HEAD.UARTERS
TASK GROUP 7.1
JOINT TASK FORCE SEVEN
Los Alamoe Scientific Laboratory
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J Division, P. 0. Box 1443
:
Los Alams, New Mexico
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Jo1L696L
22 April 1953
TO:
Commander
Joint Task Force Seven
“Nashington 25, D.<C.
FROM:
SeLentifis Deputy
Joint Task Force Seven
Yasningtoa 25, 0. C.
SUBJECT:
LAGOON CONTALINATION AND H&aLTH HaZARDS DURING OPERATICN CASTLE
1. Hecent studies of lagoon contemination snd health nazards frog
radioactive fall-out of Castle have indicated that although tne lagoons
of Bildini and Eniwetok will be contaminated no serious health hazards
will be experienced at tine of re-entry.
2.
(inclosures 1 and 2)
In all provability, ships that re-enter the lagoon following
detonation of atomic devices on the surface or near tha surface will
become contaminated with radioactive materials. The problem that re
sults from this action is the decontamination thet my be naccssiry
at the end of the operation.
‘ater evaporators, wator distribution
aines, and microorganisms adhuring to tho bottom of the snips wil. tend
to concentrate the radioactive asteriale to a degroe tnat U. S. N-vy
shipe my require ecae decontamination at tha complotion of oporations
in order to aset the final clearance standards of 15 atliiroentgens per we
day cs specified by the J. S. Nawal Radiological Safcty Regulaticns cof
1951.
(Por. 8.3)
3.
Pinal Clearance'" as defined in paragraph 25 of the Yandbook
of atomie Voapons for Uediorl Officers (Nav Med Pe1330) “indicatos tnsat
etips, aireraft, and other naterial require no furtner control fro the
etandpoint of radiation." "'OCperational Clearance’ implies tnit con-
tamination exists and special opemting procudures are requircd. “perm
ational cloaranse for ships, aircraft, or heavy oquinmont aay be granted
ty the eommanding officer wien he is assured by the Radiological Savety
Staff that the personnel tolerance Limit will not be exmeeded Sy tneir
ase,"
In the past no time limitation has been placed om tne rate of
accumulation of the total dose (3900 millircentgens per operaticn, since
under this concept, the Scientific Task Group was able to taxo advantage
of tho time intensity factor of radioactive doeay of fission procucts
and ainimisa the tins necessary for the preparation of succouding <coton=
ations. Under sueh a concect, the Naval Task Group may anter ccntacin=
ated lagoons of sevorel hundred mlilroentgens shortly after <stcnat. oA
Inel 2 to TAB “FP”
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