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In the design of a spent nuclear fuel disposal system, one necessary condition is to show that the configuration remains subcritical at time of emplacement but also during long periods covering up to 1,000,000 years. In the context of criticality safety applying burn-up credit, k-eff eigenvalue calculations are affected by nuclear data uncertainty mainly in the burnup calculations simulating reactor operation and in the criticality calculation for the disposal canister loaded with the spent fuel assemblies. The impact of nuclear data uncertainty should be included in the k-eff value estimation to enforce safety. Estimations of the uncertainty in the discharge compositions from the CASMO5 burn-up calculation phase are employed in the final MCNP6 criticality computations for the intact canister configuration; in between, SERPENT2 is employed to get the spent fuel composition along the decay periods. In this paper, nuclear data uncertainty was propagated by Monte Carlo sampling in the burn-up, decay and criticality calculation phases and representative values for fuel operated in a Swiss PWR plant will be presented as an estimation of its impact. [ABSTRACT FROM AUTHOR]

Friction, and consequently heat generation in the cutting zone, significantly affects the tool life, surface integrity and dimensional accuracy, apart from other machining results. Application of a coolant in a cutting process can increase tool life and dimensional accuracy, decrease heat generation, and consequently cutting temperatures, reduce surface roughness and the amount of energy consumed in cutting process, and thus improve the productivity. Furthermore, coolant application also affects the surface microstructural alterations (i.e., white and dark layers) due to a machining operation, which have a significant influence on product performance and life. This paper presents the results of an experimental investigation to determine the effects of cryogenic coolant application on tool wear, cutting forces and machined surface alterations during orthogonal machining of hardened AISI 52100 bearing steel (54±1 HRC). Experiments were performed for dry and cryogenic cutting conditions using chamfered PCBN tool inserts at varying cutting conditions (cutting speed and feed rate). For cryogenic cutting conditions the fluid was applied in the form of a liquid nitrogen jet directed on the three shear cutting zones. Cutting forces, tool wear, cutting temperatures, surface hardness modifications and microstructure alterations were studied in order to evaluate the effects of extreme in-process cooling. The results indicate that cryogenic cooling has the potential to be used for surface integrity enhancement for improved product life and more sustainable functional performance. [ABSTRACT FROM AUTHOR]