ASN Report 2015

This anomaly is linked to thepresence

of ahighcarbonconcentrationwhich

results in mechanical properties that

arenot as goodas expected. ArevaNP

sentASNafilepresentingtheapproach

it plans to implement to demonstrate

the sufficiency of the mechanical

properties of the material used in

themanufacture of the vessel closure

head and bottom head for the future

FlamanvilleEPRreactor.Thisapproach

willinparticularbebasedonthefuture

results of aprogrammeofmechanical

and chemical tests.

On12thDecember 2015, ASNissued

a position statement concerning

the approach used to demonstrate

the mechanical properties of the

Flamanville3EPRvessel closurehead

andbottomheadproposedbyArevaNP.

Subjecttoitsobservationsandrequests

being taken into consideration, ASN

considers that the approachproposed

byArevaisacceptableinprincipleand

hasnoobjection to the initiationof the

planned programme of tests.

ASN assessments

Nuclear Power Plants (NPPs)

ASN considers that management of

reactor operation is on the whole

satisfactory. It however considers

that the involvement by the corporate

headofficedepartments inmonitoring

the application of the prescription

documents by the NPPs needs to be

improved. Management of external

operating experience feedback is still

not robust enough, bothbetween the

sites and with regard to EDF head

office departments.

In2015, EDFnotified586 significant

safetyevents,109concerningradiation

protection and 79 concerning

protection of the environment. The

number of safety incidents notified

was slightly down compared to 2014

(-8%).

ASN considers that EDF’s internal

independent safety system fulfils its

role of verificationof themeasures and

decisions takenby thedepartments in

charge of operating the installations.

Greater traceability is however

requiredoftheelementssubstantiating

this verification process on the one

hand and the stances adopted on the

other.

With regard to theperiodic equipment

tests, even though improvements

by comparison with 2014 had

been observed on the sites, efforts

must be maintained with regard

to management of the planning,

preparation and performance of

these tests. The process implemented

for subsequent confirmation of the

validity of the testsmust be reinforced

in order to promote a questioning

attitude.

Concerning the performance of

maintenance work, ASN observes

that the number of quality defects

found is on the whole stable. It

observes that the maintenance

workers still face constraints linked

to the organisation of the work, the

inadequate preparation of certain

activities or the working conditions.

EDFhas implementeda specificmulti-

year actionplandesigned to reinforce

themanagementofactivitiesscheduled

and carried out duringmaintenance

outages of nuclear power generating

reactors. Even if this action plan has

led tomore serenemanagement of the

preparation andperformance phases

by the licensee, ASN considers that

EDF must continue with its efforts

over the long term, inparticular in the

light of theEDF industrial programme

for the coming years.

ASN considers that EDF must

continue its efforts concerning

the identification and traceability

of the deviations detected. The

potential severity of certain generic

conformity anomalies demonstrates

that EDF needs to manage the

operational processes contributing

to maintaining the conformity of

the installations with their design,

construction and operating baseline

requirements.

ASN considers that in 2015, the

condition of the first containment

barrier, consistingof the fuel cladding,

is on the whole progressing, despite

a few points to be improved. 2015

was marked by the shutdown of the

Nogent 2 reactor before the normal

end of its operating cycle following a

significant increase inabsorber cluster

drop time. This increasewas the result

of the deformationof fuel assemblies,

which were repaired.

ASNconsidersthattheconditionofthe

steamgeneratorswas improvedby the

replacement of the last steamgenerator

equippedwith tube bundlesmade of

600MA alloywhichwas susceptible

tocorrosion. ASNconsiders that EDF’s

operating and maintenance strategy

concerning steamgenerator clogging

is appropriate.

ASNconsidersthattheorganisationset

up by the plants tomonitor activities

and systems liable to have an impact

on static and dynamic containment

in the installations is on the whole

satisfactory. The results of the ten-

yearlyinspectionsonthecontainments

were satisfactory, with the exception

of Bugey reactor 5, which needs to

be repaired. ASN is also remaining

vigilant concerning the evolution

of the tightness of the double-wall

containments, for which EDF has

made prevention and surveillance

commitments.

The inspections carried out in 2015

onemergencymanagementconfirmed

the satisfactory organisation of the

plants in this area. The crews who

will implement the on-site emergency

plans are adequately sized and all

emergency crewmembers takepart in

an annual exercise. The preparedness

for emergency situationmanagement

canhoweverbeimproved,inparticular

concerning the management and

utilisation of mobile equipment

employed in an emergency situation

and through lessons learned fromthe

emergency exercises.

ASNnotes that the relations between

the sites and the departmental fire-

fighting and emergency services

are on the whole satisfactory and

that the response organisation is

generally not found to be wanting

in the management of actual fires.

Nonetheless, the observationsmade

in previous years with regard to

sectorisation, detection,management

of calorific potential and fire permits,

are still valid. Thenumber of outbreaks

of fire recorded for 2015 is higher

than that for 2014.

ASN Report on the state of nuclear safety and radiation protection in France in 2015

SIGNIFICANT EVENTS IN 2015