[ RadSafe ] Air monitor question

[Bailey, Pete]

Hi John,



>... the airflow is reduced to the point were there isn't enough to produce turbulent flow, mixing,



First, I'm presming a 'typical' power plant stack with a few inputs to a plenum ( fancy "T" joint) that feeds

a 'stack', the iso sampler is way up the stack ( 1/2 to 2/3 way up).



Have you looked to the inputs of the Stack to actually say the lack of mixing is a 'real' problem, versus a perceived problem.

During the low stack flow condition, it may turn out the most like 'feed' of contamination is 'the' path feeding the stack;

in which case, mixing is probably quite good....





> or a velocity anywhere  near the that needed for isokinetic sampling.



For those perods of time, can the inputs to the Stack be 'grab' sampled ?

remember also, 'Isokinetic' doesn't really apply to Noble Gas....

If the inputs to the Stack are 'known' and one can make 'process knowledge based decisions' about the inputs,

maybe only one input needs to be grab sampled, and the with process knowledged determine when during low flow conmditions,

this grab sampling compensatory measure is neded.



well, that's my $ 0.02



   FPL Pete