RE: thorium in aircraft components

["Franta, Jaroslav" <frantaj@aecl.ca>]

I believe that somebody on Radsafe was asking about this a few months back.
I just happen to have come across  this interesting item...
 
http://www.wvi.com/~lelandh/d21~1.htm
<SNIP>
So far, attempts to display these engines 
have been stopped by the environmental concerns of some authorities. Much of
the 
centerbody construction is a Magnesium Thorium alloy. It may not be possible
to 
overcome this caution, but I would like to see such a display as a means to
educate 
aviation enthusiasts about the success of ramjets, as used in the US. 
<SNIP>
The "Museum of Flight" in Seattle, Washington has the only M-12/Drone
display combo in existence. 
<SNIP>

....I believe I read somewhere that the museum displays are engine-LESS.

http://www.awgnet.com/aviation/avi_news.htm
NASA Eyes Secret D-21
For RLV Engine Tests 
CRAIG COVAULT/CAPE CANAVERAL 
Skunk Works' Mach 3 recon drone would test rocket-based combined-cycle
engine for shuttle replacement 
<SNIP>
The last known D-21 operational mission was flown in 1971, and the remaining
D-21s were placed in storage. The program remained highly secret for many
years until revealed by the U.S. Air Force in the late 1970s, but many
aspects of the project are still classified. 
At least 38 D-21s were built, but only 21 were ever flown, 17 off the B-52.
The disposition of about 10 remains unknown, while several have been given
to NASA and museums. 
The D-21 is 42 ft. long with a 19-ft. ogival chined delta wingspan. The
vehicle weighs 11,000 lb. and was powered by a 34,000-lb.-thrust Marquardt
ramjet.
<SNIP>

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