No. IV-12-008

Contact: Victor Dricks (817) 200-1128

 Lara Uselding (817) 200-1519

 

March 15, 2012 

 E-Mail: OPA4.Resource@nrc.gov

NRC TO SEND AUGMENTED INSPECTION TEAM TO 

SAN ONOFRE NUCLEAR GENERATING STATION

The Nuclear Regulatory Commission will send an Augmented Inspection Team (AIT) to 

the San Onofre Nuclear Generating Station to review the circumstances that led to three tubes 

failing a pressure test at Unit 3 yesterday. 

Operators of the plant, located near San Clemente, Calif., shutdown Unit 3 on Jan. 31, 

after a tube leak in one steam generator was identified. Resident inspectors responded to the 

control room to monitor site activities during the incident. The unit has remained safely

shutdown and NRC has had a steam generator expert and additional inspectors at the site 

inspecting the licensee’s activities and tests of the steam generator tubes.

On Wednesday, March 14, three tubes in Unit 3 failed a pressure test indicating they

would be more likely to rupture during certain plant events that affect the pressure inside the 

steam generator. The test involves pumping water inside a tube and increasing the pressure while 

monitoring a pressure gauge to evaluate the integrity of the tube. The integrity of steam generator 

tubes is important because the tubes provide an additional barrier inside the containment building 

to prevent a radioactive steam release. Steam generators do experience some wear during the 

first year of operation but the level of tube wear at Unit 3 is unusual. 

AITs are used by the NRC to review more significant issues such as a tube failure at 

NRC-licensed facilities. The team has assumed responsibility from the resident inspectors for 

gathering information about the current condition and will travel to the site in the coming days.

The team will include inspectors from the NRC’s Region IVoffice and NRC Headquarters in 

Rockville, Md. The team will be led by NRC Region IV Branch Chief Greg Werner of the 

Division of Reactor Safety.

“An AIT is used when the NRC wants to promptly review the circumstances surrounding 

a significant issue,” said NRC Region IV Administrator Elmo E. Collins. “We want to make sure 

we understand the cause of the degraded steam generator tubes and take appropriate actions 

based on our inspection results.”

NRC NEWS

U.S. NUCLEAR REGULATORY COMMISSION

Office of Public Affairs Region IV

 1600 E. Lamar Blvd.

 Arlington, TX 76011-4511

Telephone: (817) 860-8100

Site: www.nrc.gov

Blog: http://public-blog.nrc-gateway.gov
The team will review information associated with the design, construction, shipping, 

operation, and testing of the Unit 3 steam generators. The team’s report will not contain 

inspection findings, but will identify areas for further inspection follow-up.

The NRC will hold a public exit meeting with the licensee upon completion of the 

inspection to discuss preliminary findings. The meeting will be open to interested members of 

the public and the news media, and team members will be available to answer questions after the 

results are presented. The AIT will also issue a written report within 30 days of completion of the 

inspection.

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