ML19253C988

Deficiency Rept Re Ommission of Vertical Reinforcing Steel in Fuel Handling Bldg Wall.Caused by Contractor Oversight. All Omitted Dowels Shall Be Installed in Drilled Holes & Grouted in Place Using Approved Nonshrink Grout

ML19253C988
Person / Time
Site:	Satsop
Issue date:	12/03/1979
From:	WASHINGTON PUBLIC POWER SUPPLY SYSTEM
To:
Shared Package
ML19253C987	List: ML19253C985 ML19253C988
References
NUDOCS 7912120473
Download: ML19253C988 (2)

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Omission of Vertical Reinforcing Steel in Fuel Handling Building Wall 3FHWOO6362.5 10CFR50.55(e) Defect / Noncompliance Report Report Number 008 WPPSS Unit 3 Summary On October 24, 1979 concrete placement number FHWOO6362.5 was completed by Morrison-Knudsen. This placement is an interior shear wall in the Fuel Handling Building of Unit #3. As the vertical reinforcing steel for the next subsequent concrete placement was being set in place it was found that 194 vertical dowels haa been left out of the previous placement. The respon-sibile concrete placement contractor's Quality Control program who has the first line inspection responsibility, overlooked the 194 #11 vertical dowels which were omitted.

Description Morrison-Knudsen, the placing contractor, has an approved concrete placing and inspection procedure #CP-ll which has a concrete place-ment checklist that includes verifying that all rebar is installed properly. This preplacement checklist was signed for final release

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but not for Reinforcing Steel QC Inspection at the time of concrete placement. However, the WPPSS/Eba3co's Concrete Tracking Record, which must be signed prior to release of concrete for placement, was signed by the contractors foreman and QC Inspector indicating all rebar was placed correctly. The contractor could not give any definite reasons for the omission of the subject dowels, except for an error in interpretation of the drawings.

The wall in which the noncompliance occurred is a 7' 6" to 9' thick shear wall that separates the Fuel Handling Building from the Reactor Auxiliary Building. The subject dewels are 11' 0" long straight #11 bars which were to be installed with a 5' 0" embedment langth below elevation 362.5 and a 6' 0" projection abo"e elevation 362.5. This wall serves as a main load bearing shear wall . The design loads exerted on the wall are a combina-tion of earthquake, temperature, slab, and equipment loads. The third row of reinforcing in each face from El. 357.7 to El. 425 is due to tempera *ure loads exerted by the Fuel Fool starting at elevation 383. The structural integrity of the nll would have been adversely impacted had the subject dowels been omitted.

' The cori ractor initiated a Nonconformance Report (NCR #2510) on 10/30/79 and it was transmitted to the Owner / Engineer on 10/31/79.

The NCR identified the dowels which had been omitted. The appli-cable Engineering drawing is 3240-G-2456 R2.

Corrective All of the omitted dowels shall be installed by drilling a three Ac tion inch (3" - 1/2") dianieter hole 4' 6" deep at a location as close to the original design location as possible for each dowel. The omitted dowels shall be installed in the drilled holes and grouted in place using an approved . ion-shrink grout.

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Three additional dowels will be drilled and grouted in a method identical to that stated above for the purpose of performing a tensile pull test on the test dowels. This will verify that the required design tensile strength is being developed and will meet the original wall design criteria.

The following action to prevent recurrence will be taken:

1. Morrison-Knudsen shall be required to change their procedures to require that all drawings applicable to concrete placements surrounding the one being checked out will be reviewed and checked for reinforcing bars and interferences which may impact the placement in question.

2. The contractor shall be required to complete his concrete placement checklist and attach a copy to the Concrete Tracking Record prior to signing the latter.

3. The contractor shall be required to provide a procedural mechanism to verify that all the required bars are installed in the correct location and manner, such as marking up a current set of rebar placing drawings by the QC Inspector.

4. Upon completion of the above three item; a training session shall be conducted with the applicable personnel to assure that the action as stated will be correctly implemented.

These items shall be complete within thirty (30) days of receipt of the NCR with an appaved recommended disposition.

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