Nine young people sprawled on the sunny campus lawn, indistinguishable from the other picnickers. Pigeons picked at the raisins and peanuts the group brought for lunch.

"We have to prepare for every contingency," Win Morgan was saying "Dogs, guns, gas."

He ordered the group to stand, Joel Harp, one of the members, lunged at the young man next to him, shouting "I'd like to break your f . . . head!"

His target raised an arm to block the assault.

The tiny band at George Washington University was training yesterday for the planned occupation of the Seabrook nuclear plant in New Hampshire next month. In a rekindling of student activism that virtually disappeared after the Vietnam war, the trainees now are planning protests against the commercial use of nuclear power.

"We intend to stay at the plant," Morgan told them, "so we'll actively resist arrest for as long as possible . . . But police in New Hampshire have been more violent than other police in other actions. We're going into the action with a nonviolent attitude, but we have to train for it."

As part of that training, the group was role-playing, trying to imagine how each would react to trying situations.

Harp, a veteran of the antiwar movement, explained his attack.

"You see, I went for you because I could tell that sometimes, in some situations, you feel violence is justified," he told his victim. "I wanted to see if you'd fight back. I, well, I really hope you're going to be able to control that at Seabrook."

Morgan, a Quaker convert who works in a real estate office but said he plans to go to graduate school, told his students they had to put themselves in the place of their opponents to understand what they are up against.

He divided them into groups of protestors and make-believe Seabrook construction workers who are expected to try to get into the partly completed plant.

He told them to expect trouble from the workers.

"Think what it's like to have four mouths to feed," Morgan said.

That's when Harp threw himself at his partner. Afterward, they debated whether the partner's instinctive defensive movement was the right thing to do.

Nonviolence is the key, Morgan explained, and nonviolence takes discipline.

Harp told the group what it's like to be gassed: "I remember I couldn't see; it hurt my skin. But the worst part about it was that everyone ran."

They discussed what to do if gas is used at Seabrook.

A suggestion that they throw the canisters back at police was rejected as dangerous and inflammatory. Bringing Lemon juice and scarves was viewed with more favor. Masks and helmets were discarded as potentially provocative.

"True, we don't want to get our heads hurt," said one, "but I think bringing helmets makes it seem like we're expecting violence."

Morgan suggested other scenarios.

"What if we were approached by a group of 400 or 500 policemen? What could we do as a group? Well, we could sing; we could join hands; we could go limp . . . "

Morgan has spent his last four Saturdays in all-day training sessions for the Seabrook demonstration.

"I'm spending every spare minute on this," he said. "I just don't want to see anyone get hurt."