Thermal analysis and design features of Muskrat falls RCC North Dam

The Muskrat Falls Hydroelectric Project being developed by Nalcor Energy is located on the lower reaches of the Churchill River, approximately 35 km west of the Town of Happy Valley-Goose Bay in North Central Labrador at latitude of 53° north. It comprises a four unit close-coupled four unit intake-powerhouse structure with a total capacity 824 MW, a gated spillway with a discharge capacity of 25,000 m³/s, a 39 m high overflow roller compacted concrete (RCC) dam and conventional gravity dams to retain the reservoir. The overflow RCC dam, referred to as the North Dam, was constructed over two seasons in a sub-arctic climate with a temperatures range from +30°C in the summer to -30°C in the winter. This paper focuses on the thermal analysis and design features of the North Dam. It presents the dam characteristics, thermal control plan and the thermal protection required during winter as well as temperature monitoring. A comparison of the results of the model and the actual field measurements will be made and variation between these will be discussed.