Showing posts with label Diablo Canyon. Show all posts
Showing posts with label Diablo Canyon. Show all posts

Sunday, April 30, 2017

Diablo Canyon Nuclear - Power Replacement via Solar

Subtitle: Replacing Nuclear with Solar also Requires Storage

An interesting question was posed to me on Dr. Curry's post recently at her blog Climate Etc. The question and my answer are shown below, but first a bit of background. 
Diablo Canyon Nuclear Plant, via Google Maps 2016.
Arrow idicates twin reactors.   Pacific Ocean to the bottom right. 


California has but two nuclear power reactors left running, both at the Diablo Canyon nuclear plant near Morro Bay, right on the Pacific Ocean shore.  The 40-year operating license for each reactor expires in a few years, and PG&E announced it will not seek a 20 year license extension but will shut them down in 2024 and 2025, respectively.   Also, PG&E announced it would compensate for that power by a mix of renewable energy, conservation, and grid storage.  My June, 2016 article on this on SLB is at this link.   The increased renewable energy likely poses several issues for the grid operator.   


A commenter on Dr. Curry's post put the following question to me:

“. . .does California have enough regulatory authority to demand PG&E replace Diablo Canyon only with the renewables and with energy conservation measures; and further, to directly and explicitly prevent PG&E from placing greater reliance on natural gas for servicing California’s electricity demand?”

The short answer is probably Not. The long answer is more complex.

Renewables generation in California are regulated under multiple regulations, including (but not limited to) the RPS (Renewable Portfolio Standard). see link to   http://www.cpuc.ca.gov/RPS_Homepage/

The law requires PG&E (and other Public Owned Utilities) to procure 33 percent of their power sold in 2020 from renewable sources. PG&E is reported to already have under contract 43 percent renewables for 2020.

The next milestone for RPS is 50 percent by 2030. Clearly, PG&E must find a source of more renewable energy to meet the 50 percent requirement. With Diablo Canyon nuclear to close the reactors in 2024 and 2025, that gives PG&E an opportunity to obtain approximately 2,200 MW of power from renewable sources. However, RPS does not work on installed capacity, it requires kWh delivered to be from renewables.

As most everyone knows (and detractors cannot stop shouting it), wind and solar renewable power do not run 24/7, they have approximately 25 percent annual capacity factor in California. Thus, about 8,800 MW of either wind, solar, or both, would be required to replace the retired nuclear output. However, installing that much renewables would likely create grid issues, and put PG&E in the 60-percent range for RPS.

The state does not have very much, if any, untapped wind resources left, so the new installations will be solar. The economics of solar thermal are not as good as solar PV, therefore the new installations will be solar PV.

The main point is that solar PV must have some form of backup due to intermittency with sunshine. Those aspects are well known, from night, to clouds in daytime, to seasonal variation, to solar eclipses (a big one is coming in August 2017), and to normal outages for maintenance.

The usual backup in California is natural gas-fired plants that use combined cycle gas turbine (CCGT) technology. Indeed, CA law requires a minimum efficiency for fossil power plants that essentially dictates that only CCGT can be built. Therefore, it is safe to conclude at this time that PG&E will very likely build, or purchase power from, approximately 8 to 10 GW of new solar PV in the next 7 to 8 years. That will also require the installation of some amount of gas-fired CCGT.

The situation would change if and when grid-scale batteries (or other storage) are sufficiently economic to be installed for baseload power. The economics for batteries are already good for peaker power plants. Whether the battery installed cost declines sufficiently by 2022, when investment decisions must be made, of course is not yet known.

I do not always agree with what Planning Engineer writes, but on one thing we do agree: a large amount of solar power on a grid creates the problematic Duck Curve. California is already managing very well with a substantial Duck Curve, with recent numbers showing thermal generation in mid-day at 11 GW and 26 GW at the peak 8 hours later (data from 4/29/2017).

However, if an additional 8 to 10 GW of solar generation is installed, the grid would have thermal generation of 2 to 3 GW in mid-day, then must produce 26 GW only 8 hours later. That is a problem for the grid planners and operators. It remains to be seen how all this will play out.

Roger E. Sowell, Esq.
Marina del Rey, California
copyright (c) 2017 by Roger Sowell - all rights reserved


Topics and general links:

Nuclear Power Plants.......here
Climate Change................here  and here
Fresh Water......................here
Engineering......................here  and here
Free Speech.................... here
Renewable Energy...........here  


Wednesday, June 22, 2016

California to Close Diablo Canyon Nuclear Plant

Subtitle: Solar Power to Replace Nuclear

It won't be right away, instead the closures of the two remaining reactors in California will be in 8 and 9 years from now, respectively, in 2024 and 2025.   That news rang across the nuclear camp yesterday, as PG&E, the plant's owner and operator agreed to shut the plant down at those dates and not seek a 20 year extension for the operating license.  Many articles on this are available, one from the Wall Street Journal (see link) does a credible job.   Title: "PG&E to Close California’s Last Nuclear Plant by 2025 - It will be cheaper to shut down Diablo Canyon facility and find replacement power, utility says."
Diablo Canyon Nuclear Plant, image from Google Maps 2016
Arrow indicates twin reactors.   Pacific Ocean to the bottom right.


There are some interesting, biased, pro-nuclear articles too, mostly from those who seemingly cannot believe their beloved nuclear plants are being shut down, instead of being built in greater numbers.   Those articles grind on and on with their favorite themes: jobs lost if nuclear plants close, grid instabilities if nuclear plants are not there to anchor the fragile grid, save-the-planet with carbon dioxide-free power from nuclear plants, and of course the old stand-by, coal and natural gas prices might increase again someday.   What many of the pro-nuclear articles omit is the great capital cost that PG&E would incur to keep the plant running past 2025, and how much money the plant is losing by operating in the present economic conditions. 

Much of the hoopla and angst stems from the pledge by PG&E, one of California's largest utilities, to replace the 2,200 MW of electricity presently provided by Diablo Canyon with a mix of wind, solar, storage, and efficiency improvements - all at no additional cost to the consumers electricity bills.  

Taking the above list of four tentative reasons to keep the nuclear plant online, in order, with jobs first.   The plant employs approximately 1500 people, per PG&E.   Jobs and their loss are also trotted out by other nuclear plant owners across the nation, as those plants are shut down.  The company is to work with various unions to keep some employed to perform the decommissioning (more on that expensive fiasco later), transfer some to other jobs within the company, and perhaps provide severance packages to others. 

Second, the California grid is not at all fragile.  The simple fact is that Diablo Canyon is a drop in the bucket in the California electricity market; only 2,200 MW out of approximately 35,000 MW average production, or approximately 8 percent.   On a high-demand day, when demand reaches 45,000 MW (as it did yesterday), the nuclear contribution is a much smaller portion at only 5 percent approximately.  It is also a fact that another, equal-sized nuclear power plant dropped offline forever in 2012 when the SONGS (San Onofre Nuclear Generating Station) had multiple tube ruptures and spewed radioactive steam into the sunny skies of Southern California.   SONGS' 2,200 MW removal from the grid did not create any blackouts, rolling or otherwise.   The ISO, California's Independent System Operator, simply called for more production from the gas-fired power plants.    Also, in the four years since that time, California has installed at least 7,000 MW of solar power plants.   The grid's frequency stability is assured by the gas-fired power plants, and large hydroelectric plants.  

Third, saving the planet by producing power that is free of carbon dioxide emissions is required only by the false-alarmists who believe that CO2 will overheat the Earth's atmosphere.   CO2 in the atmosphere certainly has not produced any appreciable, nor alarming warming thus far.  

Fourth, the tired ploy of gas shortages that nuclear advocates used in the 60s, 70s, and 80s no longer works.  Natural gas is no longer in short supply with a high price, nor is it likely to ever be in that situation again.  The simple fact is that gas exploration companies know now how to use precision directional drilling (PDD) and hydraulic fracturing to good advantage, producing natural gas in surplus amounts.  The wholesale price is now under $2 per million Btu, due to PDD and hydraulic fracturing.   This is a world-wide practice, not limited to the US.   

So, then, what of the naysayers' claims that substituting wind, solar, and increased efficiency will replace the 2200 MW from Diablo Canyon?    Again, as above, the fact is that California added more than triple in solar MW compared to what was shut down at SONGS.  (7000 vs 2200 at SONGS).   The grid remains stable, blackouts did not occur.    

The wind resources in California are nearly fully exploited, as the state has only three economic locations for wind turbines at Altamont Pass, Tehachapi Pass, and Banning Pass near Palm Springs.   Any future capacity growth would be from retired wind turbine replacements with modern, more efficient turbines.   In addition, state-wide data shows that California's wind power plants have a lower-than-average utilization rate, or annual capacity factor compared to the states in the Great Plains region.  In good years, the wind provides approximately 26 percent capacity factor, and in poor years about 22 percent.   In contrast, the Great Plains states have capacity factors of 35 to 42 percent on an annual basis.  Using rough numbers, 40 for the Great Plains and 25 for California, a wind turbine would produce 60 percent more power in the Great Plains (40/25 = 1.6).   However, the costs to install and operate would be effectively the same.  It makes great sense to build wind turbines in the Great Plains but not in California.  

Increased solar power has some intriguing aspects that will be discussed next.   One major point (allegedly) in the Diablo Canyon shutdown agreement is that PG&E will procure 55 percent of its electricity from renewable sources.   This is 5 percent more than the 50 percent that state law mandates by the year 2030.    As wind power is not likely to increase much, the logical candidate is solar power.  The state has ample sunshine that presently produces approximately 8000 MW at noon (recent data from CAISO).   With a total annual power demand of 300,000 GWh, half by renewables then is 150,000 GWh.  Wind and other non-solar renewables in 2014 produced 34,000 GWh, leaving 116,000 GWh for solar to produce.   With the annual average capacity factor for California utility-scale solar of 26 percent (per EIA and California Energy Commission), the state would then require 51,000 MW of solar installed. 

And there lies the problem.  The solar arrays produce too much power for the grid to absorb on any given sunny day.  51,000 MW of solar output greatly exceeds the typical summer day's peak demand of 35,000 MW.   What, then, to do with all that mandated solar power?    One solution, already proposed and under consideration, is to store at least a portion of the solar energy output as hot oil, or molten salt, to be re-produced as electricity later at night.   Yet another is to increase the pumped storage hydroelectric capacity in the state, and store the energy by pumping water into elevated lakes.   A third solution is to store some of the excess solar energy in grid-scale batteries.   A fourth solution is to store some of the excess solar energy in gravity-based heavy rail storage systems, as the ARES system in Nevada will do when construction is complete.  

Update 1: 6/23/2016 -  More uses for excess electricity include a fifth solution - split water via electrolysis, store the hydrogen for later and produce electricity when needed via fuel cells; and sixth, have a multitude of electric vehicles on smart chargers to charge the batteries with excess power.   --- end update 1

It is an interesting time to live in California.  The last nuclear plant will close in less than a decade.  Solar power plants will be built in great numbers.  The electrical grid will not only survive, it will thrive.   Innovations and economics will, as always, combine to sort out the favored solutions to the various challenges that arise.   

Another article will discuss the expenses of keeping Diablo Canyon online, and why it makes economic sense to shut it down. 

Roger E. Sowell, Esq.
Marina del Rey, California
copyright (c) 2016 by Roger Sowell - all rights reserved







Monday, March 14, 2011

Reconsider Nuclear Power - Is It Ever Safe?


Below is the text of a post I made on nuclear power, from July 2009, titled "Nuclear Nuts." It seems appropriate to bring this to the fore, since the Japanese nuclear reactors have begun having serious problems. The pro-nuclear crowd is, for the most part, congratulating themselves over how well the Japanese nuclear reactors have held up, with only a few (six or eight or so) having any problems. Plus, they point out, it was not the March 11th earthquake that caused the problem but the giant tsunami that followed it.
I'm an engineer. I know what engineers can do, and I know their limitations. I'm also an attorney, with a law practice that deals with engineers and the myriad of issues that arise in engineering. I'll expand this post over the next few days as my time permits, but for now, the following observations.
First, no plant has ever been designed to withstand what natural forces can dish out. The earthquake in Japan was a 9.0, yet we have evidence of larger earthquakes occurring. The tsunami was 10 meters (30 feet, more or less), yet we have evidence of much, much larger tsunamis in the past. As but one example, there is a tsunami that will smash the entire US West coast from Hawaii, when a portion of the big island collapses into the sea. It is not a matter of IF, but a matter of WHEN. The tsunami will be hundreds of feet high. There are at least six nuclear power plants along the west coast, with four reactors right on the beach in California at San Onofre, and at Diablo Canyon. What Japan is dealing with now, California will be dealing with then.
Second, even the Japanese designs were not sufficient for the earthquake and tsunami that followed. The large initial quake was followed by many smaller aftershocks. It is also apparent that insufficient fuel was available for the Japanese reactors' emergency diesel generators, so even if they had generators that still worked, they would have been out of fuel.
Third, concrete containment structures may or may not maintain their integrity after a large earthquake and multiple aftershocks. It appears that the world is about to learn if the Japanese concrete containment has leaks or not, following the reactor core meltdowns.
Fourth, evacuating people in Japan involved a few hundred thousand people. For the San Onofre plant, which is near San Diego and suburbs of Los Angeles, there are likely millions of people who must be evacuated. That is a logistical problem of immense proportions.
Below, "Nuclear Nuts" addresses the question of nuclear plant safety. I did not include the safety and radiation release aspects of an earthquake plus a tsunami when I wrote that in 2009. Clearly, they are not safe when subjected to such stresses.
Another aspect of nuclear power plant safety must be mentioned. The plants are getting old, and things deteriorate, break, malfunction, and wear out with age. The Japanese are finding that old plants, (40 years old is one reactor with a melt-down), just don't work after an earthquake. The reactors in the USA are also from the 1970's and a few in the 1980s, so are also in the 40 year age bracket. Some are receiving extended operating licences for their third twenty-year period, meaning they will operate to age 60. This is a recipe for disaster.
Yet another aspect of a serious malfunction is a total loss of grid power, then the loss of cooling water, and having spent nuclear fuel stored on-site. The spent fuel also produces heat that must be removed by pumping water through a pool where the fuel is stored. When that water no longer circulates, the spent fuel also overheats.
-- Roger E. Sowell, Esq.
March 14, 2011 at 11:31 p.m. PDT
Marina del Rey, California
Nuclear Nuts, reproduced here and found on SLB here.
A few weeks ago [in June, 2009]I crossed the internet path of one internet nuclear advocate [the "gentleman" hereafter], a self-proclaimed “knowledgeable nuke” and one who fervently believes that nuclear energy is “safe, reliable, and affordable, a huge boon to mankind.” He is an advocate for very small nuclear power plants, with thousands to be built and located in city neighborhoods and industrial facilities.
Further, this gentleman states that nuclear power via atomic fission does not release any deadly materials in an uncontrolled fashion into the environment, unlike burning fossil fuels. [note: this is false, just ask the Japanese]
And last, the gentleman states that I am dead wrong when I stated that atomic energy is the most dangerous and toxic form of energy man has ever devised.
I have run across his type before: a true zealot, a true believer, and one who is not to be swayed by the force of any evidence supported by facts, as his mind is closed to any new or contrary information.
So, knowing in advance that this is a hopeless endeavor, that is, persuading the gentleman and others of similar ilk of the error of his beliefs, I press on, but only this one time. I have far too many things to accomplish in this life to waste more time arguing with one who will not listen to compelling arguments. Taking his assertions in order, “1) safe, 2) reliable, 3) affordable, and 4) a huge boon to mankind.”
Is nuclear power safe? As an attorney highly familiar with negligence and liability, both strict and otherwise, nothing is perfectly safe at all times. Safety is a matter of degree. Measuring sticks one can use to determine the level of safety include how many safeguards are required, how many injuries or deaths occur, and how the law views the matter. For example, driving a car may be considered safe. Yet a car (at least in the U.S.), must have quite a number of safety features before it is allowed to operate on the roads. These safety features include side impact doors, crash-absorbing bumpers, frame crumple zones, air-bags, seat belts, padded headrests and dashboards, the list goes on and on. In addition, there are laws for operating motor vehicles that are designed to increase safety, such as no talking on cell phones and no texting while driving, stopping required at red lights and stop signs, speed limits, operating the headlights at night, not driving while impaired by drugs or alcohol, and others. Yet thousands of people are killed or injured each month while driving. Even though driving a car kills people, driving is not considered an ultra-hazardous activity under the law.
An ultra-hazardous activity is defined under the law as “an activity that necessarily involves a risk of serious harm to the person, land or chattels of others which cannot be eliminated by the exercise of the utmost care, and is not a matter of common usage. Examples of ultra-hazardous activities include blasting, other uses of explosives, radioactive materials, and certain chemicals.
Nuclear power from fission uses radioactive elements, and is by definition an ultra-hazardous activity. The legal consequence of this is that no matter what happens, and no matter the contributory negligence of the plaintiff, the owner of the ultra-hazardous material is at fault when the plaintiff is harmed by the ultra-hazardous material or activity.
Next, safety can be measured by the amount of harmful material released into the environment, and the harm resulting from that material. Nuclear power plants have exploded (Chernobyl), have leaked radioactive water into the ground and streams (numerous times), and have sunk to the bottom of the sea in submarines, thereby poisoning the surrounding seas. The preparation of nuclear fuel leaves in its wake devastating damage to the environment, as for example the uranium mines in the U.S. Southwest. The Kerr-McGee plant that processed plutonium is another example of nuclear radioactive material that poisoned people, as the Karen Silkwood lawsuit clearly showed.
From the above, it can be seen that nuclear power is anything but safe. The industry makes claims to a safety record, but in reality the record is not yet written. Many thousands of tons of deadly radioactive waste material, as spent fuel rods, are stored in the more than 100 operating nuclear power plants in the U.S. These deadly radioactive wastes will likely be processed in one form or another someday, and the accidents, radiation burns, early deaths, radiation sicknesses, and long-term health consequences such as cancers from radiation have not yet occurred. But they will.
The removal from service and disassembly of many of the oldest nuclear power plants have also not occurred, with the attendant disposal of the radioactive portions of those plants. How many more radiation-related illnesses and premature deaths will occur at that time?
Further, nuclear fission that occurs in power plants produces the raw material for nuclear bombs: plutonium. No amount of denial by pro-nuclear forces can alter that fundamental physical fact. Also, the other, non-plutonium portion of spent nuclear fuel can be used to deadly effect in a dirty bomb, in which conventional explosives are wrapped in nuclear fuel and exploded. The resulting spread of toxic radioactivity is deadly to lifeforms. For those who deny that nuclear power plants produce bomb material, why is there so much angst in the world over some nations acquiring nuclear power plants, such as North Korea and Iran?

Point two, is nuclear power reliable? One must put the question in context, reliable in relation to what? If the comparison is to intermittent renewable energy sources such as wind, or solar, nuclear power is a bit more reliable. But compared to coal-fired plants, nuclear is no more reliable.Compared to gas-fired plants, it is no more reliable. And, compared to load-following gas-fired plants, it is less reliable. No utility can place a phone call to the nuclear plant on its grid during a peak power situation and ask the operators to crank it up another 20 percent for the next few hours, but a gas-fired plant can easily do that. No nuclear plant can be brought from a cold condition to full generating power within an hour, as can a gas-fired peaker power plant. The nuclear plant is designed to run at a steady output, and no other. Furthermore, the Nuclear Regulatory Commission can, and does, order nuclear power plants to cut back production or shut down entirely for various reasons. This certainly adversely affects the reliability.
Third, is nuclear power affordable? Many experts thought so in the 1970’s, but few would agree today. In fact, with a 2008 / 2009 cost estimate of $17 to 20 billion for a 2200 MW twin-reactor plant, nuclear power is one of the most expensive options around. That cost estimate was made before the NRC issued a new ruling, that every new nuclear power plant in the U.S. must be designed and built to withstand the impact of a large commercial aircraft. That alone will increase the construction cost by another 10 percent or more. As Craig Severance, CPA, has written, to justify the enormous initial cost and long construction time, the sales price of nuclear-generated power from a new plant must be 25 to 30 cents per kwh. By my estimates, when the aircraft impact design features are included, that will likely be 30 to 35 cents per kwh. In stark contrast, power from a new gas-fired plant is around 12 cents, and from a new coal-fired plant 9 to 10 cents.
Also under the subject of affordability, the gentleman claims that U.S. states with the highest nuclear power generation have the lowest costs of electricity. He cites the southeastern states for this proposition. The opposite turns out to be the case. In all modesty, I took a look at published, reputable data from the U.S. Energy Information Agency, EIA. From my engineering days, I have simple yet adequate skills in plotting data points on a graph, and determining the coordinates of the best-fit linear trend line through those points (see Figure 1 below). In all fairness, developing a trend-line is rather easy these days, when one uses a commercial spreadsheet such as Microsoft’s Excel™.The trend-line shows a positive slope, indicating that power price increases as the percentage of nuclear power generation increases in a state. The data showed that 31 U.S. states have nuclear power plants, with the lowest percent of total generation in Ohio at 6 percent, and the highest in Vermont at 70 percent. Interestingly, the average price for residential retail power in Ohio was 9.5 cents, and in Vermont was 48 percent higher, at 14.1 cents per kwh, in 2007. Connecticut was the highest of all, at 19.1 cents per kwh. The slope of the trend line shows a 0.75 percent increase in power price for a 1 percent increase in nuclear power generation in the state. For a 15 percent increase in nuclear power, the average power price will increase a bit more than 0.9 cents per kwh, or roughly 10 percent of the 2007 price nationwide. For those who advocate increasing nuclear power up to the level achieved by France, 80 percent, this chart clearly shows that would increase the average power price in the USA by 40 percent.
Yet, this data for 2007 uses power produced from mostly aged, nearly-paid-for nuclear power plants.New nuclear plants would, as shown above, require much higher power prices and would increase the cost of power to customers by much more.


Figure 1.
Power price increases 0.63 cents per kwh
for each 10 percent increase in nuclear power

This brings me to the gross unfairness of nuclear power on electricity prices. The poor and those on fixed incomes suffer the most from high power prices, as they have few options but to pay the price or do without. This is dangerous to health and safety in extreme heat and extreme cold.
Fourth and finally, is nuclear power a huge boon to mankind? Given the above, that nuclear power is by definition ultra-hazardous, produces vast quantities of toxic, radioactive wastes that can be used to manufacture nuclear bombs and dirty bombs, is not reliable due to mandatory power reductions or shutdowns, and is one of the most expensive forms of power on the planet that causes grossly disparate effects on the poor and those on fixed incomes (the elderly), the answer must be an emphatic and resounding NO.
The only thing positive about a nuclear power plant is the fuel is cheap. But, there are energy sources that are cheaper still. Four of those energy sources are solar, wind, wave, and ocean current.A fifth is geothermal, but it is very limited. Yet a sixth is hydroelectric, but there is virtually no possibility of increase. The natural resources of those first four power sources are enormous, and have scarcely been tapped to date. Each has features to recommend it, and each has certain drawbacks. But the drawbacks to not include the use of ultra-hazardous materials, do not include generation of deadly toxic wastes that endure for decades or centuries, and do not include power sales prices at 35 cents per kwh or more. Even the reliability issue is minor and getting smaller with new developments. Innovative and cost-effective storage systems are under development and testing in the national laboratories for wind, wave, and solar, which will forever make moot the reliability issue. Ocean current will not require energy storage systems, as the ocean currents flow no matter what is happening in the environment around them.
In conclusion, the propositions that nuclear energy is safe, reliable, affordable, a huge boon to mankind, and releases no toxics to the environment are clearly wrong. The facts clearly show this. No amount of dreaming or wishing or hoping by the gentleman or anyone else with similar opinions will change that.
UPDATE 1 (Nov 4, 2009): After several months and many comments, it is instructive to compare my assertions and facts to the beliefs stated by some of the commenters. First, much more natural gas has been found, just as I said. So much so that gas storage in the U.S. is completely full, and gas prices are very low. So much so that wind power projects are at a reduced rate because wind power generally replaces gas-fired power. Europe is drilling for and finding gas in their shale deposits, especially in Poland. New LNG import terminals are being delayed due to the vast amount of natural gas now available in the US. No need to import it if we can open a valve on land.
On the nuclear power plant front, South Texas Nuclear Project's proposed expansion is on the ropes - due to cost. This is just as I predicted. The cost estimate was $13 billion, and just recently was increased to $17 billion. The City of San Antonio is rethinking their involvement, and postponing their decision. How could such a thing happen, since nuclear proponents insist (indeed, shout it out loud) that such plants are proven technology with well-known cost estimates?
A second major event rocked the new nuclear power plant world this week, as the Areva company (the French vendor for the Finnish plant under construction) has just received a slap across the face for inadequate safety systems. The design must be revised to satisfy the nuclear regulatory agencies from France, Finland, and U.K. How could that be, since we are equally assured by the nuclear proponents that such plants' designs are safe? One would think that the design as approved was truly safe. Apparently not.
And a further point on the cost increase to withstand an impact from a large commercial aircraft. Some commenters stated that all 103 of the US plants already meet that safety standard. This is not true. The new safety standard applies to more than just the reactor dome, it also applies to the cooling system, and spent fuel storage.
It is also increasingly apparent, after a very cool summer and early killing frost, increasing polar ice at both poles, and almost zero hurricanes in the Atlantic, that CO2 has nothing to do with the earth's temperature. If the IPCC and AGW alarmists were correct, the increased CO2 (from 350 all the way up to 388 ppm) should have roasted the earth already. We should already have islands underwater (where are they?), seaports and seashores disappearing (where are they?), an early Spring and late Fall (not in the northern hemisphere, nor the southern), many more hurricanes (did not happen), and Arctic ice almost gone (it is increasing back to the 2005 level). [end update 1]