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European Facility for innovative reactor and transmutation neutron data

Final Report Summary - EUFRAT (European Facility for innovative reactor and transmutation neutron data)

Executive Summary:
EUFRAT is a Transnational Access programme at the Institute for Reference Materials and Measurements of the Joint Research of the European Commission (EC-JRC-IRMM) with the objective to facilitate the access of outside users to the nuclear data facilities of its Unit Standards for Nuclear Safety, Security and Safeguards. It was the goal to promote a coherent use of the measurement infrastructure in order to meet high-priority nuclear data requests from European nuclear safety authorities, the nuclear research community and industry.

The Sustainable Nuclear Energy Technology Platform foresees in its Deployment Strategy a common European approach to the safety evaluation of innovative reactor systems and the fuel cycle. For feasibility studies and safety assessments, very detailed simulations of reactor behavior in nominal, incidental and accidental conditions are needed. These studies make extensive use of simulation methods in order to predict the running conditions of nuclear energy systems. High-quality nuclear data, in particular complete and accurate information about the nuclear reactions taking place in nuclear systems, are an essential component of such modeling capabilities. Recent investigations on the impact of nuclear data uncertainties on performance characteristics of systems considered for waste transmutation and for GenIV reactors show that the accuracy and completeness of existing nuclear data is an important issue for the safety assessment of present-day and innovative nuclear energy systems.

Project Context and Objectives:
The Deployment Strategy of the Sustainable Nuclear Energy Technology Platform foresees, among others, a common European approach to the safety evaluation of innovative reactor systems and the fuel cycle. For feasibility studies and safety assessments, very detailed simulations of reactor behavior in nominal, incidental and accidental conditions are needed. To predict the nuclear system characteristics with sufficient accuracy a precise simulation of all relevant nuclear reactions is necessary. High-quality nuclear reaction data are an essential component of such modeling capabilities. While simulation calculations are becoming more and more performing with the rapid advances in computer technology, the accuracy of these calculations is largely determined by the accuracy of the nuclear input data. Reducing uncertainties and extending nuclear data sets by dedicated measurements is an important issue for safety assessments of present-day and innovative nuclear energy systems. The EU is faced with the situation that not many European laboratories are able to perform such experiments with the required accuracy. In the EU only the facilities operated by the Institute for Reference Materials and Measurements of the Joint Research of the European Commission (EC-JRC-IRMM) and funded by the EURATOM programme are dedicated entirely to the area of nuclear data for fission energy applications.

The experiments can be subdivided into three areas:
1. Nuclear data for the safety of present-day and innovative reactors and of waste transmutation systems:
- waste transmutation and minimisation, accelerator-driven systems
- improved reactor operation and fuel management
- advanced innovative nuclear energy systems
- nuclear reactor safety

2. Development of experimental set-ups and techniques needed for these data measurements:
- characterisation and calibration of new facilities or set-ups
- validation of innovative measurement methods
- testing and/or calibration of new detector systems
- characterisation of samples

3. Advanced methods in nuclear technologies, safety and security

The final goal of the project was to deliver new, additional or more accurate neutron cross-section data and other fission-related data in nuclear technology domains as fission reactor technology, fission reactor and fuel cycle safety, high burnup fuels, nuclear waste transmutation and innovative reactor systems.

To optimise scientific output and value-for-money of the EUFRAT project:
formed a structure to cover the overall management of the project, which organised all activities, monitored their progress and guided corrective actions.
designed an efficient method for attracting and evaluating research projects of the highest quality and priority.
created the necessary means to promote access to the JRC-IRMM infrastructures.
launched four Calls for proposals.
organised selection of the best experimental proposals based on peer review. The Programme Advisory Committee, composed of international nuclear data experts and stakeholders, assessed all proposals on the basis of criteria as scientific importance, match to the neutron data community demands, quality of nuclear data that can be obtained and importance for the strategic goals of the Euratom Work Programme.
created for each accepted experiment the best facility experimental conditions to guarantee an optimal data output.
guaranteed the optimal execution of the approved experiments at the JRC-IRMM facilities.

For the experiments approved by the PAC the users could make use of the measurement infrastructure of IRMM and they were supported by a local contact person. Different experiments were executed, ranging from high-resolution neutron cross-section measurements at the GELINA time-of-flight facility to activation measurements, fluence measurements, detector calibration, and fission measurements at the Van de Graaff facility. Technology-oriented investigations could also be performed, such as feasibility tests for the planning of long-term investigations, detector calibration or spectrum measurements. After execution of the experiments, the data were analysed at the home institutions of the external users.

105 users participated in the experiments, 62 were supported by EUFRAT, and the other users got financial support from their home institute. The researchers that participated at the experiments were from 34 different isntitutes.

EUFRAT was also successful in attracting scientists that never used the facilities before. 45% were first-time users. This is a remarkable result if takes into account that the nuclear data community in Europe is quite small and that EUFRAT was preceded by another transnational access programme, named NUDAME.

Project Results:
The Institute for Reference Materials and Measurements from the Joint Research Centre from the European Commission (EC-JRC-IRMM) in Geel, Belgium, operates two particle accelerator facilities: a 150 MeV linear electron accelerator (GELINA) with a high-resolution neutron time-of-flight (TOF) facility and a 7 MV light-ion Van de Graaff (VdG) facility used for the production of quasi-monoenergetic neutron fields. This research equipment is unique in Europe. It is specially designed for the measurement of highly accurate neutron cross-section data. Measurements at these facilities provide data which form the basis for a wide range of evaluated neutron cross section data. The domains under study encompass safety of fission reactor and fuel cycle technology, high burnup fuels, nuclear waste transmutation and innovative reactor systems.

The energy domain of interest can be subdivided into two regions:
resolved resonance region: to reveal the complicated cross-section resonance structure the extremely good energy resolution of a dedicated time-of-flight (TOF) facility like GELINA is required. The Geel Electron Linear Accelerator GELINA is a white neutron source, where the time-of-flight (TOF) method is used to determine the energy of the interacting neutrons in the energy range covering 11 decades (1 meV - 20 MeV). Among the pulsed white spectrum neutron sources available in the world, GELINA is the one with the best time resolution.
unresolved resonance region and above: here the measured widths of the resonances are larger than the resonance spacing so that the resonances appear to be overlapping. In the energy domain of overlapping resonances and above, neutron beams, as produced with a Van de Graaff facility (VdG) at IRMM, are used. At the Van de Graaff facility quasi mono-energetic beams of neutrons are produced in the energy range up to 24 MeV.

The EUFRAT project promoted the trans-national access to the EC-JRC-IRMM accelerator facilities in order to endorse the neutron data requirements in the field of the safety of present-day and innovative reactors and of waste transmutation systems. It was the objective to offer within 4 years to new external users a total of 4500 supplementary data-taking hours, for 25 experiments. The 33 experiments can be subdivided into three areas:

Nuclear data for the safety of present-day and innovative reactors and of waste transmutation systems.
These measurements delivered new, additional or more accurate neutron cross-section data and other fission relevant data in nuclear technology domains as fission reactor technology, fission reactor and fuel cycle safety, high burnup fuels, nuclear waste transmutation and advanced innovative reactor systems.
Development of experimental set-ups and techniques needed for these data measurements
Advanced methods in nuclear technologies, safety and security

The main deliverables of the experiments are:
the experimental results,
publications in a peer-reviewed scientific journal and/or a conference presentation
validated data sets that will be transferred to the relevant data banks of the Nuclear Energy Agency of the OECD (NEA/OECD) and the IAEA.

The data processing and analysis is performed by the external users at their home institutes, once the experiments at JRC-IRMM are finished. It is well-known in nuclear data research that because of the complexity of the data analysis process and its interpretation, there is a rather long delay between the measurements and the delivery of the validated data. So, the major part of the final results is expected to be delivered after the end date of the project. Nevertheless, the EUFRAT project was quite successful in producing experimental results and peer-reviewed publications in scientific journals and/or at conferences. Results obtained within EUFRAT have also been used and published in two PhD theses and several Master theses from the Member State institutes participating at the experiments.

1. Nuclear data for the safety of present-day and innovative reactors and of waste transmutation systems

Short description of measurements:
Hafnium can be used in reactor systems to regulate the fission process because of its high absorption cross section in the thermal and epi-thermal region. The interpretation of integral benchmark experiments, in both critical and zero-power reactors, identified the poor quality of the nuclear data files for hafnium in the thermal and epi-thermal region. The natural metal is currently used in some light water reactor (LWR) systems as part of the control rod system. Additionally, there have been studies of the potential use of hafnium-based materials in future reactor design including;
- use of hafnium hydrides (HfHx) in the control rods of fast reactors.
- use of hafnium nitride (HfN) as an inert fuel matrix for waste transmutation.
- use of carbides such as (U,Zr,Hf)C as fuel materials in advanced innovative nuclear energy systems because of their high melting points (greater than 3500K).
During the experiments at GELINA the nuclear scattering radii and scattering cross-sections of the natural hafnium isotopes were determined. Values are presented to the JEFF project with resolved resonance parameters derived from measurements.

Short description of measurements:
The accurate knowledge of neutron-induced reaction cross sections is important for applications in nuclear technology. In the past much emphasis has been put on the measurement and evaluation of nuclear data for the existing generation of nuclear power plants. New applications, like the high burn-up of current fuels, Generation IV reactors, alternative fuel cycles, transmutation of nuclear waste or accelerator driven systems, address other isotopes, energy ranges and reactions for which improved nuclear data are mandatory. The capture cross section of 236U is particularly important for the build-up of higher actinides in nuclear fuel, both in the uranium-based fuel cycle, where 236U is produced by capture on 235U, as in the possible future fuel cycle based on 232Th/233U.

Short description of measurements:
Several thorium-based fuel design options investigated in recent years, have demonstrated the basic feasibility of Th based fuel cycles of current and next generation technology. Activities have focused on examining the 232Th/233U cycle as a replacement for conventional uranium-based fuels in existing reactors, as well as a way to manage the growth of plutonium stockpiles by burning plutonium. Over the years, efforts have been made to improve the quality of basic nuclear data in the thorium cycle. Thermal reactor designs and applications have been the driving force for new data evaluations in the low energy range. Recently, data evaluations in the high-energy region have been accomplished primarily in support of transmutation or incineration applications and GEN IV fast reactor design. Recent sensitivity studies of the impact of the cross section uncertainties on the breeding capability of the thorium cycle have shown that fissile regeneration is dominated by the uncertainty in the ratio (called alpha ratio) between the capture and fission cross section of 233U. The available data for this ratio present a dispersion of 25%.

Description of measurements:
For nuclear applications carbon is known as component of moderators such as graphite, polyethylene or paraffin or as coating of Triso particles in advanced high temperature reactors. 12C is the most abundant carbon isotope. Therefore the very precise measurement of neutron cross sections of 12C represents an important goal. In this experiment the (n,n' gamma) cross sections for 12C are determined using the GAINS spectrometer of IRMM is used. GAINS is a new device specifically developed for the study of (n,xgamma) reactions at the GELINA time-of-flight facility. In this experiment also a feasibility study is made for the determination of (n,xgamma) cross sections with x a light charged particle.

Short description of measurements:
Compared to the situation in conventional (thermal) reactors a new type of reactions appears in fast reactors. In these fast reactors (n,xn) reactions (with x>1) become possible despite their high threshold and they play a non negligible role, since above 10 MeV they have cross sections comparable to fission. They modify the neutron spectrum by converting fast neutrons (En greater than 5 MeV) into slow neutrons (En less than 1 MeV) and they modify the criticality of the core. (n,xn) reactions are not well known from the experimental and theoretical point of view. In this experiment the cross section for 232Th(n,xngamma) reactions is measured at the GELINA neutron time-of-flight facility.

Short description of measurements:
Lead is of interest both for developments in nuclear physics and for applications. In engineering and research lead is found everywhere for shielding against gamma-radiation, also in neutron environments. In advanced reactors liquid lead is proposed as a possible coolant alternative to sodium or gas. In accelerator driven systems lead is part of the proposed spallation target.
In nuclear physics the closed proton shell of lead and in particular the doubly closed shell for 208Pb have led to numerous studies of nuclear structure and nuclear reactions to test and develop nuclear models. The (n,xn) reactions on lead are particularly useful to study the quality of model predictions, since they are a good test of the main ingredients in such calculations: optical model, level density and pre-equilibrium reactions. A particular feature of the lead isotopes are the low (n,2n) and (n,3n) thresholds. For instance (n,3n) channels are open well below 20 MeV neutron energy. The reaction 204Pb(n,3n)202Pb is an example of a reaction that could not be studied before (there are no data in EXFOR!) and that may be possible with the Accelerator Mass Spectrometry (AMS) technique. This experiment is the first experimental measurement of the 204Pb(n,3n)202gPb cross section. It has the goal to demonstrate the ability of the AMS technique for reactions in this mass and energy range.

Short description of measurements:
Neutron-induced reaction cross section data on hafnium isotopes are important for nuclear technologies research and development. Hafnium is considered as a constituent of the control elements and structural materials of nuclear reactors due to its high absorption cross section for thermal neutrons, good mechanical properties and extremely high resistance to corrosion. Hafnium is also an alloying element of the low activation materials that are under development for use in the ITER and DEMO reactors. Activation analyses for the high intensity neutron sources require a full set of cross section data comprising all target nuclides that may be present in the materials to be irradiated and taking into account all reactions that may occur over the whole energy range. Of particular importance for the integrity of structural materials is the hydrogen and helium production originating from (n,p) and (n,alpha) reactions. The experimental database for hafnium available in EXFOR is very scarce and inconsistent. In this experiment short-lived reaction cross section measurements on hafnium are measured. Results are obtained for the (n,nâ??), (n,2n), (n,) and (n,n) activation reactions in hafnium

Short description of measurements:
Recently critical benchmark calculation revealed serious problems for systems which contain structural materials, i.e. the cross section data for these materials found in the nuclear data libraries do not perform well. Concerns about data deficiencies in some existing cross-section evaluations from libraries such as ENDF/B, JEFF or JENDL for nuclear criticality calculations have been a prime motivator for new cross-section measurements. There are many troubles associated with existing nuclear data, such as problems related to improper pulse-height weighting functions, neutron sensitivity backgrounds, poorly characterized samples, poor TOF resolution, and too restricted energy range. Consequently, the evaluated data used for calculation of nuclear applications may not be adequate where effects such as self-shielding, multiple scattering, or Doppler broadening are important. Furthermore, many evaluations for nuclides having small neutron capture cross sections are erroneously large because the neutron sensitivity of the old measurements was underestimated. Although their neutron capture cross sections are small, these nuclides can be important absorbers in many nuclear applications and criticality calculations, where accurate cross-section data are essential.

Short description of measurements:
The neutron cross sections for zirconium isotopes are important for several aspects in traditional and advanced nuclear technologies. Zr is considered the best suitable metal among the cladding materials for the production of nuclear fuel elements for all reactor types. In particular Zr alloy materials are the skeletons of the fuel assemblies and are used to make the sealed tubes enclosing the fuel pellets. Main advantage of Zr is the small neutron capture cross section, in combination with favourable chemical and mechanical properties. With the present research programs on Gen-IV reactors with fast neutron spectra, including Accelerator-driven systems (ADS), there is a growing demand for determination of precise capture cross sections for an energy range that goes from thermal to fast neutron spectra.

Short description of measurements:
It is well known that the knowledge of the (n,xn) reactions are of crucial importance for the design of new Generation IV nuclear reactor which explore new energy domains. Indeed an important energy loss mechanism has to be taken into account in the calculations of the new reactors as they lead to neutron multiplication and production of radioactive species. Moreover the precise determination of the (n,xn) reactions cross sections is a key issue in present day's reactor development studies.

Short description of measurements:
Iron is the most common structural material and is widely used in the nuclear industry in thermal and fast reactors, as well as ADS and fusion devices. Its use in GEN-IV reactors is likely to increase, since the upper temperature limit in zirconium alloys is too limiting for the high-temperature design objectives of the new reactors. The main nuclear data requirements are accurate prediction of neutron attenuation in deep penetration problems, heat deposition and gamma production. To cover accelerator applications shielding applications also require the extension of the energy range in the several ten MeV range. Radiative capture in 58Fe is an important reaction in this respect. There are many discrepancies in the available data. A review of the resonance parameters is needed and the covariances for the other resonance parameters need to be included in the evaluation. This experiment is part of a broader effort to further improve the status of evaluated data for the iron isotopes. The results of the measurements will be used to perform a re-evaluation of the neutron induced total and capture cross section for Fe.

Short description of measurements:
Improved and accurate nuclear data are urgently required for the design of advanced reactor concepts (Gen IV, ADS). This demand holds for minor actinides but also for the main fuel materials. Fast neutron induced reactions are such quantities. Existing data for neutron-induced reactions on U and Th have been measured via detection of the prompt radiation, by the activation technique and by detection of emitted particles. A major difficulty in these experiments is the discrimination against the strong gamma-background (e.g. from the competing fission channel) or unfavourable decay schemes.
Up to now, no measurements have been performed for such reactions applying accelerator mass spectrometry (AMS). At the Vienna Environmental Research Accelerator (VERA) laboratory, measurements for neutron-induced reactions have been performed recently in this mass range by combining activation (by a reactor or van de Graaff accelerator) and subsequent AMS detection. In a previous EUFRAT experiment (PAC 1/9) AMS measurements successfully identified the long-lived radionuclide 202Pb produced with neutron activations via 204Pb(n,3n) at the Van de Graaff accelerators of IRMM. In this experiment natural uranium and thorium samples have been activated with neutrons of energies between 18 and 23 MeV. After the activation, the production of longer-lived nuclides was quantified by AMS at VERA. These (long-lived) radionuclides can be the direct product of a reaction, or the final decay product of a directly produced short-lived nuclide. This method for measuring directly reaction products has the advantages that any radiation hazards are avoided and that the involved systematic uncertainties are in no way correlated with the uncertainties inherent e.g. to the time-of-flight technique or the incomplete knowledge of the decay pattern. In this way, this experiment has provided important and independent information for such key reactions of reactor physics.

Short description of measurements:
The public concerns about nuclear waste from nuclear power plants are related primarily to the long term toxicity of the spent nuclear fuels; in the current once-through fuel cycle, this is dominated by plutonium and other minor actinides. The actinides play a dominant role both in terms of total radioactivity and potential dose to the public. As an alternative solution, in 232Th/233U fuel cycle, much lesser quantity of plutonium and long-lived Minor Actinides (MA: Np, Am and Cm) are formed as compared to the 238U/239Pu fuel cycle, thereby minimizing toxicity and decay heat. Recent sensitivity studies of the impact of the cross section uncertainties on the breeding capability of the thorium cycle have shown that fissile regeneration is dominated by the uncertainty in the ratio (called ratio) between the capture and fission cross section of 233U. The calculated uncertainty for the breeding capability of thorium reactors is about 4%, whereas the breeding potential itself is expected to be of the same order. Therefore, it is not yet possible to ensure that this cycle is self-sufficient in the regeneration of the fissile element. The sensitivity results are relatively independent of the neutron energy. However, the most critical region is the resolved resonances in connection with the epithermal spectrum proposed for some moderated Molten Salt Reactors, typically from 1 eV to 100 eV neutron energy range.

Short description of measurements:
Iron represents an important structural material in all nuclear systems. The accurate knowledge of the cross section of all neutron induced nuclear reactions on all iron isotopes is essential for the design studies of any nuclear facility.
The entry number 34 of the NEA Nuclear Data High Priority Request List lists requests the determination of neutron inelastic cross sections for iron with an accuracy of 2-8% for the energy range 0.5 - 1.35 MeV, while the presently achieved accuracy is of the order of 15%.

Short description of measurements:
A nuclear process of special importance for projects aiming for the transmutation of radioactive waste is the radiative neutron capture, which for actinide nuclei competes to neutron induced fission. Here experiments are hampered for short-lived targets. It is thus of importance to improve the predictive power of calculations and/or parameterizations. For these calculations information is needed on the neutron strength function, the density of nuclear levels reached by the first photon emitted after neutron capture and the photon strength function governing the decay to low-lying final states from the capturing resonances. Here neutron reemission competes, thus reducing the capture cross section. In order to increase the insight in this matter an experiment at GELINA is performed in the neutron cross section resonance region to generate information on photon strength and level density so that it can combined to the results of photon scattering experiments performed at other facilities on the neighboring even-even nuclei.

Short description of measurements:
Neutron scattering has a most significant role in Reactor physics. Mathematically speaking, it is corollary to the fact that the scattering term appears explicitly in the well known Boltzmann transport equation, which is the governing formalism of all nuclear reactor simulations.
Neutron scattering is a unique research and analysis technique for exploring the structure and dynamics of materials. The process of neutron scattering is non-destructive and produces results that cannot be achieved by other techniques. In addition Neutron scattering measurements are also performed to assess the feasibility of superconductivity of different suitable wires. The above applications of neutron scattering are all concerned with the fact that the chemical binding or the solid state effect has a governing impact on the scattering procedure. This approach was assumed also to be of major importance for the interaction with nuclear fuel in particular with 238U.

Short description of measurements:
In the frame of the design of new Generation IV nuclear reactor it is necessary to perform high precision measurements of several cross sections on actinides as indicated by the priorities identified in the analysis of Gen IV (NEA / WPEC-26) and advanced fuel cycles (NUDATRA) and also from the IAEA High Priority Request Lists. In the frame of the FP7-ANDES project, the aim of the proposed investigation is to determine the neutron induced gamma production cross sections resulting from inelastic scattering off 238U with a precision of few percents.

Short description of measurements:
The development of neutron cross section standards has been an evolutionary process extending over many decades. Neutron cross section standards are important because they can eliminate the need for a direct measurement of the neutron fluence. The accuracy of cross section or fluence measurements is limited by the uncertainty in the standard cross section relative to which it is measured. The present NEANDC/INDC Nuclear Standards File includes the cross sections for H(n,n), 6Li(n,t), 10B(n,a), 10B(n,alpha gamma), C(n,n), 197Au(n,alpha), 235U(n,f) and 238U(n,f). For neutron energies above thermal the cross section for 197Au(n,gamma) is the only capture cross sections that is considered as a standard. Although many Maxwellian averaged capture cross sections have been determined relative to this cross section, the cross section is only considered as a standard in the energy range between 0.2 and 2.5 MeV. Recently, an attempt has been made to extend the energy region of this standard cross section to the unresolved region, i.e. from 5 to 200 keV. This evaluation was primarily based on results of measurements at a white neutron source. The resulting cross section is in good agreement with results of cross section measurements performed at IRMM. However, the value near 25 keV is approximately 6% higher compared to the result of a Maxwellian averaged value obtained by another measurement, performed Ratynski and Kappeler. To clarify this inconsistency, this EUFRAT experiment was performed at the VdG of IRMM to repeat the measurements of Ratynski and Kappeler.

Short description of measurements:
Improved and accurate nuclear data are urgently required for the design of advanced reactor concepts. Fast neutron induced capture reactions are such quantities. Existing data for neutron-induced reactions on U and Th have been measured via detection of the prompt radiation, by the activation technique and by detection of emitted particles. A major difficulty in these experiments is the discrimination against the strong gamma-background (e.g. from the competing fission channel) or unfavourable decay-schemes. Up no now, no measurements have been performed for such reactions in the MeV energy range applying accelerator mass spectrometry (AMS). Neutron activation with subsequent AMS measurement represents a technique, where interference from fission is completely excluded.

Short description of measurements:
The safety of presently operating and future generation devices together with changes of the mode of operation relies on accurate calculations of the reactor neutronics. Of particular interest in this type of calculations is the accurate and consistent modelling of neutron producing as well as -absorbing reactions like nuclear fission and neutron capture. Essential input to the model is the distinct knowledge about the shape of the compound nucleus energy landscape around the double-humped fission barrier and the location and depths of the super-deformed (SD) minimum, usually called shape isomer. The existence of these fission isomers is a consequence of the appearance of a second minimum in the potential energy surface of actinide nuclei. The result is a double-humped fission barrier as a function of nuclear deformation. In a recent experiment the fission decay mode of the super-deformed (SD) ground state of 235U has been measured and the half-lives for isomeric fission have been determined. This experiment aims for the search of gamma-rays populating the shape-isomeric ground state via neutron-capture in 234U. These parameters will improve the input database for nuclear reaction cross-section calculations.

Short description of measurements:
This experiment is connected with experiments PAC 1/3 and PAC 3/1, â??Simultaneous measurement of 233U capture and fission cross section in the resonance region at GELINA detector efficiency. PAC 1/3 was a first test, PAC 3/1 concerns the efficiency measurement of the ionisation chamber, while this experiment is the final experiment. For more details see the descriptions of PAC 1/3 and 3/1.

Short description of measurements:
During the last decade the scientific interest in resonance neutron-induced reactions on 239Pu has risen considerably because more precise nuclear data are needed for the modeling of a new generation power plants and transmutation of spent fuel, which contains this long-lived radiotoxic isotope in a relatively large amount. According to the nuclear data High-Priority Request List of the Nuclear Energy Agency, several neutron-induced reactions on 239Pu are amongst those where improved data are needed. The neutron fission cross section of 239Pu measured must be known with a precision of about 1%. In addition the prompt fission neutron multiplicity and its variation in the resonance region is another very important characteristic of the 239Pu(n,f) reaction, because it has a significant impact on the reactivity coefficients of advanced reactors. These requests invoked a series of measurements at LANSCE in Los Alamos National Laboratory.

Short description of measurements:
Improved and accurate nuclear data are urgently required for the design of advanced reactor concepts (Gen IV, ADS) and for fusion devices. This demand holds in particular for long-lived radionuclides produced in a neutron environment. Fast neutron induced reactions are such quantities. The long-lived radionuclide 182Hf (t1/2 = 8.9 Myr) is also of concern as nuclear waste in accelerator-driven systems and for future fusion devices as neutron-induced reactions on W and Hf structure materials lead to continuous production of 182Hf. In particular, tungsten-based alloys are considered as structure and plasma-facing materials.

2. Development of experimental set-ups and techniques needed for these nuclear data measurements

Short description of measurements:
The MicroMegas detector is being currently developed as a transparent flux monitor for neutron beam facilities where nuclear cross section data are measured. In most neutron facilities, flux monitors are based on 10B(n,alpha), 6Li(n,alpha) or 235U(n,f), for which the reaction cross-section is considered a standard. The detection principle of the MicroMegas is based on the detection of the electrons created by ionization of the filled gas by charged particles in a first stage and a high electron multiplication and amplification in a second stage. In order to operate as a neutron detector an appropriate neutron-electron converter must be employed. In the MicroMegas a 10B and a 235U are being used, which are deposited at the entrance window.

Short description of measurements:
To meet the uncertainty levels compiled in the Nuclear Data High Priority Request List (HPRL), intense efforts are being made to improve the quality of neutron-induced total and capture cross-section data. However, the final uncertainties on the quantities deduced from the experimental data not only depend on the measurement and data analysis procedures but to a large extent also on the quality of the targets that are used in these experiments.
Independent of the measurement type, the number of atoms per unit area of the nuclide under investigation is the primary quantity of interest. In addition to this areal density, the target should also be verified for homogeneity and the presence of contaminants and impurities, which have an impact on the response. To determine the quantities of contaminants and impurities, Prompt Gamma Activation Analysis and Neutron Activation Analysis (on a representative target) can be performed. Also the resonance structure present in neutron induced cross-sections can be exploited to characterize targets. The appearance of resonances in neutron-induced reaction cross- sections is the basis of the Neutron Resonance Capture (NRCA) and Transmission (NRTA) Analysis techniques. Since resonances can be observed at neutron energies which are specific for each nuclide, they can be used as fingerprints to identify and quantify elements in materials and objects. Both NRCA and NRTA are fully non- destructive methods, which determine the bulk elemental compositions, do not require any sample preparation and result in a negligible residual activation.

Short description of measurements:
The knowledge of the (n,xn) reactions is of crucial importance for the design of new Generation IV nuclear reactor which explore new energy domains. Indeed important energy loss mechanisms (as inelastic scattering for x=1) have to be taken into account in the calculations of the new reactors. Also reactions with x>1 leading to neutron multiplication and production of radioactive species have to be taken into account. The precise determination of the (n,xn) reactions cross sections is also a key issue in present day's reactor development studies.
The Strasbourg group that is performing this experiment has already studied before (n,xngamma) reactions on actinides at GELINA, in particular on 235U and 232Th nuclei. The studies performed up to now are a first step in the preparation of the measurement of the cross sections of the 233U(n,xngamma) reactions. The measurement results are compared with predictions from the TALYS is world-wide used software for the simulation of nuclear reactions. Many state-of-the-art nuclear models are included to cover all main reaction mechanisms encountered in neutron-induced nuclear reactions. It is a versatile tool to analyse basic microscopic experiments and to generate nuclear data for applications. For the reaction channel with n=1, the comparison of the experimental results from the Strasbourg group with the TALYS code predictions shows a relative good agreement over the considered neutron energy range. While for the other cases as the 235U(n,2 xngamma)234U reaction, a ratio of the order of 2 between the TALYS and the experimental values is observed. The obtained results indicate that an optimization of the parameters of the TALYS code has to be done. For example the branching ratios and the level density should be considered more carefully in the code. This experiment was needed to go further in the investigations. To prepare the measurements on 233U the experimental setup had to be optimized because the 233U sample is 20 times more radioactive than the 235U sample used before.

Short description of measurements:
In a previous experiment carried out at the Geel Van de Graaff facility the capability of Single Crystal Diamond Detector (SCD) in performing fast neutron spectroscopy with high resolution has been demonstrated. The results of that experiment have been published in an international peer-reviewed scientific journal. In this experiment Single Crystal Diamond Detectors are used in an experiment to test their capabilities to characterize the neutron fields produced by the Van de Graaff facility when using different targets. The experiments were carried out in order to compare the neutron spectra produced from targets at the beginning and towards the end of their lifetime, and also thick versus thin targets.

Short description of measurements:
There is a compelling need for nuclear data for new technologies in the production of nuclear energy. Having a well-characterized neutron energy spectrum like a Maxwell-Boltzmann neutron spectrum allows performing integral cross-section measurements using Neutron Activation Analysis, in order to validate evaluated nuclear data (e.g. the capture cross-section in the epithermal energy range). This experiment had the objective to validate a method to obtain a Maxwell-Boltzmann neutron spectrum based on the 7Li(p,n) 7Be reaction by shaping the proton beam by shaping the proton beam energy. The method is based on the idea of shaping the proton beam to a particular distribution able to generate a desired neutron spectrum after impinging onto a neutron production target. The measurements showed that the expected neutron spectrum can be obtained and the quality of the neutron spectrum opens possibilities to perform direct measurements of the Maxwellian-averaged cross sections without any correction or approximation.
3. Advanced methods in nuclear technologies, safety and security

Short description of measurements:
Diamond detectors have a great potential to be used as monitors in fast neutron fields. The interactions of high energy neutrons in diamond (12C) may be described in terms of the (inelastic) cross section. At high energy (5-50 MeV region) the n(z,alpha), n(z,p) n(z,d) and n(z,2alpha) are the most important reactions as they produce charged particles which release energy in the diamond, thereby triggering the production of electron-hole (e-h) pairs with a yield of about 105 e-h pairs/MeV.
Recently diamond detectors have been developed as 14 MeV neutron detectors, and used at the Joint European Torus (JET, UK). Exploratory tests have been performed on the VESUVIO measurement station of the ISIS facility. Inserting a diamond detector in the beam for several hours have shown only small changes in the performance (resolution and efficiency) of the device. A dedicated test for a systematic investigation of the actual capabilities of the detector and the assessment of its reliability as a compact fast neutron monitor is therefore of great importance. To this aim the present experiment addressed the very relevant issue of the knowledge of the response function of a diamond detector.

Short description of measurements:
Diamond detectors could be used as fast neutron spectrometers thanks to their outstanding properties. Diamond detectors have a very fast response, they are almost insensitive to gamma radiation (low Z) and they are radiation hard (energy required to displace an atom 42 eV, displacement damage cross section 43 keV-barns at 14 MeV).

Short description of measurements:
Various detector types have been investigated for fast-neutron detection. Recently, C6D6 detectors have been studied for applications such as nuclear nonproliferation and nuclear safeguards. These detectors are based on C6H6 detectors where hydrogen is replaced with deuterium. C6H6 liquid scintillators are very well known for their sensitivity to both gamma rays and fast neutrons and their excellent pulse-shape discrimination (PSD) properties. C6D6 are also sensitive to both gamma rays and fast neutrons. Elastic cross sections for hydrogen and deuterium as a function of neutron energy are similar at energies above 1 MeV, but the average logarithmic energy decrement for deuterium is approximately 0.73 as opposed to 1 for hydrogen. Therefore, less energy is deposited per scattering on deuterium than on hydrogen. These results in lower light output from C6D6 than from C6H6 per unit of energy deposited. The C6D6 light output, however, is sufficient at neutron energies above 1 MeV which makes C6D6 suitable for fast-neutron detection.

Short description of measurements:
The goal of this experiment was to investigate the degradation of the performance of the Silicon Photomultipliers under white beam neutron irradiation from thermal neutrons up to 1-10MeV. These devices are considered as radiation hard and may find potential application in neutron facilities as compact readouts but a full characterization is needed.

Short description of measurements:
In this experiment various organic liquid and plastic scintillators, including C6H6 and C6D6, with several neutron energies between 1 and 10 MeV. These results were used for unfolding purposes for measured unknown sources such as Cf-252, Am-Be, Pu-Be, etc. In addition, all detectors under investigation were directly compared based on measured results to decide what organic scintillators are the most suitable for fast neutron spectroscopy applications. The measurement provided valuable data that will find applications in the fields that require fast-neutron detection with potential characterization of neutron energies, such as nuclear non-proliferation and safeguards.

Potential Impact:
1. Potential impact (including the socio-economic impact and the wider societal implications of the project so far)

The important role of nuclear data and, accordingly also the potential impact of EUFRAT and its societal implications, can be exemplified by:
the support given to the European Commission, Member States and international organisations in their efforts to develop a common European approach to the safety evaluation of nuclear energy systems.
the contribution to the Strategic Research and Innovation Agenda of the SNETP, endorsed by recent statements of EUROSAFE, a European initiative aimed at promoting the convergence of technical nuclear safety practices in Europe and composed of major European nuclear and radiation protection organizations.
the fact that EUFRAT activities are also well-embedded in the global initiatives of international organisations like the International Atomic Energy Agency (IAEA) and the Nuclear Energy Agency of the Organization for Economic Cooperation and Development (NEA-OECD), both developing nuclear safety standards and stimulating the worldwide share of expertise and dissemination of information.
new safety modelling needs emerging after the recent accident in Fukushima.

1.1. Support to a common European approach to the safety evaluation of nuclear energy systems
The research activities within EUFRAT contributed at satisfying the R&D obligations of the Euratom Treaty and supported the European Commission, Member States and international organisations in their efforts to develop a common European approach to the safety evaluation of present-day and innovative nuclear installations, the fuel cycle and nuclear waste management. An objective evaluation of various innovative systems, selection of the technology and the development path for each option can only be based on a reliable and thorough assessment of all underlying safety aspects.

1.2. Contribution to the Strategic Research and Innovation Agenda of the SNETP
The research activities within EUFRAT contributed to the strategic goals of the Strategic Research and Innovation Agenda of the SNETP. The European Commission (EC) has defined a comprehensive strategy towards a sustainable, competitive and secure energy supply in Europe. To accelerate the development and deployment of cost-effective low carbon technologies, the EC presented a Strategic Energy Technology Plan (SET-Plan, 2007) which acknowledges the role of nuclear energy in the mix for electricity production and emphasises the need of improved sustainability for nuclear energy produced by fission. In the wake of the SET-plan, the European actors in nuclear energy have created the Technological Platform for Sustainable Nuclear Energy (SNETP) which elaborated in 2009 a Strategic Research Agenda (SRA). This SRA outlined priorities that direct research efforts of the EU scientific community for both current and future generations of nuclear reactors. Safety of operation of innovative nuclear energy systems is an essential pre-requisite for the nuclear energy option and any new developments need to maintain and improve the present day high safety standards. In order to guarantee the implementation of the highest nuclear safety aspects the SNETP Deployment Strategy foresees modeling and construction of prototypes and demonstrators.

1.3. Support to global initiatives of international organisations developing world-wide promoted nuclear safety standards
EUFRAT activities are also well-embedded in the global initiatives of international organisations like the International Atomic Energy Agency (IAEA) and the Nuclear Energy Agency of the Organization for Economic Cooperation and Development (NEA-OECD), both developing nuclear safety standards and stimulating the worldwide share of expertise and dissemination of information.

1.4. New safety modeling needs emerging after the recent accident in Fukushima
The recent nuclear accident at Fukushima and the lessons learnt have stressed again the need to assess the safety of these advanced nuclear energy systems under all possible and imaginable working conditions. The Fukushima follow-up stress tests have already raised and will further create new important challenges to the accuracy and validation of the available nuclear data. There is already one trend clearly emerging: nuclear safety assessments will move more and more towards the use of best-estimate codes in order to evaluate the performance and safety limits of the present and future nuclear power plants under extreme external conditions and combinations. These best-estimate simulations will be highly dependent on the accuracy of available nuclear data. New methods will be required for reliable estimation of the best-estimate uncertainty starting from the uncertainty in the basic data. This will require new evaluations, even more accurate measurements and adequate safety assessments. A few, rather difficult measurement problems, tackled within EUFRAT fit into this context.

1.5. Long-term integration of European nuclear data community
The Transnational Access programme EUFRAT has contributed to the long-term integration of the nuclear data community because it assured the role of the JRC-IRMM facilities as a pool of attraction for measurements needed to meet present scientific and industrial nuclear data requests and it supported the integration in the nuclear data community of researchers that do not have adequate facilities. It also guaranteed to the scientific actors in the relevant fields the availability of essential resources for neutron data research in Europe and helped integrating European research efforts in a lasting way by fostering long-term collaborations.

The Transnational Access activities (TAA) in CHANDA will be organised in the same way as the TAA in EUFRAT and ERINDA. The TAA of the new consortium of nuclear data facilities will:
Promote and strengthen a structured network of the major experimental facilities in Europe suitable for high-quality nuclear data measurements.
Build a solid and sustainable partnership between the different experimental facilities and between the facilities and their stakeholders.
Enable easier access for external users to participating facilities by creating a coordinated management of the access programmes and by supporting the research groups financially and scientifically.
Pool financial resources to promote and guarantee the effective and coherent use of the participating facilities for nuclear data.
Increase at different facilities the beam time made available for nuclear data for nuclear energy applications.
Direct the beam-time towards requests of highest priority and scientific value, and in line with the priorities of CHANDA.

Within CHANDA the consortium will also develop a strategic vision for the next 15 years and define an adapted management structure with the goal to:
create a self-sustaining organisation of Transnational Access activities in nuclear data,
foster durable long-term partnerships, lasting far beyond the duration of the project,
endorse a coherent and structured approach of facility upgrading and replacement, exploiting synergies and avoiding duplications.

1.6. Active involvement of young students in the experimental activities
In a period where the nuclear research community is confronted with a declining number of young researchers the EUFRAT project had also the objective to attract young people entering the nuclear data research field and to involve them actively in the experimental activities. EUFRAT offered new nuclear scientists and engineers unique training opportunities so that they could prepare their PhD or Master thesis. 20% of the experimentalists that used the JRC-IRMM facilities within EUFRAT were graduate students or post-graduate students. EUFRAT provided unique training and mobility opportunities to these young visiting researchers and technicians, motivating them to continue this type of research in the future.

2. Main dissemination activities and exploitation of results

The main and obvious channels for the dissemination of the results of the research activities obtained within EUFRAT are:
publications of results in international peer-reviewed scientific journals.
presentation at workshops and conferences.
transfer of data to the relevant data banks of the NEA/OECD or IAEA.

The EUFRAT project also used and will use in the future the following communication channels:
the EUFRAT website, electronic mailing actions and publicity actions to attract experimental proposals of high quality.
representation in relevant bodies of NEA and OECD.
cooperation with other projects.
training activities to disseminate the information generated within the project as fast as possible within the scientific community.
organisation of visits and events, for the promotion of the EUFRAT activities to a wider community.
organisation of a general user meeting at the end of the EUFRAT project.

2.1. EUFRAT website
The EUFRAT web-site is the entrance gate for interested scientists seeking information on the project. The web-site is accessible at two levels:
the public zone, accessible for everybody,
the user zone, only accessible by members of the Nuclear Physics Unit, members of the PAC and users that submitted a proposal. The user zone is used for transparent information exchange between EUFRAT and the users that submitted a proposal. The user zone contains all proposals that have been accepted for support by the PAC and the minutes of the PAC meetings. Password-protected access is limited to the PAC and EUFRAT users because proposals and minutes may contain information that is confidential or should not be disseminated on a large scale.

2.2. Representation in relevant committees of NEA or IAEA
The projects and committees of interest to EUFRAT are:
the NEA Nuclear Science Committee
the Joint Evaluated Fission and Fusion file (JEFF) project,
the Working Party for Evaluation Cooperation (WPEC),
the Nuclear Science Committee (NSC) of the OECD-NEA,
the International Nuclear Data Committee of the IAEA-NDS.

2.3. Cooperation with other relevant FP7 projects
Another channel for the dispersion of knowledge generated within EUFRAT towards the research community and stakeholders is the close interaction with other relevant projects, such as ANDES, ERINDA and CHANDA. To coordinate research activities, stimulate co-operative efforts on nuclear data measurements and prevent fragmentation, there is a close scientific interaction between these projects. EUFRAT has also been represented at the General Assemblies of the Sustainable Nuclear Energy technology platform SNETP (Bruxelles, Belgium and Warsaw, Poland).

2.4. Training of young students
In a period where the nuclear research community is confronted with a declining number of young researchers we seek actively contact with young students from universities and schools.
- Involvement in the EUFRAT experiments of young students preparing their PhD or Master thesis was one of the Performance Indicators of the project. 20% of the experimentalists that used the JRC-IRMM facilities within EUFRAT were graduate students or post-graduate students.
- During the duration of the EUFRAT project we had in the SN3S unit of IRMM, six long-term trainees performing work related with EUFRAT and typically spending 6 to 12 months at IRMM.
- We have set-up a suitable training laboratory for nuclear engineering students in order to offer them hands-on experience. During training sessions, students can participate directly to research activities on neutron data measurements together with IRMM researchers. In this framework we had several initiatives.
- Each two years, we organise at JRC-IRMM, with the support from IAEA, NEA and CEA, a one-week course of the Neutron Resonance Analysis School, aimed at PhD students, post-docs and researchers working in the field related to neutron time-of-flight measurements and neutron resonance analysis. The objective is to offer future professionals and researchers a solid background in the different disciplines of nuclear engineering. Each course attracted about 40 participants.
- JRC-IRMM also organised other dedicated training sessions for selected students. During these training sessions, students could participate directly to research activities on neutron data measurements together with IRMM researchers. For example, IRMM organized several advanced courses for nuclear engineering students on 'Accelerators and time-of-flight techniques' within the framework of the 'European Master of Science in Nuclear Engineering' of the Belgian Nuclear Higher Education Network (BNEN). BNEN is embedded in the European ENEN association. Training sessions are also given to nuclear students in other European programmes (e.g. PAN, SPERANSA, SARA, JUAS).

2.5. Organisation of visits and events, communication to the grand public.
JRC-IRMM has also different channels to disseminate knowledge generated within the EUFRAT project to the public at large:
- IRMM is part of the Joint Research Centre of the EC. This implies that there are regular high-level visits of European decision-makers and scientists of all sorts of disciplines. Guided tours of the GELINA and VdG facilities are a standard item during these visits. These guided tours are the ideal occasions to describe the general context of our work and to present the EUFRAT project. Among others, the following high-level visits have been organised during this reporting period:
European Commissioner Ma¡ire Geoghegan-Quinn.
European Commission's Chief Scientific Adviser Anne Glover.
JRC Board of Governors.
delegation of Central Research Institute of Electric Power Industry (CRIEPI), Japan
delegation of Atomic Energy Agency of Israel.
-delegation of the Belgian Scientific and Technical Information Service (STIS)
- We are regularly asked by universities to organise guided tours for interested students.
65 students of EUROSCHOOL on Exotic Beams (Leuven, Belgium)
27 students of European School (Mol, Belgium)
55 Master in Physics students (University of Leuven, Belgium)
12 Master in Nuclear Technology students (XIOS Hasselt, Belgium)
27 Master in Physics students (University of Delft, The Netherlands)
- The JRC-IRMM opens each two years the institute for the wider public in the framework of the 'Open business factories weekends' organised in Belgium. Visitors make a guided tour of the GELINA and Van de Graaff facilities. They get a thorough explanation, adapted to the grand public, of current nuclear issues and their public impact. These events are very successful. At each Open Day more than 500 visitors visited the IRMM nuclear data facilities.
- JRC-IRMM has a long standing experience in publicising research activities and recent achievements with the aim to acquaint citizens with them. The IRMM Director's office deals with relation with media and public, through press release, press conferences and informative reports. They organise also occasional appointments with journalists from televisions and newspapers.

2.6. Organisation of final user meeting
At the end of the EUFRAT project a general user meeting was organized. The user meeting had the objective to bring together representatives of all experimental groups that were supported by the project in order to have a rapid spread of knowledge under directly-involved colleagues, to stimulate exchange of ideas, to discuss open issues and to foster future collaborations. There were 43 subscribed participants.

List of Websites:
Website address: http://irmm.jrc.ec.europa.eu/eufrat
Project type (funding instrument): CSA-SA
Project start date: 01/11/2008
Duration: 48 months
Total budget: EUR 502,908.00
EC contribution: EUR 502,908.00
Coordinator (name, organisation, address, telephone, fax, email):
Mr. Willy MONDELAERS
Unit Head
European Commission
Joint Research Centre
Institute for Reference Materials and Measurements
Unit Standards for Nuclear Safety, Security and Safeguards
Retieseweg 111
B-2440 Geel
Email: willy.mondelaers@ec.europa.eu