Uppdatering 00:20
Hyper rescue team verkar ha fixat problemet med bassängen i 3an!
Från Kyodo
The Tokyo Fire Department shot water into a spent-fuel pool of the No. 3 reactor in an operation that lasted more than 13 hours until 3:40 a.m., while the Defense Ministry plans to shoot water into a similar pool of the No. 4 reactor shortly.
More than 2,000 tons of water is believed to have been put into the No. 3 reactor's pool so far, exceeding the pool's capacity of 1,400 tons. Fuel rods used at the reactor were plutonium-uranium mixed oxide fuel, known as MOX, said to be harder to control than normal fuel rods made from uranium.
Uppdatering 21:30
Kyodo har skrivit liter mer om jodhalterna i dricksvatten i olika regioner. De skriver att värdena ligger över gränsen i Fukushima, men anger ingen siffra. Sen ger de följande:
Tochigi 77 Bq jod, 1.6 Bq cesium
Gunma 2.5 Bq jod, 0.22 Bq cesium
Saitama 0.62 Bq jod
Chiba 0.70 Bq jod
Tokyo 1.5 Bq jod
Niigata 0.27 Bq jod
Gränsevärdena är 300 Bq för jod och 200 Bq för cesium. Halveringstiden för Jod-131 är 8 dagar, för cesium-137 30 år och för cesium-134 2 år. Om nivåerna går högre är det nog dags för japanerna att börja äta jodtabletter i några veckor tills det sönderfallit bort. Cesium är värre, det stannar kvar länge, men hittills är nivåerna totalt försumbara, en tusendel till en hundradel av gränsvärdet.
För att jämföra vattennivåerna med nått så kan vi omvandla det till stråldoser och jämföra med bananer. En siffra i Bq ger på egen hand ingen information om hur farligt något är, olika radioisotoper sönderfaller med olika energier och ger ifrån sig olika typer av strålning(alfa, gamma, beta). Vet man aktiviteten, sönderfallsenergin och typen av sönderfall så kan man räkna om Bq till stråldosenheten Sievert. Som tur är finns det listor på faktorer för att konvertera en aktivitet till Sievert. Se tex tabell A:2 i detta dokumentet(säkerligen något föråldrat, men det enda jag hittade nu snabbt) och några andra i tabell 7.1 här. Dos konverteringsfaktorn för kalium-40 är 6.2-10^-6 mSv/Bq. En banan innehåller ungefär 14 Bq kalium-40 ger då alltså runt 0.1 mikroSievert.
Om man då går igenom listan på jod och cesiumhalter i vattnet så kan man få dessa stråldoser av att dricka 1 liter i respektive region, uttryckt i milliSievert och även i Bananekvivalenter. Att dricka en liter vatten just nu i Tokyo är alltså stråldosmässigt ekvivalent med att äta en tredjedels banan.
| Region |
Bq jod |
Bq cesium |
mSv jod |
mSv |
total mSv |
Bananer |
| Tochigi |
77 |
1,6 |
0,001694 |
0,000021 |
0,001715 |
17,148000 |
| Gunma |
2,5 |
0,22 |
0,000055 |
0,000003 |
0,000058 |
0,578600 |
| Saitama |
0,62 |
|
0,000014 |
0,000000 |
0,000014 |
0,136400 |
| Chiba |
0,7 |
|
0,000015 |
0,000000 |
0,000015 |
0,154000 |
| Tokyo |
1,5 |
|
0,000033 |
0,000000 |
0,000033 |
0,330000 |
| Niigata |
0,27 |
|
0,000006 |
0,000000 |
0,000006 |
0,059400 |
Uppdatering 19:34
Sex arbetare har fått stråldoser som överstiger 100 mSv rapporterar Kyodo.
100 mSv är ungefär en tiondel av den dos där man kan börja se akuta effekter. Gränsen för arbetare under de här omständigheterna har höjts till 250 mSv. Naturlig bakgrundsstrålning ligger runt 5 mSv per år i Sverige och runt 100 mSv/år på de ställen på jorden där den naturliga stråldosen är som högst. Ännu har alltså ingen fått direkt skadliga stråldoser på grund av Fukushimareaktorerna, man får hoppas att det fortsätter så.
Uppdatering 19:25
IAEA uppdatering
http://www.youtube.com/watch?v=YoQwYRj8Liw
1. Current Situation
The situation at the Fukushima Daiichi nuclear power plants is similar to that which I described yesterday.
Efforts to restore electrical power to the site continue. It is hoped that power will be restored to Unit 2 today, which will then act as a hub for restoring power to Unit 1. However, we do not know if the water pumps have been damaged and if they will work when power is restored.
Seawater is still being injected into the reactor pressure vessels of Units 1 and 2 and additional fire trucks have arrived, reinforcing the operation to spray water into the Unit 3 reactor building.
We still lack reliable validated data on water levels and temperatures at the spent fuel pools at Units 3 and 4.
Temperatures at the spent fuel pools in Units 5 and 6 have risen in the past few days but this does not give rise to immediate concern. Water continues to be circulated within the reactor pressure vessels and the spent fuel ponds at both units.
A second diesel generator is providing power for cooling at Units 5 and 6. We have been informed that holes have been made in the roof of the reactor building at Units 5 and 6 to avoid the risk of a hydrogen explosion.
Uppdatering 18:50
På tal om radioaktivitet i dricksvattnet... för att sätta saker i relation till varandra kan du läsa om banana equivalent dose.
Bananer är svagt radioaktiva på grund av att de är rika i kalium. Kalium består till 0.01% av kalium-40 som är radioaktivt med en halveringstid på 1.2 miljarder år. Aktiviteten i bananer är 120 Bq/kg, eller 15-20 Bq för en banan beroende på hur stor den är.
En aktivitet på 2.5 Bq per liter betyder alltså att du måste dricka 6 liter vatten för att få i dig samma mängd radioaktivitet som i en banan.
Uppdatering 15:30
Ny JAIF uppdatering.
Man har sprayat vatten över bassängen i 3an kontinuerligt under 7 timmar. Snart ska man börja med bassängen i 4an. För några dagar sen lyckades de spruta 30 000 liter vatten på runt 25 minuter. Om den takten har hållits nu så borde man isåfall sprutat runt en halv miljon liter vatten till 3an. Det borde vara runt en tredjedel av bassängens totala volym. Det låter lovande! Elkabel är inkopplad till både reaktor 1 och 2 men man har ännu inte dragit igång elen. Det är nog inte bara flippa över en kontakt med tanken på de skador som skett, speciellt i 1an, efter explosionerna. Men snart lär vi veta ifall pumparna fungerar eller ej. 2ans byggnad har inte skadats signifikant vilket ger hopp om att pumpar och annan utrustning ska fungera. Det är viktigast att få ordentlig kylning till härden i 2an eftersom inneslutningen är trasig på den reaktorn. Tryck, vattennivåer etc i reaktorerna verkar oförändrat.
Uppdatering 15:06
Kyodo rapporterar om att det handlar om 2.5 Bq jod och 0.38 Bq cesium per liter kranvatten. Gränsvärdena är 300 Bq Jod och 200 Bq cesium. SvD tror nog inte att man får plats med fler Bq per liter kranvatten, om man får tro deras rubrik att "kranvattnet i Tokyo är fullt av radioaktivitet"....
Uppdatering 13:45
Det står i tidningarna idag att man uppmätt strålning från vatten, mjölk och spenat i Tokyo och Fukushima området. Dom överskrider de gränsvärden som strålskyddsmyndigheten har satt upp. JAIF har en bra kort rapport om det. Gränsvärdena är definerade på ett sådant sätt att om man hade spenderat hela sitt liv på att äta produkter med de nivåerna så kan de vara skadliga. Dvs det är ingen omedelbar fara att äta det.
Reports were made by the related authorities that radiation exceeding the
government-set radiation level was detected from the sampled milk in Fukushima
Prefecture and the 6 samples of spinach in neighboring Ibaraki Prefecture. The limits
are stipulated as provisional regulation values under the national Food Sanitation Law.
・At the Ministry of Health, Labor and Welfare and the Prefectural governments,
monitoring and analysis will be conducted on the detected samples identifying where
the food were collected and bound to be shipped. The national government will consider
on taking necessary actions including ban on the product shipment and/or setting limits
to the food intake, on assumption that these radiation detections are associated with the
Fukushima NPS.
・These radiation limits have been set in accordance with International Committee on
Radiation Protection’s recommendations. The limits are provisional regulation values
based on the amount of food concerned in case that these would be continued to taken
in all through one’s life. The radiation measured from the samples pose no immediate
threat to health. For reference, the radiation detected in the milk, even if taken in all
through a year, is just equivalent to radiation dose of one-time conduct of CT scanning.
The radiation detected from the spinach is equivalent to one-fifth of one-time CT
scanning.
・The point where the milk was collected in the Fukushima Prefecture is more 30km
distance from the Fukushima #1 NPS. The radiation-detected spinach was collected in
Ibaraki Prefecture, neighboring to the south of the Fukushima Prefecture. The
prefectural boundary is 65 km distant from the NPS.
Reports were made by the related authorities that radiation exceeding the government-set radiation level was detected from the sampled milk in Fukushima Prefecture and the 6 samples of spinach in neighboring Ibaraki Prefecture. The limits are stipulated as provisional regulation values under the national Food Sanitation Law. ・At the Ministry of Health, Labor and Welfare and the Prefectural governments, monitoring and analysis will be conducted on the detected samples identifying where the food were collected and bound to be shipped. The national government will consider on taking necessary actions including ban on the product shipment and/or setting limits to the food intake, on assumption that these radiation detections are associated with the Fukushima NPS. ・These radiation limits have been set in accordance with International Committee on Radiation Protection’s recommendations. The limits are provisional regulation values based on the amount of food concerned in case that these would be continued to taken in all through one’s life. The radiation measured from the samples pose no immediate threat to health. For reference, the radiation detected in the milk, even if taken in all through a year, is just equivalent to radiation dose of one-time conduct of CT scanning. The radiation detected from the spinach is equivalent to one-fifth of one-time CT scanning. ・The point where the milk was collected in the Fukushima Prefecture is more 30km distance from the Fukushima #1 NPS. The radiation-detected spinach was collected in Ibaraki Prefecture, neighboring to the south of the Fukushima Prefecture. The prefectural boundary is 65 km distant from the NPS.
Länkar
SVD Kranvattnet i Tokyo fullt av radioaktivitet
DN Radioaktiv mjölk nära Fukushima
Aftonbladet Radioaktiv jod i Tokyos kranvatten
Uppdatering 11:20
Nu är vi inne på över en vecka i dramatiken. Nyhetsflödet avtar och läget verkar ta hoppfulla steg mot stabilitet. JAIF har släppt en ny statusuppdatering där man inte ser något direkt nytt jämfört med igår. NISA har även de släppt en uppdatering som är något äldre, daterad 8 på lördag morgon och tiden i Japan är nu nästan halv 8 på kvällen. Man fortsätter att spruta vatten i bassängerna enligt Kyodo och med överflygning med IR kamera har man sett att bassängtemperaturerna är 100 grader eller lägre. Det betyder givetvis att det är vatten i bassängerna. Situationen i 3ans bassäng sägs vara under kontroll och man ska nu fokusera på 4an.
Inkopplingen av el verkar ta längre än förväntat och nu rapporterar Kyodo att återställningen av elen vid 2ans reaktor kommer fortsätta under söndag.
Den två dieselgenerator man fått igång vid 5an och 6ans reaktor klarar av att driva kylningen både för bassängerna i 5an och 6an och reaktorerna verkar inte vara i någon fara.
Statusen för de tre skadade reaktorerna fortsätter vara något oklart. Är det en total härdsmälta, har smältan stannat på tankbotten, det är frågor man nog inte vet svar på. Men havsvatteninpumpningen fortsätter kontinuerligt och man har slutat ventilera inneslutningarna. Det borde, som jag skrev igår, innebär att man nu lyckas hålla härden kyld utan större ångbildning.
Uppdateringarna under dagen idag kommer ske mer som sammanfattningar av läget.
Här nedan är ett klipp från NISA rapporten.
・ Hyper Rescue Unit of Tokyo Fire Department carried out water spray
(60 ton). (March 19th)
Started water spray : 00:30
Ordered to stop water spray : 00:50
Completed water spray : 01:10
< Situation of operations in the site and recovery of the power supply >
・ Confirming the specific plan of operations for the recovery of the
external power supply to Units 1, 2, 3 and 4. (Electric power receiving
from the external transmission line of Tohoku Electric Power Co. and
the route via transformer substation of TEPCO) (08:00 March 19th)
・ The second unit of Emergency Diesel Generator (A) for Unit 6 has
started up. (04:22 March 19th)
・ Pump for Residual Heat Removal (RHR)(C) for Unit 5 started up and
cooling of Spent Fuel Storage Pool has started. (Power supply :
Emergency Diesel Generator for Unit 6) (05:00 March 19th)
・ Hyper Rescue Unit of Tokyo Fire Department carried out water spray (60 ton). (March 19th) Started water spray : 00:30 Ordered to stop water spray : 00:50 Completed water spray : 01:10 < Situation of operations in the site and recovery of the power supply > ・ Confirming the specific plan of operations for the recovery of the external power supply to Units 1, 2, 3 and 4. (Electric power receiving from the external transmission line of Tohoku Electric Power Co. and the route via transformer substation of TEPCO) (08:00 March 19th) ・ The second unit of Emergency Diesel Generator (A) for Unit 6 has started up. (04:22 March 19th) ・ Pump for Residual Heat Removal (RHR)(C) for Unit 5 started up and cooling of Spent Fuel Storage Pool has started. (Power supply : Emergency Diesel Generator for Unit 6) (05:00 March 19th)
Länkar
http://www.svd.se/ego/mainColumn_s185/http://www.svd.se/nyheter/utrikes/japan-direktrapportering-fredag_6019363.svd
http://www.svd.se/ego/mainColumn_s185/http://www.svd.se/nyheter/inrikes/nordbor-far-hjalp-att-lamna-japan_6014989.svd
http://www.dn.se/nyheter/varlden/redo-att-do-i-kampen-mot-hardsmaltan
http://www.aftonbladet.se/nyheter/jordskalvetijapan/article12746815.ab
http://www.expressen.se/nyheter/liverapport
http://www.svd.se/ego/mainColumn_s185/http://www.svd.se/opinion/brannpunkt/riskerna-med-karnkraft-minskar_6022685.svd
http://www.svd.se/ego/mainColumn_s185/http://www.svd.se/nyheter/utrikes/radioaktiv-mjolk-nara-fukushima_6022631.svd
http://www.dn.se/nyheter/varlden/tarar--i-vantan-paatt-krisen-ska-losas
http://www.expressen.se/nyheter/liverapport
.png)
). (more...)
)
Day thirteen after the tsunami
Thursday, March 24th, 2011Update 22:30(UTC)/23:30(CET)/07:30/(JST)
I end todays updates with some heartbreaking pictures from the tsunami disaster. Its very hard to even just watch these pictures, I hope the resilience of the great japanese people will astonish the world when they rebuild after this disaster.
http://blogs.denverpost.com/captured/2011/03/18/captured-japan-earthquake-and-tsunami-one-week-later/2838/
Update 21:20(UTC)/22:20(CET)/06:20(JST)
Some Austrian researchers have analysed data from detectors used to verify the comprehensive test ban treaty and their analysis show that the emissions of iodine and cesium from Fukushima is approaching the same level as from the Chernobyl accident. Fukushima emitted around 1,3*10^17 Bq iodine per day the first days and the total emission from Chernobyl was 1,7*10^18 Bq. By now the iodine emissions must be much lower due to the short half life of iodine and they haven't reported any containment venting for about a week if my memory serves me right. The core inventory of I-131 is now reduced by more than half due to decay(half life 8.02 days) and the other iodine isotopes have even shorter half life. It will be interesting to see more data on this.
It's good that the evacuation from the area around the reactor was brisk and that iodine pills have been supplied. So far the ground fallout data from MEXI doesn't look very bad but it might be due to the direction of the wind as stated in the article.
Update 19:15(UTC)/20:15(CET)/04:15(JST)
It is in the middle of night in Japan right now and the news flow is always a bit slower then for obvious reasons. But NISA has still released a new update (values from 18:05 which makes it older than the JAIF updated I wrote about in the last blog update. They have released a PDF with pictures from the control rooms and plant area, here is a direct link to it. They are ne day old and that is why the control room for reactor 1 is dark(they restored power to it today).
17 workers in total has exceeded a total dose of 100 mSv.
Uppdate 16:00(UTC) / 17:00(CET) / 01:00(JST)
New JAIF and NISA(link 1, link 2, link 3) updates. NISa has added a new file to its update that gives more data, among them the dose rates within the containments. The NISA uppdate is from 11:00 and the JAIF update from 22:00 JST. JAIF numbers first followed by NISA within ().
Reactor 1:
Water level in the core: 1.7 meters(1.7m) below the top of fuel assemblies
Core pressure: 523 kPa (532 kPa)
Containment pressure: 390 kPa (400 kPa)
Core temperature(feedwater nozzle): 175 Celsius
Dose rate within containment: 43.5 Sv/hour
Reactor 2:
Water level in the core: 1.15 meters(1.15m) below the top of fuel assemblies
Core pressure: unknown
Containment pressure: 110 kPa (110 kPa)
Core temperature(feedwater nozzle): 100 Celsius
Dose rate within containment: 48.4 Sv/hour
Reactor 3.
Water level in the core: 2.3 m (2.3 m) below the top of fuel assemblies.
Core pressure: 137 kPa (137 kPa)
Containment pressure: unknown
Core temperature(bottom head): 185.,5 Celsius
Dose rate within containment: 55.9 Sv/hour
The pressure in number 1 went up a bit and then started going down. Temperature has been lowered about 70 degrees Celsius. Dose rate by main gate seems to be on a slow decline. Iodine levels in Tokyo water has gone down below the infant limit of 100 Bq/liter. Testing of pumps are ongoing in reactor number 3. More and more vegetables with levels far exceeding the limits for cesium and iodine is found.
Uppdate 9:00(UTC) / 10:00(CET) / 18:00(JST)
During night(swedish) JAIF(link 1, link 2) and NISA(link 1, link 2) has released new updates. The NISA updates(the schematics of the reactors attached at the end of the post) is by the time of writing 13 hours old and the JAIF update 2 hours old. I will write the JAIF numbers below first and the NISA numbers within parenthesis so one can se the change over the last 11 hours.
Reactor 1.
Water level in the core: 1,7 meters(1,7m) below the top of fuel assemblies
Core pressure: 510 kPa (511 kPa)
Containment pressure: 385 kPa (385 kPa)
Core temperature(feedwater nozzle): 243 Celsius
The situation has been stable for the last 11 hours. Containment pressure and core pressure is up about 20 kPa since yesterdays update. The containment pressure is a bit to high for comfort I would say. All though the highest it has reached during the entire accident was about 800 kPa in one of the reactors so it can plausibly handle even a doubling in an emergency, but if it doesn't go down soon I am afraid TEPCO are going to have to vent the containment. Venting now could be problematic since the steam will contain quite a lot of activity and it could hamper work for hours due to radiation levels. On a positive note, the lights are now on in the number 1 control room showing that there is some progress in restoring electricity. Lets hope the pace will accelerate soon and that the coolant pumps are functional or at least easy to replace!
Reactor 2.
Water level in the core: 1,2m (1,2m) below the top of the fuel assemblies
Core pressure: Unknown(the readings claim below atmospheric pressure so the gauge is most likely broken)
Containment pressure: 105 kPa (105 kPa)
Core temperature(feedwater nozzle): 102 Celsius
Compared to yesterday pretty much nothing has changed. The core temperature and both core pressure and containment pressure remains low. Nothing new about the radiation levels in the turbine building(reported to be around 500 mSv/hour yesterday) that prevents access for repairing equipment.
Reactor 3.
Water level in the core: 2,3 m (2,3 m) below the top of fuel assemblies.
Core pressure: (142 kPa)
Containment pressure: unknown(JAIF states "downscale")
Core temperature(feedwater nozzle): 80,7 Celsius
The JAIF update has changed the status of the containment from "might be not damaged" to "not damaged", that is very good news indeed! It means the only damaged containment is on reactor 2 that appears to be quite stable and cool. Sometime during yesterday they seem to have been able to hook up a pump to one of the pipes leading to the spent fuel pool and they can now provide seawater through the cooling and purification line. Hopefully that means there is no need anymore for blind spraying of the number 3 building. Yesterday they managed to restore lights to the control room, but no news about instrumentation or the filtration system to bring down radiation levels inside the control room.
Reactor 4.
The concreter pump truck continues to deliver water to the spent fuel pool at a rate of 50 000 liters per hour.
General remarks:
We have been hoping for the electricity to be restored to the pumps etc since Saturday now. There is no explanation on what problems they have encountered or the status of the pumps. In the Fukushima Daini plant they had to replace pumps after the quake and tsunami so perhaps pumps needs to be replaced at Daiichi as well. The situation appears stable at the moment, but seawater cooling can not continue forever. At some point the salt depositions in the core will start to cause real problems but I do not know what time span we are talking about. If one estimates the salt deposition from the amount of water that could have been evaporated by the decay heat so far one ends up with several tens of cubic meters of salt. It's hard to know where all of this salt has been deposited though since we don't know the flow path of the water. On the bright side it seems like the workers are able to access more of the reactor building now as indicated by the fact that they have switched the path of seawater injection for the number 3 spent fuel pool and the number 1 reactor.
Three workers have been exposed to close to 200 mSv. It's encouraging that they manage to keep the worker doses below 200 mSv so far. If TEPCO is being honest then its unlikely we will see any acute radiation sickness in workers.
Iodine levels in water and vegetables in prefectures close to Fukushima continues to be high.
We'll try to keep it in english from now on...
Update 07:30 (UTC) / 16:30 (JST)
JAIF just released their 16:00 update. One bit of happy news there is that they now write that the number 3 containment vessel is "Not damaged".
Screenshot of the update will follow soon when the guy that has access to saving PDF to JPG gets to his computer.
Radiation levels in the Tokyo water also seem to be dropping again... but it's too soon to speak of any general trends. Also no new word on Caesium-137 in farmlands or water.
The work to bring electricity to Fukushima I continues (slowly).
Tags: containment, Fukushima, Fukushima I, Japan, kärnkraft, Reactor, Tokyo, tsunami
Posted in Commentary, English, Fukushima | 11 Comments »