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.

[retired nuke]

What is the activity level of the DRPs?

If reasonably low, calculate what time period would keep you under a skin dose threshold (<xx mR unplanned skin?) and make the stay time in CAs be less than this. I forget where - but one of the places I worked had a 2 hour stay time in CAs due to particles. They had calculated that if their (90% CF) larger DRP jumped on you when you walked in, and stayed there for 2.5 hours, it would be <XX mR skin dose, a level that they decided was acceptable risk.

Had an interesting discussion with a region RP inspector about PCEs - NRC is a honey badger about PCEs.... just sayin...

[grantime]

all ranges of activity but most pretty low.  More of issue for bean count than for skin dose.  You know the drill --- it must be poor rad worker practice if we didn't see the particle jump on them.   Must stop all poor radworker practices.  therefore must stop all fleas.....

[SloGlo]

thank God i don't have two deal with this level of bean counting!  i'd probably invite him to bring his flashlight inside the big round thing to show me the fleas jumping up on the rad workers.  while he was at it, maybe he could grab one of those little buggers 'n verify it's sex.  keep them from breeding.  give him sum thing too count besides beans. 

[LaFeet]

SloGo for containment co-ordinator !!!!!!   

[OldHP]

Had an interesting discussion with a region RP inspector about PCEs - NRC is a honey badger about PCEs.... just sayin... 

thank God i don't have two deal with this level of bean counting! 

Unfortunately 'Our Friends' from INPO don't always view things in the safest prospective.  They took the same attitude many years ago with the reduction in respirator use.  A lot of them didn't understand that if you could cut the external dose substantially by cutting the task time, lessen the body stresses, and make the job safer at the cost of a few (<10 mrem) mrem internal that that was proactive ALARA!

The issue of a small dose to the skin from a 'hot particle' vs. overall body/limb contamination due to poor work practices or poor work control should be two different issues.  They don't see it that way.  When you add significant PC protection and cause an increase in task time (adding to external dose) and increase the body stresses, that is not ALARA.

Oh, for the days when if it came off on the first attempt/wash, it wasn't a PCE!

[wlrun3@aol.com]

"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."

So most will have net positive charge.

If we used D cell batteries, some wire and standard 50 sheet sticky pads could we build net negatively charged sticky pads?

We could use smoke testing to map and document air flow using the simple, cheap and MSDS friendly smoke generators I saw in use at Rocky Flats, a plutonium alpha environment.

We could place the charged sticky pads according to the smoke test migration path results.

Then we could incorporate our routine sticky pad surveys, using friskers and SAMs, into our documented routine survey program and amend the procedure.

"As you can see, our RP Department has successfully addressed the personnel DRP contamination issue by instituting, through administrative and engineering controls, a program that has, as shown in the amended procedure, smoke test identified migration route maps and charged sticky pad survey results provided to you, eliminated DRP migration due to ventilation alteration evolutions."

Management at the INPO Inspection Team Welcoming Meeting.

[Incline]

Attracting hot particles with some sort of positive or negative charge apparatus sounds like a pretty cool science experiment and all. But what if one sent a deconner into the contaminated area 2 or 3 times a shift with a HEPA vac and a 2" x 12" flat attachment to vacuum the CA and have one on the outside to do the same thing too? But if you have some cash thats burning a hole in your pocket then buy a walk behind floor machine like they use at the local grocery store for about $5000 and it will wet, scrub, vac, and squeegee all in one pass. Great for clean areas i think.
Mopping and massilinning is going to pick some up hot particles and push others into indentions in the concrete flooring. A vac would get them regardless of particle charge and floor surface coating plus save time, money, and frustration on R&D.
Just a thought from a lowly RP Tech.

[wlrun3@aol.com]

   This topic, the net electric charge of corrosion product contamination, and ways to use this charge for contamination control, has finally become generally recognized in our industry as having near universal applicability.
   IVVI platform accumulates troublesome levels of contamination in spite of installed bottom spray ring or manual hydrolazing...platform bottom surfaces need net negative charge to prevent net positive corrosion product accumulation.
   PCMs only 50% effective in recognizing and rejecting Radon, even with Canberra Argos Radon Rejection Software...personnel and equipment electric charge neutralization prior to RCA exit process.
   Small Article Monitor response to electrostatic adhesion of naturally occurring radionuclides on work gloves, paperwork, lanyarded/laminated badges/operator aids and hard hat/safety glasses...develop simple electrostatic charge neutralization device to replace current marginally effective practice of charge transfer by spray and wipe or confiscation of material in expectation of eventual clearance by naturally occurring radionuclide decay.

   There are many other examples.

   We have all seen the substantial wastage of time, dose and money caused by elecrostatic charge interference in contamination control efforts.

   

   

[UncaBuffalo]

     IVVI platform accumulates troublesome levels of contamination in spite of installed bottom spray ring or manual hydrolazing...platform bottom surfaces need net negative charge to prevent net positive corrosion product accumulation.

I heard "electrostatic charge" blamed for our high dose rates in the IVVI platform at WPPSS Columbia.  What a bunch of BS.  Our problem there is that they built the stupid tub with a huge amount of horizontal surfaces that can't be reached with a spray wand.

I am keeping an open mind about the whole topic, because it is definitely the flavor-of-the-day in voodoo RadCon, but...mark me "undecided" about the usefulness until someone shows me a 'solution' that works...

[wlrun3@aol.com]

   As I understand it, the factors that determine CRUD deposit locations are RCS flow restriction points, extreme flow angle deflection points, metal surface temperature differences, metal surface granularity and dissimilar metal interfaces.
   Could I be over generalizing about net electric charge as a major factor in contamination adhesion points?

[wlrun3@aol.com]

   If I used a bar magnet and a small amount of corrosion product contamination and by gamma spectroscopy determined the contamination to be overwhelmingly Co60 and found, by frisker, that the negative pole of the magnet attracted the contamination wouldn't I be able to incrementally scale up the magnetic field and incrementally increase the distance between the magnet and the contamination and come to some conclusion about what would be possible in using magnetic/electro-magnetic fields to attract/contain/ capture Co60 DRPs for the purpose of contamination control?

[HydroDave63]

 cheap and MSDS friendly smoke generators I saw in use at Rocky Flats

Ever since 2010, that would probably be MMJ wrapped in a ZigZag...

[GLW]

  If I used a bar magnet and a small amount of corrosion product contamination and by gamma spectroscopy determined the contamination to be overwhelmingly Co60 and found, by frisker, that the negative pole of the magnet attracted the contamination wouldn't I be able to incrementally scale up the magnetic field and incrementally increase the distance between the magnet and the contamination and come to some conclusion about what would be possible in using magnetic/electro-magnetic fields to attract/contain/ capture Co60 DRPs for the purpose of contamination control?

I've actually frisked magnets, there's just enough ferrous metal in a frisker probe to make frisking strong magnets really annoying,...

[wlrun3@aol.com]

Did the magnets effect on the frisker probe significantly interfere with contamination detection?

[RDTroja]

Did the magnets effect on the frisker probe significantly interfere with contamination detection?

Only the counting geometry due to changing the distance from the source to the detector... oh, and cross contamination of the detector.

[wlrun3@aol.com]

Roger,
   What have you seen in the way of efforts to use charge to attract/collect hot particles and/or eliminate/reduce radon interference?
   You have almost 40 years of RP experience by now as I recall. I was there when that photo of you in respirator and communication headset was taken.
Bill

[Rennhack]

I was there when that photo of you in respirator and communication headset was taken.

You where there when he pulled the rods on the sun? OMG!?! 

[RDTroja]

You where there when he pulled the rods on the sun? OMG!?! 

Contrary to popular belief, I did not pull the rods on the sun... That was the operator's job. I just provided the coverage.

If my memory serves me, OLD HP was the supervisor on the job (he had more experience than I did.)

[OldHP]

Contrary to popular belief, I did not pull the rods on the sun... That was the operator's job. I just provided the coverage.

If my memory serves me, OLD HP was the supervisor on the job (he had more experience than I did.)

I don't know about 'Old HP', but you're correct!  That was my second supervisors job!

[RDTroja]

Roger,
   What have you seen in the way of efforts to use charge to attract/collect hot particles and/or eliminate/reduce radon interference?
   You have almost 40 years of RP experience by now as I recall. I was there when that photo of you in respirator and communication headset was taken.
Bill

Don't make me older than I am -- in two weeks it will be a mere 38 years.  

The photo was taken in 1989 at Susquehanna at the bottom of the refuel cavity between the reactor head and the transfer canal. During that outage we had several DRPs that caused quite a bit of problems. One was found on a workers shirt pocket and I remember studies being done on the time it took to get from where he (likely) picked it up to the control point where it was found, accounting for the thickness of the shirt material for shielding and even having to count the number of cigarettes(!) in the pack in his pocket and the number of matches he had in the pack stuck in the cellophane wrapper on the cigarette pack to calculate that shielding too! They even tried to figure out who was in the elevator with him during his travels so they could gather more information on his movements. Best pencil whipping I ever witnessed.

To answer your question, I have never seen any success with using static charges favorably on DRPs. Unfavorably, yes... that is how they became known as Fleas because they jumped so well under the influence of static charges. It would make an interesting experiment, but I can't help thinking it could cause as many problems as it would solve.

As for Radon, I have seen vacuum cleaners used to remove stubbornly clingy Radon from clothing (wearing cotton helps even more) but never a static charge, that I know of. They make static charge lint removers so maybe that would be a good starting point for an experiment. I am willing to bet that most options have been tried at TMI because they are in one of the highest Radon areas in the US.

I'm just glad we didn't know about DRPs when we set off the three explosive charges in the bottom of the SG Bowl at a certain New York power plant and blew the blast cover off. I can only imagine the fun we would have had collecting them all...

[peteshonkwiler]

Don't make me older than I am -- in two weeks it will be a mere 38 years.  

I'm just glad we didn't know about DRPs when we set off the three explosive charges in the bottom of the SG Bowl ...

You always make me feel so young.  A couple of weeks and I'll hit the 3.6 decade mark.  Far better than the option...

Three charges not only wake the rookie boilermaker, but get the attention of Station
RSO types too.  I remember the tents coming off S/Gs occasionally at one of the southern plants I passed through.

[OldHP]

Don't make me older than I am -- in two weeks it will be a mere 38 years. 

I'm just glad we didn't know about DRPs when we set off the three explosive charges in the bottom of the SG Bowl at a certain New York power plant and blew the blast cover off. I can only imagine the fun we would have had collecting them all... 

Sometimes I wish it were a mere 38!   

Only 3?  I'm also glad the flea problem had not hit the boards when we were doin some major plugging (10 ea x 5)!  And not even one recordable contamination incident.

[SloGlo]

Only 3?  I'm also glad the flea problem had not hit the boards when we were doin some major plugging (10 ea x 5)!  And not even one recordable contamination incident.

that's because no body could right wearing triple gloves. 

[wlrun3@aol.com]

[wlrun3@aol.com]

Would this deionizing air knife installed above the passage way prior to the RCA exit point reduce PCEs?

[RDTroja]

Sometimes I wish it were a mere 38!   

Only 3?  I'm also glad the flea problem had not hit the boards when we were doin some major plugging (10 ea x 5)!  And not even one recordable contamination incident.

I'm not talking about 3 charges in the tubes -- I am talking about them loose in the bottom of the bowl. The equivalent of a full stick of dynamite just laying in the bottom after they fell out of the tubes. We blew a bolted-on steel blast cover across the S/G bay. When I went in to investigate and grab an air sample, my brother told me I disappeared in to the cloud that was rolling out of the channel head. Fun stuff.

No contaminations on that one, either. Of course, that was back in the 'tape-up-the-respirator' days.

[OldHP]

I'm not talking about 3 charges in the tubes

I forgot about that incident!

[Starkist]

came across this article, seems to be aligned to what you guys are discussing.

http://www.anl.gov/Media_Center/News/2010/news100225.html 

[HydroDave63]

came across this article, seems to be aligned to what you guys are discussing.

http://www.anl.gov/Media_Center/News/2010/news100225.html 

Only if the workers are soaked in water and cesium...

[Starkist]

Only if the workers are soaked in water and cesium...

Nah, just meaning the general idea of attracting charged radioisotopes. I thought it was neat anyway, not really implying its use (or lack thereof) in a nuclear plant setting.

 

 

[HydroDave63]

The conundrum would be that any combination of blown ionized air strong enough to remove the DRPs is also going to have safety warnings of  'avoid face and eyes, avoid bare skin' etc. Assuming the IH folks agree with the precautions, some of these babies could do the trick:


http://www.ccsteven.com/Static_Control/Ionizing_Blowers/ionizing_blowers.html

or

http://www.esdproducts.biz/Ionization/IonizingGuns/ionizingguns.html

[Safety Matt]

Only if the workers are soaked in water and cesium...

How could that ever happen? 

[peteshonkwiler]

Would this deionizing air knife installed above the passage way prior to the RCA exit point reduce PCEs?

I am pretty sure that using both or either of these items at the CA exit of containment would give the station CHP a cardiac condition.  I don't ever remember being told to send a hot particle airborne as a matter of decontamination.  I do remember that we were taught to tightly contain and control said particles. 

[retired nuke]

I am pretty sure that using both or either of these items at the CA exit of containment would give the station CHP a cardiac condition.  I don't ever remember being told to send a hot particle airborne as a matter of decontamination.  I do remember that we were taught to tightly contain and control said particles. 

Well.... having it inhaled will contain and control it....

[spentfuel]

I'm just glad we didn't know about DRPs when we set off the three explosive charges in the bottom of the SG Bowl at a certain New York power plant and blew the blast cover off. I can only imagine the fun we would have had collecting them all...

Jeez you are older than dirt 

From what I recall one of the plugs fell out of the tube and landed on the blast bag prior to detonation.... oops

IMHO that was prior to the invention of DRP's but that certain plant was known for having pieces of fuel lodged in various valves like a certain 800+ R/hr drain on a letdown heat exchanger.

I think DRP's actually became more prominent in the industry when our regulators started requiring utilities to fully offload the core for fuel inspections instead of just replacing the spent and doing incore reshuffles but again IMHO.

To the actual question the charges are positive and I have never seen any of the electrostatic devices work worth a hoot.  A massillen or a tacky mat roller is what Ive seen most effective.

Ill also add I have never seen one on an air sample so I would guess that instead of being blown out by an open door, the the fleas are carried out by workers and perhaps moved around a bit by airflow during PC removal.

My two cents
sf

[RDTroja]

Jeez you are older than dirt 

From what I recall one of the plugs fell out of the tube and landed on the blast bag prior to detonation.... oops

IMHO that was prior to the invention of DRP's but that certain plant was known for having pieces of fuel lodged in various valves like a certain 800+ R/hr drain on a letdown heat exchanger.

I think DRP's actually became more prominent in the industry when our regulators started requiring utilities to fully offload the core for fuel inspections instead of just replacing the spent and doing incore reshuffles but again IMHO.

To the actual question the charges are positive and I have never seen any of the electrostatic devices work worth a hoot.  A massillen or a tacky mat roller is what Ive seen most effective.

Ill also add I have never seen one on an air sample so I would guess that instead of being blown out by an open door, the the fleas are carried out by workers and perhaps moved around a bit by airflow during PC removal.

My two cents
sf

Actually, as I stated before, all three fell out (the boilermaker didn't understand what an over-center cam lock was) and the 'blast bag' was a HEPA Hose attached to a steel collar bolted to the manway. The whole thing was blown off the S/G, toward the S/G bay wall and down to the floor. Very loud. That was how we knew something was wrong before we looked. Everyone was wearing a Full Face Respirator and all you could see in the facepieces were eyes. Fairly comical looking back on it... not so much at the time.

I agree that moving the fuel around extraneously probably contributed to the DRP problem, but I also think longer fuel cycles didn't help either.

BTW, I am only older than some dirt.