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Lessons Learned on NBSR Licensing Actions



Dagistan Sahin, Thomas H. Newton, Steven Dewey, Osman Celikten, Paul C. Brand, Lap-Yan Cheng


After the incident in February 2021, NBSR implemented three license amendment requests (LAR) to allow the restart of the reactor. The first LAR was to modify previous latch verification requirements in the Technical Specifications (TS). Originally TS required operators to perform one of the three methods, namely the elevation check, rotational check, or visual inspection for latch verification. Specifically, the first amendment revised the TSs to require a rotational check followed by a visual inspection. Even after extensive cleanup following the incident, there was potential fuel debris left in the NBSR primary systems. Hence, a second LAR evaluated the safety and operational impacts of such debris remaining within the primary system. Fuel debris was also found on several fuel elements and all of the fuel elements in core loading during the incident were deemed unusable. Therefore, the third LAR evaluated the use of a specific method to perform core loading analyses of the NBSR. This LAR includes an engineering procedure and detailed analysis methods to evaluate Alternative Fuel Management Schemes (AFMS) core loadings for the NBSR. We will present our lessons learned throughout the application and implementation of these LARs for the NBSR.
Proceedings Title
Proceedings of the 2023 TRTR-IGORR Joint Research Reactor Conference
Conference Dates
June 18-22, 2023
Conference Location
College Park, MD, US
Conference Title
2023 TRTR-IGORR Joint Research Reactor Conference


License Amdement Request, Safety Analysis Report, Nuclear Reactor


Sahin, D. , Newton, T. , Dewey, S. , Celikten, O. , Brand, P. and Cheng, L. (2023), Lessons Learned on NBSR Licensing Actions, Proceedings of the 2023 TRTR-IGORR Joint Research Reactor Conference, College Park, MD, US (Accessed June 23, 2024)


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Created June 18, 2023, Updated January 23, 2024