On Soviet television, the workers in the front lines of the clean-up at the Chernobyl nuclear plant all wear white cloth caps, white mouth guards and white uniforms. They look eerily like surgeons operating with bulldozers and precast concrete blocks instead of scalpels and surgical thread.

They are operating on a patient they cannot touch. News reports about the clean-up stress the limited amount of time workers can spend in the contaminated zone - an hour in some cases, minutes in others.

Some of the crane operators setting up concrete walls between the damaged No. 4 reactor and the adjoining No. 3 unit sit in cabs with lead shielding. Other cranes and bulldozers close to the plant are operated by remote control. Workers Face Multiple Tasks

Within these constraints, described at length in press accounts and again at a news conference today, soldiers, scientists and engineers have been working over the last few weeks to carry out these tasks:

* Protect the Pripyat River and the groundwater in the area against contamination.

* Limit the spread of radioactive dust around the plant, in part by paving the ground with concrete.