GE 360 Platform

[retired nuke]

OK, here are a few questions about the 360 platform that is coming into use at BWRs everywhere....or so I'm told. Anybody that has worked with it that wants to share facts and opinions, please jump in. This is supposed to allow IVVI, etc while fuel shuffle is taking place, by standing in a circular tub just above water level, while the fuel bridge passes over you...sounds interesting. 

How much time / hassle / dose to set it up? - I've heard 10 seavans of equipment, 1000 manhours to put it together, etc.

What are the dose rates in the work area inside it vs. the dose rates on the bridge, where IVVI "usta" be done? Is shielding effective? Underwater pressure washing to reduce crud / dose rates? How often?

At the end of the outage, when everything is flying to get buttoned up - how much problem is this beast to put away? Any tips for contamination control / decon / what order to do things?

As you can probably tell, I haven't seen it, but it is coming to us (VY) in the late spring. It is supposed to save schedule time, but I am trying to figure out at what cost. Obviously, a couple of extra Rem vs a day of outage time is worth it, but I would like things to go smoothly....

[vikingfan]

  Snake I have used the areva version of the tub at both peach bottom and most recently at cooper.I'm not sure of the manhours involved in setting it up, at cooper it was already assembled prior to the outage so just basically had to be bolted down.I will say the doserates we had in the tub were generally 1-5 mr/hr.

[vikingfan]

     pet snake,
there are a couple pictures of the "tub" in the cooper section of the photo gallery. also there never was a need for shielding from what i saw, even during the fuel shuffles.hope this helps you somewhat.

[wlrun3@aol.com]

   GA in work platform...1-3

  Crud trap created by plastic in-mast fuel sipping discharge hose...100/25...which is directly overhead platform workers as refuel bridge transits vessel

  Entering and exiting work platform, poles and equipment extending above head height, work platform foreign material exclusion zone documentation...all sources of previous complications

  Telepole, latex gloves, dry rags, telemetry


 

   

[vikingfan]

yea the discharge hose from the mast sipping equipment can be hot. and the clearence of an average man lets say 5'10" to the bottom of the refuel bridge is only about a couple of feet, so the worker need to be cognizant of the clearence when they are attaching or detaching bwr poles. Also workers need to be aware of the equipment in relationship to where they are working so they can minimize or eliminate any items that could fall in, just ask peach bottom. but overall it is a decent place to work that won't compromise the fuel shuffles and you can do IVVI and fuel shuffles in unison.

[UncaBuffalo]

Columbia built their own version of this platform and used it last outage. 

It worked fine until it came time to pull it out of the pool.  Then it became obvious that there were too many areas under the platform that could not be sprayed off with the hydrolaser.  When the platform was landed, the technician that went underneath to survey had a locked high-rad bag of smears in the first 1/4 of the platform and bailed out.  The platform was wrapped and left sitting for several months until a decon plan could be prepared.

I would assume GE's platform is better designed, but make sure you do enough pre-planning so you don't have problems when it comes out of the pool.

[cfradgal]

We just brought the GE 360 platform out of the water a couple of days ago at Hatch. It did not go too well.
Has anyone worked at a plant that had a good decon plan for this piece of "equipment"? Of course, this was a huge learning curve for us.
Leaching was a huge problem. The more they deconned, the worse it got. We had 3 Personnel contaminations, 1 was an uptake(from touching their nose). Almost anyone on the refueling floor at that time, lost their clothes/scrubs...distributed contamination.
We'll be better prepared next time, hopefully.

[vikingfan]

did you cut off their fingers for touching their nose in a contamination zone as for decon how did you decon it ? did you use a undrwater wand to pressure wash the bottom of the tub before removing it from the water ? and what decon solution do you guys use after it is placed back on the floor ?

[alphadude]

a good decon plan for this equipment is have some one there when the "engineer (where is the reactor?) type" designed the item. duh!

[cfradgal]

We did use an underwater wand to wash the bottom of the tub.  We used a solution called Epicor, ( contains TRISODIUM PHOSPHATE, SODIUM HYDROXIDE & IONIC DETERGENTS).  We also used Syntech, scotchbrite, etc. It started out at 100K dpm and kept getting worse.
And, we only cut off 1 finger for touching noses   

[alphadude]

well duh- hydroxides render iron oxides insoluable. you are lucky that the stuff didnt create a passified surface of black oxide. (you will never get that off). The first rinse should have been a weak ammonia solution to remove any boric acid. (if you were borated)  Then a nuclear grade sufactant with an weak acid solution (citric acid). And lots of hot hot water.  The formula you used is just the opposite of what should have been used.  The solution you used is for organics, fats, greases and oils.

I guess nuclear grade decon is a lost art....

[retired nuke]

well duh- hydroxides render iron oxides insoluable. you are lucky that the stuff didnt create a passified surface of black oxide. (you will never get that off). The first rinse should have been a weak ammonia solution to remove any boric acid. (if you were borated)  Then a nuclear grade sufactant with an weak acid solution (citric acid). And lots of hot hot water.  The formula you used is just the opposite of what should have been used.  The solution you used is for organics, fats, greases and oils.

I guess nuclear grade decon is a lost art....

Dude,

you are correct - nuclear grade decon is a lost art. I did not know any of what you posted about hydroxides, etc. I will save the post for future reference, thanks. 

We have nobody here (maybe Chemistry) that would know that info. The only decon material we use is Syntech(spray on foam), water, or BNI Stripcoat.
Do you think the stripcoat would be effective? It smells vaguely of ammonia. I'm just an RP tech, and only deconned briefly long long ago.
Thanks for your post, and the info you provide 

[cfradgal]

Funny, with all the technical information that has been passed around about this GE platform, no one has discussed the types of solutions to use or not to use. And I'm not talking about this website.  There had to be major discussions before this piece of equipment was bought between GE and the utility. I was not privy to any of that. Our GE site management knows the type of solutions we use because they have to approve them.
We are a BWR, so would the weak ammonia solution still be beneficial?

[alphadude]

typically, the designers are not to savy on decon solutions, the weak ammonia should be the first rinse and will not harm typical alloys used in nuke. this will remove some Cs and any boric acid which tends to hold onto things. the formula mentioned previously is a degreasing formula that will prep the metal for immmersion into high purity systems but dont work worth a darn on metal oxides. the platform may not be deconnable..due to poor design or needed design (angles and dangles).  I would use the ammonia, hot water rinse, then some simple detergent with lots of muscle ... If you have lots of angles and dangles do not use the alara paint, you will never get it on properly and get it off properly.

[SloGlo]

sounds like maybe it'd be a good idea to write decon into the contract with ge, making it their responsibility.  that way, they'd only have to decon it to their license specs.

[mattrev]

typically, the designers are not to savy on decon solutions, the weak ammonia should be the first rinse and will not harm typical alloys used in nuke. this will remove some Cs and any boric acid which tends to hold onto things. the formula mentioned previously is a degreasing formula that will prep the metal for immmersion into high purity systems but dont work worth a darn on metal oxides. the platform may not be deconnable..due to poor design or needed design (angles and dangles).  I would use the ammonia, hot water rinse, then some simple detergent with lots of muscle ... If you have lots of angles and dangles do not use the alara paint, you will never get it on properly and get it off properly.

I'll have to look it up, but I think you'll find ammonia based products aren't allowed by the GE Red Book. That's why Windex isn't allowed in most RCA's.

[alphadude]

more than likely not.. but sometimes you have to push it to get what you want. The use of TSP and the other junk is a lot more hazardous than 1% volatile ammonia. But just because the vendor says its approved don't mean it will work.. like I said earlier.. those design engineers dont  think about decon too much when it comes to real world situations.. otherwise we would not be having this conversation.  Total risk assessment hasnt trickled down to them yet!  Hot water could be used to remove any boric acid film. Then use a simple non-alkaline detergent and a scrub brush.

I had another idea but good luck on using that.. rinse in hot water to remove the boric acid film. Then use copius amounts of WD 40 to float the metal oxide then wash it off with a simple non-alkaline detergent and a scrub brush.  But as I said earlier- alkaline detergents such as TSP and hydroxides will passify the surface and make the metal oxides more insoluable than before.  The 1% ammonia isnt strong enuff to do that it only goes after the boric acid film.

Good luck!

[UncaBuffalo]

...as for decon how did you decon it ? did you use a underwater wand to pressure wash the bottom of the tub before removing it from the water ? ...

You can get a much higher decon factor while using the U/W wand if you have a U/W camera showing you all the nooks & crannies...you'll actually be able to see the floaties coming off as you spray in the worst areas.

Do you think the stripcoat would be effective?

We had great luck with it, but proceed with caution...each stripped wad the size of a baseball was a high-rad area...5 wads together made a locked high rad area...be ready to post accordingly & verify your limits for extremity monitoring aren't exceeded...and have your HIC pre-staged on the refuel floor so the stripped paint can go straight into it & not get handled multiple times.

[Laundry Man]

Past experience has shown me that when it comes time to decon the "Scorpion" as it was called last time I was involved, schedule pressure is the number one factor.  There is never enough time to do the job correctly.  Most of us have seen it, just pull it and wrap the bottom, we can clean it after the outage.  When the final IVVI is complete and signed off, all the refuel guys want to do is pull the platform and drain down as that is usually a major outage milestone (and one less beating at turnover because you actually got it done).  The refuel guys don't really care if you loose the floor, that would be RPs problem. 
LM