Charges on Hot Particles

[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?