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Offline dandelion742

Noble Gas grab sample size
« on: Jan 17, 2014, 04:18 »
Hello, I am a chemistry tech working at one of the nuke plants in Taiwan.

 In our plant we grab Noble Gas at sampling skids where gaseous effluent are collected from releasing points.  

The sampling container we have used for years is a Marinelli-style 20 Liter plastic box with petcocks, and it is heavy and NOT easy-to-carry.
 
I always wanna change to the commercially avaliable 4L Marinelli gas-tight container.

But I wonder if 4L is big enough to meet regulatory required LLD,1 x 10-4 uCi/ml, when 40% germanium detector is used and counting time is limited to about 10 min ?

What do you use for Noble Gas sampling?

Thanks for your sharing information.
« Last Edit: Jan 20, 2014, 10:44 by dandelion742 »

Offline Imaginos

Re: Noble Gas grab sample size
« Reply #1 on: Jan 17, 2014, 05:43 »
1 liter (1220 cc) Marinelli with Swagelok quick-disconnect fittings for the continuous release sample points; we can meet the LLDs with a 30 minute count time.
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Offline SloGlo

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Re: Noble Gas grab sample size
« Reply #2 on: Jan 18, 2014, 10:14 »
Yore problem is with mass or time? That counter's chamber should handle whatever volume sew aye am thinking the lab schedule is too tite two alter time frames. Oar is their a programing challenge?
quando omni flunkus moritati

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Offline dandelion742

Re: Noble Gas grab sample size
« Reply #3 on: Jan 19, 2014, 08:18 »
Thank you for your reply.

Since our Lab have large sample loads with only two gamma spectroscopy systems and cannot tolerate counting time longer than 10 ~15min, we try to enlarge our sample mass as possible as we can.
« Last Edit: Jan 20, 2014, 02:50 by dandelion742 »

milo124

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Re: Noble Gas grab sample size
« Reply #4 on: Jan 20, 2014, 12:06 »
A junior HP tech running around with an open bag to trap the gas?

Offline dandelion742

Re: Noble Gas grab sample size
« Reply #5 on: Jan 20, 2014, 06:26 »
 ;D haha, I am a junior with open mind seeking for the best practice on grabing gas sample from you experienced senior.

Offline SloGlo

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Re: Noble Gas grab sample size
« Reply #6 on: Jan 22, 2014, 01:46 »

But I wonder if 4L is big enough to meet regulatory required LLD,1 x 10-4 uCi/ml, when 40% germanium detector is used and counting time is limited to about 10 min ?

if your lld is regulated then you need to contact your instrument supplier for more sensitivity as lld is a measure of minimum counting to satistical acceptable efficiency.
quando omni flunkus moritati

dubble eye, dubble yew, dubble aye!

dew the best ya kin, wit watt ya have, ware yinze are!

chuckdhuff

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Re: Noble Gas grab sample size
« Reply #7 on: Jan 27, 2014, 11:31 »
if your lld is regulated then you need to contact your instrument supplier for more sensitivity as lld is a measure of minimum counting to satistical acceptable efficiency.

Only one misspelled word, and reading your post didn't make my head hurt. Did you use this? https://www.hookedonphonics.com/

Offline SloGlo

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Re: Noble Gas grab sample size
« Reply #8 on: Jan 27, 2014, 12:16 »
Only one misspelled word, and reading your post didn't make my head hurt. Did you use this? https://www.hookedonphonics.com/
hail know! eye took a simplistic approach to onscreen persona. It was write after aye attended yet an udder educational enlightenment effort. Deepest apologies for that miss spelling, totally inadvertent.  ;)
quando omni flunkus moritati

dubble eye, dubble yew, dubble aye!

dew the best ya kin, wit watt ya have, ware yinze are!

Offline MGH

Re: Noble Gas grab sample size
« Reply #9 on: Feb 02, 2014, 02:09 »
Dear Junior Tech...take clear plastic bag...the bigger the better...draw a propeller symbol on it...now open the top and run around the plant in the vicinity of where you think you need to take a sample...make five laps around the closest component...close bag and seal with J-seal. Post photos or video on line and provide the link...senior techs will provide the sample results...no further analysis needed. Thanks

Offline HydroDave63

Re: Noble Gas grab sample size
« Reply #10 on: Feb 02, 2014, 02:22 »
;D haha, I am a junior with open mind seeking for the best practice on grabing gas sample from you, experienced senior.

When sampling gas from an experienced senior, usually Depends with a tight duct tape seal along the legs and sample point works best!  ;)

Offline SloGlo

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Re: Noble Gas grab sample size
« Reply #11 on: Feb 02, 2014, 05:17 »
When sampling gas from an experienced senior, usually Depends with a tight duct tape seal along the legs and sample point works best!  ;)
as opposed two sampling from an inexperienced senior oar an eager junior, when won uses an inserted inverted flexible sample container.
quando omni flunkus moritati

dubble eye, dubble yew, dubble aye!

dew the best ya kin, wit watt ya have, ware yinze are!

 


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