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ME 417 Quiz 2
| Question | Answer |
|---|---|
| Who discovered X-rays? | Wilhelm Röntgen |
| Who discovered radioactivity? | Henri Becquerel |
| Who helped explain radioactivity and X-rays? | Marie Curie |
| Who discovered uranium? | Martin Klaproth (1789) |
| What is uranium primarily used for in nuclear energy? | As a fuel for nuclear fission reactions |
| What does the curve of binding energy represent? | The energy required to hold a nucleus together as a function of mass number |
| Why does fusion release energy for light nuclei? | Because combining them moves them toward higher binding energy per nucleon |
| Why does fission release energy for heavy nuclei? | Because splitting them moves them toward higher binding energy per nucleon |
| Who discovered nuclear fission? | Lise Meitner (1939) |
| What famous equation relates mass and energy? | E=mc^2 |
| Who led the Manhattan Project? | J. Robert Oppenheimer |
| Who was instrumental in early nuclear reactor development? | Enrico Fermi |
| What was the first nuclear fission reactor? | Chicago Pile-1 (1942) |
| What was the first commercial nuclear power plant? | Shippingport Power Station (1957) |
| What is the purpose of control rods in a nuclear reactor? | To absorb neutrons and control the fission rate |
| Name two common control rod materials. | Boron and Hafnium |
| What reactor type was used at Chernobyl Unit 4? | RBMK reactor |
| T/F: Nuclear fusion involves splitting heavy nuclei. | False (that is fission) |
| T/F: Nuclear fission releases energy by splitting heavy atoms. | True |
| T/F: Uranium was discovered after radioactivity. | False (uranium was discovered first) |
| T/F: Einstein’s work directly influenced nuclear weapons development. | True |
| T/F: Control rods increase the rate of nuclear reactions. | False (they decrease/control it) |
| T/F: Chicago Pile-1 was built for commercial power generation. | False (it was experimental) |
| T/F: The binding energy curve explains why both fusion and fission can release energy. | True |
| T/F: Chernobyl, Three Mile Island, and Fukushima were all nuclear accidents. | True |
| The first commercial nuclear power plant began operation in __________. | 1957 |
| The 1986 nuclear disaster occurred at __________. | Chernobyl |
| The reactor involved in the 2011 nuclear disaster was __________. | Fukushima Daiichi |
| Why does nuclear energy release energy? | reference the curve of binding energy and movement toward higher binding energy per nucleon. |
| what is the process of nuclear fission? | absorption of a neutron into an atomic nucleus, causing it to split into smaller nuclei |
| Curve of Binding E: what process releases more E? | nuclear fusion with small nuclei |
| nuclear power generation is most useful to provide what? | base power |
| On the curve of binding energy, where is the binding energy per nucleon the highest? | Around iron (mid-mass nuclei) |
| According to the binding energy curve, why does fusion release energy? | Light nuclei move up the curve toward higher binding energy per nucleon |
| According to the binding energy curve, why does fission release energy? | Heavy nuclei move down the curve toward higher binding energy per nucleon |
| T/F: Energy is released when nuclear reactions move nuclei toward lower binding energy per nucleon. | False |
| On the binding energy curve, nuclei lighter than iron release energy through __________. | Fusion |
| On the binding energy curve, nuclei heavier than iron release energy through __________. | Fission |
| What happens energetically when protons or neutrons are added to light nuclei? | Energy is released |
| What happens energetically when protons or neutrons are removed from heavy nuclei? | Energy is released |
| T/F: Removing nucleons from light nuclei generally releases energy. | False |
| What major nuclear discovery occurs around 1939 on the timeline? | Nuclear fission |
| The discovery of fission occurs shortly before intense efforts toward __________. | Nuclear weapons |
| What trend is shown in the figure displaying the number of nuclear power plants over time? | Rapid growth in the mid–20th century followed by leveling off |
| Approximately how many nuclear power plants are shown at the peak in the figure? | About 112 |
| T/F: The number of nuclear power plants in the U.S. is steadily increasing today. | False |
| Based on the reactor diagram, what is the purpose of control rods? | To absorb neutrons and regulate the chain reaction |
| The absence or improper operation of __________ contributed to reactor instability. | Control rods |
| T/F: Control rod materials are chosen because they strongly absorb neutrons. | True |
| Which nuclear accident is shown to have occurred in 1979? | Three Mile Island |
| Which nuclear accident occurred in 1986? | Chernobyl |
| Which nuclear accident occurred in 2011? | Fukushima Daiichi |
| in the fission diagram what cause U-235 to become U-236? | absorption of an incoming neutron |
| what are the main products shown after U-236 fissions? | two fission fragments, multiple neutrons, and gamma radiation |
| why are additional neutrons important in the fission diagram? | they can trigger further fission events (chain reaction) |
| approximately how fast does a fission event occur according to the figure? | 10^-7 seconds |
| T/F: the gamma radiation shown carries away part of the released energy | true |
| which type of radiation is stopped by paper or skin according to the figure? | alpha particles |
| which radiation travels farther and can be stopped by aluminum foil? | beta particles |
| which radiation is most penetrating and requires thick shielding? | gamma rays |
| based on the figure which radiation poses the greatest external hazard? | gamma radiation |
| alpha radiation is primarily a health concern when _____________. | ingested or inhaled |
| what does a nuclear cross section represent physically? | a statistical probability of a specific nuclear interaction |
| what does the absorption cross section sigma (a) describe? | the likelihood that a neutron is absorbed (fission or capture) |
| what does the fission cross section sigma (f) describe? | the likelihood that absorption results in fission |
| in the diagram which interaction has the largest "target area" for U-235? | fission (largest cross section shwon) |
| T/F: a larger cross section means a higher probability of interaction. | true |
| what does the burn up rate (BR) represent in the diagram? | fuel consumed due to fission only |
| what does the consumption rate (CR) represent? | fuel consumed due to total absorption (fission + non-fission) |
| why is CR always greater than BR? | because not all neutron absorptions cause fission |
| rates scale with the ________ of the interaction shown in the diagram | probability |
| how much energy is released per used U-235 fission event? | 207 MeV (=3.31E-11 J) |
| what is the molar mass of U-235 | 235 g/mol |
| what unit is used for nuclear cross sections? | barns (1 barn = 10^-28 m^2) |
| which is larger for U-235: sigma (a) or sigma (f)? | absorption cross section sigma (a) |
| what equation gives the fission rate (FR)? | FR = P/ER |
| how is burn up rate (BR) calculated from fission rate? | BR = FR * MW/N(A) |
| how is consumption rate (CR) related to BR? | CR = BR * sigma (a) / sigma (f) |
| why does the equation for CR include cross sections? | because fuel loss depends on interaction probabilities |
| what is the function of the fuel pellets shown in the assembly? | contain fissile material for energy generation |
| where are control rods positioned relative to fuel rods in the diagram? | between fuel assemblies |
| what is the purpose of spacers in the assembly? | maintain geometry and coolant flow paths |
| why are boron and hafnium used as control rod materials? | they have high neutron absorption cross sections |
| why is boron effective for neutron control? | it absorbs neutrons without causing fission |
| what does "thermal neutron mean" | its a neutron that has been slowed down to thermal equilibrium with its surroundings |
| for a thermal neutron its kinetic energy is determined by what? | the temperature of the medium it is in |
| thermal neutrons have ________ kinetic energys | low |
| thermal neutrons speed corresponds to what? | the random thermal motion of atoms in the material |
| thermal neutrons are produced when fast neutrons from fission do what? | collide repeatedly with moderator atoms (like water) losing energy each time |
| U-235 has a very high fission cross section for ______________ ___________, which is why reactors slow neutrons down instead of keeping them fast | thermal neutrons |
| pressurized water reactor: | prevent boiling 65% of plants in the U.S. |
| boiling water reactor: | steam produced directly in reactor |
| for pressurized water reactor the coolant is: | pressurized |
| for pressurized water reactor what is the working fluid | water |
| for boiling water reactor the coolant is: | not pressurized |
| what is the process for pressurized water reactor? | electric generator --> turbine --> steam line --> steam generator --> (pressure tank) / (control rods) / (water pump) --> water pump --> condenser --> cooling tower |
| what is the process for boiling water reactor? | electric generator --> turbine --> steam line --> reactor pressure vessel --> control rod --> water pump --> condenser --> cooling tower |
| what is the biggest con for nuclear energy? | natural disasters |
| why does nuclear use vary state to state? | water sources : regulations |
| who was the top nuclear production in 2019? | U.S. |
| who was the top nuclear share % in 2019? | France |
| for a control rods, what do they sit in? | reactor pressure vessel |
| what leaves a control rod system? | coolant |
| what does the core of control rod system contain? | fuel pellets |
| in the control rods what occurs? | absorption (no fission) |
| in the core of the control rod system what occurs? | absorption + fission & BR - sigma (f) |
| what is the sum of that absorption and absorption + fission | consumption rate (CR) - sigma (a) |
Created by:
mccurdyo