Foundation block for turbo-generator of Rajasthan atomic power station

The main features of foundation block design and construction for the twin 220-MW tandem compound turbo-generator sets, one for each reactor of the Rajasthan Atomic Power Station (RAPS) are described. RAPS is situated on the bank of the lake formed by the dam on the river Chambal. The site conditions made it necessary to carry out excavation of hard fissured rock and dewatering 7220 m3 of excavation was carried out. Construction work required 3927 m3 of concrete, 3360 m2 of formwork and 542 tonnes of steel reinforcement. Structural design details of the turbogenerator pedestal and mat which together make the foundation block are given. Factors which were given special attention during construction were maintaining a very uniform quality of concrete, controlled placement temperature, restrictions on welding for splicing large diameter reinforcing steel, close construction tolerances on the alignment for embedded parts, restrictions on construction joints and the use of non-shrinking grouts. Details of formwork, steel reinforcement and embedded parts are presented. Activities of mixing of concrete to meet specifications, its transportation, pouring and grouting of the components of the turbo-generator are described. Points which required strict supervision during construction are mentioned. (M.G.B.)