Yesterday, U.S. federal regulators approved an operating license for Unit 2 of Tennessee Valley Authority's Watts Bar nuclear power plant; it's only taken 19 years and almost 4.5 billion dollars. The Gen II plant should be producing power by the end of the year, and it shouldn't bother you in the least that we mostly stopped building Gen II reactors sometime in the mid '90s.
The Tennessee Valley Authority (TVA) began construction on two pressurized water reactors (PWRs) in 1973. Unit 1 was completed in 1996, while construction on Unit 2 was halted in 1988 when it was 80 percent complete due to a reduction in the predicted growth of power demand. TVA resumed work on Unit 2 in 2007, and it's now gotten approval to load nuclear fuel into Unit 2 and to begin testing. The goal is to generate 1,180 megawatts of power by the end of this year.
Unit 2 (and the currently operational Unit 1) are both Gen II four-loop pressurized water reactors, built by Westinghouse. Generally, Gen II reactors are distinct from more modern Gen III reactors in that Gen III offers improved safety, increased efficiency, and simpler, more reliable designs. For example, four reactors based on the more modern Gen III design, known as AP1000, are currently being built in the U.S. Compared to a Westinghouse Gen II PWR, the AP1000 contains 50 percent fewer safety-related valves, 35 percent fewer pumps, 80 percent less safety-related piping, 85 percent less control cabling, and 45 percent less seismic building volume.
That's a lot less to break down. And when the newer generation's passive advanced safety features are taken into consideration, the AP1000 reactors should be about 100 times as safe as existing plants. If an accident happens, the AP1000 will shut itself down without needing any human intervention (or even electrical power) within the first 72 hours. What's more, only a small amount of water transfer (about ten garden hoses worth) is necessary after that to keep the reactor stable.
Please continue reading from:http://spectrum.ieee.org/energywise/energy/nuclear/first-new-us-nuclear-reactor-in-two-decades-to-begin-fueling-in-tennessee