POWERGRAMS

34 The last time Jordan Dam's Unit 2 turbine saw the light of day, gasoline was 18 cents a gallon, Harry Truman was president, James Dean got his first break in a Pepsi commercial and the United States sent troops to fight North Korea. History comes full circle sometimes. And it certainly did for a turbine that was lowered into the bowels of Jordan Dam in 1950 as the new wave of cast steel became popular. It was pulled back out for the first time this past January to make way for the new wave of stainless steel. "The first turbines installed in 1928 were cast iron," said Travis Cheaney, superintendent of Jordan Dam. "They had cracking issues that couldn't be fixed." Engineers turned to cast steel, which held up beer under the stress of tons of water flowing through them. But like the predecessor turbines, their day came, too. "These turbines have been subject to cavitation and welding processes for 67 years," Cheaney said. When water hits a turbine blade, it bounces back to the base of the blade behind it, causing extreme stress many times each minute. A look at where each of the 15 blades connect to the boom of the turbine reveals a discolored paern of welds, proving the turbine has seen beer days. Meanwhile, a lucky scrap metal dealer hit the loery, geing 50 tons per turbine from Units 2 and 4. Unit 1 will be shipped to Mitchell Dam and used for turbine welding training. Unit 3 will be replaced in the years ahead. Cheaney said an interesting discovery was made while pulling the three turbines out of the dam. "The condition of the components had changed on each one. It hasn't been consistent," he said. "On one unit, a particular piece may be heavily worn, but not on the others. On the next unit, it was the same thing." The moral of the story: Don't assume the turbines are wearing out the same way or at the same rate. "It proves during outages, we must do a good inspection of each individual unit, and not rely on what adjacent units are doing." Pulling a turbine out of a dam is a major undertaking. "To totally remove the entire unit down to the turbine takes roughly two weeks, working two shis 12 hours a day," Cheaney said. "All the components are removed with the powerhouse (overhead) crane. Once removed, they are rolled into position with a trolley car and lied out of the plant with another crane." A trip below to where the turbine normally is Superintendent Cheaney, Hydro Journeymen Clay Winn and Josh Clark, Summer Plant Auxiliary Austin Rhodes, Hydro Journeyman Andrew Smith and Plant Auxiliary Tom Hoggle Jr. stand alongside old Unit 1 turbine. (Working the night shift and not pictured are Hydro Journeymen Bo Brand and Matt Owens, and Plant Auxiliary Miles Morgan.)

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