3.4 - Operational aspects of experimental liquid metal facilities

Graham Kennedy, Ivan Di Piazza, Serena Bassini

Research outputpeer-review


Generally, the operation of liquid-metal facilities and the associated components
should not be vastly different from conventional systems operation. However, as
introduced in the beginning of this chapter, the relatively high temperatures and properties of liquid metals present some unique operational and safety aspects. This section therefore intends to inform new and current users of liquid-metal facilities about some typical but unique aspects of liquid-metal facility operation, previously experienced on existing facilities. Following good operational practices is important for the safety of personnel; protection of experimental infrastructure investments; and producing high-quality, representative, and repeatable experimental data.
While not necessarily specific to liquid-metal facilities, it is customary in many
system engineering processes to develop a functional performance specification
(FPS). Such a functional specification is not intended to describe the details of the
system implementation, but rather describes how the system should function during normal operation and during off-design scenarios. The FPS also defines the proposed interaction between the user and the software system and in turn defines or forms part of the operational procedures.
Defining so-called system states and modes is a commonly used method to describe the functionality of a system. Fig. 3.4.1 illustrates a very simplified mode and state flowchart that could be applied to a liquid-metal facility. With reference to the example state flow diagram in Fig. 3.4.1, the typical generic states are identified and tabulated in Table 3.4.1.
Using a state and mode approach, as shown in Fig. 3.4.1, allows the functional
requirements to be uniquely defined for each state. For these states to exist independently, there must also be transitions (sequences) between these states. For example, filling, draining, purging (gas conditioning), coolant circulation start-up and shutdown, emergency shutdown (e.g., in case of a leak), heating, and cooling are typical transition sequences that could be applicable in experimental liquid-metal facilities. This system approach also allows the system owners or designers to define the requirements for a transition sequence to be triggered, that is, transition set-point triggers and interlocks. Depending on the system complexity and the choice of hardware/software (e.g., manual valves as opposed to actuated valves), these triggers can be manual or automated or a combination of both. Manual triggers will require user input in the programmable logic controller (PLC). Automated triggers will be initiated by feedback from instrumentation with appropriate set points.
Original languageEnglish
Title of host publicationThermal Hydraulics Aspects of Liquid Metal Cooled Nuclear Reactors
PublisherWP - Woodhead Publishing
Number of pages19
ISBN (Print)978-0-08-101980-1
StatePublished - 5 Dec 2018

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