MOSCOW (AP) _ Radioactive waste spilled from a leaky pipe at a nuclear weapons plant in the Ural Mountains, the second accident in less than a month at the secret facility, officials said today.

The ITAR-Tass news agency said the accident Monday night caused no serious harm to workers at the Mayak plant near Chelyabinsk, about 930 miles east of Moscow. It quoted specialists as saying the doses of radiation were within acceptable limits.

The Atomic Energy Ministry said a pipe carrying radioactive waste solution depressurized and leaked about 70 cubic feet of ''radioactive pulp.''

The accident contaminated about 120 square yards of the factory's grounds with three-tenths of a curie of radiation, the ministry said. By comparison, the Chernobyl disaster in Ukraine in 1986 released about 50 million curies.

The earlier accident at the Mayak plant occurred July 17, when a chemical explosion reportedly occurred in the sorption column, which extracts plutonium 238 for use in nuclear weapons.

The explosion spewed radioactive isotopes into the atmosphere.

The Mayak complex, created in the late 1940s to make plutonium for the first Soviet nuclear bombs, has a long history of accidents and pollution. It is surrounded by radioactive reservoirs, lakes and rivers filled with liquid nuclear waste.

The worst accidents at Mayak were in 1957, when a chemical explosion at a nuclear waste tank contaminated large areas of the southern Ural Mountains, and in 1967, when winds carried radioactive particles from the drying-up and polluted Lake Karachai across villages and farm lands.

Hundreds of people have suffered radiation illness as a result of these accidents, long kept secret by the Soviet authorities, and thousands have been evacuated.