Introduction to Nuclear Weapons Physical Science

I. Nuclear Physics A. Key Concepts 1. The atom: Nucleus surrounded by electrons (a.k.a. beta particles)

2. The Nucleus: Protons and Neutrons a. Electro-magnetism holds electrons in orbit (electrons are negatively charges, protons are positive) b. “Strong nuclear force” holds protons and neutrons together (137 times as strong as electro- magnetism)

3. Elements a. Definition: Elements are atoms with the same # of protons in nuclei (their atomic number) b. Change # protons = change element c. Atomic weight = protons + neutrons + electrons (trivial weight) d. Change # neutrons but not protons = same element but different atomic weight  isotope (Carbon-12, Carbon-13, Carbon 14, etc.)

4. The novelty of nuclear weapons a. Chemistry – Elements are combined into compounds (atoms become molecules), which can release electro-magnetic energy as heat, light, etc. ALL weapons before 1945 use chemistry – explosives, napalm, toxins, etc. b. Nuclear weapons use the strong nuclear force for destruction  inherently more powerful than any possible chemical reaction (by weight)

B. Fission: Splitting a Nucleus 1. Heavy nuclei are unstable – Put too many protons together and they repel each other. Too many (or too few) neutrons can increase this repulsion. 2. Spontaneous fission: Unstable heavy nuclei can randomly fission – break into two smaller nuclei (different elements).

3. Induced fission Throw a neutron at an unstable nucleus and: Throw a neutron at an unstable nucleus and: It might escape (pass by without being captured by nucleus) It might escape (pass by without being captured by nucleus) Be absorbed into the nucleus Be absorbed into the nucleus Trigger fission of the nucleus into two nuclei (shown) Trigger fission of the nucleus into two nuclei (shown)

4. The Fission Chain Reaction a. More energy is required to hold one heavy nucleus together than two moderate-sized nuclei. b. Therefore, splitting a heavy nucleus releases a great deal of energy (strong nuclear force). c. If neutrons cause fission, and fission creates more neutrons, a chain reaction may ensue. Small initial energy (a few neutrons) cascades to trillions of split nuclei. d. Uncontrolled chain reaction = fission explosion. Requires Critical Mass (enough nuclei close together for neutrons to be more likely to hit nuclei than fly out of the mass without hitting anything) Uncontrolled chain reaction Uncontrolled chain reaction e. Critical mass varies by element, isotope, shape (spheres work best), and density (so compressing sub-critical mass can make it “go critical” and explode)

Example: Chain Reaction in U-235 Chain Reaction in U-235Chain Reaction in U-235

C. Fusion: Combining Nuclei Combining NucleiCombining Nuclei 1. It takes more energy to hold two light nuclei together than a single moderate- sized nucleus. 2. Therefore, forcing two light nuclei together into one nucleus generates energy. 3. In general, fusion produces more energy than fission (which means bigger bombs)

Curve of Binding Energy: Note energy increase in fusion (light elements) compared to fission (heavy elements)

4. The problem of fusion a. Fission is easy – just throw some neutrons at inherently-unstable nuclei and they split b. Fusion is hard – Hydrogen doesn’t just randomly slam into itself with the energy level of the sun’s core. About 100 million degrees required to overcome strong nuclear force. c. All efforts to create controlled fusion use more energy to force the nuclei together than they extract from fusion d. BUT we do have one tool to generate huge amounts of uncontrolled energy – a fission chain reaction! (Even this just barely provides enough energy – limiting fusion weapons to very light elements like hydrogen)

II. Weapon Design A. The most basic fission weapon (aka atomic bomb) – The U-235 weapon 1. U-235 is fissile – Only low-energy neutrons are needed to split the nucleus. Other types of uranium (U-238, the most common type) require very high-energy neutrons for fission (= nearly impossible to create a chain reaction) 2. Critical mass of U-235 = 50 kg (about 110 pounds) in a sphere.

Advantage of U-235 over U-238

3. The gun-type nuclear weapon a. Principle = Quickly mash two sub-critical pieces of U-235 together into one piece above critical mass. Detonation ensues. b. Simplified design:

4. Barriers to building a gun-type weapon a. Getting the U % of Uranium is U-238. Must enrich uranium to increase % of U % of Uranium is U-238. Must enrich uranium to increase % of U-235 Combine uranium with fluorine to make uranium hexafluoride gas (“hex”). Then put hex in a container surrounded by a membrane. Slightly more U- 235 will diffuse out than U-238. Also useful… Combine uranium with fluorine to make uranium hexafluoride gas (“hex”). Then put hex in a container surrounded by a membrane. Slightly more U- 235 will diffuse out than U-238. Also useful…

Gas Centrifuges Since U-235 is lighter than U-238, spinning hex rapidly pulls the U- 238 to the edge and leaves more U-235 in the middle Since U-235 is lighter than U-238, spinning hex rapidly pulls the U- 238 to the edge and leaves more U-235 in the middle US cascade of centrifuges  US cascade of centrifuges 

b. The danger of “fizzle” Difficult to eliminate the last U-238 from the U-235 (Hiroshima bomb was 80% U-235 / 20% U-238) Difficult to eliminate the last U-238 from the U-235 (Hiroshima bomb was 80% U-235 / 20% U-238) U-238 spontaneously fissions, generating neutrons U-238 spontaneously fissions, generating neutrons Danger = chance that U-238 will start a partial chain reaction just before critical mass is reached. Blows U-235 apart before most of it has a chance to fission. Result = small explosion. Danger = chance that U-238 will start a partial chain reaction just before critical mass is reached. Blows U-235 apart before most of it has a chance to fission. Result = small explosion. Solution = assemble critical mass so quickly that U-238 is unlikely to spontaneously fission at the wrong moment (we now know Hiroshima bomb had just under a 10% chance of fizzle – the U-238 in the weapon spontaneously fissioned about 70 times/second) Solution = assemble critical mass so quickly that U-238 is unlikely to spontaneously fission at the wrong moment (we now know Hiroshima bomb had just under a 10% chance of fizzle – the U-238 in the weapon spontaneously fissioned about 70 times/second) Similar problem makes U-233 gun-type bombs difficult to build (contaminated with U-232, which fissions too rapidly) and Pu- 239 ones impossible (contaminated with Pu-240) Similar problem makes U-233 gun-type bombs difficult to build (contaminated with U-232, which fissions too rapidly) and Pu- 239 ones impossible (contaminated with Pu-240) More complex designs reduce – but do not eliminate – chance of fizzle. DPRK test probably fizzled (very small blast) More complex designs reduce – but do not eliminate – chance of fizzle. DPRK test probably fizzled (very small blast)

c. Safety problems i. Accident-prone: Two subcritical masses kept in close proximity to explosives ii. Accidental moderation: Seawater moderates (slows) neutrons, and slower neutrons are more likely to cause fission before escaping the core. Result = drop bomb in seawater = potential detonation! iii. Terrorist’s dream: Easy to use U-235 to improvise a nuclear device

B. The Basic Implosion-Type Fission Weapon 1. Why bother? a. Desire to use Pu-239 (can be made using nuclear reactors, so no separation necessary) b. Compressing material takes 1/10 the time of slamming it together (helps prevent fizzle) c. Less fissile material is required if it can be compressed d. Much safer – accidental detonation can be made impossible e. Allows flexibility: some or all charges can be detonated, compressing material to different degrees

Advantage of Pu-239 

2. The basic components a. Subcritical mass of Plutonium (any isotope), U- 233 (rarely), U-235, Np-237 (similar to U-235 but easier to obtain), or Am-241 (theoretically) surrounded by explosives  nearly all designs use Pu-239 or U-235 b. Explosives are shaped, layered, and timed to generate a spherical shock wave c. Neutron initiator supplies neutrons to begin fission at right moment – too soon causes fizzle, but so does too late (material rebounds after compression) d. Tamper between explosives and Pu-239 helps to reflect neutrons and hold compression for a moment or two to maximize yield

Simplified Implosion Design

3. Maximizing Efficiency (Proportion of material that fissions before the whole thing blows itself apart into sub-critical pieces) a. Neutron reflector: Surrounds fissile material below tamper to bounce stray neutrons back into the core b. Levitating core: Empty space between tamper and core to allow tamper to build up momentum (standard in today’s weapons) c. External neutron trigger (particle accelerator outside the sphere) – also useful if you want to put something else in the center of the core….

C. Boosted Fission Weapons: Using Fusion to Increase Power 1. Problem: Most fissile material wasted (only 1%-20% fission before it blows itself apart – Hiroshima bomb was 1.4% efficient). More neutrons needed! 2. Solution = fill core with isotopes of H that fuse easily: Deuterium (D or H proton, 1 neutron) and Tritium (T or H proton, 2 neutrons) can fuse into He-4 (2 protons, 2 neutrons), creating energy and 1 extra neutron. Fusion energy generated is trivial in these weapons, but… The “boost”: Extra neutrons hit the fissile material and cause more of it to fission before blowing itself apart. Result = much larger explosion (about double the explosive power) Advantages: Higher yield for equal mass – which also means weapons can be miniaturized (up to a point), “dial-a-yield” through control of D/T injected into center.

Schematic of Primary Part of Boosted Fission Weapon Aluminum case (1 cm) High explosive (10 cm) Tamper (tungsten or uranium) (3 cm) Beryllium reflector (2 cm) Fissile material (U-235 or Pu-239) Hollow core, where D (H-2) and T (H-3) are injected for boosting.

C. Boosted Fission Weapons: Using Fusion to Increase Power 1. Problem: Most fissile material wasted (only 1%-20% fission before it blows itself apart – Hiroshima bomb was 1.4% efficient). More neutrons needed! 2. Solution = fill core with isotopes of H that fuse easily: Deuterium (D or H proton, 1 neutron) and Tritium (T or H proton, 2 neutrons) can fuse into He-4 (2 protons, 2 neutrons), creating energy and 1 extra neutron. Fusion energy generated is trivial in these weapons, but… 3. The “boost”: Extra neutrons hit the fissile material and cause more of it to fission before blowing itself apart. Result = much larger explosion (about double the explosive power). 4. Advantages: Higher yield for equal mass – which also means weapons can be miniaturized (up to a point), “dial-a-yield” through control of D/T injected into center.

D. Staged Fusion Weapons: The Thermonuclear or Hydrogen Bomb 1. Parts: a. The “primary stage” – A fission device b. The “secondary stage” – designed to fuse when bombarded with radiation c. The casing: Usually made of U-238

2. Inside the Secondary Radiation channels filled with polystyrene foam surround the capsule Radiation channels filled with polystyrene foam surround the capsule The capsule walls are made of U-238 The capsule walls are made of U-238 Spark plug of plutonium boosts fusion Spark plug of plutonium boosts fusion

3. Radiation Implosion a. Primary ignites  high-energy X-Rays b. X-Rays fill the radiation channels, turn polystyrene to plasma c. Tamper is heated  outside ablates (vaporizes – think of an inside-out rocket). Ablation compresses the nuclear fuel. d. Plasma helps keep the tamper from blocking the radiation channels, increasing duration of compression

4. The fusion explosion a. Compressed fuel must still be heated b. Plutonium “spark plug” in center of fusion fuel is compressed, becomes super- critical and fissions (raises temperature inside case) c. Result = huge pressures and temperatures produce fusion, which releases far more energy than fission PLUS “fast fission” of spark plug from fusion-produced neutrons

5. The fuel a. Early designs (first US test) used deuterium and tritium – but this required cryogenic machinery (D and T are gases at room temperature) b. Modern designs use solid Lithium Deuteride instead. Enriched fuel (lots of Li-6) much more effective. c. The fusion process: Neutrons from fission turn some D into T, which then fuse together, generating more neutrons. Some D and T also fuses with Lithium (but this generates less energy).

E. Enhanced Fusion Weapons 1. Fission-Fusion-Fission designs: Make the bomb case out of U-238 or even U-235 and it will detonate when neutrons from the fusion capsule hit it, greatly enhancing yield (doubling power is easy) 2. Multi-stage weapons: Use the secondary stage to compress a tertiary stage, and so forth. Each stage can be times larger than previous stage (= unlimited explosive potential)

III. Detonation Parameters A. Yield – A measure of explosive power 1. Expressed as kt or Mt of TNT 2. Measures power not weight – 20 kt weapon is equivalent to detonating 20,000 TONS of TNT all at once. 1 Mt means the equivalent of a million tons of TNT detonating at once.

Examples: “Tiny” to Huge Oklahoma City non-nuclear bomb (.002 Kt) Oklahoma City non-nuclear bomb (.002 Kt) Davy Crockett nuclear rifle (.01 kt) Davy Crockett nuclear rifle (.01 kt) Davy Crockett Davy Crockett British tactical nuclear weapon (1.5 kt) British tactical nuclear weapon (1.5 kt)tactical nuclear weapontactical nuclear weapon The nuclear cannon (15 kt) The nuclear cannon (15 kt)nuclear cannonnuclear cannon Hiroshima (15 kt) and Nagasaki (20 kt) Hiroshima (15 kt) and Nagasaki (20 kt) Hiroshima Max pure fission: Orange Herald (720 kt) Max pure fission: Orange Herald (720 kt)Orange HeraldOrange Herald Chinese (3 Mt) and British (1.8 Mt) H-Bombs Chinese (3 Mt) and British (1.8 Mt) H-Bombs ChineseBritish ChineseBritish Largest deployed weapon (25 Mt) Largest deployed weapon (25 Mt) Tsar Bomba, the largest bomb tested (58 Mt) Tsar Bomba, the largest bomb tested (58 Mt) Tsar Bomba Tsar Bomba

Comparative fireballs by yield

B. Height: Air-Burst vs. Ground-Burst Zones of destruction (1 Mt weapon) Groundburst (energy concentrated at ground zero): Airburst (energy distributed over wider area):

IV. Effects of Nuclear Weapons A. Prompt effects 1. Thermal and visible radiation (heat and light) a. Initial pulse = 1/10 second (too quick for eyes to react). Few killed, but many blinded b. Second pulse = most heat damage, lasts up to 20 seconds for large weapons

c. Biological effects i. “Flash burns” – Most prominent on exposed areas (i.e. dark areas of kimono worn by this victim)

Burns 1.5 miles from hypocenter in Nagasaki

Add 20% for 1 st degree burn range, subtract 20% for 3 rd degree burn range

ii. Blindness: Most far-reaching prompt effect Flash blindness (temporary) and retinal burns (permanent) from light focused on retina Flash blindness (temporary) and retinal burns (permanent) from light focused on retina

iii. Fire Storms Heat ignites flammable materials Heat ignites flammable materials If large enough area burns, it creates its own wind system, sucking in oxygen to feed the flames If large enough area burns, it creates its own wind system, sucking in oxygen to feed the flames Natural example in Peshtigo, WI (1871): “A wall of flame, a mile high, five miles (8 km) wide, traveling 90 to 100 miles (200 km) an hour, hotter than a crematorium, turning sand into glass.” Natural example in Peshtigo, WI (1871): “A wall of flame, a mile high, five miles (8 km) wide, traveling 90 to 100 miles (200 km) an hour, hotter than a crematorium, turning sand into glass.” Firestorms in Hiroshima (but not Nagasaki), Dresden, Tokyo in World War II. Firestorms in Hiroshima (but not Nagasaki), Dresden, Tokyo in World War II. Result: Large numbers of people not burned by nuclear detonation will be burned by subsequent firestorms sweeping through city Result: Large numbers of people not burned by nuclear detonation will be burned by subsequent firestorms sweeping through city

2. Blast damage a. Heat of fireball causes air to expand rapidly, generating a shock wave b. Shock wave hits and damages buildings, and is followed by… c. Low-pressure area follows and sucks everything backwards (blast wind)

Note the Mach Front:

1 Mt

d. Biological Effects Few likely to die from blast wave itself, but flying debris may kill many Few likely to die from blast wave itself, but flying debris may kill many Lung damage occurs at about 70 KPa (double the pressure needed to shatter concrete walls) Lung damage occurs at about 70 KPa (double the pressure needed to shatter concrete walls) Ear damage begins at 22 KPa (as brick walls shatter) Ear damage begins at 22 KPa (as brick walls shatter) In general, heat will kill anyone close enough to experience primary blast damage. Crushed buildings will kill many outside this zone. In general, heat will kill anyone close enough to experience primary blast damage. Crushed buildings will kill many outside this zone.

3. Ionizing Radiation For most weapons, immediate radiation (gamma rays and neutrons) will only kill those very close to the explosion For most weapons, immediate radiation (gamma rays and neutrons) will only kill those very close to the explosion More on biological effects later… More on biological effects later…

Hiroshima Health Dept Estimates

4. Electromagnetic Pulse (EMP) High-altitude nuclear bursts generate magnetic fields over large areas (induces current in transistors and integrated circuits)  fried electronics High-altitude nuclear bursts generate magnetic fields over large areas (induces current in transistors and integrated circuits)  fried electronics

B. Fallout 1. Definition: Radioactive particles fall to earth (fission products, contaminated soil and debris sucked up by explosion) sucked up by explosionsucked up by explosion

2. Dangers of Ionizing Radiation a. Alpha radiation i. Composed of Helium nuclei (2 protons, 2 neutrons) ii. Little danger unless inhaled or ingested – stopped by a piece of paper (or skin) iii. Very destructive if inhaled or ingested (only known example = Alexander Litvinenko, poisoned with alpha-emitter Po-210)

b. Beta radiation i. Consists of electrons emitted by radioactive atoms ii. Can burn exposed skin – stopped by clothing, skin, and goggles iii. Effective range is only a few feet, so exposure to radioactive dust is most likely source of damage (no known fatalities from beta exposure at Hiroshima or Nagasaki)

c. Gamma radiation i. Extremely high energy photons emitted by the detonation and fallout ii. Penetrating power is high. Needed to reduce exposure by half:

d. Neutron radiation i. Produced by blast itself, insignificant in fallout ii. Induces radioactivity (alpha, beta, gamma) in materials it encounters iii. Shielding requires light elements (hydrogen, lithium) iv. Enhanced-Radiation Weapons, aka “Neutron Bombs” -- permit fusion-produced neutrons to escape, killing people even in armored vehicles (explosions still level civilian structures)

e. Measures of Radiation i. Measurements of exposure: 100 rad = 1 gray ii. Relative biological effectiveness (RBE): alpha = up to 20, neutron varies, beta/gamma/X-Rays = 1 iii. Measures of effect: rad * RBE = rem, gray * RBE = sievert iv. Since gamma exposure is likely to be source of most radiation poisoning, rad usually = rem and gray usually = sievert

f. Radiation Poisoning (Acute Radiation Syndrome) i. Triggered by cumulative exposure – hourly dose * hours exposed

ii. LD 50 is 4.5 Grays

g. Danger of Internal Absorption Strontium-90 is chemically similar to Calcium  incorporated into bones Strontium-90 is chemically similar to Calcium  incorporated into bones Iodine 131 is absorbed by the thyroid Iodine 131 is absorbed by the thyroid Cesium 137 is chemically similar to potassium and absorbed throughout the body Cesium 137 is chemically similar to potassium and absorbed throughout the body

3. Distribution of Fallout a. Fallout = “point-source pollutant” (exposure almost always decreases with distance) i. Key variables = speed and direction of wind. ii. Closer to source usually more dangerous – but downwind “hot spots” are possible

1 Mt Surface Burst: Cumulative and Hourly Radiation Exposure

“Hot Spots” from Castle Bravo Test

b. US-USSR Predictions Immediate Deaths: Immediate Deaths:

Fallout (1977 estimates):

Fallout (1990 Estimate)

Fallout (USSR Estimate)

4. Half-Life a. Definition: Time for 50% of a radioactive substance to decay b. Short half-life: These isotopes are very radioactive but don’t last long c. Long half-life: These are less radioactive but also long-lived

Example: 100 KT Surface Blast, Fort Hood Main Gate 100 KT = larger than ordinary fission bomb, smaller than largest Russian weapons 100 KT = larger than ordinary fission bomb, smaller than largest Russian weapons

15 psi: Virtually all dead 5 psi: 50% dead, 45% injured 2 psi: 5% dead, 45% injured) 1 psi: 25% injured

Compare: 1 MT Surface Blast

Compare: 20KT Surface Blast

100 KT Surface: Fallout 1 hour: Lethal2 hours: Lethal3 hours: Lethal4 hours: Lethal and 50% Lethal 5 hours: Lethal and 50% Lethal Possible Zone of Sickness

C. “Nuclear Winter” Nuclear WinterNuclear Winter 1. Theory that nuclear war would cause global cooling  bigger nuclear wars = more and longer cooling 2. Mechanism: Soot and smoke from urban firestorms and forest fires rises to stratosphere, carried around globe, remains for prolonged time, blocks sunlight

Nuclear Holocaust Cities burn Ground bursts Massive amounts of smoke Massive amounts of dust Sunlight absorbed Sunlight reflected Very little sunlight reaches the ground Rapid, large surface temperature drops “Nuclear Winter”

3. Technical Issues (See Pry) a. Initial TTAPS study (dramatized here) was poor dramatized heredramatized here b. Models assume carbon lofted into stratosphere – but this process is only confirmed for very small particles (diesel soot) c. Models assume urban/forest targeting – bases may be more logical targets d. Standard objections to climate modeling (no global climate models are perfect)

4. Political Issues: Why Hard-Liners (such as Pry) Opposed the Theory a. Theory undermines conventional deterrence: if nuclear winter is believed by policymakers, the world is safe for conventional war b. Theory undermines nuclear deterrence: Irrational to retaliate if doing so makes nuclear winter worse for everyone (including one’s own people) c. Theory undermines rationale for nuclear arms race: more weapons threaten human extinction if used (early studies come from left-wing scientists and environmentalists)

5. Scientific Analysis a. Cold War studies: Better science generally found smaller “nuclear winter” effects (note that most studies were excluded from Pry’s chart on p. 203 – which was taken from the conservative National Review)

b. Post-Cold War Studies Almost no studies : Why? Almost no studies : Why? 2006 study: 100 Hiroshima-sized bombs on 100 subtropical cities (obviously talking about India and Pakistan) 2006 study: 100 Hiroshima-sized bombs on 100 subtropical cities (obviously talking about India and Pakistan)

b. Post-Cold War Studies Almost no studies : Why? Almost no studies : Why? 2006 study: 100 Hiroshima-sized bombs on 100 subtropical cities (obviously talking about India and Pakistan) 2006 study: 100 Hiroshima-sized bombs on 100 subtropical cities (obviously talking about India and Pakistan) Predicts that some tropospheric soot (which usually rains out quickly) would be heated by the sun and enter the stratosphere (where no rain occurs) Predicts that some tropospheric soot (which usually rains out quickly) would be heated by the sun and enter the stratosphere (where no rain occurs) Predicts reduced cooling but lasts longer (up to 10 years) Predicts reduced cooling but lasts longer (up to 10 years)

Chief danger: Food Supply Summer won’t turn to winter – but it may turn to autumn, with repeated freezes threatening crops Summer won’t turn to winter – but it may turn to autumn, with repeated freezes threatening crops

Chief danger: Food Supply Summer won’t turn to winter – but it may turn to autumn, with repeated freezes threatening crops Summer won’t turn to winter – but it may turn to autumn, with repeated freezes threatening crops Besides temperature, ozone depletion, changes in precipitation, and reduced sunlight all reduce productivity Besides temperature, ozone depletion, changes in precipitation, and reduced sunlight all reduce productivity

2008 Study: A “SORT” War Imagines 2012 global nuclear war using arsenals which have been reduced by (existing) arms control agreements Imagines 2012 global nuclear war using arsenals which have been reduced by (existing) arms control agreements

“SORT war” scenario: open to question… “SORT war” scenario: open to question…

Comparison: Regional (5 Tg) vs. SORT (150 Tg or more)

D. Popular Perceptions and Propaganda 1. Examples of anti-nuclear research and culture: Nuclear Winter: Theory popularized by Carl Sagan before academic publication (PARADE Magazine) Nuclear Winter: Theory popularized by Carl Sagan before academic publication (PARADE Magazine) Film treatments dramatize dangers in 1980s: Film treatments dramatize dangers in 1980s: The Day After The Day After The Day After The Day After Threads Threads Threads When the Wind Blows When the Wind Blows When the Wind Blows When the Wind Blows

Soviet Propaganda: Examples “Two worlds - two goals. We are planning new life. They are planning death.” “Two worlds - two goals. We are planning new life. They are planning death.”

Soviet Propaganda: Examples “A Christmas present for the people” “A Christmas present for the people”

Soviet Propaganda: Examples “What dangerous madness!” “What dangerous madness!”

Soviet Propaganda: Examples “Myth – and reality.” “Myth – and reality.”

D. Popular Perceptions and Propaganda 1. Examples of anti-nuclear research and culture: Nuclear Winter: Theory popularized by Carl Sagan before academic publication (PARADE Magazine) Nuclear Winter: Theory popularized by Carl Sagan before academic publication (PARADE Magazine) Film treatments dramatize dangers in 1980s: Film treatments dramatize dangers in 1980s: The Day After The Day After The Day After The Day After Threads Threads Threads When the Wind Blows When the Wind Blows When the Wind Blows When the Wind Blows Soviet Propaganda Soviet Propaganda Responses: Responses: Indictments of the TTAPS study (long after others have moved on) Indictments of the TTAPS study (long after others have moved on) Pry, “Societal Survival” (Assigned) Pry, “Societal Survival” (Assigned) Most responses focused on elites, not public (no counter-films, for example). Why? Most responses focused on elites, not public (no counter-films, for example). Why?