Effect of self-irradiation on the resistivity of plutonium

Lee, J.A.; Mendelssohn, K.; Wigley, D. A.

doi:10.1016/0031-9163(62)90412-2

Cited by 29 publications

(8 citation statements)

References 4 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Recent transmission electron microscopy investigation of aged Pu-Ga alloys revealed the presence of nanometer-sized helium bubbles formed from helium in-growth [7]. However, most experiments on self-irradiation damage in plutonium (for example, resistivity measurements [2,8,9]) have been conducted at cryogenic temperatures over very short time periods where very little annealing occurs and do not represent the plutonium aging behavior at ambient temperature.…”

Section: Introductionmentioning

confidence: 99%

Density changes in plutonium observed from accelerated aging using Pu-238 enrichment

Chung

Thompson

Woods

et al. 2006

Journal of Nuclear Materials

View full text Add to dashboard Cite

In support of Stockpile Stewardship activities, accelerated aging tests on a plutonium alloy enriched with 7.3 atomic percentage of 238 Pu is underway using dilatometry at 35, 50, and 65°C and immersion density measurements of material stored at 50°C. Changes in density are expected from radiation damage in the lattice and helium in-growth. After twenty-five equivalent years of aging, the dilatometry data shows that the alloys at 35°C have expanded in volume by 0.11% to 0.12% and have started to exhibit a near linear expansion behavior primarily caused by the helium accumulation. The average He-tovacancy ratio from tested specimens was determined to be around 2.3. The model for the lattice damage and helium in-growth accurately represents the volume swelling at 35°C.The density converted from the dilatometry corresponds well to the decreasing density trend of reference plutonium alloys as a function of time.

show abstract

Section: Introductionmentioning

confidence: 99%

Density changes in plutonium observed from accelerated aging using Pu-238 enrichment

Chung

Thompson

Woods

et al. 2006

Journal of Nuclear Materials

View full text Add to dashboard Cite

show abstract

“…By contrast, the U recoil travels only Ϸ0.012 m initiating a dense displacement cascade of Ϸ2,300 vacancies and interstitials, Ϸ70% of which are estimated to recombine (17) during the following tens of picoseconds as the lattice rapidly cools. Previous work (18)(19)(20)(21) examined changes in resistivity and volume attributable to self-damage in plutonium. Recently, the temperaturedependence of the resistivity of vacancies and vacancy clusters Pu(Ga) was shown to exhibit a Ϫln(T) behavior, suggesting a defect-induced Kondo-like behavior (22), analogous to that seen in hole-doped superconductors subjected to electron irradiation (16).…”

mentioning

confidence: 99%

Emergent magnetic moments produced by self-damage in plutonium

McCall

Fluss

Chung

et al. 2006

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

Plutonium possesses the most complicated phase diagram in the periodic table, driven by the complexities of overlapping 5f electron orbitals. Despite the importance of the 5f electrons in defining the structure and physical properties, there is no experimental evidence that these electrons localize to form magnetic moments in pure Pu. Instead, a large temperature-independent Pauli susceptibility indicates that they form narrow conduction bands. Radiation damage from the ␣-particle decay of Pu creates numerous defects in the crystal structure, which produce a significant temperature-dependent magnetic susceptibility, (T), in both ␣-Pu and ␦-Pu (stabilized by 4.3 atomic percent Ga). This effect can be removed by thermal annealing above room temperature. By contrast, below 35 K the radiation damage is frozen in place, permitting the evolution in (T) with increasing damage to be studied systematically. This result leads to a two-component model consisting of a Curie-Weiss term and a short-ranged interaction term consistent with disorder-induced local moment models. Thus, it is shown that self-damage creates localized magnetic moments in previously nonmagnetic plutonium.disorder ͉ magnetism ͉ radiation damage A mong the interesting properties of plutonium is a complex phase diagram, which at ambient pressure exhibits six distinct solid-state phases below the melting temperature. These phases are narrowly spaced in energy, with the five lowest-energy phases separated by Ͻ2 mRyd, placing them on a molecularenergy scale as compared with the more typical 10-20 mRyd scale typical of metals such as neighboring Np and Am (1). Although there is no theoretical consensus as to the origin of the low-density fcc ␦-phase of Pu (1-7), there is an understanding that the organization of the spin and orbital moments play a key role in stabilizing this phase. The lack of significant magnetic moments is a central issue among theorists and inspired a recent experimental review (8) painstakingly describing the evidence against the existence of magnetic moments in plutonium. Recent SR ϩ studies for ␣-and ␦-phase Pu further support this absence of magnetic moments, placing the upper bound on frozen moments at 0.001 Bohr magneton ( B ) (9). However, all solid Pu phases possess large magnetic susceptibilities, suggesting they border on becoming magnetic. Consistent with this observation and general predictions of narrow 5f bands in plutonium are large electronic contributions to the specific heat in both ␣-Pu and alloy-stabilized ␦-Pu, qualifying each as a highly correlated electron system (10).Often, local magnetic moments can be induced in nearly magnetic systems by imposing a suitable perturbation. One such method is to increase disorder by introducing a low concentration of impurities via chemical substitution. For example, when very dilute quantities of Fe, Co, or Ni are doped into nonmagnetic Pd, they induce remarkably large magnetic moments by polarizing the surrounding lattice (11,12). Similarly, one-half atomic percent (at. %) Pu do...

show abstract

“…Isochronal annealing experiments using electrical resistivity have been used as a method of determining the temperatures where accumulated defects from radiation damage become mobile. Lee et al [31], Elliott et al [32], and Wigley [33] The questions here suggest various possibilities of property changes related to the onset of the early stages of the eutectoid reaction, δ → α + Pu 3 Ga, which have not been considered important in the literature because of the implied long term sluggishness of his reaction (~10,000 years). The recently published "δ conditioning" experiments at 25°C [36] discussed below, and the volume changes and electrical resistivity changes at 150 -170°C suggest that the eutectoid reaction may be at least a partial reason for these changes, and hence that a pursuit of a much better understood explanation of the kinetics of the eutectoid decomposition is essential.…”

Section: α-Decaymentioning

confidence: 92%

Opportunities in Plutonium Metallurgical Research*

Schwartz

2006

MRS Proc.

View full text Add to dashboard Cite

This is an exciting time to be involved in plutonium metallurgical research. Over the past few years, there have been significant advances in our understanding of the fundamental materials science of this unusual metal, particularly in the areas of self-irradiation induced aging of Pu, the equilibrium phase diagram, the homogenization of δ-phase alloys, the crystallography and morphology of the α'-phase resulting from the isothermal martensitic phase transformation, and the phonon dispersion curves, among many others. In addition, tremendous progress has been made, both experimentally and theoretically, in our understanding of the condensed matter physics and chemistry of the actinides, particularly in the area of electronic structure. Although these communities have made substantial progress, many challenges still remain. This brief overview will address a number of important challenges that we face in fully comprehending the metallurgy of Pu with a specific focus on aging and phase transformations.

show abstract

Effect of self-irradiation on the resistivity of plutonium

Cited by 29 publications

References 4 publications

Density changes in plutonium observed from accelerated aging using Pu-238 enrichment

Density changes in plutonium observed from accelerated aging using Pu-238 enrichment

Emergent magnetic moments produced by self-damage in plutonium

Opportunities in Plutonium Metallurgical Research*

Contact Info

Product

Resources

About