[ RadSafe ] is uranyl oxide gas the greatest threat from the actinides?

[James Salsman]

Prof. Otto G. Raabe wrote:

> According to the Handbook of Chemistry and Physics, uranyl oxide 
>... decomposes on heating before it reaches its melting point.

If only the UO3(g) produced when U3O8 cools from uranium's burning 
temperature in oxygen also decomposed.

Sadly, the individual molecules have a strictly odd number of 
oxygens, so a pair as O2 are unlikely to escape.   The bond 
angles of the oxygen are about {0, 90, 175} degrees apart.  
Some of it will decompose, but if each U3O8 combustion product 
particle's surface produces 20% of the amount of UO3(g) which 
is produces by larger particles in pure oxygen, that means about 
2% of the burning U ends up as UO3(g) -- so, what proportion of 
that decomposes before it reaches air temperature?

Sincerely,
James Salsman