L. Waganer Consultant for The Boeing Company Harnessing Fusion Power Workshop 2-4 March 2009

1. Why Is Reliability, Availability, Maintainability, and Inspectability Important to the Future of Fusion? L. Waganer Consultant for The Boeing Company Harnessing Fusion Power Workshop 2-4 March 2009 University of California-Los Angeles

2. Greenwald Theme -Harnessing Fusion Power • The state of knowledge must be sufficient to design and build, with high confidence, robust and reliable systems which can convert fusion products to useful forms of energy in a reactor environment, including a self-sufficient supply of tritium fuel. • Specifically for Reliability, Availability • and Maintainability • Demonstrate the productive capacity of fusion power and validate economic assumptions about plant operations by rivaling other electrical energy production technologies.

3. The End Goal For Fusion - Produce Competitive Electrical Power • Our immediate goals are how to: • 1) assess our current technology maturity, • 2) determine our gaps, and • 3) postulate research thrusts to close the gaps • This will enable Demo to validate that the ultimate goal can be achieved with acceptable risk

4. The busbar cost of electricity is the most important factor for an electrical generating power plant. The plant must be an affordable, reliable, maintainable energy source and all of these factors are contained in the cost of electricity: COE = [CAC + (CO&M + CSCR + CF) * (1 + y)Y+ CD&D , where (8760*PE* Pf) CAC is the annual capital cost charge (total capital cost x Fixed Charge Rate) CO&M is the annual operations and maintenance cost CSCR is the annual scheduled component replacement cost CF is the annual fuel costs y is the annual escalation rate (0.0 for constant dollar and y for current dollar) Y is the construction and startup period in years PE is the net electrical power (MWe) Pf is the plant capacity factor (~ plant availability) CD&D is the annual decontamination and decommissioning converted to mills/kWhr Minor Effect (salaries, equip) Minor Effect (cost, life) Major Effect How Can RAMI Help?

5. Operational Time Availability = Operational Time + Scheduled Down Time + Unscheduled Down Time Plant Availability is High Leverage Tool - Equivalent in Importance to Power Production - • Operational Time is the power production time over a set period of time. • Scheduled Down Time is the sum of regularly scheduled maintenance periods for the power core, other reactor plant equipment, and balance of plant equipment - Related to component lifetimes, replacement schedules, and MTTR • The Unscheduled Down Time is the summation of maintenance times to repair unexpected operational failures that cause the plant to cease power production – Determined by MTTR/MTBF of all critical components

6. Availability is Determined by: • Reliability – The inherent reliability of all the power core and plant component parts to achieve a very high system reliability, (> 0.99). This means that individual components are validated to achieve extremely high levels of reliability. • Maintainability – The ability to rapidly and reliably maintain all the plant parts, especially the remote maintenance of the power core, is absolutely essential. Power core maintenance may be highly automated and likely autonomous in 50 years. • Inspectability - An examination of plant components to determine if there are any indications that components might fail in service, any reduction or increase in performance and/or service lifetime. This implies extensive pre- and post-operational examinations, along with an embedded, real-time monitoring of all operational components as a part of an integrated plant health management system that will predict and schedule preventative maintenance actions (new technology).

7. Vision of Power Core Maintenance ITER and other DT experimental facilities have, or will have, provided a wealth of remote handling experience that will be applicable to CTF, Demo, and the Commercial Power Plant However, those machines were never designed to have rapid remote maintenance to achieve very high levels of availability Conceptual fusion power plant studies have postulated two general approaches that have some promise (and a lot of difficulties) to achieve the required availability goal. A. Remove large blanket and divertor modules with articulated arms and installed rails through several large maintenance ports B. Remove complete sectors containing blankets, divertors, and hot shield/structure between TF coils and radially out through large vacuum maintenance ports.

8. A. Modular Maintenance Approach Stellarator Example Shown • Simultaneous maintenance in 3 ports • Module size limited to several tonnes • Fixed Transfer Chambers control contamination and enhance times • Mobile Transporters transfer used and new components to/from Hot Cell • Main Port is used for removing blanket and divertor modules • ECH launcher/waveguide removed • ECH port can then be used as Auxiliary maintenance port

9. Removal of Blanket Modules • Plumbing would be disconnected from inside the plumbing pipes • A mobile Extractor machine would enter the maintenance port and disconnect the mechanical attachments • Modules would be extracted from core and returned to Hot Cell • The above actions repeated for all modules • New or refurbished modules would be reinstalled and tested in-situ (repeated actions)

10. B. Sector Maintenance Approach • Requires a higher degree of integration between power core elements, power core building, and maintenance approach • Simplifies coolant and mechanical connections outside of hot shield • Allows simpler power core maintenance, but more massive elements to be moved with precision • More fluid and structural connections pre-tested in hot cell rather than inside power core

11. Example of AT Sector Replacement Basic Operational Configuration Cross Section Showing Maintenance Approach Plan View Showing the Removable Section Being Withdrawn Withdrawal of Power Core Sector with Limited Life Components

12. Sector Removal Remote equipment is designed to remove shields and port doors, enter port enclosure, disconnect all coolant and mechanical connections, connect auxiliary cooling to the sector, and remove power core sector

13. Operational Configuration • Bioshield (2.6-m-thick) is incorporated into building inner wall • Building wall radius determined by transporter length + clear area access • Extra space provided at airlock to assure that docked cask does not limit movement of other casks

14. Power Core Removal Sequence • Cask contains debris and dust • Vacuum vessel door removed and transported to hot cell • Core sector replaced with refurbished sector from hot cell • Vacuum vessel door reinstalled • Multiple casks and transporters can be used • Multiple locations can be accessed simultaneously

15. Power Core Removal Sequence • Cask contains debris and dust • Vacuum vessel door removed and transported to hot cell • Core sector replaced with refurbished sector from hot cell • Vacuum vessel door reinstalled • Multiple casks and transporters can be used • Multiple locations can be accessed simultaneously How Fast Can This Be Done In a 10th of-a-Kind Plant?

16. Shutdown Timeline Startup Timeline Shutdown and Start-up Times Must Be Minimized Each shutdown/start-up results in ~ 0.7% availability decrement Dominated by cooldown of systems and core = 2.6 days Assumes streamlined processes for core evacuation, bakeout, and coolant fills

17. Estimated Repetitive Maintenance Times for Replacement of a Single Power Core Sector • Assumes a single cask and transporter • Defines major maintenance activities • Assumes all removal and replacement activities are remote and automated • Repetitive actions require less than 1.5 days

18. One Cask and One Transporter Maintenance Times for Replacing Different Number of Sectors at a Time Note: Blankets, Divertors, and other In-Vessel Components are designed for a 4 full power year (FPY) lifetime

19. Multiple Sets of Casks and Transporters Can Improve Times Equivalent Annual Maintenance Times for Multiple Sets • At least two sets should be used (4.23 equivalent d/y) • Availability improvements by larger numbers of casks and transporters probably would not justify added cost • Spare maintenance equipment will be provided

20. Need to Establish Fusion Power Plant Availability Goals Consistent with Energy Community • All reasonably new electricity-generating plants are now operating in the 85-90% class • In 25-40 years, state-of-the-art plant availabilities will be 90+% • Fusion Power Plant (FPP) needs get to 90% or better Representative Plant Systems Availability Goals

21. What Should Be Demo’s Availability Goal? This notional graph illustrates how Availabilities have to grow through ITER, CTF, and DEMO Now

22. Summary • Achieving RAMI goals are imperative to the success of fusion producing competitive power • Designs shown are merely ideas at this point to help point the way to an integrated power plant design • Power core elements must be highly reliable and robust through simulation and test • Efficient maintenance of the power core is highly design dependent • High availabilities must be demonstrated by CTF and Demo • Demo must look like and act like the first commercial power plant

23. Recommendations • An integrated power core, maintenance system, and building design is essential to help select subsystem options for Demo and the Fusion Power Plant (FPP) • Pre-cursor facilities and thrusts must mature and validate subsystems and maintenance systems that are a part of an integrated design approach leading to Demo and ultimately to the FPP • An Integrated Plant Health Management system is necessary to predict and schedule preventative maintenance actions

24. Questions?