ML19331C947
| ML19331C947 | |
| Person / Time | |
|---|---|
| Site: | Hartsville, Phipps Bend  |
| Issue date: | 08/15/1980 |
| From: | Mills L TENNESSEE VALLEY AUTHORITY |
| To: | |
| References | |
| NCR-SDDR-12, NUDOCS 8008200352 | |
| Download: ML19331C947 (3) | |
Text
T TENNESSEE VALLEY AUTHORITY CH ATTANOOG A, TENNESSEE 37401 400 Chestnut Street Tower II 506 I T August 15, 1980 Mr. James P. O'Reilly, Director Office of Inspection and Enforcement U.S. Nuclear Regulatory Commission Region II - Suite 3100 101 Marietta Street Atlante, Georgia 30303
Dear Mr. O'Reilly:
HARTSVILLE AND PHIPPS BEND NUCLEAR PLANTS - REPORTABLE DEFICIENCY -
INADEQUATE SUPPORT OF CONDENSATE HEADER (NCR SDDR-12)
Initial report of the subject deficiency was made to NRC-0IE, Region II Inspector R. W. Wright, on July 16, 1980.
In compliance with parsgraph 50.55(e) of 10 CFR Part 50, we are enclosing the final report of the subject deficiency.
If you have any questions, regarding this subject, please call Jim Domer at FTS 857-2014 Very truly yours, TENNESSEE VALLEY AUTHORITY L. M. Mills, Manager Nuclear Regulation and Safety Enclosure cc:
Mr. Victor Stello, Director (Enclosure),/
Office of Inspection and Enforcement V
l U.S. Nuclear Regulatory Commission Washington, DC 20555 i
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5 ENCLOSURE HARTSVILLE AND PHIPPS BEND NUCLEAR PLANTS INADEQUATE SUPPORT OF CONDENSATE HEADER 10CFR50.55(e) REPORT NO.1 (FINAL)
NCR SDDR-12 On July 16, 1980, TVA informed NRC-0IE, Region II Inspector R. W.
Wright, of a reportable deficiency regarding inadequate design of the support of the 36-inch condensate header line for the Hartsville and Phipps Bend Nuclear Plants. This condition was identified by telephone conversation to TVA on July 16, 1980, by the General Electric Company and C. F. Braun and does not apply to any other plants. This is the final report on the subject' reportable condition.
Description of Deficiency A STRIDE design review by C. F. Braun found a situation in which the support for the 36-inch condensate header line was designed on steel beams without any local reinforcing at the pipe wall.
A review of the load at support points shows that overstressed ccnditions would exist if this situation were not corrected.
This condensate header provides the normal water supply to high pressure core spray (HPCS) and reactor core isolation cooling (RCIC) systems. Loss of this water supply (i.e., low water level indication in the condensate header) results in automatic transfer of HPCS and RCIC to suppression pool water supply.
The condensate header for Hartsville unit A1 has been installed with the deficient design.
Safety Implications The failure of the 36-inch condensate header pipe wall might result in a delay in initiation of the low water level signal (and subsequent automatic transfer to suppression pool supply) because of a geometry or orientation change in the header. This delay might result in cavitation of and damage to HPCS and/or RCIC pumps because of low water supply, thereby compromising the performance of their safety functions.
It would in any' event reduce the overall safety margin of the plant because of loss of the normal water supply to safety systems.
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j's Corrective Actions C. F. Braun, the STRIDE designer, has revised the condensate header pipe support design by adding a spreader to the pipe wall at the point of support. This change will spread the load over the pipe wall and eliminate overstressed conditions in the pipe wall. All condensate headers aubsequently installed at Hartsville or Phipps Bend will be supported by the new design. The Hartsville unit Al condensate header will be backfitted with the new support spreader noted above. This work will be completed by February 28, 1981.
To prevent recurrence, C. F. Braun's Support Design Section has instituted a procedure to require a Stress Analysis Section review and approval of all unreinforced supports on large pipes.
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