radioactive sources having the same range and proportion of
energies as the fallout material.
DISCUSSION
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j
Decline and fallout composition
It has turned out in practice at Rongelap Atoll that when
a large number of survey meter readings are taken and these are
averaged, a pattern of decline of gamma-dose rates consistent with
the theoretical decay for mixed fission products emerges.
This
is true even though the theoretical curve is based on the decay
of mixed fission products from y735 distributed uniformly over
jan infinite plane and disregards differences in both the compojestion and distribution of fallout radionuclides in the actual
}) field situation.
The fallout at Rongelap consisted of mixed
fission products and neutron-induced radionuclides from a thermonuclear device.
The induced activities contributing to the gamma
activity are of shorter half life than the long-lived fission product, 30-year est 3? ,
It therefore might have been expected that
the early decline in gamma dose rates at Rongelap would have been
more rapid than the theoretical decay of mixed fission products
alone.
As the art of producing thermonuclear
the fission yield per kiloton will decrease.
devices progresses
There will be a
higher proportion of induced radionuclides to FLBSLonecornetas
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