Note:

1. Note: The examples are based on quick recollections from the memory of M. Abdou. They are only examples and are not meant as a full documentation of all contributions to Chamber Technology Research. M. Abdou, Handout for VLT-PAC Meeting, 2-25-03 Examples of Past (since the 1970’s) and Recent Achievements by the Chamber Technology Program and their Tremendous Impact on Plasma Physics Research, on other Fusion Technology Programs, and on Fusion Energy Development.

2. “Why Now?!” • It is not just needed now! • It was needed 30 years ago! • It was started 30 years ago! • It would have been impossible for the fusion program to make the progress we have made without Chamber Technology Research over the past 30 years. • No Credible plans for future fusion development are possible without Chamber Technology Research NOW. • One way to understand “why now” is to learn how Chamber Technology Research was crucial in making progress over the past 30 years. Why Chamber Technology Research Now?

3. Since the Early 1970’s, Chamber Technology Research has had a Fundamental and Major Impact on: • The Direction and Emphasis of Plasma Physics R&D • The Direction and Emphasis of Other Fusion Technology Programs • Identifying and Resolving Critical Issues in Fusion, many of which are “Go, No-Go” issues • Shaping our vision today of a burning plasma device and fusion power plant This impact is illustrated by some “historical” examples next.

4. Examples of Chamber Technology Achievements and Their Impact on Plasma Physics and Fusion Technology • 1970-74(Samples only: Mostly at Univ. of Wisconsin) • First Recognition of the crucial importance of CT to conceptualizing what a fusion reactor is like. CT was the first group to be formed. • Neutronics Research showed the need for advancing neutron transport models and codes for high energy fusion neutrons (could not use diffusion used in fission). Began Major effort on neutron/photon transport and nuclear data to provide codes that have been essential to predicting the radiation field (used today in ITER, design studies, and all fusion research). • First tritium-breeding computation that showed “DT fusion has the potential to breed its own tritium (under certain conditions): an essential requirement for viability as an energy source”. • Concluded that vacuum vessel must be outside the blanket (most serious consequences on ultimate practicality of fusion power: failure in FW/B require device shutdown). The reliability issues that we have to resolve over the next decades are associated with this “only choice” decision.

5. Examples of CT achievements/impact (1970s cont’d) • Developed detailed neutron reaction kinematics model • led to calculation of energy release in the blanket per DT fusion neutron as ~ 16MeV (as opposed to fission models that predicted 28MeV!!!) • led to realistic atomic displacement model necessary for the Material Program to study radiation effects in materials (as opposed to the “fission-imported” models which produced erroneous results when applied to the fusion environment) • CT-developed Neutron transport models, and neutron-interaction codes were used to show that “certain structural materials, such as steels, can be irradiated under certain conditions in fission reactors to simulate radiation effects in the fusion environment”. “This was the crucial work that opened the way to starting a meaningful material development for fusion”-statement by Zwilsky, Head of Fusion Materials Program in the 1970s.

6. Examples of CT achievements/impact (1970s cont’d) • CT Pioneering research on radiation shielding in 1974-77 led to • Reducing ΔBS (in board) in Tokamaks from 2m to 1m • resulted in major reduction in the size of the first designs of burning plasma experiments (EPR, TNS, FED, INTOR). The same results were used in ITER. (The physical volume of ITER would have been three times larger!!) • led to major improvements in vision for reactors. Major contributor to enable advancing from UWMAK-I (R=13m) to attractive ARIES designs (R~6m) • Developed fundamental correlations for radiation effects and design limits in superconducting magnets (insulator, superconductor, stabilizer). These correlations are essential for any design (used in ITER, reactor studies, etc.)

7. Examples of CT achievements/impact (late 1970s and early 1980s) • CT research was a driving force in initiating a US program on “RF plasma heating” • CT research results on the difficulties of shielding and maintaining line-of-sight neutral beams provided a key motivation to initiate the “RF” technology program in the late 1970’s (see John Clarke) • CT research at ANL provided the first experimental evidence that tritium could be extracted from lithium in the 1970’s. (It was critical to show that we could extract the tritium we breed) • The TRIO experiment by ANL in a fission reactor in the early 80’s provided the first experimental evidence of in-situ tritium release from solid breeders ceramics (critics were telling us “you can not get tritium out of glass”)

8. Examples of CT achievements/impact (early 1980s cont.) • CT Research was the “driving force” behind initiating plasma physics research on steady state plasmas • CT models and analysis in the 1970s quantified the adverse effects of pulsed plasma on the first wall/blanket (e.g. fatigue life). • CT researchers pushed for steady state design in STARFIRE (1979-80) • Despite initial reluctance by plasma physicists, a very large part (50%?) of world plasma physics research today is on “steady state” (ARIES studies also pushed the need for steady state and worked with plasma physicists to identify efficient current drive methods. The physics program is getting a lot of help, direction, and leverage from all areas of technology!!!) • Dr. Masaji Yoshikawa, former president of JAERI, stated recently that “It was a presentation by Abdou (CT Researcher) in 1982 at JAERI about the serious effects of plasma pulsing and the need for steady state that completely changed the direction of our experimental plasma physics program”

9. Examples of CT achievements/impact (1980s cont.) • CT research on disruptioneffects greatly influenced plasma physics research • In the early 80’s CT researchers developed models to predict the effects of disruptions on first wall and divertor (vaporization, melting, EM forces, etc.) • These models first used in the INTOR study had a major impact on INTOR, ITER, and other studies. It led to the understanding that reactors should have no disruptions. • As a result, Physics research on disruptions intensified. • One often cited motivation for stellerator research and construction of NCSX is “in case we can not avoid disruptions in tokamaks”

10. Examples of CT achievements/impact (1980s and 1990s cont.) • Joint US-JAERI Program on Integral Neutronics Experiments (1984-94) provided results, tools, and methods absolutely critical to fusion • Ingenious experimental technique development allowed the utilization of a “point” neutron source with only 5x1012 n/s as a “line source” to simulate radiation field and nuclear responses (tritium breeding, nuclear heating, radioactivity, decay heat, gas production) in “mock up” assemblies of first wall/blanket/shied. Many critical results: • uncertainty in tritium breeding due to nuclear data and calculational methods is 15% (in simple geometry, non-heterogenous assemblies) • Significance: ruled out a variety of material combinations and blanket concepts, showed the need for use of neutron multiplier in most concepts [Remaining issues that can be addressed only by testing in fusion devices: uncertainties due to heterogeneity and complex geometry] • First experimental verification of the validity of the Nuclear Heating theory/models developed in the 1970’s • Derived “safety factors’ for use in engineering design of radiation shielding in ITER and all reactor designs • Showed large discrepancies/errors in radioactivity and decay heat calculations

11. Examples of CT achievements/impact (1980s and 1990s cont.) • BCSS (1982-1984) and FW/B/S Program (1980’s) • Provided Conceptual Designs and Selected Primary Blanket Concepts • launched many R&D programs on transient EM loading, LM-MHD, tritium migration, self-healing coatings, etc. • FINESSE (1984-1987) • - Most Comprehensive Study on Fusion Nuclear Technology • - Major Impact on the World Program: • Provided the basis for FNT R&D facilities in Japan, EU & US • Identified a “Two-facilities” pathway as optimum approach for fusion development [one for physics (large size, low fluence) and one for technology (small size, high fluence)]. The technology device is what was named later as VNS (and now CTF). • Provided incentives for alternative confinement concepts, e.g. ST, and low-Q advanced tokamaks as effective approaches for VNS (CTF) • Pioneering and Comprehensive Dynamic Fuel Cycle Modeling • - Pioneering modeling that identified the permissible physics and technology parameters to satisfy tritium self sufficiency (e.g. tritium fractional burn-up in plasma, reliability of tritium system) • - Served as the basis for ITER and many R&D programs. (A UCLA Ph.D. student was invited by ITER to apply the code to ITER.)

12. Examples of CT achievements/impact (cont’d 1980’s and 1990’s) • VNS and HVPNS (1993-1996) • Most Comprehensive analysis of the requirements on fusion testing facilities (burn length, dwell time, wall load, fluence, availability, etc.) • Identified and quantified reliability/maintainability/availability issues and R&D strategy • Provided effective approaches to VNS; sparked world interest • IEA initiated a study in 1994 on VNS, called HVPNS. A scholarly, comprehensive paper was published in Fusion Technology (January 1996) by key scientists and engineers from the world program confirming US results on testing requirements and the effectiveness/importance of VNS. This work/publication has been studied by scientists, engineers as well as world technical leaders and policy makers. It was a critical input to the new US 35-yr plan and including CTF. • Leadership on ITER Technology Testing and Design of CT for Basic ITER Device (1987-1997) • A US CT Researcher was asked to lead the ITER Technology Testing Program. • CT Research in the US had major influence on the overall design and mission for ITER (e.g. neutron wall load, plasma burn/dwell time, steady state requirements were based on the US CT research) • US CT Researchers played a leading role in the design of the Chamber components of ITER. • Liquid walls advanced in the late 90’s as a power handling technology ignited debate in physics community about low vs. high recycling regimes and possibility of new, exciting plasma-confinement regime

13. 1997: The “Transition Year” • Environment in 1997 • The prevailing mood in the technology community was dominated by “pessimism” and frustration (e.g. Chamber Technology in ISFNT-4, April 1997, Tokyo) - Budget Cuts in the US - Technical limitations of conventional blankets - Predicted High cost and long time for testing & development in fusion facilities • The US developed a Restructuring Plan (Leesburg, FESAC, OFES, etc.) - Emphasis on Science and Innovation • The US Chamber Technology community had intensive discussion for restructuring. • (Independently and about the same time frame) Letter (1/16/98) from 23 Senior US Scientists to Dr. Anne Davies encouraging research on innovative high power density concepts (“we believe that it is timely for the technology side of OFES to consider a new focus to develop first wall/blanket schemes which can demonstrate high heat and neutron fluxes”)

14. CT Research over the past 5 years was a result of the Major Redirection/Restructuring of 1996/97 • The blanket program that focused on traditional concepts was mostly eliminated (reduced from annual budget of ~ $6M to ~ $1M) • A new strategic pathway for Chamber Technology was developed to reflect the new restructured programs and goals: • - Focus the greater part of resources on exploration of INNOVATIVE concepts with emphasis on understanding and advancing the underlying phenomena and engineering sciences • - Provide a smaller part of the resources to international collaboration on selected R&D areas for EVOLUTIONARY concepts in order to: a) gain access to much larger R&D programs, and b) learn the actual technological limits, which is essential to our endeavor to extend these limits • DOE and the Community (VLT, Snowmass, etc.) agreed on initiating APEX (and ALPS) in 1998

15. US Chamber Technology Program: Current SUB-ELEMENTS • 1. APEX (see website: www.fusion.ucla.edu/APEX) • - Innovative (revolutionary) concepts, Advance underlying science(s) • - US multi-institutional, multidisciplinary team with voluntary international participation • 2. Material System Thermomechanics Interactions • - Modelling and experiments for ceramic breeder/Be/structure thermomechanics interactions • - Framework: IEA collaboration; part of US strategy to gain access to the larger international program • 3. JUPITER-II (started April 2001) • - Joint Japan-US collaboration on scientific and technical issues of common interest • - Japan pays (matches US funds) for use of unique US thermofluid and thermomechanics facilities • 4. Neutronics

16. Sophisticated and challenging numerical code development for 3-D MHD fluid flow is underway in partnership between UCLA and SBIR (HyPerComp). • World fusion program has needed 3D, complex-geometry, MHD simulation tools for liquid metal blankets (closed-channels) for 20 years and now for liquid walls (free-surface) as well. • This Predictive Capability is within our reach thanks to young out-standing fluid dynamicists in the US Chamber Technology Program. • With modest resources, the US Chamber Program has kept the USin the lead in niche areas among the much larger EU and JapanPrograms Two-phase flow past a cylindrical penetration on unstructured grid Current flow through insulator crack in closed channel MHD flow

17. MTOR, recently constructed at UCLA, is a Unique facility in the world Fusion Program (and in Broader Science) • MTOR is designed to study LM-MHD fluid flow in: • Closed channel self-cooled liquid metals, and Free-surface liquid walls • Constant or gradient magnetic field typical of MFE, e.g.tokamaks, ST… • Complex geometriesrequiring large magnetic volume (e.g. manifolds) • Test LM modules prior to insertion in plasma devices (e.g. NSTX) B=0 Stretching and breakdown of two-dimensional MHD surface wave structures Bmax= 1.2 T

18. 0 ft 5 ft 10 ft 15 ft 20 ft 25 ft Power Controller Acrylic Flow Straightener Acrylic Water Box Mixing Tank TC Multiplexer Traversing TC Probe Polished SS304 Pipe (D = 3.5 inch) FLIHY, a facility recently constructed at UCLA, is sponsored jointly by DOE and Japanese Universities under the JUPITER-II Program • FLIHY addresses key issues and innovative techniques for enhancing MHD heat transfer in low-conductivity fluids in CLOSED and OPEN Channel Flows. • For the US Chamber Program, with its modest resources, to attract international funds is a measure of the high level of achievements and unique capabilities.(Note: Japanese funds will be lost if DOE/OFES funding stops) Straight Pipe Heat Transfer and PIV Test Section

19. Integrated FLIBE Experiment? Check & Review Check & Review Check & Review FLIHY Task Schedule for 6 year JUPITER-II collaboration FuY 2001 FuY 2002 FuY 2003 FuY 2004 FuY 2005 FuY 2006 Thermofluid Flow Experiments Facility: FLIHY-Closed (UCLA) Non-magnetic Phase Magnetic Phase Turbulence Visualization Experiments Heat Transfer Experiments Turbulence Visualization Experiments Heat Transfer Experiments Pipe flow geometries with innovative heat transfer enhancement configurations Same geometries as 2001-03 with magnetic field Continue with heat transfer, or another option Continue with MHD, or another option? Flibe Loop, or another option?

20. FLIHY is a dual-use facility utilized to study free surface hydrodynamics and heat transfer for liquid walls and solid walls • New heat transfer experiments underway with span-wise cylinders • New curved test section ready for construction Heat Flux Flow Water Film flowing under IR heater

21. Be pebbles of 2 mm diameter are used. The bed packing factor is 59 %. Interface conductance as a function of the bed mean temperature Beryllium pebble Li2O ceramic breeder Zero external pressure SiC disk Temperature(C) 50 100 150 Chamber technology material system thermomechanics interaction study provides fundamental data necessary prior to irradiation experiments. Also provides Important Links to International Programs • The research involves interactions with FZK, JAERI, CFFTP, CEA, and JA Universities. FZK and JA provided UCLA (at no charge) with breeding materials. • Allows the US, through modest investments, to gain access to much larger international programs.