Although Wall Street analysts expressed concerns about the economic viability of the aging nuclear fleet in the U.S., the recent early retirements of four nuclear reactors has sent a shock wave through the industry. One purely economic retirement (Kewaunee, 1 reactor) and three based on the excessive cost of repairs (Crystal River, 1 reactor, and San Onofre, 2 reactors), in addition to the cancellation of five large uprates (Prairie Island, 1 reactor, LaSalle, 2 reactors, and Limerick, 2 rectors), four by the nation’s large nuclear utility, suggest a broad range of operational and economic problems.