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DSAR CHAPTER 9 - AUXILIARY SYSTEMS Revision 36 SECTION 9.1 Page 9.1-1 of 9.1-2 9.1 SERVICE WATER SYSTEM 9.1.1 DESIGN BASIS The Service Water System is designed to supply lake water as the cooling medium for removal of waste heat from auxiliary systems. Separate service water lines serve the Plant critical and noncritical systems. The critical system is divided into two electrically independent trains that provide equivalent cooling, which are CP Co Design Class 1 to support Spent Fuel Pool Cooling via the Component Cooling System. The service water pumps are located in the CP Co Design Class 1 portion of the intake structure.
9.1.2 SYSTEM DESCRIPTION AND OPERATION 9.1.2.1
System Description
Three half-capacity electric motor-driven pumps draw screened and intermittently chlorinated Lake Michigan water from the intake structure (Figure 9-1). Two motors are connected to one 2.4 kV bus and the third motor is connected to a separate 2.4 kV bus. Each pump can be started or stopped remotely from the main control room or locally at the switchgear.
Each service water pump discharges through a simplex strainer into a common header. Each pump can be isolated from this header by a manually-operated valve in the pump discharge.
The common header of the service water pumps has a full-capacity takeoff at each end which supplies critical Plant systems. A third takeoff at one end of the common header supplies the noncritical auxiliary systems.
The two critical service water lines run underground by different paths from the intake structure to the auxiliary building. The two lines are joined in the auxiliary building by a double-valved crosstie. Each line has an isolation valve upstream of the crosstie valves. These four valves permit the isolation of either critical line. Each valve is a fail open, piston-operated type and can be actuated remotely from the main control room or manually by a local handwheel.
Upstream of the crosstie valves, each line supplies cooling water to emergency diesel generator lube oil and jacket water coolers, a control room air-conditioning unit, and an engineered safeguards room cooler. In addition, Train A supplies cooling water to the component cooling water heat exchangers.
The service water discharge from equipment carrying potentially contaminated fluid is continuously monitored for radioactivity, enabling radioactive leakage into the service water to be detected before service water is released to the lake.
DSAR CHAPTER 9 - AUXILIARY SYSTEMS Revision 36 SECTION 9.1 Page 9.1-2 of 9.1-2 Provisions are made to connect the fire system to the Service Water System as a partial backup.
Provisions exist to replenish the Spent Fuel Pool (SFP) from the Service Water System.
Systems supplied by the Service Water System and cooling water flow requirements for equipment supplied by the Service Water System are tabulated in Table 9-1.
In response to Generic Letter 89-13, a program was established to address the issue of biofouling of the service water system. Elements of this program include periodic inspections of the service water pump intake bay and service water system components, chlorination of service water, periodic flushing of infrequently used cooling loops and periodic verification of service water system flow rates and heat exchanger heat transfer capabilities (see Reference 6).
9.1.2.2 Component Description Design ratings of components in this system are given in Table 9-2.
9.1.2.3 System Operation Two service water pumps are required to furnish the normal cooling water demand; the third pump will normally be on standby. Two pressure switches are provided in the discharge of each pump connecting to the starting circuits of the remaining two pumps. If the service water pressure falls below a preset value, one of the switches initiates automatic starting. The auto-start feature is automatically reset on bus undervoltage to prevent cycling the pump breaker onto a dead bus.
If the SW header pressure reaches a predetermined low pressure corresponding to low flows to the various components the operators are procedurally instructed to restore service water and if necessary can align the Fire System to the Service Water System and start a fire pump.
9.1.3 SECTION DELETED
DSAR CHAPTER 9 - AUXILIARY SYSTEMS Revision 36 SECTION 9.2 Page 9.2-1 of 9.2-2 9.2 REACTOR PRIMARY SHIELD COOLING SYSTEM 9.2.1 DESIGN BASIS Following the implementation of Permanently Defueled Technical Specifications, the Reactor Primary Shield Cooling System information herein is considered historical and does not constitute design requirements unless otherwise noted to still be applicable in the defueled condition.
The reactor Shield Cooling System is designed to CP Co Design Class 3 standards.
9.2.2 SYSTEM DESCRIPTION AND OPERATION 9.2.2.1
System Description
The Shield Cooling System is a closed loop system consisting of two full-capacity sets of cooling coils, two full-capacity pumps, a heat exchanger, a surge tank, associated piping, valves, instrumentation and controls as shown on Figure 9-2.
All components of the system are located within the containment building.
Each set of shield cooling coils is composed of individual cooling coils embedded in the concrete shield. The distance between the inner surface of the concrete and center line of cooling coils is three inches.
The supply header to each set of cooling coils is provided with a diaphragm operated, fail-open valve operated from the main control room. A check valve is provided in the discharge header for each set of coils to prevent flow from the coils in service into the coils which are out of service.
The closed loop system transfers heat to the Component Cooling Water System by means of the shield cooling heat exchanger. Demineralized water with a corrosion inhibitor is used in the shield cooling loop.
9.2.2.2 Component Description Design ratings and design features of components of the system are given in Table 9-3.
9.2.2.3 System Operation During operation, one shield cooling pump and one set of cooling coils are in continuous service. The idle pump is in standby. The normal flow through the shield cooling coils is from 134 to 154 gpm. The shield cooling heat exchanger is in continuous service with the shield cooling water flowing through the tubes and component cooling water through the shell.
DSAR CHAPTER 9 - AUXILIARY SYSTEMS Revision 36 SECTION 9.2 Page 9.2-2 of 9.2-2 Both pumps can be started and stopped from the main control room. The standby pump starts automatically on low discharge header pressure.
The surge tank is installed at elevation 649 feet 0 inches in order to maintain an approximately constant suction head of 27 psig on the pumps. Makeup water to the tank is normally pumped from the primary system makeup storage tank through an on-off solenoid valve which is actuated by a level switch on the surge tank. The condensate storage tank can be used as an alternate makeup supply. High and low level in the tank is annunciated in the control room. The tank vents directly to the containment atmosphere and this protects the tank from overpressurization.
The temperature of the shield cooling water is regulated by manual adjustment of the component cooling water outlet header butterfly valve.
Temperature indication, high temperature (120°F) and low flow annunciation from the discharge of each set of coils are located in the control room. Both pumps can supply cooling water to either set of coils.
9.2.3 SECTION DELETED
DSAR CHAPTER 9 - AUXILIARY SYSTEMS Revision 36 SECTION 9.3 Page 9.3-1 of 9.3-3 9.3 COMPONENT COOLING SYSTEM 9.3.1 DESIGN BASIS The Component Cooling Water System, Figure 9-7, is designed to cool components carrying radioactive and potentially radioactive fluids. It provides a monitored intermediate barrier between these fluids and the Service Water System which transfers the heat to the lake. Thus, the probability of leakage of contaminated fluid into the lake is greatly reduced.
System components are rated for the maximum facility heat removal requirements. The system is designed to CP Co Design Class 1 requirements except for some non-safety related portions of the system.
9.3.2 SYSTEM DESCRIPTION AND OPERATION 9.3.2.1
System Description
The system is a closed loop consisting of three motor-driven circulating pumps, two heat exchangers, a surge tank, associated valves, piping, instrumentation and controls. The Component Cooling System is shown on Figure 9-7. The system is continuously monitored by a process monitor which detects radioactivity which may have leaked into the system from the fluids being cooled.
The component cooling pump motors are connected to two separate 2,400 volt buses, with one pump on one bus and the remaining two on the other. The pumps can be started and stopped from the main control room and also locally at the switchgear.
System volume expansion and contraction are accommodated by an elevated surge tank which also maintains a constant static head of approximately 28 psi on the pump suctions. The system can be vented to the auxiliary building through a diaphragm-operated three-way valve on the surge tank. The auxiliary building in turn vents to the outside atmosphere through the Plant ventilation exhaust stack. The other port on the three-way valve is connected to the vent gas collection header and is automatically transferred in the event the Component Cooling System contains radioactive gases due to leakage from radioactive systems being cooled. A relief valve discharging to the liquid radwaste system is provided on the surge tank to protect from overpressure.
The Component Cooling Water System uses demineralized water to which an inhibitor is added for corrosion control. Makeup to the system is automatically supplied from the primary system makeup storage tank.
Heat is transferred from the system to Plant service water by means of two component cooling heat exchangers. Cooling requirements are shown on Table 9-4. Service water from the critical service water-header is provided to the tube side of the heat exchangers and the rejected heat from the system is discharged by service water into the cooling tower makeup basin.
DSAR CHAPTER 9 - AUXILIARY SYSTEMS Revision 36 SECTION 9.3 Page 9.3-2 of 9.3-3 A supply line is provided to the Spent Fuel Pool Heat Exchangers and Radwaste Equipment.
The supply line to the Spent Fuel Pool Heat Exchangers and Radwaste Equipment has a supply valve that can be operated from the control room.
The downstream supply line to the Radwaste Equipment has a supply valve operable from the Engineered Safeguards Auxiliary Panel.
9.3.2.2 Component Description Construction features of system components are given in Table 9-5.
Material for components, connecting piping and valves in contact with component cooling water is carbon steel, cast iron or bronze.
9.3.2.3 System Operation Flow requirements for various operational modes are shown in Table 9-6.
During normal operation following the implementation of Permanently Defueled Technical Specifications, component cooling pumps and the two component cooling heat exchangers will be in service as necessary to support cooling of the Spent Fuel Pool. The pump(s) runs continuously with the other pump(s) in "Standby." The number of pumps running is determined by the discharge header pressure.
The temperature of the component cooling water at the heat exchanger discharge is controlled between 72 °F and 90 °F by regulation of the service water flow. Gross adjustment required by seasonal temperature variations in the service water temperature is achieved by adjustment of hand indicating controllers (HICs), which position the heat exchanger service water outlet butterfly valves. Short-term fluctuations in CCW temperature are addressed by automatic temperature control of the rotary valves that bypass the butterfly valves. High/low component cooling temperature is annunciated in the control room. The CCW and service water discharge temperature from each component cooling heat exchanger is indicated in the control room.
Makeup to the Component Cooling System is pumped to the surge tank from the primary system makeup storage tank through an automatic on-off diaphragm-operated valve which is actuated by a level switch on the surge tank. Tank low level is annunciated in the control room. Chemicals for corrosion control are added to the component cooling water chemical addition tank. By recirculation of cooling water through a recirculating header connecting the discharge header to the chemical addition tank, the chemical solution flows from the tank into the pump suctions where it mixes with the component cooling water and is gradually distributed throughout the Component Cooling System.
DSAR CHAPTER 9 - AUXILIARY SYSTEMS Revision 36 SECTION 9.3 Page 9.3-3 of 9.3-3 A radiation monitor in the pump discharge header detects radioactive inleakage into the CCW system from components being cooled. High activity is annunciated in the main control room. If the radioactivity level in the system reaches a preset level above normal background as detected by the radiation monitor, the three-way valve on the surge tank, if open to room atmosphere, is automatically closed to room atmosphere and opened to the vent gas collection header which is a portion of the gaseous radwaste treatment system.
9.3.3 DESIGN ANALYSIS 9.3.3.1 Deleted 9.3.3.2 Provisions for Testing and Inspection Each pump was shop-tested in accordance with requirements of the Standards of Hydraulic Institute. The heat exchangers were each hydrostatically tested in accordance with the requirements of the ASME B&PV Code,Section III, Class C, 1965. Valve bodies were hydrotested in accordance with requirements of AWWA-C504.
DSAR CHAPTER 9 - AUXILIARY SYSTEMS Revision 36 SECTION 9.4 Page 9.4-1 of 9.4-3 9.4 SPENT FUEL POOL COOLING SYSTEM 9.4.1 DESIGN BASIS The spent fuel pool cooling system removes decay heat from spent fuel stored in the spent fuel pool. The system was originally designed to remove the decay heat from one-third of the total core fuel elements.
The spent fuel pool cooling system is required to maintain the fuel pool water temperature less than 150qF with a minimum of one spent fuel pool cooling pump operating. The maximum spent fuel pool heat load resulting from off-loaded spent fuel shall be less than 28.64 x 106 Btu/hr regardless of whether the heat load is from a one-third core off-load or a full core off-load. A heat load less than 28.64 x 106 Btu/hr ensures that the spent fuel pool water temperature limit of 150qF is maintained with one pump in operation. Heat is removed from the spent fuel pool by the spent fuel pool heat exchanger with component cooling water providing the cooling medium.
The replacement spent fuel storage racks installed in 2013 (refer to Section 9.11) have a maximum potential heat load of 28.9 x 106 Btu/hr (Reference 9.78). The administratively controlled limit, per this section, remains 28.64 x 106 Btu/hr.
The fuel handling area, including the spent fuel pool, is a CPCo Design Class 1 structure and the spent fuel pool cooling system is a CPCo Design Class 1 system and is tornado protected, except as noted.
9.4.2 SYSTEM DESCRIPTION AND OPERATION 9.4.2.1
System Description
The fuel pool cooling system is a closed loop system consisting of two pumps, a heat exchange unit consisting of two heat exchangers in series, a bypass filter, a bypass demineralizer, a booster pump, piping, valves and instrumentation. The bypass filter element was removed from the housing due to ALARA concerns; refer to Section 11.6.4.3 for details. The spent fuel pool cooling system is shown on Figure 9-8.
Materials used in the spent fuel pool cooling system are suitable for use with borated water (2% by wt boric acid). Fuel pool makeup water may be supplied from the Primary System Makeup Storage Tank (T-90), or Service Water System. In the event of a considerable loss of pool water, the fire system can be used to replenish the pool water content.
The clarity and purity of the water in the spent fuel pool are maintained by passing a portion of the flow through the bypass filter and/or demineralizer.
Skimmers are provided in the spent fuel pool to remove accumulated dust
DSAR CHAPTER 9 - AUXILIARY SYSTEMS Revision 36 SECTION 9.4 Page 9.4-2 of 9.4-3 from the pool. The skimmers have experienced leakage and are not normally used. A floating filter is used periodically instead.
9.4.2.2 Component Description Design ratings and construction of components are shown in Table 9-7.
9.4.2.3 System Operation During system operations, one of the two pumps is operated. The pumps are started and stopped from the main control room. A pressure switch on the discharge header annunciates low header pressure in the main control room.
A manually controlled booster pump provides flow through the fuel pool demineralizer. The flow is regulated by manual valve adjustment.
9.4.3 DESIGN ANALYSIS 9.4.3.1 Margins of Safety The analysis of the spent fuel pool cooling system (Reference 73) determined that, assuming a heat load of 28.64x106 Btu/hr, a heat transfer area of 3163.6 ft2 would still maintain adequate heat removal capacity. This corresponds to 140 tubes per heat exchanger plugged. The following chart shows the offload scenario (hypothetical) that bounds normal one-third core or full core offloads:
Parameter Value Heat Load, Btu/h 28.64 x 106 Spent Fuel Pool Pump Flow (one pump), gpm 1530 Component Cooling Water Flow, gpm 1800 Spent Fuel Pool Inlet Temperature, qF 149.4 Component Cooling Water Inlet Temperature, qF 90 Heat Transfer Area, ft2 3163.6 Heat Transfer Coefficient, Btu/hr ft qF 300 NOTE:
Failure of the outlet piping system would result in draining of the fuel pool to the outlet level which still maintains an adequate level of water in the pool for shielding and cooling requirements. Such a failure could occur as a result of
DSAR CHAPTER 9 - AUXILIARY SYSTEMS Revision 36 SECTION 9.4 Page 9.4-3 of 9.4-3 a wind or tornado generated missile striking a portion of the spent fuel pool cooling pump P-51B discharge piping that extends above the spent fuel pool building floor.
Failure of the inlet piping would result in no loss of water from the fuel pool as there is no downcomer by which a siphon could be started.
9.4.3.2 Deleted
DSAR CHAPTER 9 - AUXILIARY SYSTEMS Revision 36 SECTION 9.5 Page 9.5-1 of 9.5-4 9.5 COMPRESSED AIR SYSTEMS Following the implementation of Permanently Defueled Technical Specifications, the Compressed Air Systems information herein is considered historical and does not constitute design requirements unless otherwise noted to still be applicable in the defueled condition.
The Compressed Air Systems consist of the Instrument Air System, the High Pressure Air System, various backup systems, and the Feedwater Purity Air System.
9.5.1 INSTRUMENT AIR SYSTEM 9.5.1.1 Design Basis The Instrument Air System is a non-safety related system that is required for plant operations. The system is designed to provide a reliable supply of dry, oil-free air for instruments and controls, and for service air requirements. The original design of the system was based on an estimated instrument air consumption rate of 80 scfm for the Nuclear Steam Supply System and 115 scfm for the remainder of the Plant.
9.5.1.2
System Description
Three 288 scfm (C-2A, C-2B and C-2C) oil-free air cooled compressors are provided, each with an in-line air receiver tank. The air receivers are connected to a common discharge air header. The common air header branches into two separate air headers, one to the instrument air dryer and filter assembly, and one to the Service Air System. The system is shown on Figure 9-9.
The instrument and service air headers are divided into branch lines supplying the Turbine Building, the Containment Building, the Intake Structure, and the Auxiliary Building.
An isolation valve in series with a check valve is located in the instrument air line outside the Containment Building.
9.5.1.3 Component Description Design ratings and construction of components are shown on Table 9-8.
9.5.1.4 System Operation A continuous supply of a minimum of 80 psig instrument air is provided to hold power-operated valve actuators in the positions required for operating conditions and to provide air for modulating control valves. One of the two equipment lineups described below will normally be in service.
DSAR CHAPTER 9 - AUXILIARY SYSTEMS Revision 36 SECTION 9.5 Page 9.5-2 of 9.5-4
- 1.
The control switch for a compressor (C-2A, C-2B or C-2C) will be placed in the HAND or operating position and supplying Plant loads with one of the remaining two compressors (C-2A, C-2B or C-2C) in the AUTO or standby position. The third compressor can be placed in either the AUTO position or the OFF position as desired by Operations. One Feedwater Purity Air Compressor (C-912A or C-912B) will be operating at a variable speed in response to variations in the pressure in the Feedwater Purity Air Receiver Tank. The other Feedwater Purity Air Compressor is in auto start on bias pressure differential. Feedwater Purity is not cross-tied to the Plant Air System.
- 2.
C-2A, C-2B, and C-2C are either unavailable or in the same configuration as lineup 1 above. Feedwater Purity Air Compressors C-912A and C-912B are in the same configuration as lineup 1.
Feedwater Purity is cross-tied to the Plant Air System supplying both Feedwater Purity and Plant Air Systems.
The standby compressor(s) (C-2A, C-2C or C-2B) start when pressure in the air receiver discharge header drops to 92 psig. Each of the air compressors can be started, set on standby, or tripped by a separate control switch in the Main Control Room.
The standby compressor (C-912A or C-912B) start when predetermined bias pressure is reached between the two Feedwater Purity Air Compressors. The Feedwater Purity Air Compressors C-912A and C-912B control switches are located in the Feedwater Purity Building, however, controls for allowing Feedwater Purity Air to be cross-tied to the Plant air system are located in the control room.
The instrument air header downstream of the filters has a pressure switch which initiates the closing of a shutoff valve on the service air header in the event that the instrument air pressure drops to 85 psig. In addition, low pressure is alarmed in the control room.
9.5.1.5 Design Analysis
- a.
Design Margin (Historic)
The three air compressors in the Instrument Air System are each rated to deliver 288 scfm. The total system design requirement is 195 scfm.
- b.
Provisions for Testing and Inspection Each compressor can be tested to ensure operability with manual "on-off" switches located in the Main Control Room (one switch for each compressor).
DSAR CHAPTER 9 - AUXILIARY SYSTEMS Revision 36 SECTION 9.5 Page 9.5-3 of 9.5-4 9.5.2 HIGH PRESSURE AIR SYSTEM 9.5.2.1 Design Basis The historically safety related portion of the High Pressure Air System in the East and West Safeguards Rooms extends from the air receivers to the control valves serviced and is isolated from the non-safety related portion by check valves. Following the permanent defueling of the facility, the HPA system does not provide air to any safety-related valves and is no longer safety related.
The portion of the High Pressure Air System in the Turbine Building is not a safety related system.
9.5.2.2
System Description
The High Pressure Air System, shown on Figure 9-10, consists of three high-pressure, oil lubricated air compressors, each with its own air dryer and air receiver. Moisture is removed from the high-pressure air by air dryers that are in series with the compressors air-cooled aftercooler. Any remaining moisture is removed by periodic blowdown of the air receivers and the low point drains.
9.5.2.3 Component Description Design ratings and construction of components are shown on Table 9-8.
9.5.2.4 System Operation Each high-pressure air compressor operates automatically to maintain a pressure between 310 and 325 psig in its individual receiver tank.
9.5.2.5 Deleted 9.5.3 BACKUP SYSTEMS The backup systems consist of bottled nitrogen stations, a bottled air station, bulk nitrogen, local accumulators, and manual valve actuators.
9.5.3.1 Design Basis There are six nitrogen backup stations which are connected to the air lines via check valves.
Some valves are equipped with manual valve actuators to permit valve actuation following a loss of motive power.
DSAR CHAPTER 9 - AUXILIARY SYSTEMS Revision 36 SECTION 9.5 Page 9.5-4 of 9.5-4 9.5.3.2
System Description
The nitrogen and air backup stations are shown on Figure 9-9, Sheet 2.
9.5.3.3 Component Description Design ratings of nitrogen backup bottles are shown on Table 9-8.
9.5.3.4 Deleted 9.5.3.5 Deleted 9.5.4 FEEDWATER PURITY AIR SYSTEM 9.5.4.1 Design Basis The Feedwater Purity Air System is not a safety related system. When manually aligned, the system is capable of supplying air to the Instrument and Service Air System.
9.5.4.2
System Description
The Feedwater Purity Air System is supplied by two air compressors, each with an integral intercooler, air dryer, and after-cooler and one common receiver. This system is independent of the other compressed air systems at the Plant but can be tied into the Instrument and Service Air header. When tied to the Instrument and Service Air Systems header, Feedwater Purity air is piped directly to the service air header but the instrument air supply is routed through a dryer. The compressors are air cooled and can provide clean, dry air via the Feedwater Purity air system cross-connect.
9.5.4.3 Component Description Design ratings and construction of components are shown on Table 9-8.
9.5.4.4 System Operation The air compressors operate automatically to maintain approximately 115 psig in the air receiver tanks 9.5.5 RADWASTE AREA COMPRESSOR The Radwaste Area Compressor C-15 is not safety related. C-15 is capable of supplying 220 scfm of air at 125 psig pressure. It was designed to supply air to the Radwaste Volume Reduction System. If necessary, C-15 can be aligned to provide air to the service air system under off-normal conditions.
This can also be used for breathing air by the workers in the containment.
DSAR CHAPTER 9 - AUXILIARY SYSTEMS Revision 36 SECTION 9.6 Page 9.6-1 of 9.6-7 9.6 FIRE PROTECTION 9.6.1 DESIGN BASIS Fire protection uses a defense-in-depth concept to provide a high degree of safety. The plant is designed to prevent fires, detect and suppress fires quickly, limiting their damage, and preventing safe shutdown functions and systems from being interrupted.
Fire Protection systems are designed in accordance with the guidance of the National Fire Protection Association, the American Insurance Association, NEPIA (now American Nuclear Insurers), and the applicable codes and regulations of the State of Michigan.
The primary objective of the fire protection program is to minimize both the probability and consequences of postulated fires. Fires are expected to occur, therefore, means are provided to detect and suppress fires with particular emphasis on providing passive and active fire protection of appropriate capability and adequate capacity for the systems necessary to maintain safe and stable conditions with or without offsite power. For safe and stable systems, fire protection ensures that a fire would not cause the loss of function of such systems, even though loss of redundancy within a system may occur as a result of the fire.
In plant areas where the potential for fire damage may jeopardize safe and stable conditions, the primary means of fire protection consists of fire barriers and fixed automatic fire detection and suppression systems. However, total reliance is not placed on a single fire suppression system. Appropriate backup fire suppression capability is provided throughout the plant to limit the extent of fire damage. Portable equipment consisting of fire hoses, nozzles, portable extinguishers, personnel protective equipment, and air breathing equipment is provided for use by the trained fire brigade. Access to the manual application of fire extinguishing agents to combustibles is provided.
The fire suppression water system may also provide backup water supply to service water and the spent fuel pool fill. The fire pumps are housed in the Class 1 portion of the screen house. A cross connection connects the fire pump discharge header to each of the critical service water header lines.
Both of the above cross connections are protected from tornadoes. A header terminating in a blind flange is provided in the spent fuel pool heat exchanger room for emergency filling of the spent fuel pool. The fire pump test header also has a direct cross-tie to the screen wash header to provide an alternate source of water to clean the traveling screens.
DSAR CHAPTER 9 - AUXILIARY SYSTEMS Revision 36 SECTION 9.6 Page 9.6-2 of 9.6-7 The diesel engine driven fire pumps and the piping connecting the fire suppression water system to the auxiliary feedwater system are designed to Consumers Design Class 2 requirements (except for the piping from the diesel driven fire pump P-41, which is Consumers Design Class 3 but evaluated for seismic loads) (see Subsection 5.2.1.2). The remainder of the system is designed to Consumers Design Class 3 requirements. Appropriate valving is provided to separate the system if required.
A fire brigade of at least five members is maintained on site at all times, except for unexpected absences when the composition may be less than the minimum for a period of time not to exceed two hours. The fire brigade will not include three members of the minimum shift crew necessary for maintaining safe and stable conditions or any personnel required for other essential functions during a fire emergency. Personal protective clothing and air breathing apparatus are provided for the brigade. Fire brigade qualifications and training are described in plant procedures. The fire brigade training program, as practical, meets or exceeds the requirements of NFPA 600-2000.
9.6.2 SYSTEM DESCRIPTION AND OPERATION 9.6.2.1
System Description
Building structures have been designed and arranged to prevent the spread of fire and ensure integrity of redundant safe and stable systems and areas.
A complete description of fire areas, barriers, and means of fire protection is detailed in the Fire Safety Analyses within the NFPA Fire Protection Program (Reference 43).
The fire water system is shown in Figure 9-11. Fire suppression is provided by fixed water spray systems, including sprinklers systems, deluge systems, fire hose reels and cabinets. These fire suppression provisions are found throughout the plant site. The fire hydrant piping system is designed, installed and tested in accordance with the guidance of NFPA 24-1965, Outside Protection. The pumping supply system and fire pumps are designed and installed in accordance with NFPA 20-1966, Installation of Centrifugal Fire Pumps. NFPA 20-1972 was specified for procurement of the second diesel engine driven fire pump.
Fire hoses from fire hydrants and a standpipe system will provide protection in accordance with the guidance of NFPA 14-1963, NFPA 20-1966, and NFPA 24-1965. The standpipe system is designed, installed and tested as a Class II system in accordance with the guidance of NFPA 14-1963, Installation of Standpipe and Hose Systems. Readily accessible rack or reel mounted fire hose lines with electrically safe fog-type nozzles are located throughout the Plant. All areas in the turbine building and auxiliary building which contain or expose safety related systems are within effective firefighting range of at least one hose station.
DSAR CHAPTER 9 - AUXILIARY SYSTEMS Revision 36 SECTION 9.6 Page 9.6-3 of 9.6-7 Fixed water spray systems, such as wet pipe fusible link sprinkler systems, dry pipe fusible link sprinkler systems, and fixed fog deluge spray systems are designed, installed and tested in accordance with the guidance of NFPA 13-1968, Installation of Sprinkler Systems and NFPA 15-1962, Water Spray Fixed Systems for Fire Protection. Water Flow Alarms provide fire detection and indication of individual system water flow in various areas, and is indicated on an annunciator panel in the main control room.
Fixed fog deluge systems protect the main, start-up and station auxiliary transformers. Each of these deluge systems are automatically actuated and annunciated by a general alarm in the main control room. A manual operated fixed fog deluge system protects the charcoal filters used to maintain the control room habitability.
The wet pipe and dry pipe fusible link sprinkler systems are provided in selected plant areas as identified in the Fire Safety Analyses. Actuation of any sprinkler system is annunciated by a general alarm in the main control room.
Fire detection is provided in the form of smoke and ultraviolet detectors.
These detectors were located and installed in accordance with the guidance of NFPA 72E-1974, except inside containment at the electrical penetrations where detectors are placed in proximity to the areas of highest combustible loading. The fire detectors are located in selected plant areas as identified in the Fire Safety Analyses and listed in Table 9-10. Initiation of any of these detector zones alarms is on the annunciator panel located in the main control room and in Switchgear Room 1D. Water flow switches are also provided to indicate actuation of a sprinkler system.
9.6.2.2 Component Description Water for the fire suppression system is supplied by one of three full capacity fire pumps. Each fire pump is capable of providing water to the largest system demand plus fire hose streams in the area of demand. One fire pump is electrically driven, and the other two are diesel engine driven. Any fire pump will start automatically and can be manually started from the pump control panel. The diesel engine driven fire pumps can also be manually started from the main control room.
A jockey fire pump with local controls is provided to maintain the fire suppression system full and pressurized.
Smoke detectors are provided as described in the Fire Safety Analyses and listed in Table 9-10. There is an ultraviolet fire detection system installed in the screen house. The fire detection control panel (C-132) has battery backup and along with the detectors gives alarm annunciation to the control room for a fire throughout the area. The ultraviolet detectors should eliminate nuisance alarms that could be generated by other types due to the heat from the exhaust system of the diesel driven fire pumps in the room.
DSAR CHAPTER 9 - AUXILIARY SYSTEMS Revision 36 SECTION 9.6 Page 9.6-4 of 9.6-7 Portable fire extinguishers are provided at convenient and accessible locations. The extinguishing media are pressurized water, carbon dioxide, or dry chemical as appropriate for the service requirements of the area.
Electric cable fire protection is provided by approved fire barriers and fire stops, in addition to the above fire detection and automatic sprinkler systems where needed to augment separation requirements. See Section 8.5 for details of cable separation requirements.
9.6.2.3 System Operation The motor driven fire pump starts automatically on low fire system header pressure of 98 psig. The first diesel engine driven fire pump starts upon a pressure drop to 83 psig and then the second diesel driven fire pump starts upon a further drop in pressure to 68 psig. The diesel driven fire pumps are thus arranged to back up the motor driven fire pump in case the latter does not start. The diesel driven fire pumps start circuits also have time delays to prevent simultaneous starting of the fire pumps.
The jockey fire pump operates continuously to keep the system pressurized at or above 100 psig. Water from the jockey fire pump is recirculated back into the service water bay via a minimum flow orifice. A check valve isolates the orifice when a main fire pump operates thus conserving water to fight the fire. Should the jockey pump be removed from service for maintenance, the fire suppression water system header pressure will be maintained through operation of the motor driven fire pump or through a temporary connection to a service water booster pump which takes suction from the non-critical service water header. In the case of a failure of the jockey pump or the temporary connection, the fire suppression water system will be pressurized by automatic operation of the motor driven fire pump by tripping of one or all of the pumps header pressure switches. Operation of the motor driven fire pump is annunciated in the control room to alert the operator of system usage.
The backup supply to the other systems is activated by locally starting a fire pump and hand opening the block valves.
Administrative procedures are used to monitor and control combustible materials when required for use in safety-related areas and throughout the Plant.
DSAR CHAPTER 9 - AUXILIARY SYSTEMS Revision 36 SECTION 9.6 Page 9.6-5 of 9.6-7 9.6.3 DESIGN ANALYSIS The Palisades Fire Safety Analyses are based on physical evaluation of plant systems, structures, components and fire detection and suppression provisions, coupled with plant design and construction documentation. In the analyses, fire areas have been identified and evaluated with respect to the following:
General area description Identification of hazards, including combustible materials and potential ignition sources Overview of the fire protection features and supporting analysis and exemptions Fire barriers defining the area Manual suppression provisions Potential for radiological release Results of risk-informed, performance-based evaluation Achievement of nuclear safety performance criteria Fire areas are areas that are sufficiently bounded to withstand the hazards associated with the area and, as necessary, to protect important equipment within the area from a fire outside the area.
9.6.4 FIRE PROTECTION PROGRAM The fire protection program is based on the NRC requirements and guidelines, Nuclear Electric Insurance Limited (NEIL) Property Loss Prevention Standards and related industry standards. With regard to NRC criteria, the fire protection program meets the requirements of 10 CFR 50.48(f).
A Safety Evaluation was issued on February 27, 2015 by the NRC, that transitioned the existing fire protection program to a risk-informed, performance-based program based on NFPA 805, in accordance with 10 CFR 50.48(f). With respect to the defueled facility, only Chapter 5, and specific NFPA 805 Sections referenced from Chapter 5, are still applicable.
9.6.4.1 Design Basis Summary 9.6.4.1.1 Defense-in-Depth The fire protection program is focused on protecting the safety of the public, the environment, and plant personnel from a plant fire and its potential effect on safe and stable conditions. The fire protection program is based on the concept of defense-in-depth. Defense-in-depth shall be achieved when an adequate balance of each of the following elements is provided:
- 1.
Preventing fires from starting,
DSAR CHAPTER 9 - AUXILIARY SYSTEMS Revision 36 SECTION 9.6 Page 9.6-6 of 9.6-7
- 2.
Rapidly detecting fires and controlling and extinguishing promptly those fires that do occur, thereby limiting fire damage,
- 3.
Providing an adequate level of fire protection for structures, systems, and components important to safety, so that a fire that is not promptly extinguished will not prevent essential plant safety functions from being performed.
9.6.4.1.2 Codes of Record The codes, standards and guidelines used for the design and installation of plant fire protection systems are as follows (Reference 76):
- 1.
NFPA 10-1967, Standard for Portable Fire Extinguishers
- 2.
NFPA 13-1968, Standard for the Installation of Sprinkler Systems
- 3.
NFPA 14-1963, Standard for the Installation of Standpipe and Hose Systems
- 4.
NFPA 15-1962, Standard for Water Spray Fixed Systems for Fire Protection
- 5.
NFPA 20-1966(1972), Standard for the Installation of Stationary Pumps for Fire Protection
- 6.
NFPA 24-1965, Standard for the Installation of Private Fire Service Mains and their Appurtenances.
- 7.
NFPA 72D-1967(1975)(1979), Standard for the Installation, Maintenance and Use of Proprietary Protective Signaling Systems
- 8.
NFPA 72E-1974(1984), Standard on Automatic Fire Detectors
- 9.
NFPA 80-1967, Standard for Fire Doors and Fire Windows
- 10.
NFPA 600-2000, Standard on Industrial Fire Brigades 9.6.4.2
System Description
9.6.4.2.1 Required Systems Fire Protection Systems and Features Chapter 5 of NFPA 805 describes the requirements for fire protection during decommissioning and permanent shutdown which includes the requirements for the site fire brigade and fire fighting support equipment (as referenced to NFPA 805 Chapter 3).
Radioactive Release Structures, systems, and components relied upon to meet the radioactive release criteria are discussed in the, NFPA 805 Fire Protection Program (Reference 43).
DSAR CHAPTER 9 - AUXILIARY SYSTEMS Revision 36 SECTION 9.6 Page 9.6-7 of 9.6-7 9.6.4.2.2 Definition of "Power Block" Structures The terms "Power Block" and "Plant" refer to structures that have equipment required for nuclear plant operations.
9.6.4.3 Fire Protection Program Documentation, Configuration Control and Quality Assurance In accordance with Chapter 5 of NFPA 805, a fire protection plan documented in FPIP-1, "Fire Protection Plan, Organization and Responsibilities," defines the management policy and program direction and defines the responsibilities of those individuals responsible for the plan's implementation. This procedure:
Designates the senior management position with immediate authority and responsibility for the fire protection program.
Designates a position responsible for the daily administration and coordination of the fire protection program and its implementation.
Defines the fire protection interfaces with other organizations and assigns responsibilities for the coordination of activities. In addition, FPIP-1 identifies the various plant positions having the authority for implementing the various areas of the fire protection program.
Identifies the appropriate authority having jurisdiction for the various areas of the fire protection program.
Identifies the procedures established for the implementation of the fire protection program, including the post-transition change process and the fire protection monitoring program.
Identifies the qualifications required for various fire protection program personnel.
Detailed compliance with the programmatic requirements of NFPA 805 are contained in the NFPA 805 Fire Protection Program (Reference 43).
DSAR CHAPTER 9 - AUXILIARY SYSTEMS Revision 36 SECTION 9.7 Page 9.7-1 of 9.7-2 9.7 AUXILIARY FEEDWATER SYSTEM 9.7.1 DESIGN BASIS Following the implementation of Permanently Defueled Technical Specifications, the Auxiliary Feedwater System information herein is considered historical and does not constitute design requirements unless otherwise noted to still be applicable in the defueled condition.
Equipment in the system was historically designed to CP Co Design Class 1 requirements (see Reference 3) with the exception of portions of steam supply piping to P-8B (Figure 9-13).
9.7.2 SYSTEM DESCRIPTION AND OPERATION 9.7.2.1
System Description
The system originally consisted of one electric motor-driven pump (P-8A) and one turbine-driven pump (P-8B) with piping, valves and associated instrumentation and controls. In 1983, a third high-pressure safety injection pump was converted to AFW service as the second electric motor-driven pump (P-8C) in the AFW system. Piping, valves and controls were added to provide redundancy of supply up to the containment penetrations where the redundant systems merge to form just two AFW lines - one to each steam generator (Figure 9-12).
In 1988, flow control bypass valves were added around the flow control valves from P-8C.
The two original pumps are located in a tornado-proof CP Co Design Class 1 portion of the turbine building. Pump C is located in west engineered safeguards room in the auxiliary building.
In 2018, a fourth AFW pump, P-8D, was installed. Pump P-8D is a nonsafety-related, diesel-driven pump. The pump discharge connects to the safety-related AFW pump discharge piping, just outside the containment penetrations. Check valves are installed in the discharge piping.
In addition to the installation of P-8D, a cross-connect between the demineralized water storage tank T-939 and the condensate storage tank T-2 was installed.
9.7.2.2 Component Description Design ratings and construction of components are shown in Table 9-12.
9.7.2.3 Deleted
DSAR CHAPTER 9 - AUXILIARY SYSTEMS Revision 36 SECTION 9.7 Page 9.7-2 of 9.7-2 9.7.3 DELETED 9.7.4 DELETED 9.7.5 DELETED
DSAR CHAPTER 9 - AUXILIARY SYSTEMS Revision 36 SECTION 9.8 Page 9.8-1 of 9.8-18 9.8 HEATING, VENTILATION AND AIR-CONDITIONING SYSTEM Following the implementation of Permanently Defueled Technical Specifications, the HVAC System information herein is considered historical and does not constitute design requirements unless otherwise noted to still be applicable in the defueled condition. Based on revised accident analysis in Chapter 14, no plant HVAC systems are required provided spent fuel has decayed for 17 days and no cask is moved over the SFP less than 90 days after core offload.
9.8.1 DESIGN BASIS
- 1.
The Heating, Ventilation and Air-Conditioning System is designed to provide a suitable environment for equipment and personnel. The path of air for ventilating systems in potentially radioactively contaminated areas runs from areas of low activity toward areas of progressively higher activity for ultimate discharge from the Plant via the ventilation stack. The condensate and makeup demineralizer building HVAC system is also designed so air flows from areas of low potential airborne radioactivity to areas of higher potential airborne radioactivity.
High-efficiency air filters are provided for the exhaust.
- 2.
The design is based upon the ambient conditions listed in Table 9-13.
- 3.
The containment building, radwaste area and fuel handling area are designed for containment of radioactive particles. The exhaust air from these areas is ducted to high-efficiency filters to assure minimum activity levels for the stack discharge and to maintain containment of radioactive particles in those areas of possible contamination. The fuel handling area also has a charcoal filter in parallel with the high-efficiency filter which may be placed in operation during fuel handling operations or heavy load movements.
- 4.
The control room Heating, Ventilation and Air-Conditioning (HVAC)
System was modified in 1983 in response to NUREG-0737, Item III.D.3.4. The design bases for the system are as follows:
- a.
The control room HVAC system maintains a dry bulb temperature as indicated in Table 9-13.
- b.
The control room HVAC system is designed to permit periodic inspection, testing and maintenance of principal components with minimal interruption of normal control room operation.
- c.
The control room HVAC system is designed to remain functional during and after a safe shutdown earthquake.
- d.
The control room HVAC system is designed to remain functional during and after a design basis tornado.
DSAR CHAPTER 9 - AUXILIARY SYSTEMS Revision 36 SECTION 9.8 Page 9.8-2 of 9.8-18 9.8.2 SYSTEM DESCRIPTION AND OPERATION 9.8.2.1
System Description
Plant equipment spaces are ventilated and cooled with ambient outside air.
The outdoor design maximum is 95°F. A space temperature of 110°F is the design limit for personnel occupancy. Indoor and outdoor HVAC design basis ambient conditions are presented in Table 9-13. This table also reveals areas that have maximum indoor temperatures that exceed 110°F. The ventilation systems are either induced draft using motor-driven roof exhausters or forced draft fan and duct distribution systems. Spot cooling of equipment is used where it is impractical to cool the entire space. The HVAC systems are shown in Figure 9-14.
Airflow controllers are used to maintain negative differential pressures in equipment compartments and between controlled and noncontrolled spaces in the auxiliary building and auxiliary building addition. This negative pressure is used to induce infiltration into compartments thus producing a predictable direction of airflow toward areas of increasing radiation hazard. Final exhaust from these potentially contaminable compartments is discharged to atmosphere through the ventilation stack after filtering out radioactive particulate matter in a high-efficiency filter. The fuel handling area exhaust has a charcoal filter in parallel with the high-efficiency filter which is placed in operation during fuel handling operations.
The two auxiliary heating boilers are available for use. Each boiler has the capacity to satisfy heating requirements at the minimum outdoor design temperature of -10°F.
The total control room HVAC system, shown schematically in Figure 9-14, Sheets 5, 6 and 7, consists of two trains of air handling, air filtering units and Continuous Air Monitor (CAM) units (Train A and Train B), the purge exhaust system, toilet exhaust system, and associated ductwork, dampers, instruments and controls.
To reduce noise levels, acoustical diffusers were installed at the HVAC duct outlet supplies to the office and Control Room Supervisor's areas. An acoustical silencer was installed in the main supply duct to the Control Room.
Both modifications provided effective noise reduction in the main Control Room.
A CP Co Design Class 1 mechanical equipment room (MER) (located above the emergency diesels) is provided to house the HVAC equipment. The equipment room is divided into two compartments separated by a 3-hour fire barrier. All components of one train are located in one compartment to meet the redundancy criteria. The MER is part of the control room envelope.
DSAR CHAPTER 9 - AUXILIARY SYSTEMS Revision 36 SECTION 9.8 Page 9.8-3 of 9.8-18 The major components of Train A are an air handling unit (V-95), a condensing unit (VC-11), one Continuous Air Monitor unit (consists of sampling head RE-1818A, display/processing unit RIA-1818A and air pump P-968A), one charcoal filter unit (VF-26A) and associated fan (V-26A).
Dampers associated with Train A are D-1, D-2, D-3, D-4, D-5, D-6, D-7, D-20 and Tornado Dampers TD-1 and TD-4.
The major components of Train B are an air handling unit (V-96), a condensing unit (VC-10), one Continuous Air Monitor unit (consists of sampling head RE-1818B, display/processing unit RIA-1818B and air pump P-968B), a charcoal filter unit (VF-26B) and an associated fan (V-26B).
Dampers associated with Train B are D-8, D-9, D-10, D-11, D-12, D-13, D-14, D-21 and Tornado Dampers TD-2 and TD-5.
The purge exhaust system consists of Fan V-94, Isolation Dampers D-15 and D-16 and Tornado Damper TD-3. Toilet exhaust system Fan V-16 has Isolation Dampers D-17 and D-18 and Tornado Damper TD-6.
DPIC 1659 and 1660 control positive pressure in the control room envelope with respect to the relative pressure of the south hallway outside the control room viewing gallery.
Cooling water for the condensing units and water chiller is Plant service water.
The ventilation and air-conditioning control systems use pneumatic-type controllers with pneumatic-electric switching devices to interconnect the equipment and the controls. Instrument air for the controllers is taken from the Plant instrument air system.
9.8.2.2 Component Description The design data for the major components in the control room HVAC system are listed in Table 9-14.
- 1.
Air Handling Units V-95 and V-96 Each air handling unit consists of a medium efficiency filter, an electric heating coil, a refrigerant cooling coil, a centrifugal fan and associated ductwork, instrumentation and controls. The electric heating coil is not normally utilized since the control room heat load is adequate to maintain air temperature. A steam injection grid is located in the supply ductwork after the airflow measuring unit for each air handling system.
DSAR CHAPTER 9 - AUXILIARY SYSTEMS Revision 36 SECTION 9.8 Page 9.8-4 of 9.8-18
- 2.
Condensing Units VC-10 and VC-11 The water-cooled condensing units supply refrigerant to the cooling coil of Air Handling Units V-95 and V-96, as required. Cooling water to the condensing units is supplied from the Plant service water.
- 3.
Charcoal Filter Units VF-26A and VF-26B Charcoal pressurization/recirculation filter units, each with a 3,200 ft3/min capacity, are provided. Each filter train consists of medium efficiency prefilters, an electric heating coil, upstream high-efficiency particulate air (HEPA) filters, two banks of 2-inch carbon adsorber trays, downstream HEPA filters, a vaneaxial fan, an electric modulating damper and associated ductwork, instrumentation and controls.
- 4.
Humidifiers VH-12 and VH-13 A 50 lb/h capacity humidifier is provided for each air handling unit. The humidifier consists of a steam generator, with high water cutoff and steam dispersion tubes for installation in the ductwork.
- 5.
Bubble-Tight Isolation Dampers Damper D-1 and D-2 are series dampers which provide isolation of the normal air intake on Train A. Dampers D-8 and D-9 are series dampers, of the same design, which provide isolation of the normal air intake on Train B. Dampers D-15 and D-16 are series smoke purge isolation dampers. All of these dampers are leakage class bubble-tight (Reference 24) and are designed to prevent seat leakage at a design operating pressure of 4.0 inches of water. These dampers have air-operated actuators with fail-close features.
- 6.
Continuous Air Monitors A Continuous Air Monitor unit in installed in each Control Room HVAC equipment room. Each CAM unit consists of sampling head RE-1818A (Train A), RE-1818B (Train B), display/processing unit RIA-1818A (Train A) RIA-1818B (Train B) and air pump P-968A (Train A) P-968B (Train B). Each CAM unit is installed with stainless steel tubing sample lines to monitor each outside air intake downstream of the outside air isolation damper and alarm on airborne radioactivity.
9.8.2.3 Codes
- 1.
The work, equipment and materials for the original Plant HVAC system design conform to the requirements and recommendations of the following codes and standards as applicable:
DSAR CHAPTER 9 - AUXILIARY SYSTEMS Revision 36 SECTION 9.8 Page 9.8-5 of 9.8-18
- a.
The work and materials conform to the American Society of Heating, Refrigeration and Air Conditioning Engineers Guide (ASHRAE).
- b.
The fans conform to the Air Moving and Conditioning Association, Inc, standards, definitions, terms and test codes for centrifugal, axial and propeller fans.
- c.
The work, equipment and materials conform to the National Fire Protection Association Pamphlet 90A, "Air Conditioning, Warm Air Heating, Air Cooling Ventilating System."
- 2.
The work, equipment and materials for the control room HVAC modifications made in 1983 conform to the requirements and recommendations of the following additional guides, codes and standards, as applicable:
- a.
Ventilation ductwork conforms to applicable sections of the Sheet Metal and Air Conditioning Contractors National Association (SMACNA) manual.
- b.
Refrigerant cooling coils conform to the standards of the Air Conditioning and Refrigeration Institute (ARI) and to requirements for Seismic Category I equipment.
- c.
Applicable components and controls conform to the requirements of Underwriters Laboratories (UL), the National Electric Manufacturers Association (NEMA) and the Institute of Electrical and Electronics Engineers (IEEE) Standards 323, 344 and 383.
- d.
Charcoal filter units and the associated ductwork, dampers and controls conform to the applicable sections of American National Standard Institute (ANSI) Standard 509-1980 and Standard 510-1980.
- 3.
Control room dampers D-1, D-2, D-8, D-15, and D-16 are bubble-tight dampers that conform to the applicable sections of American Society of Mechanical Engineers (ASME) AG-1, Code on Nuclear Air and Gas Treatment (Reference 24).
9.8.2.4 Operation
- 1.
The HVAC systems are shown in Figure 9-14.
- 2.
The operation of the air handling units for the turbine building is as follows:
DSAR CHAPTER 9 - AUXILIARY SYSTEMS Revision 36 SECTION 9.8 Page 9.8-6 of 9.8-18
- a.
Each unit has one steam coil downstream of a mixing box. The mixing box dampers and steam coil are controlled to provide a 60°F supply air temperature.
- b.
If the fan motor is shut off, the fresh air inlet dampers will close.
- c.
During normal operation, air is supplied to the auxiliary feed pump room by one of the turbine building air handling units and air is exhausted back to the main turbine building space via an exhaust duct located in the ceiling of the auxiliary feed pump room.
- 3.
Steam-operated unit heaters are provided to heat the turbine building and other areas as needed. On all of the unit heaters when heat is required, a thermostat starts the fan automatically.
- 4.
Roof exhausters are provided for the turbine building, feedwater area, intake structure and boiler room. Thermostats set at preset temperatures individually start the roof exhausters so that all roof exhaust fans will be operating at a maximum temperature of 104°F.
- 5.
Wall supply fans in the feedwater area and in the vicinity of the condensate pumps are started at preset temperatures by thermostats mounted in the area.
- 6.
The supply unit mounted on the intake structure will operate continuously supplying a mixture of outside and return air. Wall supply fans are started at preset temperatures by thermostats mounted in the area.
- 7.
The supply units for the diesel generator room supply fresh air as the cooling load requirements demand. These fans are started automatically in sequence by thermostats.
- 8.
Operation of the air supply units for the fuel handling area and the radwaste area is as follows:
- a.
Each air supply unit is equipped with steam coils, a preheat coil and a reheat coil, and an air filter.
- b.
The two steam coils function to maintain supply air temperature appropriate for the area supplied from each fan.
- c.
A thermostat senses the preheat coil leaving air temperature and closes an alarm circuit on low temperature to signal faulty coil performance. The alarm is located in the control room HVAC panel.
- d.
If the fan motor is shut off, the fresh air inlet dampers close.
DSAR CHAPTER 9 - AUXILIARY SYSTEMS Revision 36 SECTION 9.8 Page 9.8-7 of 9.8-18
- 9.
The operation of the auxiliary building office air-conditioning unit is as follows:
- a.
Air is recirculated and mixed with fresh air to provide a mixed air temperature of 60°F.
- b.
The steam coil and chilled water cooling coil in the air-conditioning unit are controlled by a thermostat in the supply fan discharge flow path.
- c.
The supply airflows remain nearly constant but the fresh airflow varies depending upon the setting of the occupancy selector switch and the mixed air thermostat.
- d.
If the fan motor is shut off, the fresh air inlet dampers close.
- 10.
The duct heaters for both the auxiliary building systems and the turbine building offices are controlled by room thermostats to obtain the desired room temperatures.
- 11.
The access control duct cooling coil is controlled by the same thermostat that controls the duct heater.
- 12.
The control room HVAC system operates in two different modes described in Paragraphs a. and b. below. Tornado protection is described in Paragraph c. below:
- a.
Normal Mode During normal mode operation, either Train A or Train B operates to supply air to the control room, Technical Support Center (TSC) and viewing gallery, and maintains a positive pressure with respect to the surroundings.
When Train A is in operation, Air Handling Unit Fan V-95 supplies conditioned air to the control room, TSC and viewing gallery. The room differential pressure controller modulates Damper D-2 to bring in a sufficient amount of outside air to maintain a positive control room pressure. Control room temperature is maintained by two 2-stage thermostats located in the control room, which control Condensing Unit VC-11 by unloading cylinders. Dampers D-1 and D-2 are interlocked with the air handling unit fan to open when the fan is running and to close when the fan is stopped. A humidistat controls the humidity to 40% relative humidity (design basis is 50% relative humidity). Humidifiers are interlocked with a high limit humidistat and with the fan.
DSAR CHAPTER 9 - AUXILIARY SYSTEMS Revision 36 SECTION 9.8 Page 9.8-8 of 9.8-18 The Train A damper positions during normal mode operation are as follows:
(1)
Dampers D-5, D-6 and D-7 close.
(2)
Dampers D-1, D-3, D-4 and D-20 open.
(3)
Damper D-2 modulates.
The Train B damper positions during normal mode operation are as follows:
(1)
Dampers D-12, D-13 and D-14 close.
(2)
Dampers D-8, D-10, D-11 and D-21 open.
(3)
Damper D-9 modulates.
Dampers D-1, D-2 and D-4 isolate Air Handling Unit V-95 of Train A from the outside and Train B when Train A is not in operation.
Dampers D-8, D-9 and D-11 isolate Air Handling Unit V-96 of Train B from the outside and Train A when Train B is not in operation.
When Train B operates, Air Handling Unit V-96 supplies conditioned air to the control room, TSC and viewing gallery.
The room differential pressure controller modulates Damper D-9 to bring in a sufficient amount of outside air to maintain positive pressure in the control room. Control room temperature is maintained by two 2-stage thermostats located in the control room, which control Condensing Unit VC-10 by unloading cylinders. Dampers D-8 and D-9 are interlocked with the air handling unit fan to open when the fan is running and to close when the fan is stopped. A humidistat controls the humidity to 40% relative humidity (design basis is 50% relative humidity).
Humidifiers are interlocked with a high limit humidistat and with the fan. A smoke detector is provided for each train (E/U-351 -
Train A, E/U-352 - Train B) in the normal fresh air intake to the Air Handling Unit. The smoke detectors are located between the tornado damper and the outside air dampers and is used to provide the operator with indication that smoke is being drawn into the Control Room from the fresh air intakes.
- b.
Purge Mode Smoke can be purged from the control room by Fan V-94. This fan is manually started by the operator, when required. When
DSAR CHAPTER 9 - AUXILIARY SYSTEMS Revision 36 SECTION 9.8 Page 9.8-9 of 9.8-18 the purge fan is started (with V-95 running), Dampers D-15 and D-16 open; Return Damper D-3 closes; and Dampers D-1 and D-2 open fully to bring in 9,060 ft3/min outside air and prevent recirculation. When the purge fan is started (with V-96 running),
Dampers D-15 and D-16 open; Damper D-10 closes; and Dampers D-8 and D-9 open. Purge Fan V-94 exhausts 7,800 ft3/min to the atmosphere, 160 ft3/min is exhausted by the toilet exhaust fan and 1,100 ft3/min exfiltrates.
When the purge fan runs in conjunction with Train A, the damper positions are as follows:
(1)
Damper D-3 closes.
(2)
Dampers D-1, D-2, D-15 and D-16 open.
When the purge fan runs in conjunction with Train B, the damper positions are as follows:
(1)
Damper D-10 closes.
(2)
Dampers D-8, D-9, D-15 and D-16 open.
- c.
Tornado Protection Tornado dampers are provided in all the outside air intakes, the purge exhaust and the toilet exhaust ducts. During tornado depressurization, the tornado dampers close to isolate the HVAC system from the outside.
- d.
Control Room/TSC Envelope Four vestibules are used to provide egress and ingress to the control room/TSC. These vestibules are adjacent to Doors 108, 115, 175 and 52. Their function is to prevent air in-leakage.
- e.
Penetrations to the Control Room Envelope Uncontrolled open penetrations to the control room/TSC envelope degrades the maintenance of positive air pressure.
Therefore, administrative controls are used for maintenance activities requiring an open penetration. These controls assure prompt and secure closure of openings in the event of an emergency.
Other electronic equipment used in plant safety-related components can operate at 120°F continuously and at 140°F intermittently as proven by experience.
DSAR CHAPTER 9 - AUXILIARY SYSTEMS Revision 36 SECTION 9.8 Page 9.8-10 of 9.8-18 Cooling of safety-related equipment and controls located in rooms other than the main control room is maintained by systems designed with similar component redundancy as the control room air-conditioning system.
- 13.
Each engineered safeguards equipment room has one cooler with two fans, one powered from Class 1E MCC-1 and the other powered from Class 1E MCC-2.
- 14.
Two iodine removal filter units are installed in containment. The units are freestanding and do not use inlet or outlet ductwork.
- 15.
The containment purge and vent system is operated as follows:
- a.
One main exhaust fan (V-6A or V-6B) must be running.
- b.
Purge isolation valves (CV-1805 and CV-1806, and/or CV-1807 and CV-1808) are opened.
- c.
Air room supply isolation valves (CV-1813 and CV-1814) are opened and air room purge supply fan (V-46) is started. During cold weather heat is supplied by Heating Coil VHX-48.
- d.
The purge system is stopped by reversing the above procedure.
- 16.
The radwaste area exhaust system operates as follows:
- a.
Normally both fans, each rated at 50% of the normal flow, operate continuously. Dampers in the fan discharge modulate to maintain a uniform static pressure in the filter intake plenum.
- b.
The filter intake pressure is the static pressure of a balanced airflow from all areas with access openings closed or in the normal condition. The ductwork is sized to permit airflows from the cells through access ports sufficient to permit entrainment velocities. Thus, if an access port or hatch cover is open, the air velocity through the opening is over 100 feet per minute and the fan discharge dampers will open to maintain the set static pressure at the filter intake plenum.
- c.
Hoods have high-efficiency particulate filters as an integral part of the hood, and booster fans are provided to offset the pressure drop through the filter.
DSAR CHAPTER 9 - AUXILIARY SYSTEMS Revision 36 SECTION 9.8 Page 9.8-11 of 9.8-18
- d.
In the event of an exhaust fan failure, the supply fan may be shut down and the negative pressure of the radwaste area will be maintained by the remaining exhaust fan.
- e.
In the event of failure of the radwaste area supply fan, one of the exhaust fans is automatically shut down but the pressure control apparatus will limit the amount of the negative pressure developed by the lack of supply air and prevent excessive pressure differentials.
- f.
In the event of a spillage of radioactive material in the radwaste area, the radiation monitor at the filter plenum senses the activity and stops the supply fan, closes the radwaste area supply Damper PO-1809, and stops the selected exhaust fan; however, a low flow alarm will override the high radiation signal and keep the standby exhaust fan running. The duct to access control remains open and is isolated from the radwaste area by Damper PO-1809.
- 17.
The fuel handling area exhaust system operates as follows:
- a.
During normal operation, one or both of the exhaust fans run, as required, and draw air through a prefilter and a high-efficiency filter.
- b.
During fuel handling operations, the exhaust air may be diverted through a prefilter, HEPA filter and a charcoal adsorber bed.
This filter train is parallel to the normal high-efficiency filters and is isolated from it by the positioning of an inlet damper.
- c.
In the event of a fuel handling/cask (heavy load) drop accident in the spent fuel pool, the exhaust airflow is reduced to one-half by tripping the supply fan and closing the inlet damper and tripping one of the 50% capacity exhaust fans. The exhaust air flows through the high-efficiency particulate filter and a charcoal filter. No credit is taken for Fuel Handling Building HVAC in the Chapter 14 safety analysis.
- 18.
The operation of the auxiliary building addition fuel handling supply and radwaste supply is as follows:
- a.
The supply unit for each area is equipped with a preheat coil, a reheat coil and an automatic filter.
- b.
The preheat coil is controlled by a thermostat in the fresh air intake set at 35°F. The reheat coil is controlled by a leaving air thermostat to maintain a discharge temperature of 60°F.
DSAR CHAPTER 9 - AUXILIARY SYSTEMS Revision 36 SECTION 9.8 Page 9.8-12 of 9.8-18
- c.
Another thermostat is provided in the leaving air stream which is set at 45°F and alarms in the control room when this temperature is reached to indicate faulty coil performance.
- d.
If the fan motor is shut off, the fresh air inlet dampers close.
- e.
The supply fans will trip on a high-radiation signal from radiation monitors located in the corresponding exhaust system ducts.
- 19.
The operation of the auxiliary building addition fuel handling area exhaust and radwaste exhaust systems is as follows:
- a.
The exhaust systems each consist of a filter package which contains a bank of roughing filters and a bank of HEPA filters.
Air is drawn through the filter plenum by two exhaust fans.
- b.
Normally both fans, each rated at 50% of the normal flow, operate continuously. Dampers in the fan discharges modulate to maintain a uniform static pressure in the filter intake plenum.
- c.
In the event of an exhaust fan failure, the supply fan may be shut down and the negative pressure of the area served by the particular system will be maintained by the remaining exhaust fan.
- d.
In the event of failure of a supply fan, one of the exhaust fans will shut down but the pressure controller in the filter intake plenum will limit the amount of negative pressure developed by the lack of supply air and prevent excessive pressure differentials.
- e.
In the event of release of radioactive material in the area served by the system, the radiation monitor at the filter plenum senses the activity and trips the supply fan which in turn trips one of the exhaust fans. However, a low flow condition will override the high-radiation signal and keep the standby exhaust fan running.
- f.
In the event of a radioactive release in the fuel handling area, Operations takes manual actions to secure the auxiliary building addition fuel handling area supply and exhaust. Additionally, administrative actions are in place to close the equipment hatch and the personnel airlock within a specified time. Further, other area boundary doors are controlled or maintained closed during fuel handling operations.
- 20.
The penetration and fan rooms' heating and ventilating system provides cooling air to the feedwater pipe penetration room and fan room. The system operates as follows:
DSAR CHAPTER 9 - AUXILIARY SYSTEMS Revision 36 SECTION 9.8 Page 9.8-13 of 9.8-18
- a.
The supply system consists of a supply fan, an air filter and an outside air damper.
- b.
The exhaust system consists of a prefilter, a high-efficiency filter and an exhaust fan.
- c.
The supply and exhaust systems run concurrently and are controlled by a thermostat located in the exhaust duct. The supply and exhaust fans are started when the exhaust air temperature is 90°F and stop when the exhaust air temperature is 70°F.
- d.
A differential pressure controller which measures differential pressure across the filters and filter inlet damper, modulates the filter inlet damper to maintain a preset negative pressure across the filters and dampers.
- 21.
The electrical equipment, switchgear, cable spreading and battery rooms' HVAC system was modified in the 1983 outage to include the new electrical equipment room added as part of the control room modification work. This system formerly served the viewing gallery.
This system operates as described below and serves the following areas:
Electrical Equipment Room Cable Spreading Room Bus 1D Switchgear Room Bus 1C Switchgear Room Battery Room The ventilation system that services these areas is composed of V-33 and V-43 with supplemental ventilation supplied by V-47, none of which are safety grade. Supply Fan V-33 provides 18,500 scfm of air to the areas identified. Makeup air to V-33 is a blend of outside air and recirculated air from V-43. This blend is controlled by a mixed air temperature controller. When outside air temperature increases, the amount of recirculation is decreased, and the amount of makeup increases up to the full 18,500 scfm.
The Cable Spreading Room is equipped with a duct mounted type smoke detector E/U-238E. It is located in the duct downstream of recirculating fan V-43 and damper CD-19. Its function is only to provide an indication to the operator that smoke is being drawn from the Cable Spreading Room.
The duct branch that services the new electrical equipment room is equipped with a chilled water cooling coil to provide adequate cooling for the room. This cooling coil is controlled by a thermostat located in the electrical equipment room.
DSAR CHAPTER 9 - AUXILIARY SYSTEMS Revision 36 SECTION 9.8 Page 9.8-14 of 9.8-18 Separate from this two-fan ventilation system is a 30,000 scfm exhaust fan that takes suction on the cable spreading, Bus 1D switchgear and Bus 1C switchgear rooms only. When air temperature in the upper region of the rooms increases above 100°F, Temperature Switches 1824, 1825 and 1826 will initiate a control room annunciator none of which are safety grade. The operator may manually start the supplemental Exhaust Fan V-47. Normally, the temperature will drop below the 100°F set point within 10 minutes and the operator will stop V-47.
If the high-temperature alarm does not clear, other corrective measures available to the operator would be: check fan and damper operation, ensure heating steam controller and cooling controllers are functioning, ensure filter media is clear, block open doors, place fire protection smoke blowers in rooms as temporary air movers.
- 22.
The containment building air coolers operate as follows:
The service water supply line for each safety-related cooler has an air-operated stop valve which is electrically locked open. The return line for each safety-related cooler has an 8" air-operated discharge valve which is usually (in cold weather) held closed and a 4" temperature control valve in a bypass line around the closed discharge valve. The normal operating position of the service water discharge valve for VHX-3 is open to preclude the potential for silt/sand buildup on the closed valve disc which may cause valve binding (Reference EAR-2002-0027). The non-safety related cooler (VHX-4) has air-operated valve in its service water supply and return lines that are normally open. The VHX-4 return line valve can be closed during cold weather to reduce the cooling occurring in containment. The 4" temperature control valves were modified by SC-93-054 to eliminate the automatic temperature control function. These valves may be manually operated locally using the provided air regulator but are typically kept full open (with the exception of VHX-4's TCV, whose air supply has been isolated per FC-713, failing it closed). Because the temperature control function was eliminated, the valve equipment IDs are now CV rather than TCV. The supply and 8" discharge valves may be manually operated from the main control room and the engineered safeguards local panel. The bypass valves can only be closed from the control room by isolating instrument air to containment.
Air is drawn through the containment air coolers by two matched vaneaxial fans with direct connected motors. One fan motor is rated for normal conditions and the second is rated for high capacity conditions. During normal operation the total airflow through each cooler is 60,000 CFM. All fans may be manually started or stopped from the main control room or at the individual breakers.
DSAR CHAPTER 9 - AUXILIARY SYSTEMS Revision 36 SECTION 9.8 Page 9.8-15 of 9.8-18
- 23.
The CRDM cooling system consists of two fans.
- 24.
The containment post-accident filter system is described in Section 6.5.
- 25.
The main steam line and feedwater line containment penetration cooling system consists of two fans.
- 26.
Operation of the condensate and makeup demineralizer building HVAC system is as follows:
- a.
The heating and ventilation air handling units perform the ventilation and heating function for the condensate and makeup demineralizer building areas. The systems are designed to take outside air, mix it with return air as applicable, filter it at the air handling unit and distribute it to the building areas. Areas being served by the heating and ventilating air handling units are provided with thermostats for control of winter space temperatures. Exhaust airflows are from areas of low potential airborne radioactivity to areas of higher potential airborne radioactivity.
- b.
The instrument room air-conditioning unit provides cooling and heating for the instrument room. The system is designed to take outside air, mix it with return air, filter it, and deliver it to the instrument room. A space thermostat is provided for heating temperature control. The system is equipped for economizer control for room cooling.
- c.
The boiler room supply fan and roof exhauster perform the ventilating function for the boiler room. The equipment supplies outside air and exhausts hotter room air. The fans are started and stopped by room thermostats or may be operated manually by a control switch.
- d.
The air compressor and switchgear room and the pipe gallery use wall louvers and roof ventilators for ventilation. The systems are started and stopped by room thermostats or may be operated manually with control switches.
- e.
Unit heaters are controlled individually by room thermostats.
DSAR CHAPTER 9 - AUXILIARY SYSTEMS Revision 36 SECTION 9.8 Page 9.8-16 of 9.8-18
- 27.
Operation of the Volume Reduction and Solidification (VRS) area HVAC systems are as follows:
- a.
The VRS area control room air-conditioning unit provides cooling for the VRS area control room. The system is designed to take room return air, mix it with minimum outside air, filter and cool the air as necessary and deliver it to the VRS system control room. The air-conditioning unit is controlled from a room thermostat. Redundant condensers are provided for the air-conditioning unit for reliability.
- b.
The VRS area supply air system consists of an air-conditioning unit with an air-cooled condenser. Outside air is drawn through the unit, filtered and cooled as necessary and delivered to the space. A space thermostat controls operation of the unit.
- c.
The VRS area exhaust system consists of a duct system which is tied into the existing radwaste area exhaust system. The air supplied to VRS area is drawn through the space and exhausted to the outside through the radwaste area exhaust filter (VF-73).
- 28.
The shed for auxiliary feedwater pump P-8D has a ventilation system and redundant area heaters, with automatic and manual control capabilities.
9.8.3 TESTS AND INSPECTIONS Provisions for testing equipment performance are built into the critical apparatus such as exhaust systems, the engineered safeguards room coolers and the control room air-conditioning unit and refrigerant condensers. After the equipment is installed and operating, periodic tests may be performed to assure that filters and coils are not dirty or plugged and the unit is still performing as required.
9.8.4 LOSS OF INSTRUMENT AIR TO VENTILATION DAMPERS Table 9-15 lists the ventilation dampers, their function, and positions during operation of the Plant under normal and abnormal conditions and loss of instrument air. Particular attention has been given to the failed position of dampers to ensure maximum safety of Plant personnel and minimum emission of possible contaminants to the environment.
DSAR CHAPTER 9 - AUXILIARY SYSTEMS Revision 36 SECTION 9.8 Page 9.8-17 of 9.8-18 The control room HVAC system damper positions for the various modes of operation are discussed in Subsection 9.8.2.4, Item 12.
The normal radwaste area ventilation mode is with all dampers open, Supply Fan V-10 running, one or both exhaust fans (V-14A and/or V-14B) running, and the exhaust dampers (PO-1839 and PO-1840) controlled by filter intake pressure to maintain balanced airflow from all areas. A high-activity level at the filter intake plenum will actuate the radiation monitor (RE-1809) which will close the radwaste area supply damper (PO-1809), trip one exhaust fan (V-14A or B) if both are running, close the respective exhaust damper, and trip the supply fan (V-10) which will in turn close the supply damper. The remaining exhaust fan will maintain a slight negative pressure on the radwaste area to prevent leakage out of the building. The tripped exhaust fan will restart if 2.5 inches of water vacuum is not maintained in the exhaust plenum.
The normal ventilation mode in the fuel handling area is Supply Damper PO-3007 open, Supply Fan V-7 operating, one or both exhaust fans (V-8A or V-8B) operating, and one or both gravity exhaust dampers open. Upon a fuel building high-radiation area alarm, Fan V-7 is manually tripped which closes Damper PO-3007 and one exhaust fan is manually tripped closing its gravity damper. The remaining running fan continues to run maintaining a slight negative pressure on the fuel building to prevent leakage from the building.
Upon loss of instrument air, Supply Damper PO-3007 will shut. The supply fan and one exhaust fan will be manually tripped to ensure no building leakage in the unlikely event a simultaneous release of activity occurs within the fuel building.
9.8.5 SAFETY EVALUATION 9.8.5.1 Deleted 9.8.5.2 Evaluation
- 1.
Control Room Heating, Ventilation and Air Conditioning (CRHVAC)
System The function of the CRHVAC system is to provide a controlled environment for the comfort and safety of control room personnel.
This system was modified during the 1983 outage in response to NUREG-0737, Item III.D.3.4 concerns. The system is described in Subsection 9.8.2.
Safety Analysis for dose consequences are presented in Chapter 14 for various accident conditions.
DSAR CHAPTER 9 - AUXILIARY SYSTEMS Revision 36 SECTION 9.8 Page 9.8-18 of 9.8-18
- 2.
Spent Fuel Pool Area Ventilation System The function of the spent fuel pool area ventilation system is to maintain ventilation in the spent fuel pool equipment areas, to permit personnel access, and to control airborne radioactivity in the area during normal operation and following postulated fuel handling accidents.
Based on the fuel handling accident analysis in Section 14.19, it was determined that the system is nonessential.
- 3.
Radwaste Area Ventilation System The radwaste area ventilation system services most areas within the auxiliary building, including the engineered safeguard equipment rooms (east and west), the charging pump room, the primary drain tank pump room and the boric acid control area.
If loss of instrument air were to occur, the Supply Damper PO-3010 A, B, C and D, radwaste area Supply Damper PO-1809, the two Exhaust Dampers PO-1839 and PO-1840 would fail closed. In addition, if offsite power is lost, the radwaste area ventilation system would fail.
- 4.
Electrical Equipment, Switchgear and Cable Spreading Rooms Ventilation System The areas served and operation of this system are discussed in Subsection 9.8.2.
- 5.
Intake Structure Ventilation System The intake structure ventilation system is addressed in this evaluation because it services the area where the three service water pumps are located. The system consists of seven supply fans, five wall-mounted units (V-21D-H) and two roof units (V-32A and B). These supply fans draw atmospheric air into the building. The air is then exhausted back outside through five roof-mounted exhaust fans (V-30A-E).
The intake structure ventilation system was originally sized to cool circulating water pumps in addition to the service water pumps. The existing ventilation system is now oversized for normal operation since the circulating water pumps have been removed.
DSAR CHAPTER 9 - AUXILIARY SYSTEMS Revision 36 SECTION 9.9 Page 9.9-1 of 9.9-1 9.9 SAMPLING SYSTEM 9.9.1 DESIGN BASIS The sampling systems are designed to permit liquid and gaseous sampling for analysis.
9.9.2 SYSTEM DESCRIPTION AND OPERATION The sampling system is a collection of smaller subsystems which are designed to sample various Plant fluids. These subsystems are designated by the Plant systems or fluid sampled. Table 9-16 lists each subsystem.
Block and bleed valves are located on the reactor coolant and LPSI pump suction sample lines.
The containment hydrogen monitoring system (Figure 9-16) consists of redundant monitors. Each monitor contains a sample pump, temperature, pressure and flow controllers, and a thermal conductivity cell.
The Turbine Plant Analyzer Station is located in the turbine building. This station contains sample pressure reducing and cooling equipment including valves, pressure regulators, pressure indicators, flow regulators, piping grab sample sinks and continuous analyzers. A data acquisition system, indicators and an annunciator are located at the Turbine Plant Analyzer Station.
The Radwaste Sample Station (Figure 9-17), located in the auxiliary building sample room, provides sample streams for grab sampling or collection in sample bombs. The sample streams are radioactive or potentially radioactive fluids.
The Radwaste Addition Sample Station, located in the new radwaste building sample room, provides sample streams for grab sampling or collection in sample bombs. The sample streams are radioactive or potentially radioactive fluids.
Table 9-17 is a summary of sample points.
9.9.3 SYSTEM EVALUATION The sampling system obtains a maximum of information from a number of separately located sample points and stations. All of the continuous sample analysis equipment is located near its sample conditioning equipment which permits rapid detection of deteriorating conditions of either the samples or the sampling equipment.
DSAR CHAPTER 9 - AUXILIARY SYSTEMS Revision 36 SECTION 9.10 Page 9.10-1 of 9.10-7 9.10 CHEMICAL AND VOLUME CONTROL SYSTEM Following the implementation of Permanently Defueled Technical Specifications, the Chemical and Volume Control System information herein is considered historical and does not constitute design requirements unless otherwise noted to still be applicable in the defueled condition.
9.10.1 DESIGN BASIS The Chemical and Volume Control System (CVC) is a CP Co Design Class 3 system.
The design parameters for the Chemical and Volume Control System and components are listed in Table 9-18.
The portions of the system utilized for Primary Coolant System isolation and for Containment isolation were CPCo Class 1.
9.10.2 SYSTEM DESCRIPTION AND OPERATION 9.10.2.1 General The Chemical and Volume Control System is shown in Figure 9-18.
The volume control tank is designed and sized with a large enough capacity that with the level in the normal control band, the tank can accommodate a zero to full power increase or a full to zero power decrease.
9.10.2.2 Volume Control The CVC automatically adjusts the volume of water in the Primary Coolant System using a signal from the level instrumentation located on the pressurizer.
The volume control tank can store enough coolant below its normal operating level to compensate for a full to zero power decrease in the primary coolant volume without requiring makeup. The tank is supplied with hydrogen and nitrogen gas. Gases may be vented to the waste gas surge tank.
9.10.2.3 Chemical Control The CVC purifies and conditions the primary coolant by means of ion exchangers, filters and chemical additives.
The purification demineralizers contain a mixed bed resin. A demineralizer post-filter is located downstream of the purification demineralizers.
The chemical control system is designed to prevent the activity of the primary coolant from exceeding approximately 292 Ci/cc with failed fuel elements.
DSAR CHAPTER 9 - AUXILIARY SYSTEMS Revision 36 SECTION 9.10 Page 9.10-2 of 9.10-7 9.10.2.4 Deleted 9.10.2.5 Deleted 9.10.2.6 Component Functional Description The major components of the Chemical and Volume Control System perform the following functions:
- 1.
Regenerative Heat Exchanger The regenerative heat exchanger transfers heat from the letdown stream to the charging stream. Materials of construction are primarily austenitic stainless steel.
- 2.
Letdown Heat Exchanger The letdown heat exchanger cools the letdown stream from the tube side of the regenerative heat exchanger to a temperature suitable for entry into the purification demineralizer. Component Cooling System fluid is the cooling medium on the shell side of the letdown heat exchanger, with the letdown stream passing through the tube side.
Materials of construction are primarily austenitic stainless steel.
- 3.
Purification Demineralizers The two purification demineralizers provide a means of removing undesired ionic species such as activation/fission products and lithium from the primary coolant system. They are configured in one of two ways:
- 1)
One vessel is loaded with mixed bed resin in the borate/lithium form and the other vessel loaded with cation only resin in the hydrogen form. The borate/lithium demineralizer is used during normal operation to remove ionic specie without removing lithium. The cation demineralizer is placed in service periodically to remove the natural build in of PCS lithium.
- 2)
One vessel is loaded with mixed bed resin in the borate/lithium form and the other vessel loaded with mixed bed resin in the borate/hydrogen form. In this configuration the borate/lithium form demineralizer is used during normal operation to remove ionic specie without removing lithium. The borate/hydrogen form demineralizer is placed in service periodically to remove the natural build in of PCS lithium. During PCS source term evolutions the borate/hydrogen form demineralizer is placed in service.
DSAR CHAPTER 9 - AUXILIARY SYSTEMS Revision 36 SECTION 9.10 Page 9.10-3 of 9.10-7 Each unit is designed to handle maximum letdown flow of 120 gpm.
The vessels and retention screens are constructed of austenitic stainless steel.
- 4.
Deborating Demineralizer The deborating demineralizer may be used to remove boron from the primary coolant when this mode of operation is preferable to a feed and bleed operation, or may be used as a purification demineralizer.
The anion resin used for deborating is initially in the hydroxyl form and is converted to a borated form during boron removal. The unit is designed for the maximum letdown flow of 120 gpm, and the quantity of resin is sufficient to remove the equivalent of 50 ppm of boron from the entire Primary Coolant System. The vessel and retention screens are of austenitic stainless steel construction.
- 5.
Purification Filters The purification filters collect resin fines and insoluble particulates from the primary coolant. The filters will accommodate maximum letdown flow of 120 gpm. The filter housing is austenitic stainless steel.
- 6.
Volume Control Tank The volume control tank accumulates water from the Primary Coolant System. The tank has enough capacity to accommodate the variation in water inventory of the Primary Coolant System due to power level changes in excess of that accommodated by the pressurizer. The tank provides a gas space where hydrogen atmosphere is maintained to control the hydrogen concentration in the primary coolant. A vent to waste processing system permits removal of gaseous fission products released from solution in the volume control tank. The tank is of austenitic stainless steel construction and provided with overpressure protection. Level controls release coolant to the waste processing system on high level or notify the operator of the need to supply makeup water.
DSAR CHAPTER 9 - AUXILIARY SYSTEMS Revision 36 SECTION 9.10 Page 9.10-4 of 9.10-7
- 7.
Charging Pumps Three charging pumps supply makeup water to the Primary Coolant System. The pumps return coolant to the Primary Coolant System at a rate equal to the purification flow rate and the bleedoff rate. The charging pumps automatically start upon a safety injection signal and discharge concentrated boric acid into the Primary Coolant System.
P-55B and P-55C automatically start upon low pressurizer level. The pumps are of the positive displacement type. All wetted parts, except seals, are of austenitic stainless steel. Two of the pumps are fixed capacity pumps while one (P-55A) is a variable capacity pump. Any two of the three pumps are capable of providing an output of 68 gpm, with a single pump providing a minimum of 33 gpm. The normal purification flow rate is specified in Table 9-18. Accumulators are located on the suction and discharge of each pump to reduce pump induced vibrations.
- 8.
Chemical Addition Tank The chemical addition tank is used to prepare chemicals for primary coolant pH control, oxygen control, and source term reduction evolutions. These chemicals are added to the suction of the charging pumps with the metering pump. The tank is austenitic stainless steel.
- 9.
Metering Pump The metering pump is an air operated double diaphragm pump with wetted parts of austenitic stainless steel. The pump is used to inject a controlled amount of chemicals into the suction of the charging pumps.
- 10.
Concentrated Boric Acid Storage Tanks Each of the two concentrated boric acid tanks stores enough concentrated boric acid solution to bring the reactor to a cold shutdown condition at any time during the core lifetime. The combined capacity of the tanks will also be sufficient to bring the primary coolant to refueling concentration. The tanks are heated to maintain a temperature above the saturation temperature of the concentrated solution, and sampling connections are used to verify that proper concentration is maintained. The tanks are constructed of stainless steel.
DSAR CHAPTER 9 - AUXILIARY SYSTEMS Revision 36 SECTION 9.10 Page 9.10-5 of 9.10-7
- 11.
Boric Acid Pumps The two boric acid pumps supply boric acid solution at the desired concentration to the charging pumps through the blender. Upon a safety injection signal, these pumps line up with the charging pumps to permit direct introduction of concentrated boric acid into the Primary Coolant System. Each is capable of supplying boric acid at the maximum demand conditions. Each pump is capable of providing a minimum flow of 68 gpm. Wetted parts of the pumps are stainless steel.
- 12.
Process Radiation Monitor The process radiation monitor monitors the fluid from the primary coolant loop for high levels of activity which would provide an indication of failed fuel.
9.10.3 SECTION DELETED 9.10.4 DESIGN ANALYSIS System Reliability The CVC is designed for reliability by the provision of redundant components.
Redundancy is provided as follows:
Component Redundancy Purification Demineralizer Parallel Standby Unit Purification Filters Parallel Standby Unit Charging Pump Two Parallel Standby Units Letdown Flow Control Two Parallel Standby Orifices and Valves Boric Acid Pump and Tank Parallel Standby Unit The boric acid solution is stored in heated tanks and piped in heat-traced lines to preclude precipitation of the boric acid. Two independent heating systems are provided for the boric acid tanks and lines. Low temperature alarms and automatic temperature controls are included in the heating systems. If the boric acid pumps are not available, boric acid from the concentrated boric acid tanks may be gravity fed into the charging line. If the charging line inside the reactor containment building is inoperative, the charging pump discharge may be routed via the Safety Injection System to inject concentrated boric acid into the Primary Coolant System.
9.10.5 DELETED
DSAR CHAPTER 9 - AUXILIARY SYSTEMS Revision 36 SECTION 9.10 Page 9.10-6 of 9.10-7 9.10.6 REGENERATIVE HEAT EXCHANGER The Regenerative Heat Exchanger (RHX) was CP Co Design Class 1 and was designed according to the ASME Boiler and Pressure Vessel Code,Section III, Class C (ASME B&PV Code,Section III, Class C) vessel. There are two principal reasons for this:
- 1.
A reliable charging path was the principal reason for originally considering Class A for this component. As the detailed design of the Palisades Plant evolved, it was found desirable to add a two-inch, high-pressure line from the charging pumps through one of the high-pressure safety injection headers and to the primary loop through the four safety injection headers. Thus, an alternate charging path was available. Also, it was felt desirable to have the ability to isolate the RHX by remote manual means. Therefore, isolation valves are located on the inlet and outlet lines of both the shell and tube sides of the RHX as shown on Figure 9-18. These valves can be operated from the control room.
- 2.
The manufacturer of the Palisades RHX was unable to obtain approval from the ASME Code "N" stamp committee to produce ASME B&PV Code,Section III, Class A components. Combustion Engineering (CE) knew of no manufacturer of such heat exchangers who had met the requirements of the "N" stamp committee. CE and the vendor agreed to additional quality control inspections, to be provided by CE, as detailed in subsequent paragraphs.
Combustion Engineering assured that the following requirements were met, which were in addition to those required for a Class C vessel, and which would normally have been performed for a Class A vessel.
- 1.
A fatigue analysis equivalent to the requirements of a Class A vessel was performed by the manufacturer or his consultant. This analysis was reviewed under the direction of a licensed professional engineer at CE to assure its accuracy.
- 2.
The Quality Control requirements of ASME B&PV Code,Section III, Appendix IX, 1965, W67a were met except that shop inspection personnel, although experienced in inspection techniques, did not meet in all respects the qualifications of the applicable standards.
Inspections were performed in accordance with written procedures which had been reviewed by CE Quality Assurance (QA) personnel. In addition, CE QA personnel witnessed certain predetermined inspections and also conducted random periodic surveillance inspections. Inspection records were kept at the manufacturer's office and also at Combustion Engineering. Certification of inspection compliance was transmitted to Consumers Power Company.
DSAR CHAPTER 9 - AUXILIARY SYSTEMS Revision 36 SECTION 9.10 Page 9.10-7 of 9.10-7 In addition to the above, nondestructive testing was witnessed by CE QA personnel who were qualified to ASME B&PV Code,Section III, Appendix IX, 1965, W67a procedures. All nondestructive test procedures were reviewed by CE QA personnel and were deemed acceptable and in accordance with ASME B&PV Code,Section III, Appendix IX, 1965, W67a.
With the aforementioned changes in Plant design, additional analyses and quality control, we believe that Class C vessel classification of the regenerative heat exchanger was justified.
During operations the RHX primary side shell to tube-sheet welds and the primary head are periodically inspected per ASME Code requirements.
DSAR CHAPTER 9 - AUXILIARY SYSTEMS Revision 36 SECTION 9.11 Page 9.11-1 of 9.11-28 9.11 FUEL HANDLING AND STORAGE SYSTEMS 9.
11.1 INTRODUCTION
The Fuel Handling System (Table 9-19) provides for the safe handling and storage of fuel under all foreseeable conditions, including shipment of irradiated fuel following radioactive decay. The design and construction of the system includes interlocks, travel and load limiting devices and other protective measures to minimize the possibility of mishandling or equipment malfunction that could cause damage to the fuel and potential fission product release. Power operation of the system components is supplemented by manual backup to ensure that the fuel handling activities can be completed in the event of a power failure. The fuel transfer and storage structures, the fuel handling equipment and the new fuel storage racks are CP Co Design Class
- 1. The high density spent fuel storage racks which replaced the existing racks and the frame supporting the fuel pool crane are Seismic Category I per USNRC Regulatory Guide 1.29.
9.11.2 NEW FUEL STORAGE The new fuel rack is a box-like structure consisting of 72 locations, 36 of which can hold new fuel. The other locations contain steel box beams and core plugs designed for neutron absorption in the event of a heavy mist over the pool such as that produced in fire fighting. The fuel racks can accommodate fuel assemblies having a maximum planar average U-235 enrichment of:
- a.
4.05 weight percent assuming the staggered loading pattern shown in Figure 4.3-1 of Technical Specifications, which allows storage of thirty-six assemblies, or
- b.
4.95 weight percent assuming the staggered loading pattern shown in Figure 4.3-1 of Technical Specifications, which allows storage of twenty-four assemblies.
The fuel racks are also used occasionally to store core plugs, poison clusters and spare control elements.
DSAR CHAPTER 9 - AUXILIARY SYSTEMS Revision 36 SECTION 9.11 Page 9.11-2 of 9.11-28 9.11.3 SPENT FUEL STORAGE 9.11.3.1 Original Design The spent fuel storage pool, located in the auxiliary building adjacent to the containment, is lined with stainless steel and has reinforced concrete walls and floor varying in thickness from 4-1/2 feet to 6 feet.
The original fuel racks were stainless steel with a center-to-center spacing of 11-1/4 inches. There were two 1/4-inch stainless steel plates between each pair of fuel assemblies. At design temperature, with no credit taken for soluble boron in the pool water, the maximum keff was less than 0.95. A recessed area was provided in the pool for a spent fuel shipping cask.
The spent fuel pool cooling system is conservatively designed to maintain a pool average temperature at less than 150°F with 1/3 core of fully burned up fuel in the pool, 7 days after reactor shutdown. A single failure of the cooling system would increase the pool temperature by only 3°F. The water in the spent fuel pool is borated to t 1,720 ppm. The spent fuel pool cooling system is tornado protected and is located in a CPCo Design Class 1 structure, except as noted in Section 9.4.3.1.
Makeup sources include the Primary System Makeup Storage Tank (T-90),
Service Water System, and Fire Protection System The makeup source can be unborated water, but the amount added is controlled to prevent the pool from going below 1720 ppm.
Two fuel tilt pits are located in the fuel handling area adjacent to the spent fuel pool and connected to it by canals which are closed off by dam blocks.
One tilt pit was used for normal fuel transfer activities. The second tilt pit originally was provided to accommodate an additional unit on the site, and is now utilized for spent fuel storage.
DSAR CHAPTER 9 - AUXILIARY SYSTEMS Revision 36 SECTION 9.11 Page 9.11-3 of 9.11-28 9.11.3.2 Modified Spent Fuel Storage In 1977, due to the lack of fuel reprocessing facilities, the spent fuel pool storage capacity was increased from a capacity of 272 assemblies to a capacity of 798 assemblies. This increase in capacity was achieved by removing the existing fuel and control rod racks and replacing them with new racks with smaller center-to-center spacing.
Each individual storage location consists of two concentric 1/8-inch austenitic Type 304 stainless steel square cans with the annular space occupied by B4C neutron absorber plates to ensure subcriticality.
A rack assembly consists of a rectangular array of storage cans with a minimum 10-1/4 inches center-to-center spacing of the fuel assemblies. The array size of each rack was chosen to optimize the use of the pool space as shown in Figure 9-20. The racks are Seismic Category I per NRC Regulatory Guide 1.29 and are restrained to the pool wall at the top and bottom of each rack to prevent excessive movement of the racks under postulated seismic accelerations. Provisions are made in the design to accommodate thermal expansion.
The second tilt pit is used for spent fuel and control rod storage and as an alternate cask laydown area. Control rods and dimensionally abnormal fuel assemblies may be stored in one rack with slightly larger cans than those used in the other racks. To minimize heat generation in the tilt pit, normally only fuel decayed for at least one year will be stored there. When fuel with a shorter decay time is stored in the tilt pit, thermal conditions are monitored to ensure that the design criteria is not exceeded.
The Nuclear Waste Policy Act of 1982 required owners of nuclear power plants to diligently pursue licensed alternatives to the use of federal storage capacity for the storage of the spent fuel expected to be generated by that plant before entering into a contract with the Federal Government to provide such storage.
A second modification to the spent fuel storage facility, in 1987, consisted of an increase of the spent fuel pool total storage capacity from 798 assemblies to 892 (see Reference 5). This increase in capacity was accomplished by removing 376 storage locations having a 10.25-inch center-to-center spacing, and replacing them with 470 storage locations having a 9.17-inch center-to-center spacing. The 9.17-inch center-to-center spacing has been accomplished by taking credit for burnup with poison. In addition, the new storage locations have more space in each location, and permit 2:1 consolidation if this method is chosen in the future to further expand storage capacity.
This second (1987) modification consisted of reracking approximately one-half of the spent fuel pool and North Tilt Pit dividing the spent fuel pool
DSAR CHAPTER 9 - AUXILIARY SYSTEMS Revision 36 SECTION 9.11 Page 9.11-4 of 9.11-28 and North Tilt Pit into two regions, which are designated as Region 1 and Region 2 (see Figure 9-20). The reason only approximately one-half of the spent fuel pool was reracked was due to the need to maintain a portion of the storage capacity with larger center-to-center spacing to accommodate the storage of fuel with little or no burnup. The racks (Region 1), with 10.25 center-to-center spacing, have the required spacing to store such fuel.
The third (2013) modification to the spent fuel storage facility removed the Region 1 racks containing Carborundum from the main Spent Fuel Pool (not the North Tilt Pit) and replaced them with Region 1 racks that contain Metamic'. Metamic' is a patented boron carbide and aluminum metal matrix composite material that is manufactured by Holtec International and fabricated to the criteria of 10 CFR 50, Appendix B. Metamic' is a metal matrix composite manufactured from nuclear grade boron carbide powder and aluminum powder. The Metamic' used in the Metamic' monitoring program using representative material coupons placed in the Spent Fuel Pool is implemented to confirm the continued integrity of the Metamic'. The Metamic' racks have the same number of storage cells per rack as the previous Main Pool Region 1 Carborundum racks and therefore this modification did not change the total storage capacity of the Spent Fuel Pool.
Region 1 of the Main Pool contains racks having a 10.25 inch center-to-center spacing. The Region 1 Main Pool racks contain a neutron absorbing material, The Metamic' used in the Main Pool Region 1 racks contains a minimum B10 areal density of 0.02944 gm/cm2.
Region 1 of the North Tilt Pit contains a single rack having 11.25-inch x 10.69-inch center-to-center spacing. The Region 1 North Tilt Pit rack contains a neutron absorbing material, Carborundum', manufactured by the Carborundum Company and fabricated to the criteria of 10 CFR 50, Appendix B. Carborundum' is a mixture of boron carbide powder and phenol formaldehyde resin in a homogeneous matrix. The Carborundum' used in the Region 1 North Tilt Pit rack contains a nominal and minimum B10 areal density of 0.0959 and 0.0863 gm/cm2, respectively. Since the long term stability of Carborundum' neutron absorber plates has not yet been resolved, the Region 1 North Tilt Pit criticality calculations were revised to eliminate any credit taken for criticality control due to the presence of B10 in Carborundum'.
Region 2 contains racks in both the spent fuel pool and the north tilt pit having 9.17-inch center-to-center spacing. The Region 2 racks contain a neutron absorbing material, Boraflex, manufactured by the Brand Industrial Services, Inc, and fabricated to the Nuclear Criteria of 10 CFR 50, Appendix B.
Boraflex is a silicone-based polymer containing fine particles of boron carbide in a homogeneous matrix. The Boraflex used in the Region 2 racks contains a minimum B10 areal density of 0.006 gm/cm2. Since the long-term stability of Boraflex has not yet been resolved, the Region 2 criticality calculations were
DSAR CHAPTER 9 - AUXILIARY SYSTEMS Revision 36 SECTION 9.11 Page 9.11-5 of 9.11-28 revised to eliminate any credit taken for criticality control due to the presence of Boraflex.
Each Region 2 rack module is provided with adjustable leveling pads which are located at selected locations within the module. The pads are remotely adjustable from above. All support pads rest directly on the pool liner and/or adapter plates.
The cask laydown area in Region 2 may contain one 11 x 11 rack which may be used to store fuel during full core off-loads. This rack may be removed to allow placement of the spent fuel shipping cask, to allow placement of equipment associated with dry fuel storage, or to allow the use of fuel inspection and repair equipment.
The spent fuel pool also contains non-fuel irradiated components such as control rods and incore instruments.
9.11.3.3 Structural Analysis The spent fuel storage racks are designated Seismic Category I per NRC Regulatory Guide 1.29. Structural integrity of these racks was investigated using the loads and load combinations presented in Reference 1, which satisfy the requirements of NRC Standard Review Plan (SRP), Section 3.8.4.
Stresses were computed at critical sections of the rack. A comparison of the computed versus allowable stresses indicates that the racks are structurally adequate. A discussion of this analysis, with emphasis on the seismic aspects, is found in Subsection 5.7.6.
The fuel pit and tilt pit floors and walls were analyzed to determine if they could support the fully loaded, high-density, spent fuel racks. A conservative analysis was performed for dead (fully loaded racks, hydrostatic), seismic (inertia of floors/walls, rack reactions, sloshing) and thermal loads. Forces and moments obtained at selected points were combined in accordance with the load combinations presented in Subsection 5.9.1.1.2. The maximum tensile/compressive stress was computed for each load combination and compared with the required yield strength of the structure ("Y"). For the seven walls and two floors analyzed, the minimum factor of safety was found to be 1.1 and the average factor of safety was found to be 4.5. Therefore, it was concluded that the fuel pit and tilt pit floors and walls have adequate strength to safely support the increased fuel storage.
The spent fuel pool structure was designed for ductile behavior (ie, with reinforcing steel stresses controlling the design). The acceptance criteria were stated in Chapter 5, Appendix A of the 1980 FSAR. These criteria were applied in the 1979 structural reanalysis. Acceptance is based on maintaining structural integrity and ductile behavior of the pool structure.
DSAR CHAPTER 9 - AUXILIARY SYSTEMS Revision 36 SECTION 9.11 Page 9.11-6 of 9.11-28 The fuel racks (Region 2) were analyzed for normal and faulted load combinations in accordance with the NRC "OT Position for Review and Acceptance of Spent Fuel Storage and Handling Applications." The results of this seismic and structural analysis show that the Region 2 racks meet all structural acceptance criteria adequately.
An analysis was performed to demonstrate that the Region 2 rack can withstand a maximum uplift load of 4,000 pounds. This load can be applied to a postulated stuck fuel assembly without violating the criticality acceptance criterion. Resulting stresses are within acceptable stress limits, and there are no changes in rack geometry of a magnitude which cause the criticality acceptance criterion to be violated.
The unlikely event of dropping a fuel assembly has also been addressed.
Both the Region 1 and Region 2 racks are designed to absorb the impact of a dropped assembly without experiencing significant deformation. In the unlikely event that a fuel assembly is dropped onto one of the racks the assembly would end up sitting on the top of the racks separated from the active fuel column of the assemblies in the storage rack by greater than 10 inches of borated water. This separation is adequate to preclude neutron interaction. Therefore, the reactivity increases due to the dropped assembly scenario for the Region 1 and Region 2 racks is bounded by the misloaded assembly accident.
Consistent with the criteria of the NRC "OT Position for Review and Acceptance of Spent Fuel Storage and Handling Applications," the racks were evaluated for overturning and sliding displacement due to earthquake conditions under the various conditions of full, partially filled, and empty fuel assembly loadings. The fuel rack nonlinear time history analysis shows that the fuel rack slides a minimal distance. This distance combined with the rack structural deflection and thermal growth is less than rack-to-rack or rack-to-wall clearances at all locations, except at the interface between the Region 1 Metamic' (Main Pool) and Region 2 racks. At this interface, the Region 1 Metamic' rack baseplates extend beyond the perimeter envelope of the cell region in order to protect the rack cellular structure from impact during a seismic event and maintain the installed inter-rack spacing. Therefore, by design the racks are predisposed to impact each other at the baseplate level during a seismic event, rather than at the top of rack elevation. The impact stress on the rack baseplates is well below the Level A bearing stress limit per ASME Subsection NF. The factor of safety against overturning is well within the values permitted by Section 3.8.5.11.5 of the Standard Review Plan.
9.11.3.4 Prevention of Criticality During Storage The Region 1 Carborundum racks in the North Tilt Pit are designed with B4C plates around each assembly. Borated water surrounds the racks in the same concentration and to a level common to the refueling cavity and pool. As
DSAR CHAPTER 9 - AUXILIARY SYSTEMS Revision 36 SECTION 9.11 Page 9.11-7 of 9.11-28 discussed earlier, the most recent criticality analysis for Region 1 Carborundum racks did not take credit for B10 in the Carborundum. The elimination of B10 in Carborundum from the calculation is offset by crediting the soluble boron in the Spent Fuel Pool water, selective loading of the fuel interspersed with empty cells, and restricting the assembly planar average enrichment.
The Region 1 Metamic' racks in the main pool are designed with Metamic' as a neutron poison. Borated water surrounds the racks in the same concentration and to a level common to the refueling cavity and pool. The most recent criticality calculation for the Region 1 Metamic' racks takes credit for B10 in Metamic'.
The Region 2 racks are designed for a 9.17 inch center-to-center spacing with Boraflex sheets used as a neutron absorbing material to compensate for the closer spacing. As discussed earlier the most recent criticality calculation for Region 2 did not take credit for Boraflex. The omission of Boraflex from the calculation is compensated for by taking credit for the presence of soluble boron in the spent fuel pool water and the radioactive decay time of the spent fuel being stored.
The precedent of crediting soluble boron to provide criticality control aside from normal reactor operations has already been established. Soluble boron credit was used in the Westinghouse Spent Fuel Rack Criticality Analysis Methodology described in WCAP-14416-NP-A. That methodology was accepted for use by an NRC Safety Evaluation dated October 25, 1996.
Additional guidance outlining the requirements for use of soluble boron has been issued by the NRC and documented in Guidance on the Regulatory Requirements for Criticality Analysis of Fuel Storage at Light-Water Reactor Power Plants, Laurence I. Kopp, U.S. Nuclear Regulatory Commission, Office of Nuclear Reactor Regulation, Reactor Systems Branch, February 1998.
The Region 1 and 2 criticality calculations take credit for soluble boron in the Spent Fuel Pool. Region 1 Carborundum (North Tilt Pit) and Region 2 criticality calculations define a storage configuration but do not take credit for the solid B10 in the racks. Region 1 Metamic' (Main Pool) criticality calculations do take credit for solid B10 in the Metamic' material. The soluble boron credit is used to offset the various uncertainties related to the criticality calculation. The uncertainties included are for reactivity equivalencing methodology, manufacturing tolerances, and off-normal conditions that include stuck assemblies, rack deformation and complete voiding of water outside of the fuel assembly envelope in Region 1. Crediting soluble boron provides subcritical margin such that the Spent Fuel Pool keff is maintained less than or equal to 0.95.
The Region 1 Metamic' (Main Pool) criticality calculation demonstrates that keff is less than 1.0 for the maximum enrichment with no restrictions on loading
DSAR CHAPTER 9 - AUXILIARY SYSTEMS Revision 36 SECTION 9.11 Page 9.11-8 of 9.11-28 patterns. The Region 1 Carborundum (North Tilt Pit) criticality calculation demonstrates that keff is less than 1.0 for the combination of maximum nominal planar average U-235 enrichment, burnup and restricted loading patterns defined in Section 4.3.1.1, and as augmented by Table 3.7.16-4 and Table 3.7.16-5 of the Technical Specifications, with no credit for solid boron in the racks. Similarly, the Region 2 calculation shows that keff is less than 1.0 for the combinations of maximum nominal planar average U-235 enrichment, burnup and decay time shown in Table 3.7.16-1 of the Technical Specifications with no credit for solid boron in the racks. The presence of 850 ppm of soluble boron ensures that the 95/95 keff is less than or equal to 0.95 under normal storage conditions. Considering that the Technical Specifications require the normal fuel pool boron concentration to be at least 1720 ppm, an 870 ppm margin to the 0.95 limit is inherently present for the soluble deboration event.
The results of the criticality analyses are based on worst case situations, considering fuel assemblies with the maximum fuel enrichment and minimum neutron absorber loading for Region 1 Metamic' (Main Pool) and the maximum variations in the position of fuel assemblies within the Region 1 Carborundum (North Tilt Pit) and Region 2 storage racks. It also considered variations in can dimensions, the most reactive temperature, calculation uncertainties, and worst case accidents for all racks. The results show that the 95/95 keff is less than or equal to 0.95 for Region 1 and for Region 2 with credit for 850 ppm and 1350 ppm of soluble boron in the fuel pool water for the deboration event and the fuel misload event, respectively (References 45 and 75).
In order to maintain a k-effective less than or equal to 0.95 for the tilt machine and fuel elevator, 850 ppm boron is required. This is maintained by meeting normal requirements outlined in Technical Specification LCO 3.7.15 and associated procedures. Credit is taken for boron to maintain k-effective less than or equal to 0.95 with a margin of 870 ppm being available due to the Technical Specification requirement of 1720 ppm.
The criticality analysis performed to support crediting soluble boron in the spent fuel pool (SFP) determined that a minimum boron concentration of 850 ppm would provide a k-effective of less than or equal to 0.95. In order to ensure that the design-basis k-effective of 0.95 is not exceeded due to potential dilution events, a boron dilution analysis to support this criticality analysis was also performed (Reference 10). As a result, it was established that a boron concentration of greater than or equal to 1720 ppm provides adequate margin for fuel assembly storage and movement within the SFP.
Based on the creditable dilution events evaluated, the 1 1/2 inch fire hose station is the only system with practically an infinite water storage source (Lake Michigan) that could provide the necessary volume of water needed to dilute the SFP to 850 ppm. However, with this fire hose, it would take over 9 hours1.041667e-4 days <br />0.0025 hours <br />1.488095e-5 weeks <br />3.4245e-6 months <br /> to dilute the SFP soluble boron concentration from 1720 ppm to
DSAR CHAPTER 9 - AUXILIARY SYSTEMS Revision 36 SECTION 9.11 Page 9.11-9 of 9.11-28 850 ppm. Thus, if an SFP dilution were to occur from this system, reasonable assurance exists that is would be identified and suppressed by an operator before the 0.95 k-effective limit is reached. As an additional measure, a fuel pool high level alarm was added to give an earlier warning of fuel pool increases which could lead to dilution of the soluble boron concentration.
The dilution analysis concluded that an unplanned or inadvertent event that would dilute the SFP is not credible for Palisades. Sufficient time is available to detect and suppress the worst dilution event that can occur from the minimum TS boron concentration to the boron concentration required to maintain the 0.95 k-effective design-basis limit.
Palisades has chosen to comply with 50.68 (b) for criticality accident requirements.
DSAR CHAPTER 9 - AUXILIARY SYSTEMS Revision 36 SECTION 9.11 Page 9.11-10 of 9.11-28 9.11.3.5 Radiological Considerations 9.11.3.5.1 Radiation Shielding Personnel performing fuel inspection activities are protected from excessive radiation levels by water shielding. Fuel assemblies are maintained under at least 10 feet of water, and individual fuel rods are maintained under at least 8 feet of water. The new fuel elevator is designed and operated such that it is not possible to lift irradiated fuel above 10 submergence limit. This is accomplished with limit switches, a key lock and a control system (joystick and operator action). The keys are administratively controlled such that they will not be issued when irradiated fuel is stored in the new fuel elevator.
Mechanical stops are provided for the remaining fuel handling equipment in order to ensure the minimum water shield thickness limits are not violated.
The water level limits serve to maintain the low level of radiation required for unrestricted occupancy. Checklists require proper water level to be verified prior to moving fuel. In addition, annunciation is provided to warn operators of low water level.
9.11.3.5.2 Pool Surface Dose The additional spent fuel assemblies in the pool will result in an increase in dose rates in the spent fuel pool area due to a buildup of radionuclides in the pool water. To determine the amount of increase, a calculational model was devised that considered the presence of activated corrosion products, leakage of the isotopes from the fuel to the pool, the decontamination factor and flow rate of the pool purification system, the isotopic half-lives and the decay time of the fuel. Using this model, the pool's activity was predicted for the original pool capacity (272 assemblies) and for the increased capacity (798 original rerack assemblies). On the refueling platform, 5 feet above the center of the pool, the dose rate increased from 2.17 mrem/h for 272 assemblies to 3.24 mrem/h for 798 assemblies. (At poolside, 1 foot from the pool wall and 5 feet above the surface, the dose rate increased from 1.58 mrem/h to 2.34 mrem/h.) The increase in the pool capacity has a negligible effect on personnel exposure. Assuming an occupancy time of 504 man-hours per year at the refueling platform and 1,134 man-year poolside for refueling operations, and an additional 52 man-hours per year poolside for routine operations, the total incremental dose due to the expansion of pool capacity from 272 to 798 assemblies is 1.43 manrem per year.
DSAR CHAPTER 9 - AUXILIARY SYSTEMS Revision 36 SECTION 9.11 Page 9.11-11 of 9.11-28 The dose rate directly above the spent fuel pool has been measured during routine area surveys on the service platform. Survey sheets were examined for the periods of time between 1975 and 1983 when the Plant was operating.
Thirteen surveys contained dose rate measurements which were taken directly above the spent fuel pool. These measurements ranged from 0.2 to 3.5 millirem per hour. The average dose rate was 1.5 millirem per hour.
Thermoluminescent Dosimeters (TLDs) have monitored dose adjacent (west wall) to the spent fuel pool since the beginning of plant operations. TLD results since the 1996 Refout are 0.16 millirem per hour, 0.35 millirem per hour, and 0.27 millirem per hour for the 1st, 2nd and 3rd quarters of 1997, respectively. Neither the direct surveys nor the full time dose monitoring indicate any correlation between the dose rates and the number of fuel bundles in the spent fuel pool.
9.11.3.5.3 Airborne Doses The water evaporation rate, and hence tritium release to the environment around the spent fuel pool, is expected to change as a result of the following factors:
- 1.
Lower calculated water temperatures for the DSAR in the spent fuel pool than those evaluated previously in the 1980 FSAR.
- 2.
Higher water temperatures in the north tilt pit area relative to the main pool.
- 3.
Increased water surface area due to utilization of the north tilt pit.
Calculations show that the overall evaporation rate will increase approximately 9%.
Airborne samples are taken in the spent fuel pool area and analyzed for tritium. Results are typically less than 0.3 DAC (see 10CFR20 for DAC definition), but may vary somewhat. As with other parameters examined, no correlation could be established between the airborne sample results and the number of fuel bundles in the spent fuel pool.
DSAR CHAPTER 9 - AUXILIARY SYSTEMS Revision 36 SECTION 9.11 Page 9.11-12 of 9.11-28 9.11.3.5.4 General Area Doses The adequacy of the spent fuel pool and tilt pit shielding was analyzed with the QAD and ANISN computer codes, to take into account storage of additional spent fuel.
Analyses have shown that the existing shielding is generally adequate to reduce effectively neutron and secondary gamma radiation in all expected areas of occupancy surrounding the pool. However, three areas in which fission product gamma dose rates have exceeded the DSAR radiation zoning criteria (Section 11.6) have been identified. These are (1) outside the north wall of the north tilt pit, (2) outside the north wall of the existing spent fuel pool, and (3) in the space directly below the spent fuel pool cask loading area.
When the north tilt pit is used to store fuel which has decayed for at least one year, it has been calculated that the expected gamma dose rate on the north wall of the tilt pit, which is 2 feet thick, will be approximately 14 rem/h.
Studies show that approximately 7 inches of lead equivalent will be required in addition to the 2-foot-thick concrete wall to achieve dose rates consistent with the DSAR radiation zoning criteria. Assuming that the spent fuel pool will be used to store fuel which has decayed for at least 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br />, it has been calculated that the expected gamma dose rate on the north wall of the pool will exceed 10 mrem/h. Assuming the cask loading area will be used to store fuel which has decayed for at least 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br />, it has been calculated that the gamma dose rate under the pool floor adjacent to the cask loading area will exceed 200 mrem/h.
9.11.3.5.5 Protection Against Radioactivity Release Protection against accidental radiation release from irradiated fuel is provided by the containment ventilation system and isolation capability, if required, of the spent fuel pit and auxiliary building ventilation system. Because of the submergence of a bundle in 10 feet of water and an individual rod in 8 feet of water, any released fission products will be diluted and partially retained by the pool water.
The ventilation air for both the containment and spent fuel pool atmospheres flows through absolute particulate filters before discharging to the Plant stack.
The containment is normally isolated with purge air only when access to the air room is desired. In the event that the stack discharge should indicate a release in excess of the limits in the Offsite Dose Calculation Manual, an alarm is received in the control room and the ventilation flow path from containment is closed manually from the control room. The ventilation flow paths from the fuel handling area and radwaste area are also manually closed from the control room.
During normal operation, the spent fuel pool area exhaust air is pulled through a prefilter and a high-efficiency filter with a particulate efficiency of
DSAR CHAPTER 9 - AUXILIARY SYSTEMS Revision 36 SECTION 9.11 Page 9.11-13 of 9.11-28 99.97% of 0.3 micron particles. The fuel building exhaust fans discharge to the main exhaust fan inlet plenum for ultimate discharge through the ventilation stack.
In the event of a fuel handling / cask (heavy load) drop accident in the spent fuel pool, the exhaust airflow is reduced to one-half by tripping the supply fan and closing the inlet damper and tripping one of the 50% capacity exhaust fans. The exhaust air flows through the high-efficiency particulate filter and a charcoal filter. See Sections 14.11 and 14.19 for specific assumptions of the Fuel Handling Building HVAC used in the safety analysis.
The radiological filter is in a bypass around the normal service filters and designed for a capacity of 10,000 ft3/min and will retain 1,200 grams of methyl iodide. Its particulate efficiency is 99.0% for particles of 0.3 micron in size, and the filter medium has a test-proven efficiency for removal of radioactive iodine and iodine compounds as follows:
Radioactive Iodine I2131 99.0%
Radioactive Methyl Iodide CH3I2131 94.0%
9.11.4 FUEL HANDLING SYSTEM 9.11.4.1 General Fuel assemblies is accomplished handled underwater at all times. The spent fuel pool is filled with borated water to a common level during fuel handling.
The use of borated water provides a transparent radiation shield, a cooling medium and a neutron absorber to prevent inadvertent criticality.
The service platform is used to remove the fuel from the storage rack and deposit it in the shipping cask for shipment off the site or to deposit it in the Multi-Assembly Storage Basket (MSB) or Multi-Purpose Canister (MPC) for storage at the Independent Spent Fuel Storage Installation. During all handling operations, a sufficient water shield is maintained over the top of the fuel bundle to restrict radiation exposure to operating personnel. The water boron concentration is checked periodically to assure adequate shutdown margins. Water boron concentration is also checked prior to and during MSB or MPC fuel loading.
The new fuel storage area is provided with vertical racks to hold 36 replacement bundles. Reference DSAR Chapter 1 Figures 1-4, 1-8 and 1-10 for plant layouts related to fuel handling equipment.
The new fuel elevator contains an inspection position to allow examination of irradiated fuel. Fuel repairs can be conducted in the elevator.
DSAR CHAPTER 9 - AUXILIARY SYSTEMS Revision 36 SECTION 9.11 Page 9.11-14 of 9.11-28 9.11.4.2 Fuel Handling Structures The refueling cavity is a reinforced concrete structure lined with stainless steel that forms a pool above the reactor.
9.11.4.3 Major Fuel Handling Equipment
- 1.
Reactor Vessel Head Lifting Device The head lifting device is composed of a removable spreader bar assembly and a three-part column assembly and the rigging necessary to lift and move the head to the storage area. The column assembly which remains attached to the head also provides a working platform for personnel during maintenance, and supports the three hoists which are provided for handling the hydraulic stud tensioners, the studs, washers and nuts.
- 2.
Upper Guide Structure Lifting Device When installed, this device allows the main crane to lift the upper guide structure. Three bolts are threaded into the flange of the upper guide structure using a manually operated tool. Bushings on the lifting device engage the guide studs installed on the reactor vessel flange to provide guidance during removal and insertion of the guide structure.
Work platforms are provided for operating personnel and brackets are attached to the lifting device for the storage of withdrawn incore instrumentation.
- 3.
Refueling Machine The refueling machine is a traveling bridge and trolley which spans the refueling cavity. The controls for the refueling machine are mounted on a console which is located on the refueling machine trolley.
- 4.
Tilting Machines Two tilting machines are provided, one in the containment building and the other in the fuel building. The tilting machine installed in the containment building consists of a fabricated hollow rectangular structure, supported through a pivot to a triangular-shaped support base. This structure is closed at one end and open at the other.
The tilting machine installed in the fuel storage area is essentially as described above except that the box structure is open at both ends
DSAR CHAPTER 9 - AUXILIARY SYSTEMS Revision 36 SECTION 9.11 Page 9.11-15 of 9.11-28
- 5.
Transfer Carriage A transfer carriage is provided within the transfer tube that connects the refueling cavity and the spent fuel pool storage area. Two main structural members form the sides of the carrier.
- 6.
Fuel Building Crane In 2003, Facility Change FC-976 modified the main hoist of the Fuel Building Crane to increase the capacity of 110-tons, and to meet single failure criteria in accordance with NUREG-0612, Control of Heavy Loads at Nuclear Power Plants, and NUREG-0554, Single-Failure-Proof Cranes for Nuclear Power Plants. The Fuel Building Crane, L-3, is an indoor electric overhead traveling bridge, single trolley crane, with a radio controlled operator unit. Table 9-20 describes specifics of the Fuel Building Crane. On June 16, 2004, the NRC issued Amendment 215 to the Palisades Operating Licensee No DPR-20 to approve the use of the Fuel Building Crane as a single-failure-proof crane for below-the-hook loads up to 110 tons.
The Fuel Building Crane main hoist is used to handle spent fuel casks.
The spent fuel casks are described in Sections 9.11.5 and 14.11. Prior to the upgrade of the Fuel Building Crane to single failure criteria, movement of Pacific Sierra Nuclear VSC-24 system casks was performed under site-specific heavy load requirements that conform to the recommended guidelines of NUREG-0612 and Generic Letter 85-11. The Fuel Building Crane may be operated in a non-single failure proof manner following site-specific heavy load requirements. Non-single failure proof modes of operation typically involve trolley and bridge speed increases and multiple direction movement control, and are only used when single failure proof operation is not required. Section 14.11 describes postulated cask drop accidents.
The 15-ton auxiliary hoist of the Fuel Building Crane is not single failure proof. Postulated load drops from the auxiliary hoist have been evaluated in accordance with NUREG-0612 and are bounded by the cask drop accidents in Chapter 14.11.
When the main hoist of the Fuel Building Crane is used for single failure proof lifts or lifts in excess of 100-tons, the Auxiliary Building steel frame structure over the Spent Fuel Pool is only qualified for a maximum wind velocity of 90 mi/hr as noted in DSAR Section 5.3.1.2 and Amendment 215.
DSAR CHAPTER 9 - AUXILIARY SYSTEMS Revision 36 SECTION 9.11 Page 9.11-16 of 9.11-28 Codes and Standards The crane was designed, constructed and erected in accordance with the requirements of:
- a.
Crane Manufacturing Association of America Specification #70 -
Class A
- b.
American Welding Society Standard Specifications
- c.
National Electric Manufacturers Association
- d.
American Standards Association
- e.
National Electrical Code
- f.
National Fire Protection Association
- g.
ASME B30.2 - Overhead and Gantry Cranes Factors of Safety The following minimum factors of safety, under static full rated load stresses and based on ultimate strength of material were provided:
Material Factor of Safety Cast Iron 12 Cast Steel 8
Structural Steel 5
Forged Steel 5
Cables 5
Weld 5
(Based on ultimate strength of metal in weld)
Stainless Steel 5
Note: Non-redundant parts of the lifting system (eg, the main hook) have a safety factor of 10.
DSAR CHAPTER 9 - AUXILIARY SYSTEMS Revision 36 SECTION 9.11 Page 9.11-17 of 9.11-28 Explicitly, the factors of safety are:
- a.
For hooks, shear blocks, bridge and trolley drives, complete hoisting mechanism, trolley frames and structural steel parts, not including bridge girders, not less than 5 for the auxiliary hoist and not less than 10 for the main hoist and lower block.
- b.
Bridge girders - Within the allowable stress requirements of NUREG-0554 and AISC.
- c.
Welds - Within the allowable stress requirements of NUREG-0554 and AISC.
- d.
Rope - Not less than 5 for the auxiliary hoist and 7 for the main hoist.
Mechanical Stress Analysis In addition to the usual design requirements given in the referenced codes, the equipment is designed to meet seismic requirements as stated below.
The stresses resulting from the following seismic loads combined with normal operating stresses in no case exceed the yield point of the component materials. The seismic load was calculated as 60% of the dead load applied in any horizontal direction and 15% of the dead load applied in either direction vertically. The criteria is only applied to the unloaded crane.
Positive means are provided to prevent the crane bridge, trolley or any other items normally held by gravity from becoming dislodged and falling on equipment or structures situated below the crane.
Brakes The main hoist is equipped with a mechanical holding brake with a minimum torque rating of 125% of the full load hoisting torque at the point of application. An emergency band brake on the main hoist drum is designed with a minimum capacity of 125% of that required to hold the design rated load. The main and auxiliary hoists are controlled by a Flux Vector Drive systems which control the motor such that lowering and hoisting speeds can be maintained at low speeds for extended periods of time. The Flux Vector Drive is equipped with a dynamic brake which diverts excess current during lowering of the hoist with a load on the hook.
The auxiliary hoist is equipped with a mechanical brake with a minimum torque rating of 125% of the full load hoisting torque.
DSAR CHAPTER 9 - AUXILIARY SYSTEMS Revision 36 SECTION 9.11 Page 9.11-18 of 9.11-28 The bridge and trolley are provided with braking resistors for normal control breaking. The brakes have torque capabilities to stop motion within 10% of rated load speed when traveling at rated speed with rated loads. Parking brakes are provided but are only actuated once the trolley or bridge comes to a complete stop or during emergency breaking.
All brakes are equally effective in both directions.
Two Blocking Two blocking occurs when block and tackle meet.
Two blocking of main hoist could result, with full-rated load on hook, if both upper limit switches fail while hoist control is in the hoist position.
Failure of both upper limit switches is not considered to be credible.
An energy absorbing torque limiter within the main hoist reducer assembly will further protect the hoist system by limiting the load on the hoisting system.
The main hoist motor is rated at 25 hp, 900 r/min, with 3-step control in either direction. The main hoist holding brake will not prevent two blocking of the hoist under rated load conditions.
Two blocking of auxiliary hoist could result with full-rated load on hook, if upper limit switch fails while hoist control is in the hoist position.
The auxiliary hoist motor is rated at 25 hp, 900 r/min, with stepless control in either direction. The auxiliary hoist holding brake will not prevent two blocking of the hoist under rated load conditions.
Hoist Drive System For the 110-ton hoist, the hoist drive is driven by a 1,020:1 ratio gearbox.
Hoisting machinery consists of a continuous duty, telemotive drive, Class H insulation Marathon motor which drives through necessary gear reductions to a winding drum. Gears in reduction units are mounted on short shafts and supported between bearings. The drum gear is pressed on and keyed to the winding drum. The hoist motor is coupled to the speed reducer.
The hoist drum is mounted on pedestal bearings supported on a trolley truck assembly.
The hoist drive motor and gearbox are attached to the trolley truck.
DSAR CHAPTER 9 - AUXILIARY SYSTEMS Revision 36 SECTION 9.11 Page 9.11-19 of 9.11-28 An essentially identical arrangement exists for the 15-ton auxiliary hoist drive system.
Limit Switches The main hoist has control circuit screw-type upper and lower limit switches and a redundant block-operated, paddle-type upper limit switch. These limit switches serve to interrupt current to the motor when the hoist block reaches or exceeds a predetermined limit of travel, thus setting brakes. The former limit switch is reset automatically by moving controller to opposite direction. The latter limit switch is reset using the key bypass switch.
The auxiliary hoist has control circuit upper and lower limit switches capable of setting its brake.
Automatic reset-type limit switches of the forked lever type have been provided to limit travel of bridge on each end of the frame runway. The limit switch is reset by reversal of bridge direction of travel.
An equivalent arrangement to that discussed for the bridge has been provided to limit trolley travel at each end.
Finally, limit switches have been provided to prevent traversal of the fuel pool. Under fuel transfer cask handling operations, the limit switches may be bypassed by a key kept under strict administrative control to allow placing cask in loading area of pool.
Controls Control of all crane functions is from a radio controlled station carried by the crane operator.
The radio controlled station weighs about 7 pounds and has a master key lock power (on-off) switch with additional key lock switches for fuel pool and cask laydown overrides.
The radio control station is housed in a NEMA I enclosure with four-dead man style, spring-return, detent rotary switches for speed control. The master main (on-off) switch is a heavy duty, toggle-type with a mechanical latch required for the on position.
DSAR CHAPTER 9 - AUXILIARY SYSTEMS Revision 36 SECTION 9.11 Page 9.11-20 of 9.11-28 The bridge and trolley drive controllers are three speed, full magnetic with protection, furnished with NEMA I steel enclosures, NEMA Class 162 unbreakable resistors, general duty master switches, and are mounted on the crane for ease of maintenance and convenience.
They are standard GE Type IC 7427A reversing-plugging controllers.
Movement of master switch to first point closes the correct directional contactor to place all starting resistance in the circuit. Accelerating points are controlled by automatic relays which cut out resistance until full speed is attained. Quick reversal of master switch results in immediate reversal of directional contactors but acceleration contactors are held open by plugging relay until motor has stopped and reversed. Some braking is accomplished by plugging motor; however, controlled stopping is accomplished through holding brakes.
The main and auxiliary hoist drive controls are Flux Vector Drive computer controllers mounted in an existing NEMA 1 enclosure.
Electrical The electrical systems furnished are 3 phase, 3 wire, 60 hertz, 460 volt, ac power. Power is provided through the main disconnect switch located on the crane to all motors, drives and controls. There is an additional fusible disconnect switch located on the spent fuel floor to control the power to the crane.
A main line contactor is provided and is operated by stop and reset buttons located conveniently for the operator. A control circuit transformer with fuses provides 110 volt control power to all control panels on the crane with the exception of the main and auxiliary hoist motor Flux Vector Drive systems. Low voltage protection is included.
Overload protection for the motors is included on the individual motor control panels at 125% overcurrent, with the exception of the main and auxiliary hoist motors which are controlled by the Flux Vector Drive computer controls.
The wire sizes are suitable for crane rated motors in accordance with the National Electrical Code. All insulation, conduit and fittings conform to the requirements of the National Electrical Code.
- 9.
Spent Fuel Cask Lifting Device When the shipment of spent fuel is feasible, a special spent fuel cask lifting device shall be used. This device shall conform to the standards of ANSI N14.6-1986 or 1978 and the recommendations of NUREG-0612.
DSAR CHAPTER 9 - AUXILIARY SYSTEMS Revision 36 SECTION 9.11 Page 9.11-21 of 9.11-28
- 10.
Spent Fuel Handling Machine (SFHM)
The spent fuel handling machine, also referred to as the service platform, is a traveling bridge and trolley which spans the spent fuel pool and moves on rails located on the working floor of the spent fuel pool area. The bridge and trolley motions allow coordinate location of the fuel handling hoist and guide assembly over the fuel in the spent fuel pool. The hoist assembly contains a coupling device which when rotated by the actuator mechanism engages the fuel bundle or control rod to be removed. The hoist assembly is moved in a vertical direction by a cable that is attached to the top of the hoist assembly and runs over a sheave on the hoist cable support to the drum of the hoist winch. After the fuel bundle is raised into the mast the spent fuel handling machine transports the fuel bundle to its new location. The controls for the spent fuel handling machine are mounted on a console which is located on the spent fuel handling machine trolley.
Coordinate location of the bridge and trolley is indicated at the console by digital readout devices which are driven by encoders coupled to the 4 guide rails through rack and pinion gears. Manually operated handwheels are provided for bridge, trolley and winch motions in the event of a power loss.
Safety features of the spent fuel handling machine are as follows:
- a.
Zone interlocks which will slow and ultimately stop bridge and trolley motion to protect the mast from hitting SFP walls.
- b.
An interlock that prevents the entry of the SFHM mast carrying a load into a zone adjacent to the south tilt pit when the tilt pit gate is installed and the tilt pit is empty of water. This prevents unacceptable radiation fields in the south tilt pit area.
- c.
Interlocks which restrict simultaneous operation of either the bridge and trolley or the hoist winch drive mechanism.
- d.
An override switch which must be actuated after fuel hoist operation to allow bridge or trolley motion.
- e.
Overload and underload interlocks which stop fuel hoist motion.
- f.
An interlock which prevents positioning of the spent fuel handling machine over the tilting machine unless the tilting machine is in the vertical position.
The SFHM is fitted with an auxiliary hoist for accessing fuel cells that are difficult to reach with the main hoist, such as those in the North Tilt Pit. The manual tool for the auxiliary hoist is also used to move fuel with the Spent Fuel Pool overhead crane.
DSAR CHAPTER 9 - AUXILIARY SYSTEMS Revision 36 SECTION 9.11 Page 9.11-22 of 9.11-28
- 11.
Reactor Building Crane The reactor building crane was originally designed as a 125-ton dual girder, single trolley, indoor electric overhead circular traveling bridge crane (Reference 58). In 1970, it was determined that the Reactor Head, including the Control Rods Drive Mechanisms (CRDMs) and the head lift rig, weighed approximately 133 tons. Additionally, the Hydra-set, used to perform the initial lift of the head from the reactor flange, weighed 2 tons. These components together required a load capacity of 135 tons. Consequently, the crane manufacturer was contracted to re-evaluate (up-rate) the crane for this increased load.
The manufacturer, Dresser, performed the evaluation, and the crane was re-rated to 135-tons with only minor changes to the hoist gear ratio (Reference 59). The structure of the crane was not modified.
Codes and Standards The crane was originally designed, constructed and erected in accordance with the requirements of:
- a.
Electric Overhead Crane Institute (EOCI), Specification #61
- b.
American Welding Society (AWS) Standard Specifications
- c.
National Electrical Manufacturers Association (NEMA)
- d.
American Standards Association (ASA, later ANSI)
- e.
National Electrical Code (NEC)
- f.
National Fire Protection Association (NFPA)
Factors of Safety The following minimum factors of safety, under static full rated load stresses and based on ultimate strength of material were provided:
Material Factor of Safety Cast Iron 12 Cast Steel 8
Structural Steel 5
Forged Steel 5
Cables 5
Welds 5
(Based on ultimate strength of metal in weld)
DSAR CHAPTER 9 - AUXILIARY SYSTEMS Revision 36 SECTION 9.11 Page 9.11-23 of 9.11-28 Load Test The crane was originally load tested to a live load reading of 145 tons (Reference 60). This load reading did not include the weight of the Hydra-set, which weighs 2 tons. Subsequent to the 10-ton up-rate in 1970, the crane was load tested to a load reading of 139 tons. Again, this load does not include the 2-ton Hydra-set weight (Reference 61).
Therefore, the maximum load test load lifted by the up-rated crane was 141 tons.
NUREG-0612 Evaluation In 1983, in association with NUREG-0612, the crane design was re-evaluated by the manufacturer, Dresser, against two newer standards, the Crane Manufacturers Association of America (CMAA),
Specification #70-1975, and the American National Standards Institute (ANSI), Standard B30.2-1976, Chapter 2-1. This review determined that the crane met the intent of all of the mandatory electrical, structural and mechanical design requirements of these new Standards, with one exception. The calculated stress in the end tie, for the case where the capacity load is moved to the extreme end approach, was 5.9% over the CMAA-70 allowable stress of 14.4ksi for these components. This condition was deemed insignificant, and was accepted by the Crane Manufacturer, Consumers and the NRC, in their Safety Evaluation Report (see below).
NUREG-0612 also required licensees to evaluate their crane inspection, testing and maintenance against ANSI B30.2, Chapter 2-2, and that operators be trained, qualified and conduct themselves in accordance with B30.2, Chapter 2-3. Palisades responded that its inspection procedures, and its operator-training program and procedures, meet the intent of these two chapters of this Standard.
The Franklin Research Center, in their Technical Evaluation Report, TER-C5506-378, dated 10/15/1983, accepted Palisades response to NUREG-0612, and stated that load handling operations at Palisades met the staffs objectives. The NRC accepted the recommendations of their contractor in the Safety Evaluation Report issued to Palisades on November 9, 1983 (Reference 62).
9.11.4.4 System Evaluation Underwater handling of spent fuel provides ease and safety in handling operations. Water is an effective, economic and transparent radiation shield and a reliable cooling medium for removal of decay heat.
DSAR CHAPTER 9 - AUXILIARY SYSTEMS Revision 36 SECTION 9.11 Page 9.11-24 of 9.11-28 Basic provisions to ensure the safety of fuel handling operations include gamma radiation levels in the fuel storage areas which are continuously monitored. These monitors provide an audible alarm at the initiating detector and in the control room indicating an unsafe condition.
9.11.4.5 Deleted 9.11.5 SPENT FUEL STORAGE AT AN INDEPENDENT SPENT FUEL STORAGE INSTALLATION Approval to store spent fuel at the original Palisades Independent Spent Fuel Storage Installation (ISFSI) was granted by the NRC via Subpart K of 10CFR72. Palisades chose the Pacific Sierra Nuclear VSC-24 system for the original ISFSI. The VSC-24 system was determined by the NRC to meet the requirements of 10CFR72 by the NRC's issuance of the Certificate of Compliance (C of C) on May 7, 1993. The license for each individual cask expire 20 years from the inservice date. All VSC-24 casks were loaded to C of C Amendment 0. Amendment 0 was renewed effective September 20, 2017 with an expiration date of May 7, 2053.
The VSC-24 system places a Multi-Assembly Sealed Basket (MSB) and a MSB Transfer Cask (MTC) in the cask loading area of the spent fuel pool where the MSB is loaded with spent fuel. Once loaded, the MSB is transported inside the MTC to the cask washdown pit using the fuel building crane, where the MSB is seal welded, dried, and backfilled with helium.
Using the MTC and the crane, the MSB is then transported to track alley, where the MSB is lowered into a Ventilated Concrete Cask (VCC). A Load Distribution System (LDS) is installed in track alley to assure that the load is distributed to the walls supporting track alley. The loaded VCC is then transported along the LDS to a trailer that carries the VSC to the ISFSI where it is stored. The VSC-24 system is described in detail in the Pacific Sierra Nuclear Safety Analysis Report (Reference 21).
In 2003, a new ISFSI pad was constructed to accommodate the entire Palisades spent fuel inventory generated through 2011, including the casks stored at the existing VSC-24 ISFSI pad. This ISFSI pad was designed for storage of a new dry cask system manufactured by Transnuclear, Inc.,
Standardized NUHOMS Horizontal Modular Storage System, as well as the VSC-24 casks. The NUHOMS system is also licensed under 10CFR72, Subpart K and has a service life of 50 years.
DSAR CHAPTER 9 - AUXILIARY SYSTEMS Revision 36 SECTION 9.11 Page 9.11-25 of 9.11-28 The NUHOMS Horizontal Modular Storage System provides for the horizontal storage of canisterized spent fuel assemblies in a concrete horizontal storage module (HSM). The NUHOMS Storage System components consist of a reinforced concrete HSM and a dry shielded canister (DSC) confinement vessel with an internal basket assembly that holds the fuel assemblies. The DSC and the HSM for the Standardized NUHOMS Horizontal Modular Storage System for Irradiated Nuclear Fuel (Reference 50) are described in the NUHOMS FSAR.
The HI-STORM FW MPC Storage System developed by Holtec International is also in use. The system consists of the following components: (1) an interchangeable multipurpose canister (MPC), which contains the fuel; (2) a storage overpack (HI-STORM FW), which contains the MPC during storage; and (3) a transfer cask (HI-TRAC VW), which contains the MPC during loading, unloading and transfer operations. The MPC stores up to 37 pressurized water reactor fuel assemblies. The HI-STORM FW MPC Storage System provides for the storage of an MPC in an overpack in a vertical position on the ISFSI.
The HI-STORM FW MPC Storage System is described in the Final Safety Analysis Report (Reference 79) and is certified in Certificate of Compliance No. 1032 (Reference 80).
9.11.5.1 Description Of 10CFR72 License Items Which Interface With The 10CFR50 License This section describes various ISFSI items licensed under 10CFR72 that interface with equipment licensed under 10CFR50.
9.11.5.1.1 Multi-Assembly Sealed Basket And Transfer Cask The MSB and MTC shell and internals are coated to prevent detrimental effects on fuel pool water chemistry during the time that the MSB and the MTC are in the pool. The MTC shell and internals and the outer shell of the MSB are coated with a paint that facilitates decontaminating the MTC and the MSB upon removal from the pool.
The MTC and the MTC yoke are special lifting devices designed and fabricated to the requirements of NUREG 0612 and ANSI N14.6 per the Certificate of Compliance. The lifting of the MTC is performed under site-specific heavy load requirements that conform to the recommended guidelines of NUREG 0612 and Generic Letter 85-11.
DSAR CHAPTER 9 - AUXILIARY SYSTEMS Revision 36 SECTION 9.11 Page 9.11-26 of 9.11-28 9.11.5.1.2 Transnuclear 32PT-S125 DSC, 24 PTH-S125 DSC and OS-197 Transfer Cask The Transnuclear OS-197 transfer cask is designed for onsite transport of the 32PT-S125 DSC and 24 PTH-S125 DSC to and from the plants spent fuel pool and the ISFSI. The transfer cask provides the principal biological shielding and heat rejection mechanism for the DSC and spent fuel assemblies during handling in the fuel building, DSC closure operations, transport to the ISFSI, and transfer into the Horizontal Storage Module (HSM or HSM-H). Two lifting trunnions are provided for handling the transfer cask in the plants fuel building using a lifting yoke and an overhead crane. Lower support trunnions are provided on the cask for pivoting the transfer cask from/to the vertical and horizontal positions on the support skid/transport trailer. According to the Transuclear FSAR, the transfer cask upper trunnions and trunnion sleeves are designed in accordance with ANSI A14.6 requirements for non-redundant lifting devices. The Transnuclear lifting yoke is designed and tested to the requirements of ANSI N14.6 and NUREG-0612.
The DSC and OS-197 components are primarily constructed of stainless steel materials to prevent detrimental effects on the fuel pool water chemistry during loading and unloading operations.
9.11.5.1.3 HI-STORM FW MPC and Transfer Cask The MPC enclosure vessel is a fully welded enclosure, which provides the confinement for the stored fuel and radioactive material. Each MPC is an assembly consisting of a honeycomb fuel basket, a baseplate, a canister shell, a lid, and a closure ring. The MPC baseplate and shell are made of stainless steel. The confinement boundary is defined by the MPC baseplate, shell, lid, port covers, closure ring, and associated welds.
The Holtec HI-TRAC VW transfer cask shields and protects the MPC during loading, unloading, and movement of the MPC from the cask loading area to the storage overpack. The transfer cask is a multi-walled (carbon steel/lead/carbonsteel) cylindrical vessel with a neutron shield jacket attached to the exterior and a retractable bottom lid used during transfer operations.
All lifting appurtenances used with the HI-STORM FW MPC, transfer cask, and overpack are designed in accordance with NUREG-0612 and ANSI N14.6, as applicable.
DSAR CHAPTER 9 - AUXILIARY SYSTEMS Revision 36 SECTION 9.11 Page 9.11-27 of 9.11-28 9.11.5.1.4 Impact Limiting Pads For the VSC-24 system, impact limiting pads (ILPs) can be placed in the spent fuel pool and the cask washdown pit to support fuel loading, if the crane is not used in accordance with single failure proof requirements. The required pressure ratings for the foam in each of the ILPs was determined by calculating the critical pressures on the slabs beneath the cask loading area and the cask washdown pit. These critical pressures were used to determine the minimum strength of the foam to be placed in the ILPs. Also, the bottom of the spent fuel pool ILP is designed with groove areas to prevent any load from bearing on the pool liner welds. Since the main hoist of the spent fuel crane is now single failure proof, impact limiting pads are not required in the cask loading area of the spent fuel pool and the cask washdown pit when the crane is used in conformance with single failure proof requirements.
9.11.5.1.5 Security For The Independent Spent Fuel Storage Installation The security system for the VSC-24 ISFSI was installed under Facility Change FC-925 and was later upgraded under the engineering change process. The system was constructed and is maintained per the requirements of 10CFR50 and 10CFR72 Subpart H.
The Transnuclear NUHOMS ISFSI facility is protected separately and is approximately 2400 feet from the plant Protected Area. The security system for this ISFSI was included as part of the overall ISFSI construction project under Engineering Assistance Request EAR-2000-0309. The tie-ins to the existing plant security system were completed under EAR-2002-0317. This ISFSI security system was later upgraded under the engineering change process.
9.11.5.1.6 Lifting Equipment The design and description of the rigging equipment used to handle the VSC-24 and the Transnuclear NUHOMS system components in the auxiliary building is described in References 18 and 48, respectively. The requirements of NUREG-0612 and ANSI N14.6 were applied to this lifting equipment as appropriate.
The design and description of the rigging equipment used to handle the MPC-37 and the Holtec HI-STORM FW MPC Storage System components in the auxiliary building is provided in Reference 79. The requirements of NUREG-0612 and ANSI N14.6 were applied to this lifting equipment, as appropriate.
DSAR CHAPTER 9 - AUXILIARY SYSTEMS Revision 36 SECTION 9.11 Page 9.11-28 of 9.11-28 9.11.5.1.7 Spent Fuel Pool Boron And Temperature Limits The Certificate of Compliance (C of C) for the VSC-24 system requires that the spent fuel pool boron concentration be greater than or equal to 2850 ppm during cask loading and unloading activities (Reference 19). The required spent fuel pool boron concentration for the Transnuclear NUHOMS system is 2500 ppm during loading and unloading activities (Reference 50). This ensures that a subcritical configuration is maintained in the case of accidental loading of the MSB or DSC with unirradiated fuel.
For the VSC-24 system, the reaction between carbo zinc primer and borated spent fuel pool water will generate a hydrogen gas and produce zinc borate precipitates that can result in boron depletion. Controls are provided during loading and unloading activities to prevent the hydrogen gas from reaching an explosive level, and to insure that the boron concentration will not be reduced below the C of C limit of 2850 ppm.
The Transnuclear NUHOMS system design includes the use of aluminum plate, which reacts with the borated spent fuel pool water to form hydrogen gas. As with the VSC-24 system, controls are provided during loading and unloading activities to prevent the the hydrogen gas from reaching an explosive level.
The Certificate of Compliance for the MPC-37 HI-STORM system provides requirements for the spent fuel pool boron concentration during cask loading and unloading activities (Reference 79). These limits ensure that a subcritical configuration is maintained in the event of accidental loading of the MPC with unirradiated fuel.
DSAR CHAPTER 9 - AUXILIARY SYSTEMS Revision 36 SECTION 9.12 Page 9.12-1 of 9.12-3 9.12 ULTIMATE HEAT SINK 9.12.1 DESIGN BASIS The Ultimate Heat Sink structures and components are designed to provide water from Lake Michigan to the suction side of various Plant pumps. Lake Michigan is the ultimate water source for the removal of decay heat from irradiated fuel assemblies. Following use, the water and waste heat is returned the Lake Michigan through the discharge structure.
Structures, systems and components making up the ultimate heat sink supply are designed to CPCo Design Class 3 and are considered to be non-safety related with the exception of portions of the Intake Structure, which are designed to CPCo Design Class 1 requirements.
The Ultimate Heat Sink and associated structures, systems and components provide a support function to other systems by supplying screened water from Lake Michigan to the Service Water System discussed in Section 9.1, Fire Water System discussed in Section 9.6 and the Circulating Water System/Dilution Water discussed in Section 10.2.4.
9.12.2 SYSTEM DESCRIPTION AND OPERATION 9.12.2.1 System Description Lake water enters the system through an intake crib located off shore, approximately 3000 feet from the Plants intake structure. The intake bell, located under the intake crib, is in approximately 25 feet of water. Actual submergence varies based on Lake Michigan water level. The water enters the intake crib and travels through a carbon steel line buried in the lake bottom. Near the intake structure, the line divides into two flow paths, one entering the north and the other entering the south intake structure bays. The flows pass through separate trash racks and traveling screens ensuring that debris is removed prior to reaching pump intakes. Capability to isolate the flow through the use of stop logs is provided upstream from the traveling screens. The two dilution water pumps and one diesel fire pump take suction from this portion of the intake structure (Figure 9-1 Sheet-2, Figure 9-11 Sheet-1 and Figure 10-6).
Water supplying the service water pumps and the remaining firewater pumps flows from the two intake bays through sluice gates into the service water pump intake bay. All three service water pumps, the screen wash pump, the electric fire pump, one diesel fire pump and the fire system jockey pump take suction from the service water intake bay (Figure 9-1, Sheet-2 and Figure 9-11 Sheet-1).
DSAR CHAPTER 9 - AUXILIARY SYSTEMS Revision 36 SECTION 9.12 Page 9.12-2 of 9.12-3 The capacity of the Plants intake from Lake Michigan greatly exceeds the combined capacity of all the pumps that use the lake as a source of water.
The intake was originally designed for the much larger flow rates required to support once-through condenser cooling. The once-through cooling was converted to a closed loop cooling tower design early in the Plants life. Two of the original four trash rack and traveling screen combinations, however, were removed from service by installing their associated stop logs. The associated traveling screens were then removed and replaced with dilution water pumps in support of the cooling tower configuration and plant discharge requirements.
The traveling screens are normally washed by a dedicated pump. An alternate screen wash water source is provided by the fire protection pump test header.
The water intake is periodically treated to reduce biological growth that can affect long term operation of various heat removal systems (Figure 9-1, Sheet-2).
Level transmitters are provided in the intake structure. The transmitters support local level indication, provide actuation of the traveling screens and provide control room indication and alarm.
After cooling Plant equipment, service water and excess dilution water effluent is released back to the lake, flowing from the makeup basin out through the discharge structure. The two makeup basins are connected by an isolatable path through the warm water recirculation pump suction bay.
In addition, a 36 inch diameter line was designed to allow alignment of the warm water recirculation pump suction bay to either the mixing basin or directly to Lake Michigan. Flow back through the discharge structure into the mixing basin is now the only credited flow path from Lake Michigan. Though part of the design, the valve on the Lake Michigan side of the discharge structure is not tested due to sand intrusion and sand blockage concerns.
Use of either path is limited by lake level (Reference 47). The alignment of the recirculation pump suction to the lake provides an optional source of water to the intake structure in the unlikely event the intake line from the Lake Michigan is lost.
9.12.2.2 System Operation During the various facility operating configurations, supported pumps take suction as needed. Flow varies based on head differences that occur as various pumps take water at their intake points thereby reducing water level in the intake structure when compared to the lake.
During operation, the intake bay level is monitored and should low level conditions occur, an alarm will alert the control room to take appropriate action.
DSAR CHAPTER 9 - AUXILIARY SYSTEMS Revision 36 SECTION 9.12 Page 9.12-3 of 9.12-3 The warm water recirculation pump can be aligned to supply water from the discharge structure to the intake structure should the intake line be blocked for any reason.
9.12.3 SECTION DELETED