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DNA 1240H-2
No contamination-ingress measurements were made at Operation Redwing.
2.
UnderwaterBursts
Operation Crossroads, Shot Baker: Ali ventilation-system
Openings on target ships were sealed prior to Shot Baker.
However,
damage to the cover (an opening about 6 inches square) on the ventilation system for the after engincroom of USS CRITTENDEN (1686 yd from
surface zero) permitted entry of contuminant.
Eighteen monthe after
Shot Baker, the dust in the contaminated ventilation system was recovered and analysed.
Fission products equivalent to 115 microcuries
of radioactivity were recovered from the dust at that time, and it was
calculated, from radiochemical analysis and fission-product decay schemes
that about 370 curies of radioactive aerosol entered the ventilation
system from the base surge.
The ship was, of course, rendered immobile by the burst, and was enrulfed by the base surge for about 14
min.
Thue, 6 significant amount of contaminant gained ingress through
the small break in the weather envelope.
Operation Hardtack: At Operation Hardtack,
several projects were
concerned with shiphoard ingress of contaminant, 33;®and the effects at
below-decks locations.
Three ventilated compartments were instrumented
On the moored and washed DD-592.
Conditions simulated the operational
condition of blowers OFF, but no closures were used in the ventilation
system.
Measurements were made of contaminant ingress in (1) the galley,
(2) the after engineroom, and (3) the after crew's quarters.
In addition,
fullpower airflow was maintained through an unfired boller in the after
fireroom, which was also instrumented.
The destroyer was moored with
ite starboard side to surface zero, 3000 ft downwind during shot
Umbrella, and 4900 ft downwind during Shot Wahoo.
Two other destroyers
(DD-474 and DD-593) were also moored downwind with their sterns to sur-
face zero.
The forward firerooms of all three destroyers were instrumented with film badges and recording radiation detectors, and one
boiler was fired with an airflow of about half the fullpower airflow.
The following table, taken from Ref.33, summarizes the conclusions on the
probable paths of activity ingress into instrumented compartments.
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