ITER test plan for the solid breeder TBM Presented by P. Calderoni March 3, 2004 UCLA

The unit cell strategy as a time staged, low cost option for the US solid breeder test plan 3 unit cells in EU HCPB TBM mm x 211 mm x 650 mm ¼ port sub-module design development will continue for possible integrated “act-alike” testing in high duty D-T phase No need for independent structural design / verification Simplified interface requirements (He in / out, T analysis) Focusing on relevant technical issues

Testing strategy calls for different issues to be addressed aligned with ITER operational plan H-plasma D-plasma Low Duty D-T High Duty D-T First wall structural response and transient EM/ disruption tests Neutronics and tritium production rate prediction tests Tritium release, thermomechanical interaction and design evaluation tests Initial study of irradiation effects on performance Neutronic test unit cell Thermo-mechanics test unit cell Main difference is breeder layer toroidal dimension, which determines T gradient Coolant flow conditions (unit cell operational T) are varied to address different issues Breeder Beryllium Coolant plates Unit cell wall in 100 C in 300 C out 300 C out 500 C

¼ port submodule could be implemented instead or along with unit cells Unit cell strategyEM-TBMNT-TBMTM-TBMPI-TBM ITER Master ScheduleHH and DDEarlier DTDT ITER Operational Year Delivery Year-2258 Ancillary Equipments Helium LoopTo Share Ancillary Equipment Tritium ProcessingTo Share Instrumentation in Port AreaICC, OCM, DAS TMS, ICC, OCM, DAS Number of units in EU HCPB TBM3333 Total Helium Mass Flow Rate [kg/s] 0.1 Helium Pressure [MPa]8888 Helium Pressure Drop [MPa]< 0.02 < 0.01 – 0.05 Helium inlet/outlet temperature [ o C] 300/500 or 100/ /300300/500 Design Maximum temperature [ o C] FW Beryllium (2 mm)< FW Structure< Coolant Plate Structure< Beryllium Pebble Bed300 (DD) Ceramic Breeder Pebble Bed350 (DD) Helium Purge Gas Pressure [MPa]NA 0.1 Total Helium Purge Gas Flow Rate [g/s]NA 0.3g/s [6 Nm 3 /s] Purge inlet/outlet temperature [ o C]NA TBD/450 Special featureInstrumented activation foil capsules ICC: Inlet coolant conditionner; OCM: Outlet coolant mixer; DAS: Data acquisition system; TMS : Tritium measurement system

Simplified interfaces at port plug within EU TBM module EU design already accommodated independent coolant line to control unit cell temperature after coolant conditioner – only interface required for NT unit cells Flow control within the 3 unit cells and independent heater can be installed in the PIC (piping integration cask) along with the separate purge He outlet for independent T concentration measurement for TM unit cells

Piping arrangements in the port area pipes are bent within the available space to accommodate thermal expansion while reducing neutron streaming PIC (piping integration cask) to house measurement and flow control systems One Integrated PIC located in Port Cell

High and low cost options share most R&D issues: Tritium Measurement System Located at PIC at Port Cell Space: 1x 1 x 1 m 3 for 2 systems optional

1 of 10 alternative cooling flow paths First wall inlet manifold (T in = 300 o C) First wall outlet manifold (also layer breeding units inlet manifold) (T= 353 o C) Layer breeding units outlet manifold (T=500 o C) Edge-on breeding units inlet manifold (1 of 2 alternative paths) T=353 o C Edge-on breeding units outlet manifold (1/2) T=500 o C Mass flow rate In: 0.9 kg/s Out: 0.82 kg/s By-pass: 0.08 kg/s Continued design effort for TM ¼ sub-module: Helium thermal-hydraulic design and parameters

Flexible support (1/4) Key (1/3) Electric connection Helium outlet Helium inlet By-pass line Breeder purge outlet Breeder purge inlet Be purge inlet Instrumentation TC instrumentations Be purge outlet common back plate Shared interfaces (with J HCPB TBM module) at port plug

First wall thermo-mechanical analysis (FEM of 5 Channel TBM Section) } 5-mm thick FW 5-Channels 5-Channel Pass Detail of the FW 940 mm 600 mm 730 mm 44.5 mm He T in = 300 o C/T out = 353 o C

Thermal Analysis Results h=5890 W/m 2 -K q’’=0.5 MW/m 2 q’’=0.25 MW/m 2 Temperatures distributions are not symmetric because of 5 passes and a non-uniform heating profile Max Temp: 523 o C

Technical issues addressed by unit cells are the same as the planned sub-module: neutronic tests are designed to perform initial check of neutronic code and data (neutron flux spectrum, tritium production and heating generation rates) Instrumented with activation foil and breeder capsules for spectrum and tritium production measurements Operated at low temperatures in order to freeze tritium Complex one- and two-D performance features for code evaluations Independent cooling and variable manifold design allows for flexible temperature distribution in the different sections of NT and TM unit cells (see hydraulic analysis)

Modified ITER Scale model Prototype model (EU design)  max = 1.75 MPa  max = 2.35 MPa  max = 0.41 mm at 21 cm  max = 0.18 mm at 15.2 cm Fixed x BC X Y Fixed Y BC Stress evolution at mid-plane of ITER scale model Pebble beds thermo-mechanic behavior and tritium release properties after long-term exposure to fusion pulsed loads will be investigated by TM unit cells Near term research work focuses on pebble bed thermo-mechanical integrity and performance under thermal heat cycles and the development of predictive capabilities to be included in FEM codes for blanket integrated analysis

Summary R&D on pebble bed thermo-mechanics and first wall helium flow hydraulics will continue as the near term focus along with ITER TBM engineering design, while ITER siting and collaborative agreements are being established. Concepts and framework required for ITER interface integration have been defined for the US solid breeder TBM program. The DDD report will be delivered. The US goal is to emphasize international collaboration among the interested parties. The design of a ¼ port integrated sub-module has already been presented and R&D continues on key issues, such as 3-D structural analysis. The unit cell approach has been developed as a time staged, lower cost option. Variable temperature distributions by means of flow control and independent T monitoring in the unit cells will allow effectively addressing scientific and technical issues for which the US community has extensive accumulated expertise. The ¼ port sub-module could be implemented in the high-duty DT phase for integrated thermo-mechanical testing.