Understanding Nuclear Power Plants: Total Station Blackout 

but what if the emergency fire trucks that supply water to the calandria fail too?

@@Sharpless2 it explode,simple

It doesn’t matter, a major accident is always a possibility, no mater what, and how much is in place.

Yes. Yes we are. CANDU reactors are fucking awesome and we have every right to be proud of them... ...especially when Japan is still running reactors that they _specifically chose over CANDU reactor designs because they were American,_ when those designs even at the time were known by GE to be pretty awful and wouldn't build them themselves in the US.

@@liesdamnlies3372 You saw what happened at Fukushima! Loss of power=loss of coolant flow, and there are no passive systems. Big problem.

2:18 ExTrEmLy UnLiKlY!!!!

@@liesdamnlies3372 American is best build ;)

@@kushpaladin *oldest FTFY ;)

i love how you just replyed that to every comment in this video

yep

But the accident would totally keep going because they forgot how to pump water in.

But won't the heat keep evapourating the water you pump in and produce radiated steam? How to get rid of it?

LMAOOO

Now I've got this image too lmao

YOU ARE IDIOT

Nice. hehehe

That’s not going to correctly it

Yeah pretty much lmao

yes yes

They did that at Fukushima and it caused the cores to melt further

But never forget that supplying water with emergency equipment such as fire trucks stops the accident. It's very important to remember that supplying water with emergency equipment such as fire trucks stops the accident. But in case the accident is not stopped, you can always supply water with emergency equipment, such as fire trucks. That stops the accident.

Mgtow-M3 Modern Masculine Men How? Those isotopes are contained within the fuel rods unless the cladding has a hole, which is rare.

that's because the fukushima reactor had a different set of things that had happened uncontrollably before they started spraying water on it, the point of this reactor is that the states of a meltdown are very controlled and relatively easy to remedy. In the fukushima meltdown, there was a large hydrogen explosion before emergency personnel were able to intervene. That's the main 'final blow' to a lot of these meltdowns. If there is no hydrogen explosion, the situation is under much more control because the vessels can do what they're designed to do, because all they have to do is soak up heat. But once you apply an explosion from large amounts of hydrogen that's already under high pressure BEFORE the explosion, then things go to hell. That's the reason their system that supposedly converts hydrogen to water is there, to prevent a hydrogen explosion, if there is no explosion then their safeguards can continue to operate as intended, and water can be added to supplement that, as all their safeguards are just trying to reduce pressure of hydrogen, and add coolant.

*Cries in Soviet*

The positive void coefficient aspect of the CANDU reactors are almost the same as RBMK-s from Chernobyl. Funny to say polar opposite with the same and not so safe characteristic. Also the online refueling with robots and natural uranium as fuel also similar to the RBMK-s. CANDU is the well made RBMK. Not the polar opposite.

@@namelesske For the sake of semantics - RBMKs used slightly enriched Uranium Dioxide fuel (~2% U235) wheras CANDUs use completely unenriched Uranium Dioxide (~0.7% U235) which is why heavy water (D2O) is required for both the moderator and coolant. Any reactor that uses light or heavy water (BWR, PWR, CANDUs, etc) are subject to positive void coefficients - it is unavoidable as the main heat transport system cannot reasonably be pressurized to the point where voids don't form at the temperature which they operate at (for context, CANDUs MHTS is pressurized to ~11MPa, on average across the system). (One of) the issue(s) with the RBMK was the insanely large reactor core which made transients (areas of increased fission due to high neutron density in a region, and one of the causes of voids forming in the core) common and difficult to deal with. CANDU reactors mitigate this by inserting adjuster rods (not the same as control rods) as well as tanks of light water where the water level varies based on the neturon flux of that area - these act as neutron absorbers and are littered throughout the reactor core. This, in turn, reduces neutron flux in a region and mitigates the formation of voids. And for additional context, at 80%-100% full operational power there will be a void of 2% (2% of the volume being steam, 98% being D2O) that forms on the outlet side of the heat transport system. This is closely monitored and controlled. Of course it is plausible to draw connections between CANDU and RBMK reactors, they are, at their core, similar instruments. But there are truthfully very few major similarities between the two reactor types. A few examples of which are (CANDU vs RBMK): Heavy water vs Graphite moderator, vertical fuel rods vs horizontal, massive containment structure around the reactor vs virtually no containment structure. All these things aside the main difference lies in the incredible amount of safety systems in place within CANDUs.

​@@Jvdg3m3nt BWRs and PWRs have a negative void coefficient because the moderator acts as the coolant, so when a void forms in the moderator, locally the fuel is under-moderated and the chain reaction slows down. Positive void coefficients happen when the moderator is different from the coolant and the coolant acts like a neutron absorber, like light water in both CANDU and RBMK; when the void forms, locally there's a reduction in neutron absorption but not in neutron moderation, so the chain reaction increases.

@@Z80Fan A fair point, although inherently it would become slightly under-moderated as well since the coolant does act to slightly moderate neutrons (both the coolant and moderator in CANDUs are heavy water). Should be noted that the 2% void coeff is built into the design of CANDU reactors in order to maximize heat transfer to the secondary side. My main point was the degree of independent and redundant safety systems built into CANDUs draws no comparison to the RMBKs

@@Jvdg3m3nt I was under the impression that CANDU used light water for coolant. My bad.

IF ONLY IDIOTS DID NOT RULE

meanwhile : anti nuclear activists : 👉😑👈

They have all the designs online too. It's pretty crazy to think they're okay for everyone knowing what they are doing because of how safe it really is.

Civilian reactors have public documentation, you just need to know where to find the safety report

WHAT CANDU IS CANDU

I only ended up finding them now, but I'm indeed binge watching them. No doubt it'll be on Netflix soon enough.

I just can hear Jager (from rainbow 6 siege) saying "You Can Stop Worrying About nuclear accidents now"

That's the problem with life, Hindsight is a wonderful educator, but no use at the time you need the ideas. The shuttle was a fine example.... after Columbia every shuttle got a once over by the ISS to check for damage, didn't help the Columbia crew though.

Mix a bunch of heavy water with uranium nitrate in a steel container 1-2m in diameter.

@@leerman22 Interesting reply.

+Shawn Thompson Just to add to what cnscccsn already said: At Chernobyl, the melted fuel (the "elephant's foot", I encourage you to check it out) only pierced a few cm into the concrete in the building foundation, so we have no reason to believe it would melt into the earth very far, even if it were dumped on bare soil at peak operating temperature (although I wouldn't recommend trying it!). But if it somehow did melt arbitrarily far into the Earth, once it hits ground water it would shoot a slurry of radioactive mud high into the air like a geyser in a (theoretical) phenomenon known as the China Syndrome. Thanks for your interest in Nuclear Power!

Shawn Thompson Supplying water to the calandria would prevent an accident

im surprised you wouldnt have a ginormous battery bank to power the water pumps just incase the worst was to happen and all the generators quit it might buy you another few days before losing the core or perhaps cover the roof with solar panels and use the power from those to cool the reactor during the day and to recharge said battery bank fi you are going to spend $200 million on a nuclear reactor you might as well drop another $2 million on solar panels and batteries to protect your investment if all other power sources fail

CANDU should have wolfranium floor/calandria. Tungsten is the only corium-resistant material on Earth! It's melting point is around 3500 degree when corium reach max 3100. Wolfranium as heavy metal have excellent heat conduction! If Fukushima have tungsten shield, it corium wouldn't melt through the vessel.

the battery banks only power instruments did YOU watch the video?

They had some pretty bad accidents on the prototypes for this reactor in the 50s

@@samalbury9183 I think that is the case, but we were also some of the earliest adopters of nuclear reactors.

The Marshmellow supplying water to the calandria would prevent the accident

We (Canada) really, _really_ took the lessons learned at NRX to heart and got super-serious, even almost paranoid, about reactor safety. NRX was a small research reactor in the 50s which had an accident; the entire thing started with human error and was worsened by human error, and that lesson (and others) became central to our reactor designs. Automatic safety systems that do not rely on any human input were simply a given after that (and was/is why an incident like Chernobyl simply cannot happen, amongst other reasons).

Here's some experts going into gritty details if your curious. I find nuclear plant safety fascinating. ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-cf9G8vddUjk.html ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-ryI4TTaA7qM.html

Okay I did, thank you.

YetiOnCocaine you can supply water to the calandria to prevent the accident

The problem is the lack of said fluid

@@user-vv7qp5nm4f the Great lakes have a tiny amount of water that you might be able to pump from

Hello Evan, Multiple means of adding water to the reactor have been added or are in the process of being added. These are designed to prevent significant core damage. The added means also includes the use standard fire truck connections.

@@cnscccsn Also, the low pressure of the moderator, like helps with water addition in the case of CANDU reactors. I believe that relieving the high pressure in the core at Fukushima to allow water addition helped cause the hydrogen explosion?

Yes. Anything associated with safety is connected to the power distribution buses that can be powered from standby generators, emergency power generators, and portable diesel generators. There are several gravity supply systems that supply water to the boilers, including the emergency storage water tank, the steam generator emergency cooling system and the deaerator feedwater tank. There's also external headers that can use firetrucks and portable pumps to drive water into the feedwater systems to keep the boilers full.

The spent fuel is quite content to sit unattended for weeks. If the water levels in the spent fuel pool drops (somehow) it can be replenished any number of ways throughout an accident response.

If It was large enough to deal significant damage, you would be worring about the environment you are in.

The special devices just catalyze the hydrogen into something else that is rather less prone to violent explosions...I forget what. Brain is foggy today.

Actually, now it's 4. Gentilly-2 has been shut down since the video was published in 2013.

I believe coal plants actually release more radioactive material per day than properly functioning nuclear reactors do.

compwiz00 To elaborate on this, I've heard that this is because of small amounts of uranium in coal.

Trevor Lawrence supplying water to the calandria would prevent the accident

Just supply water to the coal, that will stop the accident...

Trevor Lawrence Such a small amount that even if you stood right in that spot for 10 years you'd still get far less radiation exposure than you do from a single international airline flight.

CANDU technology was sold off to SNC; it has not been widely licensed, nor is it likely to be due to cost of build.

Thank you for your answer.

You can supply water to the calandria to prevent accidents.

dddaammmnnn, you guys are really ready for anything! Thx for keeping us safe. Oh and if everything else fail, I will get my garden hose to supply water to the calandria to prevent accident....but seriously, at that point I think we have definitely bigger problems.

ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-RZjhxuhTmGk.html Planes have always been an obvious hazard, and were planned for in the earliest days of nuclear power. The newest reactors deigned after 9/11 "EPR" and "AP1000" have double wall containment structures with a gap between them, just to be extra paranoid. A plane would splatter like a bug, and missiles would need to hit the exact same spot at least twice. Even then the safeties would have a good chance of recovering.

As far as I'm aware, never. They have been tested, and tested, and had redundancies piled on them. e.g. the automatic shut-off systems are controlled by independent monitoring systems running on voting logic (three systems, where two must agree on the action to be taken; similar systems are used in other safety-critical applications like aircraft or train control systems). There have been two accidents in Canada. The first was at a research reactor, NRX, in the 50s. All the lessons from that were taken quite seriously and incorporated into all future designs (the automated nature of CANDU reactors being the most obvious; human error was perhaps the most significant factor in the NRX accident). The other was, I would say, minor in comparison, where at NRU a fuel rod caught fire while being removed from the reactor, but it was fairly well contained. Canada's been a world leader in nuclear power, especially safety, since the very inception of the field. I just wish of my fellow citizens were less paranoid about nuclear power so they could realize that (a) we're doing it right, and (b) we can be very proud of our accomplishments in this sector. As for the US...our reactor designs are fundamentally different so that's a tough comparison. In some ways I would say that the US has been far more lax in their regulations, and more stubborn. They seem pretty bent on only using LWR designs.

Almost never, but they're drastically tested on a regular bases.

War or disease, this scenario would define certain workers as essential. They (or replacements) would be available to maintain water supplies to the irradiated fuel bay. Any source of water will do. The provincial emergency operations centres (with federal support) are more than capable of providing portable pumps. CANDU spent fuel bays tend to have lower heat demands due to the spent fuel being natural uranium rather than the enriched fuels of other designs.

Yeah, and I would like them to elaborate how the controlled venting of radioactive steam is actually achieved...... rather than just take their word for it.... I like the video and the precautions, but some of it still comes off as shady with the lack of information they give in certain aspects.

Precisely @@MrKirk94 and Benjamin.

Depends on how bad the accident is. The answer is always as little as possible. If there's an over pressure in the containment building a controlled venting of SOME material is done to prevent a breach which will uncontrollably vent ALL of the radioactive material. It's a last case 'lesser evil' solution. Most simulated models put it days after a worst case accident so in addition to being limited they try to time them with evacuations and weather patterns.

India has only 5 PHWRs under construction and 10 that are "planned" but nuclear reactors plans in India are quite prone to being delayed or derailed like the 6 french reactors that got "approved" to be built in Jaitapur in 2009 but hasn't been built

Jaitapur power plant was a "White-Elephant", good that it's cancelled(unofficially). And for 10 planned reactors, site work has been started.

Nothing, you'd want to keep the spent fuel pool full.

Stop adding water for a bit

Hello Anoo, Risk is managed at all parts of the nuclear power plant life cycle: design, procurement, construction, operations and maintenance. The risk of an NPP drops considerably once the fuel is removed as part of the preparations for decommissioning. Risk is managed by the CNSC requiring facilities to have a management system see REGDOC-2.1.1 that is focussed on safety. nuclearsafety.gc.ca/eng/acts-and-regulations/consultation/comment/regdoc2-1-1.cfm

These Canadian reactors are designed to still have emergency mechanisms that need no power

Well yes but no , some generators were fine but the swichgear was flooded

@@bryankambuno6996 The back-ups on a Candu were built at ground level looking at the video not installed in a basement built under normal sea level like at Fukushima.

CANDU IS CANDU SAFE

"To me, considering the gravity of the possible impact: a safe nuclear plant would be automatic (or with minimal human intervention), grid independant and permanant shut down without melt down for neither the rod pool nor the reactor." Then you're looking for molten-salt reactors, Terrestrial Energy's IMSR being one example that's being developed in Canada (quite a few companies establish themselves here instead of the US because of some absurdly restrictive regulations around reactor development).

Lets hope these technologies get installed and/or our grids get secured before for instance a major solar flare happens.

Wont ever happen. Just like the elephant foot in Chernobyl is no longer melting anything because its concentrations of nuclear fuel are very low

You would probably have a major nuclear catastrophe on your hands. Probably a large part of North America would have to be evacuated

@@MusicGamesEverything Chernobyl had no containment at all and the elephant foot stopped. Why with all of the Candu precautions would it be worse? Also Candu uses natural uranium not highly enriched which means that after the heavy water is gone the nuclear reaction stops.

One shall do so as requested.

* How hot is the fuel before the accident? - Really hot * What temperature is ideal of the fuel after the accident? - Less hot * The emergency power generators what do they run on? - Diesel * How thick is the containment building of the power generator? - You mean the reactor? * Once meltdown fuel would fall onto the concrete slab.. how thick is that concrete slab? - Really thick * The radiation that is released... how toxic is this? - Depend how fast you run from the contaminated area

You have failed!

1. 260C but thats under extreme pressure to keep it like that. 2. 49C after is what they try to keep it at. 3. Jet Fuel, diesel and batteries. (4 jumbo jet props for the main backup) 4. Thick, like 1.8 meters thick. 5. It would land in the fueling duct, same 1.8 meter thick. 6. They filter it and can scrub 99.9 percent of radioactivity through it if they had to do it, but it would never get to that point.

That was pretty much a situation unique to Fukushima. Nearly every other reactor in the world is built on ground water can't reach and/or has a superb flood abatement design. Since Fukushima everyone's double checked their plans and made changes where a very few mistakes have been found. Water ingress of all types is a well known issue and should have been easily spotted at Fukushima, it probably was in fact, but the regulators in Japan are extraordinary slow and largely toothless. Now every reactor in Japan has a tsunami wall that can stop anything, high ground redundant power, waterproof electrical areas, passive controlled cooling reservoirs, etc. But they're closing the barn doors after the animals have run out.

I am thinking that putting a battery backup, and a generator backup system in a basement below ocean water level on the ocean front might not have been a brilliant engineering idea.

Nice.

If anybody selling you something, that is 100% safe, run away,... there is no such thing,.. we are just about 99,999999% save,.... every 9 at the end multiplying building cost exponentionaly.

Just imagining that ironic steam safety system: Using the heat from the meltdown to drive a steam engine, to pump water onto the radioactive core. That is basically how a nuclear reactor works! So when a nuclear reactor catastrophically fails, it becomes a mini nuclear reactor

Hmmmm let see, Canada has the oldest Candu and the biggest working reactors in the world. Maybe Romania's problems were caused by people who maintained the units. ie: Romanians

While, the CANDU and VVER are very different designs, in practical terms, they are equivalent in terms of safety.

VVER is comparable to PWR,...

Hello Erika, The filter will capture greater than 99.9% of the iodine, cesium, and strontium. Noble gasses such as krypton and xenon cannot be filtered out. Tritium will be partially filtered out.

@@cnscccsn And aren't the radioactive noble gasses not that big of a deal anyways since they quickly disperse and can't bioaccumulate?

Not even close. RMBK used enriched uranium as fuel, graphite blocks as moderator and a light water coolant. Also had a poor design on their control rods and active shut off rods (requiring power) CANDU uses natural uranium fuel, D2O moderator and D2O coolant. Passive shut down systems not requiring power to activate. The thing they do share is a positive void coefficient but the RMBK design is far worse for reactor criticality.

RBMK is really good reactor in his class. Never go accident until you start messing with him. Just keep the buffer inside. If you shut-down water-feeding for BWR or PWR....both will explode from the pressure.

I know I was joking

@@user-zp2ek7kp8r Right on. :-). And that is funny...

I’m use to bwr and pwr so not use to this Canadian stuff

what happens if the firetruck explodes next to the calandria?

Oh, people do. In fact there's a company based in Canada, Terrestrial Energy, that is developing a molten-salt reactor right now. They'll start with uranium, but they do have their sights on thorium fuel down the line, with the benefit of being able to burn "spent" uranium fuel from other reactors. Who knows, maybe in the future we could buy "spent" fuel from the Americans on the cheap and then use it to make energy...and sell it back to them at a profit... www.terrestrialenergy.com

They use different fluid. The heat transport system, the loop associated with the reactor, utilizes heavy water in part due to its role as a moderator. Having an isolated loop is also important for containment purposes-- contamination doesn't get transferred to the conventional side of the plant, including the turbine. The feedwater loop, the one that is on the shell-side of the boiler and used to spin the turbine, uses regular old light water. It's the preferred coolant because it's more abundant than heavy water, cheaper, and much easier to replenish.

verrin kindly elaborate

I thought I did. What in particular do you need elaborated?

+cnscccsn I do understand that. I was just wondering in the highly unlikely case it happens and the core touches the water what would happen. or is the water under pressure as in a car radiator? stupid comparison but for the sake of understanding :)

+cnscccsn the molten core I mean. think that's rather important

Mike G well you could use fire trucks to supply water to the calandria

Proce that would stop the accident

It'd be like lava falling in the ocean, you can see lots of videos of that, it's not really explosive. The fears of a second steam explosion at Chernobyl were wildly overblown. That calculation predicting it was from assuming the entire theoretically possible thermal energy of the core ended up in the flooded basement all at once. Which if possible would indeed have been really bad... But it had already lost much of it's energy by that point and was just slowly dribbling into the basement as it melted the piping and floor a bit at a time. Their math wasn't the worst way to play things safe at the time in 86' and it was probably a good idea to send those three guys down there anyway, the water was probably going to become a small hazard in other ways. But in hindsight with careful calculations it's pretty silly to think that the reactor was going to super-heat the basement a week after it'd already melted down and spread out.

Are you sure?

In Fukushima they had steam from decay heat pump the emergency cooling around on reactors 2 and 3, for a while it worked too, but eventually other problems overwhelmed the situation. There was no electric generator in the mix, just a turbine coupled to a pump, it was one of the emergency backup systems.

They are only like that in the video. In the real world, the stand by generators and emergency power generators are widely separated. All the elements of Shutdown System 1 and Shutdown system two are separate. They run off different power supplies, they are geographically separated in the plant, so a fire shouldn't damage components of both and they are made from different components from different manufacturers to prevent a common mode failure.

"I have a question though in candu reactors does inserting the fuel rods or the poison system cause an increase in thermal energy for a brief moment?" Nope. That's something very unique to the rather terrible design of the RBMK: canteach.candu.org/Content%20Library/19910101.pdf

The containment structure, where there is a risk of hydrogen build up in the event of an accident has a system of hydrogen igniters which will ignite any hydrogen present to burn it off before the level gets high enough to be hazardous. They also have passive catalytic re combiners which will get free hydrogen to recombine with oxygen to form water.

Mandate The Canadian Nuclear Safety Commission ... disseminate objective scientific, technical and regulatory information to the public.... If your mandate is disseminate objective scientific, technical and regulatory information to the public - should it not include dissemination of information of alternative technologies that could be magnitude safer than the existing technologies? With less chance of nuclear proliferation. With much less radioactive waste, that last only for 100 years instead of 1000 years? And with abundance of thorium to be used?

There is a Canadian-based company, Terrestrial Energy, that has been developing an MSR design for a few years now, actually. One of the primary reasons they are based here and not in the US is specifically because regulations here do a lot more to allow for innovation, which is sometimes paraphrased as Canada saying "prove your reactor design is safe" instead of "prove your LWR design is safe". Terrestrial Energy's IMSR has a lot of potential. It is being designed with the thorium fuel cycle in mind for future use (the plan is to start with uranium though). They plan for production to essentially be similar to an assembly line (think airplane manufacturing) to drive down costs, and for the self-contained units to practically be plug-and-play at industrial facilities, to provide heat for any number of uses, including power. Personally I hope for a day in the near future when Canada will start buying "spent" fuel from American LWRs to burn in IMSRs, and then sell the energy back to them at a profit. That'd be fun.

@@BlueArt2001 As someone with a materials science background, I am deeply interested in molten salt reactors, because it's my field that's holding everyone up. The physics works. It's the damn materials that holds the thing that need to be improved last I checked. Think about how your car fares after a winter of driving on salted roads. If you make the salt molten, it'll be many many times more corrosive.

SCRAM work without power when electromagnet lost his power. A scenario in this movie happen if there is NOT humans in the nuclear power plant. But STILL this isn't safe desing like LFTR...uranium is the problem.

wonniewarrior they added water to the chalandria and it was all fine

Probably very little. If they held off the zombies for even a few days they'd have achieved cold shutdown. The control system will be a brick in just a few days without maintenance and valves will rust in months. After that it's just a pile of concrete with some interesting metals on the inside. With all the security at a nuclear power plant it'd probably be a great place to hide out. With basic survival skills you'd ironically have access to everything but electricity.

CANDU is very young, when Fukushima BWR are from 60's..

Actually the history of CANDU is older. The design basis of them is from ZEEP, which started operation just after World War II. The very first CANDU reactor was the Nuclear Power Demonstration; it ran successfully from 1962 to 1987. We've just been nearly-paranoid about reactor safety since the accident at NRX. A ton of lessons were learned there and the principles developed from that are evident in every CANDU reactor since, the most obvious being redundant, fully-automated safety systems. Human error was the greatest contributing factor at the NRX accident, having both started it and led to it worsening greatly within seconds. The sheer speed of the accident made it very clear that humans are just too damn slow to be trusted with those safety systems, and far too unreliable to be trusted to manually operate critical systems without the system blocking them from doing something stupid.

Fire tucks were dispatched almost immediately. But that tsunami killed 15,000 people and wiped out infrastructure dozens of kilometers inland. There weren't any roads for them to drive on to get to the plant.

That's in the pool. After that they can go into dry cask.