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For those interested in magnetic-confinement-based fusion:
http://www-fusion-magnetique.cea.fr/gb/accueil/index.htm
http://www-fusion-magnetique.cea.fr/gb/accueil/index.htm
Astronuc said:For those interested in magnetic-confinement-based fusion:
http://www-fusion-magnetique.cea.fr/gb/accueil/index.htm
Astronuc said:A useful reference - https://flowcharts.llnl.gov/
Yes, that is about right.Imager said:Are we really just 33% efficient?
I thought that sounded confusing, so Google gives me the full quote:Imager said:The flowchart shows 67.5 Rejected Energy. My google search says, "Rejected energy is part of the energy of a fuel — such as gas or petrol — that could be used for a purposeful activity, like making electricity or transport. However, because of the technologies that we currently use to consume fuels, a lot of it gets tossed out by turning it into heat in the environment...".
Are we really just 33% efficient?
Rejected energy is energy that isn't used for a purposeful activity, but that doesn't necessarily mean it "could be". Some can, some can't. So, some gets rejected because it is impossible to recover/re-use and some gets rejected because it is difficult to recover/re-use.Rejected energy is part of the energy of a fuel – such as gas or petrol – that could be used for a purposeful activity, like making electricity or transport. However, because of the technologies that we currently use to consume fuels a lot of it gets tossed out by turning it into heat in the environment, which is totally useless. For a coal fired power station, for instance, about 2/3 of the energy released when the coal is burnt is discarded as heat in the environment. This reject energy sometimes appears as clouds of vapour coming off a power-station’s cooling towers, such as the well-known ones at Didcot in England.
That's right. I once live in Västerås Sweden. Heat rejected in the power plant's condenser (plus some steam extracted at the reheat stage) warmed water from the lake. The warmed water provided heat and hot water for the homes in the city, then it melted snow on the streets, sidewalks, and bike paths, then was dumped back into the lake where it kept the harbor ice-free. That was a remarkable degree of heat recovery, but I don't know the actual efficiency.russ_watters said:Rejected energy is energy that isn't used for a purposeful activity, but that doesn't necessarily mean it "could be". Some can, some can't. So, some gets rejected because it is impossible to recover/re-use and some gets rejected because it is difficult to recover/re-use.
Modern combined cycle (steam turbine and gas turbine) power plants can achieve 62%.gmax137 said:A large modern natural gas burning plant can have a heat rate of 7500 Btu/Kw hr (that puts it near 45% thermodynamic efficiency).
Materials explored in the fusion materials research program have application in other nuclear systems, particularly fast spectrum systems.The ORNL Fusion Materials Program is embedded in the Nuclear Materials Science and Technology (NMST) group of the Materials Science and Technology Division, also drawing support from other groups in MSTD. The core of the Fusion Materials program is a team of scientists, engineers, and technicians who specialize in materials science and technology for nuclear applications. The research expertise of the group spans the development of novel materials, evaluation of the property changes and physical processes of radiation effects, to computational modeling and extrapolation of materials behavior in fusion energy systems. The current material systems in the Fusion Materials Program portfolio include conventional and advanced steels, nonferrous metals and alloys, ceramics and ceramic composites, and materials for magnets, plasma control and diagnostic systems.
Ouch. That could cause a headache for NY's power grid. Over the years, very many proposals to bring power to NYC from upstate NY were shot down. A lot of power comes down the Hudson valley, and Indian Point's location at the southern end of that valley made it key in stabilizing the grid.Astronuc said:Indian Point 3 will be shutting down permanently on April 30, 2021
The loss of Indian Point Unit 2 has been replaced by a combined-cycle gas-fired plant.anorlunda said:Ouch. That could cause a headache for NY's power grid. Over the years, very many proposals to bring power to NYC from upstate NY were shot down. A lot of power comes down the Hudson valley, and Indian Point's location at the southern end of that valley made it key in stabilizing the grid.
Welcome to PF!AndrewAndrew said:I for one am greatly for the use of nuclear plants. As it does release radiation, it is a very small amount. The amount of radiation from eating bananas in a year is 100x more radiation than what someone would receive living less than 50 miles from an active nuclear plant.
Along with that the dangers of a plant are very small when you really take into consideration how long plants have been active and that there is 440 some reactors in the world. As you mentioned, yes, nuclear plants do set radiation out and due to the vastly diverse locations the radiation does affect most people, the amount of radiation that people get just from the background sources such as the natural levels and cosmic rays makes up half of the radiation they receive in a year and almost 30,000x the amount of radiation that one receives from the nuclear plants.
I do understand your concern but I think that the efficiency and benefits outweigh the risks taking into account that the Chernobyl accident was also caused by misinformed employees.
Ringhals AB and Forsmarks Kraftgrupp AB each issued an Urgent Market Message (UUM) to the Nord Pool power exchange yesterday morning about the potential risk of Ringhals units 3 and 4 and Forsmark units 1, 2 and 3 being unable to restart following scheduled outages - in 2024 (F2), 2025 (R3-4, F3), and 2028 (F1) - because of a lack of storage space for used nuclear fuel.
The Nuclear Regulatory Commission has extended Dominion Energy's operating licenses for Units 1 and 2 at its Surry nuclear power plant in Virginia until 2052 and 2053, respectively. A previous license extension granted in 2003 allowed the two reactors to operate until 2032 and 2033.
The original 40-year licences were always intended to be renewed in 20-year increments, as the 40-year period was more to do with amortisation of capital rather than implying that reactors were designed for only that operational lifespan. It was also a conservative measure, and experience since has identified life-limiting factors and addressed them. The NRC is now considering applications for the extension of operating licences beyond 60 out to 80 years, with its subsequent license renewal (SLR) programme. As of January 2021:
- Reactors approved (to 80 years): Turkey Point 3&4, Peach Bottom 2&3.
- Reactors under review: Surry 1&2, North Anna 1&2, Point Beach 1&2.
- Reactors expected to apply: Oconee 1, 2&3, Brunswick 1&2, Catawba 1&2, H.B. Robinson, Harris, McGuire 1&2.
Astronuc said:"The Swedish management model for used nuclear fuel hinges on us being able to send the used fuel for intermediate storage as soon as it is possible to do so," Björn Linde, the CEO of Ringhals AB and Forsmark Kraftgrupp, told World Nuclear News.
Hint. Hint!Excavation of the first final disposal tunnel has started at the Onkalo underground used nuclear fuel repository near Olkiluoto, Finnish radioactive waste management company Posiva Oy announced today. The repository - the first in the world for used fuel - is expected to begin operations in the mid-2020s.
The focus on Stirling engines is interesting. The article does not discuss the expected electrical output, although an article published through ANS suggests 20 kWe, which is confirmed by the INL presentation below (gehinj-w15-hv.pdf). The temperature range would be useful for research on materials for some of the Gen-IV reactors. The power level (100 kWt) is rather low. In contrast, the Jules Horowitz Reactor (JHR) materials test reactor has a thermal output of 100 MW.21 April 2021 - The US Department of Energy (DOE) is planning to build a microreactor to help researchers and end-users understand how microreactors can integrate with other technologies. The Microreactor Applications Research Validation and EvaLuation (MARVEL) liquid-metal cooled microreactor could be operational within three years.
The MARVEL design is primarily based on existing technology and will be built using off-the-shelf components allowing for faster construction, DOE has said. It will encompass a 100 kW thermal fission reactor, based on the SNAP-10A design which was developed in the 1960s as a 45 kWt thermal nuclear fission reactor for use in space missions. The sodium-cooled reactor, with natural circulation cooling, will have an operating temperature of 500-550°C and will be fuelled by high-assay low-enriched uranium from available research materials. It will use Stirling engines to transfer energy from the core to make electricity.
Nuclear Fusion article - https://iopscience.iop.org/article/10.1088/1741-4326/abe4af01 April 2021 - Scientists at the US Department of Energy's (DOE) DIII-D National Fusion Facility have released a new concept for a compact fusion reactor design they say can help define the technology necessary for commercial fusion power. The Compact Advanced Tokamak (CAT) concept enables a higher-performance, self-sustaining configuration that holds energy more efficiently, allowing it to be built at a reduced scale and cost.
The CAT concept is described in an article published on 19 March in the journal Nuclear Fusion, and was developed from first-of-a-kind reactor simulations. The physics-based approach combines theory developed at the General Atomics (GA)-operated DIII-D facility with computing by Oak Ridge National Laboratory scientists using the Cori supercomputer at the National Energy Research Scientific Computing Center, and is based on development and testing of the underlying physics concepts on DIII-D.
If they can get the p-B11 cycle working, that would be a game changer!09 April 2021 - TAE Technologies, the California, USA-based fusion energy technology company, has announced that its proprietary beam-driven field-reversed configuration (FRC) plasma generator has produced stable plasma at over 50 million degrees Celsius. The milestone has helped the company raise USD280 million in additional funding.
Norman - TAE's USD150 million National Laboratory-scale device named after company founder, the late Norman Rostoker - was unveiled in May 2017 and reached first plasma in June of that year. The device achieved the latest milestone as part of a "well-choreographed sequence of campaigns" consisting of over 25,000 fully-integrated fusion reactor core experiments. These experiments were optimised with the most advanced computing processes available, including machine learning from an ongoing collaboration with Google (which produced the Optometrist Algorithm) and processing power from the US Department of Energy's INCITE programme that leverages exascale-level computing.
TAE said Norman nearly doubled its intended goals over an 18-month testing regime and has now demonstrated consistent performance of reaching 50+ million degrees Celsius, replicated over many hundreds of testing cycles - all in a compact machine that has very attractive economics when scaled up to a full power plant. With this most recent milestone, TAE has now unlocked the 'hot enough' conditions needed to scale to a reactor level performance.
TAE's approach to fusion combines advanced accelerator and plasma physics, and uses abundant, non-radioactive hydrogenboron (p-B11) as a fuel source.
Some of the capital will be used to begin development of a demonstration facility, called Copernicus, that will operate well in excess of 100 million degrees Celsius to simulate net energy production from the conventional Deuterium-Tritium (D-T) fuel cycle. Copernicus will provide opportunities for TAE to license its technology for D-T fusion, while scaling to its ultimate goal utilising p-B11.
I can’t see the legal/regulatory issues ever making a 20 kW nuclear power plant viableAstronuc said:The article does not discuss the expected electrical output, although an article published through ANS suggests 20 kWe, which is confirmed by the INL presentation below (gehinj-w15-hv.pdf).
The 100 kWt (20 kWe) is a demonstration module. I would expect micro-reactors to be larger, and perhaps be used to district heating, as well as electricity. I don't know how such a plant would be scaled up with Stirling engines. An efficiency of 20% is rather poor.Dale said:I can’t see the legal/regulatory issues ever making a 20 kW nuclear power plant viable
My bold for emphasis.The U.S. Nuclear Regulatory Commission (NRC) is working to have an effective and efficient mission readiness for reactors that differ considerably from those currently licensed. Micro-reactors, that is, reactors that have a thermal power of no more than tens of megawatts, are one class of these advanced reactors. This report is to articulate the technical and regulatory issues that will need to be addressed for NRC to have the ability to review licensing applications for micro-reactors. Many of the issues center around the fact that a) these reactors may be operated remotely and/or semi-autonomously and b) it will be difficult to analyze risk from new, unique, technologies. Initial thoughts are given on how probabilistic methods could be used to determine risk and how the current approach for reviewing non-power reactors could be useful for micro-reactors.
https://www.world-nuclear.org/infor...ycle/uranium-resources/supply-of-uranium.aspxThe world's conventional identified uranium resources amounted to 8 070 400 tonnes of uranium metal (tU) as of 1 January 2019. These represent all reasonably assured and inferred uranium resources that could be recovered at market prices ranging from 40 to 260 USD/KgU (equivalent to 15 to 100 USD/lb U3O8).
You can use any electricity that's on the grid; even baseload nuclear energy that isn't easy to throttle.Mayhem said:Question: Could you use green energy to enrich uranium for reactor use? Sometimes wind mills will produce excess energy at night due to low consumption and high winds.
Dale said:I can’t see the legal/regulatory issues ever making a 20 kW nuclear power plant viable
Well, I'll go a step further and/or clarify: I think modular construction has significant benefits for improving the existing large plant paradigm, but that's it. The legal/regulatory issues make site selection one of the biggest hurdles in plant construction, and building more small plants makes the problem worse, not better. The security issues and costs would be worse with small plants as well.Astronuc said:The 100 kWt (20 kWe) is a demonstration module. I would expect micro-reactors to be larger, and perhaps be used to district heating, as well as electricity.
That is a good point. Standardization and cross training would be easier, and site design would be simplified.russ_watters said:I think modular construction has significant benefits for improving the existing large plant paradigm
Yes. According to the NuScale paradigm, there are two (or three) principal objectives.russ_watters said:Well, I'll go a step further and/or clarify: I think modular construction has significant benefits for improving the existing large plant paradigm, but that's it. The legal/regulatory issues make site selection one of the biggest hurdles in plant construction, and building more small plants makes the problem worse, not better. The security issues and costs would be worse with small plants as well.
The benefit I see to small reactors is that it may be able to rapidly mass produce them in a factory, which could shorten construction and economic payback timelines. The "plant" would then be mostly electrical infrastructure, and once that's completed you could start lining/piling-up the modular reactors one at a time, connect and commission them and start generating power (and more importantly, income) faster.
The original designs for containment assumed that the US would never be attacked so that the plants would never experience an artillery barrage or bombing by air. Of course, all that change on September 11, 2001.etudiant said:Although the economic benefits of a small reactor appear compelling, the regulators are certainly also conscious that suicide squads are now an established aspect of terrorism.
It will be a challenge to design an effective and yet terrorism resistant SMR.