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Title: Void formation and helium effects in 9Cr-1MoVNb and 12Cr-1MoVW steels irradiated in HFIR and FFTF at 400/degree/C

Abstract

Martensitic/ferritic 9Cr-1MoVNb and 12Cr-1MoVW steels doped with up to 2 wt% Ni have up to 450 appm He after HFIR irradiation to /approximately/38 dpa, but only 5 appm He after 47 dpa in FFTF. No fine He bubbles and few or no larger voids were observable in any of these steels after FFTF irradiation at 407/degree/C. By contrast, many voids were found in the undoped steels (30-90 appm He) irradiated in HFIR at 400/degree/C, while voids plus many more fine He bubbles were found in the Ni-doped steels (400-450 appm He). Irradiation in both reactors at /approximately/400/degree/C produced significant changes in the as-tempered lath/subgrain boundary, dislocation, and precipitation structures that were sensitive to alloy composition, including doping with Ni. However, for each specific alloy the irradiation-produced changes were exactly the same comparing samples irradiated in FFTF and HFIR, particularly the Ni-doped steels. Therefore, the increased void formation appears solely due to the increased helium generation found in HFIR. While the levels of void swelling are relatively low after 37-39 dpa in HFIR (0.1-0.4%), details of the microstructural evolution suggest that void nucleation is still progressing, and swelling could increase with dose. The effect of helium on void swelling remains amore » valid concern for fusion application that requires higher dose experiments. 15 refs., 14 figs., 8 tabs.« less

Authors:
;
Publication Date:
Research Org.:
Oak Ridge National Lab., TN (USA)
OSTI Identifier:
6567246
Report Number(s):
CONF-880613-26
ON: DE89004798
DOE Contract Number:  
AC05-84OR21400
Resource Type:
Conference
Resource Relation:
Conference: 14. international symposium on effects of radiation on materials, Andover, MA, United States, 27 Jun 1988; Other Information: Portions of this document are illegible in microfiche products
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; 36 MATERIALS SCIENCE; FERRITIC STEELS; PHYSICAL RADIATION EFFECTS; MARTENSITE; DAMAGING NEUTRON FLUENCE; DOPED MATERIALS; FFTF REACTOR; FIRST WALL; HELIUM EMBRITTLEMENT; HFR REACTOR; SWELLING; THERMONUCLEAR REACTOR MATERIALS; VOIDS; ALLOYS; CARBON ADDITIONS; EMBRITTLEMENT; ENRICHED URANIUM REACTORS; EPITHERMAL REACTORS; FAST REACTORS; IRON ALLOYS; IRON BASE ALLOYS; IRRADIATION REACTORS; LIQUID METAL COOLED REACTORS; MATERIALS; MATERIALS TESTING REACTORS; NEUTRON FLUENCE; RADIATION EFFECTS; REACTORS; RESEARCH AND TEST REACTORS; RESEARCH REACTORS; SODIUM COOLED REACTORS; STEELS; TANK TYPE REACTORS; TEST REACTORS; THERMAL REACTORS; THERMONUCLEAR REACTOR WALLS; WATER COOLED REACTORS; WATER MODERATED REACTORS; 700209* - Fusion Power Plant Technology- Component Development & Materials Testing; 360106 - Metals & Alloys- Radiation Effects

Citation Formats

Maziasz, P J, and Klueh, R L. Void formation and helium effects in 9Cr-1MoVNb and 12Cr-1MoVW steels irradiated in HFIR and FFTF at 400/degree/C. United States: N. p., 1988. Web.
Maziasz, P J, & Klueh, R L. Void formation and helium effects in 9Cr-1MoVNb and 12Cr-1MoVW steels irradiated in HFIR and FFTF at 400/degree/C. United States.
Maziasz, P J, and Klueh, R L. Fri . "Void formation and helium effects in 9Cr-1MoVNb and 12Cr-1MoVW steels irradiated in HFIR and FFTF at 400/degree/C". United States. https://www.osti.gov/servlets/purl/6567246.
@article{osti_6567246,
title = {Void formation and helium effects in 9Cr-1MoVNb and 12Cr-1MoVW steels irradiated in HFIR and FFTF at 400/degree/C},
author = {Maziasz, P J and Klueh, R L},
abstractNote = {Martensitic/ferritic 9Cr-1MoVNb and 12Cr-1MoVW steels doped with up to 2 wt% Ni have up to 450 appm He after HFIR irradiation to /approximately/38 dpa, but only 5 appm He after 47 dpa in FFTF. No fine He bubbles and few or no larger voids were observable in any of these steels after FFTF irradiation at 407/degree/C. By contrast, many voids were found in the undoped steels (30-90 appm He) irradiated in HFIR at 400/degree/C, while voids plus many more fine He bubbles were found in the Ni-doped steels (400-450 appm He). Irradiation in both reactors at /approximately/400/degree/C produced significant changes in the as-tempered lath/subgrain boundary, dislocation, and precipitation structures that were sensitive to alloy composition, including doping with Ni. However, for each specific alloy the irradiation-produced changes were exactly the same comparing samples irradiated in FFTF and HFIR, particularly the Ni-doped steels. Therefore, the increased void formation appears solely due to the increased helium generation found in HFIR. While the levels of void swelling are relatively low after 37-39 dpa in HFIR (0.1-0.4%), details of the microstructural evolution suggest that void nucleation is still progressing, and swelling could increase with dose. The effect of helium on void swelling remains a valid concern for fusion application that requires higher dose experiments. 15 refs., 14 figs., 8 tabs.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {1988},
month = {1}
}

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