Free Chemical Process Principles MCQs with Answers
2,710 Chemical Process Principles MCQs from Chemical Engineering, each with the correct answer and a written explanation of why it is correct. Free and unlimited, with no account needed.
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- A. Coolant
- B. Both A. & B.
- C. Moderator
- D. Neutron absorber
Explanation: Heavy water can perform both functions: it removes heat as a coolant and slows neutrons as a moderator.
Correct answer: Both A. & B.- A. Much more
- B. More
- C. Same
- D. Less
Explanation: The fission products have slightly less combined mass than the original nucleus.
Correct answer: Less- A. Kinetic
- B. Thermal
- C. Potential
- D. Electrical
Explanation: Most nuclear-fission energy first appears as kinetic energy of the rapidly moving fission fragments and neutrons.
Correct answer: Kinetic- A. 1.44 T
- B. 0.144 T
- C. 14.4 T
- D. 2T
Explanation: For radioactive decay, mean life is 1/λ, while half-life is ln 2/λ. Therefore, mean life = T/ln 2 ≈ 1.44T.
Correct answer: 1.44 T- A. Fuel is natural uranium and heavy water acts both as moderator & coolant
- B. Coolant water boils in the core of the reactor
- C. Coolant water is pressurised to prevent bulk boiling of water in the core
- D. Use of moderator is not required
Explanation: PWR water is kept under high pressure so its boiling point rises and bulk boiling does not occur inside the reactor core.
Correct answer: Coolant water is pressurised to prevent bulk boiling of water in the core- A. Fissioned by either slow or fast neutrons
- B. Fissioned by slow (thermal) neutrons
- C. Fissioned by fast neutrons
- D. Converted into fissile material on absorption of neutron
Explanation: A fertile material is not normally fissile itself but can absorb a neutron and transform into a fissile isotope, such as U-238 becoming…
Correct answer: Converted into fissile material on absorption of neutron- A. Fuel & moderator
- B. Fuel & coolant
- C. Coolant & moderator
- D. None of these
Explanation: In a homogeneous reactor, the fuel is uniformly mixed with the moderator, forming a single homogeneous reactor medium.
Correct answer: Fuel & moderator- A. Combustion of a nuclear fuel e.g. uranium
- B. Fusion of atoms of uranium
- C. Fission of U-235 by neutrons
- D. Absorption of neutrons in uranium atoms
Explanation: A thermal reactor produces heat mainly through the fission of U-235 after absorption of neutrons.
Correct answer: Fission of U-235 by neutrons1369. Molten sodium is used as a coolant in a fast breeder reactor, because of its_________________?
- A. Excellent moderating properties
- B. Neutron breeding capability
- C. Capability to increase the reaction rate in the core
- D. Faster heat removal capability from the core
Explanation: Liquid sodium has excellent thermal conductivity and heat-transfer performance, allowing rapid removal of core heat.
Correct answer: Faster heat removal capability from the core- A. Fissile atoms are evenly distributed throughout the mass of nuclear reactor
- B. Same substance (e.g. heavy water) is used as moderator & coolant
- C. The fuel and the moderator is mixed to form a homogeneous material
- D. All A., B. and C.
Explanation: A homogeneous reactor has fuel and moderator mixed uniformly to form one homogeneous material.
Correct answer: The fuel and the moderator is mixed to form a homogeneous material- A. 141
- B. 92
- C. 233
- D. 325
Explanation: The mass number equals protons plus neutrons, so the neutron count is 233 − 92 = 141.
Correct answer: 141- A. Proton
- B. α-particle
- C. Electron
- D. Neutron
Explanation: A positron is the antimatter counterpart of an electron and has the same mass, but opposite electric charge.
Correct answer: Electron- A. 1/2
- B. 1/4
- C. 1/8
- D. 1/16
Explanation: Four half-lives pass in 400 years because 400/100 = 4. The remaining fraction is (1/2)^4 = 1/16 of the original amount.
Correct answer: 1/16- A. Nucleons
- B. Electrons
- C. Neutrons
- D. Protons
Explanation: Nuclei with many nucleons, especially heavy nuclei such as uranium-235, are more susceptible to fission because their large size makes the…
Correct answer: Nucleons- A. 9.31 MeV
- B. 931 eV
- C. 931 Mev
- D. 931 J
Explanation: The mass-energy equivalent of 1 atomic mass unit is approximately 931 MeV, obtained from E = mc².
Correct answer: 931 Mev- A. 3/4
- B. 1/6
- C. 3
- D. 4
Explanation: If 75% decays, 25% remains, which is one-fourth of the original amount or two half-lives.
Correct answer: 3- A. Zircaloy
- B. Stainless steel
- C. Ceramics
- D. Cadmium
Explanation: Cadmium strongly absorbs neutrons, so it is used in control rods rather than as fuel cladding.
Correct answer: Cadmium- A. Iodine
- B. Cobalt
- C. Iron
- D. Carbon
Explanation: Radioactive iodine is concentrated by the thyroid because the gland uses iodine to synthesize thyroid hormones, allowing iodine isotopes…
Correct answer: Iodine- A. 58
- B. 98
- C. 348
- D. 588
Explanation: Sodium melts at about 97.8°C at atmospheric pressure, which rounds to 98°C.
Correct answer: 98- A. Requires less fuel to run at the same power level
- B. Uses faster neutrons for fission
- C. Gives higher power density
- D. Uses slower neutrons for fission
Explanation: A thermal reactor uses a moderator to slow neutrons, because slow neutrons have a higher probability of causing fission in fuels such as…
Correct answer: Uses slower neutrons for fission