Re: Spent Fuel Storage Pool Water Chemistry Control -Reply

["Mark A. Smith" <web25@charweb.org>]

JIm Hardeman's comment that, if you control the conductivity to <10 
microsiemens per centimeter, the clarity and pH take care of themselves, 
is essentially correct.  However, I would point out that at this low 
conductivity, pH may not mean anything.  First, if you use a standard pH 
meter to measure it, the values will be probably be wrong, since the pH 
meter operates on principles involving conductivity of the test 
solution.  With low conductivity, the meter is no longer being used under 
its calibration conditions.

Also, pH in low conductivity water is not necessarily a reliable 
indicator of corrosion potential.  Again, the low conductivity influences 
the physical and chemical reactions.

I have seen pools with conductivity <6 microsiemens/cm and still have the 
measured pH be on the acidic side, around 4.5 or so.  The question is, 
does that pH value mean anything?

Mark Smith
SteriGenics International
web25@charweb.org