ML20096F368
| ML20096F368 | |
| Person / Time | |
|---|---|
| Site: | Bellefonte  |
| Issue date: | 08/10/1984 |
| From: | Mills L TENNESSEE VALLEY AUTHORITY |
| To: | James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| References | |
| NUDOCS 8409070421 | |
| Download: ML20096F368 (2) | |
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TENNESSEE VALLEY-AUTHORITY CHATTANOOGA.-TENNESSEE 374of 400 Chestnut Street Tower II 84AUG H P 1. 33 iugust, 10, 1984 BLRD-50-438/82-39 BLRD-50-439/82-35 U.S. Nuclear Regulatory Commission -
. Region II Attn:
Mr. James P. O'Reilly, Regional Administrator 101 Marietta Street, NW, Suite 2900'.
Atlanta, Georgia 30323
Dear Mr. O'Reilly:
BELLEFONTE NUCLEAR PLANT UNITS 1 AND 2 - DEFICIENT PIPE SUPPORTS -
4 BLRD-50-438/82-39, DLRD-50-439/82 FINAL REPORT The subject deficiency was initially reported to NRC-0IE Inspector R. V. Crlenjak on December 15, 1981 in accordance with 10 CFR 50.55(e) as NCR BLN BLP 8130. This was followed by our interim reports dated June 21, 1982 and January 24 and July 14, 1983, and..nuary 31, 1984. Enclosed is our final report. A several week delay of this submittal was discussed with Inspector P. E. Fredrickson on July 25, 1904.
If you have any questions, please get in touch with R. H. Shell at FTS 858-2688.
"Very truly yours, i
TENNESSEE VALLEY AUTHORITY L. M. Mills, Manager Nuclear Licensing Enclosure cc (Enclosure):
Mr. Richard C. DeYoung; Director Office of Inspection and Enforcement U.S. Nuclear sgulatory Commission Washington, D.C.
20555 Records Center Institute of Nuclear Power Operations 1100 Circle 75 Parkway, Suite 1500 Atlanta, Georgia 30339 8409070421 840810 PDR ADOCK 05000438 S
})FFICIAL CMV i
An Equal Opportunity Employer
30.
ENCLOSURE BELLEFONTE NUCI. EAR PLANT UNITS 1 AND 2
-DEFICIENT PIPE SUPPORTS IBLRD-50-438/82-39, BLRD-50-439/82-35 NCR BLN BLP 8130 10 CFR 50.55(e)
FTNAL REPORT Description of Deficiency An error was discovered.in the thermal movement column of a support design load drawing (drawing No. 3BH04 19-NV-04). A zero was entered in the thermal movement colurn for the unrestrained directions of about 20 supports listed on this drawing when, in fact, there is a small amount of thermal pipe movement in these unrestrained directions. Because zero was listed as the thermal pipe movement of these supports, a frictional load was not included in the design of these supports.
An incorrect assumption concerning the significance of small thermal movements was made by the piping analysts. This was caused by an inadequate understanding of the conventions agreed to by TVA and ITT Grinnell used for defining thermal movements of less than 1/4" on tables of support loads (use of NA, blank, etc.).
The use of these conventions led to a lack of due concern on the part of piping analysts for the effects of small thermal movements on support design.
Safety Implications The failure to consider frictional loading in the design of pipe supports could, theoretically, cause the affected support to fail. Since some of the affected supports are used on primary safety-related systems, a failure of these supports could contribute to a failure of safety-related piping and, therefore, be a condition adverse to the safe operation of the plant.
Corrective Action All tables of cupport loads for alternately analyzed piping with ITT Grinnell-designed supports were inspected to identify all support points having & zero '
listed as the thermal movement in the unrestrained directions. The analysis calculations were reviewed to determine actual thermal movements.
The determination was made, based on paragraph J.2 of ITT Grinnell Engineering Instruction No. 10, that frict.onal loading needs to be evaluated only for those supports at locations where the thermal movement in the unrestrained directions equals or exceeds 1/16".
In ceder to minimize the number of supports requiring detailed evaluation, the tables of support loads were reviewed and revised to identify support load thermal movements equaling or exceeding 1/16" in the unrestrained directions.
Approximately 382 supports were identified as requiring a detailed evaluation.
As a result of this evaluation, approximately 62 support detail drawings were revised. Of this number, 39 supports require construction rework.
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Th2 rewrk required 10 documented on engineering chtnga notics 2104 and will ba -
complete b/; March 7,1987.
To prevent recurrence, TVA 'has issued a memorandum to all affected piping
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analysts instrueting ~ them to enter ' appropriate numerical data on future tables of. support loads.
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