It is at least NOT Juaa or Lottery in any way, because you do not lose any of your own money in any case. Even if you win any prize, you get your own money back without any deduction. It's just a deposit to govt.
In case of interest it is doubtful, but still it doesn't fulfill the definition of interest completely. Many Islamic scholars consider it as "Atia-e-Sultaani (Gift from Govt.)", which is given via draw to winners only. It is not a fixed or guaranteed return to depositors on their deposit and cannot be considered as Interest.
The current 40,000 bond, on which the govt is paying 1.5% per annum profit. This 1.5% is now interest as it is a determined interest on deposited money. The prize is a different thing.
Allah knows better!