NRC NEWS

U.S. NUCLEAR REGULATORY COMMISSION

Office of Public Affairs Region III

2443 Warrenville Road

Lisle IL 60532

Site: www.nrc.gov

Blog: http://public-blog.nrc-gateway.gov

No. III-13-008

Contact: Viktoria Mitlyng (630) 829-9662

 Prema Chandrathil (630) 829-9663

March 26, 2013

E-Mail: OPA3.Resource@nrc.gov 

 NRC CITES PRAIRIE ISLAND UNIT 1 FOR AN ISSUE

INVOLVING THE LOSS OF A HIGH RANGE GAS DETECTOR

The Nuclear Regulatory Commission staff issued a violation to Prairie Island Nuclear 

Generating Plant Unit 1 that will result in additional oversight. The two-unit plant operated by 

Northern States Power Company-Minnesota is located in Welch, Minn., approximately 45 miles 

southeast of Minneapolis.

NRC inspectors identified the violation during a December 2012 inspection. The 

violation involved the failure of the plant to maintain an effective emergency plan by not 

prioritizing the repair of a high range vent gas radiation detector. This detector is used to help 

determine if an incident should be classified as a General or Site Area Emergency, the two 

highest of the NRC’s emergency classifications. While this detector was out of service, 

alternative methods were in place that would have allowed plant staff to accurately classify and 

declare a General or Site Area Emergency. 

The utility has repaired the detector, returned it to service and has taken corrective 

actions to better assess emergency equipment failures.

“Even though the issue did not have an impact on the public, the NRC requires measures 

be in place and maintained to ensure the health and safety of the public is protected during 

certain emergency events,” said Region III Administrator Charles Casto. “We have inspected the 

plant’s corrective actions and know there were alternative means to classify these events, but we 

will conduct additional inspections to ensure emergency equipment is in working condition.”

The NRC will conduct a supplemental inspection to review whether plant staff 

understood the cause of the problems, to look at the plant staff’s ability to correctly assess and 

plan for activities involving emergency preparedness, and to assess their ability to identify and 

resolve problems with appropriate priority.

The NRC evaluates a nuclear power plant’s performance with a color-coded process that 

classifies regulatory findings as green, white, yellow or red, in order of increasing safety 

significance. After considering the information regarding this violation at Prairie Island, the NRC 
staff has characterized the inspection finding as white, or as having a low to moderate safety 

significance.

The company has until April 25 to contest the finding. The NRC inspection letter 

detailing the final determination will be publically available via the Agencywide Documents 

Access and Management System on the NRC website using accession number ML13081A503.

###

News releases are available through a free Listserv subscription or by clicking on the EMAIL UPDATES 

link on the NRC homepage (www.nrc.gov). E-mail notifications are sent to subscribers when news releases are 

posted to NRC's website. For the latest news, follow the NRC on www.twitter.com/NRCgov.