Diablo Canyon Power Plant’s two nuclear reactors are scheduled to shut down in 2024 and 2025. As of April 2018, Diablo Canyon’s two “spent” fuel pools held 1,800 irradiated nuclear fuel rods, and the Independent Spent Fuel Storage Installation (ISFSI) held 49 casks, each of which contains a maximum of 32 rods, for a total of more than 3,300 highly irradiated fuel rods stored on site.

Each day of operation, more nuclear waste is created. 

  • Diablo Canyon uses the Hi-Storm 100-SA casks with MPC-32 canisters. 
  • Plans call for loading and moving nine casks in 2018, and eight casks each in 2020 and 2022. It takes about one week to load, transport, and secure each cask.
  • The last NRC inspection of Diablo Canyon’s ISFSI was in the fall of 2016.  The next inspection is currently scheduled for summer 2018.

San Luis Obispo Mothers for Peace (SLOMFP) has grave concerns about how the high level radioactive waste will be stored on site after Diablo Canyon shuts down. This is a complex problem that needs very thoughtful and thorough consideration before any final decision is made.

Here are some established facts about high level nuclear waste stored at Diablo Canyon:

  1. According to the Environmental Protection Agency, the irradiated waste will be radioactive for at least 1,000,000 years.
  2. Radiation causes cancer, heart damage, mutations, genetic damage, spontaneous abortion, pre-term birth and has been linked to autoimmune diseases and other health issues.
  3. According to the National Academy of Sciences, there is no safe dose of radiation exposure.
  4. The current dry cask storage system emits radioactivity into the biosphere.
  5. The current Holtec Hi-Storm 100SA casks and MPC-32 canisters that store nuclear waste at Diablo Canyon are licensed for only 20 years. Some have been in use since 2009. The NRC has issued renewal licenses on dry cask storage up to 30 years.
  6. There is no designated location for final disposition of nuclear waste.

SLOMFP has taken all of these facts under consideration and recommends a course of action during the last years of operation and through decommissioning:

The irradiated nuclear waste at Diablo Canyon should stay on site for the foreseeable future. No permanent nuclear waste repository has been identified.

  1. Spent nuclear fuel (especially high-burnup fuel) has never been transported on America’s railways, highways or barges, and it would present significant dangers to the communities through which it would travel.
  2. Transporting nuclear waste to an “interim” storage site would cause it to be transported twice: once to the interim site, and then again to a permanent repository if one can be identified.
  3. The proposed “interim” storage sites in New Mexico and Texas are in poverty-stricken locations inhabited primarily by people of color, where there is little political clout - a clear case of environmental injustice.
  4. If the Department of Energy fails in its efforts to identify and build a permanent repository for nuclear waste, the interim storage sites would become de facto permanent sites. It is both unethical and irresponsible to ask another community to be burdened with the toxic waste that was created here on the Central Coast.
  5. See SLOMFP position papers on Consolidated Interim Storage and Yucca Mountain at https://mothersforpeace.org 

The irradiated nuclear waste at Diablo Canyon must be stored in more robust canisters. The Holtec MPC 32 canisters now being used at Diablo Canyon are licensed for only 20 years. Because the irradiated waste will probably be stored on site for many additional years, the high level waste should be in containers of the absolute highest quality.

  1. The stainless steel canisters used at Diablo Canyon have walls only ½ inch thick. Each canister holds 32 irradiated fuel rods.
  2. Prairie Island nuclear plant uses thick-walled canisters for their onsite storage. Also, the thick-walled casks at the Fukushima-Daiichi plant were unaffected by the earthquake and tsunami.
  3. The current Holtec canisters cannot be inspected or maintained because they are inside an overpack and cannot be viewed in their entirety.
  4. One canister at Diablo Canyon was found to have conditions for cracking in 2014 during an Electric Power Research Institute inspection, where salt deposits were found on the surface of the canister. That canister has not been re-inspected since.
  5. There is no method to repair a damaged canister once it has been filled with irradiated waste.
  6. The canister manufacturer, Holtec, loaded a mixture of high-burnup and low-burnup fuel contrary to NRC protocol in over half of the canisters at Diablo Canyon. This undermines SLOMFP’s confidence in methods to be used in the future as more irradiated fuel rods are loaded into dry casks.
  7. The NRC’s Generic Environmental Impact Statement for Continued Storage of Spent Nuclear Fuel Final Report states that a permanent repository may take decades or even centuries to establish. It also admits that there is no certainty such a repository may ever be created. SLOMFP concludes that it is therefore necessary to plan for the possibility that the waste may be stored onsite long-term or even permanently.

SLOMFP recommends the following:

  1. Secure the irradiated fuel in the absolute highest quality canisters and casks available.
  2. Move irradiated fuel out of the spent fuel pools and into dry cask storage as soon as possible, taking into consideration the need for high-burnup fuel to be cooled in pools for a longer duration.
  3. Secure canisters in temperature controlled, earthquake-hardened buildings with 24-hour radiation monitoring.
  4. Build a hot cell on site in case irradiated fuel must be transferred out of a cracked or leaking canister.
  5. Establish a regular monitoring schedule in which each canister is inspected in its entirety for possible leaks or cracks.
  6. Install publicly accessible 24-hour radiation monitoring around the periphery of the ISFSI.
  7. Maintain emergency planning and security services until all fuel is safely transported to a permanent repository, should one be established at some point in the future.