Selection of Batteries and Fuel Cells for Yucca Mountain Robots

摘要

The Performance Confirmation program of the Yucca Mountain Repository Development Project needs to employ remotely operated robots to work inside the emplacement drifts which will have an environment unsuitable for humans (radiation environment of up to 200 rad/hour)(mostly gamma rays, some neutrons) and maximum temperatures of 180 deg C. The robots will be required to operate inside the drifts for up to 8 hours per mission. Based on available functional requirements, we have developed the following specifications for the power needed by the robots: Each robot will need a sustained power of 100 W for 8 hours. During that time, for a combined period of 60 minutes, the robots may need 1000 W power. Thus the total energy required by the robots is 1700 W-hr at nominal sustained load of 100 W and peak load of 1000 W. There are currently no commercially available batteries that meet the specifications of temperature and radiation flux. Most commercial batteries are designed to operate at ambient temperature. Some batteries, such as zinc/air or aluminum/air, designed for ambient temperature, are theoretically capable of being operated at higher temperatures, however, significant R&D will be required to realize their high temperature potential. In any case, their radiation tolerance remains unknown. We have investigated a number of batteries, and downselected four of them as potential candidates for the Yucca Mountain Project. We describe them under the section on batteries. We have compared a number of fuel cells for the required service at Yucca Mountain. Out of the seven fuel cells we considered, we have downselected three as potential candidates for service in Yucca Mountain. The details of these considerations are given under the section on fuel cells. We will investigate the radiation tolerance of Phosphoric Acid Fuel Cells (PAFCs) by subjecting them to increasing levels of gamma-ray radiation, and characterizing their performance after each radiation treatment using a proprietary micro-fuel-cell developed at Lawrence Livermore National Laboratory (LLNL). We will describe the construction of the PAFC, followed by the description of the process used to characterize them under the section on radiation resistant fuel cells.