How does the velocity of sound in gas varies with change in ratio of specific heats, absolute temperature, and specific gravity ?

How does the velocity of sound in gas varies with change in ratio of specific heats, absolute temperature, and specific gravity ?
Ans: Velocity of sound in a gas varies directly as  ^ratio of specific heats , directly as absolute temperature , and inversely as ^/specific gravity .

Which parameter remains constant in a throttling process ?

Which parameter remains constant in a throttling process ?
Ans. Enthalpy.

Why water can't be used as refrigerant for small refrigerating equipment ?

Why water can't be used as refrigerant for small refrigerating equipment ?
Ans. The refrigerant should be such that vapour volume is low so that pumping work will be low. Water vapour volume is around 4000 times compared to R-22 for a given mass.

Under what circumstances would there be an increase in pressure in a divergent nozzle ?

Under what circumstances would there be an increase in pressure in a divergent nozzle ?
Ans. For subsonic flow at inlet section of a diffuser a lower velocity and higher pressure will exist at the exit section. For supersonic isentropic flow at the inlet section a higher velocity and lower pressure will exist at the exit but if a shock wave occurs in the diffuser then a higher pressure will exist at the exit.

Why an increase in area is required to produce an increase of velocity in case of supersonic flow ?

Why an increase in area is required to produce an increase of velocity in case of supersonic flow ?
Ans. Increase in area for increase in velocity for supersonic flow is required because the density decreases faster than velocity increases at supersonic speeds and to maintain continuity of mass, area must increase.

Which reactor uses primary coolant as fluoride salts of lithium, beryllium, thorium and uranium ?

Which reactor uses primary coolant as fluoride salts of lithium, beryllium, tho¬rium and uranium ?
Ans. Molten salt breeder reactor.

Which reactor requires no moderator ?

Which reactor requires no moderator ?
Ans. Breeder reactor.

Which reactor uses heavy water as moderator ?

Which reactor uses heavy water as moderator ?
Ans. CANDU.

Which reactor uses natural uranium as fuel ?

Which reactor uses natural uranium as fuel ?
Ans. Gas cooled reacator.

Which reactor produces more fissionable material than it consumes ?

Which reactor produces more fissionable material than it consumes ?
Ans. Breeder reactor.

Which nuclear reactor uses water as a coolant, moderator and reflector ?

Which nuclear reactor uses water as a coolant, moderator and reflector ?
Ans. Pressurised water reactor.

Disposal of radioactive waste materials and spent fuel is a major and important technology. How the waste radioactive material is disposed off ?

Disposal of radioactive waste materials and spent fuel is a major and important technology. How the waste radioactive material is disposed off ?
Ans. Nonusable fission products are radioactive and take short/medium/long time for radioactive decay to reach safe level of radioactivity. Accordingly three methods of disposal are :
(a) Zero or low radioactivity material is dispersed or stored without elaborate shielding.
(b) Medium radioactivity material is stored for short duration of about 5 years to allow decay of radioactivity.
(c) High radioactive material. They are stored in water for several months to permit radioactive decay to an accepetable low level.

What is the difference between conversion and enrichment ?

What is the difference between conversion and enrichment ?
Ans. The process of converting the non fissile U 238 to fissile U-235 is also called "Conver¬sion". The material like U 238 which can be converted to a fissile material by the neutron flux is called "fertile material". The conversion is obtained within the nuclear reactor during the chain reac¬tion.
Enrichment is the process by which the proportion of fissile uranium isotope (U-235) is in¬creased above 0.7% (original % in natural uranium).
The concentration of U-235 in the uranium hexafluoride is increased from the 0.7% in natural uranium to 2 to 4%. This is called enrichment and is accomplished in an enrichment plant.

Explain nuclear reactor in brief.

Explain nuclear reactor in brief.
Ans. A plant which initiates, sustains, controls and maintains nuclear fission chain reaction and provides shielding against radioactive radiation is nuclear reactor.

What is a converter reactor ?

What is a converter reactor ?
Ans. A reactor plant which is designed to produce more fuel than it consumes. The breeding is obtained by converting fertile material to fissile material.

What is heavy water and what is its use in nuclear plants ?

What is heavy water and what is its use in nuclear plants ?
Ans. Water containing heavy isotopes of hydrogen (Deuterium) is known as heavy water. Heavy water is used as a moderator. Heavy water has low cross section for absorption of neutrons than ordinary water. Heavy water slows down the fast neutrons and thus moderates the chain reaction.

What do you understand by fuel cycle in nuclear plants ?

What do you understand by fuel cycle in nuclear plants ?
Ans. Fuel cycle a series of sequential steps involved in supplying fuel to a nuclear power reac¬tor. The steps include : Mining, refining uranium, fabrication of fuel elements, their use in nuclear reactor, chemical processing to recover remaining fissionable material, re-enrichment of fuel from re¬covered material, refabrication of new fuel elements, waste storage etc.

Explain difference between fissile and fertile materials.

Explain difference between fissile and fertile materials.
Ans. The materials which can give nuclear fission e.g. U 235, Pu 239, U 233 are fissile materials. Fertile material itself is not fissionable, but it can be converted to a fissionable material by irradiation of neutrons in a nuclear reactor.

What is the difference between nuclear fission and fission chain reaction.

What is the difference between nuclear fission and fission chain reaction.
Ans. The process of splitting of nucleus into two almost equal fragments accompanied by re¬lease of heat is nuclear fission. Self sustained, continuing, sequence of fission reactions in a con¬trolled manner is fission chain reaction.

How the analyses and calorific values of fuels can be reported ?

How the analyses and calorific values of fuels can be reported ?
Ans. It may be reported as
(a) as received or fired (wet) basis
(b) dry or moisture free basis
(c) combustible or ash and moisture free basis