The uncertainty in shine from proximity to contaminated ships is dominated by the

uncertainty in intensity on those ships. Apart from YAG-39 and YAG-40, these vessels were
usually encountered in the Nan anchorage, and thus have a 50-percent uncertainty in the fallout
deposition thereon. With the ship geometries as obtained from Reference 17 and the radiation
transport calculations as validated by the YAG-to-YAG shine data, the overall uncertainty in
average topside intensity from ship shine is also about +50 percent. As the YAG-39 to YAG-40
intensity ratio was consistent to within 25 percent of the mean on 12 of 14 comparisons made from
Reference 13, and the computed ratio was within 20 percent of the observed mean, topside
intensities based on YAGintensities are likely accurate to about +20 percent.
The value for the fraction of time spent on deck is estimated to be accurate within +20
percent for the average crewmember. Forthe typical day, this corresponds to about 8 to 11 1/2
hours on deck. The systematic uncertainty in the time on deck is considered to be greater than its
random variation from day to day and ship to ship. The uncertaintyin total dose is reasonably
high-sided by treating the uncertainty in time on deck as a systematic error; as such, the #20
percent applies to all topside contributions to the total dose as well. Actually, only for the dose
from fallout is the topside time fraction the leading quantified uncertainty. For shine, the typical 50
percent uncertainty in source intensity dominates. While the intensities on YAG-39 and YAG-40
were more accurately known, the brief exposures to them limit the applicability of long-term
estimates of uncertainty in time spent topside. Thus, no such uncertainty is quantified for a typical
MOLALAcrewmember.
The ship-shielding factor reduces the below-deck crew exposure to fallout to a minor
contribution to dose, thus any realistic error in that parameter has only a few-percent effect on the
total dose. For example, for a typical day (60 percent below deck) and a ship-shielding factor of
0.10, with an error generously assumed to be +0.05, the fractional error introduced is
[0.60(0.05)} / [0.60(0.10) + 0.40(1)] = 0.065. Such values negligibly increase the uncertainty in

dose resulting from uncertainty in time spent topside.
Reference 1 investigated the impact on the spatial variability of topside intensities on the
distribution of crewmember doses. While data from YAG-30 and YAG-40indicated considerable
variation in readings across ship decks, the overall impact on personnel dose was small--about 10

to 20 percentfor the ships analyzed in Reference 1. The distribution in personnel dose from this
source for the ships ofthis report is likewise small. Wider distributions of personnel dose can be

attributed to individual or rating-related variationsin the time spent topside. An extreme example is
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