19 August 1973
CHAPTER 18
stated in EM-1 that the methodology for calculating total initial radiation exposure as a function of distance from land-surface bursts of
several weapon types, given in Chapter 5, may also be used for water-sur-
face
bursts.
Since # ship's structure forms effective shielding, only
topside personnel could be affected by this radiation.
However, since
initial radiation attenuates rapidly with distance, in only rare in@tances would it have a dominant effect.
‘For instance, it is estimated
that topside personnel could be exposed to the CDC emergency personnel
risk criteria of 150 rad midline dose at about 3000 yd from a 1 MI 100%
“€ission burst.
At such close-in range, other weapon effects are expected
to dominate, as noted in the figures illustrating Governing Effects in
the CDC document, as well as by Hansen and by Klingman.
Residual radiation is produced by radioactive particles in base
surge, Fallout, and in the water.
burst has never been observed.
A base surge due to a water surface
However, it is probable that some radio-
logical debris combines with the water particles that form the columwall
during fireball rise and disintegration.
As a result, a radioactive base
surge should occur as the column walls return to the surface, although the
walls may be so tenuous that the surge would be invisible.
Neither data
nor models exist to ‘predict transit radiation from water-surface bursts.
The fallout from water surface bursts has been observed to return to the
“we
surface very slowly, usually dispersed by the wind, and only low-level
radiations are emitted by the time it reaches the surface (Huebsch).
If
it deposited in ship ventilation ducts or in unwashed locations on deck,
a continuously-emitting source of low level radiation could form below
decks.
Such radiation could produce adverse effects such as fatigue and/
or reduced ability in exposed personnel, but only after a considerable
time had elapsed (ushheve®) BEST AVAILABLE COPY
The water around surface zero is probably radioactive, particularly
within the first hour or so after burst. “Personnel in a emall boat in the
‘water for 1/2 hour or more could be exposed to levels of radiation meeting
or exceeding personnel risk criteria.
18-31