D.

Pearl Harbor Radiological Survey

After arrival at Pearl Harbor Naval Shipyard at 071550 (H+175), the Atomic
Defense Officer

discovered radiation levels as high as 40 mr/hr (ref. 7) and

the crew was "evacuated to the receiving station" (100200) except for special détails.

Subsequent radiological survey (appendix A) revealed the following

general gamma backgrounds adopted here to a reference time of 120900 March, (H

+ 288 hrs).
6

oe

_vhile

Weather decks

Rogge < 5 mr/hr

Ship interior

Rogs < 1 mr/hr

.

.

2

appendix A lists specific items scattered throughout the ship which ex-

‘ceeded these levels, the average dose rates were probably below these levels.

Converting these dose rates to H+] unit reference rates (R, ) gives;

Ry (Deck) = 4.5 r/hr
Ry (Interior) = 0.9 r/hr.
E.

Variation of Dose Rate With Time
Two primary factors can change the dose rate at a given location. First,

radioactive decay which will be estimated by use of equation (2) for each of
the times of interest (see Table 5 below) and; second accumulation or depletion
of activity by physical processes.

Of specific interest here is the effect of

. the weather in removing some of the fallout which is assumed to have been deposited on PATAPSCO at H+32.5 hours.

Table 3 extracted from the PATAPSCO

. deck log summarizes appropriate wind and rain periods during the return trip
to Pearl Harbor.

Select target paragraph3