Status Report on Fast Reactor Recycle and Impact on Geologic Disposal

Wigeland, R. A.; Bauer, T H; Morris, E E

doi:10.2172/912460

Cited by 7 publications

(16 citation statements)

References 3 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…As temperature increases, the significance of − T Δ S sub also rises. Consider T = 400 °C, which is within the temperature range of nuclear waste repositories storing spent nuclear fuel. , For Ca,Th:YIGs, see Figure b, the stability region for Th content in the system extends to 0.4 apfu, beyond which the free energies of substitution at 400 °C (Δ G 400 °C sub , Table ) are positive. Similarly, Ca,Ce:YIG extends its stability region to 0.3 apfu of Ce.…”

Section: Discussionmentioning

confidence: 99%

Charge-Coupled Substituted Garnets (Y_3–xCa_0.5xM_0.5x)Fe₅O₁₂ (M = Ce, Th): Structure and Stability as Crystalline Nuclear Waste Forms

Guo

Kukkadapu

Lanzirotti³

et al. 2015

Inorg. Chem.

View full text Add to dashboard Cite

The garnet structure has been proposed as a potential crystalline nuclear waste form for accommodation of actinide elements, especially uranium (U). In this study, yttrium iron garnet (YIG) as a model garnet host was studied for the incorporation of U analogs, cerium (Ce) and thorium (Th), incorporated by a charge-coupled substitution with calcium (Ca) for yttrium (Y) in YIG, namely, 2Y(3+) = Ca(2+) + M(4+), where M(4+) = Ce(4+) or Th(4+). Single-phase garnets Y3-xCa0.5xM0.5xFe5O12 (x = 0.1-0.7) were synthesized by the citrate-nitrate combustion method. Ce was confirmed to be tetravalent by X-ray absorption spectroscopy and X-ray photoelectron spectroscopy. X-ray diffraction and (57)Fe-Mössbauer spectroscopy indicated that M(4+) and Ca(2+) cations are restricted to the c site, and the local environments of both the tetrahedral and the octahedral Fe(3+) are systematically affected by the extent of substitution. The charge-coupled substitution has advantages in incorporating Ce/Th and in stabilizing the substituted phases compared to a single substitution strategy. Enthalpies of formation of garnets were obtained by high temperature oxide melt solution calorimetry, and the enthalpies of substitution of Ce and Th were determined. The thermodynamic analysis demonstrates that the substituted garnets are entropically rather than energetically stabilized. This suggests that such garnets may form and persist in repositories at high temperature but might decompose near room temperature.

show abstract

Section: Discussionmentioning

confidence: 99%

Charge-Coupled Substituted Garnets (Y_3–xCa_0.5xM_0.5x)Fe₅O₁₂ (M = Ce, Th): Structure and Stability as Crystalline Nuclear Waste Forms

Guo

Kukkadapu

Lanzirotti³

et al. 2015

Inorg. Chem.

View full text Add to dashboard Cite

show abstract

“…The PRISM Probabilistic Risk Assessment [5] shows the impact of probabilistic uncertainty upon advanced reactor risks -a cliff-edge risk profile wherein the likelihoods of relatively small consequences (e.g., one to 10 latent fatality) are nearly the same as for moderate to high consequences (e.g., 10 to 1000 latent fatalities), with a significant and rapid drop in likelihood as the number of consequences increases to extremely high levels (see Figure 1.1). Advanced reactors tend to have lower overall safety risks than Light Water Reactors, but certain very lowprobability events (e.g., extended loss of decay heat removal) could cause radiation release to increase from de minimums to significant levels.…”

Section: Why Study Accident Managementmentioning

confidence: 99%

“…2. Expert elicitation that EM pumps quickly degraded above the EM pump trip set-point due to insulation degradation and subsequent damage to the magnets and other electrical components[5]. 3.…”

mentioning

confidence: 99%

Risk Management for Sodium Fast Reactors.

Denman

Groth

Cardoni

et al. 2015

View full text Add to dashboard Cite

Accident management is an important component to maintaining risk at acceptable levels for all complex systems, such as nuclear power plants. With the introduction of self-correcting, or inherently safe, reactor designs the focus has shifted from management by operators to allowing the system's design to manage the accident. While inherently and passively safe designs are laudable, extreme boundary conditions can interfere with the design attributes which facilitate inherent safety, thus resulting in unanticipated and undesirable end states. This report examines an inherently safe and small sodium fast reactor experiencing a beyond design basis seismic event with the intend of exploring two issues: (1) can human intervention either improve or worsen the potential end states and (2) can a Bayesian Network be constructed to infer the state of the reactor to inform (1).

show abstract

“…Recent studies by ourselves [4,5,6] and others [7,8,9] have examined several nuclear materials systems in which alpha-decay is not present and the only radioactive process is beta-decay. These works were motivated by modern considerations in nuclear waste storage such as the recent work of Wigeland et al [10] who showed that geological repositories could increase their capacity by more than a hundred-fold if a handful of critical isotopes were chemically extracted from the spent nuclear fuel. There are two main isotope groups in question: (i) "short-lived" beta-emitters, 137 Cs and 90 Sr, with a half-life of around 30 years, and (ii) transuranics, principally Pu, Am and Cm.…”

Section: Introductionmentioning

confidence: 99%

Chemical evolution via beta decay: a case study in strontium-90

Marks

Carter

Sassi

et al. 2013

J. Phys.: Condens. Matter

View full text Add to dashboard Cite

Using (90)Sr as a representative isotope, we present a framework for understanding beta decay within the solid state. We quantify three key physical and chemical principles, namely momentum-induced recoil during the decay event, defect creation due to physical displacement, and chemical evolution over time. A fourth effect, that of electronic excitation, is also discussed, but this is difficult to quantify and is strongly material dependent. The analysis is presented for the specific cases of SrTiO(3) and SrH(2). By comparing the recoil energy with available threshold displacement data we show that in many beta-decay situations defects such as Frenkel pairs will not be created during decay as the energy transfer is too low. This observation leads to the concept of chemical evolution over time, which we quantify using density functional theory. Using a combination of Bader analysis, phonon calculations and cohesive energy calculations, we show that beta decay leads to counter-intuitive behavior that has implications for nuclear waste storage and novel materials design.

show abstract

Status Report on Fast Reactor Recycle and Impact on Geologic Disposal

Cited by 7 publications

References 3 publications

Charge-Coupled Substituted Garnets (Y_3–xCa_0.5xM_0.5x)Fe₅O₁₂ (M = Ce, Th): Structure and Stability as Crystalline Nuclear Waste Forms

Charge-Coupled Substituted Garnets (Y_3–xCa_0.5xM_0.5x)Fe₅O₁₂ (M = Ce, Th): Structure and Stability as Crystalline Nuclear Waste Forms

Risk Management for Sodium Fast Reactors.

Chemical evolution via beta decay: a case study in strontium-90

Contact Info

Product

Resources

About

Status Report on Fast Reactor Recycle and Impact on Geologic Disposal

Cited by 7 publications

References 3 publications

Charge-Coupled Substituted Garnets (Y3–xCa0.5xM0.5x)Fe5O12 (M = Ce, Th): Structure and Stability as Crystalline Nuclear Waste Forms

Charge-Coupled Substituted Garnets (Y3–xCa0.5xM0.5x)Fe5O12 (M = Ce, Th): Structure and Stability as Crystalline Nuclear Waste Forms

Risk Management for Sodium Fast Reactors.

Chemical evolution via beta decay: a case study in strontium-90

Contact Info

Product

Resources

About

Charge-Coupled Substituted Garnets (Y_3–xCa_0.5xM_0.5x)Fe₅O₁₂ (M = Ce, Th): Structure and Stability as Crystalline Nuclear Waste Forms

Charge-Coupled Substituted Garnets (Y_3–xCa_0.5xM_0.5x)Fe₅O₁₂ (M = Ce, Th): Structure and Stability as Crystalline Nuclear Waste Forms