Letters sent as part of the licensing process reveal the Nuclear Regulatory Commission had multiple questions for Energy Northwest about the assumptions it used to develop its response plan for potential accidents. Among the questions: Why did Energy Northwest continue to use 15-year-old studies as the basis for earthquake preparations at the Columbia Generating Station — the Northwest’s only commercial nuclear reactor — when much more up-to-date information about the region’s seismic profile were available from the USGS and Hanford itself? [...]