Charges on Hot Particles

[grantime]

I know that DRP (hot particles) have a static charge.  Do you know if they are positively or negatively charged?

Has anyone tried using electrostatic collectors to capture DRP's?  We have issues when purge is down and CTMT doors are open of particles blowing out to clean areas.

[SloGlo]

eye tried gathering those little things with a electrostatic device, but i wore out my thumb pushing that little button reely fast!

re: charge.  that wood depend.  the particle itself is positively charged.  unless it's brand spanking new, it which case it's charge is neutral i.e. prior to beta decay.  butt, if you want the whole deal, then you got two deal with the little electrons all around it, the electron cloud if you will.  these will take on a more negative charge.  after a bit, sum of those little buggers will go back due to charge differential.  finally, equilibrium gets established and neither charge increases. at which case you have a postively charged particle due to the initial loss of electrons.

Butt, i'm thinking your probably going to grab a bunch of other material which will cause bulking of the particle, the hulk effect.

[wlrun3@aol.com]

   I have seen this problem successfully addressed at Surry and Peach Bottom with a formalized sticky pad program.
  Routine shiftly surveys incorporate collection and counting of the pads, first by frisker then by small article monitor, and the results documented on the routine survey.
  This process is similar to the informal tracking that occurs for <100 ncpm/probe area indications on personnel exiting RCAs and is controlled/monitored by the shift tech.
  The pattern that develops, especially during containment or auxiliary building purge compromise, quickly identifies the release path before migration beyond the RCA boundary occurs.

[GLW]

I know that DRP (hot particles) have a static charge.  Do you know if they are positively or negatively charged?

Has anyone tried using electrostatic collectors to capture DRP's?  We have issues when purge is down and CTMT doors are open of particles blowing out to clean areas.

You can do your own determination to evaluate if the particles are negatively or positively charged.

Positron decay is limited to nuclei where the absolute value of the binding energy of the daughter nucleus is higher than that of the mother nucleus.

If you know your specific decay chains and nuclide distributions, you can extrapolate your probabilistic populations of beta minus and beta plus emissions.

Work that into a laymans emission probability ratio for your DRP's and you should be able to develop a defensible model for any given moment in time.

and I know you know how to do that, I've read your work,....

as always, crack open the related NCRP's and ICRP's in your plant's tech library for in-depth reference,...

of course,....the sticky pads work real nice too,...

I've never tried to use any electrostatic "vacuum", can't help you there, but it is a big pool of folks around here,...



PS - Tell Mark S. I said hello next time you see him,...

[GLW]

eye tried gathering those little things with a electrostatic device, but i wore out my thumb pushing that little button reely fast!

re: charge.  that wood depend.  the particle itself is positively charged.  unless it's brand spanking new, it which case it's charge is neutral i.e. prior to beta decay.  butt, if you want the whole deal, then you got two deal with the little electrons all around it, the electron cloud if you will.  these will take on a more negative charge.  after a bit, sum of those little buggers will go back due to charge differential.  finally, equilibrium gets established and neither charge increases. at which case you have a postively charged particle due to the initial loss of electrons.

Butt, i'm thinking your probably going to grab a bunch of other material which will cause bulking of the particle, the hulk effect.

yeah, what he said,......if you speak pittsburgheez,....

[grantime]

Sticky pads do work but not as well as we hoped.  This particular situation has significant airflow and the particles are very mobile.    I had (wild???) idea that perhaps a charged plate would be more effective.

Just have to figure a way to try it without electrocuting anyone...  for some reason people don't like being shocked   

[grantime]

We know how to find them.  We even manage to catch a significant number on sticky pads and massilin mops. 

The problem is the we also are successful in capturing them on workers clothing.  Then the bean counts get out of tolerance.  My goal is to find way to capture them before we find them with PCM's. 

[wlrun3@aol.com]

   Step off pads, double Orex, booties and gloves in areas of your choice given the purge inadequacy is your next option.
  There should be no reason to survey for particles on the outer set any more than you would survey for distributed contamination on the outer set.
   This will eliminate DRP migration via personnel clothing to the RCA egress point.

   Over the years I have seen electro-mechanical electrostatic charge neutralization approaches at Columia, Fermi and Clinton, all with negligible success. The problem has always been the inadequacy of the electric field introduced given the intensity and dynamic nature of electrostatic charges in the work areas.
  The most effective method for protection against DRP collection on personnel clothing has been the use of static charge neutralization spray used in the semi-conductor industry.
   This method, used primarily to mitigate Radon interference, is currently being used at Columbia with significant success by Security and Operation personnel.



 

[grantime]

Our problem is these are migrating to clean side of SOP

[wlrun3@aol.com]

Can you use double step off pads with buffer zones without engaging the DRP procedure?

[SloGlo]

I bet you're getting them on the clean side of the sop.  little devils are energentic, used to chase them around trojan n.p.p. back in the day.  use of anything that generates a static charge will help, plastic walls around your sop area can be a positive factor in maintenance of the clean side.  bee sure two masslin the "hot" side frequently to capture what's there.   a waist high cattle chute of plastic walls can be used, as the workers passing thru it on the way to the drums for discards generate a charge on the plastic which can help hold those fleas.  again, masslin frequently.  sticky pads in the area of disrobing can assist in minimizing migration.  negative ventilation is always a plus.

[nuke_girl]

Im not sure how large your ctmt sop is for egress but i have seen a similar issue at Harris years ago addressed by a engineering change in the design of the pad. they enlarged it and brought it around a corner from the entrance hatch. They also laid a diamond cut plastic down much thicker than a herculite so it could be deconned easier. There was a column of dress down drums with all the appropriate sticky pads. The final touch was a large Hepa vac decon effort  on all floor surfaces 2 times a shift. The particles were stopped at the SOP line, the effort was successful. I personally think the change in design for the sop configuration  had alot to do with it.

[LaFeet]

Coat everyone with "Static Guard" prior to their entry....?

Double pc's seem to be the best choice, perhaps couple that with negative ventilation.

[wlrun3@aol.com]

I believe Mr. Warnock of San Onofre would have something to say about this topic, especially electrostatic collection methods.

[Safety Matt]

I had (wild???) idea that perhaps a charged plate would be more effective.

Just have to figure a way to try it without electrocuting anyone...  for some reason people don't like being shocked   

If my memory serves me correctly, we tried something similar at Trojan after their major fuel failure.  Step on the charged pad before you frisk at the RCA exit (pre PCM-7) and in theory the fleas fall off the host and stay behind the magic line.

You may want to touch base with the old guys at SONGS...FLEAS didn't get the moniker by accident (Found Loose Everywhere At Songs).

[UncaBuffalo]

Step off pads, double Orex, booties and gloves in areas of your choice given the purge inadequacy is your next option.

Double pc's seem to be the best choice, perhaps couple that with negative ventilation.

My apologies in advance to wlrun3 and LaFeet, both of whom I have worked with and greatly respect, BUT...



I so hate hearing people recommend double pc's for a problem that is a 'bean counter' issue instead of a genuine radiological hazard.

We all know that the worker isn't getting significant dose from the activity of specks that we are (over) reacting to at most plants.  We only do these outrageous controls so we don't have to document a PerCon and get in trouble with INPO.  In the meantime, we are putting HUGE heat stress on the workers and (if we haven't already) will soon kill some poor guy that was just trying to get his work done.

Just say 'NO!'  Make a decision based on a true weighing of the costs/benefits for the health of the worker...and tell INPO to get a clue.

We did this same BS with respirators 20 years ago.  The NRC finally made us quit killing people with over-use of respirators.  Let's take the initiative this time and do some REAL protection of the worker.



JMO

[wlrun3@aol.com]

In general...
Co59~radiologically stable and electrically neutral.
Co59+n~electrically neutral and radioactive Co60.
Co60 emits B negative~electrically positive and radiologically stable Ni60.
So wouldn't a Co60 DRP be electrically neutral and the electrostatic charge incidental to it's surroundings, static accumulation and metallurgical composition?
So how does a Co60 "hot particle" inherently and initially possess a charge?
Why are "hot particles", as we know they are, strongly effected by electric fields, especially static?

[wlrun3@aol.com]

   I'm so glad that some one like uncabuffalo, who was there when we first heard of "hot particles", is part of this.
   How does an RP Supervisor respond when asked at the management meeting what measures we've put in place to mitigate the current DRP personnel contamination issue in light of an upcoming INPO inspection?
   Remember how rediculous it became. North Anna-doubles everywhere in containment, "hot particle" stay times, buffer zones, exposed skin surveys including by uncapped teletector probe. Palo Verde-grid survey of the entire refuel mast with customized slotted window RO2 that had the chamber 3/4 filled with styrofoam.
   Hopefully whatever Grantime decides to do on this, the common sense that has always been the Alara concept will prevail.

[UncaBuffalo]

  How does an RP Supervisor respond when asked at the management meeting what measures we've put in place to mitigate the current DRP personnel contamination issue in light of an upcoming INPO inspection?

I guess on a macro-scale, I say the answer is to push back against INPO.  Make a stand.  Tell them it's stupid.  Fix the problem before we kill (more) people with heat stress.

http://www.nukeworker.com/forum/index.php/topic,25113.msg128480.html#msg128480


On a personal day-to-day basis...?  I realize that we can't fix every problem by ourselves.  I do not push for grand Save-The-World gestures on every single fight.  That would cause us to lose credibility and we couldn't effect change elsewhere.  

BUT, do take time to look at each case separately.  Is this a battle that I've already lost? Or can I advocate common sense and save a life?  I owe it to the workers (and myself) to do the 'best' thing, rather than willy-nilly putting them in too much gear.

DON'T JUST DEFAULT TO DOUBLE PCs AT THE DROP OF A DRP!





modified for spelling

[UncaBuffalo]

Has anyone tried using electrostatic collectors to capture DRP's?

Sorry I hijacked with my INPO/PerCon rant...   We now return this thread to its regularly scheduled program, already in progress...   

Let me know if you have any success with your collectors...I love science projects!   

[grantime]

I so hate hearing people recommend double pc's for a problem that is a 'bean counter' issue instead of a genuine radiological hazard.

We all know that the worker isn't getting significant dose from the activity of specks that we are (over) reacting to at most plants.  We only do these outrageous controls so we don't have to document a PerCon and get in trouble with INPO.  In the meantime, we are putting HUGE heat stress on the workers and (if we haven't already) will soon kill some poor guy that was just trying to get his work done.

Just say 'NO!'  Make a decision based on a true weighing of the costs/benefits for the health of the worker...and tell INPO to get a clue.

We did this same BS with respirators 20 years ago.  The NRC finally made us quit killing people with over-use of respirators.  Let's take the initiative this time and do some REAL protection of the worker.

AMEN BROTHER!!!!  PREACH ON!!!!

[grantime]

At least the insanity is a bit lower than it was when Hot Particles were "invented".  I was sent into transfer canal with double PC's , Double Plastics, and a Respirator(only one of those)   because of DRP's. 

wlrun3 has a good point about electric field.  To make electric field strong enough to do any good will require higher voltages--increasing risk of shock.  Doubt I can sell that to management.  Maybe I can talk them into antistatic spray instead. 

Thanks for all the input.   Where else can you get this kind of help?

[macgator]

In general...
Co59~radiologically stable and electrically neutral.
Co59+n~electrically neutral and radioactive Co60.
Co60 emits B negative~electrically positive and radiologically stable Ni60.
So wouldn't a Co60 DRP be electrically neutral and the electrostatic charge incidental to it's surroundings, static accumulation and metallurgical composition?
So how does a Co60 "hot particle" inherently and initially possess a charge?
Why are "hot particles", as we know they are, strongly effected by electric fields, especially static?

The random removal of electrons via compton scattering, pair production, photoelectric effect or the production of Auger electrons will cause the particle to be charged.

[LaFeet]

UB  I agree, the knee jerk reaction for Double PCs may be unjustified.  I do not know all that is involved without being there.

All in all, I hope you folks solve your flea problem, and soon.

[Chimera]

Assuming you're treating the "DRP Zone" as a high contamination area within a contamination area, the double PCs make sense.  Given that this problem has been around for over thirty years, it looks like vigilence and a good roll of duct tape at the step-off pad are still the best defense.