ML20148E526
| ML20148E526 | |
| Person / Time | |
|---|---|
| Site: | LaSalle  |
| Issue date: | 01/18/1988 |
| From: | Butterfield L COMMONWEALTH EDISON CO. |
| To: | Davis A NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| References | |
| 1787K, 4099K, CAL-RIII-87-26, NUDOCS 8801260053 | |
| Download: ML20148E526 (8) | |
Text
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/'] One Fir t NItional Plaza Chicago lihnois Q
Commonwealth Edison
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O Address Reply to: Post Offc) Box 767 Chicago, Illinois 60690 0767
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Mr. A. Bert Davis it /p,D/f Regional Administrator U.S. Nuclear Regulatory Commission Region III 799 Roosevelt Road Glen Ellyn, IL 60137
Subject:
LaSclle County Station Units 1 and 2 Response to Confirmatory Action Letter Regarding the LaSalle Unit 1 Main Steam Isolation Valve (MSIV) Failure on December 17, 1987 NRC Docket Nos. 50-373 and 50-374 References (a):
A.B. Davis letter to Cordell Reed dated December 18, 1987 (b):
G.J. Diederich letter to M.J. Jordan dated January 15, 1988, discussing Testing MSIV's at LaSalle
Dear Mr. Davis:
The referei.ced letter trar.smitted tne NRC Confirmatory Action Letter (CAL) regarding the lesalle Unit 1 Main Steam Line Isolation valve (MSIV) failure on December 17, 1987. The CAL stated that certain specified actions would be performed by Commonwealth Edison.
The enclosure provides a description of the ac
,)ns tekon and the results obtained from each of the CAL items.
Please direct any additional questions regarding this matter to this office.
Very truly yours L. D. Butterfield Nuclear Licensing Manager 1m (Q
VAclosure 4
cc: Region III Inspector - LSCS JN12 0 d f[
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ENCLOSURE
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V 1.
Replac9 the remaining solenoid valve assemblies _on Unit 1 (the failed MSIV solenvid has been replaced).
The remaining solenoid valvo assemblies on Unit I were replaced on December 18, 1987, and satisfactority testing on December 19, 1987.
2.
perform an initial evaluation of the_ quality (i.e., moisture, oil t
particulates) of the air system supplying the failed valve and the__ valves wnose solenoid assemblies are being replaced by sampilnq the immediate supply to the solenoid assemblies.
An initial evaluation of the quality of the air system supplying each of the Unit 1 MSIV's was performed on December 18, 1987. This was accomplished by disconnecting the air supply line for each valve and blowing air through a white filter medium.
No presence of moirture or hydrocarbons was detected. Metallic particles were found in the intial sample which were attributed to breaking / making the piping connections.
No contaminants were detacted which could have caused the solenoid valve assembly failure.
A\\s l 3.
Perform increased frequency testing of the MSIV's on Unit 1 as described _
in LaSalle Station letter to M.J. Jorday__ dated December 18, 1987.
The testing frequency has been revised as the result of our investigations.
The current testing program is described in a letter from G.J. Diederich to M.J. Jcrdan dated January 15, 1988.
This letter is included as Appendix I.
This increased frequency test program will also be applied to Unit 2.
Tests were successfully performed on December 19 and 26, 1987 and on January 2, and 9, 1988, as outlined in the referenced letter.
4.
Perform further analysis of the quality of the air nystem for the purpose of detecting contaminants which may degrade the solenoid assemblies.
Samples of the air supplied to each MSIV were obtained by the Commonwealth Edison Station Materials Analysis Department (SMAD) on December 18, 1987 These samples were analyzed for moisture content and hydrocarbons. The results indicated a maximum condensed hydrocarbon content of 1.3 mg/m3 and a dew point rar.ging from -41*F to -70*F.
No contaminants were detected which could have caused the solenoid valve assembly failure.
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N 5.
Disassemble the removed valves and examine them for potential causes which could lead to failures similar to the one experienced.
Four of these valves may be disassembled by the vendor (Asco) at the vendor's location.
The purpose of the examination is to determine a root cause for the failure.
In addition to the failed valve, one outboard and two inboard MSIV solenoid valve assemblies.were disassembled and inspected by LaSalle Station personnel on December 18, 1987.
The remaining two inboard and two outboard MSIV solenoid valves were
~ disassembled and inspected by the vendor (ASCO) at the vendor's facilities on December 21 and 22, 1987. The failed valve was also inspected by ASCO at their facilities.
The results of the above inspections are described in Appendix II.
6.
Perform a test of the dual solenoid valves on the Unit 2 MSIV's to.
determine if a similar problem exists on Unit 2.
The Unit 2 MSIV solenoid valve assemblies were satisfactorily tested on December 19, 1987.
7.
Submit to NRC Region III a formal report of your findings and conclusions within 30 days of receipt ot this letter.
The pilot solenoid valve associated with MSIV IB21-F028C failed to change state when being de-energized because of a thin film between the core assembly and plu;-nut, which acted as an adhesive, preventing the core-assembly from moving.
It is our opinion that.the source of this thin film is the Dow 550 lubricating fluid which is applied by ASCO to the interface of the core assembly and plug-nut of the NP8323 solenoid valve with AC coils. The rate at which the Dow 550 degrades is exponentially related to the temperature which it is exposed.
Discussion with ASCO supported the recommendations of ASCO Bulletin 8323 which states:
"While in service, operate the valve periodically to insure proper opening and closing."-
'rherefore, a conservative cycling. test frequency of once every three months for a period of six raonths followed by monthly tests will be performed for both Units 1 and 2.
This surveillance is discussed in more detail in Reference (b).
O 4099K
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O CONFIRMATORY ACTION LETTER
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DEC 21 1997 CAL-RIII-87-026 Docket No. 50-373 Docket No. 50-374 Commonwealth Edison Company ATTN: Mr. Cordell Reed Senior Vice President Post Office Box 767 Chicago, IL 60690 Gentlemen:
This letter confirms the telephone conversation between C. E. Norelius of this office and D. Galle of 18, 1987, related to the Main Steam Isolation Valve (your staff on DecemberMSIV) failure (one outboard MSIV fa shut) occurring at LaSalle Unit 1 on December 16, 1987. With regard to this event, we understand that you will:
1.
Replace the remaining solenoid valve assemblies on Unit 1 (the failed MSIV solenoid has been replaced).
2.
Perform an initial evaluation of the quality (i.e., moisture, oil,
)
particulates) of the air system supplying the failed valve and the valves 1
whose solenoid assemblies are being replaced by sampling the immediate supply to the solencid assemblies.
3.
Perform increased frequency testing of the MSIVs on Unit 1 as described in a LaSalle Station letter to M. Jordan dated December 18, 1987, i
4.
Perform further analysis of the quality of the air system for the purpose of detecting contaminants which may degrade the solenoid assemblies.
5.
Disassemble the removed valves and enmine them for potential causes which could lead to failures similar to the one experienced.
Four of these valves may be disassembled by the vendor (ASCO) at the vendor's location. The purpose of the examination is to detennine a root cause for the failure.
6.
Perform a test of the dual solenoid valves on the Unit 2 MSIVs to determine if a similar problem exists on Unit 2.
7.
Submit to NRC Region III a formal report of your findings and conclusions within 30 days of receipt of this letter.
Throughout this investigative effort, we understand that you will take those actions necessary to ensure that complete documentary evidence of the "as found" condition of equipment being inspected is maintained, gd CONFIRMATORY ACTION LETTER
C0hf!RMATORY ACTION LETTER DEC 1 1987 Comonwealth Edison Company 2
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We understand that actions 1 and 2 will be accomplished prior to startup of Unit 1 and that startup of Unit I will not occur without concurrence of the Regional Administrator or his designee.
Items 3 thru 6 should be a p aed promptly with item 6 being completed within 3 days of the date of this letter.
Further, we understand that you will promptly notify the NRC of any finding relative to these actions or the performance of the MSIVs.
Issuance of this Confinnatory Action Letter does not preclude the issuance of an order requiring implementation of the above commitments.
None of these actions should be construed to take precedence over actions which you feel necessary to ensure plant and personnel safety.
Please let us know immediately if your understanding differs from that set out above.
Sincerely, n
fs A. B. Davis Q
Regional Administrator cc:
D. Butterfield, Nuclear Licensing Manager G. J. Diederich, Plant Manager DCD/DCB (RIDS)
Licensing Fee Management Branch Resident Inspector, RIII Richard Hubbard J. W. McCaffrey, Chief, Public Utilities Division David Rosenblatt, Governor's Office of Consumer Services E. L. Jordan, AE00 J. M. Taylor, DEDO T. E. Murley, NRR J. Lieberman, OE R. Cooper, EDO W. Lanning, NRR F. Miraglia, NRR G. Holahan, NRR i
D. Crutchfield, NRR J. Partlow, NRR M. Jordan, SRI O
J. Strasma, RIII R. Lanksbury, RIII J. Goldberg, 0GC CONFIRMATORY ACTION LETTER
SARGENT & LUNDY ENGINEER $
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APPENDIX I O
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O January 15, 1988 TO:
Mr. M. J. Jordan
SUBJECT:
Testing of Main Steam Isolation Valves (MSIV's) on !iSalle County Station Units 1 and 2 REFER ENCE : Letter from R. D. Bishop to M. J. Jordan Dated December 18, 1987 This letter supercedes the testing comr.it.nents described in the ceferenced letter.
Based on our investigation, the mechanism which caused the failure of the MSIV on December 17, 1987, is time dependent and random in nature. Available data indicates that the solenoid valve assemblies will function properly for a minimum of six months of unit operation prior to failure.
The above information, along with the satisfactory tests completed to date, has resulted in the Boiling Water Reactor Engineering Department (BWR-B)
('g recommending a revision to the MSIV test frequency described in the referenced
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letter.
The revised testing schedule is as follows; 1.
Test the valves quarterly during the first six months of unit operation following replacement.
2.
After the first six months of unit operation following replacement, test the valves monthly.
3.
The scheduled testing will therefore proceed as follows:
a.
For Unit 1, the valves will be tested before or during the second refueling outage or prior to April 2, 1988, if the outage is postponed. The Unit 1 outboard valves were last tested January 9, 1988 and the inboard valves were last tested January 2, 1988.
b.
For Unit 2, the valves will be tested monthly until the second refueli.ng outage or until replaced.
4.
The above test frequencies will be subject to the normal Technical Specification allowance of section 4.0.2.
5.
Our plans are to replace the solenoid valve assemblies on both units during their respective second refueling outages.
Anytime the valves are ceplaced, the testing frequency will be returned to quartarly for the first six months of unit operation and monthly thereafter.
DOCUMENT ID 1787k
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Testing of the MSIV's will be performed using the following procedure:
1.
Turn MSIV control ewitch to OPEN 'JLOW TEST pocition.
2.
Slow full close the MSIV using the test push button, 3.
Turn MSIV control switch to the CLOSE position upon getting OLOSED indication.
4.
Release test push button, 5.
OMerve MSIV does not reopen.
6.
Reopen MSIV.
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G. J. Diederich 1
Station Manager GJD/RDB/kg O
O DOCUMENT ID 1787k
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ENGINEERS CHIC AGO APPEN01X II I
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January 15, 1988 To:
G.
J.
Diederich LSCS Manager
Subject:
CAL-RIII-87-026 Step Number 5 BWR Engineering has reviewed and approves Sargent & Lundy's Report CQD-038640, "Pailure of MSIV Pilot Solenoid Valve 1B21-F028C," dated January 14, 1988.
It provides a root cause for the failure and justification for continued operation of Units 1 and 2 up to their next refueling outages.
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This is based on the recommendation to institute a quarterly
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cycli.g in.terval for the six (6) months of ASCO pilot valve cperatior followed by monthly tests.
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Massin (1/1)
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Hammerich (1/1)
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Allen (1/1)
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