Enhanced surveillance program annual report FY98. Dynamic behavior of Pu and U (intermediate strain rates) -- LA12
The Kolsky-Hopkinson Bar Dynamic Test Facility in Building PF-4 at TA-55 recently became operational and the first series of plutonium samples from a baseline alloy were successfully tested on December 8, 1997 through the dedicated efforts of a large number of people in groups NMT-9, NMT-11, MST-8, NMT-5, and JCI. The Enhanced Surveillance Program provided the necessary support for this achievement. The Kolsky-Hopkinson bar is an instrument designed to measure the uniaxial compression stress-strain characteristics of special nuclear materials (SNM) in a glovebox environment at intermediate strain rates (typically 500 s{sup {minus}1} to 10,000 s{sup {minus}1}), over a wide temperature range (cryogenic up to near-melting temperatures), and up to strains of about 50% per test. Due to radiation contamination hazards, SNM samples are contained within a specially designed glovebox with only a small portion of the bar system. The uniaxial high-strain-rate deformation behavior of SNM materials is revealed by stress-strain-strain rate curves calculated from strain signals acquired by gauges on the pressure bars. The compressive stress-strain mechanical behavior of a range of weapons-relevant SNM materials (both baseline and stockpile-aged plutonium and enriched uranium), measured over a wide range of strain rates and temperatures, is necessary to support the development of predictive constitutive models and allows assessment of the mechanical response of SNM as a function of age, processing, and composition. Accurate constitutive material models are essential for simulating the high-rate deformation response of weapon materials. Most FY98 milestones and deliverables were successfully met or were partially completed on schedule. In the case of enriched uranium, testing began six months ahead of schedule. Upgrading the testing temperature capability took six months more than originally planned as a result of the highly formalized and rigorous design change plan (DCP) requirements at TA-55. Specimen availability continues to be a bottle-neck due to over-subscribed plutonium fabrication resources.
- Research Organization:
- Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- W-7405-ENG-36
- OSTI ID:
- 348915
- Report Number(s):
- LA-UR-98-3973; ON: DE99002486; TRN: AHC29920%%66
- Resource Relation:
- Other Information: PBD: [1998]
- Country of Publication:
- United States
- Language:
- English
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