CHAPTER 17
17.8
CONTAMINATION INGRESS
17.8.1.
Intraduction
If a ship were operating in the base-surge region or in the fallout
zone resulting from a nuclear water-surface or underwater burst, air-
porne radioactive particles could gain access to the ship's interior
through any breaks in the ship's weather envelope. The presence of
radioactive particles would result in radiation fields within the ship,
since the particles might deposit on ship surfaces or remain suspended
in the air within the ship.
In such cases, the means of ingress de-
termines the amount of activity entering the ship, and the access paths
affect the amount of deposition and the concentration of activity suspended in the air within the ship. The conditions under which such
ingress of activity could occur and the interaction of the ship with the
radioactive particles and with the radiations emitted by those particles have been studied at field tests, by the use of simlants, and by
theoretical calculations. Results of these studies will be presented in
17.8.2 and 17.8.3.
The investigation of Ref.8& has indicated three possible breaks in
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a ship's weather envelope that could provide means of ingress of contaminant to below-decks spaces: physical damage to a ship; the boiler-
air system; and the ventilation-eair system. Examination of available
data indicated that the primary effects likely to cause physicaldamage
to a ship operating in the region of a nuclear burst are sirbdlast and
underwater shock. Unlese a ship were at a range close enough to be inmobilized, the deckhous structure and lightly-constructed nonwatertight
doors appear to be the only topside items likely to be damaged by airblast, and such damage would probably not be of sufficient magnitude to
permit significant ingress of activity belowdecks.
Unless a ship is at
such close range that underwater shock causes major hull damage, it is
unlikely that breaks in the weather envelope will result from underwater shock. Therefore, means of contaminant ingress which could be of
significance to operable ships were concluded to be the boiler-and
ventilation-air systems. Results of theoretical calculations and fieldtest measurements of the radiation fields resulting from these two sources
of shipboard contaminant ingress follow.
17.8.2 Theoretical Investigations
In an investigation®’or gamma radiation dose due to contaminated
bottler air, theoretical calculations were made of the dose to boiler-
room personnel due to contaminated air that had leaked through boiler
casinge and idle burner ports into the boiler room of a destroyer.
Bursts of the Shot Baker type, ranging in yield from 20 to 200 KT were
considered. The investigation assumed that the ship was mobile and
that all activity remained airborne. Only external-gamma and inhalation
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