ML20058D706
| ML20058D706 | |
| Person / Time | |
|---|---|
| Site: | Zion File:ZionSolutions icon.png |
| Issue date: | 11/24/1993 |
| From: | Simpkin T COMMONWEALTH EDISON CO. |
| To: | Murley T NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM), Office of Nuclear Reactor Regulation |
| References | |
| REF-PT21-93 93-022, 93-22, NUDOCS 9312030283 | |
| Download: ML20058D706 (3) | |
Text
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o Commonwe:lth Edison l
o n rIGr November 24,1993 e uhnois 60sts 1
Dr. Thomas E. Murley, Director Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Washington, D.C. 20555 Attn: Document Control Desk
Subject:
Commonwealth Edison Company l
10 CFR Part 21 Final Report (File 93-022)
ITI' Standard Fluid Technology Corp. Heat Exchanger Failure i
i
Dear Dr. Murley:
The purpose of this letter is to notify the NRC staff of Commonwealth Edison Company (CECO) concerns related to a heat exchanger model BCF supplied to CECO by ITT Standard Fluid Technolo-Corp. in 1989. The heat exchanger failed in an area of the cooler tube roll joint which had undergone excessive wall thinning. This heat exchanger was installed in a safety-related system at CECO's Zion Nuclear Station (2B Auxiliary Feedwater Pump Oil Cooler).
i CECO has concluded that the heat exchanger failure is attributable to l
inadequate process control by the manufacturer. An inadequate inspection requirement at CECO failed to identify the defect. The heat exchanger failure could have adverse safety impact for certain applications. Provided as an attachment to this r
letter is CECO's notification in accordance with the requirements of 10 CFR Part 21, i
Section 21.1(b),21.3a(3), and 21.3.d(4).
t j
As stated in the attached report, CECO has identified all ITT Standard Fluid j
Technology model BCF Heat Exchangers installed in its nuclear plants and has initiated appropriate corrective actions. If there are any questions regarding this.
j-notification, please direct them to this office.
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Respectfully, QIeua-a3b.
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T.W. Simpkin i
Nuclear Licensing Administrator Attachment
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J. Martin, Regional Administrator - RIII J.E. Dyer, Directorate III-2 Director, NRR l
9312030283 931124 5
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Heat Exchanger Failure of ITT Standard Fluid Technology Corp.
' Size 302, Type BCF
- Part 21 File No. 93022 November 19, 1993 Applicability i
This notification is submitted in accordance with the requirements of 10 CFR 21, section 21.1(b), 21.3a(3), and 21.3.d(4).
Identification of Facility and Component l
l This notification concerns a Heat Exchanger sice 302 type BCF which was supplied by ITT Standard Fluid Technology Corp. and
' dedicated for safety related application by Commonwealth Edison in 1989.
These Heat Exchangers were installed in-safety-related systems at Zion Nuclear Power Plant.
l Identification of Component Manufacturer ITT Standard Fluid Technology Corp.
175 Standard Park Way l
Buffalo, New York 14240 1-800-447-7700
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Nature of Defect
'l Inspection of the 2B Auxiliary Feedwater pump showed oll and j
water coming out of the lube oil cooler reservoir. Upon-
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investigation, it was determined that the lube oil heat j
exchanger had failed in the cooling tubes resulting in a-i leakage of cooling water into the oil supply.
j To determine the root cause of the lube oil cooler leaking, the heat exchanger was sent to CECO's metallurgical lab for detailed evaluation.
It was determined that the tube failure occurred in an area of the roll joint which had undergone excessive wall-thinning.
At this region the tubeLwall had been-excessively deformed during original tube installation. This weakened area was susceptible to tearing; the eventual failure was accentuated by the presence of thermal and/or vibration stresses experienced by the tube during' service, j
i The excessive wall thinning was due to inadequate process control by the manufacturer.
CECO identified the problem as an overrolling at: the heat exchanger tube sheet. The overrolling could have resulted if the tooling was off center and consequently caused excessive deformation along approximately half the
'l circumference of each tube.
i Failure of the lube oil heat exchanger can have an adverse impact on safety. Specifically, failure of the lube oil heat exchanger may render the Auxiliary Feedwater pump incapable of performing its safety function.
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'On* October 19, 1993, CECO concluded that the heat exchanger l
' failure was_ attributed to inadequate process control by'the manufacturer and inadequate inspection requirement at CECO to identify the defect.
On November 19, 1993,-Ceco determined that the failure of the l
heat exchanger could have adverse safety impact for certain l
applications.
Number and Location of All Defective Components
[
I Commonwealth Edison identified all ITT Standard Fluid l
Technology size 302, type BrF heat exchangers at all Ceco Stations and determined that no other stations except Zion have installed these BCF model heat exchanger. These heat exchangers installed at Zion Station are only on the Auxiliary Feedwater Pump skids (three for unit 1 and three l
for unit 2).
Corrective Actions All the ITT Standard Fluid Technology (size 302 and type BCF) heat exchangers will either be replaced or inspected for proper rolling prior to restart from the current dual unit outage.
The Acceptance criteria for the tube sheet rolling process targets a 5 % wall reduction, with an acceptance range being between 4 % to 7 %.
The dedication requirements for these heat exchangers will be revised within 60 days to inspect for proper rolling and to ensure that the above acceptance 4
criteria are met.
J Future actions will be to review-within 120 days the dedication process for other similar heat exchangers and determine if other dedicated heat exchangers need to be inspected and or replaced.
Contacts Questions pertaining to this notification should be addressed' to:
' Luke Kim Nuclear Engineering and Technology Services Commonwealth Edison Company 1400 Opus Place, Suite 400 Downers Grove, Ill. 60515.
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