[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Sewage Disposal and Solubility
1. Unfortunately, Melissa is right that complications can occur no
matter what the solubility of the radionuclide is. As a specific
example, I was involved with the decommissioning of an old I-125
RIA lab. That lab had only sink disposed of soluble/sewerable
solutions. The process used a dedicated sink and included copious
flushing with normal tap water to ensure perimeter concentrations
at the main sewer trunk to the city did not exceed license limits.
2. When the pipes were dug up, sludge was found that had accumulated
inside the pipe over the period of many years the facility had been
used (not always as an RIA lab). Sure enough, the sludge contained
measurable quantities of I-125. The pipe was dug up and stored for
disposal as radwaste (the facility hadn't been approved for DIS for
that form of material and half-life radionuclide). Some sludge with
detectable I-125 was found some distance away in the secondary's
prior to the main trunk line.
3. Did any of this represent an external hazard to any plumbing/
sewer contractor employees? No. It is most unlikely the sludge
represented an internal hazard as well (as someone said earlier,
the biological dangers would greatly outway the radionuclide's!).
Sludge happens, some of it from previous lab uses (and it may have
some avidity for the solution being disposed of), and a simple
flow model and perimeter concentration/total activity calculation
probably DOES NOT represent the actual dynamics of the sanitary
sewer system (even in new buildings).
-----------------------------------------------------------------
SU Michael P. Grissom, AsstDir ES&H Env/RadProt/WasteMan SU
SLAC Stanford Linear Accelerator Center, MS 84 SLAC
SU 2575 Sand Hill Road, Menlo Park, CA 94025 SU
SLAC (415) 926-2346 Fax: (415) 926-3030 SLAC
SU Email: MIKEG@SLAC.STANFORD.EDU SU
-----------------------------------------------------------------
The opions expressed above are those of the author alone and do
not represent those of the Stanford University or the US
Department of Energy.
-----------------------------------------------------------------