Frictional sliding in layered rock: laboratory-scale experiments

The work is part of the rock mechanics effort for the Yucca Mountain Site Characterization Program. The laboratory-scale experiments are intended to provide high quality data on the mechanical behavior of jointed structures that can be used to validate complex numerical models for rock-mass behavior. Frictional sliding between simulated rock joints was studied using phase shifting moire interferometry. A model, constructed from stacks of machined and sandblasted granite plates, contained a central hole bore normal to the place so that frictional slip would be induced between the plates near the hole under compressive loading. Results show a clear evolution of slip with increasing load. Since the rock was not cycled through loading- unloading, the quantitative differences between the three data sets are probably due to a ``wearing-in`` effect. The highly variable spatial frequency of the data is probably due to the large grain size of the granite and the stochastic frictional processes. An unusual feature of the evolution of slip with increasing load is that as the load gets larger, some plates seem to return to a null position. Figs, 6 refs

Severe fuel-damage scoping test performance. [PWR]

As a result of the Three Mile Island Unit-2 (TMI-2) accident, the Nuclear Regulatory Commission has initiated a severe fuel damage test program to evaluate fuel rod and core response during severe accidents similar to TMI-2. The first test of Phase I of this series has been successfully completed in the Power Burst Facility at the Idaho National Engineering Laboratory. Following the first test, calculations were performed using the TRAC-BD1 computer code with actual experimental boundary conditions. This paper discusses the test conduct and performance and presents the calculated and measured test bundle results. The test resulted in a slow heatup to 2000 K over about 4 h, with an accelerated reaction of the zirconium cladding at temperatures above 1600 K in the lower part or the bundle and 2000 K in the upper portion of the bundle

Frictional sliding in layered rock model: Preliminary experiments. Yucca Mountain Site Characterization Project

An important aspect of determining the suitability of Yucca Mountain as a possible nuclear waste repository requires understanding the mechanical behavior of jointed rock-masses. To this end we have studied the frictional sliding between simulated rock joints in the laboratory using the technique of phase shifting moire interferometry. The models were made from stacks of Lexan plates and contained a central hole to induce slip between the plates when the models were loaded in compression. These preliminary results confirm the feasibility of the approach and show a clear evolution of slip as function of load

Post test investigation of the bundle test ESBU-1 On temperature escalation in PWR fuel rod simulator bundles due to the Zircaloy/steam reaction

SIGLECopy held by FIZ Karlsruhe; available from UB/TIB Hannover / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman

Influence of controlled atmosphere storage on polyphenoloxidase activity in relation to colour changes of minimally processed ‘Jonagored’ apple

The effects of the storage atmosphere composition (2% O2 + 4% CO2; 2% O2 + 8% CO2; 2% O2 + 12% CO2) on polyphenoloxidase activity and phenolic content of the ‘Jonagored’ apple variety during cold storage was evaluated, and the relationship with enzymatic browning investigated. Controlled atmosphere storage inhibited the polyphenoloxidase (PPO) activity of apple cubes during storage. It seems that the higher the concentration of carbon dioxide in the storage atmosphere the higher inhibition of PPO and the lower browning achieved. At the substrate-enzyme levels investigated, the phenolic content, substrate level was the major factor determining darkening