OT: We Pick Things Up And Put Them Down

CTMike

During our refueling outages, we pick up a lot of very heavy things and then put them down. This outage we are replacing our main generator rotor as it is nearing its end of life. It doesn’t look it, but this weighs just over 200 tons (401,100 lbs to be exact). The fans you see on either end of the shaft are used to circulate hydrogen which is used to remove heat (hydrogen has a pretty good specific heat capacity). Not nearly as high as water but we can’t run water through the generator for obvious reasons. 

kl8ton

Thanks for sharing!  Looks like a very clean place! Where does the shaft go at the end of its life?  Is it rebuildable or does it head to the scrapyard?

alaskanassasin

Hard to see the suction cups in your photo… seriously though that is awesome.

CTMike

kl8ton said:

Thanks for sharing!  Looks like a very clean place! Where does the shaft go at the end of its life?  Is it rebuildable or does it head to the scrapyard?

We are actually storing the old one on-site for awhile until reliability of the new one is proven. After that I don’t know what it’s final disposition will be. 

fishlessman

thats a bigun.  i like how everyone needs to wear a safety hat, you know....incase that strapping fails. whats the rating on that crane

GrateEggspectations

@CTMike I sure hope the storage closet is spacious. 

CTMike

fishlessman said:

thats a bigun.  i like how everyone needs to wear a safety hat, you know....incase that strapping fails. whats the rating on that crane

The crane is rated for 250 tons. 

Langner91

I'd love to see the bearings that are at each end of that shaft!  My retirement is probably directly tied to them.

CTMike

Arkansas Nuclear One had a fatal accident occur back in 2013 when the temporary rigging gantry failed due to some faulty engineering calculations. 525 tons falling about 65 feet does a lot of damage:

http://cdn.allthingsnuclear.org/wp-content/uploads/2015/02/FS-181-PDF-File-with-links.pdf

dbCooper

@CTMike

Thanks for sharing, very cool.

nolaegghead

"Bill, where are the zerk fittings?  You forgot?!  How in the hell are we gonna lube this mother?"

Cool Mike....I love engineering.

RyanStl

alaskanassasin said:

Hard to see the suction cups in your photo… seriously though that is awesome.

Yeah, I thought this going to be a suction cup thread too. This is cool though.

nolaegghead

https://youtu.be/jNklMSF_fsY

SamIAm2

@CTMike - can you tell us about those straps? Very cool!

CTMike

The rigging slings are made of some fiber (Aramid maybe) made by a company called SlingMax. Much lighter than steel cable slings for the same load rating. 

Ozzie_Isaac

Very cool!  Having previously worked with heavy machinery, and being near one rigging/hoist failure, this is incredibly interesting.

fishlessman said:

thats a bigun.  i like how everyone needs to wear a safety hat, you know....incase that strapping fails. whats the rating on that crane

When I worked with explosives, we used to joke about our safety glasses.  Assumed they were used to capture DNA for identification purposes if there was a mishap.

caliking

CTMike said:

kl8ton said:

Thanks for sharing!  Looks like a very clean place! Where does the shaft go at the end of its life?  Is it rebuildable or does it head to the scrapyard?

We are actually storing the old one on-site for awhile until reliability of the new one is proven. After that I don’t know what it’s final disposition will be. 

When the time comes, give @nolaegghead a call...

Corv

How well is that thing balanced?

RyanStl

Is that 5+ engineers standing there watching while 1 or 2 people do all the work?

fishlessman

RyanStl said:

Is that 5+ engineers standing there watching while 1 or 2 people do all the work?

looks like a leadman, two guys holding guide ropes, a crane operator not seen, and four seagulls

CTMike

Corv said:

How well is that thing balanced?

Great question. So this generator has 1 HP turbine, 3 LP turbines, and the generator. From end to end it's probably 300' long or so, supported by 13 bearings. Typical vibrations on each bearing are less than 5 mils, so I'd say it's balanced pretty well. When something weighing close to 1000 tons (all-in) is spinning at 1,800 rpm, being out of balance would be catastrophic. That would be catastrophic to my bank account as the turbine is the whole reason the rest of the plant exists - the nuclear reactor and all associated systems are just a support system for the turbine. We put 1,300 MWe on to the grid 24/7 (except during outages), and our sister plan onsite (different design, smaller), adds another 900 MWe, so all told we are responsible for approximately 10% of the entire New England Power Grid (typical load is 20,000 - 22,000 MW depending on the weather). 

CTMike

fishlessman said:

RyanStl said:

Is that 5+ engineers standing there watching while 1 or 2 people do all the work?

looks like a leadman, two guys holding guide ropes, a crane operator not seen, and four seagulls

A load director/rigger in charge (yellow vest), 2 guys on the taglines, 1 management observer as it is a heavy lift (understatement), and some looky-loos. 

kl8ton

CTMike said:

Corv said:

How well is that thing balanced?

Great question. So this generator has 1 HP turbine, 3 LP turbines, and the generator. From end to end it's probably 300' long or so, supported by 13 bearings. Typical vibrations on each bearing are less than 5 mils, so I'd say it's balanced pretty well. When something weighing close to 1000 tons (all-in) is spinning at 1,800 rpm, being out of balance would be catastrophic. That would be catastrophic to my bank account as the turbine is the whole reason the rest of the plant exists - the nuclear reactor and all associated systems are just a support system for the turbine. We put 1,300 MWe on to the grid 24/7 (except during outages), and our sister plan onsite (different design, smaller), adds another 900 MWe, so all told we are responsible for approximately 10% of the entire New England Power Grid (typical load is 20,000 - 22,000 MW depending on the weather). 

for those of you not familiar with the 5 mil measurement, a human hair is 4 mils thick on average.  For a 300' shaft . . . that is dead nutz!  Amazing.

Lowcountrygamecock

That is really cool stuff. I’m an engineer and stuff like that still always amazes me. 

CTMike

Here are a couple of photos from the turbine deck:


Looking from the HP turbine towards the generator at the far end. The long cylindrical heat exchangers to the left and right of the turbine are moisture separator reheaters. They take the exhaust steam from the HP turbine, it is superheated, and then used to drive the 3 LP turbine stages.

That gear you see in the middle is called the jacking gear. It is used to slowly (5 rpm)  roll the turbine during heat up and cool down (very important to prevent a bowed rotor). The vertical green motor is what spins the jacking gear. 

A shot of the stator (non-rotating). The stator and it’s housing weighs north of 500 tons. It is being rewound this outage to go along with the rotor replacement. 

RRP

I for one am still in awe with this thread and information! Maybe you already mentioned and I failed to catch it….but going backwards….who manufactures this beast and bearings to such precise tolerances?

No offense meant, but you guys are just the end buyer/user which is STILL.
 Very cool to see and read about, but that piece had to have been built on a massive lathe!

littlerascal56

Mike- your pic’s bring back a lot of memories of my steam plant days in the 1978-1998 era where my crews were overhauling our Westinghouse & GE turbines, and our combustion turbines.  I started out in generation, but moved to substation maintenance & construction in 1999.  Only need 150 ton cranes for the sub work (power transformers), but had to deal with Mother Nature. Retired now, but I do have several old turbine & generator nameplates in my shop! They are pretty cool nostalgia items on the wall!

CTMike

RRP said:

I for one am still in awe with this thread and information! Maybe you already mentioned and I failed to catch it….but going backwards….who manufactures this beast and bearings to such precise tolerances?

No offense meant, but you guys are just the end buyer/user which is STILL.
 Very cool to see and read about, but that piece had to have been built on a massive lathe!

This turbine and generator were made by GE in Schenectady, NY. The plant first connected to the grid in April 1986 so a 36 year life span seems pretty good to me, since it is in operation 24/7 except for a 30 day (or so - length varies depending on work scope) shutdown every 18 months. 

CTMike

On the front end of our steam cycle, the heat from nuclear fission is used to heat water to 617 F at 2,250 psia that is then circulated through the primary side of 4 steam generators. Each steam generator supplies ~ 4 million pounds-mass/hr of dry steam (100% quality - ie: 0% moisture - water is bad for turbine blading) to spin the turbine to make the electrons to charge our iPhones. 

This is an older photo of the core being offloaded towards the beginning of an outage. 

Each rectangle is the top nozzle of a fuel assembly, each 14’ long. The blue glow you see is called Cherenkov Radiation. This occurs when a charged particle (such as an electron) travels faster than the speed of light in a given medium (in this case water). The mast sticking down in to the core bottom just left of center is the refuel machine. It lowers down and latches on to the top nozzle of an assembly and draws it up within the mast, and then transports it over to a transfer system that sends it over to the spent fuel pool, always under water. Water is an amazing shielding medium to attenuate the radiation coming from the assembly. 

Each refuel outage, 1/3 of the fuel assemblies are discharged to the spent fuel pool, and replaced with new assemblies, each ~ $1M. The remaining 2/3 are shuffled to ensure that the neutron flux profile, both radially and axially, are relatively even and within core design limits. 

If you were to give one of these assemblies a hug, you would receive a LD100 dose (lethal dose to 100% of the population) in less than 1 minute. Your death wouldn’t be instantaneous, but rather slow and incredibly agonizing. 

Here is a link to an article about a Japanese worker who received a lethal dose and was kept alive for 83 days against his will for research purposes:

https://unbelievable-facts.com/2016/12/hisashi-ouchi.html

kl8ton

So. . . thanks but no thanks for that article!  I would like the acknowledge button for it.  The pic of that poor guy in the hospital bed will stick with me a while.

JohnInCarolina

kl8ton said:

So. . . thanks but no thanks for that article!  I would like the acknowledge button for it.  The pic of that poor guy in the hospital bed will stick with me a while.

It has got to be the worst way to die.  At some point morphine and other sedatives don’t do any good, because the veins themselves are breaking down.