time in the sample, the results appear in Figs. 36 to 38.
Thus Fig. 36 would be read as
follows: at no time in the sample did the areas outside the zero contour receive fallout;
at no time did the area between zero and the 500-r contour receive more than 500 r,etc.
‘Figure 37 would be interpreted in the same manner: for 70 percent of the days in the sample
the area outside the zero contour was fallout free; for 70 percent of the days in the sample
the area between 0 and 500 r received less than 500 r (conversely, 30 percent of the time it
TABLE 10
TARGETS AND NUMBER OF WEAPONS
tn Mock WiIpESPREAD ATTACK
Target
|
Allentown-Bethlehem-Easton
Baltimore
Harrisburg-Lancaster-York
Johnstown-Altoona
New York-NE New Jersey
Norfolk-Portsmouth-Newport News
Philadelphia
Pittsburgh
ding
Scranton—Wilkes-Barre
Trenton
Washington, D.C.
i
4
Wilmington
Wheeling-Steubenville
received more than 500 r), ete.
Weapons
met bt et ee ee TN OS
nea teAe eees ee eecee anime
ee
Eete ohn th ee
a ae
{
CONEIDENTLAL
Figure 38 would be similarly read, and, since it shows
the conditions that would exist 50 percent of the time, represents the median case.
findings hold several implications for selection of a civil defense tactic:
These
(a) If planning is to be done at the 100. percent confidence level (no possibility of a
given level of radiation being exceeded based on the present sample), movementto the north
and east and short movement to the south is precluded, since these areas at sometime
receive cumulative 2-day radiation doses in excess of 2300 r. Movement of approximately
25 miles to the west places evacuees in relative safety (50 to 250 r, 0.5 attenuation) and
movement to the south and west of 125 and 225 miles, respectively, places them in falloutfree areas. However, due to limitations in direction of movement and because of the
distances involved, the number of available lanes is reduced, and it now requires 20 hr
to moveinto the 100- to 500-r zone and 25 to 30 hr to move to fallout-free areas — hours
many times in excess of the warning periods anticipated.
(b) Limited movement of the type planned in the Washington area (3-hr massradial
evacuation) could result in 100 percent lethality in the evacuated population.
(c) If civil defense planners are willing to accept a 70 percent level of risk, movement
in an eastward direction (20 to 120 deg) is still precluded by high indirect radiation conditions, but shorter movements to the west and south of 15 and 30 miles, respectively, may
be indicated. From 8 to 12 hr would be required to carry out this tactic — timesstill in
excess of expected warning times.
(d) If civil defense planners are willing to take a 50-50 chance (one-half the time the
radiation level will exceed that shown for a given area in Fig. 38, one-half the timeit will
be less), the situation is not appreciatively changed from the 70 percent confidencesitua-
tion. An appreciable sector east of Washington receives 500 to 1000 r; 15 to 20 miles of
movement west and south, and to a limited degree toward the northwest, is necessary.
The times required would still exceed expected warning times by a factor of 6 or 8.
50
ORO—R-17 (App B)