While TEPCO still doesn't know exactly what is causing the decrease in the amount of water being injected into the reactors to (supposedly) cool the reactors (see my previous post), the company has come up with the possible culprits: rust and plankton.
Yes, plankton. Why? Because the water being injected into the Reactor Pressure Vessels of Reactors 1, 2 and 3 at Fukushima I Nuclear Power Plant is not just the treated water after decontamination and desalination. The treated water is mixed with the filtered river water. Clearly, plankton escapes the filter.
From Jiji Tsushin (9/3/2012):
原子炉注水用の水に不純物＝流量減少の原因か－福島第１原発
Fukushima I Nuke Plant - Foreign matters in the water for the reactor may be causing the decrease in the water flow
東京電力福島第１原発事故で、原子炉冷却用の注水量がたびたび減少している問題について、東電は３日、注水用のポンプに入る前の水をタンクから採取してフィルターでろ過したところ、焦げ茶色の不純物が採取されたと発表した。水中のさびやプランクトンが配管を詰まらせている可能性もあるとみており、同社は不純物の分析やタンク内の清掃を進める。
Concerning the frequent problem of decreasing amount of water injected into the reactors for cooling at Fukushima I Nuclear Power Plant, TEPCO announced on September 3 that foreign matters in dark brown color were collected after they took the water from one of the storage tanks that feed the [treated] water to the pumps for water injection and filtered it. The company thinks it is possible that rust and plankton in the water are clogging the pipes, and will conduct the analysis of the foreign matters and clean out the tanks.
I remember reading the tweets from last year by one of the workers who tweet from the plant that the water treatment system (Kurion, AREVA at that time) was being clogged up with jello-like substance because the water being treated was in part filtered river water.
By the way, TEPCO, after consulting the regulatory agency no doubt, has lowered the minimum amount of water necessary for each reactor, so that the continued operation of the plant does not constitute a deviation from the safety regulations set by NISA.
From TEPCO's handout for the press (Japanese) on September 3, 2012:
The minimum amount of water per hour to be injected into the RPV:
Reactor 1: from 4.3 tonnes/hour to 3.8 tonnes/hour
Reactor 2: from 6.1 tonnes/hour to 5.4 tonnes/hour
Reactor 3: from 6.1 tonnes/hour to 5.4 tonnes/hour
There has been hardly any change in temperature at the bottom of the RPV in each reactor anyway. I'm curious to know what would happen if they completely stopped water injection.
There are two lines in the water injection system: CS (core spray) line and FDW (feedwater) line. The one with the greater fluctuation seems to be the FDW line, looking at TEPCO's data on September 3, 2012.
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12 comments:
Thank you LaPrimavera for reporting this inconspicious piece of information which reveals so much.
The aspect of biological contamination has been neglected totally in the past.
I really have to remind myself sometimes that quite a few "lower level organisms" are way more radiation resistant than complex biological organisms like humans.
Please keep reporting on this topic!
They were so close! Only 48.5 more years and the site cleanup would have been finished...
absolutely inexcusable that there would not be multiple redundant systems installed by now to keep these reactors cooled.
when Edano and his economic analysts say that electric costs would be double under the no-nuclear option, they are no doubt ignoring the huge costs of cleaning up nuclear mistakes, and the huge amount of damages that they will try to hide and not pay in such situations.
please, if you are Japanese, get out there and run for public office. Japan needs to replace these idiot government officials with people who have some common sense.
Does anyone have a link to articles or videos of Three Mile Island RPV that had Euglenozoa (or its relatives) floating around?
you mean like this?
http://www.apnewsarchive.com/1986/Reactor-Water-Grows-Bacteria-At-Three-Mile-Island/id-20babf1089235f85b3cd518a4af6732f
@ LaPrimavera
This topic which NRC seems very incurious about ("there is only anecdotal information", see Nureg-6988) makes me really curious.
After looking at some documents, I think the possibility cannot be excluded that "Tepco style plankton" could even be less harmless than one might think. It could be Legionella, Listeria, Pseudomonas and the like.
"The typical Pseudomonas bacterium in nature might be found in a biofilm, attached to some surface or substrate, or in a planktonic form, as a unicellular organism, actively swimming by means of its
flagellum."
-> pbadupws.nrc.gov/docs/ML0701/ML070170500.pdf
Nureg-6988 chapter 7 and 8
-> http://www.nrc.gov/reading-rm/doc-collections/nuregs/contract/cr6988/cr6988.pdf
Science Mag ("cloudy water"):
http://www.sciencemag.org/content/238/4832/1342.extract
Biofilms can speed up stainless steel corrosion up to 40 times:
-> http://pbadupws.nrc.gov/docs/ML0402/ML040230184.pdf
Biofilms in spent fuel pools are a common issue in US NPPs, including TMI
-> google "biofilm site:nrc.gov"
There are quite some radioactive bacteria and even worms.
Deinococcus radiotolerans thrives happily at 60 Sievert/h
-> http://www.ncbi.nlm.nih.gov/pmc/articles/PMC99018/
Luckily Deinococcus is only the most radiation resistant species, there are more of them:
-> see links at http://en.wikipedia.org/wiki/Deinococcus_radiodurans#Ionizing_radiation_resistance
But, sadly I didn't yet find any good information about which was found thriving in the TMI reactor vessel.
ooops lol, "quite some radioactive bacteria", what a mistake, I meant radiation resistant ones :)
In regards to stopping water injection, wouldn't it be better to keep melted fuel underwater to carry off radioactive contaminates for filtering rather than let dry blobs vent to atmosphere? Also, fresh groundwater might act as a moderator. You can always add boron to the feed water and maybe some bleach in this case to kill fungi.
Biofilms were used to produce gramicidin S (a cyclic decapeptide) to inhibit corrosion-causing, sulfate-reducing bacteria (SRB). In laboratory studies these biofilms protected mild steel 1010 continuously from corrosion in the aggressive, cooling service water of the AmerGen Three-Mile-Island (TMI) nuclear plant, which was augmented with reference SRB. The growth of both reference SRB (Gram-positive Desulfosporosinus orientis and Gram-negative Desulfovibrio vulgaris) was shown to be inhibited by supernatants of the gramicidin-S-producing bacteria as well as by purified gramicidin S.
http://www.springerlink.com/content/e9v6lwb9yj9mwp9a/
How about cavitation. Wouldn't it be about time for some replacement impeller blades (maybe some maintenance, too - hands-free of course ???) ???
"Reactor 3: from 6.1 tonnes/hour to 5.4 tonnes/hour"
lets do some math.
6 tonnes per hour = 0.1 tonnes per minute = 200lbs/minute = 25 GPM.
http://flexpvc.com/WaterFlowBasedOnPipeSize.shtml
given this is pumped in water, this is the injection of a 3/4" line at moderate pressure.
or a 1.25" gravity line.
That they are having trouble managing a 1"{ class line, bodes ill
@ anon 4:27
Thank you for this very interesting link. Even the nucleocrats in their despair seem resort to biological measures, which are less intrusive and chemically-damaging than biocides or aggressive chemicals to the delicate water chemistry which is required to reduce corrosion/leaching to a minimum...
@ pat
I have googled in vain for a previously Tepco-published schematic to determine the path the cooling water is being injected.
If I remember correctly, the cooling water is being injected via a path through the former water purification system.
The water purification system itself uses less large piping than the normal reactor cooling system. Iirc the piping was 2 or 3 inches diameter, and not really "aerodynamic" in the sense that the piping isn't straight, but has a lot of turnings and bends.
So, it could indeed be a biofilm whose growth causes problems.
Purging with aggressive chemicals probably is no solution, because this would also produce bad leaching effects on the corium, detrimental to the radiation situation.
It's really somewhat amazing what difficulties they have now to inject a quantity of water in a hour that was injected per second in normal operation.
@ anon 3:17
You are probably right in light of the fact that still nobody knows for sure that no corium entered the torus (and thus got below groundwater level).
As long as this hasn't been found out, a risk of recriticality would indeed remain if groundwater is allowed to fill up the basement.
At Chernobyl, the corium itself hasn't been cooled and this apparently didn't pose difficulties, no melting through the concrete.
(Don't know what would have happened without the tunnel-drilling below the reactor and the subsequent liquid nitrogen freezing, if that mattered at all in the outcome)
As the corium probably has cooled down below the melting temperature, the primary releases would be the noble gases entrapped in the corium which become free as the corium deteriorates from a lava-like form to a brimstone-like substance, like happening in Chernobyl.
But that watering and leaching only accelerates this process, and thus I somehow doubt the situation would be worsened substantially by stopping the water cooling.
Great tips, I like the guidelines you've laid out here...helpful!
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