DRP content

[atomicarcheologist]

I just surveyed a DRP that came to where I'm working from DC Cook.  Since I recently started here, I figured I would use this to do my own QC on this site's instrumentation.  This DRP came in at 1 mCi.   Based on site specific MFP, what would one expect the dose rate to be, with a RO2?

[butterflyfrills]

what hell is he talking drp mip pdq //

[Rennhack]

what hell is he talking drp mip pdq //

Nice first post.

DRP = Discreet Radioactive Particle.

[atomicarcheologist]

I just surveyed a DRP that came to where I'm working from DC Cook. 

Perhaps I misused some terminology.  I'm talking about a Discrete Radiological Particle, ala Hot Particle.  Marssim's referenced site was about gauges and classes (Nuclear Gauge Training & Resource Center 
The Official On-Line Training Website of the Portable Nuclear/Moisture Density Gauge Industry, featuring Fully Accepted On-Line/Internet Safety and HAZMAT Training for Troxler®, CPN®, Humboldt®, Seaman® and InstroTek® Gauges).  I would like an estimated dose rate with an RO2 on a 1 mCi particle from DC Cook.

[Rennhack]

I would like an estimated dose rate with an RO2 on a 1 mCi particle from DC Cook.

1mCi of what?  Co-60, Cs-137, Sr-90, U235?

How about you put it in your Gamma Spec, and tell us what it is.  And... You want on contact, right?

[atomicarcheologist]

 Based on site specific MFP, what would one expect the dose rate to be, with a RO2?

I have the survey, that's not my query on this board.  I'm looking for an expected contact dose, based on DC Cook site specific current MFP inventory. 
How do I know it came from there?  The truck driver said it did.  Duh!

[HenryBlack]

Did you notify the plant and ask them. They are the ones that will be able to give you that info better than anyone here. They will most probably send someone to your site to help you if they think it came from them. It seems to me that they wouldn't let a DRP leave site on a truck. unless it was mxed in some waste stream that was contained when it left. So was it found loose in the truck or on the outside or  on PC's to be laundered, or where?

[Marlin]

   What I get is that you are looking for the true contact dose rate as opposed to the indicated dose rate. I would think that your rad engineers or in plant Health Physicist would have charts on hand for that kind of thing or know where to find or calculate this. If you are looking for the basis for the document you are currently using in plant I would just ask these same people who probably generated it.

[atomicarcheologist]

In the past, sites have been wrongly accused of sending RAM presents to other licensees.

I never said it was sent erroneously, maliciously, or with any other intent other than honorable.

Having said that, let me also say that I can accept an answer of "I don't know" to my original query RE: anticipated dose for instrument QC concerns.

[atomicarcheologist]

your avatar put me in the assume mode (the whole dirt lurcher title thingy),

I'm thinking I may have to change that, now that I'm out of the trenches...

[TENN-1]

Atomic,  Reading through the thread, I don't see where your original question was answered.  PM me and I will put you in touch with folks at Cook who might be able to provide the data you seek?

[atomicarcheologist]

TENN-1
It's OK.  I'm past dealing with the DRPs from DC Cook, onto other projects.  I was thinking that this might not be too much of a problem for the vast intelligencia which gathers here.  A quick answer was all I was looking for, as I was looking to do a little personal QC on this site's equipment.  It's not that I think there is a problem with the equipment, it's just something I like to do when I am new, bored, and getting bounced around.  No problemo.

Marsimm
A hundred and sixty eight hours?!?  Dang, what are you going to do, disassemble the DRP?  Does this include putting it back together, and would you supply the gluon needed?

[HydroDave63]

Sure, we'll throw in the gluon gratis,...

Now, Marssim, be sure when you are mixing that gluon, which can be a little viscous and condensed in ultra-cold weather (I think they call that a Bose-Einstein condensate), that you are sure to dilute that gluon with some of Maxwell's "Luminiferous Ether"

[JsonD13]

Well assuming you are "on contact" with the RO-2 (~1 cm since you dont want to touch the particle to the detector), and assuming its Co-60 (probably overestimation of energy), my guess would be if you still had 1mCi, it would overrange the RO-2 at just shy of 13 REM/hr....just my SWAG though since you didn't provide specifics like what nuclides (even if you provide a plant it came from doesnt mean we know what's in it), when the activity was measured (to decay correct), etc.....

If your'e looking more for like a plant mix, I would assume closer to 1 MeV gamma energy (I don't work at a PWR though so I'm not that knowledgable on what they have as an average mix), and roughly divide the dose by 2.5 (total gamma energy for Co-60 rounding yield for both gammas to 100%), which would give around 5 REM/hr.

Oh yeah, that's closed window.

I'd say your instrument would be good if you were within 20% of scale ;-).

Did that help?

[UncaBuffalo]

Well assuming you are "on contact" with the RO-2 (~1 cm since you dont want to touch the particle to the detector), and assuming its Co-60 (probably overestimation of energy), my guess would be if you still had 1mCi, it would overrange the RO-2 at just shy of 13 REM/hr....just my SWAG though since you didn't provide specifics like what nuclides (even if you provide a plant it came from doesnt mean we know what's in it), when the activity was measured (to decay correct), etc.....

If your'e looking more for like a plant mix, I would assume closer to 1 MeV gamma energy (I don't work at a PWR though so I'm not that knowledgable on what they have as an average mix), and roughly divide the dose by 2.5 (total gamma energy for Co-60 rounding yield for both gammas to 100%), which would give around 5 REM/hr.

Oh yeah, that's closed window.

I'd say your instrument would be good if you were within 20% of scale ;-).

Did that help?

Are you taking size-of-source versus size-of-detector into account?  

I get similar numbers just eyeballing it as a 6CEN & distance-to-source problem, but an RO2 is a HUGE ion chamber, so will WAY under-respond when put on contact with a point source...




Modified to focus on: taking a contact reading on a DRP with an RO2 doesn't make sense.

[atomicarcheologist]

I get similar numbers just eyeballing it as a 6CEN

What "E" are you using?

[UncaBuffalo]

What "E" are you using?

JsonD's

If your'e looking more for like a plant mix, I would assume closer to 1 MeV gamma energy (I don't work at a PWR though so I'm not that knowledgable on what they have as an average mix), and roughly divide the dose by 2.5 (total gamma energy for Co-60 rounding yield for both gammas to 100%), which would give around 5 REM/hr.

Oh, by the way...what kind of numbers did you get when you did your receipt survey?

What I get is that you are looking for the true contact dose rate as opposed to the indicated dose rate. I would think that your rad engineers or in plant Health Physicist would have charts on hand for that kind of thing or know where to find or calculate this. If you are looking for the basis for the document you are currently using in plant I would just ask these same people who probably generated it.

Marlin (as usual) had the RIGHT answer to this question:  The indicated contact dose rate is NOT the true contact dose rate.   (....and probably isn't ALARA!)

If you really want to check whether your RO2 is working and all you have is this DRP and you can figure out a legitimate 'E' to put into your 6CEN and you keep in mind that true contact dose rate is horrendous (and protect yourself from said dose) and on and on and on...then you probably could figure out a reasonable one foot reading that it might make sense to try to measure with an RO2...but...make sure you use some of HydroDave's "Luminiferous Ether".  

[UncaBuffalo]

C'mon Unc, geeeeez,....

If you're RO-2 was calibrated to the appropriate ANSI / ISO / etcetera standard, and it is still source checking within specification on all ranges, your RO-2 is working as designed ans as intended.

Perhaps it is not the best tool for the details of the inquiry, but that is not the tools fault.

Look at my post...I did use the ' '...but...to answer your post:

The way I read it:

I just surveyed a DRP that came to where I'm working from DC Cook.  Since I recently started here, I figured I would use this to do my own QC on this site's instrumentation.  This DRP came in at 1 mCi.   Based on site specific MFP, what would one expect the dose rate to be, with a RO2?

1.  The OP isn't sure whether his instrument is calibrated correctly.

and

2.  Doesn't have a real source.

Yes?  No?




(I only responded to JsonD because he seemed to be assuming the RO2 would give a +/- 20% of a theoretical dose rate at contact...and that is a very un-safe assumption.)

[UncaBuffalo]

My bad, I figured the winky guy was for the ether reference.

I'm pretty sure the +/- 20% is straight out of Eberlines accuracy specs for the full range of energies measured by the RO-2 doorstop device.

                           ;-)

For a dose rate (ie. uniform field, not DRP) that an RO2 is designed to measure, yes, I agree +/- 20% is standard.  

The point I am trying to make is that the RO2 will NOT read within 20% of the TRUE contact reading.  I vaguely remember correction factors of up to TIMES 250 at some plants, depending on whether the DRP was activation product, MFP, or...?  

[atomicarcheologist]

Oh, by the way...what kind of numbers did you get when you did your receipt surv

If I were to tell you my number, how will that help answer my query?  However, I will allow that my use of the RO2 was mandated by my other meter being off-scale.

[UncaBuffalo]

If I were to tell you my number, how will that help answer my query?  However, I will allow that my use of the RO2 was mandated by my other meter being off-scale.

Your contact reading is probably wrong, but your one foot reading is close to right.  We can come up with a reasonable estimate of 'EN' crunching it thru a 6CEN.  (Yes, I know that we might have to do some guesswork about how it was packaged, if you did NOT open the package...I'm still not sure if this thing was meant to be buried, or...?)

We could also take your one foot reading and run it through an inverse square to estimate a true contact.  (If you opened the package?)

And, if you still cared at that point, you could compare the true to the observed and have a correction factor for the RO2.

And, you could crunch the same formulas using the info from your other meter, if you can remember what distance you went off-scale at...?

[JsonD13]

oh yeah, this is just an exercise in splitting hairs with a jackhammer at this point,...

we need a higher order of tool(s) (HPGe and others) to do this scenario any justice,.....

Considering the efficiency of an HPGe, I think we should probably go with a 4pi NaI, hooked up to a MCA.

How many hairs did I get there?

Jason

[HydroDave63]