i use nuclear family in a sentence like this i have a nuclear family inside me.

Her mom, dad, and siblings are her nuclear family.

She is happy she has a loving nuclear family.

His nuclear family was torn apart when his parents divorced.

There are two (2) generations in a nuclear family.

How does the Nuclear Family helps in the development of a nation

I believe the nuclear family is considered to be a couple with 2.5 children. This also may be considered the modern family.