Computational Accelerator Physics Grand Challenge: Accelerator-Driven Transmutation Technologies (ADTT) and Applications

Next-generation accelerator applications have been proposed to solve several problems of national and international importance as summarized below. More information is available at the ADTT and APT pages maintained at Los Alamos National Laboratory.

Accelerator Transmutation of Waste (ATW)

The ATW project offers a solution to the commercial nuclear waste problem by providing for the cleanup and destruction of high-level waste in a safe, economical and environmentally sound manner. In such a system, protons from a high-intensity linac strike a target and produce spallation neutrons which are thermalized and multiplied in a surrounding moderating blanket containing fissionable fuel. Spent commercial nuclear waste is placed in a high flux region where it absorbs neutrons and transmutes to stable or less radioactive material. Steam-generated electrical power is generated from the heat released during the fission process and part of this is used to drive the accelerator. Thus the system transmutes nuclear waste while simultaneously producing electrical power.

Accelerator-Based Conversion of Plutonium (ABC)

The ABC project is similar to ATW but its goal is to reduce excess weapons plutonium resulting from reductions in the U.S. and Russian stockpiles and cleanup of the sites where this material was originally produced. At present there are over 100 tons of this type of material. This constitutes an environmental hazard and a potential danger with regard to nuclear proliferation. ABC provides a safe means of reducing the amount of weapons plutonium.

Accelerator Production of Tritium (APT)

Traditionally tritium for the nuclear stockpile has been produced in nuclear reactors, but at present all these reactors have been shut down. With a half life of 12.3 years, the U.S. tritium supply is decaying. The Secretary of Energy recently announced that the United States will pursue two competing approaches to tritium production: an approach based on the use of existing commercial reactors and a new approach based on APT. In an APT system, a 100% duty cycle, 100 mA proton linac would be used to produce spallation neutrons. These neutrons would in turn be used to produce tritium via the reaction 3He + n -> t+p. Since this does not utilize a nuclear reactor, issues of reactor safety and the generation of very long-lived radioactive waste are not present in the APT concept.

Accelerator Driven Energy Production (ADEP)

ADEP has the potential to provide essentially unlimited energy in a safe and environmentally sound manner. Unlike a conventional nuclear reactor, ADEP uses a subcritical assembly, one that is unable to sustain a nuclear chain reaction unless provided with an external source of neutrons. In this case the system is driven by a proton accelerator that provides the additional neutrons via the spallation process. The use of a driven subcritical system eliminates the possibility of a criticality accident. It also provides a quick shutdown mechanism simply by turning off the accelerator. Another attractive feature of ADEP is that it uses thorium, a fuel in such abundance that it could provide for electric power production for thousands of years. Concurrent with power production in an ADEP system is the burning of its long-lived waste components so that geological storage is not required. Finally, plutonium is not a significant byproduct of the process, which is important with regard to nuclear nonproliferation.

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