Has Prism cracked it?

PRISM would in truth burn up a fraction of the plutonium used to fuel it

The 600MW(e) PRISM may be loosely based on the 19MW(e) EBR II, but to claim that ‘the (PRISM) technology is proven’ because an experimental unit 1/30th of the size designed in the early 1960’s ran successfully is ridiculous. The huge scale up and the massive shift in nuclear safety standards in the 50 years since EBR II was designed mean that from an engineering perspective PRISM would be an essentially new design, with all the risks that brings. See for example the difficulty AREVA is having with the design and construction of the far less radical EPR development of their existing and successful 2nd generation PWRs.

PRISM would in truth burn up a fraction of the plutonium used to fuel it (although far from all of it). However it would also create a lot of brand new and extremely radioactive fission products, both from the plutonium and the uranium in the fuel. The waste irradiated fuel produced would however, contrary to suggestions in the article, be far more difficult to handle and to dispose of than the existing cans of plutonium oxide.

The article ignores the fact that there is no existing disposal facility for irradiated PRISM fuel, and contains no serious proposal as to what is to be done with it. If we had a suitable disposal site you could put the existing plutonium oxide in it (re-packaged and perhaps spiked), without bothering with PRISM.

It is also ridiculous to claim that the financial risk could be transferred to the private sector. If the company running PRISM was to fail the government would have no option but to take it over.

A far better way of disposing of excess plutonium by burning it in existing commercial reactors, which would require little modification (much of the power produced in existing civil PWRs such as Sizewell B comes from the fission of plutonium created by irradiation of the uranium 238 in the fuel, so adding a bit of plutonium oxide to the new fuel in place of expensive enriched uranium 235 is relatively easy).

Francis Parkinson, Bristol

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