2. NUCLEAR REACTOR
IT IS THE APPARATUS IN WHICH NUCLEAR
FISSION IS PRODUCED IN THE FORM
OF A CONTROLLED SELF-SUSTAINING CHAIN
REACTION.
3. GAS COOLED REACTOR DEFINITION
GAS COOLED REACTOR IS A NUCLEAR
REACTOR WHICH USES GRAPHITE AS
MODERATOR AND GAS AS COOLANT .
COOLANT GAS USED MAY BE CARBON
DIOXIDE OR HELIUM.
4. TYPES OF GAS COOLED REACTOR
THERE ARE TWO TYPES OF GAS COOLED REACTOR :-
1. GAS COOLED GRAPHITE MODERATOR REACTOR (GCGM)
2. HIGH TEMPERATURE GAS COOLED REACTOR ( HTGC)
5. GAS COOLED GRAPHITE MODERATOR
REACTOR
IT USES GRAPHITE AS MODERATOR AND NATURAL URANIUM AS FUEL .
GENERALLY GENERATION OF GAS COOLED GRAPHITE MODERATOR REACTOR
COMPRISES OF TWO TYPES OF GENERATION :-
1. MAGNOX REACTOR INVENTED BY BRITAIN
2. UNGG REACTOR INVENTED BY FRANCE
COOLANT PRESSURE AND TEMPERATURE IN GCGM IS ABOUT 7 bar 336 degree C .
7. HIGH TEMPERATURE GAS COOLED REACTOR
HTGC COMPOSED OF URANIUM CARBIDE MIXED WITH THORIUM CARBIDE
CLADDED WITH GRAPHITE.
COOLANT PRESSURE AND TEMPERATURE IN HTGC IS ABOUT 15 bar to 30 bar
700 degree C TO 800 degree C .
8. ADVANTAGES OF GAS COOLED REACTOR
1. PROCESSING OF FUEL IS SIMPLER.
2. NO CORROSION PROBLEM .
3. GRAPHITE REMAINS STABLE UNDER IRRADIATION AT HIGH TEMPERATURE.
4. USE OF CO^2 AS COOLANT COMPLETELY ELIMINATES THE POSSIBILITY OF
EXPLOSION IN THE REACTOR WHICH IS ALWAYS PRESENT IN WATER
COOLED PLANTS.
5. URANIUM CARBIDE AND GRAPHITE ARE ABLE TO RESIST HIGH
TEMPERATURES.
9. DISADVANTAGES OF GAS COOLED REACTOR
1. FUEL LOADING IS COSTLY.
2. DUE TO HIGH CRITICAL MASS LARGE AMOUNT OF FUEL LOADING IS
INITIALLY REQUIRED.
3. IF HELIUM IS USED INSTEAD OF Co^2 THEN LEAKAGE MAY OCCUR.
4. CONTROLLLING THESE REACTORS IS A COMPLICATED TASK.