Compilation of Nuclear Test Flash Blindness and Retinal Burn Data and Analytic Expressions for Calculating Safe Separation Distances
Final rept. Feb 1970-Apr 1971
URS RESEARCH CO SAN MATEO CA
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Characteristics of the human eye that affect the eyes sensitivity to thermal radiation, and potential protective measures are summarized. Nuclear bursts at which flash-blindness and retinal burn effects have been documented are identified, and the effects are reviewed and evaluated. Laboratory studies on flash-blindness are briefly reviewed, and wide variations are noted in individual recovery times from effects produced by the same source under the same conditions. Analytical equations derived from analysis of nuclear burst data are presented for calculating the following parameters of thermal radiation 1 fireball radius as a function of time 2 time to final thermal maximum, t sub f, for air burst 3 radiant exposure up to 10 t sub f 4 rate of thermal energy delivery as a function of time 5 fraction of thermal energy delivered as a function of time 6 rate of thermal energy delivery at time of first thermal maximum. Criteria based on nuclear test effects are evaluated for prevention of retinal burn. Separation distances, based on the criteria, and calculatated by use of the analytical equations are presented graphically for the following conditions safe viewing by unprotected dark-adapted subjects on the ground of only the first 100 msec of night bursts of yields of 1, 10, 45, 100, and 1000 kt at altitudes from 1 to 20 km safe viewing for night-adapted visually unprotected subjects coaltitude with the same burst yields. Results are estimated accurate within 25 to 50.