Calder Hall and Chapelcross changes in four decades of operation

This paper examines the development of the essential electrical supply system of the Calder Hall and Chapelcross reactors over almost 40 years of operation. The system at Calder Hall forms the main focus of the paper as this is where the majority of development has taken place. The system at Chapelcross has remained largely unchanged but particular developments there are highlighted. The major developments in 1967, 1968, 1979, and 1987-92 are discussed with reference to diesel generator reliability, switchgear, and power supply safety