Talk:Small modular reactor

This page was a fairly short-term project. While many sources are available on Small Modular Reactors, many of them are outdated or obviously biased. There are new sources emerging all the time, but most of them are from small conferences and think-tanks, and not accessible for others to reference. I would appreciate any help that anyone can give to help increase the number of viable sources and information for this page. Help? BJMcNall (talk) 21:07, 7 July 2010 (UTC)

Remove Operation section
The entire "Operation" section seems unnecessary. It is a long section and basically describes the operation of various types of nuclear reactors, with no real information specific to small modular reactors. This kind of section would be appropriate for the Nuclear Reactor Technology article or the Nuclear Reactor Physics article. I believe that as it is, it does not add anything to the article as a whole. —Megiddo1013 18:03, 27 November 2010 (UTC)

This section would be better served by just having a link to the more general article on Nuclear reactors and their types.

I.E. - Jderek6208 (talk) 10:26, 19 August 2017 (UTC)An SMR is a scaled down version of Larger scale First and second generation power plants described in; https://en.wikipedia.org/wiki/Nuclear_power_plant. The heart of any Nuclear power station is it's nuclear island or Nuclear steam supply system (NSSS) See also; https://en.wikipedia.org/wiki/Nuclear_reactor. Reactor system safety is a factor of redundant reactor control rods systems typified by a set of primary reactor shutdown rods in the center of the core and a secondary set of reactor control rods. This control rods use delayed neutron fractions of the entire neutron population to limit the overall power of the core through out reactor life. For a more detailed explanation see; https://en.wikipedia.org/wiki/Nuclear_reactor_physics. And, https://energy.gov/sites/prod/files/2013/06/f2/h1019v2.pdf

I agree with Megiddo1013: most of the text in the "Operation" section is not specific to SMRs and should be replaced with a link to the Nuclear reactor article. TuomoS (talk) 15:19, 24 March 2018 (UTC)

Disadvantages and limitations of SMRs
This page as a whole reads like a funding request. Not being a nuclear scientist, there must be some information on limitations to this technology. No energy source is so clear of constraints. Geodaktari (talk) 17:05, 14 December 2013 (UTC)


 * Agreed, see "too promotional" section below... Johnfos (talk) 02:06, 3 January 2016 (UTC)

I agree that it's too one sided, so I've added a dedicated disadvantages/issues section, and added content - including with citation from widely-respected media source BBC News. Simonjon (talk) 11:31, 3 April 2016 (UTC)

As a former researcher I can certainly tell the bias of the previous detractors. I worked for fifteen years at the former Fast Flux Test Facility at Hanford, Washington USA. Which in reality was EBR number three. We derated FFTF from 400 MW thermal to 295 MW thermal to continue conducting limited research. Long story short in history section there is no mention of this facility or the Subsequently cancelled Porwer Reactor Inherently Safe Modular (PRISM) design by General Electric. Why, because politically Neither US DOE nor US NRC wanted to license and SMR. Heres the truth if you can Handle it.;

The FFTF while designed as a LMFBR was never allowed to be operated as a breeder reactor. It was successfully licensed and operated as a research reactor for over a decade. The operating crews received multiple awards and commendations for safe operation of the facility. When de-rated from 400 MWt to 295 MWt did not require it's Gas Expansion modules to be operated as an inherently safer reactor. As scram from 295 MWt resulted in an easy transformation from forced cooling to natural circulation cooling mode. In fact the disadvantage was that the liquid sodium required external electric resistance heating to keep from freezing solid. The general problem with all liquid metal or molten salt reactor facilities.

Additional advantages;

Electrical power requirements beyond two on station batteries is not required to keep a facility initially designed with natural circulation decay removal in mind in a safe shutdown mode. Two Naval submarine PWR's S5G and S8G an be operation at power with no coolant pumps in natural circulation modes of operation. — Preceding unsigned comment added by Jderek6208 (talk • contribs) 11:04, 19 August 2017 (UTC)

Needs a summary
Italic textVery hard to find out the history of actually constructed SMEs and which of the many current designs are ready for licencing or being constructed. - Rod57 (talk) 23:52, 8 April 2015 (UTC)

Too promotional: what about disadvantages, limitations, and the skeptics?
According to Mark Cooper, the failed “nuclear renaissance” of the 2000s did not live up to its promises and this experience should provide a rationale for healthy skepticism toward claims about new nuclear reactor technology:


 * "This skeptical approach should apply to the new darling technology of the nuclear industry, small modular reactors. The public is hearing exactly the same promises about standardization, modularization, learning curve cost reductions, improved safety, and fast construction schedules that were made—and broken—in regard to earlier reactor designs. These are assurances that drive the industry to skip proper research and development and careful pre-commercial demonstration. The early retirements in California, Florida, and elsewhere should lead to greater caution about nuclear power safety and economics, not less." -- Mark Cooper, "Nuclear aging: Not so graceful", 18 June 2013.

I've added a "missing information" tag which should help. -- Johnfos (talk) 02:06, 3 January 2016 (UTC)

I agree that it was too one sided, so I've added a dedicated disadvantages/issues section, and added content - including with citation from widely-respected media source BBC News. Simonjon (talk) 11:31, 3 April 2016 (UTC)

There is still no disadvantages on the english site! Has it been removed again. I think this site needs to be blocked by a supervisor. Some companys planning to make a lot of many with this. The German site of it has a good section "Bewertung" that contains a survey from some technical experts. Maybe that can be translated? 2 January 2022 — Preceding unsigned comment added by 85.212.128.248 (talk) 21:25, 2 January 2022 (UTC)

Merged in content from article Micro nuclear reactor
Article merged: See old talk-page here

Licensing
Submarine reactors presumably count as "small". Would a reactor, licensed for submarine use, also be licensed for use on land or are there separate regulatory regimes for marine and land use? Roberttherambler (talk) 18:50, 12 August 2016 (UTC)


 * My understanding is that a submarine reactors use highly enriched uranium and their design is a secret. So they can't be used in the civilian market.  However, the Russian Russian floating nuclear power station uses low enriched uranium could probably be licensed for land. Paul Studier (talk) 16:38, 13 August 2016 (UTC)


 * Thanks. Roberttherambler (talk) 22:18, 12 September 2016 (UTC)

This comment is extremely valid. See https://en.wikipedia.org/wiki/Category:Nuclear_propulsion

Naval Submarine reactors are not licensed in the same way as civilian power reactors. Although they get a rigorous review process, formerly a prototyping and testing phase. If licensing under the US NRC worked properly SMR's would in fact be a reality today. However, the US NRC should be more aptly entitle the US Nuclear Decommissioning Service. Since no new plants have been granted a license since 1975. The United States has lost the will to continue Nuclear Research into the the Twenty First century. And, such it is the opinion of this author no SMR or other reactor facility either can or will ever again be sited on US soil.

The USS Sam Rayburn SSBN 635 was converted from an operational submarine to the MTSD 635 https://en.wikipedia.org/wiki/USS_Sam_Rayburn_(SSBN-635) Sam Rayburn was decommissioned on 31 July 1989 and reclassified a moored training ship with hull number MTS-635.[3][4] Stricken from the Naval Vessel Register on 31 July 1989,[5] she arrived at the Naval Nuclear Prototype Training Unit at Goose Creek, South Carolina, in August 1989 after achieving initial criticality in her new role on 29 July 1989.[citation needed] Her modifications included special mooring arrangements, including Water Brake, a mechanism to absorb power generated by her main propulsion shaft.[citation needed] She is scheduled to operate as a moored training ship until 2020 while undergoing shipyard availabilities for repairs and alterations at five-year intervals.[citation needed]

Therefore, safe operation of submarine reactor designs as SMR's is not only possible but a defacto argument for their existence as viable electrical power generators. — Preceding unsigned comment added by Jderek6208 (talk • contribs) 11:34, 19 August 2017 (UTC)

History
At the end of the History section, it says "Smaller reactors would be easier to upgrade quickly, require a permanent workforce, and have better quality controls, just to name a few more advantages." Why would smaller reactors require a permanent workforce more than larger reactors do? Is this perhaps missing a "do not" before "require a permanent workforce" or perhaps "smaller" before "permanent"? —Salton Finneger (talk) 17:27, 21 June 2017 (UTC)

The history section is to small to fully address the point but here goes:

The premise of SMR's is to bridge the gaps in the two major problems with NRC licensing in the United States and presumably other nations. To operates nuclear reactor facility first and foremost the Nuclear Island/Heat Souce/Reactor Module has to be able to be built to rigid safety standards. The problem is now and the foreseeable future is that we have two many choices in designs. PWR's, BWR's, LMR's, HTGR's and molten salt reactors just to name the few on my mind. Imagine the similarity to automobiles. Diesel, Gasoline, Ethanol, Electric, Hybrid, plug-in hybrid. You get the point. No single group of people can agree on a standard automobile as safe. When there are so few physicists, and every journalist thinks they are the supreme expert on all things nuclear no one can agree on what really is the next best thing. Second there are issues with licensing any new sites. Siting by the sea, good maybe but not in the case of Fucushima, Japan. Geologically stable sites in the US. We came up with three for siting a Nuclear waste repository and even with a facility built and presumably licensing in Nevada, It will now never open. The NIMBYists kill any attempt to site any new facilities. So while SMR's are a fantastic idea. Nothing new will or can ever be built as a prototype to know if the idea is a good one or not. Hence, the best way to build test and license will continue to be Naval vessels. — Preceding unsigned comment added by Jderek6208 (talk • contribs) 11:52, 19 August 2017 (UTC)


 * I don't see anything in your note that addresses the question of whether "Smaller reactors . . . require a permanent workforce" is a correct statement of the advantages of a smaller reactor to a larger reactor, given that larger reactors certainly also have permanent workforces. —Salton Finneger (talk) 13:14, 21 September 2017 (UTC)

Rolls-Royce
Saw this on the Popular Mechanics site: Peaceray (talk) 20:07, 22 January 2020 (UTC)

PWR or LWR
Article currently lists the NuScale design as an LWR, see https://en.wikipedia.org/w/index.php?title=Small_modular_reactor&oldid=976514184#Reactor_designs but it's a PWR, a type of LWR. All other PWRs in the table are listed as PWRs, why is NuScale singled out for the less specific term? Andrewa (talk) 11:04, 4 September 2020 (UTC)


 * Changed to PWR. --TuomoS (talk) 12:10, 4 September 2020 (UTC)

And the types used in the table "Reactor designs" don't match those in Types or Technologies above. S C Cheese (talk) 20:15, 20 January 2022 (UTC)
 * In the table they are divided by type of cooling; in the section Types by type of nuclear reactions. The section Technologies is just a poor section. --Wickey (talk) 11:41, 8 February 2022 (UTC)

Style: large reactor or Large Reactor?
Needs to be consistent. Should it be capitalised? S C Cheese (talk) 20:08, 23 March 2022 (UTC)
 * If it refers to the size, it should be in lowercase; in official reactor names capitalised. In article titles, it may be capitalised, while it actually refers to the size. --Wickey (talk) 11:16, 24 March 2022 (UTC)

Slowpoke
"Until 2020, no truly modular SMRs had been built" I believe this statement to be false as the entire design of SMRs is so close as to be a copy of Canada's "Slowpoke Reactor" which have their own page on Wikipedia. Frend Jim (talk) 02:16, 5 July 2022 (UTC)


 * On Wikipedia, what you believe is known as original research, what matters is what reliable sources say about SMRs and the SLOWPOKE reactor. If you have reliable sources to cite, feel free to edit the statement accordingly. Rosbif73 (talk) 09:48, 5 July 2022 (UTC)

Proposed form
Since there currently are no SMR reactors, e.g. no volume production, I suggest this article to be written in the same pattern as the article on nuclear fusion, that an SMR is a *proposed* type of nuclear reactor. 176.10.159.46 (talk) 18:22, 30 August 2022 (UTC)
 * There is one working one, the Akademik Lomonosov. ---Lilach5 (לילך5) discuss 19:16, 30 August 2022 (UTC)


 * Indeed, an SMR is not just a reactor that is composed of modules, but a reactor that is produced in series. A single SMR does not make sense as it is as expensive to build as a conventional reactor and produces much less energy. Currently, there does not exists a single SMR which is produced in series (more than one or a few), and it will not be in the near future.--Wickey (talk) 10:24, 31 August 2022 (UTC)
 * Agreed, the article is written as if this is an established technology, not reflecting that, in reality, it is in the design- and prototype-phase at best. I have amended the article to reflect this. Fouriels (talk) 16:09, 31 October 2022 (UTC)

Clearer Definitions
I propose incorporating definitions of SMRs the intro paragraph based on those provided by Schaffrath et al. (2021), who differentiate between the common North American definition of maximum 300 MW output and the IAEA definition for small and medium reactors of up to 700 MW output.

Schaffrath, Andreas; Wielenberg, Andreas; Kilger, Robert; Seubert, Armin (2021-12-01). "SMRs — overview, international developments, safety features and the GRS simulation chain". Frontiers in Energy. 15 (4): 793–809. doi:10.1007/s11708-021-0751-2. ISSN 2095-1698>

EaglesEyes1 (talk) 04:07, 28 January 2023 (UTC)


 * Article is not about medium reactors. --Wickey (talk) 06:34, 28 January 2023 (UTC)

MH-1A was the first reactor on a barge, in 1967
MH-1A

See also Army Nuclear Power Program for antecedants of small, land-based reactors.

It would be relevant to teh present article to dwelve into why those early experiments did not prosper and multiply, and how the SMR currently being designed propose to overcome the same limitations. Noliscient (talk) 15:07, 10 April 2023 (UTC)

Economy
Section Economy looks quite optimistic if I read the last study https://doi.org/10.1016/j.energy.2023.128204 Jirka Dl (talk) 17:02, 29 October 2023 (UTC)

Database query error with the first section entitled "Safety"
A database query error has occurred. This may indicate a bug in the software. [41230317-9b97-47f1-9261-bb4559d878f8] 2023-12-04 16:45:24: Fatal exception of type "Wikimedia\Rdbms\DBQueryError".

Database error: To avoid creating high replication lag, this transaction was aborted because the write duration (14.113745689392) exceeded the 3 second limit. If you are changing many items at once, try doing multiple smaller operations instead. [84dd98ea-cd22-445e-95c0-afda38c6be57] 2023-12-04 17:38:03: Fatal exception of type "Wikimedia\Rdbms\DBTransactionSizeError"

This type of database error was recurrent and repeatable today with different attempts to edit the first of the two sections entitled "Safety".

Is this error due to the fact that there existed two sections that were both entitled "Safety"?

I renamed the second one as "Nuclear safety", but the error still subsists.

Anyway, the contents of both sections should be merged into one single section, or at contrary, clearly distinguished in two specific sections bearing different titles taking care to avoid any repetition. Shinkolobwe (talk) 17:42, 4 December 2023 (UTC)

NuSclae VOYGR vs NuScale Power Module™
I appreciate the information on the NuScale power NRC filing. It is true that NuScale does not have NRC approval for its 77 MWe Power Module for use in the VOYGR plant as of this date. However, NuScale does have a 50 MWe Power Module for use in the VOYGR plant licensed by NRC. Please make sure not to remove this approved SMR from the Wiki page. You are clearly not informed about the NuScale VOYGR system. The NuScale Power Module™ is NuScale's reactor. The NuScale Power Modules™ are the individual parts of what are used to assemble the NuScale VOYGR Plant. The NuScale Power Module was licensed by the NRC. The only thing NuScale has requested is an update to the Power Module for 77 MWe. Source: https://www.nrc.gov/reactors/new-reactors/smr/licensing-activities/current-licensing-reviews/nuscale-us460.html Source: https://www.nuscalepower.com/en/news/press-releases/2023/nuscale-enhances-case-for-small-modular-reactor-applications-in-major-industrial-processes Source: https://www.federalregister.gov/documents/2023/01/19/2023-00729/nuscale-small-modular-reactor-design-certification (talk) 15:07, 11 December 2023 (UTC) Ludviggy (talk)

"NuScale Power today announced updated evaluations for the technical feasibility and economics of producing hydrogen using heat and electricity from a NuScale Power Module™ (NPM) as a result of the recent announcement that an NPM can generate an additional 25 percent more power per module for a total of 250 MWt (or 77 MWe) per module." (Dec 2020) Source: https://www.businesswire.com/news/home/20201209005943/en/NuScale-Power-Releases-Updated-Evaluation-for-77-MWe-Module-Clean-Hydrogen-Production
 * I believe you are mistaken. For example the MIT Technology Review reports that the cofounder and chief technology officer at NuScale, Jose Reyes, said "The upgraded power rating requires some adjustments, but the module design is fundamentally the same. Still, it means that the company needed to resubmit updated plans to the NRC, which it did last month. It could take up to two years before the altered plans are approved by the agency and the company can move on to site approval, Reyes says." So the CEO says they need to wait for NRC approval before they can start site approval, which reads to me the same as a full re-approval. And if we look at a primary source, the NRC webpage for the approval, it is called a "Application for a Standard Design Approval" not an engineering upgrade of a standard design review, and it is in the "Current Licensing Reviews of New Reactors" section where it lists "reviews applications submitted by prospective licensees". again not for some engineering upgrade. IMO the 77 MWe version is not currently licensed. Rwendland (talk) 01:02, 18 December 2023 (UTC)


 * You're quote says everything, "...The upgraded power rating requires some adjustments, but the module design is fundamentally the same." The original NRC-licensed NuScale Power Module will remain the same product, only with greater output and allow for a plant size increase. All manufacturers will make changes to their NRC-approved plants as new needs arise. That doesn't mean they need to dump their current design and have an entirely new product licensed. The NRC will just review engineering changes and decide if the current design will safely handle the requested changes. If the NRC Review finds the original device is not suited for the requested changes, the manufacturer will either dump their original design and start over or just create a new generation product. That hasn't happened. Most will keep their NRC-licensed product, without changes, either way. Ludviggy (talk) Ludviggy (talk) 05:02, 18 December 2023 (UTC)

I quote some SEC and other official documents below, which I hope convinces you that the 6 * 77MWe VOYGR configuration is not licensed yet: I hope this is enough to convince you the 6 * 77MWe VOYGR design is not NRC licensed yet. Rwendland (talk) 22:46, 8 January 2024 (UTC)
 * The IPO Prospectus filed with SEC.gov, filed 1 July 2022, says "Summary of Risk Factors" ... "SDA [Standard Design Approval] application for the 77 MWe power module has not yet been submitted to the NRC, and its approval is not guaranteed". The body of the Prospectus expands this "Increasing the power that can be generated by our NPMs is a key part of our plan, and our higher- capacity, 77 MWe power module is subject to obtaining SDA from the NRC. The need to obtain that approval complicates our licensing process and could affect the planned deployment schedule for our first NPMs."
 * A bit further in the Prospectus NuScale says "We expect to submit an application to the NRC for our latest power enhanced design. If approved, the licensed output of our NPM will be raised from 50 MWe to 77 MWe. Approval of the design, which could come in 2024, would increase the cost-competitiveness of our NPM, and we consider obtaining such approval a critical milestone."
 * Prospectus Supplement No. 3, dated 14 November 2022, says "we may be obligated to refund to UAMPS [if] ... (3) the NRC does not issue SDA for the NuScale design within one year after the NRC’s published date for such approval after acceptance of the SDA application" so again clearly the 6 * 77MWe VOYGR design for UAMPS CFPP still needs NRC approval.
 * The NRC say the 6 * 77MWe SDA application review is currently 31% progressed today.
 * The Federal Register is the legal record of NRC licensing decisions, and it records here the licensing of the old 12 * 50MWe design is effective from 21 Feb 2023. I cannot find an entry for the approval of the 6 * 77MWe VOYGR design in the Federal Register (no surprise since the NRC say it is only 31% reviewed today).

First SMR Prototype Developed on Oregon State Campus
"NuScale is the first small modular reactor design reviewed by the NRC. NuScale is based on a small light water reactor developed at Oregon State University in the early 2000s. It consists of one or more NuScale power modules (hereafter referred to as power module(s))." SOURCE: https://www.federalregister.gov/documents/2023/01/19/2023-00729/nuscale-small-modular-reactor-design-certification Source: https://www.corvallisadvocate.com/2013/0228-osu-nuclear-testing-facility/ — Preceding unsigned comment added by Ludviggy (talk • contribs) 05:42, 18 December 2023 (UTC) (talk) 15:07, 11 December 2023 (UTC) Ludviggy (talk)

SMNR
Some sources use SMNR instead of SMR as the acronym. It means the same thing. These sources tend to be anti-nuclear-power and are in a minority to the point that https://www.google.com/search?q=SMNR%20nuclear asks me Did you mean: SMR nuclear?. IAEA uses the term SMR and doesn't even mention SMNR, but is that alternative worth mentioning? Andrewa (talk) 07:40, 19 April 2024 (UTC)

Union of Concerned Scientists. April 2024 article
Here is a more recent article: --Timeshifter (talk) 06:28, 8 May 2024 (UTC)
 * Five Things the “Nuclear Bros” Don’t Want You to Know About Small Modular Reactors. April 30, 2024. Union of Concerned Scientists. By Ed Lyman, Director, Nuclear Power Safety. The article is also found here:
 * https://www.commondreams.org/opinion/small-modular-reactors