Unit 1 at the Prairie Island nuclear plant in Minnesota faces tougher regulatory scrutiny after inspectors found it had left a radiation detector inoperable for 10 months.
On Tuesday, the Nuclear Regulatory Commission issued the plant a notice of violation related to the 1R-50 shield building high-range vent-gas radiation detector that stopped working in July of 2011.
Before the NRC came to its decision, plant owner Xcel Energy argued in a conference with regulators that the issue was not as significant as the agency suggested, and that because the equipment's sample pump still worked, staff could take necessary dose rate measurements within 15 minutes. The agency, though, found that a study illustrating the procedure "did not consistently demonstrate that (plant) staff could classify a site area emergency, RS1.1, or a general emergency, RG1.1" without the detector, according to NRC documents.
The agency issued a white finding of low to moderate safety significance for the violation. It will result in supplemental inspections to assess emergency preparedness issues, the NRC said in a release. The detector is now functional.