By John Stang
A proposed settlement agreement contends that decommissioning of the Diablo Canyon nuclear power plant in California later this decade can be done for $900 million less than previously estimated.
On Jan. 10, plant owner Pacific Gas & Electric Co., San Luis Obispo County, and five other entities filed a proposed settlement agreement on their previously separate positions on the utility’s Diablo Canyon Decommissioning Planning Memorandum Account.
In 2018, PG&E applied for authorization from the California Public Utilities Commission (CPUC) to establish the account to monitor decommissioning expenses ahead of a still-future state decision on increasing customer rates to pay for cleanup at the plant.
The proposed settlement agreement puts a $3.9 billion price tag for decommissioning the reactor complex. Right now, the cost estimate is $4.8 billion. The proposed settlement calls for trimming $300 million via a reduced used fuels cooling period in wet storage, trimming $200 million by keeping some non-nuclear buildings intact, and trimming $400 million by not demolishing an offshore breakwater system containing 686,210 tons of concrete that is mostly underwater.
Under its prior cost estimate, PG&E had estimated in December 2018 it would need $1.6 billion from ratepayer to fully pay for decommissioning of the state’s last operational power plant. That would increase residential bills by $1.98, according to local reports at the time. A lower cost for decommissioning presumably would translate to a reduction in the added costs for customers.
In paperwork filed in December with the Nuclear Regulatory Commission in December, PG&E broke down the cleanup costs at Diablo Canyon: $3.16 billion for decommissioning, $1.26 billion for spent fuel management, and about $738,000 for site restoration. It projected decommissioning would begin after full closure in 2025 and wrap up by 2038.
The other signatories to the settlement agreement are The Utility Reform Network, CPUC’s Public Advocates Office, the Alliance for Nuclear Responsibility, the Northern Chumash Cultural Preservation Kinship, and Women’s Energy Matters. The entities other than PG&E had concerns about the calculations and distribution of Diablo Canyon’s decommissioning trust fund.
“We are committed to a safe and sure decommissioning of Diablo Canyon,” said PG&E spokeswoman Suzanne Hosn.
As of Oct. 31, 2019, PG&E had $3.63 billion in its decommissioning trust fund for Reactors. No 1 and No. 2 at Diablo Canyon. This money is protected from PG&E’s current Chapter 11 bankruptcy proceedings, Hosn said.
In 2016, PG&E announced it would close Diablo Canyon as the federal licenses for its two reactors expire – Unit 1 in 2024 and Unit 2 in 2025. It has said it will replace the facility with other forms of clean energy.
The company previously planned to complete the transfer of spent fuel to dry storage in June 2032. The proposed settlement agreement calls for that movement to dry storage to be completed four years after the second reactor closes in 2025 — essentially meaning 2029.
Diablo Canyon currently has 1,856 fuel assemblies in 58 canisters in dry storage. Another 1,596 fuel assemblies are in storage pools, plus 386 assemblies still in use in the two reactors. Each reactor will be refueled three more times prior to closure. PG&E estimates that it will ultimately have 138 casks in dry storage.
The settlement agreement also calls for PG&E to nail down a decommissioning strategy and to obtain bids on the near-term works in 2021.
It further calls for a comparison in 2021 between costs for Diablo Canyon and the similar decommissioning of the retired San Onofre Nuclear Generating Station (SONGS) further south. Owner Southern California Edison permanently shut down SONGS’ last two reactors in 2013, and major decommissioning operations are beginning this year under an AECOM-EnergySolutions joint venture. That project is due for completion by 2028 at an estimated cost of $4.1 billion.
A CPUC administrative judge will likely issue a proposed decision on the Diablo Canyon agreement in late spring or summer, after possibly taking in extra comments from the parties to the settlement agreement, said commission spokesman Christopher Chow. Once a judge unveils a proposed decision, at least 30 days must be set aside for public comment before the commission can vote on accepting the recommended decision.
