PUBLIC VIEWPOINT

Iran’s Nuclear Threat A Clear Danger

I am writing in response to two recent commentaries by my former physics professor, Art Hobson, concerning Iran’s nuclear weapons capability.

I graduated with a bachelor of science degree in physics in 1974. In the early 1980s I earned a graduate degree in nuclear engineering. Many of my grad school classmates were Iranians. Hence, I’ve followed Iranian nuclear developments closely over the years and think I have a rough notion of Iranian engineering capabilities.

My career hasn’t been in nuclear engineering. I recently retired after a long career as a mechanical design engineer for a large well-known military aircraft company.

Dr. Hobson is an expert physicist, but I don’t think he has detailed knowledge of the industrial and engineering requirements for militarily practical nuclear weapons.

Americans need to understand that Iran will almost certainly have nuclear weapons in the near future. By focusing on enrichment of Uranium-235, Iran has avoided several very large technical difficulties associated with plutonium.

These include producing Plutonium-239 sufficiently free of Plutonium-240 contamination to be usable in a weapon; and fabricating bomb parts from Plutonium-239 metal, which has the most complicated metallurgical properties of any element on the periodic table. Dr. Hobson’s Dec. 1 commentary describes the heavy-water reactor under construction at Arak as a potential source for weapons plutonium. I doubt this is correct because there is no evidence of construction of the large chemical processing plant needed to separate tiny amounts of Plutonium-239 from tons of neutron-irradiated uranium.

This reactor is more likely intended to produce tritium (a heavy isotope of hydrogen) for “fusion boosting” to increase the yield of fission weapons.

Dr. Hobson’s most recent commentary describes Israel as “the region’s only nuclear power.” He fails to mention Pakistan, which has provided technical assistance and possibly hardware to both North Korea and Iran. In particular, Pakistan reportedly has domestic capability to produce pulsed neutron generators for initiating the chain reaction in a fission weapon.

Iran’s Shahab 3 missile has a diameter of about 50 inches and a payload capacity of about 2,000 pounds, likely the limiting parameters for Iranian weapon designers.

Within these limits I believe Iran has the ability to produce an implosion weapon with a levitated, fusion boosted, Uranium-235 core having a yield of at least 20 kilotons and perhaps as much as 100 kilotons.

Such a weapon poses a mortal threat to Israel, and in the hands of Iran’s surrogate Hezbollah could easily be delivered via rental truck to the heart of a major American city near the uncontrolled Mexican border. Contrary to Professor Hobson’s comments, if a nuclear attack on Israel occurs, the U.S. does not have the political will, and is stretched too thin militarily to mount a major attack on Iran. Iran knows this and is emboldened by perceived American weakness. This is a very dangerous moment with disturbing similarities to the time of Chamberlain’s 1938 Munich Pact with Germany. There is no indication that any of our leaders understand this risk.

WILLIAM BRANDON

Fayetteville

Opinion, Pages 5 on 12/24/2013

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