Granites safety

In 1976 the Swedish government stipulated that no new nuclear reactors should be charged until it had been shown how the radioactive waste products could be taken care of in an "absolutely safe manner" (8). Consequently, the nuclear power industry (through their joint Nuclear Fuel Supply Co, SKBF) embarked on a program referred to as the Nuclear Fuel Safety (KBS) Project (8). In one of the schemes (9) a repository for spent nuclear fuel elements in envisaged at a depth of 500 m in granitic bedrock. The repository will ultimately contain 6000 tonnes of uranium and 45 tonnes of plutonium. The spent fuel elements will be stored in copper cylinders (0.8 m in diameter and 4.7 m in length) with a wall thickness of 200 mm the void will be filled with lead. 

A general conclusion from the review of the distribution of plutonium between different compartments of the ecosystem was that the enrichment of plutonium from water to food was fairly well compensated for by man s metabolic discrimination against plutonium. Therefore, under the conditions described above, it may be concluded that plutonium from a nuclear waste repository in deep granite bedrock is not likely to reach man in concentrations exceeding permissible levels. However, considering the uncertainties in the input equilibrium constants, the site-specific Kd-values and the very approximate transport equation, the effects of the decay products, etc. — as well as the crude assumptions in the above example — extensive research efforts are needed before the safety of a nuclear waste repository can be scientifically proven. 

Erdal, B.R. Aguilar, R.D. Bayhurst, B.P. Daniels, W.R. Duffy, C.J. Lawrence, F.O. Maestas, S. Oliver, P.Q. Wolfsberg, K. "Sorption-Desorption Studies on Granite. I. Initial Studies of Strontium, Technetium, Cesium, Barium, Cerium, Europium, Uranium, Plutonium, and Americium", in "Proceedings of the Task 4 Waste Isolation Safety Assessment Program Second Contractor Information Meeting", Vol. II, Report PNL-SA-7352, Battelle Pacific Northwest Laboratory, 1978, pp. 7-67. 

The isolation and safety functions of HLNW deep geological repositories are based upon the multibarrier concept, where a number of containment and isolation barriers are put in place. A schematic view of the multibarrier HLNW concept is given in Fig. 1. The main barriers of the system are the waste matrix itself a metallic container (either corrosion resistant like Cu or Ti, or based upon stainless steel) a buffer material (normally bentonite) and finally the host rock itself (essentially granite or clay, although salt domes are also being considered). 

Degueldre, C. 1993. Colloid properties in granitic ground-water systems, with emphasis on the impact on safety assessment. Mat. Res. Soc. symp. proc. 294, 817-23. 

In this paper, we provided the rationale and definition of a benchmark test called BMTl to look at the implications of THM couplings on safety parameters in the near field of a hypothetical repository. This hypothetical repository possesses composite features since it is based on a Japanese design, with a Japanese bentonite used as buffer material and the heat output characteristics of Japanese spent fuel. However, the permeability and strength characteristics of the rock mass are based on typical properties of granites of the Canadian Shield. 

Molybdenite or molybdenum disulfide (M0S2) or molysulfide is a mineral [5] found in granites, syenites, gneisses, and crystalline limestones. A NIOSH (National Institute for Occupational Safety and Health) web site [6] has listed a total of 31 synonyms for molybdenite. The use of molybdenite as a lubricant was apparently recorded in the early seventeenth century by John Andrew Cramer 7]. Chrysler, an automotive manufacturer, was the first to widely use M0S2 grease in the 1960s. 

Designers may want to use traditional granite setts as a road surface while Road Safety Auditors want adequate skid-resistant surfaces to enable drivers to stop safely. 

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