[ RadSafe ] Airborne radioactivity

Tue Apr 10 16:31:15 CDT 2007

Jack et al: 
As any former Refuel floor RP Tech or Refuel Operator could also say...  While working around various fuel pools and vessels during refuel outages I've observed ion chamber deflections from bubbles (xenon, krypton, etc.) as they break the surface. Such occurences would typically be monitored by local RP technicians, especially if there were any fuel pin integrity compromises during the previous fuel cycle. I've also observed migration (creeping) of contaminants as a function of heated fuel-pool water when chillers were taken out of service for extended periods of time, and so forth.  So.  There's nothing so extraordinary about what Jack is indicating.  Without knowing the source, I suppose the problem I would be trying to resolve is "what is the worst-case scenario" for the work activity.  Since there does not appear to be a reliable formula for predicting "cause and effect" with respect to work activity variables, (rate of material ablation or release of activity, water-depth, surface area, ventilation turnover, temp, etc.) versus predictions of activity (whatever the source material is...) concentrations at the surface (effect) then a logical course of action would seem to be to conduct empirical field trials under positive controlled conditions using minimal quantities to observe and plot "cause - effect" using condtions that would be similar to those during work execution.  Who knows, you might even be able to write for a grant to do it!

Neil Keeney 

-----Original Message-----
From: idias at interchange.ubc.ca
To: Jack_N_Earley at RL.gov; hacrad at comcast.net; radsafe at radlab.nl
Sent: Tue, 10 Apr 2007 1:31 PM
Subject: Re: [ RadSafe ] Airborne radioactivity

Jack 

Was the radioactivity in the ANL situation from the water, or from Th-Nat in the welding rods? 

John 
*************** 
John R Johnson, PhD 
CEO, IDIAS, Inc. 
Vancouver, B. C. 
Canada 
(604) 222-9840 
idias at interchange.ubc.ca 

----- Original Message ----- From: "Earley, Jack N" <Jack_N_Earley at RL.gov> 
To: "Harold Careway" <hacrad at comcast.net>; <radsafe at radlab.nl> 
Sent: Tuesday, April 10, 2007 12:00 PM 
Subject: RE: [ RadSafe ] Airborne radioactivity 

Thanks for the clarification, Hal. Another scenario would be arc welding under water in a radioactive basin/fuel pool. ANL had some uptakes a few years back from this activity that was unanticipated from initial air samples. 

Jack Earley 
Health Physicist 
509.372.9532 

-----Original Message----- 
From: radsafe-bounces at radlab.nl [mailto:radsafe-bounces at radlab.nl] On Behalf Of Harold Careway 
Sent: Tuesday, April 10, 2007 10:04 AM 
To: radsafe at radlab.nl 
Subject: [ RadSafe ] Airborne radioactivity 

Franz, 
I'm guessing I may know what is going on here but can't really help. Given a line carrying a radioactive gas, if that line breaks under water the gases can be released to the water and depending upon flow rate, gas content, temperature of the gas and water, and water depth; the resultant bubbles can be scrubbed in the water resulting in various levels of contamination in the air above the water as well as in the water. Up to the point of entrainment in the water, the process is strictly physical and non-chemical. Once the material is in the water, chemical variations compound the analysis. The solution is non-trivial (you need elliptic integrals) and though the NRC has done significant work in this area, the only really accurate and valid work 
I've ever seen was done by GE Nuclear and is strictly proprietary. 

To find what is available you can start with NUREG/CR-5901, "A Simplified Model of Aerosol Scrubbing by a Water Pool Overlying Core Debris Interacting With Concrete", then go onto Google and look for "pool scrubbing" and "DECON". 

Frankly, trying to do a realistic calculation or model is extremely really, really hard to do. I know of no rules and thumb and would be interested if anyone else does. 

Hal Careway 
San Jose, CA 
GE Retired. 

-----Original Message----- 
>From Franz Schönhofer 
Sent: Monday, April 09, 2007 4:38 PM 

Dear Health Physicist, 

This is the first of two messages today, which request from RADSAFErs some information without giving even the slightest details. As a Health Physicist you should know, that there are thousands of different radionuclides, which behave differently, coming in different chemical forms, have different solubility etc. etc. Do you want to know the radon level to be expected...... bla, bla, bla. 

Not being a native speaker I regard "air line" being rather in the context of "DELTA", "Austrian Airlines", "Lufthansa", "Iberia" etc. 

I hope you can explain, what you really want. 

Franz 

Franz Schoenhofer, PhD 
MinRat i.R. 
Habicherg. 31/7 
A-1160 Wien/Vienna 
AUSTRIA 

>From Earley, Jack N 

Does anyone have any calculations or guidelines for determining the resulting airborne radioactivity levels from an air line breaking under water, relative to the air flow rate (or from performing an air sparge in radioactive water)? 

Jack Earley 
Health Physicist 
509.372.9532 

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