6.3　Prefabrication of Wall Plates

6.3.1　All wall plates of the absorber shall be prefabricated as shown on the cutting plan in the design drawing.The following requirements shall be met if such cutting plan is not available in the design drawing.

1　All longitudinal joints on wall plates of different rings should be staggered ring by ring in the same direction.The staggering spacing should be 1/3 of the plate length and no less than 500mm.

2　The distance between the longitudinal joint of bottom-ring wall plates and the butt joint of absorber bottom margin plates shall not be less than 200mm.

3　For an absorber with a diameter less than 12.5m，wall plates shall have a minimum width no less than 500mm and a minimum length no less than 1000mm.For an absorber with a minimum diameter of 12.5m，wall plates shall have a minimum width no less than1000mm，and a minimum length no less than 2000mm.

4　The distance between the butt joint of circumferential stiffeners on the outer wall and the longitudinal seam of wall plates shall not be less than 200mm.The distance between the fillet joint（between outer wall longitudinal stiffeners and wall plate）and the longitudinal seam of wall plates shall not be less than 200mm.

6.3.2　The dimensional deviation of wall plates shall be as specified in Table 6.2.5.Positions for dimensional measurement are shown on Figure 6.2.5.

6.3.3　The radians of steel plate arc rolling starting and ending sides shall be controlled.Where necessary，arc rolling shall be performed on both ends using a bed mould.

6.3.4　After prefabrication，each wall plate shall be placed vertically on a horizontal platform for inspection via a sample plate.A linear sample plate shall be used when the plate is inspected vertically，with a gap no greater than 2mm.An arc sample plate shall be used when the plate is inspected horizontally，with a gap no greater than 3mm.