130001 PRIVACY ACT MAIERIAL _REMOVED - Prest' nt R Oppenheimer R Holman L H Hempelmann Col Warren Capt • I Nolan J Hoffman J Hirschfelder V• Weisskopf · l agee Capt T Jones and P C ' ' Abersold I Hirschfelde µL Cc discuss mechanism by which radioactive materials out or cloud - _ After explosion most of active material is on fringe of ball of fire 1to ·'- • k nve its gro expanded 100 rt i u of flre will When rt' · from ground be 10 · ·'' 'Refiected shoclf wave w i ll Jring up some dirt larg ely vapor zed hf eet lo ' f AJ · '''l tO T t o ·f ' ' · · energy of ·gadget il PDall of fire - 500 tons TNT at most vaporize 100-200 tons M UJ i l ' i · pt s nd - _Under ball of fire will be air under compression-after shock wave passed - · · ' ' dirt will pop up i Fig I 7' r t-l u' l r- · F · - n- -P -' '° ___ - -- -- L· jf t· i y l' Moat of dirt will go out at angles but there will be conditions of turbu- '-1-·o· lence bringing earth into ball of iz'e Vaporized sand will form smoke material wil be •posited on smoke •nd on s•nd Oppenheimer quostioned_deposition 'C'lf n sand as compared with formation of nuclei of active material t out Active Weisskopf pointed that there would be a competition for the active material by atoms smoke and - « - i sand Time for active atoms to find each other is longer than for active atoms to i- - find smoke and sand particles Guess that 10% to 50% of activity deposits on sand - - · Thia ball of fire cools in a f ow tenths to several seconds during which time · ·all activity condenses on smoke or sand Assumed rise to 12 000 feet Copied From Los Alamos ·National letbon itary ie corda CenterI Archlvea ttu -2- or Particle size and time Diam u 840 250 149 74 fall t fall ·hrs %Act 110 208 J 8 12 6 14 5 18 l 585 2 37 less than 74 51% If all activity on cold sand following table results Figure III Distance from zero n· JO JO JO 12 000 24 000 12 000 12 000 2 4 000 24 000 12 000 2 12 12 30 Dan5er ends after bout wind velocity 2t hrs JO J0-60 60 30 JO 60 10 R br on ground 4 6 3 15 reduced by lateral 11 spread 100 110 reduced by lateral sproad 200 0 6 PRIVACY ACIMAJf-RJAL BEMQVEfl -J- Low ground winds improve situation by not earring activity as far winds should help spread activity cloud up Ground Afternoon thermals very strong will break Cloud gets bigger as h increases - 1lateral spread greater as h increases • Summariz -vi ' ' t • • ' f ·11- l Prefer wind velocity not too high propose 15-30 mi hr 2 Inversion at any altitude above 8-10 000 ft will be O K J Wind not blowing over Carrizozo ·· - · i - ··_······· v t ••• lb· l 4 Exclude rain within morning hours 5 Unlikely •eeks o • e wo1 took 6or in two q o o f though a wind velocity of JO mi hr along either the N or S 11 blow I'' f and an inversion around 12 000 ft would be best Directions of wind were considerod - -· · low wind to get into trouble unless direction indeterminate tl · _ - in a South blow over Oscuro ' ' near towns and has two mountain ranges to E I ovide turbulence spreading 7 O vvu t Q 1 · 70-· 'r'-'-'- - 'if · - _ falling range 2i hrs dose will be small At end of North blow over Largo - or Coyote has lots or farms but not much population close • ·N _ _ __ ' - ' - ·CO · '' -' ' Question of integral dose ccnsidered After 6 hrs can get 4 times dose Ct- -_a eady accumulated • Effect of rain and wind ma7 reduce i N It ' ct __ W'r V l '1 · 'WQuld if peak reached lOr Would make measurements for several hours and cob sider evacua tion if total dose reached final total of 60-lOOr · · _ '·- - _ - - 4i J t Tolman thought height of inversion not important since if too low cloud ·will go through it low wind velocity would be desirable plans for evacuation · c r· ' should be very good · '· ''· 't Plans for evacu tion lust be effective Means a· definite direction should be picked V eather policy will be made will be made definite at Trinity-meeting Thursday By Saturday rehears l plans of t redical Group can be definite