The Coal-Uranium Breeder: Uranium from coal

Evidence exists that much of the coal in the Western United States contains an appreciable amount of uranium. While not concentrated enough to be directly considered as a uranium resource, this uranium is enriched in the ash remaining after the coal is burned. Consequently, some coal ashes have concentrations of uranium which would classify them as intermediate-grade uranium ores (100–500 ppm). A combined facility, herein named a Coal-Uranium Breeder, which generated electricity or gas from coal and processed the ash to produce uranium could make available more nuclear energy than it consumed as fossil energy, depending on the reactor type and other variables. A considerable lessening of environmental impact is possible through the use of combined rather than separate coal plants and uranium mills. Potentially, a large fraction of U.S. uranium needs could be supplied at a reasonable cost and thus eliminate the apparent shortfall of sandstone uranium ores and delay the decision about the breeder reactor. More effort is needed to develop extraction techniques and to determine the uranium content of coals.     

Logistical and economic obstacles to a fast reactor programme

Fast reactor studies used to place great emphasis on its role as a breeder of plutonium, thereby raising the prospect of a nuclear power system free from the constraint of uranium supplies. Today, not only the timing of fast reactor introduction has slipped (by two or three decades) but the perspective which was central to energy policy has changed dramatically. This article first examines the fast reactor as a system and looks at the interaction of four key variables in its logistics. It then looks at the rise in real costs, especially capital costs. Given the parameters that determine the plutonium balance and the economics of the fast reactor system, the author questions whether there is a sound basis for its introduction, and concludes by suggesting that the most pressing requirement is a study of the opportunity costs of fast reactor R&D expenditures.     

The urgency of the fast breeder …- to delay or not?

In the December 1976 issue of Energy Policy Leslie Grainger expressed his doubts that nuclear power could in the short term contribute effectively to UK energy requirements. He suggested particularly that introduction of the fast breeder reactor was unlikely to ease quickly the burden of uranium imports for thermal reactors. Here Burt Cutts, Head of Central Technical Services at UKAEA, Risley, takes issue with Grainger's viewpoint.     

Status of helium-cooled nuclear power systems

Helium-cooled nuclear power systems offer a great potential for electricity generation when their long-term economic, environmental, conservation and energy self-sufficiency features are examined. The high-temperature gas-cooled reactor (HTGR) has the unique capability of providing high-temperature steam for electric power and process heat uses and/or high-temperature heat for endothermic chemical reactions. A variation of the standard steam cycle HTGR is one in which the helium coolant flows directly from the core to one or more closed cycle gas turbines. The effective use of nuclear fuel resources for electric power and nuclear process heat will be greatly enhanced by the gas-cooled fast breeder reactor (GCFR) currently being developed. A GCFR using thorium in the radial blanket could generate sufficient U-233 to supply the fuel for three HTGRs, or enough plutonium from a depleted uranium blanket to fuel a breeder economy expanding at about 10% per year. The feasibility of utilizing helium to cool a fusion reactor has been included in most research studies on thermonuclear fusion and is also discussed in this paper. This paper summarizes the status of helium-cooled nuclear energy systems as a basis for assessing their prospects.     

Pricing offshore wind power

Offshore wind offers a very large clean power resource, but electricity from the first US offshore wind contracts is costlier than current regional wholesale electricity prices. To better understand the factors that drive these costs, we develop a pro-forma cash flow model to calculate two results: the levelized cost of energy, and the breakeven price required for financial viability. We then determine input values based on our analysis of capital markets and of 35 operating and planned projects in Europe, China, and the United States. The model is run for a range of inputs appropriate to US policies, electricity markets, and capital markets to assess how changes in policy incentives, project inputs, and financial structure affect the breakeven price of offshore wind power. The model and documentation are made publicly available.     

High-temperature nuclear heat source for hydrogen production

The combination of nuclear breeder reactors and thermal converters can efficiently utilize uranium and thorium reserves and is a worldwide energy source which is potentially 20 times greater than coal. The very high temperature reactor (VHTR), a thermal converter, can be coupled to open and closed cycle processes to produce hydrogen in large quantities. Current work in the U.S. is focused on the design of a VHTR of about 850 MW(t). The thermal rating and the design are similar to those of the steam cycle Fort St Vrain (FSV) reactor built in Colorado, U.S., but an intermediate helium circuit and a core outlet temperature of 925–950°C are used. Hydrogen production using this reactor would be approximately 10 kg/sec with a carbon-based process or 3 kg/sec with a closed-loop thermochemical process.     

Impact of environmental values on the breakeven price of switchgrass

This study estimates the farm-gate breakeven price of switchgrass relative to wheat in Oklahoma, USA. The breakeven price of switchgrass is determined for two situations: when external consequences are ignored and when the environmental costs of changes in soil erosion, fertilizer (nitrogen and phosphorous) runoff, and soil organic carbon (SOC) are considered. Results suggest that if indirect land use changes are ignored, the farm-gate breakeven price of switchgrass when only the internal costs are considered is 69%–144% greater (depending on land quality) than if the value of selected external consequences are considered. The potential environmental benefits are greater if highly erodible land is switched from annual cropping to switchgrass.     

Steps toward passively safe, proliferation-resistant nuclear power

After about a 30-year hiatus of construction in the US but not in all involved countries, the designs for an improved water-cooled nuclear reactor will hopefully be developed by a consortium of nuclear reactor builders and users under an agreement with the US Department of Energy (DOE) and review by the Nuclear Regulatory Commission (NRC). The construction of high-temperature, helium-cooled pebble-bed or prismatic reactors may herald the entry of new, safer, and less costly types of reactors to replace the water-cooled reactors of the past and current types. Nuclear breeder reactors hold the promise of limitless energy supplies without the use of fossil fuels or renewables at acceptable costs but this development program has been stalled periodically, especially in the US, when abundant low-cost uranium sources were added to the supply side.     

A neutronic investigation on a helium cooled hybrid reactor using nitride fuels containing reactor grade plutonium

There has been a significant amount of reactor grade (RG) plutonium accumulated from the conventional nuclear reactors’ spent fuel. Destruction or reducing this RG plutonium is very important to prevent its misuse and/or release accidentally into the environment. Using very energetic fusion neutrons in fusion–fission (hybrid) reactors can burn the RG plutonium effectively. This study presents the burning of the mixed fuel containing RG plutonium and uranium in a helium cooled hybrid reactor for an operation period of 24 months. Effect of various fuel mixtures and tritium breeders on the neutronic performance of the reactor as well as the burning of the RG plutonium was investigated. Calculations were carried out on an experimental hybrid blanket with the aid of SCALE4.3 by solving the Boltzmann transport equation with the XSDRNPM code. Numerical results showed that increasing RG plutonium content in the fuel increased the burning of plutonium and fusion energy multiplication substantially. The tritium breeder having the lowest lithium atomic density allowed the highest fission of the fuel in the blanket.     

Breakeven price of biomass from switchgrass,big bluestem,and Indiangrass in a dual-purpose production system in Tennessee

The objective was to determine the breakeven price for switchgrass (SG) (Panicum virgatum L.), a mix of big bluestem (Andropogon gerardii Vitman) and Indiangrass (BBIG) (Sorghastrum nutans L. Nash), and a combination of SG and BBIG (SG/BBIG) produced under three harvest treatments. Two-harvest treatments included a forage harvest at early boot (EB) and at early seedhead (ESH) plus a biomass harvest at fall dormancy (FD). The third harvest treatment was a single biomass harvest at FD. Mixed models were used to determine if there were differences in yield, crude protein, and nutrient removal for each of the native warm-season grass (NWSG) treatments at each harvest. The EB plus FD harvest system would be preferred over the ESH plus FD harvest system for all NWSG treatments. BBIG was the only NWSG treatment with a breakeven price for biomass that decreased with an EB harvest. For all three NWSG treatments, a producer would be better off harvesting once a year for biomass than twice for forage and biomass. The cost of harvesting and replacing the nutrients for the forage harvest was greater than the revenue received from selling the forage.     

The future cost of uranium enrichment: Technology and economics

The cost of uranium enrichment is the most important factor determining the fuel cost of nuclear energy. This paper attempts to forecast the future direction of the price of separative work by examining the forces that determine it. It is argued that the interplay among the characteristics of enrichment technologies, the structure of the international market, and the balance of supply and demand determine the enrichment price. The analysis indicates that all forces point towards a price much lower than the current one. It is predicted that, depending on the technological advances, the price of separative work unit for uranium enrichment will range between $40 and $90 by the year 2000.     

Industrial sugar beets to biofuel: Field to fuel production system and cost estimates

Specialized varieties of sugar beets (Beta vulgaris L.) may be an eligible feedstock for advanced biofuel designation under the USA Energy Independence and Security Act of 2007. These non-food industrial beets could double ethanol production per hectare compared to alternative feedstocks. A mixed-integer mathematical programming model was constructed to determine the breakeven price of ethanol produced from industrial beets, and to determine the optimal size and biorefinery location. The model, based on limited field data, evaluates Southern Plains beet production in a 3-year crop rotation, and beet harvest, transportation, and processing. The optimal strategy depends critically on several assumptions including a just-in-time harvest and delivery system that remains to be tested in field trials. Based on a wet beet to ethanol conversion rate of 110 dm³ Mg⁻¹ and capital cost of 128 M$ for a 152 dam³ y⁻¹ biorefinery, the estimated breakeven ethanol price was 507 $ m⁻³. The average breakeven production cost of corn (Zea mays L.) grain ethanol ranged from 430 to 552 $ m⁻³ based on average net corn feedstock cost of 254 and 396 $ m⁻³ in 2014 and 2013, respectively. The estimated net beet ethanol delivered cost of 207 $ m⁻³ was lower than the average net corn feedstock cost of 254–396$ m⁻³ in 2013 and 2014. If for a mature industry, the cost to process beets was equal to the cost to process corn, the beet breakeven ethanol price would be $387 m^-3 (587 $ m⁻³ gasoline equivalent).     

Integral measurements in a simulated fast breeder reactor blanket

Much of the breeding of fissile material and a significant fraction of the energy production in proposed fast breeder reactors will occur in a blanket of fertile material surrounding the reactor core. Current uncertainties in neutron cross sections and calculational methods have much greater significance for blanket design than for core design. The Purdue University Fast Breeder Blanket Facility (FBBF), designed to simulate the neutron behavior in fast breeder reactor blankets, has recently been completed. The facility is now being used to perform integral neutron reaction rate measurements. Such measurements provide tests of nuclear cross sections and calculational methods used in the design of fast breeder reactor blankets.     

Economic feasibility of producing sweet sorghum as an ethanol feedstock in the southeastern United States

This study examines the feasibility of producing sweet sorghum (Sorghum bicolor (L.) Moench) as an ethanol feedstock in the southeastern United States through representative counties in Mississippi. We construct enterprise budgets along with estimates of transportation costs to estimate sweet sorghum producers’ breakeven costs for producing and delivering sweet sorghum biomass. This breakeven cost for the sweet sorghum producer is used to estimate breakeven costs for the ethanol producer based on wholesale ethanol price, production costs, and transportation and marketing costs. Stochastic models are developed to estimate profits for sweet sorghum and competing crops in two representative counties in Mississippi, with sweet sorghum consistently yielding losses in both counties.     

Review of cost estimates for uranium recovery from seawater

The 4.5 billion tonnes of uranium in seawater is sufficient to power the world's reactor fleet for 13,000 years. For decades, the transformative potential of this enormous resource has prompted interest in technologies for recovering uranium from seawater. Since the 1960s, though, cost analyses of such technologies have failed to convincingly demonstrate a cost-competitive alternative to conventional uranium recovery from terrestrial mining. Hence, uranium from seawater has come to be considered as a backstopping technology that has the potential to establish a price ceiling for the uranium resource. Such an upper bound is valuable because it removes uncertainty surrounding uranium prices when developing and deploying nuclear power systems. This paper reviews cost estimates as the technology has evolved over the past five decades. During this time, systems that actively moved seawater gave way to those where the adsorbent sits passively in seawater. The adsorbent material changed from hydrous titanium oxide to the higher-capacity amidoxime ligand. Early efforts used amidoxime grafted onto an acrylic substrate, which was later replaced by polyethylene because of its increased durability and lower cost. The review shows that capacity, in grams of U per kilogram of adsorbent, is a strong driver of cost along with reusability of the adsorbent. The most recent estimates reviewed are seen to place the U production cost at $400–$1000/kg of U, several times higher than the 2014 spot market price, which has remained near or below $100/kg of U.     

中国核电发展战略研究

中国能源资源品种丰富,人均占有量较少;能源资源结构不尽合理;能源资源分布与生产力布局不平衡。核电作为清洁能源,其基本特性决定了在应对能源挑战中有能力发挥无可替代的重要作用,我国在现阶段发展核电是调整能源布局的有效途径。中国核电已形成规模化批量化发展格局。二代改进型压水堆核电站随着技术的发展和运行经验的反馈．逐步引入新的成熟技术,使核电站的安全性得到进一步的提高。更应积极消化吸收第三代核电技术,使其安全目标更高、技术更先进。加快开发快中子增殖堆核电站、构建核燃料循环体系．可以将铀资源的利用率由普通的热堆的不足1％。提高到60％～70％,从而有效防止铀资源枯竭的威胁。     

Slow and stunted: Plutonium accounting and the growth of fast breeder reactors in India

The Indian Department of Atomic Energy (DAE) has projected a large growth of nuclear power in the country predominantly based on breeder reactors. These projections use a simplistic methodology that does not carefully account for the availability of plutonium that is required to fuel breeder reactors. In this paper, we demonstrate that this methodology is problematic, in particular that it would result in negative balances of plutonium if the DAE's projections were to come true. The DAE's projections also ignore constraints coming from reprocessing capacity in the country. As an alternative, we project the possible growth of nuclear power based on breeder reactors using a methodology consistent with plutonium constraints. The resulting breeder reactor capacity will be only between 17% and 40% of the DAE's projections, and will likely never constitute a major source of electricity in India for several decades at the very least.     

Effects of technological learning and uranium price on nuclear cost: Preliminary insights from a multiple factors learning curve and uranium market modeling

This paper studies the effects of returns to scale, technological learning, i.e. learning-by-doing and learning-by-searching, and uranium price on the prospects of nuclear cost decrease. We use an extended learning curve specification, named multiple factors learning curve (MFLC). In a first stage, we estimate a single MFLC. In a second stage, we estimate the MFLC under the framework of simultaneous system of equations which takes into account the uranium supply and demand. This permits not only to enhance the reliability of the estimation by incorporating the uranium price formation mechanisms in the MFLC via the price variable, but also to give preliminary insights about uranium supply and demand behaviors and the associated effects on the nuclear expansion.Results point out that the nuclear cost has important prospects for decrease via capacity expansion, i.e. learning-by-doing effects. In contrast, they show that the learning-by-searching as well as the scale effects have a limited effect on the cost decrease prospects. Conversely, results also show that uranium price exerts a positive and significant effect on nuclear cost, implying that when the uranium price increases, the nuclear power generation cost decreases. Since uranium is characterized by important physical availability, and since it represents only a minor part in the total nuclear cost, we consider that in a context of increasing demand for nuclear energy the latter result can be explained by the fact that the positive learning effects on the cost of nuclear act in a way to dissipate the negative ones that an increase in uranium price may exert. Further, results give evidence of important inertia in the supply and demand sides as well as evidence of slow correlation between the uranium market and oil market which may limit the inter-fuels substituability effects, that is, nuclear capacity expansion and associated learning-by-doing benefits.     

ARIMA forecasting of China’s coal consumption,price and investment by 2030

Forecasting of energy consumption, price, and investment in coal industry is one of the most important proactive approaches and policy instruments used by decision-makers in China. Due to the richer information on time-related changes than the other methods, autoregressive integrated moving average (ARIMA) is applied to estimate the further coal price, consumption, and investment of China from 2016 to 2030. The best-fitted models for coal price, consumption, and investment at each predicted step are selected. The empirical results show that the annual average rate of coal consumption and investment will decrease between 2016 and 2030 except for coal price, which exhibits fluctuant behavior in the forecast period. The annual droop rate of coal consumption from 2016 to 2030 will be rather big, nearly the same with the annual growth rate from 2000 to 2015. The coal investment has the similar result with coal consumption.     

Biomass and CCS: The influence of technical change

The combination of bioenergy production and carbon capture and storage technologies (BECCS) provides an opportunity to create negative emissions of CO₂ in biofuel production. However, high capture costs reduce profitability. This paper investigates carbon price uncertainty and technological uncertainty through a real option approach. We compare the cases of early and delayed CCS deployments. An early technological progress may arise from aggressive R&D and pilot project programs, but the expected cost reduction remains uncertain. We show that this approach results in lower emissions and more rapid investment returns although these returns will not fully materialise until after 2030. In a second set of simulations, we apply an incentive that prioritises sequestered emissions rather than avoided emissions. In other words, this economic instrument does not account for CO₂ emissions from the CCS implementation itself, but rewards all the sequestered emissions. In contrast with technological innovations, this subsidy is certain for the investor. The resulting investment level is higher, and the project may become profitable before 2030. Negative emission in bioethanol production does not seem to be a short-term solution in our framework, whatever the carbon price drift.