TNAG-1658-FCO40-2306-Daya-Bay-nuclear-power-station-project-safety-concerns-in-Ho-1987 — Page 62

NOV 10 '87 12:04 TIBCOOU) HK GOVT

1987-11-04

18:22

P.18

GNPJVC SHENZHEN

65709

P.18

(4)

The effect would be to raise the antire reactor building by 1.2m. There would be many resulting complications because the reactor building is closely linked with surrounding buildings and all would either have to be raised or modified. There would be consequential effect also on the second unit.

Furthermore, the design of the prestressing would be affected since this is located below the raft. If an attempt was made to TALOVA existing concrete to allow the prestressing gallery to be rebuilt at the higher level, the problems noted in point (1) above would arise. If the prestressing gallery was left in its existing position, the and the layout of the prestressing tendons would have to be modified structural design of the containment would be affected (possibly weakened).

be

extent of disruption,

Again, it is not justifiable to introduce this redesign and possible damage if the

possible damage if the building can meet all design ariteria and achieve the HADE #tructural strength 45 the original design using the existing first layer.

To drill into the first layer and insert replacement bars.

*14

This is # method fairly commonly used in civil engineering where reinforcing bars

omitted, and Wed the volution originally proposed by the contractor HCCM.

contractor HCCM. However, the original starter bars include a bend which obviously could not be re-introduced. The contractor's proposal was therefore to use an epoxy grout to fix the replacement bars into the first layer. The high degree of bonding would then compensate for the omitted bend.

Preliminary investigations indicated that this solution would have been technically acceptable and would have preserved all necessary design margins in the final structure. However, the designer, EAF, was asked to consider whether there were any better methods.

(5) To install startar bars in the second layer to compensate for those omitted from the first layer and to add further reinforcement in the second layer such that the bars are effective in the same way as for the original design.

This is the solution recommended by EdF following their analysis. It should be noted that horizontal section of the starter bara in the second layer is longer than that of the startar bars in the first layer. The additional reinforcing in the

the second layer comprises radial bars and circumferential bars and in total corresponds to 10T of additional bars,

Thàn

the preferred solution following JVC's review of ita technical justification.

i