[ RadSafe ] Article on Wired on Thorium reactors

[John R Johnson]

Jaro and other radsafers

I'm sure Jaro knows this but others may not. AECL had a thorium fuel cycle R
and D program in the seventies and eighties because there was no "proven"
supply of U-Nat for the CANDU reactors.

One of the problems with Th-Nat is that intakes of the ALI can not be
detected by in vivo, urine or fecal monitoring. That is why we developed a
thoron in breath monitor (TIBM).

A discription of thoron exhalation can be found in A MODEL TO DESCRIBE
THORON EXHALATION FOLLOWING AN INHALATION EXPOSURE TO THORIA POWDERS; J.R.
Johnson and B.F. Peterman;  Published in the Conference Proceedings of the
Workshop on Lung Modelling for Inhalation of Radioactive Materials, Oxford,
UK, 1984 March.  EUR Report 9384, Commission of the European Communities,
Luxembourg (1984) 193-196.

We also developed a personal air monitor for worker. See  PERSONAL AIR
SAMPLING AT AN EXPERIMENTAL FUEL FABRICATION LINE; F. Kalos and J. R.
Johnson; PNL-SA-14225, CONF-8510235 (1987) 349-355.

 _________________
John R Johnson, Ph.D.
*****
President, IDIAS, Inc
4535 West 9-Th Ave
Vancouver B. C.
V6R 2E2
(604) 222-9840
idias at interchange.ubc.ca
*****
or most mornings
Consultant in Radiation Protection
TRIUMF
4004 Wesbrook Mall
Vancouver B. C.
V6R 2E2
(604) 222-1047 Ext. 6610
Fax: (604) 222-7309
johnsjr at triumf.ca

-----Original Message-----
From: radsafe-bounces at radlab.nl [mailto:radsafe-bounces at radlab.nl]On
Behalf Of Franta, Jaroslav
Sent: July 7, 2005 1:49 PM
To: 'radsafe at radlab.nl'
Subject: RE: [ RadSafe ] Article on Wired on Thorium reactors


The specific reply to Marco's comment is this :

<quote>
Intrinsic proliferation-Resistance of 232Th-233U and burning plutonium in
fast neutron reactor in 'once-through cycle'
<snip>
Th-based fuels and fuel cycles have intrinsic proliferation resistance due
to the formation of 232U via (n,2n) reactions with 232Th, 233Pa and 233U.
The half-life of 232U is only 73.6 years and the daughter products have very
short half-life and some like 212Bi and 208Tl emit strong gamma radiations:
0.7-1.8 MeV and 2.6 MeV respectively.
Hence, 232U could be utilized as an intrinsic proliferation-resistant
barrier for diversion of highly enriched uranium (HEU) and weapons grade
plutonium (W-Pu) for nonpeaceful purposes.
For incineration of WPu or civilian Pu in fast reactors utilizing
'oncethrough' cycle, (Th, Pu)O2 fuel is a better option, as compared to (U,
Pu)O2 [15]. In thoria matrix fuel, plutonium is not bred, instead 232U is
formed in the spent fuel which ensures proliferation-resistance because of
the high gamma radiation associated with the daughter products. In addition,
these fuels could be directly disposed in permanent repositories taking
advantage of the high chemical stability of and inertness ThO2.
<end quote>

......from
http://www-pub.iaea.org/MTCD/publications/PubDetails.asp?pubId=7192
Thorium Fuel Cycle - Potential Benefits and Challenges
IAEA-TECDOC-1450, 2500, ISBN 92-0-103405-9, English. 15.00 Euro  Full Text,
(File Size: 1900 KB).
http://www-pub.iaea.org/MTCD/publications/PDF/TE_1450_web.pdf


Jaro
^^^^^^^^^^^^^^^^^^^



-----Original Message-----
From: Franz Schönhofer [mailto:franz.schoenhofer at chello.at]
Sent: Thursday July 07, 2005 2:49 PM
To: 'Marco Caceci'; radsafe at radlab.nl
Subject: AW: [ RadSafe ] Article on Wired on Thorium reactors

<SNIP>
I wonder, what the opinion of the RADSAFE community is. Most of all I
believe that there are collegues out there, who might know much better than
I do....




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