[ RadSafe ] Re: Half-life

chris.hofmeyr at webmail.co.za chris.hofmeyr at webmail.co.za
Sun Dec 14 02:49:43 CST 2008

I believe the two organisations approach the problem differently and
therefore come to different conclusions.  The NRC sees it as a question of
waste which is reduced by a factor 1000 after 10 halflives (600 days) and
in a landfill the exposure potential would be almost negligible.  The FDA
deals mainly with nuclear medicine isotopes which patients carry around in
their bodies, where physical and biological halflife would combine to
determine public exposure potential.  In that case a few months is a long

Chris Hofmeyr
chris.hofmeyr at webmail.co.za

> Colleagues:
> I have a question that I'm sure one of you can answer.  It is:  what is
> considered a 'short-lived' radionuclide?  The US Nuclear Reagurlatory
> Commission considers that any radionuclide under 60 days can be decayed to
> background and then assigned to normal 'waste'.  The US Food and Drug
> administration considers any radionuclide of ~55-59 days as long lived.
> Who is correct or are both???
> Ed Baratta
> edmond0033 at comcast.net
> ___________________________

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