Protesters said they see the plant as a nuclear threat on the brink of a nuclear catastrophe."Commercial nuclear power is dangerous business plain and simple," said Irvine City Councilman Larry Agran.The plant's two reactors remain offline after a leak was discovered in one.San Diego State University associate professor Murray Jennex helped build the plant and has been a nuclear engineer for decades."The steam generator's been operated in a way that's a little different than the design assumes, so there's more vibration," he said.More vibration means more wear, but Jennex says monitors are in place. He personally checked radiation levels and said they are no higher near the plant."It's no different," said Jennex. "No greater than it is anywhere up and down our coast."Protesters like Ray Lutz are not buying it."There's no safe dosage of this radiation," said Lutz.Protesters say that when a major disaster occurs, about 8.4 million lives will be on the line."My concern is an earthquake or a tsunami melting this nuclear plant down," said protester Greg Bennett. "We're wrecking the lives of inhabitants, the animals, the fish." A fault has been found about 10 miles off the coast, so an earthquake is possible. "The size of tsunami is really determined by the size of the earthquake," Murray said. Protesters raised the question of whether the plant would withstand a 9.0 earthquake. Jennex told 10News the plant is built to withstand what is expected. "This is actually a relatively stable area," he said. Jennex said during a worst-case scenario, a 6.8 to 7.0 magnitude earthquake and a 22-foot tsunami can be expected. Plant officials say they have a 30-foot tsunami wall. Jennex told 10News Japan only had a jetty that was about 6 to 8 feet high and their emergency backup power was stored at sea level. Lutz said he wants to see the plant shut down and swapped out with renewable energy, but Jennex says that could create even more of a mess."The replacement power is going to be coal-generated power," said Jennex. "That, from an environmental standpoint is much worse than San Onofre."He said it is simply not necessary."I consider it safe," he said. "I've never moved my family never considered moving away from the region."The plant is trying to extend its license for another 25 to 30 years and has proposed a study to assess its safety. The study would cost about $64 million and consumers may have to foot the bill.