California has taken its most significant step in decades toward reconsidering nuclear power. Gov. Gavin Newsom signed Assembly Bill 2647 on Sept. 30, requiring the California Energy Commission to assess whether new nuclear power plants and advanced reactor technologies could help the state reach its goal of 100% renewable and zero-carbon electricity by 2045.

The law does not lift the state's 50-year-old moratorium on new nuclear plants — it orders a study. According to the American Nuclear Society's summary of the enacted text, the commission must complete the assessment by Jan. 1, 2028, and weigh cost, reliability, workforce benefits, emissions, the fuel cycle, public health and potential sites. The governor's office said the work will include public input.

For California households, the stakes run through the electric bill. The state is trying to replace fossil fuels while electricity demand grows, and the question the commission must now answer is whether new reactors would add affordable, steady power or add costs that ratepayers ultimately cover.

A Study Instead of a Repeal

When Assemblymember Lisa Calderon introduced AB 2647 in February, it proposed clarifying that the moratorium does not apply to advanced reactors. That language did not survive. ExchangeMonitor reported that an outright exemption faced an uphill battle because of concerns about nuclear waste, and that Calderon now describes the bill as a stepping stone toward reconsidering new plants.

Some early coverage described the laws as overturning the ban. That overstates what was signed. Any change to the moratorium would still require new legislation.

The Legislature adopted the moratorium in 1976. Under that law, new nuclear plants cannot be certified until the federal government approves a demonstrated method for permanently disposing of high-level radioactive waste. No permanent national repository exists, so the condition has never been met. The U.S. Supreme Court upheld California's law in a 1983 case brought by Pacific Gas and Electric.

"Fifty years ago, California made a choice based on the technologies and needs of that era," Calderon said in a statement quoted by the American Nuclear Society. "A.B. 2647 gives us the information to make a new choice."

Fusion Gets a Long-Range State Plan

Newsom also signed Senate Bill 925, by state Sen. Jerry McNerney. It requires the energy commission to produce a strategic plan for fusion energy by Dec. 31, 2029, including a regulatory framework and an analysis of how fusion at scale could support the state's long-term goals. The law also makes fusion component manufacturing eligible for a state program that streamlines environmental review for certain projects.

Fusion, which joins light atoms rather than splitting heavy ones, has not yet produced commercial electricity anywhere. SB 925 states that it does not create a technology set-aside, minimum or procurement mandate, so utilities are not required to buy fusion power. A state resolution supports siting a fusion pilot plant by the 2040s.

"Fusion energy has the potential to provide nearly limitless clean, safe, and reliable power," McNerney said.

Readers should note that much of the early reporting on these laws came from nuclear industry and professional outlets, including the American Nuclear Society and NucNet. NucNet also gave a different deadline, Jan. 1, 2027, for the assessment. The enacted bill text on the state's legislative information site is the authoritative source.

Diablo Canyon and the Cost Question

California once had four commercial nuclear plants. Rancho Seco near Sacramento and Humboldt Bay were shut down decades ago. The San Onofre plant near San Clemente was permanently retired in 2013 and is still being decommissioned at a projected cost of $4.5 billion. Diablo Canyon in San Luis Obispo County is the only one still running.

Diablo Canyon illustrates the tradeoffs the new study must weigh. It produces carbon-free power around the clock, but the legislative analysis of AB 2647 found that it operates at a nine-figure annual loss covered by PG&E ratepayers despite large public subsidies, as reported by The Center Square. Filings cited by the Alliance for Nuclear Responsibility put the cost of extending the plant through 2030 at roughly $11.8 billion.

Supporters argue that new designs could cut costs. "Our grid needs firm, clean power," Calderon said. San Luis Obispo County, which hosts Diablo Canyon, supported the bill, saying its analysis of costs, reliability and waste would inform future policy.

Opponents warn about risk and pressure from new demand. Haakon Williams, executive director of the Committee to Bridge the Gap, told The Center Square that the bill "sets in motion a process that could lead to the state opening its doors to one of the world's most dangerous toxic industries." He urged the commission to study waste and safety with rigor and neutrality, especially as data centers for artificial intelligence push electricity demand higher.

Next Steps Before Any Reactor Is Built

No new plant is being proposed under these laws, and no reactor could be licensed in California without both a change in state law and federal approval from the Nuclear Regulatory Commission. The next milestone is the energy commission's assessment, due by Jan. 1, 2028, which will be developed with public input. The fusion strategic plan follows by the end of 2029.

For ratepayers, the practical effect today is limited — these laws do not by themselves change electricity rates. The larger question is whether the commission concludes that nuclear power is worth its cost and waste burden for a state that wants clean, reliable electricity. Californians who want a voice can watch for public workshops announced by the energy commission once the assessment begins.

The bottom line: California has opened the door to a formal debate on new nuclear power, not to new reactors. The moratorium tied to waste disposal still stands, and the next real decision point is the 2028 assessment.

What Readers Want to Know

Did California lift its ban on new nuclear power plants?

No. AB 2647 orders a study of whether new nuclear plants could help meet climate goals. The 1976 moratorium remains in effect.

Why does California have a nuclear moratorium?

The 1976 law blocks new plants until the federal government approves a demonstrated method for permanently disposing of high-level radioactive waste. That condition has not been met.

When is the nuclear assessment due?

The enacted bill sets a deadline of Jan. 1, 2028, according to the American Nuclear Society's summary of the law.

What does the fusion law do?

SB 925 requires a state fusion energy strategic plan by Dec. 31, 2029, including a regulatory framework. It does not require utilities to buy fusion power.

Will these laws change my electric bill?

Not directly. They fund planning and analysis, not construction. Costs to ratepayers would depend on future decisions.

How many nuclear plants operate in California?

One. Pacific Gas and Electric's Diablo Canyon Power Plant in San Luis Obispo County is the state's only operating nuclear plant.