Recent Progress in HCCB Design Analysis

Ying, Alice

With contributions fromM. 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. 2006

HCCB Joint PartnershipHCCB 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 Engineering Design Analysis Emphasizes Integrated Computer Aided Engineering (CAE) ApproachComputer 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 model CADthru

Fix CAD model

.MDL model

Example

Code choices for EM: ANSYS/OPERACode 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

SOLID186 - 3-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 channelsFW Outlet 1/2

FW helium distributor 1/4

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

FWSide Wall

Zorigin

0.55

0.51

0.010.14

0.49

0.29 0.04 0.030.44

0.498

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 MPaYield strength (Y)at 550oC ~ 340 MPa

p < 1.5 Sm and p + t < 3 Sm (Sm = 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 configurationThe 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(11+18+362x2) = 3012 mm

Side weld length = 2x 2x(18+ 590)=2432 mm Weld length per BU= 5444mm

Hip length per BU= 185256 mm

64 channels Hip length= 64 x2 x (362+362+23)= 92628 mm

Input to FMEA: Example

Index

Component TBM-BZ-distributor plate welds

OP. ST. No

Failure Mode Loss of leak tightness

Causes Defects 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

Consequences • Generation 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 44108.3 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

Component Failure Mode Component Failure Mode

TBM-FSW Rupture TBM-FSW-CapWeld-Front Loss of leak tightness- He purge

Plate Deformation TBM-FSW-CapWeld-Rear Loss of leak tightness- He Coolant

Break in internal hipping joint

TBM-Upper Cap Be filling tubes

Loss of leak tightness

TBM-FSW-CoolCh Partial or complete plugging TBM-BU Insert/Be Enclosure plate

Plate deformation

TBM-FSW-Be Detachment of Be layer from FSW

TBM-BU-Upper/Lower-Caps-Weld

Loss of leak tightness

TBM-Cap Rupture TBM-BZ-front distributor closure plate-Weld

Rupture/Loss of leak tightness

Plate Deformation TBM 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-CoolCh Partial 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)= 14177.2 mm

Breeding unit manifold total weld Length (Figs: 5-10)= 44108.3 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) = 270528 mm

BU (Fig. 4) = 4 x 185256 mm = 741024 mm

Total weld length = 90641.5 mm

Total hip length = 1011552 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 HCCBDraft Qualification program for HCCB

Qualification Program Activity Assumed Milestone

Development of HCCB TSD (Technical Specification Document)

1st Draft during preliminary design review Dec. 2008

2nd Draft during bid package document complete Sep. 2009

Final during HCCB final design review Dec. 2012

Development of Structural Design Criteria

Draft during preliminary design review Dec. 2008

Final during fabrication contract award Mar. 2010

Tests and In-Service Inspections (Projected tasks and dates)

Small-scale FW helium flow design verification tests Dec. 2007

HCCB 1/3 scale helium flow and FW heat flux testing Oct. 2010

Prototype fabrication starts (full scale) Apr. 2011

Prototype qualification tests start Mar. 2012

Safety and Regulatory Support

Input to RPrS due Mar. 2007

Input to RFS due Jun. 2013

HCCB ITER Sub-module

HCCB sub-module final design review Dec. 2012

HCCB Sub-module fabrication starts Dec. 2012

HCCB sub-module acceptance tests start Sep. 2013

HCCB Sub-module delivered to Host Party Jul. 2014

Near-term tasks1. 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