A recently completed building to store spent nuclear fuel near Richland, Wash., pushed the concept of high-performance concrete to the limit. Departing from the original mix design, producers lowered cement content, increased fly ash content and added silica fume. In addition, chipped ice was added to control temperature. Truck coordination was the biggest problem. In the end, producer, contractor and owner were all satisfied. Included is ACI's latest attempt to define high-performance concrete. KEYWORDS: high-performance, Hanford, nuclear, silica fume