WPPSS 1 and 4, Washington

In the 1970's, the Washington Public Power Supply System (WPPSS, aka "whoops") began the largest nuclear power plant construction project in U.S. history: reactors 1, 2, and 4 at Hanford, and reactors 3 and 5 at Satsop, west of Olympia. As the budget swelled to $25 billion, and public opinion turned against nuclear power (particularly after Three-Mile Island), the project was cancelled. This resulted in WPPSS defaulting on $2.25 billion worth of municipal bonds sold to finance the project, one of the largest municipal bond defaults in U.S. history. While the collapse of the WPPSS project was by far the most spectacular, it was hardly the only one to be cancelled during that period. Ultimately more than 100 reactor orders were cancelled, including all those ordered after 1973. The Washington Public Power Supply System is now known as Energy Northwest.