An emergency building at the Tihange 3 plant has construction defects: is there a risk?

The bunker next to reactor number 3 at the Tihange NPP was poorly built. Engie Electrabel confirmed this Thursday the discovery of anomalies in the reinforcement of reinforced concrete present since the construction of the building. "The badyzes are in progress and no conclusion can be made at this stage," says the operator. Is there a risk to the stability and safety of the plant?

The discovery of these anomalies comes as the planned reactor overhaul is underway. Engie Electrabel has launched a preventive inspection and repair program for all its units following other abnormalities observed in the concrete in an annex building of Doel 3. At Tihange 3, Electrabel also found , in April 2018, a deterioration of the concrete at the ceilings of the premises housing " the exhaust nozzles of the vapor escapement valves "

" The equipment in this bunker must be available in a nuclear accident and with the deterioration of the concrete just discovered, the integrity of the building could be compromised "says Simon Coenen, expert at the Federal Agency for Nuclear Control

Presumably, these pins moved when the concrete was poured in the period of construction

A repair program was directly put in place. During these inspections, the teams proceeded to stripping the damaged areas. This stripping revealed anomalies in the reinforcements of the reinforced concrete present since the construction of the building. It appears that reinforcement elements of the concrete slab on the ceiling are not positioned strictly as on the plans. " Presumably, these pins moved when the concrete was poured in the period of construction ", explains the energy specialist. Engineers at Engie Electrabel are currently working on " badyzes and calculations under the control of independent experts ".

These calculations are to determine "the impact of the non-conforming positioning of pins in the construction plan in the event of an external event such as a plane crash ". This file will then be given to the Federal Agency for Nuclear Control, which will take a position. " The badyzes are in progress and no conclusion can be made at this stage ," the statement said.

Engie Electrabel recalls that nuclear safety is his " top priority ". The design of the Belgian plants was described as " particularly robust " during the European stress tests. The margins that were applied during the construction of the units are more important than in neighboring countries, says the company. Engie Electrabel points out that in case of doubt, the operator puts the unit on standstill and the restart must be authorized by the FANC.

This emergency building must be able to withstand a fall

For Doel 3, during inspections during the planned shutdown of the reactor, Engie Electrabel's crew had detected that the concrete ceiling of the building attached to the reactor building had to be repaired. [19659003] This bunker is the emergency building, where everything is managed in case of disaster like Fukushima. This building houses 2nd level backup systems, used only in case of problems with the 1st level systems. Analyzes have shown that in these facilities located in the non-nuclear part, the state of the concrete can be weakened by hot and humid conditions. However, security requirements include that these bunkerized buildings must withstand an external event, such as a plane crash. The necessary actions are in progress and the restart of Doel 3 is scheduled for August 1st. The units of Doel 1, Doel 2 and Tihange 1 have a different design than the other units. The question of concrete does not arise, says Engie Electrabel.

Four out of seven plants stopped or under review

" If it is true today and I confirm that there is no risk because the plant is shut down, for years, this plant has turned with a huge risk for the workers but also for the population. that's unacceptable ", reacts Jean-Marc Nollet, MEP Ecolo.

In total, four reactors out of the seven in Belgium are therefore at a standstill. Engie Electrabel is nevertheless rebaduring. " This is necessary, because we carry out a whole series of works of maintenance, in order to maintain the highest level of safety of our power stations, and in accordance with the rules and the standards which are imposed on us "explains Anne-Sophie Huge, spokesperson for Engie Electrabel. But four stationary out of seven, is not it too much? " It is not four out of seven that we must remember, because there are units that are under revision ", replies Anne-Sophie Huge.

The cost of the interruption of the power plants

But of the stationary plants, this has a cost: approximately 250 million euros. There is of course the work and the loss, since it is energy that is not sold. " It does not directly affect the consumer We have announced to the market that some units would be unavailable, but I repeat again: it is safety that prevails ," said the spokesperson

Engie says he can do the necessary repairs by the end of September. In any case, the green light from the Federal Agency for Nuclear Control will be essential to revive Tihange 3.