September-October 2017 NPJ

Nuclear Plant Journal, September-October 2017 NuclearPlantJournal.com 49 is actively considering application to other BWRs in their fleet. Realistic evaluations utilized in the TRACG LOCA methodology along with improved margins achieved with this approach enable a better understanding of the true margin in operation. These improved margins can then be utilized to improve operational, maintenance, and licensing flexibility. For example, the extra margin gained via TRACG LOCA application could then be used to lower available system requirements for accident mitigation and relax fast start-up/opening time requirements enabling significant simplification for maintenance and limited condition operation requirements. Furthermore, in close coordination with Probabilistic Risk Analyses (PRA), either as directly providing additional margin for PRA scenarios and/or providing the licensing support through defense in-depth evaluations, TRACG LOCA application enables reducing safety classification of some of these systems. Consequently, TRACG-LOCA complements Probabilistic Risk Analyses (PRA), and its application can be used to significantly reduce core damage frequency and reduce maintenance cost. Thus, TRACG-LOCA may be applied to gain additional benefits beyond fuel savings, making it broadly applicable for plants that are not limited by LOCA. Communications With Exelon’s desire to improve the LOCA safety analysis and reduce fuel costs, a significant number of communications and outreach occurred to bring this innovation to fruition. Nuclear Fuels worked effectively with both Nine Mile Point Unit 1 and Oyster Creek stations to attain alignment for this initiative and deliver the necessary inputs for the LOCA analyses. Exelon also audited the GEH LOCA analyses for Nine Mile Point Unit 1 to ensure accuracy and that requirements were met. Exelon participated in numerous meetings with GEH and the NRC throughout the review of the Licensing Topical Reports and the 104 Requests for Additional Information. Since the NMP1 application was executed in parallel with the licensing review of the methodology, constant communication between the fuel vendor, the regulator, and the utility was instrumental to the success of this project and all future applications. These communications demonstrate effective internal and external outreach. Vision & Leadership Exelon demonstrated exceptional leadership in change management by being the first utility in the United States to implement the GEH TRACG-LOCA methodology in theNineMile Point Unit 1 and Oyster Creek core designs and reload licensings. This demonstrates effective organizational motivation to improve the safety and economics of these nuclear power plants. Exelon management and Figure 2: New Visualization of the LOCA Event. engineers were actively engaged with the fuel vendor and the NRC to resolve issues, maintain focus and schedule, and communicate the importance of this innovation. The expected measurable results were achieved with a fuel cost savings of $4.5M to date for Nine Mile Point Unit 1 with continued savings of approximately $2M per 2-year fuel cycle. An approximate $2.5M fuel cost savings for Oyster Creek is expected contingent upon market conditions for fuel. Despite Oyster Creek’s planned plant shutdown by year-end 2019, Exelon is dedicated to running the reactor safely and efficiently throughout its licensed lifetime. Contact: James Tusar, Exelon Generation, telephone: (610) 765-5818, email: james.tusar@exeloncorp.com . Figure 3: Complete Re-Analysis of all Potential Breaks.