Some new websites.

Here are two sites that are worth looking at... and which are PRO-NUCLEAR!

Nuclear Friends Foundation is located in India, and has as its focus the developing nuclear energy industry in that country. However, much of their information is wholly applicable elsewhere.

What is Nuclear? This site has as its mandate the "no-nonsense public education on the use of nuclear energy to help with the energy problem." Lots of information easily read on this site.

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And we also have another new ANS member's site: The Nuclear Diner! This awesome looking site was just launched this week and yours truly will be going straight away to sign up and begin participating. Cheryl Rofer is to be commended; I really like the presentation of this site. It's unique among nuclear websites and blogs.

That's three sites to check out that are pro-nuclear!

8:15 AM Eastern Wednesday October 12, 2011
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New video: Fukushima Daiichi cooling water injection

TEPCO has released its third video in the series which is intended to inform the public about operations and conditions at the Fukushima Daiichi site. This video is now up at the APR YouTube Channel... link below.

TEPCO is to be commended for its transparency vis a vis the content of these videos; the new video is perhaps the most graphic yet in terms of what MIGHT happen if cooling water injection is interrupted for various periods of time. Even the worst case scenarios (which frankly are only remotely likely, on the order of probability of the tsunami that caused the accident in the first place) are examined and described. A few notes may be helpful to non-nuclear readers and viewers, however.

-The equipment being employed on site and which is described in this video is wholly non standard. The arrangements of equipment external to the plants in terms of tankage, hoses, mounted pumps and also fire engines and diesel generators and pumps have been set up in stages over time since the accident in ever-improving layout, operation, redundancy and effectiveness. This should be kept in mind when viewing this video - in other words, that the possible scenarios are limited to Fukushima Daiichi Nos. 1 through 3 plants ONLY.

-In many places, TEPCO makes calculations or estimations which are clearly in error on the conservative side. As one example, TEPCO states that effects of metal-water reactions upon exceeding 1200C (in the unlikely event of prolonged feed interruption) are made using original core inventories even though it's proven that a large amount of the zirconium metal in the core has already reacted and thus is not actually available for further reaction. In this way, at every step of any process considering decay heat removal, estimates of the time required to react will be much shorter than actually required.

-When describing the dual fire engine flood feeding (core reflood) with two lines, TEPCO omits to indicate that one of the fire lines would feed through the feedwater injection line (feed sparger ring) while the other would feed through the core spray ring. At present, both are in use at all three reactors.

This video is very descriptive and outlines a number of possible but unlikely scenarios. TEPCO is clearly prepared for any further complications on site which would affect cooling of the damaged cores, and this video should calm a few of the most worried observers quite a bit.

APR YOUTUBE CHANNEL LINK - See "Fukushima Daiichi - Cooling Water Injection."

7:30 PM Eastern Sunday October 9, 2011
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73rd Carnival @ Next Big Future

73rd Carnival of Nuclear Bloggers: NEXT BIG FUTURE / Brian Wang

Brian Wang is hosting the 73rd Carnival over at Next Big Future; use the link above to see what the nuclear world is blogging about. The pro-nuclear world, that is.

2:42 PM Eastern Sunday October 9, 2011
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New "Favorite" videos at APR Youtube.

Readers here might wish to flip over to the APR YouTube Channel and view two videos that I have placed in the "Favorites" section.

One of them, very short, is from Dominion and discusses the NRC actions at North Anna following the earthquake.

The other is a video update from Southern Co. on the progress of construction of two Westinghouse AP1000 plants at Plant Vogtle. This video is very interesting and for those not familiar with nuclear plant construction I dare say might be fascinating.

Click here to get to the APR YouTube Channel.

5:00 PM Eastern Thursday October 6, 2011
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Davis-Besse vessel head replacement

As reported on the NRC blog, Davis-Besse has been shut down for replacement of its pressure vessel head. This plant is a Babcock & Wilcox pressurized water plant which went into commercial operation in 1978.

This plant has had extremely bad press because of a deficiency discovered during an NRC mandated inspection of its pressure vessel head. Below, an illustration of a plant like Davis-Besse (Babcock & Wilcox raised loop) showing the location of the pressure vessel head - a heavy, bolted lid which seals off the upper end of the reactor pressure vessel and through which are many holes to allow for installation of control rod drive mechanisms and for instrumentation.


Background: After a number of licensees (that is, utility companies operating nuclear plants) had reported cracking in vessel head penetrations to the NRC, the NRC issued a bulletin in 2001 which was bulletin 2001-01 calling for data concerning the various licensees' inspection programs to detect this type of possible failure. Davis-Besse addressed the requests of this memo during its first available refueling outage in February 2002, at which time a serious flaw was found in the vessel head which had been caused by a boric acid deposit. This threatened the integrity of the vessel head, and much bad press surrounded the discovery of this defect. The head could not be saved, and another had to be either made or found.

Fortunately -- at least, temporarily -- for Davis-Besse, there was a practically identical head available, unused, in Michigan. Consumers Power Company's Midland nuclear station, a two-unit Babcock & Wilcox plant, had been cancelled back in the middle 1980's due to a downturn in power demand generally and, specifically, a large number of on-site problems (diesel generator building sinking, improper welds in No. 1 plant's vessel, cracked support bolts for the reactor vessels, and not least, a well publicized $120,000 fine against Consumers Power for deliberately violating quality assurance requirements and for design and construction code violations.) This plant still had on site one vessel head which Davis-Besse could acquire and apply to its plant. However, since this head was of the same material as the original, it was susceptible to all the same potential corrosion problems as the first, so that Davis-Besse was required also to order a new head that would be applied later on.

Below, the unfinished (and actually never finished) Midland nuclear power plant as it looked in May, 1978. Press photo in APRA collection.



To make a long story short, the former-Midland head went on in 2004, and six years later upon inspection showed a few tiny cracks. Not serious ones, but cracks nonetheless. This was probably not particularly surprising to many in the industry. These cracks (which were repaired) led FirstEnergy to move the head replacement up from 2014 to the present time.

The NRC blog notes that over half of the pressurized water reactors in the United States have actually had their pressure vessel heads replaced. Thus, this is by no means an unusual procedure.

I will be making another post soon covering some details of pressure vessel construction that might be of interest as background for this type of maintenance.

4:36 PM Eastern Thursday October 6, 2011
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TEPCO: No hydrogen explosion at No. 2 plant

Thanks to Dan Yurman (who writes the popular blog IDAHO SAMIZDAT linked from this blog) we see that TEPCO has in part revised its official timeline of events at No. 2 reactor during the very earliest days of the accident. These changes can be summarized by simply saying that TEPCO now does NOT believe that there was a hydrogen explosion at No. 2 plant. The data leading to this conclusion is the record of a seismometer at the site that recorded only the explosion that partly destroyed No. 4 reactor building; no other major shock is seen at that time. Let's try to break this discovery, and its revelation by TEPCO, down into some terms that people can wrap their minds around.

The long-time readers of this blog (or anyone who uses the search box and looks for entries including "explosion" and "no. 2") know that from the very time of the explosion (for the employees did hear an explosion sound deep inside the No. 2 plant) and sudden drop in pressure of the suppression chamber at No. 2 plant, I have postulated two theories - First, a contained hydrogen burn, and second, a steam explosion caused either by core material dropping down from the core plate into water at the bottom of the reactor vessel or else from core material exiting the vessel and falling into water below the vessel. A steam explosion? Yes.

According to one of my favorite volumes for accident analysis in rapidly discoverable form, "The Second Nuclear Era," (see Fukushima Sources page) we find that extensive experimental analysis performed following the release of the Reactor Safety Study (WASH-1400) indicates a prevention of steam explosion in a contained volume if the absolute pressure of that volume is above 1 MPa (145 psia.) (See "The Second Nuclear Era" page 174-175.) This is to say that if the pressure is above this point when core material falls into a volume of water, there is a quenching action but not a steam explosion. Review of the TEPCO records of pressure in No. 2 plant reveal a great deal of time around the time of the explosive sound that pressure at the plant was BELOW this value. This means that if core material did suddenly fall into a volume of water, a steam explosion could have resulted.

Core design and power profiles would tend to reason against a sudden wholesale collapse of molten core material into a volume of water below; the failure would normally be expected to be much slower, with perhaps a better comparison being a trickle or occasional drop of progressive amounts of material. However, we should also note that there was a magnitude 9 earthquake prior to the accident and probable total core dryout prior to the explosive sound being heard inside No. 2 plant.

Now, before we jump off here, let's add this. There was at that same time a hydrogen explosion in No. 4 plant. We know that for sure; it partly destroyed the building. It's possible that the sound of this explosion was heard deep inside No. 2 plant... but almost immediately after this sound, both according to the archived TEPCO data and to TEPCO's new analysis, the dry well pressure at No. 2 plant suddenly dropped. It would be hard to believe that the hydrogen blast at No. 4 shook No. 2 plant enough to lead to a containment failure, although with all the other site damage which had occurred ... and the industry's general lack of complete analytical study of multi-reactor accidents on one site ... it's impossible even at this later date to say this could not have happened.

Having gone through all this so far, we have to stop and ask: "What does this new analysis really mean?" Well, it means that No. 2 plant was the only one of the three which had reactor cores installed that did not experience a hydrogen explosion. We can attribute this to the dislodging of a blowout panel on No. 2 plant when one of the other plants experienced an explosion; surely this vented hydrogen that might have caused an explosion identical to that at the other plants. (Item: No. 4 plant had no core installed; the explosion here was from hydrogen gas that leaked over from No. 3 plant through common vent piping.) This also means that the sound employees heard COULD have been that of No. 4 plant's explosion, but the drop in pressure of the dry well and the fluctuating pressure vessel pressures seem to indicate that a steam explosion upon release of core material into a volume of water isn't out of the question.

In the final analysis, there will likely be a different finding of damage at each plant, and each plant's differing failure timeline and physical condition will give us a great deal of information about preventing such accidents in the future. For now, we can only fairly puzzle at the new TEPCO finding of fact with educated guesswork such as I've engaged in above and continue to wait for direct analysis of plant components, at which time many of our driving questions about plant design and plant failure modes will finally be answered.

4:10 PM Eastern Thursday October 6, 2011
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ANS Nuclear Cafe / Rod Adams

Anyone who has been following events at Fukushima Daiichi should run over to the American Nuclear Society's "ANS Nuclear Cafe" blog and read Rod Adams' fine new article, fresh off the press. I could not have summed up the immediate situation vis a vis general press reporting ... and the truth ... any better.

ROD ADAMS ON FUKUSHIMA

I'd especially advise those in the media, and in particular those who always call up the same tired old media hacks, to read this article and think about the quality of the coverage they have provided, and how they can make that better in the future.

10:20 AM Eastern Wednesday 10/5
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