Faulty valves in new-generation EPR nuclear reactor pose meltdown risk, inspectors warn

safety relief valves

A 2011 file photo showing the construction site of the third-generation European Pressurised Water nuclear reactor (EPR) in the French northwestern city of Flamanville Photo: AFP

Nuclear safety inspectors have found crucial faults in the cooling system of France’s flagship new-generation nuclear power plant on the Channel coast, exposing it to the risk of meltdown.

The third-generation European Pressurised Reactor currently under construction in Flamanville is the same model that Britain plans to use for two new plants at Hinkley Point in Somerset.

State-controlled nuclear giant Areva is responsible for the design and construction.

France’s nuclear safety watchdog found “multiple” malfunctioning valves in the Flamanville EPR that could cause its meltdown, in a similar scenario to the 1979 Three Mile Island nuclear accident in the US.

The inspectors listed the faults in a damning presentation obtained by Mediapart, the investigative French website.

safety relief valves

A 2011 file phot showing a technician removes protective gear as he leaves the room with the basin holding nuclear fuel elements at the operating power plant in Flamanville (AFP)

This is the latest setback for what is supposed to be France’s atomic energy showcase abroad, following the revelation last month that its steel reactor vessel has “very serious anomalies” that raise the risk of it cracking. The vessel houses the plant’s nuclear fuel and confines its radioactivity.

The findings were listed in a presentation by the French Institute for Radiological Protection and Nuclear Safety (IRSN) to France’s top nuclear safety regulator (ASN).

The watchdog reportedly cited “multiple failure modes” that could have “grave consequences” on the safety relief valves, which play a key role in regulating pressure in the reactor.

Owned by state-controlled French utilities giant EDF, Flamanville lies close to the British Channel Islands and about 150 miles from the southern English coast.

Designed to be the safest reactors in the world and among the most energy-efficient, the €9 billion (£6.5 billion) EPR has suffered huge delays in models under construction in France, Finland and China.

It is now due to enter service in 2017, five years later than originally planned.

safety relief valves

Flamanville during its construction (AFP)

In April, it was revealed that excessive amounts of carbon in the steel in the top and bottom of the reactor’s vessel, which forms a shell around it, could cause cracks which could prove disastrous, as the vessel cannot be replaced during the lifespan of the reactor.

The faulty safety relief valves are situated on the pressuriser, which regulates the high pressure within the primary circuit where water cools the nuclear fuel by releasing steam when necessary.

The failure of a pilot-operated relief valve in the primary circuit was a key factor in the partial meltdown of a reactor at the Three Mile Island plant in the US in March 1979, and which led to the halting of America’s civil nuclear power programme.

In that accident, nuclear reactor coolant escaped through a valve that was stuck open, sending the reactor into partial meltdown.

safety relief valves

The machinery room in Flamanville (AFP)

At Flamanville, IRSN noted “opening” and “closing” failures concerning the pilots that operate the safety valves and “risks of fluid leaks” of the reactor coolant. It warned that the multiple faults could have “grave consequences”.

On Tuesday, IRSN confirmed tests conducted by EDF showed “difficulties in opening and shutting valves”.

But it played down the gravity of the findings, saying : “For now, one cannot conclude it is serious as we haven’t fully judged the quality “of the valves” – a view it will announce this summer.

“We are examining dossier handed in by EDF with a view to starting up the EPR. There are remarks on all subjects. It’s classic,” said Thierry Charles, deputy director general of IRSN.

Last week, the French government announced Areva NP, the nuclear reactor arm of state-controlled Areva, is to be sold to EDF, its former client which also operates all of France’s 58 nuclear reactors.

The move followed Areva’s announcement in March that it had racked up record losses in 2014 of €4.8 billion.

EDF is in the final phase of negotiations with the British government on building the two Hinkley plants in Britain, which in February it said would be “possible in the next few months”.

The European Commission estimates the development will cost £24.5 billion.

Sourced by ekomeri.com

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Comments (1)

  1. :

    RG, I just got back from Siberia (Steppes, not Taiga or Tundra). You can send me there any time.Nuclear power is all the good thgins they say about it. It is also all the bad thgins they say about it. The problem is humans. They don’t follow their own (e.g. construction/safety)rules usually for money reasons, then they lie about it, again usually for money reasons and face saving reasons.(BBC, that seems to be your take on the whole world and you are right, of course).

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