CHENNAI: The city corporation is set to upgrade the infrastructure of corporation schools at an estimated project cost of Rs 61.7 crore. Following an announcement in the Assembly by Municipal Administration Minister KN Nehru, work orders have been issued for six corporation schools at a cost of Rs 17.3 crore. Tenders have been floated to upgrade eight other schools at an estimated cost of Rs 21.7 crore, said a statement from the civic body on Tuesday. Project estimates are being prepared for another 12 schools, and tenders would be floated once the estimates (about Rs 22.5 crore) are finalised.