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Toshiba 4S Reactors, Super Safe Small Simple





jwellsy
I don't want to derail the free electricity thread, so I'll start a new one on this Amazing Project.

Toshiba has been developing a small form factor standardized Advanced Boiling Water Reactor, a nuclear battery if you will. I think it's exciting.
http://www.toshiba.co.jp/nuclearenergy/english/

It's even attracting people like Bill Gates.
http://www.fastcompany.com/1594671/bill-gates-goes-nuclear-with-toshiba-tie-up

For a proof of concept project, Toshiba wants to donate a 10 MW version of the 4S to a remote town in Alaska called Galena. I think they also have designs for 50 and 100 MW versions.
http://en.wikipedia.org/wiki/Galena_Nuclear_Power_Plant

Quote:

The plant design is offered by a partnership that includes Toshiba and the Central Research Institute of Electric Power Industry (CRIEPI) of Japan.[1]

The technical specifications of the 4S reactor are unique in the nuclear industry.[citation needed] The actual reactor would be located in a sealed, cylindrical vault 30 m (98 ft) underground, while the building above ground would be 22 x 16 x 11 m (72 52.5 x 36 ft) in size. This power plant is designed to provide 10 megawatts of electrical power.[citation needed]

The 4S is a fast neutron reactor. It uses neutron reflector panels around the perimeter to maintain neutron density. These reflector panels replace complicated control rods, yet keep the ability to shut down the nuclear reaction in case of an emergency. Additionally, the Toshiba 4S utilizes liquid sodium as a coolant, allowing the reactor to operate 200 degrees hotter than if it used water. Using sodium allows the reactor to be unpressurized, even though water at this temperature would run at thousands of pounds per square inch.[citation needed]

The reactor is expected to provide electric energy for between 5 and 13 cents/kWh, factoring in only operating costs,[citation needed] to which unknown decommissioning and atomic waste processing and safe disposal costs need to be added. On paper, it has been determined[by whom?] that the reactor could run for 30 years without being refueled.[citation needed]

The Toshiba 4S Nuclear Battery is being proposed as the power source for the Galena Nuclear Power Plant in Galena, Alaska.[2] [3]
[edit]
Current developments

Currently Toshiba, together with its Westinghouse subsidiary, is in the preliminary design review stage of the Design Certification process before the USNRC.[4] Application for certification of the design is currently planned for 2012 when the standardized Design Certification application will be filed for the 4S. The most recent meeting with the NRC took place on August 8, 2008, at which time the NRC's staff met with representatives of Toshiba and Westinghouse for a pre-application presentation of a Phenomena Identification and Ranking Table (PIRT) for the Toshiba 4S (Super-Safe, Small and Simple) reactor. Lawrence Livermore National Laboratory recently released an interesting study on the Toshiba 4S design, which provides an overview of the 4S design and suggests that certain goals may be easier to meet if lead is used as the coolant rather than sodium, due to lead's high transparency to neutrons and low transparency to γ radiation, though lead has a higher melting point than sodium does.[5]

The NRC received the latest version of the letter of intent from the designers of the reactor as of March 13, 2009. The approval process is on track for official submission to the USNRC in October 2010 of a standard application for Design Certification. During the week of October 16, 2009, persons or organizations unknown submitted a Freedom of Information Act request to the USNRC requesting that "documents related to the Super-Safe, Small and Simple (4s) Nuclear Reactor from Toshiba Corporation particularly related to possible placement in Galena, Alaska, including tech info on reactor, safety assessments, nuclear material security, etc." be released to the requestors.[6]

http://en.wikipedia.org/wiki/Toshiba_4S


deanhills
jwellsy wrote:
The Toshiba 4S Nuclear Battery is being proposed as the power source for the Galena Nuclear Power Plant in Galena, Alaska.
I wonder why they decided to use a remote town in Alaska for this project? Smile
jwellsy
Yeah, and if they had to evacuate, where in the heck would they go?
10 MW isn't very much power either. You'd be lucky to power 50 homes with 10 MW.
Aulos
Depends on the amount of electricity consumed. In that Alaskan town, I think they're accustomed to not using much electricity in their houses. Not totally wired like my house.

What I find really great about this technology is the type of fuel it uses. This depleted uranium that would normally become waste could power the Earth for a very long time....
deanhills
Aulos wrote:
Depends on the amount of electricity consumed. In that Alaskan town, I think they're accustomed to not using much electricity in their houses. Not totally wired like my house.
Interesting thought. So do they then use gas-fired heating systems? How would the consumption be different from your house for example?
ocalhoun
deanhills wrote:
Aulos wrote:
Depends on the amount of electricity consumed. In that Alaskan town, I think they're accustomed to not using much electricity in their houses. Not totally wired like my house.
Interesting thought. So do they then use gas-fired heating systems? How would the consumption be different from your house for example?

Propane is more efficient for heating than electricity (and cheaper)... So it is likely many use that for heat... and of course, being Alaska, there isn't much need for air conditioning.

Given that, electric demand per household is probably less in Alaska than in other places.
Ghost900
Interesting, nuclear power testing. Hasn't the U.K. been using nuclear power for some time?

I would like to see nuclear power come to America so I think this is great news that they will be testing it even if it is in some backwoods in Alaska.
Nemesis234
jwellsy wrote:
Yeah, and if they had to evacuate, where in the heck would they go?
10 MW isn't very much power either. You'd be lucky to power 50 homes with 10 MW.


10mw - 50 homes? no way, thats like 200 kw per house? does one house often boil 200 kettles at once?

10mw should cover 3000 homes easy, and thats still plenty for each house to have tv,cooker,kettle,radio etc all on at the same time which is extremely unlikly
Bondings
It's a town of 612 people and they barely use electricity at the moment, so I guess it should be enough power for them.

From what I read about it in these links, this system seems really promising. It might even convince some opponents of nuclear energy as the danger and waste seem to be pretty much non-existing here.

But then again, there might be some practical problems or other issues that Toshiba didn't provide in their press releases and interviews. Wink
deanhills
Bondings wrote:
But then again, there might be some practical problems or other issues that Toshiba didn't provide in their press releases and interviews. Wink
Good point. Lately colleagues of mine have been improving their swearing vocabularly with regard to Toshiba laptops. Smile
ocalhoun
deanhills wrote:
Bondings wrote:
But then again, there might be some practical problems or other issues that Toshiba didn't provide in their press releases and interviews. Wink
Good point. Lately colleagues of mine have been improving their swearing vocabularly with regard to Toshiba laptops. Smile

^.^
Posting from a Toshiba laptop right now!
It has worked great for over two years... longer than my other laptops (a Dell and an IBM) lasted.

*end sidetrack*
mahirh
jwellsy wrote:
Yeah, and if they had to evacuate, where in the heck would they go?
10 MW isn't very much power either. You'd be lucky to power 50 homes with 10 MW.

but , for them living with some power is better than living with no power because , if they did adjust with no power for 50 years or longer , couldn't they survive with some power and good management because i don't think they even have money to buy a central heating setup or even stuff that could suck up more than 500 watts
misterXY
Ghost900 wrote:
Interesting, nuclear power testing. Hasn't the U.K. been using nuclear power for some time?

I would like to see nuclear power come to America so I think this is great news that they will be testing it even if it is in some backwoods in Alaska.

Don't the states have nuclear power..? Like in New Brunswick, Canada, LePearu (think l spelled it wrong) is a nuclear power plant, and l swear all the power it goes, it goes straight too the states.\

Watching CBC News ( Fifth Estate ) had a expert in nuclear power state that not a single nuclear power plant has ever made profit, and many of them are against renewable sources (just like the big oil companies). How many know of a nuclear plant near you (provincial, state, territory ask government for tax cuts etc..) Never have even broke even either! Too hell with nuclear.
dwxco
I really hope the project is successful, because it does open a lot of options (think neighborhood power reactor) that could easily be supplemented with other local power generation techniques. Where I live the sun is pretty intense, so solar + nuclear could go a long way to making our neighborhood energy independent.

But probably not in my lifetime. Hopefully solar on every rooftop in our part of the US will help drive down the cost of power.

http://en.wikipedia.org/wiki/World_energy_resources_and_consumption

This page has some information about energy sources and consumption.
jwellsy
I would like to hear more about the Emergency Core Cooling Systems.

The heart of most ECCS schemes is an Auto De-pressurization System that allows Low Pressure Coolant Injection systems to pump flooding quantities of water into the core.

There is an advanced BWR Design that that has large coolant storage tanks above the reactor and relies on gravity instead of pumps.

I wonder if they use a borated elevated annulus of Sodium as an ECCS?
matamlayin
Where I live the sun is pretty intense, so solar + nuclear could go a long way to making our neighborhood energy independent. The project was great and it amazed me so much...
matamlayin
Every energy supply we have has its pros and cons. The trick is finding one where the pros out stretch the cons. With current ways the cons are bigger than the pros sometimes. Look at oil currently. Just take a look at the gulf. The risk there is so massive and look at how it is hurting us all together. Its affecting our economy our food supply and so on. Is it really worth it. I think more time and money needs to be put into the research of better alternative methods. Cleaner Greener altternatives
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First frihost freak. How many people can say that?
First Directory listing. How many people can say that?
eday2010
ocalhoun wrote:
Propane is more efficient for heating than electricity (and cheaper)... So it is likely many use that for heat... and of course, being Alaska, there isn't much need for air conditioning.

Given that, electric demand per household is probably less in Alaska than in other places.


Nothing is more efficient than electricity for heating. 100% of the electricity is turned into heat. You don't get more efficient than 100%.
c'tair
Can't wait for those things. Man, they'd be awesome, a relatively cheap, safe, efficient way of getting electricity to areas where it's tough. I could even envision a whole matrix of these reactors powering a large city like NYC for example and when one would go offline then other's would fill in for it until it was replaced.

Of course, all of this will probably become swamped in politics and bureaucracy and I'm pretty much 100% sure that there are gonna be whistle blowers chaining themselves to trees and yelling "ZOMG U WANT TO BURY ATOMIC BOMB HERE AND KILL US ALL" so yeah...

Sorry for the cynicism Razz
SonLight
eday2010 wrote:


Nothing is more efficient than electricity for heating. 100% of the electricity is turned into heat. You don't get more efficient than 100%.


True, in a sense. All of the electrical energy can be turned into heat. Whether it is true for the whole system of both generating and using the electricity depends on how the electricity is generated.

If the electricity is generated from heat, as it is in a coal or nuclear plant for example, then there is an inefficiency in generating it. Heat engines, whether steam turbines or your automobile, are able to turn only part of the heat into motion or electricity; the rest is usually wasted and special provisions have to be made to remove it -- radiators and fans, cooling towers, or whatever. If natural gas is burned to produce heat, it will produce at least twice as much as the electricity produced by burning the same amount will. In some cases the part of the waste heat from an electric generation plant can be used directly for heating; this is called cogeneration and significantly increases the overall efficiency.

@c'tair, I hope this technology proves reliable and safe. It does need to be tested thoroughly however. If opponents try to prevent installation of demonstration projects they are being fools. On the other hand if the technology were rapidly deployed without enough testing for safety, someone would take shortcuts or there would be unexpected hazards, we would eventually have another serious incident like three mile island or Chernobyl, and after that no one would be willing to even consider the use of anything with the word NUCLEAR in it.
pll
Nobody talked about nuclear radiations.

Could this be dangerous for the human if some radiations would get out of this gadget ?
I think it's nice to find new ways to make energy but we need to take care of every little thing while doing that.
mahirh
pll wrote:
Nobody talked about nuclear radiations.

Could this be dangerous for the human if some radiations would get out of this gadget ?
I think it's nice to find new ways to make energy but we need to take care of every little thing while doing that.

well , 5 grams of uranium encased in lead isnt likely to cause any damage , but 5 grams is all what you need to run a full city
SonLight
mahirh wrote:

well , 5 grams of uranium encased in lead isnt likely to cause any damage , but 5 grams is all what you need to run a full city


I questioned the figure of 5 grams total amount of uranium, but couldn't easily find a reference for either the 4S reactor or for other reactors. In any case, production of 10MW of electricity (30MW thermal energy) over a period of several years is a __lot__ of energy, which would produce a lot of radiation as a waste product, which if released would be devastating.

Does anyone have a reference for the amount of fuel used, or a way to get a rough estimate?

edit:

Here's a clue, but it doesn't indicate the percentage of uranium in the fuel, and more calculation seems to be necessary.

Quote:
A rough estimate is that it takes 17,000 kilograms of coal to produce the same amount of electricity as 1 kilogram of nuclear uranium fuel.


http://library.thinkquest.org/17940/texts/fission_power/fission_power.html
mahirh
SonLight wrote:

I questioned the figure of 5 grams total amount of uranium, but couldn't easily find a reference for either the 4S reactor or for other reactors. In any case, production of 10MW of electricity (30MW thermal energy) over a period of several years is a __lot__ of energy, which would produce a lot of radiation as a waste product, which if released would be devastating.


anyways , you are going to release the wastes back into the catridge , moreover , the catridge is encased in lead and covered in air tight plastic , so i think there is no need to be worried about the radiation problem
the uranium needed to power up the whole thing maybe exaggerative because i read it in popular science a few years ago and a coal plant definitely produces radioactive emissions
and the calculation part , 17,000 kilograms of coal, so a light bulb which is on 24 hours a day (a 100 watt one)uses876 kWh so a coal plant takes 325 kg to power a light bulb for a year at 24/7 (if the bulb does last long enough to do that) so , (it may be wrong) , 1 kg of uranium alone can power 52.3076923 such bulbs for an year 24/7 without renewal
compared to coal which needs 17,000 kilograms to do that
but this number can vary if they use led bulbs or more efficient lighting technology

http://science.howstuffworks.com/environmental/energy/question481.htm wrote:
It also produces smaller amounts of just about every element on the periodic table, including the radioactive ones. In fact, a coal-burning power plant emits more radiation than a (properly functioning) nuclear power plant!
SonLight
OK, so it takes at least kilograms of fuel. I suspect the math is still not right, but I agree it's probably not mere grams. Of course there is no radiation problem, IF all the radiation stays inside the containment building as it's supposed to.

With any nuclear plant, there is a risk that a serious accident will release a lot of radiation very suddenly, killing or sickening anyone within a couple of miles. I am totally in favor of installing nuclear plants provided proper precautions are taken.

It appears the 4S plant has better safety features than most, so installing it makes a lot of sense. If experience and analysis shows the risks are as small as I believe they are, then installing a lot of others just like it makes a lot of sense. However, it is a small plant, and will not be economically competitive with large-scale plants for most applications. These plants can help us serve isolated areas, but for large cities we still need to find other solutions, nuclear or otherwise.

Large-scale nuclear plants probably cannot be designed to be as safe as this one, but they are probably safe enough that we should still consider installing more of them. We need to find the safest designs we can, and even then use them only as an interim solution. If we are still considering installation of nuclear fission plants or coal plants fifty years from now, it will probably be because we have failed to develop the greener technologies which our economy and the world need.
jwellsy
Uranium is only a small part of what's in a typical fuel pellet.

One class of nuclear fission byproducts are nuclear poisons. They absorb neutrons without causing a fission. This reduction factor in the the neutron population will increase over the life of the core as more and more of these poisons are formed. So more reactivity (uranium) as to be added to ensure that the poisons can be overcome near the end of core life.

This extra reactivity loading is also controlled by adding burnable poisons that are added to the fuel pellet. They absorb a neutron and then become inactive. These burnable poisons decrease over core life.

Fuel pellets are only about .5 inch diameter and about 1.25 inch long. These pellets then are stacked on top of each other in a long stainless steel tube. A spring is loaded inside the tube to keep the pellets from rattling around and the tube is then seal welded. several of these tube are put together in a tube bundle and hundreds of these bundles go in a core.

The % of uranium varies along the length of a fuel pin. You want an even neutron flux distribution over the core to prevent localized overpower excursions.

Uranium is only a small part of the entire working process equation.
ocalhoun
mahirh wrote:
SonLight wrote:

I questioned the figure of 5 grams total amount of uranium, but couldn't easily find a reference for either the 4S reactor or for other reactors. In any case, production of 10MW of electricity (30MW thermal energy) over a period of several years is a __lot__ of energy, which would produce a lot of radiation as a waste product, which if released would be devastating.


anyways , you are going to release the wastes back into the catridge , moreover , the catridge is encased in lead and covered in air tight plastic , so i think there is no need to be worried about the radiation problem
the uranium needed to power up the whole thing maybe exaggerative because i read it in popular science a few years ago and a coal plant definitely produces radioactive emissions
and the calculation part , 17,000 kilograms of coal, so a light bulb which is on 24 hours a day (a 100 watt one)uses876 kWh so a coal plant takes 325 kg to power a light bulb for a year at 24/7 (if the bulb does last long enough to do that) so , (it may be wrong) , 1 kg of uranium alone can power 52.3076923 such bulbs for an year 24/7 without renewal
compared to coal which needs 17,000 kilograms to do that
but this number can vary if they use led bulbs or more efficient lighting technology

http://science.howstuffworks.com/environmental/energy/question481.htm wrote:
It also produces smaller amounts of just about every element on the periodic table, including the radioactive ones. In fact, a coal-burning power plant emits more radiation than a (properly functioning) nuclear power plant!

so, 325kg of coal produces 876kwh of power...
and 325kg of uranium produces around 45,821kwh...
(876 x 52.3076923)
Therefore, 1kg of uranium produces about 140kwh.
So, 5g of uranium should produce 700wh. (Ignoring the whole critical mass issue.)

That pretty much invalidates the whole '5g could power a small town' estimate...
(I thought it sounded ridiculous, but I was too lazy to look up the numbers myself.)
I'm very frugal with electricity in my house, and I average only 250w per hour.
5g of uranium wouldn't power a small town; it could only power my small house for barely 3 hours.
SonLight
Thanks, jwellsy. What we needed was to hear from someone who actually understands this stuff. I was pretty sure 5 grams was too little, but I think the estimates mahirh and ocalhoun came up with (from my questionable data) sound way too high. Maybe it's somewhere near right if you take it as the weight of the whole fuel rod assembly.

I know this can be figured out based on the number of U235 atoms that have to be split to produce a given amount of heat, then consider the efficiency (apparently about one third) of conversion to electricity, and numerous other factors to decide how much of what type of Uranium to use. As you point out, there are adjustments for non-U238 fissions and the fuel must be arranged in a specific way.

Since I would probably leave out some factors, I don't believe I could calculate it with confidence. What I do know is that they load it up with a bunch of fuel, and if it stays underground and produces electricity for 30 years all is well. In the meantime, it's getting more radioactive the more it is used, and if any escapes for any reason, we are likely to have a serious problem.
jwellsy
Fuel bundles for cores that get refueled on-line have horizontal channels and small 50 lb tube bundles are shoved in one side and a spent bundle falls out the other side. This type is called an 'N' style reactor and is popular in Canada and Russia. Chernobyl was an N style reactor.

Typical BWR and PWR bundles weigh about 600 lbs. each.
All fission fragments, alpha particles and iodine gases are kept inside the fuel rods. The only mass deficit between new and spent fuel is equal to the neutrons that leaked/escaped that did not cause a fission and the gamma and xray radiations given off (which isn't very much).
ocalhoun
A little bit of googling brings this,

Quote:

The critical mass for lower-grade uranium depends strongly on the grade: with 20% U-235 it is over 400 kg; with 15% U-235, it is well over 600 kg.


Quote:

The critical mass for 85% highly enriched uranium is about 50 kilograms


The reactor needs to be close to (but not above!) critical mass in order to produce significant heat, and therefore significant power output.
Without that, you could still collect power by converting the radiation to electricity... but you would have a very low maximum power output. (Though it would last a very long time.)

Somehow, I suspect that 400kg, or even just 50kg of enriched uranium is a little bit beyond the average home-owner's budget... even if disregarding the legal issues.

Once again, I'm pretty sure the lowest practical level for a nuclear reactor to operate on would be the small-town level.
They're simply too big, too complicated, and too dangerous for the neighborhood, household, or personal level to own and operate.
jwellsy
ocalhoun wrote:


The reactor needs to be close to (but not above!) critical mass in order to produce significant heat, and therefore significant power output.


That's not how it works. A critical reactor is one that has a self sustaining neutron population, that's a good thing. A subcritical core means that power is decreasing. A super-critical core has power that is increasing. Power is measured by the neutron population density, measured at many locations and averaged. If you could never go beyond criticality, you would never get any useful energy out of it.

The technical definition of a critical reactor on a startup has three elements that all have to be true to declare it critical.
1. A positive stable Startup Rate (measure of how fast power changes)
2. Increasing power
3. No control rod motion.


Quote:

you could still collect power by converting the radiation to electricity... but you would have a very low maximum power output. (Though it would last a very long time.)


How do you do that? Are you proposing using some kind of photovoltaic cell tuned to gamma and/or neutron radiation?
ocalhoun
jwellsy wrote:

That's not how it works. A critical reactor is one that has a self sustaining neutron population, that's a good thing.

Don't you need something close to critical mass in order to achieve that self sustaining neutron population though?
Quote:

Quote:

you could still collect power by converting the radiation to electricity... but you would have a very low maximum power output. (Though it would last a very long time.)

How do you do that? Are you proposing using some kind of photovoltaic cell tuned to gamma and/or neutron radiation?

Hm... I thought that had already been done.
Perhaps I've just been reading too much SciFi though.
Bikerman
No, it uses neutron reflectors to pump 'waste' neutrons back into the pile - they replace control rods and mean that you need a comparatively small mass for the pile.
jwellsy
ocalhoun wrote:

Don't you need something close to critical mass in order to achieve that self sustaining neutron population though?


Actually you have to go a little bit supercritical because as soon as power starts increasing, other negative reactivity coefficients such as temperature and void fraction start driving power back down.

Power generation is a lot more controlled and slower than a prompt critical event.
fuzzkaizer
nice to see such a thread being discussed before fukushima -
we already know that there is a risk in using nuclear power; usually in economy risks are calculated, and then covered with some insurance fees.
so if you have to pay the insurance for the possible (long long long...term-) damage that could result from atomic energy, perhaps atomic energy would not be rentable anymore. the damage could be that vast and last for so many years that you simply would not be able to pay compensations to the victims, which still keep on arising a several generations later...
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