NukeWorker Forum
Reference, Questions and Help => Nuke Q&A => Lessons Learned => Topic started by: TENN-1 on Jun 09, 2008, 11:16
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I am looking for a station with a working Mirror Insulation refurbishment program. Especially, what type of decon techniques are being used to remove heavy internal deposits of boric acid from large pieces of mirror insulation. I hear stories of hot water submersion baths and ultrasonic sinks but have not found any factual information on the subject. Handling the stuff we have is becoming very touchy and manufacturing new pieces will probably not be cost effective. We need a new approach. Any new equipment available or lessons learned out there?
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What is cost effective is getting rid of the old stuff and replacing it with new. I was involved with the Unit 1 recovery at Browns Ferry. I was the tech covering the Drywell mirror insulation decon effort after many fruitless attempts to knock down the levels we finally came tothe conclusion to replce everything. Don't waste you time get rid of the old stuff.
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Thanks for the reply IE. Replacing the insulation is always an option. We have been told unofficially the figures could run into seven figures for a total replacement. That's why we're looking at all options. Good news for you that yours was replaced - we are not there yet.
Any other ideas out there?
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davis besse used a ultra sonic machine.worked good at knocking down dose rates
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Frisher is right, during the 2 year outage - Davis Besse had to remove and decon the majority of their mirror insulation. We set up a ultra sonic unit in their train bay and went to work. Some work required respiratory - some did not. Tech coverage at all times while the men are working - more of a contamination problem if not monitored properly. The only problem that I am aware of - one tech wasn't aware the hepa had shut down - contamination leaked out behind the work area and migrated around the area and into the train bay area. I think it took a day to recover from that mess. Dose rates / contamination levels dropped significantly. I have PM'd some phone numbers - you can call to discuss with the techs / supervisors involved with this.
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Now we're talking! I'll give you a call today for details. Thanks!
Anybody doing this type of refurbishment today?
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We just let it fall one year at Yankee Rowe...literally..right off the genny and onto the deck! Wiped it off and put it back on...most of it anyway.
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I was at Millstone Unit 2, when we dealt with alot of Mirror Insulation decon. We used a steam Ginny in a tent in the basement over the sumps grates..with plastics and resp prot. etc...it seemed to clean up fine BUT..as soon as it dried ..the inner baffles released contamination as we had crews snapping it back into place...unfortunately it was too late in the outage to fabricate or even order new insulation..i think George Young was in charge of the decon effort and Al Johnson ctmt maintenance..im not sure who was in charge of Rp then ( its been awhile) but Al Johnson would be your best bet i think.
Peace !
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My question isn't about deconning the Mirror insulation so much as to if there have been a number of issues with the buckle style clasps popping off while the insulation is being installed