RE: Porcelain Electrical Insulators[Scanned]

["Dr Christoph Hofmeyr" <chofmeyr@nnr.co.za>]

Franz, Radsafers,

Obviously these insulators have been in use for an extended period. Apart from your explanation, which is plausible, I wondered about the possible deposition of radon daughters due to the electric field, in which case it might be of some relevance if it was AC or DC networks.  Such 'contamination' could be quite persistent due to the 22y halflife of Pb-210.

Chris Hofmeyr

chofmeyr@nnr.co.za





-----Original Message-----

From: Franz Schoenhofer [mailto:franz.schoenhofer@CHELLO.AT]

Sent: 01 June 2003 06:31

To: ray ilson; radsafe@list.vanderbilt.edu

Subject: AW: Porcelain Electrical Insulators[Scanned]









-----Ursprüngliche Nachricht-----

Von: owner-radsafe@list.vanderbilt.edu

[mailto:owner-radsafe@list.vanderbilt.edu]Im Auftrag von ray ilson

Gesendet: Dienstag, 29. April 2003 14:47

An: radsafe@list.vanderbilt.edu

Betreff: Porcelain Electrical Insulators







Hello Radsafers!



I have received a query about "Canadian Porcelain" electrical insulators

used on high tension electrical distribution power lines. It appears

that they are giving off radiation fields which were detected at the

gate of a waste station. The insulators were manufactured in 1953-1954.



I have not assessed these fields as yet but assume that the radioactive

material is embedded within the porcelain itself rather than being a

result of surface contamination, although both possibilities will be

checked.



Does anyone have any experience with such materials or could you direct

me to further information?



Many thanks, Ray



----------------------------------------------

Ray,

Porcelain may contain traces of thorium. White glaze for ceramics is mostly

manufactured using zirconium oxide, which frequently contains elevated

amounts of thorium. So the elevated activity might be due both to the

porcelain itself or rather the glaze.



Best regards,



Franz



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