Light Water Reactors (LWR) are nuclear reactors
2023
Light Water Reactors (LWR) are nuclear reactors
Answer: C. Which use ordinary water as moderator — ConceptLight-water reactors are thermal-neutron reactors that use ordinary (light) water, H2O, as the neutron moderator. The same water is also normally the…
- A.
Which use heavy water as a coolant
- B.
Which use graphite rod as moderator
- C.
Which use ordinary water as moderator
- D.
Which use steam as moderator
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Correct answer: C
Concept
Light-water reactors are thermal-neutron reactors that use ordinary (light) water, H2O, as the neutron moderator.
The same water is also normally the primary coolant: its hydrogen nuclei slow neutrons while the circulating water removes heat.
Application
Among the listed descriptions, using ordinary water as moderator is the defining feature of an LWR. In a pressurized-water reactor the water remains liquid under pressure, whereas in a boiling-water reactor some water boils in the core; liquid light water performs the moderation in both designs.
Contrast
Heavy water (D2O) is associated with heavy-water reactor designs, not the light-water category.
Graphite is a solid carbon moderator used in graphite-moderated reactor families.
Ordinary water (H2O) supplies the light hydrogen nuclei used for moderation in LWRs.
Steam carries thermal energy to a turbine; its low density does not make it the moderator description used to define an LWR.
Cross-check
The reactor-family name identifies the moderating medium: light water means ordinary H2O, while heavy water means D2O. Thus, among the offered statements, LWRs are reactors that use ordinary water as moderator.