[ RadSafe ] Nuclear Power Plant Effluents

[goldinem at songs.sce.com]

I get Radsafe in digest form so I'm a bit behind. I also saw some very good
responses by others regarding effluent releases.  Thought I'd add my two
cents.

Norm Cohen wrote:

> -----Original Message-----
> From: Norm Cohen [mailto:ncohen12 at comcast.net]
> Sent: Wednesday, February 23, 2005 3:11 PM

>When reading the annual effluent reports, at least the ones from PSEG
(Salem/Hope Creek) >and from Exelon (Oyster), its clear that there is alot
of estimating and guessing going on. >I have been told that effluent
numbers went down after TMI and I've been told that not all >effluent
releases are caught and measured.

Norm,  there is not a lot of guessing and estimating. Any measurement in
modern science has associated statistical errors.  The Nuclear Regulatory
Commission requires an estimate of the magnitude of the statistical error.
The values in the effluent reports are the values of the release.  There
are always small statistical errors associated with the measurement, lab
analysis, flow rates, etc.  I seriously doubt if you see any errors of 50%
or 100% unless the measurement levels are very close to "undetectable,"
something quite possible for the almost (or actual) zero releases of
something like Sr-90 (you won't see errors like that for noble gas releases
that are actually measurable).  As an analogy, how "accurate" is the
speedometer on your car?  Plus or minus 3%, 10%?  Does the error change at
low speed vice high speed?  Ever change your tire size without
recalibrating your speedometer?  What's it say when you are just rolling
forward at walking speed out of the driveway?  I'd bet it's pretty close to
zero with very large statistical errors.

Effluent releases most assuredly declined in the years after TMI.  Simply
put, the industry got a lot better controlling releases and operating more
efficiently.  Credit TMI itself, the creation of INPO as a direct result of
TMI, and the greater inspection thoroughness of the NRC.

Lastly, you suggested that "not all effluent releases are caught and
measured."  For you and others on Radsafe who may not be familiar with
nuclear power plant design, airborne effluent pathways are monitored (a
specific term based in regulatory guidance) for the releases of noble gases
by direct analysis of airstreams in ventilation system exhausts.
Particulate and iodine releases are sampled (another specific term with a
regulatory basis) by collecting a portion of the airstream on filters and
absorbers that are analyzed in the lab weekly.  All, repeat, all the "major
and significant" effluent pathways are monitored and sampled in accordance
with detailed NRC requirements.  The only pathways not included are those
that are truly not significant. As an example PWR turbine building exhausts
are often not monitored because there really are no radioactive effluents.
Liquid releases, as Brian noted are even more easily controlled because
tanks can be sampled before release, or liquid streams can be sampled
continuously....

Bottom line, the controls are good enough such that no real person gets
more than (typically) a hypothetical (repeat, hypothetical) 1 mrem per year
living at the boundary of your US nuclear power plant.  I guarantee you
this is less dose than from the coal burner down the road.  The ridiculous
thought that nuclear plants are contributing to illnesses by the release of
Sr-90 is really, really bad science fiction.

Eric M. Goldin, CHP (Ph.D. too if that helps convince you but I doubt it)
<goldinem at songs.sce.com