An aqueous tritium breeding blanket concept with natural lithium has been proposed. Lithium oxide dissolved in pressurized heavy water forms a saturated solution of LiOD in the liquid phase and the remainder is suspended in the solution or forms a breeder solid skeleton. The tritium breeding ratio (TBR) and nuclear heating are calculated using a one-dimensional discrete ordinates transport code. The heavy water solution blanket with 4.3 wt% lithium, saturated solution at 373 K, may give a TBR of 1.07. A larger TBR can be obtained without a neutron multiplier or 6Li enrichment when the existence of dispersed particles is permitted in the solution. The TBR does not fall below unity until 6Li is depleted to less than 4 at%.