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Communicating Scientific Evidence to Someone with a View Contrary to Yours: Respecting Cultural Values

S.W. Pierson

Not accepting your scientific evidence ≠ not appreciating science

As scientists, we like to think the scientific evidence we present will be readily accepted, particularly when it is the consensus or established view. Having worked the past 15 years for a scientific society — six years in the APS Physics Washington Office under the expert guidance of Michael Lubell and Francis Slakey and almost nine years with the American Statistical Association — it is particularly disappointing when the scientific position of such a society isn’t accepted as valid. After all, the position of a science society necessarily represents a balanced view of the science. For years I struggled to grapple with this reticence to accept a scientific society’s position as authoritative. A 2010 paper in Nature magazine — Fixing the Communications Failure by Dan Kahan of the Yale Law School — provided to me by a Capitol Hill staffer helped me to better understand the phenomena and how to try to address it.

In this piece, I will discuss this work of Kahan and his colleagues because I think it is so insightful and — even seven years after its publication — is not as well known as I think it should be. I will also mention some of Kahan’s subsequent work and possible ramifications for scientific societies and scientists on current topics.

Kahan et al. Cultural Cognition Work

Kahan’s central point in his 2010 article is that how people receive scientific information depends upon their cultural values, a process they call cultural cognition. Their work seems to hold over a variety of topics — from the safety of nuclear waste storage and climate change to nanotechnology and vaccines — and is symmetric by cultural group (which I’ll explain more below.) To frame his discussion, Kahan starts his article recapping a 1950’s psychology experiment in which students from separate universities are asked to assess the referee calls of a football game between their two universities. Not surprisingly, how students viewed a controversial call depended to a great extent on whether the call benefitted or hurt their team.

In the context of scientific debates, Kahan and coworkers identify two groups: (i) "People with individualistic values, who prize personal initiative, and those with hierarchical values, who respect authority, tend to dismiss evidence of environmental risks, because the widespread acceptance of such evidence would lead to restrictions on commerce and industry, activities they admire"; (ii) "people who subscribe to more egalitarian and communitarian values are suspicious of commerce and industry, which they see as sources of unjust disparity. They are thus more inclined to believe that such activities pose unacceptable risks and should be restricted."

A key finding of their work is that "groups with opposing values often become more polarized, not less, when exposed to scientifically sound information." Yes, you read that correctly: providing scientific evidence contrary to a person’s standing can be counter productive. Before any of us jump too soon to conclusions about being above this phenomenon, Kahan’s group found this to be true not only for the egalitarian/communitarian group when it comes to nuclear waste but also the hierarchical individualistic group when it comes to anthropogenic climate change.

Kahan provides a couple recommendations for how scientists can deal with a limitation of not being able to lead with or even emphasize the science. Building on the work of Stanford Psychologist Geoffrey Cohen, one approach is "to present information in a manner that affirms rather than threatens people’s values." "For instance," Kahan writes, people with individualistic values resist scientific evidence that climate change is a serious threat because they have come to assume that industry-constraining carbon-emission limits are the main solution. They would probably look at the evidence more favourably, however, if made aware that the possible responses to climate change include nuclear power and geoengineering, enterprises that to them symbolize human resourcefulness. Similarly, people with an egalitarian outlooks are less likely to reflexively dismiss evidence of the safety of nanotechnology if they are made aware of the part that nanotechnology might play in environmental protection, and not just its usefulness in the manufacture of consumer goods.

Kahan continues, "The second technique for mitigating public conflict over scientific evidence is to make sure that sound information is vouched for by a diverse set of experts."

Implications for Kahan’s work for Scientists and Scientific Societies

The work of Kahan and many others doing science communications research on how people receive scientific information provides many insights that we can use and learn from. An obvious one is not to assume people holding a view contrary to ours do not appreciate science. In retrospect, I saw this firsthand as a guest to a black-tie celebration of a libertarian think tank’s anniversary. The honored guest was Norman Borlaug, the late plant geneticist whose work in bringing high-yield wheat varieties — along with improved agricultural production techniques — vastly improved the food security of countries like India, Mexico, and Pakistan. While praising Borlaug’s scientific advances, the group roasted the scientific work of climate researchers. (For full disclosure, I believe I am more of an egalitarian/communitarian thinker and hold the view of the APS statement "Earth’s Changing Climate", i.e., it "is a critical issue and poses the risk of significant environmental, social and economic disruptions around the globe… multiple lines of evidence indicate that human influences have had an increasingly dominant effect on global climate. The potential consequences of climate change are great and the actions taken over the next few decades will determine human influences on the climate for centuries. ") At the time, I felt the group was trying to have it two ways, praising some scientific work and rejecting other scientific evidence. Looking at the apparent pick-and-choose approach through the lens of Kahan’s work, Borlaug’s scientific accomplishments resonate with the hierarchical individualist themes of technological advances that contribute to commerce and industry—as opposed to restricting it — while addressing aglobal challenge. For climate change, I believe the group saw — and perhaps still do — steps to address climate change as being more restrictive of commerce and industry.

I also value Kahan’s advice to take the approach of affirming — rather than threatening — people’s values when discussing the scientific evidence relevant to issues of the day. Implicit in this I believe is establishing a relationship to learn each other’s values. This will take time but, as Kahan also says in his Nature article, "citizens who hold opposing cultural outlooks are in fact rooting for the same outcome: the health, safety and economic well-being of their society." A December 2015 Washington Post article — Their 1996 clash shaped the gun debate for years. Now they want to reshape it — is a fascinating example of this. The article tells the story of the Arkansas Congressman whose 1996 clash with a Center for Disease Control (CDC) gun violence researcher led to the CDC’s decision to stop its gun-violence research. A few weeks later after their tense encounter, Congressman Jay Dickey (R-Ark.) had his staff invite Dr. Mark Rosenberg into his office to review some data. After meeting with staff, Dr. Rosenberg was invited to speak with the congressman. Saying in the 2015 Post piece that he "knew the value of not letting divisions exist," Congressman Dickey didn’t talk about gun violence research that day. Instead the two talked about their children and other such topics. A friendship ensued and it was only after they became trusted friends that they could talk about gun violence. Sixteen years later, in 2012, they coauthored an op-ed in the Washington Post saying they are "are in strong agreement now that scientific research should be conducted into preventing firearm injuries and that ways to prevent firearm deaths can be found without encroaching on the rights of legitimate gun owners."

The circumstances leading to the Dickey-Rosenberg friendship are quite different than meetings scientists request with Members of Congress or their staff to discuss climate change. We can’t wait for the Member or staffer to ask us about our children but must make the most of their limited time and to get to our point quickly. Nevertheless, I believe such meetings are constructive when their purpose is to start or continue the conversation (preferably with the Member) and to develop rapport and trust. Annually for six years I have accompanied Leonard Smith (London School of Economicsand Pembroke College, Oxford) — who is both a member of the ASA and the APS — into his Republican U.S. Representative’s office to talk about climate science. Through three different staffers and mixed reactions (from skeptical to indifferent) to the discussions of wilderness, residential, commercial, and military areas in the district threatened by climate and/or sea level rise, we were gratified — not to mention pleasantly surprised — when this year they said they’d be willing to consider cosponsoring the "Gibson Resolution", a non-binding House Resolution (H.Res. 424) on environmental stewardship that acknowledges a "changing climate" and it being a "conservative principle to protect, conserve, and be good stewards of our environment."Only an anecdote of a small victory to be sure but it demonstrates the potential of regularly and earnestly engaging and listening to policymakers on topics we may not agree. It also leads one to ask what could be achieved through a more concerted and organized long-term effort to have scientists working to build trusting relationships with their policymakers.

In my lead paragraph I say scientific societies must necessarily present a balanced view of the science of a given topic. I believe this because scientific societies represent scientists holding a broad range of views on a given scientific topic. To take the diverse views of its members into account when developing their position statements, I have only seen societies present a balanced view of the membership of its societies. Further, because it is imperative scientific societies protect their reputations as objective entities, I believe scientific societies tend to be conservative in presenting what they see as the scientific position.

With our unique capability to present a balanced view on a scientific topic, scientific societies have an important role to play in informing policymaking and the public on matters of national importance. The APS is a leader in this regard through its "POPA Reports", the in-depth studies on topics ranging from energy and environment to national security issues from the Panel on Public Affairs (POPA). Indeed, I think the experts assembled for the POPA reports embody Kahan’s second suggestion that sound information be vouched for by a diverse set of experts.

In addition to more societies issuing such reports and perhaps issuing joint reports (the ASA would be pleased to suggest statisticians for future POPA reports), we must educate policymakers and the public about the scientific authority we bring to a topic. Last year I was with representatives of two other scientific bodies in a meeting with a Senate committee staffer that was likely a case of us trying to present a scientific view contrary to the staffer’s position. After our best efforts of presenting the science, her reply was that she had a letter signed by 78 scientists supporting her position. I tried to explain our view represented the middle of a bell-curve of scientific views while her 78 were on one of the extremes but I knew we had lost the day with no trust or rapport on which to go. (Professor Smith and I were also told early in our six annual visits by a congressional staffer that, when it comes to climate change, "we have our experts and you have your experts" reinforcing their appreciation for science but illustrating the large divide on the topic.) I maintain however that it comes back to scientific societies also building and maintaining the trusting relationships I suggested earlier for individual scientists.

By stressing the balanced view that we can present from a bell-curve of scientific judgements, scientific societies can counteract the often slanted view a congressional panel too often presents on a heated topic. With the minority only usually allowed one witness and the majority the rest, it has been my observationthe last couple years that hearings on climate change have not presented a balanced view on climate change, largely due to the majority witnesses being mostly from one of the extremes. While I understand that hearings in non-science committeeswill take more political positions, I believe the science committees have a responsibility to the American people to present a more balanced view on a topic as important as climate change.

While progress on climate change — as characterized by bipartisan recognition of the problem and bipartisan resolve to address it — will beslow and consensus is lacking about how to achieve such progress, I would be happy with the small step of bipartisan acknowledgement that the changing climate is a problem and that humans are a primary cause. Perhaps to achieve or at least gauge such bipartisan agreement, Democrats in recent years have offered "Sense of Congress" amendments saying, in effect, climate change is occurring and humans are the primary driver. During a January, 2015 Senate debate on the Keystone XL pipeline, five Republicans voted to support an amendment saying "climate change is real" and that "human activity significantly contributes to climate change". (As an aside but informative of the political dynamics, two of the five Republican Senators lost their reelection bids in November: Senator Mark Kirk of Illinois and Senator Kelly Ayotte of New Hampshire.) In the House science committee later that winter, a similar amendment was amended to remove the line about humans being the primary cause and then passed.

I have not followed Kahan’s work closely since his 2010 Nature paper but did see a May 2015 presentation where a theme was, "Don’t make reasoning, free people choose between knowing what’s known and being who they are." Applying this to the "Sense-of-Congress" efforts, it seems like Democrats are trying to force Republicans to choose between knowing what’s known and being true to their constituents. After all, one of the factors identified in the 2010 primary loss of South Carolina’s Republican U.S. Representative Bob Inglis was his acknowledgement that climate change is caused by human activities and poses significant risks. As a thought experiment, what if the Sense of Congress were to read as follows?

It is the sense of Congress that the overwhelming majority of scientists with expertise in climate science agree that —

(1) climate change is occurring; and

(2) human activity significantly contributes to climate change.

By inserting "the overwhelming majority of scientists with expertise in climate science agree that", the languageis no longer asking Members of Congress to say what they believe regarding anthropogenic climate change per se but is asking them to acknowledge where the majority of scientists and scientific societies are regarding anthropogenic climate change.

Whether or not a vote on such a "Sense of Congress" would move the ball forward in some small way I’ll leave to others. Regardless, it’s imperative we listen to what science communication researchers are telling us and merely impose our scientific knowledge upon policymakers and the public.

Steve W. Pierson

spierson@amstat.org

Small Modular Reactors and the Challenges of Nuclear Power

M.V. Ramana and Zia Mian, Princeton University

Nuclear energy is on the decline, certainly as a share of global electricity generation. Between 1996 and 2016, this share has come down from 17.6 percent to 10.7 percent (BP 2016). Future prospects don’t seem any better either: the International Atomic Energy Agency’s projections for 2030 and 2050 see nuclear energy maintaining market share under the high scenarios, and declining under low scenarios (Ramana 2016a).

The influential 2003 study on the future of nuclear power from the Massachusetts Institute of Technology attributed the "limited prospects for nuclear power" to "four unresolved problems": costs of generating electricity at nuclear reactors, safety of reactors and nuclear fuel cycle facilities; proliferation and the possible misuse of commercial or associated nuclear facilities and operations to acquire technology or materials as a precursor to the acquisition of a nuclear weapons capability"; and "unresolved challenges in long-term management of radioactive wastes" (Deutch et al. 2003, 2).

One particular problem that has become even more of a challenge in the last decade or more has been increasing costs of construction. Reactors classified as Generation III or III+ have typically costed 6 to 10 billion dollars (for 1100 to 1600 MW of generating capacity), and have taken close to a decade or more to construct; practically all have experienced time and cost overruns in comparison with initial estimates (Schneider and Froggatt 2015). In response, nuclear reactor developers and vendors in several countries have been pursuing the development of Small Modular Reactors (SMRs), with power levels between 10 and 300 MWe, much smaller than the 1000–1600 MWe reactor designs that have become the industry standard.

Proponents of SMRs suggest that these reactors can resolve the four key challenges confronting nuclear power today. In turn, many countries, including the United States, Russia, China, France, Japan, South Korea, India, and Argentina, are investing large amounts of money to support such development. What are the prospects of SMRs solving the problems confronting nuclear power?

Any attempt to deal with the problems identified above — safety enhancement, proliferation resistance, decreased generation of waste, and cost reduction — has to be reflected in some fashion in the design of specific nuclear reactors. But it turns out that each of these priorities can drive the requirements on the reactor design in different, sometimes opposing, directions (Ramana and Mian 2014). Leading SMR designs under development involve choices and trade-offs between desired features and focusing on any one goal might make other goals more difficult to achieve.

Because there a number of SMR designs are under development, it is not possible to examine each of them to demonstrate these trade-offs. SMR designs vary by power output, physical size, fuel geometry, fuel type and enrichment level (and resulting spent fuel isotopic composition), refueling frequency, site location, and status of development. However, the many different kinds of SMRs can be classified into a few families, which share common characteristics.

For the complete article, view the full newsletter.

Fission and Fusion: A Path to Energy Security

Dr. John A. Parmentola and Dr. Charles E. Kessel

In a recent Forum article (October 2016) Dr. Jassby identifies seven technical issues that a commercial fission and a future fusion reactor have in common. The theme of his argument is that as a result of these issues commercial fission is failing in the energy marketplace, and because these issues are shared it is likely that fusion will also fail.

Why is Fission Becoming Less Competitive?

Fission reactors have been adversely affected by the dramatic drop in the price of natural gas, largely due to fracking. The relatively low-risk premium for the financing and building of natural gas power plants, the very high efficiency of combined cycle natural gas plants (63%), and the substantial subsidies and government priorities afforded to electricity produced by renewables, have reduced the competitiveness of nuclear power. Fission has also relied on a technology whose efficiency (33%) has not changed over 60 years. Its demise is in large part a result of incremental improvements on 60-year-old concept and a poor investment strategy to improve its performance.

Advanced Fission Reactor Initiatives

The goals of advanced fission concepts are to reduce the price of electricity, improve safety, reduce waste production and increase proliferation resistance. The vast majority of advanced fission reactor concepts involve higher operating temperatures, as high as 850 C, higher thermal conversion efficiencies, and fuel burnups 3 times that of current reactors. Research on new high temperature and radiation resistant materials, such as ceramic materials, for cladding, heat exchangers, and vessels, can have significant impacts on conversion efficiency, fuel burnup, safety margins, and waste production. Other concepts involve different coolants to increase operating temperatures, and still others offer unique core designs that enable higher fuel burnups[1]. To reduce the risk premium of fission reactors, there are now several modular designs that allow manufacturing and assembly at a factory and then shipment by ground or barge to a reactor site for installation. Much of this is also relevant to the future of fusion reactors.

Why Do We Need Fission and Fusion?

Abundant supplies of low cost energy are critical to coping with the challenges of world population growth and the demands that will be placed on a broad range of resources such water, food, materials, healthcare, communications, and transportation. The world cannot grow and the quality of life improved without abundant, affordable and reliable amounts of energy.

Utilities, taking advantage of the low costs of natural gas, are replacing aging coal plants at a higher than expected rate, resulting in electricity production from natural gas now surpassing coal. This will very likely continue as long as future government policies do not adversely affect the natural gas industry or the price of natural gas does not significantly increase.

If you now add to this, the aging of approximately 100 U.S. fission power plants, whose licenses are scheduled to end on a timetable from now until 2050, natural gas is again the likely replacement option.

The elimination of coal and fission plants amounts to a 53% reduction in our current total national electricity production. If electricity demand increased by just 1% per year from now to 2050, then that would require an additional increase in electricity production capacity by over 40%.

From now until 2050 the gradual shortfall of electricity capacity, whether 53% or 90% or if demand increases significantly, would have to come from only two sources, natural gas, which is an exhaustible resource, and renewables, which have significant scalability and operating capacity issues given the potential magnitude of the shortfall. This is not a viable energy security strategy for a major economic power like the U.S., because it could make our nation dependent upon others for our energy needs.

There are two scalable clean-energy options to consider, namely fission and fusion power. Nuclear fission and fusion power both have a common strategic advantage, large fuel reserves. For properly designed advanced nuclear reactors, proven uranium reserves (those reserves that today can be affordably extracted from the earth) have enough energy content to last the entire world well over 10,000 years based upon total world electricity consumption per year. Unfortunately, current nuclear reactors severely under-utilize the usable energy out of uranium fuel, which contributes to the larger nuclear waste volume.

For fusion energy, lithium is the key energy resource, which based upon proven reserves, could last well over 20,000 years assuming the same world electricity consumption rate per year. Such enormous amounts of energy do not include all known reserves of uranium and lithium, such as those that today are not economically extractable in the oceans.

Comments on Jassby’s Points

1) Radiation damage imperils reactor integrity.

The only accessible fusion nuclear reaction is the combination of deuterium (D) and tritium (T) to produce a neutron and a helium nucleus, because there are ways to confine plasmas and heat them so that they generate thousands of mega-watts of energy to ultimately convert heat into electricity. For the D + T reaction, the neutrons stream out of the hot plasma and into the surrounding structures, heating them and providing the dominant part of the energy to make electricity. The differences between fission and fusion neutron exposure of materials has been recognized and addressed for some time now [2]. In response to a desire to reduce the radioactivity of materials exposed to neutrons in fusion, alloy elements were replaced/minimized with much lower activity elements (e.g. Mo by W or V, Nb by Ta), creating the reduced activation ferritic-martinsitic (RAFM) steels, which are now the basis for all worldwide efforts to pursue fusion power plants. In addition, the materials community has identified and verified that precipitates in solids can be used to enhance strength and operating temperatures, and to trap the helium produced by fusion neutrons, thereby mitigating the degradation mechanisms associated with this gas produced in solids. Advanced RAFM steels are being developed at the laboratory level and activities to pursue industrial level production are being explored. Extending the lifetime and reducing the radioactivity of these materials in the harsh fusion nuclear environment is a task that the fusion research community is tackling. The issue is how long can these materials last in a fusion reactor designed for commercial use until they have to be replaced.

2) Radioactive waste

Fusion power plants will generate radioactive waste. However, all of this waste can be classified as low level waste (LLW), allowing its disposal in shallow burial repositories. In contrast, fission power plants generate LLW, intermediate level waste (ILW) and high level waste (HLW). Fission waste as spent fuel assemblies must be disposed of in deep geological repositories to guarantee no contact with the biosphere for many hundreds of thousands of years (e.g. Yucca Mountain). The volume of LLW and ILW generated per year from a PWR is ~ 200-350 m3 [3]. For a 40 year plant life, the HLW volume is ~ 800 m3 and LLW/ILW volume is ~ 8000-14000 m3. Here we are quoting World Nuclear Association data [3] for operating fission power plants.

The estimated fusion waste volumes range from 1500-8000 m3 [4] including the multiple fusion core blankets required during the plant’s lifetime, assumed to be about 50 years. These waste volumes are not significantly different from fission waste volumes, however efforts continue in the fusion community to minimize this waste [5] by 1) choosing/developing low activation materials, 2) controlling impurities in materials, 3) recycling/clearing plant materials with little to no induced radioactivity, 4) controlling the material choices where possible to allow recycling/clearance after short periods of time (1-10 years), and 5) guaranteeing that the highest radioactivity wastes will decay to low levels in a few decades after they are removed from the fusion core.

Nuclear analysis has shown how strongly the radioactivity of materials can be reduced when specific elements are controlled, and this is the reason the fusion program is pursuing improved materials so aggressively. These materials are not phantasm.

Contrary to the Jassby’s claim, there is a private company in West Texas, WCS Corporation, supported by its surrounding community, that already operates two LLW waste facilities, and has applied for NRC licenses to operate a consolidated interim storage facility to prepare used nuclear fuel for long term disposal at a geologic repository.

3) Radiation shielding

Radiation shielding is required in fusion power plants, and remote handling of all operations inside of the bio-shield (the barrier separating where humans can work with no impact on their exposure) in a fusion power plant is mandatory. We have a great deal of experience shielding, monitoring and handling of radiation sources through the use of neutron absorbing materials and remote handling equipment. The experience of remote handling on fission power plants, and at research hot cell facilities (going on for nearly 5 decades) is considered a very strong basis for fusion’s needs. A good example of our existing remote-handling capability is the fact that no human being has ever entered the H-Canyon facility at the Savannah River Site [6] over the 60-year span of its use in the handling, processing and disposal of special nuclear materials. The development of systems relevant to fusion is an important part of the fusion program.

4) Tritium release

Since tritium is not naturally occurring, a fusion power plant must generate its own tritium, by taking advantage of the neutrons produced through their interaction with lithium-based compounds in the blanket. Detailed calculations of the neutron behavior show that breeding enough tritium is achievable, and a recent JASON study [7] independently confirmed this conclusion.

Tritium WILL NOT BE RELEASED to the atmosphere in a fusion power plant from breaches in reactor vacuum ducts, heat exchangers, etc. Tritium permeation is NOT a critical unsolved problem in fact complex situations have been studied including tritium behavior in neutron irradiated samples while exposed to tritium plasma. Predicted total tritium levels in a fusion power plant can range from ~ 1-10 kg, which is much higher than the tritium levels produced in a fission power plant. For comparison, the Savannah River National Laboratory, which is the primary tritium and nuclear material handling laboratory for U.S. defense (and many other functions), has an inventory limit of 7 kg of tritium, and a processing rate of 2-3 kg of tritium per year. For ITER, the on-site inventory limit for tritium is 4 kg, and the targeted maximum loss is ~ 27 Ci/day. The containment and control of tritium is a fundamental design aspect of a fusion power plant, involving identifying all sources/inventories, all migration pathways, all forms (e.g. gas, water, dust), all materials interfaced, all environmental parameters both normal and off-normal (e.g. temperatures, pressures), all interfacing equipment (e.g. pumps, extraction, heat exchanger, purification, storage), and establishing a plant wide series of isolation rooms, regions, and buildings. Multiple barriers are utilized throughout the plant. All appropriate forms of de-tritiation will be present in a fusion power plant from the fusion core to the turbine building.

Tritium releases from fission power plants vary widely. For 2004-2005 [8] gaseous releases range from 1 to 972 Ci (1 Ci = 10-4 grams of tritium), and the liquid effluent releases ranged from 142-2951 Ci. Comparing the fusion targeted limit of 3650 Ci/year, the releases would be similar, albeit the fusion power plant would have an extensive tritium sequestering and control system in place since its plant tritium inventory is much higher than fission. Tritium is one of the most critical quantities in a D-T fusion power plant, and this guides the fusion community’s emphasis on all tritium aspects.

5) Nuclear proliferation

Using a fusion reactor for proliferation is at least as impractical as using a commercial fission reactor to produce weapon grade plutonium. Proliferation cannot be described in any depth in a letter such as this, and so we refer to the several journals, papers and workshops on the topic [9,10]. The need for IAEA standards and safeguards for a fusion power plant does not appear to us to present a barrier to fusion power production, or even a discouragement, particularly since the IAEA has been involved in a wide range of fusion development activities for over 40 years already.

6) Coolant demands

Fusion power plant designs over the last 30 years have generally moved away from water as a coolant due to its limitations in the operating temperature (< 330C), high required pressures to avoid boiling (20 MPa), safety issue of water-lithium interactions, possibility of hydrogen explosion when water is dissociated during accidents (like Fukushima), and limitations in thermal conversion efficiency to make electricity. Helium is most often used as the coolant, and water is even eliminated as the secondary coolant in order to keep thermal conversion efficiency high (~45-60%) including the use of a bottoming cycle to utilize the waste heat to further improve efficiency. A great deal can be done to minimize water usage, these techniques are known, and they will not limit fusion’s potential.

7) Outsized operating expenses

Jassby’s reference to ITER electricity consumption whether during plasma operation or not, is not a relevant benchmark to judge fusion power plants. ITER’s mission is to demonstrate the sustained burning plasma for times long compared to plasma time scales and with sufficient gain (fusion energy produced by the plasma per energy injected into the plasma). It has no mission whatsoever to produce electricity, to minimize recirculating power, or to demonstrate efficient subsystems, all relevant goals of a power plant. The factors mentioned, recirculating power and replacement of fusion core components, have been included in conceptual power plant studies and viable power balance and net electricity production have been found.

Energy Security is a Fundamental Part of National Security

The path we are on in eventually eliminating coal and nuclear fission reactors raises serious national security concerns. The real challenge we face is to create technically and economically feasible options over the next 35 years. This will require strong dynamic leadership with vision, serious efforts in long-term planning and sustained investment in high-risk/high-payoff R&D. The annual expenditure on energy in the US is ~ 1.2 trillion dollars, which comprises about 8.5% of the gross domestic product, and the 5 billion dollars spent on energy research per year appears to be utterly inadequate. Given the shortfall in electricity described above by 2050 and the limited options afforded by the current path we are on, more funding should be devoted to a portfolio of credible options for our long-term energy needs such as advanced fission reactors and fusion. Since we do not know what the future will bring, this would be a sensible hedging strategy to provide us with energy security options to adapt to a highly uncertain future.

Dr. John A. Parmentola, Adjunct Staff, RAND Corp., jparmentola@cox.net

Dr. Charles E. Kessel, Princeton Plasma Physics Laboratory, ckessel@pppl.gov

References

1. http://scitation.aip.org/content/aip/magazine/physicstoday/article/66/2/10.1063/PT.3.1867
2. S. J. Zinkle and J. T. Busby, Materials Today, http://www.sciencedirect.com/science/article/pii/S1369702109702949
3. http://www.world-nuclear.org/information-library/nuclear-fuel-cycle/nuclear-wastes/radioactive-waste-management.aspx
4. L. El-Guebaly, et al, Fusion Science and Technology, vol 67, (2015), 179.
5. N. P. Taylor, et al, http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.135.1187&rep=rep1&type=pdf
6. Savannah River National Laboratory (F-Canyon and H-Canyon) http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.558.7021&rep=rep1&type=pdf
7. JASON report on Tritium, http://fire.pppl.gov/jason_tritium_fusion_2011.pdf
8. http://www.ieer.org/sdafiles/16-1/tritium_releases.html
9. The Nonproliferation Journal, http://www.tandfonline.com/doi/full/10.1080/10736700.2013.852876?src=recsys
10. A. Glaser and R. J. Goldston, Nuclear Fusion, vol 52, (2012), 043004.