U.S., Soviets to Prepare for Joint Nuclear Tests Likely This Summer

The United States and the Soviet Union will start preparing for two joint nuclear test explosions, expected this summer, when talks on limiting such blasts open on Monday, Soviet negotiator Igor Palenykh said Saturday.

“There is every reason to expect the coming second round to produce agreement between the parties on all questions involved in preparation and conduct of the joint verification experiment at the Soviet and U.S. test sites,” he told reporters.

Palenykh spoke to reporters as the Tass news agency said in Moscow that the Soviet Union had conducted its second underground nuclear test of the year--a blast of under 150 kilotons aimed at “upgrading military technology.”

Tass said the blast took place at the testing range in Semipalatinsk in Soviet Central Asia.

Palenykh said he expected the Soviet-U.S. tests to be set off in the first half of 1988--around the time of a summit meeting between President Reagan and Soviet leader Mikhail S. Gorbachev due in Moscow in May or June.

The United States and the Soviet Union opened step-by-step negotiations on limiting, and ultimately halting, nuclear test explosions in November. Palenykh expected the second round to last six to eight weeks.

The joint tests were agreed upon to settle a dispute over the method for monitoring the yield of atomic blasts and to ensure neither side violates treaty limits.

The United States wants a method called CORRTEX. Moscow backs older seismic methods, such as those used for monitoring earthquakes.

The CORRTEX system places a cable near the test site and the crushing of that cable measures the test yield. Such a system requires warning and, therefore, cannot be used to monitor for cheating on a comprehensive nuclear test ban.

Only a seismic system could be used to detect cheating on a full nuclear test ban.