ML19257A331

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Second Interim Deficiency Rept Re Use of Incorrect Concrete Mix in Shield Bldg Wall.Final Rept Will Be Forwarded by 800314
ML19257A331
Person / Time
Site: Hartsville Tennessee Valley Authority icon.png
Issue date: 12/12/1979
From:
TENNESSEE VALLEY AUTHORITY
To:
Shared Package
ML19257A328 List:
References
NCR-HNP-B-023, NCR-HNP-B-23, NUDOCS 8001030762
Download: ML19257A331 (2)


Text

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ENCLOSURE HARTSVILLE NUCLEAR PLANT UNIT B1 USE OF INCORRECT CONCRETE MIX IN SHIELD BUILDING WALL 10CFR50.55(e) REPORT NO. 2 (INTERIM)

NCR HNP-B-023 On June 26, 1979, TVA notified NRC-0IE Inspector, W. B. Swan, that the subject NCR was potentially reportable under 10CFR50.55(e). This is the second report on the subject reportable condition. TVA will submit the final report on this deficiency on or by March 14, 1980.

Description of Deficiency The second concrete pour, number BlR-2B, of the unit B1 reactor shield building from (-)21'7" to (-)l1'7" and frog 0 to 360 degrees was placed with concrete mix 300.752 BFW p (3000 lb/in' concrete) rather than the required

, mix 401.5 BF (4000 lb/in concrete).

The deficiency was discovered by the materials engineer who made the mistake. When he was looking back over what had been done, he found that he had specified the wrong concrete mix on the pour card for that pour.

Interim Progress TVA has made compressive strength tests on three sets of cylinders taken from this pour for 90-day and 180-day breaks with results shown below:

Test Strengths Sample No. 28-Day 90-Day 180-Day 270-Day 2 2 2 1 2909 lb/in 4156 lb/in 4652 lb/in ,

2 2696 3837 4758 -

3 1839

  • 3767 To be made 2/1/80 Average 2481 -

4392

  • This sample was held out to be broken at 270 days.

GE/C. F. Braun, the shield wall designer, has elected to wait until the result of the 270-day cylinder break on sample number 3 is available to disposition the nonconformance report. TVAfee{sthattheresultsthus 2

. far, the 180-day average strength of 4392 lb/in which is almost 400 lb/in above the design requirements, show the concrete in the BlR-2B pour to be acceptable and that this position will be further supported by additional strength gained by the cylinder of sample 3 which will be broken at 270 days.

No further construction (other than the next lift which has already been poured) on this portion of unit B1 will be accomplished until after the disposition of this nonconformance report due to halting of construction on that unit.

8001030 7 9 1671 270