Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
The Materials Test Station: An Accelerator Driven Neutron Source for Fusion Materials Testing Eric Pitcher Presented at: Sixth US-PRC Magnetic Fusion Collaboration Workshop July 10-12, 2012 LA-UR-12-22739 The need for a fusion relevant intense neutron source is well established • 2007 FESAC (Greenwald) Report – Identified a neutron irradiation facility as one of nine initiatives – Recommended assessing the potential for alternative facilities to reduce or possibly eliminate the need for the US to participate as a full partner in the International Fusion Materials Irradiation Facility (IFMIF) • 2009 FES Research Needs Workshop (ReNeW) – Advocated a fusion-relevant neutron source to be an essential mission requirement • 2012 FESAC Opportunities for Fusion Materials Science and Technology Research Now and During the ITER Era – “The lack of an intense fusion relevant neutron source for conducting accelerated experiments is the largest obstacle to achieving a rigorous scientific understanding and developing effective strategies for mitigating neutron-induced material degradation.” The LANL Materials Test Station is a moderate cost option that can largely satisfy this mission need. Sixth US-PRC Magnetic Fusion Collaboration Workshop, San Diego, July 10-12, 2012 Slide 2 Materials Test Station Mission: Irradiate nuclear fuels and materials in a fast neutron spectrum • The DOE Office of Nuclear Energy (DOE-NE) has funded the conceptual design of the Materials Test Station (MTS) as a fast spectrum nuclear fuels and materials test bed • Once completed, the MTS will be the only fast neutron spectrum irradiation capability outside of Russia and Asia • The MTS can provide the US with a fast spectrum test capability in 4 years for about $85M • The MTS neutron irradiation environment is also suitable for fusion materials testing Sixth US-PRC Magnetic Fusion Collaboration Workshop, San Diego, July 10-12, 2012 Slide 3 MTS will be built at the Los Alamos Neutron Science Center (LANSCE), a multidisciplinary National User Facility • Lujan Neutron Scattering Center – – – • Weapons Neutron Research Facility – – • nuclear physics Isotope Production Facility – • dynamic imaging Ultra-Cold Neutron Source – • Nuclear cross sections semiconductor testing Proton Radiography – • Materials science Biology Nuclear cross sections medical & research isotopes Materials Test Station (under design) – fuels and materials testing Sixth US-PRC Magnetic Fusion Collaboration Workshop, San Diego, July 10-12, 2012 Slide 4 The MTS will be driven by a 1-MW proton beam delivered by the LANSCE accelerator • MTS will be built in an existing experimental hall • Use of existing materials and infrastructure greatly reduces capital costs compared to a green field Sixth US-PRC Magnetic Fusion Collaboration Workshop, San Diego, July 10-12, 2012 Slide 5 MTS neutron flux and energy spectrum is similar to a fast reactor, with an added high-energy tail NEUTRON ENERGY SPECTRUM SPATIAL DISTRIBUTION OF THE FAST NEUTRON FLUX Peak Fast Flux (1015 n/cm2/s) Facility MTS (USA) 1.3 BOR-60 (Russia) 2.8 CEFR (China) 2.5 MTS flux level will be half of the world’s most intense research fast reactors. Sixth US-PRC Magnetic Fusion Collaboration Workshop, San Diego, July 10-12, 2012 Slide 6 Figures of merit for fusion materials testing • Irradiation temperature – 300˚C to 1000˚C range, controllable to ±10˚C • He/dpa ratio – “Fusion relevant” range is 10 – 15 appm He/dpa • Damage rate – Desirable to reach a total dose exceeding 100 dpa in a few years • Irradiation volume – Sufficient to simultaneously irradiate hundreds of test specimens • Nuclear recoil spectrum similar to fusion reactor 1st wall • Similar evolution in elemental composition with dose With the exception of damage rate, the MTS substantially satisfies these figures of merit. Sixth US-PRC Magnetic Fusion Collaboration Workshop, San Diego, July 10-12, 2012 Slide 7 MTS produces a broad range of He/dpa ratios fuels irradiation region materials irradiation region “fusion relevant” He/dpa ratio from 10 to 15 appm/dpa • Peak dpa rate is 32 dpa/fpy or 17 dpa/year (50% LANSCE availability) • There is an irradiation volume of about 100 cm3 where samples will receive 7 dpa/year or more with fusion-relevant He/dpa ratios Sixth US-PRC Magnetic Fusion Collaboration Workshop, San Diego, July 10-12, 2012 Slide 8 Different facilities exhibit distinct features in their neutron and nuclear recoil energy spectra 104 7E+14 fusion reactor 1st wall (DEMO) 6E+14 IFMIF 5E+14 fast reactor d / dT (b/MeV) neutron lethargy flux (n.cm –2 .s–1) 102 4E+14 3E+14 100 2E+14 fusion reactor 1st wall IFMIF 1E+14 0 10-3 MTS fast reactor 10-2 10-4 MTS -2 10 -1 10 0 10 1 10 neutron energy (MeV) 2 10 3 10 10-6 10-5 10-4 10-3 10-2 10-1 100 nuclear recoil energy, T (MeV) Low-energy portion of the neutron and nuclear recoil spectra are similar for fusion reactor, fast reactor, and MTS. Sixth US-PRC Magnetic Fusion Collaboration Workshop, San Diego, July 10-12, 2012 Slide 9 101 The damage production function W(T) of a fusion reactor 1st wall and MTS match in the critical region below 50 keV 1.0 0.8 Isolated defects with higher rate of survivability MTS fast reactor W(T) 0.6 fusion reactor 1st wall 0.4 IFMIF 0.2 Sub-cascade production 0.0 10-3 10-2 10-1 nuclear recoil energy, T (MeV) 100 Sixth US-PRC Magnetic Fusion Collaboration Workshop, San Diego, July 10-12, 2012 101 Slide 10 Major elemental composition evolution in MTS is similar to that for a fusion reactor first wall reflector proton beam mask proton beam spallation target fuel samples backstop materials samples spallation target materials samples materials region tally volumes reflector EUROFER97 irradiated to 200 dpa Sixth US-PRC Magnetic Fusion Collaboration Workshop, San Diego, July 10-12, 2012 Slide 11 Summary • The irradiation environment in MTS is appropriate for fusion materials testing of steel alloys with respect to: – – – – irradiation temperature He/dpa ratio nuclear recoil spectrum change in elemental composition with dose • Peak damage rate for iron alloys is 17 dpa/calendar year • Irradiation volume is sufficient for the simultaneous irradiation of hundreds of miniature test specimens • Conceptual design completed last year, awaiting DOE approval • MTS provides the US a cost effective alternative to joining the ITER Broader Approach Sixth US-PRC Magnetic Fusion Collaboration Workshop, San Diego, July 10-12, 2012 Slide 12