The three non nuclear principles were intended to

The Three Non Nuclear Principles were intended to keep Japan from ever developing or using nuclear weapons.

Explanation:

After the fall of the atomic bombs on Hiroshima on August 6, 1945, and Nagasaki three days later, in 1967 Japan adopted what is known as The Three Non Nuclear Principles.

All this has helped Japan, nowadays, to become not only in a peaceful but also pacifist country, adopting these measures and respecting and ratifying until the moment of the creation of this article. And not only that, but other countries have joined the initiative, declaring in equal conditions, and adopting in the same way these three same principles.

1st and 3rd : ) now lemme smash