Radioactive Water Leak Forces Nuclear Power Plant Shut Down

The Comanche Peak nuclear power plant near Fort Worth was shut down after a leak of radioactive water, leading to government scrutiny of the utility's plan for finding such leaks.

Comanche Peak nuclear power plant is a two-unit nuclear-fueled power plant located four and a half miles northwest of Glen Rose in Somervell County and about 80 miles southwest of downtown Dallas. The plant is owned and operated by TXU and has an operating capacity of 2,300 megawatts (two 1,150 megawatt units).

Operators shut down plant well before leakage exceeded federal guidelines, TXU spokesman David Beshear said Tuesday. They have since repaired leaking and corroded lines, he said.

"There was never a danger to the safety of the plant, the safety of the employees or the safety of the public," he said.

A report by Nuclear Regulatory Commission inspectors said radiation monitors inside the plant's Unit 1 sounded alarms after recording high radiation readings on Sept. 26.

Radiation levels peaked six more times before operators shut down the reactor two days later, the inspectors said.

The leak was found in a small tube carrying radioactive water in one of four generators that make steam to turn the reactor's electric turbines.

The utility's own report to the NRC said a subsequent TXU check found corrosion in 667 other tubes in Unit 1, but none was leaking. That number, according to TXU, represented more than 3 percent of the tubes.

NRC spokesman Roger Hannah said an inspection of the plant focused on Comanche Peak's system for finding and responding to leaks."What we're interested in is whether they should have picked up on this earlier," he said. Federal regulators who inspected the plant plan to discuss their findings with TXU managers Dec. 10. The meeting will be open to the public.

The utility said it was the first unplanned shutdown of the plant near Glen Rose, which returned to service Nov. 11.

David Lochbaum, a nuclear safety engineer with the nonprofit Union of Concerned Scientists, said the leak could have quickly developed from debris in the water or over time if corrosion was overlooked in routine maintenance.

"If it was missed and they had the opportunity to prevent this in the past and missed it, that's one thing," he said. "But if it happened randomly, then there was nothing they could do to prevent this."

Lochbaum said about a dozen plants have shut down in the past decade because of leaks.

"It doesn't happen very often," he said.

The Davis-Besse nuclear power plant near Toledo, Ohio, has been shut down since February after acid nearly ate through a 6-inch-thick steel reactor cap.

The leak discovered in March was the most extensive corrosion ever found on a U.S. nuclear reactor and led to a nationwide review of all 69 similar plants. A second, smaller hole was found later at Davis-Besse.

The Comanche Peak leak occurred in one of four steam generators that make steam to turn electric turbines.

Small tubes carry water heated by the reactor's radioactive core into a heat exchange system designed to pass the reactor's heat into the water that makes the steam. Radiation can leak if a tube is cracked.

Tube corrosion, but not leaks, were found in previous inspections at Comanche Peak. The plant's Unit 1 received its full-power operating license in 1990. Unit 2 was licensed in 1993.

David Ritter, a policy analyst with the watchdog group Public Citizen, called the September leak a "serious problem," because it could have triggered leaks in other high-pressure lines.

Reducing corrosion is one reason for planned changes in the type of nuclear fuel that the plant uses and in the repair method for damaged tubes, according to company documents filed with the NRC.

The plant has approximately 1,300 employees.