Supervision and Safety of Complex Systems

Chapter 10Detection/Classification of Argon and WaterInjections into Sodium into an SG of a FastNeutron Reactor ¹

 

 

 

10.1. Context and aims

In the context of the research meant to develop a fourth-generation nuclear power plant, the use of liquid sodium as coolant is investigated. This solution would necessitate the development of specific monitoring tools. The reaction between (pressurized) water and sodium, a potential identified risk in steam generators (SGs), is a major issue in such a case.

To increase our knowledge about the acoustic response created by the reaction between sodium and water, we have studied signals measured during a specific experiment done at the shutdown of a PFR fast neutron reactor nuclear station in the UK in 1994. To simulate this chemical reaction, the AEA carried out tests using injections of argon and water into the liquid sodium in one of the SGs. This experiment aimed at testing the ability of the acoustic monitoring devices to detect a reaction between sodium and water (in case of a leak in one SG's tubes).

The study of these data, provided by the CEA [ORI 96, ORI 97a, ORI 97b], has a dual aim. On the one hand, it sought to assess the sensitivity of the acoustic monitoring system in the case of water-sodium reaction. On the other hand, it tried to compare the detectors' response to injections of water with those obtained using argon to determine the possibility, for monitoring system periodic controls, to simulate sodium-water reactions (consequences ...