ASN Report 2015

EDF Nuclear Power Plants (NPPs)

ASN imposes stringent safety

requirements on power reactors, the

regulation and oversight of which

mobilises nearly 200 of its staff and

asmany IRSNexperts onadailybasis.

ASN is developing an integrated

approach to regulation that coversnot

only the design of new installations,

their construction, modifications,

integration of feedback on events or

maintenanceproblems,butalsohuman

and organisational factors, radiation

protection,environmentalprotection,

worker securityand the applicationof

labour legislation.

Significant events

Experience feedback from

the Fukushima Daiichi accident

In the wake of the Fukushima

Daiichi accident, ASN issued a

set of resolutions requiring the

operators of major nuclear facilities

to perform stress tests. Further to

these stress tests, ASN issued a range

of resolutions in 2012, requiring

EDF to take additional steps to

reinforce the robustness of the

NPPs to extreme situations, more

specifically:

•

a «hardened safety core» able to

perform vital safety functions in

the event of hazards or unforeseen

circumstances exceeding those

adopted for the general design of

the facility;

•

aNuclear Rapid InterventionForce

(FARN)which, usingmobilemeans

external to the site, can intervene

on a nuclear site in a pre-accident

or accident situation;

•

a range of corrective measures

or improvements, notably

the acquisition of additional

communication and radiological

protectionmeans, the deployment

of additional instrumentation.

EDF first of all deployed temporary

or mobile measures to enhance

protection against the main

situations of total loss of the heat

sink or electrical power supplies.

EDF initiated studies designed to

deploy robust means on all the sites

to protect against extreme hazards in

order to deal with these situations.

NPP operating life extension

EDFmust carry out a periodic safety

reviewof its reactors every ten years.

This reviewconsists, on the onehand,

of a detailed check on designs and

equipment and, on the other, of a

reassessment of safety by comparison

with the most recent facilities and

international best practices. On

this occasion, EDF corrects the

deviations detected and identifies

the modifications it intends tomake

to reinforce the safety of its reactors.

On a case by case basis, ASN then

decides on the continued operation

of each reactor, if necessary issuing

additional prescriptions.

In 2015, ASN examined EDF’s

proposals for the continued

operation of the 900 MWe nuclear

reactors beyond their fourth ten-

yearly in-service inspection. This

is of particular importance as it

runs contrary to the initial design

hypotheses for a certain number

of equipment items. The studies of

the conformity of the installations

and the management of equipment

ageing must thus be reviewed,

taking account of the deterioration

mechanisms actually observed and

the maintenance and replacement

strategiesimplementedbythelicensee.

In March 2015, ASN ruled on the

generic aspects of the continued

operation of the 1,300MWe reactors

beyond thirty years. ASN considers

that the measures planned by EDF

to assess the condition of these

reactors and manage their ageing

are acceptable. ASN also considers

that the modifications identified by

EDF following this study phase will

make a significant improvement to

the safety of these installations.

In February 2015, ASN ruled on the

orientations of the periodic safety

reviewassociatedwith the second ten-

yearly in-service inspections of the

1,450MWe reactors. ASNinparticular

considers that the safety objectives to

be adopted for this review must be

defined in the light of the objectives

applicable to new reactors.

Flamanville 3 EPR

On 19thMarch 2015, ASN received

the commissioning authorisation

application for Flamanville 3. ASN

consideredthatadditionalinformation

was needed before it could rule on

this application,more specifically the

conformity of the as-built installation

with the file submitted, the design of

the systems or the accident studies.

Flamanville 3 EPR reactor vessel

anomaly

In late 2014, Areva NP informed

ASN that tests performed on a vessel

head representative of that intended

for the Flamanville EPR showed the

presenceof anareawithahighcarbon

concentration leading to lower than

expected mechanical properties.

Measurementsconfirmedthepresence

of this anomaly in the closure head

andbottomheadof theFlamanville3

EPR vessel.

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

SIGNIFICANT EVENTS IN 2015