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Identify the INCORRECT statement regarding a nuclear power plant.
The fuel rods contain pellets of uranium.
Graphite and Boron carbides are used as control rods.
The ordinary water is used as a moderator only after it is enriched with uranium.
Heavy water can be used as a coolant.
Graphite and Boron carbides are used as control rods.
The statement identifying Graphite and Boron carbides as control rods is incorrect because they serve distinct roles. Control rods are specifically used to absorb neutrons and regulate the fission chain reaction, while graphite is primarily used as a moderator to slow down fast neutrons.
The statement identifying Graphite and Boron carbides as control rods is incorrect because they serve distinct roles. Control rods are specifically used to absorb neutrons and regulate the fission chain reaction, while graphite is primarily used as a moderator to slow down fast neutrons.
╧ГaтАЛ├Ч╧ХтИЭdtdNтАЛ тАФ relationship between neutron absorption cross-section and reaction rate
In a nuclear reactor, control rods are composed of high neutron-absorption cross-section materials like Boron, Cadmium, or Hafnium. When inserted into the core, they capture neutrons, thereby reducing the neutron population and slowing or stopping the fission reaction. Moderators like Graphite, Light water (H2тАЛO), or Heavy water (D2тАЛO) are used to thermalize fast neutrons via elastic scattering.
Control rods control the reaction rate by absorbing neutrons.
Moderators slow down neutrons to the thermal energy range.
Graphite is a classic moderator material.
Boron carbide is a classic control rod material.
High energy density compared to fossil fuels.
Low greenhouse gas emissions during operation.
High initial capital investment.
Complex radioactive waste management and disposal.
Base load power generation.
Nuclear propulsion for marine vessels.
Option B is incorrect as it conflates the moderator (graphite) with the control rod material (boron carbide).
Option C refers to PWR/BWR systems where water acts as both coolant and moderator; enrichment is a separate process related to increasing the U235 isotope concentration.
Heavy water (D2тАЛO) is an excellent moderator and coolant in CANDU type reactors.
B is correct тАФ Graphite is primarily a moderator, whereas Boron carbide is used as a control rod material; they are not the same functional component.
Remember that moderators slow neutrons down, while control rods absorb them; mixing these up is a common trap in nuclear engineering exams.
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