RE: Estimation of the activity of uranyl nitrate

["Baratta, Edmond J" <EBARATTA@ORA.FDA.GOV>]

Hi:

	The uranium nitrate (an oxidizer) contains uranium that was
originally separated (purified)
	from other elements.  However the first decay product of the U-238
is Th-234 and is a beta 	emitter and has a 24.1 d half-life.  This
decays to Pa-234m and then Pa-234, and has some 	low abundance
X-rays.  These are short-lived 1.14m and 6.7 H, respectively.  Thence to 
	U-234, with a 2.67 E05 y half-life.  U-234 decays to Th-230 with an
8.0 E04 y half-life.
	Both are essentially alpha-emitters.  U-235 decays Th-231, beta
emitter which decays
	to Pa-231 with a 3.43 E05 y half-life.  The U-235 and Pa-231 are
essentially alpha emitters.
	You can calculate the uranium activity and for the three in
equilibrium we come out for one
	gram it is 0.398 microcuries (or 3.7 E04 Bq/microcurie).  It is
listed as a "low specific
	activity".  The hazard is mainly as the chemical and as an
oxidizer".

Ed Baratta  
-----Original Message-----
From: JOHN LAM [mailto:lamhc@hkusua.hku.hk]
Sent: Monday, February 26, 2001 12:29 PM
To: Multiple recipients of list
Subject: Estimation of the activity of uranyl nitrate


Hi,
would anybody provide me information on the following?
One of our pathology laboratories had held some few tens of grams of uranyl
nitrate, which I think was supposed to be used as chemical stain purpose.
That vial did not have any kind of radiation signage label on its surface
but only a danger sign instead. 
When a beta-gamma contamination monitor is held near it, some radiations
are detected, however a GM gamma probe shows no significant reading at all.
Would there be any U235 or U238 ? Ra226 ? Po218 ? Po214
What isotopes could possibly be left in the vial if this vial have already
been stored for more than ten years long? 
What proportions of isotopes are there and what proportions of beta or
gamma emissions could be found too?








>Your feedback is appreciated.
>
>John Lam
>Medical Physicist
>Eastern Hospital, Hong Kong



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