27 Normalization to external gamma-ray exposure rate of 1 mR/hr at 12 hr postshot The contours of the fallout pattern are drawn with the field readings corrected to a time 12 hr postshot (Di57). Therefore, all values, curies and mR/hr, are normalized to an exposure rate of 1 mR/hr at 12 hr postshot. The total exposure rate is given by T(t) = >, YR(A) 2,18), ; A | where T(t) = Total mR/hr as a function of time, assuming debris is uniformly spread over 1 km?, Normalized values are calculated by the equations that follow. Normalized mR/hr of each fission product: NMR (A) t where T(12) MR(A),/T(12), Total mR/hr at H + 12 hours assuming debris is uniformly spread over 1 km? (normalization factor). Normalized mR/hr of each neutron-induced nuclide: NIMR(A), = IMR(A),/T(12). Normalized mR/hr of total external gamma-ray exposure rate: NMR, = T(t)/T(12). Normalized fission product curies: NCI(A), = CI(A),/T(12).