Re: Self Shielded Irradiators

[Michael Williamson <m.williamson@mailbox.uq.edu.au>]

I have the answer to one of Kent Lambert's questions

Are there written standards that these devices must
>meet?  Are actual tests performed on prototypes?  I would appreciate
>references if possible.

Yes, there is a standard; it's ANS N43.7 "Safe design and use of
self-contained, dry source storage gamma irradiators [category 1]".  This
US standard was written in 1977 and reissued  (or re-endorsed) in 1989 and
is to the best of my knowledge still current.

We recently bought a refurbished Gammacell 220 from Nordion in Canada.
With a bit of prompting they were able to demonstrate compliance with the
ANS N43.7.  Amazing as it might sound, I don't think Nordion had been asked
to do this before.  Other maufacturers like JL Sheperd may already have
demonstrated compliance for some of their products.

While the standard specifies many laudable safety features, the more
significant fire and impact resistance requirements are imposed under the
IAEA Transport Regulations in the form of requirements for Type B
containers.  Any large activity, self-contained irradiator will necessarily
have to meet these requirements and receive certification from a competent
national authority, e.g. the US DOT or the Canadian AECB.

Have a look at the Type B tests to gain some idea as to the stringency of
the requirements.  Some groups have argued that they're not stringent
enough and a new category of container has now been defined for air
transport: the Type C.  These new Transport Regs are found in "Regulations
for the safe transport of radioactive material' issued by the IAEA in 1996
as No ST-1, the first document in a new Safety Standards Series.  I doubt
if any national regs have incorporated ST-1 yet but this is how it is going
to go in the future.

Regards




Michael Williamson
(m.williamson@mailbox.uq.edu.au )

Radiation Protection Adviser

Occupational Health & Safety Unit
University of Queensland
Brisbane 4072
Australia

ph +61 7 3365 4504
fax +61 7 3365 1577

The opinions expressed in this communication are those of the writer:
unless explicitly stated they should not be taken as representing the
official policies or views of the University of Queensland.