Jump to content


  • Content Count

  • Joined

  • Last visited

Posts posted by rikko

  1. PWR_Layout.jpg


    Turns out I can't be arsed to draw a picture but google can provide some useful ones.


    The reactor is continuously heating water (called primary coolant), this water is pumped into the steam generators. The energy is tranferred from the primary coolant into the steam generator water (called secondary coolant) which is boiled. This reduces the temperature of the primary coolant which is then sent back into the reactor to be heated up again, ready to repreat the process again.


    The secondary coolant is boiled and turned into steam, it is a high pressure steam. This high pressure steam is transferred to the turbines, where it is forced through spinning them round. The turbines go on to either generate electricity from the motor generators or power the engines from the main gearbox. This process extracts all the useful energy from the steam and leaves low pressure steam. The low pressure steam then flows into the condenser.


    Cold Sea water is pumped into the condenser and is warmed up when the steam condenses. Warm sea water is then pumped out of the submarine.


    The steam that has been condensed is then returned to the steam generator to be turned into steam again.


    Here is the same diagram but for a power station.




    Notice that the only difference is the cooling tower instead of sea water. No steam is vented from either system.


    This whole process is described here http://en.wikipedia.org/wiki/Rankine_cycle


    Wolfy I trust you will now recreate these in crayon for Gemmill as you promised earlier.

  2. Ok. The steam generator makes High pressure steam. This steam flows through a pipe to the turbine. The steam enters the turbine at high pressure. The steam loses pressure (energy) turning the turbine and low pressure steam exits the turbine. This low pressure steam is condensed inside the pipe and fed back to the steam generator.


    At no point does it come into contact with oxygen. The 'venting' as you call it is done when the steam passes through the turbine.


    Inside your pressure cooker there is water. You apply heat and some of the water turns into steam inside it causing the pressure to rise. If the pressure rises too much the relief valve will lift releasing the steam inside. This drops the pressure and the temperature inside the cooker drops too. The valve will then reseat and the pressure will rise again. The steam is made inside the cooker in the absence of oxygen.

  3. Against.


    Death isn't a punishment it's a cop out. Would you rather be dead or locked in dank cell with no contact for the rest of your life? True punishment is being forced to live for the rest of your natural life with guilt and remorse. Or if you are heartless sociopath then its being totally isolated and being frustrated by no one listening too or caring about you.


    To my mind death penalty only works if you have a strong religious faith where god punishes you in the afterlife but as I don't believe that it's a cop out.

  4. Exactly. The whole point is a sealed unit, yet it has to run through a turbine to OUTSIDE air, even for a small period. It is still venting/exhausting.


    Yes now on the sub you substitute air for water. You pump that cold water into the sub. Use it to cool the pipe containing the steam thats come out the turbine. This condenses the steam inside the pipe which is then pumped back to the steam generator to become steam again. The sea water which has been heated by cooling the pipe is then pumped out to sea again.


    This process is happening continuously while the the sub is running. Power stations do the exact same thing.


    You had it right in your previous post.

  5. Point 1 - you don't need oxygen to make steam. Just need water and heat. The amount of heat depends on the pressure the water is under nothing else.


    Point 2 - if you then added a pipe that collects all the steam that's come out your radiator and through your turbine and run the pipe in the outside air for a bit to condense it again and feed it back to the radiator you will be fine again as your filling it with water as fast as you are removing it! You're fuel economy won't be so good anymore though because you are using energy from the fuel to heat the radiator to make the steam to turn the turbine.

  6. It still has to be condensed right?


    To condense it, I assume the submarine would have to continually allow sea water in for this process to happen right? And going by that, it would also have to be pumping the hot sea water out and so on and so on, correct?


    All this can be done whilst keeping the original water sealed, sort of like a combi boiler radiator system in your house, under pressure constantly, unless there is a leak of course.



  7. Well done on your sports car.


    Anyway. By your reckoning then, steam engines should not emit steam at all.

    Also nuclear power stations should not need massive stacks to vent steam, which they clearly do. Why is this if it can all be condensed back as efficiently as supposedly a sub does?


    Steam trains use a simpler less efficient open loop system so just dump the steam. It's one of the reasons they aren't used any more. Electrics and diesels are cheaper to build and run.


    Power stations and subs used a closed loop system and hence are still being used. The towers are huge on power plants as air is a very poor heat transfer medium (1000x worse then water) and they produce a lot more power then a submarine core does. Although if you look at the current crop of uk nuclear power stations none have these cooling towers. They all use sea water.


    If you want more read up on the rankine cycle.

  8. Back to these nuclear powered subs.


    It is said that nuclear power is just a glorified way of boiling water and if real, it would be correct because it just heats up, super hot we are told by miraculous fissioning.


    Now I'm on the understanding that to make something work, like a steam engine for instance, you cannot make it work unless something is vented one way or the other.


    You would be correct if the year was 1750. In order to increase efficiency and power the steam that was vented is now recycled and has been done so since the 1830s. Google the Carnot cycle and Rankine cycle for more info on that.


    We see how a steam train works by pumping the steam to drive pistons and is exhausted through the top as steam. I mean if it could condense the steam and recycle it back fully meaning no exhaust/outlet then you get no movement.


    After the pressure is taken out of the steam by the turbines (or pistons if you prefer) it is sent to a condenser to be turned back to water. This hot water is then sent back to the steam generator to repeat the process. The energy released by the condensing the steam is your exhaust and is transferred to the sea or via cooling towers to the atmosphere.


    So in a nuclear powered sub, the so called nuclear fusion super heats the water up which is sent to another part that turns it into steam that drives the generator and propeller and the used steam somehow condenses super quick and is sent back round to be heated again with no supposed venting necessary, even for the condenser...hmmmm. I'm having real trouble getting to grips with this mind.


    I'm still having trouble working out how they get spent fuel rods out of a sub to refuel without killing everyone in the vicinity of it, as we are told that spent fuel is highly toxic.


    That is why I get paid a fortune and drive a sports car and you get benefits and ride the bus.


    Edit to fix formatting. Forgot the codes and am writing this on my phone.

  9. To refuel a sub is a process that takes nearly 2 years. It's done by cutting a hole in the casing and pressure hull then taking the lid off the reactor. A bottom opening shielded container is bolted on top of it and a fuel module is raised into it. The container is then closed with spent fuel inside. Repeat until all fuel is removed.


    The submarine fuel lasts so much longer as it has a high enrichment whereas civil reactor fuel has low enrichment.

  10. I'm going guess the answers because it doesn't seem like i couldn't have a decent guess!, wouldn't mind seeing Rikko's explanation (not because i doubt shit like wolfy but because the explation on how the fuel worked in the other thread was interesting)


    1....What is the purpose of having TWO nuclear reactors on one submarine , why not just one as they apparently produce an enormous amount of electricity from the steam they generate which I would have thought would easily power something like a submarine.

    • I'm guessing it's the size of the reactors and the length of time they're "in service", they can stay out longer and use one when the other needs refueled without exposing where they are/were/have been, or they power different elements/work as a failover so a problem with one doesn't compromise the running of the systems.

    A nuclear sub can go 25 years+ without needing refuelled. Having a back up reactor is probably the real reason.



    2...When a submarine comes into port, how do they turn off the nuclear reactors in terms of them not producing any steam as I'm led to believe they take a lot of shutting down and cannot be shut down fully.

    • lobbed into some sort of standby mode because it's drawing less power? think stop/start for modern cars but on a complicated scale?

    Broadly right. The sub reactor has a feature called 'load following'. When you want to go faster you draw more steam out of the core so the temperature drops. When the temperature drops the water coolant and moderator gets denser causing the fissions to increase and more power is taken from the core. When you want to slow down or take less energy out of the core the reactor temperature increases causing the water coolant and moderator to expand which decreases the number of fissions. This is quite a complex idea to get your head around.



    3..In nuclear power stations, you see steam stacks that they say are used from the process of condensing , I was wondering how a submerged submarine manages this.

    • Maybe they don't need to get rid of the steam though, are subs not like a "steam engine" in the sense the produced steam is used to drive the propeller, so when it drives the engine that works the propeller it could equally get cooled, turned back into water and then go through the process again in a loop?

    That's broadly correct also. They use sea water to do final bit of condensing after the steam has lost its pressure turning the propeller and turning the electric turbines etc

    edit > re did the post to tag rikko

  11. FAO Rikko:


    I have a few questions for you.

    I read up on how a nuclear powered submarine works as in propulsion and was surprised to see that some have 2 Nuclear reactors.

    Now I know how I'm led to believe how they work, yet I have a few problems with it. I was wondering if you could shed any light onto it using basic speak that is understandable to myself and not scientific terms used to baffle.

    I'd appreciate if you could use your own words and not any copy and paste from sites as they can sometimes leave more questions than what they answer.


    If you don't want to, that's fair enough but here goes.


    1....What is the purpose of having TWO nuclear reactors on one submarine , why not just one as they apparently produce an enormous amount of electricity from the steam they generate which I would have thought would easily power something like a submarine.


    2...When a submarine comes into port, how do they turn off the nuclear reactors in terms of them not producing any steam as I'm led to believe they take a lot of shutting down and cannot be shut down fully.


    3..In nuclear power stations, you see steam stacks that they say are used from the process of condensing , I was wondering how a submerged submarine manages this.




    1. Some Russian subs have 2 reactors. The UK ones don't. I am fairly certain the USA and French ones don't either. I could guess why the Russians went for two but I can't say definitively as I don't know. Its probably down to redundancy or if they have multiple propellers/propulsors it may be for more speed. There are a number of reasons why you may want 2 over 1.


    On a side note US air craft carriers have 2 reactors on them and that's done as one core doesn't produce enough power for such a large boat. The US carriers are basically floating cities though, so it may be as simple as that for the russian subs.


    2. When a sub comes into port it will still generate steam which is used to turn the electric generators to power the lights, air, computers etc etc The reactor on a submarine powers everything from the toilets to moving the whole boat. To shut the core down for repair work or refuelling you insert the control rods all the way in which stops all the nuclear fissions. You then have the decay heat to deal with which is initially pretty high at about 7% of full power but drops down to under 1% full power in a few days. When you want to refuel you have to wait until the decay heat is less then the natural heat losses from the reactor, this can take 3-6 months to occur. The steam generators are used to do this if the boat is in the water. If its in dry dock they have an alternative cooling supply attached instead.


    3. They use the sea as a heat sink instead of a cooling tower.

  12. Sort of, except I simply think that Nuclear power in how they say it works is absolute bullshit. Not because it's complicated, it's because it's made complicated so the average Joe doesn't question it.

    In fact those who profess to be Nuclear physicists are merely working from written bullshit and those that actually work in the industry haven't a clue what they're actually dealing with, except what they're told they're dealing with.


    It's all full on secret squirrel for obvious reasons. That's my take on it.


    So you think nuclear power and weapons are simple, but those pesky scientists deliberately make it complicated to intimidate the general public. Rather then it just actually being complicated.


    Care to explain why they do this? What's their motive? Extorting money from the government? Or is it the government in on it and using it to extort tax money from the general public? What do they spend this extra money on?


    Is the fact its bullshit why the USA, UK, France and the other so called nuclear powers are desperate to prevent Iran getting it? Because Iran is in fact the saviour of us all and will expose the truth (whilst brutally opressing everyone who lives there). Also why hasn't the likes of North Korea exposed it as bollocks as they have successfully developed nuclear bombs? Are they in on it too?

  13. In other words, you have no reason to believe what you do. You just think that what others, each a specialist in their field, say is the truth is too complicated to be true? Yet you have no idea how any of it actually works and are unable to provide any credible solution as to how technology we have and use everyday actually works.


    So you prefer to believe in numerous massive conspiracy theories which are without doubt more complicated and reject the universally accepted solutions because in your words "well why not".


    Would you say that is a fair summary of your position?

  14. Here's your Nuclear reactor fuel rod assembly. As you can see, it's so dangerous, it can be handled without protective equipment and with the hands.

    One minute they are highly radioactive and the next they are emitting doses so low, it can be picked up and messed with. The beauty about official stories is, they can tell us anything because we haven't a clue and will just accept anything told to us, no matter how silly or illogical it sounds.


    These so called rods, after use, produce Plutonium as a by product for some reason and mixed with uranium , it apparently makes "WEAPONS GRADE" Uranium, which is extremely volatile we are told one minute, yet once assembled into a bomb, it's as docile as a new born puppy and you could probably run your tongue up and down it if you want.

    Yet slam it together and your city is toast.


    These so called Nuclear power plants do produce electricity , I believe that... but not by Nuclear but by the wastage of electricity which is then transferred through steam to generators , so in-fact it all looks and appears legitimate.




    Already answered most of those questions so I don't see the need to repeat myself.


    The fuel rods you have look like those used in a light water reactor, either a PWR or a BWR. The fuel used in them is pretty similar so I can't tell you which it is. There is lots of protective equipment in the photo. There is the integrity of the fuel cladding, the ventilation system, the lack of a moderator (this slows the neutrons) etc etc PPE (personal protective equipment) is the last resort for protecting people. When you go into an active area you basically wear the same outfit as the man behind the deli counter at morrisons and that's only there to stop you getting contaminated. If you go in an area with no contamination then you don't need any protective gear as in the picture above.


    You seem to be confusing spent nuclear fuel with weapons material. The stuff used in weapons has no spent fuel with it so is not highly active as I said earlier.


    In summary:


    New unused fuel: Essentially Not Active

    Used Fuel: Highly Active

    Weapons material: Contains no used fuel so is not active.


    Weapons grade uranium is for all intense purposes pure Uranium 235 it contains no Plutonium. Weapons grade Plutonium is for all intense purposes pure Pu239 it contains no uranium. You use one or the other. Not both.


    The scientific meaning of the word volatile means turns to a gas easily. Uranium and Plutonium, weapons grade or otherwise, is not volatile. It is fissile or fissionable depending on the specific isotope.


    If nuclear energy doesn't generate electricity what does? Wasted electric? To generate the amount of steam made in the nuclear reactors in the uk by electricity would take more electricity then the UK generates. Also how do the submarines work? Since there is no wasted electricity that can get to you if you are at the bottom of the ocean.


    In answer to the other question I am a Nuclear Engineer. I've designed facilities at Sellafield, refuelled reactors, written the safety justification for numerous parts of nuclear process plants and operated test systems.

  15. If Nuclear weapons don't cause any harm when simply at the ready, then why is it so dodgy to decommission them and also extremely expensive and dangerous?


    The facilities used to make them get massively contaminated in the purification and manufacturing stages. So they are very challenging to decommission, but the hardest thing to decommission is stuff at Sellafield, where reprocessing takes place. Far more active and far far far more of it. The missiles just need extreme caution in handling the plutonium or uranium so as to not get a criticality accident. This then needs disposed off and has been turned into reactor fuel and burnt up there instead.


    Its expensive as the kit being decommissioned wasn't designed to be taken apart, the modern buildings will be a lot faster then the 1950s legacy stuff. Its expensive as the government emptied the fund set aside for nuclear decommssioning in the 1990s to build Drax Coal Power station.

  16. Ok Rikko:


    Rikko, you know when the subs launch these trident missiles? Are they launched in the upright position and if so... how long are these trident missiles compared to the hull of the submarine.

    Plus! are they launched by compressed air until they fly out of the water?


    Upright position. They are about 10m tall and 3m wide, they take up most of the height of the submarine. They are launched in a compressed gas bubble, then when they reach the surface of the water the rocket engine fires.

  17. You appear to know a lot about this stuff, so I'd be interested to know a bit more.

    We are all Nuclear ready for armageddon, type of thing, with Nuclear missiles in silos ready for the ultimate strike.

    How long can these weapons hold Nuclear material that's decaying before they have to be took out and how do they manage to keep them inside silos without giving off radiation that kills anyone that's on maintenance?


    The UK has no silos, all our nuclear bombs are mounted on trident missiles and launched from submarines (whilst underwater) (you can watch a launch of one here

    ). At about 1 minute in you see the missile silos on the submarine. This was done to ensure 'second strike' capability and was arguably the thing that stopped any nuclear wars from starting. As the first thing you target in a nuclear attack is the other sides nuclear silos, but if the silo is hidden underwater and could be anywhere you can't hit it. Only the UK, Russia, USA and France have this capability.


    The materials that typically make one up are a fission trigger (either uranium 235 or plutonium 239) then a 'gas boost' which is provided by fusing deuterium, tritium or lithium 6. Out of these only uranium, plutonium and tritium are radioactive. Plutonium and uranium are long half life alpha emitters so as long as you dont eat them they are harmless. Alpha radiation cannot penetrate a single sheet of paper so the maintainers are safe. Tritium is a very very weak Beta emitter and the energy given off cannot penetrate human skin.


    The tritium needs replaced quite regularly as its only got a half life of about 12 years, the plutonium half life of 24,200 years so is good for ages and the uranium is good for about 700million years. I did some sums on the uranium and for 100kg of it you will get about 1 decay every 5 seconds. So in short the bombs aren't very active until they get set off. They just sit there fat dumb and happy until its detonated.


    Dangerous levels Radiation is only really given off by things with short half lifes that have strong gamma rays. Alpha and Beta are only dangerous if they get inside you. The biggest worries in the nuclear industry are Cs137 and Co60.

  18. Uranium is mined and mixed with a few ingredients into the HARD metal, it's then made into pellets which are only supposedly mildly radioactive.

    It's then put into long tubes and bundled together.



    Uranium compounds are mined, typically oxide form. This is extracted from rock and purified into form called 'yellow cake' or U3O8 in chemical composition. To convert it into modern fuel it is first turned into a gas by reacting it with flourine to get a compound known as 'hex' or UF6. It is then enriched to between 3 and 5% U235 (natural uranium is 0.7% u235) in a series of centrifuges or a huge gas diffusion plant. The uranium is then converted to uranium dioxide and turned into polo mint shaped pellets for use in a reactor.


    At this stage it is pretty benign as uranium has a very long half life its pretty stable. It will only do you harm if you decide to chow down on it as alpha radiation is pretty harmless unless it gets inside you.


    The first generation reactors used natural uranium metal fuel but these consisted of long bars covered in a magnesium alloy.


    They then start getting bombarded by neutrons and it split the atoms inside the heavy super steel hard uranium and it glows like the sun for years.

    Even after years of use, it's only supposedly used about 20% of it's fuel (atoms) and they take them out of the reactor and put them in SPENT fuel pools to cool down which takes years lol.


    The problem now is, they have went from mildly radioactive to ultra poisonous even though it's been used for 5 or 6 years supposedly fissioning.


    Uranium isnt a particularly hard metal, its just very dense. It doesn't glow. It looks just like a bog standard lump of steel and is about as harmful as a big old lump of steel. When a reactor is on there is a characteristic blue glow which is cherenkov radiation, but you can only see in a swimming pool type reactor. Its fully contained within the steel or concrete walls of power station reactors.


    Fuel typically stays in the reactor between 18 months and 5 years depending on its location in the reactor. The central sees more neutrons so is used up faster then those at the edge. When its taken out of the core there is still plenty of u235 left and a bit of plutonium and lots and lots of fission products. The most common fission products are things like caesium 137 and strontium 90 but basically every element lighter then uranium will be present in small amounts.


    It is the radioactive decay of these fission products that gives off the heat and the vast majority of the radiation. Its not poisonous, just very radioactive. If you were stand next to an unshielded fuel rod for about an hour you would recieve a dose of approx 4 Sieverts and would stand a 50% death from acute radiation sickness. If you survive that you would face a 20% chance of receiving cancer due to the radiation later in life.


    Now bear in mind, these pellets are hand held sized pellets, similar to what you see at the start of the Simpsons where Homer throws one out of his car, still glowing lol.


    Now they can hold spent fuel rods inside these pools for decades and decades and then they have to dump them somewhere inside flasks of lead and concrete and what not, yet they can also be re-cycled apparently. Hmmmmm, work that one out.



    The pellets are a lot smaller then you think, they are much closer to polo mint size. You are correct with the pools, the fuel is stored in 10m ish deep pools. Water is a very good radiation shield and excellent at removing the heat.


    The left over uranium and generated plutonium in spent fuel can be stripped out of the spent fuel and reused in new fuel. This is done by dissolving the spent fuel in nitric acid. Then using an organic solvent to extract the plutonium and uranium leaving behind a highly active liquid of fission products called 'HAL' and a plutonium and uranium mixture which can then turned into more fuel. This is done as it saves having to go through the highly expensive and energy intense uranium enrichment process.


    The HAL fission products are then concentrated in an evaporator and vitrified in a special kind of glass to immobilise it. This glass is then placed inside steel boxes and is currently stored in sellafield. There is work looking at building a large underground vault as the permanent place to dispose of these.


    The depleted ( supposedly highly poisonous) uranium can also be made into tips for artillery shells and tank shells, that I would assume can only be used by tank commanders dressed in nuclear fall out suits with big helmets.


    You won't be able to go anywhere near this stuff because if you do, you will fall to the ground frothing at the mouth and if you aren't wearing factor 26 million, your skin will be ruined.


    Depleted uranium is the left overs from the enrichment process I mentioned at the top. Its never been anywhere near a nuclear reactor and is harmless, unless of course its shot at you from tank cannon. Its used as its very dense and due to the extra weight will penetrate armour. Again as long as you don't decide to have a big old depleted uranium tank shell sandwich you will be fine.


    Granite is more harmful in terms of radiation then depleted uranium is. Your skin will be fine and the level of sunscreen you recommend is not required!


    This very same stuff sits in a big sealed container full of water and it glows, heating it up, yet the very same stuff, with a few drops of plutonium added, which is supposedly another metal can be made into discs and bullet shapes.


    You can then smash both pieces of metal together..(and remember we are talking about palm sized pieces of metal) and BANG, you can blow up a city and cause radiation fall out that lasts for hundreds and hundreds of years.


    They want us to believe in magic and it doesn't get much more magical than this.


    Now if people want to go on believing that we can blow this planet up with these things, then I don't have any problem with that. Yet when the time comes when the threat of nuclear war is on the cards, (which I believe it won't belong) I will be sat with my feet up smiling while many people will be trying to keep their own poo in.


    Its not the same stuff, its different. Depleted uranium is U238, the stuff that reacts in reactors is U235. Neither glows.


    The stuff in bombs is either very very highly enriched uranium (95%+ U235, compared with the 0.7% in natural uranium) or Plutonium 239. The amount you need to make a bomb is significantly more then you have as well. If you take 2 coke can sized lumps of this highly enriched uranium (660ml, which weighs approx 12kg) shape it into 2 hemispheres and bash them together nothing will happen other then a rather dull thud. You wont get any fissions or radiation other then the very very small amounts given off from the alpha decay.


    The aim in the 1950s was to create 1 megaton tnt equivalent bomb from 1 tonne of uranium/plutonium. The ones you mention are the designs from hiroshima and nagasaki, and that is a very simplified version of how they work. Your masses are well off the mark, think several hundred kgs, not hand sized lumps. The hardest part in making the bombs is stopping them blowing apart too early, as that is what they naturally want to do. To make them explode is actually ridiculously complicated, you can get a fizzle relatively easily where only part of the fuel is used but to get a full bomb you need a very precise timing and a great deal of tnt to keep the material together.


    The residual radiation from bombs isn't so bad as there is it very dilute, hence why there are still cities in japan rather then wastelands where hiroshima and nagasaki once stood. When the bomb goes off there is a huge pulse, but after its gone the radioactive matter is spread far and wide. The black rain that fell from the eye witness reports in hiroshima was the soot from the secondary fires with a great deal of active fission products trapped on them.


    As for a previous statement about the industry being secretive, all the information in this post is freely available online and accessible with google or in any number of books. If you genuinely have interest in this and want to know more I will happily point you towards free resources online that give more detail then you can shake a stick at.

  19. Wow, what a profoundly moronic post. Thousands of people's careers written off by the all 'knowing' wolfy. Each one of those scientists wolfy have contributed more to human knowledge than a million of you. I'd say that is a FACT.


    It's a great relief to me. I get paid to protect society from science and industry and now Wolfy has said its all faked I can just pop my feet up and let the good times roll!

  20. To the people blaming the rovers fans for their demise is mental. Change rovers for us and we'd have done the exact same thing if not more. THere are a lot of people panning them, but take a long hard look at what they faced before panning them for the kean out shite...


    Venkys really have stripped mined blackburn, they bought the club for £23million then sold phil jones for £20mil and reinvested bugger all of it. They make mike ashley look positively saintly and inspired in based on his performance during our relegation season, at least he had the balls to try and save it...

  • Create New...