RE: A Question for Power Reactor Types and others with portal monitors.

[Carol Marcus <csmarcus@ucla.edu>]

At 11:36 AM 4/8/2004, Stabin, Michael wrote:



>I agree with John J - first, I know you meant Tc-99m, but mostly I am

>surprised that any place would have enough Moly breakthrough to be so

>noticeable. This is supposed to be a major QA point.



Dear All:



Moly-99 does not come out of Tc-99m generators anymore.  It was a factor 

with target moly generators, but ceased to be a factor with fission moly 

generators, which have been used exclusively in the USA for several decades.



I only know of two documented cases of moly breakthrough since we switched 

to fission moly.  One occurred when a few generator columns were assembled 

backwards at the factory (probably 15-20 years ago), and another occurred 

when a generator was left out in very cold weather, froze, and the column 

cracked and leaked after thawing (maybe 10-15 years ago).



Ciao, Carol



Carol S. Marcus, Ph.D., M.D.

<csmarcus@ucla.edu>