[ RadSafe ] Re: Costs of "rad protection"?

[JGinniver at aol.com]

In a message dated 24/10/2005 22:12:56 GMT Standard Time, didi at tgi-sci.com  
writes:

While I  don't really know how radioactive these conductors are (my guess is
the  activity is negligible),


According to the IAEA Tecdoc 1357 on the " Management of  disused
long lived sealed radioactive sources (LLSRS)"  
 
SNIP>In the past 226Ra and 241Am were used in lightning rods, which have  
mostly been removed and collected. Their activity is usually in the order of 40  
to 70 MBq. In few cases an activity in the range of GBq had been  used.<SNIP
 
which if at least obe was mounted on 1000 buildings would give 40 to 70 GBq  
is not insignificant.  It also depends whether the quoted activity is just  
for Ra-226 as the daughter isotopes could (if I recall correctly) multiply the  
total activity present by a factor of 6 if the Radium is contained inside a  
sealed capsule. 
 
Must of the emphasis on the protection of long lived sources is to prevent  
their acquistion by terrorists in so called 'dirty bombs', however I do feel  
that they would be little chance that someone could obtain a significant number 
 of these without their loss being detected.  I believe the real concern is  
the long term management of items such as these that may not be properly  
controlled and disposed of leading to the potential that the public could  
unwittingly come into contact with these items, or more likely that they could  be 
accidentally re-cycled in scrap metal leading to a release from the recycling  
plant the need for expensive decontamination of the furnace.
 
Perhaps the question should be whether the Government in Singapore should  
have required the removal of these, resulting in a one off cost, or instead  
opted to have instituted a regulatory framework for the long term management  
which could have resulted in higher costs of the remaining lifetime of the  
lightning conduction systems?
 
Personally I suspect that it's cheaper to remove these items on masse and  
arrange for direct disposal, the IAEA has provide quite simple guidelines in the 
 past for direct disposal of Radium to deep boreholes which should be quite 
cheap  to achive.
 
Regards,
        Julian