The chatter of Russian spoken at the Nevada Test Site Wednesday will be a first as up to 45 Soviet scientists monitor a nuclear test planned for noon.

Journalists' scratching pens and clicking shutters will be heard for the first time since 1986 inside the test control room when the bomb, code-named Kersarge, is detonated.But despite the new twists to nuclear testing, protesters outside - and possibly inside - test center gates will be chanting a message that has changed very little.

"This test is completely unnecessary," said Chris Brown, spokesman for the American Peace Test.

The Soviets have been invited to the test site to participate in the test just as U.S. officials have been invited to join the Soviets on their home turf sometime in September. Both sides are attempting to refine measures to verify the magnitude of each other's tests.

Verification, it is hoped, will lead to the Senate's ratifying a 12-year-old treaty both atomic superpowers claim they have lived by - and have been accused of breaking - since the Threshold Test Ban Treaty was signed 12 years ago.

The treaty sets a limit of 150 kilotons on nuclear devices detonated in underground tests.

Nick C. Aqualina, manager of the Department of Energy's Nevada Operations Office and a top DOE official overseeing the Joint Verification Experiment, told the