Unit 11 : Random Quiz

Which component of a nuclear power plant converts thermal energy into electrical energy?

Steam turbineModeratorControl rodsCoolant pump

What is a key safety feature of a PWR in the event of overheating?

The pressure vessel bursts to release steamThe containment vessel absorbs neutronsThe control rods are automatically ejectedBoiling of the coolant reduces moderation, lowering the fission rate

What is a disadvantage of BWRs compared to PWRs?

They use graphite moderators, which are less efficientThey require plutonium fuelThey cannot follow electrical load demandsRadioactive steam goes directly to turbines

What challenge arises from the neutron produced in d-t fusion?

It damages the tokamak’s magnetic field coils directlyIt makes magnetic confinement impossibleIt triggers runaway reactionsIts energy must be captured to generate power

What best explains the near-constant mass of one fission fragment around A=139?

It maximizes neutron emission per fissionIt is due to conservation of energy in fissionIt corresponds to magic numbers of protons and neutronsIt matches the neutron-to-proton ratio of uranium

Which reactor type uses steam from the reactor core directly to drive the turbines?

Pressurised heavy water reactor (PHWR)Pressurised water reactor (PWR)Advanced gas-cooled reactor (AGR)Boiling water reactor (BWR)

What is a major advantage of aneutronic fusion reactions?

They use heavier elements which are more abundantThey occur spontaneously in natureThey are more efficient at lower temperaturesThey produce only charged particles, which can be converted to electricity directly

Which fusion strategy aims to achieve long confinement times using magnetic fields?

Inertial confinement fusion (ICF)Magnetic confinement fusion (MCF)Laser heatingElectrostatic focusing

Why are delayed neutrons critical for reactor control?

They release more energy than prompt neutronsThey slow the response time of the chain reaction, enabling controlThey are produced by the moderatorThey reduce the number of prompt neutrons

What distinguishes the net electrical power from the gross electrical power of a reactor?

Gross power includes thermal energyNet power is always higher due to efficiencyNet power includes losses due to radiationNet power subtracts internal plant usage from gross power

Which reactor type uses ordinary water for both moderation and cooling?

Pressurised water reactor (PWR)CANDU reactorAdvanced gas-cooled reactor (AGR)Boiling water reactor (BWR)

What condition defines ignition in a fusion plasma?

The plasma becomes electrically neutralThe plasma converts entirely to heliumThe confinement field is switched offThe plasma maintains its temperature through α-particle heating alone

What is the Lawson criterion used for?

To measure plasma temperature stabilityTo assess fuel efficiency in fission reactorsTo determine the minimum confinement conditions for net energy gain in fusionTo calculate the neutron flux in a reactor

Which component contributes the most to the energy released in a typical fission reaction?

Kinetic energy of the fission fragmentsEnergy carried by prompt gamma raysKinetic energy of the neutronsBeta decay energy from fragments

Why is

^{238}

U not easily fissioned by thermal neutrons?

The neutron cross section is too large

^{238}

U has too many protonsNeutron capture in

^{238}

U results in a compound nucleus with excitation energy below the fission barrier

^{238}

U always decays by alpha emission

Why are fast breeder reactors not widely used commercially?

They produce too much radioactive wasteThey do not utilize uranium fuelThey cannot achieve criticalityThey are expensive and complex to operate safely

Why does fission of heavy elements release energy?

The nucleus absorbs thermal energy before splittingFission creates more protons than neutronsThe fission products have higher binding energy per nucleon than the original nucleusFission breaks quark bonds, releasing energy

What condition makes a nucleus unstable to spontaneous fission in the liquid drop model?

The surface energy term becomes zeroThe number of neutrons is greater than protonsThe nucleus is at absolute zero temperatureThe ratio Z²/A exceeds a critical value

What allowed natural nuclear reactors to operate at Oklo two billion years ago?

Cosmic rays triggered continuous fissionThe uranium was already enriched artificiallyNatural uranium then had a higher proportion of

^{235}

UThe ore contained plutonium

Why is tritium breeding important for fusion power reactors?

Tritium converts gamma rays to electricityTritium does not naturally occur and must be produced for sustained fusionTritium regulates magnetic field geometryTritium cools the plasma

Unit 11 : Random Quiz#