Tag Archives: Nuclear Regulatory Commission

The NRC will allow the Diablo Canyon 1 & 2 nuclear power plants to continue operating while considering their belated license renewal applications

Peter Lobner

This is good news for all Californians and California businesses that depend on the State’s rather fragile electrical grid as their primary source of electric power! 

On 2 March 2023, the U.S. Nuclear Regulatory Commission (NRC) granted an exemption to Pacific Gas & Electric Co. (PG&E) that would allow the Diablo Canyon 1 & 2 nuclear power plants to continue operating while the NRC considers its license renewal application. The NRC press release stated:

“The exemption granted today will allow those licenses to remain in effect provided PG&E submits a sufficient license renewal application for the reactors by Dec. 31, 2023. The NRC will continue its normal inspection and oversight of the facility throughout the review to ensure continued safe operation. If granted, the license renewal would authorize continued operation for up to 20 years.”

Diablo Canyon Nuclear Power Plant. 
Source: Pacific Gas & Electric Company

You can read the full NRC press release here: https://www.nrc.gov/cdn/doc-collection-news/2023/23-015.pdf

You can track the status of the Diablo Canyon license renewal process on the Nuclear Regulatory Commission website here: https://www.nrc.gov/reactors/operating/licensing/renewal/applications/diablo-canyon.html

You may recall that, in 2016, many environmental groups and state legislators claimed victory in getting the commitment from PG&E to close the Diablo Canyon nuclear power plant early.  Here’s just one example of that sentiment at the time:

“In a major victory for environmentalists, California is going nuclear-free, ending atomic energy’s more than half-century history in the state. On Tuesday, one of the state’s largest utilities agreed to a proposal endorsed by environmental groups and labor unions to shutter California’s last operating nuclear power plant, Diablo Canyon, by 2025.” (Source: Democracy Now, 22 June 2016).

In my 2016 post, “The Nuclear Renaissance is Over in the U.S.,” I noted: 

“On 21 June 2016, PGE issued a press release announcing that they will withdraw their application to the NRC for a 20-year license extension for the Diablo Canyon 1 & 2 nuclear power plants and will close these plants by 2025 when their current operating licenses expire.  PGE will walk away from about 41 GW-years of carbon-free electric power generation.”

Almost seven years ago, it was quite apparent to many that the early closure of Diablo Canyon would not be good for California or the environment.  It took that long for the state government to understand the situation and support the current effort to get the Diablo Canyon operating licenses extended.  Better late than never.  However, in their shortsighted view, the state government seems to be supporting a license extension only through 2030. If the legislators have their way, California will reclaim only a small portion of the carbon-free electric power generation that would be available from the 20 year operating license extensions that the NRC may grant.

I’d like see the California legislature and the associated complex web of state agencies that have a stake in this matter unanimously acknowledge that nuclear power is an important contributor toward energy de-carbonization.  In addition, I’d like to see that same group acknowledge that nuclear power plants are important for delivering reliable 24/7 generating capacity to the CALISO grid, and thereby helping maintain stability on a grid with a large fraction of variable-output, renewable generators.  If those factors are important to California’s government, then perhaps there is a future for nuclear power in the state, including the new generation of small, modular reactors (SMRs). California state support for nuclear power generation would open many exciting options for modernizing and decarbonizing electric power generation, transmission and distribution throughout the state, while ensuring that reliable electric power is available to all residents and business, many of which are seeking to decarbonize their activities by replacing their fossil fuel use with electricity that is available as needed, 24/7.

You can call that my California dream.

For more information:

NuScale Submits First Ever Design Certification Application (DCA) for a Small Modular Reactor (SMR)

Peter Lobner

For all the talk about SMRs over the past two decades or more, there have been no SMR license applications submitted to the U.S. Nuclear Regulatory Commission (NRC) until now. On 31 December 2016, NuScale Power, Portland, OR made the first ever request to the NRC to initiate a licensing review of an SMR. On 12 January 2017, NuScale made the formal submittal to NRC of all the required DCA documents for an SMR power plant comprised of 12 individual NuScale Power ModulesTM.

An NPM is a small pressurized water reactor (PWR) with an integrated primary system and many passive features for normal modes of operation and for safe shutdown in response to abnormal or accident conditions. NuScale claims that the passive safety features enable shutdown and self-cooling with no operator action, no AC or DC power, and no external water.

You’ll find a good 2013 overview of the NuScale Power ModuleTM on the IAEA’s (International Atomic Energy Agency’s) ARIS (Advanced Reactor Information System) website at the following link:


More information is available on the NuScale Power website at the following link:


The basic, factory-manufactured NPM is rated at 160 MWt, which could deliver about 45 MWe. A power plant with 12 NPMs would have a combined output of 1,920 MWt and about 540 MWe. A single NPM is shown below.

NuScale moduleSource: NuScale Power

NuScale Power anticipates a 42-month licensing process as outlined in the following chart. If this schedule can be achieved, then the NRC could issue a Design Certification (DC) as soon as July 2020. At that time, the standard design of a modular NuScale power plant with up to 12 NPMs will have NRC approval independent of an application to construct or operate a specific plant. A design certification is valid for 15 years from the date of issuance and can be renewed.

NuScale licensing scheduleSource: NuScale Power

A license application for an actual plant will focus on site-specific issues and should not need to re-open issues already covered in the NRC’s DC review. This greatly de-risks construction of a new nuclear power plant based on the NPM standard design approved in the DC. NuScale forecasts that the first NPM could go into operation as soon as 2024.

Fukushima Daiichi Current Status and Lessons Learned

Peter Lobner

The International Atomic Energy Agency (IAEA) presents a great volume of information related to the 12 March 2011 Fukushima Daiichi accident and the current status of planning and recovery actions on their website at the following link:


From this web page, you can navigate to many resources, including: Fukushima Daiichi Status Updates, 6 September 2013 – Present. Here is the direct link to the status updates:


The IAEA’s voluminous 2015 report, The Fukushima Daiichi Accident, consists of the Report by the IAEA Director General and five technical volumes. The IAEA states that this report is the result of an extensive international collaborative effort involving five working groups with about 180 experts from 42 Member States with and without nuclear power programs and several international bodies. It provides a description of the accident and its causes, evolution and consequences based on the evaluation of data and information from a large number of sources.

IAEA Fukushima  Source: IAEA

You can download all or part of this report and its technical annexes at the following link to the IAEA website:


There have been many reports on the Fukushima Daiichi accident and lessons learned. A few of the more recent notable documents are identified briefly below along with the web links from which you can download these documents.

Japan’s Nuclear Regulatory Authority (NRA):

A summary of the NRA’s perspective on Fukushima accident and lessons learned is the subject of the March 2014 presentation, “Lessons Learned from the Fukushima Dai-ichi Accident and Responses in New Regulatory Requirements.” You can download this presentation at the following link:


 National Academy of Sciences:

The U.S. Congress asked the National Academy of Sciences to conduct a technical study on lessons learned from the Fukushima Daiichi accident for improving safety and security of commercial nuclear power plants in the U.S. This study was carried out in two phases. The Phase 1 report, Lessons Learned from the Fukushima Nuclear Accident for Improving Safety of U.S. Nuclear Plants, was issued in 2014, and focused on the causes of the Fukushima Daiichi accident and safety-related lessons learned for improving nuclear plant systems, operations, and regulations exclusive of spent fuel storage.

NAP Fukushima Phase 1  Source: NAP

If you have a MyNAP account, you can download the Phase 1 report at the following link to the National Academies Press website:


The Phase 2 report, Lessons Learned from the Fukushima Accident for Improving Safety and Security of U.S. Nuclear Plants: Phase 2, recently issued in 2016, focuses on three issues: (1) lessons learned from the accident for nuclear plant security, (2) lessons learned for spent fuel storage, and (3) reevaluation of conclusions from previous Academies studies on spent fuel storage.

NAP Fukushima Phase 2  Source: NAP

If you have a MyNAP account, you can download the Phase 2 report at the following link:


U.S. Nuclear Regulatory Commission (NRC):

A summary of the U.S. NRC’s response to the Fukushima accident is contained in the May 2014 presentation, “NRC Update, Fukushima Lessons Learned.” You can download this presentation at the following link: