[ RadSafe ] Half-lives

[Cary Renquist]

As Mike described it is somewhat subjective.

One could look at some of the places where half-life gets referenced in regs...
Very short: < 90/120 days (decay in storage regs/guides)
Short: < 5 years (waste disposal regs)

I can't think of any reg references for medium or long...
My subjective version:
Medium: 5 < T > 30/40 years
Medium-Long: 30 < T > 250 years
Long: > 250 years

Cary

-----Original Message-----
From: radsafe-bounces at radlab.nl on behalf of Brennan, Mike  (DOH)
Sent: Fri 19-Sep-08 16:17
To: radsafe at radlab.nl
Subject: RE: [ RadSafe ] Half-lives
 
It depends on the field you are working in.  When I talk to medical
people, "long" is anything with a half-life greater than 90 days.
"Short" is measured in minutes or several hours.  When I do radon work,
"short" is in minutes, "long" is Pb-210 (22 years).  When I work in
environmental radiation, Co-60 (five years) is short, Cs-137 (about 30
years) is "medium".  "Long" is anything that is easier to express in
scientific notation.

-----Original Message-----
From: radsafe-bounces at radlab.nl [mailto:radsafe-bounces at radlab.nl] On
Behalf Of Steven Dapra
Sent: Friday, September 19, 2008 4:05 PM
To: radsafe at radlab.nl
Subject: [ RadSafe ] Half-lives

Sept. 19, 2008

	Is there a convention for dividing half-lives into groups for
very long (such as U-238), long, medium, short, and very short?  If
there is, what are the dividing points for the various lengths of time?

Steven Dapra
sjd at swcp.com

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