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RADTRAD-NAI Introduction

Updated April 2019

RADTRAD-NAI is Zachry's version of RADTRAD, a computer code developed by the NRC for radiological dose analysis. The code is suitable for dose analysis under the new Alternative Source Term (AST) Guidelines (NUREG-1465) as well as the TID-14844 Guidelines.

Simplified RADTRAD-NAI Control Room Model
RADTRAD-NAI is available to customers as a local installation or via the Internet using a web-based interface. Zachry 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 both file submittable of input or 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.

The code was developed, verified and validated under Zachry's 10CFR50 Appendix B QA Program. Zachry provides continued maintenance of the code under the same QA Program, including error reporting.

Improvements in the web-based code include the following:
  1. Correction of identified errors in RADTRAD, as described in our Error Report to the NRC.
  2. Addition of capability to track pH level in suppression pools/sumps.
  3. Addition of capability to vary the free volume in a compartment with time (e.g., to account for water level variation in steam generators).
  4. Addition of capability to delete compartments, flow paths, etc. with the web-based GUI.


Please give us a call or email us. For more information please contact Analysis Division support at naisupport@zachrynuclear.com, or directly to Anita Gates, or Steve Winter. The Analysis Division contact list is here, including phone numbers.