ASN Report 2015

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3.4.3 Notable findings relating to radiation
protection of personnel
Advisory Committee meeting
TheAdvisoryCommitteeforNuclearReactors(GPR)metat
the request of ASN in order to rule on the strategy adopted
by EDF to limit collective and individual doses of ionising
radiation received by workers in its NPPs in operation in
France,morespecificallyfortheprojecttorenovatetheNPP
fleet over the period 2015-2025.
Significant contamination events
Three significant contamination events were notified in
2015 in the NPPs operated by EDF. They concern:
• contamination of the face of a contractor staff member
assigned towork on an exchanger on the chemical and
volume control system on the primary system of the
Le Blayais NPP, leading to exposure in excess of the
regulation limit per square centimetre of skin. This
event was rated level 2 on the INES scale;
• contamination of the face of a contractor staffmember in
charge of checking the tag-out padlocks on the valves of
the spent fuel pit cooling system in the Gravelines NPP,
leading to exposure in excess of one quarter of the
regulation limit per square centimetre of skin. This
event was rated level 1 on the INES scale;
• contamination of the face of a contractor staff member
through contact with a contaminated rope during
handling of heat insulation plates in the Nogent NPP,
leading to exposure in excess of one quarter of the
regulation limit per square centimetre of skin. This
event was rated level 1 on the INES scale.
3.4.4 Notable findings relating to the environmental
impacts of NPPs and discharges
Revision of the prescriptions concerning water
intake and effluent discharges
In 2015, ASN completed its examination of the water
intake and effluent discharge files for theChinon andSaint-
Laurent-des-Eaux NPPs and continued its examination
of those for Fessenheim, Cruas and Paluel.
TheASNresolutions issued accordingly (see point 2.14.1)
dealwith themodificationsmadebyEDF to the installations,
such as changes to the chemical conditioning of the
secondary system and the adoption of anti-scaling or
biocidal treatment of the cooling systems (see point 1.4).
They also take account of changes to the regulations.
ASNalso continued its reviewof the EDF files concerning
implementation on the NPPs of water intake systems
designed toguarantee “ultimatemakeup”water in the event
of anaccident, as prescribedby the “post-Fukushima” stress
tests (see point 3.1). ASN more specifically temporarily
authorised the Chinon and Dampierre-en-Burly NPPs
to carry out groundwater pumping tests to determine
whether this could be used as the ultimate cooling water
make-up source.
Finally, ASN authorised the transfer of non-radioactive
warmwater from the Gravelines NPP cooling systems to
the methane tanker terminal in Dunkerque.
Compliance with discharge limits
InCattenomNPP, the annual authorised release of copper
was found to have been exceeded in 2014. ASN thus
served formal notice on EDF in January 2015 to take all
steps to ensure compliance with this limit value in 2015.
ASN then checked the technical and organisational steps
taken, inparticular formonitoring of discharges, to ensure
compliance with this formal notice.
Level 2 incident in Le Blayais NPP:
irradiation of a worker during a scheduled
outage of reactor 4
On 21st August ASN was informed by EDF of the exposure
of a worker from an EDF contractor to a dose of ionising
radiation in excess of the regulation limit.
On 18th August, during the check carried out prior to exiting
the controlled area, contamination was detected on the chin
of the staff member. He had been assigned to maintenance
work in preparation for the hydrotesting of an exchanger
on the chemical and volume control system in the reactor 4
safeguard auxiliaries building in the Le Blayais NPP.
The worker was then cared for by the site’s risk prevention
service, which carried out decontamination operations. During
these operations, the radioactive particle which caused the
contamination was found and immediately removed. The
occupational physician then assessed the whole body dose
received and the dose on the skin of the chin.
For workers liable to be exposed to ionising radiation during
their professional activities, the annual regulation dose limits
are, for twelve consecutive months, 20 mSv for the whole
body and 500 mSv for a skin surface area of 1 cm2.
The evaluation made by EDF of the dose received by the
worker’s chin is higher than the regulation limit for the skin.
The whole body dose received by the worker is well below
the annual regulation limit.
ASN carried out an inspection on the site on 24th August
2015. The inspectors checked that EDF and the contractor
had taken all necessary steps for adequate management
of the incident and analysis of its causes.
Owing to the regulation annual dose limit for the skin being
exceeded, EDF proposed rating this event level 2 on the
eight-level (0-7) INES scale. ASN confirmed the level 2 rating
of this incident.
TO BE NOTED
398 CHAPTER 12: EDF NUCLEAR POWER PLANTS (NPPs)
ASN report on the state of nuclear safety and radiation protection in France in 2015