“f
fos,
limited decontamination operations performed.
3.3
DECONTAMINATION
3 ode 1
Monitoring
Each panel was monitored for beta and gamma radiation
separately at 16 equally spaced points marked on the panel on
approximately a one foot grid. This was done initially before decon-e
tamination operations were begun, after each such operation, and at
the beginning and end of each day, An NRDL designed instrument was
used for mezsuring beta radiation, and the Radiac Training Set
AN-PDR/T1B was utilized for gamma measurements. Beta radiation was
measured directly on the surface and gamma radiation was measured
1 in. above the surface, An instrument mounting jig was attached to
the gamma instrument to insure accuracy of position for all readings,
Background readings were taken periodically for purposes of data
correction.
3.3.2
Decontamination Methods
Each panel was subjected to a variety of decontamination
techniques, applied in the order given below. This order was based
on initial employment of the mildest method known ~ as determined
by previous laboratory investigations - progressing to more and more
severe treatments.
(Economic considerations and limited availa-
bility of space on the test ships precluded the furnishing of a
separate panel for each decontamination operation.) In several
instances two trials were made with identical techniques in an effort
to determine the optimum efficiency of each such technique.
3.3.2.1
Decontamination Methods Employed
a
a.
Low pressure hosing - for a period of 1 minute/panel,
b.
Water scrubbing, followed by a low pressure water rinse,
ce.
Fire pressure hosing, for a period of 30 sec/panel,
(1/4 in, nozzle, with a nozzle pressure of 8 psi).
for a period of 1 mimte/panel.
.
(1/h in. nozzle with a nozzle pressure of 1,0 psi).
ad. Water and detergent (Tide 0.3 per cent solution)
scrubbing, followed by a low pressure water rinse, for a period of
1 min/panel.
e.
High pressure hosing for a period of 30 sec/panel,
(Chemical Corps Decontamination Truck, 350 psi hoce pressure),
£. Hot rinse for a period of 30 sec/panel (Sellers Hie
Pressure Jet Cleaner, 200 psi hose pressure),
Shot 6 panels were treated by applying high pressure hosing
and then water scrubbing (methods "e" and "b" above) only.
Low
contamination and inclement weather precluded additional decontami-~
nation effort, The order of hosing and scrubbing was reversed to
check an observation made during previous panel decontamination to
the effect that hosing seemed inefficient following water scrubbing,
20
CONFIDENTIAL — RESTRICTED DATA
Nd