Breeder FAQs

What is breeder?

Pieces of natural uranium metal placed in a special zone around the core of a fast neutron reactor.

What was its purpose?

The production of nuclear fuel.

How?

The natural uranium absorbs neutrons from the core fuel and changes into plutonium.

What was the plutonium needed for?

Britain in the 1950s wanted to build nuclear power stations to regenerate the country. But the country didn't have enough nuclear fuel.

Fast breeder reactors offered the prospect of power stations that could convert an otherwise useless form of uranium into plutonium that could be used as new fuel.

Dounreay was the experimental design.

What does it look like?

Each piece of breeder is shaped like a cylinder, approximately 15cm in length and 35mm in diameter, and is known as a “puck".

How much do you have?

Fourteen “pucks” normally were laid end to end in a steel tube, 2.4m in length and known as an element. The elements were positioned vertically around the core.

There’s 977 elements in a rack around the core and another 200 in storage at the site.

They weigh a total of 44 tonnes.

Is it all plutonium?

No. Typically, about 0.2 per cent of the natural uranium metal will have turned into plutonium metal while exposed to neutrons inside the reactor.

How do you recover the plutonium?

The "pucks" are dissolved in acid in a chemical separation plant. The different metals are separated chemically and converted back to solid metal.

Has this been done before?

Yes. Thirty tonnes of breeder material was removed from the experimental reactor between 1967 and 1972 and sent to England for reprocessing.

How hazardous is it?

The breeder is radioactive, but less so than conventional reactor fuel. The type of radioactivity emitted by plutonium is less penetrative than conventional fuel from a reactor.

Who owns it?

The Nuclear Decommissioning Authority, on behalf of the UK Government.

Can you keep it at Dounreay?

If it was considered waste, yes. But the plutonium is a fuel that can be recovered to generate electricty in the future, so we are packaging it in a way that allows the NDA to remove it from the site. Dounreay doesn't have the facilities to recover the plutonium.

Could you keep it in the reactor?

No. It must be removed in order to decommission and make safe the reactor.

Has a decision been taken to remove the breeder from Dounreay?

Yes.

The NDA consulted in 2010 on its strategy for the co-location of nuclear materials at certain sites, and this project was identified in its draft business plan issued for consultation in December 2010.

In summer 2011, NDA announced its preferred option to remove the breeder from Dounreay. This was confirmed by NDA in November 2011.

How much is this costing?

We expect the removal, processing and export of all the breeder from the site to cost in the region of £100 million.

Is this material a security concern?

Yes. We are working very closely with the Office for Nuclear Regulation, the nuclear security regulator, and the Civil Nuclear Constabulary to protect this material at every stage of its journey.

How and when will it be transported?

We expect the breeder to begin leaving the site in summer 2012 and be transported by rail to Sellafield.

Will you announce details about where and when it will be transported?

No, for security reasons.

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