CANDU Reactor EXPLAINED in 5 minutes

[@Dee-0015]

100% down to watch a 2 hour video of the safety features of the CANDU reactor!!

[@OsamaBaig]

Yesss!!!

[@juillotine]

+1

[@billgarland5395]

Well done! Small niggle near the start of the video: Deuterium is not heavy water. Deuterium is the heavy hydrogen in heavy water.

[@christofferravn4486]

Thanks for an amazingly easy understandable explanation of CANDU. I’d love to hear more about nuclear tech in the future from you 🙌

[@OsamaBaig]

Glad you liked the video Christoffer! Grateful that your taking the time to watch these videos

[@nekomasteryoutube3232]

I really do enjoy living between two CANDU reactors in Oshawa, I got Pickering AB and Darlington.

[@OsamaBaig]

Same here, its super convenient if you ever want to visit either site

[@mrevilmunkey_87]

Excellent video, making my nuclear studies easier to break down! I've subscribed to the channel and will catch up with other videos as and when I can! Thank you!

[@uzairanwar898]

Osama, I am new to nuclear industry and love watching your short format overview videos to get me up to speed with the reactor concepts and terminologies. I hope you can make some longer format videos that go in to more details of the concepts you have already introduced. Like: is the spent DUPIC fuel used by CANDU reactor innert and easier to dispose of? How do the safety features in the reactors work? How are medical isotopes extracted from reactors? Etc Oh, and I'd love to see more visuals of the stuff you talk about. Like instead of verbally explaining the construction of reactor, you couod do a simple sketch. Visuals help. Thanks for making this content. I am surprised you dont have more views.

[@mohsinalisiddiqui3231]

Great to know about this unique Canadian Reactor Technology. Also, I love your shirt! ♥ Keep going Osama 👌

[@OsamaBaig]

Thanks Mohsin, My Aunt got me this shirt for my Bday! I'm happy you enjoyed learning about Canadian Nuclear reactors, more informative videos to come ! Always appreciate your support

[@devashishkamble7215]

Best video i ever seen about reactor Very very good explanation ☺️ Thanks for making such type of informative videos

[@one.darkstar]

I had a doubt about how it would all work when the moderator and the fuel are separated by pipes, but after watching your video I understood it, thank you! (because it's made of Zirconium alloy which allows neutrons to pass through and so the moderator could help in slowing them down)

[@Hazmatt3446]

I want the two hour video, Osama! 👍🏻👍🏻

[@OsamaBaig]

Haha working on it!

[@acharya23]

Great video explaining CANDU technology especially for the casual people who are interested. Will be sharing with ppl! Keep up the good work.

[@OsamaBaig]

I'm glad you'll share the video Saurabh, thanks!

[@GenerationAtomic]

Awesome video! The CANDU is a Gen 4 reactor we have TODAY

[@OsamaBaig]

It impresses me to this day that this reactor was designed over 60 years ago. Thanks Generation Atomic! I really appreciate your support

[@thomascheney6083]

Similar in some ways in terms of passive cooling. Ideally, a gravity larger water supply to refill the vault and the Calandria would be beneficial until the reactor could be air cooled. I know there has been some research in to Accident Tolerant Fuel for Candu's but this would require mild enrichment.

[@OsamaBaig]

@@thomascheney6083 Interesting thoughts. Lots to learn about CANDU for me. I really like the thermosyphoning feature in CANDU

[@JoseMolins]

Good fast review! Thank you Osama

[@OsamaBaig]

Its my pleasure, thanks for watching Mol!

[@kosmosthegreek]

Wow thanks for the video. Explains it so thorough and simple so anyone can understand

[@OsamaBaig]

Appreciate that feedback Kosmosthegreek, thanks for checking out the video!

[@Berkana]

Osama, I have a question. Why are the channels in the calandria arranged to fill a circle? (1:04) Why aren't they arranged to fill a square? Their packing arrangement is in a square grid rather than a hexagonal grid. It would seem to me that the same space could hold more channels if the fuel channels simply filled out the corners as well rather than forming a circle. There does not seem to me to be any reason why that reactor arrangement would have to be circular. An alternative packing that would still permit control rods to be dropped in could be hexagonal, with the over-all pack forming a hexagon (turned so the two sides are vertical, and the top and bottom are sloped-basically a hexagon with one corner pointed up and one pointed down). Basically my question is about why the calandria channels are packed the way they are, and whether there are any advantages to be had by arranging the channels differently.

[@OsamaBaig]

Good question! There is probably a bunch of reasons why 1) Ease in manufacturing 2) Ease in assembly 3) Ease in maintenance 4) Nuclear Reactor Efficiency (Calculations are done to understand Nuclear reactor Kinetics and what is the ideal shape considering the fuel type, moderator and materials being used)

[@sethapex9670]

CANDU reactors also have an element of passive safety in that if the reaction gets too hot the heavy water can boil and no longer moderate the neutrons.

[@OsamaBaig]

Yes Seth great point, also CANDU's can Thermosyphon. This means, if the reactor shuts down and back up generators don't turn on. Through convection, the reactor is able to cycle coolant within the core. This is a really cool passive safety feature

[@emilgrigorescu8282]

@@OsamaBaig A feature that you don't want to use!

[@timtarbet4594]

A pretty cool reactor system, but I’m honestly skeptical about any solid fueled reactor system because of the build up of fission products that poison the rod WAY before the fuel has been used up, which in turn necessitates complicated and expensive reprocessing procedures. I probably sound like a broken record at this point, but it seems like liquid fueled reactors (be they thorium or otherwise) have the advantage because the elements that would poison the reaction either boil off or can be precipitated out chemically, which has the added bonus of providing you with pure isotopes that can then be used in other industries, such as medicine.

[@OsamaBaig]

CANDU is a GEN II reactor design, its pretty remarkable for 60 year old technology. There are studies by Moltex going on to find ways to reprocess CANDU spent fuel. These can then be used in breeder reactors. I agree Tim, liquid fueled reactors have a lot of advantages. It would be great to see some demonstration reactors developed based on these designs. Can you point to any design names? I'd love to research more about these liquid fueled reactors

[@thomascheney6083]

@@OsamaBaig There is also Terrestrial Energy.

[@OsamaBaig]

@@thomascheney6083 Yes, fantastic Canadian company that is focusing on MSR's. Do you have any resources that point toward their unique reactor design?

[@OsamaBaig]

@@thomascheney6083 Absolutely, they have a wonderful design

[@jimgraham6722]

Agree, it was a great safe design for its time.

[@burkiescorner1891]

Awesome Video, very descriptive and simplified

[@OsamaBaig]

I appreciate the feedback Burkie! Hope you get a chance to check out some of the other videos. Also is there an aspect of CANDU tech you are interested in knowing more about or seeing a video on?

[@faizancooks]

Flawlessly edited and explained!!! Amazing work 👏👏

[@OsamaBaig]

Thank you Faizan!! Your KZbin videos make me so hungry every time, and especially miss your cooking. Keep up the good work

[@wesmaksymetz6144]

How small can a candu reactor be. For example are there reactors that can power a small city or a hospital?

[@arkham8807]

The Candu reactor is the RBMK reactor that worked! It has many similarities, and it is much safer!

[@alexanderivkin7086]

YES! I love the CANDU, IMO the best water reactor ever. Greetings from Germany, a country, that soon will be in stone-age again.

[@OsamaBaig]

A lot safer! Although they both use fuel channels, the heavy water moderator/coolant is a much safer feature. It also has SDS2 that uses chemical agents to remove neutrons, a feature Chernobyl didn't have.

[@OsamaBaig]

@Alexander Glad to see German support here. Hopefully things can change in the near future. Korea is also having a major comeback with Nuclear energy, I'm optimistic about Germany. Do you think Germany would ever change its mind? I'm curious

[@alexanderivkin7086]

@@OsamaBaig Not before 90% of its leftist dumbass sheep voters were forcefully re-educated through massive electricity shortage. And it will come, next winter its a 99% chance, in Winter 2022/23 the chances are 100000000%.

[@BasementEngineer]

@@alexanderivkin7086 What happened?

[@Phil-D83]

Because they can be refueled while operating, also excellent design to make ISOTOPES and weapons grade material.

[@OsamaBaig]

Philip I agree with you on the medical isotopes, but In terms of weapons, its very difficult to make weapons grade material using power reactors. The entire purpose of power reactors like CANDU is to maximize economic energy production, which means leaving fuel inside the core for long periods of time. Contrasting to reactors that produce weapons grade material, since they need to shuffle fuel fast enough to prevent other isotopes of Plutonium from being formed. CANDU's and reactors that produce Plutonium from weapons work very differently

[@Phil-D83]

@@OsamaBaig without the iaea safeguards, they are excellent for making weapons grade material. India made it original nuclear bomb with an old candu reactor.

[@leerman22]

@@Phil-D83 It's really easy to get "boom stuff" out before getting spoiled if you don't have to keep shutting off the reactor.

[@johnpeacocke2112]

@@leerman22 That wide core of tubes can show many levels of neutron flux . It is true that a fuel pressure tube could be used with the right source material for the right length of time and at the optimum flux to produce , for instance, Plutonium. Security is so important.

[@OsamaBaig]

@@Phil-D83 Actually India made an nuclear weapon with CIRUS which wasn't a CANDU reactor. It was a research reactor built by the US, and the heavy water was supplied by Canada. It would be extremely difficult to produce weapons grade plutonium with Commercial electricity producing reactors since you would need to shuffle fuel very fast, and it would make the process of generating electricity difficult.

[@Bimmerguy7979]

great stuff! Well done

[@OsamaBaig]

Thanks Gino! CANDU is such a innovative reactor design. I hope its not forgotten about in the next few decades!

[@dusk6159]

Still a great video, you explained it in the finest way

[@OsamaBaig]

Glad you think so Dusk! Thanks

[@balmeyra]

Good video! and thank's for the explanation!!

[@OsamaBaig]

Thanks Balmeyra!

[@waywardgeologist2520]

How small can one make the reactor?

[@OsamaBaig]

As small as you want. A research reactor like the Slowpoke is the size of a football!

[@mayurg5327]

How it works ?? Didn't explained thoroughly my friend control rods steam generation , n all that

[@Atricapilla]

Hi Osama. Do you know if any work is being done on the SCWR (CANDU) reactor?

[@OsamaBaig]

Hey Atricapilla, I recently read an article on the SCWR technology published by CNL. I recommend checking it out, the technology seems interesting pubs.cnl.ca/doi/full/10.12943/CNR.2016.00042

[@dodaexploda]

I would watch a two hour video on CANDU safety.

[@OsamaBaig]

I'm getting tempted to make one now! Thanks DerekDotD!

[@Kajanifoe]

Nice job!

[@OsamaBaig]

Thank you Andrew! Hope you get a chance to check out some of the other videos too !

[@married2chronicandcoffee]

How come we dont have more of these operating?

[@AlldaylongRock]

@john N CANDUs are much more fuel efficient than LWRs. They are really a "poor man's reactor" which technically isn't bad. An ideal nuclear program shall start with LWRs to produce deuterated water, and you stockpile the used rods. Then you build CANDUs, fill them up with the produced heavy water, and processed used rods from the LWRs. You can throw some thorium in for good measure, and kinda use it like a "breeder" to obtain U233 to use in the LWRs, phasing out enrichment facilities.

[@AlldaylongRock]

@john N That's where Fukushima comes in. They are extracting all the "Nasty Things", leaving only deuterium (not radioactive), and tritium, which is so diluted that it's impossible to extract viably. So there's definitely technology to do so, and being dual use (mitigation of effects of a meltdown, and being usable to purify HW) is nice. The design modification involves using less HW (I think it only uses HW inside the calandria tubes), that's why it needs 2% EU.

[@AlldaylongRock]

@john N Still less waste than what you have to deal with for comparable amounts of energy from wind or solar. The technology to make nuclear "waste" basically irrelevant is here already. We are not using it for political reasons.

[@AlldaylongRock]

@john N Same can be said about other energy waste. You know old PV panels are hazardous waste, right? That cost more to recycle than they are worth. Or that wind turbine blades are not recycled, and emit microplastics into the environment. Nuclear "waste" on the other hand, is the only energy waste that is thoroughly accounted for.

[@AlldaylongRock]

@john N Unlike a coalar panel that spews out heavy metals that never decrease their toxicity?

[@ThomasJeppesen]

Can you make a video about the CANDU fuel cycle, including the use of thorium and waste fuel from other reactor types? No need for constraining the video to 5min, please! :P

[@OsamaBaig]

Hey Thomas, of course! That would be something very interesting I'd love to make. My strategy on this channel is to cover general topics, next stage would be to move onto nieche items. Your input is super valuable in helping me understand what viewers are interested in seeing

[@Berkana]

SMRs have gotten a lot of attention lately for various claimed benefits; would it be possible to build an SMR version of the CANDU? Looking at this presentation of yours leaves me with some questions. Is the heavy water the stuff that's boiling and turning the turbine? What is the working fluid of the engine? Also, you mentioned that heavy water has a deuterium atom. Is that just one, or are both hydrogen atoms of the heavy water molecule deuterium atoms?

[@OsamaBaig]

Berekana, I believe SNC lavalin publically announced a SMR version of the CANDU reactor. I believe it was a CANDU-3 design that also produced isotopes while operating. Also, heavy water is not used for the turbines, the turbines are located on the secondary side which use steam (light water). Also, there is no "Engine" its simply Pressurized tubes that Heavy water flows through, gets heated, which is then transported to heat exchangers which help create steam on the secondary side. Hope that helps :)

[@JJs_playground]

4:45 I guess now we should call it the "Tesla of nuclear reactors"

[@OsamaBaig]

Haha nice comparison!

[@davidwilkie9551]

Thanks

[@aitorinarra]

Isn’t candu much more expensive to build that conventional plants?

[@OsamaBaig]

That's a good question Anton, I'm not too sure to be honest. I haven't looked at the average price for a PWR/BWR and CANDU and compared what is out in the current market at the moment.

[@aitorinarra]

@@OsamaBaig i heard in another video that the initial investment for candu plants is much more expensive than PWR. But yes, this is the solution to global warming and energy in general. It's too bad general public still have negative option about nuclear

[@BasementEngineer]

I'm not so sure than an apples to apple comparison was ever done, comparing CANDU reactors with other nuclear power plants. One of the difficulties with CANDU plants is the length of time for manufacturing and construction; this is a real financial penalty at times of high interest rates as was the case with the Darlington power plant construction. Add government interference into the mix (now we need it, now we don't) and the costs accumulate. The completion of the Darlington power plant was severely affected by the provincial government of the day, driving up costs at a time of very high interest rates, the early 1980's. This of course is offset by the plant availability percentage. CANDU power plants are re-fueled while running at full power; thus lengthy re-fuelling shut downs are not necessary. The rest of the plant is designed such that maintenance shut downs were necessary only every 5 years or so (this was in the early 1980's). I recall that the primary coolant pumps' seals and bearings were the main difficulties here. I think that over the life expectancy of the plant, costs are comparable. Costs are lower than with fossil fuelled plants because of the very low cost and quantities of nuclear fuel per KW-hr of electric power produced, especially with CANDU fuel.

[@karaal44]

Interesting.

[@OsamaBaig]

Happy you found the video interesting Mateusz!

[@stickynorth]

I'd love an update video on how the US is being squeezed by Russia because of its lack of domestic nuclear fuel production for its reactors vs Canada which must be laughing all the way away from the World Bank since it's not dependent on enriched uranium to be powered... Another video idea? How and why America should add CANDU reactors to it nuclear fleet for this same reason... How using CANDU reactors could truly make America energy independent! Or how about a video on the CANDU Monark 1000 reactor design which is being pitched for Bruce... Or a video on how the Canadian buyout of Westinghouse nuclear might help launch a new generation of reactors in Canada and across the world... Just some thoughts! Love your channel!

[@battistazani8202]

Well, Rbmk too could swap fuel on the fly..

[@OsamaBaig]

You got that right, RBMK also has online refueling capabilities

[@samanthamonaghan7579]

My only issue is that SNC company has some questionable stuff.

[@alexandrucatana5080]

Briefly here you are CONTROL/SHUTDOWN Systems. CONTROL SYSTEMS: 1. Zone Control Units-ZCU (14=7+7) consisting in 14 volumes of light water (H2O) assures fine control of reactivity.Provide pozitive and negative reactivity rezerve. 2. Ajuster rods (21=5+3+3+4+2+2 banks) which in normal operation are fully inserted Provide pozitive reactivity rezerve, flaten neutron distribution in reactor core 3. Mechanical Control Units (4=2+2) are in normal operation fully extracted. Provide pozitive reactivity rezerve. Control systems (mainly ZCU) are used (via DCC=Digital Control Computer) for reactor power increase/decrease, setback, etc. SHUTDOWN SYSTEMS: 1. SDS1 (Shut Down System 1) consisting of 28 vertical bars is used for emergency situation. High negative reactivty. 2. SDS2 (Shut Down System 2) consisting in a number of horizontal nozles to ineject liquid poison. Very high negative reactivity CANDU safety operation is assured by 5 (five) systems.

[@mohitnarula9880]

Preassurized water reactor

[@OsamaBaig]

PWR Explained in 5 mins? Next video Idea I've thought about making

[@mohitnarula9880]

@@OsamaBaig thnx

[@OsamaBaig]

What is one part of a Nuclear Reactor you've always been curious about? (For me its always been the topic of Nuclear waste)

[@mohsinalisiddiqui3231]

+1 Proper Nuclear Waste Management and Disposal needs attention!

[@EricMeyer9]

The day-to-day of a nuclear worker

[@EricMeyer9]

The crazy level of security at a nuclear plant (not sure if this is as true in Canada as in the US)

[@OsamaBaig]

@@mohsinalisiddiqui3231 Its a very interesting topic. Nuclear waste is managed in very safe way. I can't wait to create a video on this topic

[@OsamaBaig]

@@EricMeyer9 "Day in the Life" videos are the best ! I want to get an operator to show his/her day in the life. Let me see if I can find a friend that's willing!

[@zoyascrazyart6014]

Cool

[@OsamaBaig]

:)

[@sethapex9670]

In an apocalyptic scenario, if someone found a source of natural uranium, and knew how to produce heavy water, could they build a small scale CANDU?

[@sethapex9670]

@@fraserhenderson7839 I don't see what is that complex about it. Just build a tank of heavy water with channels through it for the fuel rods. The fuel pellet fabrication is probably tricky but the natural neutron economy of the heavy water should be sufficient to sustain a reaction.

[@billhickswasgreat3421]

"most safest" triggered me a bit. Cool video though!

[@OsamaBaig]

Haha I meant to say "One of the most" ! Out of Gen II reactor designs, which design do you feel is the safest? I'm curious to get your thoughts on this. Thanks for sharing your triggers Georgi!

[@spencerleava2502]

CANDU reactors are so lols. Some of you may cringe when I make the comparison, but I describe them as being like RBMK reactors except the designers built them with safety in mind. They even have a positive void coefficient. Now that may have raised some red flags for some people, but the genius of CANDU is it's mediocrity. Because it doesn't use enriched uranium, it's slow to change its power output and barely works. To get everything to work properly, you need to set everything up in just the right way: screw anything up and it will simply stop working and shut down. Because it's slow, it's easy to identify problems before they get out of control. Because the uranium isn't enriched and needs heavy water, adding regular water shuts it down. Because the control rods need power to be kept out of the reactor, a loss of power drops them and shuts it down. And my favorite, because everything needs to be spaced up and aligned in just the right way, if the fuel channels get to hot they actually begin to warp and sag. This breaks the alignment and causes the reactor to shut down. Basically, when most reactors get started, they mainly sustain themselves and operators need to make sure everything stays under control. With CANDU reactors, operators need to put effort into just keeping the thing on XD.

[@OsamaBaig]

Countries like China, South Korea, Argentina have made major investments in CANDU reactors. Romania is building a few more units as well just recently. If the reactor design was so horrible why would these countries purchase CANDU technology?

[@spencerleava2502]

@@OsamaBaig I think you misunderstood my comment. CANDUs are actually my favorite reactor. When I describe it as a mediocre reactor, its a feature not a bug. It doesnt do anything fancy, it just does an OK job at wide range of things. This is really all you need for a baseload power role, and its versatility mean you can easily fit a CANDU into a grid that uses a bunch of other reactors and really get your moneys worth. A good example of this is the Qinshan Nuclear plant, where they have 5 CNP reactors which use enriched uranium, and 2 CANDU reactors. They can take the spent fuel from the CNP reactors and use them in the CANDU reactors. With most other reactors you set up ideal conditions for fission and then need to watch it carefully. Because they used enriched fuel, you can really get it going. In the rare event there is a major problem, you need to shut down the reactor and get everything under control. If people screw up in how they handle a situation, things can get nasty. Because CANDU uses natural uranium, they need to go the extra mile just to allow fission to occur. The thing barely works, and you need to make sure everything is nicely put together just right for it to work. Because it barely works, its really hard to screw up. In the event of a problem, a CANDU reactor will most likely shut itself off. If people screw up in how they handle a situation, the reactor will probably just break and shut down. If you are wondering how a reactor that barely works can compete with the spicier designs, the answer is simple: CANDU reactors are huge. Most of the reactor is simply a bunch of smaller prefabbed components stacked together. You would think that a massive reactor would be harder to build, but for CANDU its not the case. One of the perks of the design is that a country can lack a highly developed industry, and still realistically manufacture most components domestically.

[@BasementEngineer]

@@spencerleava2502 Much of what you say is true; its the spin you put on it that is objectionable. How can something that does exactly what you designed it to do, be mediocre? Further, I have never heard of one instance where a CANDU unit failed to achieve criticality. Agreed that there is much finicky machining detail in Candu units, hence the need for a well-trained work force along with a management style that reinforces personal responsibility and actions. Yes, CANDU reactor assemblies are huge, and the Darlington units were just short of 600 tons. But we got them to the site in record time and well within budget. The Candu design was designed so that a country with reasonable industrial facilities but a well trained work force, could produce one. The heavy forgings needed for the pressure vessel reactor containments were not producible in Canada. The USA and others decided to tool up to produce these vessels, and were paid for by the military, as these wanted the nuclear by products for their weapons program. The CANDU reactors can, and were, built without any military contributions.

[@davidbeveridge8953]

Control Absorbers and Shutoff Rods are two different things.

[@OsamaBaig]

Good Catch, thanks for pointing that out David

[@davidbeveridge8953]

@@OsamaBaig No problem, good video!

[@OsamaBaig]

@@davidbeveridge8953 Thanks, its another great video idea. Identifying the difference between the two!

[@arijitbanik7597]

Terrific 👍 + CANDU is perfect for harvesting of cobalt-60 for sterilization of medical equipment globally.

[@OsamaBaig]

Thanks Arijit! Yes its an incredible resource for Cobalt-60!

[@youcantata]

Con of CANDU: it uses natural(0.7%) uranium. It needs frequent fuel change. and generates large amount of spent fuel and unburned fuel, i.e. nuclear waste. Nowadays enriched uranium is cheap. So to reduce nuclear waste, new reactor should use 20%-enriched HALEU uranium, not 4.5% LEU or natural uranium. Less fuel change, better fuel utilization, less spent fuel waste.

[@OsamaBaig]

Youcantata, the CANDU is a 2nd generation design. Cost of enrichment was a lot higher when a majority of CANDU's were being built across the world. However, as the cost of enrichment has dropped throughout the years, there are benefits to using higher enrichment. The new 3rd Gen CANDU also uses slightly enriched uranium.

[@BasementEngineer]

The frequent fuel changes, continuously in fact to optimize burn-up, is a non-entity because refuelling is carried out at reactor full power. Large amounts of spent fuel? Compared to what? Furthermore, new CANDU fuel bundles can be handled without special transportation, and spent fuel bundles can be removed from the water cooling bay after 10 years for dry storage above ground.

[@grantchang81976]

CANDU save us from ourselves.

[@rayrays96]

All reactors use heavy water buddy

[@OsamaBaig]

umm...no not all reactors use heavy water. Most power reactors use light water

[@prashantbaghele9449]

😁😁🤘

[@Ashwin_051]

thank you for 6 marks

[@lexxgruzovik]

Candu has the same positive void coefficient as RBMK in Chernobyl had, they are dangerous by design…

[@OsamaBaig]

Oleg, I agree RBMK had a dangerously high positive void coefficient. CANDU on the other hand is very different, as it has a very small positive void coefficient value which can easily be countered by control systems before any boiling occurs. It also has built in pressurizers which prevent boiling from happening in the core itself. Also, CANDU has several safety features which RBMK didn't have, such as chemical poison's, Liquid zone control (Lightwater that removes neutrons), and Emergency injection systems. There is a MASSIVE difference between CANDU and RBMK design

[@Megs125]

Canada needs to go back to investing in our public corporations because a public service invented this reactor and sold it to so many other companies. The amount we charge OPG for stupid shit is astronomical.

[@sergejadam8860]

CANDU Reactor is a scam reactor