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DSAR CHAPTER 7 - INSTRUMENTATION AND CONTROLS Revision 36 SECTION 7.1 Page 7.1-1 of 7.1-1
7.1 INTRODUCTION
The Facility systems are instrumented to provide information on Facility conditions at selected locations, and to protect equipment and personnel from undesirable conditions. The principal control station for the Facility is in the control room.
Major portions of the instrumentation and controls are located in the control room. The instrumentation is arranged in groups on the control boards so that when corrective action is required, all pertinent indicators, recorders and controllers are within easy reach of the operator. The control board consists of a control console and duplex vertical panels. Visible alarms with audible signals, located on the super-structure over the main control board, annunciate and identify abnormal operating conditions. A telephone system provides both intraplant and external communication.
All instrumentation and control equipment is made from highly reliable components. Seismic qualification of the instrumentation have been the subject of various reports (see Subsections 8.1.3, 8.1.4 and Class 1E classification in Section 5.2).
As described in Section 5.2, following the implementation of Permanently Defueled Technical Specifications, Class 1E is no longer applicable to electric equipment in accordance with 10 CFR 50.49(a).
This chapter describes safety-related as well as major nonsafety-related instrumentation and controls for systems described in other chapters. Special nonsafety-related instrumentation systems such as radiation monitoring, leak detection, fire detection and meteorological instrumentation are outlined in other chapters.
DSAR CHAPTER 7 - INSTRUMENTATION AND CONTROLS Revision 36 SECTION 7.2 Page 7.2-1 of 7.2-2 7.2 REACTOR PROTECTIVE SYSTEM 7.2.1 GENERAL The Reactor Protective System (RPS) was a Class 1E system (with the exception of the clutch power supplies) and is comprised of the sensor instrumentation, amplifiers, trip units, logic circuits, actuation circuits and other equipment.
The RPS controls are housed in four cabinets in the control room. The cabinets consist of the following components:
Four (4) Trip-Inhibit Switch Panel Assemblies Four (4) Trip-Unit Assemblies (One for each channel A,B,C,D)
Twenty Eight (28) Bistable Trip Units (Seven in each channel)
Sixteen (16) Auxiliary Trip Units (Four in each channel)
Four (4) RPS Power Supply Assemblies Four (4) Clutch Power Supply Assemblies Four (4) RPS Bin Assemblies Four (4) Trip Unit Interconnection Modules One (1) Rod Drop Test Panel Four (4) Auxiliary Logic Module Assemblies Four (4) RPS Test Panel Modules The following components are also part of the RPS cabinets and are part of the nuclear instrumentation described in Section 7.6:
Two (2) Nuclear Instrument Source/Wide Range Drawer Assemblies Four (4) Power Range Safety Drawer Assemblies One (1) Comparator Averager Assembly
DSAR CHAPTER 7 - INSTRUMENTATION AND CONTROLS Revision 36 SECTION 7.2 Page 7.2-2 of 7.2-2 Finally, a set of annunciators (non-class 1E) are also located on the above cabinets for operator convenience. An extension of the RPS is housed in an additional panel, also in the control room. This panel contains:
Four (4) Thermal Margin Monitors Four (4) Reactor Power Calibration and Indication Assemblies Another panel in the control room (C12) contains:
Four (4) pressure switch alarms (dual output each, one for PORV logic, one for ATWS logic) 7.2.2 DELETED 7.2.3 SECTION DELETED 7.2.4 DELETED 7.2.5 SECTION DELETED 7.2.6 DELETED 7.2.7 DELETED 7.2.8 DELETED 7.2.9 SECTION DELETED 7.2.10 DELETED
DSAR CHAPTER 7 - INSTRUMENTATION AND CONTROLS Revision 36 SECTION 7.4 Page 7.4-1 of 7.4-2 7.4 OTHER SAFETY RELATED PROTECTION, CONTROL AND DISPLAY SYSTEMS Safety related control and instrumentation systems ensure mitigation of anticipated events such as uncontrolled release of radioactive effluents. The quality classification of the control and instrumentation systems is subject to reevaluation following the implementation of Permanently Defueled Technical Specifications.
7.4.1 DELETED 7.4.2 SECTION DELETED 7.4.3 SECTION DELETED 7.4.4 SECTION DELETED 7.4.5 VENTILATION AND EFFLUENT RELEASES CONTROLS Automatic isolation controls of ventilation and effluent releases are summarized in this subsection. Details of the applicable control systems are given in Section 9.8 and Chapter 11.
7.4.5.1 Deleted 7.4.5.2 Deleted 7.4.5.3 Radwaste Area One radiation monitor provides a ventilation shutdown signal for the area in the event of spillage. The area is maintained under negative pressure to prevent radioactive leakage out of the building with the supply fan and damper shut off while one of the exhaust fans is not shut off. Alarms in the control room warn the operator that one or more radwaste area ventilation fans have tripped off.
7.4.5.4 Fuel Handling Areas The fuel handling areas are provided with radiation monitors to protect against radioactivity releases in the event of a fuel handling accident. Half of the ventilation is automatically shut off. The fuel handling building is then maintained under negative pressure to prevent leakage out of the building with a fan which is not shut off. Upon receiving an alarm from this monitor, the operator can manually trip the ventilation of the area.
7.4.5.5 Waste Gas Decay Tank
DSAR CHAPTER 7 - INSTRUMENTATION AND CONTROLS Revision 36 SECTION 7.4 Page 7.4-2 of 7.4-2 A high-radiation monitoring signal is provided to automatically close the waste gas decay tank discharge valve when the release rate exceeds the limits in the Offsite Dose Calculation Manual.
7.4.6 SECTION DELETED
DSAR CHAPTER 7 - INSTRUMENTATION AND CONTROLS Revision 36 SECTION 7.5 Page 7.5-1 of 7.5-2 7.5 NONSAFETY-RELATED REGULATING CONTROLS 7.5.1 SECTION DELETED 7.5.2 SYSTEM DESIGN 7.5.2.1 Reactor Regulating The primary loop temperature instrumentation consists of:
- 1. Four high level isolated transmitters.
- 2. Two temperature computing stations.
- 3. Two primary coolant loop hot leg temperature alarm/indicators.
- 4. One six-input loop TAVE, TREF and differential temperature recorder.
- 5. One two position switch to select either of the two channels to provide the TAVE signal to the steam dump controller and pressurizer level controllers.
- 6. One digital indicator to display TAVE as selected by the switch.
- 7. Two voltage to current converters.
7.5.2.2 Deleted 7.5.2.3 Deleted 7.5.2.4 Deleted 7.5.2.5 Steam Dump and Bypass The system consists of:
- 1. One steam dump controller located in the Control Room
- 2. Two steam dump controllers (performs tracking in auto mode) at engineered safeguards panel
- 3. Four atmospheric steam dump valves
- 4. One turbine bypass pressure controller located in the Control Room
- 5. One signal auctioneering unit
- 6. One turbine bypass valve
DSAR CHAPTER 7 - INSTRUMENTATION AND CONTROLS Revision 36 SECTION 7.5 Page 7.5-2 of 7.5-2 7.5.2.6 Turbine Generator Controls The controls consist of the following five parts:
- 1. Operators Interface Panel
- 2. Digital Controller & Engineers Console
- 3. Steam valve servo actuator assemblies
- 4. High-pressure fluid supply
- 5. Emergency trip 7.5.3 SECTION DELETED
DSAR CHAPTER 7 - INSTRUMENTATION AND CONTROLS Revision 36 SECTION 7.6 Page 7.6-1 of 7.6-4 7.6 PLANT PROCESS COMPUTER AND MISCELLANEOUS INSTRUMENTATION This section primarily describes nonsafety-related instrumentation.
Safety-related instrumentation are mentioned only for clarity of text.
7.6.1 DESIGN BASES 7.6.1.1 Deleted 7.6.1.2 Deleted 7.6.1.3 Deleted 7.6.1.4 Deleted 7.6.1.5 Palisades Plant Computer (PPC)
This monitoring system is provided to display, print, and store facility process information. Functions provided include Sequence of Events (SOE) monitoring, Safety Parameter Display System (SPDS) and Emergency Response Data-link System (ERDS).
Sequences of events for safety- and non-safety-related Facility parameters of the following systems are monitored, displayed, and recorded.
- 1. Secondary Plant Process Instruments
- 2. Electrical Power Distribution The PPC is a non-class 1E monitoring system.
The PPC includes and conforms to Critical Functions Monitoring System (CFMS) design. This design provides concise display of important parameters to control room operators. The PPC is designed to provide the same information to the Technical Support Center (TSC) and Emergency Operations Facility (EOF) to aid in emergency response management. The CFMS is a Safety Parameter Display System as described in Supplement 1 to NUREG-0737. In a letter dated April 19, 1990 the NRC found the Palisades' SPDS to be acceptable on the basis that it meets NUREG-0737 Supplement 1 requirements (References 11 and 12).
The PPC typically interfaces with historically Class 1E systems through electronic isolation devices, 100K ohm isolation resistors, relay contacts and the CFMS input termination/ multiplexer cabinets located in the control room.
The CFMS input control cabinets are designed to be seismically qualified to the criteria of IEEE 344-1975. The CFMS input cabinets also provide for separation and isolation of Class 1E and Nonclass 1E equipment in accordance with the requirements of IEEE 384-1977.
DSAR CHAPTER 7 - INSTRUMENTATION AND CONTROLS Revision 36 SECTION 7.6 Page 7.6-2 of 7.6-4 The SOE node, Cooling Tower Control System (CTCS) node, PIP node, SPI node and the D204 Battery backed power system include components located in the CP Co Design Class l portion of the auxiliary building and, as such, are required to be housed in cabinets qualified as Seismic Category I per Regulatory Guide 1.29 to prevent damage to other equipment through structural failure. Following the implementation of Permanently Defueled Technical Specifications, damage to other equipment through seismic structural failure is no longer of concern. This system has been classified as functional Nonclass 1E, as such interfaces of Class 1E components with the system must meet IEEE 384-1977 and be in accordance with 10 CFR 50, Appendix A, GDC24.
7.6.2 SYSTEM DESCRIPTION 7.6.2.1 Deleted 7.6.2.2 Nuclear Instrumentation Introduction - The Nuclear Instrumentation System consists of eight channels.
The combined source/wide range channels and power range safety channels are located in the Reactor Protective System cabinet in the control room.
Four cabinets designated as A, B, C and D each house one channel of the protective system. Cabinets A and B each contain one power range channel.
Cabinets C and D each contain one source/wide range channel and one power range safety channel. Mechanical and thermal barriers between the cabinets reduce the possibility of common event failure. The source and wide-range detector cables of a channel originate from the same preamp and are routed in the same cable tray. Each redundant source/wide range channel is separated and fed through different penetrations. The power range safety channel detector cables are routed separately from each other including penetration areas. The nuclear detector locations are shown in Figure 7-60.
7.6.2.3 Deleted 7.6.2.4 Deleted 7.6.2.5 Palisades Plant Computer System Layout - The plant computer consists of four intelligent input nodes, one direct connected multiplexor, multiple display workstations, printers and interconnecting hardware. The plant computer is a distributed system which communicates via Ethernet. There are separate Ethernet cabling systems for the Input nodes and for the Man Machine Interfaces.
The Man-Machine-Interfaces are Computer Workstations. At the very least, there are workstations in the Control Room, TSC, and EOF. The host computer in the CFMS trailer distributes all data to the workstations. Page
DSAR CHAPTER 7 - INSTRUMENTATION AND CONTROLS Revision 36 SECTION 7.6 Page 7.6-3 of 7.6-4 printers are located in the Control Room (CR), TSC, and EOF for prints of the workstation screens and reports from the host computer.
Four input nodes, PIP, SPI, SOE, and CTCS, are combinations of an input multiplexor and a computer. These nodes perform input processing including Analog to Digital Conversion, Sequence of Events time-stamping, and engineering units conversion. This processed data is assembled and passed to the Host computer. The host computer in turn performs alarm processing, event logging, historical recording and database distribution functions based on this data. Two nodes, the PIP and CTCS nodes, perform additional software tasks such that control rod monitoring and Cooling Tower Fans can be operated independent of host computer operability. The host computer runs several custom software modules such as CFMS processing, Incore monitoring, Rod monitoring, Meteorological data interface, and calculated point processing.
Identification of the PPC components and general location is shown in Figure 7-61. The host computer interfaces, Meteorological, EOF, and the backup alarm printer, are located in the CFMS trailer on the turbine deck.
The communications hubs and the SOE node are located in the Cable spreading room below the control room. The control room has at least one permanently located workstation. A page printer is located here. The PIP, SPI, and CTCS nodes are located in the control room also. The Cutler-Hammer input multiplexor is also located in the control room and communicates back to the CFMS trailer directly.
The power supply for the PPC host computer and SOE node includes a 125 volt dc subsystem (one battery, two chargers and one distribution panel) and a dc-to-ac conversion subsystem (two inverters, two static switches) with bypass transformers. Power is taken from the 480-volt MCCs 3 and 4. Only those components required to maintain minimal PPC functionality to the Control room, TSC, and EOF are powered from this system. Extra workstations and non-essential devices are powered from lighting panel power. The CTCS node is powered from the Instrument AC panel Y-01, while the PIP and SPI nodes are powered from the Preferred AC panels Y-20 and Y-40, respectively.
Interfaces - Interfaces with the engineered safeguards controls and the Class 1E electrical distribution system are exclusively digital. They are provided via relay contact inputs from these controls, thus ensuring adequate electrical isolation as required by IEEE 384-1977. Interface with the fluid systems protection is via relay contact to the SOE Node for PRV-1043B and by direct connection from the valve indicating light to the SOE Node for PRV-1042B.
Interfaces with non-safety-related systems (regulating controls, primary and secondary facility process and Nonclass 1E electrical distribution) are both digital and analog. They do not require any special isolation means.
DSAR CHAPTER 7 - INSTRUMENTATION AND CONTROLS Revision 36 SECTION 7.6 Page 7.6-4 of 7.6-4 The PPC is comprised of reliable electronic gear fed from an uninterruptible type of power supply. Being a Nonclass 1E system, all safety systems interfaces have isolation means in accordance with IEEE 384-1977 and GDC24 either via relay coil-contact isolation or qualified electronic isolators.
As described in Section 5.2, components located in the CP Co Design Class 1 portion of the auxiliary building (the PPC cabinets in the cable spreading room, and certain power supply subsystem components in switchgear room 1D), were historically qualified as Seismic Category I (Section 5.7). The system battery enclosure in switchgear room 1D is equipped with a hydrogen evacuation system, V-928, designed to provide a scavenging rate which precludes the formation of an explosive concentration.
The CFMS method or design was carried over from the stand alone CFMS replaced in 1995 into the User interface of the new PPC. The principal software function of the CFMS is to provide concise displays of Facility data, provide for trending of input data and to provide for historical data storage and retrieval. This information is available to system users at each of the various workstations. The CFMS software design provides a hierarchy of displays showing the status of the Plant's critical safety functions. The hierarchy starts with a top-level display showing individual boxes that give an indication of the status of each critical safety function. Lower-level displays give system overviews with current values of important process variables and more detailed mimic diagrams showing system line-up and indicating variables that are in alarm state by use of color of component symbols or variable values.
Displays such as the Critical Function Matrix, event and alarm log, trends and others can be accessed with dedicated function keys on the keyboard. A small representation of the Critical Functions Matrix is visible from every display and indicate the overall status of each critical function.
The PPC provides historical storage and retrieval of Process data in order to assist facility personnel in process trending and post-trip or transient recreations. Historical data can viewed in the form of real-time trends, X-Y plots, and statistical reports. Historical data can be archived to disk or tape for later viewing. Sequence of events logs are also archived.
Additional information on the PPC/CFMS is provided in References 6 and 7.
For Cyber Security requirements, the PPC network is logically isolated from the Palisades site business LAN. All PPC data is sent through a deterministic one-way "Data Diode" to computers on the Business LAN. Computer monitoring tools, on the Business LAN, provide the EOF with monitoring capabilities equivalent to Control Room and TSC. Data sent from the Meteorological Monitoring System to the PPC is isolated through an analog to digital circuit.
The PPC via the "Data Diode", provides data to the NRC's Emergency Response Data-link System (ERDS). This data link is capable of sending a preselected group of PPC input variables to the NRC.
DSAR CHAPTER 7 - INSTRUMENTATION AND CONTROLS Revision 36 SECTION 7.7 Page 7.7-1 of 7.7-5 7.7 OPERATING CONTROL STATIONS 7.7.1 GENERAL LAYOUT The operating control stations consist of the control room for centralized control during facility evolutions and auxiliary stations for normal operation of radwaste and miscellaneous noncritical systems.
Radiation and shielding design of the spaces in which operating personnel occupancy is required, including adequate access to the vital areas for control of the Facility during and after an accident, has been provided. Refer to Chapter 11 for details of radiation zones.
An onsite Technical Support Center (TSC) is located just outside the control room in an extension to the auxiliary building, provided with dedicated communications with the control room and other centers identified in the Palisades Emergency Plan, including a dedicated display terminal from the Plant Process Computer (Subsection 7.6.2.5). The intent of this TSC is to meet NUREG-0696.
7.7.2 CONTROL ROOM The control room is accessible from the auxiliary and turbine buildings and houses the control console, vertical duplex boards, cooling tower boards, and switchyard supervisory boards for operation and monitoring of all critical systems. The control console consists of three sections arranged as follows:
- 1. Center Section - Control devices, indicators and recorders, reactivity regulation, primary coolant components, shutdown cooling and Chemical and Volume Control System.
- 2. Left Section - Control devices, indicators and controllers for the Engineered Safeguards Systems, Service Water System, Component Cooling System and Containment Air Cooling Systems.
- 3. Right Section - Control devices, indicators, recorders and controllers for the main turbine and generator and feedwater control systems.
The vertical board is a totally enclosed walk-in panel. One part of the vertical board is arranged in three connected sections with equipment layout and physical separation similar to the control console. The equipment on the front of the vertical panel is located directly behind the console section having devices for that same system. Other control and monitoring equipment for other systems is located on the back of this board and on separate vertical duplex boards. The annunciators for the entire Facility are located across the top of the vertical panels providing visual and audible indication of off-normal conditions requiring operator action.
DSAR CHAPTER 7 - INSTRUMENTATION AND CONTROLS Revision 36 SECTION 7.7 Page 7.7-2 of 7.7-5 A program to review the human factors of the control room was initiated in late 1980 in response to NUREG-0660 and NUREG-0737, Supplement 1, and consistent with the guidance provided by NUREG-0700. The objective, as stated in NUREG-0660 was to improve the ability of control room operators to prevent accidents or to cope with them, should they occur, by improving the information provided to them.
Short-term improvements were completed during the 1983 refueling outage while long-term improvements were scheduled for subsequent outages. On September 14, 1989 the NRC issued a final SER on the program. Based on review of the CP Co Summary Report submitted on August 29, 1986 and onsite inspections, the SER concluded that the Palisades Facility meets all the requirements of Supplement 1 to NUREG-0737 for the Detailed Control Room Design Review.
Control console and panel sections listed in Table 5.7-7 and containing Class 1E devices are designed to withstand seismic loads described in Section 5.7. All other panels and equipment in the control room have been anchored to stay in place during a seismic event (see Section 5.10).
The control room is located in the CP Co Design Class 1 portion of the auxiliary building. Sufficient concrete shielding is provided to ensure safe occupancy of the control room during all normal and abnormal Facility conditions. The control room atmosphere is air-conditioned for personnel comfort and equipment cooling using redundant HVAC with historically Class 1E controls (see Section 9.8). The ventilation system is arranged for outside makeup air to be drawn through absolute and charcoal filters. The control room area is provided with an area radiation monitor.
All materials of construction used in the control room are noncombustible.
Electrical wiring is flame-retardant as proven by applicable vertical flame tests.
Control Room Protection Against Fire Cables related to control cabinets and consoles penetrate the floor directly into control panels and consoles.
The combustibles in the area consist mainly of electrical wiring insulation contained within the cabinets and a small amount of ordinary combustibles such as paper. An unmitigated fire in one of the control panels would probably be limited to one panel involving only one division of safe shutdown equipment due to the low combustible loading and the physical separation and barriers provided.
In addition, smoke detectors are installed in the walk-in cabinet enclosures and throughout the ceiling of the control room and adjacent offices. Smoke detectors are not installed in the main control consoles since they are
DSAR CHAPTER 7 - INSTRUMENTATION AND CONTROLS Revision 36 SECTION 7.7 Page 7.7-3 of 7.7-5 designed with outlet ventilation openings at the top which will allow the control room personnel to observe any smoke present from a fire.
Other fire protection features are described in the Fire Safety Analyses (Section 9.6.3) for this area.
The control room ventilation system can be controlled manually by the control room personnel and will allow shutoff of the fans if smoke was observed entering the control room. Manual operation of the ventilation system for venting the control room is also available.
All cable penetrations into the control room have been sealed with flame-retardant material.
There are no concealed floor or ceiling spaces that contain cables in the control room (area over panels, only).
The control room is not used as a cable right of way.
7.7.3 ENGINEERED SAFEGUARDS AUXILIARY PANEL (C-33)
The engineered safeguards auxiliary panel is located in the auxiliary building.
7.7.4 AUXILIARY HOT SHUTDOWN CONTROL PANELS (C-150/C-150A)
Auxiliary Hot Shutdown Control Panels (C-150/C-150A) have been provided and located in the southwest electrical penetration room. These panels are comprised of two enclosures, the main enclosure C-150 and an auxiliary one called C-150A.
7.7.5 RADWASTE SYSTEM LOCAL CONTROL PANEL The Radwaste System control panels are located in the auxiliary building and are accessible through the Access Control. These panels contain all the control and monitoring devices to initiate, control and monitor the Radwaste System components.
7.7.6 MISCELLANEOUS LOCAL CONTROL STATIONS Miscellaneous noncritical systems are controlled from local stations throughout the Facility.
Off-normal conditions in all systems are alarmed on the respective local panel and on the main control panel annunciators.
DSAR CHAPTER 7 - INSTRUMENTATION AND CONTROLS Revision 36 SECTION 7.7 Page 7.7-4 of 7.7-5 7.7.7 FEATURES WHICH ENHANCE SAFE OPERATION Steel fire barriers are incorporated in the main control console, main control panel, and engineered safeguards auxiliary panel. The barriers are arranged to separate control circuits similar to the separation of equipment power supplies.
All panels and consoles are totally enclosed and constructed from steel plate welded to steel frames. Fire retardance and rigidity for mounted equipment and cabling is provided by this construction.
7.7.8 IN-PLANT COMMUNICATION SYSTEM The in-facility communication system is comprised of five subsystems: a telephone system, a public address system, an intercommunications system, a sound-powered phone system and an onsite/offsite radio system.
Paging over a Facility-wide public address system is initiated by dialing a preselected number from any of the telephone stations. Facility-wide paging can also be accomplished by a microphone in the control room. Paging from the control room station overrides paging from any other station.
An intercommunications system permits common talking between the control room and the fuel pool area as an aid in the fuel handling operation. A closed circuit television system with a screen in the control room aids in monitoring fuel handling.
The sound-powered phone system is intended for equipment test and calibration which require vocal communication between the equipment and control room. It can be used also by personnel in the Technical Support Center during an emergency.
The onsite/offsite radio system includes a base station in the turbine building, a remote base station in the control room for onsite communication with portable transceivers. A repeater unit is located onsite for use by security personnel.
Communications between personnel performing manual actions and those providing feedback are not a requirement but rather an enhancement.
7.7.9 OUT-OF-PLANT COMMUNICATION SYSTEM The telephone system provides normal external communications for the Facility.
Additional offsite communications are provided by the onsite/offsite radio system. This system has offsite communications with the Emergency Operations Center and with a repeater in the site emergency vehicle.
DSAR CHAPTER 7 - INSTRUMENTATION AND CONTROLS Revision 36 SECTION 7.7 Page 7.7-5 of 7.7-5 Direct communications with the Michigan State Police are by means of a base station located in the secondary security alarm station. A second remote station is located in the central security alarm station.
All emergency communications are addressed in the Emergency Plan.