Does Iran want to build nuclear weapons?

In order to answer this question, we must first understand how nuclear weapons are built. To build nuclear weapons, you of course need uranium. Uranium, a naturally-occurring heavy metal, comes as uranium 238 or 235. Both are radioactive and will decay into other elements, given time, but only the latter can be forcibly split when neutrons are fired at it. This is the basis of a nuclear bomb. In a nuclear bomb, percentage of uranium 235 should be more than %80, and ideally should be around %96. But, for every 25,000 tonnes of uranium ore, only 50 tonnes of metal are produced. Less than 1% of that is uranium 235. Uranium 235 is also required for peaceful usage of uranium, for example to run nuclear reactors. Therefore, countries build uranium enrichment facilities to create uranium 235.

In theory, any country who has uranium enrichment facility could build nuclear weapons. Recipe to build a nuclear weapon is not a secret, when you reach certain amount of uranium 235, you can build nuclear weapons.

But does Iran want to build nuclear weapons? Iran does have an Uranium Enrichment Facility, located in Natanz. Therefore, Iran is able to build nuclear weapons if Iran wishes to. Despite this, Iran does not currently have any nuclear weapons, and according to Ali Khamenei's fatwa against nuclear weapons, Iran does not want to build nuclear weapons. According to this fatwa, nuclear weapons and other weapons of mass destruction are haraam according to Islam. Because according to Islamic law, you are not supposed to kill women and children who does not fight, and mass destruction weapons kills everyone who is in the range of the weapon.

This fatwa of course did not remove the suspicions that Iran will build nuclear weapons someday. Mentioned fatwa is said to have only religious binding, which won't stop Iran to build nuclear weapons if they wish to. Some countries, most notably United States wants Iran to close its uranium enrichment facility, so Iran won't be able to build nuclear weapons. This way, Iran also won't be able to use uranium for peaceful purposes, therefore Iran obviously does not accept this.

In any case, Iran has ratified Treaty on the Non-Proliferation of Nuclear Weapons, which states non-recognized nuclear weapon states will not build any nuclear weapons. Iran is also part of International Atomic Energy Agency, which promotes peaceful usage of atomic energy.

Will Iran build nuclear weapons someday? That would depend on who you ask, but I believe Iran does not need to build nuclear weapons in peacetime, and will only consider building them in wartime.