Nuclear Ship VS Nuclear Power plant construction

needadditionalinformation
16th March 2011, 02:28
With the horrible mess in Japan with those Nuclear Reactors, I was wondering if shore-side nuclear power plant designers could learn something from the construction of nuclear powered ships.

Now, if you care to reply, please don't be too hasty, I'm not a nuclear engineer, but I'm wondering if land based nuclear power plant designers could take lessons, so to speak or directly, from Naval Architects in order to build housing for those reactors that would be more robust than those Japanese (Daiichi?) nuclear power plants.

I would tend to believe that these ships encounter movement and forces far in excess of what that earth quake dished out. While a ship's hull (ULCC size?) wouldn't have to be the exact form, maybe it could be a place to start thinking about it.

It would seem strange to build a (large) ship's hull structure just to house a power plant, albeit one so close to the water, and there would be the issue of mooring it sufficiently so that it didn't float ashore with everything else, but given what the SS Savannah's hull was built to withstand in the event of a collision (to protect the reactor), and the protective benefit that could provide, and the nightmarish consequences of having 3 or more reactors meltdown, as may yet happen, the unprecidented cost and trouble of such construction might be well worth it.

Finally, one of my WWII era textbooks on Marine Engineering noted that "many lives have been saved because there are no yellow streaks in black gangs". We know not one Engineer from the Titanic survived, and eviently it's working the same way ashore in Japan right now. God Bless those men who are trying to contain the disaster, but it dosen't look like it's going to be pleasant for them.

lazyjohn
17th March 2011, 12:18
I hate to think that anybody would wan't the Japanese problem compounded by sinking the reactors to the sea bed as well.

needadditionalinformation
19th March 2011, 19:38
Well, I guess I didn't make it clear. I didn't intend the structure to actually be afloat, but ashore, just built alot better than those buildings were. The whole mess over there has just been getting worse by the day according to the news, and the Nuclear Engineers CNN and such are consulting on this are saying they don't know how bad this situation is, and that even the Japanese won't for some time.

I therefore do not subscribe to the view that the buildings and their earthquake resistance was fine, and the lack of Tsunami resistance in the design was the problem. Since the experts don't & won't know all the consequences, I think it would be too hasty a generalization to say that, and I still believe that a substantially stronger building to house those reactors may have helped.

And there are atleast part of those plants the Japanese do wish they could sink right now, albeit in a body of water the contamination could be controlled in.

I don't know what they're saying in the coverage in the U.K., but over here, the networks are saying that the Japanese fear the spent fuel pools are so cracked that they can't keep cooling water in them if they can even get water to them. Given the flow of events, I'd think it'll be some time, if ever, whether we know if the hydrogen explosions or the earthquake caused the cracking, and if both, how much of each.

Nick Balls
19th March 2011, 20:01
Hindsight is a wonderful thing. I would imagine that they are already looking at potential flaws in design with UK plants........ I was rather amused reading a local paper that said 'off course we don't have tsunami' when talking about sizewell nuclear power station here on England's east coast..........well OK not tsunami but we do have an increasing number of storm surges some of which raise sea level by more than 2 Mts........don't sound a lot but the destructive force of such events historically have wiped out whole towns very swiftly in times gone by. The town of Dunwich was wiped out (finally) in the course of a single night.

steamer659
28th March 2011, 05:14
Gents,
Knowing just enough about these plants to be dangerous, I must comment on the fact that the latest horrid mess was due to the fact that the emergency generators were wiped out in the tsunami and there wasn't any power to run the coolant pumps- remember that dumping sea water into the containment vessel probably caused a steam explosion of sorts....Chernobyl- although a different type of reactor entirely was also caused by a loss of coolant flow- only that time they were testing the ability of the generator (1000 MW) to supply electricity to run the coolant pumps during a coast down after a turbine trip- A planned excursion!

Emergency generators on most merchant vessels are located at or ABOVE the freeboard deck, maybe our shoreside counterparts would benefit from elevating and class a containing these most important emergency power supplies....

LaFlamme
28th March 2011, 06:59
Bill,
Your suggestion has a lot of common sense appeal to it. Unfortunately I don't believe it would be practical to scale up a maritime design to the size of the land reactors. Each one of those six Japanese reactors, for example, is probably immensely more powerful, and more dangerous, than any nuclear power plant ever put to sea. And, it still leaves us with the insurmountable problem of nuclear waste. What can we do with that stuff? How many thousands of years must we care for it, and how many earthquakes and other calamities will it have to be subjected to during those thousands of years?
Andre

lazyjohn
28th March 2011, 10:32
Hindsight is a wonderful thing. I would imagine that they are already looking at potential flaws in design with UK plants........ I was rather amused reading a local paper that said 'off course we don't have tsunami' when talking about sizewell nuclear power station here on England's east coast..........well OK not tsunami but we do have an increasing number of storm surges some of which raise sea level by more than 2 Mts........don't sound a lot but the destructive force of such events historically have wiped out whole towns very swiftly in times gone by. The town of Dunwich was wiped out (finally) in the course of a single night.

Regret to report that tsunami has happened in UK.

About 1600,s the Bristol Channel area was inundated by what was reported as a storm/high tide. However, tide was only blamed because they had never heard of tsnunami. Latest research indicates wave was caused by undersea landslide south of Ireland (site can still be seen on 'Google Earth'.

Bank of the Bristol channel is the site of at least one nuclear power plant and recent events indicate more may be built soon.

PS. I am a nuclear power supporter.

steamer659
3rd April 2011, 16:34
I too, John, are a supporter of Nuclear Power... While the latest set of events in Japan are unfortunate, they still do not diminish the fact that Nuclear Power is cleaner, cheaper and safer overall than any of the alternatives...

Here in the US, the NRC probably regulates these important parts of out infrastucture to the point of over-regulation: We need to build more plants, albeit safer...

Philthechill
3rd April 2011, 22:28
I believe the foul-up, in Japan, was caused by the tsunmai carrying-away the fuel-tanks for the diesels net result, no fuel, no power.

This is, of course, the "X" factor which always, but always, causes the problem which brings the whole house-of-cards tumbling down.

This on-going disaster, in Japan, has been caused by one of these "X" factor problems which just can't be foreseen! Yes you can "dial-in" just about every possible scenario you can think of and, who knows, someone may even have said, "Right! Just supposing we get a monster sub-sea earthquake, which creates a massive tidal-wave so big it engulfs the power-station, (which has already shut-down because of the massive earth-quake), and carries-away the emergency generator fuel-tanks which result in the cooling-system shutting-down, ergo no coolig-water to remove the excess reactor heat?"

The design-team would have looked, (pityling!), at this guy, (if he/she ever existed!), and, after checking if he/she had a "drink-problem", would then have sent them to a nursing-home to recover from his, (obviously), over-imaginative "over-the-top" suggestion to be the result of overwork!

In short, I just think it was an extremely unfortunate accident of the type that just cannot be foreseen. Who, for example, would have/could have thought, when Concorde was being designed, "Right! Just supposing Concorde is taking-off and one of its wheels picks-up a piece of debris, which fell-off another aircraft during its take-off run. Then this piece of debris gets hurled-up, at huge speed, pierces the outer skin of the wing and then pierces one of the fuel-tanks?" Or that other dreadful "debris-caused-tragedy", the space-shuttle "Challenger" which, tragically, blew-up on its re-entry to Earth's atmosphere. The cause? A lump of fuel-tank foam-cladding which fell-off during "lift-off", pierced the leading-edge of the port wing and casused massive wing-overheating and susequent disintegration of the entir Shuttle


Hind-sight is a wonderful thing, (which we all possess in huge quantities!), and frequently good things can come from it but we still have to look at things sensibly rather than condemn something, (such as these nuclear power-plants), out-of-hand and say, "What idiot DID that? We must NEVER build nuclear power-stations, (or whatever), again!" Salaams, Phil(Hippy)

P.S. Let's not forget one very important point. The monster earthquake DID NOT cause any problems at all! It was the subsequent tidal-wave.

John Jarman
13th April 2011, 10:18
Having worked in the power industry, although not on nuclear plants, it is right that sea-going systems would have to be massively increased in size, to be viable. Most plants around the world, except the UK, are pressurised water systems (PWR) or and advancement of that - BWR. The UK uses the AGR system (Advanced Gas-cooled Reactor), using CO2 as the coolant - again, a development of the older Magnox reactor.
In my opinion ( and the government of the time), these are safer than the PWRs, so I don't think we would be at risk from "natural" occurrences so easily.
Unfortunately, our reactors have had more operational problems that cause them to run at reduced output, so, while the safety benefit is there, the better efficiency of the AGR has not been realised.

Regards,

JJ.

LaFlamme
14th April 2011, 06:31
I recently read about a U.S. company, TerraPower, working on a new type of nuclear reactor: it would reuse waste uranium that has been produced by nuclear plants now in operation. Bill Gates, from Microsoft fame, is an investor in that project. By what I understand about it, this type of reactor would be much smaller, probably entirely installed underground, and would be much simpler to operate. It is only a design at the moment, but they are looking for a country that would let them build a prototype. Good luck with that!

I don't want to be naive about it, but it might be a safer way to use nuclear energy. I am not afraid of nuclear power per se, but we have not yet figured out a way to deal with nuclear waste; and that will remain a major stumbling block.

Even though I am a strong advocate of energy conservation, clean energy, etc, there is little chance that we will stop, or even slow, the warming of the earth unless we also use nuclear power, along with all the other renewable sources that we are developing. I prefer nuclear to coal!

And here in the U.S., where I live, half of our politicians don't even believe in climate change, so they are not ready to make the decisions to invest in clean energy. So... we are slowly going down with our mother ship!
Andre

Blackal
14th April 2011, 19:27
Having worked in the power industry, although not on nuclear plants, it is right that sea-going systems would have to be massively increased in size, to be viable. Most plants around the world, except the UK, are pressurised water systems (PWR) or and advancement of that - BWR. The UK uses the AGR system (Advanced Gas-cooled Reactor), using CO2 as the coolant - again, a development of the older Magnox reactor.
In my opinion ( and the government of the time), these are safer than the PWRs, so I don't think we would be at risk from "natural" occurrences so easily.
Unfortunately, our reactors have had more operational problems that cause them to run at reduced output, so, while the safety benefit is there, the better efficiency of the AGR has not been realised.

Regards,

JJ.

The PWR is an advancement of the BWR.

The BWR puts steam, which has been created in the reactor pressure vessel - into the turbines.

The PWR has one additional barrier, in that the primary coolant (which circulates through the reactor pressure vessel) does not flash off to steam - it merely heats the water in the steam generators indirectly - to produce the steam for the turbines.

PWRs have a very high power density, which is not really required for shore-based reactors, and if something goes wrong (full-bore steam leak, primary coolant leak etc) - things happen extremely quickly. Operators must react very quickly to failures, and carry out regular practice drills.

Al

John Jarman
15th April 2011, 13:46
The PWR is an advancement of the BWR.

The BWR puts steam, which has been created in the reactor pressure vessel - into the turbines.

The PWR has one additional barrier, in that the primary coolant (which circulates through the reactor pressure vessel) does not flash off to steam - it merely heats the water in the steam generators indirectly - to produce the steam for the turbines.

PWRs have a very high power density, which is not really required for shore-based reactors, and if something goes wrong (full-bore steam leak, primary coolant leak etc) - things happen extremely quickly. Operators must react very quickly to failures, and carry out regular practice drills.

Al

As I stated before, the BWR and subsequently the ABWR (advanced), came after the PWR. At least, that was the information used in the
60s, when I attended many courses while working within the CEGB. If you have direct operating experience of either, I will bow to your superior knowledge.
However, PWRs were still the prime choice for submarines, being more compact and powerful for their size, than the BWR and some of the safety characteristics were uncertain at the time.
As an aside to Phil's post, when the CEGB had to decide on the Magnox replacements, one of the main priorities was to use existing boiler/turbo/ alternator unit designs that were in production for the latest fossil fired stations. These were generally the 500 - 666MW units installed at places like Ferrybridge "C" (the first 500MW unit) and ultimately, Drax. Therefore, reactor steam conditions needed to match these large turbines. With AGRs, this was accomplished.
Regards,

JJ.

Blackal
15th April 2011, 19:08
John,

Sorry - I have my 'propulsion' head firmly on - when I assert that the PWR was a development of the BWR. The BWR preceded the PWR if I'm not mistaken, and Admiral Rickover took the decision to go with the PWR for the US navy.

For propulsion - there is little doubt that was the correct decision, and since then, the original Westinghouse design has not been radically changed in principle.

Al

lazyjohn
15th April 2011, 19:54
I too, John, are a supporter of Nuclear Power... While the latest set of events in Japan are unfortunate, they still do not diminish the fact that Nuclear Power is cleaner, cheaper and safer overall than any of the alternatives...

Here in the US, the NRC probably regulates these important parts of out infrastucture to the point of over-regulation: We need to build more plants, albeit safer...

Please remember the UK is about the size of Rhode Island and has a population in excess of 60 million.

Where would everybody be evacuated too in the event of a Chernobyl size contamination episode.

We can't afford even one really major bad event.

Would USVI take us all in?

I still support nuclear power generation but have many valid objections as well.

John Jarman
15th April 2011, 21:15
John,

Sorry - I have my 'propulsion' head firmly on - when I assert that the PWR was a development of the BWR. The BWR preceded the PWR if I'm not mistaken, and Admiral Rickover took the decision to go with the PWR for the US navy.

For propulsion - there is little doubt that was the correct decision, and since then, the original Westinghouse design has not been radically changed in principle.

Al

Sorry, still not convinced by your reply. The information I have (from 1965 CEGB course literature) indicates that '....perceived improved thermal efficiency by taking the heat-exchanger, exterior on the PWR, and including it within the reactor pressure vessel and calling it BWR.....' Written as a simplification for the benefit of us fossil firers and us not being involved with the nukes!! Seems a logical progression to me but if you can provide a timeline for the two, that proves your point, it will provide definite information for all "trivia" enthusiasts.
It could be the other way of course - that they had BWRs and thought - let's take the heat exchanging out of the reactor and use seperate heat transfer vessels and call them PWRs! We could then do away with shielding the turbine, etc. I think the timeline was so close in the early 1950s as to make very little difference anyway. For propulsion purposes the PWR was the obvious choice.
Regards,

JJ.

Blackal
15th April 2011, 21:38
Mmmm....... Looking back - it appears that the two types were probably developed in parallel. With the race on - all avenues were being pursued (including the CANDU reactor). What is certain, is that both types of reactor were 'in the race' when Rickover steered US Navy development down the PWR route.

The additional perceived benefit of the PWR (in propulsion applications) - (and up until recently - was still something that concerned the industry) was boiling within the core, which could cause parallel channel instability - which in turn could cause a complete reversal of flow in some coolant channels. The reversal of flow meant that affected fuel rods could overheat and possibly rupture - releasing fission products into the circuit.

It is now accepted (at least within the UK-produced PWRs) that some amount of boiling can be accepted within the core.

Oh - post 14 - I seem to have changed words from 'advancement' to 'development'. For propulsion - 'advancement' is the correct choice of words.

Al

John Jarman
16th April 2011, 14:43
Al. Parallel developement - I was thinking the same.

Regards

JJ.