You will need a reprocessing facility for that. Also depends on the type of reactor (as to what sort of reprocessing you need).
You can't simply take old fuel and machine a bomb pit out of it....weapons grade and reactor grade are two different levels.
If its a Plutonium reactor, forget about it. After a few weeks of operation you will have much Pu-240 contamination and not Pu-239 anymore. Its not even worth reprocessing.
Vice versa can be done (use old bomb material to make new reactor feedstock with a cpl simple steps for safety).
It depends. VVER is not a breeder reactor design so much of the waste (spent fuel) is not economically feasible to reprocess. BD hopefully has an agreement with Russia which can store such in siberian caves and things like that more easily than land BD can find.
There are also different levels of other waste...mid and low level waste that will also have to be stored.
However its overall a much misunderstood issue on the amounts concerned. Everyone thinks its many huge amounts of waste...when really its not and can be properly managed easily:
http://www.irpa.net/irpa10/cdrom/00820.pdf