I have had 2 occasions where 1 or 2 CTR tanks pumps were inop and we had around 2.5 tonnes in the CTR tank. This fuel must be considered as payload as it may not be usable in-flight.
For this reason the effect it has on weight and balance and must be accounted for. Not just for T/O but especially for LDG. It may put the aircraft outside the forward limit for LDG.
Your manual should give the proceedure for this situation, it will be around -8 I.U. per tonne of fuel correction.
Hope that helps a little.