Areva - Reference Document 2016

RISK FACTORS

4.4 Industrial and environmental risks

risks associated with the use of pressurized equipment;

risks associated with utilities (electricity, water, steam, industrial gases, etc.).

These risks are managed using an approach similar to that used for nuclear risk

management, depending on the nature of the risk and in compliance with regulatory

requirements defined for each technical field: safety systems, fire containment,

detection, Atex rules for explosive atmospheres, separation of incompatible

chemicals, etc. These technical measures are supplemented as necessary by

compliance inspections, periodic verifications and maintenance, and operator

training and/or certification.

Measures are also adopted to minimize the consequences of a failure when an

incident may have an impact on nuclear safety. Automatic fire detection systems are

used for early alerts to employees trained to respond to and extinguish a fire start.

Response means are also provided (e.g. fire department in the event of a fire start).

The use of uranium hexafluoride (UF

) is a risk highly specific

to the group’s operations

Enrichment operations involve the handling of uranium in the chemical form of

uranium hexafluoride (UF

), which is solid at normal temperatures and pressures

and becomes gaseous when heated (sublimation at about 56°c). This gas can react

when it comes into contact with water vapor in the air, forming uranium oxide and

hydrofluoric acid, a compound which is highly toxic to humans, plants and animals.

In view of the large quantities of UF

handled at the production sites, the inherent

risks were factored into the design of the facilities (double containment barrier,

automated monitoring of high-risk areas, etc.).

Other risks, such as those related to parallel activities and to human and

organizational factors, are also taken into account. Prior coordination of activities

by the parties involved and the establishment of a suitable organization combined

with personnel training in particular help limit these risks.

4.4.1.3.

EXTERNAL RISKS THAT COULD LEAD

TO NUCLEAR RISK

Unlike risks of internal origin, it is not always possible to act on risks of external origin

related to the facility’s environment. However, their originmust be taken into account

to reduce and manage their consequences, particularly in terms of radiation. The

desired level of protection is ensured by considering in particular unforeseen but

highly improbable events in the context of each site.

Earthquake

Earthquakes and their possible repercussions, such as a tsunami, can cause

damage that could disable nuclear safety systems.

For facilities in which nuclear materials are handled, the risk of an earthquake is

factored into the design of equipment, systems and buildings. Risk analysis consists

of demonstrating that no damage affecting the nuclear safety of the facility is likely

to occur for the event scenario considered.

Airplane crash

This risk concerns the crash of an airplane or part of an airplane on a facility. Its

probability of occurrence depends on the number of aircraft that could reach the

site without being detected; its potential severity depends on the type of aircraft and

the surface area of sensitive areas in each facility. Each site is located:

away from controlled airspace;

away from airspace used by military aircraft; and

far from any airport.

Safety studies are carried out to assess the risk of an airplane crash, including the

risk of deliberate attack, and to determine the means for limiting its consequences

(factoring in the organization of airspace use, types of flights, known crash

statistics, etc.).

Special measures are taken to protect nuclear facilities from terrorism. These

measures have been strengthened under the French national security plan known

as “Vigipirate”. For security reasons, these measures may not be disclosed to the

public.

Adverse meteorological conditions and flooding

This risk is factored into the design based on potential local weather conditions.

Advance warning is given for any threatening weather conditions, and there are

instructions for each facility concerning additional measures to be taken, such as

increased monitoring or specific actions.

The possible causes of external flooding (rain, river flooding, breach of levies,

tsunami) are factored into the design of the facilities and operating measures. The

risk of a thousand-year flood is taken into account, in particular by locating facilities

above the thousand-year flood plain.

Other risks caused by potential external events, such as the loss of power supply

or utilities (water, steam, compressed air, etc.), are addressed through redundant

or independent backup systems.

Following the accident at the Fukushima Daiichi nuclear power plant in Japan,

in addition to measures taken in the design of the facilities or during operations,

supplementary safety assessments (SSA) were carried out to evaluate the facilities’

ability to withstand a malfunction. Based on these assessments, special programs

to improve the level of facility protection led to work and actions (see Appendix 3,

Section 2.

Environmental information

of the 2015 Reference Document). Other

measures are being implemented in accordance with regulatory decisions by ASN

applicable to the group’s nuclear facilities.

4.4.1.4.

TRANSPORTATION OF RADIOACTIVE MATERIALS

To protect members of the public, property and the environment from the effects

of radiation during the transportation of radioactive materials on public lands, the

“defense in depth” concept applies to these operations, as it does to other nuclear

operations. This concept consists of setting up a series of barriers – safety systems,

procedures, technical or administrative controls, etc. – to prevent accidents and limit

their consequences. The design of the shipping cask is the main component of

this system. As with any nuclear activity, these operations are governed by stringent

international regulations.

If the materials transported exceed a certain level of activity set by regulation, the

cask must, under normal and accidental operating conditions, provide:

materials containment;

constant sub-critical conditions when fissile materials are transported;

control of radiation intensity; and

protection from the heat of the materials transported to prevent damage.

2016 AREVA

REFERENCE DOCUMENT