[ RadSafe ] Skyshine measurements
JPreisig at aol.com
JPreisig at aol.com
Wed Mar 6 12:40:45 CST 2013
Skyshine is discussed in Patterson and Thomas's Accelerator Health
Cossairt's Course notes on Accelerator Health Physics.
Guess other Radsafers have commented on the meteorology of skyshine
For field measurements of Skyshine, perhaps use a portable MCA
counting system with NaI or Ge
detector, or whatever you have available. If there is a neutron
component, you can make flux density
spectra measurements with a set of Bonner Spheres and one or two LiI(Eu)
reactor neutron and/or photon/gamma signals are not highly variable in
time, so you don't need
7 LiI(Eu) detectors, just one or two. Bonner Spheres (polyethylene) are
fairly expensive. You can analyze Bonner data with BON4/BON5, LOUHI???,
MAXED??? or other unfolding codes available from
RSICC (Radiation Shielding Information Center at ORNL). If you end up
using an Anderson-Braun
detector only, maybe you would want to make a set of measurements as a
function of angle (measured
from horizontal) pointed up towards the sky.
Like the other guy said, you can mathematically model the problem
using MCNP (Monte Carlo
Neutral Particle Program). MCNPX can be used for high energy
neutron/hadron transport, but that may
not be necessary in this case.
Have fun. Regards, Joseph R. (Joe) Preisig
In a message dated 3/6/2013 10:34:03 A.M. Eastern Standard Time,
mso at forsmark.vattenfall.se writes:
One BWR plant is to do a power uprate to 120% of the original effect.
During the testing period there will be dose rate measurements in
selected places around the plant to observe changes in skyshine from
the steam lines in the turbine building. In the documentation it says
that the measurements should be done during weather with "low clouds".
This is supposedly because low clouds will give you a conservative
measurement. There is no source given and I don't have the necessary
software to make a model of it. So what I want to ask is if any of you
could say if it is obviously conservative to measure skyshine with low
clouds (compared to high clouds or sunny weather) and if there is some
standard practice for skyshine measurements around nuclear plants. Being
a humble chemist, it's not obvious to me, although it seems reasonable
that clouds could cause more scattering.
All the best,
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