Role of electrical problems in the failure of Narora power plant

In the early morning hours on March 31, 1993, a major accident took place in a nuclear power plant located at Narora in Northern India. A huge fire with bright yellow-red flame was seen at both ends of the generator. Extensive damage to the power and control cables and bus ducts took place during this accident. The vertical aluminum ducting above the neutral transformer was completely melted. The ducts ending near the excitation panels had been shattered. All the panels of AVR, Field Breaker and thyristor cubicles were completely damaged in the fire. Mechanical failures include fatigue fracture of Blade No. 52 of the last stage, Bearings No. 4 and No. 5, Generator seals. This paper describes the role of electrical systems in this accident