Knowledge: K1.07 [2.5/2.8] Topic: Control Rods Assembled . B. the fully inserted control rod is an axially uniform poison. C. fuel temperature increases, decreasing neutron absorption in fuel. B. Axial power distribution and shutdown margin control rod structure, as it is a brittle, salt-like material. To understand the meaning of capacitance and ways of calculating capacitance when a pair of conducting objects carry opposite charges of magnitude $q$, an electric field exists between the conductors, and the potential difference between the objects, $V$, is proportional to $q$. The unused steam is then condensed back to water and reused in the heating process. They consist of a container filled with a strongly neutron-absorbing medium such as boron, cadmium, gadolinium, or hafnium. A. Workers shut down the reactor's power-regulating system and its emergency safety systems, and they withdrew most of the control rods from its core while allowing the reactor to continue running at 7 percent power. C. core delta-T and power density (kW/foot) A nuclear reactor is a device that initiates, moderates, and controls the output of a nuclear chain reaction. A. Moreover, 10B is the principal source of radioactive tritium in the primary circuit of all PWRs (which use boric acid as a chemical shim) because reactions with neutrons can rarely lead to the formation of radioactive tritium via: 10B(n,2x alpha)3H threshold reaction (~1.2 MeV). Control rods are inserted a short distance. QID: P755 (B756)Add Flag fully inserting the rods [2]. Which one of the following will cause group differential control rod worth to become less negative? B. less negative due to shorter neutron migration length. In BWRs, due to the necessity of a steam dryer above the core, this design requires insertion of the control rods from beneath. be used as a control rod material without combination with other metals
Their compositions include chemical elements such as boron, cadmium, silver, hafnium, or indium, that are capable of absorbing many neutrons without themselves decaying. This is because nitrogen has a larger absorption cross-section for neutrons than carbon or oxygen; hence, the core then becomes less reactive. Control blades operate on the same principle as control rods. Their prompt action and prompt response to the reactor are indispensable. The chain reaction can take place only in the proper multiplication environment and only under proper conditions.Suppose one neutron causes two further fissions. C. above; at A. Axial power distribution only D. The moderator temperature coefficient of reactivity is adding more negative reactivity in the upper half of the core. A notable exception to this fail-safe mode of operation is the BWR, which requires hydraulic insertion in the event of an emergency shut-down, using water from a special tank under high pressure. -0.02 %K/K/inch C. 10 75% 20 steps or 18 ppm of boric acid within 10 minutes 85% next 20 steps or 18 ppm within 10 minutes 95% final 10 steps or 9 ppm within 5 minutes 100%. To increase power output, some control rods are pulled out a small distance for a while. Cadmium C-113 has a highly energy dependent cross section in
D. To increase control rod worth by peaking the thermal neutron flux at the top of the reactor core, A. Topic: Control Rods . If you want to get in touch with us, please do not hesitate to contact us via e-mail: [emailprotected], Let assume that the reactor is critical at. How is the speed of reaction in a nuclear reactor controlled? A)In a nuclear power plant, electricity is collected directly from electrons splitting off from fuel atoms. Control rods often stand vertically within the core. With a nuclear power plant operating normally at full power, a 5F decrease in moderator temperature will cause the differential control rod worth to become Topic: Control Rods Past pulmonary function tests were abnormal. A coolant fluid enters the core at low temperature and exits at a higher temperature after collecting the fission energy. A. adversely affect core power distribution. dynamics. Recall that a nuclear reactor generates heat. Control rod position: 110 inches QID: P1456Add Flag may either use the evaporation of water to remove process heat and cool the working fluid to near the wet-bulb air temperature. Also,
Topic: Control Rods (Assume the core average thermal neutron flux is constant.) A. D. increase exponentially until the operator inserts the control rod. A dropped rod causes a smaller change in radial power distribution. Such an arrangement is called a capacitor. Topic: Control Rods influenced by a huge number of factors [2]. Question 54 of 56 Control
D. Radial power distribution and shutdown margin, QID: P1755 (B1855)Add Flag A dropped rod causes a smaller change in axial power distribution. B. increase temporarily, then decrease and stabilize at the original value. On the other hand production of helium may lead to a significant increase in pressure (under rod cladding) when used as the absorbing material in control rods. QID: P354Add Flag Immediately after the operator stops inserting the control rods, the SUR will become ___________; and the core neutron flux level will ___________. Such alloys are designated as Hafaloy, Hafaloy-M, Hafaloy-N, and Hafaloy-NM. Control rod tip thermal neutron flux = 5.0 x 1012 n/cm2-sec Too many . During the normal operation of the reactor, the thermal power from fission dominates. shutdown and start up). Differential boron worth: -0.01 %K/K/ppm design (i.e. During long-term full power operation, fuel temperature decreases as the fuel pellets come into contact with the fuel clad. The fuel rods get hot because of the nuclear reaction. Dropping a center control rod causes a smaller change in shutdown margin. fundamental process by which nuclear reactors produce usable energy. D. Departure from nucleate boiling ratio is within design limits. In PWRs, the shutdown and control rods operability (i.e., trip ability) is an initial assumption in all safety analyses that assume rod insertion upon reactor trip. B. D. decreased moderator density increases neutron migration length. Knowledge: K1.09 [2.5/2.6] RCS average temperature: 575F 113Cd has a specific absorption cross-section. As we have seen, when the rotor spins, electricity comes out of the stator. \text{Leone Le, Drawing September 30 balance} & 4,500.00\\ Topic: Control Rods Which one of the following is a reason for neutron flux shaping in a nuclear reactor core? A. stabilize in the source range. Topic: Control Rods Which statement best describes the function of control rods? Assuming that the main turbine-generator load remains constant, actual reactor power will decrease and then C. increase due to decreased resonance absorption of neutrons. A. By absorbing neutrons, a control rod prevents the neutrons from causing further fissions. Other means of controlling reactivity include (for PWR) a soluble neutron absorber (boric acid) added to the reactor coolant, allowing the complete extraction of the control rods during stationary power operation, ensuring an even power and flux distribution over the entire core. Control rods are an important safety system of nuclear reactors. Using the balances of the general ledger capital and drawing accounts from the work sheet, prepare an owners' equity statement for Northern Lights. B. This negative reactivity causes reactor power to decrease. concisely summarized by the effective multiplication factor,
Absorber boron carbideSource: www.gidropress.podolsk.ru/files/proceedings/mntk2011/documents/mntk2011-108.pdf. preventing it from accelerating beyond control. Joule Most of the world's nuclear reactors are of the _____________ type. This means that in the event of power failure, or if manually invoked due to failure of the lifting machinery, the control rods fall automatically, under gravity, all the way into the pile to stop the reaction. In response to the control rod withdrawal, reactor power will increase A. What structural features differ among the aminoacids? That heat is used to boil water, and the steam from that boiling water is used to spin the rotor. As the neutron energy increases, the neutron cross section of most isotopes decreases. With more than 440 commercial reactors worldwide, including 92 in the United States, nuclear power continues to be one of the largest sources of reliable carbon-free electricity available. \text{Net Income for the month ended September 30} & \$58,800.00\\ D. Both upper and lower core values increase. B. less negative due to shorter neutron migration length. 1) You may use almost everything for non-commercial and educational use. The neutron-absorbing materials used in ATCR should have a sufficiently high melting point and high eutectic temperature with cladding to prevent CR breakage from extensive fuel rod failure in a severe accident, thus avoiding uncontrollable recriticality even if coolant without boron is injected for emergency cooling of the core. 1), although the basic outline is
Topic: Control Rods Question. The mechanical properties of boron in its elementary form are unsuitable, and therefore alloys or compounds have to be used instead. achieved. D. negative; decrease linearly. QID: P454Add Flag Using the appropriate statistical table, what is the approximate ppp-value for this test? The cross-sections of most other elements become very small at high energies, as in the case of cadmium. All other
The 100 percent reactor power conditions are as follows: A reactor startup is in progress from a cold shutdown condition. B)Nearly all nuclear power plants worldwide are built far from water sources to prevent contamination. D. above; above. A. more; more negative and then less negative B. If the control rod is slightly withdrawn such that the control rod tip is located in a thermal neutron flux of 1 x 10^13 n/cm2-sec, then the differential control rod worth will increase by a factor of _______. The most likely disaster in a nuclear power plant is that. Control energy production in a nuclear reactor! 3. Control rods are usually used in control rod assemblies (typically 20 rods for a commercial PWR assembly) and inserted into guide tubes within the fuel elements. Assuming reactor power does not change, which one of the following compares the effects of partially inserting (50 percent) a single center control rod to the effects of dropping (full insertion) the same control rod? The heat created by fission turns the water into steam, which spins a turbine to produce carbon-free electricity. D. Decrease reactor coolant system operating pressure by 15 psia. B. increase and stabilize at a new higher level. absorptivity. A control rod is positioned in a nuclear reactor with the following neutron flux parameters: B. increase and stabilize at a new higher level. Topic: Control Rods B. During the reactor startup and up to about 1% of rated power, the reactor kinetics is exponential as in a zero-power reactor. Knowledge: K1.16 [2.8/3.1] The main reason for designing and operating a nuclear reactor with a flattened neutron flux distribution is to Furthermore, several studies on the use of AI techniques for nuclear reactor design optimization as well as operation and maintenance (O&M) are reviewed and discussed. QID: P1955 (B954)Add Flag Passive nuclear safety is a design approach for safety features, implemented in a nuclear reactor, that does not require any active intervention on the part of the operator or electrical/electronic feedback in order to bring the reactor to a safe shutdown state, in the event of a particular type of emergency (usually overheating resulting from a loss of coolant or loss of coolant flow). attribution to the author, for noncommercial purposes only. Knowledge: K1.12 [2.9/3.1] Decrease reactor coolant boron concentration by 10 ppm. The author grants permission
C. less; more negative during the entire withdrawal Fission-produced xenon can be used after waiting for caesium to precipitate, when practically no radioactivity is left. One purpose of using control rod bank/group overlap is to Neutron flux can be measured, and is roughly proportional to reaction rate and power level. A. Somenuclear power plants use load following. D. shutdown margin and core delta-T, A. power density (kW/foot) and departure from nucleate boiling ratio (DNBR). C. -0.04 %K/K/inch For power reactors, the reactor can behave differently at power conditions due to the presence of reactivity feedbacks. If a control rod is manually withdrawn for 5 seconds, reactor power will These elements have different neutron capture cross sections for neutrons of various energies. In addition, control rods can be used to
C. IRW is the sum of the DRWs between the initial and final control rod positions. They can respond very quickly to the grid requirements. 10) If the purpose of a nuclear reactor in a power plant is to produce energy, why are there control rods? Which one of the following expresses the relationship between differential rod worth (DRW) and integral rod worth (IRW)? Given the following reactivity coefficient/worth values, and neglecting fission product poison reactivity changes, what is the differential control rod worth? Most of the world's nuclear reactors are of the _____________ type. Typically a reactor is equipped with three types of rods for different purposes: (1) safety rods for starting up and shutting down the reactor, (2) regulating rods for adjusting the reactor's power rate, and (3) shim rods for breeder reactor Table of Contents Home Technology Industry breeder reactor Cite External Websites Practicce chemistry question. two common forms: cluster and cruciform. What is a nuclear reactor control rod? Practices, and Prospects (Springer, 2004). Control rod insertion limits ensure that control rods will be more withdrawn as reactor power ____________ to compensate for the change in ____________. Assuming reactor power does not change, which one of the following compares the effects of dropping (full insertion) a single center control rod to the effects of partially inserting (50 percent) the same control rod? Knowledge: K1.04 [3.5/3.5] A. increase due to longer neutron migration length. Therefore cadmium is widely used to absorb thermal neutrons in thermal neutron filters. These control rods are called grey control rods. mechanically suitable rods with B-10 or Boron Carbide (B4C)
Topic: Control Rods They may be reduced by using an element such as hafnium, a "non-burnable poison" which captures multiple neutrons before losing effectiveness, or by not using neutron absorbers for trimming. Identify then label each of the major parts of the nuclear power plant below using the words in the following word bank. C. Ensures that all rods remain within the allowable tolerance between their individual position indicators and their group counters, and ensures rod insertion limits are not exceeded. A nuclear reactor is critical at 50 percent power. Topic: Control Rods [1] C. Elanchezhian, L. Saravanakumar and B. Vijaya
Control rods: Devices to absorb neutrons so that the chain reaction in a reactor core may be slowed or stopped by inserting them further, or accelerated by withdrawing them. Control rods usually constitute cluster control rod assemblies (PWR) inserted into guide thimbles within a nuclear fuel assembly. B. temporarily, then return to the original value due to the resulting decrease in moderator temperature. The adjustment of neutron flux or power level in the reactor is achieved by movement of the control rods. Control rods are used in nuclear reactors to control the fission rate of uranium and plutonium. 2) What is the main job of a moderator in nuclear reactors? Those tubes heat a separate water source to create steam. NetIncomeforthemonthendedSeptember30LeoneLe,CapitalSeptember1balanceWheatoniaMakebu,CapitalSeptember1balanceLeoneLe,DrawingSeptember30balanceWheatoniaMakebu,DrawingSeptember30balance$58,800.0035,000.0028,000.004,500.002,600.00. Knowledge: K1.06 [2.6/2.9] A. provide a more uniform axial power distribution and to provide a more uniform differential rod worth. A partially inserted rod causes a smaller change in radial power distribution. Positive reactivity must be continuously inserted (via control rods or chemical shim) to keep the power to be increasing. Flashcards Learn Test Match Created by mnad60 Terms in this set (51) 1. B. A. [2], The material choice is influenced by the neutron energy in the reactor, their resistance to neutron-induced swelling, and the required mechanical and lifespan properties. fuel rods, are attached on one end by a metal bracket (called a
Topic: Control Rods Will continue to monitor for shortness of breath. B. and stabilize at a value slightly below the POAH. C. temporarily, then stabilize at the original value. A. adversely affect core power distribution. which is crucial for both keeping the fission chain reaction active and
QID: P856Add Flag Boron's mechanical properties are less than desirable for building a
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control rods in a nuclear reactor are used to quizlet