ML19262C096
| ML19262C096 | |
| Person / Time | |
|---|---|
| Site: | South Texas  |
| Issue date: | 12/11/1979 |
| From: | NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV) |
| To: | |
| Shared Package | |
| ML19262C095 | List: |
| References | |
| 50-498-79-20, 50-499-79-20, NUDOCS 8001280289 | |
| Download: ML19262C096 (1) | |
Text
J 50-498/79-20 50-499/79-20 Appendix A NOTICE OF DEVIATION Based on the results of the NRC inspection conducted during the period November 13-16, 1979, it appears that one of your activities was not con-ducted in conformance with the standard industry practice for the placement of concrete as delineated in AC1 304-73, " Recommended Practice for Measuring, Mixing, Transporting, and Placing Concrete." The observed nonconforming practice is not in full compliance with the conditions of your NRC Construction Permit No. CPPR-128 as indicated below:
Failure to Maintain an Unrestricted Vertical Drop The South Texas Project Final Safety Analysis Report, Section 3.8.4.2.2,
" Specifications and Standards," lists the applicable st$ndards and speci-fications to be used during the structural design, fabrication, construction, testing and surveillance of Category I structures other than the contain-ment.
Item No. 2 on the list is the ACI Manual of Concrete Practice (Part I and II - 1973, Part III - 1972).
ACI 304-73, " Recommended Practice for Measuring, Mixing, Transporting, and Placing Concrete," was adopted as a standard of the American Concrete Institute in April 1973 and included in the Manual of Concrete Practice.
ACI 304-73, paragraph 6.2, " Aggregate and Mortar Separation," states that,
"... Equipment should be arranged so that the concrete has an unrestricted vertical drop into the center of the placement or container receiving it.
The stream of concrete should not be separated by permitting it to fall freely over rods, spacers, reinforcement, or other embedded materials."
In addition, Figure 6.la, " Placing Concrete In Top of Narrow Form," describes the " correct" and " incorrect" methods of properly introducing concrete into a narrow fonn in order to prevent separation of the coarse aggregate from the concrete.
Contrary to the above:
During concrete placement No. MEl-WO43-08A, the IE inspector observed concrete being placed from a plywood chute without the use of a tremie (light flexible drop chute) as shown in the " correct" method of Figure 6.la of ACI 304-73. The placement was a 12 inch wide by 8 feet high interior wall in the Unit I Mechanical - Electrical Auxiliary Building.
The stream of concrete was allowed to strike against a horizontal reinforcing steel bar which ran the length of the form approximately 2 inches above the top of the form. The concrete was placed from one side of the wall only with the plywood chute and a concrete bucket.
This, therefore, offered the opportunity for segregation and could resul't in nonuniform concrete composition.
j g.) {f This is a deviation. 8 00128 o 2.ig )}}