Noble gas

[Rennhack]

A gaseous chemical element that does not readily enter into chemical combination with other elements. An inert gas. Examples are helium, argon, krypton, xenon, and radon.

[wlrun3@aol.com]

   
   Shutdown Palisades 9/9/07...1R19...35 days...four leaking fuel assemblies...noble gas/iodine situation has challenged mechanical/administrative systems of control.

   In addition, Cs137/Co58, have solid presence in body count data.

   Best industry example of how to implement controls for noble gas/iodine situation with large outage worker population (PCM 2s, PM 7s, Canberra Fastscan) needed.

   

[Marvin]

Ok, old brain cells.  Not sure they work anymore.  I would like to think that some of the techs with more recent gas experience would chime in here.  I remember a few things.

1.)  It wasn't one big thing that helped but a lot of little things.
2.)  Ask folks to wear modesties if they go in gas areas.
3.)  Make sure the techs have their open air ion chambers bagged.  Burn the gas out (low temperature heat {don't forget to remove the batteries first}) after background creeps.  The bags are only good for so long. 
4.)  Establish "frisker monitors" with logsheets if you haven't already.  Doesn't have to be an RCT.
5.)  Herculite doorways in the aux building where gas from critical support systems can escape into the hallways.
6.)  Include discussions on the gas in your pre-job briefs.
7.)  Ventilation is of course critical - check your ventilation pathways to make sure the gas stays where you want it to stay.
8.)  Check your doors - should doors that are open for the outage be shut?
9.)  Make sure your iodine cartridges are not sitting around getting gassed up before you turn the air sample pump on - makes for a frustrating scenario when all the cartridges have pre-existing counts.
10.)  Consider having one of the HP management type folks draft/approve a white paper to get folks out of the RCA and on the way home if certain conditions are met.
11.) Setup chairs / benches close to the PCM's so folks have a place to sit while they are waiting for decay.
12.) Have modesties (or similar) at the egress and give folks a chance to change into clean clothes.
13.) Bag, tag, and control personal clothing until it has had a chance to decay.
14.) Rotate refueling floor techs with too much iodine into admin positions if it gets really bad.
15.) Control your portable HEPA's and HEPA vacs with a vengeance.  Some poor young tech or deconner could blow iodine all over the place if they don't have the big picture (not that it has ever happened before).
16.) Iodine filters downstream of HEPA's on your portable blowers.  Establish dose rate thresholds, make sure they get monitored, and so on and so forth.
17.) Oh, and did I mention the little particles that will start to show up in strange places.
18.) Beat complacency back with a stick.  It's easy to let the little particles out when the gas shows up.  People get tired of waiting and the "it's just gas" gremlins are sure to show up.

I'm sure there's more.  Anyway....you're all sure to learn a lot this outage.  There's a silver lining to every cloud, even a gas cloud.

[retired nuke]

Ok, old brain cells.  Not sure they work anymore.  I would like to think that some of the techs with more recent gas experience would chime in here.  I remember a few things.
...
I'm sure there's more.  Anyway....you're all sure to learn a lot this outage.  There's a silver lining to every cloud, even a gas cloud.

I bet that's more information than Entergy gathered during the RPM phone conference - hope somebody there listens. Awesome advice, and looks like you have experienced it....