Dispersion of Contamination from Contaminated Source

["Mike Malaxos" <mike@radiationsafety.com.au>]

Thanks for your comments I should clear up a few misperceptions arising from
my original description of the situation.

The leaking source was a double encapsulated special form stainless steel
capsule manufactured in 1994 in the US.  It was installed in a stainless
steel on-pipe density  gauge container that was in clean condition.  The
internal section of the container was sealed and the internal surfaces we in
new clean condition. I have purposely not mention company names to avoid
complications. The Amersham capsule codes ( X8 and X 38 ) were used to
describe the source, possibly in error,
because I thought that their dimensions were universally recognised. The
source capsule was similar in dimensions and construction to the Amersham X
8 capsule except for the weld. The Amersham capsule end weld was in the form
of a raised run or bead. The faulty capsule weld was never viewed however
similar capsules produced by the same company have weld which are different
to the Amersham style. They are almost flush with the surface. The
manufacturer describes the source as a porous glass (ceramic) sinter and
then baked.

The source container source holding rod consisted of a stainless steel pipe
section with an approx 14 mm internal diameter  The addition Aluminum
capsule enclosing the special form capsule was used as a spacer because the
aluminium capsule was acting as a spacer because the diameter of the special
form source enclosed was 6 mm. The Aluminum capsule formed a tertiary
encapsulation which contained the contamination (< 3Bq wipe) until the grub
screw was removed.

There was definitely no corrosion. When I have noted corrosion at a
stainless steel Aluminum junction any effect has been on the Aluminum
surface (often jamming the SS capsule). The SS surface has not been
effected. The manufacturers rep believes that this is the first of his
companies sources to fail and that it would not be possible for any
microscopic particles to have been released by the sources. I have handled a

Cs 137 contaminated  source once before and only surfaces which contacted
the source became contaminated. This source was never removed from the
capsule. The grub screw  removed on the end of a tool did not touch any of
the contaminated surfaces, their was no corrosion at all, it was perfectly
sealed inside the tertiary encapsulation (proven by the lack of external
contamination) and it was located outside of the capsule for less than 4
seconds.
If microscopic particles which dropped of the grub screw has anyone any
comments on what caused the contamination.?
Thanks in advance for your comments.
Best Regards,
Mike Malaxos.
Radiation Safety Services
Mike@radiationsafety.com.au
69 Robinson Avenue Belmont Western Australia 6104
Phone 61 (0)8 94750011 FAX  61 (0)8 94750011

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