Energy sustainability and economic stability with Breed and Burn reactors

Greenspan, E.; Heidet, Florent

doi:10.1016/j.pnucene.2011.05.002

Cited by 31 publications

(17 citation statements)

References 3 publications

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“…Compared with the reference core (Fig. 13), the shorter S&B cores feature (1) higher neutron leakage out of the active core, (2) smaller blanket power fraction, (3) smaller HM inventory and higher specific power, (4) larger burnup reactivity swing per year and increased number of seed batches, (5) shorter cycles, (6) higher average discharge burnup of seed fuel due to the smaller axial power peaking factor, (7) slightly larger reprocessing capacity per unit of electricity but still about 1=5 that of the ABR (Ref. 15), (8) significantly less positive feedback to coolant voiding due to the enhanced leakage induced by coolant expansion, and (9) more negative feedback to core axial and radial expansion due to the larger core leakage.…”

Section: Vb Core Heightmentioning

confidence: 99%

“…[3][4][5] It is expected that B&B reactors can improve the economics of fast reactors and the uranium utilization relative to that of present light water reactors (LWRs) as they require no fuel reprocessing and the feed fuel is easy to fabricate. 6 However, in order to sustain the B&B mode of operation, it is necessary to fission at least~20% of the initial depleted uranium feed. 7 An average burnup of 20% fissions per initial metal atom (FIMA) corresponds to a peak discharge burnup of up to 30% FIMA and the peak radiation damage on the cladding material in the vicinity of 500 displacements per atom 8,9 (dpa).…”

Section: Introductionmentioning

confidence: 99%

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Advanced Burner Reactors with Breed-and-Burn Thorium Blankets for Improved Economics and Resource Utilization

2017

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-This paper assesses the feasibility of designing seed-and-blanket (S&B) sodium-cooled fast reactor (SFR) cores to generate a significant fraction of the core power from radial thorium-fueled blankets that operate in the breed-and-burn (B&B) mode. The radiation damage on the cladding material in both seed and blanket does not exceed the presently acceptable constraint of 200 displacements per atom (dpa). The S&B core is designed to have an elongated seed (or driver) to maximize the fraction of neutrons that radially leak into the subcritical B&B blanket and reduce the neutron loss via axial leakage. A specific objective of this study is to maximize the fraction of core power generated by the B&B blanket that is proportional to the neutron leakage rate from the seed to the blanket. Since the blanket feed fuel is very inexpensive and requires no reprocessing and remote fuel fabrication, a larger fraction of power from the blanket will result in a lower fuel cycle cost per unit of electricity generated by the SFR core. It is found possible to design the seed of the S&B core to have a lower transuranics (TRU) conversion ratio (CR) than a conventional advanced burner reactor (ABR) core without deteriorating core safety. This is due to the unique synergism between a low CR seed and the B&B thorium blanket. The benefits of the synergism are maximized when using an annular seed surrounded by inner and outer thorium blankets. Two high-performance S&B cores are designed to benefit from the annular seed concept: (1) an ultra-long-cycle core having a CR = 0.5 seed and a cycle length of~7 effective full-power years (EFPYs) and (2) a high-transmutation core having a TRU CR of 0.0. The TRU transmutation rate of the latter core is comparable to that of the reference ABR with a CR of 0.5, and the thorium blanket can generate close to 60% of the core power. Because of the high blanket power fraction along with the high discharge burnup of the CR = 0 seed, the reprocessing capacity per unit of core power required by this S&B core is only approximately 1/6th that of the reference ABR core with a TRU CR of 0.5. Although the seed fuel CR is nearly zero, the burnup reactivity swing is low enough to enable a cycle length of more than 4 EFPYs. This is attributed to a combination of reactivity gain in the thorium blankets over the cycle and the relatively high heavy metal inventory. Moreover, despite the very low leakage, the S&B cores feature a less positive coolant reactivity coefficient and large enough negative Doppler coefficient even when using nonfertile fuel for the seed, because of the unique physics properties of the 233 U and Th in the thorium blankets. With the long cycles, the S&B SFR is expected to have a higher capacity factor, and therefore a lower cost of electricity, than conventional ABRs. The discharge burnup of the thorium blanket fuel is typically 70 MWd/kg such that the thorium fuel utilization is approximately 12 times that of natural uranium in light water reactors. A sensitivity study is subsequently un...

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Section: Vb Core Heightmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Advanced Burner Reactors with Breed-and-Burn Thorium Blankets for Improved Economics and Resource Utilization

2017

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“…The minimum burnup required for sustaining the B&B mode of operation, as well as the maximum burnup that can be achieved if fuel reconditioning could be implemented, were established in previous studies [15,[17][18][19][20][21]. It is insightful to estimate these values using a simple neutron balance analysis that counts the number of neutrons that are absorbed and that are generated by fissions in a unit volume of fuel as a function of burnup in the core, starting from the fresh feed fuel.…”

Section: Neutron Balance Analysismentioning

confidence: 99%

“…It is insightful to estimate these values using a simple neutron balance analysis that counts the number of neutrons that are absorbed and that are generated by fissions in a unit volume of fuel as a function of burnup in the core, starting from the fresh feed fuel. The minimum required burnup is the lowest burnup (BU m ), other than zero, for which Equation (1) is satisfied where the maximum attainable burnup is the largest BU m for which Equation (1) is satisfied [15,[17][18][19][20][21].…”

Section: Neutron Balance Analysismentioning

confidence: 99%

A Phased Development of Breed-and-Burn Reactors for Enhanced Nuclear Energy Sustainability

Greenspan

2012

Sustainability

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Several options for designing fast reactors to operate in the Breed-and-Burn (B&B) mode are compared and a strategy is outlined for early introduction of B&B reactors followed by a gradual increase in the fuel utilization of such reactors. In the first phase the fast reactor core will consist of a subcritical B&B blanket driven by a relatively small critical seed. As the required discharge burnup/radiation-damage to both driver and blanket fuel had already been proven, and as the depleted uranium fueled B&B blanket could generate close to 2/3 of the core power and will have very low fuel cycle cost, the deployment of such fast reactors could start in the near future. The second phase consists of deploying self-sustaining stationary wave B&B reactors. It will require development of fuel technology that could withstand peak burnups of ~30% and peak radiation damage to the cladding of ~550 dpa. The third phase requires development of a fuel reconditioning technology that will enable using the fuel up to an average burnup of ~50%-the upper bound permitted by neutron balance considerations when most of the fission products are not separated from the fuel. The increase in the uranium ore utilization relative to that provided by contemporary power reactors is estimated to be 20, 40 and 100 folds for, respectively, phase 1, 2 and 3. The energy value of the depleted uranium stockpiles ("waste") accumulated in the US is equivalent to, when used in the B&B reactors, up to 20 centuries of the total 2010 USA supply of electricity. Therefore, a successful development of B&B reactors could provide a great measure of energy sustainability and cost stability.

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“…Sodium-cooled Breed-and-Burn (B&B) fast reactors were proposed (Greenspan and Heidet, 2011;Ellis et al, 2010;Sekimoto et al, 2001;Driscoll et al, 1979) to make beneficial use of the large stockpiles of depleted uranium without need for fuel enrichment and reprocessing technologies beyond the provision of enriched fuel for establishing initial criticality. The minimum average burnup required for sustaining the B&B mode of operation is close to 20% Fissions per Initial Metal Atom (FIMA).…”

Section: Introductionmentioning

confidence: 99%

Improved resource utilization by advanced burner reactors with breed-and-burn blankets

Zhang

Fratoni

Greenspan

2018

Progress in Nuclear Energy

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A B S T R A C TPrevious studies assessed the feasibility of designing Sodium-cooled Fast Reactors (SFR) in a novel Seed-andBlanket (S&B) configuration in which a significant fraction of the core power is generated by a radial metallic thorium-fueled blanket that operates in the Breed-and-Burn (B&B) mode. The radiation damage on the cladding material in both seed and blanket does not exceed the presently acceptable constraint of 200 Displacements per Atom (DPA). This paper investigates a number of blanket fuel options other than metallic thorium fuel, including thorium dioxide fuel, thorium hydride fuel, thorium nitride Fully Ceramic Encapsulated (FCM) fuel, and Pressurized Water Reactor (PWR) Used Nuclear Fuel (UNF) after limited reprocessing. Since the neutron spectrum of the oxide fueled blanket is softer than that of the reference metallic thorium fueled blanket, it can discharge its fuel at an average burnup of around 110 MWd/kg versus 65 MWd/kg of the metallic thorium. The two thorium hydride fueled blankets feature an even softer neutron spectrum than the oxide fueled blanket and, therefore, a higher average discharge burnup -192 MWd/kg and 245 MWd/kg when the H-to-Th ratio is, respectively, 0.5 and 2.0. The FCM fuel is composed of SiC matrix and cladding that is expected to self-anneal the neutrons induced damage. With the assumption that the FCM fuel will indeed be proven not limited by radiation damage, its discharge burnup could be up to 482 MWd/kg. As a result, the corresponding thorium utilization is the highest of all options examined -close to 80 times the utilization of natural uranium in present Light Water Reactors (LWRs). The amount of Trans-Th isotopes accumulated in the thorium blanket per unit of generated electricity decreases as the blanket fuel is discharged at a higher burnup. Therefore, a higher discharge blanket burnup results in lower long-term radioactivity and radiotoxicity. It is also found that the 232 U/ 233 U ratio in the discharged thorium fuel is over 3 times higher in the thorium hydride than in the other blankets thus improving the thorium-hydride blanket's proliferation resistance. Softening of the blanket spectrum leads to softening of the seed spectrum region interfacing with the blanket and this enables to discharge the seed fuel at a higher average burnup. The higher discharge burnup of the seed fuel reduces the required reprocessing and fuel fabrication capacities per unit of generated electricity. The cores having softer neutron spectrum blankets also feature less positive feedback to sodium voiding and much more negative Doppler coefficient. When PWR UNF is used after limited reprocessing to fuel the blanket, the subcritical blanket driven by the excess neutrons from the seed can discharge this fuel at an average burnup of ∼120 MWd/kg. Combined with the burnup in the first stage PWRs, this two-stage energy system can achieve an accumulated uranium burnup of ∼170 MWd/kg. This increases the fuel utilization of natural uranium by a factor of three relative to oncethroug...

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Energy sustainability and economic stability with Breed and Burn reactors

Cited by 31 publications

References 3 publications

Advanced Burner Reactors with Breed-and-Burn Thorium Blankets for Improved Economics and Resource Utilization

Advanced Burner Reactors with Breed-and-Burn Thorium Blankets for Improved Economics and Resource Utilization

A Phased Development of Breed-and-Burn Reactors for Enhanced Nuclear Energy Sustainability

Improved resource utilization by advanced burner reactors with breed-and-burn blankets

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