NSUF 18-1603: APT Characterization of RPV Steels from the UCSB ATR-2 Neutron Irradiation Experiment

We propose to use APT to characterize of a set of key RPV alloys to build on a growing Small Angle X-Ray Scattering (SAXS), SANS, X-ray Diffraction (XRD), Scanning/Transmission Electron Microscopy (S/TEM) and APT database. The steels were irradiated to a fluence of 1.2 to 1.4x1020 n/cm2 at Tirr 250°C and 290°C in the UCSB ATR-2 experiment. This work will continue to fill remaining gaps in composition and irradiation conditions not yet characterized. The wide range of compositions covered in these steels will improve the understanding of the synergistic relationships among the various solutes and assist in the development of advanced alloys for future light water reactors. The unique combination of characterization tools (SANS, SAXS, XRD, S/TEM, APT) will provide vital insights into MNSPs including: volume fraction, size, number density, composition, crystal structure and magnetic character. This microstructural data will be quantitatively linked to changes in mechanical properties (Dsy) measured by tensile, shear punch and hardness testing. The resulting combined databases, including the very large international surveillance database, will be used to develop advanced embrittlement models for low-flux, high-fluence vessel irradiation conditions. SAXS, SANS data from steels irradiated at 290°C at the same flux and fluence to isolate the role of Tirr. Overall, this project should be seen as programmatic sponsored work aimed at supporting the LWRSP RPV task. The primary experimental objectives of this proposal include: 1) Measure volume fraction, size, number densities and precipitate compositions of MNSPs formed under irradiation at high fluence 1.4x1020 n/cm2 to fill in condition/composition gaps, including at Tirr 250°C. 2) Examine and quantify segregation of Ni/Mn/Si/P to microstructural features such as grain boundaries, dislocations and dislocation loops. These experimental objectives will be achieved within 6 months of the date of the award. The expected period to finish all FIB sample preparation is within one week. APT at CAES will be scheduled directly following this time period as APT needle samples become available. Data analysis will be performed over the next several months by PI.

추가 정보

필드	값
Abstract	We propose to use APT to characterize of a set of key RPV alloys to build on a growing Small Angle X-Ray Scattering (SAXS), SANS, X-ray Diffraction (XRD), Scanning/Transmission Electron Microscopy (S/TEM) and APT database. The steels were irradiated to a fluence of 1.2 to 1.4x1020 n/cm2 at Tirr 250°C and 290°C in the UCSB ATR-2 experiment. This work will continue to fill remaining gaps in composition and irradiation conditions not yet characterized. The wide range of compositions covered in these steels will improve the understanding of the synergistic relationships among the various solutes and assist in the development of advanced alloys for future light water reactors. The unique combination of characterization tools (SANS, SAXS, XRD, S/TEM, APT) will provide vital insights into MNSPs including: volume fraction, size, number density, composition, crystal structure and magnetic character. This microstructural data will be quantitatively linked to changes in mechanical properties (Dsy) measured by tensile, shear punch and hardness testing. The resulting combined databases, including the very large international surveillance database, will be used to develop advanced embrittlement models for low-flux, high-fluence vessel irradiation conditions. SAXS, SANS data from steels irradiated at 290°C at the same flux and fluence to isolate the role of Tirr. Overall, this project should be seen as programmatic sponsored work aimed at supporting the LWRSP RPV task. The primary experimental objectives of this proposal include: 1) Measure volume fraction, size, number densities and precipitate compositions of MNSPs formed under irradiation at high fluence 1.4x1020 n/cm2 to fill in condition/composition gaps, including at Tirr 250°C. 2) Examine and quantify segregation of Ni/Mn/Si/P to microstructural features such as grain boundaries, dislocations and dislocation loops. These experimental objectives will be achieved within 6 months of the date of the award. The expected period to finish all FIB sample preparation is within one week. APT at CAES will be scheduled directly following this time period as APT needle samples become available. Data analysis will be performed over the next several months by PI.
Award Announced Date	2018-09-17T12:09:46.18
Awarded Institution	Center for Advanced Energy Studies
Facility	Microscopy and Characterization Suite
Facility Tech Lead	Yaqiao Wu
Irradiation Facility	None
PI	Takuya Yamamoto
PI Email	[email protected]
Project Type	RTE
RTE Number	1603