Crusader and Beyond

Richard L. Garwin
Philip D. Reed Senior Fellow
for Science and Technology
Council on Foreign Relations
58 East 68th Street
New York, NY 10021
Work: (914) 945-2555
FAX: (914) 945-4419
INTERNET: rgarwin at cfr.org

In an interview on PBS-TV May 13, National Security Advisor Condoleezza Rice remarked that "Destruction of warheads would be hard to verify." The context was the announcement of the Bush-Putin treaty on limitation of operationally deployed strategic warheads to 1700-2200 in the year 2012.

Dr. Rice is ignoring the large amount of work already done in the government and the scientific community on just this topic. U.S. and Russian nuclear warheads have an external case, high explosive to compress the plutonium which serves as the fission bomb, and sometimes enriched uranium in the so-called secondary or fusion portion of the weapon. Nuclear weapons are disassembled virtually every day in the United States at the Pantex plant in Texas, and at one of four sites in Russia. For U.S. weapons, the plutonium primary, in its inert metal shell, is then stored at Pantex or in secure storage sites elsewhere. Enriched uranium is shipped to Oak Ridge National Laboratory for storage.

One could indeed have a U.S.-Russian treaty which required the dismantling of nuclear weapons above the agreed limit, with the secure and verified storage of the resulting weapon plutonium and weapon uranium. This process could be verified without conveying any details of weapon design to the other party. And such a treaty would well serve U.S. national security.

All that needs to be done is to transfer, cooperatively, a weapon from its deployed position to a sealed and tagged shipping container and to ensure that it reaches the dismantling site intact. The weapon would then enter an inspectable jointly-built room of modest size, where it would be dismantled. Four streams would leave the room, which would then periodically be emptied and inspected. One stream would be the plutonium "pit" in a light-weight shipping container, looking like a 55-gallon drum. Another stream would be the uranium parts in a similar container. The third stream would be the explosive, for disposal. The fourth stream is miscellaneous electronics and structure, which need not be destroyed or controlled under the treaty, but which the treaty might specify should be shredded.

There is no sensitivity attached to thorough monitoring of the explosive and miscellaneous streams to ensure that they have no plutonium or uranium. Close monitoring of the plutonium stream, however, could provide information on the composition and amount of plutonium-- matters on which the two parties are sensitive. And precision monitoring of the uranium stream could similarly provide information on the uranium components. But it is a simple matter to monitor the uranium stream with radiation detectors sensitive only to plutonium, and the plutonium stream with radiation detectors sensitive only to uranium. Because the disassembly room is periodically emptied and inspected to ensure the absence of plutonium and uranium, one can be certain in this way that any weapon entering the facility is dismantled and its crucial bomb parts sent to secure, verifiable storage. Indeed, not only could the U.S. monitor Russian storage and vice versa, but the International Atomic Energy Authority-- IAEA-- could have a role in monitoring both.

Russia and the United States have collaborated for years on joint programs to demonstrate warhead monitoring with suitable "information barriers", which can be used, for instance to ensure that a warhead has the same amount of plutonium as a standard warhead of its class, without revealing the amount. And even before warheads can be dismantled, the treaty could require that excess warheads be transferred to a central store in each country, monitored by the other side. This would contribute to countering terrorist use of excess nuclear weapons.

Of course, by abandoning the treaty, the host country could retrieve some of the stored components to rebuild nuclear weapons. The parties could prevent the ready reuse by shredding the uranium before putting it in the storage container at the dismantling site. Because plutonium dust is a severe health hazard, the pits could not be shredded. However, a pit might be enclosed in a ductile aluminum or copper bag, which could be crimped and sealed airtight and enclosed for added assurance in another ductile metal bag; the packaged pit could then be squashed in a press so that it would need to be remelted and refabricated for use in a weapon.

What stands in the way of verifiably dismantling nuclear weapons is not the inherent difficulty but reluctance to do so. This reluctance ensures that Russia will keep 10,000 or more nuclear weapons outside any treaty. We would be far more secure if these and our own surplus nuclear weapons were destroyed and their components securely and verifiably stored.