With allies in the White House and energy issues on everybody’s mind, the nuclear power industry was on something of a roll this summer. Now, the momentum has shifted. David Lochbaum, a nuclear engineer at the Union of Concerned Scientists, said, "Sept. 11 has been the biggest challenge to nuclear power since Chernobyl." Elected and appointed officials have raised serious concerns about whether a nuclear plant could withstand a plane crash, and at several public hearings, citizens living near plants have expressed similar fears. Meanwhile, the U.S. Nuclear Regulatory Commission has decided not to shut down a nuclear power plant in Ohio, despite concerns that an important reactor safety feature may be cracked. On Tuesday, the NRC said the plant’s owner, FirstEnergy, could continue to run the reactor until mid-February, when the plant is scheduled to come off-line for refueling and safety checks.