ML20027A498

Presents Results of Review of Low Strength Values for Facility Base Mat 90-day Concrete Cylinders.Base Mat Concrete Meets Spec Requirements & All Matls Used in Mix Are Acceptable

ML20027A498
Person / Time
Site:	Wolf Creek
Issue date:	11/30/1978
From:	Turdera J BECHTEL GROUP, INC., BECHTEL POWER CORP.
To:	Mary Johnson KANSAS GAS & ELECTRIC CO.
Shared Package
ML20027A495	List: ML20027A497 ML20027A498 ML20027A499 ML20027A500 ML20027A501
References
781024, NUDOCS 7812110273
Download: ML20027A498 (3)

Text

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Bechtel Power Corporation Engineers - Constructors 15740 Shady Grove Road 2 Caithersburg. Maryland 20760 p..

301-9482700 .

Et. M. L. Johnson p,~ ., .,y Directot-Plant Engineering fe,- T. '

Kanscs Gas & Electric Co=pany 00I 2 4 1975 y 'ri.

201 Kerth Market Street , if  :,5 :

Eichita, Kansas 67201

%g.:...-

ELKI %lL File: C191 M.

Bechtel Job Eo. 10466 SKUPPS Proj ect..

T Concrete Testing of KG5E Reactor Building Esse Mat Ref: 1. PCA letter Shideler to Phillips dated 4/19/78

2. DIC letter Eitt to Arterburn-dated 7/25/78

. 3. DIC letter Hitt to Arterburn dated 10/5/78 Encl: A. NCR 1-0229-C i-

Dear Mr. Johnson:

At the request of KG&E, techtel has revicteed the studies conducted to investigate the icw strength values ind1cceed for the Wolf Creek base cat 90-day concrete cylinders (see enclosed NCR 1-0229-C).

These studies successfully deconstrate the acceptability of the r.sterials used in the ci): and the in-situ strength of the bcse cat concrete. In sucmary, the studies include:

! 1. PCA report attached to letter Shideler to Phillips dcted '

( April 19, 1978. -

a. PCA investigated all concrete ingredients (coarse aggregate.

l fine eggregate, ce=ent, ad=ixture). None of the ingredients l were found to have any adverse properties.

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I b. PCA investigated sa=ples of the actual concrete cylinders for the base cat and found that the concretc is of a good l

l quality and indiccted that the actual strength should be well above the 5000 psi design rcquire=ent.

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l l 7 812110 213>

' Bechtel Power Corporatio:

Mr. 1. I.. Johnscu .

c. PCA saw cut and tested 19 cubes from cylinders previously tested for the bcse n:st concretc at 90 days. The cubes were representative of high and low strength cylinders. All of the cube strength results, reported as equivalent cylinder strengths by decreasing the actual cube strength 20%, shoved a strength exceeding the 5000 psi design strength (P.ax. 7950 psi, Min. 5060 psi and Average of 5970 psi) . It should be noted that the concrete had been previously stressed during testing of the cylinders, so it is probable that initici hair line '

cracks existed in the test cubes. Therefore, results cf tested cubes are probably on the conservative side.

2. DIC report on Windsor Probe testing program attached to letter Eitt to Arterburn dated July 25, 1978.

The results of a correlation between 90 day Windsor probe tests I

and 90 day 6 x 12 inch cylinfar tests using concrete test slabs and cc=panion cylinders of the scme mix design as the Reactor Euilding base mat showed that the average Windsor p;obe results were 678 psi higher than those of the cylinders (Windsor probe:

Mcx. 7550 psi, Min. 7200 psi, Average 7355 psi; CyMMers: Max.

6940 psi, Min. 6550 psi, Average 6677 psi) . Windsor probe results, therefore average 678 x 100=9.22% higher than the cylinder results.

7355 DIC reported an average of 6495 psi (Max. 6992 psi, Min. 5916 psi) for 33 Windsor probe readings taken on the circueference of the base cat at 10 degrees intervals (3 readings not avc11chle).

Applying the results of the test slabs correlation to the average' Windsor probe readings taken on the base est, the corresponding cylinder strength for the base mat concrete is estinated to be:

1 6495 x 00 100

- -9.2') = 5896 psi ,

t

3. Investigation cf the testing eschine performed by PCA at the request of DIC (see report attached to letter Bitt to Arterburn dated cetober 5,1978) indicated that misalignment of cylinders in the testing =achine or misalip;nment of the =acFhe parts could reduce the test results by as much as 27 percent.. For exa=ple, the studies demonstrate that if the cylindc was located beneath the center of the upper swivel head of the testing machine, the strength would be 7 1/2 higher than the indicated strength.

Although test f actors influenced the results, there is no way to quantify their actual effccc.

4

Bechtel Power Corporctior Mr. M. L. Johnson .

4. DIC computer output for the cylinder brcsks, which is also attached to the letter Mitt to Arterburn dated October 5,1978 indicated a trend of changing resules with t-be between dates when tha testing machine was serviced. After servicing and calibration of the machine subsequent to the base =at cylinder breaks the test results were shown to have a bisher strength level and in-proved consistency. This indicates that the =achins was a factor effecting the test results. Eouever, the czgnitude of this affect is not known.

The referenced docue,ents discussed above da=onst te that the in-situ strength cf the base =at concrete =eets specification requiro.wnts and all caterials used in the nix are acceptable.

i Based on the above there is no =aterial noncenformance and NCR,1-0225-C is returned since no further Bechtel action is required.

, .ruly you , .

, b

, M aurcers Project Engineering Manager MAD /mef ,

cc: K. A. Petrick , v/1

• J. M. Evans I. D. Tarver J. Arterburn

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