Cover Gasket Material:
Flexitallic Type 316 S.S.
and asbestos,200 ppm Cl maximum Event Summary During the January 1981 Refueling Outage, leakage from the cover of 2-51-237 was discovered. The cover was removed and the cover gasket was replaced. There was no evidence of stud corrosion.
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~ RCPB BOLTED CLOSURE LEAKAGE EXPERIENCE
. Unit Date Component Unit 2 January 1981 2-SI-245; 12" Atwood & Morrill Swing Check Valve Technical Data Bearing Cover Stud Dimensions:
7/8"-9UNC x 3" (fully threaded)
Bearing Cover Stud Material:
ASTM A-453 GR. 66 Chrome-plated threads Lubricant:
FedPro N-5000 Bearing Cover Gasket Material:
Flexitallic Type 304 S.S. and abestos,200 ppm Cl maximum Event Summary During the January 1981 Refueling Outage, leakage from the hinge pin bearing cover of 2-51-245 was discovered. The bearing cover was removed and the cover gasket was replaced. There was no evidence of stud corrosion.
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RCPB BOLTED CLOSURE LEAKAGE EXPERIENCE l
Unit Date Component -
i Unit 2 January 1981 2-51-215; 12" Atwood & Morrill Swing Check Valve i
Techncial Data i
Bearing Cover Stud Dimensions:
7/8"-9UNC x 3" (fully threaded)
Bearing Cover Stud Material:
- ASTM A-453 GR. 66 Chrome-plated threads Lubricant:
FelPro N-5000 Bearing Cover Gasket Material:
Flexitallic Type 304 S.S. and abestos,200 ppm Cl maximum Event Summary During the January 1981 Refueling Outage, leakage from the hinge pin bearing cover of 2-SI-215 was discovered. The bearing cover was removed and the cover gasket was replaced. There was no evidence of stud corrosion.
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, RCPB BOLTED CLOSURE LEAKAGE EXPERIENCE Unit Date Component Unit 2 January 1981 2-S1-148; SI Velan Balanced Swing Check Valve Technical Data Cover Stud Dimensions:
5.1/4 - 8UNC x 4 3/4 Cover Stud Material:
ASTM A-193 GR.B7 Phosphate coated Lubricant:
FelPro N-5000 Cover Gasket Material:
Flexitallic Type 316 S.S. and asbestos,200 ppm Cl maximum Balance Arm Packing Material:
John Crane 187-I; inconel wire insert wrapped with abestos yarn around a core of asbestos impregnated with graphite Event Summary i
During the January 1981 Refueling Outage, leakage from the cover and balance arm stuffing box of 2-51-148 was discovered. The cover gasket was replaced and the balance arm stuffing box was repacked. There was no evidence of stud corrosion.
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ENCLOSURE (2)
LUBRICANT UTILIZATION AND CHEMICAL COMPOSITION LUBRICANT UTILIZATION Components Lubricant Reactor Vessel Closure Studs Super Moly 4064 diluted with toluene Steam Generator Primary Manway Studs Pressurizer Manway Studs Neolube Reactor Coolant Pump Studs Valve Closure Studs:
a.
12" Atwood & Morrill Swing Check Valves SI-215,225,235,245 FelPro N-1000 or b.
12" Velan Swing Check Valves FelPro N-5000*
SI-217,~ 227, 237, 247
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c.
12" Velan Gate Valves51-614, 624, 634, 644, 651, 652 d.
6" Velan Balanced Swing Check Valves S1-118, 128, 138, 148
- FelPro N-3000 preferred due to lower copper content.
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2-LUBRICANT UTILIZATION AND CHEMICAL COMPOSITION LUBRICANT COMPOSITION SuperMoly 4064:
Molybdenum disulfide in mineral oil.
i Neolube:
Graphite in isopropanol - a thermoplastic resin.
Impurities by specification (parts per million)
Chlorine 200 Lead 150 Fluorine 20 Sulfur 200 FelPro N-1000:
Copper and graphite in silicone oil.
Impurities by lot (parts per million)
Cadm;um 3
Sulfur 25 Chlorine 20 Tin 18 Lead 4.5 Zinc 90 Mercury 0.04 FelPro N-5000:
Nickel and graphite in silicone oil.
3 Impurities by lot (parts per million)
Cadmium 0.6 Mercury 0.21 Chlorine 20 Sulfur 25 Copper 1.6 Tin 7
Flourine 15 Zinc 1.1 i
Lead 7.2 i
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