DESIGING A NUCLEAR WEAPON

WHEN MOST PEOPLE THINK NUCLEAR ENERGY, THEY THINK BOMB. THEY THINK, “OH, MY GOSH, TERRORIST ARE GOING TO STEAL THE FUEL AND MAKE A WEAPON OR A DIRTY BOMB.” LET’S CONSIDER BOTH POSSIBILITIES. NATURAL URANIUM IS 0.7% U235 WITH THE REMAINDER BEING U238. TO FUEL A NUCLEAR REACTOR, WE NEED 3.5% U235. TO MAKE A BOMB, WE NEED AT LEAST 90% U235. SEPARATING U238 FROM U235 IS VERY DIFFICULT.

YOU ARE DEALING WITH TWO ISOTOPES OF ALMOST IDENTICAL ATOMIC MASS. THE CHEMISTRIES ARE IDENTICAL. THE ONLY THING THAT IS DIFFERENT IS ATOMIC MASS, AND THAT DIFFERENCE IS VERY SMALL. TWO METHODS ARE CURRENTLY USED. 1) GAS DIFFUSION – URANIUM OXIDE IS CONVERTED TO A LOW BOILING LIQUID, URANIUM FLUORIDE, UF 6. THIS IS HEATED TO CONVERT IT TO A GAS, AND THE GAS IS ALLOWED TO DIFFUSE THROUGH A POROUS MEMBRANE. THE U235 DIFFUSES SLIGHTLY FASTER, SO THE GAS EMERGING FROM THE MEMBRANE WILL BE RICHER IN U235. THE ENRICHMENT IS VERY SLIGHT, SO HUNDREDS OF BARRIERS MUST BE USED.

2. GAS CENTRIFUGE – AGAIN, THE URANIUM IS CONVERTED TO UF 6. THIS IS CONVERTED TO A GAS AND PUMPED INTO A CENTRIFUGE WITH A HIGH SPEED ROTOR (70,000 RPM). THE U238 TENDS TO MOVE TO THE OUTSIDE OF THE CHAMBER, AND THE U235 WILL BE LEFT IN THE CENTER. THE SEPARATION IS NOT FAST. TYPICALLY, SEVERAL HUNDRED OF THESE WOULD BE USED IN SERIES AND IN PARALLEL. IT TAKES A VERY LONG TIME WITH EITHER OF THESE METHODS TO COLLECT ENOUGH U235 TO FUEL A REACTOR OR TO MAKE A BOMB.

PLUTONIUM 239 CAN ALSO BE USED TO MAKE A NUCLEAR WEAPON. IT IS NOT NATURALLY OCCURING, BUT IT IS MADE THROUGH NEURTON ABSORPTION IN CONVENTIONAL NUCLEAR REACTORS. PLUTONIUM IS DIFFERENT ENOUGH CHEMICALLY FROM URANIUM THAT IT CAN BE CHEMICALLY SEPARATED. THIS IS WHY SO MANY PEOPLE ARE AGAINST REPROCESSING SPENT FUEL FROM NUCLEAR REACTORS. REPROCESSING WAS BANNED IN THE U.S. UNDER THE CARTER ADMINISTRATION. PLUTONIUM FROM REPROCESSING IS USUALLY BLENDED BACK WITH URANIUM 238 TO PREVENT THE DEVELOPMENT OF NUCLEAR WEAPONS. THEN IT IS USED IN REACTORS.

TO MAKE A WEAPON, YOU NEED A SUPERCRITICAL MASS OF EITHER U235 OR Pu239. THIS IS THE MASS THAT WOULD GENERATE AN EXPONENTIAL RELEASE OF NEUTRONS AND AN EXPLOSION. WITH U235, THIS IS APPROXIMATELY 10 POUNDS. THE MATERIAL MUST BE BROUGHT TOGETHER FAST ENOUGH TO CREATE AN EXPLOSION BEFORE THE WEAPON CONSUMES ITSELF. THIS IS LESS THAN ONE MILLISECOND. BOMBS HAVE USED THE COMPRESSION METHOD AND THE GUN METHOD. IN THE GUN METHOD, ONE MASS OF URANIUM IS FIRED INTO A SECOND MASS.

IN THE IMPLOSION METHOD, THE FUEL IS COMPRESSED INTO A SPHERE USING EXPLOSIVE CHARGES.

HYDROGEN BOMBS OR THERMONUCLEAR DEVICES USE THE X-RAYS AND GAMMA RAYS FROM A FISSION EXPLOSION TO COMPRESS AND IGNITE TRITIUM, DEUTERIUM, OR LITHIUM DEUTERIDE IN A FUSION REACTION. THIS CAN EASILY DOUBLE THE POWER OF A BOMB. THE LARGEST BOMB EVER EXPLODED WAS A HYDROGEN BOMB BUILT BY THE RUSSIANS THAT EXPLODED WITH A FORCE OF 50 MEGATONS (50 MILLION TONS OF TNT). THE BOMB DROPPED ON HIROSHIMA, “LITTLE BOY”, HAD A FORCE OF 15 KILOTONS. IT KILLED 140,000 PEOPLE. AT THE BEGINNING OF THE LAST DISARMAMENT TREATY, THE U.S. AND RUSSIA EACH HAD ABOUT 15,000 WEAPONS EACH.

LITTLE BOY 8,900 POUNDS, 3 METERS LONG

VARIATIONS: NEUTRON BOMB – BUILT TO PRODUCE LARGE AMOUNTS OF NEUTRONS, BUT WITH SMALL EXPLOSIVE POWER. THE NEUTRONS WOULD CAUSE LARGE NUMBERS OF CASUALTIES, BUT LITTLE PHYSICAL DAMAGE WOULD BE DONE, AND ONLY A SMALL AMOUNT OF RADIOACTIVE CONTAMINATION WOULD RESULT. THE AREA COULD BE QUICKLY OCCUPIED. DELIVERY SYSTEMS NOW VARY FROM AIRPLANES TO MISSILES, CANNON, TORPEDOES, MORTARS, AND A TWO-MAN DEMOLITION DEVICE (SOMETIMES REFERRED TO AS A SUITCASE BOMB)

U.S. PEACEKEEPER MISSLE (MULTIPLE INDEPENDENTLY TARGETABLE REENTRY VEHICLES) MIRVs

DIRTY BOMB – A CONVENTIONAL BOMB SURROUNDED BY HIGH LEVEL NUCLEAR WASTE. 1)GETTING AND HANDLING THE HIGH LEVEL WASTE WOULD BE EXTREMELY DANGEROUS 2)IT WOULD BE EASILY DETECTABLE 3)AFTER DISPERSAL, THE CONTAMINATION WOULD BE EASY TO DETECT AND CLEAN UP, AS TO SAY, DISPERSING A DEADLY VIRUS OR MICROORGANISM, WHICH WOULD BE ALMOST IMPOSSIBLE TO DETECT AND LOCATE

COUNTRIES WITH NUCLEAR WEAPONS: U.S. RUSSIA FRANCE U.K. CHINA INDIA ISRAEL PAKISTAN NORTH KOREA SOUTH AFRICA (fmr.)