Comprehensive nuclear materials 1 06 the effects of helium in irradiated structural alloys Comprehensive nuclear materials 1 06 the effects of helium in irradiated structural alloys Comprehensive nuclear materials 1 06 the effects of helium in irradiated structural alloys Comprehensive nuclear materials 1 06 the effects of helium in irradiated structural alloys Comprehensive nuclear materials 1 06 the effects of helium in irradiated structural alloys Comprehensive nuclear materials 1 06 the effects of helium in irradiated structural alloys
1.06 The Effects of Helium in Irradiated Structural Alloys Y Dai Paul Scherrer Institut, Villegen PSI, Switzerland G R Odette and T Yamamoto University of California, Santa Barbara, CA, USA ß 2012 Elsevier Ltd All rights reserved 1.06.1 1.06.2 1.06.2.1 1.06.2.2 1.06.2.3 1.06.2.4 1.06.2.5 1.06.2.6 1.06.3 1.06.3.1 1.06.3.2 1.06.3.3 1.06.3.4 1.06.3.5 1.06.3.6 1.06.3.7 1.06.4 1.06.4.1 1.06.4.2 1.06.4.2.1 1.06.4.2.2 1.06.4.3 1.06.4.4 1.06.5 1.06.5.1 1.06.5.2 1.06.5.3 1.06.5.4 1.06.5.5 1.06.6 1.06.6.1 1.06.6.2 1.06.7 References Introduction and Overview Experimental Approaches to Studying He Effects in Structural Alloys Single, Dual, and Triple-Beam CPI Neutron Irradiations with B or Ni Doping In Situ He Implantation Spallation Proton–Neutron Irradiations, SPNI Proposed Future Neutron-Irradiation Facilities Characterization of He and He Bubbles A Review of Helium Effects Models and Experimental Observations Background Historical Motivation for He Effects Research Void Swelling and Microstructural Evolution: Mechanisms The CBM of Void Nucleation and RT Models of Swelling Summary: Implications of the CBM to Understanding He Effects on Swelling and Microstructural Evolution HTHE Critical Bubble Creep Rupture Models Experimental Observations on HTHE Recent Observations on Helium Effects in SPNI Microstructural Changes Mechanical Properties of FMS After SPNI Helium effects on tensile properties and He-induced hardening effects Helium effects on fracture properties and He-induced embrittlement effects Mechanical Properties of AuSS After SPNI Summary of Effects of Irradiation on Tensile and Fracture Properties Atomistic Models of He Behavior in Fe He Energetics and He–Defect Complex Interactions He Interactions with Other Defects Helium Migration Master Models of He Transport, Fate, and Consequences Dislocation–Cavity Interactions Radiation Damage Tolerance, He Management, Integration of Helium Transport and Fate Modeling with Experiment ISHI Studies and Thermal Stability of Nanofeatures in NFA MA957 Master Models of He Transport Fate and Consequences: Integration of Models and Experiment Summary and Some Outstanding Issues Abbreviations ANL appm APT Argon National Laboratory Atomic parts per million Accelerator Production of Tritium AT AuSS bcc BF 142 146 146 147 148 149 149 150 151 151 152 155 156 162 163 166 168 168 172 172 174 177 178 178 179 180 180 182 182 183 183 185 186 189 As tempered Austenitic stainless steels Body-centered cubic Bright field 141 142 CBM CD CPI CT CVN CW DBTT The Effects of Helium in Irradiated Structural Alloys Critical bubble model Cluster dynamics Charged-particle irradiations Compact-tension Charpy V-notch Cold-worked Ductile-to-brittle transition temperature DDBTT Shifts in DBTT DFT Density functional theory dpa Displacement per atom EAM Embedded atom method EELS Electron energy-loss spectroscopy fcc Face-centered cubic FFTF Fast Flux Test Facility FMS Ferritic–martensitic steels FNSF Fusion Nuclear Science Facility FZJ Forschungscentrum Juălich GB Grain boundary HFIR High Flux Isotope Reactor HFR High Flux Reactor (Petten) HTHE High temperature helium embrittlement IFMIF International Fusion Material Irradiation Facility IG Intergranular ISHI In situ He implantation KMC/KLMC Kinetic Monte Carlo–lattice Monte Carlo LANSCE Los Alamos Neutron Science Center LBE Liquid lead-bismuth eutectic LTHE Low temperature hardening-helium embrittlement MD Molecular dynamics MS Molecular statics NF Nanofeatures NFA Nanostructured ferritic alloys ODE Ordinary differential equation OEMS (Positron) orbital electron momentum spectra ORNL Oak Ridge National Laboratory PAS Positron annihilation spectroscopy PIE Postirradiation examination RED Radiation-enhanced diffusion REP Radiation enhanced precipitation RIP Radiation-induced precipitation RIS Radiation-induced segregation RT Rate theory SANS Small-angle neutron scattering SIA Self-interstitial atom SINQ Swiss Spallation Neutron Source SP SPN SPNI STIP TDS TEM TMS V Small punch Spallation proton–neutron Spallation proton–neutron irradiations SINQ Target Irradiation Program Thermal desorption spectroscopy Transmission electron microscopy Tempered martensitic steels Vacancy 1.06.1 Introduction and Overview This chapter reviews the profound effects of He on the bulk microstructures and mechanical properties of alloys used in nuclear fission and fusion energy systems Helium is produced in these service environments by transmutation reactions in amounts ranging from less than one to thousands of atomic parts per million (appm), depending on the neutron spectrum, fluence, and alloy composition Even higher amounts of H are produced by corresponding n,p reactions In the case of direct transmutations, the amount of He and H are simply given by the content weighted sum of the total neutron spectrum averaged energy dependent n,a and n,p cross-sections for all the alloy isotopes (hsn,ai) times the total fluence (ft) The spectral averaged cross-sections for a specified neutron spectrum can be obtained from nuclear database compilations such as SPECTER,1 LAHET,2 and MCNPX3 codes He and H are also produced in copious amounts by very high-energy protons and neutrons in spallation targets of accelerator-based nuclear systems (hereafter referred to as spallation proton–neutron (SPN) irradiations, SPNI).4,5 The D–T fusion first wall spectrum includes 14 MeV neutrons (%20%), along with a lower energy spectrum (%80%) The 14 MeV neutron energy is far above the threshold for n,a (%5 MeV) and n, p (%1 MeV) reactions in Fe.6 Note that some important transmutations also take place by multistep nuclear reactions For example, thermal neutrons (nth) generate large amounts of He in Ni-bearing alloys by a 58Ni(nth,g)59Ni(nth,a) reaction sequence These various irradiation environments also produce a range of solid transmutation products High-energy neutrons also produce radiationinduced displacement damage in the form of vacancy and self-interstitial atom (SIA) defects Vacancies and SIA are the result of a neutron reaction and scatteringinduced spectrum of energetic primary recoiling The Effects of Helium in Irradiated Structural Alloys Table Typical dpa, He, and H production in nuclear fission, fusion, and spallation facilities Irradiation facility Fission reactor Fusion reactor first wall Spallation targets dpa range (in Fe) He per dpa (in Fe) H per dpa (in Fe) Temperature ( C)