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#551 2023-04-25 00:35:12

Calliban
Member
From: Northern England, UK
Registered: 2019-08-18
Posts: 3,413

Re: Nuclear power is safe

The GE BWR-X300 is likely to be the first SMR to reach commercial operation.
https://m.youtube.com/watch?v=_yiC_QsYI9o&t=194s

This design is simple and highly compact.  If a Martian colony is able to import enriched uranium, then a modified version of this reactor would be quite suitable for the needs of a Martian colony.  We coukd dump waste heat into ponds within ag domes.
******************************************************

Additional: One thing that we could do on Mars is build BWRs that operate at lower output temperature and pressure.  At 450K, the saturation pressure of water is about 10 bar.
https://en.m.wikipedia.org/wiki/Vapour_ … e_of_water

On Earth, this may not be desirable, because output heat has very little value to us, whereas electricity is very valuable.  Operating at lower pressure means accepting lower efficiency.  At 450K, thermal efficiency would be 20-25%, versus 33% for a BWR operating at 100 bar.  But on Mars, we need heat in abundance to support agriculture.  And ease of construction is a more important attribute on a planet with very little industrial infrastructure.

A reactor producing steam at 450K (180°C) could be built as a pressure tube reactor.  The fuel would be loaded into aluminium-magnesium alloy pressure tubes, which would pass through a moderator tank, which would be maintained at a lower temperature.  Aluminium alloys are far more abundant and easier to produce than zircalloy, but are too limiting in temperature for most reactor designs.  Using pressure tubes avoids the need for a pressure vessel.  The output flow from the pressure tubes would enter a steam seperator tank, with steam dryers on the top of the tank.  This arrangement also allows a top down control rod arrangement.

Such reactors could be built at any size neccesary, because reactor size is not impeded by RPV wall thickness.  Very large reactors driving CFC factories supporting terraforming projects, could be constructed at Korelov crater, with waste heat used to melt a subsurface lake.

The safety strategy for pressure tube BWRs would be relatively simple.  The reactors couod be built underground, using soil pressure to provide the modest back pressure needed by the moderator tank.  In the event of loss of heat sink, decay heat would be removed by boiling water in the moderator tank and bleeding off steam.  A surface radiator would recondense the steam back into water, allowing it to reenter the tank by gravity.  This would provide a very long gracetime for additional water supplies to be established in event of loss of heatsink.  The steam bleed DHR system would operate automatically as temperature rises within the tank.  No operator action or electric power wouod be needed.  Reserve water could be kept in a pond, which would also drain into the tank by gravity following valve actuation.  This could be carried out manually by opening the required valves.

Last edited by Calliban (2023-04-25 04:49:26)


"Plan and prepare for every possibility, and you will never act. It is nobler to have courage as we stumble into half the things we fear than to analyse every possible obstacle and begin nothing. Great things are achieved by embracing great dangers."

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#552 2023-04-25 06:16:00

tahanson43206
Moderator
Registered: 2018-04-27
Posts: 17,104

Re: Nuclear power is safe

For Calliban re #551

SearchTerm:Reactor design for Mars using pressure tubes instead of a pressure vessel

Also note prediction of GE SMR design to be first to market.

Google came up with this set of snippets about the proposal to build SMR's in Poland to help them move away from coal...

Polish small reactors project may get up to $4 bln in U.S. financing
www.reuters.com › business › sustainable-business › polish-small-reactors-...

Apr 17, 2023 · ... Finance Corporation may lend up to $4 billion to Orlen Synthos Green Energy's project to deploy small modular reactors (SMR) in Poland.

US ready to lend Poland $4 billion for nuclear energy plan | AP News
apnews.com › article › nuclear-energy-us-poland-221e7fcbe13bba60bd87...

Apr 17, 2023 · A project to develop about 20 small nuclear power reactors in Poland is moving forward as Polish energy company Orlen and two U.S. ...
America wants to lend Poland $4 billion to move away from coal and ...
fortune.com › 2023/04/17 › us-poland-nuclear-power-lending-4-billion

Apr 17, 2023 · A project to develop small nuclear power reactors in Poland is moving forward, with a cooperation agreement between the Polish energy giant ...

Polish plans for large and small reactors progress : New Nuclear
www.world-nuclear-news.org › Articles › Polish-plans-for-large-and-small-...

Apr 17, 2023 · According to the adopted schedule, the construction of the first nuclear power plant will start in 2026, with the first reactor - with a ...

United States Takes Next Step in Supporting Innovative Clean ...
www.state.gov › united-states-takes-next-step-in-supporting-innovative-cle...

Jun 26, 2022 · The United States is committing $14 million toward a Front-End Engineering and Design (FEED) study to provide the basis for the deployment of a ...
US ready to lend Poland $4 billion for nuclear energy plan
www.seattletimes.com › business › us-ready-to-lend-poland-4-billion-for-n...

Apr 17, 2023 · A project to develop about 20 small nuclear power reactors in Poland is moving forward as Polish energy company Orlen and two U.S. ...

If a forum member has time to investigate further, it would potentially be interesting to see what kinds of SMR's may be under consideration.

(th)

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#553 2023-04-26 15:11:31

tahanson43206
Moderator
Registered: 2018-04-27
Posts: 17,104

Re: Nuclear power is safe

https://www.yahoo.com/news/sedan-sized- … 00859.html

The article at the link above is about a micro-reactor.

I ** think ** this design is a spinoff of one already developed for NASA.

The artidle reports that documentation prepared for regularitory review totalled 20,000 pages.

Deseret News
A sedan-sized microreactor could change billions of lives on Earth

Amy Joi O'Donoghue
Tue, April 25, 2023 at 11:00 PM EDT

Yasir Arafat, MARVEL chief designer and project lead, talks about MARVEL, the Microreactor Application Research Validation and Evaluation Project, at the Idaho National Laboratory in Atomic City, Idaho, on Wednesday, April 5, 2023. | Kristin Murphy, Deseret News

Tucked away in a corner of a nondescript building on the sprawling Idaho National Laboratory’s complex in southeastern Idaho, next generation microreactor technology is unfolding and happening at breakneck speed.

Microreactor is a mysterious, uncommon term for the lay person. Most people have heard of a nuclear reactor, but what exactly will a microreactor do and why would Idaho National Laboratory be so intent on making this work and in doing so, bring its first reactor online in five decades?

Think of this:

2.5 billion of the seven billion people on this planet do not have access to electricity.

208 billion people do not have access to clean water.

To achieve a net zero scenario, nuclear investment needs to scale up to well over $100 billion per year in the late 2020s, more than triple of recent investments, according to the International Energy Agency.

Space.com reports the United Kingdom Space Agency recently received funding for a Rolls-Royce project to deploy a small nuclear microreactor for delivery to the moon by 2029. That’s six years from now.

The Microreactor Applications Research Validation and Evaluation project, or MARVEL at INL, is designed to help industry bring the sedan-sized microreactor to commercial deployment.


Earth’s only natural satellite, the moon, is 4.5 billion years old and roughly 240,000 miles away. The practical application for a microreactor on the moon may seem distant and the need hard to grasp, but Alaska presents an easier vision of pragmatic deployment of this technology.

“When we turn on the light switch in our homes, it turns on right away, right? So it is not the same for the remainder of the world,” said Yasir Arafat, a nuclear scientist who is project lead over MARVEL. “The demand for electricity and water is growing and it is very large compared to what we see in the United States. So how do we solve this? And everybody has different answers, but the answer I would like to provide is that it can be 24/7 reliable carbon-free electricity on demand, regardless of geographic location.”

That includes the United States’ own Alaska, where tiny hamlets have their own challenges.

In Alaska, the strength of solar energy generation is easily questionable, as is wind power with the state’s freezing temperatures that lock up necessary components to deliver renewable energy. The go-to energy source? Diesel generators, which are an anathema in this new quest for a carbon-free society.

MARVEL, weighing just over 7 tons, will rope in that technology where feasible, fit in an underground nonvisible containment structure, and with its passive attributes that don’t require hundreds of humans at the switch, deliver the necessary carbon-free energy to electrify and heat the town. This is by no means a megawatt- or gigawatt-sized microreactor, but a Ford-sized component that will easily be manufactured and shipped much like a vehicle where it is needed based on industry demand and community needs.

It’s a marvel, if you will, with its passive design using a Stirling engine patented in 1817 by Robert Stirling, who came up with the concept of mechanically manipulating the ideal gas laws to convert heat into motion or vice-versa via a piston design.


Retiring coal-fired power plants need a replacement. These Western states may have the answer

“I want to tell you my vision of the future. I am kind of an optimist,” Arafat said. “The way I see the future, we are going to be making these microreactors so safe, so benign but also economically feasible.”

Arafat, as detailed by INL in a profile, scratched out his concept for MARVEL with a piece of paper and a box of crayons two days before Christmas one year, envisioning a goal to demonstrate the workability of a novel, state-of-the-art design in a very, very short time frame.

“We have not had a reactor like this before. We entirely designed the system from scratch and the thing that makes this unique is that it does not have any pumps to drive the coolant around the reactor. It is driven naturally.”

Arafat grew up in Bangladesh as a refugee under dire circumstances and found his way to Pennsylvania, where his past living in financial straits helped ignite his future of not just being a dreamer, but a doer who wants to make transformative change.

“The way I think about the globe is that 50% of the world’s population lives on 1% of the footprint on this earth. With microreactors, you can make uninhabitable places livable and again, you can refine water, you get energy. ... It can make opportunities for people to live. We are looking at Mars and other planets for colonization, but on Earth we have a lot of uninhabitable places we can open up.”

So just as the lab’s EBR-I used nuclear energy to turn on four light bulbs in 1951 — a first in the world — along comes MARVEL and the somewhat audacious, ambitious plans for its future.

“So when we started this project, we’d say ‘Hey, we have this opportunity.’ We have not built a new nuclear reactor in a half a century in this country. Let’s try to get the most out of it,” Arafat said. “Let’s not try to do this in 10 to 20 years, let’s try to do this in a shorter time frame, say two to three years. Right? Let’s try to show the world we can be innovative, we can be fast enough that we start something from scratch and be able to completely finish the design.”

It’s been a challenge, but the goal is to get it ready for demonstration just a year from now.

“Building a nuclear reactor is not easy and I can attest to you first hand,” Arafat said. “It is very, very hard.”


The regulatory agency probing the efficacy of MARVEL is asking the right kind of questions but also the tough kind of questions, Arafat said. After a necessary environmental assessment, Arafat and his staff are readying upwards of 20,000 pages of engineering documentation to make sure MARVEL succeeds.

Arafat, demonstrating MARVEL through a series of slide and computer animations, has light in his eyes, a bright smile and passion that is clearly evident as he talks media through the intricacy of this fast-developing project.

“You have to have all the stars aligned, but we can get there,” he said. “That is my hope.”

(th)

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#554 2023-04-28 08:22:31

Mars_B4_Moon
Member
Registered: 2006-03-23
Posts: 9,267

Re: Nuclear power is safe

Nuclear fusion will not be regulated the same way as nuclear fission — a big win for the fusion industry
https://www.cnbc.com/2023/04/20/nuclear … on-is.html
The nation's top regulatory body for nuclear power plants and other nuclear materials, the Nuclear Regulatory Commission, has officially voted to regulate nuclear fusion differently than fission.

Elon Musk invited to testify in the European Parliament
https://www.politico.eu/article/elon-mu … arliament/

SpaceNut wrote:

"This is hugely disappointing, when a secure low carbon 24/7 source of energy such as nuclear was available and could have continued operation for another 40 years," Henry Preston, spokesperson for the World Nuclear Association, told CNBC. "Germany's nuclear industry has been world class. All three of those reactors shut down at the weekend performed extremely well."

Elon Musk Says Germany Is Making a Dangerous Mistake
https://www.thestreet.com/technology/el … us-mistake
Germany said goodbye to its last three nuclear reactors

Last edited by Mars_B4_Moon (2023-04-28 08:24:55)

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#555 2023-04-28 12:16:50

tahanson43206
Moderator
Registered: 2018-04-27
Posts: 17,104

Re: Nuclear power is safe

For Mars_B4_Moon re #554 and concern about Germany closing fission pathway.

I tried to find out what percentage of funding for ITER is coming from Germany, but was not successful in the first attempt.

The contribution by Germany is packaged inside the contribution by Europe (28 nations).

This is just a guess, but perhaps German leaders are betting heavily on fusion, and are willing to take a hit by dropping fission as a technology.

Elon should know about dangerous mistakes ... launching Starship-Heavy without a water deluge was one of his bigger ones.

(th)

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#556 2023-04-29 10:29:20

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 28,858

Re: Nuclear power is safe

I saw recently that a plant that was not active was being reactivated in the US of which the double price increase for my state aired news that its beyond the providers to control what they charge to the customer.

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#557 2023-04-29 10:59:59

tahanson43206
Moderator
Registered: 2018-04-27
Posts: 17,104

Re: Nuclear power is safe

For SpaceNut re #556

Thanks for a reminder of regulatory agencies that control prices charged by utilities in some States.

It sounds as though your State has such an agency.

The purpose of such an agency ** should ** be to try to find a middle course that allows the utility to cover expenses and make a modest profit, while at the same time keeping prices as low as possible for the citizens.

It should be possible for you to discover meeting transcripts and reports of studies, to satisfy yourself that your agency is steering the optimum course. Please note that such an agency needs to plan for the future as well as meeting immediate needs, and ** that ** means they should be forcing savings to cover the expenses that will inevitably occur.

We have such an agency in my State, and something quite remarkable just happened... We have an option to spread payments over a period of time, such as half a year, and I am used to having to pay a bit more than usual at settle time, or occasionally my monthly bill is reduced to make up for overpayment. However, I can't recall ** ever ** having had a payment set to zero, as just happened.

This topic is Nuclear Power is Safe.

To return the topic to it's purpose, I would hope that there are regulatory agencies supervising all nuclear plants in the US, and that they too are attempting to manage the operation of the plants and the charges to consumers to sustain the systems over the long term, while affording a modest return to investors.

(th)

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#558 2023-05-02 12:58:39

tahanson43206
Moderator
Registered: 2018-04-27
Posts: 17,104

Re: Nuclear power is safe

https://www.yahoo.com/autos/could-compa … 00969.html

This is another take on SMR and Idaho National Laboratory

Could Compact Nuclear Reactors Be the Future of Electricity?
38
Steve DaSilva
Mon, May 1, 2023 at 4:00 PM EDT

Photo: DANIEL LEAL/AFP (Getty Images)

Nuclear power is clean, efficient, and safe, yet it’s vastly underutilized as a method of generating electricity. Sure, people have their fears about Chernobyl or Fukushima, but those don’t align with the data — statistically, you’re more likely to die in a wind turbine accident. So why don’t we use more nuclear energy?

The reasons, for the most part, boil down to cost. Building generators is expensive, fuel is expensive, training a workforce is expensive. But researchers at the Idaho National Laboratory think they have a solution to all three: Make reactors smaller.

Vox has a great piece about the INL and its efforts to build compact, inexpensive nuclear reactors. Researchers hope that by making new reactors smaller, they can be deployed more easily, massively lowering the barrier to entry for clean power.

Reducing the footprint of a nuclear installation from acres to square feet is a monumental task, but INL researchers think they’ve found the solution: Heat. As nuclear reactors get hotter, they produce energy more efficiently, allowing for more power to come from a smaller footprint.

Of course, extra heat means extra cooling, something traditional liquid-based systems just can’t handle. To solve this, INL researchers turned to new coolants — think less about antifreeze, more about molten metal or salt. With stable cooling at these higher temperatures, compact reactors can even use cheaper fuels, making nuclear even more practical for use in grids.

Vox’s full explainer is worth a read, and the story of the INL’s nuclear research is worth following. If their tests pan out, you might just start reading Jalopnik by the power of a compact, local nuclear power grid.

More from Jalopnik

The link to the Vox report is:
https://www.vox.com/science/23702686/nu … ate-change

(th)

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#559 2023-05-05 08:43:18

Calliban
Member
From: Northern England, UK
Registered: 2019-08-18
Posts: 3,413

Re: Nuclear power is safe

Highly reliable stirling engines have been developed by NASA.
https://m.youtube.com/watch?v=chv6_seOa … FIAQ%3D%3D

One unit has been running continuously since 2003.  The NASA design has few moving parts and very little friction.  It is anticipated that these devices will replace Seebeck modules in RTGs.  Efficiency is ~20%, versus 6% for a Seebeck generator.  We could couple these units to liquid metal cooled fast reactors to produce highly compact nuclear power sources.  As the stirling generator is highly reliable and uses an inert gas as working fluid, we would not need the bulky double walled heat exchangers that are needed when sodium cooled reactors drive steam cycles.

Last edited by Calliban (2023-05-05 08:46:14)


"Plan and prepare for every possibility, and you will never act. It is nobler to have courage as we stumble into half the things we fear than to analyse every possible obstacle and begin nothing. Great things are achieved by embracing great dangers."

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#560 2023-05-05 09:47:21

Void
Member
Registered: 2011-12-29
Posts: 7,088

Re: Nuclear power is safe

I think that that is really a big thing.  While solar can be of importance on the Moon and Mars, it will be far better to have these power sources as well.

Done.


Done.

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#561 2023-05-05 09:57:17

Calliban
Member
From: Northern England, UK
Registered: 2019-08-18
Posts: 3,413

Re: Nuclear power is safe

A while back I discovered a reactor concept from early in the nuclear age: the liquid plutonium reactor.  Plutonium metal melts at 600°C.  This reactor concept works by forcing liquid sodium through a compact vessel of liquid plutonium metal, which is critical.  The low viscosity of sodium allows it to break into tiny droplets, that rise rapidly through the liquid plutonium and seperate on top by density, with liquid sodium having only 4% the density of plutonium.  The tiny sodium droplets are able to achieve 100x the heat transfer rate of heat from solid fuel into liquid sodium.  This design therefore allows enormous power density, on the order of 50GWth per cubic metre.

If we are able to produce power generation equipment that is maintenance free for decades, this affords a unique opportunity for a space based nuclear reactor.  Sodium can be replaced with liquid sodium rubidium alloy, as rubidium is completely miscible in liquid sodium.  At 1215K, rubidium vapour pressure is 10 bar(a).  The rubidium will boil in the core above the plutonium and will produce rubidium vapour.  The sodium has a higher vapour pressure and would therefore remain liquid.  Rubidium has an atomic weight of 85.5, which is nearly twice the molecular weight of CO2 and 5x the molecular weight of water.  A rubidium vapour turbine would be extremely compact and have a very high power density.  The boiling rubidium reactor therefore allows the combination of a very high power density reactor with a high power density turbine.

At 500°C, the vapour pressure of rubidium is 0.123bar(a).  This allows construction of a turbine with pressure ratio of 80.  At 500°C, a radiator can radiate 20kW of heat per square metre.  This is useful if your reactor is located on a spacecraft with tight mass budgets.  On Mars, we would pump the still hot rubidium out of the condenser and into a heat exchanger, allowing an S-CO2 cycle will generate more power.  For a spacecraft, a direct cycle boiling rubidium reactor offers unsurpassable power density.  The carnot efficiency of the cycle would be 36% between 1215K and 773K hot and cold temperatures.  If the compact power cycle can achieve around 3/4 of carnot efficiency, practical efficiency would be 27%.  In a combined cycle with S-CO2, we could achieve 56% efficiency, taking the S-CO2 efficiency to be 40% at a 500°C inlet temperature.  What the direct cycle lacks in efficiency it makes up for in raw power output.  With a reactor this power-dense, flying aircraft carriers would be possible.

Last edited by Calliban (2023-05-05 10:25:39)


"Plan and prepare for every possibility, and you will never act. It is nobler to have courage as we stumble into half the things we fear than to analyse every possible obstacle and begin nothing. Great things are achieved by embracing great dangers."

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#562 2023-05-05 16:42:53

kbd512
Administrator
Registered: 2015-01-02
Posts: 7,427

Re: Nuclear power is safe

Calliban,

We debated the correct materials to use for the thermal power source for our Earth-based thermal battery-powered vehicle.

How much shielding will a 40kWt core require to be able to walk right up to the edge of the outer mold line of the shielding?

I'm interested in supplying thermal power to a thermal-hydraulic drive system for an exploration vehicle that creeps along, sort of like NASA's crawler-transporter.  We need a low-speed vehicle for a crew of six, working in 8 hour shifts, to move around the planet continuously, prospecting for metals and minerals to mine.  It only needs to move fast enough to allow samples to be collected, as it attempts to locate and characterize the best resources for mines.  Top speed for this vehicle would be about 5km/hr over flat / open terrain.  Most of the time it's creeping along, permitting the crew enough time to collect or drill for samples, then return to the nuclear powered vehicle with their samples.

At 5km/hr, it can circle the planet almost 6.5 times per Earth standard year.  That's more than fast enough to do what I want it to do, which is to characterize what we find on the surface or top-most layer of regolith.

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#563 2023-05-05 17:20:19

Calliban
Member
From: Northern England, UK
Registered: 2019-08-18
Posts: 3,413

Re: Nuclear power is safe

We can get a first estimate of power requirement by calculating rolling resistance.  On Earth, car tires driving through sand have rolling resistance factor of 0.3.
https://en.m.wikipedia.org/wiki/Rolling_resistance

For each kg of vehicle mass on Mars, the required driving force to overcome rolling resistance will be:

F = W x Crr = 1 x 9.81 x 0.38 x 0.3 = 1.12N

Travelling at 5km/h (1.39m/s), the amount of mechanical power needed is:

P = F x v = 1.12 x 1.39 = 1.56W/kg.

If we take vehicle mass to be 10,000kg, then we need a minimum power output of 15.6kW to drive the vehicle.  With minimal hotel requirements, we can bump that up to 20kW.

Last edited by Calliban (2023-05-05 17:27:18)


"Plan and prepare for every possibility, and you will never act. It is nobler to have courage as we stumble into half the things we fear than to analyse every possible obstacle and begin nothing. Great things are achieved by embracing great dangers."

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#564 2023-05-05 21:38:20

kbd512
Administrator
Registered: 2015-01-02
Posts: 7,427

Re: Nuclear power is safe

Calliban,

50MWt/L?  That's pretty insane.  Is there a practical way to drag that figure down to a workable value for a land vehicle?

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#565 2023-05-08 09:15:07

tahanson43206
Moderator
Registered: 2018-04-27
Posts: 17,104

Re: Nuclear power is safe

https://www.yahoo.com/finance/news/bill … 21256.html

This article reports on (apparent) competition for SMR's in the UK

The Telegraph
Rolls-Royce mini-nukes project under threat as Bill Gates eyes bid

Gareth Corfield
Sun, May 7, 2023 at 12:38 PM EDT

Bill Gates - WPA Pool/Getty Images Europe
Bill Gates is eyeing a bid to build Britain’s first mini-nuclear reactor in a direct challenge to Rolls-Royce which is scrambling to secure a government contract.


Seattle-based TerraPower, which was founded by the Microsoft billionaire, said it was considering throwing its hat into the ring for lucrative contracts to build Britain’s next-generation small modular reactors or “mini-nukes”.

In a blog post, Mr Gates said the nuclear energy company’s work “has drawn interest from around the globe”, citing agreements with Japan, South Korea and the Luxembourg-based ArcelorMittal steel conglomerate.

TerraPower claims its travelling wave reactor design can “operate for centuries with unenriched uranium fuel”. Founded in 2006, the company secured $830m (£657m) in its most recent funding round last summer.

Unlike many traditional SMR designs, the company's plant, called Natrium, uses a molten salt heat storage system that will allow it to rapidly boost its power output at peak times.

TerraPower told the Sunday Times: “We are currently reviewing the opportunity [to deploy Natrium] in the UK. The UK has a lot to offer in the deployment of new nuclear technologies.”

Rolls-Royce is facing a battle to get its own SMRs approved by the Government after Chancellor Jeremy Hunt said that a competitive tender would be run on the projects, despite £210m of taxpayer money already having been invested in the company's proposal.


SMRs - Rolls-Royce

Kwasi Kwarteng, the then-business secretary, said at the time that the investment would help position Rolls-Royce “as a global leader in innovative nuclear technologies we can potentially export elsewhere”.

Last summer, the British engineering company appointed a new chief executive, Tufan Erginbilgic, who described the business as a “burning platform” that had to evolve or die.

In comments to staff he said: “Every investment we make, we destroy value”. In March, Mr Erginbilgic announced an overhaul of Rolls-Royce's top team which included the departure of Tom Samson, who has headed up the SMR division since its inception in 2020.

Rolls-Royce did not respond to a request for comment.

Dozens of other nuclear energy startups are competing to bring their designs into service, with Rolls-Royce competing against the likes of GE-Hitachi, Mitsubishi Heavy Industries and Westinghouse Electric.

In March, US company Last Energy, signed a deal to sell 24 small modular reactors (SMRs) to British customers.

While Last Energy still needs regulatory approval for its designs, the company expects the first of its SMRs to be operational by 2026 with no government funding required.

Broaden your horizons with award-winning British journalism. Try The Telegraph free for 1 month, then enjoy 1 year for just $9 with our US-exclusive offer.

(th)

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#566 2023-05-08 16:34:52

Calliban
Member
From: Northern England, UK
Registered: 2019-08-18
Posts: 3,413

Re: Nuclear power is safe

kbd512 wrote:

Calliban,

50MWt/L?  That's pretty insane.  Is there a practical way to drag that figure down to a workable value for a land vehicle?

Power can certainly be scaled down.  In fact, for very small devices, neutron leakage would tend to scale power down naturally.  The smallest possible reactor would have a core diameter 9.9cm.
https://en.m.wikipedia.org/wiki/Critical_mass

Liquid plutonium allows the highest possible fissile density and the most compact cores.  Thisbis advantageous for a vehicle, as shielding is also compact.  It is a proliferation nightmare.  But that doesn't seem to be a problem on Mars.

Last edited by Calliban (2023-05-08 16:36:17)


"Plan and prepare for every possibility, and you will never act. It is nobler to have courage as we stumble into half the things we fear than to analyse every possible obstacle and begin nothing. Great things are achieved by embracing great dangers."

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#567 2023-06-10 06:26:29

tahanson43206
Moderator
Registered: 2018-04-27
Posts: 17,104

Re: Nuclear power is safe

For Calliban ....

This is an inquiry that may be of interest...

Recent activity in the Thermal Battery topic includes consideration of carrying liquid air in a vehicle, and liberating mechanical force by elevating the temperature of the air molecules using a heat store.

A nuclear fission reactor is a viable alternative.

According to Google:

Semi truck engines are about six times larger than those found inside passenger cars. On average, semi truck horsepower ranges from 400 to 600 hp, while average lb-ft of torque ranges from 1,000 to 2,000.

Can you (would you) take a look at the scenario I am imagining, of a small reactor delivering 600 hp by heating liquid air?

The regime of temperatures would be on the low end of the scale, which might be attractive for a transportation application.

The effluent would be room temperature air, released after driving an air motor (or several of them, depending upon efficiency).

(th)

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#568 2023-06-13 21:14:11

Void
Member
Registered: 2011-12-29
Posts: 7,088

Re: Nuclear power is safe

I thought I would put this here.  I am not very informed bout nuclear, but it sounds good.

The part I like most is that they claim to be able to burn up old nuclear waste products and make the result much less a problem.

https://www.bing.com/videos/search?q=En … M%3DHDRSC4
Quote:

Energy Future Unveiled! THORIUM Molten Salt Reactors
YouTube2.8K views2 days agoby Copenhagen Atomics

I am an observer, I do not claim to know.

Done


Done.

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#569 2023-06-15 07:21:29

Calliban
Member
From: Northern England, UK
Registered: 2019-08-18
Posts: 3,413

Re: Nuclear power is safe

The reduced moderation boiling water reactor, is the technically easiest closed fuel cycle reactor system and is likely to be the first developed.
https://www.neimagazine.com/features/fe … e-of-lwrs/

The goal of a fuel conversion ratio of 1.0 will require large reactors with efficient neutron economy, high epithermal neutron spectrums and high enrichment of 20%.  A technically easier goal, would be reactors with increased conversion ratio of 0.8, with flourex or purex fuel reprocessing to close the fuel cycle.

In a standard enrichment cycle, 5% enriched fuel is produced by taking natural uranium hexafluoride (0.71% enriched), producing 5% enriched fuel and producing tailings with enrichment of 0.3%.  For each kg of enriched fuel we need 12.2kg of natural uranium and produce 11.2kg of tailings.  The discharged fuel will contain 1% 235U and 1% Pu and other actinides.  Some 4% of the fuel mass is fissioned and only 0.33% of the original uranium mass is fissioned.

In the RBWR cycle, with a conversion ratio of 0.8, to produce 1kg of 5% enriched fuel, we begin with 0.96kg of uranium that has been enriched from 0.71% to 1.0%.  We then add 0.04kg of plutonium and higher actinides extracted from used fuel.  To produce 0.96kg of 1.0% enriched uranium, we need 1.64kg of natural uranium and produce some 0.68kg of tailings.  Total uranium consumption for a closed fuel cycle, burning MOX with a conversion ratio of 0.8, reduces uranium consumption by a factor of 7.4.  At discharge, some 4% of fuel is fissioned and 2.4% of the original uranium mass is fissioned.  Tailings mass is reduced by a factor of 16.5.

This innovation would therefore substantially improve the sustainability of nuclear power from a fuel supply perspective and would also reduce the production of long-lived nuclear waste by recycling long-lived actinides back into the fuel.  Unlike the sodium cooled fast neutron reactor, all of the technology needed to make this work is already developed.

Last edited by Calliban (2023-06-15 07:24:41)


"Plan and prepare for every possibility, and you will never act. It is nobler to have courage as we stumble into half the things we fear than to analyse every possible obstacle and begin nothing. Great things are achieved by embracing great dangers."

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#570 2023-06-15 08:38:03

tahanson43206
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Registered: 2018-04-27
Posts: 17,104

Re: Nuclear power is safe

For Calliban re Post #569

Thanks for the details and comparisons you provided, in support of a concept that ( I understand ) burns radioactive materials produced by prior power generation runs.  I am guessing that chemical processes may be used to separate isotopes from the used materials, but mechanical processes may be required as well.

Can you (would you) describe the support processes that would permit continuous operation of this facility?  Can the entire operation be performed in a single facility?  I'm offering that suggestion in support of security requirements for what would clearly be a national asset.

The opportunity to replace ground sourced hydrocarbons with ones made from air and water remains "out there" for an ambitious nation willing to take the risks.

(th)

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#571 2023-06-17 12:29:47

tahanson43206
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Registered: 2018-04-27
Posts: 17,104

Re: Nuclear power is safe

Here's an article that fits the theme of this topic...

https://www.yahoo.com/news/report-shows … 00462.html


Lajja Mistry

Sat, June 17, 2023 at 9:00 AM EDT

A 2022 report by the U.S. Department of Energy (DOE) shows that 80% of the country’s retired or active coal plants are suitable to host advanced nuclear reactors.

The team identified 157 retired coal plant sites and 237 operating coal plant sites that can undergo a coal-to-nuclear transition. This could lead to many new employment opportunities, increasing economic benefits, and a significant improvement in nearby environmental conditions.

Nuclear energy is set to play a key role in meeting President Biden’s goals to achieve a clean grid by 2035 and reach net-zero carbon emissions by 2050. To pull that off, the DOE estimates that the country will need around 200 gigawatts of new nuclear power.

As of 2022, there were 92 nuclear power reactors in the U.S., most of which are on the East Coast or in the Midwest. And in 2021, nuclear power accounted for around 19% of energy produced in the U.S.



“Advanced nuclear will become an increasingly important source of safe, reliable, and flexible baseload power as the nation decarbonizes its energy systems,” Jigar Shah, director of the Loan Programs Office at the U.S. Department of Energy, shared in a LinkedIn post.

“Advanced nuclear, along with other firm and flexible energy sources, will help ensure there is reliable and affordable energy on a modern, decarbonized grid,” he added.

Some critics question the use of nuclear energy to solve climate problems, partially due to costs, risks, and radioactive wastes. Meanwhile, the Nuclear Energy Institute claims that advanced nuclear reactors “will offer a variety of benefits such as water desalination, process heat and alternative fuels generation, and access to power beyond the grid.” It adds, “Advanced reactors represent the cutting edge in nuclear technology: many are inherently safer by design.”

The 2022 report found that a coal-to-nuclear transition could reduce carbon pollution in nearby areas by 86%, which, according to the DOE, is “equivalent to taking more than 500,000 gasoline-powered passenger vehicles off the roads.”

“This is an important opportunity to help communities around the country preserve jobs, increase tax revenue, and improve air quality,” Assistant Secretary for Nuclear Energy Dr. Kathryn Huff said in a press release shared by the DOE. “As we move to a clean energy future, we need to deliver place-based solutions and ensure an equitable energy transition that does not leave communities behind.”

Join our free newsletter for cool news and actionable info that makes it easy to help yourself while helping the planet.

(th)

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#572 2023-06-27 06:25:34

Calliban
Member
From: Northern England, UK
Registered: 2019-08-18
Posts: 3,413

Re: Nuclear power is safe

Sweden drops nuclear phase-out policy and announces a 'fossil-free' energy aspiration.  This allows new nuclear power plants to be considered alongside renewables as an option for reducing fossil fuel reliance.
https://www.zerohedge.com/energy/sweden … lear-power


"Plan and prepare for every possibility, and you will never act. It is nobler to have courage as we stumble into half the things we fear than to analyse every possible obstacle and begin nothing. Great things are achieved by embracing great dangers."

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#573 2023-07-06 06:28:19

tahanson43206
Moderator
Registered: 2018-04-27
Posts: 17,104

Re: Nuclear power is safe

Canada announces plans to initiate a study to expand an existing nuclear power plant ...

Bloomberg
World’s Biggest Nuclear Power Plant Being Planned in Canada

1
Will Wade
Wed, July 5, 2023, 1:40 PM EDT
(Bloomberg) -- A Canadian utility is starting early work to expand a nuclear plant, potentially building the world’s biggest facility as growing demand for clean energy spurs interest in atomic energy.

The Ontario government said Wednesday Bruce Power will conduct an environmental assessment of adding as much as 4.8 gigawatts of capacity to its plant in Canada’s most-populous province. The plant’s eight reactors currently have about 6.2 gigawatts of capacity and supply 30% of the province’s power.

The expansion would make the site larger than Japan’s Kashiwazaki-Kariwa plant, the biggest in the world with seven reactors and more than 8 gigawatts of capacity.

The announcement comes amid growing recognition that carbon-free nuclear power is likely to play an important role in the global battle against climate change. Canada is developing plans to mandate a net-zero power grid by 2035, and the Bruce project would be the first conventional nuclear plant in the province in three decades. Another utility in the region, Ontario Power Generation Inc., is involved in an effort to develop a new type of advanced reactor.

“New nuclear generation is going to be critical to building the clean grid of the future,” said Todd Smith, Ontario’s energy minister.

(th)

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#574 2023-07-11 14:03:07

tahanson43206
Moderator
Registered: 2018-04-27
Posts: 17,104

Re: Nuclear power is safe

This is for Calliban and everyone is welcome to pitch in ...

kbd512 just posted an analysis of energy needs and possible solutions.

Among the points delivered in the post is one about the number of nuclear reactors that would meet current needs...

http://newmars.com/forums/viewtopic.php … 93#p211893

My question is .... is there any way to estimate how long a modern reactor (light water or otherwise) would run if one of the nuclear bombs we humans have built up over the past decades could be reassigned to reactor duty?  Is it practical to put such highly enriched material into civilian service?

(th)

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#575 2023-07-11 15:58:39

kbd512
Administrator
Registered: 2015-01-02
Posts: 7,427

Re: Nuclear power is safe

tahanson43206,

The US already mixes in the Plutonium from old demilitarized nuclear warheads, into fresh reactor fuel, and has done so for many years now.  Other nuclear armed nations have done the same thing.  It's one way to prove destruction of the warheads.  After the material is thoroughly mixed, it's no longer considered weapons grade material, just plain old reactor fuel.

Edit:
Once the mixed fuel enters the reactor, it's no longer separable for all practical purposes.  Think about what a reactor does.  It irradiates the fertile material and makes new fuel (fissile isotopes) as it runs.  Pu-239 from demilitarized warheads, exposed to the conditions inside an operating reactor for longer than a specified period of time, will either fission or transmute into other heavier elements like Pu-240, a hard gamma emitter, and then your hopes of recovering the Pu-239 inputs are pretty much nonexistent.

The quantity of Pu-239 present in any given pellet of fuel is like the dust covering a boulder.  The dust is obviously still there, but the mass of the boulder is well in excess of the mass of dust.

Can you "get the Plutonium out" if money and time is no object?  Sure, but anyone with a reactor can make Pu-239 if they really want to, because U-238 (the fertile but not fissile material, and also the vast majority of the material, will inevitably become Pu-239 at some point during the fuel burn.  It's the same level of difficulty at that point as just making a nuclear weapon from scratch.

Last edited by kbd512 (2023-07-11 16:11:36)

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