7.5 Assembly of Wall Plates
7.5.1 Prefabricated wall plates are subject to dimensional and visual re-inspections prior to assembling.No assembling is allowed unless the plates are found acceptable.Where rectification is necessary，hammer mark on the plate shall be avoided.
7.5.2 For down-up or upside-down installed wall plates of the first ring shall meet the following requirements；
1.The horizontal deviation of the upper edges of two adjacent wall plates shall not exceed 2mm.The horizontal deviation of two points randomly selected on the circumference shall not exceed 6mm.
2.The vertical deviation shall not exceed 3mm.
3.After welding，the diameter deviation at any point on the inner surface of wall plates at a height of 1m shall not exceed 0.1% of the diameter of the absorber body，and the maximum deviation shall not exceed 10mm.
7.5.3 The verticality deviation of wall plates of rings other than the first ring shall not exceed 0.3% of the height of wall plates of the corresponding ring.
7.5.4 Where no detailed requirements are provided in the drawing，the assembly gap between butt joints in wall plates shall be as indicated in Table 7.5.4-1 and Table 7.5.4-2.
Table 7.5.4-1 Assembly gap between circumferential butt joints in wall plates（mm）
Table 7.5.4-2 Assembly gap between longitudinal butt joints in wall plates（mm）
7.5.5 When wall plates are assembled，the internal surfaces shall be flush，and the off-set of butt joints shall be as specified below：
1 Off-set of longitudinal butt welds：
The off-set shall not exceed 1.0mm if the plate is less than 12mm in thickness.The off-set shall not exceed both 1/10 of plate thickness and 1.5mm if the plate is not less than 12mm in thickness.
2 Off-set of circumferential welded joints：
The off-set of any point shall not exceed 1.5mm if the upper ring wall plates is less than 8mm in thickness.The off-set of any point shall not exceed 1/5 of the plate thickness and shall not exceed 2mm if the upper ring wall plates is not less than 8mm in thickness.
7.5.6 After the assembly，the angular deformation of longitudinal welds shall be checked by a 1m-long arc sample plate，and the angular deformation of circumferential welds shall be checked by a 1m-long linear sample plate.The results shall comply with Table 7.5.6.
Table 7.5.6 Angular deformation and local unevenness deformation on absorber wall welds（mm）
7.5.7 After assembly and welding，local deformations on the absorber wall shall be gentle，free of abrupt fluctuations and conform to the requirements in Table 7.5.6.
7.5.8 As one absorber section，each assembly section of three rings shall be evaluated after the assembling，including measuring diameter，verticality，levelness and elevation of each absorber section.
7.5.8.1 Diameter
A total of 8 to 12 equal diversion points shall be taken on the circumference of the absorber section for diameter measurement.The permissible diameter deviation shall be 0.1% of the internal diameter of the absorber body，and shall not exceed 12mm.
7.5.8.2 Verticality
A total of 8 to 12 equal diversion points on the circumference of the section shall be taken for measurement.The permissible verticality deviation shall be less than 0.1% of the section height，and shall not exceed 15mm.
7.5.8.3 Levelness
A total of 8 to 12 equal diversion points on the circumference of the upper edge of the section shall be taken，with a permissible levelness deviation of 3mm.
7.5.8.4 Elevation
A total of 8 to 12 equal diversion g points on the circumference of the upper edge of the section shall be taken.The permissible elevation deviation shall be 0.1% of the height of the section，and shall not exceed 25mm.