ML20112C874
| ML20112C874 | |
| Person / Time | |
|---|---|
| Site: | Bellefonte  |
| Issue date: | 02/27/1985 |
| From: | Hufham J TENNESSEE VALLEY AUTHORITY |
| To: | Grace J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| References | |
| NUDOCS 8503220168 | |
| Download: ML20112C874 (2) | |
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TENNESSEE VALLEY AUTHORITY j
CHATTANOOGA. TENNESSEE 374ol 1630 Chestnut Street Tower II 85 tua a gepuagg27,1985 BLRD-50-438/83-56 BLRD-50-439/83-49 U.S. Nuclear Regulatory Commission Region II Attn:
Dr. J. Nelson Grace, Regional Adninistrator 101 Marietta Street, NW, Suite 2900 Atlanta, Georgia 30323
Dear Dr. Grace:
BELLEFWTE NUCLEAR PLANT WITS 1 AND 2 - MASS T HVAC SUPPORTS Nor INCLUDED IN FEQUENCY CALCULATIONS - BLRD-50-438/83-56, BLRD-50-439/83 THIRD INTERIM REPORT The subject deficiency was initially reported to NRC-0IE Inspector P. E. Fredrickson on October 20, 1983 in accordanoe with 10 TR 50.55(e) as NCR BLN BLP 8336. This was followed by our interim reports dated November 18, 1983 and May 15, 1984.
Enclosed is our third interim report.
We expect to sutanit our next report on or about July 29, 1985.
If you have any questions, please get in touch with R. H. Shell at FTS 858-2688.
Very truly yours, TENNESSEE VALLEY AUTHORITY J. W. Hufham, Manager Licensing and Regulations Enclosure oc (Enclosure):
Mr. Richard C. DeYoung, Director Office of Inspection and Enforcement U.S. Nuclear Regulatory Commission Washington, D.C.
20555 Records Center Institute of Nuclear Power Operations 1100 Circle 75 Parkway, Suite 1500 Atlanta, Georgia 30339 fEA7
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OFRCIAE COPYt 8503220168 050227
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PDR ADOCK 05000438 An Equal Opportunity Employer S
PDR i
ENCLOSURE
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BELLEFCNTE NUCLEAR PLANT UNITS 1 AND 2 MASS OF HEATING, VENTILATING, AND AIR-CDNDITIONING SUPPORTS NOT INCLUDED IN FEQUENCY CALCULATIONS BLRD-50-438/83-56, BLRD-50-439/83-49 NCR BLN BLP 8336 10 CFR 50.55(e)
THIRD INTERIM REPORT Description of Deficiency Bellefonte Nuclear Plant (BLN) design criteria N4-50-D716, section 8.1 requires that the mass of a support be included in the evaluation of the natural frequency of that support in the restrained direction when the A review of support's mass is greater than 50 percent of the supported mass.
heating, ventilating, and air-conditioning (HVAC) support calculations initiated to address generic concerns of the separately reported item, NCR WBN SWP 8254 (CDR 390/83-48 and 391/83-46), has revealed that some supports identified in the TVA design drawing series listed below were rot designed to the design criteria requirements.
Affected drawing series:
4AWO867-X2 4 AWO871-X2 4 AWO868-X2 4AWO865-X2 4AWO869-X2 4AWO759-X2 4 AWO870-X2 4 AWO532-X2 TVA has determined that the cause of this deficiency was the ambiguous and misleading wording of section 8.1 of N4-50-D716.
In the second paragraph of this section two methods of designing duct supports (the allowable stress limit and the static deflection limit methods) are listed while the following paragraph discusses considerations used in the static deflection limit metrod In this paragraph the statement, "the weight of the support need not only.
be considered unless it is estimated to be 50 percent or more of the supported duct weights," appears. Since there was no mention of the weight of the support being included in calculations using the allowable stress limit, it was reasoned in sone instances that such an inclusion was not t
l required.
Interim Progress TVA has reviewed calculations for duct supports in the reactor building and l
for duct supports in stage II of the Auxiliary Building. To date, no l
discrepancies have been found or drawing revisions required due to a misapplication of section 8.1 of N4-50-D716. TV A is continuing its investigation of duct supports in other category I structures.
TVA is also in the pecoess of revising N4-50-D716 to clearly indicate that the mass of the support must be used in both the stress limit and the deflection limit methods of the design of duct supports in category I p
structures and has instructed duct support designers to the proper application of the N4-50-ITT16 currently in use.
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