Presentation on theme: "Nuclear weapons and their effects –Educating for a change. Alan Slavin, Department of Physics, Trent University, March 9, 2007."— Presentation transcript:
Nuclear weapons and their effects –Educating for a change. Alan Slavin, Department of Physics, Trent University, March 9, 2007
AGENDA 1.Militarism in a broader context 2.Nuclear weapons and their effects 3.Existing treaties 4.Changing US policy 5.What we can do KEEP IN MIND: Still some 26,000 nuclear weapons in the world today, BUT none has been used in war since 1945.
Militarism “Third-world” development Broader Context: Three closely related problem areas in the world today. Environment Cost of Militarism (Reference: UN Development Programme, 2001) The world spends more than $1 trillion /year on militarism = $2 million/minute or $200 per person /year.“ Reducing military expenditures of core countries (~$500 billion/yr) by less than 10% each year would pay the costs, for everyone in poorer countries, of Basic education Water and sanitation Basic health and nutrition Education/programs for birth control
About 80% of the world’s military expenditure goes conventional (non- nuclear) arms. Most exported arms are used against the inhabitants of the purchasing country. Canada was the world's 8th largest arms exporter in Pollution Poorer countries often destroy their environments, through deforestation, unregulated mining, etc, to pay for basic services such as health and education. Global warming is aggravated by the rapid development of poorer countries as they burn coal to provide electrical power. Emissions from military operations cause 6 to10% of global air pollution and contribute significantly to global warming. (World Watch Institute 2000).
The atom: -heavy nucleus contains protons and neutrons -surrounded by orbiting electrons p, n electron CONSTRUCTION OF NUCLEAR WEAPONS For example, Uranium-235 (or 235 U) has 235 neutrons and protons in its nucleus. That is, mass number A = 235.
1. Fission is the breaking up of a heavy nucleus to release energy ("fissure“) neutron (n) 235 U produces mimi mfmf radioactive fission fragments + n + n +ENERGY as heat, X-rays and gamma rays. + n E = m i c 2 – m f c Fusion is the melting together (fusing ) of 2 light nuclei to form a heavier one. Example: 2 H + 3 H 4 He + n + energy heat and pressure ENERGY CAN BE RELEASED FROM THE NUCLEUS IN TWO WAYS
FISSION CHAIN REACTION If only small amount of 235 U, most of the neutrons will escape without causing another fission process. If more than a "critical mass" of 235 U, a chain reaction will occur. 235 U n n n n n n n n n n n n + ENERGY n
Fission Bomb Simplest is “gun“ approach: 2 sub-critical 235 U masses shot together to form a critical mass (Hiroshima bomb). Most countries could make such a bomb if they had the U or Pu (32 do, in 2007). Critical mass: ~50 kg for 235 U, ~12 kg for plutonium-239 (about the size of a grapefruit). 239 Pu was used in the Nagaski bomb. Energy released from 12 kg of 239 Pu = 4000 tons of TNT (1000 tons = 1 kiloton = 1 kT). = electrical output of Pickering A power plant for 6 days at 2000 MW (1 MW = 1 megawatt = 1 million watts) The Hiroshima bomb was 12 to 15 kT.
Fusion bomb (or helium-bomb, or H-bomb) Bomb casing U or Pu 2 H & 3 H X- rays & Gamma rays Fission bomb trigger ignites fusion bomb fuel Chemical explosives Chemical explosives compress U or Pu → fission bomb. X- and gamma rays compress fusion fuel → fusion bomb. Fusion bombs up to 20 MT = 1000 x Hiroshima bomb. More typical: 0.2 to 1 MT (10 to 50 x Hiroshima). 1 MT = energy in coal train 300 km long.
First hydrogen-bomb test, Operation Ivy, at Enewetak atoll, 10.4 MT. The mushroom cloud climbed to 17 km in only 90 seconds, entering the stratosphere. One minute later it reached 33 km, eventually stabilizing at a ceiling of 37 km. Half an hour after the test the mushroom stretched 100 km across, with the base of the mushroom head joining the stem at 14 km.
EFFECTS OF A 1-MT BOMB EXPLODED AT 1.8 KM HEIGHT SHORT-TERM EFFECTS 1. Heat pulse 2. Blast 3. Radiation sickness 1. Heat pulse: - second degree burns at 13 km - 3rd degree burns at 10 km - ignition of clothing at 8 km If 2nd degree burns over 30% of the body or 3rd degree burns over 25% of the body, the burns are fatal if not treated promptly. In all the USA, there are facilities for a few thousand burn cases. A single bomb could cause 10, Blast The intense heat of the explosion causes a pressure pulse that extends out in all directions from the blast.
2. Blast: 1-megaton Air Burst over Toronto at Yonge and Bloor Explosion causes a pressure pulse = blast Peak Overpressure Distance Effects (14.7 lb/in 2 = 1 atmos) 20 lb/in 2 ~Pape2.9 km -reinforced concrete buildings destroyed; no survivors; 800 kmh wind 10 lb/in 2 ~Dufferin 4.3 km -commercial buildings collapsed; no survivors; 480 kmh wind 5 lb/in 2 ~Victoria Pk6.4 km -brick & wood houses destroyed; 50% fatalities, rest injured; 260 kmh wind (hurricane) 2 lb/in 2 ~Kennedy11 km-significant damage to houses; 50% casualties: 5% dead, rest injured; 115 kmh wind; high fire hazard, destroys 50% buildings 1 lb/in 2 ~Markham Rd16 km-moderate damage to residences; 25% injured (814 km 2 ) (The Effects of Nuclear War, US Office of Technology Assessment, 1979)
3. Radiation sickness Radiation = high-energy particles: gamma (γ) rays, X-rays, neutrons and electrons [beta (β) rays]. Damages cells: can cause sickness or death. Sources: "prompt" radiation from the explosion + "decay" of radioactive fission fragments. Air burst, neutrons and gammas are absorbed on passing through air: only people near the blast centre seriously exposed, and they would die anyway from blast and fire. Ground burst: more serious; n & γ convert nuclei in ground into radioactive nuclei. Blown into air and settle back to earth as "fallout". The radiation from fallout decreases with time - 80% gone in 1 day - 90% gone in the first week - the rest lasts for months
Effects of radiation on humans (from Hodges, Environmental Pollution 1977, and Miller) Radiation dose = sievert,Sv Short-term effects of single-dose, whole-body radiation exposures in humans Less than 0.25 Sv No observable effect About 0.25 Sv Threshold level for detectable effects About 0.5 SvSlight temporary blood changes About 1 SvNausea, fatigue, vomiting. Much higher probability of cancer. Permanent sterility in females and 2 to 3 year sterility in males. 2 to 2.5 SvFatality possible, though recovery is more likely About 5 SvPerhaps one-half of victims would die About 10 SvAll the victims would die
Fig. 2 7-day Fallout from a 1-Megaton Bomb Ground Burst over Toronto At 5 Sv, 50% of exposed people die At 10 Sv, 100% of exposed people die. Peterborough Each dose shown represents the minimum value within that contour, in the absence of any shielding. The exact distribution depends on the wind speed and the terrain. Several bombs totalling much more than 1 MT would be expected for a city the size of Toronto. (The Effects of Nuclear War, US Office of Technology Assessment, 1979)
Fallout Distribution over the USA from an All-out Exchange of Strategic Weapons, US-USSR Shaded = > 10 Sv if no shelter: 100% fatalities. Summary for 10,000 MT war, within 30 days (1980 numbers) -1.1 billion deaths from blast, fire and radiation billion injured Compare world’s population, now ~6 billion. - Includes % of the US population dead if not evacuated. (Recall Hurricane Katrina).
LONG-TERM EFFECTS 1. Nuclear radiation: cancer, leukemia, some genetic damage. In 1984, 2500 people per year still dying prematurely from the radiation from Hiroshima and Nagasaki bombs of In total, this represents about as many people as were killed immediately by those bombs. 2. Nuclear winter (from an all-out war): Science Dec reduction of sunlight to about 5% of normal, blocked by the sooty smoke from burning cities. darkness and sub-freezing temperatures would last for several months, down to -23 o C. a global effect, as the smoke would circulate over most of the world month nuclear winter even if only 2% of the world's nuclear weapons used against cities. Result: if the war in the early spring, then be no summer that year, so no crops for > 1 yr. People surviving the initial radiation would soon have no food. 3. Effects from regional conflict of one hundred 15-kt warheads on cities. Science Mar For example, India vs. Pakistan: 22 million immediate dead in these countries. - Global cooling: e.g., 20 fewer frost-free days in Canadian prairies.
Decrease in frost-free days from kT bombs. Toon et al., Science (2007)
Number of nuclear weapons in the world (+Wikipedia 2006) Country Russia38,00016,000 USA23,29010,000 France?350 China?400? Britain?200 India?40-50 Pakistan?24-48 Israel?70-130? North Korea?~10? MAD = Mutually Assured Destruction = 200
Fig. 4. Global firepower of nuclear weapons in terms of World-War II firepower. The one dot in centre = firepower of WWII = 3 MT. Circle at lower left = 24 MT =firepower on 1 Trident sub. Dots in two squares = destroy all large and medium cities in world. Current global firepower, ~ 0.5 of 1990 ~1990 data
MAJOR TREATIES TO DATE 1963 Limited Test Ban Treaty: no tests in the atmosphere, outer space, under water: Eliminate the spreading of fallout in the atmosphere, which has been responsible for about 11,000 cancer deaths in the USA alone as of Outer Space Treaty: No nuclear weapons in outer space Non-Proliferation Treaty: The 5 nuclear-weapons states (NWS: USA, Russia, England, France, China) agreed to reduce the number of their nuclear weapons (NW) if the other signatories do not develop NW. Affect: Only 4 other countries have developed NW, but the 5 NWS have not seriously reduced their weapons Seabeds Treaty: No nuclear weapons stationed on the seabed Antiballistic missile (ABM) treaty (modified 1976), USA and USSR: The number of missiles stationed to shoot down incoming missiles is limited to a single site in each of USA and Russia (e.g. Moscow). This treaty recognized that ABM's could easily be overcome by building more attacking missiles, leading to a serious arms race.
1976 SALT II (Strategic Arms Limitation Treaty). - Limits number of ICBM (Intercontinental Ballistic Missile) launchers and heavy bombers. - Limits number of warheads on each to 10 for ICBM's and 14 for SLBM's (SL=submarine launched). - Only 1 new ICBM can be developed and built. - Prohibits interference with verification measures, such as concealment Intermediate-Range Nuclear Forces Treaty (INF) - prohibits development and deployment of all land-based (in Europe and Russia) short-, medium- and intermediate-range ballistic missiles (IRBMs) with ranges of 300 to 3,400 miles, as well as all ground-launched cruise missiles Comprehensive Test Ban Treaty (CTBT). Signed by most countries, but not ratified by USA. Bans all NW tests, with the goal of stopping the development of new weapons, and eventually eliminating all weapons as they must be tested periodically. As of July 2002, 165 states signed and 93 ratified. No USA or Russian tests since Middle Powers Initiative: Brazil, Egypt, Ireland, Mexico, New Zealand, South Africa, and Sweden + 8 NGOs. Working to influence NWS to follow the NPT.
RECENT US POLICY CHANGES RE NUCLEAR WEAPONS 2002 ‑ US withdraws from ABM Treaty, to enable it to develop ballistic missile defence (BMD) from "rogue states". (Maybe Alaska from N. Korea?) Result: BMD does not yet work (may never work) but other countries, such as China, now fear a pre ‑ emptive attack from US, so are building more nuclear weapons. (China will increase its military budget 18%; March 2007) Nuclear Posture Review ‑ US includes integrates NW with conventional weapons in its war strategies; assumes it will have NW for next 50 years. ‑ claims the right to use NW to attack any country suspected of developing "weapons of mass destruction“ (nuclear, chemical, biological). ‑ names Iraq, China and N. Korea as possible nuclear targets if they attack neighbours. Potential Result: Signing the NPT is no guarantee that NW will not be used against you, so why not develop NW? Terrorist danger from nuclear weapons increases with the number of nuclear weapons states Bush threatens to withdraw from the CTBT as the US is developing the NW "robust earth penetrator" as a "bunker buster", which is nearing completion. However, in 2005, Senate denied more funding for this project (March) Russia threatens to withdraw from the INF (Intermediate Nuclear Forces) Treaty as USA plans ABM system in Europe. Overall result: world is now in much more danger from NW use and proliferation than before 2002.
SOME CANADIAN PEACE ORGANIZATIONS: -Project Ploughshares, (Kawartha Ploughshares in Peterborough, Dr. Joyce Barrett ).http://www.ploughshares.ca/ (Day of Action, March 17, Iraq & Afghanistan, Confederation Park, 1 PM) -Physicians for Global Survival, -Ceasefire, -Science for Peace (Main office at U. of Toronto); encourages student groups.http://scienceforpeace.sa.utoronto.ca/