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 Post subject: LFTR vs ESBWR
PostPosted: Nov 04, 2013 10:54 pm 
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I was curious, LFTR vs ESBWR

search.php?st=0&sk=t&sd=d&sr=posts&keywords=ESBWR

I don't know the comparisons. I want to know more!

TEACH ME!


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 Post subject: Re: LFTR vs ESBWR
PostPosted: Nov 04, 2013 11:05 pm 
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Apples vs Aardvarks? Totally different? What do you want compared?

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 Post subject: Re: LFTR vs ESBWR
PostPosted: Nov 04, 2013 11:09 pm 
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capital costs?
electricty generation vs process heat?
fuel costs?
"proliferation"?
safety?
how easily scaled to make more energy?
energy density?


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 Post subject: Re: LFTR vs ESBWR
PostPosted: Nov 05, 2013 1:18 pm 
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Capital cost, strictly lower for ESBWR because it has far fewer components and mostly at low temperare. LFTR has more equipment. Primary loop of LFTR is at low pressure, but that is likely offset by the greater complexity of a LFTR, and more expensive high temperature materials. There are at least 3 loops whereas ESBWR has just one. LFTR loops are thinner but use more expensive materials than the cheap steels used in pressure vessels of LWRs. More or less offsetting. LFTR doesn't need a pressurized containment, but on the other hand the containment demand on the reactor vessel and primary loop are extreme. They must keep in all the nasty volatile fission products and do so at very high temperature, during normal operation. ESBWR primary loop has neither operational requirement.

Fuel cycle cost, likely somewhat lower for LFTR, but fuel cycle cost isn't a major cost for any nuclear powerplant.

Ditto for proliferation, there are some advantages with thorium cycles, but power reactors are not a proliferation threat in the first place. It's kind of like asking, which is more dangerous, a piece of straw of a leaf. Silly question, neither are likely to kill you, unless you have a very active imagination.

Ditto for long lived nuclear waste. That's more like worrying about the danger of a parked car. How many people are killed every year by parked cars? Moving cars are very dangerous, killing over a million people a year. Fresh spent fuel also seems dangerous, though it actually kills 0 people a year unlike moving cars. Old spent fuel isn't dangerous, much like the parked car, though truth be told it can hardly get safer than 0 deaths a year that fresh spent fuel gets. Again people with over active imaginations can come up with a scenario where you somehow crash into a parked car and kill yourself, though it does not follow that parked cars are dangerous. One requires a lot more imagination still to get a casualty from old spent fuel than a casualty from a parked car. Parked cars, after all, are ubiquitous, whereas old spent fuel is not.

Not sure if any comparison between ESBWR and LFTR is valid though. ESBWR is a Gen III+ design, LFTR is at best a Gen IV design, maybe more like Gen V (category doesn't even exist yet). It's an almost licensed, mostly engineered design versus a future hypothetical design that isn't even in the conceptual design stage right now.

Also ESBWR is for large baseload electrical markets. It has economy of scale and economy of simplicity, but the downside is that it must compete with the biggest, cheapest coal plants. Practical molten salt reactor development programs will focus initially on smaller reactors for higher value markets, where the competition is not a big cheap coal plant but expensive fossil fuel that has to be hauled in from a great distance (remote power and process heat markets).

I believe there is a major synergy between LWRs and MSRs. The LWRs can displace coal now, which is good regardless. While doing it they make good startup fuel for LFTRs.

That line of argument allows us to displace lots of existing coal plants and even more coal later on in the form of startup fuel for MSRs that displace future coal plants.

It's a win-win situation, to use a populistic quote.


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 Post subject: Re: LFTR vs ESBWR
PostPosted: Nov 08, 2013 4:13 pm 
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Cyril R wrote:
Capital cost, strictly lower for ESBWR because it has far fewer components and mostly at low temperare. LFTR has more equipment. Primary loop of LFTR is at low pressure, but that is likely offset by the greater complexity of a LFTR, and more expensive high temperature materials. There are at least 3 loops whereas ESBWR has just one. LFTR loops are thinner but use more expensive materials than the cheap steels used in pressure vessels of LWRs. More or less offsetting. LFTR doesn't need a pressurized containment, but on the other hand the containment demand on the reactor vessel and primary loop are extreme. They must keep in all the nasty volatile fission products and do so at very high temperature, during normal operation. ESBWR primary loop has neither operational requirement.

Fuel cycle cost, likely somewhat lower for LFTR, but fuel cycle cost isn't a major cost for any nuclear powerplant.

Ditto for proliferation, there are some advantages with thorium cycles, but power reactors are not a proliferation threat in the first place. It's kind of like asking, which is more dangerous, a piece of straw of a leaf. Silly question, neither are likely to kill you, unless you have a very active imagination.

Ditto for long lived nuclear waste. That's more like worrying about the danger of a parked car. How many people are killed every year by parked cars? Moving cars are very dangerous, killing over a million people a year. Fresh spent fuel also seems dangerous, though it actually kills 0 people a year unlike moving cars. Old spent fuel isn't dangerous, much like the parked car, though truth be told it can hardly get safer than 0 deaths a year that fresh spent fuel gets. Again people with over active imaginations can come up with a scenario where you somehow crash into a parked car and kill yourself, though it does not follow that parked cars are dangerous. One requires a lot more imagination still to get a casualty from old spent fuel than a casualty from a parked car. Parked cars, after all, are ubiquitous, whereas old spent fuel is not.

Not sure if any comparison between ESBWR and LFTR is valid though. ESBWR is a Gen III+ design, LFTR is at best a Gen IV design, maybe more like Gen V (category doesn't even exist yet). It's an almost licensed, mostly engineered design versus a future hypothetical design that isn't even in the conceptual design stage right now.

Also ESBWR is for large baseload electrical markets. It has economy of scale and economy of simplicity, but the downside is that it must compete with the biggest, cheapest coal plants. Practical molten salt reactor development programs will focus initially on smaller reactors for higher value markets, where the competition is not a big cheap coal plant but expensive fossil fuel that has to be hauled in from a great distance (remote power and process heat markets).

I believe there is a major synergy between LWRs and MSRs. The LWRs can displace coal now, which is good regardless. While doing it they make good startup fuel for LFTRs.

That line of argument allows us to displace lots of existing coal plants and even more coal later on in the form of startup fuel for MSRs that displace future coal plants.

It's a win-win situation, to use a populistic quote.



Ever saw a post so well written, you had no idea how to reply, and it took you a few days ?
this is that post

i was somewhat afraid that bwr and lftr were competitor, but i am happy you point out they can coexist really well to replace coal. I also like the parked car analogy for nuclear "Waste". parked cars are not the danger.


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 Post subject: Re: LFTR vs ESBWR
PostPosted: Nov 09, 2013 6:15 pm 
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I agree, excellent post Cyril.

I think all the pieces are coming together for a replacement for coal in the next few decades, it's just going to take some re-educating of people of the real cost/benefit facts when it comes to nuclear vs. fossil fuels.


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 Post subject: Re: LFTR vs ESBWR
PostPosted: Nov 09, 2013 11:47 pm 
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In essence it appears that an LFTR will be hard pressed to match an ESBWR at turning out electricity or doing what LWRs are best at: producing vast amounts of saturated steam in the ~280C range, which is useful for various industrial purposes that don't require the searing heat that fossil fired boilers are capable of.

The more esoteric heat requirements such as for heating cracking plants or the bottoms boilers in atmospheric distillation plants will require the higher temperature of other types of reactors. (Although you can still boil off all the low-boiling fractions from crude oil at 280C, reducing the requirement for high temperature heat to boil the remainder).


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 Post subject: Re: LFTR vs ESBWR
PostPosted: Nov 10, 2013 4:58 am 
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E Ireland wrote:
In essence it appears that an LFTR will be hard pressed to match an ESBWR at turning out electricity or doing what LWRs are best at: producing vast amounts of saturated steam in the ~280C range, which is useful for various industrial purposes that don't require the searing heat that fossil fired boilers are capable of.

The more esoteric heat requirements such as for heating cracking plants or the bottoms boilers in atmospheric distillation plants will require the higher temperature of other types of reactors. (Although you can still boil off all the low-boiling fractions from crude oil at 280C, reducing the requirement for high temperature heat to boil the remainder).


Agree, though the ESBWRs thermal capacity is too large for most of the process heat market. 4500 MWth is pretty serious, even for a large industrial user.

Now, if you get higher temperature steam, then you get more options. You can generate more power and still get a high temperature for process heat in cogen mode. With ESBWR the steam temperature exiting the high pressure steam turbine is too low for most process heat applications, it is already pretty cold and saturated before it enters the high pressure turbine. District heating may be a market for a few ESBWRs, where you send the steam from the high pressure turbine to district heating, but this will only be suitable for a few of the world's biggest cities (biggest district heating networks are around 1300-1400 MWth or so).

Joule for joule, the highest value applications in process heat are at higher temperatures.


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 Post subject: Re: LFTR vs ESBWR
PostPosted: Nov 10, 2013 3:17 pm 
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Cyril R wrote:
E Ireland wrote:
In essence it appears that an LFTR will be hard pressed to match an ESBWR at turning out electricity or doing what LWRs are best at: producing vast amounts of saturated steam in the ~280C range, which is useful for various industrial purposes that don't require the searing heat that fossil fired boilers are capable of.

The more esoteric heat requirements such as for heating cracking plants or the bottoms boilers in atmospheric distillation plants will require the higher temperature of other types of reactors. (Although you can still boil off all the low-boiling fractions from crude oil at 280C, reducing the requirement for high temperature heat to boil the remainder).


Agree, though the ESBWRs thermal capacity is too large for most of the process heat market. 4500 MWth is pretty serious, even for a large industrial user.

Now, if you get higher temperature steam, then you get more options. You can generate more power and still get a high temperature for process heat in cogen mode. With ESBWR the steam temperature exiting the high pressure steam turbine is too low for most process heat applications, it is already pretty cold and saturated before it enters the high pressure turbine. District heating may be a market for a few ESBWRs, where you send the steam from the high pressure turbine to district heating, but this will only be suitable for a few of the world's biggest cities (biggest district heating networks are around 1300-1400 MWth or so).

Joule for joule, the highest value applications in process heat are at higher temperatures.


The Components of Process Heating Systems

For many industrial applications, 15%-85% of the energy supplied is used for heating the materials. Many factors, such as process temperature, equipment design and operation, and the type of heat recovery systems used, determine the energy effi- ciency of a process heating system. Hence, industrial process heating systems offer op- portunities to save significant amounts of energy. Process Heating Energy Consumption Process heating equipment is operated over a broad temperature range, from 300°F to as high as 3000°F. Consequently, these processes consume large amounts of energy. In fact, energy costs for process heating represent 2%–15% of a product’s total cost. In U.S. industry, process heating accounts for more direct energy use than any other processes that consume energy during manufacturing. Other energy consuming operations, such as steam http://www1.eere.energy.gov/manufacturi ... igpict.pdf

There seems to be a pretty big market for cheaper process heat, and I am guessing a key point for any country's industries..


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 Post subject: Re: LFTR vs ESBWR
PostPosted: Nov 10, 2013 3:44 pm 
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A nuclear safety engineer posted this BWR, ABWR, ESBWR and nuclear safety PDF for me on another forum, enjoy.

http://www.ansn-elibrary.org/images/c/c ... _Plant.pdf


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 Post subject: Re: LFTR vs ESBWR
PostPosted: Nov 11, 2013 9:45 am 
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Location: Calgary, Alberta
Very nice, thanks.


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 Post subject: Re: LFTR vs ESBWR
PostPosted: Nov 16, 2013 3:53 pm 
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Joined: Oct 28, 2013 12:24 am
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Hello everyone, I am new here, I am not a specialist in nuclear engineering so I apologize if I ask dumb questions.

You are talking about the ESBWR and I have a question about its safety.

Does the passive safety systems of the ESBWR require high pressure to work ?

I mean the condensers in the IC pools and the PCCS pools need high density steam to be efficient, right ?

If you have a hole or a failure in your containment, can you lose you containment's water inventory and the efficiency of your passive safety ?

Can someone explain me please ?

Thanks.


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 Post subject: Re: LFTR vs ESBWR
PostPosted: Nov 16, 2013 4:11 pm 
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Hi fab,

I'm not a professional either but there may be answer here on this PDF, page 32 has the passive safety system for the ESBWR.

http://www.ansn-elibrary.org/images/c/c ... _Plant.pdf

Quote:
This is also based on the gravity driven cooling system (GDCS) shown in Figure 23, which
are pools above the vessel that when very low water level is detected in the reactor, the
depressurization system opens several very large valves to reduce vessel pressure and finally
to allow these GDCS pools to reflood the vessel.


Hope that helps.


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 Post subject: Re: LFTR vs ESBWR
PostPosted: Nov 16, 2013 4:51 pm 
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Thank you DougC, I will try to better understand the hydraulic schemes.


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 Post subject: Re: LFTR vs ESBWR
PostPosted: Nov 16, 2013 5:19 pm 
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The ESBWR has two type of passive safety cooling systems, the high pressure system and the low pressure one.

The high pressure system can cool the core when the reactor is pressurized. These are the normal cooling systems and the emergency isolation condensers.

The low pressure system can inject cooling water to the core when the reactor is at low pressure (after a pipe break). This is the GDCS system.

Longer term, after a pipe break, the heat must be removed from the containment. This is done with PCCS. The PCCS does require some containment pressure so if there's a hole in the containment it won't cool optimally. However quite a bit of water is present in the GDCS and before that is boiled away and leaked through the containment requires a lot of time.

Without a pipe break there is no need for containment integrity. No steaming in the containment occurs. It occurs in the isolation condenser water pool.

So you can have either a hole in the containment, or a hole in the vessel. If you have both then some operator action to add makeup water will be needed, to prevent core damage, though many hours are available to do this.


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