Comparison of nuclear irradiation parameters of fusion breeder materials in high flux fission test reactors and a fusion power demonstration reactor (original) (raw)
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Fusion Engineering and Design, 2011
Present pathway to fusion reactors includes a rigorous material testing program. To reach this objective, irradiation facilities must produce the displacement damage per atom (dpa), primary knock-on atom (PKA) spectrum and gaseous elements by transmutation reactions (He, H) as closely as possible to the ones expected in the future fusion reactors (as DEMO).The irradiation parameters (PKA spectra and damage function) of some candidate materials for fusion reactors (Al 2 O 3 , SiC and Fe) have been studied and then, the suitability of some proposed experimental facilities, such as IFMIF and TechnoFusion, to perform relevant tests with these materials has been assessed.The following method has been applied: neutron fluxes present in different irradiation modules of IFMIF have been calculated by the neutron transport McDeLicious code. In parallel, the energy differential cross sections of PKA have been calculated by using the NJOY code. After that, the damage generated by the PKA spectra was analyzed using the MARLOWE code (binary collision approximation) and custom analysis codes. Finally, to analyze the ions effects in different irradiation conditions in the TechnoFusion irradiation area, the SRIM and Marlowe codes have been used. The results have been compared with the expected ones for a DEMO HCLL reactor.
Fusion materials irradiations at MaRIE'S fission fusion facility
Fusion Engineering and Design, 2011
Los Alamos National Laboratory's proposed signature facility, MaRIE, will provide scientists and engineers with new capabilities for modeling, synthesizing, examining, and testing materials of the future that will enhance the USA's energy security and national security. In the area of fusion power, the development of new structural alloys with better tolerance to the harsh radiation environments expected in fusion reactors will lead to improved safety and lower operating costs. The Fission and Fusion Materials Facility (F 3), one of three pillars of the proposed MaRIE facility, will offer researchers unprecedented access to a neutron radiation environment so that the effects of radiation damage on materials can be measured in situ, during irradiation. The calculated radiation damage conditions within the F 3 match, in many respects, that of a fusion reactor first wall, making it well suited for testing fusion materials. Here we report in particular on two important characteristics of the radiation environment with relevancy to radiation damage: the primary knock-on atom spectrum and the impact of the pulse structure of the proton beam on temporal characteristics of the atomic displacement rate. With respect to both of these, analyses show that F 3 has conditions that are consistent with those of a steady-state fusion reactor first wall.
The Suitability of the Materials Test Station for Fusion Materials Irradiations
Fusion Science and Technology, 2012
Los Alamos National Laboratory has completed the conceptual design of the Materials Test Station (MTS), an accelerator-driven neutron source for irradiating nuclear fuel and materials in a fast neutron spectrum. In many respects, the irradiation conditions in the MTS are quite similar to those experienced by the first wall of a fusion reactor. Calculated He-to-dpa (displacements per atom) ratios range from 35 down to 5 appm He/dpa, allowing for critical testing of helium effects on mechanical properties under fusion-relevant conditions. We present here a brief history on the assessment of spallation sources for fusion materials testing and discuss irradiation conditions in the MTS as they pertain to testing materials for fusion reactor applications. In particular , we examine the production of spallation residues in the MTS for the fusion reactor candidate alloy EUROFER97 and compare the concentrations of these transmutation elements to those predicted for a fusion reactor first wall. We show that predicted yields of phosphorous and sulfur in steel alloys irradiated to high dose in fusion-relevant regions of the MTS are below typical as-fabricated concentrations.
Modelling of materials under irradiation in inertial fusion reactors: Damage, tritium and activation
Neutron intensities and energy spectra in structural support materials versus time after target emission are presented for two IFE protections (LiPb, Flibe); these data are strongly required for evaluation of pulse effect. A multiscale modelling (MM) study of pulse irradiation in metals (Fe) has been extended up to the microscopic scale; we explain physics effects and remark differences with continuous irradiation. Static and dynamic validation of a new tight-binding molecular dynamics code to accurately determine defects energetic in SiC is presented. The effect of HT is remarked together with that of HTO when studying tritium releases; it is shown that HT contributes 90-98% to the total dose from ingestion of natural agriculture and meat and the rest comes from inhalation by the re-emission to the atmosphere. A Monte Carlo procedure estimates the effect of activation cross section uncertainties in the accuracy of inventory calculations and final materials consequences, which is based on simultaneous random sampling of all the cross sections and it is implemented in the activation code ACAB. The procedure is applied in collaboration with LLNL to the analysis at the National Ignition Facility gunite chamber shielding under a reference pulsing operation. Preliminary results show that the 95 percentile of the distribution of the relative error of the contact dose rate can take values up to 1.2. Model is also promising when applied to the uncertainty analysis of activation in IFE power plants, by using a continuous-pulsed model to represent the IFE real pulsed irradiation.
Radiation damage studies on the first wall of a HYLIFE-II type fusion breeder
Energy Conversion and Management, 2005
The radiation damage on the first wall [made of (1) a ferritic steel (9Cr-2WVTa), (2) a vanadium alloy (V-4Cr-4Ti) and (3) SiC f /SiC composite] of an inertial fusion energy (IFE) reactor of HYLIFE-II type is investigated. A protective liquid wall with variable thickness, containing Flibe + heavy metal salt (UF 4 or ThF 4) is used for first wall protection. The content of heavy metal salt is chosen as 4 and 12 mol%. Neutron transport calculations are performed with the aid of the SCALE4.3 System by solving the Boltzmann transport equation with the XSDRNPM code in 238 energy groups and S 8-P 3 approximation. A flowing wall with a thickness of 60cmcanextendthelifetimeofthesolidfirstwallstructuretoaplantlifetimeof30yearsfor9Cr−2WVTaandV−4Cr−4Ti,whereastheSiCf/SiCcompositeasfirstwallneedsaflowingwallwithathicknessof60 cm can extend the lifetime of the solid first wall structure to a plant lifetime of 30 years for 9Cr-2WVTa and V-4Cr-4Ti, whereas the SiC f /SiC composite as first wall needs a flowing wall with a thickness of 60cmcanextendthelifetimeofthesolidfirstwallstructuretoaplantlifetimeof30yearsfor9Cr−2WVTaandV−4Cr−4Ti,whereastheSiCf/SiCcompositeasfirstwallneedsaflowingwallwithathicknessof85 cm to maintain the radiation damage limit. Substantial extra revenue can be gained through the insertion of a heavy metal salt constituent into Flibe, which allows breeding fissile fuel for external reactors and increasing energy multiplication
Calculation of damage function of Al2O3 in irradiation facilities for fusion reactor applications
Journal of Nuclear Materials, 2013
A rigorous material testing program is essential for the development of the nuclear fusion world program. In particular, it is very important to predict the generation of the displacement damage in materials, because the irradiation intensity expected in fusion conditions is such that the performance of materials and components under these extreme conditions is unknown. To study the damage produced by neutrons in materials of interest for fusion, a specific computational methodology was developed. Neutron fluxes expected in different irradiation facilities (International Fusion Materials Irradiation Facility [IFMIF] and DEMO-HCLL) and in different irradiation spots were obtained with particles transport codes (McDeLicious, MCNP). The energy differential cross sections of primary knock-on atoms were calculated using the NJOY code. Resulting data were input into the Monte Carlo code MARLOWE to calculate the corresponding displacements (i.e., interstitials (I) and vacancies (V)). However, the number of Frenkel pairs created during irradiation strongly depends on the recombination radius between interstitials and vacancies. This parameter corresponds to the minimum distance below which instantaneous recombination occurs. Mainly, the influence of such parameter on the damage function in Al 2 O 3 was assessed in this report. The displacements per atom values calculated as a function of the recombination radius considered are compared to experimental data to determine the most appropriate capture radius. In addition, the damage function and damage dose generated at different experimental irradiation facilities are compared with those expected in DEMO. The conclusion is that both IFMIF and TechnoFusión (future triple beam ion accelerator to emulate fusion neutron irradiation effects in materials) facilities are suited to perform relevant irradiation experiments for the design of DEMO.
Laser and Particle Beams, 2005
In the field of computational modelling for S&E analysis our main contribution refers to the computational system ACAB [1] that is able to compute the inventory evolution as well as a number of related inventory response functions useful for safety and waste management assessments. The ACAB system has been used by Lawrence Livermore National Laboratory (LLNL) for the activation calculation of the National Ignition Facility (NIF) design [2] as well as for most of the activation calculations, S&E studies of the HYLIFE-II and Sombrero IFE power plants . Pulsed activation regimes can be modeled (key in inertial confinement fusion devices test/experimental facilities and power plants), and uncertainties are computed on activation calculations due to cross section uncertainties. In establishing an updated methodology for IFE safety analysis, we have also introduced time heat transfer and thermalhydraulics calculations to obtain better estimates of radionuclide release fractions. Off-site doses and health effects are dealt with by using MACSS2 and developing an appropriate methodology to generate dose conversion factor (DCF) for a number of significant radionuclides unable to be dealt with the current MACSS2 system. We performed LOCA and LOFA analyses for the HYLIFE-II design. It was demonstrated the inherent radiological safety of HYLIFE-II design relative to the use of Flibe. Assuming typical weather conditions, total off-site doses would result below the 10-mSv limit. The dominant dose comes from the tritium in HTO form. In the Sombrero design, a severe accident consisting of a total LOFA with simultaneous LOVA was analyzed. Key safety issues are the tritium retention in the C/C composite, and the oxidation of graphite with air that should be prevented. The activation products from the Xe gas in the chamber are the most contributing source to the final dose leading to 47 mSv. We also analyzed the radiological consequences and the chemical toxicity effects of accidental releases associated to the use of Hg, Pb, and
Fusion Science and Technology, 2010
A concise overview is given on materials applied in fusion technology. The influence of plasma operation on the behaviour of reactor components and diagnostic systems is discussed with emphasis on effects caused by fast particles reaching the reactor wall. Issues related to primary and induced radioactivity are reviewed: tritium inventory and transmutation. Tritium breeding in the reactor blanket, separation of hydrogen isotopes and safety aspects in handling radioactively contaminated components are also included.