ML20095J306
| ML20095J306 | |
| Person / Time | |
|---|---|
| Site: | Brunswick  |
| Issue date: | 04/24/1992 |
| From: | Richey R CAROLINA POWER & LIGHT CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| Shared Package | |
| ML20095J299 | List: |
| References | |
| REF-PT21-92 NUDOCS 9205010234 | |
| Download: ML20095J306 (2) | |
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CD&L o
Carolina Powo & Light Company Brunswick Nuclear Project P.
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Box 10429 Southport, NC 22461-0429 April 24, 1992 10CFR2.'
FILE:
B09-13520 U.S. Nuclear Regulatory Commission Document Control Desk Washington, DC 20555 BRUNSWIC-STEAM ELECTRIC PLANT UNITS 1 AND 2 DOCKET No. 50-325 AND 50-324 l-LICENSE No. DPR-71 AND DPR-62 INITIAL NOTIFICATION OF A 10CFR21 REPORTABLE OCCURRENCE On April 4,1992, an inspection of the Emergency Diesel Generator (EDG) Building masonry block wa!!s found _~ 40 bolts for the wall's seismic supports had not-been installed per plant drawings. A preliminary evaluation determined that this condition did not make the walls inoperable. -The scope of the inspections was expanded due to these findings. On April 7,1992, the condition of the bolting of a masonry block wall (#8) between EDG #4 and its associated 480 volt Emergency Bus result 9d in EDG #4 being declared inoperable.
The types of botting deficiencies identified to this point included:
Bolt bodies cut off and welded either to incios or outside of angle support with no hole drilled in concrete.
Complete bolts installed, but welded to inside of angle support with no L
anchor sleeve in concreta hole.
L Anchor bolt installed in angle support and sleeve, but sleeve rotated in hole.
Bolt bodies cut and set in a partial hole with no sleeve, tack welded to angle support.
l Washer plato welded on one or both sides with no bolt installed through the wail in between.
Bolt holes with no bolts installed.
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'9205010234 92o424 A0ccK0500g4 DR
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The significant nurnber of bolts that had been defectively installed during initial building ~
construction on the interior masonry block wall invalidated the seismic integrity of the wall.
The wall was restored on April 12,1992. At 0210 on April 21,1992, with Unit 1 operating at 100% reactor power and Unit 2 at 78% reactor power, a poured concrete wall (9D-1) bet'neen the #1 Emergency Diesel Generator (EDG) and the 480 volt Emergency Bus ES was declared inoperaole due to the wall's seismic support bolting. The continuing evaluation determined at 0420 on April 21, 1992, that the condition of wall CD-1 also affected the redundsnt Emergency Bus FE. With both emergency buses considered inoperable, both Units were required to be : aced in HOT SHUTDOWN within 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and COLD SHUTDOWN within the following 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br /> by Technical Specification 3.0.3. Due to the extent and location of the defective bolting this is a 10CFR21 reportable issue. The investigation into extent of this issue is stin in progress. Brown and Root was the overall constructor of the Brunswick p! ant during the early to mid-1970's when the anchor bolt installation is believed to have occurred. CP&L is st;!!in.er. iga'.ing to determine who did this particular work (anchor bolt installation) on the EDG Building. Rnpairs to re-establish seismic qualification of the walls are continuing as problems are found. The safety significance is such that both Units have been placed in COLD SHUTDOWN per Technical Spec lfications and the Emergency Buses were declared inoperable based on the conservative assumption that until the walls have been verified operable a seismic event I
could damage redundant Ernergency Buses /EDGs.
Very truly our.
R. B. Richey, Vice Pr sident Brunswick Nuc'aar Project l
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