ML19276H125

Applicants' Prepared Testimony Re Containment Concrete & Related QA for Public Hearing in Harrisburg,Pa

ML19276H125
Person / Time
Site:	Three Mile Island
Issue date:	10/25/1973
From:	METROPOLITAN EDISON CO.
To:
Shared Package
ML19276H123	List: ML19276H122 ML19276H124 ML19276H125 ML19276H127 ML19276H128 ML19276H130 ML19276H131 ML19276H132 ML19276H133 ML19276H134 ML19276H135
References
NUDOCS 7910100539
Download: ML19276H125 (7)

Text

- Oct )ber 25, 1973 UNITED STATES OF AMERICA ATOMIC ENERGY COMMISSION Before the Atomic Safety and Licensina Board In the Matter of )

)

METROPOLITAN EDISCN ) Docket No. 50-289 COMPANY, et al. )

)

(Three Mile Island Nuclear )

Station, Unit 1) )

APPLICANTS' PREPARED TESTIMONY PELATED TO CONTAINMENT CONCRETE AND RELATED QUALITY ASSURANCE

1. Introduction The overall quality assurance program, as described in Section 1.6 of the TMI Unit 1 FSAR, has been applied to construction of the containment building, including its ring girder, as well as other areas of plant construction. This quality assurance program complies with 10 CFR Part 50, Appendix B. The specific aspects of this program of particular importance to control of structural concrete construction of the containment and ring girder are summarized in subsequent sections of this testimony. The program included development of quality standards, implementation of the quality stancards by means of detailed procedures and performance of numerous inspections 1417 080 7910100 N

s and tests. It is considered that this quality assurance program led to obtaining a h4,.i quality containment building and ring girder which is in complete accordance with the applicable specifications.

2. Quality Standards The quality assurance program provided for specifying the technical and quality standards that had to be satisfied for all work important to safety before the work could be considered complete. Accordingly, the technical and quality standards applicable to the containment building and ring girder structural concrete, which are described in the TMI Unit 1 FSAR, were specified in Gilbert Associates, Inc., Specification for Structural Concrete, SP-5406. This Gilbert Associates' specification was issued on December 4, 1967, prior to start of work on the containment building by United Engineers and Constructors (UE&C). It required the quality control to be based on the requirements of ACI 301-66, Specifications for Structural Concrete for Buildings, which is the recognized industry standard for structural concrete. Further, although ACI 301-66 does not make it mandatory to comply with related ACI recommended practices such as for cold weather and hot weather concrete processing, ASTM specifications for ready-mixed concrete, and applicable ASTM specification for materials and testing, all of these were in fact follcwed in order to ensure high quality.

1A17 081 The most important of the specifications and codes applied to the containment building and ring girder are as follows:

A. Gilbert Associates, Inc., Specification for Structural Concrete, SP-5406.

3. American Concrete Institute, Specifications for Structural Ccncrete for Buildings , ACI 306-66.

C. American Concrete Institute, Building Code Requirements for Reinforced Concrete, ACI 318-63.

D. Commonwealth of Pennsylvania Department of Righways Specification, 1960 Edition.

E. Specifications for Ready-Mixed Concrete, ASTM C94-67.

F. Numerous ASTM material specifications, ASTM testing methods, ACI recommended practices, etc., as specified in the UE&C Quality Control Procedure No.1, General Construction and Quality Control Procedures for Structural Concrete.

It should be noted that these codes and specifications are generally consistent with those specified in a recent AEC regulatory guide (1.55) and in a recent draft industry standard (. ANSI M45.2.5) for nuclear power plant 1417 og2 structural concrete, even though the codes and specifications for TMI were developed long before the AEC guide or industry standard were developed.

3. Procedures At the start of the TMI project, concrete in the initial placements in the containment building base mat failed to meet specifications. As a result, all of the deficient concrete in the base mat was completely removed and a detailed quality control and construction procedure (QC-1) was developed and implemented to ensure that a high quality of structural concrete would be achieved. This procedure served to ensure high quality by requiring detailed inspections and tests of concrete work to be performed as described in the next' section. These tests and inspections were intended to minimize the likelihood of further problems occurring during placement of concrete and, of equal importance, ensure that any problems which did occur were detected and corrected.

In addition to the basic quality control procedure, QC-1, two other construction procedures were followed to ensure control of related construction work. These are as follows:

A. UE&C Civil Construction Procedure CCP-1,

" Erecting Tendon Conduit System in the Reactor Containment Wall and Dome".

1A17 083

-4_

B. UE&C Civil Construction Procedure CCP-6, "The Pump Placement of Concrete".

The quality control checklists for these procedures specified the tests and inspections to be performed to ensure that these activitiec were properly performed.

Despite the use of the above precautions ,

occasional errors in concrete placement did occur, but these were detected by quality control and corrected. The most significant problem in this regard involved voids and foreign material in the ring girder. This problem was detected and documented by quality control during placement of concrete in the ring girder and was confireed upon removal of the concrete forms. A detailed procedure for repair of the ring girder was developed, CCP-9, " Containment Ring Girder Repair" which included detailed requirements to ensure that the quality of the finished ring girder is satisfactory. This procedure was reviewed in detail with the AEC.

4. Quality Control Tests, Inspections and Records In accordance with the specification and as detailed in the Quality Control Procedure, QC-1, numerous tests and inspections were performed related to concrete placement, and appropriate records of these were generated.

The tests, inspections and records are summarized in the follcwing paragraphs.

An on-site testing laboratory was used for concrete materials and compressive strength testing and an on-site l'!l7 084

_3

batch plant was used for concrete production. Quality control records were kept on file for each load of concrete placed in the containment building and cover the location of the pour, the actual batch proportions, concrete slump and temperature, and total number of mixer revolutions.

Concrete compressive strength cylinders were cast for every 50 cubic yards of concrete placed in the containment building and cylinder strength test results recorded.

Other reports of quality control activities related to concrete placement include concrete placement check-out sheets, inspectors' ccncrete check-out sheets and concrete status reports, reports of concrete placement and daily concrete curing records. These records demonstrate that quality control inspections were performed for all contain-ment building pours. Results of tests or inspections that did not meet specification requirements were reported to the constructor, UESC, for appropriate corrective action.

Discrepant conditions were resolved by rejection of materials or loads of concrate that did not meet specification require-ments and by repair of portions of the structure that did not comply with project specifications.

In regard to inspections and tests of the ring girder repair, the normal requirements of QC-1, as described above, applied and, in addition, the numerous additional inspections and checks called out in the QC checklists to procedure CCP-9, Containment Ring Girder Repair, were

!4i7 085 performed. These included documented checks to ensure that all defective concrete had been removed, imbedments were properly installed and/or repaired, concrete placement preparations were satisfactory, concrete placement was controlled, and proper curing conditions were maintained.

5. Stress Analysis As described in the December 9,1971, Met-Ed Report, as amended, " Report on Contaiament Building Ring Girder Construction and Repair", an extensive stress analysis of the ring girder was performed to determine if the repairs could have any detrimental effect. This analysis concluded that the repaired ring girder would fulfill the original design intent and all the requirements in terms of service, durability and safety.

6. Post Construction Tests and Monitorine Subsequent to construction of the containment and ring girder, the tendons have been stressed. Extensive measurements taken during this tendon stressing demonstrated that the structure was sound.

During the plant test program, and prior to fuel loading, the contain%ent bui?. ding and ring girder will be subjected to a structural integrity test at 15% above the design pressure associated with the maximum hypothetical accident.

1417 e~0 J0 I