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4
CH3041
URANIUM I
• 235U is 0.7% of natural abundance uranium (the rest
is 238U) and it is the only
naturally occurring,
fissionable nuclide.
• Enrichment
to » 3.5% 235UO2 in nuclear fuel rods is needed for sustained chain
reaction.
Requires chemical transformation into UF6
& then centrifugal separation, more wastes.
& then centrifugal separation, more wastes.
• After use the
rods contain unspent 235U,
238U & 239Pu which must be re-processed.
238U & 239Pu which must be re-processed.
• 239Pu is an artificial radioisotope:
10n + 23892U® 23992U ® 23993Np +b® 23994Pu +b
• 23994Pu is extremely toxic,
radioactive,
t½ = 24 000 y and it is hard to get rid of.
t½ = 24 000 y and it is hard to get rid of.
