Cadarache Special - Plutonium Investigation n°20
 

Boxes

"Flaws in safety culture" and "Failure in operating procedures" at the ATPu

These stinging conclusions from the DSIN followed an incident which occurred in March 1992, classed at level two on the International Nuclear Event Scale (INES) 1. A spot inspection by the safety authority revealed the presence of an excessive number of "centering cages", devices making it possible to handle fissile materials and prevent the risk of criticality, in a storage area of the ATPu. "Criticality" means a situation in which a sufficient mass of fissile material is brought together in a configuration favorable to the triggering of an uncontrolled nuclear reaction. This serious anomaly in operation did not have any radiological consequences, but such "flaws in safety culture" and "failures in installation operating procedures" had "severe potential consequences" according to the DSIN, which suspended then the facility's activities. The improvements "proposed" by the operator covered operating procedures, monitoring, and raising of awareness among personnel; they led to the lifting of the DSIN's restriction one month after the accident. Nine years later, nothing had apparently changed as, on 18 April 2001, the Provence-Alpes-Côte d'Azur DRIRE — in a press conference on the status of safety at Cadarache in 2000 — recalled the "lack of rigor of the operators of the installations." 2

The more recent incident, on 17 December 1997, casts doubt on the measures adopted by the operator: "a mass of fissile material 50 per cent greater than that authorized by safety requirements" was placed in the centering cages. This failure to obey safety requirements may stem from a somewhat lax attitude on the part of operators and a lack of awareness of the "safety culture", but other factors directly incriminate the operating procedures themselves. Some operations, for which the degree of control varies, expose operators to potential risks. A look back over the history of operation of the ATPu and LPC highlights systematic loss of confinement causing contamination by plutonium of the premises and of personnel (reaching the Annual Limit of Intake (ALI) ). This was not the result of confinement failures but rather of contact with protruding metal objects in glove boxes, able to pierce the vinyl envelopes and operatives' gloves (even though these are lined). These recurring incidents led the safety authority to state, in its safety bulletin of January 1998, that "in spite of all precautions taken, such piercing of gloves could not be totally avoided." Two years later, a technician from LPC was contaminated again 3, with exposure at "around the Annual Limit of Incorporation." The incident was classed at level two on the INES, given the "significant contamination of areas accessible to personnel." It originated from the piercing of the double envelope of a package containing the residues of mixed uranium and plutonium oxide pellets and powdered plutonium oxide. On 25 April 1999, a level one incident at the ATPu involved piercing of an operator's protective glove by a metal shard.4 Such loss of confinement caused by piercing of vinyl envelopes has given rise to a number of incidents at the CFCa, two of which were classed at level two on the INES and in which the Annual Limit of Incorporation was reached for operators.

Another event confirms the flaws in the procedures at the ATPu. This time it was removal of materials that was pinpointed by the safety authority: 5 "failures in the procedures for removal of materials present in the installations" were revealed in a level one incident that occurred on 18 October 1991. Inspection of a truck "revealed that 40 Rapsodie type assemblies each containing 1.800 grams of depleted uranium were delivered in 1970 and never irradiated!"

Notes:

1 The International Nuclear Event Scale (INES) is used to indicate the gravity of any event occurring in nuclear power stations or other facilities. Level two corresponds to:
  • significant on-site consequences: significant contamination, overexposure of a worker,
  • degradation of defense in depth: incident with significant failure in safety provisions.

2 Provence-Alpes-Côtes d'Azur DRIRE, "Press Conference on Nuclear Safety at CEA Center at Cadarache in 2000", 18 April 2001.

3 See Contrôle review, January 1990.

4 See Contrôle review, June 1999.

5 See Contrôle review, December 1991.


MOX Plants in the World: capacities and output at end of 2000

Site
Country
Operator
Capacity
in tHM
Type of
fuel
Commissioning
Output
in 2000
in tHM
Total at
end 2000
in tHM
Clients
CFCa
(Cadarache)
France
CEA - COGEMA
1.5
FBR
1961
0.0
~ 105.0
FR, DE
and 35
PWR/BWR
1989
41.4
244.9
MELOX 1
(Marcoule)
France
COGEMA
101.3
PWR
1996
101.0
434.6
FR, JP
and 44.2
BWR
1999
MDF
(Sellafield)
United Kingdom
BNFL
8
PWR/BWR
1993
0.0
2 ~ 18
DE, CH, JP
P0
(Dessel)
Belgium
Belgonucleaire
10
FBR
1973
0.0
 
FR, B, DE, CH, JP
or 35
PWR/BWR
1986
37.0
451.9
PFPF 3
(Tokai Mura)
Japan
JNC
40
ATR
1988
0.0
0.0
JP
or 5
FBR
0.0
~ 16
PFFF 3
(Tokai Mura)
Japan
JNC
10
ATR
1971
~ 6.0
~ 150
or 1
FBR
0.0
0.0
AFFF
(Tarapur)
India
BARC
20
PHWR
BWR ?
1990 ?
?
?
India

PFPF : Plutonium Fuel Production Facility
PFFF : Plutonium Fuel Fabrication Facility
AFFF : Advanced Fuel Fabrication Facility
BARC : Bhabha Atomic Research Center

Notes:

1 The technical capacity of MELOX is more like 145.5 tHM but its output is limited by decree (n°99-664 du 30/07/1999), to 101.3 tHM

2 BNFL, written response to Sellafield Local Liaison Committee, dated 2 December 1999. from CORE (Cumbrians Opposed to a Radioactive Environment)

3 According to CNIC (Citizens’ Nuclear Information Center), Tokyo

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