reply to post by cenpuppie
Nuclear-powered aircraft. Good question.
Shortly after World War II, as the US Navy was working on plans for nuclear ships and submarines, the US Air Force (USAAF until 1947) got into the
act with plans for nuclear aircraft. It was more than interservice rivalry -- a strategic bomber with unlimited range was the ultimate fulfillment of
the doctrine of strategic air power. Accordingly, the Nuclear Energy for Propulsion of Aircraft (NEPA) program was initiated in 1946.
In 1947, the Atomic Energy Commission, a United States government agency responsible for the development of nuclear reactors, was created. This
organization would work up the initial parameters for the design of shipboard nuclear reactors for the Navy, and it would absorb the activities of
NEPA as well.
In turn, the commission established the National Reactor Testing Station. It opened in 1949 in a remote location in the lightly populated high desert
country of southern Idaho near the town of Arco.
In 1951, the commission decided that it was theoretically possible to produce a reactor for an airplane. The problem, of course, would be the size
and weight of the reactor, as well as its radiation shield and cooling system. Therefore it would have to be a very large airplane.
Because no one had ever designed a nuclear powered aircraft before, the development process would be methodical, moving step by step. Before a
nuclear powered strategic bomber could become an operational reality, an nuclear powered experimental aircraft would have to be tested as a proof on
concept demonstrator. This aircraft would be built under the designation X-6.
Before the X-6 could fly, however, it was necessary to build and fly a functioning nuclear reactor aboard a conventional aircraft in order to
evaluate shielding techniques.
As a reactor test bed for the eventual X-6, the US Air Force chose the largest aircraft in its fleet, the enormous Convair B-36 bomber. First flown
in 1946, the B-36 was 162 feet long, with a wing span of 230 feet -- a larger wing span than any other military aircraft ever in service in the United
States. It was powered by six Pratt & Whitney R4360 Wasp Major piston engines with 21,000 aggregate horsepower, and later models would also have four
General Electric J47 turbojet engines. Even without the jets, the B-36 could take off with a quarter million pounds of gross weight and fly more than
Early in 1951, as the Atomic Energy Commission undertook the construction of the first airborne nuclear reactor, designated as R-1, the Air Force
ordered Convair to specially modify a B-36 test bed aircraft under the designation NB-36H. Convair was also given the contract to modify a pair of
B-36s that would become the first two nuclear powered X-6 aircraft. The NB-36H would simply fly with a functioning reactor aboard. The X-6s would fly
under nuclear power, with the R-1 reactor powering General Electric turbojet engines. The total propulsion system, incorporating the reactor and
engines, was designated as P-1.
The design of the propulsion system would allow the engines to transition between nuclear power and jet fuel, permitting a conventionally fuelled
take off followed by an extremely long cruise under reactor power. Nuclear cruise would easily permit a flight around the world.
Meanwhile, work was underway to construct a test base for the X-6 program. While the NB-36H flights were conducted from Carswell AFB -- across the
runway from the Convair factory near Fort Worth, Texas -- the Air Force wanted a location for the X-6 project that was farther from the prying eyes of
just anyone. The site chosen for what was to be designated as "Test Area North," was near the small town of Monteview, in the Idaho desert, about 40
miles northeast of the Atomic Energy Commission's National Reactor Testing Station.
The huge hangar that was constructed at Test Area North had thick, lead-lined walls and was designed to contain radiation if necessary. General
Electric moved its nuclear powerplant operations here, and installed robotic equipment so that work could be done on the engines and reactors without
The plan was that the first X-6 flight would come in 1957. The first operational nuclear bomber would, in turn, follow the X-6 in the early 1960s.
The first operational wing of such aircraft was to be in service in 1964. Not only Convair, but Boeing, Douglas and Lockheed were invited to submit
proposals for the development of these bombers.
In 1953, however, the incoming Eisenhower Administration revisited the concept of nuclear powered aircraft and red-lined the X-6 program. The
conventional B-60 program would also get the ax, as the US Air Force chose to acquire the Boeing B-52 instead. Once again, though, the NB-36H remained
a live program, as did numerous feasibility studies for nuclear powered operational aircraft for the future. While the X-6 was not to be the first of
this new breed, the concept of a nuclear powered aircraft remained alive and well.
At Test Area North in Idaho, work on the 15,000-foot runway that was planned for the X-6 program was not begun, but the other work continued. In
1955, the Atomic Energy Commission initiated a series of Heat Transfer Reactor Experiments at Test Area North's big nuclear shielded hangar. These
experiments were part of the ongoing development of airborne nuclear powerplants, but the engines tested were many order of magnitude larger than the
P-1 that had been earmarked for the X-6. The idea was to refine the concept, then scale down the reactor. The goal was a thermal output of at least 50
megawatts delivered by a reactor the size of the one-megawatt reactor that would be test flown in the NB-36H.
Also in 1955, the NB-36H was finally ready for its debut. Except for a completely redesigned nose section, it was similar in outward appearance to a
conventional B-36. Inside was a different story. The gross weight had been pushed up to 360,000 pounds. The one-megawatt reactor itself weighed nearly
18 tons, and the crew shield -- consisting of lead plates and water tanks -- added another 24,000 pounds.
The first flight of the NB-36H occurred on September 17, 1955 and the first top secret flight tests of an airborne nuclear reactor were soon
underway. These missions were considered so sensitive that on every flight, the NB-36H was accompanied by a transport aircraft carrying paratroopers.
Should the NB-36H have crashed, or been forced to land at a civilian airport because of mechanical difficulties, it would be the job of the
paratroopers to surround the aircraft and prevent any unauthorized individuals from reaching it.
During eighteen months of flight testing, all phases of airborne nuclear reactor operations -- from shielding to power output -- were evaluated. When
the NB-36H made its 47th and last flight on March 28, 1957, sufficient data now existed to move ahead to the next phase of nuclear aircraft
Back in the remote Idaho desert, the Heat Transfer Reactor Experiments continued both during and after the NB-36H flight test program. A test reactor
assembly designated as HTRE 1 had been built and first tested in 1955. A water-cooled uranium reactor, it weighed more than a 100 tons and was mounted
on a rail car. It also demonstrated a power output in excess of 20 megawatts.
edit on 25-3-2014 by BillYenne because: Length