Nevada A-Blast Makes Arms Control History

Exactly on schedule and under ideal conditions, Soviet and U.S. technicians made history Wednesday by jointly monitoring a nuclear explosion beneath the Nevada Test Site, opening what participants said is a new chapter in nuclear arms control.

“This is an auspicious start for the Joint Verification Experiment and a critical hurdle for this process,” Energy Undersecretary Joseph F. Salgado said after watching technicians use a variety of technologies to measure the yield, or power, of a nuclear explosive that rippled the surface of Dead Horse Flat at 10 a.m.

‘One Step Closer’

“As a result,” Salgado added, “we are one step closer to completion of the verification protocols for the Threshold Test Ban Treaty and the Peaceful Nuclear Explosions Treaty.”

Despite optimistic predictions from both sides about those treaties, which were signed in the mid-1970s but never ratified by the U.S. Senate due to concerns about the ability to verify Soviet compliance, U.S. and Soviet officials remained at odds over how far the experiment here will advance the cause of strict new nuclear test bans.

Igor M. Palenykh, head of the Soviet delegation to bilateral nuclear testing talks in Geneva, said through a State Department interpreter that Wednesday’s experiment can and should lead to “further limitations of nuclear tests, both the number of tests and their yield.”

“The ultimate step, of course, is the total cessation of nuclear testing,” he said, recalling his country’s unilateral test moratorium of the early 1980s. “We plan to make every effort to achieve this objective.”

Palenykh’s U.S. counterpart at the testing talks, C. Paul Robinson, quickly stepped in to say that the United States is not nearly as keen to entirely do away with nuclear tests.

“The United States still believes that it must rely on nuclear testing just as long as it must rely on nuclear weapons for its defense,” he said. “But this event is proof that we are making progress on measures that will lead to a more stable world.”

The conflict aside, the Soviet and U.S. technicians and diplomats were generally jovial after the event, the first of two nuclear blasts planned as part of a Joint Verification Experiment designed to demonstrate the feasibility of several test-limitation verification technologies. The second explosion is planned for Sept. 14 at Semipalatinsk, the nuclear test site in Soviet Central Asia.

First Time

The tests are significant because they mark the first time each country has allowed technicians from the other to actively monitor a nuclear test at its secret nuclear proving grounds.

“Unprecedented is an easily overused word,” Robinson said, “but all of us seem to fall back on it to describe the events here.”

“Successful” was another word often used to describe the test.

“The test went extremely well,” said test controller Jim Magruder. “We think the test was a resounding success.”

Viktor N. Mikhailov, leader of the Soviet technical team, touched off a brisk round of applause in the control room 30 seconds after the detonation, when he jubilantly punched the air to signal he had received good news from Soviet technicians staffing recording equipment in a nearby building.

Wednesday’s test went off as planned despite a demonstration at the test site’s gate in Mercury, about 30 miles from the control room and 60 miles from the blast. Protesters said test ban negotiations are moving too slowly.

Prove Accuracy

None of the verification methods demonstrated Wednesday are new, so the experiment was not meant to prove accuracy, Robinson said. Rather, it was to show that the hydrodynamic method preferred by the United States is “non-intrusive”--that is, it can measure the bomb yield without also revealing secrets about bomb construction.

“The Joint Verification Experiment is not a contest between two brands of verification methods,” he said. “Rather, it is to demonstrate all of them and from that to develop a menu of options from which both sides may pick their own verification method.”

Bomb yield can be estimated with a hydrodynamic instrument that measures the speed of the explosion’s shock wave within a few yards of the explosion.

However, G.A. Tsyrkov, the Soviet deputy secretary for medium-sized machines, repeated the Soviets’ preference for teleseismic monitoring to measure ground vibrations thousands of miles from a blast site.

Different Methods

Three different hydrodynamic methods and two teleseismic techniques were tested Wednesday, and data from all will be shared between the two countries.

Information on test site geology and past tests in both nations was swapped last month. The first post-blast data exchange occurred just minutes after Wednesday’s explosion, when Soviet and U.S. technicians swapped computer disks of raw data. Other exchanges will continue until the testing talks resume this fall.

U.S. officials were reluctant before the shot to disclose the bomb’s yield, except to say it fell within agreement guidelines--that is, between 100 and 150 kilotons, roughly the punch of 100,000 to 150,000 tons of TNT.

The actual bomb was sealed in a red-white-and-blue steel container 8 feet tall and 88 inches in diameter. Before the bomb was placed 2,020 feet down a 2,200-foot hole in Dead Horse Flat last July, Soviet technicians were able to inspect the outside of the 15,000-pound device, which was sent here expressly for this experiment from the Los Alamos National Laboratory in New Mexico.

“This event has no other purpose than to test the monitoring devices,” said test director Joseph P. Behne from the Lawrence Livermore National Laboratory in California.