Sr/Y-90

[Jack_Earley@RL.GOV]

Two of the many responses I've received are shown below. At this point,

we're not doing chemical extractions (we'll save that for the Pu inventory

balance and disposal characterization). This is old fuel; it's been in

storage for over 25 years; the primary component is Cs-137. So this is not

pure Sr-90, if that's been a point of confusion.





<<I think we've got Sr-90/Y-90 confused with Y-90.  If you do a chemical

extraction of Y-90 to obtain pure Y-90, its all beta.  I think the Sr-90

goes to Y-90m to Y-90.  >>





<<if Sr-90 does NOT decay to Y-90m, then where in the world does the Y-90m

come from?  Out of thin air? I have also watched the RADSAFE e-mail traffic

on this issue.  Many folks appear to be using older Table of Isotopes

versions which may have either been wrong on this issue or misleading and

could have been updated/corrected in later iterations of the Table of

Isotopes.  By the way, the absolute latest "Table of Isotopes" is the 8th

Edition, Firestone, Shirley, Editors with Baglin, Chu, and Zipkin as

Assistant Editors, Wiley-Interscience 1996; ISBN 0-471-14918-7.  I checked

this Table of Isotopes--it appears to say essentially the same thing as the

1986 Table of Isotopes, except that the percent of time of the isomeric

transition of Y-90m is specified as 99.9982% instead of the 1986 percent of

99.9979% and other minor changes in energy level values, etc.>>





Does this affect anyone's responses?



Jack Earley

Radiological Engineer

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