Annexes to SEC(2011)929 - Document d'accompagnement au rapport sur l'acctivite du reacteur a haut flux durant l'annee 2009 - Main contents
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This page contains a limited version of this dossier in the EU Monitor.
| dossier | SEC(2011)929 - Document d'accompagnement au rapport sur l'acctivite du reacteur a haut flux durant l'annee 2009. |
|---|---|
| document | SEC(2011)929  |
| date | July 18, 2011 |
In 2009, NRG has also continued to perform structural analyses by powder diffraction using the diffractometer of beam tube HB3a. Among others, materials for electricity storage applications have been investigated upon request of Leiden University. On the same instrument, a powder diffraction spectrum of lithium hydride, a candidate material for hydrogen storage, was measured on behalf of the JRC Cleaner Energies Unit
3.2. CRYO Experiment: Alpha-Emitters Radiotoxicity Reduction
Research conducted to date tends to suggest that the decay half-life of alpha-emitting isotopes embedded in a metallic matrix may be reduced at cryogenic temperatures. If confirmed, this may ultimately contribute to the reduction of nuclear waste.
To avoid any possible speculations, JRC is trying to verify the status/outcome of these studies by conducting an experiment in the HFR, called CRYO. The CRYO irradiation will produce 210Po, which is a pure alpha emitter, embedded in a metallic matrix of copper. This will be achieved by the irradiation of eight copper – bismuth disks and transmutation of 209Bi.
Irradiation of the CRYO experiment started on 22 December 2009, for a duration of one HFR cycle (~29 full power days).
4. Fuel Irradiations in the HFR 4.1. HELIOS Fuel Experiment: Americium Transmutation
Americium is one of the radioactive elements that contribute to a large part of the radiotoxicity of spent fuels. Transmutation, by irradiation in nuclear reactors of long-lived nuclides such as 241Am, is therefore an option for the mass and radiotoxicity reduction of nuclear wastes. The Helios experiment, as part of the FP6 EUROTRANS Integrated Project on Partitioning and Transmutation, deals with irradiation of U-free fuels containing americium. The main objective of the HELIOS irradiation is to study in-pile behaviour of U-free fuel targets, such as CerCer (Pu, Am, Zr)O2 and Am2Zr2O7+MgO or CerMet (Pu, Am)O2 +Mo, in order to gain knowledge on the role of microstructure and temperature on gas release and on fuel swelling. During the irradiation, a significant amount of helium is produced by the transmutation of americium. The gas release study is of vital importance to allow better performance of the U-free fuels. Two different approaches are followed to reach early helium release:
1. Provide release pathways by creating open porosities, i.e. release paths to the plenum gas. Therefore, in the HELIOS test matrix a composite target with a MgO matrix containing a network of open porosity has been included.
2. Increase target temperature to promote the release of helium from the matrix. Americium or americium/plutonium zirconia based solid solutions along with CerMet targets have been included in the test matrix to study the effects of the temperature. Adding plutonium allows for fission, which will increase the target temperature at the beginning of irradiation (BOI).
Irradiation of the HELIOS experiment started on 29 April 2009 and lasted about 250 full power days, i.e. until the HFR stop, on 19 February 2010.
The start-up of the experiment has been flawless. During the first cycle, the experiment has showed a higher neutron flux than expected. Investigations are being conducted and will be finalised with the measurement of the fluence detectors installed near to each test pin. This higher flux does not jeopardise the results of the experiment. As a matter of fact, it might even help as the experiment will receive more neutron fluence than expected. This will counteract the premature stop by raising the burn-up and helium production.
4.2. MARIOS Fuel Irradiation: Minor Actinide Recycling
The MARIOS irradiation programme, as part of FAIRFUELS, is a series of irradiations dealing with heterogeneous recycling of Minor Actinides (MAs) in Sodium-cooled Fast Reactors (i.e. the MA-bearing-blanket concept). MAs, such as americium and curium, are not always recycled and remain key elements composing the waste. The aim of the MARIOS irradiation is to investigate the behaviour of MA targets in a uranium oxide matrix carrier. For the first time, americium (241Am) is included in a (natural) uranium oxide matrix Am0.15U0.85O1.94. This irradiation will produce large amounts of helium within the targets. Its goal is therefore to study the fuel behaviour in terms of helium production and swelling. These may cause significant damage to the material under irradiation. The MARIOS irradiation will start in autumn 2010 and will last for approximately 300 full power days.
During 2009, the preliminary design of MARIOS was finalised. The nuclear analyses have been concluded and the fission power generated by the fuel pellets has been calculated. The fuel pellets, made by CEA in France, are in preparation and will arrive in Petten during spring 2010.
4.3. SPHERE Fuel Irradiation: Safer Fuels
Within the FP7 FAIRFUELS project, the irradiation SPHERE has been planned for 2011. SPHERE has been designed to compare conventional pellet-type fuels with so-called sphere-pac fuels. The latter have the advantage of an easier, dust-free fabrication process. When dealing with highly radioactive minor actinides, dust-free fabrication processes are especially essential to reduce the risk of contamination.
To assess the irradiation performance of Sphere-Pac fuels compared to conventional pellet fuel, a dedicated SPHERE irradiation experiment will be performed. For this purpose, americium-containing fuel, both pellet and sphere-pac types, will be fabricated at JRC-ITU in Germany. These fuels will be irradiated in the HFR. This irradiation is the first of its kind, as no minor actinide bearing Sphere-Pac fuel has ever been irradiated before. The SPHERE irradiation will last for approximately 300 full power days.
The preliminary design for the SPHERE irradiation experiment has started and the first fabrication trials have started.
4.4. HTR Fuel Pebble Irradiation HFR-EU1
After a pause of several years, after the end of the German fuel qualification programme, JRC-IE resumed in 2004 new HTR fuel irradiations in the HFR, this time with a focus on determining the limits of old and newly produced fuel in terms of temperature and burn-up for possible use in advanced pebble bed HTRs with very high coolant outlet temperature (up to 1000°C) and improved sustainability. A first experiment with 5 German AVR fuel pebbles (HFR-EU1bis) was completed in 2005 and followed by a second (HFR-EU1) to be completed in early 2010 which investigates higher burn-up tolerance of existing German pebbles and of newly produced Chinese fuel.
In the HFR-EU1 experiment, the irradiation targets are 5 pebbles irradiated in 2 separately controlled capsules. Two of the pebbles were of recent Chinese production (INET), the other three of former German production (AVR). Both fuel types were tested to higher burn-up but at lower temperature than in HFR-EU1bis. Contrary to HFR-EU1bis, in this test, the fuel surface temperatures were kept constant at 900°C (INET) and 950°C (AVR). These conditions are more benign for the fuel, because increasing burn-up causes decreasing central fuel temperature with time. The initially targeted burn-up was 17% FIMA (INET) and 20% FIMA (AVR) which is significantly higher than the licence limit of the HTR-Modul (approx. 8% FIMA). In the course of the experiment, this objective had however to be reduced due to excessive irradiation time requirements and technological difficulties, notably with premature thermocouple drop-outs. In early 2008, massive thermocouple failure in the capsule containing AVR pebbles had put the experiment on hold for 1.5 years.
The above failure meant that a new safety case had to be made and to implement and qualify new safety instrumentation including up-to-date HPGe gamma spectrometry for fission gas release analysis. This new installation allowed permanent fission gas release monitoring of the capsules. So far, the measured release over birth values (R/B) remained consistently low in both capsules, thus hinting at the absence of particle failure even at the already achieved high burn-ups.
The irradiation could eventually be resumed at the end of 2009 with a foreseen end of irradiation in February 2010, just before the planned HFR outage.
After termination of the experiment, the irradiation capsule will be dismantled and transported to JRC-ITU (Karlsruhe) for further PIE and safety testing.
5. Fuel and Reactor Structural Materials 5.1. PYCASSO experiments: for Tighter HTR Fuels
Within the Raphael (V)HTR 6th Framework EU-programme, the PYCASSO experiments have been devised to investigate coating behaviour under irradiation. Samples have been included from CEA (France), JAEA (Japan) and KAERI (Republic of Korea), which makes this irradiation a real Generation IV effort.
PYCASSO-I has been removed after a very successful irradiation in April 2009. The complex dismantling started in autumn of the same year.
During the autumn of 2009, the PYCASSO-II experiment has been introduced into the HFR reactor core. Based on the already excellent performance of PYCASSO-I, some improvements have been introduced, which has resulted in an even more uniform temperature distribution in the different sections in the experiment. As in PYCASSO-I, the PYCASSO-II irradiation targets temperature regions of 900, 1000 and 1100°C, and contains 76 separate particle sample holders. For the CEA particles a larger fluence difference has been envisaged, which has been achieved by moving one CEA section lower in the experiment, and thus at a lower flux level in the HFR core. This section is intended to receive a fluence similar to the maximum fluence in PYCASSO-I, for reference, whilst the other sections will receive a higher fluence by increasing the irradiation duration.
The irradiation has been somewhat delayed by the HFR repair, and will continue with 2 or 3 more cycles after the repair, hence ending at the end of 2010.
5.2. Particle size assessment in ODS Steels using Small Angle Neutron Scattering
Oxide Dispersion Strengthened (ODS) Steels are among the candidate materials for use in future generation nuclear power systems. The structural and fuel cladding materials in GEN IV systems are confronted with more aggressive environments than in current light water reactors. This concerns thermal loading, corrosive behaviour of the primary coolant, neutron dose or their synergetic effect. Small Angle Neutron Scattering (SANS) is a method for analysing material inhomogeneities in the 1-1000 Å scale. The scattering data furnishes information concerning size and size distributions of inhomogenities within materials. It can therefore be used to study effects of thermal and/or irradiation ageing in ODS, duplex or Cr rich ferritic steels.
In 2009, the SANS facility at the HFR has been used to collect scattering data from coarse grained ODS steels of grades MA6000, MA956, MA957 and PM2000. The analysis suggests an average size of embedded oxide nanoparticles of around 28 nm. The calculated mean particle size is in good agreement with observations made on this material by Transmission Electron Microscopy (TEM) and Scanning Electron Microscopy (SEM).
5.3. HTR Core Structures: Graphite Irradiations
Graphite is a suitable material to be used as a neutron moderator and reflector in nuclear reactors. Due to its excellent high temperature performance, graphite is used as a structural material in the HTR design (High Temperature Reactor). The European Commission is supporting research projects (RAPHAEL-IP) for the development of HTR technology with the aim to create the technological requirements for designing and constructing an HTR in Europe. To achieve this, new nuclear graphite grades need to be developed and qualified, as the previously used grades are not available anymore. The properties of graphite are changing significantly and non-linearly under neutron irradiation. Therefore the graphite properties need to be obtained at different neutron dose levels. The property curves at two irradiation temperatures, 750ºC and 950ºC, are produced in four irradiation experiments conducted by NRG at the HFR. A crucial part of the programme is the possibility to reload irradiated (and therefore radioactive) graphite samples in new experiments to be able to measure the properties at different dose levels. This requires being able to build the experiments in a shielded environment, i.e. a hot-cell.
In 2009, the experiments INNOGRAPH 1b and INNOGRAPH 2b, loaded with irradiated material from the previous experiments, have been further irradiated. The experiment at 950ºC started in 2008, with samples previously irradiated up to 7 dpa (displacements per atom). An extra dose of 6 dpa is targeted, leading to a cumulative dose in these samples of 13 dpa, to be achieved early 2010.
The experiment at 750ºC, which started in 2007, is still in the HFR. This experiment will be completed by early 2010, after achieving an even higher dose of 23 dpa.
5.4. BLACKSTONE Irradiations: Investigation of AGR Lifetime Extension
The UK has a fleet of Advanced Gas Cooled Reactors (AGRs) operated by British Energy. In order to extend the lifetime of the AGRs, graphite data at high dose and weight loss are required. These data allow the prediction and assessment of the behaviour of AGR graphite cores beyond their currently estimated lifetimes. Graphite degradation is indeed considered to be one of the key issues that will determine the remaining life of the AGRs. The BLACKSTONE irradiations use samples trepanned from AGR core graphite and subject them to accelerated degradation in the HFR. The results are designed to enable the future condition of the AGR graphite to be predicted with confidence.
The BLACKSTONE irradiations started in the first cycle after the HFR stop due to the BPL problem. The BLACKSTONE capsules will continue into 2010 to achieve an irradiation dose of approx. 7 dpa.
6. Fusion Reactor Technology
The HFR irradiation capabilities are used for screening and qualifying fusion materials, components and technology. The HFR contributes to fusion technology development by simulating ITER and DEMO conditions in terms of irradiation temperature and neutron load. Furthermore, the hot cell laboratories perform post-irradiation testing, subsequently providing experimental results on neutron irradiated materials. The main areas of interest are the ITER vacuum vessel, the development of high heat flux components and blanket structures, and the development of the reduced activation materials such as 9Cr steels and innovative materials such as fibre reinforced composites. In addition, irradiation behaviour of ITER diagnostic instrumentation and the in-vessel parts of heating systems, which require dedicated assessment and testing programmes, are of great interest. As part of the qualification of materials supporting the licensing of a future reactor, the design of the International Fusion Materials Irradiation Facility (IFMIF) is under development. The HFR provides ample opportunity to qualify specific materials for the IFMIF target section, instrumentation and mock-ups. Presentations on ITER and DEMO development and qualification activities and the role of HFR in these activities have been delivered at the regular Fusion Symposia and Conferences.
6.1. ITER Vessel/In-vessel
In one of the European design concepts, the design of ITER first wall panels features PH13-8Mo steel as candidate material. After an irradiation campaign, the final report on the Post Irradiation Examination (PIE) of PH13-8Mo has been completed. This report is comprised of the results of the irradiation response up to 2 dpa in terms of yield stress hardening, elastic fatigue resistance and fatigue crack propagation.
Furthermore, a new test facility, called POSITIFE, for the irradiation of ITER primary wall modules is under construction. This facility will allow close simulations of thermal fatigue and simultaneous neutron loading in the HFR Pool Side Facility (PSF). The manufacturing of the components for this irradiation experiment started in 2009. The irradiation will start soon after the repair of the HFR in 2010.
NRG also developed with the Netherlands Organization for Applied Scientific Research (TNO) alternative manufacturing routes for thick tungsten claddings on copper-base substrates. Explosive forming of thick stainless steel sections was demonstrated by Exploform BV, in a joint effort with NRG and TNO to provide alternative manufacturing solutions for the ITER vacuum vessel. The experimental part of both projects on the cladding and the vessel were finished in 2008. Both final reports are now completed. The irradiation response of ODS-Eurofer97 steel at low and medium doses has been investigated by performing irradiation in the SUMO-11 and SUMO-12 experiments. The PIE of the ODS Eurofer97 has been completed in 2009. The final report is expected in 2010.
6.2. HIDOBE Experiments: Beryllium for Fusion
The two objectives of the HIDOBE (HIgh DOse BEryllium irradiation) project are (i) to quantify the long-term behaviour (in terms of swelling, creep and tritium retention for fusion applications) of beryllium under irradiation conditions and (ii) to validate models for the thermo-mechanical behaviour of beryllium under irradiation conditions and tritium kinetics in beryllium. Various grades of beryllium (in pebble and pellet form) and titanium beryllides are irradiated in the HFR for 2 and 4-year periods, in two separate experimental setups (HIDOBE-01 and 02). In the framework of the IEA agreement on Radiation Damage Effects in Fusion Materials, partners in the EU, Japan and the Russian Federation provided these different grades of beryllium specimens. The experiment contained a few piggy-backs of ceramic breeder pebbles, complementary to the shielded HICU case.
Irradiation of HIDOBE-01 has been completed in 2008, with achieving its target dose of 3,000 appm helium. The dismantling has been successfully carried out in 2009 and up to 85% of the samples have been recovered without problems. Preparations for an extensive PIE campaign have been finished in 2009 and PIE will begin in 2010.
The HIDOBE-02 irradiation will continue in 2010, after repair of the BPL, to accumulate a total dose of 6000 appm helium production in beryllium and is expected to finish irradiation in the second quarter of 2011. EXTREMAT: Materials for Extreme Environment (Fission & Fusion)
6.3. EXTREMAT : Materials for extreme environment (Fission and Fusion)
Within various subprojects of the ExtreMat Integrated Project, a large number of materials were developed for use in extreme environments. Their stability under neutron load is investigated by irradiations in the HFR. To this aim, two irradiation capsules have been designed: A high neutron dose capsule (equivalent neutron dose in stainless steel of 5 dpa) in which specimens are irradiated at temperatures of 600°C and 900°C and a low neutron dose capsule, designed to reach a neutron dose of 0.7 dpa, at temperatures of 300°C and 550°C.
Irradiation of both capsules started in 2008 and finished in 2009. Afterwards, the low dose capsule was dismantled and the PIE started and will continue into 2010. The PIE includes measurements of physical properties such as thermal conductivity, thermal expansion and dynamic Young’s modulus and mechanical properties such as tensile and flexural strength.
6.4. ADS Material Development
An experimental Accelerator Driven System (ADS) for the transmutation of Actinides is under development in Europe. It features Liquid Lead Bismuth Eutectic (LBE) as reactor coolant. Lead Bismuth has a low melting point (135 ˚C), but has corrosive properties to structural materials and welds. In addition, transmutation of Bi to the high radiotoxic 210Po is a safety issue in the design of the ADS. Materials R&D is needed to test the corrosion behaviour of T91, 316L and weld specimens during irradiation in contact with LBE, and to examine the deposition of 210Po in the irradiation containers and on the specimens after irradiation.
The irradiation of the two capsules was completed after the first three cycles of 2009. Due to the HFR core loading, the IBIS experiment was moved from position G7 to H6 for the last cycle. Also there, the target temperatures of 300 and 500oC were achieved. IBIS has been irradiated in the HFR for 250 Full Power Days in total, to an irradiation dose ranging from 1 (lower temperature) to 2 dpa (high temperature capsule).
During 2009, the facility for specimen retrieval was commissioned and built in the Hot Cell Laboratory. The Fuel Cell line of the HCL was selected because of the presence of alpha emitting radionuclide 210Po. To assess the risk on handling 210Po, a HAZOP study was performed, which formed the basis of the workplan for the retrieval of specimens. The procedure on the retrieval was performed on a container loaded with specimens and LBE that was not irradiated. Almost no wetting of the LBE on the specimens was observed. A dedicated tensile machine was also installed in this cell to test the irradiated specimens. The tensile specimens have showed no effects of the cyclic heating to 300oC in LBE on the elongation and the ultimate tensile strength.
7. Isotope Production
The year 2009 was again a year of high contrast. It started with the HFR being first out of operation, then operated only when justified by medical necessity and finally operated during the second half of 2009 at absolute maximum medical isotope production capacity.
The HFR entered into operation in mid-February 2009, when it was allowed to operate, only upon request, for medical isotopes production. This was imposed by the lack of alternative supply options in Europe and elsewhere in the world. This process required that each operating cycle was individually justified and approved by the Dutch Government, leading to a series of discontinuous cycles of different operational length. These variations in operation reflect the non-availability of other reactors in the European supply network. Over this period, the HFR ran at relatively high medical isotope production levels, to palliate limited alternative supply options.
In mid-May 2009, the NRU Reactor in Canada (a medical isotope producer) unexpectedly went out of operation due to the identification of a heavy water leak. It remained out of operation for the rest of 2009, triggering a continuous worldwide medical isotope shortage. The response of NRG was to reconfigure the production facilities and operating priorities of the HFR to allow the absolute maximum production levels of key medical isotopes (in particular the production of Molybdenum-99 for Tc-99m Generators). These changes were successfully implemented within 2 weeks after the notification of the NRU problem and Mo-99 production capacity was increased to a level around 180% of normal production. The reconfiguration allowed as many as 11 Mo-99 production irradiations to be performed in parallel. It was estimated that during this period the HFR produced enough material to allow more than 50,000 patient scans per day to be performed worldwide. This represented around 60% of the normal total world demand.
The extreme focus on medical isotope production was extended to all other medical isotopes which were produced in large quantities. This had unfortunately negative effects upon industrial isotope production and in particular on the newly developed business of the irradiation of Silicon Ingots to produce Neutron Transmutation Doped (NTP) Silicon for use in high voltage and other specialist electronic applications. Production of NTP Silicon was suspended until further notice, but it is anticipated that irradiations for this market will be reintroduced during the course of 2010.
During the year, NRG worked closely with other reactors in the medical isotope supply network, the Radiopharmaceutical Companies, the Medical Community, Governmental Departments and international organizations such as the OECD/NEA and the IAEA. These actions aimed at maximizing coordination and cooperation and as a result minimizing the effects of shortages whenever possible. Once again, the year 2009 fully underlined the critical role performed by the HFR and the supporting infrastructure within NRG to ensure the worldwide continuous and smooth supply of isotopes for essential medical services.
8. Financial contributions for the execution of the programme.
In 2009, the following financial contributions were received from Member States for the execution of the programme:
- Belgium: 400,000 €
- France: 300,000 €
- The Netherlands: 8,223,000 €
It should be noted that these contributions cover the expenses according to Annex II to Council Decision 2009/410/Euratom. These amounts have been calculated in order to balance the forecasted costs of the reactor on the period 2009 taking into account an expected level of commercial incomes. In no case does the Commission cover any operational deficit, including potential costs for maintenance or repair.
From this amount the Commission received 800,000 € as provisions for the Decommissioning fund[1]
Other expenditures incurred by JRC and paid from the supplementary programme budget:
- Direct Personnel (e.g. for HFR Supplementary program Management): 276,000 €
- Support HFR (e.g. Legal Advice): 24,000 €
- Utilities (e.g., electricity, water, heating): 783,000 €
- Spent Fuel Management: 1,741,000 €
Due to an unplanned investigation and inspection period in the beginning of the year (period 1/1/2009 to11/2/2009 – see Table 1), the net result for NRG for the operation of the HFR in 2009 was a deficit of 1,090,000 €.
Glossary and Acronyms
ADS Accelerator Driven Systems
appm atomic parts per million
CEA Commissariat à l’Energie Atomique
COVRA Centrale Organisatie Voor Radioactief Afval
DEMO Demonstration Fusion Reactor
DG Directorate General
dpa displacements per atom
EC European Commission
ECN Energieonderzoek Centrum Nederland
EU European Union
EUROTRANS European Transmutation
FAIRFUELS Fabrication, Irradiation and Reprocessing of FUELS and target for transmutation
FIMA Fission per Initial Metal Atoms
FP or FWP Framework programme
GIF Generation IV International Forum
HABOG Interim storage centre for high level waste
HAZOP Hazard and Operability
HB Horizontal Beam Tube
HCL Hot Cell Laboratories
HELIOS Helium in Oxide Structure
HEU High Enriched Uranium
HFR High Flux Reactor
HICU High-fluence Irradiation of breeder Ceramics
HIDOBE High Dose Beryllium Irradiation Rig
HTR High Temperature Reactor
IAEA International Atomic Energy Agency
IE JRC Institute for Energy, Petten (NL)
IEA International Energy Agency
ITER International Thermonuclear Experimental Reactor
JAEA Japan Atomic Energy Agent
JRC Joint Research Centre
KAERI Korea Atomic Energy Research Institute
KFD Kernfysische Dienst
LBE Lead Bismuth Eutectic
LEU Low Enriched Uranium
MARIOS Minor Actinides in Sodium-cooled Fast Reactors
NET Network on Neutron Techniques Standardisation for Structural Integrity
NRG Nuclear Research and consultancy Group
PBA Pebble Bed Assemblies
PBMR Pebble Bed Modular Reactor
POSITIFE Project Pool Side facility Thermally Induced Fatigue
PYCASSO PYcarbon irradiation Creep and Swelling/Shrinking of Objects
PSF Pool Side Facility
R&D Research and Development
RAPHAEL Reactor for Process Heat and Electricity
RTD Research and Technological Development
SANS Small Angle Neutron Scattering
SUMO In-Sodium Steel Mixed Specimens Irradiation
TG Task Group
TN Technology Network
TNO Nederlandse Organisatie voor Toegepast Natuurwetenschappelijk Onderzoek (Netherlands Organization for Applied Scientific Research)
[1] The yearly contribution to the decommissioning fund has passed from 400,000 €/year to 800,000 €/year since 2004 due to a re-evaluation of decommissioning costs. This amount is taken from both the regular budget of the supplementary programme and by the gained interest on the bank account of the supplementary programme (the amount of the interest over 2009 was € 374K and therefore, €426K was added from the regular supplementary programme budget of 2009).