Optimization of a Seed and Blanket Thorium-uranium Fuel Cycle for Pressurized Water Reactors PDF Download
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Author: Dean Wang Publisher: ISBN: Category : Languages : en Pages : 252
Book Description
(Cont.) Fuel performance was analyzed using FRAPCON. The radioactivity and decay heat from the spent seed and blanket fuel were studied using MIT's MCODE (which couples MCNP and ORIGEN) to do depletion calculations, and ORIGEN to analyze the spent fuel characteristics after discharge. The analyses show that the WASB core can satisfy the requirements of fuel cycle length and safety margins of conventional PWRs. The coefficients of reactivity are comparable to currently operating PWRs. However, the reduction in effective delayed neutron fraction (eff) requires careful review of the control systems because of its importance to short term power transients. Whole core analyses show that the total control rod worth of the WASB core is about 1/3 less than those of a typical PWR for a standard arrangement of Ag-In-Cd control rods in the core. The use of enriched boron in the control rods can effectively improve the control rod worth. The control rods have higher worth in the seed than in the blanket. Therefore, a new loading pattern has been designed so that almost all the control rods will be located in seed assemblies. However, the new pattern requires a redesign of the vessel head of the reactor, which is an added cost in case of retrofitting in existing PWRs. Though the WASB core has high power peaking factors, acceptable MDNBR in the core can be achieved under conservative assumptions by using grids with large local pressure loss coefficient in the blanket. However, the core pressure drop will increase by 70% ...
Author: Dean Wang Publisher: ISBN: Category : Languages : en Pages : 252
Book Description
(Cont.) Fuel performance was analyzed using FRAPCON. The radioactivity and decay heat from the spent seed and blanket fuel were studied using MIT's MCODE (which couples MCNP and ORIGEN) to do depletion calculations, and ORIGEN to analyze the spent fuel characteristics after discharge. The analyses show that the WASB core can satisfy the requirements of fuel cycle length and safety margins of conventional PWRs. The coefficients of reactivity are comparable to currently operating PWRs. However, the reduction in effective delayed neutron fraction (eff) requires careful review of the control systems because of its importance to short term power transients. Whole core analyses show that the total control rod worth of the WASB core is about 1/3 less than those of a typical PWR for a standard arrangement of Ag-In-Cd control rods in the core. The use of enriched boron in the control rods can effectively improve the control rod worth. The control rods have higher worth in the seed than in the blanket. Therefore, a new loading pattern has been designed so that almost all the control rods will be located in seed assemblies. However, the new pattern requires a redesign of the vessel head of the reactor, which is an added cost in case of retrofitting in existing PWRs. Though the WASB core has high power peaking factors, acceptable MDNBR in the core can be achieved under conservative assumptions by using grids with large local pressure loss coefficient in the blanket. However, the core pressure drop will increase by 70% ...
Author: Fouad Sabry Publisher: One Billion Knowledgeable ISBN: Category : Science Languages : en Pages : 530
Book Description
What Is Thorium Fuel Cycle The fertile material in the thorium fuel cycle is an isotope of thorium called 232Th, and the thorium fuel cycle itself is a kind of nuclear fuel cycle. Within the reactor, 232Th is converted into the fissile artificial uranium isotope 233U, which is then used as the fuel for the nuclear reactor. Natural thorium, in contrast to natural uranium, only contains minute quantities of fissile material, which is insufficient to kick off a nuclear chain reaction. In order to kickstart the fuel cycle, either more fissile material or an other neutron source is required. 233U is created when 232Th, which is powered by thorium, absorbs neutrons in a reactor. This is analogous to the process that occurs in uranium breeder reactors, in which fertile 238U is subjected to neutron absorption in order to produce fissile 239Pu. The produced 233U either fissions in situ or is chemically removed from the old nuclear fuel and converted into new nuclear fuel, depending on the architecture of the reactor and the fuel cycle. Fissioning in situ is the more efficient method. How You Will Benefit (I) Insights, and validations about the following topics: Chapter 1: Thorium fuel cycle Chapter 2: Nuclear reactor Chapter 3: Radioactive waste Chapter 4: Fissile material Chapter 5: Nuclear fuel cycle Chapter 6: MOX fuel Chapter 7: Breeder reactor Chapter 8: Uranium-238 Chapter 9: Energy amplifier Chapter 10: Subcritical reactor Chapter 11: Integral fast reactor Chapter 12: Fertile material Chapter 13: Uranium-233 Chapter 14: Plutonium-239 Chapter 15: Isotopes of uranium Chapter 16: Isotopes of plutonium Chapter 17: Weapons-grade nuclear material Chapter 18: Uranium-236 Chapter 19: Burnup Chapter 20: Liquid fluoride thorium reactor Chapter 21: Nuclear transmutation (II) Answering the public top questions about thorium fuel cycle. (III) Real world examples for the usage of thorium fuel cycle in many fields. (IV) 17 appendices to explain, briefly, 266 emerging technologies in each industry to have 360-degree full understanding of thorium fuel cycle' technologies. Who This Book Is For Professionals, undergraduate and graduate students, enthusiasts, hobbyists, and those who want to go beyond basic knowledge or information for any kind of thorium fuel cycle.
Author: Publisher: ISBN: Category : Languages : en Pages :
Book Description
Two of the major barriers to the expansion of worldwide adoption of nuclear power are related to proliferation potential of the nuclear fuel cycle and issues associated with the final disposal of spent fuel. The Radkowsky Thorium Fuel (RTF) concept proposed by Professor A. Radkowsky offers a partial solution to these problems. The main idea of the concept is the utilization of the seed-blanket unit (SBU) fuel assembly geometry which is a direct replacement for a 'conventional' assembly in either a Russian pressurized water reactor (VVER-1000) or a Western pressurized water reactor (PWR). The seed-blanket fuel assembly consists of a fissile (U) zone, known as seed, and a fertile (Th) zone known as blanket. The separation of fissile and fertile allows separate fuel management schemes for the thorium part of the fuel (a subcritical 'blanket') and the 'driving' part of the core (a supercritical 'seed'). The design objective for the blanket is an efficient generation and in-situ fissioning of the U233 isotope, while the design objective for the seed is to supply neutrons to the blanket in a most economic way, i.e. with minimal investment of natural uranium. The introduction of thorium as a fertile component in the nuclear fuel cycle significantly reduces the quantity of plutonium production and modifies its isotopic composition, reducing the overall proliferation potential of the fuel cycle. Thorium based spent fuel also contains fewer higher actinides, hence reducing the long-term radioactivity of the spent fuel. The analyses show that the RTF core can satisfy the requirements of fuel cycle length, and the safety margins of conventional pressurized water reactors. The coefficients of reactivity are comparable to currently operating VVER's/PWR's. The major feature of the RTF cycle is related to the total amount of spent fuel discharged for each cycle from the reactor core. The fuel management scheme adopted for RTF core designs allows a significant decrease in the amount of discharged spent fuel, for a given energy production, compared with standard VVER/PWR. The total Pu production rate of RTF cycles is only 30 % of standard reactor. In addition, the isotopic compositions of the RTF's and standard reactor grade Pu are markedly different due to the very high burnup accumulated by the RTF spent fuel.
Author: Publisher: ISBN: Category : Languages : en Pages : 146
Book Description
Issues affecting the implementation, public perception and acceptance of nuclear power include: proliferation, radioactive waste, safety, and economics. The thorium cycle directly addresses the proliferation and waste issues, but optimization studies of core design and fuel management are needed to ensure that it fits within acceptable safety and economic margins. Typical pressurized water reactors, although loaded with uranium fuel, produce 225 to 275 kg of plutonium per gigawatt-year of operation. Although the spent fuel is highly radioactive, it nevertheless offers a potential proliferation pathway because the plutonium is relatively easy to separate, amounts to many critical masses, and does not present any significant intrinsic barrier to weapon assembly. Uranium 233, on the other hand, produced by the irradiation of thorium, although it too can be used in weapons, may be ''denatured'' by the addition of natural, depleted or low enriched uranium. Furthermore, it appears that the chemical behavior of thoria or thoria-urania fuel makes it a more stable medium for the geological disposal of the spent fuel. It is therefore particularly well suited for a once-through fuel cycle. The use of thorium as a fertile material in nuclear fuel has been of interest since the dawn of nuclear power technology due to its abundance and to potential neutronic advantages. Early projects include homogeneous mixtures of thorium and uranium oxides in the BORAX-IV, Indian Point I, and Elk River reactors, as well as heterogeneous mixtures in the Shippingport seed-blanket reactor. However these projects were developed under considerably different circumstances than those which prevail at present. The earlier applications preceded the current proscription, for non-proliferation purposes, of the use of uranium enriched to more than 20 w/o in 235U, and has in practice generally prohibited the use of uranium highly enriched in 235U. They were designed when the expected burnup of light water fuel was on the order of 25 MWD/kgU--about half the present day value--and when it was expected that the spent fuel would be recycled to recover its fissile content.
Author: Dean Wang
Author: Dean Wang
Author: Martin Augusto Busse
Author: 
Author: Raymond G. Wymer
Author: Fouad Sabry
Author: International Atomic Energy Agency
Author: Donald W. Kuhn
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Author: Keith Courtnay Garel
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