TerraPower

Sector: Advanced Nuclear Energy – Natrium Reactor Program

Scope: Technical Review and Risk Analysis of Pump Designs for High-Capacity Sodium Systems

Overview

As TerraPower advances its Natrium Reactor, one of the most promising sodium-cooled fast reactor designs in development, ATLM-Global was engaged to conduct several expert reviews of past reactor-relevant sodium pumping systems to build a list of Lessons Learned including:

1) Compare fundamental alternative means of pumping sodium, 

2) Identify historical successes and performance issues, and 

3) Apply the review findings in on-going pumping system design reviews.

The reviews focused on both the technical feasibility and mechanical risks of pumping systems to meet Natrium’s unique flow and performance requirements.

Challenge

Large sodium pumping system technology in the West is almost dead, and reviving it relies heavily on understanding the successes and problems of many systems that are no longer active, poorly documented, or for which the details of their operating history have not been shared.  The volume of known issues, however, and their seriousness, measured in days of delay in reactor operation, is enormous. 

ATLM-Global was brought in to provide a comprehensive review of these issues including pump trips, pump damage, pump failures, pump component redesigns and refabrication, and pump removals for repairs; all resulting in either a restricted operating envelope or unscheduled plant shutdowns, loss of full power reactor operating time, and extra expense. 

This review identified critical engineering challenges:

• Eliminating Manufacturing Defects‍
• Understanding and eliminating Documented Failures in:‍
  
  • Thermal Distortion
  • Mechanical, Hydraulic and Tribological Domains
  • Chemical/Corrosion Issues
  • ‍Others

• Evaluating the lack of Full Experimental Validation for pump behavior during:
  
  • Preheating and sodium fill
  • Speed scans over wide ranges of temperatures and loop resistance
  • Steady-state and thermal transients
  • Endurance tests
  • NPSH performance and cavitation tests
  • Automatic flow control performance
  • Speed control testing
  • Frequency response tests

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Our Role

ATLM provided a detailed technical analysis of hundreds of relevant documents, focusing on:

• Documented cases
• Clear, concise takeaways
• Operating Issues and Lessons Learned
• Technology/Infrastructure Readiness
• Pump Technology Readiness Analysis/Assessment

Deliverables included:

• Several comprehensive reports

Results & Impact

Clarity on Technology Readiness: Helped TerraPower evaluate the feasibility of pumping system alternatives
Nuanced Risk Positioning: Provided Sodium Pump Vendor Market Survey
Global Timeline Snapshot of Pump Failures: For 19 plants, spanning 6+ decades, a granular failure chart captured the scope of the issues

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Conclusion

Large-scale pumping systems for sodium-cooled reactors push the boundaries of mechanical design, material compatibility, and resistance to thermal transients. ATLM-Global’s consultation with TerraPower ensured that engineering decisions were grounded in both functional requirements and empirical scrutiny — providing a more secure path forward for a critical reactor subsystem in one of the world’s most advanced nuclear programs.