Energy amplifier

In nuclear physics, an energy amplifier is a novel type of nuclear power reactor, a subcritical reactor, in which an energetic particle beam is used to stimulate a reaction, which in turn releases enough energy to power the particle accelerator and leave an energy profit for power generation.

History

The concept is credited to Carlo Rubbia, a nuclear physicist and former director of Europe's CERN international nuclear physics lab. He published a proposal for a power reactor based on a proton cyclotron accelerator with a beam energy of 800 MeV to 1 GeV, and a fuel/moderator target with thorium as fuel and lead as a moderator.

Advantages

The concept has several potential advantages over conventional nuclear fission reactors:

• Subcritical design means that the reaction could not run away — if anything went wrong, the reaction would stop and the reactor would cool down. A meltdown could however occur if the refrigeration of the core were lost.

• Thorium is an abundant element — much more so than uranium — reducing strategic and political supply issues and eliminating costly isotope separation. There is enough thorium to generate energy for at least several thousand years at current consumption rates.

• Less long-lived radioactive waste is produced — most of the waste would decay after 500 years to the level of coal ash. The amplifier could actually be used to transform long-lived waste (like plutonium) from conventional reactors into safer substances.

• No new science is required; the technologies to build the energy amplifier have all been demonstrated in the laboratory. Building an energy amplifier requires only some engineering effort, not fundamental research (unlike nuclear fusion proposals).

• Power generation might be economical compared to current nuclear reactor designs if the total fuel cycle and decommissioning costs are considered.

• Inherent safety and safe fuel transport could make the technology more suitable for developing countries as well as in densely populated areas.

Principle and feasibility

The energy amplifier uses a synchrotron accelerator to produce a beam of protons. These hit a heavy metal target such as lead, thorium or uranium and produce neutrons through the spallation. Thorium nuclei absorb neutrons, thus breeding fissile uranium-233, an isotope of uranium which is not found in nature. Moderated neutrons produce U-233 fission, releasing energy.

This design is entirely plausible with currently available technology but requires more study before it can be declared both practical and economical.