Pacific Gas & Electric Company (PG&E) plans to submit a new licence renewal application for its Diablo Canyon Power Plant (DCPP) - California's last nuclear power plant - to the US Nuclear Regulatory Commission (NRC) after the regulator said it will not resume its review of the previously submitted and subsequently withdrawn application.

Diablo Canyon (US Nuclear Regulatory Commission/PG&E)

PG&E submitted its application to renew the operating licences for the two pressurised water reactors in 2009, but withdrew it in 2018 after the California Public Utilities Commission (CPUC) approved a joint proposal from the company together with labour and leading environmental organisations to close the plant at the end of its current licences, in 2024 for unit 1 and 2025 for unit 2. At that time, it was thought that the plant's output would no longer be required as California focused on an energy policy centred on efficiency, renewables and storage - but grid reliability issues have prompted a rethink on the plant's early closure.

However, on 31 October last year, PG&E formally asked the NRC to resume its review of the licence renewal application for the Diablo Canyon plant after the state of California passed legislation that would enable the plant to continue operating until 2030. Senate Bill 846, which was signed on 2 September, will allow the units to operate for up to five years beyond 2025 to act as a bridging technology to ensure a reliable energy system and reduce greenhouse gas emissions until additional renewable and zero-carbon energy sources come online. It also includes a USD1.4 billion loan to PG&E.

The utility asked the NRC to resume its review of the licence renewal application "as it existed" when the review ceased in 2016, "including all associated correspondence and commitments".  PG&E said it would "develop and submit an amendment" to the previously withdrawn licence renewal application that identifies changes to the current licensing basis that materially affect the contents of the withdrawn application.

Alternatively, PG&E requested an exemption from 10 CFR 2.109(b), which provides that if a nuclear power plant licencee files a sufficient licence renewal application "at least 5 years before the expiration of the existing licence, the existing licence will not be deemed to have expired until the application has been finally determined". Specifically, the company requested timely renewal protection under 10 CFR 2.109(b) if it submitted a new licence renewal application for Diablo Canyon by 31 December 2023.

In a 24 January letter, the NRC told PG&E that "based on NRC regulations, NRC's Principles of Good Regulation, the lack of sufficient information to support your request that the staff resume its review of the withdrawn application, and the lack of relevant precedent to support that request, the NRC staff will not initiate or resume the review of the withdrawn DCPP application.

"This decision does not prohibit you from resubmitting your licence renewal application under oath and affirmation, referencing information previously submitted, and providing any updated or new information to support the staff's review."

The NRC added that it has not made a determination on PG&E's request for an exemption from 10 CFR 2.109(b). "The NRC staff is evaluating that exemption request and expects to provide a response in March 2023," it said.

Researched and written by World Nuclear News