photo by Jim Ashley
The Nuclear Regulatory Commission is increasing its oversight of Unit 1 at the Sequoyah nuclear power plant as a result of the frequency of unplanned shutdowns the plant has experienced. The Sequoyah plant is located near Soddy-Daisy, about 16 miles northeast of Chattanooga, and is operated by the Tennessee Valley Authority.
After its quarterly review of plant performance in October, the NRC updated its assessment of Sequoyah Unit 1. That evaluation consisted of a review of performance indicators and inspection results. The NRC review found that Sequoyah Unit 1 crossed the green-to-white threshold for the “unplanned scrams per 7,000 critical hours” performance indicator. This was due to one trip in the first quarter this year and three trips in the third quarter.
“Overall, the Sequoyah plant is operating safely,” said NRC Acting Region II Administrator Len Wert. “However, these shutdowns point to potential performance issues and we want to ensure that TVA addresses them appropriately.”
The NRC will conduct a supplemental inspection to provide assurance that the causes of the shutdowns are understood, to identify the extent of those causes, and to ensure TVA’s corrective actions are sufficient.
The NRC evaluates inspection findings and performance indicators at commercial nuclear power plants with a color-coded system which classifies them as green, white, yellow or red, in increasing order of safety significance. As the significance increases, the NRC heightens the level of oversight for that plant including additional inspections. If a plant takes appropriate corrective actions and improves safety performance, the agency returns to its normal, but still extensive, inspection schedule.