Overview of design considerations for effective trench covers

The siting, design, and operation of low-level radioactive waste disposal facilities are directed toward the isolation of waste. Isolation of waste from surface and ground water is the main concern for disposal sites, particularly those located in humid regions. For sites that satisfy the minimum technical requirements for siting, surface water control becomes the key factor in isolating buried waste. Trench covers are an integral part of the site's surface water control plan and function with other elements of disposal site to reduce surface water infiltration, and contribute to overall isolation of the buried waste. Attributes of a good cover design include constructibility, utilization of readily available materials, cost effectiveness, long-term reliability, and low maintenance. Thorough knowledge of the site's environmental, geological, and hydrological conditions, and familiarity with the proposed site layout, site development sequence, and disposal operations are important prerequisites for effective trench cover design. In the final analysis, trench cover performance depends on the successful implementation of the construction design and the cover's compatibility with trench geometry, site conditions, disposal operations, and the overall surface water control plan