IAEA reviews Japan's nuclear restart process

31 January 2012 A team of international nuclear safety experts has reviewed Japan’s procedure to confirm the safety of its nuclear plants as dire economic conditions grip the country’s power industry. A mission to Japan lasting from 23 to 31 January saw a team of ten experts from the International Atomic Energy Agency (IAEA) and its member states spend time with Japan’s nuclear safety regulator, NISA, which is conducting a two-stage assessment process to ensure nuclear plants have adequate protection against extreme external events. While NISA continues its work to review the preliminary assessments, supported by the Nuclear Safety Commission and the Japanese Nuclear Energy Safety Organization, reactors are still closing one by one for mandatory safety inspections. Currently only three are in operation from a potential operating fleet of 44, not counting the ten Fukushima Daiichi and Daiini units. The preliminary report from the IAEA team to the Japanese government said NISA and nuclear operators had “promptly addressed” emergency safety measures after the accident at Fukushima Daiichi. It contained a range of recommendations to NISA to ensure thorough and lasting improvements in safety are made. The Fukushima accident began after massive tsunami flooding disabled on-site power supplies as well as cooling. The overheating that followed saw three core melts and hydrogen explosions ruin four reactor units. In future, nuclear power plants in Japan and the world over must be better protected from extreme external events like those that hit Fukushima Daiichi – and better prepared to manage such a situation should it occur. Shortly after the accident NISA demanded that Japan’s nuclear power companies report on the safety margins of their power plants under Fukushima-like accident conditions in a ‘primary assessment.’ These documents are to be reviewed by NISA before a reactor can be granted permission to restart at the end of a mandatory inspection outage. No date has been slated for the first restart, and even with the go-ahead from NISA power companies would still require approval from local prefectural governments. Although this is not a legal requirement, the deference traditionally shown by power companies to local officials has become mandatory in post-Fukushima Japan. NISA has so far received 15 primary assessments including one relating to the third reactor at Kansai Electric Power Company’s Ohi nuclear power plant, which was visited by the IAEA team. There they saw the new measures taken by Kansai, including new used fuel pool...
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Extending operating lives of French reactors best option

31 January 2012 Investing in new nuclear generating capacity or any other form of energy would be too expensive and come online too late, France’s state audit office has concluded. Extending the operating lives of its existing nuclear power reactors would be its best option. The Cour des Comptes (Court of Audit), at the request of prime minister Francois Fillon, has released a report into the past, present and future costs of nuclear power in the country. France, the court estimated, has so far spent €188 billion ($246 billion) on nuclear energy. The total cost of building the facilities needed for nuclear electricity generation in France (excluding the cost of constructing the Superphenix commercial prototype fast breeder reactor) is put at €121 billion ($158 billion). Of this, the cost of constructing the country’s 58 second generation power reactors – with a combined generating capacity of 62,510 MWe – is estimated to be €96 billion ($125 billion), while the initial investment needed to build the country’s eight first generation reactors – which have already been shut down and are being decommissioned – is put at €6 billion ($8 billion). The development of fuel cycle facilities – particularly reprocessing plants – cost France some €19 billion ($25 billion). A further €55 billion ($72 billion) has so far been spent on research, while the construction, operation and shutdown of Superphenix cost €12 billion ($16 billion). French power reactors were originally only licensed to operate for 30 years, but they are now subject to a ten-year review to allow for their continued operation. So far, just two reactors – at Tricastin and Fessenheim – have received authorization to continue operating up to 40 years. The court says that if all current units are limited to a 40-year operating life, 22 of the country’s 58 reactors will have to shut down by 2022. Therefore, to keep nuclear’s share of total electricity generation at around the current 75% level, considerable invest in new capacity – equivalent to 11 new EPR units – would be required by then. However, it says that the likelihood of such a program of short-term investment appears “highly unlikely or impossible.” The court suggests that as no decision to invest in new nuclear capacity has yet been made, France will have only two options: to extend the operating lives of its current reactors beyond 40 years or to make rapid and...
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US plant not fazed by loss of power

31 January 2012 Automatic safety systems including diesel backup generators worked smoothly to ensure that Exelon’s Byron plant remained safe and stable despite a loss of offsite power. The operator declared an ‘unusual event’ – the lowest level in the US Nuclear Regulatory Commission (NRC) emergency classification system – at Byron unit 2 at 10.18 am on 30 January. The loss of power was caused by a fault in a transformer in the station’s switchyard, which disconnected it from the grid and triggered the 1105 MWe pressurized water reactor to automatically shut down. The plant’s emergency diesel generators started up and operated as designed, providing power to plant equipment. In normal operation a nuclear plant is self-sufficient in the power it needs to keep itself running safely, but even when the plant shuts down power is still needed to run safety-critical systems such as coolant pumps and electronic controls. This power would usually be drawn from the grid, backed up by emergency diesel generators to guarantee a power supply should offsite power be lost for any reason. Steam was released from the non-nuclear side of the plant as part of the depressurizing and cooling process, as per the design of the plant’s safety systems. Exelon noted that the steam contained “expected” amounts of tritium, although the NRC, which regulates such releases, emphasised that the steam did not present any threat to the public. The NRC is monitoring the situation at the Illinois plant, while plant officials are investigating the equipment failure that triggered the power loss. Byron unit 1 was unaffected and continues to operate at full power. Fuente:...
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El estado actual de Fukushima (Parte II)

31 Enero 2012 Esta entrada es la segunda parte del informe sobre la situación actual de Fukushima (Aquí puedes encontrar la primera parte) escritas por un experto de una central nuclear española que desea permanecer en el anonimato. Amazings.es ha encargado a Francis la labor de edición de su respuesta. Fukushima antes del accidente de Marzo del 2011 Nota de Francis: Para entender lo que sigue conviene recordar que la central nuclear Fukushima Dai-chi (o Fukushima I) tiene 6 reactores, tres de los cuales estaban en funcionamiento el 11 de marzo de 2011, los otros tres estaban en mantenimiento. Los reactores 1, 2 y 3 fueron parados y sus núcleos se fundieron por la falta de refrigeración. El reactor 4 experimentó múltiples incendios porque (como se nos indica más abajo) comparte sistema de ventilación con el número 3 (también lo hacen el 1 y el 2, y los 5 y 6). Los reactores 5 y 6 no sufrieron daños reseñables. Estado actual de las piscinas de combustible Pese a toda la especulación de los medios y el justificado miedo que despertó en su día, las piscinas de combustible se han portado sorprendentemente bien. La que más preocupaba era la de la Unidad 4. Contenía más combustible que las otras unidades porque habían descargado en ella el núcleo de su reactor (desmontado por mantenimiento). La explosión que se registró en el edificio nos puso a todos el corazón en un puño, porque no tenía sentido. Algo muy raro había pasado y en el contexto dramático de aquellos días uno podía esperar cualquier cosa, nada bueno. Hoy ya sabemos qué pasó.  La piscina de combustible de una central nuclear tiene típicamente unos 12 metros de profundidad de agua, de modo que en su posición más alta, un elemento combustible en tránsito (de unos 4 m de largo) tenga al menos 4 metros de blindaje de agua, suficiente para estar en el edificio sin protección alguna; es agua suficiente para que, aún con un núcleo recién descargado, máxima carga térmica, haya mucho tiempo (varios días) desde que se pierde la refrigeración hasta que el combustible queda al descubierto.Pero aún en ese caso, la carga térmica no tiene nada que ver con la de un reactor recién parado. Nada más parar, la carga térmica del núcleo de un reactor nuclear es aún el 7% de su potencia térmica nominal (más de 150 mW...
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Russia commissions fuel storage facility

30 January 2012 Russia will soon start storing used fuel from its RBMK-1000 and VVER-1000 reactors in a new centralized ‘dry’ interim storage facility (ISF) at Zheleznogorsk. The first phase of the facility was recently completed and the first RBMK fuel will shortly be delivered. The first phase of a centralized storage facility has been completed at the Mining and Chemical Combine (MCC) at Zheleznogorsk near Krasnoyarsk, Siberia. ItThe initial stage of the facility – which was commissioned in December 2011 – will be used for storing 8129 tonnes of RBMK fuel from the three power ploants in the country using that kind of reactor: Leningrad, Kursk and Smolensk. The used fuel from these plants is currently stored in on-site water-filled pools, but these are reaching full-capacity. The first used fuel is expected to be delivered to the Zheleznogorsk ISF before the end of March this year. Transported from the plant sites by rail in special containers loaded with about eight tonnes of fuel. It is estimated that the first phase of the facility will be full within eight to ten years. Later, used VVER-1000 fuel from reactors at the Balakovo, Kalinin, Novovoronezh and Rostov plants will also be stored at the facility. Such fuel has already been sent to Zheleznogorsk for storage in water pools. The ISF – measuring some 270 metres in length, 35 metres wide and 40 metres high – will ultimately hold 38,000 tonnes of used RBMK and VVER fuel. The fuel will be stored in the facility for up to 50 years, during which time substantial reprocessing capacity should be brought online. In the long-term, a geological repository for high-level radioactive waste is planned. Rosatom spokesman Sergei Novikov told the Moscow Times that Russia currently reprocesses about 16% of the used fuel it produces annually. However, he said that the country has set a target to reprocess all of the used fuel it generates each year by 2020. Used fuel from smaller VVER-440 reactors at Russia’s Kola plant and the Ukraine’s Rovno plant, as well as the BN-600 at Beloyarsk and from naval reactors is sent to the Mayak Chemical Combine in the Urals for reprocessing. Dry nuclear fuel storage technology is said to have a number of advantages over ‘wet’ storage technology. Dry storage, for example, does not require storage pools and the casks in which the fuel is stored can withstand large...
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