The control panel is referred to as the “control board” or “vertical board” in the electric utility industry A variety of control instruments, recorders, indicators, meters, dials, and knobs are installed on the control panels The more familiar instrument systems include (1) switchgear and substation control, (2) turbine and generator control,

(3) critical-temperature measuring recorders and scanners,

(4) process instruments for controlling and monitoring critical pumps and valves in the auxiliary heat transfer loops, (5) emergency shutdown and monitoring for water reactors, (6) water treatment, and (7) annunciator alarm windows for all control panels involved The neutron­monitoring instrumentation cabinets and drawers and the radiation-monitoring system may be installed as part of the control panel or in separate cabinets

The depth of a control panel should be no more than required for easy access to all terminals and components at the rear Avoid stacking instruments and conduit boxes behind panel board instruments at the rear of the control panels It limits access to terminals and components at the rear of the panels and can adversely affect the safety of plant operation

Field cables entering the control panels either from floor conduits or from overhead trays should be bundled

“ Ml И. P » }} щ Щ i,
Fig. 10.1—Control room of the San Onofre nuclear generating station.
MATRIX PARTIAL TRIP ANNUNCIATOR
FIRST-OUT AND PRE­TRIP ANNUNCIATOR	REACTOR PLANT ANNUNCIATOR N0.1
PERMISSIVE DISPLAY
AUXILIARY COOLING WATER CONTROLS
PROCESS CONTROLS PROCESS RECORDERS
■ STEAM-GENERATOR CONTROLS READOUT RECORDS FEEDWATER CONTROLS MAKE-UP WATER CONTROLS
MAIN CONTROL, CONSOLE
-PRIMARY LOOP CONTROLS READOUT RECORD	-NUCLEAR INST. READOUT CONTROL-ROD CONTROLS READOUT RECORDER
OPERATOR’S LOG DESK AND STATION COMMUNICATION CENTER
-TURBINE-GENERATOR CONTROLS READOUT RECORD
u- <

and installed in a manner that will not inhibit access to any instruments, components, controls, or termination points at the rear of the control pane! The installation of racks and cabinets is discussed in Sec 10-3

Graphic panel installations already generally accepted for control in fossil-fueled power plants are being used in nuclear power plants, particularly for generator output bus, switch gear, substations, and heat-transfer systems Opin ions differ as to the effectiveness of graphic panels since the plant operator gets accustomed to the control knobs, lights, indicators, etc (see Sec 10-6) However, a survey of operating personnel in several generating plants revealed a decisive preference for graphic panels m the central control room

9- 2.4 Nuclear-Instrument Systems

Slide out drawers containing electronic circuits which are housed in some modular arrangement have been accepted as a standard for nuclear industry Either a Nuclear Instrument Module System (NIMS) bin configura­tion is used or modules are removed from the top of the chassis The installation and interfacing of nuclear mstru ments with the control and signal cabling coming into the cabinet must be done properh

Very serious operating problems will affect the perfor­mance of the nuclear instrument channels if there is improper installation and bundling of critical coaxial, triaxial, and multiconductor cables Cables that are improp­erly installed frequent!) break otf after they have been flexed a few times, causing open circuits Adherence to the following practices will reduce this problem

1 Avoid supporting a cable, wire, or bundle of wires by the terminal point Good engineering practice provides a solid support fastened to the cable, wire, or bundle such that there is no stress on the terminal Support as much of the cable length as possible bv such mechanical means as cable retractors and springs

2 Avoid using a single-point support Distribute the support points over as wide an area as possible

3 Mount the cable, wire, or bundle so that kinks do not develop Use mechanical stiffening, such as nlon spiral wrap, wherever possible to prevent sharp bends

10- 2.5 Plant-Protection-System Cabinets

Cabinets for the plant protection system contain relays, solid state devices, and other components that make up the logic circuits of the plant protection system The plant protection system should be totally enclosed, either the cabinets themselves or the area in which open cabinets are located

The equipment should be designed so that anv compo­nent can be replaced or repaired without disturbing anv other component Relays and other remotely operated equipment should be accessible for authorized maintenance and troubleshooting and protected against unauthorized access Each component should be clearly marked to prevent a mistake m identification

The cabinet terminal blocks, used to interface the field wiring to the cabinet wiring, should be accessible to the incoming cables as well as to the internal wiring The wiring on the terminal block should be arranged so that the internal wiring is terminated on one side of the terminal block and the field wiring on the other side

Terminal blocks that do not contain field wires may utilize both sides of the terminal block for internal wiring, particularly where it is convenient to install a series of shorting bars In installations where more than one row of terminal blocks is used, the internal wiring should be terminated on the terminals facing a common space between the terminal blocks, thereby leaving a space common to two rows of terminal blocks for the incoming cable terminations

All terminal blocks installed in the plant-protection — system cabinets should be clearly identified by both block and terminal point