Re: Contaminated Hosp Pipes

[Mike Grissom <mikeg@SLAC.Stanford.EDU>]

General thoughts,

Organic crud probably is accumulating iodine, and it
is likely that corrosion centers/pits/etc. are
also accumulating iodine.  Some of this is chemical,
some mechanical, all of it is very difficult to 
remove in situ.  If you don't feel comfortable
waiting for decay to happen, a good "roto-rooter"
job likely will help some.

The only alternative that I have heard of involves
removal of all the piping (most expensive and
disruptive).

The drain pipe clean-out will probably reduce the
levels, presently about 0.5 mR/h general area and 3 mR/h
at the pipe--using the ancient exposure rate units--which presumably are
the highest levels found in the surveys.  
How accessible are these pipes? If members of the general
public can't readily get access, perhaps some labels
warning against loitering or prolonged contact would
suffice.  If there are areas with levels greater than 
5 mR/h at 30 cm from the surface of the pipe, posting as a
radiation area would be required in the USA.

For the long term, you might consider, if possible 
in your hospital, placing radionuclide therapy 
patients in rooms on lower floors.

Good Luck,

MikeG.

At 08:26 AM 6/18/97 -0500, you wrote:
>ANY THOUGHTS ON THIS PLEASE:
>
>Patients receive up to 7.4GBq (200mCi) I-131 for Ca-thyroid radionuclide 
>therapy. This is administered on the 6th floor of our hospital. 
>
>Excreted I-131 from these patients passes through cast ...