Nuclear Wastes Technologies for Separations and Transmutation (1996) / Chapter Skim
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F TRANSMUTATION CONCEPTS
F TRANSMUTATION CONCEPTS
Pages 201-314
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From page 201... ...
The ALMR project arbitrarily defines breeding ratio as the ratio of the number of atoms of new 239PU and 24iPu formed to the number of atoms of 239Pu and 24tPu consumed by neutron absorption. The definition is arbitrary, because all atoms of plutonium, as well as the minor actinides, fission in a fast spectrum.
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From page 202... ...
The "actinide burner" core contains no radial and internal blanket assemblies to reduce the generation of new 239Pu by neutron absorption in 238U, resulting in a lower breeding ratio. The amount of TRU start-up inventory required depends somewhat on the breeding ratio at which an ALMR is operating.
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From page 203... ...
203 Cal ~ _ _ _ ~_ ~'AS IL C,' _ __ _ Z AIL 0O \\ it.
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From page 205... ...
APPENDIXF- TRANSMUTATIONCONCEPTS FIGURE F-2 Core layout comparison.
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From page 206... ...
However, with decreasing breeding ratio, less negative reactivity is available from Doppler broadening of the neutron absorption resonances that occurs when the filet is heated in a power excursion. Based on these considerations, GE concludes that a TRU burner with a breeding ratio of ~0.60 and a core height of 0.76 m (30 in.)
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From page 207... ...
Transmutation of the considerable quantities of uranium recovered from LWR spent fuel Is not considered. Because TRU transmutation is spoken of popularly as "actinide burning" within reactor programs in this country and abroad, that terminology is occasionally used herein.
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From page 208... ...
The ALMR project does not propose to develop separation processes with decontamination factors sufficiently high that TRU-containing wastes could be disposed of as low-level waste, nor does it propose to transmute fission products present in LWR spent fuel and generated by ALMR operation.5 The Department of Energy's 1991 National Energy Strategy (DOE, 1991) assumed a similar rate of introduction of TRU-burning ALMRs' beginning in 2012 (Goldner et al., 1991)
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From page 209... ...
, commercial-scale facilities to reprocess EWR spent filet would be required. According to the GE ALMR reports, this facility could be an aqueous PUREX/TRUEX process or could be based on ANL's proposal to develop a pyrochernical separation process for EWR spent fuel.
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From page 210... ...
recovery of radioiodine, macaroon, and technetium if EW11 spent fuel is to undergo aqueous reprocessing and processes to produce suitable waste solids from these separated radioelements, and · processes to separate radioactive cesium and strontinn,, and to produce suitable waste forms for these separated radioelements, and processes and facilities for storage of these separated radioelements for 200 to 300 years before disposal as radioactive waste (this is a possible additional separation proposed by ALL [Chang, 1992b] and by DOE [Young, 1991]
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From page 211... ...
composition but without changes in filrl-rod diameter or in the number of fuel rods. The diameter of the reactor vessel would remain constant and is limited by the maximum allowable power density or by the linear heat generation rate of the fuel rods so that safety characteristics are not compromised.
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From page 212... ...
the effect of reducing the breeding ratio to increase consumption rate of TRUs Dom an EWR spent fuel, thereby compromising passive safety features; 2. the effect of more favorable neutronic properties of MAs, such as 237Np, on reactivity transients and reactor safety; 3.
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From page 213... ...
Some ANL flowsheets for pyrochemical processing of LWR spent fuel show that much or all of the long-lived fission product 99Tc would accompany this uranium (McPheeters et al., 19911. Flowsheets developed more recently by the committee and by ANL show that the technetium could be separated and sent to geologic disposal.
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From page 214... ...
it Even when the uranium in LWR spent fuel is disposed of as HEW in a geologic repository, We long-term risks homthe uranium decay daughters is an important environmental issue (Svensk Karnbamlehantering AB, 1992~.
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From page 215... ...
Application of conventional aqueous reprocessing to multiply recycled MOX fuel could increase the necessary cooling time between reactor discharge and reprocessing, further increasing the time to obtain a given reduction in TRU inventory. REACTOR DYNAMICS AND SAFETY PARAMETERS Although fast reactors have been operated with mixed pluton~um-urarnum fuel, there is essentially no operating experience with significant quantities of MAs.
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From page 216... ...
states that i The secure automated fabrication (SAF) line located at Hanford, Washington, was put into operation in the early 1980s to develop MOX fuel for testing in the FFTF as part of the Clinch River liquid-metal reactor project.
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From page 217... ...
217 However, the ALMR program has not yet addressed the recycle and possible transmutation of these troublesome long-lived fission products. STEAM GENERATORS Steam generators have proved to be the most troublesome major component in the pressurized water reactor system.
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From page 218... ...
With regard to the relative economic potential of the ALE, ALMR plants (e.g., PRISM) may be able to compete econom~caDy with water reactors if fuel reprocessing turns out to be technically and economically feasible, and if the overnight capital costs of these plants are as low as the vendors indicate (National Research Council, 19924.
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From page 219... ...
Expected contributors to the higher cost for TRU burning are the likely higher cost for high-ye chemical recovery of actinides and fission products; the expense of additional L`WR reprocessing for reactors with degraded breeding ratio to increase TRU consumption; and the expense of additional development, testing, and safety issues associated with recycle of MAs and fission products. Therefore, the era of competitiveness of the TRU-burning ALMR with the EWR wall be even later than that of economical introduction of ALMRs designed only for power generation.
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From page 220... ...
Plutonium from EWR spent fuel was assumed to provide the fissde matenal for the initial core of the MAR and for the first two reloads. Thereafter, the ALMR was assumed to sustain its own fee} cycle (i.e., unity breeding ratio)
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From page 221... ...
APPENDIXF- TRANSMUTATIONCONCEPTS FIG - E F-3 ALMR introduction analysis. 70 -~ By co E 60 co 55 an 50 m 45- l 401 1 1 1 20 30 40 50 1 1 1 1 1 ~ 90 100 110 120 130 140 150 160 60 70 80 Minimum Pnce, 1992 $/lb U308 ALWR ALMR Q $70~kg ALMR ~ $20~kg ALMR ~ $10~/kg ALMR ~ $35~kg 221
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From page 222... ...
The TRU-bu~ring ALMR reactor and filet cycle are expected to be more expensive than for an ALMR optimized only for power generation (Chang, 1992b; Taylor et al., 1991~. Expected contributors to the higher cost for TRU burning are the likely higher cost for highyield chemical recovery of actin~des and fission products, the expense of additional EWR reprocessing for reactors with degraded breeding ratio to increase TRU consumption, and the expense of additional development, testing, and safety issues associated with recycle of MAs and fission products.
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From page 223... ...
APPENDIXF- TRANSMUTATIONCONCEPTS FIGURE F-4 ALMR introduction analysis (Using ORNL deployment data)
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From page 224... ...
This section discusses an extension of the experience with such pluton~um-uran~um MOX filet in LWRs to the more complex requirements for refabricating and burning MOX fuel that contains radionuclides recovered from reprocessed LWR spent fuel (i.e., plutonium, the MAs, and selected fission products 99Tc and radioiodine)
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From page 225... ...
nuclear industry adapted the PWR and BWR designs for "self-generated uranium-pluton~um recycle" in which the fissile material recovered from reprocessed LWR spent fuel would be recycled back to the same reactors. Figure F-5 shows a representative material flowsheet for a commercial 1,000 MWe PWR based on a design of mid-1970s vintage by Combustion Engineering (Pigford and Yang, ~ 977; Hebe} et al., 19784.
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From page 226... ...
· 3% 23sU 22.3 Mg Light Water Reactor E = 30.4 MW day/kg Fuel Life = 3 yr n = 0.342 L = 0.80 Uranium Recvcle Conve' sion and ~ Isotope 0.83% 235U Separation ~ Separative 18.0 Mg 0.25%23 5U 81W.7°rM9 ~ 105 Mg Fuel Reprocessing / Fission Products 0.912 Mg Depleted Uranium 0.45% 235U 5.49 Mg
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From page 227... ...
Thus, the distribution of neutron flux and the concentration of plutonium in MOX rods are cntical design issues that establish how the two types of filet rods are distributed in the fuel assemblies. In the first arrangement, a MOX fuel rod near normal filet rods, exposed to nearly the same neutron flux, may generate more thermal power.
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From page 228... ...
Thus, the division into plutonium burners and normal EWRs would simplify the issues of controlabsorber design, reactivity control, and local heat generation rate in the MOX filet rods. Such plutonium burners could serve as devices for transmuting the MAs and fission products.
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From page 229... ...
APPENDIX F - TRANSMUTE TION CONCEPTS FIGURE F-6 Material flowsheet for uran~um-pluton~um fi~eled pressurized water reactor. 1 000 Mw C Natural Uranium 0.715% 235u 26.5 Mg Plutonium Fuel I 28.1 Mg Fabrication t t Light Water Reactor E = 30.4 Mw day/kg Fuel Life = 3 yr n = 0.342 L=0.80 Plutonium Recycle Fission C AI Products Fuel Reprocessing I1 ~ l ~ 71°/O Fissile 54.5°/O Fissile Uranium 0.45% 235V 25.5 Mg Source: Pigford and Yang (1977)
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From page 230... ...
,300 $/kWe 1,475 $/kWe 30-year levelized 6.3 cents/kW.h 7.2 cents/kW.h total generation SOURCE: Electnc Power ResearchInstitute(1990~. aThese requirements apply to both the large evolutionary EWRs and to the m~-sized EWRs with passive safety features.
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From page 231... ...
Much of the curium alpha and neutron activity would come from 24 Cm and 244Cm with contributions Dom 246Cm and 248 Cm as these isotopes build up in later fuel cycles of the transmutation period. Further capture of neutrons together with beta decay would produce some 252Cf, which is an intense emitter of neutrons Tom spontaneous fission.
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From page 232... ...
The comparative performance is similar, but time scales are shorter by a factor of about 5 for a declining power scenario In which nuclear power is phased out as rapidly as possible consistent with transmuting the maximum amounts of TRUs and key fission products in the HEW. Facilities and Support Requirements REPROCESSING REQUIREMENTS Transmutation with LWRs requires facilities of high reliability and capacity factor to reprocess the EWR spent fuel.
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From page 233... ...
FUEL FABRICATION REQUIREMENTS In addition to reprocessing capability, one or more facilities would be needed for MOX fuel fabrication, which might be collocated with reprocessing. (The technology is discussed below under State of the Technology.)
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From page 234... ...
A recent design for a much larger MOX fabrication plant is that of the Siemens Mixed Oxide Fuel Fabrication Facility at Hanau, Germany. The specification is for a facility of nominally 120 MgH~Jyr at a cost reported to be about $500 million (Nuclear Fuel, 1992~.
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From page 235... ...
For an aqueous-based process, this would include scale-up and pilot-scale demonstration/test of the TRUEX process. For a pyrometallurgical process for L'WR spent fuels, laboratory-scale development must be completed prior to further scale-up and demonstration/test.
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From page 236... ...
Because of the higher thermal fission cross section for 239Pu, there is a tendency for power peaking at or near the MOX fuel rods. The spatial distribution of neutron flux and of plutonium concentration wall vary considerably during the time (several years)
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From page 237... ...
~7 More recently, DOE funded a major program of MOX fuel development and performance verification to support the development of the Clinch River reactor, emphasizing fuel reliability at high burn-up as a key to an economical fuel system (Leggett and Omberg, 1987~. The overall experience with ceramic, metal, cermet, and MOX fuels illustrates the need for stringent quality control and underscores the exacting nature and significant cost of the comprehensive fuels development, testing, and performance verification that is required for licensing, not only for EWRs but for any transmutation system.
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From page 238... ...
If major new test facilities are required, the additional time to design, approve, Find, and construct them could easily double the estimate of a decade. An extended period of fuel development, in-reactor test, and demonstration would be needed for the compositions that would occur in the later fuel cycles of the transmutation period.
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From page 239... ...
Finally, one must recognize the safety issues inherent in transportation of the radioactive materials between sites. Cost Information DEVELOPMENT COSTS One development cost of significance is the waste form and process to package the residual HEW for geologic disposal.
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From page 240... ...
20 The reprocessing cost range from Chapter 5, $800 to $1,900/kgHM, assumes aqueous-based technology for the oxide LWR spent fuel. That assessment is based primarily on a significant body of data on commercial reprocessing in several large facilities outside the United States using aqueous-based technology, which gives insight into the costs.
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From page 241... ...
, 3. transmutation of TRUs and more fission products recovered by nonaqueous chloride volatility or the aqueous reprocessing of EWR spent fuel, which uses a molten-salt, graphitemoderated multiplying system that is fueled partly with thorium, and generates electric power and reprocesses the molten fuel salts (Case ATW-3~; 4.
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From page 242... ...
242 TECHNOLOGIES FOR SEPARATIONS AND TRANSMUTATION FIGURE F-7 Reference design for commercial waste transmutes. Proton I Beam Accelerator ' ~ 1 Waste Feed ~ Aqueous Chemical I Separations Stable and Short Lived Products 1 ~ Source: Los Alamo s National Laboratory (1992~.
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From page 243... ...
radiotoxicity of final disposed waste less than that of uranium ore; and 3. reduction of the time scale for nuclear waste storage to that of a human lifetime.
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From page 244... ...
In all cases, the ATWs have even higher reduction factors as a Unction of years of operation. Similarly, the time required to attain a given inventory reduction would be less for any of the ATW concepts than for an ALMR or a EWR.
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From page 245... ...
20 MeV 1 30m 1 Beam Energy Beam Current Beam Power Total RF Power RF to beam efficiency AC to RF efficiency AC power requirement Average CCL gradient Transverse output emittance CCL operative/beam size ratio RFQ Frequency/current CCL Frequency/current CCL length/1 O-cell tank CCL Klystrons Emittance Filter 100m ~1750m AT\/ /-1 1600 MeV 250 ma 400 MW 475 MW 0.84 0.58 845 MW 1 My/m 0.065 ~ cm - m red 11-21 350 MHz, 125 ma 700 MHz, 250 ma 1750/812 480 SOURCE: Los Alamos National Laboratory (1992)
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From page 246... ...
This range of power densities is somewhat higher than that of the FFTF but considerably smaller than that of the High Flux Beam Reactor at Brookhaven National Laboratorv CALL analyses show decay heat generation in the target is manageable, with r -- r- ~o- ~-c~proper heat exchanger designs for rated power operations. A Multiple nuclear reactions involving high energy neutrons in the target produce a host of nuclides7 many of which are radioactive.
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From page 247... ...
, . / AIL X~ BLANKET ASSEMBLY The ATW-1 concept specifies aqueous reprocessing technology to obtain TRUs Dom LWR spent fuel and to process the blanket and target materials.
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From page 248... ...
248 TECHNOLOGIES FOR SEPARATIONS AND TRANSMUTATION t1oURE F-9 Blanket design.
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From page 249... ...
The heavy-water fluid fuel is circulated through an external heat exchanger (where problems with deposits from the saturated slurry-solution fuel working across a hightemperature gradient can be expected) generating steam to drive a turbine generator.
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From page 250... ...
I ~ Disposal :_ Repos. ll ll l 1 l Heat Reiection I · Waste Heat Electrical Power
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From page 251... ...
f 0.083 day for fission product processing. SOURCES: Arthur (1992a, by; Bowman (1992a, by; Davidson (1992~.
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From page 252... ...
The concept specifies aqueous reprocessing technology to obtain TRUs from EWR spent fuel and to process the blanket and target materials. Separated fission products would be formed into solid targets for transmutation in the thermal neutron flux.
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From page 253... ...
1.70 Mg HM 1.70 Mg TRU 1.52 Mg Pu Feed i 73.07 MgHM 73.07 Mg TRU 34.10 Mg Pu Reprocessing 4.55 Mg HM 4.55 Mg TRU 1.01 Mg Pu 1 , 1 Loss 0.07 Mg HM 1 1 Radioactive Waste Repository 253 Blanket and Heat Exchanger 1.6 GeV, 250 mA =0.193, L=0.80 6.61 Mg HM 6.61 Mg TRU 3.02 Mg Pu = 71.45 Mg HM 71.45 Mg TRU 32.65 Mg Pu ~ , r
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From page 254... ...
254 FIGURE F-12 Double active loop. TECHNOLOGIES FOR SEPARATIONS AND TRANSMUTATION , -- ~ Np, Pu Loop LWP Actinide Feed 15 Day Residence Time Transmuter 90 Day Residence Time Am, Cm Loop 1 SOURCE: Los Alamos National Laboratory (1992~.
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From page 255... ...
Americium, curium, and fission products are separated in the processing unit of the neptunium/plutonium loop and are diverted abler holding for 90 days to a separate "americium/curium loop." Amer~cium/cur~um slurry produced in that loop is circulated through a separate portion of the reactor for irradiation and transmutation and then through another external heat exchanger system with its own fuel inventory and its own heavy-water slurry to light-water-solution transition. These wall be slurry/solution loops with individual problems associated with temperature-gradient-driven deposit formation.
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From page 256... ...
I I Calcination Am/Cm | fp To Transmuter Waste Source: Los Alamo s National Laboratory (1992) TECHNOLOGIES FOR SEPARATIONS AND TRANSMUTATION Fission Product Off-gas 1, Xe, Kr, Br, Bu | Liquid lon Dissolution :| Exchange | l Np/Pv 1 Tc, Pd 1 1 Denitrati~n I I Tc Volatilization _ ..
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From page 257... ...
APPENDIXF- TRANSMUTATIONCONCEPTS FIGURE F-14 Ozonolysis option for technetium/ruthen~um separation. STOOD D2 1 Transmuter _< Pump r 257 o3 11 ~ 1 .
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From page 258... ...
The concept would generate 75% of its thermal energy from fission of actinides formed by neutron absorption in thorium, roughly equivalent to a breeding ratio of 0.75. The remaining fissions would be from TRUs obtained from EWR spent fuel.
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From page 259... ...
] -~- a 239 FIN F-15 ~d dowsing fir 1.0-~ Neons NEW reeled fib spent ~ gel.
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From page 260... ...
260 TECHNOLOGIES FOR SEPARATIONS AND TRANSMUTATION FIGURE F-16 Matenal flowsheet for I.O-GWe nonaqueous ATW fi~eled with thonum and spent EWR fi~el. Fuel Fissioned | 0.96 Mg HM Feed Spent ~ ~ 46.10 Mg HM LWR Thorium2.18 Mg TRTh Fuel Ore1.65 Mg U 0.32 Mg Pu 0.25 Mg HM 0.76 Mg HM 0.25 Mg TRU 0.76 Mg Th 0.23 Mg Pu Reprocess~ng 14.11 MgHM Makeup ~0.61 Mg TRTh 0.52 Mg U 0.03 Mg Pu I Loss 0.05 Mg HM 1 1 Radioactive Waste Repository Blanket 0.8 GeV, 110 mA tl = 0.333.
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From page 261... ...
APPENDIX F - TRANSMUTA TION CONCEPTS FIGURE F-17 Mater~al flowsheet for I.O-GWe nonaqueous ATW fueled with thorium. Fuel Fissioned 0.92 Mg HM 1 | Thorium Ore Feed 56.19 Mg HM 2.19 Mg TRTh 2.01 Mg U 0.04 Mg Pu l ~Makoup 0.98 Mg HM 0.98 Mg Th 261 Blanket 0.8 GeV, 55 mA = 0.347, L= 0.80 5.76 Mg HM 0.23 Mg TRTh 0.21 Mg U < 0.01 Mg Pu Reprocessing 17.27 Mg HM 0.69 Mg TRTh 0.63 Mg U 0.01 Mg Pu 1 1 Loss ~ ~ 0.06 Mg HM Radioactive Waste Repository Disharge 55.27 Mg HM 2.19 Mg TRTh 2.01 Mg U 0.04 Mg Pu .<
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From page 262... ...
NONAQUEOUS REPROCESSING OF LWR SPENT FI1EL For the nonaqueous ATW, fueled with a solution of TRUs in molten fluorides, LANE describes entirely different separation processes. The separation of TRUs and fission products from LWR spent fifes is to be carried out in a separate facility, as in the case of the aqueous ATW.
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From page 263... ...
However, mechanical deciadding of EWR spent fuel has been proven successful in current commercial reprocessing operations in France, the United Kingdom, and Japan. There are good reasons why such a process may be attractive for low TRU, low 238U z~rconium-uranium alloy spent filet from naval reactors.
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From page 264... ...
The pure liquid phases have to be above their melting points to obtain the high decontamination factors and discharge concentrated wastes. The light lithium fluoride melts at 848 ° C and the eutectic with beryllium fluoride at about 350° C at about 50 mole percent.
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From page 265... ...
Safety Issues and Reactivity Control LANE states that the main benefit from the accelerator would be to allow use of a subcritical reactor for neutron multiplication, thereby avoiding the criticality safety issues of critical reactors and possibly the public issues on nuclear power. Clearly, in this concept neutron multiplication can be stopped quickly by terminating the beam current impinging on the spaHation target.
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From page 266... ...
materials that produce large numbers of neutrons per proton, because the ATW systems require high (thermal) neutron fluxes to effectively fission some of the MAs before they decay to nonfissile forms, the power densities in the targets will be large, and for economic reasons the target must withstand high proton/neutron fluences.
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From page 267... ...
However, in the ATW fluid-fuel reactor concepts, there are pipes continuously carrying highly active fluid fuel that contain actinides and fission products Dom the reactor vessel. In the aqueous ATW the fluid fuel is itselfthe main coolant as it flows from the reactor to an external heat exchanger.
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From page 268... ...
Thermal reactors with sufficiently low neutron leakage and sufficiently high neutron flux tend to undergo large spatial oscillations in neutron flux and power density, even if the total power is held constant. The oscillations appear in the form of traveling waves of neutron flux and power density, usually traveling az~muthaDy around a cylindrical reactor core.
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From page 269... ...
Because xenon is not highly soluble in fluids, it is possible that xenon gas may escape from the fluid fuel ranidIv enough to suppress xenon oscillations. -- ~-~- ~ -- ~ -~~~~ -em- -or -- -- -- Jo -- -- -~rr~~~~ ~ -- -- - The aqueous ATW may perform better in this regard, because large amounts of a stoichiometric mixture of deuterium and oxygen are expected to be produced from radiolytically decomposed heavy water that carries the suspension of fuel particles.
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From page 270... ...
The short turnaround cycle for the final in the heavy-water reactor system is designed to isolate the rare earths, such as samaricium, quickly. The nonaqueous ATW fueled partly or completely with thorium will be subject to another reactivity transient that is a potential safety issue at high neutron flux.
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From page 271... ...
PRESSURE-TUBE FAILURE Fluid-fi~e} boundary-layer heating is more severe the higher the neutron flux. In the aqueous ATW concept, the failure of a pressure tube can lead to pressurized hot fuel slurry ejecting into the surrounding moderator or steam generator.
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From page 272... ...
For the nonaqueous ATW concepts, the accelerator consumes a considerably lower fraction of the electrical power. For example, Table F-3 shows that the nonaqueous EWR-fueled ATW-2 produces a net electrical power of 2,180 MWe at rated capacity, which is 36% higher than that of the ATW- I, while the smaller ATW-2 accelerator requires only 44°/O of the beam current of the ATW- ~ accelerator at half the beam voltage.
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From page 273... ...
To realize the potential advantages of using aqueous reprocessing technology, which is more highly developed than that used in the nonaqueous ATW, the features of a just-critical aqueous ATW without accelerator should be carefi~lly examined by LANL. Of course, the very high fissile specific power associated with the thermal neutron flux, 3 x 10~5 neutrons/cm2.s -- and the attendant high rates of radionuclide destruction and heat production -- would present materials and engineering design challenges for fuel and reactor proper, with or without the accelerator.
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From page 274... ...
Superconducting cavity linacs inherently have higher gradients arid thus potentially lower capital costs. Based on the estimated RF-to-beam efficiency of 84%, a superconducting cavity linac appears to present no significant advantage in operating costs.
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From page 275... ...
They are also consistent With values demonstrated within the Strategic Defense Initiative's supported Neutral Particle Beam program. There are currently klystrons to provide high-power continuous wave RF (0.5 to 1 WOW)
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From page 276... ...
This could furnish the TRU feed for about ~ 5,000 MWt of ATW power for the ATW concepts that transmute only TRUs and fission products from EWR spent fuel. This would require a commitment to build a significant number of ATWs.
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From page 277... ...
aqueous ATW because of the extreme radioactivity of the fluid fuel and because large increases in nuclear reactivity could result. As an additional precaution, LAN: proposes that each calandria tube be two concentric Zircaloy pressure tubes, each capable of withstanding the pressure difference between the hot fluid fuel and the relatively coo} heavy-water moderator.
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From page 278... ...
Techniques used in the aqueous homogenous reactor experiment, involving vortex flow in the reactor core to rapidly separate the radiolytic gases, are probably not applicable to flow in a long small-diameter process tube. No large power reactor has operated at the neutron fluxes contemplated for the aqueous ATW.
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From page 279... ...
, ~ . come Development of chemical processing of L,WR spent fuel by nonaqueous halide techniques has been done for special fiaels in a program of the DOE, but not at the scale and recoveries needed for the ATW.
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From page 280... ...
Compared with modern solid-fuel nuclear power reactors, both the aqueous and nonaqueous ATW concepts would encounter severe material problems and new safety problems because of the very high thermal neutron fluxes, the use of fluid fuels and fluid targets, the high power densities, and the use of continuous integrated chemical processing with short turnaround times. Examples of problems associated with each of the two concepts have been suggested earlier and are expanded.
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From page 281... ...
The many issues here reflect a very immature technology. The chemical processing proposed for the ATW concepts is beyond the state of industnal experience because of both the radiation fluxes involved and the ~.
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From page 282... ...
Within this envelope a demonstration of a completely integrated ATW accelerator front end in continuous wave operation could be expected. A funneling demonstration with two beams would be an essential element to remove remaining concerns about this new system.
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From page 283... ...
APPENDIXF- TRANSMUTATIONCONCEPTS 283 FIGURE FITS Program for ATW accelerator design and engineering development. Year 1 Year 2 Conceptual Design Detailed Design Component Development lon Source/lnjector 700-MHz RF Tube RFQ Test DTL Section Test CCL Section Test Beam Switcher Cavity Totals ($Millions)
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From page 284... ...
2~ ~ ~< age FIN F-lg capstones fir FEW d~dopmem.
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From page 285... ...
was proposed as part of a system for the transmutation of HEW, with the ultimate goal of significantly reducing, if not eliminating, the long-term risk of a geologic repository. The PER concept, which is a thermal reactor with a high neutron flux, has the potential to burn up fission products as well as the MAs.
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From page 286... ...
Cold Frit 1 \ \ ~ Fuel/Target Particles \ \ Hot Frit \ -- - Outlet Helium Channel SOURCE: Brookhaven National Laboratory ;; ~ :!
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From page 287... ...
Transmutation Performance Requirements The PBR was proposed by BNL as a transmutor for the MAs, some of the plutonium, and long-lived fission products from EWR spent fuel. The remaining plutonium is meant to be used in future reactors that accept MOX fuel.
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From page 288... ...
l 1 WASTE STREAM SEPARATOR (PARTITIONING) STREAM C STREAM D STREAM E STREAM P LONG LIVED FISSION PRODUCTS Tc99 & 1129 Csl37&Srl29r STABLE & SHORT-LIVED ISOTOPES Source: Brookhaven National Laboratory RECYCLE TO t l STREAM At URANIUM STREAM B ~ PLUTONIUM 1 ~ BURIAL POWER GENERATION OR CONSUMPTION MINOR ACrINIDE!
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From page 289... ...
Thus, if the PBR Unctions as proposed, it wait be capable of reducing the inventory of actinides at a rate faster than the integral fast reactor, but comparable to the AlW. If the assumption is made that the PBR should accommodate all the discharged plutonium from the EWRs and be used for electricity generation, it is possible to define the inventory reduction factors for all three concepts both in the total system (see Figure F-22)
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From page 290... ...
290 TECHNOLOGIES FOR SEPARATIONS AND TRANSMUTATION FIGURE F-22 Transmutation device operation time (total system)
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From page 291... ...
APPENDIXF- TRANSMUTATIONCONCEPTS FIGURE F-23 Transmutation device operation time (repository)
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From page 292... ...
The MAs and fission products are sent to the target processing facility. The PER fuel is first sent to an electrodissolver to remove the carbon, which is then sent to the filet fabrication facility.
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From page 293... ...
APPENDIXF- TRANSMUTATIONCONCEPTS FIGURE F-24 PUREX/TRUEX reprocessing for I~WR fuel. MAKE UP U02 LWR SPENT FUEL HLW PU, RU,TC CS, SR AND I TO PER REPROCESSING FUEL PUREX TRUEX SOURCE: Brookhaven National Laboratory 293 1 FUEL FABRICATION U AND PU To LLW DISPOSAL OF 10 TO 106
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From page 296... ...
The environmental implications of the PBR are in many ways similar to the other transmutor concepts. Thus, the impact of reduced demand for uranium ore on the risk to the public health is a positive attribute.
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From page 297... ...
These costs appear not to include the developmental cost of the chemical separation processes. SYSTEMS COSTS Only rough estimates have been made for capital costs.
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From page 298... ...
_ ~ 7.51 ~T/Yr Cs&Sr Interim ~_' storage) ' 75 MTrtr Remaining Fission Products Repository Increased Viability 1.05 NlT/Yr FPs ?
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From page 299... ...
This is not necessarily an optimal set of beam conditions, but a high energy is desirable for purposes of distributing the beam load through the target thickness, and as high a current as possible is desirable from the point of view Of mating the neutron flux and hence the burn rate. In any case, these beam parameters are believed to be achievable.
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From page 300... ...
300 TECHNOLOGIES FOR SEPARATIONS AND TRANSMUTATION FIGURE F-28 Comparison of inventory reduction factor for the Phoenix and ALMR scenarios. 160 140 120 -a 100 80 60 40 Total Inventory Reduction Factor Decontamination Factor=1000 .
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From page 301... ...
_ Protons ~ ,~ / ~(_) Note: Output, Per Year: ~Intermedlate 1.05 Tonnes FPs Sodium System 1.55 Tonnes Pu Not Shown ten' -300 kg Xenon auf Source: Brookhaven National Laboratory
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From page 302... ...
, which may introduce some transmutation effects not considered in fast reactors (see below)
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From page 303... ...
. Hence, the effective plant As noted earlier the system requires both front-end processing of EWR spent fuel and intermediate processing of the Phoenix targets.
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From page 304... ...
3. intermediate reprocessing of Phoenix targets to separate plutonium and fission products from the MAs and iodine from the xenon products; again process decontamination factors of 106 would be required if the "minimum objective" for a transmutes is to be met by Phoenix; and 4.
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From page 305... ...
Of somewhat unique concern is the potential for Na-D2O reactions between the sodium-cooled MA targets and the D2O-cooled and moderated iodine blanket. LICENSING Licensing a Phoenix facility, a combination of a large accelerator and a near-critical fast reactor, can draw on issues and procedures developed for the component facilities to date, but new safety issues associated with operating the combination wall have to be identified and resolved.
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From page 306... ...
long-term risk reduction in nuclear waste management. RISK Risk analyses will have to include: · decreased risk from uranium-m~n~ng/m~lling as a result of plutonium recycle and energy generation from actinide burning, · increased short-term risks associated with transmutation and separations operations and surface storage versus disposal of radioisotopes, and · reduced long-term risks associated with inventory reductions of long-lived and watersoluble isotopes.
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From page 307... ...
These may be exacerbated, however, if process decontamination factors of 10~0 are required in full-scale reprocessing plants to meet the "minimum objective." Additional waste: Additional waste generated by systems (contamination of filet cladding hulls arid separations equipment, radioactivation of Phoenix system components, etc.) has not been addressed.
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From page 308... ...
1989. Nuclear Fuel Cycle in the 1990s and Beyond the Century: Some Trends and Foreseeable Problems.
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From page 309... ...
1987. Review of Nuclear Fuel Cycle Costs for the PWR and Fast Reactor.
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From page 310... ...
1978. Report to the American Physical Society by the Study Group on Nuclear Fuel Cycles and Waste Management.
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From page 311... ...
1992. The Economics of the Nuclear Fuel Cycle (draR)
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From page 312... ...
1987. International Safeguards for a Modern MOX Fuel Fabrication Facility.
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From page 313... ...
1990. As quoted in Watkins pushing integral fast reactor.
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Key Terms
This material may be derived from roughly machine-read images, and so is provided only to facilitate research.
More
information on Chapter Skim is available.