Understanding Nuclear Power Plant Risk

Mark Caruso
Senior Risk Analyst
Office of New Reactors

When it comes to the safety of using nuclear power to generate electricity, the NRC mission is protecting people from health risks by licensing and regulating nuclear power plant design and operation. In a perfect world there would be no risk at all. In the real world, we focus on managing and reducing risk below its already very low levels.

bikeridingFor instance, you can reduce the risk of a bicycle accident by ensuring you have working brakes and reflectors/lights. Wearing a helmet and leaving your headphones in a pocket while riding also reduce risk, but wrapping yourself in bubble wrap is probably going too far!

We all understand things in our lives that we consider “risks,” like riding a bicycle, by looking at how severe a bad outcome is and how likely that outcome is. The NRC asks three questions when considering risk:

  1. What can go wrong?
  2. How likely is it to go wrong?
  3. What are the consequences?

These three questions are called the risk triplet. Let’s apply the risk triplet to lifting a piano. What can go wrong? A crane could drop the piano while lifting it to a building’s upper floors. How likely is a piano drop? Since crane workers take lots of precautions that’s very unlikely. What could a falling piano do? If the piano did fall and you were unlucky enough to be underneath it…you can imagine the consequences! This event has a low likelihood and a high consequence. There are also high likelihood/low consequence events and high likelihood/high consequence events.

The NRC’s risk-management effort starts by identifying and eliminating high likelihood/high consequence events at U.S. nuclear power plants before moving to less-likely events.

Engineers use a method called probabilistic risk assessment (PRA) when analyzing risk at nuclear power plants. These assessments use engineering and math to find the answers to the risk triplet questions and create tools called the event tree and the fault tree. These trees map out possible ways and likelihoods of reaching a desirable or undesirable outcome in an organized way. Engineers use these maps to understand and manage nuclear power plant risk. An event tree starts with a trigger (initiating) event and then tracks the different possible resulting events that either reach or prevent an undesirable outcome.

In the sample PRA below, a skydiver jumping from a plane is the initiating event. The event tree follows what could normally occur next and then considers what happens if those events succeed or fail. For example, these events include attempting to deploy the main and reserve parachutes  

The desirable outcome occurs if either parachute opens successfully. The undesirable outcome occurs if both chutes fail to open. Since a skydiver would not normally start with the reserve parachute, this event tree contains three event sequences:

  1. Main parachute opens — desirable outcome
  2. Main parachute fails, reserve parachute opens — desirable outcome
  3. Both parachutes fail to open — undesirable outcome

Fault trees help determine a percentage between zero (outcome never occurs) and one hundred (outcome always occurs) for the outcome of each event sequence in the tree.

faulttreeA fault tree shows all the combinations of things that must go wrong to “fail” an event in an event tree. The diagram shows the ways a reserve parachute can fail to open. Think of a fault tree as a sort of family tree. Rectangles represent either “parent” or “child” events and circles represent pure “child” events. The “and” symbol between parent and child events indicates all child events must occur for their parent event to occur. The “or” symbol indicates any child event can cause their parent event. Engineers use the tree to identify the different combinations of child events leading to the event at the top of the tree. Historical parachute performance data helps provide a numerical value for the likelihood of each pure child event (e.g., dead battery). A mathematical formula combines individual event likelihoods to provide the numerical value of the likelihood of each combination of child events.

Event trees and fault trees are two basic parts of risk assessment, just like the brakes and gas pedal are basic parts of a car. In the same way all the other parts under the hood make the car work, risk assessments have lots of other moving parts that we could discuss in the future. The bottom line, however, is that risk assessments help the NRC and nuclear power plant engineers properly reduce already very small health risks, resulting in safely produced electricity at nuclear power plants.

Author: Moderator

Public Affairs Officer for the U.S. Nuclear Regulatory Commission

31 thoughts on “Understanding Nuclear Power Plant Risk”

  1. In my opinion, Nuclear power plan is all time harm for human, animal, and environment.

  2. The NRC’s Office of Nuclear Regulatory Research carries out the Accident Sequence Precursor program. This program examines real-world events at U.S. nuclear power plants to identify, document, and rank the events’ potential to affect plant safety. The Office of Research sends the Commission an annual paper on the latest program findings. Searching for “precursor” on each year’s listing http://www.nrc.gov/reading-rm/doc-collections/commission/secys/ will provide that year’s paper. The most recent paper includes discussion of Pilgrim’s 2013 shutdown during a severe winter storm: http://www.nrc.gov/reading-rm/doc-collections/commission/secys/2014/2014-0107scy.pdf

    The NRC website also has an earlier report on the program from the year 2000: http://www.nrc.gov/reading-rm/doc-collections/nuregs/contract/cr4674/

    Scott Burnell

  3. The problem with your approaches “what can go wrong” and “how likely is it” is that you can never know every accident “path”, i.e. all the things that could lead to a fatal accident. You can make educated guesses. You can maybe guess 99% right (although there is no way of determining that percentage). Proof: all really bad accidents so far have not adhered to the “pathways” the were “pre-ordained” by the nuclear priesthood of safety engineers. Their phantasy was either still too limited and/or the nuclear power stations might not have conformed to specifications. The “likelihood” is also not determinable under today’s circumstances. To do that you would have to know the failure rates (e.g. MTTF) of all components in a given accident path. However, unlike with automobiles with their hundreds of thousands of years of component usage and their crash tests, most nuclear power stations are singular events with idiosyncratic builds. Every mathematician/statistician knows that all you can “calculate under such circumstances is something as nonsensical as “fails once every million years – plus or minus ten million years” … And again: all known accidents have not conformed in any way to any pre-calculated probabilities. Q.e.d.

  5. Good info as usual from mjd. Although I admit I am a novice when it comes to the mechanics or usefulness of a PRA or fault-tree analysis, I would think that looking at an actual accident would be helpful in assessing the accuracy of the many assumptions made with regard to operator actions and equipment performance. I have looked at these analyses for plant events and there are a number of numbers that are plugged into the analyses. How do we know these assumed numbers closely reflect real conditions? If not a PRA how about the fault tree analysis showing the daisy-chain of actions (proper and improper) that lead to the accident? Seems at a minimum this would be a valuable training tool and would support the case studies on TMI and Chernobyl (and hopefully soon for Fukushima) that have been developed by INPO.

  6. Consequences over exaggerated?
    Published Date: 02/24/2015
    Detention Without Physical Examination of Products from Japan Due to
    Radionuclide Contamination
    Added to the list:
    For milk, filled milk, *** and milk-based infant formula, *** from the affected prefectures of Fukushima, ***Iwate, Miyagi and Gunma*** and Tochigi in Japan:

    “The article is subject to refusal of admission pursuant to Section 801(a)(3) in that it appears to contain a radionuclide, a poisonous or deleterious substance which may render it injurious to health. �[Adulteration, Section 402(a)(1)]”
    OASIS Charge Code: RADIONUC

    AND, for the listed products from the indicated prefectures:

    AOMORI PREFECTURE:

    Wild Mushrooms

    CHIBA PREFECTURE:

    Shitake mushrooms;
    Bamboo shoots;

    Common Carp;
    Sliver Crucian Carp
    ***Eel***

    Boar

    FUKUSHIMA PREFECTURE:

    ***Raw*** Milk;

    Wild Aralia Sprout;
    Azuki Bean;
    Bamboo Shoot;
    Non-head type leafy vegetables (i.e. turnip), flower head brassicas (i.e. broccoli and cauliflower);
    Head type leafy vegetables (i.e. Spinach, Lettuce, Celery, Cress, Endive, Escarole, Chard, and Collards);
    Chestnuts;
    *** ***
    Wild Japanese Butterbur Scrape;
    Japanese Royal Fern;
    Kiwi Fruit;
    Koshiabura (wild tree sprout);
    Log-grown Shitake mushrooms;
    Log-grown Pholiota Nameko (outdoor cultivation)
    Mushroom;
    Ostrich Fern;
    Pteridium Aquilinum (bracken fern);
    Rice;
    Soybean;
    ***Turnips***
    Ume;
    Giant Butterbur;

    Uwabamisou;
    Yuzu Fruit;

    Alaska Pollock;
    Ayu(excluding farm raised);
    Barfin Flounder;
    Black cow-tongue;
    Black rockfish;
    ***Brass blotched rockfish;***
    Brown hakeling;
    Salmon (landlocked) (excluding farm raised);
    Common Carp(excluding farm raised);
    Conger Eel;
    *** ***
    Fat Greenling;
    Flathead;
    *** ***
    Fox Jacopever;
    Goldeye rockfish;
    *** ***
    Black Porgy;
    Dace;
    Eel;
    Sandlance (excluding juvenile);
    Seabass;
    *** ***
    Long Shanny;
    Marbled Flounder;
    Nibe Croaker;
    Ocellate Spot Skate;
    Olive Flounder;
    Pacific Cod;
    Panther Puffer;
    Poacher;
    Red Tongue Sole;
    Ridged-eye Flounder;
    Rockfish (Sebastes cheni);
    ***Scorpion Fish***
    Sea Raven;
    Shotted Halibut;
    Slime Flounder;
    Spotted Halibut;
    *** ***
    Starry Flounder;
    Stone Flounder;
    Surfperch;
    Venus Clam;
    Vermiculated Puffer;
    Whitespotted Char(excluding farm raised);

    Bear meat;
    Beef;
    Boar;
    Cooper Pheasant;
    Green Pheasant;
    Hare Meat;
    Spot-Billed Duck

    GUMNA PREFECTURE:

    Wild Mushrooms;

    Salmon (landlocked) (excluding farm raised);
    Whitespotted Char (excluding farm raised);

    Bear meat;
    Boar;
    Copper Pheasant;
    Venison;

    IBARAKI PREFECTURE:

    Log-grown Shitake mushrooms;
    *** ***
    Bamboo shoots;
    Koshiabura (wild tree sprout);

    Seabass;
    Eel;
    Rockfish;
    *** ***
    Ocellate Spot Skate;
    Channel Catfish(excluding farm raised);
    *** ***
    Stone Flounder;
    Sliver Crucian Carp(excluding farm raised);

    Boar

    IWATE PREFECTURE:

    Bamboo shoots;
    Log-grown Brick-cap mushrooms (outdoor cultivation)
    Log-grown Shitake mushrooms;
    Log-grown Pholiota Nameko (outdoor cultivation)
    Wild Mushrooms;
    Wild Japanese parsley;
    *** ***
    Royal fern;
    Koshiabura (wild tree sprout);
    Pteridium aquilinum (bracken fern);
    Soybean;

    Dace;
    Black Porgy;
    Seabass;
    Whitespotted Char(excluding farm raised);

    Bear meat;
    Beef;
    Venison;
    Cooper Pheasant

    MIYAGI PREFECTURE:

    *** ***
    Royal Fern;
    Bamboo Shoots;
    Koshiabura (wild tree sprout);
    ***Wild Araila Sprout***
    Ostrich Ferns;
    Rice;
    Log-grown Shitake mushrooms(outdoor cultivation);
    Wild Mushrooms;
    Soybean;

    Ayu(excluding farm raised);
    Salmon (landlocked) (excluding farm raised);
    Black Porgy;
    Dace;
    Seabass;
    *** ****
    Whitespotted Char (excluding farm raised);

    Beef;
    Bear Meat;
    Boar meat

    NAGANO PREFECTURE:

    Wild Mushrooms
    *** Koshisabura***

    NIIGATA PREFECTURE:

    Bear Meat

    SAITAMA PREFECTURE:

    Wild Mushrooms

    SHIZUOKA PREFECTURE:

    Wild Mushrooms

    TOCHIGI PREFECTURE:

    Wild Aralai Sprouts;
    Bamboo Shoots;
    Chestnuts;
    Wild Japanese Peppers;
    Wild Royal Fern;
    Koshiabura (wild tree sprout);
    Wild Pteridium aquilinum (bracken fern);
    Wild Ostrich Ferns;
    Log-grown Brick-cap mushrooms (outdoor cultivation)
    Log-grown Shitake mushrooms;
    Log-grown Pholiota Nameko (outdoor cultivation)
    Wild Mushrooms;

    Whitespotted Char (excluding farm raised);

    Beef;
    Boar meat;
    Venison

    YAMAGATA PREFECTURE:

    Bear Meat

    YAMANASHI PREFECTURE:

    Wild Mushrooms
    http://www.accessdata.fda.gov/cms_ia/importalert_621.html

  7. Thanks for providing this information. But take a look at this article…http://www.japantoday.com/category/national/view/post-tsunami-deaths-due-to-stress-illness-outnumber-disaster-toll-in-fukushima
    The tsunami and the nuclear plant accident displaced thousands. I am sure it is hard to separate evacuation casualties from the tsunami versus the Fukushima nuclear melt-downs but one thing is sure-many people died from not only being evacuated but from having to live in temporary shelters away from their homes for extended periods of time, with no end in sight. That is the legacy of nuclear plant accidents. After almost 30 years there is still a 20-mile radius exclusion zone around the Chernobyl reactor in the Ukraine. There is no telling how long Japanese citizens will be kept from their homes in Japan.
    Please read the article. It is just heart-breaking how it has affected especially those folks who are most vulnerable. Nuclear power needs to be phased out ASAP. Too many people in this country live in the backyard of our nuclear plants. Literally millions of people in NYC, Boston, and Chicago live close to nuclear plants just to name a few. Even a false alarm at these plants will kill folks due to the resulting panic and voluntary evacuation. Just not worth it period!!

  8. Moderator Note:

    According to the Japanese government’s Nuclear Accident Independent Investigation Commission http://warp.da.ndl.go.jp/info:ndljp/pid/3856371/naiic.go.jp/en/report/ , “Approximately 150,000 people were evacuated in response to the accident” (page 15 of the report) “approximately 850 patients were hospitalized … Among these patients, approximately 400 were seriously ill, who either had serious medical conditions, such as those requiring regular artificial dialysis or the regular suction removal of phlegm, or were bedridden … at least 60 people died in the seven hospitals and in long-term care health facilities by the end of March 2011.” (pages 319-320 of the report)

  9. Turnages, thank you for the video. I don’t always make the time to watch meetings that are taking place in other states.
    No I wasn’t there and disrupting meetings isn’t my style….well at least not yet.
    I can understand why citizens, specially ones living next to these ticking time bombs are completely frustrated with the system.
    One thing is certain:The danger that nuclear energy presents is resonating across the world.

  10. Plus Turd over 1000 Japanese have died just going through the scary evacuation process. But Turd they are mainly senior citizens and handicapped folks.

    Moderator Note: Some verbiage removed to adhere to comment guidelines.

  11. Fukushima consequences were greatly over exaggerated?
    Turd, your remark is outrageous and unconscionable.

    This catastrophic nuclear accident has, still is and will continue to cause human, animal and environmental harm/damage/suffering.

    There is no end in sight!

    300 + tons of radioactive water have been entering the Pacific everyday for almost 4 YEARS, not counting the thousands of storage tanks on site holding the radioactive water that they keep pumping from the destroyed reactors.(I’m assuming you are of the mind set to just dump it in the ocean)
    And what to do with three corimus?

    TEPCO has not been able to effectively deal with an increasing amount of contaminated water, used to cool the crippled reactors and molten fuels inside them and kept in large storage tanks on the plant’s vast campus.

    Adding to TEPCO’s headaches has been the persistent flow of groundwater from nearby mountains travelling under the contaminated plant before washing to the Pacific Ocean.

    The International Atomic Energy Agency recently said TEPCO has made “significant progress” in cleaning up the plant, but suggested that Japan should consider ways to discharge treated waste water into the sea as a relatively safer way to deal with the radioactive water crisis.
    http://www.msn.com/en-us/news/world/fresh-nuclear-leak-detected-at-fukushima-plant/ar-BBhQtos

  13. Regarding public perception of NRC and others allowable risk management, when we see a NPP built on a shore that has been hit with higher tsunamis then the safety wall to protect it, makes one question what is the acceptable risks allowed. We find out after Fukushima what risks they allow, using non submersible pumps that failed (Saving Money), under sized battery backup on many sites(Saving Money), we see a NPP that uses a inner tube to stop a flood from a river!!! There are NPP down stream from dams that are questionable with foundation problems. We see the fuel pools filled to the max taking more risk if a quake hits. We see barrels of nuclear waste at the bottom of oceans and waste draining into the oceans. We have seen 6 NPP’s fail badly and the risk because of age increasing. We see how vulnerable these plants are to attack and some are now in a war zone. I’ll quit here but there is much more. How can the public believe that NRC is handling risk properly or is it to complicated.

  14. There you go again. The outcomes is not infinitely negative as you erroneously state unless you believe we are all doomed. The analysts and professionals at NRC are fulfilling their mission just fine.

    Moderator Note: Some verbiage removed to adhere to the comment guidelines

  15. What do you know about risk? More people have fallen to their deaths installing/maintaining home rooftop solar than working in nuclear. Having met the late great Norm Rasmussen, which BTW came when I was in my formative years, he instilled in me that risk equals the product of consequences multiplied by likelihoods. You seem to overestimate both by a very wide margin. Fukushima consequences were greatly over exaggerated and the likelihood of the planets aligning to produce the initiating conditions are beyond incredible.

  16. PPB, There is nothing to be gained from running a PRA on an actual event, if it even could be done, given the event has happened already. If it has happened, what can the probability calc tell you after it has happened? A PRA establishes the “probability” of one event relative to another, constrained by the input assumptions. Its usefulness therefore lies in comparison; the more likely one event compared to another, and the consequences, it can be a tool used to help decide where the best use of limited resources can be used for maximum gain. Mr Caruso also either doesn’t understand PRA or he oversimplified the example for a public forum, as wearing a helmet on a bicycle can do absolutely nothing to reduce the likely-hood of a bike accident; it may in fact reduce the consequences (head injury), but it can not affect the probability except possibly in a negative way. That helmet may actually increase the risk of the bike accident if wearing it reduces your situational awareness. It is all in the assumptions. I am a retired operator, so I understand PRA is a fantasy world tool having limits in the real world. It can be useful, but like all tools it can be harmful. My methodology is much simpler. I give it all 50/50, it will happen or it won’t, and if it happens to me it will be on midnight shift, first night of shift rotation when my situational awareness may be lowered. Also for the record, DBNPP did not have a precursor accident, we had a transient (I know, I was the Shift Supervisor). I agree your conclusion that TMI2 was 100% preventable is correct as in “what was the Root Cause”, however it has nothing to do with PRA. It has to do with an organization that is truly mature can admit its own mistake and take responsibility for it.

  17. I just read all the comments in this thread, and they are all intelligent ones from intelligent people. I find it a supreme pity that the NRC (which doesn’t know what it doesn’t know and all the things it is refusing to know) will not take them seriously. They will be relegated to the dust bin. The NRC has its mind made up; it is composed of “true believers” and it is no use confronting “true believers” with facts. The only slight chance we had for salutary change was Gregory Jascko (sp?.), but he was forced out. What you have left are the regular yes men and nuclear enthusiasts we’ve had since the days of the AEC and Lewis Strauss. We learn nothing because we’re incapable of learning.

  18. Your Wikipedia link sums up the arrogant attitude of some “experts” “The problem, from the perspectives of the experts, was a difference between scientific facts and an exaggerated public perception of the dangers”

    TMI,Chernobyl and the ongoing 3 core meltdown in Fukushima are NOT just perceptions, but are lessons learned/FACTS.

    What must be recognized, is there is a growing number of citizens that are informed.
    We attend the meetings, read the documents and have colleagues that are engineers.
    .
    And when it comes to a worse case scenario, the industry doesn’t have what it takes and that’s NOT just a perception either:

    A top American government nuclear expert – William D. Magwood – told the U.S. Senate Committee on Environment and Public Works:(re:Fukushima) 9/12/12

    It is very difficult to overstate how difficult the work is going to be at that site. There will need to be new technologies and new methodologies created to be able to enable them to clean the site up and some of these technologies don’t exist yet, so there’s a long way to go with that …. There’s a long, long way to go.

    Plus the nuclear industry has had over 1/2 century to figure out what to do with their waste and there’s still no real solution.

  19. Rather than trying to control something that is not controllable, wouldn’t it be easier to shut down all existing power generating nuke reactors and not build anymore? I the know the nuke industry supports a low percentage of job creation at a monetary loss which is in turn is paid for by the population as an exercise in a socialist agenda, so why continue a losing unneeded governmental misadventure? The dilemma of safe storage of wasted spent nuke fuel will continue for hundreds of years (not to mention thousands of tons of plutonium) because of a government agenda. Must be a reason they stopped above ground nuke bomb testing. Nuke power generating reactors are nuke bomb fallout in slow motion. Why? Because the background levels of radiation, traceable to nuke reactors, continues to rise after nuke bomb testing has ceased. What a waste of time, energy, money and resources. Take 10 years to build a nuke plant, run it for 40 years if you are lucky, take another 60 years to decommission it (hide the radioactive parts underground)…genius, for letting the taxpayers foot the long term costs and related health issues.

  21. If the outcome of an event is infinitely negative, then no matter how small the risk, the expected value is infinitely negative. Accepting an infinitely negative expected value is nothing short of reckless insanity

    Example: destruction of humane genome is infinitely negative, there no amount of nuclear power can be allowed.

    Example: Carrington event causes 150 nuclear plants to melt down, Acute toxic poisoning of the planet and elimination of almost all life within 5 years, therefore no amount of nuclear power can be allowed.

  22. Interesting to have this post on risk, just after Pilgrim was one step away from releasing massive radiation after a “snow storm”

    Pilgrim was very close to being forced to directly vent radioactive steam into the environment / neighborhood. They used every last line of defense they had, including dumping radioactive steam into the old BWR Torus aka Surge Tank.

    Even then the heat in the surge tank got so high, they had to use an emergency heat exchanger to cool the surge tank. Fortunately it worked. If that last piece of equipment had failed it would have been a serious accident with radiation exposure to the public.

    Pilgrim had the same types of equipment problems in the last 2 years, and FAILED to fix them, and the NRC failed on adequate follow up.

    http://nukeprofessional.blogspot.com/2015/02/pilgrim-nuclear-in-boston-came-very.html

  23. The comments I have seen so far seem only to support negative conclusions. Nonsence, the examples cited fail to support the idea Nuclear Power is too dangerous to be used. The records show that in most cases it is human error that is the root, in management and application in the use of these reactor facilities.

  24. ENC COMMENT: The article totally misses an important point. We have known since the 1960s that PUBLIC PERCEPTION OF RISK is not limited to the mathematical/engineering definition of risk , but includes a psychological component originally lumped together as “dread”. So long as the public is allowed to interact in licensing decisions, this must be recognized..,
    I refer you to http://en.wikipedia.org/wiki/Risk_perception article on Risk Perception.

  25. Very informative. Now how about providing an actual PRA and an actual fault tree involving an actual event at a nuclear power plant (NPP)?! How about using the Pilgrim NPP loss of offsite power events as an example? Losing offsite power at Pilgrim (located in the backyard of Boston) is, unfortunately, not a rare occurrence, it has happened around 20 times since the plant came on line. It is almost a routine event at the plant. Two total loss of offsite power events occurred at Pilgrim a couple of years ago (back to back) and earlier this year a partial loss of offsite power occurred. Please provide the NRC’s PRA and fault tree analyses for these events. Also, to show a worst case example, please provide the PRA and fault tree analyses for the Three Mile Island (TMI) accident and the precursor accident at Davis Besse which occurred two years prior to the TMI accident. If the industry and the NRC has its act together back then the lessons learned from the Davis Besse near-miss would have prevented the TMI accident. Thanks for bringing up this important subject. I am looking forward to how this methodology works in the real world.

  26. I am not sure about how the nuclear risk calculations work. I assume if the risk of a melt down is 1 in a 1,000,000 per 50 year operation then if 512 plants are built the risk would double 10 time making the risk approximately 1 in 2000 for 50 year of operation of plants. What I am trying to point out is all the published risk I have seen are for one plant not an expected group of plants running at the same period of time. Is the above correct or is there a formula for multiple risks?

  27. Reblogged this on Niki.V.all.ways.My.way. and commented:
    I find risk assessment fascinating, especially with the issue is a nuclear power plant. Unfortunately, the basis for beginning risk assessment doesn’t include the underlying risks we are choosing to engage in just by continuing down the nuclear path.

  28. Two thoughts:
    (1) If the consequences of an accident are extremely large then no matter how small the probability of the accident occurring is inconsequential.
    (2) Garbage in, garbage out: In calculating risk if the assumptions and data put into the risk equation are “garbage” then what comes out of the analysis is “garbage” also.

  29. Some of this is tragic self-delusion, as it omits low-cost preventive measures, such as ex-vessel monitoring that could track water-level and other thermodynamic parameters in reactors and spent-fuel polls in order to terminate an impending accident before extensive meltdown (e.g. TMI and Fukushima)..

  30. “Engineers use a method called probabilistic risk assessment (PRA) when analyzing risk at nuclear power plants”
    We don’t need a PRA .in deciding to build a nuclear power plant on a known earthquake fault/zone. We just need to use common sense!
    And to make matters worse, is to think the NRC would even consider approving a brand new untested & unproven nuclear reactor to be built in a KNOWN active seismic zone.
    (North Anna 3 ~ Central Virginia Seismic Zone)
    The NRC’s mission statement should be changed from “Protecting People and the Environment” to
    “Protecting the Nuclear Industry at all costs”!

  31. Unfortunately, this article fails to make anyone feel confident the NRC is a viable oversight body for nuclear power.

    The assessment of risk does not include some real obvious problems like the fact we have, still, no #RealNuclearWasteConfidence, confirming that we have zero threshold of safety on a permanent level, because it doesn’t exist.

    That unknown factor, along with its threat of catastrophic deadly impact (still not fully assessed from other historic events for their long term impacts), which the author fails to even present, cannot and does not justify a “safe” label by any thinking person alive today. To do so is irresponsible as a human, parent, citizen, scientist, professional.

    Nuclear anything may not be considered safe any more than one could consider the space program as a “safe” one. #Fukushima taught us that.

    The disengenuineness and lack of candor reveals that the NRC is not listening to the Inspector General’s assessment of the Commission and its work.

    Given actual history and events, the detailing of “normal” safety precautions do little too reassure anyone that either industry or the NRC really takes safety seriously enough to protect our planet with an source of energy this great.

    This article is a bit insulting given the real risks and dangers of nuclear energy, even for us novices.

    #nuclearizedwater does NOT freeze. That risk isn’t even addressed. How are we supposed to take this article seriously?

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