naima escribió:BeRReKà y Moski,
el combustible de los reactores seguirá generando calor durante años, pero a estas alturas se produce a un ritmo muy bajo.
Sería viable sepultarlos?
Siempre será mejor intentar sacar el combustible de las vasijas.
En Chernobyl el combustible ya había fundido, habiendo ocurrido lo peor se limitaron a enfriar para sofocar el incendio y detener la salida de humos para a continuación sepultar. Si sepultamos Fukushima al estilo Chernobyl sin extraer antes el combustible, puede terminar fundiendo dentro.
Cuando yo hablo de sepultar Fukushima es siempre previo sacar el combustible y para ello hay que enfriarlo. Todo con la finalidad de ahorrarse la limpieza y detener la contaminación exterior. Pero si puedes limpiar, mejor eso que sepultar.
La otra opción, la que yo creo mejor dada la situación y la opción de la que hablo por defecto es cubrir los reactores ahora, pero no como Chernobyl, se trataría de aislarlos para detener la liberación al exterior de contaminantes pero permitiendo trabajar dentro
Se confirma… la cosa no pinta nada bien.
FOCUS: Several months may be needed to cool down crippled Fukushima reactors
By Atsuko Kawaguchi
TOKYO, April 1, Kyodo
Work to regain control of Tokyo Electric Power Co.'s crippled Fukushima Daiichi nuclear power plant has hardly been making headway, even showing signs it may turn out to be a long-haul battle. Managing to bring the reactors to a stable condition is essential in order to curb the proliferation of radioactive materials that have been a source of concern for the nation.
In reaching that goal, three steps are vital -- removing contaminated water at the turbine buildings of the Nos. 1 to 4 reactors, followed by bringing the cooling systems into operation and then cooling down the reactors for shutdown.
Experts anticipate complicated challenges, suggesting it may take months to reach the goal of cold shutdown.
The top priority at this moment is the handling of a large volume of water containing radioactive substances. Bundles of power system devices are located in the basements of the turbine buildings which have remained filled with such water. This is one of the most critical locations in restoring power necessary to cool down the reactors and spent fuel pools in a stable manner.
Unless the contaminated water is removed, work cannot be implemented efficiently.
A large volume of contaminated water has also been found in trenches outside the turbine buildings. Placing priority on disposal of water inside the buildings, rather than the trenches, TEPCO has initiated work to move the water to equipment called condensers but with at least one already filled up, additional steps to move the water from it to a tank are necessary to make room, costing TEPCO more time and effort.
Furthermore, it remains unknown how much water there is in all, making it difficult to estimate if the tanks available around the buildings are enough. Various proposals have been floated to accommodate the water such as getting a large tanker vessel, excavating a huge hole in the ground and installing new tanks. None, however, appears to be a promising idea for implementation.
Hidehiko Nishiyama, a Ministry of Economy, Trade and Industry official in charge of nuclear safety, suggested Thursday the idea of recycling the stagnant water, saying, ''I wonder if we can move water (into the reactor) to circulate it for cooling down.'' Whether it is a feasible idea remains unknown.
Hiroaki Koide, assistant professor in reactor engineering at Kyoto University, said ''transportation by tanker is realistic'' but ''it would probably have to be done repeatedly and require months.''
Meanwhile, off-site power has been connected to the Nos. 1 to 4 reactor buildings and light has been restored at their central control rooms. If the contaminated water is removed, power system devices can be reinstated, paving the way for the next step. What has to be achieved foremost in this context is to bring internal cooling systems on-stream that will make it possible to cool the reactors and spent fuel pools stably.
This process, too, is shrouded in uncertainty. TEPCO says it has been unable to confirm directly what conditions are like in the basements of the turbine buildings but it is believed many devices have been immersed in water and therefore compromised.
TEPCO says damaged devices will be fixed with new parts and by rebuilding power systems it will continue work toward rebooting cooling systems. But it is believed that rapid restoration is unlikely for those devices affected by a large volume of water.
Apparently aware of such a possibility, TEPCO is also considering restoring the cooling systems through another method such as using pumps to feed seawater, in addition to work centering on restoring power at the turbine buildings.
Yet it also remains unpredictable if the cooling systems would work smoothly after power is restored. There remains a strong possibility that damage has been done to piping and pumps. Considerable time would have to be spent for their replacement and inspection.
Kenji Sumita, professor emeritus in nuclear engineering at Osaka University, said until the cooling systems are reactivated ''spraying water has to continue so that the temperature may not rise.'' A balancing act will likely be required as dousing the reactor and fuel facilities could increase the amount of contaminated water.
''If water is sprayed continuously, the heat from radioactive decay should gradually drop,'' Sumita said. ''At this stage, this type of stopgap arrangement has to be made.''
''It is necessary to anticipate that at least several months would be needed'' to achieve cold shutdowns of the reactors, he said.
At a news conference on Thursday, top government spokesman Yukio Edano said, ''We want to present a roadmap (for containing the crisis) as soon as possible but we are not yet at the stage to make such a report in a responsible manner.''
No clear chart appears to have been mapped out as officials still struggle their way toward restoration.
==Kyodo
No quiero ser alarmista, pero ya pueden darles buenos trajes a los trabajadores, e ir pensando que por el camino va a caer alguno por desgracia, eso sin contar, que tendrán que buscar a tropecientos voluntarios o no voluntarios, para solucionar el problema.
Un Saludo…
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