417 / 536
Furthermore, the management of the Tricastin site
submitted an authorisation application to ASN on
13th July 2012 for implementation of an internal
authorisation process, comparable to that already in place
on Areva’s La Hague site. After a two-year review process,
ASN approved this system in resolution 2014-DC-0460
of 23rd September 2014. This relieves the licensees of
BNIs 93, 105, 138, 155 and 168 of the need to submit
prior notification of modifications and operations
considered to be “minor”, as they comply with the
criteria set by the above-mentioned ASN resolution.
This resolution requires that the licensees inform ASN
of the anticipated programme of operations concerned,
at least once a year, and send it an annual summary
of the system. This resolution entered into force on
1st January 2015.
Areva NC TU5 facility and W plant - BNI 155
On the Tricastin site, Areva NC operates:
•
the TU5 facility (BNI 155) for conversion of uranyl
nitrate UO
2
(NO
3
) 2 produced by reprocessing spent
fuel into uranium sesquioxide U
3
O
8
;
•
the W plant (ICPE within the BNI perimeter) for
conversion of depleted uranium hexafluoride (UF
6
)
into uranium sesquioxide (U
3
O
8
).
U
3
O
8
is a stable solid compound able to guarantee safer
uranium storage conditions than in liquid or gaseous
form. BNI 155, called TU5, can handle up to 2,000 tonnes
of uraniumper year, enabling it to reprocess all the uranyl
nitrate produced by the Areva plant at La Hague. Once
converted, the uranium from reprocessing is placed in
storage on the Areva NC Tricastin site.
The review report was transmitted on 28th November
2014. This file is currently being reviewed by ASN.
The conclusions of this review will be released at the
end of 2016.
ASN considers that the facilities located within the
perimeter of Areva NC’s BNI 155 are operated with a
satisfactory level of safety.
The new hydrofluoric acid storage area entered service
satisfactorily at the beginning of 2015. This work is
improving risk prevention during the transfer operations
involving this product. The technical prescriptions for
operation of the facility were also updated.
The licensee is also required to create a new emission
area in which the depleted UF
6
is heated so that it can
be emitted in the process used in the W plant (EM3),
the commissioning of which is planned for 2018, as
part of the safety improvements specified by ASN. This
new area must ensure a higher level of protection thanks
to the creation of a concrete building (in place of the
existing building made of cladding), in order to improve
seismic resistance, prevent the fire risk, the explosion
risk, the dispersion risk and improve the containment
and purification of gaseous effluents. Examination
of the file began in 2015, as did preparations for the
construction site.
Comhurex uranium hexafluoride
preparation plant - BNI 105
On 1st January 2014, Areva NC took charge of operating
the BNI 105 on the Tricastin platform, in place of the
former licensee, Comurhex.
The ICPEs not needed for operation of the BNI are included
in the perimeter of BNI 105 operated by Areva NC owing
to the related risks, that is the risks created by these
ICPEs to the safety of the BNI, which is also undergoing
decommissioning (see chapter 15). These ICPEs are
primarily devoted to the fluorination of uranium, in
the form of uranium tetrafluoride (UF
4
) into uranium
hexafluoride (UF
6
) so that it can be subsequently enriched.
Each year, they produce about 14,000 tonnes of UF
6
from
the UF
4
coming from the Areva NC Comurhex facility
in Malvési. Until 2015, they also produced chlorine
trifluoride (ClF
3
) used for rinsing the diffusion cascade
in the Georges Besse plant as part of the operations to
prepare for decommissioning. This production is today
stopped, which eliminates all the risks linked to this
activity. This ICPE is one that requires authorisation and
comprises institutional controls (Seveso) and is subject
to the financial guarantees arrangement for making the
facilities safe and, finally, is subject to the industrial
emissions directive.
The plant’s production tool will bemodernised through the
construction and then commissioning of the Comurhex II
installations, initially scheduled for 2015 and currently
planned for 2018, while the existing plant, Comurhex I,
will close by the end of 2017. Unit 61 in Comurhex I
was commissioned in October 2013 but delays in the
new plant project led Areva NC to ask ASN to authorise
continued operation of the old ICPEplants. This operating
extension of the Comurhex I plants from July 2015 up
to the end of 2017 was accepted in 2015.
This extension was covered by ASN resolution
CODEP-LYO-2015-024792 of 30th June 2015 which
prescribed themain reinforcement work required on these
plants. Thiswork inparticular concerns the implementation
of mitigationmeans to limit the consequences of amajor
hazardous gas leak in the process buildings, the anticipated
shutdown of the installations (storage of propane and
ammonia, recycling of the hydrofluoric acid), connection
of the gauges room to the gas pressure reduction control
system and improvement of the safety system to make
it independent of the control system. On 11th August
2015, ASN carried out a dedicated inspection on the
actual implementation of these main improvements.
Areva NC also continued its work to improve the
containment of the 400 structure. Anumber of significant
loss of containment events in this structure nonetheless
occurred in 2015. ASN is thus remaining particularly
vigilant to ensuring that sufficient stringency ismaintained
417
CHAPTER 13:
NUCLEAR FUEL CYCLE INSTALLATIONS
ASN report on the state of nuclear safety and radiation protection in France in 2015