ML20093M163
| ML20093M163 | |
| Person / Time | |
|---|---|
| Site: | Bellefonte  |
| Issue date: | 10/09/1984 |
| From: | Mills L TENNESSEE VALLEY AUTHORITY |
| To: | James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| References | |
| REF-PT21-84 NUDOCS 8410190426 | |
| Download: ML20093M163 (2) | |
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q TENNECCEE VALLEY AUTHORITY CHATTAN00GA. TENNESSEE 374ot 400 Chestnut Street Tower II
.34 BCIII P l: Eber 9,1984 BLRD-50-439/84-44 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 - INADEQUATE PRESSURIZER SUPPORT ATTACHMENTS - BLRD-50-438/84-48 AND BLRD-50-439/84 FIRST IIG RIM REPORT The subject deficiency was initially reported to NRC-0IE Inspectar P. E. Fredrickson on September 6,1984 in accordance with 10 CFR 50.55(e) as NCR BLN CEB 8413 Enclosed is our first interim report. We expect to submit our next report on or about March 22, 1985. We consider 10 CFR Part 21 applicable to this deficiency.
If you have any questions, please get in touch with R. H. Shell at FTS 858-2688.
Very truly yours, TENNESSEE VALLEY AUTHORITY L. M. Mills, Malnager Nuclear Licensing Enclosure oc:
Mr. Richard C. DeYoung, Director- (Enclosure)
Office of Inspection and Enforcement U.S. Nuclear Regulatory Commission Washington, D.C.
20555 Records Center (Enclosure)
Institute of Nuclear Power Operations 1100 circle 75 Parkway, Suite 1500 Atlanta, Georgia 30339 Oh o!och$g 1
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i ENCLOSURE; e
g BELLEFONTE NUCLEAR PLANT UNITS 1 AND 2 INADEQUATE PRESSURIZER SUPPORT ATTACHMENTS BLRD-50-438/84-48, BLRD-50-439/84-44 10 CPR 50.55(e)
NCR BLN CEB 8413 FIRST INTERIM REPORT Description of Deficiency TVA has determined that the pressurizer's upper support wall attachments are inadequate. These two wall attachments are part of Babcock and Wilcox's (B&W) of Lynchburg, Virginia, support scheme for the pressurizer, and each attachment utilizes two shear bars. These shear bars are separated from the wall attachment's anchor plates by gaps which allow for. thermal growth of the upper support member. Because of these gaps, each wall attachment separately would see a loss of coolant accident (LOCA) induced load. However, because LOCA load analysis assumed the attachments would see a LOCA induced load simultaneously (i.e., did not account for these gaps), the actual load at each support point is approximately twice the design load.
A second problem involving the shear bars also exists in that original design calculations called for dimen *ons on the shear bar which are larger than those called for in the current plant design. As a result of these reduced dimensions, the required shear strength cannot be developed from the shear bars.
Interim Progress B&W has begun a reanalysis of the pressurizer support wall attachments which assumes no gap between the attachment plates and shear bars (i.e., no allowance for thermal expansion). This reanalysis is generating new loads on the embedments for the attachments and a redesign of the shear bars and embedment is underway which will eliminate the thermal expansion gaps. This redesign is a joint effort between TVA and B&W.
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