ML19253C599

Confirms 790831 Telcon Re 790628 Ltr Concerning 790622 Stop Work Order on Placement of safety-related Concrete.Util Will Resume Placement of Concrete in Reactor Containment Bldg Exterior Shell Walls

ML19253C599
Person / Time
Site:	South Texas
Issue date:	08/31/1979
From:	Eric Turner HOUSTON LIGHTING & POWER CO.
To:	Seidle W NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
References
ST-HL-AE-374, NUDOCS 7912060560
Download: ML19253C599 (3)

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7'Jc flousTox Liol TINo & Poweit GoneANY llocsTox. TEXAS 77001 E. A.Tunwem v'" *"$**" August 31, 1979 ST-HL-AE- 374 l SFN: C-0510 '

Mr. W. C. Seidle Branch Chief Nuclear Regulatory Commission Region IV 611 Ryan Plaza Drive, Suite 1000 Arlington, Texas 76012

Dear Mr. Seidle:

This letter is written to canfirm our telephone conversation of this date.

In our letter of June 28, 1979 concerning our stop work order of June 22, 1979 on the placement of safety-related concrete at the South Texas Project, we advised thr.t a hold would be continued on the RCB exterior shell wall placements until our evaluation war, completed and any corrective action needed was implemented.

We intend to resume placement of concrete in the RCB exterior shell walls on t'e n basis of our evaluar. ions and resultant improvements in our construction and .

quality control methods. While we have been performing the activities discussed below for all concrete place-ments our evaluation of the RCB exterior shell wall pointed to the need for increased precision and special attention due to the complexity of the placements.

Consequently, we have implemented specific measures in placement of concrete for the RCB exterior shell .

wall shown below:

1. Special attention is given to concrete production to ensure that slump, aggregate moisture, and Engineering-approved use of ,

grout in tightly congested areas are controlled to facilitate consolidation of -

the concrete.

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vhN TEL 8/31/79 Pg. 2

2. Very detailed pre-placement planning is carefully performed to identify potential consolidation problems associated with configuration of rebar on embedded items.

Also, Construction and Quality Control personnel identify specific problem-solving methods for use during the placement for expeditious and effective solutions.

Selection of placement size is made based on complexity and inspectability in order to ensure that too large a placement is not made and that controls are applied effectively.

3. Increased attention is given to logistics to provide for back-up equipment, access for inspection, lighting, and manpower assignments to ensure adequate resource availability throughout the placement. The proper use and positioning of vibration equipment during placement is emphasized.

4. The number of Quality Control inspectors assigned to a placement is determined specifically for each placement. Inspectors with the specific duty of vibration inspection are assigned in each case. Construction -

personnel are advised of the inspectors' duties and authority.

5. Special additional training for Construction and Quality Control personnel is given to cover procedures for placement, vibration, inspection, and communication channels to be .

employed during placement activities.

Effective close supervision is mandated to ensure follow-through on planned activities.

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6. Post placement interviews and records reviews are held to ensure that the records accurately reflect the placement activities and certify that the placement is in accordance with procedures and design requirements.

We will discuss these measures in more detail in our upcoming meeting at your offices September 5, 1979.

Very truly yours, f(. 4 . /ev%

EAT:rpv cc: Messrs. M. Borchelt (CP&L)

R. Hancock (COA)

J. Poston (CPS)

G. Oprea D. Barker R. Frazar 1506 332 l

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