Tihange Nuclear Power Station

The Tihange 1 plant has two separate turbines to produce electricity, the total net electrical power of 962 MW is produced by two 481 MW turbines. These are referred to as Tihange 1N and Tihange 1S, turbogroupe nord (North) and sud (South) respectively.

Various weather conditions have been analysed including rain, seiches, tsunamis, floods, earthquakes, wind, tornados, lightning, snow, hail, extreme temperatures, cyclones, sandstorms and waterspouts.[15]

The Tihange plant was originally designed for 1000-yearly floods. After Fukushima the design base of the plants was increased 10,000 yearly floods by building a flood wall around the plant.[15]^: 91

Earthquakes were also considered. The historically most significant earthquake for Tihange was the one at Tienen in 1828 with a magnitude of 5.4 on the Richter scale. This earthquake resulted in horizontal ground accelerations of up to 0.1g [15]^: 55 and formed the original design base for Tihange 1. During the first periodic safety review of the unit after 10 years of operation the design base was increased to 0.17g, this corresponded to the design base of the new Tihange 2 and Tihange 3 units.^: 50 After the Fukushima Daiichi nuclear disaster probabilistic safety studies performed by the Royal Observatory of Belgium predicted earthquakes with peak ground acceleration of up to 0.21g every 10,000 years.[15]^: 52 The design was subsequently analysed and upgraded for earthquakes up to 0.3g.[15]^: 78

Besides regular primary level safety systems, in common with most nuclear power plants in the world, Tihange has secondary level safety systems that can autonomously keep the power plant safe during large external accidents such as the crash of an aircraft, external explosions or loss of the primary level.[15]^: 14[15]^: 14 The primary level systems have two or three redundant trains of safety.^: 26–29 The secondary level systems are 3x50% or 2x100%.[15]^: 30–33 and have their own heatsink separate from the primary heatsink. The primary heatsink is the Meuse river while the secondary heatsink is water from underground water tables.[15]^: 29

Nuclear plants are designed with multiple physical barriers to keep fission productions from escaping into the environment. In the case of a pressurized water reactor there are three barriers: the fuel cladding which surround the fuel pellets, the primary circuit which houses the fuel rods and finally the containment building in which the primary circuit is built. In Belgium it was decided to add an extra barrier, a so-called double containment.[16] The primary containment of the containment building, is a pre-stressed concrete cylinder with steel liner. It is surrounded by a secondary containment made of 1.2 to 1.3m thick reinforced concrete. The space between both containments is kept at sub-atmospheric pressure and filters are used to filter potential leaks of the primary containment.[15]^: 14

In answer to a question of die Grünen in the Bundestag, the German parliament, the German government replied that the Belgian nuclear power plants do not have filtered containment venting systems installed. In German nuclear power plants these were already built in after the nuclear disaster in Chernobyl in 1986. Other countries followed this example, latest after the Fukushima nuclear disaster. This kind of system allows for the containment pressure to be relieved in the event of a severe accident. The non-condensable gases that cause pressure within containment to rise are released through a stack (or chimney) via a filtration system that removes large quantities of fission products from the effluent.[17][18][19][20][21][22]

As part of the stress tests following the Fukushima incident, this issue had already been identified to be included in the stress-test action plan (BEST). All units will have functional containment filter venting systems by 2017.[23]

Every unit has at least one steam driven feedwater pump which can supply the steam generators with water to cool down the reactor. These turbine driven pumps can cool down the plant even when no electrical power is available to power the motor driven feedwater pumps during a station blackout like the Fukushima Daiichi nuclear disaster.[15]^: 147 In a boiling water reactor, like those in Fukushima, the heat removal capacity of the pumps is limited as the steam that drives the turbines is radioactive and thus has to be stored.[24] This is not the case with a PWR due to the use of steam generators. Steam can simply be removed via a chimney. Autonomy is merely limited by the supplies of water on site. The initial supply of water in the reservoir is sufficient for almost 24 hours. After those 24 hours mobile pumps are used to fill up the reservoir.[15]^: 147

Each unit has its own cooling tower: the cooling tower of Unit 1 has a height of 159.8 metres, that of Unit 2 measures 159.02 metres and that of Unit 3 159.27 metres. Every unit has also its own chimney, which are in opposite to that of other nuclear power stations realized as rooftop guyed steel chimneys: The total height of the chimney of Unit 1 is 161.18 metres, that of Unit 2 161.21 metres and that of Unit 3 160.79 metres.

Greens member of the European Parliament Rebecca Harms has called for the decommissioning of Belgium's oldest nuclear reactor, Tihange 1, as it no longer meets international safety standards.

Harms’ demand coincides with the publication of a new study on the risks of the continued operation of Tihange 1. The author of the study is Prof. Manfred Mertins, an expert in nuclear engineering and former member of the German Nuclear Safety Authority. He presented the findings at a news briefing in the European Parliament. The academic came to the conclusion that the continued operation of Tihange 1 due to “outdated reactor design, inadequate safety management and the accumulation of frequent unplanned events represents a potential danger for the site and its surroundings.” It was particularly critical “that the results of international tests and current safety standards are not adequately taken into account.” [31]

On 15 March 2016, the federal government of Belgium decided 140 soldiers would guard the nuclear sites.[32] In late 2015 it was already decided a specially trained department of the federal police would guard the nuclear sites.[33] After the 2016 Brussels bombings on 22 March the nuclear powerplants of Tihange and Doel were preventively evacuated, as per standard procedure if the threat level in Belgium reaches level 4. The powerplants continued running with a minimum amount of staffing.[34]

In February 2017 the Frenchman Jean-Philippe Bainier was installed as the new CEO of Tihange in order to restore confidence in the safety culture at the plant. He succeeded Johan Hollevoet, who was in charge from September 2016 at the Tihange nuclear power station. Together with FANC a new action plan was made in order to raise the safety culture level. 'Safety is my first priority', insured the Engie Top-woman Isabelle Kocher: 'On the safety of our people, of the people living near the power plants and the environment is not to bargain.' In the action plan the responsibilities were more clearly defined and the company was willing to will appeal more independent expertise. The action plan includes a total of 314 actions, of which 142 were already carried out. The intention was that around August 2017 the action plan was to be completed.[35]

In September 2018 during a planned inspection by the exploitant Engie Electrabel decaying concrete was found in the bunker-buildings of Doel 3 and Tihange 3, where the emergency-systems are located. Only after further investigations and when FANC gives permission, will the reactors be restarted. According to FANC the decay of the concrete had no impact on thee direct environment of the reactors. The restart of reactor Doel-1 and Doel-2 was already earlier postponed from October to December 2018 because needed maintenance.[36] After inspection also in Doel-4 and Tihange-2 concrete decay was found in the ceilings of the buildings.[37]

On 24 September 2018, Minister Marie-Christine Marghem of Energy, mentioned during a press-conference that she would contact the Netherlands, France and Germany, to help Belgium with extra capacity for electricity. Only one nuclear power station was available until November, because the repairs of the concrete ceilings does take too much time. Engie Electrabel was criticized because the firm had waited too long to communicate the problems with the concrete in the buildings.[38]