ML20027A501

Responds to Insp Rept 50-482/78-04.Investigation of 90-day Cylinder Breaks Is Underway.Lab Tests Show Base Mat Concrete Is Above Design Strength.Exact Cause of Low Breaks Is Not Established.Will Forward Final Rept

ML20027A501
Person / Time
Site:	Wolf Creek
Issue date:	05/03/1978
From:	Koester G KANSAS GAS & ELECTRIC CO.
To:	Seidle W NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
Shared Package
ML20027A495	List: ML20027A497 ML20027A498 ML20027A499 ML20027A500 ML20027A501
References
TASK-AS, TASK-BN-78-31 BN--78-31, BN-78-31, NUDOCS 7812110282
Download: ML20027A501 (3)

Text

- ' ' . .

. ANSAS GAS,AND ELECTRIC CtWPNd?

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May 3, 1973 .

Mr. W.C. Seidle, Chief .- .

l Reactor Construction and Engineering -

Support Branch U.S. Nuclear Regulatory Ca*-'4 *sion Region IV 611 Ryan Pll:a Drive, Suite 1000 Arlington, Texas 76011

/ Ra2 Response to Inspection Report NRC Docket No. 'STN 50-482/Rpt. 04 ,

Containment Base . Mat Ninety-Day

• Cylinder Brenks '

Dear Mr..Seidle:

As indicated in the referenced report, an investigation of 90-dar cylinder break,s has been initiated and is continuing. To date no

' Tha oroblem with laboratory the actual tests basebymat conducted theconcrete Portland has h*enAssociation Cement irlantifiari.i2uficate that the base mat' concrete' is considerably above , design strength. .

The exact cause of the low breaks has not been definitely established and investigations are continuing to try and identify the exact cause.

Physical misalignment of the cylinder compression testing machine has been found. This condition is being analyzed in an effort to quantify

• the effect on indicated strength. ,

Our pre 14 min =_7 investigations of this matter 1.2djcate that this problem is not reportable under regulation 50.55(R); however, when our investigations are co:nplete, we will forward to you a copy of our final report. It is estimated that it will take about 90 days to

' complete our investigations and prepare the final report.

Yours very truly, GIX:bb cc: JOArterburn EWCreel .

WEHitt DI'McPhee .

7812110282 -

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C?a0407 TABLP, T -

PCA COMPRC,SSION TEST DATA _ -

Power Block Basennt e r.1;- a u . cyal.Oenn 2x: 1: . cuh== -

(14 Acril 1978) (17 Anril 19781 Strength Type of Corrected Strength Cv1. No. osi Ercak Cyl. No. _( 809, of total) 231_

7156 6680 D/C 6408 6680, 6700 7202 6690 D/C. 6413 6400, 7950 7208 6260 D/C 6438 6350 l 7214 6580 D/C 6443 5700, 6440 7220 5830 D/C 6449 5640 7222 5930 D/C .

723B 5960 D/C 6450 5280 7244 6330 D/C 64,56 6500 7250 6170 D 7256 6610 D/C 6473 5060, 5210

, 7262 G390 D/C. 6479 6380 72S0 6560 D/C 6498. 6200 7286 5910 D 6509 5540 7313 6140 D/T 6510 5160, 5100 7325 6530 D/C 6707- 5160, 5920 7331 6030 L/T Ave. = 5970 7337 5910 -

D/C Max. = 7950 7343 '

5970 D/C Min. = 5060 7356' 5860 D/T Std. Dev. = 752 7362 5980 D/C Ave. = 6220 Max. = 6G90 Min. = 5830 Std. Dev. = 302 ., ,

p = diagonal Data from Ccmcanion cylinders C

• conical tested bv Danici -

L = lengthwise T = transverse Ave. = 5370 l

Max. = 6110 .

Min. = 43GO .

Std. Dev. = 477 e ,

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rugu 14 cz as

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- - 'T he,sc data indiento normal strcngths at 90 days. Aggregatas

' vere sheared in all cylinder breaks and the most common frac- ~

ture surface was a combination of diaconal and conical forr.:,

not substanti.stly dif ferent f rom forms observed on Daniel's, s c, u . 4 et11,4ano. rw. 41=cen=1 w e. .. 4 ,a t c h e ha axolaf.ned by the fact that most of the cylinder bottoms were clightly rounded, with the relative high-point in the center. ,

A 2x2" cube was cut from remnant of Cylinder No. 6431 and cc preceion-tected on April 7, 1978. Compressive strength, af ter 20% correction, was 6810 psi. This compressive stren5th is not included in the statistical calculations.

/

DON CM4PsELL Petrographic Services ad CT-0407 .

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