Nonlinear dynamics of self-sustained supersonic reaction waves: Fickett's detonation analogue

The present study investigates the spatio-temporal variability in the dynamics of self-sustained supersonic reaction waves propagating through an excitable medium. The model is an extension of Fickett's detonation model with a state dependent energy addition term. Stable and pulsating supersonic waves are predicted. With increasing sensitivity of the reaction rate, the reaction wave transits from steady propagation to stable limit cycles and eventually to chaos through the classical Feigenbaum route. The physical pulsation mechanism is explained by the coherence between internal wave motion and energy release. The results obtained clarify the physical origin of detonation wave instability in chemical detonations previously observed experimentally.Comment: 4 pages, 3 figure

Dose Rate Calucaltion for the DHL W/DOE SNF Codisposal Waste Package

The purpose of this calculation is to determine the surface dose rates of the short codisposal waste package (WP) of defense high-level waste (DHLW) and TRIGA (Training, Research, Isotopes, General Atomics) spent nuclear fuel (SNF). The WP contains the TRIGA SNF, in a standardized 18-in. DOE (U.S. Department of Energy) SNF canister, and five 3-m-long Savannah River Site (SRS) DHLW pour glass canisters, which surround the DOE SNF canister

Dose Rate Calculations for the 2-MCO/2-DHLW Waste Package

The objective of this calculation is to determine the dose rates on the external surfaces of the waste package (WP) containing two Hanford defense high-level waste (DHLW) glass canisters and two Hanford multi-canister overpacks (MCO). Each MCO is loaded with the N Reactor spent nuclear fuel (SNF). The information provided by the sketches attached to this calculation is that of the potential design for the WP type considered in this calculation. The scope of this calculation is limited to reporting dose rates averaged over segments of the WP radial and axial surfaces and of surfaces 1 m and 2 m from the WP. The results of this calculation will be used to assess the shielding performance of the 2-MC012-DHLW WP engineering design

Dose Calculations for the Codsiposal WP of HLW Glass and the Shippingport LWBR SNF

The purpose of this calculation is to determine the surface dose rates of a codisposal waste package (WP) containing an intact seed assembly of the Shippingport light-water breeder reactor (LWBR) spent nuclear fuel (SNF) and the Savannah River Site (SRS) high-level waste (HLW) in glass form. The Shippingport LWBR SNF is loaded in a Department of Energy (DOE) standardized 18-in. canister. The canister is surrounded by five 4.5-m-long Hanford pour canisters containing the HLW glass. Gamma dose rate calculation for the WP containing only the HLW glass is also performed. The results will provide information about the contribution of DOE SNF to the total dose rate on the WP surfaces

Dose Calculations for the Co-Disposal WP-of HLW-Glass and the Triga SNF

This calculation is prepared by the Monitored Geologic Repository (MGR) Waste Package Operations (WPO). The purpose of this calculation is to determine the surface dose rates of a codisposal waste package (WP) containing a centrally located Department of Energy (DOE) standardized 18-in. spent nuclear fuel (SNF) canister, loaded with the TRIGA (Training, Research, Isotopes, General Atomics) SNF. This canister is surrounded by five 3-m long canisters, loaded with Savannah River Site (SRS) high-level waste (HLW) glass. The results are to support the WP design and radiological analyses

Time scales in shear banding of wormlike micelles

Transient stress and birefringence measurements are performed on wormlike micellar solutions that "shear band", i.e. undergo flow-induced coexistence of states of different viscosities along a constant stress "plateau". Three well-defined relaxation times are found after a strain rate step between two banded flow states on the stress plateau. Using the Johnson-Segalman model, we relate these time scales to three qualitatively different stages in the evolution of the bands and the interface between them: band destabilization, reconstruction of the interface, and travel of the fully formed interface. The longest timescale is then used to estimate the magnitude of the (unknown) "gradient" terms that must be added to constitutive relations to explain the history independence of the steady flow and the plateau stress selection