Obrigheim Nuclear Power Plant

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Decommissioned Reactors ( gross ):

The decommissioned nuclear power plant Obrigheim (KWO ) is located in Obrigheim am Neckar in the Neckar -Odenwald -Kreis and is equipped with a leichtwassermoderierten pressurized water reactor. The gross electrical output of the power plant was 357 MW. On September 22, 1968, the reactor went critical for the first time. The plant was finally shut down on 11 May 2005.

History

Planning

On 5 May 1955, the Federal Republic of Germany was superior with the entry into force of the Treaties of Paris and was allowed to re-engage with the peaceful use of nuclear energy. In particular, the further away from the Ruhr -lying states of Bavaria and Baden- Württemberg were interested in the use of nuclear energy for electricity generation. Already in 1957, the Association of nuclear power Stuttgart ( AKS ) was founded in Baden- Württemberg, chaired by the former Baden -Württemberg's Minister of Economic Affairs Hermann Veit took over. The aim of the working group should be the planning and construction of a nuclear reactor in Baden- Württemberg. To this end, they had caught up with four offers from British and U.S. companies. Particularly interested they were in the British gas-cooled Calder Hall reactor.

In the spring of 1959, the AKS opted for a most exotic of the power reactors, the organic moderated and cooled reactor ( Omre ). Developed by the American company International Atomics reactor was offered in collaboration with the German Demag. At this time there were no experiences about the Omre in the upper power range. On 21 October 1960, the AKS was transferred to the nuclear power plant Baden- Württemberg mbH planning ( KBWP ). The KBWP commissioned in early 1961, the BBC in Mannheim with the construction of the conventional power plant part and put as the site for the 150 - MW plant, an area on the left bank of the Neckar north of the community Obrigheim fixed.

Once you had tried twice in the EURATOM to financial support, kicked in the USA with the organic -cooled demonstration reactor nuclear power plant in Piqua, Ohio technical problems. In particular, the deposition of organic matter on the fuel rod surface, the so-called fouling, as well as the thermal and radiolytic decomposition of the organic mixture of diphenyl / terphenyl, causing considerable embarrassment. The end of 1962 the project was finally abandoned Omre and they decided on the tried and true in the U.S. light-water reactor. Then presented the AEG in cooperation with General Electric and Siemens in cooperation with Westinghouse offers for a light water reactor. The AEG provided detailed documentation for a boiling water reactor, while the Siemens - Schuckert presented a pressurized water reactor. In the summer of 1964, KBWP chose the Siemens pressurized water reactor. The offer was most convincingly with a guaranteed net capacity of approximately 283 MW.

Construction

On July 16, 1964 7 Atomic Energy Act has been applied for the nuclear license according to §. Requirement for the license to the protection of the population was to the effect that even for the design basis accident (GAU ) would not be necessary to evacuate. The full pressure containment of the Siemens system was evaluated with respect to the GAU very positive. In the fall of 1964, the nuclear power plant Obrigheim GmbH ( KWO) was founded as a developer and future operator with 13 shareholders. As main partner acted energy supply Swabia with 35% and bathing station with 28%. The share capital amounted to about 100 million German marks. The supply agreed by Siemens and KWO was signed on 12 March 1965. Immediately, the extensive construction work in Obrigheim. The weather conditions in 1965 were anything but favorable. In addition, production difficulties led to delays of individual components and aggregates, which could be collected due more flexible way of working and speedy installation on the part of e- technology, however. So construction could be started with the commissioning of individual plant parts after only 28 months.

Individual components were modified during construction for ease of manufacturing. Thus, the wall thickness of the reactor pressure vessel was reduced by more realistic interpretation. Nevertheless, a thermal shield was designed for this pressure vessel yet, which related in later pressurized water reactor plants ( Stade, Biblis ).

Although KWO closely oriented to the American Yankee Rowe nuclear power plant, some key improvements over the Westinghouse plant were made ​​by Siemens yet. So one during operation walkable full pressure containment ( containment ) was built. Other changes related to the primary circuit (wave- sealed pumps instead of canned motor pumps) and the reactor internals and the core control ( control rod fingers, slow regulation by boric acid). Steam turbine, turbo generator and control systems were designed siemens own. The high-voltage switchgear were taken in May 1967 in operation. In August 1967, the assembly of the primary circuit was completed with the pressure test.

The first to fourth hot trial run with heating by the main coolant pumps took place from November 1967 to February 1968. This extensive vibration tests and trials on the reactor control and protection system at the reactor were performed. The first core loading was completed on schedule and without any difficulties. With the new systems had yet to be collected experiences. Due to vibration problems in the thermal shield the nuclear commissioning delayed. Thereafter, the reactor pressure vessel was discharged, and again checks the internals. After calibration of the reactor instrumentation and setting of the reactor protection system of the reactor on 14 June 1968 for the first time equipped with fuel and poisoned with boric acid. After a subcritical hot test operation was performed and then discharged to the reactor. End of June 1968, the process computer system has been put into operation and the software checks. In July and August 1968, the reactor internals and the pressure vessel for nuclear operation were released and taken the emergency cooling system.

Prior to the second loading of the reactor core irradiation samples were incorporated in the boiler plant material between the thermal shield and the reactor pressure vessel wall in order to examine the subsequent Werkstoffversprödung by neutrons. After the second loading, the reactor was initially boric acid kept in a subcritical state. He-3, two counter tubes monitored multiplication. To set the external measuring chambers two polonium -beryllium sources were used.

To make the reactor critical, that is, to initiate the chain reaction, the controls were extended immersion depth up to one-third and the boric acid concentration decreases continuously in the coolant by increasing feeding deionized water. On September 21, 1968 began with a boron concentration of about 3000 ppm with the hourly reduction in the concentration of about 180 ppm.

Operation

On 22 September 1968 morning at 5:45 clock, the reactor of the KWO was first critically at a boron concentration of 1,714 ppm. The first synchronization of the turbo generator, and the first power supply of KWO in the grid took place on October 29, 1968 at 18:45 clock. The commercial power operation began on 31 March 1969. Shortly after the commissioning of the power plant were recorded in 1969, plans for a second power block, but which were discarded in 1977. In late 1979, the net electrical output of 280 MW was increased to 328 MW. In the meantime, increasingly appeared leaks on the U-tubes of the steam generators from Inconel 600 due to stress corrosion cracking. Already in 1971, joined a massive Heizrohrschaden on with a leak rate of 3,000 liters per hour, which resulted in a reactor scram. Therefore, in 1976, two new steam generator U- tubes made of Incoloy 800 were delivered. However, these were not installed until 1983, after too many tubes had been plugged. A further increase to 357 MW was made for improvement of the turbine blading in 1984.

In the field of radiation and fire protection has seen many improvements. For additional radiation shields were in the first months of operation, and built the fire, especially in the nuclear field retrofitted. Until 1973 there was a marked increase in radioactivity in the primary circuit due to a deposition of activated corrosion products (eg cobalt -60). To raise the pH in the reactor coolant therefore lithium hydroxide was added in 1971, which proved to be even for the next pressurized water reactors Kraftwerk Union. The radioactivity levies on air and water had to be improved. By installing additional filter, especially for radioactive iodine absorption filter, improved water chemistry and various seals on fittings and assemblies, the release of radioactivity to the environment could be significantly reduced.

Load analyzes showed that some components and measuring equipment to the requirements of the design basis accident (GAU ) is not quite enough. The boiler had additional support with angled and other important measurement, control and regulation systems are replaced with more robust parts. In order to relieve the emergency power supply, the safety injection aggregates were additionally equipped with diesel engines.

The early eighties, the establishment of an emergency system against external influences was supported by the Nuclear Safety Commission. Then an emergency building was completed in 1982. The secured against earthquakes, explosions and plane crashes emergency building includes additional emergency power and Notspeiseaggregate and an emergency control room.

A legal opinion by Prof. choice presented in 1989, the lack of permanent operating license of a nuclear power plant Obrigheim fixed. This led a year later to the temporary closure of the power plant. In 1991 the plant was started up again. The lack of permanent operation license was granted in 1996 by the Ministry for the Environment, Nature Conservation and Transport Baden- Württemberg. Nevertheless, the fierce controversy in politics and the public continued.

1999 run as wet storage of spent fuel interim storage facilities for 980 with about 286 tonnes of heavy metal weight was put into operation. To replace this, EnBW Kernkraft GmbH has 440/84 applied for the construction of a dry storage facility for the storage of a maximum of 342 spent fuel assemblies in a total of 15 transport casks of the CASTOR. The camp will be set up in a 35 m long, 18 m wide and 17 m high hall of reinforced concrete with a wall thickness of about 85 cm and a slab thickness of about 55 cm. The pre-planned by EnBW storage containers from individual Betonumhausungen was withdrawn after safety concerns of the Federal Office for Radiation Protection ( BfS). As part of the approval procedure, the two -month public interpretation of the documents took place in the summer of 2008, with about 900 people have raised objections.

In the 37-year long period of operation of the reactor 267 reportable incidents had occurred.

Closure

2000 reached the then red - green government a consensus, which provides a long-term phase-out of nuclear energy. Obrigheim should have been turned off by this so-called nuclear consensus in December 2002. In order to delay the shutdown of the KWO, requested the operator of the nuclear power plant, EnBW, on 26 September 2002, the transfer of a residual current amount of 15,000 gigawatt hours of Neckarwestheim -2 on Obrigheim. Finally, a residual current transfer in the amount of 5,500 gigawatt hours of Philipsburg -1 was approved by KWO by the Federal Environment Ministry, thus increasing the duration of the KWO extended by about two and a half years. The duration of Philipsburg -1 decreased it only slightly according to the higher net output of the plant. Regardless of the transfer residual amount of current the latest possible closure of the KWO until 15 November 2005, agreed by law.

During the phase-out of nuclear power in Germany, the plant was shut down on 11 May 2005 at 7:58 clock. The demolition began in late 2007, the complete dismantling of the plant should be completed in 2020 and will cost around half a billion euros at present. Is funded through the dismantling financial reserves which the operator has claims to be made ​​in the amount of the estimated costs. After reduction to the spent fuel, which is currently still in a wet storage of the power plant, arrive in a new interim storage at the power plant site.

End of 2011, residents complained for lack of transparency against the dismantling of the reactor and passed in April 2012 an urgent application for a break -in. The actions were dismissed in September 2012, as the opinion of the Baden-Württemberg Higher Administrative Court ( VGH ) is a faster dismantling überwöge the interests of the plaintiff.

Power line to the power plant

The electricity produced in nuclear power plant Obrigheim was removed via a single high- voltage line to the substation Hüffenhardt. This has four circuits: two 220 kV and two for 110 kV, the circuits for 110 kV on the masts, which have three crossbars arranged in a level arrangement on the lowest crossbar and the circuits for 220 kV to the top two crossbars are.

A special feature of this high-voltage line is that isolators are mounted between the conductor cables in the span between the masts to prevent short circuits and arcing in high winds.

Meteorological masts

The complex originally included two meteorological masts, both of which are designed as guyed steel framework masts. One of the masts was built east of Asbach, south of the industrial area TECHNO 1977/78. In spring 2001, this 169 meter high mast was demolished using explosives. In its place now stands a mobile tower in precast concrete construction.

The second 99 -meter high mast next to the power plant was built in 1962 by order of the State of Baden -Württemberg by the State Institute for Environment, Measurements and Nature Conservation ( LUBW ) and is still in operation. Measurement results are documented online at the LUBW homepage.

Others

Although the nuclear power plant is named for the village Obrigheim, it is on the boundary of the hamlet Obrigheimer mortar stone. The plant went on line in 1968, mortar stone was, however, incorporated only in 1971 after Obrigheim and made up to this point an independent municipality.

Data of the reactor block

The nuclear power plant Obrigheim has a power block:

39141
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