ML19225B193

Responds to NRC 790521 Ltr Re Violation Noted in IE Insp Repts 50-424/79-07 & 50-425/79-07.Corrective Actions:Qc Inspectors Given Procedural Instructions on Motor Shaft Rotations

ML19225B193
Person / Time
Site:	Vogtle
Issue date:	06/07/1979
From:	Staffa R, Staffa R GEORGIA POWER CO.
To:	Murphy C NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
Shared Package
ML19225B182	List: ML19225B193
References
NUDOCS 7907240270
Download: ML19225B193 (2)

Text

, r:eyg'a Poe.er Cornpany LD Fcachtr(e Street Past CM.cc Cox 4545

.. Athnta. Grarma 30303  %

Tele hone 404 522-09GO '

' ' 2.I! R C I E " b Power Suppfy Engineerin2 and Servicts POWU

' " Jneh,1979 United States Nuclear Regulatory Comission Directorate of Inspection and Enforcement Region II

REFERENCE:

101 Marietta Street, N. W. IE: II: WBS Atlanta, Georgia 30303 50-424/79-07 50-425/79-07 Attn:

Mr. C. E. Murphy File: X78G10 Genelemen:

The Georgia Power Company wishes to submit the following information concerning the noncompliance discussed in your inspection report number 50-424/79-07 and 50-425/79-07.

Georgia Power Company Quality Control inspectors have received additional instructions on the necessity for following approved procedures.

Accordingly, insulation resistance tests are being conducted as required.

A specification change to X3AR01, Section E2, has been received which amends the shaft rotation requirements for safety related motors 50 HP and la: ger to read: "The rotors of motors rated 50 HP and larger shall be turned at monthly intervals to maintain the bearing oil coating and prevent bowing of horizontal shafts and to prevent fretting of vertical shaft motor bearings. The motors shall be rotated 810 degrees, minimum." Field Procedure ED-T-06 has been revised to establish a control mechanism to preclude a recurrence of this type noncompliance. Full compliance will be achieved by July 16, 1979.

The Georgia Power Company wishes to submit the following information concerning the deviation discussed in your inspection report number 50-424/

79-07 and 50-425/79-07.

Georgia Pcw Corrpany has submitted a letter to the Director of Nuclear Reactor Regulations clarifyir.g our use of 91-day compressive strength concrete operations in the containment structures. Full compliance will be achieved upon concurrence from Nuclear Reactor Regulation.

790724cd7o 415 1 48 Iy g j l'1'*R lAL COPY.

United States Nuclear Regulatory Comission Attn: Mr. C. E. Murphy June 7, 1979 Page Two The infornation contained in the inspection report is not considered to be proprietary.

Very truly.yours,

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Laflf CWH:aaw Attachment xt: M. D. Hunt, NRC - Region II

o. H. Miller, Jr.

W. E. Ehrensperger F. G. Mitchell, Jr.

C. F. Whi tmer R. J. Kelly D. E. Dutton R. W. Staffa C. W. Hayes W. M. Johnston, Jr.

C. R. Miles, Jr.

D. L. McCrary R. A. Thomas J. A. Bailey J. L. Leamon H. A. Sindt B. L. Lex K. M. Gillespie 415 149

e fiay 11,1979 Director of fluclear Reactor Regulation ATTN: Roger S. Boyd, Director Division of Project fianagement U.S. Nuclear Regulatory Comission Washington, D.C. 2055s NRC DOCKET fiUMBERS 50-424 AND 50-425 CONSTRUCTION PERMIT fiUi3ERS CPPR-103 AND CPPR-109 ALVIN W. V0GTLE NUCLEAR PLANT UNITS 1 AND ?

PSAR SECTIO!1 3.8 CLARIFICATI0'l

Dear Mr. Boyd:

During the Nuclear Regulatory Commission inspection of the week of April 23, 1E/9, a deviation was noted between the comnitment of the Preliminary Safety Analysis Report (PSAR) and the requirenent of construction specification X2AP01.

This deviation addressed the compressive strength of concrete for the containment.

Please find enclosed the text for clarifyin0 our use of 91-day compressive strength concrete specified in the construction specification versus the 28-day compressive strength concrete referenced in the PSAR for concrete design. The designation of 91-day strength is consistent with the industry practice for massive concrete construction using mixes containing pozzolan.

Since this clarification is consistent with current industry practice ar.d has been approved on other nuclear projects, we would appreciate your earlyconcurrence.

Should you have any questions or concerns, please inquire.

Yours very truly, fY.

W. E. Ehrensperg

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WEE:db Enclosure cc: Distribution Attached Sworn to and subscribed before me, this /['lifay of flay,1979.

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Notary Public t/ ,,)

11oS23o39g My Commission expires

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2 cc: R. A. Thor:as D. E. Datton G. F. Tre', bridge, Esq.

B. L. Lex H. A. Sindt L.fT. Gucwa

);.' li. Gillespie

/u . W. Hayes J. A. Bailey 1

415 151

CLARIFICAT10tl Section 3.8.1.6.1. of the Vogtle riuclear Plant PSAR indicates that the con-pressive strength of the concrete used for the containment shall be based on 23 days. The section further indicates that the use of a pozzolan is an acceptable option.

It was therefore the intention of the PSAR to specify the necessary data requirements relative to the use of the Portland cement without pozzolan as indicated on page 3.8-37 (ASTM C150-72). The ootion of pozzolan mentioned at the end of 3.8.1.6.1. on page 3.8-40 was not developed in corresponding detail for the Vogtle Piant since, at the time of production of the PSAR in 1973, it was not known whether pozzolan would be available for use in the project concrete.

Since the construction permit was granted and further development was made in the design LNring 1977-78, it became evident that it was desirable to recommend replacement of a portion of Portland cement with fly ash to improve the overall quality of the concrete. The option of adding pozzolan, namely fly ash, to the Vogtle Nuclear Plant concrete was thereby exercised.

The more recent codes, such as AS'1E Section III, Division 2, for Concrete Peactor Vessels and Containments require, among other things, that consideration be given to minimizing the temperature rise in concrete due to heat of hydration and that investigations be performed to ensure acceptable long-term creep properties (CC-2211). Prudent design practices of massive concrete structures have censis-tently accouY ed for the interral temperature rise due to heat of hydration (see the ACI Committee 207 reports: " Mass Concrete for Dans and Other fiassive Structures" and "Effect of Restraint, Volume Change, and Reinforcement on Cracking of Massive Concrete"), and loss of prestressing force due to creep has always been an important element of prestressed concrete design (T.Y. Lin, Design of Prestressed Concrete Structures).

Reduction in cerent content by pozzolan replacement, thus reducing heat of hydra-tion, is a practice endorsed by most, if not all, codes, committees, and recognized authorities (ASf1E Section III, Division 2, ACI 349, etc.). According to Tuthill (1), use of pozzolans " oroper amounts could reduce temperature rise by 15 percent.

By reducin' the overall cement content of a concrete mix through the use of a pozzolan the ultimate creep values should also be reduced since, for a given set of materials, creep is proportional to the volume of the cement paste (cerent +

water) per unit volume of concrete. When part of Portland cceent is replaced by pozzolan this volume is reduced and so is the creep.

It has been verified that the use of pozzolan minimizes the heat of hydration and attendant thermal cracking as well as reduces ultinate creep. This is accom-plished within the frameworF of all applicable code requirements.

415 152

t' , .

The advartages of using p-( P.E F :

NRMCA Publica tion 138, February,1972) ./olan are well recognize (1)

To reduce the water recuirenent of a mix, especially if yusing ash. fl (2)

To increase workai)ility, reduce bleeding and segregation .

(3)

To change the strength gain characteristics by postponing .

n some gaintotoreduce ages latercracking.

ages, thus increasing extensibility and plastic flow (4) 10 reduce drying shrinkage.

(b)

To inprove watertightness of the concrete.

(6)

To improve waters. resistance to sulfate active soils and water alona c with a (7)

To inhibit and reduce alkali-aggregate reaction.

(8)

To reduce the cdiabatic heat of hydration of massive members.

A Corps of Engineers study cited by Philleo (2) indicates that o anthat pozz l concretes attain about the same concrete attains at 20 days. degree of maturity at age 90 days Portland time in their curing history for comparisons to be madeThus, the two age In addition, American Concrete Institute, in

" Proportioning Concrete flixes," mekes the fol' 'ir publication SP-46 titled

.ag recomendations:

crete mixes using fly ash that specifications fo '

should be modified (91 days provides from 13 complete a typical 28-day criterion to either 56 o weeks).

available subparagraph CC 2232.2C.to the desic aer and is in accordance n

, Division ?,

with periods for high early strength concretes and longer age pe concretes.

The primary reason for ewluating strengthwrom cenent hydration reaction to proceed. e bases time the o

concretes to gain strength nore slouly and over a longer period To of time illustrate the difference between Portland cementwithout cor. crete with pozzolan, figure 1 fron the paper by Hatch and Connors, reference , is attached. (3)

In conclusion, considering the messive structures of the Vogtle Project

, the need to reduce the heat of hydration is deer..ad essential and is acconplish db ing the panolanic fly ash in the mix design as provided in thee PSA1 y utiliz-Althounh not defined in detail in the PSAR, the strencth criteria based upon 91 da e.1 ploy fly strength cylinder is consistent ash to enhance with the quality of the industry practice for nix designs concrete.

415 153

The Vegtle construction specifications were prepared to allow the ust of pozzolanic fly ash mixcs for Category I, structures. Therefore, a 91-day strength criteria was establisned for pozzolan cor. crete. These specifications r.eet the requiren?nts of ANSI fi45.2.5 as modified for 91-day strenoth and also meet the applicable requirements of ACI 359. Testing records are kept at the job site and will be evaluated in accordance with the recommendations of ACI 241 as modified by ACI 349, Section 4.3.

Attachment 1 (enclosed) provides some specific data relative to some concrete placements made at the Vogtle site to date. They are based upon 91 days' cylinder break strength criteria. The construction spec:fication X2AP01 for the Vogtle Plant specifies a mininum of two cylinder breaks for 28-day or 91-day test from each 100 cu. yds. of concrete produced. Additional cylinders will be taken to monitor the quality control of the concrete production.

I 415 i54

t REF E REflCE S (1) Tuthill, L. H. , " Quality Attainc.ent and Cor:non Sense in f;uclear Concrete Construction," Concrete International, f' arch,1979.

(2) Philleo, R. E. , " Compressive Strength as a Means for Controlling the Quality of flass Concrete, " Realism In the Application of ACI

_S_tandard 214-65, ACI SP-37.

(3) Hatch, H. P. and Connors, D. fl., "Uses of Fly Ash In the American Electric Power System" Paper fio. 66F83, presented at the annual meeting of the American Institute of flining, !'etallurgical and Petroleum Enaineers, New York, February 27 - !brch 3,1966.

(4) f;ational Ready ftix Concrete Association, Publication 138, February, 1972.

f 415 155

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