RADTRAD-NAI™ has been developed and maintained over 15+ years by NAS Engineering, Inc. (formerly Numerical Applications, Inc.). It has been used for licensing, safety, and operating analysis of nuclear power plant postulated accident scenarios. RADTRAD-NAI includes modeling capabilities for intricate compartment and pathway configurations, filters, piping, and nuclide removal mechanisms such as natural deposition.

NAS is the developer of the RADTRAD-NAI computer code and maintains, modifies, and supports the RADTRAD-NAI code for users. The code was developed, verified and validated under NAS's 10CFR50 Appendix B QA Program. NAS provides continued maintenance of the code under the same QA Program, including error reporting.

RADTRAD-NAI is a descendant of the NRC released RADTRAD Version 3.01 developed by the Accident Analysis and Consequence Assessment Department at Sandia National Laboratory (SNL) for analysis of the potential radiological releases of nuclear power reactors during postulated accidents. RADTRAD-NAI extends the capabilities of the original code with new features, improved output files, and increased user-friendly features.

RADTRAD-NAI is available to customers via a web-based interface. NAS maintains a controlled version of RADTRAD-NAI on a central server. Each individual customer accesses this controlled version directly through the Internet using a web browser for input and output. The web input interface offers the ability to upload input files or use a form-based user interface for input of data. Customers no longer need to maintain the software on their own servers or personal computers. There is no longer a need for customers to check versions or ensure that they have loaded the latest version of the software.

RADTRAD-NAI has been benchmarked against:

• Amendment No. 211 to Facility Operating License No. DPR-26 for Indian Point Nuclear Generating Unit No. 2
• Virginia Electric and Power Company Surry Power Station Units 1 and 2 Proposed Technical Specifications and Bases Change
• Alternate Source Term Implementation submitted April 11, 2000
• GGNS Pilot Full-Scope Application of NUREG-1465 Alternative Source Term Insights, LDC 1999-082 submitted January 21, 2000
• Amendment No. 103 to Facility Operating License No. NPF-58 - Perry Nuclear Power Plant, Unit 1 (TAC NO. M96931)