Tricastin (France)

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4 * 900 MW PWR units constructed by Framatome

Incident at Tricastin: 2008-07-07

SOCATRI is a a subsidiary of EURODIF SA/ AREVA is a Uranium Recovery and Cleanup Facility (IARU). It is located on the Tricastin nuclear site at Pierrelatte, in the Drôme region (France)

A storage tank at the uranium-bearing waste treatment facility of the SOCATRI plant on the Tricastin site overflowed, leading to a uranium solution leak.

In its capacity as technical support organisation for the French nuclear safety authorities, the IRSN took immediate action, rushing in a fast response team to the site. A team was quickly set up at the IRSN emergency response centre to take stock of the situation and make proposals for monitoring measures to be taken to supplement the water restriction measures already taken by the Prefect.

An initial groundwater monitoring plan was set up on July 8, 2008. On July 9, the plan was then extended to cover water from three lakes – "Le Trop Long", "Girarde" and "Lac du Devès" – and from the rivers Gaffière, Lauzon and Mayre-Girarde located to the south of Tricastin. Meanwhile, the IRSN took samples of sediments, plants and fish. The results of environmental monitoring measurements taken by the IRSN and SOCATRI between July 8 and July 22, 2008, were regularly posted on our website and could be consulted via interactive maps.

Following the opinion of the French French Nuclear Safety Authority ASN, the Prefects of Drôme and Vaucluse lifted the water restrictions they had imposed earlier in the month. On the evening of July 21, after examining all the measurements taken in various compartments of the environment (surface water, groundwater, lake water, sediment, water plants and fish), the IRSN recommended lifting all restrictions on water use, subject to the implementation of an extended monitoring plan.

Facilities in Tricastin

plantreactor typconstruction startoperation startshut down
Level 2 incident on INES scale concerning back-up diesel generators at Tricastin nuclear power plant

"ASN has rated at level 2 on INES scale an incident reported by EDF licensee on February 16, 2011 concerning back-up diesel generators at Tricastin NPP.

The failure of a back-up diesel generator has been highlighted on 7 February 2011 during a periodic test conducted at an EDF NPP. According to a preliminary analysis undertaken by EDF and its supplier the failure is due to a premature degradation of the bearing bushings. In the French NPP fleet, 26 back-up diesel generators are equipped with this type of bearing bushings which are therefore potentially sensitive. Only units 3 and 4 of the Tricastin NPP have all back up generators equipped with this type of bearing bushings. Therefore, on this site, the anomaly is rated by ASN as incident Level 2 on the INES scale.

For the rest of the concerned reactors, at least one back-up generator, either in the reactor or on the site, is equipped with a different brand of bearing bushing which do not have this defect. The anomaly on these sites has been rated by ASN at level 1 on the INES scale.

ASN has asked EDF to submit a corrective action plan. The first EDF proposals have been submitted to ASN. ASN, with the support of IRSN, is currently assessing these proposals which include the installation of new bearing bushings and the implementation of a new operating procedure for the diesel generators involved."



The French Nuclear Safety Authority (ASN) was informed by France’s Electric Power Company (EDF) about an incident that occurred on 8 September 2008 at 10:30 am while handling fuel during unloading operations on the Tricastin 2 reactor.

The nuclear reactor core consists of 157 fuel assemblies, each assembly containing 264 fuel rods. The reactors must be periodically shutdown and unloaded in order to replace fuel.

During this operation, the reactor vessel cover and the upper internal holding structures are removed in order to be able to access the fuel assemblies and replace them.

Two fuel assemblies remained stuck to the upper internal holding structures during the removal operations. The operator interrupted these operations and proceeded to evacuate the reactor building and isolate it in conformity with the reactor’s operating rules. Both assemblies are under water in the vessel.

ASN and its technical support, the Institute for Radiation Protection and Nuclear Safety (IRSN), closely follow the development of the situation. ASN asked EDF to study the consequences of a possible fall of both assemblies into the vessel and to define the actions to take to remedy this incident.

The still unresolved incident did not have any consequences on the plant’s personnel and did not entail releases into the environment.

source: (Autorité de sûreté nucléaire)
EDF proposed to ASN to classify this incident a level 1 incident on the International Nuclear Event Scale (INES).

An incident of the same kind occurred at the nuclear power plant of Nogent-sur-Seine in 1999.


Incident describet above


Suez has agreed to acquire a 5% equity stake in Areva's new Georges Besse II (GB-II) uranium enrichment plant under construction at Tricastin, France.
Areva and Suez have signed an agreement under which Suez will acquire a 5% stake in Areva-owned Société d'Enrichissement du Tricastin (SET), which holds the GB-II plant, for an undisclosed sum.
In a statement the two companies said: "The agreement reflects the two group's intention to further develop their present industrial cooperation. With it, Suez will be able to secure a portion of its nuclear reactor supply needs in enriched uranium."
Suez owns Electrabel, Belgium's largest power generator which operates two nuclear power plants with a total of seven reactors (three at Tihange and four at Doel with a total capacity 5800 MWe). In early 2007, the company announced its intention of "increasing its nuclear power generation capacities through the construction of new power plants in Europe in line with national public policies. The objective for 2015-20 is to own and operate new third-generation nuclear plants."
Areva spokesman Julien Duperray told Bloomberg that the company is "open to the sale of further limited stakes in the plant."
The €3 billion ($4.7 billion) GB-II plant is based on "ultra centrifuge technology" and is scheduled to start operating in 2009. The plant will replace Areva's existing Georges Besse enrichment plant at Tricastin, which uses energy-intensive gas diffusion technology. In April 2007, the new plant received a licence to operate at up to 8.2 million SWU per year, enriching uranium up to a maximum of 6%.
Suez, through its Energy Services business unit, was selected by SET in July 2007 to participate in the construction of the GB-II plant. Three subsidiaries of Suez Energy Services - AXIMA, ENDEL and INEO - are building the electrical installations, and supplying the fluid management systems and process cooling equipment of the new plant.
In February, Areva announced that it had reached a "major milestone" by passing possession of the centrifuge assembly facility at the Tricastin site to Enrichment Technology Company (ETC), a joint venture between Areva and Urenco. ET France - a subsidiary of ETC - will start assembling centrifuges fabricated at its German and Dutch factories at Tricastin this summer.


Electricite de France (EDF) took Tricastin-1 down for 10 days last month especially to plug two steam generator tubes that maintenance crews had neglected to plug during the 900-MW PWR´s regular outage.


Three striking workers at the Tricastin 900MW PWR station penetrated a unit control room, trying to force their colleagues on duty at the time to lower plant load as part of the protest. EDF said in a statement that the strikers had "prevented the operators from piloting the facilities under the conditions of vigilance and attention required to guarantee nuclear safety." One of the Tricastin strikers was suspended for a month and his colleagues for three months; in addition, all three were transferred out of the nuclear sector.
Pierre Carlier, director of EDF said EDF owed it to customers to deliver power at all times, calling it "a product that has become...vital".
The sanctions were taken under a clause in a 1980 law on physical protection of nuclear materials, which allows sanctions including immediate suspension or breaking of a contract "without notice or compensation" for any employee who willfully violates safety rules in a facility containing nuclear materials.


Lack of safety culture: EdF PWRs are provided with "gray" CRs that absorb fewer neutrons than conventional "black" rods.To modify power level operators can either change boron concentration in coolant or change CR position. To allow fast shutdown, if needed enough CRs have to be left high enough in the core that they can stop chain reaction when they are dropped. But this "operation rule" was several times violated, by the operators attempts to follow the national grid load: 88 times since the latest startup. Shift opeartors failed to take rapid measures even if a control room alarm signalled the situation. Most of the violations were of short duration, but in some cases the rod position was not corrected for several hours.


At full power it was discovered that 2 of 7 safety valves of a SG were unavailable. the compressed air system was reversed, so that an order to open in fact blocked the valves closed. a similar situation , wich was traced back to 1988,was found on 1 other valve of another SG.


Unit was at full power when it was discovered that the protecion treshold setpoint for neutron flux imbalance had been calibrated erroneously.


During a tenth-year inspection it was found that the 3 globe lift check valves located on CCS piping upstream of MCPs were blocked open, because of corrosion. same corrosion problem was found at 11 PWRs: corrosion was found on 24 of 33 valves at nine 900 MW PWRs and on 4 of 8 valves at 2 1300 MW PWRs.


SI activated following a scram, because the pressure in 1 of the 3 SG dropped over 7 bar more than in the others. pressure imbalance was due to a thermosiphon caused by tripping of the MCP due to an electronic failure


Borated water supply system unavailable for 4.5 hours because of the erroneous closure of a valve, reactor should have been shut down after 1 hour,if the system cannot be put back in service.


Primary coolant level fell below 0.95 meter below the required level, during draining operations preceding closure of the RPV, due to poorly verified procedure


Unit was off-line when offsite power supply plus one of the two emerg. diesels were rendered unavailable. on 2 seperate occasions switch of a transformer interrupted the offsite power.


Fuel handling accident caused slight deformation of a fuel assembly.


Reactor protection signals from one of the 4 ionization chambers were discovered to be unavailable because of incorrect wiring in the associated data processing system. problem was not revealed during periodic testing, but during maintenance on the electrical cabinet.


Deterioration of a main coolant pump seal caused the pump to trip and the reactor to scram. about 300 cu. meters of primary coolant leaked onto the reactor building floor.


Tests of the containment vent filters revealed that the piping connecting the filter to the reactor building was blocked by a diaphragm. Similar defects were found at Tricastin-2, Chinon B3, Golfech-1, Penly-1, Cattenom-3.


RCS had been isolated at a pressure of 32 bar without having been stabilized beforehand, -> led to an excessive rise in coolant temperature, 25 °C over the limit. temperature limit was exceeded for about 3 hours during rise in pressure of the RCS


Unit was coming back from its annual outage when the rate of power rise reached 10% instead of 3%/hour. the rise to power had been disturbed by an external power demand which should not have affected the reactor.the incident was due to turbine backfits made during the outage that were designed to make the rise to power automatic


A defect in the contol rod clusters made operation of the reactor more difficult and led to violation of the operating limits