COMPUTE TIME OF ENTRY INTO A FALLOUT AREA
Critical Task: 031-506-2010
In this lesson you will learn how to compute the time of entry into a fallout area to ensure the least risk
TERMINAL LEARNING OBJECTIVE:
Compute time of entry into a fallout area.
Given information about and illustrations of the procedures for using the total dose
no(cGy) mogram and the M28A1 Nuclear Calculator Set to compute the time
personnel can enter a fallout area when the time of stay, dose rate, total dose, and the
transmission factor are known.
Demonstrate competency of the task skills and knowledge by responding to the
multiple-choice test covering the procedures for computing the time of entry into a
REFERENCES: FM 3-3, FM 3-3-1 and STP 3-54B2-SM.
Immediately following a nuclear burst the radiation dose rate in a fallout area can be very high.
However, for the first few hours, the decay rate of radiation is normally very rapid. For instance, let us
say a nuclear burst has occurred. At H + 30 minutes the dose rate is 4000 cGyph. By H + 1 hour, the
dose rate will be down to 1600 cGyph and by H + 5 hours the dose rate will be down to 235 cGyph.
Armed with this knowledge of radiation decay, a commander can often reduce the amount of radiation
received by personnel by delaying the time of entry into a fallout area.