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Daphne Mezereum
Caldari
Posted - 2010.02.13 18:09:00 - [1]
 

Edited by: Daphne Mezereum on 13/02/2010 18:23:08
Greetings!

Seeing the rather huge confusion in the recent anti-nuke laser thread, I have decided to put my academic education and experience in/with radiophysical and radiobiological matters to good forum use.

Perhaps this little exercise will help clear up some basic misconceptions about nuclear energy/waste/etc, and I also hope that it will give me some experience in presenting my case in english.

So, without further ado, I hereby open this thread, where you are free to ask me questions about (almost) all matters radiological and nuclear, and I will try and explain them to you.


(Herbert West is not my real name, but the name I use on almost all internet and social places/gatherings, but alas, all permutations of it were taken. Should I ever forget to post with this character, do know, that M'ktakh is my alt)

Edit: no joke/idiocy questions please.

Caldari Citizen20090217
Posted - 2010.02.13 18:19:00 - [2]
 

If I get exposed to radiation will I really develop superpowers like in the movies?


Grimpak
Gallente
Midnight Elites
Echelon Rising
Posted - 2010.02.13 18:29:00 - [3]
 

Originally by: Caldari Citizen20090217
If I get exposed to radiation will I really develop superpowers like in the movies?


Razz


there is a question that I have wondered for some time tho:


considering how "widespred" nuclear waste is these days, and the relative ease of how a country can build a dirt-bomb, what is the damage that such bomb can make in.. let's say, a moderately populated area?

Lance Fighter
Amarr
Posted - 2010.02.13 18:34:00 - [4]
 

If i am exposed to radiation and grow a third arm from my stomach, what would be the best course of action?

Shoot myself in the brain

anti-radiation meds

Pray that the gods will save me

Cut it off with a laser


Zions Child
Caldari
The Resident Haunting
Posted - 2010.02.13 18:43:00 - [5]
 

Originally by: Lance Fighter
If i am exposed to radiation and grow a third arm from my stomach, what would be the best course of action?

Shoot myself in the brain

anti-radiation meds

Pray that the gods will save me

Cut it off with a laser




That sounds remarkably similar to a question on the G.O.A.T in Fallout 3....

Sazkyen
Posted - 2010.02.13 18:44:00 - [6]
 

Edited by: Sazkyen on 13/02/2010 18:44:57

If I released two parallel LASER beams into space would they:

- remain parallel
- close the distance
- get farther and farther from each other



Lance Fighter
Amarr
Posted - 2010.02.13 19:05:00 - [7]
 

Originally by: Zions Child
Originally by: Lance Fighter
If i am exposed to radiation and grow a third arm from my stomach, what would be the best course of action?

Shoot myself in the brain

anti-radiation meds

Pray that the gods will save me

Cut it off with a laser




That sounds remarkably similar to a question on the G.O.A.T in Fallout 3....

Oh really Laughing

M'ktakh
Posted - 2010.02.13 19:33:00 - [8]
 

Edited by: M''ktakh on 22/03/2010 22:21:33
Grimpak: lets take a not really realistic, but worst case scenario. We spread a truckload of radwaste over a city. Lets, for the sake of simplicity, assume that we have released 1PBq of activity. This would have to mean that we released short-lived, highly active products such as Iodine isotopes, a realistic number would be 1GBq. For comparison, the total release of Chernobyl was 4 EBq, or 4000 PBq. Yes, I will be using SI prefixes. Suck it, non-metrics. Also, the total yearly release of all coal plants is about 0,5EBq, while the total release of all nuclear power plants is not even in the 10 PBq range. Yes, coal plants puff more radioactive material into the air than NPPs.

Next, we assume that all persons get contaminated, that all activity gets ingested, and that all activity gets ingested with the worst dose conversion factor (how much actual dose you get from the intake of a certain activity). Lets fix this DCF at 10^-6 (orders of magnitude higher than most isotopes).

Thus, with the worst case scenario, we arrive at 1PBq*10^-6=1GSv. It takes about 10Sv to kill a man, and again, we assume that this is an acute exposure, with all the worst pathways. Thus, we would arrive at 100 million people killed.

However, certain things are to be considered:
- the released radwaste is not all iodine (in fact, the dangerous iodine isotopes have a halflife of weeks at most)
- the activity released is grossly over measured, it should be 1GBq
- the activity will not disperse evenly
- not all activity will be ingested/inhaled
- the DCFs are much lower
- countermeasures will be taken

Considering these effects, all of which are at least an order of a magnitude, we get maybe 10 thousand people dead.

However: it is safe to say that whoever was close to the detonation of the dirty bomb is dead (lets say a 100 m radius in even terrain), but the amount of fallout drops at least with radius squared. Thus, it is safe to assume that almost all activity will be released in a tight spot.

Dirty bombs are great terrorist weapons, you get a mild causality effect and generate lots and lots of fear, confusion, and panic (the city is going to be evacuated, after all). In a military sense, they are useless.


I will add however, that getting sufficient amounts of "right" radwaste is very, very hard. The IAEA is very, very keen on sniffing out nanomols of rad material.

Sazkyen: I cant answer this without knowing what gravitational forces are in their way. In an absolute "empty" scenario, they should remain paralell, if the Earth does not have any gravitational pull.


Edit: damn, alt post.

Grimpak
Gallente
Midnight Elites
Echelon Rising
Posted - 2010.02.13 21:47:00 - [9]
 

Edited by: Grimpak on 13/02/2010 21:48:07
Originally by: M'ktakh
Dirty bombs are great terrorist weapons, you get a mild causality effect and generate lots and lots of fear, confusion, and panic (the city is going to be evacuated, after all). In a military sense, they are useless.

I will add however, that getting sufficient amounts of "right" radwaste is very, very hard. The IAEA is very, very keen on sniffing out nanomols of rad material.


yes, but don't forget that there are certain nuclear-capable countries that can provide the black market with this radwaste, thus making it even more easy to produce then your run-of-the-mill A-bomb.


range is limited, yes, but with the right ammount of explosives, it can do quite the damage. but yes, it's a more of a "terror" weapon then an actual WMD.

Alchemist Zemont
Gallente
Hysteria Nexus
Posted - 2010.02.13 21:54:00 - [10]
 

Does one kiss make me a lesbian?

Sazkyen
Posted - 2010.02.14 01:03:00 - [11]
 

Edited by: Sazkyen on 14/02/2010 01:03:46
Originally by: M'ktakh
Edited by: M''ktakh on 13/02/2010 19:47:40
Edited by: M''ktakh on 13/02/2010 19:44:36

Sazkyen: I cant answer this without knowing what gravitational forces are in their way. In an absolute "empty" scenario, they should remain paralell, if the Earth does not have any gravitational pull.


Edit: damn, alt post.


Am I to understand that space is Euclidean?

M'ktakh
Posted - 2010.02.14 02:07:00 - [12]
 

Edited by: M''ktakh on 14/02/2010 02:08:36
Originally by: Sazkyen
Edited by: Sazkyen on 14/02/2010 01:03:46
Originally by: M'ktakh
Edited by: M''ktakh on 13/02/2010 19:47:40
Edited by: M''ktakh on 13/02/2010 19:44:36

Sazkyen: I cant answer this without knowing what gravitational forces are in their way. In an absolute "empty" scenario, they should remain paralell, if the Earth does not have any gravitational pull.


Edit: damn, alt post.


Am I to understand that space is Euclidean?



The real universe is by no means euclidean. Your question, however, did not specify the parameters of the above experiment. Thus, I had to simplify and make the universe a uniformly empty, thus, euclidean space.

(And your question relates to QM and relativity, not nuclear physics:P)


Grimpak: yeah, it might be "easy" to produce, but in a military sense, it is merely and inconvenience. I, for one, consider this whole "dirty bomb" thing a bit overhyped.

Chaos Incarnate
Faceless Logistics
Posted - 2010.02.14 02:28:00 - [13]
 

i remember doing research on a project on a missile called the sprint, which was one of those fun old-timey antiballistic missiles. Anyhow, the sprint used a small nuclear warhead that as ye old wikipedia states, destroyed an inbound missile by neutron flux

however, I could never find anything that said how at all neutron flux would damage or destroy a missile; i figured the neutrons might damage or destroy the nuclear material in the bomb itself but...i've no idea. So, how's it work?

Daphne Mezereum
Caldari
Posted - 2010.02.15 22:09:00 - [14]
 

Originally by: Chaos Incarnate
i remember doing research on a project on a missile called the sprint, which was one of those fun old-timey antiballistic missiles. Anyhow, the sprint used a small nuclear warhead that as ye old wikipedia states, destroyed an inbound missile by neutron flux

however, I could never find anything that said how at all neutron flux would damage or destroy a missile; i figured the neutrons might damage or destroy the nuclear material in the bomb itself but...i've no idea. So, how's it work?


Hmm.

Well, for the structural material, a high neutron flux means a lot of atom dislocations, thus, the crystalline strucutre becomes weaker, causing the material to become brittle and breakabel (this is the first and foremost limiting factor for the lifetime of any nuclear power plant).

This, is, however, not a that quick a process. It may cause the casing of the warhead to become brittle and the warherad to fragment, but the more likely explanation would be:

Warheads are not critical, they do not have a critical mass/geometry/density. But they contain fissionable material. Add a high neutron flux to this material, and the chain reaction will start, causing the bomb to go off in some extent.

So, the anti-missile warhead irradiates the intercepted warhead with a high neutron flux. Some of these neutrons are captured by the fissionable material, and the material starts a chain reaction. This chain reaction is non-sustainable (the chain reaction in a bomb is sustainable as long as the bomb stays critical). As energy is released in this reaction, this energy will trow the bomb apart, thus destroying it, while keeping most of its fissionable material intact. Fissionable material is less a radiobio hazard than fission products are.

Apart from these two mechanism, i cant really think of anything else, most warheads have dead reckoning homing systems, so frying the electorincs does not make much sense.

Iasius
Short Bus Pole Dancers
Posted - 2010.02.15 22:28:00 - [15]
 

Q: Is it true that precision medical instruments have to be manufactured using steel from WW2 ship wrecks as they have not suffered from nuclear bomb testing irradiation that has affected the planets atmousphere.

Daphne Mezereum
Caldari
Posted - 2010.02.15 22:39:00 - [16]
 

Edited by: Daphne Mezereum on 15/02/2010 22:58:06
Edited by: Daphne Mezereum on 15/02/2010 22:42:09
Originally by: Iasius
Q: Is it true that precision medical instruments have to be manufactured using steel from WW2 ship wrecks as they have not suffered from nuclear bomb testing irradiation that has affected the planets atmousphere.


True. I'm not sure about medical instruments, but all the casings of our high definition detectors are made out of pre-WWII metals. This is done so that the high-gamma active fallout materials like Cs-134 do not interfere with the detected results.

The high puirty Germanium detectors I had to use in some of my demo experiments had measurement chambers made from the sttel of those bridges that got bombed into the Danube during the siege of Budapest (where my uni and I are located)


Keep the questions coming, guys:)

Daphne Mezereum
Caldari
Posted - 2010.02.17 18:48:00 - [17]
 

Shameless self-bump

Cersei Xoy
Posted - 2010.02.17 19:31:00 - [18]
 

How powerful is the heaviest known nuclear warhead if compared to the bomb on Hiroshima and what technological breakthroughs have contributed in the making?

Malcanis
Caldari
Vanishing Point.
The Initiative.
Posted - 2010.02.17 20:45:00 - [19]
 

Originally by: Cersei Xoy
How powerful is the heaviest known nuclear warhead if compared to the bomb on Hiroshima and what technological breakthroughs have contributed in the making?


Tsar Bomba.

M'ktakh
Posted - 2010.02.17 21:08:00 - [20]
 

Originally by: Malcanis
Originally by: Cersei Xoy
How powerful is the heaviest known nuclear warhead if compared to the bomb on Hiroshima and what technological breakthroughs have contributed in the making?


Tsar Bomba.


Tsar Bomb was about 50 megatons (TNT-equivalent), Little Boy had ~15 kilotons, Fat Man 21 kilotons.

The WWII bomb were one-stage fission only bombs, while Tsar Bomb was a multi-threestaged hydrogen bomb.

Lance Fighter
Amarr
Posted - 2010.02.17 21:08:00 - [21]
 

What are your thoughts on nuclear powered cars and/or houses?

Daphne Mezereum
Caldari
Posted - 2010.02.17 21:24:00 - [22]
 

Edited by: Daphne Mezereum on 17/02/2010 21:24:45
Originally by: Lance Fighter
What are your thoughts on nuclear powered cars and/or houses?


Cars are simply not feasible with current technology, or even technology in development. The US had some experiments with nuclear powered aircraft, and the same basic type (molten salt) of reactors are one of the six designs for the upcoming (2030 and onwards) generation IV. reactors. However, even if technologically feasible, car-powering reactors are simply not economical. The greatest cost of a nuclear power plant is its construction, taking up up to 80% of total lifetime costs, with fuel and personnel and eventual disassembly taking only 20.

So, for a nuclear powered car to even begin to be competitive with other cars, it would have to work for 50-60 years. That's not going to happen.

As for nuclear powered houses, the japanese (it think the Hitachi&Co brand of the nuclear industry) have a design for a small, 100-200MW nuclear reactor that is rumoured to require only very minimal maintenance, and is aimed at supplying large consumers, like factories or universities with power.

There are designs for nuclear reactors, and even nuclear power plants that have a near-zero maintenance need and have huge passive safety systems to guarantee almost nothing can go wrong. The tech is there, or almost in reach. But for this to work economically, the current systems of energy transportation would need to be redesigned. I can, however, see the japanese building a demo building/small city with such a reactor.

My personal opinion on this matter is that due to the fact that costs scale below linear with the size, It is more prudent to build a few big reactors, with one power plant having more than one reactor (the largest I think has eight reactors), and this kinda rules out the point of "here you go, a small power plant for your village".

Its not impossible, but its improbable.

Nuclear cars, that's a big no.

Lance Fighter
Amarr
Posted - 2010.02.17 21:30:00 - [23]
 

Edited by: Lance Fighter on 17/02/2010 21:31:16
If costs do indeed scale linearly with size, would the cost of building multiple small reactors not cost the same as a single large reactor that produces the same output? (+redundancy)
edit wait what? below linearly?

Also, I was under the impression that current nuclear reactor technology still largely revolves around boiling water.. hence the usual boiler towers you associate with a nuclear power plant, yes?

Daphne Mezereum
Caldari
Posted - 2010.02.17 21:52:00 - [24]
 

Edited by: Daphne Mezereum on 17/02/2010 21:54:01
Originally by: Lance Fighter
Edited by: Lance Fighter on 17/02/2010 21:31:16
A, If costs do indeed scale linearly with size, would the cost of building multiple small reactors not cost the same as a single large reactor that produces the same output? (+redundancy)
edit wait what? below linearly?

Also, I was under the impression that current nuclear reactor technology still largely revolves around boiling water.. hence the usual boiler towers you associate with a nuclear power plant, yes?



A, Sorry, I need some sleep to make a comprehensible sentence. Below linearly = for a size increase of X you only get less than X increase in costs, as stuff like the building ground can be shared, there are parts of the staff that can be shared, etc,etc. If you have two reactors, then they can share a lot of their attached buildings and systems.

Nuclear reactors are only the containers in which the chain reaction happens. For this to become a power plant, you need all sorts of stuff, like things explained below:

B, Those are cooling towers for the tertiary circuits of the reactors.

Thats how it happens: the primary coolant of the reactor goes into the reactor, into the place where the chain reaction produces a lot of heat, and absorbs this heat. The primary reason we have been using water as the primary coolant for decades, and will use for decades, is that water has a very high heat capacity, it can absorbs a ****load of heat compared to other stuff. This, however, also limits the reactors heat, and thus output, as we can not heat water over ~350, or it will not stay fluid, no matter the pressure.

That is why gen IV, designs usually have other primary coolants, like molten salts, or metals like lead or sodium, because they can be heated up to 600-700 degrees.

Okay, so we have a primary coolant. This then goes to a so-called heat exchanger, where it meets the secondary circuit through a series of pipes. This secondary circuit is always water, as we use the heat of the primary coolant (usually around 320C temperature) to boil this water. The resulting steam is then blown onto the turbines, and voila, electric power. Due to thermodynamic reasons, the whole process has an efficiency of around 30%. GenIV designs can have an efficiency of around 40%, but to go higher, we would need some different material to make steam out of, and that just aint there. (Yet?)

So anyway, the secondary circle then passes the generator, and now, it needs to become water again, not steam. To do this, one has to cool it down. This is done with the tertiary circle, which is room-temperature water either extracted from a local lake/river, or, in your case, kept in those huge towers. After the tertiary circle has cooled down the secondary one, it becomes a little warmer, and that's why they then pump it up into those hollow towers so it can cool off.

The primary and secondary circles are always closed ones, (the primary is radioactive and stinking hot and high-pressured, the secondary is "just" hot and high-pressured), the tertiary circle is usually an open one if they have a nearby water source, or a closed one when they have none.


Very, very important edit: ALL power-plant based electricity generation (nuclear, coal, gas, oil, wood, biomass, etc) revolves around heating water up and using steam to drive generators. If ever a Greenpeace/etc ******* says to you that "oh, power plants only boil water, thats so dumb", you are free to punch them in any part of their body till they get a clue.

Lance Fighter
Amarr
Posted - 2010.02.17 22:08:00 - [25]
 

So can such a system be downsized to the point where it would be even practical for a house or car to use? It sounds to me like the whole 3 part system would require a good deal of space (not to mention the whole steam turbine issue)..

Is it even possible to produce energy through nuclear means and bypass the turbines?

Daphne Mezereum
Caldari
Posted - 2010.02.17 22:14:00 - [26]
 

Originally by: Lance Fighter
A: So can such a system be downsized to the point where it would be even practical for a house or car to use? It sounds to me like the whole 3 part system would require a good deal of space (not to mention the whole steam turbine issue)..

Is it even possible to produce energy through nuclear means and bypass the turbines?


A. Well, the japs have some crazy designs, but as I see it, its not practical, not for a house. Maybe for a whole district, but not a house.

B: No. You need something that conducts and converts the energy released in a nuclear fission.

Fission-->heat-->steam-->electricity. You can cut out the secondary circle, thats called boiling water reactors (I'm linking wiki because they have a very informative gif over there), but those reactors are not as safe as three-circuited pressurized water reactors. So no, converting the energy released in fission directly into energy is not possible, sadly. Would be nice, but no.

Magnus Nordir
Caldari
Nordir Industries
Posted - 2010.02.18 02:47:00 - [27]
 

Edited by: Magnus Nordir on 18/02/2010 02:49:55
Originally by: Lance Fighter
Is it even possible to produce energy through nuclear means and bypass the turbines?


It's called a Radioisotope thermoelectric generator

If it weren't for the paranoid eco-hippies, we could easily have free energy with one of these in every basement and every car.

Edit: It's not "through nuclear means", but it bypasses traditional steam turbines, kind of.

Odium Devotus
Posted - 2010.02.18 03:12:00 - [28]
 

LFTR-
is it as badass as it sounds?
Whats the deal with u-233?

Also,
Ive heard mentioned many times, recycling/scrubbing/cleaning/waste management of or whatever you want to call it regarding nuclear waste. (France for instance), but i havent heard any specifics. What kind of technology's and processes are involved in this sort of thing.

and finally -
cant everything be solved by throwing a bunch of money at it?


I for one look forward to the day when energy is seen as a tool to be exploited again, and no longer a dirty word.

Bellum Eternus
Gallente
The Scope
Posted - 2010.02.18 04:09:00 - [29]
 

Question:

Is it possible/realistic to design a single stage to ignition fusion weapon with an optical laser for an ignition source using current levels of technology?

Lance Fighter
Amarr
Posted - 2010.02.18 05:17:00 - [30]
 

Edited by: Lance Fighter on 18/02/2010 05:23:33
Originally by: Magnus Nordir
Edited by: Magnus Nordir on 18/02/2010 02:49:55
Originally by: Lance Fighter
Is it even possible to produce energy through nuclear means and bypass the turbines?


It's called a Radioisotope thermoelectric generator

If it weren't for the paranoid eco-hippies, we could easily have free energy with one of these in every basement and every car.

Edit: It's not "through nuclear means", but it bypasses traditional steam turbines, kind of.

yes, the seebeck effect. Why isnt that used more?
The wikipedia page claims its more of a battery than a real power source, so I assume its non-renewable
Also, I assume it requires a source of cooling; In space, you can merely radiate excess heat... straight into space, but im guessing its not so on Earth
edit
it would appear that its been used in lighthouses and such.. apparnetly the only problem is that the radioactive material is.. well, radioactive and not contained to the level of 'omg its a nuke let nobody near it'


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