The Fisker thread, esp. comments by CajunLawyer and Steelslaver made me try to remember the state of matter vs. energy in the universe. Einstein's formula of mass - energy equivalence and the conversion of matter into energy.
Is there a finite amount of energy and are we just robbing Peter to pay Paul using up resources to appease so called GreenKeepers?
Would we be better off just going nuclear to provide our enery needs despite the long term storage of used fuel?

From a purely selfish perspective, I did great working in the nuclear energy field (until TMI), but as a retired consumer, there are lower cost options for the end user.
A recent contact to build a solar photovoltaic power facility was awarded at a price that beat every other form of power generation.
Then there's also the option to plop some panels on your roof and even go off grid, which is appealing.

"Record-Low Solar Prices Drive Middle East Projects" Record-Low Solar Prices Drive Middle East Projects


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Slava Ukraini!

I am not a physicist, either, but from what I've read, the calculations show an imbalance between energy and matter in the universe, and the physicists came up with the concept of dark matter/dark energy to account for that. As far as I know, they're still trying to figure it out.

As for nuclear power, I have read that there are scientists who say that we should be expanding our use of nuclear reactors as the environmental benefits outweigh the negatives with improvements in technology. I think fusion power is the "holy grail," since the fuel is a hydrogen isotope and the waste produced is helium, but it's been studied for decades and I don't think anyone's come up with a viable fusion reactor capable of producing sustained reactions/power. On the fission side, I've read that some scientists have been advocating the use of thorium for fuel as its more plentiful than uranium and produces less nuclear waste.

Of course, I could be wrong as it's been several years since I've read all this and things may have changed since then.

Short answer: I dunno.

Battery technology has to get better is my understanding.

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Hue 68 noli me tangere

We should be finding out soon if those scientists are correct.
I took a field contract in 1983, for the piping contactor Pullman Power Products, on the Alvin W. Vogtle Electric Generating Plant in Waynesboro GA., for building Unit 1 and 2. They were commissioned in 1987 and 1989.

There are two new units there, in the final phases of construction, that should be commissioned within two years. Expected cost 25 billion dollars. It will be an interesting opportunity to compare the two generations of commercial viability, science, and technology.



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Slava Ukraini!

I think it’s impossible to have a serious conversation about low carbon no carbon power without discussing nuclear. Unfortunately, its been so taboo the last forty years theres been no meaningful funding for reactor
research and development .

Energy equals Mass times C squared. C being the speed of light. Light travels at 186,000 miles per second squaring itt gives you a fairly large number.

But, nuclear doed have its limits going with fission. First at present you need a bunch of very large kind of unstable elements like plutonium or uranium. A mass of one of these placed in close proximity causes its atoms to bombard each other somewhat like cue ball striking a rack of balls, but the collisions continue as the partials keep striking others. This causes a large release of heat. If the heat is used to boil water it will turn a turbine and generator stet. But, there is a limit to the amount of currently fissionable material . Plus, the radioactive waste is a problem. Waste can be cut down by recycling the material and reusing it to create more fission, heat and power. As a piping a pressure vessel "guy" I believe we can produce and maintain safe plants at a cost.

I worked for a superintendent who had build nuke plants for Bectal. He said the main problem was every company wanted their own design. Making one offs is always more expensive than making lots of the same. Plus, he said the inspections were nuts. He got the reactor portions, but said they also required inspection of the plumbing in the bathrooms. Any piping in the plant had to be inspected by a authorized nuclear piping inspector. Now the navy runs all the same power plants in their subs and carriers. Has a bunch of them tended by mostly kids (smart ones though)and they don't have problems. When they are all the same if one has a problem you have a huge knowledge and experience base. Find a problem with the design you can retro fit them all. With a one off if you have a problem (Three Mile Island) you the only ones that knows how it works.

Now a fusion reactor would change everything if we could control it. With fusion instead of splitting atoms you join them. 2 hydrogen atoms are forced thereto to form a helium atom. This produces in the neighborhood of 4 times more power than a fission reaction by mass. But as hydrogen is extremely light with an atomic weight of 1.00784 and uranium 235 has an atomic weight of 235.044. Either is millions of times more powerful than any chemical combustion like burning gas, coal etc.

Great thing about fusion if we could harness it is hydrogen is very abundant. I read the statement that if we could harness fusion we could continue to use electricity in ever increasing amounts and in 10,000 years only lower the volume of water in the ocean 1 inch if we used the H in water for our hydrogen.

Solar, The sun hits us with a huge amount of energy every day. The sun is a giant fusion reactor BTW. Current solar panels have a efficiency of around 15-22% normally and they can be effected by wind, hail, heat, ice snow etc etc. But, there is another way to harvest solar. Reflect and concentrate it. A curved surface does this. A nephew of my late wife is an engineer and works at a solar plant in Nevada. Long series of curved mirrors with a pipe in them set up so the light that strikes the mirrored concentrated on the pipe. Somewhat like a magnifying glass works. A large area of this collects enough heat that it powers a steam turbine which turns a generator. More efficient than any solar panels per amount of area. When I told him of my idea of using the big original style of satellite dishes coated with mirrors and setup to track the sun to collect and focus sunlight on balls of water placed where the signal gathering LNB originally was. Place balls of water in series on a bunch of dishes and it would boil, produce steam and run a closed circuit steam turbine. He estimated you could run 200 amps of 220v with about 15 of them. No normal house ever hits 200 amps. I can run 2 welders and a bunch of power tools at tithe same time while my house if running all its normal stuff and never come close.

Concentrated solar used to produce steam is more efficient means of gathering power. It does require maintenance of the turbine gen set as does gas combustion turbines, coal fired, plus conditioning of the boiler feed water. Even hydro electric requires some turbine maintenance. But the degradation is pretty slow on these when compared to solar panels.

Without getting to scientific, the electric generated by large power plants (nuclear, water turbine whatever) is more efficient than thousands of IC cars polluting the atmosphere. No one complains about turning on a switch in their homes and running hundreds of electric devices.??

Electric cars also produce some electric in regenerative braking,


True the electric has to be produced somehow and there is a loss in converting it to batteries but it will get better and still better than using gas. Put a solar panel on the roof of cars.

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Still Running Against the Wind

Lot easier and more efficient to run one than 10 thousand. One fuel tank and pump vs 10,000, One combustion chamber vs 60,000, One exhaust and exhaust scrubber and catalytic converter vs 10,000. One generator vs 10,000 transmissions.

Typical thermal efficiency for utility-scale electrical generators is around 37% for coal and oil-fired plants.

Modern gasoline engines have a maximum thermal efficiency of about 20% to 35%

But there are a couple of other things to consider as of this time. Most of the batteries are Lithium based. Lithium mining and refinement itself is hardly eco friendly and the disposal of the toxic used up batteries is going to become a serious problem at some point in the not to distant future,

I like the idea of Hybrids,. Small internal combustion motor to charge batteries on the go. When the motor does run it runs at the right power production. No idling, no lugging just a constant rpm that is designed for peak efficiency. . Less battery storage capacity needed. Torque of electric motors and the dynamic braking energy can be used to put power back in battery instead of just being burned on as wasted friction heat like happens with brake pads

I don't have the energy to talk about this at 7:30 in the morning

My electric bill is less than $100 during winter and around $225 this time of year. Lat's say $175/ mo average. My next door neighbor had panels put up 2 years ago for $40K. Their electricity bill is maybe $50/ mo now and can be negative in winter. The 20 year note on the panels is $250/ mo. I want to be green but........ Oh and when the power went out a couple weeks ago they were dark as the rest of us. The "Elon Musk" battery pack is extra, lots extra. Joe

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Wisdom chases me; I'm faster

IME, the biggest issue with commercial nuclear power has been humans (imagine that). Theoretically, very safe. But when you throw in management with production quotas, people start taking shortcuts that can impact safe operations. That’s across the entire supply chain - parts to engineering to operations.

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Vegan by proxy.

For your consideration: a mild-mannered 64-year-old man picked up his laptop computer, clicked on the top link in his favorites list to enter a familiar place in his daily routine, and found himself in...

....the Twilight Zone.

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Ukraine -- now more than ever

It has all been debated to death in other Tesla threads.
Lets talk about the best gun cleaner/oil!

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Still Running Against the Wind

Or you could just skip over the theads you’re not interested in.

I was looking for the “Best gun cleaner/oil” thread you started, but I couldn’t find it. Where’s that at?

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Vegan by proxy.

I think this (actually old just not the route nuclear took early on)new technology is very promising. It addresses the waste issue and is far more efficient.
A Very Fast, Very Safe, Very SLIMM Nuclear Reactor

Everybody likes a little ***, nobody likes a smart ***.

Interesting article. The one thing that crossed my mind - wasn't there some big safety issue with the sodium reactors they had at Rocky Flats and INL?

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Vegan by proxy.

A smart feller by the name o' George Friedman
conjecturated that the genuine "next big thing"
will be space based solar. No clouds, no
nighttime, virtually no limit on dimensions...
there's a figure on how much efficiency increases,
without miles of atmosphere abating sunlight,
and I cannot recall it.

Research on transmitting the energy down to
earth has been going for over a decade. High
power microwave beam is apparently the
method.

Space-based solar power - Wikipedia

I should've stayed at a Holiday Inn Express last night!

I have heard that the "etc." also included accumulated dirt, so some way needs to be implemented to clean the panel every so often. They may have to develop a drone to do it because I'm not going to climb up on the roof.

Thank you for putting together a nice, tight essay on energy sources that this non-scientist could understand.

An advanced sodium cooled reactor called the Fast Flux Test Facility at the 400 Area of Washington state's Hanford Reservation was an exceptional design.

In April, 2006, the FFTF was honored by the American Nuclear Society as a "National Nuclear Historic Landmark". Achievements cited include:
Radiation exposure to operators was 1/100th of commercial power reactors.
Established a world record for fuel performance.
Produced extremely high quality rare radioisotopes for medicine and industry.
Conducted the first passive safety testing.
Demonstrated commercial viability of breeder reactor components, materials and fuels.
Provided fundamental experimental data for fusion programs.
Advanced the fuels and materials development for space nuclear power.
Demonstrated miniaturized reactor test techniques.
Demonstrated the feasibility of transmuting radioactive technetium-99 into a non-radioactive element using a reactor. Technetium-99 is one of the most troublesome long-lived components of the nuclear waste stream. Processing out this isotope and destroying it, permanently reduces the risks associated with long term storage.

Fusion power has been 20 years in the future for the last 40 years.

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"He was kinda funny lookin'"

...which was called the V.C. Summer project by Santee-Cooper which covers a wide area of eastern SC?

They got the facility about 3/4 built, ran out of money and Westinghouse, the producer of the nuclear plant, got out of the reactor business. The project has now been abandoned.

There were some halfhearted plans to renew the contract but nothing worked out.

There's a lot of finger pointing and mismanagement and while they swear that the customers won't have to pay for it, what do you think is going to happen?

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"He was kinda funny lookin'"

Nice thing about sodium is it would be way harder to boil off the sodium than water. Boiling away the medium causes a runaway reaction like happened at Three Mile Island. The sodium is super heated and is flowed into a heat exchanger with water on the other side, heating the water to produce steam and finally turn the turbine genset.

Sodium can also be used in a solar heat collector. Because sodium can get extremely hot with out boiling it can be used to store heat and the solar plant can keep running after thee sun goes down using the heat stored in sodium to keep producing steam. Not shutting down is of course best, Starting and stopping anything is seldom efficient.

Sodium boils at 1,621°F or 882.8°C. That is 8.8 time higher than water.

Sodium is liquid at 208f or about 98C. It turrns to a liquid about the time water boils,

True, but it should happen someday. Steam only took modern man 200,000 years to figure out. That was in 1698, fission reactor came along in another 244 years (1942) That was just 78 years ago and it took another 14 more years to go commercial. The steps get closer together. We have run a fusion reactor for very brief periods so it is possible.

Amusing that you should mention the Hanford Nuclear Reservation. Possibly the "hottest radiological area" in the continental US except for the NM proving ground. I visited there a couple of times while giving seminars at the DOE's labs just off the site. The stories behind the railway loops that stretch off into the distance are something that nobody there wanted to comment on. That was the Plutonium production plant for Little Boy and its companion lab in Oak Ridge TN was the Uranium enrichment plant for Big Boy. I spent time there as a post-doc in the late 1960s growing large quantities of microbes for various uses and the stories were "amusing", including 6 lane highways to nowhere.

On a slightly different note, I think that part of the problem with the US Nuclear Industry was that each manufacturer wanted their own design and technique, whereas the European nations decided on one or two designs and then went with the best one for the money. The Dounray (sp) fast breeder reactor in the NW of the UK has been running successfully for over 50 years, as have both French and German equivalents. Dave_n

Some time ago somebody made a calculation that the amount of the Sun's energy falling on a certain area of Nevada was sufficient to power the entire nation.

Of course, it was a total coincidence that the area almost exactly matched that of the Nevada test site and the Nellis test ranges.

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Release the Kraken

Lived there in Kennewick from 1989-90 while working the "areas", and its too bad it's so radiological there, because it's a beautiful region. On the bright side, there will be 100 generations of employment there, keeping the contamination in check and out of the Columbia River.

Talk about closing the barn door after the horse ran off, after TMI and the shutdowns started, the big engineering companies got desperate and created standardized reference designs, but too late to stop the bleeding in the industry.

From the good old job-shopping days. Didn't usually have a camera when working at the sites, but got hubby to pose for this at the Shearon Harris plant in New Hill, NC about 38 years ago, on contract to CP&L.

e=mc^2 is a special case. It's only true if the object is at rest in relation to the observer. Otherwise e=gamma mc^2. C is the speed of causality, 2.998x10^8 m/s.

Your welcome.

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9tenz

Thanks 2.998x10^8 m/s. is the speed of light in a vacuum. causality is an interesting topic and concept.
BTW you can show ² by using the alt key and typing 0178 on the numerical part of the key pad. To cube ³ type 0179

Your welcome

Well, I am a physicist and have been working both ends (nuclear structure and nuclear engineering ) for a number of years.

A few facts:

Nuclear power is the safest way to make electricity. Safer than windmills, solar panels, coal etc.

"Spent" fuel is hardly that, it 's just that the amount of fissile materials has dropped below what will sustain a reaction in a thermal reactor.

Moving on to fast regime reactors opens up a virtually unlimited supply of fuel- Just the depleted Uranium at Savannah River has enough energy to power the US for the next 700 years- and that's no mining etc.

Nuclear is "renewable". With seawater extraction, presently being worked on by multiple groups, there's no limit on the supply side.

By burning all the fissionable materials, Fast reactors only "waste" is fission products. These are only "hot" for a couple hundred years and easily sequestered by vitrification.

THERE IS NO NUCLEAR WASTE PROBLEM. It was solved decades ago. All the spent fuel on the US fit in one football field, staked about 70' high. Compare that to a coal ash pile near any power plant.

It really frosts my cookies to see garbage like the recent "Chernobyl" show. You can't catch radiation like a cold, what total BS.
Even with all that, aside from the increase in easily curable thyroid cancers, there has been no discernible increase in cancer rates across Europe.
Fukushima is even more stark. NOT ONE CASE of radiologically induced cancer from the accident.

I recommend you read this book, it's written by a friend of mine, Michael Shellenberger, and really hits the nail on the head with how it's not only possible , but necessary to improve the lot of mankind to save the environment.

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SWCA #3356, SWHF#611

I'm not smart enough to figure out computer keyboards.

The speed of light isn't about light. Light just travels at the speed of causality, if you will. Nit-picky I know.

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9tenz

Wind and solar will never work. Once you add in the batteries etc to make it 24/7 it's no longer viable economically. Looks at this:
Energy returned on energy invested - or how much you get out from what you put in. Pay close attention to the "buffered" numbers- that's inlcuding all the ancillary stuff you need to make unreliable wind and solar provide power 24/7.

The one all the way to the right is a fast neutron reactor.

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SWCA #3356, SWHF#611

One of a slew of new "fast" reactors. It's hard to keep up.

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SWCA #3356, SWHF#611

I spent 4 years doing nuclear power plant service. A few comments on points raised above:

Yeah, in the beginning the nuke industry did custom builds trying to meet the utilities perceived wants. Then Westinghouse developed the Standardized Nuclear Power Plant System (SNUPPS) where besides being standardized, maintenance needs were considered and designs changed to make replacement of wear parts (like pump seals) much faster/easier. Maintenance outages were much faster/cheaper. Reactor coolant pump seal service went from ~7 days(included motor inspections/service) to 8 hours (seal service only). Even the motor inspections could be done without having to pull the (~7000 hp) motors.

Unfortunately, only 3 plants/ 5(?) units of the SNUPPS design got built before the industry stalemated.

Peanuts Carter killed off both the breeder reactor project (makes fuel and power) and a prototype system where low level radioactive waste was to be burned and then the ash sealed in molten glass to prevent any possible leaching into the ground.

I've gotta question the radiation exposure claim on the sodium reactor vs a commercial plant. First off, what are the comparative sizes and outputs in megawatts of usable power?

Actually solar needs no batteries if they use reflected heat to heat sodium. Heat is stored in the sodium and then used over a 24 hour period. Controlling the flow of sodium flow controls the rate of energy supplied to match demand.

No expensive panels, no batteries. just a bunch of reflectors heating sodium and insulated tanks to store part of it in, a couple tanks for makeup water for the steam turbines located in places like the Nevada desert where cloudy days seldom occur. The sodium is passed through banks of heat exchanges transferring the heat to water, boiling it. The sodium goes back to the tanks and reflector piping for reheating. The steam goes to multi stage steam turbines gen-sets, spinning them and producing electricity. The steam leaves the turbines as hot condensate water and is then passed back through the exchanges to be turned back into steam. As long as all the heat in the sodium is never transferred to steam before the sun shines again in the morning it never quits producing electricity.

Delcrossy

Thanks for the great post on the improvements in modern reactor design.

causality,
I think of it as kind of the fastest speed of things happening. The rate of cause and effect. Effect can not occur prior to cause.

No actual agreed upon definition

One can build either LWR (Light water reactors) or Sodium cooled fast reactors in any size one wants.

The French Superphenix was rated at 1400 MWe (same as a large commercial plant) and the presently running Russian BN-800 is rated at 800 MWe- on the grid as we speak.

First serial batch of MOX fuel loaded into BN-800 : Uranium & Fuel - World Nuclear News

GE/Hitachi's PRISM is on the small side at IIRC 400 MWe, but they're to be built is multiple sets.

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SWCA #3356, SWHF#611

MWe is mega watts of electricity.
A MWe will supply about 400-900 American homes depending on a bunch of stuff. First of all none of them run at 100% 24-7,
Probably more like around 400 during peak demand hours

The 2 biggest coal fired generator in Colstrip Montana units 3and 4 produce about 740 each and together hey burn about 10 million tons of coal a year

The largest coal fired is in China at 6,720MWe

Current largest nuke S Korea at 7,400MWe

Dwarfed by hydro electric from Three Gorges dam in China 22,500 MWe

The key to worthwhile debate is education.
I'd like to thank the members who chimed in with real world experience and those with a wealth of information.

Question, what is this sodium you talk about? Is it the pure element or a salt like, well, salt? Sodium by itself sounds kinda dangerous if the water lines develop a leak.

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9tenz

This is a Sodium tech company working on a newer design that explains the system well.
The Science - Transatomic

Note the "freeze plug" in the Transatomic schematic. The explanation in the accompanying article is very relevant.

From Wiki

The primary advantage of liquid metal coolants, such as liquid sodium, is that metal atoms are weak neutron moderators. Water is a much stronger neutron moderator because the hydrogen atoms found in water are much lighter than metal atoms, and therefore neutrons lose more energy in collisions with hydrogen atoms. This makes it difficult to use water as a coolant for a fast reactor because the water tends to slow (moderate) the fast neutrons into thermal neutrons (though concepts for reduced moderation water reactors exist). Another advantage of liquid sodium coolant is that sodium melts at 371K and boils / vaporizes at 1156K, a total temperature range of 785K between solid / frozen and gas / vapor states. By comparison, the liquid temperature range of water (between ice and gas) is just 100K at normal, sea-level atmospheric pressure conditions. Despite sodium's low specific heat (as compared to water), this enables the absorption of significant heat in the liquid phase, even allowing for safety margins. Moreover, the high thermal conductivity of sodium effectively creates a reservoir of heat capacity which provides thermal inertia against overheating.[1] Sodium also need not be pressurized since its boiling point is much higher than the reactor's operating temperature, and sodium does not corrode steel reactor parts.[1] The high temperatures reached by the coolant (the Phénix reactor outlet temperature was 560 C) permit a higher thermodynamic efficiency than in water cooled reactors.[2] The molten sodium, being electrically conductive, can also be pumped by electromagnetic pumps.[2]

Yes, sodium reactivity (chemical) is a problem. But the only time it is close to water is when inside a heat exchanger that is also a pressure vessel. This part can be avoided by passing the sodium through a exchanger against another non reactive (chemically) liquid medium and then the non reactive medium is passed by water to produce the steam.

I have worked inside a sodium plant. It is an interesting metal.

Yees sodium is actually a metal

I'm not a physicist. I was a dual career guy that spent 12 years in engineering before going into healthcare. 5 of those 12 years were designing mods and working outages on commercial nukes. I had a year of BWR time and 4 years in a small PWR. Not an expert, but not just guessing either.

When I see the new style nuke plants, the "day 1" safety looks pretty impressive, but I don't see things that give me a warm fuzzy about a 20 year safety record. Beyond the management pressure to meet production quotas I mentioned a few posts back, I have two concerns.

1) The degredation that occurs when real humans (pipe fitters, electricians, etc.) replace worn out parts and repair corrosion damage. The field repairs are never as good as the original build. Even if the same craftsmen do the work. You can QC from now until the cows come home, but it's never as good as the original build.

2) IMO, there's a flaw in the accident design basis for commercial nukes. Back then, and AFAIK still, the accident design basis was based on the assumption that the damage from a singe, independent accident initiating event would be corrected before a new independent event occurred.

I can think of two cases where that didn't work. The first was a few years ago at my old PWR where a flood shut down the back up diesel generators and before the generators could be brought back online, there was a fire in some switch gear independent of the flood, that caused a loss of offsite power. Something similar happened at Fukushima - with worse consequences. The earthquake knocked out offsite power and the tsunami knocked out the diesel backup. The Fukushima design could handle one or the other, but not both simultaneously. If that happened at a coal or gas turbine plant, not a big deal. What accident scenario are they missing with the new style plants they haven't considered that would be no big deal for a coal/gas plant but would be huge in a nuke?

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Vegan by proxy.

Pretty much my point. A tiny prototype reactor being run for T&E purposes (pretty much lab conditions) and a 900+ MW unit might have issues of scale that might affect results.

I worked with an engineer who'd spent some time working at an experimental nuke plant in Idaho. Don't recall plant details after 30+ years, but he had a few... interesting stories about the place.

There's two directions of engineering development with these.
One uses molten salts ; either chloride salts for fast reactors or fluoride slats for thermal reactors. Here's a (kinda dated) wikipedia article concerning molten salt reactors:

Molten salt reactor - Wikipedia

There's a lot of research interest in these as they do not need to be powered down for refueling- refueling and fission product removal can be done "on the fly".

The other direction is to use metallic sodium. As you note, it does require careful handling, but as demonstrated at the Monju plant in Japan, a sodium leak while a mess, isn't catastrophic. The BN-800 in Russia is metallic sodium cooled, as was the US experimental fast reactor program (EBR-1, EBR-II, IFR).
In the event of a leak the sodium converts to Sodium Hydroxide,which is a solid.

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SWCA #3356, SWHF#611

We're getting pretty good at scaling, as compared to the '50's when Shippingport was built. The new plan is to use multiple smaller reactors ganged to drive the turbines rather than the "One Big Reactor. One Big Turbine" setup of present plants.

I'll bet! INRL was pretty wild and wooly back in the day.

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SWCA #3356, SWHF#611

As it turns out , TEPCO (Fukushima's owner) was aware of the possibility of flooding to the diesel backup and decided not to relocate the generators. Here in the US, multipoint failure scenarios are part of the failure source terms. NRC wouldn't issue a license otherwise.

We should also note that the Fukushima reactors are the old GE Mk1 design. We've learned a lot since those were originally drawn. There's no Mk1 plants operating in the US that haven't been upgraded.

In the end analysis, LWR's (both PWR's and BWR's) while great for submarines, aren't really the best choice for large scale power generation. Rickover latched onto the design since they were perfect for his application and everyone followed suit.
For example, a loss of coolant flow test was performed at EBR-II (sodium cooled fast reactor) at INEL. They had the reactor running at full power, scrammed it and turned off the coolant pumps. The core temp rose a few hundred degrees, stabilized and fell off without any operator intervention. No damage to the plant. You really wouldn't want to try that with a LWR!

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SWCA #3356, SWHF#611

Unless it's changed recently, plants needed to be able to operate with multi-point failures, but only from single, independent initiating events.

A real example might be a plant on the lower Missouri River. The design basis is to be able to safely shutdown in the event of 7.5 magnitude earthquake on the New Madrid Fault similar to the one in 1811 (that was our design basis seismic event). The plant is also designed to safely shutdown in the event of 1,000 year flooding on the Missouri River.

The design basis assumes both those things are independent events that won't occur simultaneously or nearly simultaneously. The assumption is there's enough time to repair the damage from one initiating event before the next initiating event occurs.

Where that assumption falls apart is if the earthquake on the New Madrid Fault is strong enough to cause a breach in the Corps of Engineers dam on the Missouri River at Yankton and the dam fails. For an earthquake that size, that's a realistic possibility. Kind of similar to an earthquake followed by a tsunami. Now you have two catastrophic events occurring simultaneously, when the design basis of the plant is to only deal with a single initiating event at a time.

Maybe the NRC has changed those requirements in the last few years. That's how it used to be.

Anyway, great discussion.

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Vegan by proxy.

Yep. Final rulemaking was last year.

Federal Register
::
Mitigation of Beyond-Design-Basis Events

This rulemaking was a direct result of the multisource failure at Fukushima-Daichi 1-4.

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SWCA #3356, SWHF#611