As forecast in our previous blog post on the NRC’s continuing commitment to Open Government, the agency has just published another key set of data – commercial nuclear power plant performance indicators — to the Data.gov website.
Part of the agency’s Reactor Oversight Process (ROP), these performance indicators are directly linked to the NRC’s mission. The ROP includes seven cornerstones of safety that focus on the licensee’s ability to operate the plant safely, to respond promptly and appropriately to emergencies, to protect plant workers and the communities and to protect against the design-basis threat of radiological sabotage.
Within each cornerstone, a broad sample of data on which to assess licensee performance is gathered from performance indicator (PI) data submitted by licensees and from the NRC’s inspections. The PIs are not intended to provide complete coverage of every aspect of plant design and operation, but are intended to be an indicator of performance within the related cornerstone.
Data submitted by each licensee is used by the NRC to calculate PI values. These values are then compared to objective thresholds to determine the performance band associated with those values. The bands are color coded.
Plant data for a PI that falls within the “green” band indicates licensee performance is within the expected range. The “white” band indicates that performance is outside of the expected range and can be characterized as of low to moderate safety significance, but performance remains acceptable. Performance in the “yellow” band indicates a more significant decline in performance and can be characterized as being of substantial significance. Performance is considered acceptable, but a reduction in safety margin exists.
Performance in the “red” band indicates a very significant decline in performance. Changes can be characterized as being of high safety significance. Performance may be acceptable with a significant reduction in safety margin or may be unacceptable.
PIs are a way of obtaining performance information in each of the cornerstone areas. They provide an indication of problems that, if uncorrected, may increase the probability and/or the consequences of an “off-normal “event. Since not all aspects of licensee performance can be monitored by PIs, some safety significant areas are assessed through inspection.
Reporting of PI data to the NRC is a voluntary program in which all operating reactor plants participate. Once the data is confirmed by the NRC, they are entered into the Reactor Program of quarterly machine-readable data beginning in the third quarter of 2009 through the second quarter of 2011. New data will be published quarterly in the month following the close of each quarter.
Bill Cartwright Technical Assistant Office of Nuclear Reactor Regulation
U.S. NRC Blog 
After Fukushima Incident, nuclear reactors should be banned
In establishing the ROP, site specific performance indicators (PIs) were identified as potential sources of information for the reactor oversight process. Licensees committed to providing these indicators (voluntarily) to the NRC in lieu of a regulatory requirement. This was a more efficient way of getting more data from licensees than through the regulatory rulemaking process.
The NRC does inspect licensee programs to validate that the PI data provided is accurate. If licensees do not submit the PI data, the NRC has the option to increase inspections and oversight activities to compensate for information not provided.
“Reporting of PI data to the NRC is a voluntary program in which all operating reactor plants participate.” Why is the reporting NOT mandatory?