|
Dear colleagues,
ISO 3999 (2000) - Radiation Protection Apparatus
for Industrial Gamma Radiography in Transition to the 3rd
Millennium
Jose Julio Rozental
Israel
----- Original Message -----
Sent: Wednesday, February 06, 2002 1:37
AM
Subject: Re: incident details
In a message dated
2/5/2002 1:34:33 PM Eastern Standard Time, neildm@ID.DOE.GOV writes:
A valid point. I had missed that part. Could the
iridium be in a
dispersible form? The iridium sources I knew of
were small metal pellets,
about BB shot size.
Dave Neil
neildm@id.doe.gov
The iridium sources I have seen
manufactured are in small disks, about 1/8 inch in diameter and about 1-2 mm
thick (these are approximate). The disks are stacked in a cup, a small
spring is added if needed to take up the extra space and the top is welded
closed. The source is strong and will withstand all kinds of abuse, but
an electric arc can do considerable damage, perhaps enough to release one or
more of the disks. If the can is breached, there will be a release of
the iridium oxide to the environment, but this material is fine and will
disperse and be just ordinary contamination, not very hot spots. Chunks of
iridium metal from a broken disk will be real hot spots. These are
thermally hot, by the way and will leave burn marks if they sit in one spot
for a while. Some of the burn mark may be radiation damage. In
other words, do not be stupid and pick this material up with your fingers.
The iridium contamination is very heavy an! d will fall out and not get
reentrained into the air very easily. Any airborne iridium goes away
quickly as it falls to the ground or floor or desktop or on you if you happen
to be there.
Best wishes to all...
John Andrews
Knoxville, Tennessee
|