[ RadSafe ] Half-life nonsense

Tue Jul 24 12:55:36 CDT 2012

Jerry,
The half life of a lone neutron is 10.2 minutes. Perhaps you were thinking of the proton???

Regards,
John E. Dixon

-----Original Message-----
From: radsafe-bounces at health.phys.iit.edu [mailto:radsafe-bounces at health.phys.iit.edu] On Behalf Of Jerry Cohen
Sent: Monday, July 16, 2012 7:05 PM
To: The International Radiation Protection (Health Physics) Mailing List
Subject: Re: [ RadSafe ] Half-life nonsense

I'm afraid I must disagree. High vs. low-level radioactivity is determined according to its radioactivity per unit mass or volume (eg. Ci/gm) regardless of its longevity. Half-life has nothing to do with it.

In a sense, essentially everything may be considered radioactive since the neutron itself is estimated to decay with a half-life of about 10E31 years. 

This sounds like the difference between low level radioactivity and high level radioactivity.

On 7/16/2012 9:29 AM, Brennan, Mike (DOH) wrote:
> I deal (mostly) with environmental rad, but I also talk with people who use rad 
>in the medical field.  For the medical folks, "long half-life" is anything more 
>than about 100 days.  For me, Long half-life is when it is more convenient to 
>write it in scientific notation.
>
> -----Original Message-----
> From: radsafe-bounces at health.phys.iit.edu 
>[mailto:radsafe-bounces at health.phys.iit.edu] On Behalf Of Jerry Cohen
> Sent: Saturday, July 14, 2012 1:09 PM
> To: The International Radiation Protection (Health Physics) Mailing List
> Subject: Re: [ RadSafe ] Half-life nonsense
>
> Lets see if I understand this correcly---If it is man-made, it is bad (ie.
> hazardous)
> but naturally occuring is OK. Right???
> By that standard, aspirin is a poison, and hemlock is OK
>
> At the HPS meeting in 1980, I gave a paper intended to address the longevity
> nonsense by proposing a change in definition. We proposed that:
>
> Radionuclides with a half-life less than one million years be considered
> radioactive,
>
> Radionuclides with a half-lifes between one million and one trillion years are
> radiopassive,and
>
> Those with half lives greater than a trillion years (eg. I-129) are
> radioquiescent (ie. stable elements)
>
> Somehow, the idea never caught on.
>
>
>
>
>
> ________________________________
> From: John R Johnson <idiasjrj at gmail.com>
> To: Jerry Cohen <jjcohen at prodigy.net>; The International Radiation Protection
> (Health Physics) Mailing List <radsafe at health.phys.iit.edu>
> Sent: Fri, July 13, 2012 4:22:42 PM
> Subject: Re: [ RadSafe ] Texas LLRW Site
>
> Jerry
>
> Isn't it because it does not occur in "nature". If I-129 is present it must
> be "man made" and likely an indication of other isotopes being made.
> John
> On Fri, Jul 13, 2012 at 3:38 PM, Jerry Cohen <jjc105 at yahoo.com> wrote:
>
>>
>> I wonder what makes I-129 a "radionuclide of interest". Its exceedingly
>> long
>> half-life makes it essentially a stable element, no different than the
>> stable
>> iodine that occurs naturally in most soils.
>>
>> Jerry Cohen
>>
>>
>> Dear Radsafe,
>>
>>      From:    _jpreisig at aol.com_ (mailto:jpreisig at aol.com)    .
>>
>>
>>      Hope you are all doing well.  HP  abstracts for the HP Society
>> Meeting in Sacramento,
>> California are out now, as a supplement to Health Physics magazine.
>> Always interesting
>> reading.  One item is on DU by Bob Cherry.
>>
>>      Operational Radiation Safety (another HPS journal)  has an article on
>> Decommissioning of the
>> Brookhaven Lab High Flux Beam reactor.  Fuel and spent fuel are  gone.
>> Heavy Water is gone.
>> Interesting reading.  I guess that's one way of totally stopping  the
>> tritium leak source term.
>> The offending leaking fuel storage pool was drained.  Goodbye.  Wonder
>> what they'll do with the
>> Brookhaven Medical Research Reactor.  I don't think there was anything
>> wrong with it..
>>
>>      There's an abstract on the new Texas LLRW (Low Level  Radioactive
>> Waste) facility and some
>> modeling they did.  The radionuclides of interest are C-14, Tc-99,  I-129,
>> possibly among others.
>> I guess tritium is not that big a deal in such a facility, due to its short
>> half-life.  These radionuclides
>> are particularly mobile in the groundwater environment, as referred to in
>> my earlier RADSAFE
>> postings.  These Texas folks did some computer modelling and describe  what
>> they did.  Wonder why
>> they didn't just use Femwater-BLT (Suen and Sullivan???),  Lewater, Lewaste
>> or similar computer
>> codes.  Last I heard, Femwater-BLT was available for use on a personal
>> computer.  It is or was
>> available for a fee from the RSICC, the Radiation Shielding Information
>> Center at Oak Ridge
>> National Laboratory (USA).  Other Radiation computer codes are  available.
>> Finally, if you see a computer
>> code you are interested in, you can search it out on the internet, and then
>> email the original
>> programmers/designers for information on how to obtain such a computer
>> code.  No big deal.
>>
>>      These newfangled small, modular reactors are also  addressed in an
>> abstract.  Sounds like
>> some of them will be deployed by the TVA, in the Tennessee Valley.
>> Newfangled nuclear
>> electricity for people/homes/businesses previously not on the electricity
>> grid.
>>
>>      NJ Nuke plants and workers, thanks for the 50% of the  electricity (in
>> NJ) that you are providing to
>> air condition part of my home this summer!!!!  Take Care...
>>
>>      Regards,    Joseph R. (Joe) Preisig,  PhD
>>
>>
>>
>>
>>
>>
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>>
>> ________________________________
>>
>> From: "JPreisig at aol.com" <JPreisig at aol.com>
>> To: radsafe at health.phys.iit.edu
>> Sent: Thu, July 12, 2012 8:44:56 PM
>> Subject: [ RadSafe ] Texas LLRW Site
>> _______________________________________________
>> You are currently subscribed to the RadSafe mailing list
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>> Before posting a message to RadSafe be sure to have read and understood
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________________________________

From: The Wilsons <pnwnatives at gmail.com>
To: radsafe at health.phys.iit.edu
Sent: Mon, July 16, 2012 2:16:01 PM
Subject: Re: [ RadSafe ] Half-life nonsense
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