The World : Soviets Stage Nuclear Test

The Soviet Union conducted its first nuclear test in more than 1 1/2 years, exploding a device on its testing range in Soviet Kazakhstan. The official Soviet news agency Tass, which issued a two-paragraph report on the test, said the yield of the underground blast was less than 20 kilotons. It was the first Soviet nuclear test since the Kremlin ended a unilateral test moratorium that took effect in August, 1985. The Soviets had said they would maintain the test freeze until the first American test blast of 1987. The United States conducted a test Feb. 2.