SAN DIEGO - For the first time, a source from inside the San Onofre nuclear power plant has come forward to warn that restarting the power plant is too dangerous.

"There is something grossly wrong," said the inside source, a safety engineer who worked at San Onofre and has 25 years in the nuclear field.

The source, who requested anonymity, is not alone in concerns over the safety San Onofre Nuclear Generating Station (SONGS).

*Click here for a timeline of San Onofre incidents

The concerns stem from inside the concrete containment walls, which house steam generators unique to the plant.

Japanese manufacturer Mitsubishi Heavy Industries (MHI) built replacement generators for the aging nuclear plant in 2010 and 2011.

"There were many, many changes," said Dr. Joe Hopenfeld, a former employee of the Nuclear Regulatory Commission (NRC). He described himself as pro-nuclear.

Hopenfeld spent his entire professional life working with steam generators and nuclear power. Though he lives in Maryland, he is familiar with San Onofre, which is run by Southern California Edison (SCE).

The new generators were designed to provide low cost power for decades. Instead, they shut it down in just eleven months because of a radiation leak.

"The manufacturer didn't have experience in this size unit," said Hopenfeld. "I have reviewed thousands of pages of assessment and reports that Edison has submitted."

He says the 2011 radiation leak that shuttered the plant revealed a potentially catastrophic problem with the tubes that carry scalding water.

"As far as I'm concerned, it's a very serious risk," Hopenfeld said.

Tubes carry water to and from the reactor core. This creates steam, which  turns the  turbines and produces energy. 

"The tubes operate under very high pressure," Hopenfeld said, adding there is no protection provided between the tubes, which are placed in rows, to keep them from hitting each other.

Our sources said the redesign of the generators had unintended consequences. Tubes began hitting each other, creating cracks.

"These tubes were hitting each other -- that's dangerous," said Team 10's anonymous source.

He wants to remain anonymous because he told Team 10 he fears for his safety.

http://www.10news.com/news/investigations/san-onofre-insider-says-nrc-should-not-allow-nuclear-restart-042513