JNR Class AH100

JNR Class AH100
Blueprints
Technical specifications
Manufacturer(s)	N/A
Type of locomotive	Nuclear locomotive
Constructed	N/A
Number built	None
Classification	1-B-B+B-B-1
Dimensions	29,800 mm × 2,650 mm × 3,800 mm
Prime mover	Thermal neutron reactor
Traction motor(s)	MT43 traction motors
Service information
In service	N/A
Number in service	N/A
Preservation information
Preserved	N/A
Number scrapped	N/A

The JNR Class AH100 was a proposed nuclear-powered freight locomotive intended to be operated by the Japanese National Railways.

History

Japan was banned from any form of nuclear research and development post-World War II, but this ban was lifted in 1954 for non-warfare use. To study the feasibility of using a nuclear reactor as a power source, the Japanese National Railways proposed the design of a nuclear-powered freight locomotive, known as the Class AH100, noting that nuclear-powered locomotives were also being discussed in other countries, such as the United States and the Soviet Union.

The feasibility study was published in 1957, noting that while the idea was feasible, it would have been difficult to built a new reactor for this sort of application, as well as numerous safety and technical issues; the report suggested that nuclear research and development be channeled towards nuclear power generation instead.

No Class AH100 locomotives were built, as were any nuclear-powered locomotives.

Specifications

The Class AH100 was intended to be a nuclear-powered freight locomotive, featuring a power output of 2,300 kW (3,085 hp) and 18.5 tons of tractive effort. The locomotive was designed to operate at 50 km/h (31 mph) but could reach a maximum speed of 95 km/h (59 mph). The locomotive weighs 179 tons (394,627 lbs). The locomotive is said to be similar to the Class EH10 electric locomotives and that it was "much bigger than it looked on paper".

The Class AH100 locomotive would have used an enriched uranium-based thermal neutron reactor powering MT43 traction motors rated at 325 kW (436 hp); beryllium was chosen as the nuclear moderator and liquefied lithium used as a heat transfer medium. A special type of steel and paraffin layer would be used as the shield. The reactor had an output of 15,600 kW.

Compressed air heated by the reactor would be sent to a heat exchanger to drive a turbine which turns a generator powering the traction motors of the locomotives.

Trivia

• There is a misconception saying that the AH100 project was conducted in complete secrecy. Despite this, photos of the blueprints have been shown in magazines of the period.