8/14/2019 IV Introducing TWR 3-6-09

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The Future of Nuclear Energy

Intellectual Ventures has launched an eort to design nuclear energy reactors that improve on those in operation today. Knownas TerraPower, the project has produced preliminary designs or a new class o nuclear reactor, called a Traveling-Wave Reactor(TWR). The TWR can run or 50 to 100 years without reueling or removing any used uel rom the reactor. By greatlysimpliying the nuclear uel cycle, TWRs could improve the cost, saety, social acceptability, and long-term sustainability onuclear energy as a source o emissions-ree electricity.

The ScienceNuclear power plants produce electricity rom the heat

generated when big and unstable atoms, such as plutoniumand the rare orm o uranium called U-235, split apart intosmaller atoms. Each time a big atom splits (or ssions), itreleases ast-moving neutrons and other subatomic particlesthat leads to a chain reaction.

A nuclear reactor produces and controls the release oenergy rom splitting atoms o certain elements. Nuclear

electricity plants today use uel made rom naturaluranium that has been enriched. The TWR, in contrast,initially contains only a small igniter o ssile uel, whichis used to kick o the chain reaction. The wave o ssionwould move slowly through the core, splitting many moreo the uel atoms than a conventional reactor would.

A TWR reactor core would be lled with uel that ismade out o atoms that are big but not unstable enough tocause a chain reaction on their own. The uel could be de-pleted uranium, or example, which is the common U-238orm o the element that is currently set aside as waste whenU-235 is taken out o natural uranium at enrichment plants.

1979Michael J. Driscoll andothers at MIT urtherevaluate breed-burn

reactor ideas

2000Hugo vanDam publishesmathematical analyses

o waves o fssionmoving insidenuclear uels

1996Edward Teller, Lowell Wood (nowat Intellectual Ventures), andothers at Lawrence Livermore

Lab detail ways to make breed-burn waves travel through astationary uel supply

2006Intellectual Venturesbegins detailed physicsand engineering studies

o the easibility, cost,and eatures o variousTWR designs

The Evolution of the Traveling-Wave Concept

1958Savelii M. Feinbergproposes a breed-burn reactor in which

unenriched uel ismoved around the coreto sustain fssion

Early 2000sHiroshi Sekimotobegins a series oconceptual studies o

various kinds o TWRs

Neutron

Fissionproducts

+

+

23.5mins

2.

35DaysU

Pu

1An atom o ertileuranium captures aast-moving neutron,which converts theuranium to a heavier,unstable orm.

2 The atom quickly decaysinto a orm o neptuniumthat is also unstable.

4The neptuniumeventually decays into anatom o fssile plutonium.

3 The plutonium fssions intosmaller atoms, releasing lots oenergy and several neutrons,some o which continue thechain reaction.

Breeding Fissile Fuel Just Where It Is NeededDepleted uranium is converted rom its normal ertile orm into fssile plutoniumin the region just ahead o the burning wave.

Introducing

TravelingWave Reactors

Many Shapes and SizesTerraPowers scientists and engineers are investigating a

wide range o designs or TWRs. Small, modular units thatgenerate 100 megawatts o electricity may be easible andcould t the needs o emerging markets. Conceptual designsor gigawatt-scale reactors, big enough to power a city andsimilar in outward appearance to existing plants, are wellunderway. And TerraPower is studying and simulatingmany other varieties. At Intellectual Ventures, the process oinvention continues every day.

A Simpler, Safer Fuel CycleUnlike light water reactors, the TWR can theoretically run

orever without ever needing any additional enriched uraniumater its startup period. This feet could supply the worlds needsor energy or thousands o years without any need or chemicalreprocessing o the used uel. This ability is a major advance inreducing the inherent risks o weapons material prolieration.

or press inquiries: TerraPowerInfo@intven.com