Ever since PG&E formally announced its intention to close down the Diablo Canyon Power Plant (DCPP) in 2025, two general threads of public response have been manifested. One thread, characterized, inter alia, by a recent Michael Schellenberger OpEd in The New York Times argues that solar and wind power will not suffice to fill the 9% gap in California’s electrical energy demand that would ensue, and that nuclear energy is the cleanest available alternative. Others express their delight that the potential Fukushima-like risk that might follow a major earthquake or tsunami would thereby be removed.
Neither position pays sufficient attention to the question of whether and how the spent nuclear fuel generated at DCPP and still stored on site would be disposed of. As is the case with all discussions of high level nuclear waste disposal for the past several decades, there is much talk but little action. It should be recalled that the most serious long-term threat at Fukushima arose from the loss of coolant at spent fuel pool #4. Although the spent fuel pools at DCPP are not as poorly located as those at Fukushima were, they will remain at the site for at least three decades after the plant shuts down. At least that is the optimistic forecast.
Consider this excerpt from PG&E Letter DIL-15-026 , dated December 17, 2015 to the Director,
Division of Spent Fuel Storage and Transportation Office of Nuclear Material Safety and Safeguards U.S. Nuclear Regulatory Commission.
The operating license for DCPP Units 1 and 2 are currently set to expire on November 2, 2024, and August 26, 2025, respectively. Approximately 4,416 spent fuel assemblies are currently projected to be generated as a result of plant operations through these license expiration dates. The ISFSI is operated under a Part 72 Site Specific License.
Assuming that the plant operates to the end of currently licensed life the spent fuel pools are expected to contain up to 2,272 spent fuel assemblies after the final core offloads. To facilitate immediate dismantling or safe-storage operations, the spent fuel that cannot be transferred directly to the Department of Energy (DOE) from the pool is assumed to be packaged in dry storage casks for interim storage at the ISFSI. Transferring the spent fuel from the pool to the ISFSI will permit decontamination and dismantling of the spent fuel pool systems and fuel pool areas or result in reduced operating expenses should the station be placed into a SAFSTOR dormancy confi'guration. Completion of the ISFSI decommissioning process is dependent upon the DOE's ability to remove spent fuel from the site. DOE's repository program assumes that spent fuel allocations will be accepted for disposal from the nation's commercial nuclear plants, with limited exceptions, in the order (the "queue") in which it was discharged from the reactor. Pacific Gas and Electric's (PG&E's) current spent fuel management plan for the DCPP spent fuel is based in general upon: 1) a 2024 start date for DOE initiating transfer of commercial spent fuel to a federal facility, and 2) completion of spent fuel receipt by year 2055. The completion date is based upon the DOE's generator allocation/receipt schedules which are based upon the oldest fuel receiving the highest priority. Assuming a maximum rate of transfer of 3,000 metric tons of uranium/year, the spent fuel is projected to be removed from the DCPP site in 2055.
With all due respect to both PG&E and the DOE, there are many assumptions underlying this schedule, including DOE’s development of a spent fuel removal and disposal program that is publicly and politically acceptable. That is something that has eluded Congress and the Department for more than four decades, primarily because they continue to regard it as primarily a technical issue rather than a social one. Until/unless that changes, progress is doubtful.