Science AMA Series: I am Shannon Bragg-Sitton, I lead a research program at Idaho National Laboratory. We are developing sustainable energy systems that maximize the use of low-carbon energy generators – specifically nuclear and renewables. I’m here with a few members of my team. Ask us anything!

Abstract

Hi Reddit!

My name is Shannon Bragg-Sitton and I’m here today with a few other researchers from Idaho National Laboratory. This is Nuclear Science Week, so we thought it would be great to start a conversation about low-carbon energy systems – specifically nuclear and renewables.

Commercial nuclear power currently provides nearly 75 percent of the U.S. emission-free power, according to the Nuclear Energy Institute. INL is leading the development and understanding of hybrid energy systems that would combine renewable energy, fossil energy and nuclear energy in highly efficient, low carbon dioxide systems that provide electricity, transportation fuels and chemical products all at one plant.

· Shannon Bragg-Sitton, Ph.D., senior nuclear engineer and lead of INL’s Nuclear-Renewable Hybrid Energy Systems program

· Gilles Youinou, Ph.D., Manager of Reactor Physics Design and Analysis

· Richard Boardman, Ph.D., Systems Science and Engineering

· Richard Hess, Ph.D., Energy and Environment Science & Technology Directorate

If you are interested in reading some of our research, please see these OSTI reports:

http://www.osti.gov/scitech/biblio/1177627-rethinking-future-grid-integrated-nuclear-renewable-energy-systems

http://www.osti.gov/scitech/biblio/1170315-integrated-nuclear-renewable-energy-systems-foundational-workshop-report

http://www.osti.gov/scitech/biblio/1236837-nuclear-hybrid-energy-systems-regional-studies-west-texas-northeastern-arizona

http://energy.gov/sites/prod/files/2016/06/f32/QTR2015-4K-Hybrid-Nuclear-Renewable-Energy-Systems.pdf

We’ll be back at 1 p.m. EST (11 a.m. MST, 10 a.m. PST) to answer your questions, ask us anything!

Thank you, Reddit Community, for all of the great questions! We've worked through as many today as possible and will answer more as time permits. We look forward to addressing additional topics in the future!

Do you believe there could be a demand for small modular reactors in the US, and are there any small modular reactors being developed that actually have potential of getting licensed and constructed within the next ten years?

TomVenn

Yes. Small modular reactors (<300 MWe each, per the IAEA definition) could certainly have a place in the US energy markets. As more and more distributed energy systems are built (e.g. variable renewable sources), smaller implementations of nuclear fission reactor technology may also fill a need, particularly in parts of the country that are not densely populated. As mentioned by RedGene, NuScale is working toward a prototype facility in the early 2020s. The NuScale concept is an integral pressurized water reactor (PWR) technology, such that is a relatively small step from our current light water reactor (LWR) fleet versus a dramatic change in reactor design and cooling technology. Use of water-cooled technology will shorten the regulatory timeline for licensing (versus an advanced reactor concept) and is certainly feasible in less than 10 years. See http://www.nuscalepower.com/our-technology/technology-validation/program-win/uamps for information on the NuScale project in association with UAMPS, the Utah Associated Municipal Power Systems. --Shannon Bragg-Sitton


What are you thoughts on the advanced reactor concepts in development both in industry and research? I've heard a lot of good promises about molten salt and thorium reactors lately

newcleardrew

Everyday is like Disneyland for me. There are exciting nuclear and renewable energy rides to get on all around us. We have the opportunity to address deep decarbonization by building an energy infrastructure that utilizes clean/cleaner energy sources. Our work under DOE and with developers of small modular nuclear reactors and the manufacturing sector, in part, is to determine how clean energy can be efficiently and effectively delivered to industry. The cost of heat is key, but our projections indicate that thermal energy from a nuclear reactor may soon be cost competitive with fossil fuel sources. Can you imagine how the cost of producing nuclear heat can be reduced with mass manufacturing of modular reactors, which could be implemented faster as we gain experience with permitting and operations of these units? Our projections indicate around 1000, 150 MW-thermal modules could be used to provide heat to the U.S. industry today. This number could be much higher as we transition to electric vehicles and hydrogen fuel cell vehicles. It could also be increased when we learn how to convert carbon resources like biomass and coal (yes, even coal) to durable products in the plastics, resins, and the surging carbon fiber materials market. We need to continue studies and analyses that help us develop sustainable, most likely integrated, energy systems.

--Richard Boardman


Hello! Thanks for doing this AMA. I've been independently studying nuclear energy and science for awhile and I'd like to ask about your feelings on 2 different reactor types in use today.

First, is there any reason why we, as in the United States, don't use more natural uranium reactors? I read somewhere that enriched uranium reactors make up 80% of US reactors. I think this is odd, considering CANDU reactors burn more uranium, more efficiently, and yet we refuse to use them.

Secondly, how feasible are Integral Fast Reactors, and do you think that if the United States adopted them we could decrease nuclear waste levels? I know that the high energies of the neutrons released in fast reactors have a high cross section for fission with long lasting actinide series waste. If true, why don't we use them?

Thanks again for the AMA!

PenisMcFartPants

Dear PenisMcFart, thank you for those two good questions. First of all, enriched uranium reactors make up 100% of US reactors, not 80%. Economics is the most important part of the equation when it comes to implementing an industrial strategy and the economics of nuclear power is only weakly dependent on the amount of uranium a reactor burns. The reactor technology using enriched uranium was developed in the US in the 50's whereas the CANDUs were developed in Canada. If CANDUs are not used in the US, it must mean that the cost benefit analysis performed by industry is not in favor of it. Integral Fast Reactors would use about 100 times less natural uranium than CANDUs or enriched uranium reactors to produce the same energy. With world natural uranium resource amounting to at least 8 million tonnes and another 1.5–2 million tonnes of depleted uranium accumulated from the operation of uranium enrichment plants throughout the world, Integral Fast Reactors could provide electricity for at least 3000 years even if, alone, it had to produce the total current electrical power coming from coal, gas,oil and nuclear combined. I believe these reactors will eventually become necessary to meet the world growing need for electricity. --GJY--


Hello! Thanks for doing this AMA. I've been independently studying nuclear energy and science for awhile and I'd like to ask about your feelings on 2 different reactor types in use today.

First, is there any reason why we, as in the United States, don't use more natural uranium reactors? I read somewhere that enriched uranium reactors make up 80% of US reactors. I think this is odd, considering CANDU reactors burn more uranium, more efficiently, and yet we refuse to use them.

Secondly, how feasible are Integral Fast Reactors, and do you think that if the United States adopted them we could decrease nuclear waste levels? I know that the high energies of the neutrons released in fast reactors have a high cross section for fission with long lasting actinide series waste. If true, why don't we use them?

Thanks again for the AMA!

PenisMcFartPants

Hello: These are very good questions. I'm going to respond in a slightly different manner. There are several types of reactors, and they each have certain benefits in terms of fuel burnup, waste minimization, and safety considerations. A recent publication on small modular reactors by Dan Ingersoll and his co-authors discusses a new class of reactors that are being developed, and this reference can answer many of your questions. Our interest is in using nuclear energy to provide heat and power to industry and manufacturing processes. Therefore, we are interested in the outlet temperature of the cooling fluid, and how to safely transfer this heat to industry so we can reduce fossil fuels combustion and CO2 emissions. A high temperature gas cooled reactor can provide a thermal source for many chemical manufacturing industries for example. Molten salt reactors may also provide a heat source for processes that require superheated steam. But even a water-cooled reactor - including the variety you bring up -can provide the vast majority of process steam that is used by industry. Today's SMR designs include many reactor technologies - water cooled, salt cooled, metal cooled, and gas cooled - and incorporate various passive safety approaches. We are working to match these technologies to industrial heat profiles to fully maximize the utilization of clean energy technologies.


It seems like one of the worst problems surrounding nuclear energy today is reactors cost that has gone through the roof. What's your opinion on this? Indeed incredibly few reactors have been proposed, let alone finished, in the west in the last decades. Can we fix this?

lucaxx85

This is the key question and concern. Kradist is right- waste is part of the consideration and cost. All energy forms have their pluses and minuses. We do need to be aware of the size of the problem we are working on, and the consequences of not making any substantial change on an international level.

But to your question, the hope is that the cost of nuclear energy, the same as anything, can be reduced by creating a system of supply and mass manufacturing, and permitting experience, that can reduce these costs significantly- maybe 30-50% is possible. Experience and a well developed supply chain would reduce the time frame to get projects approved and built.

My opinion is yes, the costs can be reduced and likely will be reduced, before we mention the jobs this could create in the metals and fuels industry.


With the West and Southwest having access to good solar and being water stressed, can integrating nuclear reduce the overall water usage for the benefit provided? How would integrating processes that could utilize the the high quality heat be approached from a regulatory standpoint? (Conventional chemical plant sited with a nuclear plant)

PowerfromBeards

Very good questions- actually several questions.

The good news is that advanced high temperature nuclear reactors can be coupled to Brayton power cycles that do not use water in the steam loop and cooling towers. Supercritical CO2, He, and Air can be heated and used to drive gas turbines.

Further, industrial heating can be done with heat transfer media other than steam. Dowtherm (trademark name) is an organic fluid that could be used for heat transfer from nuclear reactors to industry heat users.

On nuclear plant sizing, the hope is that the reactor exclusion zone can be reduced with small modular reactors that incorporate passive safety and have a reduced source term relative to large scale power reactors. Risk assessment and safety considerations will need to be considered at several levels.


Do you find yourself completely exasperated with the politics surrounding nuclear power, like Yucca Mtn for instance?

knotwheely

Stepping back and re-thinking something is an important aspect of getting things right the first time. We need to be responsible for making informed, science-based decisions with relevant and relative perspective on the "take no action" option. DOE leadership, academic institutions, and other voices in the energy community and marketplace are understanding nuclear energy is a reliable, resilient, non-volatile, clean energy source. Therefore, it's worth our efforts to determine out how to best mange used nuclear fuel in the near and long term. Similar discussions come up around the materials used for renewable energy devices. In all cases, development and deployment of future energy systems should include full life cycle assessments.


What is the status of thorium reactors? Is this a viable form of energy generation?

lf11

The Chinese Academy of Sciences - Shanghai Institute for Nuclear and Applied Physics- is developing a thorium molten salt reactor (TMSR). While there is no current shortage of uranium in the world, the relative abundance of thorium is a driver for China's interest in this class of reactors. INL is working with SINAP to consider how this reactor, and also U.S. small modular reactors (SMRs) can be used in hybrid energy systems that go beyond electrical markets.


What is the status of thorium reactors? Is this a viable form of energy generation?

lf11

The Chinese Academy of Sciences - Shanghai Institute for Nuclear and Applied Physics- is developing a thorium molten salt reactor (TMSR). While there is no current shortage of uranium in the world, the relative abundance of thorium is a driver for China's interest in this class of reactors. INL is working with SINAP to consider how this reactor, and also U.S. small modular reactors (SMRs) can be used in hybrid energy systems that go beyond electrical markets.


What can the average person do to transition his/her community to clean renewable energy?

starlord6430

An excellent question, but one, I fear, that would be answered in a way possibly leaving you unsatisfied... I will attempt an answer nonetheless :) An important step that can be taken in any community is to engage in and sustain conversations on energy sources, the local or regional balance of energy production versus demand, and consideration of energy efficiency improvements. Such conversations could help the community define and understand what are their common energy ideals. From this, actions at the local level may be defined, ranked, and considered, such as changes to building codes for energy efficiency, or applying property tax incentives to help bring in clean energy generators. Finding consensus may be difficult in a community with varied interests, but the respect and understanding coming from the conversation alone is often empowering. Good luck! ~Phil Sharpe, Director of Nuclear Systems Design and Analysis, Idaho National Laboratory


Does nuclear mesh well in a grid alongside renewable sources?

I've always got the impression that nuclear is fairly limited for this purpose, compared to gas, because traditionally it's been difficult to switch nuclear on and off in response to demand, and because the capital cost dominates the fuel cost, which means you don't save any money by leaving the plant offline (unlike with gas, where fuel costs might be 50% of the cost of generating power, which you can save if the plant is switched off).

Are those serious problems in your opinion, and if so are they being tackled?

What role do you see nuclear playing in a future grid, should it be a relatively small percentage, say 5-15%, to try to meet the baseline of 24h demand, or should it be a lot more than that? Perhaps a really large percentage like we see in France?

Thanks!

JB_UK

Nuclear generation is ideally suited for baseload operation. However, nuclear power plants can be operated flexibly and have been operated in this manner for quite some time in France. Hence, operation in this manner is technically feasible, but, as you point out, is not an economically preferred option for the plant owners because dialing back on the power output does not change the capital and operating cost for the plant. We are tackling that issue by looking at use of nuclear energy beyond the electricity sector alone. In the "hybrid" energy systems (HES) research that we conducting, we consider "load dynamic" versus "load following" operation of nuclear plants. In this manner the output of the nuclear reactor remains at its normal operating level, but the thermal energy is either directed toward electricity generation OR other applications based on the net load on the grid. That "other" energy user could be a number of industrial applications that use either electrical or thermal energy, such as water desalination, hydrogen generation, synfuel production, etc. In order to meet the carbon reduction goals that have been established by the US and other developed countries (see the COP-21 meeting agreements), nuclear must be a major contributor to future energy systems - including the grid and industrial energy users.

See http://energy.gov/sites/prod/files/2016/06/f32/QTR2015-4K-Hybrid-Nuclear-Renewable-Energy-Systems.pdf for more information on the HES research.

--Shannon Bragg-Sitton


Does nuclear mesh well in a grid alongside renewable sources?

I've always got the impression that nuclear is fairly limited for this purpose, compared to gas, because traditionally it's been difficult to switch nuclear on and off in response to demand, and because the capital cost dominates the fuel cost, which means you don't save any money by leaving the plant offline (unlike with gas, where fuel costs might be 50% of the cost of generating power, which you can save if the plant is switched off).

Are those serious problems in your opinion, and if so are they being tackled?

What role do you see nuclear playing in a future grid, should it be a relatively small percentage, say 5-15%, to try to meet the baseline of 24h demand, or should it be a lot more than that? Perhaps a really large percentage like we see in France?

Thanks!

JB_UK

This is indeed the proposition of hybrid energy systems and is the subject of studies DOE is funding under Shannon Bragg-Sitton (INL) and Mark Ruth (NREL). Also refer to studies by Charles Forsberg at MIT for some examples. Europe, China, and India are also each working out hybrid energy schemes. Some of these are looking to make hydrogen when there is excess generation capacity on the grid.


You guys are one of the few places that has experimented with the Sulfur-Iodine cycle. What do you think of it? What needs to be done in the future?

Gforce7543

There are several thermal-chemical cycles that can produce hydrogen, and sulfur-iodine is one that received DOE funding to develop. Japan has continued R&D for this cycle. Materials and catalysts for harsh environments are research opportunities for this process.

I am personally impressed with the hybrid sulfur process which does not use HI; but does use one step that is similar to sulfur-iodine. This is the sulfuric acid decomposition reactor.

High temperature steam electrolysis is, however, the most advanced at this time, but I believe there are future opportunities for thermal chemical cycles as well. These may include solar thermal-chemical hydrogen or very large industrial hydrogen plants. Systems engineering and plant design analysis are needed and are foundational to higher systems analysis. Hybrid systems require analysis at multiple levels.

On this note, search the internet on H2@Scale to learn more about the connection of nuclear energy to hydrogen production, and where hydrogen could be an important key to transferring nuclear and renewable energy into the transportation and industrial manufacturing sectors.


Is there any research ongoing into making next generation nuclear reactors more flexible with regards to their output? Nuclear is excellent for baseload but with more and more solar and wind power coming online the grid requires more flexibility than ever. Can nuclear ever be part of a peaking system or would we have to rely on grid level storage or gas turbines to meet variable demand in a nuclear based energy grid?

epicluke

Nuclear generation is ideally suited for baseload operation. However, nuclear power plants can be operated flexibly and have been operated in this manner for quite some time in France. Hence, operation in this manner is technically feasible, but, as you point out, is not an economically preferred option for the plant owners because dialing back on the power output does not change the capital and operating cost for the plant. New plant designs are considering the potential need for flexible generation and are expected to be able to operate flexibly within established constraints regarding ramp rates, minimum turndown, etc., but this does not solve the fact that when an asset is operated at a reduced level plant income is reduced while operating costs are essentially the same.

We are tackling that issue by looking at use of nuclear energy beyond the electricity sector alone. In the "hybrid" energy systems (HES) research that we conducting, we consider "load dynamic" versus "load following" operation of nuclear plants. In this manner the output of the nuclear reactor remains at its normal operating level, but the thermal energy is either directed toward electricity generation OR other applications based on the net load on the grid. "Net load" is the remaining demand that must be met by conventional generation sources after variable generation is subtracted from the total load (demand). The "other" energy user in an integrated, hybrid energy system could be a number of industrial applications that use either electrical or thermal energy, such as water desalination, hydrogen generation, synfuel production, etc. In order to meet the carbon reduction goals that have been established by the US and other developed countries (see the COP-21 meeting agreements), nuclear must be a major contributor to future energy systems - including the grid and industrial energy users.

See http://energy.gov/sites/prod/files/2016/06/f32/QTR2015-4K-Hybrid-Nuclear-Renewable-Energy-Systems.pdf for more information on the HES research.

--Shannon Bragg-Sitton


Electric cars are becoming real. How will existing or near-future infrastructure cope with this new demand ?

Neker

This is a good point. But also hydrogen fuel cell car and trucks will likely be a part of our future transportation system. They may all be self-driven and coordinated. DOE is helping the auto industry with SMART Mobility as well. But back to energy... Replacing the internal combustion engine (ICE) with electric vehicles (EV) and fuel cell vehicles (FCV) will require double or triple the amount of electricity that is currently generated. So, if we want to have a clean transportation sector, we need to build out clean electrical power and clean heat sources. Renewables and nuclear offer this clean energy resource. Clean coal may also be part of the mix. We need to work together with systems analysis to create the right energy infrastructure that allows us to get the right form of energy to the right location at the right time. I like to think about this as the delivery of electrons (electricity), protons (hydrogen) and heat (photons).

And, by the way, we'll probably see ICE stay around for some time, so we should think about making it cleaner with clean energy. That could start with steam and hydrogen that is produced without CO2 emissions.


What books would you recommend that a high school library offer students, parents, and teachers who'd like to educate themselves about your field, from an environmental and/or scientific perspective?

JediLibrarian

From Gilles Youinou. "Sustainable energy without the hot air" is a great book and can be downloaded for free. The International Atomic Energy Agency is also a great resource. For example their 2013 report "Climate Change and Nuclear Power" or their 2012 report "Nuclear Technology for a Sustainable Future" provide useful information (and can be downloaded for free)


What is the best tactic to use when discussing nuclear power with someone who is emotionally invested in their anti-nuclear stance, or is it worth the effort?

CriticalDog

It is definitely worth the effort. My suggestion is to come with facts and data. Don't get worked up in these discussions - it shouldn't be a debate - but instead provide information using laymen's terms that supports the safety of nuclear power. Nuclear power provides clean energy and has done so reliably for decades, with fewer accidents and fatalities than other energy generation systems. Point to some of the former anti-nuclear environmentalists who, when faced with facts and data, changed their positions. Pandora's Promise is a great documentary film that highlights some of the misinformation that drives these emotional responses.

--Shannon Bragg-Sitton


What is the best tactic to use when discussing nuclear power with someone who is emotionally invested in their anti-nuclear stance, or is it worth the effort?

CriticalDog

From Gilles Youinou. In order to mitigate the impact on the climate, the latest report of the Intergovernmental Panel on Climate Change says that CO2 emissions from the power sector should be reduced by 90 percent or more below 2010 levels between 2040 and 2070. Currently, about 22 trillion kilowatt-hour (kWh) of electricity are necessary to power the world economy; about one third, 7 trillion kWh, come from low-carbon sources (hydropower and nuclear and also, to a lesser extent, wind, solar and geothermal) and two thirds, 15 trillion kWh, come from fossil fuel (coal, gas and oil). By mid-century, the International Energy Agency predicts that the demand will rise to about 40 trillion kWh and, if the CO2 emissions are to be cut by 90 percent, no more than 1.5 trillion kWh should come from fossil fuel (10 percent of the current production). Consequently, between now and 2050, the generation of electricity coming from low-carbon energy sources should increase from 7 trillion kWh to about 38.5 trillion kWh. This is a challenge that wind and solar can probably not address alone; Nuclear should be part of a balanced solution.


How is nuclear sustainable when we don't have a good solution for the waste? I live in WA state and we have had 60 years of problems with the Hanford site leaking nuclear waste. If we create a ton more won't it just ruin the environment around every site, get into the water, exc...?

PuckTheFairyKing

From Gilles Youinou. Technical solutions exist and the management of the used nuclear fuel assemblies is at least as much a political and societal problem as an actual technical problem. A typical 1 gigawatt nuclear reactor of current pressurized water technology generates about 7 billion kWh per year, enough to power the city of San Francisco. Every year this nuclear reactor generates 35 used fuel assemblies containing about 1.1 tonne of highly radioactive, elements—out of which 200 kg is plutonium—together with about 17 tonnes of unused uranium. The volume occupied by these 35 fuel assemblies is about 6.2 cubic meters. Assuming a typical consumption of 7,000 kWh per year, a person living in San Francisco would be responsible for the production of about 6.3 cubic centimeters of used nuclear fuel per year weighing 18 grams if the electricity came only from a nuclear power plant. It would take about 55 years for this person to fill the equivalent of a can of soda with used nuclear fuel. Fifty-five years! So, yes, these used fuel assemblies contain very dangerous materials—standing next to one, unprotected, would kill you in a few minutes—but there is very little of it. If the same electricity had come only from a gas—natural or bio—power plant during the same 55 years, that person would have been responsible for the emission of about 190 tonnes of CO2—900,000 cans of soda or one every half-hour—and twice that amount if it had come from a coal power plant.


Since the need for renewable energy has somehow become a political issue, do you find it hard to find community support for renewables when you live in such a Red state? (I also live in Idaho)

jabroniusmonk

That's a hot potato question (pun intended for Idahoans).

Renewable energy costs are coming down, but intermittency will always be a challenge. Nuclear energy costs can also be reduced as more plants are built- but the first few may need some financial assistance to overcome initial investment challenges.

Hybrid systems are an approach to optimize the technical and economical value of the energy system. Red or Blue, we will all make the right decision based on good science, good engineering, and good economics.

Policy and regulations are sometimes used to achieve social values, or to help markets to adjust to a position that is good for everyone. I like to bring up the example of the aluminum industry- which was orchestrated under the Defense Production Act to provide aluminum for aircrafts as quickly as possible. Now, each life is touched by low-cost aluminum everywhere.

Affordable, clean, reliable energy is where I think we need to be headed. This requires systems analysis and is region dependent. In summary, whether its renewable, nuclear, and clean fossil energy, we need to decide the best future energy system and collectively decide how to get to that state in a free economy.


Thanks for doing this AMA! Question: with the recent news that global CO2 levels have crossed the 400ppm threshold, has the work your team is doing been impacted in any way and how? Do you anticipate any changes going forward?

stbillings

There are many agreements, statements of goals, etc. that are coming out from the COP-21 meeting that was held in Paris in December 2016. There are various resources online that clarify these agreements. In short, the rising CO2 level is recognized as a growing concern at a global level. The US is taking emission reduction goals seriously, and I anticipate that this will result in continued investment in future energy system technologies that will allow us to reduce emissions across all energy sectors - electricity, industry, and transportation. Decisions regarding future energy systems, and associated policies, must take into account potential impact on energy reliability, grid resilience, energy security, etc.

-Shannon Bragg-Sitton


Given the nation's diminishing reserves of certain radioactive isotopes, do you have any plans to turn your breeder reactor(s) back on? Or are they completely dismantled now?

krillr

The US has no breeder reactor currently operating. The last test reactor using this technology was shut down in the 90s. However radioactive isotopes used for medical or industrial applications are still produced in other reactors in the US (ATR and HFIR) --GJY--


Hey guys, thanks for doing this awesome AMA! I work for a renewable energy contractor and we specialize in utility scale development. I wanted to know about the scalability of the projects you're working on? Could we be seeing nuclear hybrid systems sized to service Energy Coop demands in the 20-50 megawatt range? Or possibly smaller systems sized to service islanded communities or industries? If so, what does the timeline look like? Thank you!

Tamany_AlThor

The concepts we are looking at are certainly scalable. A single NuScale reactor module would provide approximately 50 MWe - a good match to the size of typical wind farms. We could also consider even smaller systems if they meet the energy needs of a specific location, community, remote facility, etc. I have previously conducted research on very small space nuclear power and propulsion systems -- a remote installation on the moon or Mars must, by design, be a "hybrid" system (or a cogeneration system) capable of reliably providing the necessary thermal and electrical generation to support the facility/base. --Shannon Bragg-Sitton


As an average citizen, I worry not only about nuclear accidents, but the storage of waste materials. I understand the excitement about nuclear energy, but shouldn't a solution also be developed to make the waste product safe or recyclable? To me, that is just common sense.

rosygoat

Technical solutions exist and the management of the used nuclear fuel assemblies is at least as much a political and societal problem as an actual technical problem. A typical 1 gigawatt nuclear reactor of current pressurized water technology generates about 7 billion kWh per year, enough to power the city of San Francisco. Every year this nuclear reactor generates 35 used fuel assemblies containing about 1.1 tonne of highly radioactive, elements—out of which 200 kg is plutonium—together with about 17 tonnes of unused uranium. The volume occupied by these 35 fuel assemblies is about 6.2 cubic meters. Assuming a typical consumption of 7,000 kWh per year, a person living in San Francisco would be responsible for the production of about 6.3 cubic centimeters of used nuclear fuel per year weighing 18 grams if the electricity came only from a nuclear power plant. It would take about 55 years for this person to fill the equivalent of a can of soda with used nuclear fuel. Fifty-five years! So, yes, these used fuel assemblies contain very dangerous materials—standing next to one, unprotected, would kill you in a few minutes—but there is very little of it. --GJY--


INL is currently working on licensing a site for the construction of an SMR designed by Nuscale. From what I remember, these reactors, once constructed, will power Salt Lake City. Since this is a commercial power reactor, why was it chosen to be located at INL over a private site owned by the utility?

Triggerhappyspartan


Can spent fuel rods be repurposed? Do they have any lingering qualities that could be used for power or is it possible to refine them in some way?

misterhamtastic

From Gilles Youinou. If spent fuel rods are reprocessed, like in France for example, the plutonium can be extracted and reused in a reactor to produce electricity.


Are there any other promising nuclear technologies out there that we haven't heard much about yet?

Reddit_Account_2

Well, that depends on what you've heard about! There are a variety approaches to reactor design that have been researched in the past and that are currently being researched (liquid metals, gas, and molten salt cooled reactors are just a few of the options out there). The DOE advanced reactor technology program considers development of several of these technologies, and a variety of research is being conducted around the world as well that go beyond the most prevalent water-cooled reactor designs. The Gen IV International Form (GIF) is a good resource for advanced reactor concepts.

--Shannon Bragg-Sitton


It seems the work you all are doing involves the optimization of existing technology rather than new technology (though I understand it is the integration of these technologies that is new).

What new/emerging technologies do you think will be utilized by your work? Which of the existing technologies are least developed? Which technologies don't exist but would be immensely helpful?

maelstrom3

Part of our research here at INL and at other national laboratories is certainly considering optimization of existing technologies to maximize utilization of clean energy generation sources. This is certainly a necessary step for future energy systems.

Integration of diverse energy technologies requires additional instrumentation and smart control systems, introducing the need for new and diverse cyber security approaches relative to independent energy systems.

--Shannon Bragg-Sitton


It seems the work you all are doing involves the optimization of existing technology rather than new technology (though I understand it is the integration of these technologies that is new).

What new/emerging technologies do you think will be utilized by your work? Which of the existing technologies are least developed? Which technologies don't exist but would be immensely helpful?

maelstrom3

Electrochemical processes that use some portion of electricity and heat is wide open for R&D and could help transform the chemical industry to one that relies less on combustion.

Development of process that could use hydrogen as a reductant, such as the steel industry would be another place to start. Check out the research of Dr. H.Y. Sohn at the university of Utah.

Thermal energy storage and heat delivery at uniform conditions needed by many industries is an area where process invention is possible. Check out ideas by Charles Forsberg.

--Richard Boardman


What branch of engineering do you find most abundant in your field? Also, I've heard from some people within the nuclear industry that "nuclear power is the energy of the future, and it always will be." How do you feel about that? What do you think is the most likely renewable to be the overwhelming source of energy in the future?

L21M

Energy systems design and development involves a number of engineering disciplines. Our team here at INL includes nuclear, mechanical, chemical, electrical, and systems engineers just to name a few.

Nuclear power currently provides just under 20% of the electricity in the US and is the largest provider of clean, non-carbon-emitting electricity. The Nuclear Energy Institute has some great information pulled together on the nuclear energy impact around the world -- see http://www.nei.org/Knowledge-Center/Nuclear-Statistics/World-Statistics for starters. Nuclear is already a major provider of electricity, and will be a significant contributor to global electricity and energy needs in the future as well. If we, as a global community, are serious about reducing carbon and other greenhouse gas emissions then nuclear must be a part of the energy mix.

As for renewable, clean energy sources aside from nuclear, which will be the biggest player in the future is highly dependent on location. Wind and solar photovoltaic costs are decreasing and penetration increasing, but they are only a part of the mix and are not reasonable solutions in all areas. Variable renewables cannot they provide reliable, dispatchable energy on their own. They must be coupled with other resources, such as grid-scale energy storage, increased transmission across grid balancing areas, dispatchable baseload generation, etc. Our future energy demands will be met by a mix of generation sources. The hybrid energy systems research here at INL begins to tackle not only future electricity demands, but also begins to bring clean energy into the industrial and transportation sectors.

--Shannon Bragg-Sitton


I assume your aware of the Untied States NB-36H (aircraft) which was an experiment platform for a nuclear powered aircraft. My question is if a nuclear powered aircraft or space craft is fesable in our life time? Or is nuclear power not the right path to go down for aircraft?

One-2-many

Fortunately the rationale in developing nuclear powered aircraft has subsided, ending with the Cold War the perceived need to maintain a continuously deployed airborne platform for potentially launching nuclear weapons. As one commenter noted, consequences of a crash and shielding for the crew were among the major drawbacks. In my opinion, aircraft powered with nuclear engines have rightly been explored and set aside as not needed.

I will offer an extension of the thought, though, in how nuclear power may enable sustainable aviation. Currently avgas and Jet-A is derived from fossil fuel much as gasoline is for automobiles. The current aviation infrastructure is reasonably efficient, but very carbon-intense. There are available carbon-neutral technologies, however, that use nuclear energy to refine and sweeten biofuel derived from non-food crops or food crop by-products. Arguably one could refer to an aircraft running on this biofuel as being nuclear-powered :) [yes, a bad joke, I acknowledge]. Of course such fuel could be used in ground and air transport, but the technology is not cost-competitive with the current cost of oil (~$50/barrel today) and substantial recoverable oil reserves. If and when we decide to place a value on the social cost of carbon, these technologies will remain in the planning stages only.

Application of nuclear-powered spacecraft may have a future still. Though challenges remain in getting space reactor components into orbit (consequence of launch accidents, payload size limitations, etc.), there remains needs for concentrated energy sources for futuristic space applications. For example, some innovative folks are evaluating the concept of a nuclear power system to energize mining stations on asteroids or moons.
~Phil Sharpe, Director of Nuclear Systems Design and Analysis, Idaho National Laboratory


I'm a 3rd year materials science student and I really want to get into research and development focusing on energy. How many MSEs do you work with? What would be the best skills to have to order to work in your area? Side question: would you take a summer intern?

theideanator

Quite a few of our researchers here at INL (and at other laboratories) have a materials science or materials engineering background. Key issues for advanced energy systems often relate to materials. How will they perform under high temperature environments? How will radiation impact the performance? What corrosion issues need to be considered when exposed to the coolant (water, liquid metal, high temperature gas, molten salt)? How do these material impact coolant chemistry?

Yes, INL has many internship opportunities. Check out INL.gov for postings. You can also send an inquiry to "contact INL" via this site and they can get you in touch with the right researchers for your interest area.

--Shannon Bragg-Sitton


Why is a creating a viable molten salt reactor difficult when Alvin Weinberg already had a working prototype at Oak Ridge in the 1960s? I've heard rumors of lots of groups in many countries working on this and that they have access to Weinberg's notes, but still no MSR.

jwepurchase

Molten Salt Reactors (MSR) and Liquid Metal Fast Reactors (LMFBR) were both under development in the 60s. Their objective was essentially the same: make better use of uranium or thorium natural resource. By the early 70s LMFBRs had won the race and MSRs were put aside. Several companies in the US are now attempting to revive it. --GJY--


How possible is it to reprocess nuclear waste to reduce the amount of what has to be stored? Would reactors be able to reuse any of the reprocessed materials to produce more power? Also, how many more years of nuclear fuel do we have?

Abbo60

Only about 5% of the mass contained in spent nuclear fuel cannot be recycled. The other 95% (mostly uranium but also plutonium) could be reused in breeder reactors. With world natural uranium resource amounting to at least 8 million tonnes and another 1.5–2 million tonnes of depleted uranium accumulated from the operation of uranium enrichment plants throughout the world, breeder reactors could provide electricity for at least 3000 years even if, alone, it had to produce the total current electrical power coming from coal, gas, oil and nuclear combined. --GJY--


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