ML20062J881
| ML20062J881 | |
| Person / Time | |
|---|---|
| Site: | Bellefonte  |
| Issue date: | 08/11/1982 |
| From: | Mills L TENNESSEE VALLEY AUTHORITY |
| To: | James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| References | |
| 10CFR-050.55E, 10CFR-50.55E, NUDOCS 8208160490 | |
| Download: ML20062J881 (2) | |
Text
C y/
TENNESSEE VALLEY AUTHORITY CH ATTANOOGA. TENNESSEE 37401 400 Chestnut Street Tower II August 11, 1982 ie 5
BLRD-50-438/81-07 g
BLRD-50-439/81-07 ru ni d
a:
U.S. Nuclear Regulatory Commission Region II Attn:
Mr. James P. O'Reilly, Regional Administrator
.c 101 Marietta Street, Suite 3100 Atlanta, Georgia 30303
Dear Mr. O'Reilly:
BELLEFONTE NUCLEAR PLANT UNITS 1 AND 2 - CORROSION OF CARBON STEEL PIPING -
BLED-50-438/81-07, BLRD-50-439/81 SEVENTH INTERIM REPORT The subject nonconformance was initially reported to NRC-0IE Inspector F. S. Cantrell on December 30, 1980, in accordance with 10 CFR 50.55(e) as NCR BLN NEB 8010. This was followed by our interim reports dated January 29, May 22, September 23, November 12, and December 21, 1981 and March 2, 1982. Enclosed is our seventh interim report. This noncon-formance has also been reported for Sequoyah and Watts Bar Nuclear Plants.
We expect to submit our next report by January 6,1983 If you have any questions concerning this matter, please get in touch with R. H. Shell at FTS 858-2688.
Very truly yours, TENNESSEE VALLEY AUTHORITY L. M. Mills, Manager Nuclear Licensing Enclosure cc:
Mr. Richard C. DeYoung, Director (Enclosure)
Office of Inspection and Enforcement U.S. Nuclear Regulatory Commission Washington, DC 20555 8208160490 820811 OFFICIAL COPVd PDR ADOCK 05000438 L - -
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[ Af An Equal Opportunity Employer
- s y e.
ENCLOSURE BELLEFONTE NUCLEAR PLANT UNITS 1 AND 2 CORROSION OF CARBON STEEL PIPING NCR BLN NEB 8010 BLRD-50-438/81-07, BLRD-50-439/81-07 10 CFR 50.55(e)
SEVENTH INTERIM REPORT Description of Condition It has been found that the original criteria for the use of carbon steel piping in raw water systems at TVA nuclear plants may not be adequate. Corrosion has been found to cause greater than pt edicted pressure drops when pipes are sized according to standard industry practice.
In addition, the corrosion can cause a thinning of the pipe wall which may be in excess of the minimum wall thickness considered in the design of the systems. This condition could affect all raw water systems with carbon steel piping, such as the ERCW System, High Pressure Fire Protection System, and the pump room and oil coolers for the centrifugal charging pumps, the safety injection pumps, and the containment spray pumps. Also, most electrical board and room air-conditioning units use carbon steel piping.
The problem of corrosion has been the subject of considerable study at TVA.
A brief history of TVA's investigation of this matter was included in our first interim report.
Interim Progress A comprehensive he-d loss analysis of the ERCW System, completed on March _9,1982, identified several areas of the existing piping system which would become deficient over plant life. Consequently, piping modifications to correct these deficiencies were also defined.
However, subsequent to the head loss analysis, a statistical analysis of meteorological and river temperature data demonstrated the validity or lowering the maximum ERCW supply temperature from 9g to g
90 F.
Therefore, the various coolgrs, designed for 95 F, have excess heat removal capacity at 90 F and should be able to reject their design heat load at a lower ERCW flow rate. Since head loss is roughly proportional to flow squared, this effectively increases the
(
capacity of the original piping system and offers the possibility of deleting many of the carbon steel to stainless steel changeouts defined in the March 9, 1982, analysis. TVA is now defining the l
lower flow rates to revise that analysis.
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