Water vs. Gas Cooled Reactors: Round 1

In the period from 1966 to 1964, there were two basic reactor choices being offered for commercial electric power production. American companies were offering reactors that used ordinary water under pressure as the reactor coolant. British and French companies were offering reactors using pressurized CO2 gas as the reactor coolant. There were substantial technical differences…

Fuel Element Designs: Unique Selection Criteria

For natural uranium reactors, primary selection criteria is a low neutron cross section. A material that absorbs more than its share of neutrons would prevent the reactor from being able to produce any power at all. After making the coolant and moderator choices, certain other details moved higher on the priority list. Core engineers needed…

Pressure Vessel Construction: Lower Pressure Makes it Easier

In the early 1950s, PWR pressure vessels large enough for a submarine plant were within the capabilities of the existing manufacturing infrastructure, but vessels large enough for electrical power generating stations were not. Like the American pressurized water reactor systems, gas cooled reactors operate at elevated pressures. Unlike water, however, which is kept under extreme…

Letter from the Editor: First Nuclear Power Stations

Interestingly enough, the first industrial scale nuclear power plant for electrical production was Calder Hall 1, a carbon dioxide cooled reactor that began supplying Great Britain in May, 1956. This reactor and others like it have been reliable, long-lived sources of electrical power. In the December 1995 issue we focused on the design decisions made…

CO2: First Choice for Power Reactors

During the period from 1946 until 1954, the single most important constraint governing the development of peaceful uses of atomic power was the Atomic Energy Act of 1946. This American law – passed after a failed attempt to establish an international control regime for nuclear materials – made it illegal to trade in nuclear knowledge…

Protection for Fuel Elements: Ensuring Saftey

Once Rickover’s team selected water as their primary reactor coolant, other material criteria became readily apparent. Though pure water at room temperature is a relatively benign environment, water at high temperatures is quite corrosive. Because radioactive fission products can be dangerous to human health, prudent reactor designers must devise methods to ensure that the fission…

Controlling Power: Temperature and Rods

Pressurized water reactors turned out to be extremely stable power producers. Because of the fact that water is used to moderate the energy level of neutrons, making them more effective in causing fission, the concentration of water in the core is an important part of determining the reactivity of the core. Temperature control An increase…

Technical Hurdles: One Step at a Time

Though water was chosen partially because it was a familiar fluid for power engineers, the choice almost doomed the nuclear submarine program. Laboratory testing of the pumps, bearings, valves, and piping demonstrated to Rickover’s team that the simple, familiar fluid was not so simple at high temperatures and pressures, particularly when exposed to neutron radiation….

Pressurized Water: Best Choice for the 1950s Subs

When Rickover first began studying nuclear technology, he found a program in severe disarray. The Army’s Manhattan Project had accomplished its mission of completing a workable bomb before the end of the war. Many of the key scientists and engineers had left the program, eager to leave the security restrictions and poor working conditions behind….

Prefab Reactors For Off-Grid Users

At the top of Mt. Washington, New Hampshire, for example, electricity for the weather station is provided by a diesel generator using fuel that must be moved by small tanker trucks struggling up a very steep grade. The Army Nuclear Power Program was established as part of the Atomic Energy Commission in 1954. It was…

Army Nuclear Power Plants

Designation Description of Reactors SM-1 This stationary military reactor was the Army’s prototype and training facility. It began operation in April 1957 at Fort Belvoir, VA, several months before the Shippingport reactor. SM-1 has the distinction of having been the first nuclear power plant to be hooked to an electrical grid. 2,000 kw. SM-1A Built…

Letter from the Editor: Portable Nuclear Reactors

The United States Army ran an innovative nuclear power program for more than 20 years. The men involved operated a series of small, nuclear heated generating plants in some of the world’s least hospitable environments. The story of what those diligent heros did has been all but lost. Though the Army was the lead service…