que Sv no es diminutivo de sievert........
Terremoto y tsunami escala 9 en Japón (V)
- Autor del tema fibraillo
- Fecha de inicio
- Estado
Pedro Solves
Madmaxista
20.14h. 9.523 víctimas mortales y 16.094 desaparecidos.
19.33h. Neutron beam, a kind of radioactive ray, has been observed 13 times at Fukushima plant since tsunami - Kyodo Neutron beam observed 13 times at crippled Fukushima nuke plant | Kyodo News
17.42h. Quake-ravaged Japan digs mass graves reut.rs/hwKWRc
17.25h. TEPCO, which operates Japan's nuke reactors, expects to continue rolling blackouts in Kanto region for at least a year Japan quake live blog: Government will try to count orphans – This Just In - CNN.com Blogs
14.34h. FLASH: Japan nuclear agency: Radiation level at Fukushima reactor No.2 at highest level recorded so far
13.18h. La contaminación en el agua de Tokio se mantiene, así como en verduras y leche de Fukushima. Niveles por encima de lo legal pero no letales.
10.45h. Japan govt official says black smoke at Fukushima reactor no. 3 will not become a major issue
10.21h. 9. 408 víctimas mortales y subiendo. En el Gran Terremoto de Kanto en 1923, murieron más 100.000 personas.
08.57h. No flames seen from no.3 unit at Fukushima plant - NHK
08.42h. Black smoke seen rising from no.3 nuclear reactor at Fukushima plant - NHK
08.30h. Aconsejan no beber agua del grifo en Tokyo, se han hallado elevados niveles de yodo radioactivo
07.36h. La radiación en un radio de 40 kilómetros en torno a Fukushima-1 supera 400 veces los niveles normales.
06.23h. Radioactive iodine exceeding limit for infants detected in tap water in Tokyo - Kyodo
04.01h. Two workers at Fukushima nuclear plant injured while working on power restoration - Kyodo
03.59h. Japan PM tells Fukushima residents not to eat leafy vegetables over radiation concerns - Kyodo Kan asks Fukushima residents not to eat leaf vegetables over radiation | Kyodo News
03.41h. Workers at Japan nuclear plant unable to continue work at reactor no.2 due to high radiation levels - Nuclear safety agency
03.35h. No. 2 reactor power repair work halted, 500 millisievert per hr radiation found. english.kyodonews.jp
03.29h. 9301 muertos. 13786 desaparecidos.14722 casas destruidas y 5012 parcialmente.264000 refugiados.
03.27h. Japan cabinet secretary urges other countries to take "logical stance" on restrictions on imports of Japanese foods
03.01h. Japan nuclear regulation official says temperature in Fukushima’s No.1 reactor above designed limit but no immediate danger.
^^Desde aqui hacia arriba 23 De marzo ^ ^
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Desde aqui hacia abajo 22 de marzo
13.25h. Power lines are hooked up to all six reactor units at Japanese nuclear plant, utility says
10.00h. Pool for storing spent fuel at crippled Japanese nuclear plant is heating up, with temperatures around boiling point, official says - AP
08.22h. Japan nuclear safety agency: White smoke rising from reactor no.2 of stricken plant likely to be steam from spent-fuel pool
08.00h. 9.079 víctimas y 12.645 desaparecidos hasta ahora. (ventepayokohama)
05.22h. Tokyo Electric Power resumes rolling blackouts after a three-day suspension - Kyodo Tokyo Electric resumes rolling blackouts after 3-day suspension | Kyodo News
04.37h. Los niveles de radiación empiezan a bajar otra vez, después de dos días el doble de altos de lo normal.
04.23h. 8.805 víctimas mortales confirmadas, de ellas, 4.080 están identificadas. Hay 12.654 desaparecidos. (ventepayokohama)
04.17h. Japan govt spokesman Edano says there are no plan yet to expand evacuation zone near damaged plant - Kyodo
03.51h. Iodine-131 has been detected in sea water near the Fukushima N-plant at 127 times safe levels; cesium-134 at 25 times safe levels.
03.02h. Work to restore power to Fukushima reactors delayed as white plume, smoke rise from No. 2, No. 3 sites - Kyodo TEPCO gauges nuke crisis' impact on sea, tries to resume restoring work | Kyodo News
02.54h. TEPCO says resumed work on reactors, steam not problematic reut.rs/gXPvT3 (htpp://reut.rs/gXPvT3)
02.22h. Tepco says to resume work in restoring power to reactors, only steam coming from reactors 2 and 3 now.
02.17h. Sale humo de los reactores 2 y 3.
^^Desde aqui hacia arriba 22 De marzo ^ ^
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Desde aqui hacia abajo 21 de marzo
11.21h. Ahora sale humo blanco del reactor 2. Todavía no se sabe el origen del humo gris del reactor 3 de esta tarde. Yomiuri On-Line i“Ç”„V•·j // Sale humo grisáceo del reactor número 3 -> (+3 minutos) No se conoce el origen de ese humo.
10.30h. Radioactividad en Tokio llevan subiendo todo el día aunque mucho menos que la semana pasada. 0.052uGy/h esta mañana, 0.13uGy/h ahora. (kirai)
09.56h. No change seen in radiation levels at Fukushima nuclear plant after smoke sighted near No. 3 unit.
09.38h. Se produce la evacuación de varios trabajadores que estaban en algunas zonas problemáticas (temporalmente).
09.30h. Los trabajadores de la planta nuclear de Japón han conectado los cables de alimentación a los reactores 3 y 4
08.39h. La OMS cree la radiación detectada en ciertos alimentos en Japón es 'mucho más seria' de lo previsto
08.00h. 8.649 víctimas mortales confirmadas, de ellas 3.550 están identificadas. Los desaparecidos ascienden a 12.877.
04.54h. La agencia de seguridad nuclear japonesa advierte de que la presión crece en el reactor número 3 y considera tomar medidas para liberar la presión del núcleo.
00.54h.
* Nota del OIEA: Las autoridades japonesas informan que los trabajadores en la central nuclear de Fukushima I han llevado los reactores de las unidades 5 y 6 a parada en frío. Esto significa que ambos reactores se encuentran a seguro, con los sistemas de refrigeración estables, bajo control y con temperatura y presión bajas en el interior. Prosiguen los esfuerzos para restaurar los sistemas en las unidades 1, 2 y 3. La unidad 4 estaba cerrada por mantenimiento, con todo el combustible retirado del núcleo, antes de que se produjera el terremoto del 11 de marzo.
* Nota del OIEA: Fukushima I.
* Unidad 1: Se restablecieron los indicadores de presión en la vasija (19/03).
* Unidad 2: No se ve humo saliendo de la unidad (19/03). Se ha comenzado a bombear 40 Tm de agua marina a la piscina de combustible gastado.
* Unidad 3: Se ha visto humo blanco saliendo del edificio, pero menos que otros días (19/03). Se empieza a echar agua desde camiones a la piscina de combustible gastado (20/03).
* Unidad 4: El Ejército Japonés comienza a echar agua al edificio desde camiones (20/03).
* Unidades 5 y 6: La temperatura en las piscinas de combustible gastado ha descendido considerablemente (20/03). Restablecimiento de la red eléctrica: Se ha conectado energía eléctrica exterior a un transformador auxiliar y los paneles de distribución de la unidad 2. Se sigue trabajando para alimentar equipos específicos de la misma. Contaminación radiológica: Se confirma la presencia de yodo-131 “por encima de límites” en tres muestras de leche, y Cesio-137 “por debajo de límites” en otra. En Ibaraki, se ha detectado yodo-131 y cesio-137 “por encima de límites” en vegetales (cebollas, espinacas). Se ha detectado yodo-131 “por debajo de límites” en 6 de 46 muestras de agua potable.
^^Desde aqui hacia arriba 21 De marzo ^ ^
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Desde aqui hacia abajo 20 de marzo
12.15h. 8.277 víctimas mortales confirmadas.
12.00h. La presión del reactor 3 fluctúa. Finalmente no se ha producido la liberación de gas.
09.56h. Los ingenieros han logrado restaurar la electricidad reactor 2, según la agencia de noticias Kyodo.
07.15h. La presión en el reactor 3 aumenta. Se van a liberar gases radioactivos a la atmósfera para reducirla. Medida arriesgada pero necesaria.
04.17h. Se calcula que el tsunami ha dado de baja de la suscripción de la vita a más de 15.000 personas en una sola prefectura.
03.55h. US Forces Japan provided 150 nuclear, biological, and chemical suits to TEPCO employees.
01.55h. Japan plant operator says temperature at spent fuels pools at reactors 5 and 6 at most normal levels according to Kyodo News.
^^Desde aqui hacia arriba 20 De marzo ^ ^
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Desde aqui hacia abajo 19 de marzo
23.27h. Los bomberos dejan de lanzar agua contra los reactores en Fukushima
23.16h. Engineers have attached a power cable to the No. 1 and No. 2 reactors, and hope to restore electricity on Sunday prior to an attempt to switch the pumps on. Additionally, they aim to reach No. 3 and 4 later in the day.
11.30h. Terremoto 6,1 grados, en Ibaraki, al noreste de aquí.
10.00h. Japan's nuclear safety agency: power cable connected to stricken nuclear plant's no.2 reactor
08.47h. Yukio Edano: Leche y espinacas de Fukushima con niveles de radiación perjudicial para la salud Nota: No es letal y practicamente, tampoco es dañina.
08.00h. Japón informa de que se aprecia cierta estabilidad en el reactor número 3.
07.00h. Llevan 7 horas seguidas echando agua al reactor 3. 3 toneladas al minuto, Con un sistema automatico que permite que no haya gente en el sitio.
04.24h. 7.197 es el nuevo recuento de víctimas mortales.
04.14h. 100 personas, incluyendo especialistas en el diseño de las vasijas de contención, son enviados a Fukushima.
03.06h. Japan nuclear plant operator starts using water pump at reactor No.5: Jiji News
01.07h. Here's the latest Reuters story, says engineers attached a power cable to the outside of the plant and cabling inside the plant has started Japan lays power cable in race to stop radiation | Reuters
^^Desde aqui hacia arriba 19 De marzo ^ ^
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Desde aqui hacia abajo 18 de marzo
15.30h. La radiación liberada en la Central Nuclear de Fukushima puede ser MORTAL.
10.08h. The Japanese nuclear agency says it expects electrical cables to be connected to the generators at reactors 1 and 2 by Saturday morning.
09.55h. Japan's nuclear safety agency says there has been a level 5 incident at reactors 1, 2 and 3, and a level 3 incident at reactor 4, of Fukushima Daiichi.
04.21h. El ejército de Japón y el departamento de bomberos movilizan los camiones de bomberos para iniciar a rociar con agua el reactor nº3 de la central de Fukushima por la tarde.
03.40h. Boletín oficial sobre el estado de las dos centrales. Click aquí
03.00h. Yukio Edano da buenas noticias: Más agua y electricidad llegando a los reactores. Niveles de radioactividad bajando.
02.40h. Tres reactores de la central de Fukushima expulsan humo blanco. El humo o vapor proviene de los reactores 2, 3 y 4.
02.30h. Japan nuclear agency says reactor No.2 smoke could be steam from spent fuel pool or smoke from explosion in suppression chamber
02.25h. Confirmadas 5.692 víctimas mortales por el terremoto y el tsunami. Hay 9.506 desaparecidos.
01.00h. Militares estadounidenses detectan mas radiación que la anunciada por Japón
^^Desde aqui hacia arriba 18 De marzo ^ ^
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Desde aqui hacia abajo 17 de marzo
21.51 h.Wikileaks "está trabajando" para publicar documentos sobre la situación de Japón.
19.27 h.El OIEA ha informado que se pretende "volver a conectar la energía a la unidad 2, una vez que el rociado de agua sobre el edificio del reactor de la unidad 3 se haya completado".
18.43 h.El OIEA ha informado que los ingenieros han sido capaces de poner el cable de alimentación externa a la unidad 2 en la planta nuclear.
17.51 h.La radiactividad aumenta en torno a Fukushima, según la OIEA
17.00 h.
"La única manera posible de estabilizar la situación" en la central de Fukushima es proporcionar agua en cantidad suficiente para enfriar las instalaciones, según la Autoridad de Seguridad Nuclear francesa (ASN).
16.22 h.
Una gran nube radiactiva procedente de Japón llega a California este viernes ( Las consecuencias de la nube para la salud son 'extremadamente pequeñas'
14.43 h.
La agencia de noticias Kyodo afirma, citando a un portavoz de la operadora Tepco, que el suministro eléctrico para la central de Fukushima podría ser retomado hoy mismo
13.30 h.
Japóncomenzará a lanzar agua desde el aire al reactor número 3 de la central. Afirman además que está saliendo "humo blanco"delnúmero2
12.22 h.Cinco camiones cisterna del Ejército han sido enviados a la central nuclear con 30 toneladas de agua para intentar refrigerar los reactores. Imposible utilizar el cañón por los altos niveles de radiación.
9.56 h.
El Gobierno japonés insiste en que, por el momento, no hay planes de ampliar el área de evacuación momento
9.09
El Gobierno japonés alerta del riesgo de que se produzca un gran apagón este jueves en el área de Tokio debido a los problemas de suministro de electricidad.
8.24
Los niveles de radiactividad en la central apenas han variado a pesar de que los helicópteros de las Fuerzas de Autodefensa han vertido miles de litros de agua marina sobre el reactor número tres.
7.37 Comienza a rociarse con agua, lanzada desde helicópteros de las Fuerzas de Autodefensa, el reactor número tres en un intento por enfriarlo.
3.31
La alimentación eléctrica en la central nuclear de Fukushima se podría restablecer al mediodía (hora de Japón)
2.42
Son varios los helicópteros que sobrevuelan la central de Fukushima para rociar con agua los reactores 3 y 4 y tratar así de rebajar su temperatura.
1.54
Un helicóptero de las fuerzas de autodefensa japonsas ha lanzado una gran cantidad de agua sobre uno de los reactores de la central de Fukushima, según informa la televisión japonesa NHK, A la vez que el camion han comenzado por el reactor 3, el helicoptero puede verter 6 toneladas de agua sobre el reactor
1.23
Tokyo Electric says getting ready to inject water into reactor No.3 at Fukushima Daiichi TEPCO dice que estan preparados para inyectar agua en el reactor 3 de Fukushima (Parece que lo hará un camion antidisturbios de la policia de tokyo). En NHK dicen que es su ultima medida....
^^Desde aqui hacia arriba 17 De marzo ^ ^
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Desde aqui hacia abajo 16 de marzo
23.45
El canal de televisión NHK ha informado de que el radio de evacuación alrededor de la central nuclear de Fukushima será ampliado debido al peligro radiactivo, lo que afectará a 28.000 personas más, que deberán abandonar sus casas.
22.16
El que se haya agotado el agua en el depósito de combustible del reactor número 4 hace imposible impedir el aumento de temperatura en las barras de combustible, lo que podría llevaría a una fusión del nucleo.
20.10
Los trabajadores de la planta nuclear se enfrentan a una "dosis letal" de radiación
19.20
"La piscina de combustible del reactor 4 está sin agua, los niveles de radiación son extremademente altos" Reuters.
19.14 h.
La compañíanipona Tepco hace todo lo que puede pero "existen demasiados elementos que aún desconocemos", revela Yukiya amano, director general del OIEA.
17.17
Los reactores 1, 2 y 3 tienen parte de las barras de combustible al descubierto
17.08
El Pentágono ordena a sus militares que no se acerquen a la central de Fukushima.
16.07
Según el OIEA, las autoridades japonesas están preocupadas sobre las condiciones de la piscina de combustible nuclear gastado en dos reactores (las unidades 3 y 4).
15.48
El alcalde de la ciudad de Ishinomaki (en la prefectura de Miyagi) dice que probablemente haya 10.000 desaparecidos en la localidad.
13.51
La OMS reconoce una situación "extremadamente preocupante" pero afirma que Japón tiene los "mejores expertos".
13.13
Japón utilizará cañones de agua para enfriar el reactor 4 de la central nuclear de Fukushima.
10.27
La elevada radiactividad impide el lanzamiento de agua sobre la central nuclear de Fukushima desde el aire.
8.30 Un helicóptero del ejército japonés sobrevuela la central de Fukushima para intentar arrojar agua.
4.50
Los trabajadores regresan a la central nuclear de Fukushima, según Reuters.
3:30
El gobierno japonés dice que los técnicos han dejado de operar en el Central (CNN).
02:10 h.
Vuelve a verse humo en el nº4 de Fukushima -NHK
02:00 h.
Según Kyodo, la compañía estadounidense General Electric se ha ofrecido a proporcionar asistencia técnica al gobierno japonés y a TEPCO. Se espera que más de 1.000 ingenieros transmitan sus conocimientos y podrían suministrar 10 turbinas de gas montadas en camiones para suplir la falta de corriente en la planta
01:52 h.
Se ha evacuado con exito los 20kms alrededor de Fukushima en su totalidad. -BBCNews La webcamp de TEPCO vuelve a estar on-line
01:45 h.
Lanza acido borico a la piscina del nº4 solo seria efectivo en caso de que hubiera una fusion del nucleo, de todo modos nadie se puede acercar. -twitter
01:20 h.
En Tokyo el civismo es maximo a las 9:00, las empresas estan instando a quedarse en casa, pero parece que pocos empleados siguen el consejo. -BBCNews
01:10 h.
Los 50 de Fukushima estan cubriendo las barras de la piscina del nº4 con acido borico. -Kyodo News
01:00 h.
TEPCO consideran que tirar acido borico desde helicopteros es una medida que no funciono bien en Cherno. La tripulacion del helicoptero ve improbable alcanzar el objetivo a cubrir, y hay dudas de que parte de ella ni tan siquiera llegue al reactor dañado -BBCNews
00:55 h.
Tokyo e Ibaraki se han quedado sin Gasolina -BBCNews
00:53 h.
Casi 1.000.000 de casas sin luz en el norte del pais, al menos 1.500.000 hogares estan sin agua. La temperatura ambiente cercana a 0 grados. -BBCNews
00:45 h.
NHK confirma que hay entre unas cosas y otras mas de 440.000 japoneses en situacion refugiados. Algunos sin comida ni agua.
-Reuters
00:40 h.
Se confirma que el nucleo del 1 y del 3 estan parcialmente fundidos. En el 1 al menos al 70%. -Reuters.
00:30 h.
TEPCO esta considerando la posiblidad de lanzar acido borico al nº4 desde un helicoptero. -Reuters.
00:20 h.El Gobierno informa que el incendio del edificio del reactor nº4 esta controlado. -BBCNews
00:15 h. TEPCO Informa que Las barras de combustible del reactor 1 y 3 estan dañadas al 75% y al 30% respectivamente. -Kyodo news.
00:00 h.
Los expertos dicen que hay un ligero riesgo para la salud de los ciudadanos de Tokyo. -Reuters
Perturbado
Madmaxista
38 microREM son 0,38 microSV o 380nSV--- CORRIJO PORQUE TAMBIÉN ME EQUIVOQUE
Recordar las escalas
10^-3 milis
10^-6 micros
10^-9 nanos
10^-12 picos
10^-15 femtos
Última edición:
geb
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Lo que me estás diciendo es que el daño que un milisievert le hace a un bebé (tanto a corto como a largo plazo) es mayor que el que le hace a un adulto. Pero la noticia original dice que el número de milisieverts que recibe el bebé es mayor que el del adulto, y eso es lo que no entiendo.
Yo no lo veo así. Los sieverts, milisieverts y microsieverts sí tienen significado. Son una cantidad de radiación recibida. Como tal puedes hablar de ella en global ("cada radiografía te da 60 microsieverts, cada TAC te da 10 milisieverts") o por unidad de tiempo ("la radiación que recibe una persona en tal sitio en este momento es de tantos milisieverts cada hora").
Dicho de otro modo: los 100 milisieverts de los que habla la noticia sí llevan un valor temporal: supuestamente es lo que habría recibido un bebé a 30 km de Fukushima en los doce días que han pasado desde el terremoto.
OSHA uses REMs (Roentgen Equivalent Man) to define the maximum allowable amounts of radiation exposures in the work place that nuclear power workers, medical technologists, and airline employees should receive in a year and a lifetime. The whole body maximum exposure is 1.25 REM over any 3 month period or 5 REM per year. Restricted areas are considered to be 200 milliREM per hour.
There are three types of radiation coming from Fukushima – Protons (alpha particles), Electrons (beta particles), and Photons (gamma). These particles travel varying distances catching rides in air currents and clouds. Each type of radiation has a different level of penetration into the body; Alpha for instance can be stopped by clothing, Beta by metal, whereas Gamma is difficult to stop. If the radiation is ingested in water or food, then radiation may be absorbed more directly by the internal organs.
Damage to the body is measured by RAD, a measure of the actual amount of radiation absorbed by the ****** Just because a person is exposed to radiation, does not miccionan that it was fully absorbed. 1 REM creates 1 RAD of damage, except in the case of Alpha particles where 1 REM creates 20 RAD of damage
A Sievert (Sv) is used by the medical industry to measure the dose based on the exposure time, volume and part of the ****** Japanese monitoring sites are reporting in Gray (Gy), a measurement of the absorption of one joule of energy in the form of ionizing radiation by one kilogram of matter.
However, the differences between all the radiation dose unit measurements become irrelevant when there is a nuclear disaster like Fukushima because the entire body is exposed and the exposure is constant, not quick zaps from an Xray machine or single injections for a medical procedure. Being able to convert the various units allows an understanding of the dosage from various locations within Japan and around the world.
Effects of Radiation Exposure (in a single day):
0 – 0.25 Sv (0-25 RADs): No observable effects.
0.25 – 0.50 Sv (25-100 RADs): Some nausea and loss of appetite; and blood changes.
0.50 – 1.5 Sv (25-100 RADs): Nausea, vomiting,bone marrow, lymph nodes, spleen damaged.
1.5 – 3 Sv (100-300 REM): Nausea, vomiting, diarrhea, malaise, infection; more severe bone marrow, lymph node, spleen damage; recovery probable, not assured.
3 – 5 Sv (300-600 REM): Above plus hemorrhaging, infection, diarrhea, skin peels, sterility; death if untreated.
5 – 10 Sv (600-1000 REM): Above symptoms plus central nervous system impairment; death expected..
10+ Sv (1000 REM+): Incapacitation and death.
There are three types of radiation coming from Fukushima – Protons (alpha particles), Electrons (beta particles), and Photons (gamma). These particles travel varying distances catching rides in air currents and clouds. Each type of radiation has a different level of penetration into the body; Alpha for instance can be stopped by clothing, Beta by metal, whereas Gamma is difficult to stop. If the radiation is ingested in water or food, then radiation may be absorbed more directly by the internal organs.
Damage to the body is measured by RAD, a measure of the actual amount of radiation absorbed by the ****** Just because a person is exposed to radiation, does not miccionan that it was fully absorbed. 1 REM creates 1 RAD of damage, except in the case of Alpha particles where 1 REM creates 20 RAD of damage
A Sievert (Sv) is used by the medical industry to measure the dose based on the exposure time, volume and part of the ****** Japanese monitoring sites are reporting in Gray (Gy), a measurement of the absorption of one joule of energy in the form of ionizing radiation by one kilogram of matter.
However, the differences between all the radiation dose unit measurements become irrelevant when there is a nuclear disaster like Fukushima because the entire body is exposed and the exposure is constant, not quick zaps from an Xray machine or single injections for a medical procedure. Being able to convert the various units allows an understanding of the dosage from various locations within Japan and around the world.
Effects of Radiation Exposure (in a single day):
0 – 0.25 Sv (0-25 RADs): No observable effects.
0.25 – 0.50 Sv (25-100 RADs): Some nausea and loss of appetite; and blood changes.
0.50 – 1.5 Sv (25-100 RADs): Nausea, vomiting,bone marrow, lymph nodes, spleen damaged.
1.5 – 3 Sv (100-300 REM): Nausea, vomiting, diarrhea, malaise, infection; more severe bone marrow, lymph node, spleen damage; recovery probable, not assured.
3 – 5 Sv (300-600 REM): Above plus hemorrhaging, infection, diarrhea, skin peels, sterility; death if untreated.
5 – 10 Sv (600-1000 REM): Above symptoms plus central nervous system impairment; death expected..
10+ Sv (1000 REM+): Incapacitation and death.
Homer Simpson
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ahora uqe lo dices tb me parece que esa calcu esta mal
sorry...
Noksan
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Asi están las cosas.
http://www.nytimes.com/2011/03/24/world/asia/24nuclear.html?_r=1&partner=rss&emc=rss
The Japanese electricians who bravely strung wires this week to all six reactor buildings at a stricken nuclear power plant succeeded despite waves of heat and blasts of radioactive steam.
The restoration of electricity at the plant, the Fukushima Daiichi Nuclear Power Station, stirred hopes that the crisis was ebbing, but nuclear engineers say some of the most difficult and dangerous tasks are still ahead — and time is not necessarily on the side of the repair teams.
The tasks include manually draining hundreds of gallons of radioactive water and venting radioactive gas from the pumps and piping of the emergency cooling systems, which are located diagonally underneath the overheated reactor vessels. The health warning that infants should not drink tap water — even in Tokyo, far from the stricken plant — raised alarms about extensive contamination.
“We’ve got at least 10 days to two weeks of potential drama before you can declare the accident over,” said Michael Friedlander, who worked as a nuclear plant operator in the United States for 13 years.
Western nuclear engineers have become increasingly concerned about a separate problem that may be putting pressure on the Japanese technicians to work faster: salt buildup inside the reactors, which could cause them to heat up more and, in the worst case, cause the uranium to melt, releasing a range of radioactive material.
Richard T. Lahey Jr., who was General Electric’s chief of safety research for boiling-water reactors when the company installed them at the Fukushima Daiichi plant, said that as seawater was pumped into the reactors and boiled away, it left more and more salt behind.
He estimates that 57,000 pounds of salt have accumulated in Reactor No. 1 and 99,000 pounds apiece in Reactors No. 2 and 3, which are larger.
The big question is how much of that salt is still mixed with water and how much now forms a crust on the reactors’ uranium fuel rods. Chemical crusts on uranium fuel rods have been a problem for years at nuclear plants.
Crusts insulate the rods from the water and allow them to heat up. If the crusts are thick enough, they can block water from circulating between the fuel rods at all. As the rods heat up, their zirconium cladding can ignite, which may cause the uranium inside to melt and release radioactive material.
Some of the salt might be settling to the bottom of the reactor vessel rather than sticking to the fuel rods. But just as a heating element repeatedly used to warm tea in a mug tends to become encrusted in cities where the tap water is rich with minerals, boiling seawater is likely to leave salt mainly on the fuel rods, Mr. Lahey said.
The Japanese have reported that some of the seawater used for cooling has returned to the ocean, suggesting that some of the salt may have flowed out again rather than remaining in the reactors. But clearly a significant amount remains.
A Japanese nuclear safety regulator said on Wednesday that plans were under way to fix a piece of equipment that would allow freshwater instead of seawater to be pumped into at least one of the reactors.
He said that an informal international group of experts on boiling-water reactors was increasingly worried about salt accumulation and was inclined to recommend that the Japanese try to flood each reactor vessel’s containment building with cold water in an effort to prevent the uranium from melting down. That approach might make it a harder to release steam from the reactors as part of the “feed-and-bleed” process that was being used to cool them down, but that was a risk worth taking, he said.
Public alarm in Japan about the crisis increased on Wednesday after officials announced that levels of radioactive iodine had been detected in Tokyo’s tap water.
Recent rains might have washed radioactive particles into the water, as the Japanese government suggested. But prevailing breezes for the past two weeks should have been pushing the radiation mostly out to sea. And until Wednesday, some experts had predicted that radioactive iodine would not be much of a problem, because the fission necessary to produce iodine — which breaks down quickly, with a half-life of just eight days — stopped within minutes of the earthquake on March 11. The antiestéticar is that more radiation is being released than has been understood.
Preventing the reactors and storage pools from overheating through radioactive decay would go a long way toward limiting radioactive contamination. But that would require pumping a lot of cold freshwater through them, which is not easily done.
The emergency cooling system pump and motor for a boiling-water reactor are roughly the size and height of a compact hatchback car standing on its back bumper. The powerful system has the capacity to propel thousands of gallons of water a minute throughout a reactor pressure vessel and storage pool. But that very power can also be the system’s Achilles’ heel.
The pump and piping are designed to be kept full of water. But they tend to leak and develop alternating pockets of air and water, said Mr. Friedlander, who said he had performed maintenance on the systems many times in his career.
If the pump is turned on without venting the air and draining the water, the water from the pump would hit the alternating pockets with enough force to blow holes in the piping. Venting the air and draining the water requires a technician to reach a dozen valves, sometimes using a ladder. The water is removed through a hose to the nearest drain, usually in the floor, that leads to machinery designed to remove radiation from the water.
The process takes a full 12 hours in a reactor that is operating normally, Mr. Friedlander said. But even then, the water in the pipes tends to become radioactively contaminated because the valves that separate it from the reactor are never entirely tight.
It is likely to be an even bigger problem when the water inside the reactor is much more radioactive than usual and is under extremely high pressure, as it has been in all three reactors at the Fukushima Daiichi plant at various times since the earthquake and tsunami.
Japanese government and power company officials expressed optimism on Wednesday morning that the crisis was close to being brought under control, only to encounter two reminders in the afternoon of the unpredictable difficulties that lie ahead.
Fukushima Daiichi’s Reactor No. 3 began belching black smoke for an hour late in the afternoon, leading its operator, Tokyo Electric Power Company, to evacuate workers. No. 3 is considered one of the most dangerous of the reactors because of its fuel — mixed oxides, or mox, which contain a mixture of uranium and plutonium and can produce a more dangerous radioactive plume if scattered by fire or explosions. The cooling system at Reactor No. 5, which was shut down at the time of the earthquake and has shown few problems since, also abruptly stopped working on Wednesday afternoon, said Hiro Hasegawa, a spokesman for Tokyo Electric.
“When we switched from the temporary pump, it automatically switched off,” he said. “We’ll try again with a new pump in the morning.”
http://www.nytimes.com/2011/03/24/world/asia/24nuclear.html?_r=1&partner=rss&emc=rss
The Japanese electricians who bravely strung wires this week to all six reactor buildings at a stricken nuclear power plant succeeded despite waves of heat and blasts of radioactive steam.
The restoration of electricity at the plant, the Fukushima Daiichi Nuclear Power Station, stirred hopes that the crisis was ebbing, but nuclear engineers say some of the most difficult and dangerous tasks are still ahead — and time is not necessarily on the side of the repair teams.
The tasks include manually draining hundreds of gallons of radioactive water and venting radioactive gas from the pumps and piping of the emergency cooling systems, which are located diagonally underneath the overheated reactor vessels. The health warning that infants should not drink tap water — even in Tokyo, far from the stricken plant — raised alarms about extensive contamination.
“We’ve got at least 10 days to two weeks of potential drama before you can declare the accident over,” said Michael Friedlander, who worked as a nuclear plant operator in the United States for 13 years.
Western nuclear engineers have become increasingly concerned about a separate problem that may be putting pressure on the Japanese technicians to work faster: salt buildup inside the reactors, which could cause them to heat up more and, in the worst case, cause the uranium to melt, releasing a range of radioactive material.
Richard T. Lahey Jr., who was General Electric’s chief of safety research for boiling-water reactors when the company installed them at the Fukushima Daiichi plant, said that as seawater was pumped into the reactors and boiled away, it left more and more salt behind.
He estimates that 57,000 pounds of salt have accumulated in Reactor No. 1 and 99,000 pounds apiece in Reactors No. 2 and 3, which are larger.
The big question is how much of that salt is still mixed with water and how much now forms a crust on the reactors’ uranium fuel rods. Chemical crusts on uranium fuel rods have been a problem for years at nuclear plants.
Crusts insulate the rods from the water and allow them to heat up. If the crusts are thick enough, they can block water from circulating between the fuel rods at all. As the rods heat up, their zirconium cladding can ignite, which may cause the uranium inside to melt and release radioactive material.
Some of the salt might be settling to the bottom of the reactor vessel rather than sticking to the fuel rods. But just as a heating element repeatedly used to warm tea in a mug tends to become encrusted in cities where the tap water is rich with minerals, boiling seawater is likely to leave salt mainly on the fuel rods, Mr. Lahey said.
The Japanese have reported that some of the seawater used for cooling has returned to the ocean, suggesting that some of the salt may have flowed out again rather than remaining in the reactors. But clearly a significant amount remains.
A Japanese nuclear safety regulator said on Wednesday that plans were under way to fix a piece of equipment that would allow freshwater instead of seawater to be pumped into at least one of the reactors.
He said that an informal international group of experts on boiling-water reactors was increasingly worried about salt accumulation and was inclined to recommend that the Japanese try to flood each reactor vessel’s containment building with cold water in an effort to prevent the uranium from melting down. That approach might make it a harder to release steam from the reactors as part of the “feed-and-bleed” process that was being used to cool them down, but that was a risk worth taking, he said.
Public alarm in Japan about the crisis increased on Wednesday after officials announced that levels of radioactive iodine had been detected in Tokyo’s tap water.
Recent rains might have washed radioactive particles into the water, as the Japanese government suggested. But prevailing breezes for the past two weeks should have been pushing the radiation mostly out to sea. And until Wednesday, some experts had predicted that radioactive iodine would not be much of a problem, because the fission necessary to produce iodine — which breaks down quickly, with a half-life of just eight days — stopped within minutes of the earthquake on March 11. The antiestéticar is that more radiation is being released than has been understood.
Preventing the reactors and storage pools from overheating through radioactive decay would go a long way toward limiting radioactive contamination. But that would require pumping a lot of cold freshwater through them, which is not easily done.
The emergency cooling system pump and motor for a boiling-water reactor are roughly the size and height of a compact hatchback car standing on its back bumper. The powerful system has the capacity to propel thousands of gallons of water a minute throughout a reactor pressure vessel and storage pool. But that very power can also be the system’s Achilles’ heel.
The pump and piping are designed to be kept full of water. But they tend to leak and develop alternating pockets of air and water, said Mr. Friedlander, who said he had performed maintenance on the systems many times in his career.
If the pump is turned on without venting the air and draining the water, the water from the pump would hit the alternating pockets with enough force to blow holes in the piping. Venting the air and draining the water requires a technician to reach a dozen valves, sometimes using a ladder. The water is removed through a hose to the nearest drain, usually in the floor, that leads to machinery designed to remove radiation from the water.
The process takes a full 12 hours in a reactor that is operating normally, Mr. Friedlander said. But even then, the water in the pipes tends to become radioactively contaminated because the valves that separate it from the reactor are never entirely tight.
It is likely to be an even bigger problem when the water inside the reactor is much more radioactive than usual and is under extremely high pressure, as it has been in all three reactors at the Fukushima Daiichi plant at various times since the earthquake and tsunami.
Japanese government and power company officials expressed optimism on Wednesday morning that the crisis was close to being brought under control, only to encounter two reminders in the afternoon of the unpredictable difficulties that lie ahead.
Fukushima Daiichi’s Reactor No. 3 began belching black smoke for an hour late in the afternoon, leading its operator, Tokyo Electric Power Company, to evacuate workers. No. 3 is considered one of the most dangerous of the reactors because of its fuel — mixed oxides, or mox, which contain a mixture of uranium and plutonium and can produce a more dangerous radioactive plume if scattered by fire or explosions. The cooling system at Reactor No. 5, which was shut down at the time of the earthquake and has shown few problems since, also abruptly stopped working on Wednesday afternoon, said Hiro Hasegawa, a spokesman for Tokyo Electric.
“When we switched from the temporary pump, it automatically switched off,” he said. “We’ll try again with a new pump in the morning.”
Pedro Solves
Madmaxista
En NHk sale ahora el padre de Any Folder, que parece que se la llevó el tsunami, poniendo un ramo de flores en su memoria... solo desean encontrar su cuerpo.. DEP
Homer Simpson
Madmaxista
Nada hombre, lo que menos se espera uno es que una herramienta que supuestamente está para ayudar a entender algo esté mal y te lie más
A girl tweeted in a message translated by ABC: ‘My dad went to the nuclear plant, I’ve never seen my mother cry so hard. People at the plant are struggling, sacrificing themselves to protect you. Please dad come back alive.’
geb
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Sv SÍ es diminutivo de Sievert, y mSv de milisievert, y µSv de microsievert.
Borjita burbujas
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Fijaros lo que acaba de escribir en su blog un español que vive en Japón (vive a 1000 kilómetros de Tokio), yo es que flipo o se está autogestionando de que todo va a ir bien y no tiene ni pu** idea de lo que está ocurriendo.
"La semana pasada tuvimos de “refugiados” en Itoshima a Héctor @kirai y a Carlos @CaDs. A pesar de las estresantes circunstancias que los hicieron alejarse de la vida en Tokio lo pasamos muy bien. Estas fotos son de algunos de los sitios que visitamos en Itoshima y Fukuoka, de los que os hablaré con tranquilidad próximamente. Nuestros amigos ya llevan días en Tokio y la situación por allí se va normalizando :8: . Claro que donde ocurrió la desgracia es en la costa de Tohoku que da al Pacífico, y allí hay todavía mucho trabajo que hacer y mucha gente que ayudar. (Según los antecedentes, esta última frase debe de ser la única de todo el post que vale la pena citar en un periódico.)"
Alojando a refugiados
"La semana pasada tuvimos de “refugiados” en Itoshima a Héctor @kirai y a Carlos @CaDs. A pesar de las estresantes circunstancias que los hicieron alejarse de la vida en Tokio lo pasamos muy bien. Estas fotos son de algunos de los sitios que visitamos en Itoshima y Fukuoka, de los que os hablaré con tranquilidad próximamente. Nuestros amigos ya llevan días en Tokio y la situación por allí se va normalizando :8: . Claro que donde ocurrió la desgracia es en la costa de Tohoku que da al Pacífico, y allí hay todavía mucho trabajo que hacer y mucha gente que ayudar. (Según los antecedentes, esta última frase debe de ser la única de todo el post que vale la pena citar en un periódico.)"
Alojando a refugiados
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