The PM-3A was a small nuclear reactor that powered the United States’s research base at McMurdo sound in Antarctica. It operated from 1962 till 1972, when a leak was found and the plant was decommissioned.

It is very disturbing to me that a nuclear plant was operated in the Antarctic. This is the most fragile and pristine environment on the planet, and a major accident would have been devastating.

Construction and Instillation

In 1955 the US Navy was given the responsibility of maintaining and supplying the logistical needs of permanent research stations located in Antarctica. Soon after receiving the assignment, the Navy conducted a study that concluded that nuclear power should be considered as the power supply of choice for research stations.

A nuclear power plant would ease the costly problem of transporting millions of gallons of diesel to Antarctica. The study found that the cost of fuel oil for use an Antarctic research station was between $1 and $3 a gallon. A very high price in the late 1950's. On top of transport costs, the cost of storing fuel was high, due to the fact that the fuel required provisions for heating to prevent solidification.

The desire to build a nuclear plant in Antarctica had political motivations as well. The study suggested that an Antarctic reactor would be an excellent demonstration of the President's new "Atoms for Peace" program. It came at a time when the United States had a fascination with all things nuclear, and the federal government was willing to spend millions on any project relating to nuclear power.

The reactor was based at McMurdo Station on the McMurdo sound, one of the most puzzling areas in the world. Though situated in Antarctica, it is barren of snow and ice during the summer. It is believed that this is because of geothermal activity. Established in late 1955, McMurdo station is the largest base in Antarctica, and is the centre of the United States' operations on the continent. It is situated 2 miles from New Zealand’s Scott Base.

The plant was designed, manufactured and assembled by Martin Company (now Lockheed-Martin) for US$4,000,000, and was named the PM-3A. It was the third in the line of portable, medium output reactors. The plant had a net output of 1250 Kw and was designed to be to fit in a C-130 (Hercules) aircraft, but was transported to McMurdo by boat. On top of producing electricity, it also ran a water distillation plant with otherwise wasted heat. It was fuelled by Strontium-90 pellets, one of the most dangerous fuels for a nuclear reactor because of their high radioactivity before it enter the reactor core.

The plant was transported to McMurdo in 1961, and was assembled and tested over the next year. In March 1962, it gained criticality. This was a huge achievement for Martin Company. It had designed, manufactured, transported and assembled a nuclear power plant in less than three years. However, the plant did not prove very reliable in the first few years, frequently losing power. This poor performance, and lack of reliability gained it the nickname “nukey-poo”.

Fuel and Waste

The plant ran on Strontium-90 pellets, one of the most dangerous fuels for a nuclear reactor because of their high radioactivity before it enters the reactor core.

The PM-3A was run under operation DEEP FREEZE, which meant material was transported through New Zealand ports. Most fuel and waste shipments were sent through Lyttleton, New Zealand on US Navy vessels. The ships would stop for 3-5 days before carrying on to Antarctica, or sites in California.

Fuel and waste was often in transit through Christchurch airport. The New Zealand National Radiation Laboratory expressed concern at this, because of the dangers of a plane crashing over New Zealand. If a plane had crashed, the area around the crash site would be contaminated. Due to these concerns the United States agreed to insure New Zealand for any damages resulting from the shipments of nuclear products.

The Leak and Decommissioning

In September 1972, while the plant was shut down for routine inspection, wet insulation was observed around the reactor pressure vessel. It was presumed that this was due to leakage in the shield coolant water piping. Further investigation found that there were cracks throughout the reactor, caused by a failure in some welds.

It was decided that the plant should be shut down and dismantled.

Usually when a plant like the PM-3A is shut down, it is "entombed" (buried in concrete). However this was considered to be inadequate to comply with the intent and letter of the Antarctic Treaty, which states that the area should be left in a close to the original condition in which it was found.

As the United States didn't have regulations regarding how much ground radiation was considered radioactive, the USSR's standard was imposed. This meant that rock and dirt with extremely low levels of radiation had to removed from the Antarctic. In 1976, the USS Towle was loaded with 7700 cubic metres of rock and dirt to be disposed of in California.

The Towle was supposed to dock at Lyttleton, but due to pressure from the New Zealand press it was deferred to Port Charmers near Dunedin.


Archived Files
Antarctic Reactors, 23/20/1, 1954-1976, New Zealand Archives
Transport of Radioactive Materials, 13/5/10, 1954-1976, New Zealand Archives
Nuclear Safety, 16/9/5, 1954-1979, New Zealand Archives

Antarctic Support Associates, Your stay at United States Antarctic Program stations, Englewood, 1996
Foster, M. E. and Jones, G. M., History of the PM-3A Nuclear Power Plant, McMurdo Station Antarctica, Port Hueneme, 1978

PM-3A Design and Construction: Rapid Pace to Fulfill a Need,
A question of Economics: The Answer Depends on the Assumptions,
Antarctic Environmental Awareness Pages,

Newspaper Articles
Christchurch Star, Scientists fear accident at Antarctic Reactor, 10/8/1974
Christchurch Star, No ‘spill’ at Antarctic Reactor, 12/8/1974
Christchurch Star, US Navy’s Dirty Dirt Problem, 12/2/1975

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