ML20095L350
| ML20095L350 | |
| Person / Time | |
|---|---|
| Site: | Braidwood  |
| Issue date: | 08/16/1984 |
| From: | Swartz E COMMONWEALTH EDISON CO. |
| To: | James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| References | |
| 84-06, 84-6, 9089N, NCR-604, NUDOCS 8408300214 | |
| Download: ML20095L350 (2) | |
Text
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August 16, 1984 Mr. James G. Keppler Regional Administrator U.S.-Nuclear Regulatory Commission Region:III-799 Roosevelt Road Glen Ellyn,.ILE 60137
Subject:
Braidwood. Station Units 1 and 2 10 CFR 50.55(e) Final Report Recycle Holdup Tank Leak NRC Docket Nos. 50-456/457 Reference (a):
E. D. Swartz letterEt'o J. G. Keppler dated May 10, 1984
Dear Mr. Keppler:
On April 13, 1984,-the Commonwealth Edison Company notified your office of a deficiency reportable pursuant to 10 CFR 50.55(e) regarding a leak in the Recycle Holdup Tanks OAB0lTA and OAB0lTB at our Braidwood Station.
Reference (a) provided information
'concerning this matter to fulfill the thirty day reporting requirements.. For your tracking purposes, this deficiency was assigned Number 84-06.
The purpose of this letter is to provide your office with the final report concerning this matter.
FINAL RESOLUTION Since the submittal of our Reference (a) report, Chicago Bridge and Iron, in consultation with Parker Labs, have completed their analysis to determine the cause of our Recycle Holdup Tank leakage.
The results of this analysis indicate that
' bacteria-accelerated corrosion of weld metal-from the tank exterior'was the primary failure mechanism.
A unique set of circumstances associated with the Recycle Holdup LTank design and their. location resulted in the corrosion related leaks.
The tank bottoms were fabricated using lap joint welds which' result in exterior crevices.
In addition, the tank foundations consist of a sand bed enclosed by a' ring dall.
l Groundwater seepage into the vault area where the tank are 8408300224 840816
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3 located'wett'ed the foundation sand, which along with the weld crevices, provided an environment which promoted bacteria. growth leading-to accelerated corrosion.
Chicago Bridge and Iron is currently revising their tank design
. procedures to utilize butt weld construction for tank bottoms,
-and to eliminate the use of sand-in foundation construction.
The installation of new bottoms on the affected Braidwood
' Station tanks and foundation modification work will commence in mid-September.
This work is anticipated to be completed by December 1, 1984..This.deficiciency is being tracked by the Commonwealth Edison Company NCR #604.
Please address any questions that you or your staff may have concerning this matter to this office.
Very truly y urs
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ouglasSn$hh2 E.
Nuclear Licensing Administrator cc:
NRC Resident Inspector - Braidwood Director of Inspection and Enforcement US Nuclear Regulatory Commission Washington, DC 20555 9089N l