1 Indicate whether the following statements are TRUE or FALSE: 3.1.1 In a nuclear reactor core, inserting control rods deeper accelerates fission. 3.1.2 In a pressurised water reactor, graphite or xen

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QUESTION 3

3.1 Indicate whether the following statements are TRUE or FALSE:

3.1.1 In a nuclear reactor core, inserting control rods deeper accelerates fission.

• False. Control rods absorb neutrons. Inserting them deeper reduces the number of neutrons available for fission, thus decelerating the reaction.

3.1.2 In a pressurised water reactor, graphite or xenon is used as a moderator.

• False. In a Pressurised Water Reactor (PWR), water (specifically light water) is used as the moderator. Graphite is used in other reactor types, and xenon-135 is a fission product that acts as a neutron absorber (poison), not