TNAG-1658-FCO40-2306-Daya-Bay-nuclear-power-station-project-safety-concerns-in-Ho-1987 — Page 54

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10 87 11:58 TIBCOOL) HK GOVT JUG SHENZHEN

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APPENDIX 1

VERIFICATION OF TOTAL REINFORCEMENT IN FIRST LAYER

The reactor building raft is built in five layera (see attached diagram), The first layer which contains the non-conformance 10 further sub-divided into a central area with four outer segments.

The various types of reinforcement in the first layer are:

(1) In the central

there is a rectangular mesh of horizontal bara. There are 4 layers of bar at the base and 2 at the top.

(2) In the outer segments there is a radial and circumferential mesh of horizontal bars. There are 7 layers at the base and 4 at the top.

(3) Thara

vertical bars throughout the

protrude from the top.

first layer, all of which

(4) There is the single ring of inclined starter bara which ara the

subject of the non-conformance.

The total number of bare installed with the first layar 1s 14,388 (8,076 vertical + inclined and 6,312 horisontal) and the total weight is approximately 523 Ta. The non-conformance is the omission of 316 inclined atarter bars of a total weight of 9.6 Ta.

bars, and having

Having found the non-conformance in the inclined starter concluded it W&B due to errors in construction management and quality control, it was necessary to re-check all types of ber in the first

the first layer to determine whether any others were affected. This re-check Wad performed separately by HCCM and JVC and was then subject to ап independent audit by JVC QA Department. A further review of the re-check was also made by EdF and a statement obtained from their senior management.

There were several methods used in the re-check. For the vertical bars which protrude from the concrete the check was made directly by comparing the bars actually in place with

with those

those required 00 the drawings. Verification that the lower ends of those bars were correctly placed was obtained from photographs taken during construction.

For the horizontal bars, which are completely embedded, the check Wan made using installation records and photographs taken during construction.

The installation records cover:

F

Details of the preparation of the bars, ie, the cutting and bending.

•

Checks by HCCM during installation of the bars.

Checks by JVC during installation of the bars.

The photographs were takan at various etzges progressive installation of the different types of areas of the raft.

of the work and show the bar in the different