Recent Progress in HCCB Design Analysis Ying, Alice With contributions from M. Narula, R. Hunt, S. Park, M. Youssef, W. Zhang TBM Meeting February 14-15, 2007 UCLA

Summary Efforts were carried out in the following areas: –Continued thermo-fluid design analysis for Helium coolant manifold designs (Narula) –Progress in the integrated design analysis approach –Input to FMEA –Nuclear optimization of the HCBB TBM with varying Li-6 enrichment and plan for 3-D analysis (Youssef- 10 minutes)

Basic Configuration and Partnership Scheme for HCCB remain the same as Aug HCCB Joint Partnership The proposed US HCCB sub-module will occupy 1/3 of an ITER horizontal half-port US HCCB TBM sub-module (710  389  510 mm) RAFS FW with He coolant channels He purge gas pipe Be pebbles Ceramic breeder pebbles Cooling plate

Engineering Design Analysis Emphasizes Integrated Computer Aided Engineering (CAE) Approach Preliminary effort focuses on Thermo-fluid and Structural Thermo-mechanical coupling EM and pebble bed thermomechanics integration as the next step SCTPre SCTsolver SCTpost FLDUTIL SC/Tetra ANSYS.MDL file format input to SC/Tetra preprocessor.cdb file format to input geometry and temperature load for ANSYS Thermo-fluid Analysis Velocity, Temperature, and Pressure in fluid domain Temperature in solid domain Primary and Thermal Stress Analysis Stress and Strain in the solid domain Transient and steady state thermal stress Analysis CAD modelCADthru Fix CAD model.MDL model Example Code choices for EM: ANSYS/OPERA Code choices for pebble bed thermomechanics: ANSYS/MARC

Elements in SC/T mesh : 3 million (first order tetrahederons and prisms) Elements in ANSYS mesh: 0.25 million (second order tetrahederons, etc.) In ANSYS only the solid domain is meshed with second order elements (SOLID 186). The mid-node temperature loads are interpolated during data transfer Data Transfer Between Various Physics Simulation Codes Nodal/Element Based Data Interpolation SOLID D 20-Node Structural Solid first order tetrahederons

High order element (accuracy) can not be applied in a full simulation model 16-channels model first order tetrahederons remain with reduced number of elements ANSYS Structural mesh CFD SC/Tetra mesh 3-channels model Higher order elements used with mid- node temperature interpreted

Stress and deformation calculations were performed to guide manifold design Deformation + un- deformed edges and temperature distribution first order tetrahedral elements used in the structure to restrict the number of computational nodes below 0.5 million Temperature (Body force load) and pressure surface loads as well as nodal information imported from SC/Tetra CFD code to ANSYS structural code BC: Two edges at the back clamped

Outlet coolant duct deformed significantly shape and wall thickness need to be redesigned Von Mises stress and displacement He Pressure applied to the coolant channels

Plots of Von Mises stress & displacement Plot of stress & displacement at mid-plane of side wall coolant channels FW Outlet 1/2 FW helium distributor 1/4

Plots of Von Mises Stress and Displacement on First and Side Walls FWSide Wall

Z origin

Slice show of Von Mises Stress distribution at different Z cutting planes (High stress magnitudes located at manifold plane) Maximum stress at FW Ferritic steel structural surface: 230 MPa Yield strength (  Y )at 550 o C ~ 340 MPa  p < 1.5 S m and  p +  t < 3 S m (S m = 1/3  Y )

Breeding units (4) FW cooling manifold assembly Breeding zone cooling plate manifold assembly Cap (2) FW structural panel Exploded view of the HCCB sub-module A completely assembled breeding unit to be inserted into the structural box The HCCB is based on Edge-on configuration Hot isostatic pressing (HIP) technology to join square tubes to form the FW structural panel, and fabrication of other elements such as internal cooling plates. Electron-beam, laser welding, and possibly other techniques to join manifolds to the first-wall structural panel and internal cooling plates. Be pebbles filled into places through Upper Cap

Manufacturing Process for breeder unit cooling plate is under evaluation (similar cooling plate being used in HCPB, HCLL, etc. concepts) 2 Mirrored Sections made through investment casting SC2-S Holes in top cover used for filling with breeder pebbles Breeder cover plates welded onto coolant channel parts SC2-C SC2-U Casted Channel section HIPed to bent plates Poloidal height = 590 mm Radial depth= 362 mm Plate thickness = 6mm Breeding zone width = 11 to 18 mm Weld caps length= 4 x( x2) = 3012 mm Side weld length = 2x 2x( )=2432 mm Weld length per BU= 5444mm Hip length per BU= mm 64 channels Hip length= 64 x2 x ( )= mm

Input to FMEA: Example Index ComponentTBM-BZ-distributor plate welds OP. ST. No Failure ModeLoss of leak tightness CausesDefects in manufacturing; Abnormal operating conditions (e.g.: vibrations and/or thermal-mechanical stress not foreseen by design); Fatigue Preventative Actions on Causes Test and inspection during manufacturing & assembly ConsequencesGeneration of bypass line between two BZ cooling paths; Generation of flow unbalance among the coolant channels and leading to inadequate cooling for one or more BUs; Increase of local temperatures due to inadequate cooling; Cause of coolant leak into TBM Box due to loss of leak tightness of BU Back-Cap Weld or Be Enclosure Plate-Weld; Consequences as for the "TBM-BU-Back-Cap- Weld - Loss-of Leak Tightness" or "TBM-Be Enclosure Plate-Weld-Loss-of Leak Tightness" could follow Frequency mm x 5 x10 -8 /h.m = 2.2 e-6/h Section A cover weld to front of Section A distributor plates Breeding zone manifold formed by 4 radially dividing “plates” and 2 ducts with grooves

Example List of Failure Modes with Components ComponentFailure ModeComponentFailure Mode TBM-FSWRuptureTBM-FSW-CapWeld-FrontLoss of leak tightness- He purge Plate DeformationTBM-FSW-CapWeld-RearLoss of leak tightness- He Coolant Break in internal hipping joint TBM-Upper Cap Be filling tubes Loss of leak tightness TBM-FSW-CoolChPartial or complete pluggingTBM-BU Insert/Be Enclosure plate Plate deformation TBM-FSW-BeDetachment of Be layer from FSW TBM-BU-Upper/Lower- Caps-Weld Loss of leak tightness TBM-CapRuptureTBM-BZ-front distributor closure plate-Weld Rupture/Loss of leak tightness Plate DeformationTBM FW Manifold cover plate Rupture/Loss of leak tightness Break in internal hipping joint TBM-FW coolant supply and return channel blocks Rupture/Loss of leak tightness TBM-Cap-CoolChPartial or complete plugging TBM-BZ helium coolant supply ducts-Weld Loss of leak tightness

Figure 15 View of majority of manifold systems upon assembly FW manifold total weld length (Figs: 11-14)= mm Breeding unit manifold total weld Length (Figs: 5-10)= mm BU caps + side walls (Fig. 4) = 4 x5444= 21776mm BU/FSW (Fig. 3) = 3980 mm Cap/FSW (Fig. 2) = 6600 mm Hip length FW (Fig. 1) = mm BU (Fig. 4) = 4 x mm = mm Total weld length = mm Total hip length = mm Longitudinal failure rate = 5 x10 -8 /h.m (high end) Failure rate for welds = 4.5 x10 -6 /h Hipping failure rate use failure rate for straight pipe= 1 x10 -9 /h.m Failure rate from hipping = 1x10 -6 /h

Draft Qualification program for HCCB Qualification Program ActivityAssumed Milestone Development of HCCB TSD (Technical Specification Document) 1 st Draft during preliminary design reviewDec nd Draft during bid package document completeSep Final during HCCB final design reviewDec Development of Structural Design Criteria Draft during preliminary design reviewDec Final during fabrication contract awardMar Tests and In-Service Inspections (Projected tasks and dates) Small-scale FW helium flow design verification testsDec HCCB 1/3 scale helium flow and FW heat flux testingOct Prototype fabrication starts (full scale)Apr Prototype qualification tests startMar Safety and Regulatory Support Input to RPrS dueMar Input to RFS dueJun HCCB ITER Sub-module HCCB sub-module final design reviewDec HCCB Sub-module fabrication startsDec HCCB sub-module acceptance tests startSep HCCB Sub-module delivered to Host Party Jul. 2014

Near-term tasks 1. Perform structural analysis (primary + thermal stress) to validate breeding zone manifold design 2. Develop flow distribution schemes for three sub-modules FW manifold Breeding zone manifold Flexible support (4) Key- way (3) US sub- module He coolant pipes (3): Inlet, outlet, by-pass Common Back Wall Manifold Assembly