@8644371 My understanding is that the steam in the primary coolant loop is dangerous (as in dangerously radioactive) but the steam in the secondary coolant loop is not. The steam in the secondary coolant loop may be dangerously hot, but should not be radioactive.
If the control rods automatically lower during an emergency shutdown, is that enough to avert a meltdown? It seems during the current nuclear crisis in Japan that a lack of coolant circulation caused at least a partial meltdown due to the core being exposed to air. So i would assume the heat intensified after this exposure to the point that the remaining water turned to steam and the immense pressure caused an explosion.
@altjff15 That's a good question, and I am not sure of the answer, but my guess is that it would depend on the design of the reactor. From what they are saying in Japan right now, there is apparently still enough heat being generated, even in shutdown mode, to cause some problems over time. At the moment I'm writing this, the focus is not actually on the core, but on the pools of spent fuel, which are more exposed right now.
@derekowens thanks, now another thing I've been really curious about is why there would be so many problems with multiple reactors at the same time if they are, I assume, independent of each other. If they are in fact independent functioning units, then there must be some flaw in the model type design because the likelihood of so many crucial failures happening coincidentally is not a reasonable expectation. Are the cooling and other systems interconnected? Do you have any insight on this?
It's my understanding that in most reactors, the control rods aren't enough to fully control the reaction. A 'cold shutdown' is maintained with the control rods & the constant supply of liquid coolant. This rule really only holds true for the active fuel, hence the reason spent fuel only needs water, not control rods. Granted, Im only a layman, so I could be wrong.
@pepzit The description I gave here is a big picture overview, and as far as I know, the ideas in this video would apply to both a BWR and PWR, the main difference being that in a PWR, the pressure is too high for the water to boil. The basic idea, though, of using nuclear fuel to heat the water to make steam to turn a turbine, is the same in both.
at first (correct me if i am wrong... we are doing this in science) the chernobl disaster exsploded first and o nly melted down when they tried to put it out with fire. at three mile island they had a melt down but the affects were not as drastic as the ones ant chernobl!!!
@mini1066 That may be correct about Chernobyl - it's been a while and I would have to look up the details. At Three Mile Island, I believe they had a partial meltdown. The core started melting, but some automatic safety controls kicked in and, I think, supplied some extra coolant, so the core did not completely melt down. Authorities claim that no significant radiation was released. Some people in the area who later got cancer did say they thought the accident was responsible.
I thought that the steam that turns the turbines also holds a bit of radioactivity. If so, when it cools off at the cooling towers, dosn't the steam emmited from the towers hold that radioactivity also?
@MrWant2Know My understanding of it is that the secondary coolant is either not radioactive, or else is not radioactive to any significant degree. I'm not a nuclear engineer though, and may need correcting on that point.
From what I understand, the secondary coolant does not become radioactive, and the cooling towers are safe, at least when considering radioactivity. The dangerous stuff is the primary coolant, and especially the core.
@derekowens Chernobyl was a graphite reactor operating under experimental rules which is why it wasn't in a containment building. The core did melt but it never left the basement, meltdowns never leave the building so no they don't melt into the earths crust. Had the reactor been in a container the steam never would of escaped either. Don't forget that the primary doubles as the moderator which is crucial to nuclear fission.
The steam isn't dangerous? How so?
The steam became steam when it passed right by the nuclear core. It doesn't become radioactive then?
8644371 2 months ago in playlist Physics - Electric Circuits
@8644371 My understanding is that the steam in the primary coolant loop is dangerous (as in dangerously radioactive) but the steam in the secondary coolant loop is not. The steam in the secondary coolant loop may be dangerously hot, but should not be radioactive.
derekowens 2 months ago
nice video thanks for sharing very interesting .. god bless
magdakorpi 3 months ago
@robreeve Rob, I do hope to re-record this video soon. If you have some specific issues or corrections to offer now would be a good time.
derekowens 9 months ago
If the control rods automatically lower during an emergency shutdown, is that enough to avert a meltdown? It seems during the current nuclear crisis in Japan that a lack of coolant circulation caused at least a partial meltdown due to the core being exposed to air. So i would assume the heat intensified after this exposure to the point that the remaining water turned to steam and the immense pressure caused an explosion.
altjff15 11 months ago
@altjff15 That's a good question, and I am not sure of the answer, but my guess is that it would depend on the design of the reactor. From what they are saying in Japan right now, there is apparently still enough heat being generated, even in shutdown mode, to cause some problems over time. At the moment I'm writing this, the focus is not actually on the core, but on the pools of spent fuel, which are more exposed right now.
derekowens 11 months ago
@derekowens thanks, now another thing I've been really curious about is why there would be so many problems with multiple reactors at the same time if they are, I assume, independent of each other. If they are in fact independent functioning units, then there must be some flaw in the model type design because the likelihood of so many crucial failures happening coincidentally is not a reasonable expectation. Are the cooling and other systems interconnected? Do you have any insight on this?
altjff15 11 months ago
@altjff15
@derekowens
It's my understanding that in most reactors, the control rods aren't enough to fully control the reaction. A 'cold shutdown' is maintained with the control rods & the constant supply of liquid coolant. This rule really only holds true for the active fuel, hence the reason spent fuel only needs water, not control rods. Granted, Im only a layman, so I could be wrong.
sakar181 11 months ago
Very good presentation! This is a BWR (boiling water reactor), like the Fukushima power plant, and not a PWR (pressurized water reactor) right?
pepzit 11 months ago
@pepzit The description I gave here is a big picture overview, and as far as I know, the ideas in this video would apply to both a BWR and PWR, the main difference being that in a PWR, the pressure is too high for the water to boil. The basic idea, though, of using nuclear fuel to heat the water to make steam to turn a turbine, is the same in both.
derekowens 11 months ago
Very clear and interesting explanation... thank you!
MarketingSecurity 11 months ago
at first (correct me if i am wrong... we are doing this in science) the chernobl disaster exsploded first and o nly melted down when they tried to put it out with fire. at three mile island they had a melt down but the affects were not as drastic as the ones ant chernobl!!!
mini1066 1 year ago
@mini1066 That may be correct about Chernobyl - it's been a while and I would have to look up the details. At Three Mile Island, I believe they had a partial meltdown. The core started melting, but some automatic safety controls kicked in and, I think, supplied some extra coolant, so the core did not completely melt down. Authorities claim that no significant radiation was released. Some people in the area who later got cancer did say they thought the accident was responsible.
derekowens 1 year ago
superb explanation / video
azhanr 1 year ago
I thought that the steam that turns the turbines also holds a bit of radioactivity. If so, when it cools off at the cooling towers, dosn't the steam emmited from the towers hold that radioactivity also?
MrWant2Know 1 year ago
@MrWant2Know My understanding of it is that the secondary coolant is either not radioactive, or else is not radioactive to any significant degree. I'm not a nuclear engineer though, and may need correcting on that point.
derekowens 1 year ago
nukular fuck yeah
mortym 1 year ago
your videos are bloody awesome mate,
cheers.
rockmountfatcat 2 years ago
hahaha, loved the beg. great vid
xrayeyesb4u 2 years ago
Hey exellent video! Very good!
Tell me, what did you use to draw these paintings?
federalfsx 2 years ago
do the secondary coolant become radio active when it goes in the primary coolant and if it does, do the cooling towers get radio active?
bullittkid 2 years ago
From what I understand, the secondary coolant does not become radioactive, and the cooling towers are safe, at least when considering radioactivity. The dangerous stuff is the primary coolant, and especially the core.
derekowens 2 years ago
@derekowens Chernobyl was a graphite reactor operating under experimental rules which is why it wasn't in a containment building. The core did melt but it never left the basement, meltdowns never leave the building so no they don't melt into the earths crust. Had the reactor been in a container the steam never would of escaped either. Don't forget that the primary doubles as the moderator which is crucial to nuclear fission.
But other than that nice work.
Powdermonkey09 1 year ago
@Powdermonkey09 Thanks, man! I'll try to correct that and post a new video when I get some free time.
derekowens 1 year ago
i found ur videos very useful 4 revising 4 exams.
Thankz
EXCELENT VIDEOS
Eljreiby 2 years ago
Good explaining video with many details. Nice !
PhoeNiX9778 2 years ago