The US Department of Energy is backing off an internal memo which suggested the government could break a promise to Nevada over the timing of radioactive-waste shipments. A spokesman at the Energy Department's Fernald cleanup site near Cincinnati said today the internal memo mistakenly suggested that the government could violate its promise to give Nevada 45 days notice of the waste shipments. Spokesman Gary Stegner said the memo was corrected yesterday and the commitment to give the advance notice will be honored. Energy Department officials in Washington gave Nevada the commitment last month after that state threatened a lawsuit to block the planned radioactive waste shipments. The Energy Department plans thousands of truck shipments from Ohio to Nevada starting this summer to fulfill a commitment to environmental regulators to finish cleaning up the Fernald site by 2006.