From Artur Knoth
Regarding the new Japanese design for a small nuclear reactor, I beg to
differ with the assessment of one of the “experts” stating that there was
nothing wrong with the basic design
(25 August, p 4).
Molten sodium cooling systems have a “weeping” problem, where the fluid tends
to squeeze through even the finest micro-cracks in materials. Whenever this
cooling material encounters water, the reaction is violent and explosive.
Also, less than 10 per cent of natural lithium is the isotope lithium-6. This
would require costly isotopic separation from the more common lithium-7.
Lithium-6 is used in nuclear bombs and if it got into the wrong hands could be
as dangerous as enriched uranium and reactor plutonium.
When lithium-6 captures a neutron, it can decay into tritium and helium.
Tritium is radioactive and can easily enter biological systems in water.
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I’d say there’s quite a lot wrong with the concept of a small nuclear
reactor, and without stringent safeguards it could become an environmental and
proliferation hazard of the first order, especially in a country subjected to
numerous earthquakes and typhoons.
Immenstaad, Germany
