Fuel in both the wet and dry storage formats is stored in accordance with stringent requirements put into place by the US NRC. In the first quarter of 2020, PG&E issued a Request for Proposal (RFP) for a new spent fuel storage system to address how fuel is handled going forward. If this technology can be implemented, it would expedite the used fuel storage process by several years.
After nuclear fuel is used to produce electricity at Diablo Canyon, it is placed in wet storage pools located inside the plant's fuel handling building.
The fuel is then moved to the Independent Spent Fuel Storage Installation (ISFSI) site where it's safely stored in a dry storage format. This facility is located east of the power plant, and it has a separate license from the US Nuclear Regulatory Commission (NRC).
The fuel is stored at the Diablo Canyon ISFSI on an interim basis, as it will eventually be transferred to the federal government's repository - once established - for long-term storage.