ML072080346
| ML072080346 | |
| Person / Time | |
|---|---|
| Site: | Sequoyah  |
| Issue date: | 07/23/2007 |
| From: | Wetzel B Tennessee Valley Authority |
| To: | Rulemaking, Directives, and Editing Branch |
| References | |
| 72FR29010 00003 | |
| Download: ML072080346 (2) | |
Text
L2 Tennessee Valley Authority, 1101 Market Streeet., Chat.'zartcoga. - -e .- '0--.(
t-,,S July 23, 2007 U.S. Nuclear Regulatory Commission r~.)
MS T6-D59 11545 Rockville Pike 73] M Rockville, Maryland 20852-2738 Ti ATTN: Chief, Rulemaking, Directives and Editing Branch 71]
Gentlemen:
TI C/
TENNESSEE VALLEY AUTHORITY (TVA) - Comments ON Proposed GenerfcJ Communication CONCERNING Managing gas intrusion (Vol. 72 FR 29010-290V15)
TVA appreciates the opportunity to review and provide comments to the subject generic letter. The generic letter addresses the issue of gas intrusion into the emergency core cooling, decay heat removal, and containment spray systems.
.TVA offers the following comment:
TVA believes that casting the 40 events at Sequoyah mentioned in the subject Federal Register Notice as "waterhammer events" is misleading. In common nuclear industry use, the term waterhammer has the connotation of a large pressure transient that causes significant dynamic loads in the associated piping, subsequent pipe movement, and (in many cases) damage to the piping supports and the piping itself.
The subject events at Sequoyah varied widely in magnitude and did not involve violent pipe movement. As mentioned in the draft, the events did not result in Residual Heat Removal (RHR) system inoperability. Rather, most of these events occurred when the Sequoyah RHR system was isolated. In this condition, "out gas" pockets formed within system high points and caused less significant gas bubble compressions. -Ifthe generic letter continues to reference the 40 Sequoyah events, the description of these events should be modified to provide a proper context.
If you have questions regarding our comments, please contact Rob Brown at (423) 751-7228.
Sincerely, Beth A. Wetzel Manager, Corporate Licensing and Industry Affairs Nni5 Dor'L'/ P")P er Jld 1
U.S. Regulatory Commission Page 2 July 23, 2007 RMB:RPS cc: Tony Langley, PAB 1G-BFN W. M. Justice, LP 6A-C G. W. Morris, OPS 4C-SQN L. A. Moore, BR4X-C W. A. Eberly, LP 4H-C J. D. Smith, ADM 1L-WBN K. W. Whittenburg, SP 2B-C EDMS, WT CA-K