ML20059G304
| ML20059G304 | |
| Person / Time | |
|---|---|
| Site: | Dresden  |
| Issue date: | 10/22/1993 |
| From: | Johnson I COMMONWEALTH EDISON CO. |
| To: | Murley T NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM), Office of Nuclear Reactor Regulation |
| References | |
| REF-PT21-93 NUDOCS 9311080062 | |
| Download: ML20059G304 (3) | |
Text
Commonw;11th Edison i
y O~ - 1400 Opus Place Downers Grove, Illinois 60515 l
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October 22,1993 q
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Dr. Thomas E. Murley, Director Office of Nuclear Reactor Regulation l
U.S. Nuclear Regulatory Commission Washington D.C. 20555 Attn: Document Control Desk
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Subject:
Commonwealth Edison Company _
10 CFR Part 21 Final Report (File 93-021) a
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C&S Valve Co. Dual Plate Check Valve Seat Failure
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Dear Dr. Murley:
The purpose of this letter is to notify the_ NRC Staff of concerns by t
Commonwealth Edison Company (CECO) toward Dual Plate Check Valve with Viton Seats supplied to CECO by C & S Valve Co.'since September 28,1990.
l These valves were used in safety-related systems at CECO's Dresden Nuclear 1
Station. Provided as an attachment to this letter is CECO's notification in i
accordance with the requirements of 10 CFR Part 21, Section 21.1.(b),21.3a(3),
and 21.3.d(4).
i As stated in the attached Corrective Actions, CECO reviewed all installed 'C j
& S Dual Plate Check Valves with Viton Seats to determine the immediate impact L!
of this concern. CECO has successfully dispositioned.all the subject valves installed at Dresden Station.
If there are any questions reguarding this notification, please direct them to Luke D. Kim at (708) 663-7457.
Respectfully, i
- y i
OFFICI AL SEAL" l
S ANDH A C. L AR A i
NOTARY PUEUC. STATE OF ILUNOIS s 1
1903959 T @ M Irene M. Joh son i
Licensing Operations Director j
Attachment:
10 CFR Part 21 Final Report -
se of
- county of LM-o 9
cc:
J. Martin, Regional Administrator - RIII
. J.E. Dyer, Directorate III-2 Director, NRR Netary Pubite x
-9311000062 931022
,/ f PDR ADOCK 05000010:
LS-PDR. _
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C&S Dual Plate Check Valves with Viton Seats-Part 21 File No. 93021 October 22, 1993 Applicability This notification is submitted in accordance with the requirements of 10 CFR 21, section 21.l(b), 21.3a(3), and 21.3.d(4).
i Identification of Facility and Component This notification concerns dual plate check valves with Viton seats which were supplied by C & S Valve Co. and installed for use in safety-related.
I systems at Dresden nuclear power plant.
No other commonwealth Edison nuclear power plants are affected with this Part 21 notification.
Identification of Component Manufacturer C & S Valve Co.
40 Chestnut Ave.
Westmont, II. 60559 (708) 789-8900 Nature of Defect Inspection of the 2-1501-63A check valve showed that the Viton seat had partially separated from the check valve body.
Since this was the second failure of a similar nature the check valve was sent to Ceco's metallurgical lab for detailed evaluation.
It was determined that the failure was due to inadequate process control-by the manufacturer, C&S Valve Co.
Ceco identified the problem as an adhesive failure, resulting from one or more of the following factors.
o Degree of surface preparation o Time delays between blasting and adhesive application and between adhesive application and bonding.
o Adhesive coating thickness o Moisture absorbed by the adhesive.
C & S Valve Co. contracts Courtin Rubber and Gasket Co. to bond the Viton, courtin Rubber and Gasket Co. performs the bonding under a.
procedure written and qualified by C & S Valve Co.
The consequences of seat failure of the LPCI valves is mitigated by the header pressure monitoring system and therefore has no adverse safety Ompact. The failure of the HPCI valves would have a minimum affect on the HPCI system flow rate and therefore has no adverse safety impact.
However, the valve used in CCSW system can have an adverse impact.
Specifically, loss of pressure in the CCSW pump loops can occur if
b leakage due to seat failure of the CCSW pump discharge check valves, 2(3) 1501-1A thru-D occurs.
e Time of Discovery on September 23, 1993, Ceco concluded that the check valve failure was attributed to inadequate process control by the manufacturer C&S. Valve-
{
Co.
On September 29, 1993, CECO determined that although the manufacturer 4
classified the seat as non safety related, the failure of the check valve seat could have adverse safety impact for certain applications.
Number and Location of All Defective Component The C&S check valves with Viton seats installed at Dresden station are:
2 - 4" HPCI Auxiliary Cooling Pump Discharge (2(3)-2301-51) 4 - 10" CCSW Pump Discharge (2(3)-1501-1B and 2(3)-1501-1D) 4 - 12" LPCI Pump Discharge (2(3)-1501-63A and 2(3)-1501-63B)
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Corrective Actions Commonwealth Edison's immediate corrective action was to identify the locations of all C&S dual plate check valves with Viton seats.
It was determined that only Dresden Station has the potentially defective C&S
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dual plate check valves with Viton seats.
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An operability determination of all C&S dual plate check valves with Viton' seats was completed on September 30, 1993, i
Periodic surveillance of the CCSW pump pressure has been undertaken as a compensatory action to ensure continued operability of the CCSW pump.
The purchasing description for this item will be revised to include Ceco witnessing the fabrication bonding process to the valve body. This will 1
confirm that the root cause of the potential problem has been identified
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and corrected.
Contacts Questions pertaining to this notification should be addressed to:
Luke Kim Nuclear Engineering and Technology Services
.l Commonwealth Edison Company 1400 Opus Place, Suite 400 Downers Grove, Ill. 60515.
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