한국전력기술

Task 1. Consultation on LBB for Main Steam Line 

○ Material J-R Curve: The approach used to develop a J-R curve for the Main Steam Line material will be reviewed and evaluated.  Review of the history of the J-R curve determination methodology.  

Are there actual cases in the U.S. where the JM-R approach has been used?  

What is the technical background that may have led to acceptance of the JM-R approach? 



○ Extrapolation Method for J-R Curve: Review of U.S. NRC Technical reports and NUREG-1061 Vol. 3. 

State-of-the-art of fracture mechanics at the time that the J-T extension method was developed.  

Advances in J-R testing since NUREG-1061, Volume 3. 

Would current J-R testing methods invalidate use of the extrapolation method? 



○ Leakage Detection Capability: In this task, the FSAR and Technical Specifications related U.S. EPR will be reviewed and compared to the requirements in the U.S. regulations.  

Requirements for Technical Specification leakage monitoring.  

Requirements for LBB leakage monitoring, and can the two methods be different?



 ○ Welding Method for Carbon and Low Alloy Steel: The type of welding (SAW, SMAW or GTAW) is expected to affect the fracture toughness properties of welds for the main steam line.  

What are the expectations for relative fracture toughness for each of the welding methods, and which is the best?  

What are the advantages/disadvantages of the GTAW method (for both field and shop welding of piping spool pieces)? 



○ Confirmation of U.S. EPR Licensing for LDC: It has been identified that differences in leakage detection capability and the detection time frame exist in Regulatory Guide 1.45 and NUREG-1793, and that these may not necessarily be consistent with the U.S. EPR FSAR. 

 Based on the contradictions in the detection time frame, what value was finally approved for the U.S. EPR? 

 Did the U.S. NRC approve the licensing documents for the U.S. EPR regardless of the discrepancies between the regulatory documents? 



○ Current Issues in Licensing of LBB for the MSL: There has been considerable progress in licensing for new plants in the U.S. for both BWR’s and PWR’s, including the U.S. EPR, AP-1000 and the U.S. APWR.  

What are the past and current issues for licensing main steam line LBB for all plants?  

To the extent available, copies of licensing documents and correspondence, including any relief requests, RAI’s and other correspondence, will be provided. 



Task 2. Design Review Meeting 

○ This will occur after the preliminary reports of the tasks above are completed. Questions related to the main scope of the work and related issues will be discussed. 



Task 3. Final report documentation and results 

○ The final report shall include: The results of Task 1 and related items from the meeting.