New Build - Non Draught Chimney

I intend to build a new house next year and the house will have 2 chimneys for aesthetics more than anything. I'll probably install a wood pellet boiler. If I don't intend on using the chimneys for solid fuel fire then what way should the chimneys be built so there will be no draught? The walls will be standard block build with partial fill cavity. Thanks

In case you decide to build real/functional chimneys/fireplaces then perhaps might be of interest?

Thanks ClubMan. All the links however seem to suggest ways of fixing the problem after it's happened...? is there no proper way of building functional chimneys with proper draft proof facilities build in, e.g. damper?

If I decide to go with the non-functional option I assume this will be easy for my engineer to design?