ML20247F534
| ML20247F534 | |
| Person / Time | |
|---|---|
| Site: | Catawba  |
| Issue date: | 05/11/1989 |
| From: | Tucker H DUKE POWER CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| NUDOCS 8905300098 | |
| Download: ML20247F534 (3) | |
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4 Dmm Pownt Gown %NY P.O.DOX 33180 CHAnLOTTE, N.O. 28242 HALH. TUCKER TEl.EPHONE vmn renamen (704) 073 4533 moos. nam emontatmon May 11, 1989 Document Control Desk U. S. Nuclear Regulatory Commission Washington, D. C.
20555 Subj ect: Catawba Nuclear Station, Units 1 and 2 Docket No. 50-413 and 50-414 Special Report Gentlemen:
Pursuant to Technical Specifications 6.9.2, 3.8.1.1.2, and 4.8.1.1, please find attached a Special Report concerning the inoperability of the Cathodic Protection System. The Cathodic Protection System was declared inoperable on April 11, 1989.
Very truly yours, B.TA,4 Hal B. Tucker JGT/3/SR89-36 I
xc:
Mr. S. D. Ebneter Regional Administrator, Region II l
U. S. Nuclear Regulatory Commission l
101 Marietta Street, NW, Suite 2900 i
Atlanta, Georgia 30323 I
I Mr. W. T. Orders i
NRC Resident Inspector j
Catawba Nuclear Station j
l l
I 1
in S
S i
l SPECIAL REPORT CATHODIC PROTECTION SYSTEM TECH. SPEC. 3.8.1.1(g), 4.8.1.1.2(d) on April 11, 1989, the Cathodic Protection System was i
declared inoperable after the system did not pass the l
acceptance criteria of the sixty (60) day surveillance.
E Failure to restore the system to operable status within the required period of ten (10) days resulted in implementing action statement "g" of CNS Technical Specification 3.8.1.1 and Technical Specification 6.9.2.
1 On April 11, 1989, while performing the sixty (50) day surveillance on Rectifiers #7 (Unit 1 D/G Fuel Storage Tank Cathodic Protection) and #3 (Unit 2 D/G Fuel Storage Tank Cathodic Protection), the readings for Test Stations TS-34, TS-35, and TS-36 (Rectifier #7) and TS-19 (Rectifier #3) were found to be below the acceptance criteria indicating inadequate cathodic protection of the D/G Fuel Storage Tank Pipes.
The system was declared inoperable and Design Engineering was contacted.
~
On April 17, 1989, station NPD and Design Engineering personnel tested the system by checking for proper voltage on the anodes associated with Rectifiers #7 and #3.
During this testing, several anodes were found to have no. voltage supplied to them indicating cut or broken power cables.
Following the testing, it was determined that one or more of the following could have caused the low readings at the Test.
Stations:
1)
The loss of voltage at the anodes.
2)
Possible deteriorating Test Stations due to age.
3)
Possible deteriorating anodes.
Based on the above, it was determined that a survey of the areas will be required.
However, this cannot be accomplished until voltage is restored to the de-energized anodes.
Therefore, the following corrective action is planned:
1)
Restore voltage to the de-energized anodes.
2)
Adjust the output voltage of the Rectifiers to approximately 75 volts.
3)
Survey the areas to determine if adequate readings are being provided by the Test Stations.
4)
Based on the findings in the previous step, evaluate the need for additional review / testing 1
q by Design Engineering and Ebasco Consultants.
The readings that were taken from Test Stations TS-ll, TS-12, and TS-13 (Rectifier #7) and TS-20, TS-37, TS-38, TS-39, TS-40, and TS-41 (Rectifier #3) during the surveillance show that adequate protection is being provided to the D/G Fuel Storage Tanks.
The readings that were taken during the surveillance from Test Stations TS-34, TS-35, and TS-36 (Rectifier #7) and TS-19 (Rectifier #3), which provide indication of protection for the fuel storage tank pipes, show that the structure potential (voltage) with the rectifiers ON is still more negative than the natural potential (i.e., the potential with the rectifiers OFF).
Therefore, the system is providing marginal protection to the D/G Fuel Storage Tank Pipes.
In addition, per Design Engineering and industry experience, corrosion deterioration on the pipes is a long term process and poses no immediate concerns.
Planned corrective action items 1 through 3 should be completed by July 1, 1989.
Based on the results of the survey in item 3, an evaluation will be done to determine if the need for further review / testing by Design Engineering and the consultant is necessary.
A supplemental report will be provided detailing the results of the survey and what, if any, additional corrective action will be r
necessary.
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