Block 4 Nuclear Science Practice Exam

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• Which material is particularly effective for shielding fast neutrons?
• In reactor kinetics, which term describes a state where the chain reaction dies out because k<1?
• In ore processing, leaching results in uranium being present in which state?
• What does the endpoint energy in beta decay refer to?
• US and UK naval reactors are fueled by uranium enriched to about 93% U-235. What grade is this?
• Which type of decay is used in PET imaging?
• What does the mass defect Δm represent?
• Which reactor is widely used for power production and uses ordinary water as both coolant and moderator, and runs on enriched uranium?
• Which bomb design uses a gun-type mechanism to shoot one subcritical piece into another?
• Which energy component is the second highest from a detonation (about 35%)?
• Which bomb design uses fission to create extreme heat to cause hydrogen fusion in plasma (thermonuclear/Hydrogen bomb)?
• Which is the Fast-Neutron Reactor that uses no moderator, uses fast neutrons, and generates plutonium from natural uranium?
• What rem range will cause illness but rarely fatal?
• Which reactor type is fast-neutron and expensive, with no moderator?
• What is the most important factor in a nuclear reactor?
• Remaining 15% of energy from detonation as various forms of nuclear radiation corresponds to which term?
• What is the chemical process called to extract uranium from ore by dissolving it?
• Which term best describes the energy release when a heavy nucleus splits into smaller parts?
• How is nuclear binding energy related to the mass defect Δm?
• Nuclear Attenuation is best described as
• Which type of radiation is effectively attenuated by lead shielding?
• Convert 1 curie to becquerels.
• The phase in which uranium resides after leaching is?
• How is the effective dose calculated from organ doses?
• How do control rods influence reactor criticality?
• Which reactor uses heavy water (D2O) as coolant and moderator and does not require enriched uranium but is difficult and expensive?
• Which factors determine the shielding thickness required to attenuate gamma radiation?
• What is the inverse-square law for intensity from a point source?
• Which is the first-generation British reactor that uses CO2 as coolant with water as a secondary and uses natural uranium?
• In reactor physics, which condition describes a reactor that is supercritical due to more than one neutron causing fissions?
• In the described fuel production sequence, which is the second stage?
• Which statement identifies the listed isotopes as common fissionable fuels?
• What is the resulting nucleus called after radioactive decay?
• Which of the following represents beta-minus decay for a nucleus (Z,A)?
• Which shielding material and principle is most effective against gamma radiation?
• Which component is used to control energy rate precisely without stopping and starting?
• Which type of beta decay increases the atomic number Z by 1 while keeping the mass number A constant?
• What protects people and equipment during hazardous incidents?
• A nuclear reaction in which a massive nucleus splits into smaller nuclei with the simultaneous release of energy is called?
• The outcome of leaching uranium from ore is that uranium is dissolved in which phase?
• Leaching in uranium ore processing is an example of which type of operation?
• Which decay decreases the atomic number by 1 and emits a positron?
• Which historical device used a gun-type assembly to combine two subcritical masses by firing one into the other?
• What rem range has a low probability of survival?
• Which term best describes the process of light nuclei fusing to form a heavier nucleus releasing energy?
• Which phenomenon is described as a fireball overtaking the shockwave and becoming visible again?
• Which detector operates by producing light flashes in scintillating material when hit by ionizing radiation?
• Beta-minus decay emits an electron and which accompanying particle?
• Initial radiation is radiation emitted during the early stage after a nuclear detonation.
• What is a typical annual background radiation dose for a person?
• Which reactor type is most popular in the U.S., uses ordinary water as coolant and moderator, and requires enriched uranium?
• How do you compute the Q-value for a nuclear reaction using masses?
• What is a half-value layer in shielding terminology?
• Which neutron energy range is most effective for sustaining fission in U-235 in a thermal reactor?
• ACR is an automated device used for capturing and separating specific gases from the atmosphere. What does ACR stand for?
• The gray (Gy) is a unit that measures which quantity in radiation protection?
• A series of reactions in which a product or by-product of the reaction initiates further reaction is known as what?
• What is the probability of decay of a nucleus per unit time called?
• During enrichment, which term describes the tail?
• What are the two types of neutron radiation?
• Which detector measures radiation quantity by counting hits but cannot distinguish radiation type?
• In gamma shielding, increasing the shielding thickness causes transmitted intensity to
• In shielding terminology, what does the half-value layer quantify?
• What is secular equilibrium in a decay chain?
• Why are short half-life radiopharmaceuticals preferred for diagnostic imaging?
• Which decay transforms a neutron into a proton, increasing the atomic number by 1?
• Which detectors offer higher energy resolution and can characterize both quality and quantity of radiation, but are susceptible to thermal noise and often require cryogenic cooling?
• The statements 'Single event produces 12.9 MeV; Fraction of one fission event; Far more powerful because of fuel density' correspond to which concept?
• Which of the following describes the source of delayed radiation?
• Which detector uses an electric field to collect charge from X-ray, gamma, and particle interactions?
• What is a neutron poison and give two examples?
• What is activation in a nuclear context, and what is a typical consequence for materials?
• Moderators slow neutrons to thermal energies to increase the fission probability of fissile material. What is the direct effect of this on reactor operation?
• If a point source's distance is doubled, by what factor does the intensity change?
• What is the process of shooting a neutron at an atom called?
• The term describing anything containing reactivity or the reactor itself is
• Which energy form is not listed as a primary detonation energy component?
• Which particle is emitted along with the electron in beta-minus decay?
• Which reactor type is graphite moderated and features a channel-type core with pipes called channels?
• An alpha particle is equivalent to which nucleus?
• In gamma-ray shielding, the symbol μ denotes which property of the shielding material?
• Which statement best describes how the neutron cross-section affects shielding design?
• What is the difference between prompt and delayed neutrons in a reactor?
• Which group includes all components needed in a nuclear reactor?
• U-235 and Pu-239 are examples of which category?
• During Beta Minus decay, which change occurs in the nucleus?
• Which expression correctly describes the decay law for activity with time constant λ?
• What is the term for gamma rays that are released and remitted as X-rays after atmospheric interaction (Compton effect)?
• In gamma spectroscopy, what does a peak at a particular energy indicate?
• Which statement about the radiation weighting factor w_R for gamma rays is true?
• Which energy component is the highest in a detonation (about 50%)?
• Which list contains only the top six uranium-producing countries?
• Anything that is containing reactivity or the reactor itself is called the
• Which statement about enrichment categories is accurate?
• Which detector typically uses scintillation light produced by ionizing radiation to measure energy?
• What is the role of a moderator in a nuclear reactor?
• What is the primary role of boron additives in hydrogen-rich neutron shielding?
• Which British reactor is the AGR and uses CO2 as coolant?
• Xenon is commonly described as what in neutron physics?
• What does ALARA stand for in radiation protection?
• How does neutron cross-section influence shielding and reactor design?
• Which event occurs when a positron encounters an electron?
• Which uranium grade is used to fuel US and UK naval reactors at about 93% U-235?
• Which particle is emitted in beta-minus decay along with the electron?
• What are the main classes of civilian radioactive waste?
• Immediately after a fission event, aside from the fragments, what other prompt products are typically emitted?
• The two types of neutron radiation are
• What is the length of time required for half of the radioactive atoms in a sample to decay called?
• Which equation gives the number of undecayed nuclei N_t remaining after time t?
• Why does fusion of light nuclei release energy per nucleon more efficiently than fission of heavy nuclei?
• High enriched uranium is defined as greater than 20 percent U-235. Which option correctly matches this definition?
• Which detector type is suitable for high-resolution gamma spectroscopy due to its energy resolution but requires cooling?
• In the described fuel production sequence, which is the final stage?
• How does a scintillation detector convert radiation to a measurable signal?
• Which component is adjustable and can stop a reaction?
• Which of the following countries are among the top six uranium producers?
• If the distance from a point source is doubled, by what factor does the intensity fall (assuming an inverse-square law)?
• Which is the Advanced Gas-Cooled Reactor that uses CO2 as coolant?
• Which British reactor uses natural uranium and CO2 as coolant with water as a secondary coolant?
• Fires electrons that are picked up by a sensor to create images of very small things. What device is this?
• Which term describes anything containing reactivity or the reactor itself?
• Why are delayed neutrons important for reactor control?
• A dose of 0.5 Gy is measured at 1 m from a source. If the distance is increased to 2 m with no shielding, the new dose is:
• Nuclear Attenuation refers to
• What is the difference between the mass of an atom and the sum of the masses of its protons and neutrons called?
• Which radioactive decay increases the atomic number by 1 while leaving the mass number unchanged by emitting an electron?
• Which statement about unspent fuel and radiation is accurate?
• Which device is used to monitor exposure to radioactive materials and records dose via thermoluminescence?
• Leaching is an example of which type of operation?
• Delayed radiation is caused by decay of which substances?
• What percentage of the world's uranium comes from the six top producers?
• Which of the following radiotracers is commonly used in PET imaging and has a half-life near 110 minutes?
• Uranium enriched to about 3-5% U-235 is called reactor grade uranium. Which option names this correctly?
• Delayed radiation behavior over time is best described as which?
• Cesium-137 is commonly used as what in nuclear instrumentation?
• Which two methods are used to extract uranium?
• Which of the following best describes leaching in uranium ore processing?
• Which type of radiation originates from the nucleus and does not change the atomic number or mass number?
• Which detector offers higher energy resolution and can characterize both the quality and quantity of radiation but typically requires cryogenic cooling?
• The rod used for starting/shutting down the reactor is the
• Which statement about tissue weighting factors w_T is true?
• Which decay transforms a proton into a neutron, decreasing the atomic number by 1?
• Which expression relates half-life T1/2 to decay constant λ?
• In a fission event of a heavy nucleus, where is most of the energy released immediately?
• Which device is primarily used to count radiation events and does not provide energy information?
• Which equation correctly relates the activity A, the decay constant λ, and the number of undecayed nuclei N?
• Which detector is based on ionization in a gas and is used to detect alpha, beta, and gamma radiation but cannot distinguish among them?
• Which decay process releases an alpha particle, causing the atomic number to decrease by 2 and the mass number to decrease by 4?
• A nuclear reaction in which atomic nuclei of low atomic number fuse to form a heavier nucleus with the release of energy is called?
• During Beta Plus decay, which change occurs in the nucleus?
• The control rod that compensates for changes in reactivity is the
• Th-232 and Uranium-238, naturally occurring, are best described as which category?
• Which isotope is a commonly cited fissile material in reactors?
• What is the term for the light emitted by certain materials when struck by ionizing radiation?
• Among alpha, beta, and gamma radiation, which has the highest ionizing power but the least penetrating ability?
• In a scintillation detector, which device is commonly used to convert scintillator light into an electrical signal?
• Which reactor is the Canada deuterium uranium reactor?
• Delayed nuclear radiation arises from the decay of fission fragments after the initial fission event.
• Which shielding material is typically used to attenuate gamma radiation?
• For gamma radiation, how is equivalent dose related to absorbed dose?
• Which reactor type is commonly called CANDU and uses heavy water as both coolant and moderator?
• Which expression gives N_t, the number of undecayed nuclei at time t?
• Unspent nuclear fuel refers to fuel that has not yet undergone fission.
• Which energy component accounts for about 15% of the detonation energy as various forms of radiation?
• Which category best describes Th-232 and Uranium-238 as fertile elements?
• What is the expression for activity after time t given initial activity A0?
• How is the decay constant λ related to a isotope's half-life T1/2?
• Uranium enriched to about 90% U-235 is called weapon grade uranium. Which option names this correctly?
• What device is commonly used to separate U-238 and U-235 during enrichment?
• Which microscope type images nanoscale objects by scanning with an electron beam?
• Refined plutonium over 93% is called which grade?
• Name a commonly used PET radiotracer and its approximate half-life.
• Beta minus decay causes the element to move in which direction on the periodic table?
• What event occurs when k_eff equals 1 in a nuclear reactor?
• Thermal neutron: Fission material will undergo fission when it absorbs a
• What organization is responsible for rules concerning nuclear materials in the United States?
• What describes a fast breeder reactor?
• Which factor can reduce the critical mass of a fissile material?
• Which automated system is designed to clean below-ground water or air?
• If a person receives 200 to 1000 rems, what is the likely outcome?
• Which reactor type produces more Pu-239 than it consumes and uses no moderator?
• Distinguish deterministic effects from stochastic effects of radiation exposure.
• Which of the following is NOT a factor influencing the critical mass of a fissile material?
• Which detonation design uses an implosion method with highly compressed layers?
• What factors influence the critical mass of a fissile material?
• Which statement defines a fissile material?
• Which sector uses leaching to obtain uranium from ore?
• Which component is used to slow down fast neutrons to prevent them from leaving the reactor core?
• What is the approximate enrichment of reactor grade uranium?
• After fission, what are the typical immediate products?
• What dose range in rems can produce some changes in the blood?
• What happens in electron capture?
• Low enriched uranium is defined as having less than 20 percent U-235. Which choice represents that definition?
• Which category do Thorium-232 and Uranium-238 best fit?
• Which process releases more energy per nucleon and why?
• What does a reading on a Geiger–Müller counter represent?
• What does AGFU stand for in systems used for below-ground applications?
• What particle is emitted during alpha decay?
• What is the correct order of fuel production from ore to reactor fuel?
• How do you compute the activity A from N0 and λ at t = 0?
• Convert 1 MeV to joules.
• A sample has N0 = 6.0×10^9 and λ = 1.386×10^−9 s^−1. What is its activity A at t = 0?
• What is specific activity, and how does it differ from activity?
• Which component flows between the fuel rods to remove heat produced by fission and water can also act as a moderator?
• Name two common reactor coolant materials.
• What is the minimum mass of a fissionable isotope that provides the number of neutrons needed to sustain a chain reaction called?
• In the described fuel production sequence, which material is the first stage?