The Nuclear Power Thread

[Astronuc]

Westinghouse’s ADOPT 6-percent enriched U fuel nears U.S. deployment
From Fri, Mar 17, 2023

Westinghouse Electric Company announced on March 14 that the Nuclear Regulatory Commission has approved the use of the company’s Advanced Doped Pellet Technology (ADOPT) fuel pellets in U.S. pressurized water reactors. That approval brings the company closer to loading lead test assemblies containing ADOPT accident tolerant fuel pellets in Unit 2 of Southern Nuclear’s Vogtle plant.

Lead test plans: Southern Nuclear announced in January 2022 that it had signed an agreement to load four lead test assemblies into Vogtle-2 in “the first planned installation of enrichments of uranium-235 greater than 5 weight percent in a domestic commercial reactor.” According to Westinghouse, the agreement calls for “licensing and manufacturing in 2023.”

High-assay low-enriched uranium (HALEU) includes uranium enriched to between 5 and 19.75 percent U-235, above the traditional 5 percent threshold for commercial reactors. The fuel pellets that are to be installed at Vogtle-2 contain uranium enriched to 6 percent—1 percent higher than the current license limit. According to Westinghouse, “Through its increased uranium density, ADOPT fuel . . . enables U.S. customers to improve fuel cycle economics and extend their operating cycles.”

The current maximum enrichment limit for commercial LWRs is 5.00%, and folks typically use a maximum of 4.90 or 4.95%, just to be sure the 5.00% limit is not exceeded.

 

[NTL2009]

Westinghouse’s ADOPT 6-percent enriched U fuel nears U.S. deployment
From Fri, Mar 17, 2023The current maximum enrichment limit for commercial LWRs is 5.00%, and folks typically use a maximum of 4.90 or 4.95%, just to be sure the 5.00% limit is not exceeded.

What is the reason for the enrichment limit? How much of any efficiency improvement is offset by the higher enrichment process?

Perhaps these can't be answered in such a way that a lay person could understand, in that case "because" will suffice! :)

 

[Astronuc]

What is the reason for the enrichment limit? How much of any efficiency improvement is offset by the higher enrichment process?

Facilities that make enriched fuel and facilities that use enriched fuel must perform criticality analysis on their processes to ensure under normal and off-normal operation, the system will not experience a criticality accident, which could expose workers to neutron and gamma radiation. By imposing an enrichment limit, the analysis is bounding, up to that enrichment. As the enrichment increases, it takes less material (uranium) to reach criticality under the various special circumstances, and usually that has to do with aqueous solutions of uranium compounds. Most of the time, the systems are processing enriched uranium oxides, and there are strict limits on much material can be stored in close proximity to other material, and various hypothetical situations like a severe rain storm that floods the storage area, or manufacturing area, or if there is a fire, what would happen if water was sprayed on the fire.

The higher enrichment allow fuel to reach a higher burnup, so increasing enrichment from 5% to 6%, for example, means roughly a 20% increase in burnup capability, or using fewer assemblies in a batch/reload.

Research reactors have traditionally used highly enriched material (~93%) dispersed in aluminum or Zr-alloy. However, over the past couple of decades, there has been an effort to eliminate the highly enriched fuel with so-called 'high-assay, low-enriched U' fuel, or HALEU, with a 20% limit. Some advanced reactor and fuel designs will be using HALEU - probably up to 19.75% enrichment.

 

[gmax137]

Just to add to @Astronuc 's reply, "higher burnup" means the plant is replacing fewer fuel assemblies at each refueling. This may save them operating costs. There is a delicate balance between the enrichment level (which costs money) and the number of fresh fuel assemblies (which also costs money, above and beyond the cost of the uranium itself). The power companies that operate the plants and the fuel vendors who supply the fuel have teams of nuclear engineers who work constantly to optimize the design of the upcoming batch of fuel.

Also, over the years the fuel cladding designs have improved such that the fuel can be run longer (higher burnup) without cladding corrosion or other problems cropping up. So back in the day, there was no reason to use 5% enrichment since the fuel would be removed before the higher enrichment would provide any benefit. Modern cladding materials allow the core design to take advantage of higher enrichment.

The 5% limit is, as far as I know, an arbitrary value selected in the past.

This all was not really my area, so if I have led the OP astray here, I hope @Astronuc or other PF'ers will jump in and correct my woolly thoughts.

 

[Astronuc]

Also, over the years the fuel cladding designs have improved such that the fuel can be run longer (higher burnup) without cladding corrosion or other problems cropping up. So back in the day, there was no reason to use 5% enrichment since the fuel would be removed before the higher enrichment would provide any benefit. Modern cladding materials allow the core design to take advantage of higher enrichment.

I've worked with some utilities who have been using up to 4.95% enriched fuel since more than 20 years ago. Their plants did a full uprate from the original ~3450 MWt to 3685 MWt. The fresh fuel batch sizes were about 84,85, or maybe 88,89 depending, and cycle lengths were up around 530 EFPD give or take (for 18 month cycles). Lower power density PWR plants (14x14, 15x15, and 16x16 fuel) have opted to run 24-month cycles out to 660 to 700+ EFPD, and most BWRs have opted for 24 month cycles. BWR fuel uses variable and zoned enrichment in the fuel assembly lattice, and I have seen 4.90 enriched fuel used in the highly enriched fuel rods.

 

[Astronuc]

Finnish EPR enters regular electricity production
https://world-nuclear-news.org/Articles/Finnish-EPR-enters-regular-electricity-production

Test production has been completed at the Olkiluoto 3 (OL3) EPR in Finland and the plant has now started regular electricity production, operator Teollisuuden Voima Oyj (TVO) has announced. TVO said the reactor will soon be declared to be in commercial operation.

OL3 attained first criticality on 21 December 2021 and was connected to the grid on 12 March 2022. The EPR, a 1600 MWe pressurised water reactor, then entered a phase of test production during which some 3300 tests were conducted and more than 9000 test reports collated.

The completion of test production was initially delayed after material that had detached from the steam guide plates was found in the turbine's steam reheater in May, which required inspection and repair work. Later, in October, damage was discovered in the internals of the feedwater pumps located in the plant's turbine island during maintenance and inspection work.

The plant was operated at full capacity for the first time in late-September last year [2022].

TVO announced on 16 April that test production at the plant had been completed and regular electricity production has now started.

OL3 will produce about 15% of Finland's total electricity consumption, while the Olkiluoto plant as a whole will generate about 30% of the country's electricity.

In the US, "Vogtle unit 3 began supplying its first electricity to the grid on 1 April, Georgia Power announced. The AP1000 reactor - the first new reactor to start up in the USA since 2016 - is scheduled to enter commercial operation by mid-year."
https://world-nuclear-news.org/Articles/Grid-connection-for-Vogtle-unit-3

Meanhile, in Germany, the last 3 remaining nuclear plants are shutdown! The smoking steaming towers of Isar II, Emsland and Neckarwestheim II reactors were to shut forever by midnight on Saturday as Berlin enacts its plan for fully-renewable electricity generation by 2035.
https://www.reuters.com/world/europ...ermany-closes-last-nuclear-plants-2023-04-14/

Isar-II, Emsland and Neckarwestheim-II are three Konvoi plants, which use 18x18 fuel lattice.

 

[bhobba]

Do you know if this is real?
https://www.tokamakenergy.co.uk/2023/04/12/first-look-at-tokamak-energy-fusion-power-plant/

If so it will be transformational.

Thanks
Bill

 

[Astronuc]

Do you know if this is real?

It's probably as real as any other fusion program. They apparently have some partnerships with ORNL, PPPL, UKAEA and others. One would have to review the CV of the principals to see if they have any affiliation Culham or other fusion program.

https://www.tokamakenergy.co.uk/202...rototype-to-be-built-at-ukaeas-culham-campus/

So apparently they have some connection with the Culham Centre.

 

[Astronuc]

Finnish utility Teollisuuden Voima Oyj (TVO) has issued an acceptance certificate to the Areva-Siemens consortium for the Olkiluoto 3 (OL3) EPR, which began regular electricity production on 16 April. It said the 1600 MWe reactor is scheduled to enter commercial operation on 1 May.

https://world-nuclear-news.org/Articles/TVO-accepts-Olkiluoto-EPR-ahead-of-commercial-oper

The Areva-Siemens consortium constructed the OL3 plant under a fixed-price turnkey contract. They have joint liability for the contractual obligations until the end of the guarantee period of the unit. Construction of Olkiluoto 3 began in 2005, with completion of the reactor originally scheduled for 2009, but the project has had various delays and setbacks.

OL3 attained first criticality on 21 December 2021 and was connected to the grid on 12 March 2022. The EPR, a 1600 MWe pressurised water reactor, then entered a phase of test production during which some 3300 tests were conducted and more than 9000 test reports collated.

"The last phases of trial operation have been analysed and the project has been completed," TVO declared.

"The plant unit ordered with a turnkey contract has been accepted as received today," TVO said. "The final acceptance of the plant unit takes place after the end of the two-year warranty period. Even after that, the plant supplier's warranty responsibilities continue in certain parts for a maximum of eight years."

TVO said OL3 will enter commercial operation on 1 May, "which means, among other things, that the capitalisation of project costs will be stopped and the recording of depreciation will begin".

 

[Astronuc]

Once upon a time in the desert . . .

The KIWI/NERVA reactors were epithermal based on a graphite core, which contained highly enriched U dispersed in the graphite matrix. The KIWI test times were many minutes, not the hours or days needed for a long mission. A beryllium reflector would be problematic from the standpoint of high energy gamma rays (E > 1.64 MeV) from certain nuclides in the core, and boron (B-10) would be problematic with respect to the (n,α) reaction, in which B-10 disintegrates (fissions). KIWI's maximum power was 1 GWt; the last test (in 1964), a restart of KIWI-8, lasted 2.5 minutes with a calculated 750 seconds. The theoretical I^sp = 834 seconds in vacuo.

https://en.wikipedia.org/wiki/Project_Rover
https://en.wikipedia.org/wiki/NERVA (Nuclear Engine for Rocket Vehicle Applications)

 

[Astronuc]

Useful information in the reports here
Working Party on International Nuclear Data Evaluation Co-operation (WPEC)
https://www.oecd-nea.org/download/wpec/A good paper on "A Rate Theory Model of Radiation-Induced Swelling in an Austenitic Stainless Steel"
https://www.mdpi.com/2673-4362/2/4/34

I've worked with two of the authors.

 

[artis]

A rather interesting discussion about the generalities of the topic and the already here mentioned Finland's new reactor
The problem that I see in the faces of the participants of this otherwise interesting discussion is that each is holding on to their beliefs, which as true as they may be, is not in itself a fully rational position given that each approach to energy has it's flaws and drawbacks which at times can only be corrected by the use of the other methods, the very methods each participant seems to downgrade.

 

[Astronuc]

Useful information on LWR/VVER water chemistry issues

RADIATION PROTECTION ASPECTS OF PRIMARY WATER CHEMISTRY AND SOURCE-TERM
MANAGEMENT (April 2014)
https://one.oecd.org/document/NEA/CRPPH/R(2014)2/En/pdf

 

[Astronuc]

Companies say they're closing in on nuclear fusion as an energy source. Will it work?​

Fusion power could change the world. If it worked, it would grant humanity eye-watering quantities of electricity without producing any greenhouse gas emissions. The warming of the planet would slow, environmental pollution would drop, and energy would be cheaper than ever.

"We can generate electricity, theoretically, at much lower costs than we currently generate it now," he says. "And do it without fossil fuels."

Lofty promises. Obtaining deuterium fuel is expensive, and tritium even more so. The capital cost of a power plant will also be significant, and disposal of activated structural materials will be a substantial cost.

 

[gmax137]

Thanks @Astronuc that was an interesting read.

"We can generate electricity, theoretically, at much lower costs than we currently generate it now,"

I wish them well, but there's a sticky word in there...

 

[Astronuc]

Not sure about starting a thread on current R&D in Nuclear Thermal Propulsion (NTR) until I do some more homework, but there are various paper studies and some experimental work.

Thermal, Fluid and Neutronic Analysis of an LEU Nuclear Thermal Propulsion Core
https://ntrs.nasa.gov/citations/20190029258

Multiphysics Simulation of the NASA SIRIUS-CAL Fuel Experiment in the Transient Test Reactor Using Griffin​

https://www.mdpi.com/1996-1073/15/17/6181?type=check_update&version=2

 

[Astronuc]

US NRC - Increased Enrichment
https://www.nrc.gov/reactors/power/atf/technologies/enrichment.html

In the near term, 5 to 8% enrichment may be found in some fuel designs, and more likely 5 to 6%. I just reviewed a specification for 5 to 8%. Previously, I'd reviewed a standard specification for 5 to 20% (for HALEU).

https://world-nuclear-news.org/Articles/Vogtle-unit-to-test-6-enriched-fuel

Uranium is enriched while in the form of UF₆, so the enrichment facilities and containers must be designed to accommodate the greatest enrichment. This involves criticality evaluations and plant designs that exclude moderating materials from the enriched material. Equipment must be separated to prevent critical configurations.

Subsequent forms of U, as in UO₂ or other compound or alloy, are subject to the same considerations. One also has to address transportation, including hypotheticals - e.g., truck carrying assemblies crosses a river or body of water and the bridge fails or the trailer or load goes off the bridge into the water. Can the containers maintain a subcritical configuration?

 

[Astronuc]

Teollisuuden Voima Oyj (TVO), Olkiluoto NPP
https://www.world-nuclear-news.org/Articles/TVO-eyes-extended,-expanded-use-of-Olkiluoto-units

BWR Units 1 and 2 - which were first connected to the grid in September 1978 and February 1980, respectively - currently meet 15% of Finland's electricity demand. Olkiluoto-3 (Unit 3) a 1600 MWe unit provides another 15% of the electricity to Finland.

The investments, it said, have also enabled power uprates of the units from their original capacities of 660 MWe (net) to the current 890 MWe.

In addition to the operating licence extension, TVO said it has also looked at opportunities to further uprate the power of the units. An uprating of 80 MWe is being investigated for both units, increasing power levels from 890 MWe to about 970 MWe. This would mean an annual production increase of 1.2 TWh, TVO noted.

Many LWRs were designed with a margin of 20%, and better/refined methods and calculations have enabled uprates of up to 20% at many plants in the US. Some retrofitting was needed for the increased capacity. Margins to safety limits are preserved/maintained.

https://www.tvo.fi/en/index/news/pressreleasesstockexchangereleases/2024/4718828.html

This is the highest production volume ever in the history of Olkiluoto. It was naturally due to the fact that instead of two plant units, there are now three units operating in regular electricity production.

After the start of regular production at Olkiluoto 3, the unit was only out of production for under four days.

The most recent of the plant units, Olkiluoto 3, already produced 1.9 TWh of electricity in 2022 when it was still undergoing the test production phase. Actual regular electricity production was started at OL3 in the early hours of the morning on 16 April 2023.

Despite the year 2023 not being anywhere close to a full production year for 2023, the newest plant unit still produced by far the most electricity of all three units in Olkiluoto. OL3 produced 10.37 TWh of electricity to the national grid last year. That is 42% of the whole production volume in Olkiluoto.

 

[Astronuc]

GE Hitachi (GEH) offers the BWRX-300 SMR based on BWR technology.
https://www.nrc.gov/reactors/new-re...ties/pre-application-activities/bwrx-300.html

Note the GE Vernova identity.
https://www.gevernova.com/nuclear/carbon-free-power/bwrx-300-small-modular-reactor
https://www.ge.com/news/press-relea...or-achieves-pre-licensing-milestone-in-canada

https://aris.iaea.org/PDF/BWRX-300_2020.pdf

On December 1, 2021 Ontario Power Generation (OPG) selected the BWRX-300 SMR for use at the Darlington Nuclear Generating Station. In October 2022, OPG applied for a construction license for the reactor. The company expects to make a construction decision by the end of 2024 and has set a preliminary target date of 2028 for plant operations.

On July 7, 2023 Ontario Power Generation chose three additional BWRX-300 SMR for construction at the Darlington New Nuclear Project in Ontario, Canada, joining the first already planned.

Ref: https://en.wikipedia.org/wiki/BWRX-300. (insufficient technical information)

We'll see.https://neutronbytes.com/2023/03/26/tva-opg-synthos-green-team-up-for-bwrx300-smr/
Page shows BWRX-300 with 870 MWt with 270 MWe (perhaps net, as opposed to 30 MWe gross?) with a coolant outlet temp of 278°C.

The core has 240 fuel assemblies (possibly GNF2 or GNF3 variants); the average assembly power is then ~3.63 MWt. Some assemblies must operate a higher power, since the peripheral assemblies operate at less than core average power, as neutron flux decreases toward the core periphery. All but 12 assemblies have a control rod (BWR controls sit among 4 assemblies usually) associated with them.

The system uses natural convection in the core rather than pumped flow. The coolant is boiled in the core, steam rises, passes to a turbine, where it eventually condenses, and the water is returned to the downcomer in the reactor vessel.

More generally
https://www.world-nuclear.org/infor...er-reactors/small-nuclear-power-reactors.aspx

Breakthrough Institute - their opinions (or rather that of Matthew Wald)
https://thebreakthrough.org/issues/energy/meet-ten-of-the-next-five-successful-advanced-reactors

Note that NuScale laid off about 40% of staff, and X-Energy has quietly reduced staff.

In a seminar yesterday, the presenter mentioned about 108 SMR concepts; certainly, most will not succeed - maybe 5 to 10 types. US, Canada, UK, France, Korea, Japan, Russia, China and India, all with active nuclear power programs, have multiple parties considering SMRs - lots of competition - few winners.
https://aris.iaea.org/sites/overview.html
https://aris.iaea.org/sites/Publications.html

 

[Astronuc]

Back in 2022 - U.S. funds projects to explore nuclear waste reprocessing​

https://www.reuters.com/business/en...xplore-nuclear-waste-reprocessing-2022-10-21/

WASHINGTON, Oct 21 (Reuters) - The Biden administration on Friday said it is funding projects to recycle nuclear waste from power plants including through reprocessing, a technology that has not been practiced in the United States for decades because of concerns about costs and proliferation.

The Advanced Research Projects Agency-Energy, or ARPA-E, aims to develop a dozen projects to recycle the waste, also known as spent nuclear fuel, with $38 million in funding. A Department of Energy agency, ARPA-E supports research into high-risk but potentially transformational projects.

That is a low level of funding.

November 22, 2022
https://www.anl.gov/article/argonne...velop-technologies-for-recycling-nuclear-fuel

The larger project was awarded $4.9 million. It focuses on increasing the efficiency and, therefore, the economics of nuclear fuel recycling processes. Argonne, Oklo Inc. and Deep Isolation are working to improve a process that converts UNF oxide fuel to a metal that can then be processed to provide usable materials for advanced reactor fuel. The project will combine improvements in stable, next-generation anode materials and sensors used to control the process to maximize the amount of material that can ultimately be recovered.

Krista Hawthorne, the pyroprocess engineering section manager in Argonne’s Chemical and Fuel Cycle Technologies division, leads the effort.

“Improving the efficiency of fuel recycling processes will help recover and recycle valuable resource materials remaining in used nuclear fuel,” said Hawthorne. “Our partnerships with ARPA-E and industry are incredibly important to closing remaining technology gaps.”

The second project was awarded $1.52 million. With this project, Argonne researchers will develop, produce and test more efficient industrial chemical processing equipment to reprocess UNF. The project lead is Argonne radiochemist Anna Servis.

Apparently funding is continuing in the "Consolidated Appropriations Act, 2024’’ - DIVISION D—ENERGY AND WATER DEVELOPMENT AND RELATED AGENCIES APPROPRIATIONS ACT, 2024
https://docs.house.gov/billsthisweek/20240304/HMS31169.PDF
It's just a matter of finding/identifying the specific line that refers to the allocation or renewal of previous authorized funds.


I listened to a presentation the other day given by some ANSTO scientists, and one topic was waste isolation. Synroc was mentioned, so that's still on the table. I looked into that as part of a course 40+ years ago.

 

[Astronuc]

COVERT TOWNSHIP — Thanks to federal funding announced Wednesday, the Palisades nuclear facility in Michigan is poised to be the first shuttered plant to resume nuclear energy generation. Officials say Palisades, and the energy it produces, will be key to meeting goals for lowering carbon emissions.

The company that owns Palisades Energy LLC, Holtec International, will receive up to a $1.52 billion conditional loan from the U.S. Department of Energy. The funding will allow the 800-megawatt-capacity plant to resume energy production, company officials and U.S. Secretary of Energy Jennifer Granholm said Wednesday morning.

https://www.freep.com/story/news/lo...clear-plant-nuclear-power-energy/73115767007/

Palisades is a unique PWR that uses cruciform control rods and consequently a unique fuel design to accommodate the control rods which are function between fuel assemblies rather than in particular fuel assemblies.

 

[Astronuc]

From ASTM E531.

Neutron Spectrum Calculations – neutron spectrum calculations involve two tasks: (1) determination of the neutron source distribution in the reactor, and (2) transport of the neutron source through the reactor environment to determine the neutron fluence rate distribution at the surveillance location of interest. The specific computational method applied must be validated by comparing results with measurements made on one or more representative benchmark experiments.

 

[gmax137]

Palisades is a unique PWR that uses cruciform control rods and consequently a unique fuel design to accommodate the control rods which are function between fuel assemblies rather than in particular fuel assemblies

Palisades was the first commercial NSSS provided by Combustion Engineering. The CE Nuclear brain trust in those days included a number of Argonne labs luminaries. So I always saw their fingerprints in the almost BWR like aspects of the reactor design.

In any event, it will be interesting to see how the re-licensing process goes. I'm thinking a couple of well-heeled intervenors could really throw a wrench into the works.

 

[Astronuc]

The CE Nuclear brain trust in those days included a number of Argonne labs luminaries.

I met some of those folks during projects with utilities and CE.

In Europe, more than 70 nuclear reactors have already closed down and it is estimated that dozens more will follow in the coming years. It therefore won't be long before they fall due for dismantling. Recycling and re-using the maximum quantity of materials makes it possible to reduce the ecological footprint of dismantling. And that is what this project is all about: a desire to create a circular economy in dismantling.

https://www.sckcen.be/en/news/nuclear-melting-furnace-also-receives-green-light-europe-0

Not what I expect when I read the title.

 

[Vanadium 50]

included a number of Argonne labs luminaries.

Including Marius Stan, who plated Bogdan in Breaking Bad? Can't get more famous than that.

 

[gmax137]

No, the guys I'm talking about were much earlier. Walter Zinn, Harold Lichtenberger. That era.

 

[Astronuc]

In Wyoming, Bill Gates moves ahead with nuclear project aimed at revolutionizing power generation
https://apnews.com/article/bill-gat...-electricity-23176f33200b22b9ede7f4ccf4f2ec3b

Bill Gates and his energy company are starting construction at their Wyoming site for a next-generation nuclear power plant he believes will “revolutionize” how power is generated.

Gates was in the tiny community of Kemmerer Monday to break ground on the project. The co-founder of Microsoft is chairman of TerraPower. The company applied to the Nuclear Regulatory Commission in March for a construction permit for an advanced nuclear reactor that uses sodium, not water, for cooling. If approved, it would operate as a commercial nuclear power plant.

The site is adjacent to PacifiCorp’s Naughton Power Plant, which will stop burning coal in 2026 and natural gas a decade later, the utility said. Nuclear reactors operate without emitting planet-warming greenhouse gases. PacifiCorp plans to get carbon-free power from the reactor and says it is weighing how much nuclear to include in its long-range planning.

 

[Astronuc]

Separately, apparently the NRC's SDA of NuScale's SMR is ongoing, or parts of it.
Ref: https://www.federalregister.gov/documents/2023/03/17/2023-05457/nuscale-power-llc
https://www.nrc.gov/reactors/new-re...on-activities/idaho-national-labs-preapp.html

There is still interest in the concept.
https://news.yahoo.com/finance/news/why-nuscale-power-stock-ripped-203012874.html

 

[gmax137]

In Wyoming ... Kemmerer...

In case anyone was wondering, Kemmerer is in western Wyoming, about 50 miles northeast of Salt Lake.

 

[Astronuc]

AstroVinci™ Microreactor​

https://www.westinghousenuclear.com/energy-systems/astrovinci-microreactor/

The AstroVinci™ microreactor leverages the features of the eVinci™ heat pipe reactor including a matrixed core design, industry leading heat pipe design and manufacturing, and integrated controls and power conversion. The AstroVinci microreactor design can support various mission types with power outputs ranging from 10kWe to 100kWe, easily addressing the power needs of on-orbit or lunar surface applications. The core is designed to run for up to 10 years to support extended mission durations. The simple design of the AstroVinci microreactor fission power system allows for the reduction of failure points, simple operation and increased reliability for the harsh environment of space.

https://info.westinghousenuclear.com/space-symposium