f Fallout Deposition The calculation of the shipboard (H+1) r/hr dose rate contour distances a- Jong the hot line was accomplished after the location of the fallout intercept had been determined. Table 2 shows the H+] hr (unit reference) dose rate values obtained from ref. 3 together with the calculated values of the H+1 dose rates extrapolated down range to the ship. for this extrapolation. Various functional forms were investigated A power law curve of the form yzax? provided the closest fit over the reference 3 distance and was used to obtain the extrapolated unit reference value of 12.2 r/hr for the ship at its intercept location. Making the conservative assumption that fallout with an 18 knot downwind’ speed could persist for roughly 10 hours at a specific geographic location (ref. 6), deposition on the deck of PATAPSCO (12 knots) moving relative to fallout cloud at only 6 knots might persist for 30 hours or 360 additional nautical miles ‘ wnwind. For the purposes of the conservative dose calculations presented here the maximum unit-reference dose rate of 12.2 r/hr at the initial intercept point will be used with the all-down time of 021520 or H + 32.5 hours. Table 2 Unit Reference (H+1) Dose Rate Contour Curve Fitting and Extrapolation Dose Rate Contour (y) 3000 2000 1000 500 100 50 35 | 12.2 10 7 Reference 3 Distance (x) 94.8 107.0 Calculated * Distance (x) 9) 105 127.0 ‘132 296.7 - 288 364 . 160.1 = - 167 Al} 586 | - 627 1365 * y =(1.92 x 10°)x 78-96 with coefficient of determination, r@ = .99 (6)