Re: Sr/Y-90

["Franz Schoenhofer" <franz.schoenhofer@CHELLO.AT>]

-----Ursprüngliche Nachricht-----

Von: Vincent A King/KINGVA/CC01/INEEL/US <KINGVA@INEL.GOV>

An: radsafe@list.vanderbilt.edu <radsafe@list.vanderbilt.edu>

Datum: Mittwoch, 13. Februar 2002 21:40

Betreff: Re: Sr/Y-90





>

>In answer to the statement below, a very old reference I have

>(Scintillation Spectrometry, 2nd edition, R.L. Heath, 1964!) lists a

>production mechanism as  Zr-90(n,p)Y-90m. It could also be a direct product

>from fission (i.e., not indirect through Sr).  I do know that the existance

>of the metastable state doesn't necessarily mean that Sr-90 decays by that

>pathway to any significant degree.  I'm still pretty sure that there are

>NOT two easily detectable gammas emitted for each Sr-90 beta decay,

>otherwise detecting and quantifying Sr-90 would be a much easier job than

>it is for people who must do it routinely.

>

>I don't have immediate access to the latest reference mentioned, but it

>would be rather odd for an error of that magnitude to have been printed and

>repeated in all the references I do have (Rad Health handbook, Kocher's

>Radioactive Decay Data Tables, etc.) which all say Sr-90 decays essentially

>100% to Y-90, not Y-90m.

>

>I'm surprised some real heavyweight expert has not jumped into the

>discussion by now to put us all to shame.





------------------------------



Hi, Vincent, nice to hear your "voice" again!



Yes,   I T   I S   A   S H A M E  !!!!



I have worked for - yes I can say it - decades with methods to determine

Sr-90 in the environment. In my typical European manner I regard myself of

being not "the" expert, but a member of the experts on this subject. I admit

that I am "heavyweight" (I should loose at least 10 kilos, 20 or 30 would be

even better).

I have sent an e-mail to RADSAFE which contains in my opinion all which has

to be said about that subject and which is well founded with decades of

experience. Then I read about 100 % gamma radiation emitted by Sr-90, I read

about the decay of Sr-90 to Y-90m (!!!!!), I read that no bremsstrahlung can

originate from the Sr-90 betas, unless with lead shielding (what else would

one use?) and then it can be neglected. Worst of all I read in one posting

that beta radiation can be shielded with paper!!!!



I draw the following conclusions:



First of all most people do not read the postings of others regarding the

topics they are going to comment on. In the best case, they repeat others

reasoning, in the worst case they make wrong statements about issues, which

have been commented on correctly. The results: "The specialists have

differening opinions."



Secondly: Many RADSAFErs comment on topics which they do not have any

knowledge about. This topic is something I know well - but what can I

believe from  postings regarding other topics, where I have only a poor

background? Should I extrapolate?



Thirdly: If the "antis" had some real experts, they could distribute easily

that the "experts" on RADSAFE have no clue about such issues - and nobody

could prove that they are wrong.



Comments to RADSAFE, flames to me personally!



Franz









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