Re: Tritium stack sampling

[FRAMEP@ORAU.GOV]

          Radev:

          Welcome to RADSAFE.  The feds/state might be coming down on
          you like a lead brick (all 27 lbs or so), your dog might
          have left home and your spouse might be considering the same
          thing, but you've always got a friend on the list.

          First, don't hesitate to take Mike up on his offer to help.

          A couple of additional references that are easy to obtain:
          NCRP Report 47 "Tritium Measurement Techniques". Its old but
          has some useful stuff in it, and ASTM D 3442 "Standard Test
          Method for Tritium Content in Air" It describes the use of
          silica gel but that can be replaced by molecular sieve if
          you are so inclined. The standard describes the construction
          of the catalytic convertor that Mike talked about. They are
          easy to make: we've used a tube furnace stuffed with 1 g.
          palladium powder, it has some advantages over copper, but
          not a lot. The powder/screen is kept in place with quartz
          wool. We operated ours at 500 C. These babies get hot.
          Precautions must be taken so people don't get hurt.

          Rather than water in the bubbler/impingers we used ethylene
          glycol, it worked better with our LSC cocktail than water
          and it was supposed to be less likely than water to become
          entrained/evaporate in the air stream.

          If you do the sample collection, adsorption using silica
          gel/ molecular sieve is easier. If you do the sample
          analysis, you probably prefer absortion with bubblers.

          For the water in the bubbler (or as a carrier to help
          extract the HTO from the adsorbant) its nice to use water
          with a low tritium content. We used water from deep
          aquifers, from Memphis if I remember correctly.

          Best wishes

          Paul Frame

          framep@orau.gov