U. S. Nuclear Regulatory Commission
Effluent Database for Nuclear Power Plants

Frequently Asked Questions
What kinds of data are in this database?
This database contains annual effluent data submitted to the NRC as part of a licensee’s annual effluent release report. Data includes radionuclide concentrations released through aqueous and gaseous effluents, volumes of liquid released from the site, and the dose calculated to nearby residents as a result of these effluent releases.

Currently the database consists of complete datasets for 2001 through 2009. Data from other years has been entered for some NPPs.

How is the data entered into the database?
The NRC receives an annual effluent release report from each NPP in accordance with requirements outlined in 10 CFR 50.36(a)(2), under the guidance of Regulatory Guide 1.21.

A database was developed using Microsoft Access based on the guidance provided in Regulatory Guide 1.21. Data from the effluent release reports is manually entered into the database, followed by a QA/QC review.

The data submitted in the effluent release reports does not always fit the format of the database exactly. In these instances changes to the data may need to be made. A list of modifications that may be made includes:

  • The database presents results within three significant figures. In instances where a plant reported more significant figures, the number was rounded to the third significant figure. For example, a plant reports a gaseous release of 6.101E-06 Ci of Iodine-131 in the 4th quarter. This value would be rounded to 6.10E-06 Ci. It should be noted that this procedure does not affect the accuracy and precision of the data given that estimated total error rates typically reported by utilities vary from 10% to 60%.
  • The symbol "NR" (Not Reported) is used to indicate that the licensee did not report specific data.
  • The symbol “ND” (Not Detected) is used to indicate that no measurable amount was found. Many reports use the symbols LLD or
  • In some cases a licensee with multiple units (e.g., 3 reactors on a site) may submit a single effluent report with a single value for the site as a whole. In these cases, the data is entered into the first unit of that NPP. No data will be entered into the other units. Efforts have been made during the data entry process to include a description of the release points to assist with identifying the source of the effluent release provided such information was included in the report.
How do I navigate the database?
Follow the links on the website to enter the effluent database. The database currently supports a report function which allows the view to view the data for a specific NPP for a specific year. A simple query function has also been included to allow the viewer to compare data from different NPPs.

Who do I contact if I have questions?
If you are from a specific NPP and find an error, please contact your NRC Project Manager and direct them to contact the Office of Research Effluent Database Manager. All other questions should be directed to the Office of Public Affairs (see Contact Us).

I don't understand all of the terminology, do you have a glossary?
A glossary of abbreviations and other common terms used throughout this database can be found here. A list of all of the radionuclides and their symbols can be found here.