Even before World War II, the U.S. Navy was eyeing nuclear energy as a power source for long-range submarines. After the war, the Air Force, too, focused on a nuclear-powered dream machine: a bomber capable of remaining aloft for weeks at a stretch. In 1949 the AEC authorized ORNL to design its reactor power plant.
The nuclear plane posed two formidable challenges, recalls engineer Don Trauger, who marked his 50th year of Oak Ridge work in 1992: Could a reactor manage to loft a plane laden with bombs, crew, and--mainly--itself and its shielding? And given the impractical weight of conventional shielding--7 feet of concrete--could the crew survive the radiation exposure?
To study the shielding problem, two reactors were built, says Trauger. Beginning in 1950, samples of various shielding materials and thicknesses were bombarded with radiation in ORNL's new Bulk Shielding Reactor. To explore the airborne reactor's shielding design when aloft and removed from neutrons reflected by Earth, ORNL built an unshielded reactor and hoisted it, by cables slung between steel towers, to heights of 200 feet or more.
For propulsion, ORNL engineers adopted a novel design: a high-temperature ``fireball'' reactor fueled by molten uranium salts. A 1-megawatt model made a 100-hour test run in 1954, witnessed by Captain Hyman Rickover, General James Doolittle, and Admiral Lewis Strauss, head of the AEC. Next step: a full-scale, 60-megawatt reactor, which Trauger was to operate. ``It was called a fireball,'' Trauger says, ``and it was. It was to run red hot.''
Before the full-scale reactor could be built, the nuclear plane--freighted with technical, financial, and political baggage--was grounded in favor of ballistic missiles. ``Fortunately, it was never completed,'' says Trauger. ``The nuclear aircraft was a big, difficult, complex system that presented unacceptable hazards to friend as well as foe.''
``All we had to do was get it into the air over enemy territory,'' he laughs. ``They'd dare not shoot it down.''
The AEC scrapped the program in 1957. But the pie-in-the-sky idea laid down-to-earth foundations in reactor fuels, materials, computing, and other areas still being built on today.
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Date posted 5/10/94 (cel)