Water Hammer Warning! This alarming letter by Southern California Edison’s Dwight Nunn warned Mitsubishi that its proposed plans for Replacement Steam Generators at San Onofre Nuclear Generating Station could be fatally flawed due to Water Hammers. Unfortunately, the predictions proved to be true. A few years later, on January 29, 2012, San Onofre leaked radiation into the atmosphere. Then they lied about it.