Attachment 2-B SECRET CLEARANCE REQUIRED OACOFS, G-3, Q&T DIV Lt. Col. Young 52779 G3 385.2 (12 Sep 52) Positioning of Troops at Atomic Weapons Tests 15 DEC 52 DISCUSSION 1. On 5 June you directed that a study be made to determine the minimum safe distance from ground zero of an atomic explosion that troops can be located safely during a peacetime maneuver. A complete discussion of the study is contained in Tab A. 2. G4 and The Surgeon General have recommended that the exposure of personnel participating in peacetime field exercise in conjunction with atomic weapons tests, be limited to the following: a. Overpressure -- five (5) pounds per square inch. b. Nuclear radiation -- six (6) roentgens at any one test, of which no more than three (3) roentgens is prompt, whole body radiation. c. Thermal radiation -- one (1) calorie per square centimeter. 3. The Chief, Armed Forces Special Weapons Project (AFSWP) has furnished the technical weapons effects data based on the exposure criteria established in paragraph 2 above, necessary for determining the positioning of troops. 4. Safety factors have been applied to meet contingencies resulting from variations in yields and effects of weapons, and errors in delivery systems. RECOMMENDATION: 1. That you approve the exposure criteria set forth in paragraph 2 above with the further provision that no individual will receive more than six (6) roentgens in any six months period. 2. That the following criteria be approved as a basis for positioning troops at atomic tests. a. For tower shots MAXIMUM TROOPS TROOPS SELECTED IND PREDICTED FIELD IN OPEN IN TRENCHES IN TRENCHES 1 to 5 FT 4500 yds 3500 yds 2000 yds 5 to 10 6500 3500 2500 10 to 15 8000 3500 3000 15 to 20 9000 3500 3200 20 to 25 10,000 3500 3500 25 to 30 11,000 3700 3700 30 to 35 12,000 3800E 3800 35 to 40 12,500 4000 4000 G3 385.2 (12 Sep 52), Summary Sheet for CofSA, Positioning of Troops at Atomic Weapons Tests, 15 Dec 52 b. For 280 gun delivered missiles -- add 1000 yards to distances given in paragraph 2a above. c. For aircraft delivered bombs. (1) Add 3000 yards to distances given in paragraph 2a above. (2) Permit no selected individual closer than 6500 yards. d. Troop positions must be located so that a gun or aircraft delivered weapon is delivered along a line in front of and parallel to the troop position. COORDINATION G4 -- Concur -- Col. Kane, extension 54552 AFSWP -- Concur -- Gen Loper, extension 56375 OCAFF -- Concur -- (See Incl 4 to Tab A) 1 Incl C.D. EDDLEMAN Tab A, Complete Discussion w/incl Major General, GS Assist Chief of Staff, G-3 As amended by Memo from CR&D for C/S 3 FEB 53, subject as above (copy attached) (See memo from S to S to G-3, dated 4 FEB 53, subject as above) SECRET RESTRICTED DATA SECURITY INFORMATION ATOMIC ENERGY ACT -- 1946 COMPLETE DISCUSSION 1. On 5 June 1952 the Chief of Staff directed that a study be made to determine the minimum safe distance from ground zero of an atomic explosion that troops can safely be located during a peacetime maneuver. The study was requested because of the possible impact of an atomic explosion and its attendant psychological affect on troops for whom close atomic weapon support is provided. The directive for this stated that the use of highly trained and carefully indoctrinated volunteers should be considered. 2. a. At the request of G3, G4 recommended the following maximum overpressure and maximum dosages of nuclear and thermal radiation to which Army personnel should be exposed in peacetime maneuvers. (1) Overpressure -- 5 psi. (2) Nuclear radiation -- At any one test, a total of six roentgens, of which not more than three roentgens are prompt, whole body radiation. (3) Thermal radiation -- 1 calorie per square cm. b. The drag resulting from a five (5) psi overpressure is expected to create velocities which will project missiles of stones or debris which might injure personnel in the open, but probably not those in trenches. An individual standing against five (5) psi overpressure is expected to be thrown to the ground or against an obstacle with considerable force. It is not anticipated that troops in trenches will be injured by being thrown against the trench wall. The overpressure in trenches is expected to be twenty (20) per cont greater than in the open at the same range due to pressure build-up resulting from reinforcing reflections. c. There is no known tolerance for nuclear radiation, that is, there is no definite proof that even small doses of nuclear radiations may not, in some way, be harmful to the human body. On the other hand, there is no evidence to indicate that, within certain limits, nuclear radiation has injured personnel who have been exposed to it. Accordingly, permissible radiation dosages have been established on the basis of knowledge and experience accumulated to date. The Atomic Energy Commission (AEC) has established an average permissible dosage of 3 per week, not to exceed a total of 3r at any one test, for AEC personnel. This permissible dosage has also been prescribed for Army personnel at previous atomic tests. There is no evidence, however, that a total permissible dosage of 6r at one test will produce bodily injury and it is considered to be a completely safe limit. It is noted that it requires on the order of 100r to produce symptoms of radiation sickness, and the 50 per cent lethal dose is approximately 450 r. (1) The factors to be considered in establishing a peacetime permissible radiation dosage are not the same for the Army as for the AEC. The AEC is concerned with individuals who are permanent employees and who will be subject to exposure year after year in performance of their work. The Army is concerned with individuals who, during peacetime training, will be exposed to radiation very infrequently. In order to enable the Army to obtain maximum benefit from the troop participation at continental atomic tests, it is necessary that the permissible radiation dosage be high enough to permit soldiers to perform limited maneuvers and observe equipment displays in contaminated areas. In this regard, the exercise director at Exercise DESERT ROCK IV has recommended that the permissible dosage be increased above 3r for future exercises at the Nevada Proving Ground. (2) It is emphasized that the establishment of 6r as the Army's permissible dosage will not mean that every troop participant will receive that dosage. It is intended that troops will receive only that amount of radiation which is necessary to make the indoctrination realistic and effective. d. One (1) calorie per square centimeter will produce no physical effect. It will require approximately 2.5 calories per square centimeter to produce a burn comparable to a moderate sunburn. Three (3) calories per square container are required to produce blisters. 3. The limiting criteria established above were forwarded to the Armed Force Special Weapons Project (AFSWP) with a request that AFSWP determine, on the basis of this criteria, the minimum distance from ground zero troops may be positioned, assuming in each case a height of burst of the bomb that would maximize the effect under consideration. It was requested that the information be furnished in the form of a curve showing yield plotted against distance and that the date be accompanied by recommended safety factors. 4. AFSWP has submitted the requested information as shown in Inclosure 1. In summary AFSWP reports as follows: a. Assumptions (1) For heights of burst of 500 feet and below, the winds near ground level are in a direction to prevent drift of fall out in the direction of troops. SECRET RESTRICTED DATA SECURITY INFORMATION ATOMIC ENERGY ACT -- 1946 (2) Trenches used by troops are 6 feet deep and 2 feet wide and no part of troops in trenches project above a point 2 feet below surface. (3) The peak overpressure in trenches is 20 per cent greater than in the open at the same distance due to reinforcing reflections (4) Nuclear radiation received by personnel in trenches is 10 per cent of that received in the open at the same distance. (5) Personnel in trenches receive no direct thermal radiation and the reflected thermal radiation is 5 per cent of that which would be received in the open at the same distance. b. Limiting criteria. (1) Troops in trenches. (a) G-10 KT: Limiting factor is nuclear radiation (3 roentgens). (b) 10 KT and above: Limiting factor is overpressure (5 psi). (2) Troops in open. (a) g-1.5 KT: Limiting factor is nuclear radiation (3 roentgens). (b) 1.5 KT and above: Limiting factor is thermal radiation (1 cal/sq cm). (3) Regardless of yield , or positioning of troops in trenches or in the open, the hazard of neutron exposure limits the troops to positions no closer than 2000 yards from ground zero. c. Recommended safety factors. (1) Add 20 per cent to the maximum predicted yield to account for errors in yield computation. (2) In addition increase the distance computed for 120 per cent maximum yield as follows to account for possible errors in effects data. (a) For pressure effects and 20 per cent. (b) For nuclear radiation add 5 per cent. (c) For thermal radiation add 8 per cent. (3) Add 2000 feet when the nuclear device is dropped from an aircraft. RESTRICTED DATA -- ATOMIC ENERGY ACT -- 1946 d. Minimum safe distance for troops. (1) On the basis of information submitted by AFSWP the safe distances for positioning troops has been computed and tabulated in Enclosure 2. These distances including the recommended safety factors are: Yield Troops In Troops In KT Trenches Open 1 2000 yds 2130 yds 5 2010 4405 10 2545 6295 15 2905 7755 20 3190 8920 25 3445 9940 30 3650 10,800 35 3820 11,630 40 3995 12,420 (2) It is noted that for yield of 5 KT and below troops may be positioned at approximately 2000 yards and for yields of 20 KT and below troops can be positioned at approximately 3000 yards. These distances provide adequate safety factors to insure against the prompt effects of the weapon, but do not fully consider the danger that may result from a sudden wind shift which would scatter the radioactive fall out over the troop positions. Although weather data can be predicted with remarkable accuracy on occasion, it is unsound to have troop safety in a peacetime maneuver dependent upon a weather prediction. It is appropriate that a safety factor be introduced to account for this hazard. A recommended safety factor is to permit positioning of large bodies of troops no nearer than 3500 yards (2 miles) from ground zero. Assuming a maximum ground wind velocity of 10 miles per hour or less, this would allow a minimum of 12 minutes for the evacuation of the positions to get under 0way. It is doubtful that an atomic test wold be conducted if the ground wind velocity exceeded 10 miles per hour by an appreciable amount. (3) On the other hand it is feasible to station a group of selected individuals at the minimum distance permitted by the calculations shown in Enclosure 2. A small group is easily controlled and could be ordered out of the area within seconds after a wind shift was detected. 5. One other factor must be considered. When an atomic device is not detonated on a tower, but rather is delivered to ground zero by gun, guided missile, rocket, or aircraft it is necessary to consider the possibility of an error in the delivery system. a. The 280 cm gun is expected to deliver an atomic shell to the target at maximum range with a deflection error of less than 100 feet. However, there is always the possibility of an erratic round and the possibility of human error, notwithstanding the use of spotting rounds to zero in. Furthermore, an accident involving an atomic explosion, unlike an accident involving conventional weapons, would affect hundreds of individuals and would be more difficult to justify under any peacetime circumstances. Therefore, an added safety factor of 1000 yards is recommended when a 280cm gun is used to deliver the atomic explosive. It is further recommended that it be mandatory to have the troop positions parallel to the line of flight of the projectile in order to preclude overhead ire. b. The accuracy of guided missiles and rockets is not sufficiently established to be considered at this time. c. The accuracy of free falling serial bombs is controversial. The Air Force was asked to comment on this problem (Enclosure 3) but did not find it possible to recommend a safety factor. The Air Force did point out that to date their bombing operations at the Nevada Proving Grounds have not been in error more than 400 feet, but at the same time noted the possibility of greater error. The Aircraft to delivery system has inherent characteristics that subject it to error from many sources including the bombsight, weather, erratic ballistics of the bomb, and the human element in the bombardier. Office, Chief of Army Field Forces recommended that the safety factor to be applied in the case of aerial delivered weapons be reduced to 2000 yards (Enclosure 4). However, it is believed that due to the inherent inaccuracies in this delivery method, an arbitrary factor of safety of 3000 yards is proper when atomic weapons are so delivered. It is further recommended that it be mandatory to have troop positions parallel to the line of flight of the aircraft. 6. At the request of ILLEGIBLE, the Chief, AFSWP has requested AEC concurrence in the following proposals: a. The Department of Defense will be responsible for the radiological safety of all Service troops and troop observers participating in continental atomic weapons tests, and will establish the permissible radiation dosage for such personnel. b. The Department of Defense will determine, within an assigned sector, the distance from ground zero that troops and troop observers will be stationed at continental atomic weapons tests. 7. Pending the concurrence of the AEC in the above, it is recommended that the following criteria be adopted for exposure of Army personnel to atomic weapons effects and for positioning Army troops and troop observers at continental atomic weapons tests. a. Criteria for exposure to atomic weapons effects. (1) Overpressure -- five (5) psi (2) Nuclear radiation -- six (6) roentgens at any one test, of which no more than three (3) roentgens is prompt, whole body radiation. Furthermore, maximum of six (6) roentgens in any six months period. (3) Thermal radiations -- one (1) caloric/sq cm. b. Troop positions for tower shots. Max Predicted Troops In Troops In Select Ind Yield Open Trenches In Trenches 1 to 5 FT 4500 yds 3500 yds 2000 yds 5 to 10 6500 3500 2500 10 to 15 8000 3500 3000 15 to 20 9000 3500 3200 20 to 25 10,000 3500 3500 25 to 30 11,000 3500 3700 30 to 35 12,000 3800 3800 35 to 40 12,000 4000 4000 c. Troop positions for 200cm gun delivered missiles - -add 1000 yards to distances given in paragraph 7b. d. Troop positions for Aircraft delivered bombs. (1) Add 3000 yards to distances given in paragraph 7b (2) Permit no selected individuals closer than 6000 yards e. Troop positions must be located so that gun or Aircraft delivered weapon is delivered along a line in front of and parallel to the troop position. 4 Enclosures: 1. AFSWP Study 2. Troop Location Chart 3. AF Comment 4. OCAFF Comments LOCATION OF PARTICIPATING TROOPS AT CONTINENTAL ATOMIC TESTS TROOPS IN OPEN MAX PREDICTED PREDICTED YIELD MIN DISTANCE FROM YIELD (1) SAFETY FACTOR (2) OZ BASED ON 120% (Plus 20%) MAX YIELD for 3R for 4 cal/Sq Cm 1 KT 1.2 KT 2030 yds 1820 yds 5 6 2530 4080 10 12 NA 5825 15 18 NA 7180 20 24 NA 8260 25 30 NA 9200 30 36 NA 10,000 35 42 NA 10,770 40 48 NA 11,550 SAFETY FACTOR FOR MIN SAFE DISTANCE RECOMMENDED EFFECTS DATA Radiation FROM OZ POSITION OF TROOP (5%) Heat (8%) IN ILLEGIBLE FROM OZ All Troops Sal. Ind 100 yds 145 yds 2130 yds 3500 yds 2500 yds 125 325 4405 4500 4500 NA 470 6295 6500 6500 NA 575 7755 8000 8000 NA 660 8920 9000 9000 NA 740 9940 10,000 10,000 NA 800 10,800 11,000 11,000 NA 860 11,630 12,000 12,000 NA 920 12,420 12,500 12,500 NOTES: 1. Maximum predicted yield is the upper limit of yield predicted by the AEC. 2. Safety factors are as follows: Maximum predicted yield is increased 20%, and in addition the safe distance calculated there from is increased to account for possible errors in effects data. The safe distance for pressure calculation is increased by 20%, for radiation by 5%, and heat by 8%. 3. All shots assumed to be detonated on a tower, i.e., no error in location of ground zero. 4. Except for very low yields, thermal radiation is the criteria which limits location of troops in open. Nuclear radiation is the limiting factor up to 1.5 KT. 1 LOCATION OF PARTICIPATING TROOPS AT CONTINENTAL ATOMIC TESTS TROOPS IN OPEN MAX PREDICTED PREDICTED YIELD MIN DISTANCE FROM YIELD (1) SAFETY FACTOR (2) OZ (7) BASED ON (Plus 20%) 120% MAX YIELD For 5 PSI(5) For 3R(6) 1 KT 1.2 KT 950 yds 1820 yds 5 6 1675 1860 10 12 2120 2060 15 18 2420 2200 20 24 2660 2290 25 30 2870 2360 30 36 3040 2420 35 42 3190 2450 40 48 3330 2480 SAFETY FACTOR FOR MIN SAFE DISTANCE RECOMMENDED EFFECTS DATA (2) FROM GZ POSITIONING OF TROOPS Pressure Radiation IN YARDS FROM GROUND (20%) (5%) ZERO All Troops Selected Ind 190 70 1450 yds 3500 2000(8) 335 95 2010 3500 2000 425 105 2545 3500 2500 485 110 2905 3500 3000 530 115 3190 3500 3500 575 120 3445 3500 3500 610 120 3650 4000 4000 630 125 3820 4000 4000 665 125 3995 4000 4000 NOTES: 1. Maximum predicted yield is the upper limit of yield predicted by the AEC. 2. Safety factors are as follows: Maximum predicted yield is increased 20%, and in addition the safe distance calculated there from is increased to account for possible errors in effects data. The safe distance for pressure calculation is increased by 20%, for radiation by 5%, and heat by 8%. 3. All shots assumed to be detonated on a tower, i.e., no error in location of ground zero. 4. Calculations based on trenches 6 feet deep and 2 feet wide. 5. Pressure in 6 foot deep trench is assumed to be 20% greater than pressure in open distance. 6. Whole body radiation expected for troops in 6 feet deep 2 feet wide trench wherein no part of individual's body is closer than 2 feet from surface. Troops in open would receive approximately 30R at same distance. 7. Assume troops in trenches are shielded from direct thermal radiation and that reflected thermal radiation in the trench is not more than 5% of that which would be received in open at same distance. This assumption eliminated thermal radiation as a criteria at any range for troops in trenches. 8. The danger of neutron exposure limits positioning of troops no closer than 2000 yards. 2 RESTRICTED -- SECURITY INFORMATION Troop Participation at Continental Atomic Weapon Tests G3 G-3 354.2 (21 Aug 52)10 September 52 COFS, USAFLt. Col. Young/55260/ILLEGIBLE 1. The Department of the Army is currently investigating the safety factors which must be considered in positioning troops and troop observers at continental atomic tests. For the tests at which the atomic device is dropped from an aircraft, it is necessary to consider the possibility that the device may be dropped closer to troop positions than was intended. 2. It is therefore requested that this office be provided with the following information in connection with your operations at the Nevada Proving Ground. a. What is the probability that an atomic device will be dropped 500, 1000, 2000, and 3000 yards closer to the troops than planned, assuming: (1) The aircraft flies parallel to the troop positions. (2) The aircraft flies perpendicular to the troop positions, i.e., passes over them on the final bomb run. b. What factors of safety, in terms of distance, does your office recommend be used at atomic weapons tests to effect the danger which may result bombing errors? C.D. EDDLEMAN, Maj. Gen. GS Assistant Chief of Staff, G-3 FILE NO. 354.2 SUBJECT: (Unclassified) Troop Participation at Continental Atomic Weapons Tests TO: C8USA G3 FROM: Department of the Air Force Hq USAF - ATCAG 7 Oct 52 Content No. 2 Lt. Col. Cole/js/71666 AFOOP-OC-8 1. Your attention is invited to the following publications which provide bombing accuracies for each of the test drops at the Nevada Proving Grounds a. AFSWP publication, "Operation Roaster" b. AFSWP publication, (Operation Tumbler" preliminary report, Parts I & II, 15 May 1952. c. Los Alamos Scientific laboratory, University of California publication, "Operation Ranger", Vol II. 2. It will be noted that in no instance did range or deflection errors exceed four hundred (400) feet. If similar sighting methods and techniques are used in the future test, comparable accuracies should be obtained. 3. It will also be noted that the techniques of operations of the bombsight permit greater control of deflection errors than range errors. In view of these inherent characteristics of the bombsight, safety factors required will be decreased by the aircraft flying parallel to troop positions. 4. In consideration of possible gross errors in any operation dependent upon the Human element, it is apparent that no incontrovertible factors may be provided. However, the above bombing accuracy is considered representative of bombing methods which are likely to be used in future tests involving troop participation. FOR THE CHIEF OF STAFF: JOHN K. GERHART Brigadier General, USAF Deputy Director of Operations Deputy Chief of Staff, Operations