2501. Moderator in nuclear plants is used to__________________?
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A. reduce temperature

B. moderate the radioactive pollution

C. control the reaction

D. extract heat from nuclear reaction

E. cause collision with the fast moving neutrons to reduce their speed
2502. The energy required to be applied to a radioactive nucleus for the emission of a neutron is________________?
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A. 1 MeV

B. 4.3 MeV

C. 20 MeV

D. 7.8 MeV

E. 2.4 MeV

2503. Which of the following are ferrite materials__________________?
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A. U233andPu239

B. U

C. U238andTh239

D. none of the above

E. U238andPu239

2504. Ideally the neutron flux in reactor should be__________________ ?
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A. uniform throughout

B. maximum in center and zero at side

C. maximum at side and zero in center

D. zero throughout

E. none of the above

2505. The nuclear power plant at Tarapur has the following reactor________________?
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A. pressurised water

B. fast breeder

C. sodium graphite

D. none of the above

E. boiling water
2506. U235 will undergo fission by__________________?
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A. either fast or slow neutrons

B. low energy (slow) neutrons alone

C. high energy (fast) neutrons alone

D. none of the above

E. medium energy neutrons

2507. Half life of a radioactive isotope corresponds to the time required for half of the following to decay__________________?
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A. protons

B. electrons

C. neutrons

D. nulceus

E. atom
2508. A fission chain reaction in uranium can be developed by________________?
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A. using moderator

B. absorbing all neutrons

C. slowing down fast neutrons so that Uz fission continues by slow motion neutrons

D. accelerating fast neutrons

E. enriching U235

2509. Plutonium is produced________________?
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A. by neutron irradiation of Uz

B. in high capacity furnace

C. as basic raw material

D. by neutron irradiation of throium

E. artificially

2510. A fast breeder reactor uses following as fuel_________________?
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A. natrual uranium

B. enriched uranium

C. U235

D. plutonium

E. thorium

2511. Uranium-233 is produced__________________?
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A. by neutron irradiation of Uz

B. by neutron irradiation of thorium

C. as basic raw material

D. in high capacity furnaces

E. artificially

2512. In order to have constant clain reaction to produce a constant rate of heat output, the value of ratio of the number of neutrons in one generation to the number of neutrons in the immediately preceding generation must be________________?
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A. less than 1.0

B. greater than 1.0

C. equal to zero

D. equal to 1.0

E. equal to infinity

2513. A fast breeder reactor__________________?
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A. uses graphite rods as moderator

B. uses ferrite material as moderator

C. has no moderator

D. has powerful moderator

E. uses pressurised water as moderator

2514. In triggering fission, the following types of neutrons are desirable_________________?
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A. fast moving

B. neutrons at rest

C. slow moving

D. critical neutrons

E. none of the above

2515. The presence of reflector in nuclear power plants results in___________________?
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A. increased production of neutrons

B. controlled production of neutrons

C. complete absorption of neutrons

D. decrease of speed of neutrons

E. decreased leakage of neutrons
2516. The risk of radioactive hazard is greatest in the turbine with following reactor___________________?
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A. all of the above.

B. boiling water

C. liquid metal cooled

D. gas cooled

E. pressurised water

2517. Which of the following can be used as a coolant in nuclear plant________________?
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A. light or heavy water

B. carbon tetrachloride

C. freon

D. carbon dioxide

E. molten lead

2518. In the breeder reactors the generation of new fissionable atom is_________________?
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A. at a higher rate than the constuption

B. unpredictable

C. at the lower rate than the consumption

D. depends on other considerations

E. at an equal rate of the consumption

2519. The function of control rods in nuclear plants is to__________________?
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A. control absorption of neutron

B. readioactive pollution

C. none of the above

D. control temperature

E. control fuel consumption

2520. The fuel needed, with reflector in nuclear power plant, in order to generate sufficient neutrons to sustain a chain reaction, would be________________?
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A. less

B. zero

C. more

D. same

E. negative, i.e. fuel would be generated

2521. Supertheated steam is generated in following reactor________________?
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A. all of the above

B. gas cooled

C. boiling water

D. pressurised water

E. none of the above

2522. Which of the following is secondary fuel ?
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A. non oh these

B. U233andPu238

C. U233andPu239

D. Th232andU238

2523. Pick up the wrong statement Fast breeder reactors__________________?
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A. are unmoderated

B. are liquid-metal cooled

C. produce more fuel than they consume

D. use water as coolant

E. operate at extremely high power densities.

2524. Enriched uranium may contain fissionable contents of the order of__________________?
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A. 1-90%.

B. 1-50%

C. 1-75%

D. 1-25%

E. 1-99%
2525. In a fission process, maximum %age of energy is released as___________________?
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A. gradual readioactive decay of fission products

B. kinetic energy of neutrons

C. none of the above

D. instantaneous release of gamma rays

E. kinetic energy of fission products
2526. Which of the following is more appropriate for a moderator. One which_________________?
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A. absorbs neutrons

B. regenerates neutrons

C. does not absorb neutrons

D. accelerates neutrons

E. eats up neutrons

2527. Breeder reactors employ liquid metal coolant because it_______________?
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A. produces maximum steam

B. breeds neutrons

C. transfers heat from core at a fast rate

D. acts as good moderator

E. increases rate of reaction in core

2528. Solid- fuel for nuclear reactions may be fabricated into various small shapes such as___________________?
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A. any one of the above

B. plates

C. pins

D. none of the above

E. pallets

2529. The size of the reactor is said to be critical when_________________?
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A. chain reaction can be initiated

B. it produces no power

C. it explodes

D. it produces tremendous power

E. it becomes uncontrollable

2530. Each fission of U235 produces following number of fast neutrons per fission________________?
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A. 1 neutrons

B. infinite

C. 2 neutrons

D. 1 neutron

E. 1 2 neutrons

2531. In triggering fission, which type of neutrons are more effective_________________?
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A. activated

B. static

C. in bulk

D. slow

E. fast

2532. The coolant used in boiling water reactor is________________?
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A. Co2

B. mixture of water and steam

C. liquid metal

D. mercury

E. pressurised water

2533. The most practical fuel for a thermo-nuclear reactor, both from econocical and nuclear consideration is____________________?
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A. thorium

B. lithium

C. deuterium

D. uranium

E. plutonium

2534. Which of the following type of pump is used in liquid metal cooled reactor for circulation of liquid metal_________________?
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A. reciprocation

B. axial

C. electromagnetic

D. diaphragm

E. centrifugal

2535. The energy produced by a thermal reactor of same size as a breeder reactor is__________________?
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A. much more.

B. slightly less

C. almost same

D. slightly more

E. much less
2536. A fast breeder reactor uses_______________?
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A. U-239

B. Pu-239

C. U-238

D. 90% U-235

E. U-235

2537. Which of the following is the primary fuel________________?
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A. U

B. U238

C. Pu

D. Pu:

E. Ulii

2538. The unit of radio-activity is_____________?
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A. curie

B. electron-ampere

C. AMU

D. electron-volt

E. MeV

2539. A boiling water reactor uses following as fuel________________?
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A. plutonium

B. thorium

C. enriched uranium

D. natural uranium.

E. U

2540. Reactors for propulsion applications use_________________?
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A. natural uranium

B. molten lead

C. thorium

D. any form of uranium

E. plutonium

2541. Reactors designed for propulsion applications are designed for_______________?
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A. enriched uranium

B. pure uranium

C. none of the above

D. natural uranium

E. any type of uranium

2542. Pressurised water reactor is designed________________?
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A. to prevent the water coolant from boiling in the core

B. to use intermediate coolant

C. for boiling pi water in the core

D. to eliminate the coolant loop of the pressurised water

E. to use liquid sodium metal as coolant

2543. Pick up the wrong statement?
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A. In a heterogeneous or solid-fuel reactor, the fuel is mixed in a regular pattern within moderator.

B. Most serious drawback in using water as coolant in nuclear plants is its high vapour pressure

C. Slow or thermal neutrons have energy of the order or 0.025 eV

D. Fast neutrons have energies above 1000 eV

E. Fast reactor uses moderator
2544. Effective moderators are those materials which contain____________________?
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A. heavy weight atoms

B. there is no such criterion

C. zero weight atoms

D. critical atoms

E. light weight atoms
2545. The following present serious difficulty in designing reactor shield_________________?
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A. alpha particles

B. beta particles

C. thermal neutrons

D. fast neutrons and gamma rays

E. none of the above

2546. A pressurised water reactor employs pressuriser for the following application________________?
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A. to Supply high pressure steam

B. to increase pressure of water in primary circut

C. all of the above

D. to maintain constant pressure in primary circuit under varying load

E. to provide subcooled water at high pressure

2547. When a reactor becomes critical, then the production of neutrons is_________________?
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A. zero

B. stopped

C. initiated

D. exactly balanced by the loss of neutrons through leakage

E. infinite

2548. In nuclear fission___________________?
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A. the original elements change into completely different elements

B. none of the above

C. the molecules rearrange themselves to form other molecules

D. strong>. the electrons of the element change

2549. Plutonium-239 is produced__________________?
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A. by neutron irradiation of IT*

B. by neutron irradiation of thorium

C. as basic raw material

D. in high capacity furnaces

E. artificially

2550. The efficiency of a nuclear power plant in comparison to conventional and nuclear consideration is__________________?
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A. lower temperature and pressure condi-tions

B. nuclear hazard risk

C. high initial cost

D. higher cost of nuclear fuel

E. high heat rejection in condenser