Steam generators are an option, not a necessity

The US Nuclear Regulator Commission (NRC) recently posted a blog written by Kenneth Karwoski, Senior Advisor for Steam Generators that attempts to help people understand a little more about steam generators. The blog post was titled Where There’s Steam, There’s … a Steam Generator.

Aside: Many of my colleagues would immediately point to the title as misleading. Their professional experience includes plants that produce a large quantity of steam without using steam generators. End Aside.

Since Mr. Karwoski’s job is to be a senior advisor for steam generators at the NRC, I understand why he would make the following parochial statement:

Steam generators provide vital technical and safety functions at many U.S. nuclear power plants.

My direct experience with nuclear power plants is limited to those that include steam generators, but I am aware that my experience in the specialized application of using nuclear energy inside sealed submarines full of people breathing in the same limited air space where the reactor operates is not representative of the whole range of design options.

In the mid 1950s, a series of experimental reactors called BORAX-1, BORAX-II and BORAX-III were built at a facility in Idaho then known as the National Reactor Testing Station. Those reactors proved that the radioactivity that was introduced into the water used to cool light water reactors was low enough to allow the water to boil in direct contact with nuclear fuel rods, producing steam to turn turbines without the need for expensive heat exchangers.

Vallecitos Boiling Water Reactor

Vallecitos Boiling Water Reactor

GE followed up on those experiments with the Vallecitos Boiling Water Reactor and then developed a series of boiling water reactors that use primary coolant to directly drive steam turbines.

Boiling water reactors continue to be a safe and cost-effective design choice. They have the potential to be far more cost competitive than pressurized water reactors under regulatory regimes that impose radiation dose and dose rate rules that are based on actual, vice imaginary health effects.

It is in the full knowledge of the existence of boiling water reactors that I assert that classifying steam generator u-tubes as performing a “vital safety function” is an exaggeration. All heat exchangers should be built carefully. They are worth maintaining in order to keep the system functioning as designed. They are worth repairing if any of the heat exchange surfaces begins leaking and allowing mixing of fluids that the designers prefer to keep separate.

However, steam generators in light water reactors do not require perfection. Minor failures should be accepted and fixed; they should not result in a decision to destroy multibillion dollar assets under the false assertion that the failure is a “safety issue.” The decision to permanently shut down units 2 and 3 at San Onofre was roughly equivalent in scale to deciding to decommission an aircraft carrier due to a single tube leak in a steam condenser.

The first person to post a comment on the NRC blog about steam generators was CaptD, someone I have encountered in other forums. He tried to make the case that people should be terribly concerned about the leaking steam generators and should blame the decision makers at SCE for selecting an “unproven and radical design” instead of replacing steam generators that had proven to be less durable than desired (San Onofre’s original equipment stead generators lasted only 30 years) with identical pieces of equipment.

He called San Onofre a “nuclear near miss” and claimed that it should enter technological history as an “engineering debacle of epic proportions like the Tacoma Narrows Bridge.”

I had to respond to that false characterization, even though I believe that San Onofre’s closure was an economic debacle of epic proportions.

I completely disagree with CaptD.

What people really should be told is that the operators at San Onofre correctly shut down Unit 3 when they received an indication that there was a tiny leak in one of the tubes of the generator that turned out to be just 1/2 of the “very strict limits” that the NRC imposes to require a unit shut down.

The action was correct because tube leaks tend to grow rather rapidly, but they do not tend to spread to other tubes. The small diameter of each tube prevents leakage from ever getting very large, even in the case of a complete rupture. The nature of primary coolant in a reactor where fuel rod cladding is intact makes primary to secondary leakage more of a nuisance than a safety issue – after all, the coolant is almost pure water containing tiny quantities of radioactive material with half lives longer than a few seconds.

The most exposed person would have received a radiation dose of about 5.2E-5 millirem (5.2E-7 mSv) in a world where the average annual dose is about 300 millirem (3 mSv) from background radiation.

After inspecting and plugging damaged tubes, both units 2 and 3 should have been restarted, probably no later than March or April 2012. Everyone should remember that steam generators are only a design choice – 1/3 of all of the reactors in the US don’t even bother to try to separate primary from secondary water. Pressurized water reactors with isolated primary systems were the right choice for their initial application – producing power inside sealed submarines full of people.

I lay the blame for the destruction of 1500 jobs and the capacity to produce about 14 billion kilowatt-hours of emission free electricity every year solidly on overly conservative decision-making and political action designed to force California to burn more natural gas.

PS – I have been privy to communications from an intervenor with an unusual position. He has determined that it is worth his time to file legal paperwork to advocate for the interests of SCE rate payers and California air breathers to force SCE to publicly disclose the basis for its decision to destroy an asset paid for by consumers under traditional rate of return regulation. My intervenor friend is a lawyer with a rock solid case. This will be an interesting story to continue covering.

About Rod Adams

47 Responses to “Steam generators are an option, not a necessity”

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  1. Sam Hobbs says:

    Rod,

    It is not clear to me that adopting a different design for the steam generator WITHOUT going through a License Amendment Request was really appropriate under the current regulations. That was certainly a contributor to the issue and the regulatory aftermath (unfortunately leading to the decision for the shutdown). However, it appears to me that the decision to shutdown permanently was a mistake from a “diversity” of power sources point of view. In addition, though going through the LAR process would have been frustrating, it almost certainly would have been worth it.

    Just a thought or two from a long time licensing engineer (and one who does NOT have all the facts at this time, so also an opinion subject to change based on additional information as it emerges).

    Sam

    • donb says:

      Sam Hobbs wrote:
      It is not clear to me that adopting a different design for the steam generator WITHOUT going through a License Amendment Request was really appropriate under the current regulations.

      From what I have read, it seems that the conditions that caused the failure of the steam generator tubes were not anticipated during the design, though there are probably a number of “Monday morning quarterbacks” who might say otherwise.

      Had SCE gone through the extra expense and possible delay of a License Amendment Request, the steam generators would have failed anyway.

      I don’t know that the ultimate outcome would have been any different.

      • Sam Hobbs says:

        It is POSSIBLE that the additional scrutiny associated with an LAR would NOT have identified the problems; however, additional scrutiny and additional sets of eyes looking at a design and an issue very frequently do identify problems that had not been anticipated. Since it didn’t happen, we will never know. However, SCE is currently alleging in a complaint that the designer of the steam generators “failed to design tube support structures capable of withstanding the extreme thermal hydraulic conditions within the RSGs.” (http://atomicpowerreview.blogspot.com/2013/07/sce-serves-mitsubishi-with-formal.html)

  2. Rev. Mike says:

    Sam, I agree.

    Rod, shutting the plant down makes as much sense as it made to shut down Zion, which is to say, it didn’t. At that time, I, too, was working in Regulatory Affairs (i.e., Generic Licensing) and had license renewal, on the one hand, and decommissioning, on the other, as areas of responsibility. Working with accounting folks, I learned that these decisions essentially hinge on the assumed forward-going price of electricity. Since that’s anybody’s guess what that will be, one can justify any decision for renewal vs. decommissioning one wants as long as they can justify that assumption.

    Thus, these decisions are entirely political. With Zion, I believe Oliver Kingsley at ComEd had an intractable issue with the operators’ union and chose to deal with it in that manner. It’s not clear to me what SCE felt it was dealing with, but I suspect their management had simply had enough and wanted out. I think out decision at Duke to shutter Crystal River 3 was a bit more complicated by technical considerations and level of confidence in the final cost to repair the containment, hard to say since no one asked me :), but I think either choice could have been justified economically.

    • Sam Hobbs says:

      Rev. Mike, I do not reside near either San Onofre or Crystal River, but the economic consequences of shutting a plant down reflect into the community as well. As it turns out I visited the area near Crystal River recently and, at a barber shop (always a great place to hear about local concerns), there were several people there who were talking about how much they resented the decision to shut down Crystal River and how much it was going to hurt the local economy. Perhaps the community in the vicinity of San Onofre is less nuclear friendly, but the impact on their local economy will be present nonetheless.

  3. BobinPgh says:

    But Rod, there must be some reason why some utilities chose pressurized water reactors because then, why don’t we have all boiling water models? At this point, after Fukushima happened, would that not be a turn off if a utility wanted to buy a nuclear power plant now? It seems that they would stay away from GE reactors just as if you hear that their refrigerators were bad that a consumer would stay away from them. Who makes the decision about brand and type anyway? I never recieved a ballot in my electric bill. I read one advantage of the GE boiling water reactor is the ability to turn its output up and down like one would turn up a radio to meet demand, a feature they would need in Japan more than in the US. But the PWR design is all the way on or off.

    And Reverend MIke, as for San Onofre, I think SCE was just tired of doing the “songs and dance” over the repairs and having to wait for new steam generators that they just got fed up and quit.

    • gmax137 says:

      “turn its output up and down” — PWRs are certainly capable of load following. Don’t you think the submarine reactors do this? Nuclear plants (both BWRs and PWRs) are run at full power because they have the lowest fuel cost.

    • jmdesp says:

      I’ve heard the French point of view, it is that the security margin is better with PWRs.
      On one side there’s a concern about water that has been in direct contact with the fuel rods going outside of the containment building, not so much with the fact it’s too radioactive in normal use, but more that if for any reason something happens, and a rod starts to leak fission products, then the radiation goes directly outside the containment.
      But very likely the most strongly felt argument is about the possible risk of a pressure transient resulting in a dangerous power increase. I’m not sure the perception of that risk is really realistic, since looking for the correct translation of it in English, I just found out the way it’s been explained to me is the opposite of how it actually works (or then it’s my fault for not understanding correctly, but I really thought it was about too much steam and not too little).

      BTW recently when reading a document about the dismantlement of Chooz A, I found out that part of the heat exchangers tube have been harder to decontaminate, because during the plant operation period, they had been plugged after developing leaks.

      • James Greenidge says:

        Re: “On one side there’s a concern about water that has been in direct contact with the fuel rods going outside of the containment building, not so much with the fact it’s too radioactive in normal use, but more that if for any reason something happens, and a rod starts to leak fission products, then the radiation goes directly outside the containment.”

        I believe were the efficiency and relative simplicity of BWRs built underground that this major concern would’ve been rendered moot. A hole is also cheaper than a dome, IMHO (tho’ could be wrong…)

        James Greenidge
        Queens NY

        • Rod Adams says:

          @James

          I think the cost of digging deep holes and building underground would surprise you. I know it surprises me.

          • Bas says:

            Other consideration:
            – Such underground situation may spoil the ground water, which may stream towards … So the hole becomes quite large as it needs precautions against that.
            – Underground the force of the explosion cannot go away.

            However such underground reactor would be much more difficult to hit by terrorist (plane attack).

    • ddpalmer says:

      As a long time health physics technician I know that at a BWR the whole steam plant has low level contamination and thus requires contamination controls for all work. So the workers need to be trained as rad workers, more protective clothing will be used and more HP techs to cover the work. While at a PWR, unless there have been serious leaks, the steam plant work can be done without contamination controls.

      There are other issues, like a BWR is a simpler design with less equipment costs and BWRs are usually more efficient. I don’t know all the issues or which ones dominate in a given situation.

  4. Bas says:

    I understood that vibrations were the real cause of the leakage.

    That imply that:
    – simple repair, e.g. changing the leaking tubes, delivers only a temporary solution. One can wait for the next leakage (in a different tube) within a year or so.
    – continue despite the leakage is dangerous as the leakage itself may add extra vibration. If resonances, it may deliver very fast (explosion like) expansion of the leakage together with big new leakages (would not be the first time).

    All that would degrade SCE towards a cheat, since SCE stated explicit that it follows the highest safety standards.
    Such a ‘fraud’ contributes to a bad public climate regarding other NPP management/owners (not trustworthy).

    Btw.
    Chernobyl showed that even low levels of 0.5mSv/year extra NPP radiation generate already significant harm. Especially to the unborn and babies.
    That is mainly caused by (internalized) alpha particles.
    The ICRP model is based on the atomic bombs in Japan that generated almost only external gamma radiation.

    • John Englert says:

      Get your decimal points in the right place please.
      Here is a quote from the radiation safety page on the University of Pittsburgh website:

      the National Council on Radiation Protection and Measurement (NCRP) has recommended that the total dose equivalent to the embryo/fetus from occupational exposure of the expectant mother not exceed 500 mRem (NCRP Report No. 53), and that once the pregnancy is known, exposure of the embryo/fetus not exceed 50 mRem in any month (NCRP No. 91).

      • Bas says:

        @John
        I meant a half mSv/a (~50 mRem/a).

        The effect of low level Chernobyl fall-out measured in Germany (Bayern) was roughly 60% more still-birth, Down, congenital malformations per mSv.

        There is little doubt regarding that measurement due to ‘lucky’ circumstances:
        – Since 1980 Bayern population administrations kept detailed records of all birth, stillbirth, Down, congenital malformation (including the types), etc.
        Chernobyl occurred 1986.

        – The fall-out differed greatly between adjacent districts in Bayern (rainfall out of the Chernobyl cloud was local); The high radiation level districts had a level of ~37 Cs kBq/m2, the low level districts ~5 kBq/m2. (conversion rate from kBq/m2 Cs137 to mSv/a: 0.0143).

        – In districts with raised (Chernobyl caused) radiation levels, a sudden increase in stillbirth, etc. occurred. That did not occur in adjacent districts that got no fall-out.
        That increase continued in the years thereafter (Cesium137 involved)

        – The adjacent districts are similar in population backgrounds, pre-Chernobyl stillbirth.

        So the measurement was simple counting using the population administrations and then use standard statistical methods incl regression analysis.
        (~stillbirth rise in high radiation districts ~0.1% from ~0.3% towards 0.4%)

        Notes:
        – Deformities (skull, face, jawbone, neck, spinal column, etc) and congenital malformation of the heart showed similar increases.

        – This does not match with the ICRP model. But that model is based on external radiation, mainly gamma (effects of the atomic bombs on Japan and medical X-ray).
        How much a certain amount of radiation affects the embryo/fetus depends very much on whether it is internal or external.
        And part of Cs137 stays internal in your body forming ‘hot spots’.
        (ICRP representative has admitted that its model cannot be applied to post-accident situations; check the video half-way down the page).

        – IAEA/WHO studies regarding Chernobyl health effects have numerous weak points as shown by authors.

        – Some remark that then high level of background radiation should also have a negative effect. That is correct and shown, not only regarding more DNA damage, but also regarding premature death.

        • John Englert says:

          “This does not match with the ICRP model. But that model is based on external radiation, mainly gamma (effects of the atomic bombs on Japan and medical X-ray).”

          Where (or should I say when) have you been? Saying that dose related risk assessments are based mainly on A-bomb survivors is like saying that quantum mechanics is based mainly on the plum pudding model of the atom.

          • Bas says:

            @John
            Check the video in the link.
            Then you can hear that the ICRP representative admits it.

          • Rod Adams says:

            @Bas

            Let me get this straight. You want people to ignore the research and conclusions reached by the vast majority of the world’s experts on radiation health effects and instead take the word of a well-known and documented crackpot like Chris Busby?

            You have just about worn out your welcome here.

            You continue to spread lies that are completely illogical. Do you somehow believe that the doses documented in the case of radium dial watch painters were external only? Do you think that radon-related radiation is external whole body?

            Heck, watch the video that you linked to again and tell me that the ICRP representative “admits” that internal doses are more dangerous than their model shows. In my opinion he said quite the opposite; he indicated through both words and body language that he believes their model is conservative but includes uncertainty that might be 2-3 orders of magnitude. In other words, he believes that the uncertainty is likely to be in the direction of OVERESTIMATING risk, not underestimating it.

            Post your lies one more time and you will be invited find another microphone.

          • Bas says:

            Sorry Rod,
            I didn’t see Busby was the interviewer, went to the page and started the video, skipped the intro.

            Just checked the words of the ICRP member as he is the important man, and heard him declare about that their model could be orders of magnitude wrong.

            So I concluded that this ICRP member considers their model as not accurate for NPP accidents, to say it mildly…

            But agree, you are native English speaking and my native language is dutch.

          • Rod Adams says:

            @Bas

            I needed no introduction; Busby has worked hard to make sure that he is instantly recognizable. He has a unique way of speaking and dressing that includes a trademark hat.

            He must think it helps his marketing efforts.

            Again, the ICRP member agrees that his model has large uncertainties – IN THE CONSERVATIVE DIRECTION. It overestimates the risk by 2-5 orders of magnitude.

          • Bas says:

            It surprises me that this interviewer is the ‘infamous’ Bush. His cap together with his behavior (perhaps he sports a lot?), makes him look like a starting ‘naughty’ research journalist.

            The ICRP member statement is relevant to me as:

            – Also based on Chernobyl, the UN linked Codex Alimentarius Commission lowered the max. allowed radiation in food from 5mSv/a towards 1mSv/a, while infant food got even ~10times more strict limits regarding some radionuclides.

            These at least 5 times more strict guidelines seem at odds with an unchanged ICRP model. The idea that ‘greens’ took over the Codex is invalid. Others
            accuse IAEA and big food companies took over the Codec.

            note: Japan adopted the new guidelines. So now Japanese food forbidden because of to much radiation, may be exported to US (EU won’t accept that food).

            – Most studies regarding Chernobyl radiation show amounts of health damage at low radiation levels that do not fit with the ICRP model.

            While critics can be exerted for some studies, for other studies (such as the Bayern one, showing ~20 times more damage to unborn than LNT/ICRP predicts) that is not tenable while it has highly significant results.

            – While IAEA/WHO declare Chernobyl will have few thousand deaths, many other researchers come up with death figures that are magnitudes higher.

            And those researches declare their estimates to be based on many studies (such as the Bayern one) neglected by IAEA/WHO. The 2006 IAEA/WHO report considered only Ukraine/Belarus/Russia.while ~60% of fall-out was in W-Europe.

            IAEA/WHO refer to their own reports which are highly criticized as serious flawed at numerous points.

            Impact of radiation is also relevant to my children. Even regarding CT-scans as those seem to have also risk consequences.

            The statements of the ICRP member show that I should take his model not very serious in my search for the truth, but that it is far better to look for good quality studies yourself.

    • ddpalmer says:

      “Chernobyl showed that even low levels of 0.5mSv/year extra NPP radiation generate already significant harm. Especially to the unborn and babies.”

      Really? And how did it show that?

  5. Sean McKinnon says:

    Bas… please provide peer reviewed scientific studies that show a link to the Chernobyl steam explosion and “deformed babies” (hint: he can’t)

    BWR’s are just as safe as PWR’s the negative void coefficient in a BWR causes the fission reaction to shut down if there is a power excursion. I think people should judge technology in a fair light as I don’t believe any technology would have survived the extreme catastrophic natural disaster under the circumstances at the Fukushima diachi site. Imagine the contamination from fly ash slurry being spread by the tsunami if it was a coal plant, we already saw gas fires and explosions at other sites but no one is calling for shutting down all gas plants.

    • Bas says:

      @ddpalmer
      Please refer to my answer to John. Just above your post.

      @Sean
      Assume you mean (links to) studies that show negative reproduction effects regarding the Chernobyl reactor explosion:
      publication in the Lancet
      The Bayern study by the German radiation institute.
      European stillbirth proportions before and after the Chernobyl accident
      Perinatal mortality in Germany following the Chernobyl accident.

      • Sean McKinnon says:

        I don’t consider the Lancet to be a quality peer reviewed main stream scientific journal.

        Just because a certain statistic may have changes after the accident does not make a causality that it is because of the accident. That is like saying that before I started reading atomic insights my cholesterol levels were always normal, after I started reading atomic insights I went for a physical and my cholesterol levels are high. High cholesterol levels are linked to heart disease and death. Therefore, I have proven reading Atomic Insights causes heart disease and death!

        This may sound silly but this is exactly how many anti nuclear people make their connections.

        • Bas says:

          @Sean
          Do you then know a better research method that can proof those effects were caused by Chernobyl?

          As there is no such method, we have to do with the high probability that these effects were caused by Chernobyl as:
          1- They happened at the same time (period) in different districts in Bayern with high level (Cs137) radio-activity, in Berlin, Finland,.. and
          2- In Bayern those effects did not occur in districts where the radio-activity was small / same level as before Chernobyl.

          I cannot imagine any other possible cause that could create those two effects covering such a large area, at that same time.
          Agree with you that that does not imply that such a cause does not exist.

          Btw.
          The Lancet is in the medical research world considered to be one of the most prominent journals.

        • Brian Mays says:

          Let’s not forget that it was The Lancet that decided, in 1998, to publish the severely flawed study by Andrew Wakefield, which kicked off the crazy anti-vaccine/autism-link movement.

          The paper has since been retracted, and Andrew Wakefield’s reputation has been destroyed outside of certain conspiracy-theorist circles, but it just goes to show what kind of crap can make it into a formerly prominent “scientific” journal.

          The Lancet still has a high impact factor, but it has also earned a reputation in recent years for publishing absolute garbage. Considering that it has managed to protect its strong reputation, one has to wonder about the quality of science that is being conducted in these fields of research.

  6. Jim Rogers says:

    Rod,
    This may upset the PWR people, I was one for many years both in the Navy and commerical reactors, but from an operational aspect as well as accident mitigation a BWR is truly a “Better Water Reactor”. I say this based on my operational experience as well as having performed and evaluated the design analyses for both types of reactor plants over more than 40 years in the industry.

    I admit that the larger containment designs typically associated with PWRs are more forgiving in an Extended Loss of AC Power (ELAP), but for all current licensed events mitigation is very simple. Inject water and cool the torus. No high pressure issues and in the final analysis depressurization and use of low pressure injection systems mitigates the issue. Core uncovery can be accommodated to 2/3 core height and the multiple fill systems, i.e., HPCI, RCIC, Core Spray and LPCI (Type 3/4) are very simple and reliable. Later improvements in Type 5/6 with HPCS give more flexibility.

    Both types are vulnerable to ELAP with Mark I’s and II’s more vulnerable than Mark III’s . But ensure AC power and accident mitigation at a BWR is very straight forward.

    None of this is intended to demean or imply that the PWR design is deficient in any way. PWRs have proven highly reliable, in many cases much more so than BWRs likely do to easier access to secondary plant components. They are very capable of accident mitigation, including steam generator tube rupture (SGTR) a feature that seems to have been overlooked in the San Onofre disaster. It is a shame that 2200 MWe is now off the grid for an 85 gpd leak that the licensee promptly addressed. I suspect that the leadership of the NRC is more concerned with the political aspects of safety regulation than the technical aspects.

    • John ONeill says:

      Do you have a good source for a layman’s explanation of PWR / BWR differences? For example, does a BWR have to run on pure water with no boron, and does this mean you can’t get as high a burn-up, or can poisons in the fuel do the same job? And if a BWR runs at lower pressure, does that mean its heat to power efficiency is lower?

      • Paul W Primavera says:

        BWRs run on pure water with no boron. The two means of reactivity control for a BWR are recirc water flow control and rod control whereas for a PWR the two means of reactivity control are boric acid shim and rod control.

        In a BWR, boiling occurs in the core. As recirc flow is raised, more bubbles are swept away from the fuel, allowing more water which adds positive reactivity and thermalizes more neutrons which raise boiling back up. When recirc flow drops, more steam voids form in the core, which adds negative reactivity and doesn’t thermalize neutrons as well. Boiling goes back down.

        In a PWR, when you want to change power, you raise turbine load, then that lowers steam pressure out of the S/Gs which lowers steam temp which lowers RCS T-cold which thermalizes more neutrons which raises fission which makes T-hot rise which restores steam pressure.

        BWRs operate very differently. When you want to raise power, if you raise load on the turbine generator first, that will drop steam pressure which makes more voids in the core which drops fission by thermalizing less neutrons, which drops pressure more. So what you have to do is raise recirc flow first – “blow” more voids off the core to add positive reactivity. That raises fission and raises steam pressure. The governor control system on the turbine generator senses this and opens the throttles to control reactor pressure, and thus raises turbine generator load.

        PWRs also usually operate at a flat rod height. BWRs don’t because boiling and turbulence in the core introduce weird reactivity changes, so they operate with programmed rod patterns that get switched or alternated periodically for even fuel burnup and xenon distribution and all that sort of stuff.

        BWRs also have rods coming in the bottom and are controlled by hydraulic pistons, unlike PWRs with rods at the top with electric CRDMs. And BWRs do not have fine motion rod control. They move rods in steps, and they can only move one rod at a time, which makes for a very long startup. They have a Rod Worth Minimizer / Rod Block circuitry designed to prevent moving high reactivity rods at inappropriate times.

        New ABWR and ESBWR have fine motion rod control with electric motors, but coarse rod movement and scram are still hydraulic from the bottom. Also, ESBWR has natural circ flow – no recirc pumps. It uses variation in feedwater preheating on the 7th stage feedwater heater for reactivity control at power. And ABWR has internal recirc pumps inside the RPV, unlike most BWRs in the fleet which have external recirc pumps that provide driving head to internal jet pumps in the RPV.

        Note: B&W PWRs with their OTSGs, their slightly superheated steam to the HP turbine, and their Integrated Control Systems are themselves very different from Westinghouse and Navy sub PWRs. Both B&W PWRs and GE-H BWRs are very dependent on the plant process computer (and for BWRs, something that’s called 3D Monicore – I can’t get into all the details here).

        BTW, all this stuff is freely available in the public domain at the US NRC web site or the Virtual Nuclear Tourist or the IAEA web site or others.

  7. Paul W Primavera says:

    Please read this BWR training module course from the US NRC web site. It isn’t bad:

    http://www.nrc.gov/reading-rm/basic-ref/teachers/03.pdf

  8. George Carty says:

    I was confused when I read about BWRs in this article — I thought from the title that it was going to be promoting Brayton-cycle reactors!

  9. Paul W Primavera says:

    General Atomics has a great Gas Cooled Reactor Design that operates on the Brayton Cycle:

    http://www.ga.com/gt-mhr

    I don’t know what progress if any GA has been able to make with the US NRC. I suspect little to none.

    :-(

  10. Bill Chaffee says:

    According to SCE it would not be cost effective to restart San Onofre. Is that based on the assumption that natural gas will stay below a certain price? If so than what is that certain price? I would like to see that information made public.

    • Rod Adams says:

      @Bill Chafee

      If you read the letter from the intervenor that I posted, you will find that he is demanding a publicly accessible accounting of the numbers behind the decision by the company to destroy an asset that the ratepayers paid for and to saddle them with the expense of decommissioning without any access to twenty-thirty more years of electricity revenues to help reduce the cost per unit of electricity produced.

  11. Josh says:

    Rod, a great response. This CaptD person is a typical antinuke, he only knows what he reads, which is selective and highly quesionable to begin with. He and his quack supporters are neck deep in the FUD and cant get enough of it. I would also like to reiterate that I am tired of this Bas character’s trolling and would be in favour of a temporary ban should the same nonsense and qualitative garbage be repeated. I think, thus far, that you have been quite fair to him.

  12. Daniel says:

    Prime Minister Shinzo Abe has won the election yesterday in Japan. He is the only openly pro nuclear party and now controls both houses. He has power.

    Expect them nuclear plants to open sooner than later.

    Funny that all these anti nukes protestation do not win election at the municipal or state level in Japan since March 2011?

    The proof is in the pudding like they say in England.

    • Daniel says:

      Abe Did well in Fukudhima…..

    • EL says:

      Expect them nuclear plants to open sooner than later.

      Turnout was lowest since 1998.

      Nuclear critic in Yamaguchi Prefecture loses as predicted, but makes good showing “in a region considered to be a conservative stronghold.”

      I’m not sure what you mean that now they can move forward with nuclear. Has the “nuclear village” been dismantled in Japan or not? You seem to be suggesting politicians (and business interests) can still interfere with review and safety decisions at the new regulatory agency. If this is true, then not much has changed, and few lessons have been learned from Fukushima.

      The economic reforms put in place by Prime Minister (and party) are massive and transformative, and people wish to see them through. This is not surprising. In a way, Abe has declared war on the economic system of Japan, and at this point there is little turning back. Their currency has been devalued 20% in last six months, this is not good news for energy outlook (whether it’s new safety equipment for nuclear re-start, oil and gas imports, or renewables expansion). The Japanese have decided it’s time for radical break with the past, or to go bust trying. Renewables are just as much a part of their plan as nuclear (and if the Japanese people have a say, perhaps even more so).

      • Daniel says:

        EL,

        You are one of a kind. With the limited land that Japan has and with its capricious ‘hilly’ geography, renewables have been ruled out a long time ago on a big scale.

        Haven’t you heard of the massive land requirements of the unreliables ? Read up on that topic. Japan is a small country.

        Prime Minister Abe is pro nuclear. Since day one. Everyday. All day long. Everywhere. All the time. All other parties are against it.

        He won. Low turnout you say ? Though love. Where were zillions of them anti-nukes? I guess you only see them by the 100’s on the street and not in enough number at the voting booths.

        Abe’s wife is anti nuclear. Ain’t it cool ?

        • EL says:

          Haven’t you heard of the massive land requirements of the unreliables ? Read up on that topic. Japan is a small country.

          I have looked at it, and I don’t find this to be the case.

          “Japan’s energy consumption has been rated the highest in the world” (pg 4241).

          Not too hard to recommend where they should start.

          JREPP suggests 60% from renewable sources by 2050 is a reasonable target: “10 percent for wind power, 18 percent for solar energy, 14 percent for biomass, 10 percent for geothermal heat and 14 percent for hydraulic power.”

          http://www.japanfs.org/en/pages/028554.html

          Nuclear contributed 30% to their electricity demand prior to Fukushima. Given their island status (as you note) … suggesting they boost their energy security, affordability, and independence via renewables and also work on nuclear safety and reliability (for an economy the size of Japan) doesn’t sound too outrageous to me. You?

          • Daniel says:

            EL,

            Stop the non sense will you !

            Among developed nations, Japan is one of the countries with the lowest rate of food self-sufficiency. (Hint: Food grows on land)

            Do you think they can chew up additional land so that solar and wind and bio fuels and hydro can generate base load power?

            Please stop the madness. Common sense dictates that nuclear will prevail and endure.

          • quokka says:

            I would be surprised if Japan’s energy consumption was the “highest in the world”. Via Google, World Bank Data:

            Similar to Germany and the UK

          • EL says:

            @Daniel.

            What makes you think this has to do with land availability. According to Ministry of Agriculture, Forestry, and Fisheries, it has mostly to do with changing dietary habits, and lower cost of imported foods (via appreciation of the yen after 1985).

            http://web-japan.org/trends00/honbun/tj000604.html

            If you’d like to give me a link that suggests the contrary, I’d be happy to read it.

          • Manic says:

            @ EL

            From your 13 year old link: “The Ministry of Agriculture, Forestry, and Fisheries estimates that if this trend continues, the rate will fall to about 38% in fiscal 2010.”

            Well, I guess the trend did not change and Japan’s food self sufficiency, based on calorific intake, fell to 39% in 2010.

            http://www.japantimes.co.jp/news/2011/08/12/national/food-self-sufficiency-rate-fell-below-40-in-2010/#.UezKZI0wcW8

            I’ve always been a proponent of the natural division of labor. Japan has a huge population, living in a high tech economy, with very few natural resources, a harsh climate and tricky geography and geology; mountainous and earth quake prone.

            They shouldn’t bulldoze their forests, nor divert their already small food-crop production to fuel a bio-mass economy. Save the fuel, sell the bulldozers to Canada and Australia and bring some food back home to eat.

            But first things first: turn the nukes back on. 50 switch flicks for 45 GW of emission free electricity.

          • EL says:

            They shouldn’t bulldoze their forests, nor divert their already small food-crop production to fuel a bio-mass economy.

            Nobody is suggesting they do any of these things. Agricultural land is falling out of production in Japan, waste biomass is going unused, dietary preferences are changing, agricultural policy is stagnant, and rural famers are aging (and nobody is stepping in to fill these roles).

            The question is whether low self-sufficiency is being driven by land availability in Japan, or by other factors. And it appears to be driven by other factors (as suggested by nearly every study by Ministry of Agriculture, Forestry and Fisheries, who measures and documents these things). See one example here. Efforts to boost self-efficiency do not speak of resource constraints or land availability but rather crop selection, changing dietary habits, lack of structural reform in agriculture, trade policy, concerns over food safety, abandoned arable land, aging of farmers, lack of support services for rural residents (on relative basis), inadequate policy efforts to increase rural farmers and lifestyles, low production of feed crops, lack of “food education,” affordability of imports (via yen appreciation), etc.

            With arable (previously farmed) land being abandoned at a high rate, it doesn’t seem like land availability has much to do with anything. Even a 13 year old source suggests as much.

  13. Cyril R. says:

    Nuclear powerplants in the USA are specifically designed to cope with all sorts of accidents, including steam generator tube rupture, and up to large pipe ruptures plus loss of grid power plus operator errors.

    A single tube (or even a dozen tubes) having a minor leak is not at all a safety challenging event. In fact such an event doesn’t even call into action the many safety systems such as high pressure and low pressure injection, that are designed to cope with large leaks. Even those latter systems have backups, and diversity, in case some of them fail.

    Indeed, even if a much larger leak occurs and all the safety systems fail, the NRC’s stringent analysis (such as SOARCA) shows that not even 0.0001 person will die of radiation. Even with hundreds of such meltdowns, the expected radiation death rate is still well below 1. I can hardly imagine something safer than that. Imagine if you build a passenger aircraft, it crashes down, but everyone in the plane and out of it isn’t even scratched. Such an aircraft would be a very safe aircraft. Of course it isn’t the case. Everyone will die in the aircraft. Yet with the nuclear reactor, this level of safety exists.

    Considering this, it is strange that people keep using the safety argument against nuclear power. Nuclear power is far safer than pillows*

    *lots of people and children suffocate in pillows every year. Yet we don’t see people on the street carrying banners with wild outcries of “no more pillows”.

    People are not familiar with how nuclear plants are designed.