R. James Hall, Jerry J Engel, Gordon W. Young, and R. W. Madsen

10- 1 INTRODUCTION

The designers and constructors of the first nuclear power plants generally followed installation practices al­ready established for conventional process and chemical industries Adapting process instrumentation systems to nuclear power plants was reasonably successful However, nuclear radiation systems had no conventional counter­parts During installation and preoperational tests in nuclear power plants, noise problems were found to be common­place, and extensive modifications to the signal, control, power, and ground cables were required before nuclear radiation instrumentation systems could satisfy the estab­lished safety criteria

Since the nuclear power plants being built today involve many different geometric configurations and a number of different basic materials, it is impractical to recommend a standard installation for all plants However, the material presented here should provide engineers m the design and construction fields with a set of installation practices that will enable them to avoid many problems and pitfalls

10- 2 REACTOR INSTRUMENTATION SYSTEMS

9- 2.1 Control Room

The control room in a nuclear power plant has many features in common with fossil-fueled generating stations Many practices developed in fossil-fueled plants are directly applicable to nuclear plants

The control room should be designed and installed so that it can be safely operated and occupied under any external hazard condition, such as fire, smoke, contami nated atmosphere, flood, seismic disturbance, or major electrical fault

An acceptable nuclear power-plant control-room instal­lation requires not only that equipment and components be integrated into a compatible system capable of the neces­sary overall performance but also that the human operator and his relation to this equipment be considered If the man—machine relation is to provide maximum efficiency m operation, human factors must be considered as part of the initial engineering criteria 1 he control console and panel must be arranged so the reactor can be operated in a reliable manner with a minimum number of personnel

Good design and installation practices dictate that all important variables in the plant operation be available for display and control in the station control room Variables associated with reactor and heat transfer control are gener­ally installed on the mam control console Variables associated with the auxiliary equipment, such as the turbine and generator control, electric switchgear control, and several process-instrumentation control systems, are usually installed on the control panel

A representative control-room installation is shown in Fig 10 1 A plan view of this control room is shown in Fig 10 2

9- 2.2 Control Console

The wraparound control console is widely accepted by the nuclear industry The console shown in Fig 10 1 is one example of good installation practices The accessibility to instruments, switches, controls, and terminal boards at the rear of the console is excellent The console is installed on a base structure that provides a step-down passageway behind the terminal boards and termination points at the rear of the control console Access to this passageway is through the rear doors of the console The passageway is wide enough to accommodate important test equipment, such as oscilloscopes

In some nuclear power plant installations the main control console is incorporated into and made an integral part of the vertical control board (see Sec 10-2 3) Accessibility to instruments, switches, and controls is made at the rear of the vertical control board

The following practices, based on observations of control consoles in several nuclear plants and on experience in nuclear-plant maintenance, are recommended

1 Accessibility to the rear of the console must be provided for maintenance and test

2 All field cabling coming into the control console and cabinets must be brought through a suitable dust seal, such as a penetration sealed by a compound This provision will help to maintain the control room at a slightly higher pressure than ambient to prevent such hazards as fire, smoke, and noxious fumes from spreading into the control center

3 Access must be provided to all components and electrical connections to facilitate maintenance (see also Sec 10 4)