Unlike large nuclear power plants that typically have one control room for each unit, compact plant designs like SMRs are more likely to operate multiple modules from a single central control room. Plants that employ multi-module control rooms will inherit a number of characteristics from NPP control rooms as we know them today. As in the past, the primary purpose of the control room and the HSIs within it will still be to enable the operator to control the plant safely and effectively. They are also used to monitor and direct complex operational activities, such as optimising the combined output of the modules or units.

The most likely characteristics of multi-module control rooms would include the following:

• The need for a high level of automation, integration and synchronisation of systems, and optimisation of output. This suggests a single control room from where a minimum crew can manage the entire plant, while still being able to control and monitor the operation of individual modules and systems.

• The use of advanced HSIs to simplify the display of complex system functioning and to minimise the safety-critical, potentially high consequence nature of the control task.

• The change in the central role of the control room operator to system supervisor.

• The existence of new regulatory measures to govern the control room procedures and interface technologies.

7.7.12 LCSs

NUREG-0700 (2007) defines an LCS as ‘A place outside of the main control room where operators interact with the plant. LCSs may include multifunction workstations and panels, as well as operator interfaces, such as controls (e. g. valves, switches, and breakers) and displays (e. g. meters and VDUs)’. NUREG/CR-6146 (Brown et al., 1994) identifies multifunction and single-function LCSs:

• A multifunction LCS is any operator interface used for process control not located inside the control room and not consisting solely of manually operated valves or circuit breakers.

• A single-function LCS is defined as any operator interface, excluding multifunction control panels, that is not located in the control room. This type includes all controls (valves, switches, breakers) and displays (meters, gauges, monitors) operated or consulted during normal, abnormal, or emergency operations.

We can expect that many manual actions that were common with LCSs will be replaced by automated control to eliminate many of the discrete controls mentioned above. Instead, operators will be able to use digital controls and more advanced displays to control and monitor local processes (Brown et al., 1994).