[ RadSafe ] [EXTERNAL] Radon progeny in CNG vehicles gas tanks

Wasiolek, Maryla mwasiol at sandia.gov
Wed Apr 16 17:43:21 CDT 2014


If you have radon and its decay products in the gas, you are not going to get much Pb-210 out of that. Let's assume that you have 1 Bq of Rn-222 in equilibrium with its decay products and that the Rn-222 is unsupported (i.e., there is no Ra-226 to produce more Rn-222). The decay of that 1 Bq of Rn-222 and the decay products will ultimately produce about 4.8E+5 atoms of Pb-210, which is equivalent to about 4.7E-4 Bq. You can use this example to calculate the amount of Pb-210 from the actual concentrations of Rn-222 and its decay products in your gas, as long as they are initially in equilibrium, but it is quite easy to do analogous calculations if they are not. If you want to know how I got these numbers, you can contact me directly.

Maryla Wasiolek
mwasiol at sandia.gov

-----Original Message-----
From: radsafe-bounces at health.phys.iit.edu [mailto:radsafe-bounces at health.phys.iit.edu] On Behalf Of John Hultquist
Sent: Wednesday, April 16, 2014 3:59 PM
To: radsafe at health.phys.iit.edu
Subject: [EXTERNAL] [ RadSafe ] Radon progeny in CNG vehicles gas tanks

I could use help in exploring a question with fellow radsafers in knowing if bi-fuel or CNG vehicles are triggering radiation alarms because of radon and its decay products as a natural contaminant of the natural gas.

I understand that hydrocarbons from the Dakotas and Pennsylvania are being produced with radon as a natural contaminant.

I am going to speculate that as vehicles with CNG tanks age, the lead-210 from any natural gas with radon is going to build up (Pb-210 half-life is
22.26 years)in the inside wall of the tank.   Maybe the radiations from
Pb-210 or Bi-210 will cause radiation detectors across the country to alarm.

Any insight to this issue would be appreciated.

John Hultquist,
Utah Division of Radiation Control
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