ML19323F761

Revised Final Deficiency Rept (Significant Deficiency 79-03) Re Crane Wall & Cubicle Wall Reinforcing Bars.Dowels Omitted from Cubicle Will Be Spliced to Protruding Vertical Reinforcement.Concrete Will Be Removed

ML19323F761
Person / Time
Site:	Beaver Valley
Issue date:	05/21/1980
From:	DUQUESNE LIGHT CO.
To:
Shared Package
ML19323F752	List: ML19323F751 ML19323F761
References
NUDOCS 8005290440
Download: ML19323F761 (2)

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FINAL REPORT C,N CRANE WALL AND CUBICLE WALL REINFORCING BARS BEAVER VALLEY POWER STATION - UNIT NO. 2 l NOTE: Revisions are underlined.

1.0

SUMMARY

During the construction of the reactor containment crane wall and a contiguous cubicle wall, forty-eight No.11 reinforcing bars and seventy-eight No. 4 reinforcing bars, as shown on the Engineers' drawings, were -

omitted from a concrete placement.

i 2.0 IMMEDIATE ACTICN TAKEN A Nonconformance and Disposition Report was initiated and all construc-tion work in the vicinity of the affected area was stopped. The Nuclear Regulatory Commission was informed of the deficiency by telephone en  !

November 2, 1979.

i 3.0 DEFICIENCY The reactor containment crane wall is a reinforced concrete cylindrical wall,106 ft. outside diameter, extending from the fourteen columns which support it at Elev. 714'-0" to top of wall at Elev. 815'-5". Its major functions are (1) to provide a support for the polar crane (2) to enclose one side of the three steam generator cubicles and the pressurizer cubicle (3) to provide radiatien shielding for the annular area between it and the reactor containment exterior wall and (4) to support various piping, instrument, and electrical components. Its thickness varies from 2'-0" to 2'-9" with local areas further thickened in the vicinity of major pipe restraints. There are various doorways and openings through the crane wall and integral beams within the wall where required. Full or partial floor slabs frame into and are supported by the crane wall at elevations 718 '-6 ", ' 738 '-10 " and 767'-10".

] Cubicle walls oriented approximately I radially also frame into the crane wall. Below elevation 767'-10", these l 1 cubicle walls vary in thickness from 3'-0" to 3'-3". All of the major components in the reactor containment are located inside the crane wall with the annular area outside the wall being used for access and interconnecting these components.

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. l The area of concern is located between horizontal construction joints at Elev. 755'-10" and Elev. 762'-5", in the crane will between azimuths 970 and 1340 (an are length of about 34 ft.) and in the adjacent cubicle wall for a length of 10 ft. During the construction of this area, twenty-eight 4 No. 11 vertical bars, approximatey 20 ft. long, twenty No. 11 dowels, approximate 1v 12 ft. long, and seventy-eight No. 4 shear bars, approx-in:ately 4 ft. long were omitted. The omission was discovered while preplanning placement of reinforcement for the area immediately above El. '

762'-5".

4.0 ANALYSIS OF SAFETY IMPLICATIONS A review of the design in the area of the nonconformance was performed.  !

The crane wall and cubicle wall sections that include the area where the l reinforcing was omitted have been analyzed twice, once assuming the '

reinforcing as shown on the Engineers' drawings and once assuming the l absence of the omitted bars. These walls were analy:ed as a part of the- i elastic analysis of the pressurizer cubicle using the computer program '

STRUDL. The capacities of the walls for each case were determined in accordance with PSAR requirements.

The results of these analyses indicate that, with the absence of the omitted bars, the remaining reinforcing in this local area would be subject to design stress levels in excess of yield if subjected to one or more of the required loading combinations. Also, the design allowable shear stress carried by the concrete would be exceeded. With all reinforcing in place as shown on the Engineers' drawings, the design stresses remain within allowable limits under the applicable loads and required leading combinations.

A failure analysis was not performed. However, it was assumed that some degree of structural failure might occur under certain accident con-ditions if the omitted reinforcing were not in place.

5.0 CORRECTIVE ACTICN TO REMEDY DEFICIENCY The dowels omitted from the section of cubicle will be mechanically (cadweld) spliced to the protruding vertical reinforcement. The concrete in the area of the crane wall where reinforcing was omitted will be removed as necessary and rebuilt, incorporating reinforcement equivalent to that originally shown on the Engineers' drawings.

Detailed procedures will be developed and/or revised as necessary to implement performance, inspection and documentation requirements rela-tive to removal operations, replacement.of reinforcement and embedments, and concrete placement.

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