TNAG-1658-FCO40-2306-Daya-Bay-nuclear-power-station-project-safety-concerns-in-Ho-1987 — Page 80

TUV

IM

11.24 FIDVVVU/ HN GUVI,

GNPJVC SHENZHEN

Memo to : Executive Committee

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65709

F.04

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3rd November, 1987

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3. Condition 1: Integrity of Other Reinforcements in the First Layer

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Having discovered the non-conformance in the starter rebars, it was necessary to re-check all other types of bars in the first layer to determine whether any others were affected.

By 24.10.1987, the contractor HCCM and the JVC Construction Management (JVC-CM) had separately completed their verifications of the reinforcement in the first layer. These verifications were by of examining the rebar cutting and delivery records, direct counting of the vertical bars protruding from the first layer, and examining the installation records and photographs for horizontal rebars which have been totally embedded. Such verifications concluded that, with the exception of the 316 omitted starter rebars, there was full confidence in the integrity of the firet layer of the raft.

These conclusions were reached by separate assessments made by HCCM and the JVC Project Management. They were subsequently verified and confirmed by an independent JVC QA audit.

Finally, a statement has been obtained from Senior Management in Edr which states that they have full confidence in the methods and techniques used to check the horizontal bars embedded in the concrete and are satisfied with its integrity to proceed with the construction of the next layer.

A detailed description of the verification of the first layer is given in Appendix 1 of this report.

Conditions 2 and 3:

The JVC and NNSA'» Reviews of EdF's Technical Solution

Following detailed design analysis, EdF designers recommended & technical solution which was to place the omitted starter rebara in the second layer and add further reinforcement of about 10 conne in that area such that the rebars are effective in the same way as for che original design. EdF concluded that this technical solution provides a structure which is equivalent to the original design and provides the same confidence in the integrity of the reactor building containment. They also confirmed that they maintain their technical responsibility for the design of this structure.

The technical solution provided by the EdF designers was further endorsed by the General Manager of EdF's Engineering and Construction Division on 29.10.1987.

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