J. C. Kuijper, A.I. van Heek, J.B.M. de Haas (NRG)R. Conrad, M. Burghartz (JRC-IE)J.L. Kloosterman (IRI/TU Delft)

OECD NEA NSC MeetingSecond Information Exchange Meeting on Survey of Basic Studies in the

Field of High Temperature Engineering10-12 October 2001, Paris

Present Status in the Netherlands ofResearch Relevant to

High Temperature Gas-Cooled ReactorDesign

Introduction

• Update on HTR-related HFR irradiation experiments since1st IEM (1999)

• Extension to auxiliary experiments, model calculations andsoftware development, auxiliary studies

• Overview/highlights only!• Organisations:

– JRC-IE (previously JRC-IAM)– NRG (merger of nuclear units of KEMA Arnhem and ECN Petten)– IRI, Delft University of Technology– others...

Outline

• Introduction• Characteristics of HFR Petten• HFR irradiation experiments and (calculational) support

– Irradiations of HTR fuel– Irradiations of HTR structural materials (graphite/RPV steel)

• Auxiliary experiments• Model calculations and software development• Auxiliary studies

Characteristics of HFR Petten

• Multipurpose materials testing reactor• Light-water cooled & moderated, tank-in-vessel type• 45 MW nominal power• 19 in-vessel core positions for material testing• Pool side facility for out-of-vessel testing• Utilization for fission, waste and fusion related R&D• Radioisotope production and medical application as BNCT• Neutron-radiography, activation analysis• 12 beam tubes

HFR Programme

• HFR belonging to the JRC-IE of the EC• Four years Supplementary Programme, 2000 - 2003, supported by

European Council decision of 6.12.1999• Since 1996, HFR managed and operated by joint and single

organizational structure between JRC-IE and NRG, the HFR Unit• Aim: market oriented approach and concentration of long-

standing competences in exploiting nuclear facilities

HFR irradiation experimentsand (calculational) support (1)

•Annual programme:–11 cycles per year–~ 25 full power days per cycle–annual availability more than 270 full power days–outstanding record since initial start in 1961

•Operating strategy:–operation at preset and reproducible conditions–preset time schedule–regular update of plant–new reactor vessel in operation since 1985

HFR irradiation experimentsand (calculational) support (2)

• Infrastructure and on-site services:– Computational studies provided by NRG (neutronics,

thermal hydraulics, mechanics); pre-irradiation andfollow-up

– Design of irradiation facilities by JRC-IE and NRG– Fabrication and quality control by ECN (ISO 9001)– NDE (neutron radiography) and X-ray available at

JRC-IE and NRG– PIE at NRG hot cell labs– Waste disposal by NRG

HFR irradiation experimentsand (calculational) support (3)

• Past experiences with HTR fuel and graphite irradiationexperiments: see paper and IEM1

• Present activities in HTR fuel irradiation experiments:– HFR-EU1 (irradiation of fuel pebbles; EU 5FP “HTR-F”)– HFR-EU2 (irradiation of GA fuel compacts)

• Present activities regarding irradiation of HTR structuralmaterials:– RPV material irradiation in LYRA facility (EU 5FP “HTR-M”)– Graphite irradiation planned for 2001-2005 (EU 5FP “HTR-M1”)

HFR-EU1 test-EU1 test

• HFR-EU1 is the first irradiation within the HTR-F projectunder the umbrella of HTR-TN

• Three spherical fuel elements with LEU reference coatedparticle fuel, type GLE-4

• Irradiation starts in 2002• Extreme high burn-up test up to 20 % FIMA within 2 years• Fuel has been designed for 8.9 % FIMA, but was qualified up

to 15 % in capsule tests and up to 20 % in AVR mass testwithout irradiation induced failure of particle coatings

HFR-EU1HFR-EU1

Irradiation parameters

• Required and maximum allowable parameters– Temperature:

• 800°C at surface of FE, average of poles & equator• 1100°C is the max. allowable central temperature (theoretical

value)– Fission power:

• Max. allowable power is 2400 W, considering 9600 CPs per FE– Burn-up:

• Required is 200 GWd/tHM for the highest loaded• The lowest loaded fuel element will receive ~170 GWd/tHM

– Fast neutron fluence:• The max. allowable fast fluence is: 8 x 1025 m-2 (E >0.1 MeV)

Design of FacilityDesign of Facility

• Design of in-pile facility:– Sample holder with 2 independent capsules in REFA-172 thimble– Fuel elements are doubly contained– Instrumentation consists of thermocouples, dosimeters and purge gas

lines– Fuel elements are hold in place by graphite half-shells– Capsules are purged with high-purity He for surveillance of fission gas

release– Adjustable gas mixture in REFA containment serves for temperature

control– Option for vertical displacement of sample holder to optimize fluence

profile– Option to use built-in fission gas filters in case of high release of fission

gases– Options to tailor neutron spectrum

Design scheme HFR-EU1 rigSpherical 60 mm FE

Auxiliary experiments

• HTR-PROTEUS reactivity effects (IRI)– several reactivity measurement methodes (pulsed neutron source,

inverse kinetics, noise analysis)– analysis by Monte Carlo and deterministic codes

• HTTR start-up core physics (NRG, IRI)– IAEA CRP “Evaluation of HTGR Performance”– calculational benchmark: intercomparison of

SCALE/KENO/BOLD-VENTURE (IRI) andWIMS/PANTHERMIX (NRG)

– calculations in agreement with reactivity measurements• Long-term behaviour of disposed spent HTR fuel (NRG)

– EU 5FP “HTR-N” and “HTR-N1” Work Package 5– leaching experiments on SiC and fuel kernels (both unirradiated

and irradiated)

Model calculations and software development

• South African PBMR: typical pebble bed nuclear powerplant for utilities:– Core physics (NRG)– Shielding (NRG)– CFD analysis of primary pipe rupture (NRG)

• ACACIA (INCOGEN): small (40 MWth) combined heatand power unit:– Safety analysis– Fission product transport

• Other:– Pu-incineration in HTR (EU 5FP “HTR-N” and “HTR-N1”) (NRG,

IRI)– HTR with burnable poison (IRI, NRG)– HTR system dynamics (IRI, NRG)

PBMR core phyics (NRG) (1)

• Extension of the PANTHERMIX code system (3-Dneutronics; 2-D R-Z HTR thermal hydraulics) for themodelling of pebble bed reactors with continuous fuelcirculation

• Investigation of equilibrium condition• Investigation of burn-in scenario• To attain real equilibrium at least 10 passes required

PBMR core physics (2)

HTR with burnable poison (IRI, NRG) (1)

• Fundamental study on cell level by IRI• Aim: minimize reactivity swing as function of the

irradiation time• NRG recently started an investigation on the use of

burnable poison in a “cartridge core” ACACIA

Computational model

Burnable ParticleFuel zone

(The radius of the fuel zone determines the effective number of fuelparticles per burnable particles in a pebble)

Macro cell

Micro cell

The k∞∞∞∞ as a function of the irradiation time for the reference case withoutBP and for spherical "hollow" burnable particles with different radii.

0.9

0.95

1

1.05

1.1

1.15

1.2

1.25

1.3

0 200 400 600 800 1000 1200EFPD

Kinfinitive

Reference

Hollow BP R=0.46mm - Vfuel / V BP = 10300

Hollow BP R=0.3mm - Vfuel / V BP = 10300

The k∞∞∞∞ as a function of the irradiation time for the reference casewithout BP and for spherical burnable particles with different radii.

0.9

0.95

1

1.05

1.1

1.15

1.2

1.25

1.3

0 200 400 600 800 1000 1200 1400 1600EFPD

Kinfinite

R=0.3 mm - Vfuel / VBP = 7 500R=0.46 mm - Vfuel / VBP = 7 500

Reference

Auxiliary studies

• Since beginning of the 90’s organisations in the Netherlandsare involved in auxiliary studies concerning HTR design

• INCOGEN programme (Innovative Nuclear COGENeration):– plant layout– ECS design– control philosophy– inspection and maintenance– licensing– economics and market potential

• Present activities include:– RPV materials database (JRC-IE with CEA)– Gas Cooled Fast Reactor (NRG)– Revised cost assessment for ACACIA direct nuclear cogeneration plant

(NRG)

Summary

• JRC’s HFR Petten still very important: numerous testirradiations of fuels and other materials relevant to HTRdesign

• Since beginning of 90’s growing involvement andexpertise of Dutch organisations in other HTR-relatedinvestigations

• International framework