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2nd Information meeting on High Temperature Engineering -Investigation of High Temperature Reactor Materials (HTR)

Investigation of High Temperature Reactor(HTR) Materials

by

D. Buckthorpe1), R. Couturier2), B. van der Schaaf 3), B. Riou 4),H. Rantala 5), R.Moormann 6), F. Alonso 7), B-C. Friedrich 8)

� 1) NNC Ltd., Knutsford, UK� 2) Commissariat à l’ Energie Atomique (CEA.), Grenoble, France� 3) Nuclear Research and Consultancy Group (NRG), Petten, Netherlands� 4) Framatome ANP, Lyon, France� 5) European Commission, Joint Research Centre (JRC), Institute for Advanced Materials, Petten,

Netherlands� 6) Forschungszentrum Juelich GmbH (FZJ.ISR), Germany� 7) Empresarios Agrupados Internacional S A (EASA.MD), Spain� 8) Framatome ANP (GmbH), Erlangen, Germany

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2nd Information meeting on High Temperature Engineering -Investigation of High Temperature Reactor Materials (HTR)

� Overall European HTR Program� Supported through the EU Fifth Framework Program

Projects started in 2000

HTR-C CoordinationHTR-F Fuel TechnologyHTR-M Materials HTR-N Reactor Physics and Fuel cycle

Projects started in 2001HTR-E Equipment (Components)HTR-F1 Fuel technologyHTR-L LicensingHTR-M1 MaterialsHTR-N1 Reactor Physics and Fuel

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2nd Information meeting on High Temperature Engineering -Investigation of High Temperature Reactor Materials (HTR)

HTR-TN-High Temperature Reactor Technology NetworkThe general objective is to set up a European Network forthe co-ordination and management of expertise andresources in developing advanced HTR technologies,helping the European nuclear industry in designing reactorsof this type, which can withstand in the long term thecompetition of other sources of energy, while keeping avery high level of safety and offering innovative solutionsfor minimising the long lived high level wastes of the fuelcycle and for burning civil and military plutonium in aparticularly efficient way.

The primary focus is to recover and make available to the European nuclear industry the data and theknow-how accumulated in the past in Europe and possibly in other parts of the world in thedevelopment of HTR technology.

www.jrc.nl/htr-tn/

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� HTR-M Project Objectives� To develop:

– HTR Vessel materials and data in the areas of design analysis,structural integrity analysis, and materials properties under irradiatedand non irradiated conditions including tests on welds

– Materials for the high temperature regions of the HTR under simulatedenvironments for both specific areas of reactor internals (control rod)and for the turbine

– Limited work to establish graphite materials data base of availableinformation and perform work associated with graphite oxidationcovering the consequences of severe air ingress with core burning andadvanced C-based options.

2nd Information meeting on High Temperature Engineering -Investigation of High Temperature Reactor Materials (HTR)

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2nd Information meeting on High Temperature Engineering -Investigation of High Temperature Reactor Materials (HTR)

� HTR-M Project

� Vessel Materials

� High Temperature materials– Internal structures

– Turbine materials

� Graphite– Properties

– Oxidation tests

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2nd Information meeting on High Temperature Engineering -Investigation of High Temperature Reactor Materials (HTR)

� HTR-M1 Project Objectives� To substantiate :

– the alloy selection for the turbine blade material by performingmedium term creep tests and tests after aging with damage analysis& lifetime modeling to confirm suitability to long term exposure attemperature

– the graphite selection for the HTR through irradiation testing of alimited number of samples in the High Flux Reactor at Petten. Thetests will be aimed at estimation of physical and mechanicalproperties for long term exposure, establish the groundwork forcontinuation of testing on the most desirable graphites and serve toreinstall graphite irradiation and qualification methods withinEurope. Limited oxidation work on coatings.

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2nd Information meeting on High Temperature Engineering -Investigation of High Temperature Reactor Materials (HTR)

� HTR-M1 Project

� High Temperature materials– Turbine blade materials

� Graphite– Selection & Irradiation Testing

– coatings

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2nd Information meeting on High Temperature Engineering -Investigation of High Temperature Reactor Materials (HTR)

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2nd Information meeting on High Temperature Engineering -Investigation of High Temperature Reactor Materials (HTR)

� Vessel Materials

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2nd Information meeting on High Temperature Engineering -Investigation of High Temperature Reactor Materials (HTR)

� Material Issues� current & new reactors use either:

– SA508 or similar (insulated design) - LWR P.V steel

– Mod 9Cr1Mo Steel (inlet temperature vessel)

� both materials have similar strength level up to 370oC- above 450oC Mod 9Cr1Mo has a big advantage over2.25 Cr 1 Mo

� Substantial data base exists from LWR and gas cooledreactors in UK for C-Mn steels

� Mod 9Cr1Mo steel considered to have the most gapswith regard to data and fabrication experience

� Tests need to cover as-received & post weld heattreated base material and weldments

� Oxidation/carburisation vs. He purity

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2nd Information meeting on High Temperature Engineering -Investigation of High Temperature Reactor Materials (HTR)

� Structural Integrity issues

� Areas of most concern are welds� potential for failure and leaks� concerns are fracture, fatigue and creep-fatigue (Mod 9Cr1Mo)� fluctuating thermal and mechanical loads� environment (temperature, irradiation, ageing, oxidation,

carburisation)� thicker section properties

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2nd Information meeting on High Temperature Engineering -Investigation of High Temperature Reactor Materials (HTR)

� Material Issues & main concerns with respectto Structural Integrity

0

50

100

150

200

0 100 200 300 400 500 600

Temperature °C

S mt (

3x10

5 hou

rs) M

Pa

SA 516-70

SA 508

2.25 Cr-1Mo (RCC-MR)Mod 9Cr-1Mo (EFR)

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2nd Information meeting on High Temperature Engineering -Investigation of High Temperature Reactor Materials (HTR)

Country Japan SouthAfrica

Russia +others China

System (1) HTTR MSFHTR

SSFHTR

HTR-GT300

HTR-GT600

PBMR GT-MHR

HTR10

Purpose (2) Tests H+E E+DS E E E E TestsPower, MWt 30 450

600 50 300 600 265 600 10

Core Type) Block Block Block P. Bed Block P. Bed Block P. Bed

He Pressure,MPa 4 6 7 6 6 7 8 3

Core inlet,°C 395 350

550 490 550 460 536 490 300(8)

Core Oulet,°C

850950

850 950 850 900 850 900 850 900

(8)

RPV wall,°C 400 - - <350 460 300 440 -

RPV ID, m 5.5 - - 7.27 6.2 7.3 2.5

Beltline thk., mm (3)(4) 122 - - 150 - 140 200

approx100

approx

Flange thk.,mm (4)

300approx - - 550

approx - 365 670 -

Vessel mass,te (5) - - - 800

(V)<1000

(V) 600 1362(V+C) 142

Material 2¼ Cr1Mo

Mod9Cr

Mod9Cr SA508 Mod

9Cr SA508 Mod 9Cr SA516-70

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2nd Information meeting on High Temperature Engineering -Investigation of High Temperature Reactor Materials (HTR)

� HTR-M Project programme� WP1 Vessel Materials� Task 1. Review of existing RPV materials used on gas

cooled and other types of reactors� Task 2. Establish a data base for RPV steels at low and

elevated temperatures� Task 3. Tests on steel RPV welded joints: tensile /

creep , cross weld, creep / fatigue, fracture as required.� Task 4. Tensile / creep fracture tests as required on

specimens irradiated in HFR at NRG� Task 5. Synthesis of results

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2nd Information meeting on High Temperature Engineering -Investigation of High Temperature Reactor Materials (HTR)

� Vessel - results to date and next stepsresults to date� Review of materials underway� Work on Data base started - Alloys DB� Mod 9Cr1Mo steel to be irradiated in HFR� Preliminary test program established

next steps� Identification of transient bounding cases� procurement of material / welded test features� Assembling of material data for selected steels� finalise test program & test schedule� tests scheduled to begin mid 2002

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2nd Information meeting on High Temperature Engineering -Investigation of High Temperature Reactor Materials (HTR)

� High Temperature Materials

– Internal structures (Control Rod)

– Turbine (blades & discs)

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2nd Information meeting on High Temperature Engineering -Investigation of High Temperature Reactor Materials (HTR)

� Material Issues (control Rod)

� Austenitc steels established for operation up to 550 oC� temperatures ~480oC inlet to ~900oC outlet� C/C composites may be needed� irradiated He environment

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2nd Information meeting on High Temperature Engineering -Investigation of High Temperature Reactor Materials (HTR)

� Structural Integrity Issues (control rod)

� Control rod segmented containing absorbed material� freely suspended� gaps between tubes and absorber rings need to be

maintained under irradiation induced swelling� Seismic considerations

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2nd Information meeting on High Temperature Engineering -Investigation of High Temperature Reactor Materials (HTR)

� HTR-M Project Programme� WP 2 High Temperature Materials� WP 2.1 Internal Structures (control rod)� Identification of materials with high potential interest

and compilation of existing data.� Selection of the most promising grades for further

R&D effort.� Development and testing of available alloys to meet

HTR requirements� Test work concentrates on control rod cladding

materials. Mechanical / creep tests at temperatures upto 1100 oC in facility at CEA.

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2nd Information meeting on High Temperature Engineering -Investigation of High Temperature Reactor Materials (HTR)

� Results to date & next steps (control rod)� results to date� Review of possible materials started� Specification on design use

� next steps� Assembling of material data for selected materials� selection of material candidates� finalise test program & test schedule� tests scheduled to begin mid 2002

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2nd Information meeting on High Temperature Engineering -Investigation of High Temperature Reactor Materials (HTR)

� Material Issues (turbine blades & disc)� Creep and environment� blade operating temperatures of 850 to 950 oC� operating period (target 60,000 h)� sound industrial & manufacturing base� disc - defect free ingots (~1.4 m)with good forging properties:

– A286, IN 706, IN 718, UDIMET 720, ODS-MA6000

� blades - non cooled offers cheaper option– IN 713LC, M21, Mar M 004 , Mo-TZM

� Helium environment (577-900°C ) : Ni-base alloys (e.g.IN 617)chromium-rich oxide scale + microstructural changes

� coatings - e.g aluminide coatings on 713LC� impurities + Alloy chemistry (low Al/Cr, Al/Ti)

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2nd Information meeting on High Temperature Engineering -Investigation of High Temperature Reactor Materials (HTR)

� Structural Integrity Issues (turbine blades & disc)� blades� temperature distribution� creep rupture and creep crack growth� vibration� Corrosion & environment� 3-D investigations

� disc� cycle temperature� limit permanent growth and deformation� fatigue and creep fatigue failure

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2nd Information meeting on High Temperature Engineering -Investigation of High Temperature Reactor Materials (HTR)

HTR-MWP 2 High Temperature Materials� WP 2.2 Turbine (blades & disc)� Identification of the materials with high potential

interest and a compilation of existing data� Selection of promising grades for further R&D� Development and testing of available alloys to meet

HTR requirements� Test work concentrates on turbine disc and blade

materials. Short term tensile / creep tests (air, vacuum)from 850 to 1300 oC, Fatigue tests at 1000 oC at CEA.Creep & creep / fatigue tests in Helium at JRC on aservo hydraulic test rig.

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2nd Information meeting on High Temperature Engineering -Investigation of High Temperature Reactor Materials (HTR)

HTR-M1 High Temperature Materials� Turbine (blades)� Identification & procurement of chosen material� Medium term creep tests up to 850 oC & 10,000 h

– aged and as received material

� Damage analysis & modeling– includes mechanical, creep & tensile testing

� updating of data base

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2nd Information meeting on High Temperature Engineering -Investigation of High Temperature Reactor Materials (HTR)

� Results to date & next steps (turbine blades & disc)� results to date� Review of materials started - initial list identified� identification of formats /properties for data base underway� literature searches in progress� Specification on design use

� next steps� Assembling of material data for selected steels� selection of material candidates for tests� finalise test program & test schedule� tests scheduled to begin mid 2002

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2nd Information meeting on High Temperature Engineering -Investigation of High Temperature Reactor Materials (HTR)

� WP3 Graphite

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2nd Information meeting on High Temperature Engineering -Investigation of High Temperature Reactor Materials (HTR)

Material Issues (Graphite Core)Properties� most important for gas reactors is dimensional change - graphite

initially shrinks then grows (turnaround) - dependent on irradiationtemperature

� when irradiated by fast neutrons the damage to the crystallinestructure causes changes in physical & mechanical properties

� property values vary for different graphites� most of the available data comes from materials test reactors� many graphites used in earlier designs are no longer available� further testing is needed to fill in gaps� way forward is to use past data as pfar as possible plus current

understanding to derive the required information

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2nd Information meeting on High Temperature Engineering -Investigation of High Temperature Reactor Materials (HTR)

Material Issues (Graphite Core)Corrosion

� Main concern is graphite burning under severe air ingress accidents� Improvement of the experimental data base for oxidation models:

– reactivity against oxygen & steam

– diffusion coefficients

� suitability of new C- based materials under accident typicaltemperatures and pressures

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2nd Information meeting on High Temperature Engineering -Investigation of High Temperature Reactor Materials (HTR)

Structural Integrity Issues (Graphite Core)

� dimensional change can affect core geometry and componentintegrity

– disengagement of components & loss of control

– take up of design clearances

– high stresses in graphite leading to cracking

� lifetime validation critically dependent on properties under fastneutron irradiation

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2nd Information meeting on High Temperature Engineering -Investigation of High Temperature Reactor Materials (HTR)

� HTR-M� WP 3 Graphite� State of the art and first version of data base of

properties� Assess requirement for new graphites and needs of

future HTR's� Tests to obtain kinetic data on fuel matrix &

structural graphite in oxygen (823 and 1023 oK)-partial pressures 2 & 20 kPa - using thermo-gravimetric facility THERA at FZJ.

� Testing of oxygen resistance of advanced C-basedmaterials (CFC’s, doped materials, SiC) - steam & airusing oxidation facility INDEX of FZJ

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2nd Information meeting on High Temperature Engineering -Investigation of High Temperature Reactor Materials (HTR)

� HTR-M1� Graphite� Review / confirm key graphites and testing needs for

future HTR’s� Procurement & manufacture of samples in

conjunction with graphite manufacturers� Pre-irradiation of test pieces in HFR and post

irradiation tests in shielded facilities� Assessment including extrapolation to higher doses &

recommendations for future testing� Corrosion work on coated pebbles to identify ways of

improving the bond of the coating before newirradiation tests are undertaken.

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2nd Information meeting on High Temperature Engineering -Investigation of High Temperature Reactor Materials (HTR)

� Graphite - results to date and next steps� results to date� Properties� Review of properties underway� Data base activity started

� Corrosion� Tests completed in air:

– kinetic data in air using THERA

– oxidation resistance of selected CFC’s (non irradiated)

� Thermal conductivity of C-based materials (non-irradiated)

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2nd Information meeting on High Temperature Engineering -Investigation of High Temperature Reactor Materials (HTR)

� Graphite - results to date and next steps (Graphite)next steps� Properties� establish and assemble draft outline of data base� review data omissions

� Corrosion� Tests in steam:

– kinetic data using THERA

– Oxidation resistance of selected CFC’s

– high flow rate experiments (INDEX)

� Thermal conductivity of C-based materials (irradiated)

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2nd Information meeting on High Temperature Engineering -Investigation of High Temperature Reactor Materials (HTR)

� Conclusions� Reliable materials data a key issue in development of HTR

Technology� HTR-M & HTR-M1 projects aim to establish a materials

platform from which to aid future developments� Focus on main component needs� HTR-M & HTR-M1 project and status of work has been

described� Work has started on the materials review and development of a

data base.� Planning for experimental tests has started or is underway (in the

case of graphite corrosion).

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2nd Information meeting on High Temperature Engineering -Investigation of High Temperature Reactor Materials (HTR)

� The work programme described here is co-funded by the European Commission underthe EC/Euratom Framework-5 programme.

� The partners of HTR-M & M1 gratefullyacknowledge the funding provided by theEuropean Commission, and theencouragement and support provided by thestaff of the European Commission DG-Research.