Fast breeder reactors

[Moreno]

4 minutes ago, Outrider said:

So now can I see the solid state reactor or maybe you know we could get back to fast breeders.

I suggested a possibility that fast neutron reactors can be made solid state. For now no such reactor exist.

[swansont]

12 hours ago, Moreno said:

I think that at the present and near future level of technology solar and wind power can be regarded only as a supplemental type of power generation only. First of all, Sun and wind are intermittent and if more than 50% of power will be generated in this way, this intermittence may lead to an unpredictable, possibly even catastrophic consequences.

Storage technologies exist, and are being improved.

12 hours ago, Moreno said:

Secondly, it requires too much expensive and sometimes rare materials. 

The implication here being that it's expensive? Solar and wind are the cheapest forms of energy generation in some places.

12 hours ago, Moreno said:

A typical nuclear power plant has 1 GWt output. Usually it includes a few nuclear reactors. And here is the size of a wind turbine which allows to generate just 10 MW of energy.

You could at least compare the electrical output of a nuke plant if you are going to cite the electrical output of a wind turbine. if you are going to compare, do it apples-to-apples.

You forgot to mention that, just like wind and solar, you can't put a nuclear power plant just anywhere. It needs water cooling, which has an environmental impact.  

9 hours ago, Moreno said:

I suggested a possibility that fast neutron reactors can be made solid state. For now no such reactor exist.

But not any hint as to how, making it indistinguishable from just throwing buzzwords around.

13 hours ago, Outrider said:

 Nuclear reactors are high reward/high risk operations. High reward because the energy generated is very clean (disregarding spent fuel*) and practically "free" for us and I mean free in the renewable sense. That is if everything works properly. High risk because if something does go wrong you will almost certainly have killed most of the people in the plant and possibly many persons, plants and animals in the surrounding area. Also in worse case scenario you might have made 100's of miles of viable land uninhabitable by us and most other organisms. 

That makes them high impact, rather than high risk. Risk tells you the chance something will go wrong. For every X number of hours of operation, you will get a major incident. The impact of a wind turbine failing, or even a dozen failures, is a lot smaller than the impact of a nuclear power plant failure like we've seen at Chernobyl and Fukushima.

[Moreno]

8 minutes ago, swansont said:

 But not any hint as to how, making it indistinguishable from just throwing buzzwords around.

I've already mentioned how. Some substances, such as boron-10 are capable to capture neutrons, convert to Lithium and radiate protons. Proton radiation subsequently can be easily converted to electricity with help of electrostatic converter. In this way no liquid or gaseous heat carrier is needed, potentially.

[swansont]

Just now, Moreno said:

I've already mentioned how. Some substances, such as boron-10 are capable to capture neutrons, convert to Lithium and radiate protons. Proton radiation subsequently can be easily converted to electricity with help of electrostatic converter. In this way no liquid or gaseous heat carrier is needed, potentially.

How is that solid-state?

[Moreno]

1 hour ago, swansont said:

How is that solid-state?

No macroscopic quantities of liquid or gas inside of reactor is needed.

[swansont]

19 minutes ago, Moreno said:

No macroscopic quantities of liquid or gas inside of reactor is needed.

That's not what solid-state means. Solid-state means it involves a semiconductor. As I said before, this is interaction at the atomic level.

 

[studiot]

27 minutes ago, swansont said:

That's not what solid-state means. Solid-state means it involves a semiconductor. As I said before, this is interaction at the atomic level.

 

 

In fairness to Moreno, that is not what he said.

Quote

Can there be an all-solid state reactors?

 

I took this to mean that there was no fluids in the reactor in any capacity and that the above English was just the sort of poor typing I might (and too often do) make.

Moreno repeated the phrase solid state, without the hyphen in a subsequent post.

 

[Endy0816]

There's thermoelectric generators.

https://en.m.wikipedia.org/wiki/Thermoelectric_generator

They can involve semiconductors, not sure if this is true for all types or not though.

Main issue looks to be the temperatures and efficiency. I have heard of a satelite using them, but not a plant.

https://en.m.wikipedia.org/wiki/Radioisotope_thermoelectric_generator

[Moreno]

1 hour ago, swansont said:

That's not what solid-state means. Solid-state means it involves a semiconductor. As I said before, this is interaction at the atomic level.

 

Not necessarily. For example this article describes a method of solid state refrigeration which doesn't involve a semiconductors. Word "solid state" in technics typically means there are no gases, liquids, or mechanicaly moving parts involved.

http://journals.sagepub.com/doi/abs/10.1243/0954406042369062?journalCode=picb

11 minutes ago, Endy0816 said:

Main issue looks to be the temperatures and efficiency. I have heard of a satelite using them, but not a plant.

https://en.m.wikipedia.org/wiki/Radioisotope_thermoelectric_generator

Direct charging generators[edit]

In the first type, the primary generator consists of a capacitor which is charged by the current of charged particles from a radioactive layer deposited on one of the electrodes. Spacing can be either vacuum or dielectric. Negatively charged beta particles or positively charged alpha particles, positrons or fission fragments may be utilized. Although this form of nuclear-electric generator dates back to 1913, few applications have been found in the past for the extremely low currents and inconveniently high voltages provided by direct charging generators. Oscillator/transformer systems are employed to reduce the voltages, then rectifiers are used to transform the AC power back to direct current.

English physicist H.G.J. Moseley constructed the first of these. Moseley’s apparatus consisted of a glass globe silvered on the inside with a radium emitter mounted on the tip of a wire at the center. The charged particles from the radium created a flow of electricity as they moved quickly from the radium to the inside surface of the sphere. As late as 1945 the Moseley model guided other efforts to build experimental batteries generating electricity from the emissions of radioactive elements.

https://en.wikipedia.org/wiki/Atomic_battery#Direct_charging_generators

 

Edited March 29, 2018 by Moreno

[studiot]

28 minutes ago, Moreno said:

Not necessarily. For example this article describes a method of solid state refrigeration which doesn't involve a semiconductors. Word "solid state" in technics typically means there are no gases, liquids, or mechanicaly moving parts involved.

If you want to get picky, then no that is not correct.

 

Firstly solid state is a phrase, not a word.

 

Then, of course, we have to look back in history to see when it was introduced and why.

The phrase 'solid state' (we do not use the american hyphen in England)  was introduced to distinguish between the all solid, no moving parts vacuum tube devices (valves in England) employing thermionic emission and the all solid state semiconductor based devices employing electrostatic potential barrier technology.

Further this was done as an advertising gimmick to promote the then new semiconductor diodes and transistors over valves.

However Scientifically, particually in Physics, the term coalesced during the mid 20th century by workers in many fields to include properties of mostly regular (ie crystalline) solids including, but not limited to, specific heat, optical properties, magnetic properties, electricla properties, crystal structure properties.

 

Better to have just explained exactly what you mean without a semantic sideshow.

Edited March 29, 2018 by studiot

[swansont]

30 minutes ago, Moreno said:

 Word "solid state" in technics typically means there are no gases, liquids, or mechanicaly moving parts involved.

This is posted in physics.  

9 minutes ago, studiot said:

 Better to have just explained exactly what you mean without a semantic sideshow.

This.

———

Now, here's the problem: how do you remove the heat from an all-solid reactor?

[studiot]

4 minutes ago, swansont said:

This.

———

Now, here's the problem: how do you remove the heat from an all-solid reactor?

I already asked that, but please also see the edit to my last post, added whilst you were posting the quote.

Edited March 29, 2018 by studiot

[Moontanman]

Are thorium molten salt reactors part of this thread or are they a different animal? 

[Moreno]

12 hours ago, Moontanman said:

Are thorium molten salt reactors part of this thread or are they a different animal? 

Sure, you can discuss them. Or any other kind of nuclear reactors. If I no make mistake LFTR's use thermal neutron spectrum rather than fast neutrons? What is bad about LFTR, I think, is they waste Lithium and Beryllium - a valuable metals. And other expenses are huge. I think accelerator driven reactors look more attractive.

[swansont]

2 hours ago, Moreno said:

Sure, you can discuss them. Or any other kind of nuclear reactors. If I no make mistake LFTR's use thermal neutron spectrum rather than fast neutrons? What is bad about LFTR, I think, is they waste Lithium and Beryllium - a valuable metals. And other expenses are huge. I think accelerator driven reactors look more attractive.

They waste Li and Be?

[Moreno]

38 minutes ago, swansont said:

They waste Li and Be?

FLiBe is a molten salt made from a mixture of lithium fluoride (LiF) and beryllium fluoride (BeF₂). It is both a nuclear reactor coolant and solvent for fertile or fissile material. It served both purposes in the Molten-Salt Reactor Experiment (MSRE).

https://en.wikipedia.org/wiki/FLiBe

During reactor operation Beryllium and Lithium are converted to other chemical elements by process of nuclear mutation, it seems.

[swansont]

18 minutes ago, Moreno said:

FLiBe is a molten salt made from a mixture of lithium fluoride (LiF) and beryllium fluoride (BeF₂). It is both a nuclear reactor coolant and solvent for fertile or fissile material. It served both purposes in the Molten-Salt Reactor Experiment (MSRE).

https://en.wikipedia.org/wiki/FLiBe

During reactor operation Beryllium and Lithium are converted to other chemical elements by process of nuclear mutation, it seems.

As is Uranium. But if they are part of making the reactor run, how are they "wasted"?

[Outrider]

On 3/29/2018 at 4:53 AM, swansont said:

That makes them high impact, rather than high risk. Risk tells you the chance something will go wrong. For every X number of hours of operation, you will get a major incident. The impact of a wind turbine failing, or even a dozen failures, is a lot smaller than the impact of a nuclear power plant failure like we've seen at Chernobyl and Fukushima.

Yes you are right nuclear power is actually low risk due to the safeguards put in place. 

On 3/29/2018 at 1:29 PM, Moontanman said:

Are thorium molten salt reactors part of this thread or are they a different animal? 

Yes MSR's are considered fast breeders. 

Quote

 

MSRs are walk-away safe. They cannot melt down as can conventional reactors because they are molten by design. An operator cannot even force an MSR to overheat. If for some reason an MSR were to overheat, the heat would melt a freeze-plug at the bottom of the reactor vessel and the liquid fuel salts would drain into the emergency cooling tanks where it would cool and solidify. No operator interaction nor even emergency backup power is needed for this to happen.

Even a human engineered breach (such as a terrorist attack) of an MSR cannot cause any significant release of radioactivity. The fuel salts for MSRs work at normal atmospheric pressure, so a breach of the reactor containment vessel would simply leak out the liquid fuel which would then solidify in as it cooled. 

 

Can anyone comment on the authenticity of the quote above?

 

[swansont]

That a MSR with molten fuel can't melt down is a semantic game. A meltdown is a concern because it represents a loss of containment. (and not all MSRs have molten fuel)

The claim here is that there is emergency cooling. Well, why wouldn't that protect other reactors? That's not something inherently safe about this design, it's a safety feature that's added.

Any reactor has to have decay heat removed. If you don't remove it, the reactor heats up. Whether that's a problem, or how much of a problem, depends on details.

The bit about "the fuel will solidify if there's a leak" glosses over multiple issues. Some fission products are gases, and decay heat means things might not solidify quickly.

[studiot]

Tectonic activity can defeat any safety measure or fail safe system.

 

[Outrider]

Here is the link for the quote 2 posts up.

https://www.zmescience.com/ecology/what-is-molten-salt-reactor-424343/

I forgot to add it earlier, sorry.

17 hours ago, swansont said:

That a MSR with molten fuel can't melt down is a semantic game. A meltdown is a concern because it represents a loss of containment. (and not all MSRs have molten fuel)

The claim here is that there is emergency cooling. Well, why wouldn't that protect other reactors? That's not something inherently safe about this design, it's a safety feature that's added.

Any reactor has to have decay heat removed. If you don't remove it, the reactor heats up. Whether that's a problem, or how much of a problem, depends on details.

The bit about "the fuel will solidify if there's a leak" glosses over multiple issues. Some fission products are gases, and decay heat means things might not solidify quickly.

I thought it sounded to good to be true. Thank you for your comments. Hopefully more later if I have the time.

[Moontanman]

19 hours ago, swansont said:

That a MSR with molten fuel can't melt down is a semantic game. A meltdown is a concern because it represents a loss of containment. (and not all MSRs have molten fuel)

The claim here is that there is emergency cooling. Well, why wouldn't that protect other reactors? That's not something inherently safe about this design, it's a safety feature that's added.

Any reactor has to have decay heat removed. If you don't remove it, the reactor heats up. Whether that's a problem, or how much of a problem, depends on details.

The bit about "the fuel will solidify if there's a leak" glosses over multiple issues. Some fission products are gases, and decay heat means things might not solidify quickly.

The cooling tanks are not filled with a coolant and are passive and ment to simply keep the Molten Salt from running all over the place. Without the "moderator" the Molten Salt solidifies on it's own. I would think that an Earthquake might allow groundwater to enter the building resulting in a bad reaction, not sure if it would explode. 

Quote

MSRs are walk-away safe. They cannot melt down as can conventional reactors because they are molten by design. An operator cannot even force an MSR to overheat. If for some reason an MSR were to overheat, the heat would melt a freeze-plug at the bottom of the reactor vessel and the liquid fuel salts would drain into the emergency cooling tanks where it would cool and solidify. No operator interaction nor even emergency backup power is needed for this to happen.

Even a human engineered breach (such as a terrorist attack) of an MSR cannot cause any significant release of radioactivity. The fuel salts for MSRs work at normal atmospheric pressure, so a breach of the reactor containment vessel would simply leak out the liquid fuel which would then solidify in as it cooled. 

In this particular example it is apparent they are talking about reactors that use molten salt. The terrorist attack quote seems a bit weak, if the terrorists managed to breach the core and spread moderator around with the MS then you would have a huge problem I am betting... 

[swansont]

1 hour ago, Moontanman said:

The cooling tanks are not filled with a coolant and are passive and ment to simply keep the Molten Salt from running all over the place. Without the "moderator" the Molten Salt solidifies on it's own. I would think that an Earthquake might allow groundwater to enter the building resulting in a bad reaction, not sure if it would explode. 

In this particular example it is apparent they are talking about reactors that use molten salt. The terrorist attack quote seems a bit weak, if the terrorists managed to breach the core and spread moderator around with the MS then you would have a huge problem I am betting... 

Moderators slow neutrons to facilitate fission. No moderator turns fission off, but the mixture is still going to contain all of the fission fragments, which are radioactive. Decay heat can be several percent of operating power. How fast will a bunch of molten salt cool when it's generating several MW of heat? (This is the problem that was faced by Fukushima - needing to cool both the reactor core and used fuel rods.)

 

[Moontanman]

5 hours ago, swansont said:

Moderators slow neutrons to facilitate fission. No moderator turns fission off, but the mixture is still going to contain all of the fission fragments, which are radioactive. Decay heat can be several percent of operating power. How fast will a bunch of molten salt cool when it's generating several MW of heat? (This is the problem that was faced by Fukushima - needing to cool both the reactor core and used fuel rods.)

 

You make a good point, of course the negatives aren't as stressed as the positives in the papers and videos I've seen and read. They do stress that the molten salt drained from the reactor does not support fission but they do not talk about the simple radioactive decay in the fission products. 

[swansont]

40 minutes ago, Moontanman said:

You make a good point, of course the negatives aren't as stressed as the positives in the papers and videos I've seen and read. They do stress that the molten salt drained from the reactor does not support fission but they do not talk about the simple radioactive decay in the fission products. 

There are some technical details that are glossed over or simplified to the point that they're wrong in the link.