ML20093A443
| ML20093A443 | |
| Person / Time | |
|---|---|
| Site: | Wolf Creek  |
| Issue date: | 06/29/1984 |
| From: | Koester G KANSAS GAS & ELECTRIC CO. |
| To: | Johnson E NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV) |
| References | |
| KMLNRC-84-106, NUDOCS 8407100504 | |
| Download: ML20093A443 (2) | |
Text
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t KANSAS GAS AND ELECTRIC COMPANY THE ELECTAFC COMPANY OLENN L MOESTER VCE paf S40ENT
- NUCL$&R June 29, 1984
/
Mr. E.H. Johrison, Acting Chief
]g Reactor Project Branch 2 U.S. Nuclear Regulatory Commission Region IV h
611 Ryan Plaza Drive, Suite 1000 JUL - 51984 Arlington, Texas 76011 j
i u
KMLNRC 84-106 Re:
Docket No. STN 50-482 Subj: Potential 10CPR50.55(e) Interim Report -
Microbiologically Influenced Corrosion
Dear Mr. Johnson:
This letter provides an interim report on a potential 10CFR50.55(e) con-cerning Microbiologically Influenced Corrosion in heat exchangers at Wolf Creek Generating Station. This matter was initially reported by Mr. H.K. Chernoff of Kansas Gas and Electric Company (KG&E) to Mr. William Johnson of the Nuclear Regulatory Commission, Region IV on June 1,1984.
Due to an excessive demineralized water make-up rate to the turbine-generator stator cooling water system, an examination of the stator cooling water heat exchangers (non safety-related) was performed. An eddy current inspection of the heat exchangers revealed pitting of the heat exchanger tube walls. The cddy current test results identified that approximately 28% of the tubes exhibited some pitting. Preliminary investigations con-ducted by the Architect / Engineer and the turbine-generator vendor indicated that the source of the tube damage was microbiologically influenced corrosion (MIC), that is, corrosion caused in part by the life cycle of certain microorganisms. These organisms entered the heat exchanger by wcy of the service water (EA) system before Wolf Creek's service water chemical treat-ment system was operational. Water samples have been taken from Wolf Creek Generating Station (WCGS) cooling I ake in an attempt to culture and isolate the responsible microorganism (s).
Since the WCGS cooling lake supplies cooling water to,some safety-related heat exchangers, KG&E elected to inspect all heat exchangers that were exposed to lake water. These inspections have not been completed, however, a small number of tubes in four safety-related heat exchangers (Chemical and Volume Control System Chiller, Diesel Generator
'A' Intercooler, Jacket Water Heat Exchanger and Lube oil cooler) exhibit some pitting. The O
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Mr. E.H. Johnson l
KMLNRC 84-106 June 29, 1984 Architect / Engineer is evaluating the results of the aforementioned activities to determine what corrective action, if any, will be necessary to repair the affected heat exchangers and eliminate the microorganism (s).
Final resolution of this matter will await the completion of the eddy current examinations and evaluation of those results by the Architect /
Engineer. In the interim, the status of this potential 10CFR50.55(e) will be carried on the monthly' status update as file 53564-K141. The final report or any significant new information will be submitted by separate correspondence.
Please direct any questions concerning this subject to me or to Mr. Otto Maynard of my staff.
Yours very truly,
//M Glenn L. Koester Vice President - Nuclear i
GLK bb xc: RCDeYoung P0'Connor (2)
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