Nuclear 2 by RANA SAIFULLAH KHAN

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Nuclear 2 by RANA SAIFULLAH KHAN

  1. 1. CLASSIFICATION OF NUCLEAR REACTORS TYPES OF FISSION • SLOW REACTORS OR THERMAL REACTORS – REACTOR CORE IS LARGE AND HEAVIER – THEY HAVE LONG NEUTRON LIFE AND LOW POWER DENSITY SO CONTROL IS EASIER – LOW FUEL LOADING – IT IS IMPOSSIBLE TO BREED – LOW COOLING PROBLEMS • FAST REACTORS – FISSION CAUSED BY FAST NEUTRON BUT THEIR SPEED REDUCED BY MODERATOR – HIGH FISSION RATE AND HIGH BREEDING – SMALL IN SIZE AND COMPACT – EASIER TO SHIELD – HIGH POWER DENSITY ( KW/m3)RESULTS IN COOLING AND HT PROBLEMS
  2. 2. TYPES OF FUEL • NATURAL URANIUM – FISSIONABLE U 235 AND FERTILE U 238. SO PU 239 IS PRODUCED AND U 233 FROM THORIUM 232 ARE PRODUCED ARTIFICALLY FROM A FERTILE MATERIAL BY NEUTRON REACTION. FUEL CYCLES • BURNER REACTOR - ONLY HEAT IS PRODUCED WITHOUT CONVERSION • CONVERTOR REACTOR – MATERIAL CONVERTED BY PUTTING FERTILE MATERIAL IN CORE U 238 TO PU 239. • BREEDER REACTOR – PU 239 IS THE FUEL AND U 238 CONVERTED TO PU
  3. 3. Breeder reactor • r= no of fuel atoms formed/ no of original fuel atoms consumed in fission ; r<1 convertor if r > 1 then breeder ( 7 to 15 yrs to produce fuel for another reactor) • Breeder generated energy and also produces fuel than it consumes.
  4. 4. STATE OF FUEL • SOLID OR LIQUID- MOSTLY SOLID BUT MAY BE MIXED WITH URANIUM OXIDE TO FORM SLURRY IN WATER OR LIQUID METAL. SO ITS CALLED LIQUID METAL FUELED REACTOR( LMFR)-SGR – PERMITS HIGH TEMP, PRESSURIZATION SOLVED. • POSITION OF FERTILE AND FISSILE MATERIAL RELATIVE POSITION TO EACH OTHER IN REACTOR CORE.
  5. 5. CHOICE OF MODERATOR • TYPES OF MODERATOR ; GRAPHITE , NATURAL WATER AND HEAVY WATER . GRAPHITE HAS HIGHER ATOMIC WEIGHT THAN WATER SO THEY ARE BULKY. NATURAL WATER GIVES A SMALL AND COMPACT REACTOR. CORE COMPOSITION
  6. 6. METHOD OF COOLING • DIRECT COOLING AND INDIRECT COOLING • ORDINARY WATER IS USED WITH ENRICHED URANIUM AND HEAVY WATER WITH ORDINARY URANIUM DUE TO THEIR NEUTRON ABSORPTION CAPABILITY • LOW NEUTRON ABSORPTION
  7. 7. GAS COOLED REACTOR • GAS IS CIRCULATED THROUGH REACTOR CORE TO COOL THE REACTOR.AIR ,HE ,HYDROGEN OR CO2. • POOR HEAT TRANSFER OF GASES REQUIRE HIGH PUMPING POWER. • CORROSION PROBLEMS RESOLVED • POWER DENSITY IS LOW
  8. 8. WATER COOLED REACTOR • LIGHT WATER REACTOR- HAS GOOD THERMAL PROPERTIES, CHEAP COOLANT, BUT IT HAS CORROSION ISSUES AND DUE TO NEUTRON ABSORPTION MAY INTERRUPT CRITICALITY. • BWR-BOILING WATER REACTOR
  9. 9. • WATER CONVERTS TO STEM AND DIRECTLY IMPINGES ON TURBINE • STEAM LEAVING REACTOR MAY BE RADIOACTIVE AND PIPING AND STEAM TURBINE
  10. 10. PRESSURIZED WATER REACTOR • WATER IS PRESSURIZED TO PREVENT BULK BOILING AT 150 ATM. • HOT WATER FROM REACTOR FLOWS TO STEAM GENERATOR (HX)WHERE ITS HEAT IS TRANSFERRED TO FEED WATER TO GENERATE STEAM.
  11. 11. • STEAM IS PRODUCED AT 7.5 TO 8 Mpa AND 320 C. • PWR ARE STABLE. • TURBINE LOOP SEPARATE THAN PRIMARY SO LESS CHANCES OF RADIOACTIVE. • THE LIQUID SHOULD BE HIGHLY PRESSURIZED TO REMAIN LIQUID AT HIGH TEMP.SO HIGH COST PIPE
  12. 12. COOLANT • COOLANT PICKS UP HEAT AND KEEP FUEL ASSEMBLIES AT SAFE TEMP TO AVOID DESTRUCTION AND MELTING. • AIR,HELIUM,WATER,CO2,H2,NA ,K, • IT SHOULD HAVE REALISTIC FLUIDITY FOR HT. • LOW ABSORTION OF NEUTRON • IF COMPOUND,STABILITY FROM DISASSOCIATION • SPECIFIC HEAT ANG K SHOULD BE HIGH TO HT. • NON CORROSIVE • THERMAL STABILITY
  13. 13. NEW TRENDS • ORGANIC SUBSTANCE COOLED REACTORS ,OIL,PETROLEUM • CAN OPERTAE AT HIGH TEMP WITH MODERATE PRESSURE.SO LIGHTER EQUP,DEVICES ,PIPES( ORDINARY STEEL ) AND REDUCED COST. • LESS CORROSIVE THAN WATER • H2 CONTENTS MAKES THEM ACCEPTABLE AS MODERATORS • THESE DON’T BECOME RADIOACTIVE AS NEUTRON BOMBARDMENT. • DON’T FREEZE AT LOW TEMP SO GOOD FOR USE IN COLD REGIONS
  14. 14. FUEL CYCLE
  15. 15. GASES DIFFUSION
  16. 16. CENTRIFUGAL/ THERMAL DIFFUSION
  17. 17. ELECTROMAGNETIC DIFFUSION

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