GRANBURY — Luminant Generating Co., which has applied for a license to expand the Comanche Peak Nuclear Power Plant from two to four reactors, and opponents on Thursday clashed over the likelihood of a catastrophic radiation leak from an event such as a terrorist attack.

They also debated whether Luminant gave enough consideration to renewable energy sources such as wind and solar to generate electricity for its customers.

Both sides made oral arguments before a three-judge panel of the federal Atomic Safety and Licensing Board. The public hearing drew about 60 people.

The Central Jury Room at the Hood County Courthouse annex looked like a sea of dark suits as lawyers for Luminant, intervenors opposing the license application and the U.S. Nuclear Regulatory Commission staff spent hours arguing over the wording of the contentions.

The panel is expected to make a decision within several months.

Luminant attorney Steven Frantz told the board members that a combination of wind and solar could not reliably generate large volumes of electricity to provide 24/7 service.

He said that there were “no combined wind and solar facilities anywhere in the world” that could provide so-called “baseload” power.

However, Robert Eye, the intervenors' attorney, said that wind and solar technology were “advancing on an almost daily basis.” The intervenors in the licensing process are Public Citizen, Sustainable Energy and Economic Development Coalition, True Cost of Nukes and Rep. Lon Burnham, D-Fort Worth.

Opponents to the expansion also had argued that Luminant's environment report didn't adequately address concerns about Comanche Peak's ability to contain a cascading catastrophic radiation leak between the two older reactors and the proposed new ones. Frantz countered that the scenario was “remote and speculative” but said that Luminant did assess “simultaneous accidents in all four units.”

In a statement after the hearing, Eliza Brown, a clean energy advocate for the Sustainable Energy and Economic Development Coalition, said all it takes is “one serious accident such as a meltdown or terrorist attack on a spent fuel pool to result in catastrophe,” including deaths, cancers and birth defects from radiation releases.