ML20012D666
| ML20012D666 | |
| Person / Time | |
|---|---|
| Site: | Catawba  |
| Issue date: | 03/21/1990 |
| From: | Tucker H DUKE POWER CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| RTR-NUREG-0612, RTR-NUREG-612 NUDOCS 9003280212 | |
| Download: ML20012D666 (3) | |
Text
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DUKE POWER March 121,: 1990.
U.,S. Nuclear, Regulatory Commission
' Attention:
Document Control Desk
{.7 Washington ~,-D.
C.
20555-
Subject:
Catawba Nuclear Station, Units 1 and 2 Docket Nos. 50-413 and 50-414 Control' _of llcavy Loads at Nuclear Power Plants Gentlemen:
If MyEletter dated March 15, 1990 requested NRC approval'of a revision to a station commitment'that was made in response to NUREG-0612 " Control of'
.lleavy-Loads at Nuclear-Power. Plants." -The commitment change would allow tho' station to handle heavy loads inside-the reactor building during Modes-
'1
.4 for two specific; activities. These activities consist'of preventive maintenance on the reactor building polar crane and the removal of the j
F pressurizer enclosure hatch to facilitate inspections inside the pressurizer cavity. Duke Power's analyses of= load drop. scenarios associated with the two-activities showed'no adverse impact'on safe shutdown. functions.
During-a conference call--on-March-16, 1990 with the-NRC Staff.-several questions _were raised by Mssrs. Kirslis and Wagner.. Duke has completed the additional' review and' analysis' based on-the questions and the results are summarized as-follows:-
1.
Upper Containment' piping composite drawings and Upper Containment _
electrical' equipment drawings'were reviewed and no safety related~
components were in'the drop paths. This was verified in Unit 1 with a visual inspection..A similar inspection will be performed for' Unit 2.
1 2.
A drop analysis was performed for two additional cases: the pressurizer hatch edge (impact area = 58 square inches) striking
~
the operating floor or CRDM missile shields; and the pressurizer hatch corner (impact area = 28.27 square inches) striking the i
operating floor or CRDM' missile shields. These drop analyses were done with the same-conditions as outlined in the March 15, 1990 letter with the exception of the impact areas. The results j
of the two additional cases were the pressurizer hatch does not i
penetrate the target areas, and the structural stability and functional requirements are maintained, and no secondary missiles f E, due to scabbing are generated.
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-U -S. Nuc1=r R:gul tory Commiccion March 21, 1990-h(
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3.
An additional review of the polar crane load block and hook drop p'
was performed._ The crane hook hitting the operating floor or missile shicids on its edge (impact area = 131 square inches) is the bounding drop scenario.. The results of the above bounding case.were that the operating floor / missile shields were not penetrated, the structural stability and functional requirements are maintained, and no secondary missiles due to scabbing are generated..
Additionally,-several more questions were raised by Mssrs. Kirslis and t
Chan'during a conference call on March 21, 1990. Duke has completed ~an i
additional review based on the latest questions and the results are
. summarized as-follows:
1.
Summary of impact dimensions used to obtain impact areas are as.
follows:
a) Pressurizer Hatch Flat Drop:
41"~x 41" b) Pressurizer Hatch Edge Drop:
29" x 2" c) Pressurizer Hatch Corner Drop: effective diameter = 6" d) Polar Crane Block & Cable Drop: Hook edge = 16.1/8" x 8 1/8" L
2.
Summary of reinforcing spacing:
a)' Operating Floor Illi bars @ 6", Top and Bottom, each direction, b) CRDM Missile Shields:
//11 bars @ 6", Top and Bottom 3.
The ductility ratio in bending mode for the target concrete
-(operating floor'and/or.CRDM Missile Shields) was kept at or below 10.
4'.
The polar crane bridge seismic restraints are designed for SSE loads and protect against both lateral and uplift / overturning loads.
In conclusion, there are no safety related components in the drop zones, and the analyses of the postulated load drops indicate that the intent of NUREG-0612 has been met.
Very truly yours, b/<-
Hal B. Tucker RGM/03199001 Attachment
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' t U. S.: Nuclear _ Regulatory Commission
=
' March 21, 1990 Page 3:
.a cci Mr.-S. D. Ebneter, Regional-Administrator' O. S. Nuclear Regulatory Commission Region 11 101 Marietta Street, NW, Suite 2900 Atlanta, Georgia 30323 Dr. K.'N, Jabbour
.0ffice of Nuclear Regulation U. S. Nuclear Regulatory Commission One White Flint North Mail Stop 14H25 Washington, D.C.
20555 Mr. W. T.' Orders NRC-Resident Inspector Catawba Nuclear Station