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PostPosted: Aug 10, 2014 11:08 am 
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There's a reason why they're switching away from the organic material to the steel liner that everyone else uses. It has much better high temp and rad resistance.

Inconels are ASME certified. 718 is very strong so is often used to bolt down pressure vessel heads. Failure of the bolt constitutes an ASME BPV boundary failure.

Ordinary concretes are ASME div. III certified. DUCTAL probably isn't though.


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PostPosted: Aug 14, 2014 12:34 am 
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http://www.world-nuclear.org/info/Nucle ... er-Plants/
Pressure vessel manufacturing capacity is limited. Indians need Japan OK to import French EPR.(not approved so far). Fortunately, the Russians have their own facilities for their VVER. Still, the supply of pressure vessel is a critical action in building a VVER. The Canadian logic remains relevant today.
The alternative is SMR, which is being seriously pursued but has not reached the stage of safety approval yet.
Regarding Calandria design, I think that it should be frozen @ 400 tubes at most.


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PostPosted: Aug 14, 2014 1:30 am 
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jagdish wrote:
http://www.world-nuclear.org/info/Nuclear-Fuel-Cycle/Power-Reactors/Heavy-Manufacturing-of-Power-Plants/
Pressure vessel manufacturing capacity is limited.


If so, then that is another reason to like the superalloy vessels. They have about 1/3 the weight, so for a given yearly pressure vessel tonnage capacity, you can make 3x as many vessels.


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PostPosted: Aug 15, 2014 1:24 am 
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Pressure vessels of a light, strong alloy will be required to be of same dimensions, even if lighter. The forging capacity of same plants might increase but not in inverse proportion to mass.
One cannot find fault with using existing manufacturing capacity or the reactors in use. However future nuclear capacity, if fast build up is required, may take less cost and effort by using lower pressures (no water or gas in the core) or smaller pressure tubes. Building capacity of SMR reactor vessels may also be easier to build up.


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PostPosted: Aug 15, 2014 3:34 pm 
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jagdish wrote:
Pressure vessels of a light, strong alloy will be required to be of same dimensions, even if lighter. The forging capacity of same plants might increase but not in inverse proportion to mass.


Do you have a reference for this assertion? Forging work is extremely dependent on forging weight and thickness. It may well be more than proportional to thickness. At the limit, consider stamped out material, like cookingware. This is stamped out in a single "BLAM". Less than 1 second. Compare to endlessly hammering a thick forging. We'd need a forging expert to comment.

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One cannot find fault with using existing manufacturing capacity or the reactors in use. However future nuclear capacity, if fast build up is required, may take less cost and effort by using lower pressures (no water or gas in the core) or smaller pressure tubes. Building capacity of SMR reactor vessels may also be easier to build up.


France used the highest pressure type reactor available, the PWR, and went from 20% to 75% nuclear in under 15 years. Doesn't seem like a limitation if the drive is there.

We can never use just low pressures because the power cycle is more efficient the higher the pressure. So you need thick turbine casings, and forgings reduce the number of welds compared to a welded structure.

The reactor vessel of MSRs isn't exactly thin either. This is due to thermal creep necessitating low design stresses. An LWR might operate at 150 MPa hoop stress. To get similar safety margins with MSR vessels you have to think about 25 MPa and even less if you plan to make the vessel last as long as the LWR. So its at least 6x thicker than the low pressure leads you to believe.


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PostPosted: Aug 15, 2014 4:29 pm 
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France managed that by using relatively small units (not the 1600MWe monsters we have now) and with a far greater quantity of heavy engineering capacity than we have available in the west at the present time.

It seems unlikely that such a rate would be obtainable from a standing start today.

(What about wire winding a pressure vessel?)


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PostPosted: Aug 15, 2014 4:52 pm 
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E Ireland wrote:
France managed that by using relatively small units (not the 1600MWe monsters we have now)


The size and weight does not scale so strongly. A 4 loop 1600 MWe vessel is only slightly bigger and heavier than a 3 loop 900 MWe vessel.

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and with a far greater quantity of heavy engineering capacity than we have available in the west at the present time.


I hear this a lot and have never bought into it. Have you ever been at any steel plant with a big hot roller steel plate production? There is one near my home, which is in the west, if you will. That plant churns out 225 mm steel plates like its hot butter. Its just scary. They make millions of tonnes of high quality steel each year.



Quote:
(What about wire winding a pressure vessel?)


It should work, but what is to be gained? The wire has to be ultra high strength to gain much over a superalloy forged vessel. Such wire isn't very ductile and we don't know its nuclear performance.

Any sort of loss of tensioning (by loss of geometry for example) in this application can cause a failure mode. Its kind of like prestressed posttensioned concrete except the wire has more possibilities for getting loose.


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PostPosted: Aug 15, 2014 7:28 pm 
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There are very few facilities in the west that can turn out forgings of the required size and scale.
This is one of the reasons that nuclear build out of BWRs would prove so problematic.

Turning out plates is easy compared to forging - otherwise we could just cast pressure vessels in one piece in a couple of hours and be turning them out by the dozen.

It would take years to build up large quantities of the very powerful forges required to turn out large number of pressure vessels.
Most facilities I see have a capacity of a few units worth of forgings a year - and would take years to build at the cost of billions of dollars.

This is one of the reasons I have given up on LWRs in favour of CANDU/SGHWR type jobs.


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PostPosted: Aug 16, 2014 3:12 am 
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E Ireland wrote:
There are very few facilities in the west that can turn out forgings of the required size and scale.
This is one of the reasons that nuclear build out of BWRs would prove so problematic.


There are few facilities because the west is anti-nuclear, by and large. Why would a commercial enterprise invest in it if it isn't wanted by society? Heck, a weapons manufacturing facility is wanted a lot more than nuclear power plants, in the west. It is not about technology, it is about business environment.

Quote:
Turning out plates is easy compared to forging - otherwise we could just cast pressure vessels in one piece in a couple of hours and be turning them out by the dozen.


Hot rolling plates does not involve liquid casting. That happens before that. The hot rolling is a solid state, elevated temperature process. Plastic deformation by mechanical force - similar to forging. Massive force is required to squeeze the 225 mm plates. As discussed, liquid casting pressure vessels has many issues. Forging is more robust and tough.

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It would take years to build up large quantities of the very powerful forges required to turn out large number of pressure vessels.


So it doesn't take years to get the specialized know how and manufacturing involved with CANDU pressure boundaries? Zirconium is a rare metal and few people have experience working with it. Then there is the complex network of manifolds and headers, combined with a complicated refuelling machine. All highly specialized equipment. Cold rolled joints from zirconium alloy into stainless steel headers... all very specialized. Oh, and I forgot to tell, the massive massive steam generator forgings of CANDUs. And the massive turbine casings. And the pressurizer. And the core makeup tanks. And the feedwater heater shells. And... etc.

Quote:
Most facilities I see have a capacity of a few units worth of forgings a year - and would take years to build at the cost of billions of dollars.


An interesting article on forgings:

http://www.world-nuclear.org/info/Nucle ... er-Plants/

The European and American forges have about 1/3 the forging weight capacity as the big Japan Steel Works forge. So, switch to Inconel 718 and you reduce forging weight to 1/3 and you can make the same big vessels at 1/3 the weight in European and American forges.

Even if you are right about forgings, then it makes no sense that big nuclear players like GE and Westinghouse increasingly use forgings rather than weldings. If this were truely a big headache, they would go back to welded plate. And we could do that easily, especially with superalloy that is much thinner so easier to weld.


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PostPosted: Aug 16, 2014 5:07 am 
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What do the Russians, the world's major suppliers of reactors, use?


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PostPosted: Aug 16, 2014 6:06 am 
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jagdish wrote:
What do the Russians, the world's major suppliers of reactors, use?


PWRs. Fuel channel reactors (RBMKs) are on the way out. Russians are doing quite well with their rather deviating PWR design, the VVER series.

The ref I gave says a company called OMZ Izhora has the biggest or single biggest global pressure vessel manufacturing capability. In terms of press weight and max forging weight. Very similar to the massive Japan Steel Works plant in fact.


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PostPosted: Aug 16, 2014 6:59 am 
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Cyril R wrote:
E Ireland wrote:
There are very few facilities in the west that can turn out forgings of the required size and scale.
This is one of the reasons that nuclear build out of BWRs would prove so problematic.


There are few facilities because the west is anti-nuclear, by and large. Why would a commercial enterprise invest in it if it isn't wanted by society? Heck, a weapons manufacturing facility is wanted a lot more than nuclear power plants, in the west. It is not about technology, it is about business environment.

That is the environment we are in - if the west becomes pro nuclear it won't cause giant 600t forging presses to appear out of nowhere.

Cyril R wrote:
Quote:
Turning out plates is easy compared to forging - otherwise we could just cast pressure vessels in one piece in a couple of hours and be turning them out by the dozen.


Hot rolling plates does not involve liquid casting. That happens before that. The hot rolling is a solid state, elevated temperature process. Plastic deformation by mechanical force - similar to forging. Massive force is required to squeeze the 225 mm plates. As discussed, liquid casting pressure vessels has many issues. Forging is more robust and tough.

Indeed, but hot rolled plates do not require forging 600t pieces of metal in one go - it is a continuous process not a single piece batch one.
The actual force required to hot roll the continuous strip is not that large compared to that required to forge a reactor pressure vessel section.

Cyril R wrote:
Quote:
It would take years to build up large quantities of the very powerful forges required to turn out large number of pressure vessels.

So it doesn't take years to get the specialized know how and manufacturing involved with CANDU pressure boundaries? Zirconium is a rare metal and few people have experience working with it. Then there is the complex network of manifolds and headers, combined with a complicated refuelling machine. All highly specialized equipment. Cold rolled joints from zirconium alloy into stainless steel headers... all very specialized.

None of these things require billion dollar presses that simply don't exist any more?
It does not take that much force to forge a zirconium tube, indeed I believe you can roll them rather than use a forge.

Manifolds and so on might be complex but they, again, don't require huge machinery that is simply not in existence.
Rolling zirconium is not that different to simply rolling similar sized aluminium pipes which happen every day.
Cyril R wrote:
Oh, and I forgot to tell, the massive massive steam generator forgings of CANDUs. And the massive turbine casings. And the pressurizer. And the core makeup tanks. And the feedwater heater shells. And... etc.

All of which are present in PWRs.
And the tonnage of forgings is irrelevant - the problem is that we simply can't make large enough forgings in the required quantities.
The steam generator forgings are far smaller than the pressure vessel forgings on a PWR - ditto turbine casings.
Cyril R wrote:
http://www.world-nuclear.org/info/Nucle ... er-Plants/

The European and American forges have about 1/3 the forging weight capacity as the big Japan Steel Works forge. So, switch to Inconel 718 and you reduce forging weight to 1/3 and you can make the same big vessels at 1/3 the weight in European and American forges.

Even if you are right about forgings, then it makes no sense that big nuclear players like GE and Westinghouse increasingly use forgings rather than weldings. If this were truely a big headache, they would go back to welded plate. And we could do that easily, especially with superalloy that is much thinner so easier to weld.

They don't go back to welding because there is absolutely no shortage of forgings - because there is no nuclear renaissance.
If you stick with heavy forgings you are stuck with basically the current rate of reactor construction.
Which is going to have difficulty doing more than simply keeping up with the rate of reactor shutdown.

I can't find anything to suggest that 200t+ forgings of Inconel have ever actually been made.


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PostPosted: Aug 16, 2014 7:53 am 
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Quote:
That is the environment we are in - if the west becomes pro nuclear it won't cause giant 600t forging presses to appear out of nowhere.


We are just going to have to agree to disagree on this one Ed. You think that forging presses are the bottleneck to PWR/BWRs in places like Europe. My interpretation is that it is the anti nuclear political, social, regulatory, and business environment that we in the west have created. France didn't have the required forging capacity before its nuclear renaissance. They managed just fine because the political, regulatory, and business environment was integrated to efficiently and effectively switch over to nuclear power.

There is nothing particularly technically difficult regarding 600t forging presses. Not in today's world where we have single steel plants churning out 225 mm thick steel and thinning that out to just a few mm at a rate of millions of tonnes per year.

Quote:
Indeed, but hot rolled plates do not require forging 600t pieces of metal in one go - it is a continuous process not a single piece batch one.
The actual force required to hot roll the continuous strip is not that large compared to that required to forge a reactor pressure vessel section.


About 12000 kWe (2x2x3000 kWe) of electric motors, are continually needed to operate the facility I was referring to. Maybe you think 12000 kWe is not much? Steel, even when hot, is not at all like butter. Yet these hot rollers make it churn like butter. When the thinned out plate is leaving the roller section, it is being rolled up at the speed of a speeding car. Its massive. It makes a forge just look like an ordinary big hammer. Gravity does all the work, you don't need that big input powers.

Quote:
Manifolds and so on might be complex but they, again, don't require huge machinery that is simply not in existence.


So you trade away the huge machinery that is not in existence, for a great increase in nuclear quality welder army that is not in existence. CANDUs have never proven to be built quickly or many at a time. Look at the difficulty pro nuclear countries like India are having in actually building a few of these tiny CANDU derivative reactors.

Again I believe the reason there is no capacity and the slow pace of things is because of the entrenched political, business and regulatory situation. There is no demand for large nuclear plants so why would a commercial forger work to increase capacity?

Lets look again at the numbers Ed.

http://www.world-nuclear.org/info/Nucle ... er-Plants/

Japan steel works: doubled capacity from 2009 to 2012.

MHI: ditto.

Shanhai: ditto

Russia OMZ: ditto.

All doubled capacity in 3 years.

The difference is all these countries - Japan, China, Russia - have a pro nuclear political, regulatory and business environment and have not adopted all (but still some) of the debillitating quality control and regulatory system installed in Europe and North America.


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PostPosted: Aug 16, 2014 8:06 am 
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Quote:
I can't find anything to suggest that 200t+ forgings of Inconel have ever actually been made.


Actually we don't need such heavy forgings. I calculate 20 to 25 tonnes for the bottom section and about 50 tonnes for the first ring (6 meters tall). Everything above the first ring can be welded plate if necessary.

I have various quotes from Chinese fabricators on 15-20 tonnes In718 forgings, these are almost mass produced (standard sizes, one supplier can deliver up to 10 a month or even more upon steady contract, or so they claim). No positive response yet on 50 tonnes, that seems to be pushing it. Will ask a bit more for suppliers in the Jiangsu area they are pretty good at this sort of thing.


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PostPosted: Aug 16, 2014 8:09 am 
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Wow 5000 posts, what a massive showoff this Cyril R. Can't shut his mouth for a minute.


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