Nuclear Field Qualification Exams
(Navy) Exam Practice Questions And
Correct Answers (Verified Answers) Plus
Rationale 2026 Q&A| Instant Download
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1. Which type of nuclear reaction primarily powers a naval pressurized
water reactor?
A. Chemical combustion
B. Nuclear fission
C. Nuclear fusion
D. Radioactive decay
B. Nuclear fission
Nuclear fission is the process in which heavy atomic nuclei split into
lighter nuclei, releasing large amounts of energy used in naval
reactors.
2. What is the primary role of the moderator in a nuclear reactor?
A. Absorb all neutrons
B. Increase neutron speed
C. Slow down neutrons to sustain chain reaction
D. Produce fuel rods
C. Slow down neutrons to sustain chain reaction
The moderator reduces neutron energy, increasing the likelihood of
further fission events in fissile material.
,3. Which material is most commonly used as fuel in naval reactors?
A. Uranium-235
B. Carbon-12
C. Thorium-232
D. Lead-208
A. Uranium-235
Uranium-235 is a fissile isotope widely used in naval nuclear
propulsion due to its ability to sustain a controlled chain reaction.
4. What is the function of control rods in a reactor core?
A. Increase reactor temperature
B. Absorb excess neutrons to control reaction rate
C. Cool the reactor coolant
D. Generate steam directly
B. Absorb excess neutrons to control reaction rate
Control rods regulate reactor power by absorbing neutrons and
thereby controlling the fission rate.
5. What is the primary coolant used in a pressurized water reactor?
A. Air
B. Liquid sodium
C. Light water
D. Helium gas
C. Light water
Light water serves as both coolant and moderator in pressurized
water reactors used by the Navy.
6. What is the main purpose of the reactor coolant system?
A. Store nuclear waste
B. Transfer heat from the core to steam generators
C. Control radiation exposure externally
D. Produce electricity directly
, B. Transfer heat from the core to steam generators
The coolant system removes heat from the reactor core and transfers
it to steam generators for power production.
7. What type of radiation is most penetrating and requires heavy
shielding?
A. Alpha
B. Beta
C. Gamma
D. Neutron
C. Gamma
Gamma radiation has high penetration power and requires dense
shielding such as lead or steel.
8. What is the primary hazard of neutron radiation in a reactor
environment?
A. Skin burns
B. Activation of materials
C. Hearing damage
D. Chemical poisoning
B. Activation of materials
Neutron radiation can make surrounding materials radioactive
through neutron activation.
9. What term describes the minimum mass needed to sustain a chain
reaction?
A. Fusion mass
B. Critical mass
C. Decay mass
D. Thermal mass
B. Critical mass
(Navy) Exam Practice Questions And
Correct Answers (Verified Answers) Plus
Rationale 2026 Q&A| Instant Download
1. Which type of nuclear reaction primarily powers a naval pressurized
water reactor?
A. Chemical combustion
B. Nuclear fission
C. Nuclear fusion
D. Radioactive decay
B. Nuclear fission
Nuclear fission is the process in which heavy atomic nuclei split into
lighter nuclei, releasing large amounts of energy used in naval
reactors.
2. What is the primary role of the moderator in a nuclear reactor?
A. Absorb all neutrons
B. Increase neutron speed
C. Slow down neutrons to sustain chain reaction
D. Produce fuel rods
C. Slow down neutrons to sustain chain reaction
The moderator reduces neutron energy, increasing the likelihood of
further fission events in fissile material.
,3. Which material is most commonly used as fuel in naval reactors?
A. Uranium-235
B. Carbon-12
C. Thorium-232
D. Lead-208
A. Uranium-235
Uranium-235 is a fissile isotope widely used in naval nuclear
propulsion due to its ability to sustain a controlled chain reaction.
4. What is the function of control rods in a reactor core?
A. Increase reactor temperature
B. Absorb excess neutrons to control reaction rate
C. Cool the reactor coolant
D. Generate steam directly
B. Absorb excess neutrons to control reaction rate
Control rods regulate reactor power by absorbing neutrons and
thereby controlling the fission rate.
5. What is the primary coolant used in a pressurized water reactor?
A. Air
B. Liquid sodium
C. Light water
D. Helium gas
C. Light water
Light water serves as both coolant and moderator in pressurized
water reactors used by the Navy.
6. What is the main purpose of the reactor coolant system?
A. Store nuclear waste
B. Transfer heat from the core to steam generators
C. Control radiation exposure externally
D. Produce electricity directly
, B. Transfer heat from the core to steam generators
The coolant system removes heat from the reactor core and transfers
it to steam generators for power production.
7. What type of radiation is most penetrating and requires heavy
shielding?
A. Alpha
B. Beta
C. Gamma
D. Neutron
C. Gamma
Gamma radiation has high penetration power and requires dense
shielding such as lead or steel.
8. What is the primary hazard of neutron radiation in a reactor
environment?
A. Skin burns
B. Activation of materials
C. Hearing damage
D. Chemical poisoning
B. Activation of materials
Neutron radiation can make surrounding materials radioactive
through neutron activation.
9. What term describes the minimum mass needed to sustain a chain
reaction?
A. Fusion mass
B. Critical mass
C. Decay mass
D. Thermal mass
B. Critical mass
