Holtec acquires more retiring nuke plants

[OVERKILL]

Holtec, who is working on an SMR joint venture with Canadian company SNC-Lavalin (CANDU Energy) is in the process of acquiring more legacy nuclear sites, seemingly all single reactor at this point, for decommissioning, a process that they are also partnered with SNC on. One of the primary goals of the expedited decom projects is believed to be to garner community support for new builds of Holtec's SMR-160's. These SMR's, like others I've mentioned, have the ability to use low enriched fuel, which means they can potentially be run on BWR/PWR waste. In acquiring these sites, Holtec is simultaneously acquiring fuel.

Briefing on the joint venture can be found here:
http://www.world-nuclear-news.org/Articles/SNC-Lavalin-and-Holtec-team-up-on-SMR-development

In addition to the Oyster Creek plant I posted about in another thread, Holtec has worked with Entergy to purchase Pilgrim and Palisades after their closures. Details here:
http://www.world-nuclear-news.org/Articles/Holtec-takes-on-two-more-US-plants-for-decommissio


Will be interesting to follow this process, as they intend to greatly abbreviate the time required for decommissioning.

 

[Donald]

So these plants still have steam turbines in them? Are they also past useful life or can one generate steam a new way and power the turbines again? You have all the power grid attachments also.

 

[OVERKILL]

Originally Posted By: Donald
So these plants still have steam turbines in them? Are they also past useful life or can one generate steam a new way and power the turbines again? You have all the power grid attachments also.


Yes, they are fully active plants at the moment and still connected to the grid. Repowering them really isn't an option given the layout of a nuke vs a traditional boiler setup, but I think if there's to be potential redevelopment of the site, retaining the grid tie/transmission aspect may make sense. Be interesting to see what Holtec does in that respect.

 

[mk378]

The turbine in a fuel combustion power plant is built differently because a conventional boiler is designed to produce extremely hot and high pressure steam for best thermal efficiency of the plant (since fuel is their number one operating cost). Nuclear reactors operate at lower temperatures and correspondingly lower pressures for safety.

 

[john_pifer]

This is a little off topic, but I find myself trying to visualize the turbines in power plants.

So what size/dimensions are we talking about for the turbine of one of the reactors in a nuclear power plant? What about in a traditional coal-fired power station? Weight? Would it look similar to the bladed turbine section of a jet/gas turbine engine?

 

[OVERKILL]

Originally Posted By: john_pifer
This is a little off topic, but I find myself trying to visualize the turbines in power plants.

So what size/dimensions are we talking about for the turbine of one of the reactors in a nuclear power plant? What about in a traditional coal-fired power station? Weight? Would it look similar to the bladed turbine section of a jet/gas turbine engine?


They are massive. OPG has posted some pics recently from the Darlington Unit 2 refurbishment. Each unit is 878MW (may be higher post-refurbishment).

Some googled-grabbed OPG pics of the turbine hall:








Some shots of the caladria:



A shot of one of the caladria's at Bruce, which are similar:


An areal shot of the 3,512MW Darlington site:


And a simplified schematic of how a CANDU-based power plant operates:

 

[ssamaroo01]

These are ours at Indian Point. This is a typical design for a Westinghouse 4 Loop Pressurized Water Reactor. Our turbines spin at 1800 RPM instead of 3600 RPM at fossil plants and we have one high pressure turbine and 3 low pressure turbines.

 

[Shannow]

Originally Posted By: john_pifer
This is a little off topic, but I find myself trying to visualize the turbines in power plants.

So what size/dimensions are we talking about for the turbine of one of the reactors in a nuclear power plant? What about in a traditional coal-fired power station? Weight? Would it look similar to the bladed turbine section of a jet/gas turbine engine?


Not much like a jet engine.

I was a steam turbine engineer for a decade on coal units.

Steam was hotter and higher pressure than typical nukes. 1005F, and 2,600psi. That went into a High Pressure turbine, first row of blades only 2" high, and 7 blades stages. Dropped the pressure to 580psi, 600F...back to the boiler to be "reheated" to 1005F.

550psi 1005 F into the Intermediate Pressure turbine, which has a central steam inlet, and flows both ways through 7 stages dropping the pressure to 140psi, and again 600F give or take...then into two separate low pressure turbines, both with central inlets, and 6 stages (so four LP flows), last row of blades being 33.5" long, and discharging into the Condenser at -13.3psi (it's under vacuum for efficiency, and so the blades survive.

Here's an LP turbine I was reblading....that's 33.5" blades.


Machining the blade tips.


Those rotors are 50 tonnes give or take...all up with generator, 210 tonnes spinning at 3,000RPM, on 11 white metal bearings...700MW (although I DID crack 1,000,000hp in one test).

The Nukes are bigger all round, 44" last stage blades and bigger, and half speed turbines are common.

 

[Shannow]

Sorry, starteda reply 2 hours ago...got interrupted while OVERKILL was posting.

 

[Al]

Originally Posted By: john_pifer
This is a little off topic, but I find myself trying to visualize the turbines in power plants.

So what size/dimensions are we talking about for the turbine of one of the reactors in a nuclear power plant? What about in a traditional coal-fired power station? Weight? Would it look similar to the bladed turbine section of a jet/gas turbine engine?

As mentioned....turbines from nukes are much bigger. The Higher pressure unit from a nuke is not a whole lot bigger. But the Low pressure sections of the nuke are much bigger than on a coal fired plant. Also there are 3 low pressure on nukes and only 2..maybe even 1 on the coal fired.

 

[OVERKILL]

Great info from Shannow and Al as always

I found a few more pics from Darlington:





According to OPG, the LP stages are 470,000lbs, which is consistent with Shannow's number, roughly 213 metric tonnes, or 235 US tons.

 

[jhellwig]

I only worked on a crummy old 1950s coal former power plant turned cogen with a 20 MW unit run off 3 coal boilers. This makes me miss working on it though. Power generation is fun.

 

[john_pifer]

Really cool, guys. Thanks for the great information!

 

[Yah-Tah-Hey]

Originally Posted By: Donald
So these plants still have steam turbines in them? Are they also past useful life or can one generate steam a new way and power the turbines again? You have all the power grid attachments also.
Public Service of Colorado(PSCO) (now EXCEL) decommissioned Fort St. Vrain Generating Station in the late eighties because of the many problems of the reactor's helium cooling system. I was working at Craig Generating Station in northwestern Colorado and knew some of the employees there. I think it's fair to say they were very, very scared of that reactor. PSCO used what they could of the original plant and installed natural gas combustion turbine/generator sets. They utilized the waste heat of the combustion turbines to produce steam in steam generators to power the original steam turbine. Think Fort St. Vrain is making about 900+ megawatts.

 

[Yah-Tah-Hey]

Thanks for the memories guys. I remember the high pressure/intermediate pressure turbine top half weighed 38,000 lbs. And this is a relatively small 420 MW unit. Also recall that the generator rotor weighed sixty tons. Does that sound correct? Twenty+ years into retirement and have to stop and think what kind of turbine/generators and steam generators we had there. GE and Babcock & Wilcox? The gantry cranes for all three units had 30 ton and 80 ton hooks.

 

[Yah-Tah-Hey]

OVERKILL: What is that shaft with the spur and helical gears? Also what is that ratchet looking gear? Wonderful,very clear photos. Your the man.

 

[Shannow]

Yep, those are typical numbers.

I've gone for other jobs in other industries, been made offers, but there's nothing can compare to power stations...maybe a nuke sub or aircraft carrier, but that's never going to happen.

 

[Yah-Tah-Hey]

Originally Posted By: Shannow
Yep, those are typical numbers.

I've gone for other jobs in other industries, been made offers, but there's nothing can compare to power stations...maybe a nuke sub or aircraft carrier, but that's never going to happen.
Lots of overtime with Murphy showing up on the last day of the work week twenty minutes before beer thirty. And the suits who couldn't find the front door of the powerhouse wanting to know every hour when the unit was going to be given back to operations.It was a good paying job with good benefits and no worry about the place closing. We were one of the first REA funded generating stations that filed for bankruptcy and things got a little dicey for about two months. The company that took over the assets was just as good as the original company was FUBAR. The problem being trying to operate a 1260 MW plant with a 100MW mentality. Your turbine inlet temps and pressurs are almost identical to out GE/B&W BTGs. Always look for your posts.

 

[OVERKILL]

Originally Posted By: Yah-Tah-Hey
OVERKILL: What is that shaft with the spur and helical gears? Also what is that ratchet looking gear? Wonderful,very clear photos. Your the man.


I cannot take any credit for the photos, they are provided by Ontario Power Generation as part of their coverage of their Darlington Refurbishment project.

I have no idea what that shaft and gear assembly belongs to, perhaps some form of lift?

 

[john_pifer]

Originally Posted By: Yah-Tah-Hey
OVERKILL: What is that shaft with the spur and helical gears? Also what is that ratchet looking gear? Wonderful,very clear photos. Your the man.


Yes! Thanks so much for all the awesome photos, guys!

I voraciously consume any and all information about power generation, transmission, distribution, etc. Really fascinating.

Any of you power plant guys ever been involved in any HVDC power transmission projects? Lots of interesting reading I've done on that. I can get lost in reading about that stuff for hours.