Discussion of Technical Issues, TRL Definitions, and Interim Report

1. Discussion of Technical Issues, TRL Definitions, and Interim Report L. Waganer 3-4 March 2008 ARIES Project Meeting at UCSD

2. Results to be Reported • Economic Power Production • Power Core Fabrication (Waganer, Slattery (Boeing), Bromberg) • Reliable Plant Operations • Plasma Diagnosis and Control (Turnbull, Weaver, Kessel) • Plant Integrated Control (Weaver, Turnbull, Abdel-Khalik) • Fuel Cycle Control (Steiner, Sharpe, Weaver) • Maintenance (Waganer, Cadwallader, Peipert (Boeing))

3. Power Core Fabrication Issue: Development and Fabrication of Low Cost, High Efficiency, and Long-Lived Power Core Components Discussion: Fusion power cores contain complex, high-technology components and systems. These systems serve a variety of functions within a very harsh, high-temperature nuclear environment. The use of conventional manufacturing techniques is expected to lead to very expensive and unreliable fusion power plants. Modern fabrication techniques, including bottoms-up engineering design of materials and components are essential. Components considered: First wall blankets, divertors, S/C coils, IHX, tritium recovery/processing, fueling, heating/current drive, non-intrusive instrumentation, shielding, vacuum vessel, radiation-tolerant maintenance equipment

4. Power Core Fabrication TRL 1 2 3 4 5 6

5. Power Core Fabrication TRL 7 8 9

6. Plant Operations TRLs • In the course of defining the specific Technology Readiness Levels for the Plant Operations Issues, it was apparent that there was a great deal of similarity between all of the control issue topics. Therefore one TRL defitition will address: • Plasma Diagnostics and Control • Plant Integrated Control • Fuel Cycle Control • On the other hand, Maintenance issues seemed to be quite different and it will require a separate TRL definition

7. Plasma Diagnosis and Control Issue: Reliable and Stable Plasma Control (normal operations, startup, power level, off-normal events, fuel mix, impurity control) • Discussion: • All operation of current fusion facilities are experimental in nature: short period of operation, unique operations, no steady state. • Need to develop plasma operations and control for reliable and stable operation. • The plasma must be well understood and characterized and it must be demonstrated that events that might cause catastrophic failure of power core components would be essentially non-existent. • Must be able to control plasma at low power levels for startup and residual heat removal, at a programmed rate of increase from startup to full power, and intermediate long-term partial power operations. • Likely accommodate highly autonomous control requiring a minimal number of control room operators for normal operations as well as maintenance operations.

8. Plant Integrated Control Issue: Reliable and Stable Plant Integrated Control (system interaction, control autonomy, knowledge based control, regulatory interaction, power grid interaction) Discussion: All operation of current fusion facilities are experimental in nature with a federated control architecture with minimal central control. Each subsystem operates independently with operating parameters sent from the central command authority. A centralized system is needed to actively control all systems to optimize the plant operation. As the central control system acquires more system knowledge, it can refine its ability to fine tune and optimize operations with more autonomy and less hands-on operator interaction. Control authority will also optimize grid requests. In addition to the normal operations, integrated control is needed during maintenance periods and off-normal events. Incorporation of system health monitoring and predictive capabilities to determine the state of health of all plant systems and predict when maintenance or replacement actions are required. The ability to predict wear-out and incipient failures is assumed to continue to be improved. Components controlled: Plasma, FWB, shields, heat transfer media, S/C coils, tritium recovery/processing, fueling, heating/current drive, maintenance equipment

9. Fuel Cycle Control Issue: Reliable and Stable Fuel Cycle Control (startup tritium, steady-state inventory, production rate, permeation) Discussion: The fuel control is system is one of the better developed and matured fusion systems. TSTA has pioneered many of the fuel processing elements and subsystems. All past and present experiments have had to process and handle plasma fuels. The larger facilities have extended into the use of tritium. ITER will field a state-of-the-art fuel cycle system. What is needed is to push the system capability, reliability, and cost factors to those required for commercialization. Its control system has to be highly interactive and responsive to the central plant control system. Tritium inventory and production rate will be dependent on the institutional environment at the time (local power producer infrastructure, national infrastructure, and local/national governmental regulations. Components considered: Fuel injectors, vacuum pumps, exhaust handling, heat transfer media processing, isotope separation, storage media, atmospheric tritium recovery

10. Safe and Reliable Control TRL • Plasma Diagnosis and Control • Plant Integrated Control • Fuel Cycle Control 1 2 3 4 5 6

11. Safe and Reliable Control TRL • Plasma Diagnosis and Control • Plant Integrated Control • Fuel Cycle Control 7 8 9

12. Maintenance Issue: Reliable and Efficient Maintenance (Power core, hot cell, fuel handling, waste handling, other remote, other plant) Discussion: Granted, fusion has developed the capability to remotely handle irradiated power core elements, quite successfully for experimental facilities. ITER increases the size of the components being handled, with the capability to assemble and disassemble the entire power core. But, maintenance operations are very slow. Maintenance times must be reduced by more than a factor of 10 and perhaps 100. Man-in-the-loop must be replaced with autonomous maintenance actions. This is faster, more predictable, safer, and less prone to radioactive human exposure. These operation will include the power core, hot cell, fuel handling, waste processing, and any other radioactive or dangerous area. Scheduling of maintenance actions will be very important when integrated with predictive health management. Components considered: First wall blankets, divertors, heat transfer and transport, tritium recovery/ processing, fueling, heating/current drive, non-intrusive instrumentation, shielding, vacuum vessel, fuel processing, waste handling, and radiation-tolerant maintenance equipment

13. Maintenance TRL

14. Maintenance TRL

15. Next Actions • Accept comments on Issues and TRL definitions and gather inputs from TWG experts on refining Issues/TRLs • Evaluate the subsystem design approaches as to their Technical Readiness Levels • Some elements of the Interim Report have been written, however they need to be rewritten based on the input obtained in this meeting.