The wing spar structure of 787 will not be made of composites so it will hold fuel just like any other modern airliner.
I'm not trying to flame your post. I don't however understand the premise behind it.
From the Boeing website http://www.boeing.com/commercial/7e7/background.html
"Boeing has announced that the majority of the primary structure including the fuselage and wing on the 787 will be made of composite materials."
While it's not specific about the spars it does say the majority of the primary structure. Even if the spars are aluminum the skins, ribs, and stringers are the only other primary structure in the wing. If they are composite they will also be in contact with the fuel. The structure of the wings that forms the integral tanks in modern airliner's wings IS
the primary structure of the wings. There are composite components of current wings but they are limited to flight control surfaces and secondary structure(closeout panels and such). If Boeing states that most of the PRIMARY structure of the 787's wings will be composite how do you figure it won't be. Is the Boeing site misleading us?
[Edited 2005-02-14 11:59:24]