Nuclear energy SAVES lives – on a grand scale!

In a recent paper [1], Pushker Kharecha and James Hansen presented calculations that the use of nuclear power has already prevented almost two million deaths:

“Because nuclear power is an abundant, low-carbon source of base-load power, it could make a large contribution to mitigation of global climate change and air pollution. Using historical production data, we calculate that global nuclear power has prevented an average of 1.84 million air pollution-related deaths and 64 gigatonnes of CO2-equivalent (GtCO2-eq) greenhouse gas (GHG) emissions that would have resulted from fossil fuel burning. On the basis of global projection data that take into account the effects of the Fukushima accident, we find that nuclear power could additionally prevent an average of 420,000-7.04 million deaths and 80–240 GtCO2-eq emissions due to fossil fuels by midcentury, depending on which fuel it replaces.”

“In Germany, which has announced plans to shut down all reactors by 2022, we calculate that nuclear power has prevented an average of over 117,000 deaths from 1971-2009.”

[1] Kharecha, P.A., and J.E. Hansen, 2013: “Prevented mortality and greenhouse gas emissions from historical and projected nuclear power,” Environ. Sci. Technol., 47, 4889-4895, doi:10.1021/es3051197.

Abstract and links:

http://pubs.giss.nasa.gov/abs/kh05000e.html

Full paper:

http://pubs.giss.nasa.gov/docs/notyet/inpress_Kharecha_Hansen.pdf

Kharecha and Hansen Call For Expansion of Nuclear Power

In a recent paper [1], Pushker Kharecha and James Hansen called for “expanding the role of nuclear power” as a clear necessity in order to avoid “devastating climate impacts” from greenhouse gases:

“…it is clear that nuclear power has provided a large contribution to the reduction of global mortality and GHG emissions due to fossil fuel use. If the role of nuclear power significantly declines in the next few decades, the International Energy Agency asserts that achieving a target atmospheric GHG level of 450 ppm CO2-eq would require ‘heroic achievements in the deployment of emerging low-carbon technologies, which have yet to be proven. Countries that rely heavily on nuclear power would find it particularly challenging and significantly more costly to meet their targeted levels of emissions.’ Our analysis herein and a prior one strongly support this conclusion. Indeed, on the basis of combined evidence from paleoclimate data, observed ongoing climate impacts, and the measured planetary energy imbalance, it appears increasingly clear that the commonly discussed targets of 450 ppm and 2° C global temperature rise (above preindustrial levels) are insufficient to avoid devastating climate impacts; we have suggested elsewhere that more appropriate targets are less than 350 ppm and 1°C (refs 3 and 31−33). Aiming for these targets emphasizes the importance of retaining and expanding the role of nuclear power, as well as energy efficiency improvements and renewables, in the near-term global energy supply.”

[1] Kharecha, P.A., and J.E. Hansen, 2013: “Prevented mortality and greenhouse gas emissions from historical and projected nuclear power.” Environ. Sci. Technol., 47, 4889-4895, doi:10.1021/es3051197.

Abstract and links:

http://pubs.giss.nasa.gov/abs/kh05000e.html

Full paper:

http://pubs.giss.nasa.gov/docs/notyet/inpress_Kharecha_Hansen.pdf

FS-MSR Deterministic Safety, As Seen By ORNL

The great advantages of FS-MSRs with regard to operational safety form a very important but complex topic, which remains to elucidated in detail. As a starting point, and in honor of Oak Ridge National Laboratory (ORNL), we here provide some concise excerpts on this subject from ORNL’s recent paper, “Fast Spectrum Molten Salt Reactor Options.” [1]

First, let’s have a look at some of ORNL’s introductory notes on the FS-MSR:

“The unique characteristic of MSRs is the use of a liquid fuel rather than the solid fuels used in more conventional designs. Halide salts have been demonstrated to provide a high degree of solubility of actinides in concentrations sufficient to maintain a critical system. The use of liquid fuel enables many design options and fuel cycle opportunities that are not possible with solid fuel. Liquid-fueled reactors eliminate fuel or target fabrication, which presents technical challenges when using actinide and/or TRU fuel and can result in the need for capital-intensive facilities. In the MSR, each batch of fuel that is fed into the reactor is blended into the existing fuel inventory; consequently, the addition of fuel has a limited impact on the isotopic composition of the fuel so that no need exists to control the variability of the isotopic concentration of the feed fuel. The fuel feed can be in solid or liquid form.

“An FS-MSR fuel cycle consists of a fast-spectrum molten salt core, a heat removal and power conversion system, and a salt processing and cleanup system. The reactor can be designed to have a range of heavy metal conversion ratios so that it serves waste management functions (with a low conversion ratio) or fuel cycle sustainability functions (with a high conversion ratio, unity or greater). For the waste management function, the system would be configured with a front-end processing system for used fuel, like the ones used in LWRs; whereas for the sustainability mission, after an initial charge of fissile material, the feed material could consist of natural or depleted uranium or thorium. For a waste management reactor, the front-end processing system could be located onsite or the used LWR fuel could be processed at a central facility supporting several reactors. For the on-site reprocessing option, once the used LWR fuel is brought into salt form and the excess uranium is removed, the processing steps are identical to those for the FS-MSR’s used fuel salt. Hence much of the infrastructure can do double duty, removing fission products from both used LWR fuel and FS-MSR fuel salt.

“The safety aspects of FS-MSRs are also innovative. FS-MSRs have a negative salt void coefficient (expanded fuel is pushed out of the core) and negative thermal reactivity feedback that avoids a set of major design constraints in solid-fuel fast reactors. A passive core drain system activated by a melt plug enables draining the radioactive inventory into geometrically subcritical drain tanks that are passively thermally coupled to the environment. FS-MSRs have a low operating pressure even at high temperatures. The fuel/coolant is transparent, allowing visual inspection, and methods of maintenance for the system have been conceptually developed based on the MSRE experience. The high-temperature operation of the reactor is compatible with process heat applications and can be coupled to high-efficiency power conversion systems for electricity production.”

And now, the promised excerpts regarding safety:

“FS-MSRs have the potential for incorporating excellent passive safety characteristics. They have a negative salt void coefficient (expanded fuel is pushed out of the core) and a negative thermal reactivity feedback that avoids a set of major design constraints in solid-fuel fast reactors. Thus, an FS-MSR can provide a high power density while maintaining passive safety. The liquid state of the core also enables a passive, thermally triggered (melt plug) core draining into geometrically subcritical tanks that are passively thermally coupled to the environment. FS-MSRs have a low operating pressure even at high temperatures, and FS-MSR salts are chemically inert, thermodynamically lacking the energetic reactions with environmental materials seen in other reactor types (e.g., hot zirconium or sodium with water).”

“FS-MSRs can provide a high degree of passive nuclear safety while enabling fissile resource extension, maintaining high power output, and achieving high power density. This set of characteristics compares favorably with all other proposed reactor classes. The high degree of negative thermal reactivity feedback due to the large fuel salt coefficient of thermal expansion combined with the negative void reactivity feedback is a unique reactor characteristic. Also, the ability to passively drain the core into geometrically subcritical decay tanks that provide for passive decay heat removal (likely via heat pipes to the surrounding soil) provides a highly robust severe-accident response that compares favorably with the capabilities of solid-fuel reactors.”

“FS-MSRs have the potential for excellent passive safety characteristics. FS-MSRs have a negative salt void coefficient (expanded fuel is pushed out of the core) and a negative thermal reactivity feedback that avoids a set of major design constraints in solid-fuel fast reactors. A passive core drain system activated by a melt plug enables draining the radioactive inventory into geometrically subcritical drain tanks that are passively thermally coupled to the environment. FS-MSRs have a low operating pressure even at high temperatures; and FS-MSR salts are chemically inert, thermodynamically lacking the energetic reactions with environmental materials seen in other reactor types (hot zirconium and sodium with water). FS-MSRs do involve more intensive manipulation of highly radioactive materials than other reactor classes and thus small spills and contamination accidents appear to be more likely with this reactor class.”

REFERENCES

[1] D.E. Holcomb et al, “Fast Spectrum Molten Salt Reactor Options,” OAK RIDGE NATIONAL LABORATORY, July 2011, http://info.ornl.gov/sites/publications/files/Pub29596.pdf

Three Swap-outs To Save The World

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In order to avoid a climate change catastrophe, we need to dramatically reduce CO2 emissions worldwide. This gives us three basic tasks:

1) Phase out fossil-fueled power plants.

2) Phase out gasoline- and diesel-fueled cars and trucks.

3) Phase out diesel-powered container ships.

The good news is that all of these tasks can be accomplished, if we set our minds to it. Here’s how:

1) Complete the development of the safe and affordable Fast Spectrum Molten Salt Reactor (FS-MSR), also known as the Molten Salt Fast Reactor (MSFR), and deploy them in place of fossil-fueled power plants.

http://info.ornl.gov/sites/publications/files/Pub29596.pdf

http://hal.in2p3.fr/docs/00/18/69/44/PDF/TMSR-ENC07.pdf

http://www.tnw.tudelft.nl/fileadmin/Faculteit/TNW/Over_de_faculteit/Afdelingen/Radiation_Radionuclides_Reactors/Research/Research_Groups/NERA/Publications/doc/MSc_Erik_van_der_Linden.pdf

Here is an excellent and very recent detailed evaluation of the MSFR and its advantages:

https://www.politesi.polimi.it/bitstream/10589/74324/1/2013_03_PhD_Fiorina.pdf

FS-MSRs use molten salt coolant at a temperature that happens to be useful to supply the heat for Solid State Ammonia Synthesizer (SSAS) units. FS-MSRs can be fitted with these units to synthesize ammonia in a carbon-free process.

2) Replace or refit cars and trucks with ammonia-powered engines. Ammonia filling stations will provide the vehicles with ammonia produced by carbon-free solid state synthesis.

http://nh3fuelassociation.org/

http://nhthree.com/ssas.html

3) Replace container ship diesel engines with safe advanced nuclear engines.

http://www.janleenkloosterman.nl/reports/thesis_jacobs_2007.pdf

http://canes.mit.edu/content/nuclear-power-container-ships

Book Review: “Multi-Physics Approach to the Modeling and Analysis of Molten Salt Reactors,” by Luzzi, Di Marcello and Cammi

This short but excellent book, published in 2012, mostly addresses its subject at a level useful to engineers, and presents mathematical analyses of heat transfer, thermo-hydrodynamics and neutronics in a graphite-moderated molten salt reactor, such as the Molten Salt Breeder Reactor (MSBR) designed at Oak Ridge National Laboratory.

The book reflects at least two basic aims. One is to analyse the MSBR. The other is to explicate what the authors term “multi-physics modeling” (MPM) strategy, in the expectation that MPM will be used to analyse other MSRs, such as the Molten Salt Fast Reactor (MSFR). (Indeed, MPM studies of the MSFR have been recently published.)

The first chapter provides an excellent overview of molten salt reactor technology, including not only the thermal-spectrum MSBR, but also fast-spectrum breeder reactors, fast-spectrum incinerator reactors, and others. The extensive list of references is another great feature of this book.

Let’s see what the authors have to say about the Molten Salt Fast Reactor (MSFR):

“Based on the TMSR concept and on extensive parametric studies in which various core arrangements, reprocessing performances and fuel salt compositions were investigated, an innovative Th-U MSFR… has been recently proposed and is currently under development of the EVOL (Evaluation and Viability of Liquid Fuel Fast Reactor Systems) Euratom Project (Renault et al., 2010). The MSFR can operate with widely varying fuel composition. Thanks to this fuel composition flexibilty, this reactor may use, as initial fissile load, 233U or the transuranic (TRU) elements currently produced by PWRs in the world. In terms of the fuel cycle, two basic options have been mainly investigated, i.e.: the 233U-started MSFR and the TRU-started MSFR… Last, but not least, the level of deterministic safety reached in both starting modes is excellent since the feedback loops are negative. Further information on the Th-U MSFR can be found in (Renault et al., 2010).”

The EVOL Project

Evaluation and Viability of Liquid Fuel Fast Reactor System

Objective: An innovative molten salt reactor concept, the MSFR (Molten Salt Fast Reactor) is developed by CNRS (France) since 2004. Based on the particularity of using a liquid fuel, this concept is derived from the American molten salt reactors (included the demonstrator MSRE) developed in the 1960s. The major drawbacks of these designs were (1) a short lifetime of the graphite blocks, (2) a reactor fuelled with 233U, not a natural fissile isotope, (3) a salt constituted of a high chemical toxic element: BeF2, and (4) a fuel reprocessing flux of 4000 liters per day required reaching a high breeding gain. However, this concept is retained by the Generation IV initiative, taking advantages of using a liquid fuel which allows more manageable on-line core control and reprocessing, fuel cycle flexibility (U or Th) and minimization of radiotoxic nuclear wastes. In MSFR, MSR concept has been revisited by removing graphite and BeF2. The neutron spectrum is fast and the reprocessing rate strongly reduced down to 40 litters per day to get a positive breeding gain. The reactor is started with 233U or with a Pu and minor actinides (MA) mixture from PWR spent fuel. The MA consumption with burn-up demonstrates the burner capability of MSFR.

The objective of this project is to propose a design of MSFR in 2012 given the best system configuration issued from physical, chemical and material studies, for the reactor core, the reprocessing unit and the wastes conditioning. By this way, demonstration that MSFR can satisfy the goals of Gen IV, in terms of sustainability (Th breeder), non proliferation (integrated fuel cycle, multi-recycling of actinides), resources (close U/Th fuel cycle, no uranium enrichment), safety (no reactivity reserve, strongly negative feedback coefficient) and waste management (actinide burner) will be done

http://cordis.europa.eu/search/index.cfm?fuseaction=proj.document&PJ_RCN=11669355

Recent Research Modelling Molten Salt Fast Reactors

An approach to the MSR dynamics and stability analysis

Claudia Guerrieri, Antonio Cammi, Lelio Luzzi

March 2013

Abstract

The first efforts in the development of the molten salt reactor technology were carried out in the sixties by the Oak Ridge National Laboratory and culminated with the design of the thermal-spectrum Molten Salt Breeder Reactor (MSBR). Only recently, the attention has been focused on fast-spectrum configurations, such as the Molten Salt Fast Reactor (MSFR) proposed in the framework of the Euratom EVOL (Evaluation and Viability of Liquid Fuel Fast Reactor System) Project, thanks to their favourable characteristics in terms of sustainability, waste minimization and improved safety. As a matter of fact, the MSFR has been recognized as a long term alternative to solid-fuelled fast neutron systems and has been identified as Gen-IV reference MSR configuration. From the dynamic behaviour point of view, the main feature that characterises this kind of systems is the presence of a liquid fuel that circulates in the primary circuit acting simultaneously as coolant. This feature leads to a complex and highly coupled behaviour, which requires a careful investigation, due to some peculiarities like the drift of delayed neutron precursors along the primary circuit. Although considerable studies have been carried out for the analysis of the graphite-moderated MSRs, the adoption of a fast spectrum configuration without graphite in the core is expected to notably modify the dynamic characteristics of the system, thus requiring further investigation. This work proposes an approach to the dynamics and stability analysis of molten salt reactors. In particular, the well-developed methods of the theory of linear systems are applied to the analysis of two case studies, namely: the MSBR and the recently proposed MSFR. This analysis is intended to provide a basic understanding of the inherent stability properties and of the dynamic characteristics of such kind of nuclear reactors, highlighting the main peculiarities of the new design compared with the more familiar graphite-moderated concept.

http://www.sciencedirect.com/science/article/pii/S0149197013000656

The Molten Salt Fast Reactor as a Fast-Spectrum Candidate for Thorium Implementation

Carlo Fiorina
March, 2013

https://www.politesi.polimi.it/bitstream/10589/74324/1/2013_03_PhD_Fiorina.pdf

Coupled neutronics and computational fluid dynamics for the molten salt fast reactorFeaturing a physical description of the precursor transport in liquid turbulent nuclear fuels

E. van der Linden
April 2012

http://www.tnw.tudelft.nl/fileadmin/Faculteit/TNW/Over_de_faculteit/Afdelingen/Radiation_Radionuclides_Reactors/Research/Research_Groups/NERA/Publications/doc/MSc_Erik_van_der_Linden.pdf

Fast Thorium Molten Salt Reactors Started with Plutonium

E. Merle-Lucotte, D. Heuer, C. Le Brun, L. Mathieu, R. Brissot, E. Liatard, O. Meplan, A. Nuttin
June 2006

http://hal.inria.fr/docs/00/13/51/41/PDF/ICAPP06_TMSR.pdf

Molten Salt Fast Reactors: The Key To Clear Skies

We are faced with an urgent humanitarian need to stop burning coal. Coal soot not only shortens hundreds of thousands of lives worldwide, it also causes impaired development and permanent damage to tens of thousands of children. To end this suffering and tragic loss of potential, we need to make available to all countries a safe and carbon-free alternative to coal power, that would be cheaper than coal power.

We can state with certainty that “renewables” can never replace coal and natural gas worldwide, while still allowing underdeveloped countries to improve their standard of living.

Wind turbines and solar cells provide low-quality, unreliable, non-dispatchable power, that does not meet the needs of power providers. Therefore they hardly reduce the non-wind, non-solar plant that must be built. In fact in practice they significantly reduce the efficiency of any fossil-fuel backup sources, resulting in negligible emissions reductions. They offer low-quality power at an ultimate high cost, when the need for backup power is considered. Any attempt to improve the quality by resorting to storage batteries will make the cost exorbitant, due to inefficiency of storage.

The safe and affordable nuclear power that could be produced by utilizing a thorium fuel cycle in a Molten Salt Fast Reactor clearly offers the best available prospect of phasing out fossil-fuel plants worldwide, while still allowing all countries to improve their standard of living.

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