Abandoned & Little-Known Airfields:
Northern Idaho
© 2002, © 2004 by Paul Freeman. Revised 1/04.
Test Area North, Monteview, ID
43.86 North / 112.73 West (East of Boise, ID)
A concept for a nuclear-powered X-6, derived from the Convair B-36.
A Northrop concept for a nuclear propelled bomber, refueling two other aircraft.
The HTRE-3 nuclear aircraft engine, without its test structure.
This is a rather unique case of where an extremely substantial hangar was built,
but never the accompanying runway!
The National Reactor Testing Station (known today as the Idaho National Engineering & Environmental Laboratory)
was established in 1949 in a very remote part of Idaho.
Test Area North was constructed in the early 1950s at the north end of the NRTS property,
about 27 miles northeast of the Central Facilities Area.
It was built by the USAF & the Atomic Energy Commission to support the Aircraft Nuclear Propulsion Program,
an attempt to develop a nuclear propelled bomber.
Beginning in 1955, TAN was the site of the Heat Transfer Reactor Experiments (HTRE),
which conducted ground-based testing of what was intended to be the prototype aircraft nuclear engine.
The aircraft which was intended to use this powerplant was the Convair X-6.
The X-6 was originally intended to be based on Convair's B-36 bomber,
but the design was later changed to use Convair's B-60 (the swept-wing development of the B-36) as its baseline.
The X-6 was intended to have conducted its flights from Test Area North.
A huge (350' wide) hangar to house the X-6 was constructed at Test Area North,
built with enormously thick, nuclear-shielded walls & bays.
General Electric, the program contractor,
planned to equip the engine maintenance facilities with closed-circuit television systems
and remote manipulator arms to allow technicians to work on the aircraft & its powerplant
without direct exposure to the intense radiation field that would persist even after the reactor was shut down.
Since the turbojets essentially functioned as the cooling system for the reactor,
they would have to be run at high power settings even after shutdown of the reactor
in order to maintain cooling airflow through the still-hot core.
After an initial cooldown period, ground cooling systems would be connected to the reactor
and the engines could be shut down as the reactor was extracted from the airplane & placed in its shielded storage bay.
It was estimated that the tremendous weight of a nuclear propelled X-6
would have necessitated a 15,000' runway.
Plans for such a runway were drawn up at TAN, extending to the southwest away from the hangar area,
but the runway was never constructed.
A multi-mile runway for the X-6 was also planned at Edwards AFB, CA,
running between Muroc dry lake & Rosamond dry lake, but it too was never built (see Pancho Barnes Airfield, CA).
The initial HTRE engine experiments were intended to prove out the engineering & operational concepts
for a nuclear bomber powerplant, but without the restrictions on weight & size that an airplane powerplant would demand.
These early assemblies were gigantic monstrosities weighing at least a hundred thousand pounds,
and were built on railcars which would move them to remote test locations
far from their assembly, maintenance & control facilities.
When the engineering aspects of the designs were proven,
the next step would be to reduce the size of the designs while increasing their power output,
with the goal of producing a final, operational version of the design
that would be "flightweight" & "flightsize", with a thermal output of at least 50 megawatts.
This was to be done in stages over a several year period.
Several non-flightworthy prototype nuclear aircraft engines were actually tested at the Initial Engine Test Area,
located at the north end of Test Area North.
HTRE-1, also known as the Core Test Facility, the initial aircraft engine/reactor testbed,
was mounted on a huge mobile railroad car assembly.
It was a water-moderated uranium reactor with a beryllium reflector & shielding that included large quantities of mercury.
The two jet engines just visible at lower left would be started using hot gas produced by chemical-fuel combustors.
Once the jets were running at speed, the reactor would be brought up to power & airflow would be established through the core.
Its heat would then be gradually diverted to the jet turbines as the gas combustor flow was phased out.
The jets would be run on nuclear-heated air for periods of hours at a time
to simulate the operation of a long-duration nuclear aircraft powerplant.
Post-shutdown, the reactor's railcar would be returned to a maintenance bay for disassembly & analysis.
HTRE-1 reached power levels as high as 20.2 megawatts.
General Electric began HTRE-1 test runs in 1955
and the reactor successfully powered the X39 engines the following year,
although the massive contraption was far from a practical aircraft powerplant.
However, HTRE-3 was a major step toward a flight-capable nuclear engine,
which would have been designated XNJ140E-1.
The dimensions of the core & its structural characteristics as well as the design temperatures
were those of a power plant capable of providing useful flight propulsion.
The power generated by HTRE-3 ranged up to 35 megawatts.
In the HTRE No. 3 tests, the power levels were so chosen that the fuel element temperatures, the key parameter,
would be characteristic of flight service.
The size & configuration of HTRE-3 appear to have been designed with the B-36 or B-60 in mind.
HTRE-3 was operated at the National Reactor Testing Station from 1958-60.
Although no aircraft was ever operated under nuclear propulsion,
an NB-36 testbed did fly while carrying an operating nuclear reactor.
These flights were not carried out from TAN, tough.
Having successfully operated a 35 megawatt, flightweight nuclear turbojet powerplant
that probably could have propelled a bomber-sized aircraft,
the Aircraft Nuclear Propulsion project came rather close to fulfilling the original design goals of the late 1940s.
If HTRE-3 had existed in 1952, it most likely would have flown in an aircraft,
but by 1961 the very existence of manned bombers was threatened by the cheaper, faster & relatively invulnerable ICBM.
The large nuclear airplane engine had lost its raison d'etre in the Kennedy/McNamara era,
and the ANP program was cancelled in 1961.
The former X-6 hangar is visible in the top-right of the 1998 USGS aerial photo.
No sign of any accompanying runway is present in photos of the surrounding area.
Today, Test Area North is composed of four areas:
the Contained Test Facility, the Technical Support Facility,
the Water Reactor Research Test Facility, and the Initial Engine Test area.
The Contained Test Facility is located at the west end of Test Area North.
This facility includes the Containment & Service Building (reactor facility),
the aircraft hangar, the Reactor Control & Equipment Building, and numerous support facilities.
Preparation for deactivation of these buildings & structures began in 1996,
and included documentation of some of the historic properties, including the Nuclear Aircraft Hangar.
The Initial Engine Test area is located at the north end of Test Area North.
After the Aircraft Nuclear Propulsion program ended in 1961,
the area was used for the Space Nuclear Auxiliary Power Transient Program through 1967.
Currently, the Initial Engine Test facility is being demolished.
The Three Mile Island Unit 2 reactor core was shipped to the INEEL's Spent Fuel Program area in 1986.
According to INEEL's website, "Unless it becomes necessary for the US to resume former levels of defense-related activities,
the future of Test Area North will consist of completing current programs,
deactivating all facilities, and completing environmental restoration activities."
See also:
http://www.ufx.org/nepa/nepa2.htm
http://titanic.inel.gov:1025/plan/cflup/html/tan.htm
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