Building a better Nuke Plant

[Tech-A]

I was reading about the "NEW" Nuke plants that are being designed and what would the Nukeworkers want in a design. Like for example, When it comes to refueling a PWR a lot of radiation and contamination is involved comes from the inspection of the S/G tubes. But, if the Primary and secondary water was reversed so the the reactor coolant was on the outside of the tubes, then there would be less contamination and radiation.

[SloGlo]

oh i hate it when i don't understand new technologies......

[Rain Man]

Primary coolant on the secondary side of a generator??  It has been unintentionally tried by many utilities.  Sloglo..This is a new "technology" you don't want to know about.

[RDTroja]

I'm with you, SloGlo -- I just don't understand how that would be a good thing.

[raddad]

Let us not forget the purpose of the S/G -- to make steam.  It won't work unless the hot water is in the tubes and the feedwater outside.

[Tech-A]

A S/G is just a heat exchanger, I souldnt make any difference if the Hot water is inside the tubes or outside. And put the Primary Separators in the Turbine Building.But I could be wrong on the thermodynamic part. Time to go hit the books...

[SloGlo]

'cuse me, today is as slow as yesterday, apparently.  i thought the design change was to reduce radiation/contamination concerns, and here we are pumping primary to the turbine bldg?  maybe we should just eliminate those pesky S/G thingys and spin the tubine with the primary coolant in it's original steam mode?

[rooyou2]

yeah, we could get rid of those pesky S/G thingys, just take the steam right from off of the core.  We could even put in some kind of box whatchamacallit with zig zag paths to trap out the moisture to help save the turbine blades.  Hey! We could even put in some kind of dryer thingy after the moisture one to... Oh!...never mind.

[Rain Man]

Sloglo and rooYou2 have it...a new design....the P/BWR.

[SloGlo]

P/BWR; wasn't that the design change that toledo edison had in mind in the 89 -90 cycle?

[Raymond_Blurr]

Wouldn't work without feedwater pumps the size of RCP's.  Remember the cause of leakage from primary to secondary is RCS pressure at ~2250 psi. leaking through the SG tubing into a much lower pressure. Not economical to run FW at greater than RCS pressures because of the need for increased piping thickness', higher capacity pumps, having to cool the FW again due to the heat added by the RCP sized FW pumps, and so on....glad to see someone using their noggin, but it just isn't good design for something that rarely ever happens.  

[Tech-A]

The reason behind the topic is to point out plant design problems that contribute to higher contamination and radiation exsposure. Take S/G platforms, Most are crampt and hard to get to, hard to decon. Being a deconner at one time it takes a lot longer to decon a platform with a bunch of equipment around in a crampt place. Need a drawing board on here to explain the S/G "heat exchanger" design. "Think outside the box"

[Raymond_Blurr]

The "box" is called heat transfer and fluid flow.  Your original proposal was to reverse the primary and secondary to reduce dose and contamination. It wouldn't be viable no matter how far outside the "Box" you think.  Sorry

[Already Gone]

Actually, if you've ever worked at a dirt-burner, you'd know that the feedwater does go inside the tubes.  It would be kinda hard to get the fire on the inside.
If you have a once-through type s/g, you could do it.  I just don't think that the heat transfer would be as efficient.
If your aim is to control the spread of contamination and minimize exposure, there are some more practical design changes that would work well.
1- Put each s/g into a cubicle, with a smooth, solid floor and a door.  Make it big enough to work in without crawling.
2- Put the manways where you can get into them without a ladder, a hydraulic jack, an umbrella and a tube of KY.
3- Install permanent piping for things that are always needed; like DI water, tool air, ventillation, air sampling...etc.
4- Build in pass-through portals for tools, equipment, trash, laundry...etc.
Essentially, just build the plant as if you were actually going to do the things that you will actually do.

[Tech-A]

Thats right beer court, The S/G would be a straight through design. Plus the problems and time consumed going to Mid-loop and installing nozzle dams would also be eliminated. Also the other designs you said are great ideas.

[pete_shonkwiler]

Of course, it wouldn't matter by how much of a percentage one would increase the cost of plant construction.  The most important thing would be to minimalize the incidental headaches to the occasion workers involved therein.  While one is at it, perhaps the possibility of the installation of remote camera operated spray jets, ala a car wash, in order to remove the necessity of decontamination workers involvement in the operation of component work.  Perhaps one could also install remote teledosimetry, air sampling,  and other new age gadgetry and reduce the number of migrant nuclear whiners, too.

[mdkent11k]

You say sarcastically to install things to keep the road techs from whining.  Me thinks you whine to much.

In today's environment I have seen plants that are making design changes to install things such as camera cords and computer terminal connections permanently.  Your suggestion goes back to what has got this industry in the situation it is in. Why pay for today if you can put it off to tomorrow.  

I understand on a Sub why things are cramp.  But making a work space that will have to be accessed routinely not user friendly is just poor engineering.  And if you are wondering about the cost, well figure out the extra man hours used in accessing these areas, versus if these area were design correctly in the first place, or routinely used devices were permanently installed.   Why do you think newer plants are pulling 17 day outages while the older plants are happy with 25 day outages.  At a million dollars a day shutdown, figuring forty year life, and eighteen month fuel cycle, that is roughly 186 million saved.  That is a lot of creature comfort you could install for those "whiny road techs".  And this number does not even include unplanned outages, God forbid.

[pete_shonkwiler]

"Why pay for today if you can put it off to tomorrow. " 

In today's economic enviroment,service based economy and all, one is able to bill rate payers for outages, but not for construction costs, if I remember my nuke econ class correctly.  If I haven't, I am sure to be corrected quickly.

"But making a work space that will have to be accessed routinely not user friendly is just poor engineering."

Last time I checked, Containment structures were not designed to be routinely accessed.  Those Containments that were designed for routine accessibility, surely did not intend for the Steam Generator Manways to be opened on a routine basis.  Now if you would like to design such a system, be my guest, however, it is difficult enough to get plants licensed under the current philosphies of radiation controls.

[Piston]

Alot of those new inventions would put alot of you out of a job  

[Chimera]

hmmmm . . . as to that steam generator/heat exchanger thingy: It might be better to reverse th sides of th S/G except that you need a large volume for the steam.  It's not just a simple heat exchanger.  The once-through design is the closest to that idea.  As far as that goes, imagine all the crud traps in between those tubes if the primary side was on the outside of the tubes.  Scarey ain't it.  Doesn't sound like it reduces the dose rates at all.

It just ain't profitable to spend a lot of construction dollars on a place that is designed to be occupied less than 0.5% of the time.  While there is always room for some improvements, including too many so-called "creature comforts" in the construction side of the plant isn't cost effective.

Locations for permanent installation of cameras and other equipment must be carefully evaluated.  You wouldn't believe the effects of high-energy ionizing radiation on solid state components and wiring over time.

As for me, I'm just happy to have a job that I don't have to work at 365 days a year.

[Rain Man]

The "maple syrup swilling squirrel lovers" of the Clam Shell Alliance will tell you dose and contamination can be reduced by closing all the nuke plants.....Hope they get some rolling blackouts this winter or next summer.

[Already Gone]

Some of you have made some good points.  If new plants were designed better I would no longer get paid to provide ten days of job coverage for carpenters to build the same scaffolds one outage after another.  Too bad.  I always thought it made sense to spend a week erecting a platform that will be used for three days.

[DainJer]

Notice Beer Court...every outage we have there are around 60 to 80 of those Scaffolds labeled Permanent. Byron was cut down to less than 500 scaffold this year. thats hundreds less than usual.

[mdkent11k]

In today's economic enviroment,service based economy and all, one is able to bill rate payers for outages, but not for construction costs, if I remember my nuke econ class correctly.  If I haven't, I am sure to be corrected quickly.

Last time I checked, Containment structures were not designed to be routinely accessed.  Those Containments that were designed for routine accessibility, surely did not intend for the Steam Generator Manways to be opened on a routine basis.  Now if you would like to design such a system, be my guest, however, it is difficult enough to get plants licensed under the current philosphies of radiation controls.

Sir, you have it exactly 180 degrees out of phase.  You can bill the rate payer for a new plant, but a SCHEDULED outage you cannot pass on to the rate payer.  Now if you come up from the outage and a day later you trip, so be it, the rate payer gonna pay.

Second....  Containment Structures ARE routinely accessed.  Sometimes daily, depending on the plant.  This ain't the old world you must be accustomed to.  And by routinely, sorry I did not SPELL IT OUT FOR YOU, by routinely I meant MULTIPLE TIMES IN A PLANTS LIFE.  You build the SG Man way more accessible, you cut down on dose, and on time.  WIN WIN.  Now what does the accessability of the man ways have to do with licencing.  I tell you what NOTHING.  The NRC does not care if you have to have two men and a small boy to access your SG's, as long as the plant is safe.  

Care to throw out anymore key words and tricky phrases?

[mdkent11k]

Locations for permanent installation of cameras and other equipment must be carefully evaluated.  You wouldn't believe the effects of high-energy ionizing radiation on solid state components and wiring over time.

RAAADIAATION?
Why would one want to permanently install camera's?  The wiring and connections yes, the camera no.  And the wiring, all the other I&C (RTD, Pressure Det., NI etc..) seem to last.  

When you shut down, pop in and install the camera's and other associated equipment and your good to go.  A lot less time spent routing cables.