[ RadSafe ] Short Half Life = Pornography? or: Relativity Confuses Me.

Geo>K0FF GEOelectronics at netscape.com
Sun Dec 14 10:31:13 CST 2008

"Message: 10
Date: Sat, 13 Dec 2008 11:46:59 -0500
From: "Edmond Baratta" <edmond0033 at comcast.net>
Subject: [ RadSafe ] Re:  Half-life
To: <radsafe at radlab.nl>
Message-ID: <130B2AC659074D5996F1F2B3562D4691 at OWNER84J1T8A8N>
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I have a question that I'm sure one of you can answer.  It is:  what is considered a 'short-lived' radionuclide? "


The NRC GLOSSARY defines half life as:
Half-life The time in which one half of the atoms of a particular radioactive substance disintegrate into another nuclear form. Measured half-lives vary from millionths of a second to billions of years. Also called physical or radiological half-life. 

Neither the NRC glossary or the Nucleonics Dictionary define "short", however 10CFR 61.55 is attempting to classify waste as short or long and some attempt is being made to improve those definitions, at least by listing them in a table.

Webster defines "short " as: 1 a: having little length b: not tall or high : low2 a: not extended in time : brief <a short vacation> 

According to this definition, all vacations are short and all lectures are long. 

Everyone seems to know what the "short half" is, especially when referring to turkey wishbones. 

In http://www.nrc.gov/reading-rm/doc-collections/nuregs/brochures/br0216/

radioiodine 131 (8 days) is called a short half lived nuclide, while Pu-241 at 6800 years is called "long". 

Yet here is an NRC document referring to Am-241 (432 years) and Np-232 ( 2 million years) both as short:


The US Supreme Court says that they don't know what pornography is, but they know it when they see it. Short half life seems to be similar to pornography. 

I am 5 foot six. To myself  I am neither short or tall. To my wife who is 5 foot 2, I am tall. To my son who is 6 foot 2, I am short. 

In the Masai tribe of Kenya, I am short and come up to their belly buttons. In Ireland where I am from, I could be a basket ball player. Girls in the Netherlands are quite tall, and I am about beast high to them. Many Irishmen like to visit the Netherlands. Perhaps there is a connection.

Go figure

George Dowell

New London Nucleonics Lab

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