ML20054G473
| ML20054G473 | |
| Person / Time | |
|---|---|
| Site: | Midland |
| Issue date: | 06/14/1982 |
| From: | Dewitt R CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.) |
| To: | Harold Denton Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML20054G474 | List: |
| References | |
| 17320, NUDOCS 8206210590 | |
| Download: ML20054G473 (4) | |
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Vice President Nanclear Operations y p General of fices: 1945 PerneH Road, Jackson, Michigen 49201 e (517) 788-1217 June 14, 1982 Harold R Denton, Director Office of Nuclear Reactor Regulation Division of Licensing US Nuclear Regulatory Cornmission Washington, DC 20555 MIDLAND PROJECT MIDLAND DOCKET NO 50-329, 50-330 RELATIONSHIP OF OBSERVED CONCRETE CRACK WIDTHS AND SPACING TO REINFORCEMENT RESIDUAL STRESSES FILE: 0485.16 SERIAL:
17320
REFERENCES:
(1) J W COOK LETTER TO H R DENTON, EVALUATION OF FEEDWATER ISOLATION VALVE PITS AT HIDLAND PLANT, SERIAL 15493 DATED JANUARY 25, 1982 (2) J W COOK LETTER TO H R DENTON, EVALUATION OF AUXILIARY BUILDING CONTROL TOWER AND ELECTRICAL PENETRATION AREAS AT MIDLAND PLANT, SERIAL 15527 DATED JANUARY 29, 1982 (3) J W COOK LETTER TO H R DENTON, EVALUATION OF THE EFFECT ON STRUCTURAL STRENGTH OF CRACKS IN THE WALLS OF THE DIESEL GENERATOR BUILDING, SERIAL 15978 DATED FEBRUARY 16, 1982 i
l (4) J W COOK LETTER TO H R DENTON, EVALUATION OF CRACKING IN SERVICE WATER PUMP STRUCTURE AT MIDLAND PLANT, SERIAL 16009 DATED MARCH 2, 1982 (5) J W COOK LETTER TO H R DENTON, LIMIT ANALYSIS TO EVALUATE SERVICE WATER PUMP STRUCTURE EAST AND WEST WALL CAPACITIES, SERIAL 17137 DATED MAY 7, 1982 i
(6) J W COOK LETTER TO H R DENTON, EFFECTS OF hDD!
l CRACKS ON SERVICEABILITY OF CONCRETE STRUCTURES AND REPAIR OF CRACKS, SERIAL 16884 DATED APRIL 30, 1982 (7) D G EISENHUT LETTER TO J W COOK DATED MAY 25, 1982 ENCLOSURE: OBSERVED CRACKS IN WALLS OF MIDLAND PLANT STRUCTURES References 1 through 5 above transmitted a series of reports which presented an evaluation of the effect on structural strength of cracks observed in the feedwater isolation valve pits, the auxiliary building control tower and electrical penetration areas, the diesel generator building, and the service oc0682-0125a100 8206210590 820614 PDR ADOCK 05000329 A
.2 water pump structure. These five reports were provided as the result of discussions with the NRC. Staff and its consultants at meetings held on
'i December 10. 1981 and January 11, 1982 During these' meetings, Consumers =
Power also agreed to provide the NRC w(th an evaluation of the effects of cracks on the longterm serviceability of concrete structures and with recommendations on sealing cracks. Our longterm report on serviceability was forwarded.with the enclosure to the correspondence of Reference 6.
As the result of the NRC Staff's review of the reports listed as references l' through 6, additional information was requested in Enclosure 8 of the NRC's May 25, 1982 correspondence (Reference 7). NRC Staff members requested more detailed information on the relationship between observed cracks and the potential for residual stresses in reinforcement.
In addition, information on the significance of crack width and spacing for multiple cracks was requested.
In response to these requests, we are providing the enclosed report entitled,
" Observed Cracks in Walls of Midland Plant Structures", by Messrs W G Corley and A E Fiorato of Construction Technology Laboratories, a division of the Portland Cement Association. This report presents a discussion of the observed cracks in Midland Plant structures with particular reference to the relationship between observed crack widths and residual steel stresses implied by the observed cracks. The significance and evaluation of spacing and width of multiple cracks is also discussed.
Based on the detailed technical discussion presented in the enclosed report, we believe that sufficiently co'iservative acceptance criteria for the crack monitoring program have been established. These criteria provide a sound basis for using observed ' crack width and crack spacing as a measure of the condition of the structures during the implementation of remedial measures.
Although measured displacements are recommended for use as the primary means of monitoring behavior of the structure, periodic visual inspection to monitor cracks will supplement displacement data. We believed that the displacement and crack monitoring program will provide a safe and reasonable method for assessing the condition of each structure during the underpinning operations.
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RBD/RLT/mkh CC Atomic Safety and Licensing Appeal Board, w/o CBechhoefer, ASLB, w/o MMCherry, Esq, w/o FPCowan, ASLB, w/o RJCook, Midland Resident Inspector, w/o RSDecker, ASLB, w/o SGadler, w/o JHarbour, ASLB, w/o GHarstead, Harstead Engineering, w/a DbHood, NRC, w/a (2)
DFJudd, B&W, w/o oc0682-0125a100
3 JDKane, NRC, w/a FJKelley, Esq, w/o-RBlandsman, NRC Region'III, w/a WHMarshall, w/o JPMatra, Naval Surface Weapons Center, w/a W0tto, Army Corps of Engineers, w/o WDPaton, Esq, w/o SJPoulos, Geotechnical Engineers, v/a FRinaldi, hRC, w/a HSingh, Army Corps of Engineers, w/a BStamiris, w/o' oc0682-0125a100
CONSUMERS POWER COMPANY Midland Units 1 and 2 Docket No 50-329,- 50-330 Letter Serial 17320 Dated June 14, 1982 At the request of the Commission and pursuant to the Atomic Energy Act of 1954, and the Energy Reorganization _Act of 1974, as amended and the Commission's Rules and Regulations. thereunder, Consumers Power Company submits additional information responding to NRC. requests concerning the relationship l
ofthe observed concrete crack widths'and spacing for Midland structures to the reinforcement stresses. The submittal documents _ our response to information -
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requested by the NRC Staff in Enclosure. 8 of the _ NRC's May 25,_1982 l
correspondence.
I CONSUMERS POWER COMPANY i-5 By J.iA))b S/T R B DeWitt, Vice President j
Nuclear Operations Sworn and subscribed before me this
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