ML20011A550

Requests Mod of Max Depth Requirement for Snupps Containment Structures for Areas Adjacent to Two Electrical Penetration Banks Located in Reactor Bldg,Third Through Sixth Lifts Adjacent to Auxiliary Bldg

ML20011A550
Person / Time
Site:	Wolf Creek, Callaway, Sterling, 05000484
Issue date:	05/03/1978
From:	Petrick N STANDARDIZED NUCLEAR UNIT POWER PLANT SYSTEM
To:	Grier B NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
Shared Package
ML20011A456	List: ML20011A535 ML20011A550
References
SLNRC-78-9, NUDOCS 8110130544
Download: ML20011A550 (4)

Text

.

- ENCLOSURE 2

. SNUPPS .

F9 . sianeercia.4 Nucleet Urdt Po-or Pant syn..n f

• Nicholas A. Petrick s es... es.,,y no.e Executive Director noem.ms, Me<yiend 2ceso

'3* " 8 "* May 3, 1978 .

' SLNRC 78 .9 FILE: C-112 SUBJ: Reinforcino Steel Cover Tolerances _

In Containment For SNUPPS P1 ants _

Mr. Boyce H. Grier, Director Office of Inspection and Enforcement United States. Nuclear Regulatory Comission -

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Recion I 63i Park Avenue .

King of Prussia, Pennsylvania 19406 ,

Re: STN 50-4S2 STN 50 t.33 STN 50-484' STN 50-485 -

/"~=7. STN 50-485

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Dear Mr. Grier:

Reference is made to the letter from Mr. Olan Parr, Nuclear Regulatory

- Comission to .Mr. J. K. Bryan, Union Electric Company; Mr. John Arthur, Rochester Gas and Electric Corporation; Mr. A. V. Dienhart, Northern States ?ower Company and Mr. Glenn L. Koester, Kansas Gas and E Company.

The letter provided an NRC position on maximum and minimum reinforcira steel cover tolerar.ces The enclosure to Mr. Parr's letter, in thethecontainment

" Staff Evalu- struc

• SNUPPS plants.

ation of the Design Criteria for SWPPS Plants Containment Structure",

pace 3, noted that "The staff will consider spec to tr.e maximum depth to face reinforcing".

'". There are two special casesThese whereare it may not always the areas adjacent betopessible the two to me the absolute maximum cover . electrical penetration banks which a:1 third through sixth lifts, adjacent to the auxiliary building.

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In both .these cases, the penetration areas are recessed S inches as This recess allows steel sleeves to '

illustrated in the attachment. extend a sufficient distance beyon

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room is provided to weld attaching assemblies w The outer face of the reinforcing steel adjacent to these operations. recesses is moved inward with a gradual sweep from the wall in a manner that allows a smooth stress pattern 8110130544 811007 in the concrete gDRADOCK 05000483 PDR

SLhRC 78- 9 .

- Page Two

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5 sh'd steel as shown in the attachment. The width.of this transition

' area where the face reinforcing steel cover varies as it sweeps from

. 2 inches from the wall surface to 2 inches from the face of theAt8local inch -

deep recess ranges frem 5' 2-1/2" to 15' 8" for these areas.

areas within this transition zone just adjacent to the recess, the reinfo'rcing cover may exceed the 10 inch maximum design - "er require-ment by as much as 4 inches at the extreme, including placing tolerances

• as ' illustrated in the attachment. These areas have been analyzed and found acceptable by the lead architect / engineer, Bechtel Power Corporation, usin'g the methods and criteria for crack control included in the ACI 224 committee report. This acceptability stems frcm the fact that the reinforcing steel under. consideration is in a state of' ccmpression during normal service conditions as a result of prestressing.

Except at the local areas identified here in the outer layer, reinfore -

ing steel cover on the shell of the reactor building is between 2 inches minimum and 1,0 inches maximum. . . ,

The sNUPPS utility applicants have author.ized this request for modification of the maximum depth requirement for the.SNUPPS containment structures for the special cases described above. Since this request is' generic to

• all SNU??S units, the request is bei.ng addressed to Region I as the Office of Inspection and Enforcement coordination office for the SNUPPS project.

,. ~~;.; Very gruly yours.

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' bg <Wu Nicholas A. Petrick EF3/iwb

Attachment:

cc: J. E. ArEhur '

RGE J. K. Bryan UE A. .V. Dienhart NSP G. L. Koester KGE G. Charnoff SPPT L. K. Larson LLLM e

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