A deactivated reactor from the nation's first nuclear power plant will be floated down the Ohio River in October on its way to a nuclear waste depository in Washington state, officials said. The reactor, to be removed from the deactivated Shippingport Atomic Power Station about 35 miles northwest of Pittsburgh, is expected to be unloaded in February at the Hanford nuclear reservation in south-central Washington. The barge will go down the Ohio to the Mississippi River, into the Gulf of Mexico, through the Panama Canal and up the Pacific Coast. Although the reactor has been emptied of its nuclear fuel, filled with concrete and enclosed in a neutron-shield tank, it's classified as nuclear waste since it has been contaminated by radiation. ``There has never been a plant this large decommissioned in this country,'' said David Ney, a nuclear engineer for the Pennsylvania Department of Environmental Resources. ``It's probably the largest single shipment of nuclear waste in the nation's history.'' Mike Molloy, executive director of Disaster and Emergency Services in Kentucky, said Thursday that his agency hasn't received word of the shipment to Hanford. Mike McKernan, a technology transfer program manager for Westinghouse-Hanford Co., said the company would inform states along the route when the loading date approaches. Westinghouse-Hanford is the federal Department of Energy's technical support contractor for Shippingport. The concrete-filled reactor and its enclosing shield, McKernan said, together about 1,000 tons and measures about 45 feet high and 18 feet across. ``You can stand on it all day long and you wouldn't come in contact with more radiation than if you were standing out in the sun,'' McKernan said. The plant, commissioned in 1957, was the nation's first commercial nuclear power plant. The federal Department of Energy and Duquesne Light, the Pittsburgh-based power company, operated the plant as a demonstration project. They began taking the plant out of service four years ago. By June, the nuclear core was removed and the middle of the reactor, which served as a heat source for water that was converted to steam, was filled with concrete. The Department of Energy is charged with disposing of the reactor and converting the property, owned by Duquesne Light, to ``a perfectly usable condition,'' McKernan said. Pennsylvania officials are monitoring the process.