ASN reports on its examination of the technical documentation on the instrumentation and control system of the Flamanville 3 EPR

In order to improve the robustness of the instrumentation and control (I&C) system [1] of the EPR reactor, ASN asked EDF to modify one of the reactor’s control platforms. EDF had already considered this modification towards the end of 2009 in response to ASN’s request on 15 October 2009.

On 15 October 2009 ASN had in fact pointed out to EDF that the safety of an item of equipment in the I&C system of the Flamanville 3 EPR reactor (SPPA T2000 platform) was not demonstrated and had particularly asked EDF to provide additional information and to examine different design options.

Since then EDF has worked hard to comply with ASN’s requests. Its initial response and additional information were sent to ASN at the end of 2009 and subsequently.

The I&C system (see diagram) of the Flamanville 3 EPR comprises two associated platforms:

• the Téléperm XS platform, specifically developed for the nuclear industry and designed to protect the reactor during incidents or accidents;
• the SPPA T2000 platform, of “conventional industrial” origin, used for functions associated with normal reactor operation and for some functions designed to protect the reactor during incidents or accidents.

Once ASN and its technical support agency IRSN had examined the initial information provided by EDF, ASN concluded in a letter to EDF dated 9 July 2010 that the ability of the SPPA T2000 platform to accommodate certain reactor protection functions still had to be demonstrated. ASN therefore asked EDF to modify the SPPA T2000 platform in order to improve its robustness and enable it to be used for EPR-type reactors. This modification involves duplicating on the Téléperm XS platform some reactor protection functions accommodated by the SPPA T2000 platform.

To enable ASN to complete its examination of the documentation on the I&C system, EDF must submit detailed information about this design improvement and its impact on demonstrating reactor safety to ASN before the end of 2010.

[1] The term “instrumentation and control” includes the following elements:

• sensors (temperature, pressure, etc.);

• devices that, on the basis of a certain amount of input data, devise automatic orders to maintain parameters within authorised limits, or to trigger protective measures such as a reactor trip;

• system/control room operator interfaces (control panels, alarms, etc.).

Since these elements fulfil an important role in reactor safety, they are subject to very strict requirements.