Room at the Mountain
EPRI Analysis Finds Maximum Physical Capacity of Yucca Mountain Geological Repository is 4-9 Times Current Limit

An EPRI report analyzing expanded capacity options at the proposed Yucca Mountain geological repository for commercial spent nuclear fuel indicates that the technical capacity is four to nine times the current legal limit. Such a geological repository is one element of an integrated spent fuel management approach – encompassing on-site storage, interim storage, long-term central storage and possible reprocessing – designed to sustain long-term operation of existing U.S. nuclear power plants and facilitate projected expansion of nuclear power.

The report, Room at the Mountain (1015046), also provides preliminary cost estimates for expanding Yucca Mountain. Increasing the capacity from its current legal limit of 70,000 metric tons of heavy metals (MTHM) to 260,000 MTHM would result in costs only 28% higher than those for the existing repository design, on a net present value dollar basis. The full report is available here.

In a 2006 preliminary report on Yucca Mountain expansion opportunities, EPRI determined that the increased capacity could be achieved by expanding the repository area into adjacent, competent rock formations, and by increasing the loading density of spent fuel casks in a given area. For the 2007 report, EPRI conducted more detailed analysis of the thermal, hydrologic, and rock stability aspects of the higher loading density design than was available for the 2006 report. The additional EPRI work demonstrates that the higher loading density design can satisfy all temperature criteria and accommodate the construction and ventilation of additional disposal drifts.

The EPRI report indicates that Yucca Mountain could not only store all of the waste from existing U.S. nuclear power plants, but also waste produced from a significantly expanded U.S. nuclear power plant fleet for at least several decades. If all U.S. operating commercial nuclear reactors operated for 60 years, approximately 140,000 MTHM of commercial spent nuclear fuel would require disposal, including the existing spent fuel from reactors previously shut down. Further, even if the United States decides to close the nuclear fuel cycle through reprocessing and advanced reactors, the expanded Yucca Mountain capacity would allow time for the necessary R&D to accomplish a full-scale and economically competitive closed fuel cycle.