LR-N17-0034, Salem Generating Station, Units 1 & 2, Revision 29 to Updated Final Safety Analysis Report, Section 9.4, Heating, Ventilation, and Air Conditioning Systems

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Salem Generating Station, Units 1 & 2, Revision 29 to Updated Final Safety Analysis Report, Section 9.4, Heating, Ventilation, and Air Conditioning Systems
ML17046A466
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LR-N17-0034
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9.4 HEATING, VENTILATION, AND AIR CONDITIONING SYSTEMS 9.4.1 Control Area Air Conditioning System The Control Area Air Conditioning System (CAACS) and the Control Room Emergency Air Conditioning System (CREACS) are designed to maintain room temperatures within limits required for operation, maintenance and testing of plant controls, and permits continuous occupancy under normal and design accident conditions. 9.4.1.1 Design Bases The CAACS maintains the control room area ambient temperatures of 76°F dry bulb and a maximum of 50 percent relative humidity based on outside air temperatures ranging from 0°F winter dry bulb to 95°F summer dry bulb and 78°F summer wet bulb during normal and emergency conditions. The CREACS maintains room ambient temperatures inside the Control Room Envelope (CRE) within 55° to 85°F during emergency conditions, except for the Data Logging Rooms which are maintained within 55°F to 90°F, based on outside air temperatures ranging from 0°F winter dry bulb to 95°F summer dry bulb and 78°F summer wet bulb during emergency conditions. In addition, the CAACS/CREACS design bases provides for the following: (1) Protection of the CRE and control room areas (relay and control equipment rooms) from infiltration of fire, smoke, or airborne radioactivity by use of minimum leakage penetrations, weather stripped doors, absence of outside windows, and by maintenance of a positive pressure during normal operation. (2) Protection of the CRE from a radiological design bases accident by filtering airborne activity and maintaining the CRE at a combination of 1/8 inwc and 1/16 inwc positive pressure differential above the outside environment and adjacent rooms. The dp is 1/8 inwc for all adjacent areas except the relay rooms, which is 1/16 inwc. (3) Protection from airborne toxic gas or hazardous chemical releases outside the control room area. ( 4) Protection from the smoke generated inside or outside the control room area. (5) Maintains ambient temperatures within 55° to 85°F in the control room and adjoining equipment room for personnel comfort and instrument accuracy; from 65° to 85°F in the Relay Room and Unit 2 125 VDC Battery Rooms; and from 65° to 95°F in the Unit 1 125 VDC Battery Rooms during normal plant operating conditions. (6) Remains operable during a design basis seismic event. 9.4-1 SGS-UFSAR Revision 28 May 22, 2015 9.4.1.2 System Description The control room area for each unit consists of the unit control room, a data logging room, a control equipment room, and a relay room. The operator ready room, conference room, control room supervisor's office areas, and both units control rooms are located in a common protected area or Control Room Envelope (CRE). The CRE area is serviced by both units CAACS during normal operating conditions and both units CREACS during emergency conditions. Normal access to the control area is attained through the Auxiliary and Service Buildings. The control area is enclosed in a Class I (seismic) structure. The air handling equipment for each control area is housed in the equipment room adjacent to its respective control room inside the Auxiliary Building. The seismic design and analysis methodologies used to qualify all ductwork and the contained equipment are described in Section 3.8.4.4.1. The CAACS is shown in Plant Drawings 2 0524 8 and 2 0534 8. The area adjacent to the control room area (which is comprised of the work control center, field SRO office and a toilet room) is separated from the control room area envelope, does not contain any safety related equipment and is therefore provided with an independent non-safety related system consisting of a roof-top heating and cooling unit, a toilet exhaust fan, and non-seismically supported ductwork, which are also shown on Plant Drawing 205248. The CAACS consist of a filter enclosure equipped with medium and low efficiency filters, three vane-axial fans (one standby), a multi-zone coil unit with three cooling coils and one heating coil, air distribution ducts and electrically or pneumatically operated dampers (with manual backup operators). Each CAACS primarily serves its units equipment ready room, control room supervisor control rooms are serviced by both smoke generated inside the CRE. room and relay room areas. The operator areas, and both units' data logging and units CAACS during normal operation and The CREACS, a portion of the CAACS, operates to ensure continuous occupancy of operating personnel in the CRE under emergency conditions. The CREACS supplies cooled high-efficiency particulate air (HEPA) and charcoal filtered air to the CRE when actuated by the Solid State Protection System (SSPS) or control room intake high radiation signal. The CREACS consists of a filter enclosure equipped with HEPA and charcoal filters, a cooling coil, two vane-axial fans (one standby), supply and return ducts to the control room envelope, outside air intakes (crosstied between unit 1 and 2 CREACS filter units), distribution plenum above the control room conference room, and electrically or pneumatically and manually operated dampers. 9.4-la SGS-UFSAR Revision 27 November 25, 2013 Both units CREACS operates simultaneously in pressurized mode during a radiological design bases accident and in full recirculation mode during a toxic gas, hazardous chemical release, or smoke generated inside the control room area. Provisions in the design provide for a single CREACS train to be operated and provide long term occupancy in the CRE during a radiological condition. The CAACS and CREACS cooling coils are supplied with chilled water from the Chilled Water System located in each unit's mechanical equipment area located at elevation 100 foot of the Auxiliary Building. Each unit's Chilled Water System consists of three 50% capacity package chiller units, two 100% capacity recirculating pumps, condensers cooled by the service water system (SWS), and interconnecting refrigeration, service water and chilled water piping. The Unit one's Chilled Water System has a side stream demineralizer to maintain water chemistry and a recirculation line from the No. 12 chilled water pump (1CHE6) to the No. 1 chilled water expansion tank (1CHE1) drain line to prevent stagnant water conditions in the tank. The demineralizer and recirculation line are added as a part of the Unit 1 plant life extension commitments. The Chilled Water System has ample capacity to cool the areas serviced by CAACS and CREACS during normal and emergency operating conditions. During single CREACS train operation, the associated cooling coil is provided with sufficient chilled water with two chillers in service to maintain temperatures inside the CRE below 85°F at outside summer design conditions, except for the Data Logging Rooms, which are maintained below 90°F. The air conditioning equipment is designed to Class I (seismic) criteria and can be energized from the standby ac power supply. Depending on outside climatic conditions, one or two CAACS fans per unit are normally in operation, the third serving as standby. The CREACS is isolated and in standby during normal operation. The CAACS normally operates with a fixed amount of outside air to maintain a slight positive pressure in the CRE. The control area ventilation system has four modes of operation. follows: They are as Normal (Mode 1) This is the operating mode for CAACS during normal plant operations. In this mode, a mixture of outside air and recirculated air is supplied to the control room areas (relay room, equipment room, and the CRE) to maintain design temperature conditions within limits. Typically, one or two supply fans are operating with the third acting as a backup. The outside makeup (CAA40 & 43 open) and recirculated air is mixed and filtered through roughing filters, cooled (or heated), and supplied to the control room areas. The CRE and control room areas (relay and control equipment rooms) are maintained at a positive pressure. The CREACS is isolated and in standby. 9.4-1b SGS-UFSAR Revision 29 January 30, 2017 Fire Inaide control area <Mode 21 In the event of a fire or amoke generated in the control room, each units CAACS is manually initiated by the operators for once through, 100\ outside air operation or purge. In this mode, all of the intake (CAA40, 41, 43 & 45) and exhauat dampers (CAA18 & 19) open and return damper (CAAS) closed to allow 100\ outside air to be pumped through the control room areas and expelled to the outside, thereby making the control room habitable. A maximum of two CAACS supply fans can be operating in thia mode. Roughing filters are used for filtering the outside air. The CRBACS is isolated and in standby. Fire Qutside control Area <Mode 3) In the event of airborne toxic gaa, hazardous chemical releasea, or amoke from outaide the control room, provisions are made for 100\ recirculated air. In this mode, all of the intakea (CAA40, 41, 43 & 45), emergency intakes (CAA48, 49, SO & 51) and exhauat (CAAlB & 19) dampers are cloaed iaolating the ventilation systems from the outside environment. The Unit 1 and 2 CAACS are isolated from the CRE (by closure of CAA14 and CAA20 dampers) and operates in the full recirculation supplying cool air to the relay and equipment rooma, while both unit

  • s CRBACS operate to recirculate air to the CRE. A maxilnum of two CAACS supply fane and one CREACS aupply fan per unit can be operating in this mode. Chilled water control valve CR74 open and CH168 ia open to aupply chilled water to the CAACS and CREACS coils, respectively. Recirculated air to the control room envelope paaaes through a cooling coil and high efficiency particulate air (HEPA) and charcoal filter banks. This mode is manually initiated by the operators from both control rooms. Accident Presaurized -Two Filtration Train Alignment tMode 4J A mode of operation has been provided in the event of airborne radioactivity and long occupancy of the control room. In this mode, all of the intake (CAA40, 41, 43 & 45), exhaust (CAA18 & 19), and eRE boundary (CAA14 and CAA20) dampers are closed isolating both units CAACS from the outside environment and the CRE. Chilled water control valve CH168 is open. The CAACS operates in Mode 3 with CR74 valve open. An emergency intake from one unit will open and the opposite will remain closed based on which unit initiated the accident signal. Both CREACS filtration trains will start with one fan operating in each unit. If one of the fans fails to start, the standby fan will automatically start. 9.4-2 SGS-UFSAR Revision 16 January 31, 1998 -

Each CREACS filter unit will draw in 1100 scfm of outside air mixing with 7000 scfm recirculated air from the CRE. The total of 2200 scfm makeup air ensures that the CRE is pressurized to greater than a combination of 1/8 inwc and 1/16 inwc differential above the outside environment and adjacent rooms. The dp is 1/8 inwc for all adjacent areas except the relay rooms, which is 1/16 inwc. The recirculated air and outside makeup air is filtered through HEPA and charcoal filters to remove airborne radionuclides and is cooled by a cooling coil. The CAACS operates in Mode 3 recirculating air to control room areas outside the CRE. The CAACS and CREACS automatically actuates upon an accident signal (SI or high radiation) and selects the preferred emergency intake. In the event that the automatic selection of the preferred intake is unavailable, the operator can manually place the CREACS into Mode 4 service with the preferred emergency intake selected to any unit at power or shutdown. Single Filtration Train Alignment The control area ventilation system has provisions to allow for a single CREACS train to be out of service for maintenance. In this alignment, a single CREACS filter train is capable of providing ample cooling, filtering of recirculated and makeup air, and pressurization of the CRE to ensure continuous occupancy of personnel in the control room. In this standby alignment, one CREACS train on one unit is isolated and the other train is aligned (using manual dampers) for cooling the entire CRE with the CREACS train in standby. In this alignment, while in the standby condition, the CAACS fans on the side where CREACS is aligned continues to supply cooling to its respective Electrical Equipment Room/Relay Room (EER/RR) as well as the entire CRE. On the side where the CREACS is isolated, the CAACS supplies only it's EER/RR. If an accident were to occur, the system would automatically align as described in the Accident Pressurized Mode (Mode 4) except one CREACS train is now aligned to supply the entire CRE. The manual dampers (VHE1058, VHE1130, VHE1133 and VHE1141) when positioned ensure that a total of 2200 scfm of makeup air is provided and that supply air is distributed throughout the CRE. Return damper CAA17 on the CREACS unit aligned to the Single Filtration Train mode is administratively controlled to the open position. The air intake dampers must remain capable of automatically actuating and aligning the outside air intake to the non-accident unit's intake damper, upon receipt of a Safety Injection (SI) or a High Radiation signal, when both units are in modes 1-4. 9. 4-3 SGS-UFSAR Revision 24 May 11, 2009 SYSTEM CONTROLS Both Units l and 2 control room ventilation systems are designed to initiate Mode 4 operation automatically upon any one of the following signals: (1) Safety Injection signal from Unit l (2) Safety Injection signal from Unit 2 (3) High outside air activity from Unit 1 control room intake monitor (4) High outside air activity from Unit 2 control room intake monitor The automatic selection of emergency intake dampers that open during Mode 4 operation is based on the following: ( 1) ection or control room intake high radiation signal from Unit 1 will open emergency intake dampers on Unit 2 (Unit 1 remain closed). (2) Safety Injection or control room intake high radiation signal from Unit 2 will open emergency intake dampers on Unit 1 (Unit 2 remain closed}. The following monitoring devices are provided for the control room ventilation system: ( 1) Smoke detectors are provided to detect trace amounts of combustion products (2) Two safety related outside air activity monitors per intake monitor air entering the control room supply duct. These monitors are beta scintillation type detectors with a range of 101 -107 cpm. These monitors have an instrument failure alarm, indication in the control room, and alarm to the control room. The same radiation monitor that generates the alarm is also used for automatic initiation of Mode 4 to isolate and pressurize the CRE. (3) One non-safety related area monitor per unit is mounted in the control room. These monitors are GM type detectors with a range of 10-1 -104 mR/hr (Unit 1) and 10-1 -106 mR/hr (Unit 2). These monitors have an instrument failure alarm, local readout, and alarm to the control room. This monitor serves to provide indication only in the control room. 9.4-4 SGS-UFSAR Revision 19 November 19, 2001 --

The dampers actuated in the CAACS and CREACS are pneumatically controlled and have position indication in the control room for vital automatic dampers. The dampers required to operate during Mode 4 conditions are designed to fail to their designated position upon loss of control air or power. These dampers actuate to the designated positions upon signals from the Solid State Protection System (SSPS) and the radiation monitoring system (RMS). All vital dampers can also be operated manually at the damper. The control room ventilation system has provisions to allow the operators to manually initiate the CAACS and CREACS to any of the operating modes from the control room. 9.4.1.3 9.4.1.3.1 CREACS Single Failure Design The CREACS ventilation design has been evaluated for single failure vulnerabilities and impacts on control room habitability requirements during an accident. The CAACS and CREACS designs provide for redundant pneumatically operated isolation dampers (with manual backup operators) and controls for isolating the outside environment from the control room areas. These dampers are designed to fail to their designated positions for Mode 4 accident operation as described in 9.4.1.2. In addition, each unit's emergency intakes are provided with dual parallel flow paths, each with redundant pneumatically operated dampers in series with a manual isolation damper for maintenance. These pneumatic dampers are with redundant actuation and are supplied from separate control air headers to ensure that emergency makeup air is supplied to pressurize the CRE during an accident. 9.4-4a SGS-UFSAR Revision 19 November 19, 2001 Dampers not providing isolation from the outside environment are single pneumatically operated dampers. Dampers relied upon during emergency conditions are provided with redundant actuation signals and are spring loaded to their fail safe positions upon a loss of control air or power (CAA14, CAA17, CAA20). These dampers are also provided with manual backup operators and position indicators in the control room. Operation of required dampers, valves and fans during an emergency condition is ensured by providing redundant controls. Each unit consists of two trains of controls circuitry supplied from separate vital control power and control air sources. The control scheme is designed such that on a loss of control power or air, the CAACS and CREACS will fail safe to the designated position for Mode 4 operation. Each unit's controls are initiated from redundant trains of SSPS and control room intake radiation monitors. Each CREACS filtration train is provided with two 100% capacity supply fans supplied by the standby A/C power supply. In the event that one fan fails to start, a safety related flow switch located downstream of the fan discharge duct will start the standby supply fan. Control switches located in the control room are provided to allow the operators to select the lead and standby emergency fans. In the event maintenance is required on a filter unit, the operators manually place the system in the standby alignment condition for a single CREACS filtration train operation. In the Maintenance mode, a single CREACS filtration train is capable of providing adequate cooling, removal of airborne activity, and pressurization of CRE during the course of an accident for long term occupancy. While in the Maintenance mode, CREACS return damper CAA17 is administratively blocked open. 9.4-4b SGS-UFSAR Revision 17 October 16, 1998 -

9.4.1.3.2 Shared Systems. Structures. or Components Since the SGS Unit 1 and 2 control rooms are common, the ventilation design and operating modes for CAACS and CREACS are evaluated for impacts for shared system design (GDC 5). The fallowing areas of the ventilation design were evaluated: (1) Supply Distribution Plenum to CRE (2) Outside Emergency Intake Plenum (3) Unit 1 and 2 CREACS supplying CRE (4} Single Filtration Train operation (Maintenance mode) (S) Ventilation Control Circuitry (6) Control Room Intake Radiation Monitors Supply Distribution Plenum to CRE This supply distribution plenum and associated manual dampers are designed to Class I (seismic) criteria. This common supply plenum serves to distribute air to the rooms within the CRE. Outside Emergency Intake Plenums The emergency air intake plenums for each unit is cross-connected by a common ductwork to allow each unit's CREACS or a single unit's CREACS the ability to draw outside makeup air from the selected or preferred intake. The emergency air intake and distribution plenums are designed to Class I (seismic) criteria. The emergency air intake plenums for each unit are designed with dual parallel flow paths, each flow path consisting of a redundant series of dampers actuated by redundant controls. The sources of power and control air for each unit's intake dampers are not shared between units. CREACS Supplying CRE Normally, during an emergency condition, both units CREACS will operate simultaneously, each CREACS supplying cool filtered air to the CRE to maintain habitability requirements. 9.4-4c SGS-UFSAR Revision 16 January 31, 1998 In the event that one CREACS filtration train is out of service for maintenance, the operators manually place the system in the standby alignment condition to a single filtration train operation (Maintenance mode). A single CREACS train is capable of providing adequate air to cool the CRE and ensures control room habitability requirements are met during an accident. The controls for actuating the CAACS and CREACS to the accident mode of operation (Mode 4) and for single filtration train alignment are shared between Unit 1 and 2 control area ventilation control circuitry. This is based upon each unit's train of control being electrically interlocked with the opposite unit's controls. This interlock enables the opposite unit's CAACS and CREACS controls to automatically initiate to Mode 4 operation. This interlock is electrically isolated and separated from the other unit's control power. The pneumatic controls are completely separated and are not cross-connected between units. Each unit's actuation controls are redundant, and electrically and physically separated. The interlock between units is electrically isolated and is only interconnected to the same division or train on the opposite unit. The control air and electrical power sources are not shared between units, and therefore, the onsite power system capacities are not impaired. _ Control Room Intake Radiation Monitors The radiation monitors monitor both unit's intake and provide actuation functions to Unit 1 and 2 ventilation controls and are considered shared. These monitors are redundant and safety related. A monitor is located in each unit and is of moni taring normal makeup air on each unit

  • s intake plenums. Therefore, each unit's intake plenum consist of redundant detectors from separate radiation monitors located in different units. The power sources to these monitors are not shared between units and the actuating functions to both unit's ventilation controls are separated and isolated. The shared ductwork is designed to seismic I criteria and will maintain its safety function during an accident. 9.4-4d SGS-UfSAR Revision 19 November 19, 2001 The capacity of the onsite power sources are not impaired by the sharing of the control area ventilation system. In the cases evaluated herein, the power sources for the ventilation equipment (fans) and controls (relays, solenoids, damper actuators) are not shared between Units 1 and 2. In fact, the sharing is based on the function of the sse being shared between the units, in which case, provisions in the design ensures for adequate separation and isolation between units sse and redundancy of the shared sse, such that the safety function is not impaired per GDC-5 criteria. 9.4.1.3.3 Detection of Adverse or Dangerous Environment Conditions The control room is provided with smoke detectors and radiation detectors located in the control room and in the normal intake plenums. The smoke detectors monitor for trace amounts of combustion and alarm to the control room. Redundant radiation monitors are provided that monitor the normal incoming makeup air to the control room areas for airborne radioactivity. A radiation monitor is also provided in each control room that serves to provide radiation levels in the area. Human detection by the control room operators is also relied upon for the detection of other hazardous conditions (e.g., smoke, ammonia, etc.). 9.4.1.3.4 capability to Exclude contaminants The CAACS and CREACS is designed to cope with preventing the entry of contaminants by operating in the following modes: (1) CAACS in Normal operation (Mode 1) with outside makeup air maintains a positive pressure inside the control room areas and the CRE during normal operation and use of minimum leakage dampers, minimum leakage penetrations, weather stripped doors, and absence of outside windows to limit infiltration of air, smoke or airborne radioactivity from other rooms in the control area and Auxiliary Building. The CAACS does not use exhaust fans and relies on the supply fan pressure to deliver air flow into the room areas. With this design, minimizing leakage in the rooms and makeup air, the control room areas can be maintained at a positive pressure limiting entry of contaminants. ( 2) Full recirculation (Mode 3) of CAACS and CREACS with the outside environment isolated due to smoke, toxic gas, or hazardous chemical released outside the control room. This mode is initiated manually by the operator upon detection. 9.4-4e SGS-UFSAR Revision 16 January 31, 1998 (3) CREACS pressurizing (Mode 4) the CRE and CAACS in full recirculation for radiological accident. This mode can be initiated automatically or manually. 9.4.1.3.5 Capability for Removal of Contamination The CREACS filtration train consists of a High Efficiency Particulate Air (HEPA) and charcoal filters. The HEPA filters have a removal efficiency of 95% and the charcoal filters have a removal efficiency for radioiodine of 95%. The Unit 1 and 2 CREACS filtration units will automatically be placed in service during a radiological accident, filtering recirculated air from the eRE and makeup air from outside the control room. In addition, a single CREACS filtration train, when operated in the Maintenance mode, is capable of providing adequate removal of airborne contaminants during an accident to ensure the doses in the CRE are within the limits of GDC 19 criteria. 9.4.1.3.6 Removal of Contamination by Purging Purging of the control room areas is provided by the operators manually initiating the system to the Mode 2 operation. In this mode, all of the normal outside air intake plenum dampers go open, providing 100% outside air to be drawn into the control room areas. Exhaust dampers go open to allow the contaminants to be expelled to the outside environment. The CREACS is isolated and in standby in this mode. 9.4.1.3.7 Capability of Ensuring Ambient Room Temperatures The control area ventilation system has adequate capacity to ensure ambient temperatures in the rooms are maintained within limits during normal and emergency conditions. A system air balance was performed and adjustments made for the required design values. A chiller capacity test was performed on one of the chillers. A system balance on the CWS was performed. Inspection on the CREACS coils was performed. These tests reasonably demonstrate the capability of the system to remove the heat loads during normal and emergency conditions to maintain the control room areas and the CRE within temperature limits. 9.4.1.3.8 Capability for Single CREACS Filtration Train In the event that one of the unit's CREACS filtration trains require maintenance, the operators manually place the system in the standby alignment condition to operate with a single CREACS filter train (Maintenance mode). once the CREACS unit is in the Maintenance mode, an automatic initiation will initiate accident pressurized and will pressurize the CRE and maintain control room habitability during the course of an accident within GDC 19 limits. 9.4-4f SGS-UFSAR Revision 17 October 16, 1998 --
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  • 9.4.2 Auxiliary Building Ventilation System 9.4.2.1 Design Bases The Auxiliary Building Ventilation System is designed for long-term continuous operation during normal and emergency modes of plant operation to provide consistent levels of temperature, cleanliness, and negative pressure within the building. Standby equipment is included in the system to assure the maintenance of design conditions within the building and thus preclude the uncontrolled release of radioactivity to the environs. The use of the Auxiliary Building exhaust filtration (HEPA and charcoal filters) to reduce release of radioactivity after the design basis accidents of Section 15 was eliminated. The accident dose analyses were re-done using an alternative source term in accordance with Regulatory Guide 1.183 (Ref. 1). The radioactivity released into the auxiliary building during these accidents was analyzed as being released by the Auxiliary Building Ventilation System through the plant vent without filtration. Limitations on the operability and use of the Auxiliary Building Ventilation System HEPA and charcoal filters are to ensure that they are used to reduce releases of radioactivity in normal plant operation in conformance with Appendix I to 10 CFR Part 50 (Ref. 3)
  • Limitations on the dose to areas beyond the SITE BOUNDARY conform to the doses associated with 10 CFR Part 20, Appendix B, Table II, Column 1 (Ref. 2) and environmental radiation releases from the uranium fuel cycle sources conform to 40 CFR Part 190 (Ref. 4). Gaseous releases during normal operation are done in accordance with the Salem Units 1 and 2 Offsite Dose Calculation Manual (ODCM) (Ref. 5) limits . 9.4-5 SGS-UFSAR Revision 23 October 17, 2007 I Auxiliary Building Ventilation equipment is utilized in performing contuinment purging. Containment purging is an intermittent where sampling and requirements, prior to each purge, are performed in accordance with the ODCM (Reference 5). The equipment in the Auxiliary Building VentLlation System is available to purge the containment normal reactor shutdown. Containment purging is limited by administrative controls as described in Section 9.4.4.3.1. 'rhe tota.l capacity of fans and Li.lten-: is for the maximum ventilation rate. 'J'bat is, total y is based on summertime ventilation of tbe Auxiliary Building during normaJ power operation. '!'his sy::;tem operates to Li.mit the average tempeJ:ature of the Auxiliary Building to ll0°F' or less, and to maintain the Auxiliary Building boundary at a slight negative pressure. 'I'he l\u:xiliary Building Ventilation System is designed to maintain a year-round range of average temperatures within the Auxiliary Building of 60-1.10°F. T'hi.s is the temperature range chosen to size the ventilation equipment and not the space Bui.J.d:i.nq equipment has been evaluated to operate at area Hot wat:er coils in the supply a:i.r units are designed to provide 60°li' air to the Auxiliary Building :Ln winter and no less than 45°F air to the Containment Building. The design basis outdoor temperc1ture is 0°F' (winter) and 95°F (summer). Both values satisfy more than 99 percent of the conditions experienced at the s1te area annually. A 24, 000 cfm capac.l. ty charcoal filter is of the l<.:xhaust Air System to maintain ODCM limits and remains in standby during normal system ion. It can be lined up to remove gaseous iodine from the exhaust effluent during gaseous effluent releases. The charcoal filter (though not credited in accident analyses) is capable of treating the effluent from ECCS areas served, which have the highest for radioactive contamination. Individual room coolers, in conjunction with the once-through ventilation air, are designed to limit the ambient room temperature to the vital pumping equipment rooms. Maximum allowable ambient temperature in vitn.l pump rooms will not be exceeded assuming a single failure of any individual room cooler or elect.d.cal bus. 'I'he maximum allowable ambient t.emperatures are appropriately cons.i.dered .in the EQ program or other evaluations of equipment temperature tolerance. 9.4-6 SGS-UFSAR Revision 23 October 17, 2007 * *
  • These temperatures help to assure long-term and reliable operation of the pumps, motors,. controls and instrumentation and accessibility to this equipment for maintenance as required. The exhaust fan-filter units in the Auxiliary Building Ventilation System and their controls are designed to seismic Class I criteria. They can be powered from the standby ac power supply during a loss of 9.4-7 SGS-UFSAR Revision 22 May 5, 2006 I offsite power. The distribution ductwork for the is designed to seismic Class II criteria. Room coolers are seismic Class I and from the Standby AC Power System. The seismic design and analysis methodologies used to qualify all ductwork and the contained equipment are described in Section 3.8.4.tJ.l. 'I'he design arrangement of the HEPA and charcoal filter E-)Xhaust units provides various filter.i.ng modes for ventilating the AuxiLi.ary Building cont:inuously ;:md purging the containment interm:Lttontly. In order to purge the containment, standby equipment must be available. The modes of operation are as follows: NORMAL VENTILATION (Normal operations} Normal ventilation is any two of the three exhaust fans and e:l ther of the., two Empply fans. During cooler sea,ons, and with the absence of the system heating coils, i.t may be required to l.imit the amount of colder outside air entering the building. In this case, it is to secure both supply fans from ,..,,..,r.:. .... ,1*ion and reduce the number of operating exhaust fans to one. There is sufficient capacity with the single exhaust fan to maintain the negative pressure within the auxiliary building boundary. EMhiRG8NCY VJ*:N'l'ILA'riON (Emergency Emergency ventila1:ion (emergency plant operations) is any two of the three exhaust fans and either of the two supply fans. During a Safety Injection (SI) all three exhaust fans and one of the fans will start. This is acceptable and wiLl maintain the boundary pressure while supplying the required cooling to the building. Should access/egress become difficult with the three fans running1 one of the exhaust fans should be secured. The accident does not credit HEPA or Carbon fiJ.tration. 9. 4-8 SGS-UFSAR Revision 23 October 17, 2007 * * *
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  • REACTOR SHUTDOWN WITH CONTAINMENT PURGE {Modes 5 & 6) HEPA UNIT 13 (23) CONTAINMENT PURGE EXHAUST in service with HEPA UNIT 11 (21) ECCS and HEPA UNIT 12 {22} NORMAL OR HEPA UNIT 12 (22) CONTAINMENT PURGE EXHAUST in service with HEPA UNIT 11 (21) ECCS and HEPA UNIT 13 (23) NORMAL AND BOTH SUPPLY FANS Some of the Additional Alignments Available (Limited Use) Reactor Shutdown with Containment Purge and Carbon Filtration (Modes 5 & 6) 1. *HEPA UNIT 12 (22) + CARBON UNIT 14 (24) CONTAINMENT PURGE EXHAUST in service with HEPA UNIT 11 (21) ECCS and HEPA UNIT 13 (23} NORMAL 2. *HEPA UNIT 12 (22} + CARBON UNIT 14 (24) NORMAL in service with HEPA UNIT 11 (21) ECCS and HEPA UNIT 13 (23) CONTAINMENT PURGE EXHAUST During Normal Power Operations with 2 filter units and Carbon Filtration 3. 4. *HEPA UNIT 11 (21) + CARBON UNIT 14 (24) ECCS in service with HEPA UNIT 12 (22) NORMAL *HEPA UNIT 12 (22) + CARBON UNIT 14 (24) NORMAL in service with HEPA UNIT 11 (21) ECCS *These alignments utilize the carbon filter bank as a solution to minor airborne contamination problems for ALARA concerns only and are being described here only to present this possible availability. These alignments may introduce airflows that exceed the carbon filter bank flow capacity. Note that in these conditions, the carbon filter bank may not be available for ECCS flowpath filtration . 9.4-Ba SGS-UFSAR Revision 23 October 17, 2007 THIS PAGE INTENTIONALLY LEFT BLANK 9.4-Bb SGS-UFSAR Revision 16 January 31, 1998 9.4.2.2 System Description 9.4.2.2.1 General Description The Auxiliary Building Ventilation System is a once-through heating and ventilating system for each unit, with no connection or sharing between units, except for the drumming and boiling area and the auxiliary building elevator shaft. The Auxiliary Building Ventilation System is shown on Plant Drawings 205237 and 205337. The Control Room and its associated areas are provided with a separate Heating, Ventilating and Air Conditioning System as described in Section 9. 4. 1. Ventilation of the diesel generator area and Fuel Handling Building is described in Sections 9.4.3 and 9.4.5. The post-accident Sampling Room is located in the Unit 2 Auxiliary Building and is served by the Unit 2 Auxiliary Building Ventilation System. A local booster fan is provided for exhausting air from the post-accident Sampling Room. The Auxiliary Building is a multi-level compartmented structure containing the auxiliary nuclear equipment and systems required for the normal, shutdown and emergency modes of unit operation. The Auxiliary Building Ventilation System operates continuously during these modes of operation to perform the following functions: l.Provide satisfactory ambient temperatures within the building. 2. Direct airflow within the building always from the clean areas to the heat producing, contaminated, or potentially contaminated areas. 3.Maintaining the building at a slight negative pressure to control the release of particulate and gaseous contamination from the building in accordance with 10CFR20 limits. 9.4-9 SGS-UFSAR Revision 27 November 25, 2013
4. Purge the Containment Building at selected intervals (shutdown modes only} limited by administrative controls as described in Section 9.4.4.3.1. The Auxiliary Building Ventilation System is comprised of supply and exhaust air systems and a network of individual room coolers. The Supply Air System consists of two 100-percent capacity fan filter units, hot water heating coils, controls, instrumentation and distribution ductwork. The Exhaust Air System consists of three SO-percent capacity fane, three HEPA filter units, one standby charcoal filter unit, controls, instrumentation and distribution ductwork. The room coolers are packaged fan cooler units supplied with service water and mounted locally near vital pumping equipment (residual heat removal, safety injection, compo nent cooling, auxiliary feedwater, charging, and containment spray pumps). Supply air taken from outdoors is delivered primarily to the clean aisles and walkways, although some air is supplied directly to the Residual Beat Removal (RHR) pump pits at the base of the building. Exhaust air is extracted from each room and compartment and delivered to the unit vent alongside the Containment Building. The unit vent effluent is continuously monitored for radioactivity. The room coolers recirculate air around the equipment in the room when required. One branch of the exhaust ductwork is used exclusively for those rooms and compartments that would have the highest potential for radioactivity during a LOCA in the containment (Residual Heat Removal, safety Injection and Charging Pump Rooms; main pipe chase; Spent Resin Rooms; and the containment piping penetration area). The Auxiliary Building Ventilation System continuously maintains the building at a slight negative pressure with respect to outdoors. 9.4-10 SGS-UFSAR Revision 16 January 31, 1998 -
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  • The starting, stopping, and mode controlled from the Control Room. of operation The of the system are manually to this is the pump room which will auto-start on temperatures in their respective pump rooms while in auto position. After being placed in operation, the system automatically maintains building temperature and pressure within satisfactory limits. System and building conditions are monitored from the Control Room. 9.4.2.2.2 System Operation Automatic controls are provided to maintain the building within the design values of pressure and temperature. A temperature switch provides two position modulation of fan capacity from 2/3 airflow capacity to full capacity as the average building temperature varies from 60°F in winter to ll0°F in summer. Simultaneously, a differential pressure controller modulates the exhaust fan capacity between 2/3 and full to maintain the building at a slight negative pressure with to outside. This and pressure control for the Auxiliary Building continues to operate even when containment purging is required . In the event of a LOCA, the Auxiliary Building ventilation equipment continues to operate in its normal mode. That is: 1. One of the two supply air units provides two-position modulation of filtered air to the building in response to building exhaust air temperatures, One (1) supply fan is enabled and one (1) supply fan can be blocked for auto start on receipt of a SEC (LOCA) signal. The blocked supply fan's outside air inlet damper is maintained open. 2. Two of the three HEPA filter units and exhaust fans operate while fan inlet guide vanes continuously modulate flow in response to building negative pressure . 9. 4-11 SGS-UFSAR Revision 23 October 17, 2007 The following occur automatically: 1. Room coolers will start automatically and operate continuously at full capac:L ty in response to the above normal ambient temperatures that develop as the containment spray 1 charging 1 safety inj eel ion, cooling, and auxiLiary feedwater pumps are ::;tarted. However, in the event that vital power is by diesel the room coolers for the RHR charging, and containment spray pumps may be delayed for up to 20 minutes. 2. Containment purging is terminated. Thereafter, operator action is required i.f troubJe or failure alarms sound in the Control Room: 1. The standby supply air unit can be energi.ZE:ld if the operating unit signals low air flow, high or low supply a:i.r temperature, or a break in the hot water heating co;ll. 2. The standby HE:Pl\ filter exhaust unit can be placed in service if either of the other two operating units experience high differential pressure. 3. The standby exhaust fan can be energized if either of the two opm:*ating fans experience an operational problem. il. 'l'he loss of power fail-safe damper positions ensure one HEPA filter exhaust unit and charcoal .ftJ.ter unit are available for the ECCS equipment areas. 'I'he remainder of the Auxiliary Building areas are exhausted through the HEPA fiJ.ter unit to the Unit vent without through the charcoal filter unit. 9.4-12 SGS-OF'SAR Revision 23 October 17, 2007 * * *
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  • The damper at the outlet of the charcoal filter consists of two operating sections, each with an operator. Damper blades are designed to go to the full open position in the event that control air or electric control power is lost. Manual control air bypass valves are available near the charcoal filter unit damper operator in the event the single solenoid valve for the two damper sections experiences a mechanical failure. In addition, each damper section can be manually positioned locally to the required position. 9.4.2.3 The Auxiliary Building Ventilation System can maintain design conditions in the Auxiliary Building with one of the two 100-percent capacity fan-filter supply air units, two of the three 50-percent capacity exhaust fans, and two of the three HEPA filter exhaust air units operating. The charcoal filter exhaust air unit is normally in standby. Exhaust fans take suction from a common plenum at the outlet side of the HEPA and charcoal filter units, which permits changes in the exhaust filter operating mode without affecting fan operation. The system is normally operated from the Control Room. Supply air to the Auxiliary Building and to the containment is filtered by high efficiency filters. This high quality filtration significantly reduces the inventory of that could become contaminated and lessens the loading on the more vital exhaust air filters. All exhaust air from the Auxiliary Building and Containment (during purge operation) is processed through HEPA filters which remove at least 99 percent of all particles 0. 3 micron and larger in size. In the event of a LOCA, no change is required in the operating mode in effect for the Auxiliary Building. If there is indication of excessive radiation levels in the Auxiliary Building, the charcoal filter can be aligned to the ECCS flowpath through either 11 (21) HEPA or 12 (22) HEPA units as required. The HEPA and charcoal filters are credited to control releases to ODCM limits and are not credited in the Chapter 15 accident dose analysis . 9.4-13 SGS-UFSAR Revision 23 October 17, 2007 During any LOCA, the room coolers for pwapa liated in Section 9.4.2.1 are automatically energized (the fan motor starts and a service water supply valve opens in response to increasing temperatures) to operate at full capacity continuously. In the event that the temperature in a pump room exceeds its specified upper limit, an alarm is sounded in the Control Room. In general, ventilation air is supplied to the areas having the least potential for contamination and exhausted from the areas of potentially higher contamination. The Auxiliary Building is designed to be at a alight negative pressure continuously with respect to the outdoors. These design considerations satisfy the basic criterion for preventing the uncontrolled release of radioactivity. standby fan and filter capacity is included in the Auxiliary Building Ventilation system to assure that the design pressure, temperatures and air flow patterns for the building are controlled continuously during maintenance or testing. The system components subject to single failure have been reviewed for impact on system capabilities to perform ita design basis function. Where identified deficiencies exist, engineering evaluations have been performed that support the required system performance level. Filtration of the supply air from outdoors is designed to minimize the inventory 1 of airborne particulates within the 9.4-14 SGS-UFSAR Revision 16 January 31, 1998 *-*-
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  • Auxiliary Building and the containment. This reduces the potential hazard of irradiated particles being transported throughout the building and reduces the loading on the exhaust filters. The HEPA type exhaust filters, in continuously minimize the release of particulate radioactivity to the environment while the St(;!ndby ch.arcoal filter is available to adsorb gaseous contamination. The design capability of a three-part high level filtration train ensures that all exhausted emissions from the Auxiliary Building and the containment are within the requirements of 10CFR20. Availability of the Auxiliary Building supply and exhaust ventilation equipment is ensured by connection to the standby ac power supply. The room coolers located near v'i tal pumping equipment are single units. The total capacity of the room cooler(s} in a given area, in conjunction with the exhaust air flow rate-, is designed to limit the area temperature to the design values .even if all pumping equipment in the area is operated contiiluously. In the event that the Safety Injection Pump Room cooler fails concurrent with operatiqn of both SI pumps, temperature in the SI Pump Room may exceed 120°F. Equipment .in this area will operate at temperatures to 146"F. Similarly, in the event that the 12 (22) Component Cooling Water (CCW) Room Cooler fails concurrent with operation of both CCW pumps in the room, temperatures in the 12 (22) .CCW Heat Exchanger and Pump Room may exceed 120°F. Equipment in this area will operate at temperatures to 132"F. 9.4.2.4 Test and Inspections All components o.f the Auxiliary Building Ventila*t.ion System are subjected to a test and inspection program. This program is_ similar to that described for the Containment Ventilation System 9. 4. 4), except the resistance to LOCA pressure and temperature transients is not applicable to the Auxiliary equipment. The Auxiliary Building exhaust air filtration system shall be demonstrated functional: a. At least once per 31 days by initiating, from the control room, flow through the HEPA filter and charcoal adsorber train and verifying that the.fiJ,ter tJ;i:.\in.and_eC;l.ch fan.::..operate for at least. 15. minutes . 9.4-15 SGS-UFSAR Revision 23 October 17, 2007
b. c. At least once per 18 months or (1) after any structural maintenance on the HEPA filter or charcoal adsorber housings, or (2} painting, fire or chemical release in any ventilation zone communicating with the system, by: 1. Verifying that with the system operating at a flow rate of 21,400 cfm +/- 10 % and exhausting through the HEPA filters and charcoal adsorber.s, the total bypass flow of the ventilation system to the vent, including leakage through the ventilation system diverting valves, is S 1% when the is tested by admitting cold DOP at the system intake. 2. Verifying that the charcoal adsorbers remove 99% of a halogenated hydrocarbon refrigerant test gas and that the HEPA fj.lter banks 99' of the DOP when they are tested [For Unit 2: using the test procedure guidance of Regulatory Positions C.5.a1 C.S.c and C.5.d of Regulatory Guide 1.52, Revision 21 March 1978 (except for the provisions of ANSI N5J.O Sections 8 and 9)] and the system flow rate is 21,400 cfm +/- 10%. 3. Veri within 31 days after removal from *the 1\BV unit, that a laboratory test of a sample of the charcoal adsorber, when obtained in accordance with Regulatory Position C.6.b of Regulatory Guide 1.52, Revision 2, March 1978, shows the methyl iodide penetration less than 15.0% when tested in accordance with ASTM 03803-1989 at a temperature of 30° at a nominal face velocity of 74 ft/min, and a relative humidity of 95%. 4. Verifying a system flow rate of 21,400 cfm +/- 10% during system operation. [For Unit 2: VerJfy that the system flowrate does not exceed the design limit of 23,540 cfm (21,400 cfm + 10%) when the HEPA + Charcoal adsorber filter train is aligned to the E:CCS equipment areas.] After every 720 hours0.00833 days <br />0.2 hours <br />0.00119 weeks <br />2.7396e-4 months <br /> of charcoal adsorber operation by verifying within 31 days after removal from the ABV unit, that a laboratory analysis of a carbon sample, when obtained in accordance with Regulatory Position C.6.b of Regulatory Guide 1. Revision 2, March 1978, shows a methyl iodide penetration less than 15.0% when tested in accordance with AS'I'M D3803-1989 at a temperature of 30°C, at a nominal face velocity of 74 ft/min, and a relative humidity of 95%. d. At least once per 18 months by: 1. Verifying that the pressure drop across the combined HEPA filters and charcoal adsor.ber banks is < 4 inches Water Gauge while operating the ventilation at a f.low rate of 21,400 cfm +/- 10%. 2. For Unit 1 only: Verifying that the air flow distribution is uniform within 20% across HEPA filters and charcoal adsorbers. e. After each complete or parU.al replacement of a HEPA filter bank by verifying that the HEPA filter banks remove 2: 99% of the DOP when they are tested in-place while operating the ventilation system at a flow rate of 21,400 cfm +/- 10%. f. After each complete or partial replacement of a charcoal adsorber bank by verj.fying that the charcoal adsorbers remove 2: 99% of a hydrocarbon test gas when they are tested in-place while operatj.ng the ventilation system at a flow rate of 21,400 cfm +/- 10% . 9.4-15a SGS-UFSAR Revision 23 October 17, 2007 * * *
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  • SGS-UFSAR This page left intentionally blank 9.4-15b Revision 23 October 17, 2007 9.4.3 Fuel Handling Area Ventilation 9.4.3.1 Design Bases The Ventilation System is designed to exhaust the spent fuel pool area at 60 air changes an hour within a 10-foot height above the pool during design conditions for spent fuel storage. Out of a system operating capacity of 20,000 cfm, 15,000 cfm is exhausted from the spent fuel pool area (10,000 of which is extracted right at the pool surface) and the remaining 5,000 cfm of system capacity ventilates other parts of the building. Because of the potential for radioactive releases from the spent fuel, defective fuel cladding or a fuel handling mishap, the building is maintained at a slight negative pressure to assure inleakage of air rather than outleakage. The total capacity of the Ventilation System, along with the area space heaters, is designed to maintain the building between 60°F and 105°F. The space heaters are not safety-related, do not receive Class lE power, and would not be available during a loss of offsite power. An evaluation of the Fuel Handling Building has justified a minimum temperature of 4 0°F. Although there is no direct control of the humidity in the building and there can be instances of 100-percent relative humidity around the spent fuel pool when the outdoor air is damp, the relative humidity under design conditions is expected to be less than 70 percent. The exhaust filter units, fans and controls are designed to Class I (seismic) criteria. The discharge ductwork from the fuel handling area to the plant vent is also designed to Class I (seismic) criteria. The supply air equipment is served by the Normal AC Power System only, whereas the exhaust air equipment can be energized from the Standby AC Power System in the event of a loss of offsite power,* The seismic design and analysis methodologies used to qualify all ductwork and the contained equipment are described in Section 3.8.4.4.1. 9.4-16 SGS-UFSAR Revision 20 May 6, 2003 9.4.3.2 System Description 9.4.3.2.1 General Description The fuel handling area is a structure separate from other unit structures and is provided with its own ventilation system. This system is a once-through filtered air system that continuously ventilates the normal operating areas (fuel pools, decontamination pit, electrical equipment room and sump tunnel). The Fuel Handling Area Ventilation System is shown on Plant Drawings 205321 and 205322. The Ventilation System consists of the following equipment: 1. One 100-percent capacity supply air unit with particulate filters at about SO-percent cleaning efficiency and a heating coil for winter-time tempering of the supply air 2. Two 50-percent capacity exhaust fans 3. One 100-percent capacity HEPA filter exhaust unit and one 100-percent capacity HEPA and charcoal filter exhaust unit available for standby 4. Controls and instrumentation 5. Distribution ductwork 6. Pressure relief damper All exhaust effluent is diverted to the standby HEPA and charcoal exhaust unit in the event that radioactivity levels within the building become excessive. This exhaust effluent path through the HEPA and charcoal filters is not credited in the Fuel Handling Accident in the Fuel Handling Building. Control of the system and surveillance of building conditions are accomplished from the Control Room. 9.4-17 SGS-UFSAR Revision 27 November 25, 2013 Air is distributed with overhead ducts for supply and exhaust, as well as embedded exhaust ducts around the spent fuel pool. Supply air enters the building at the cask storage area, flows through the to the spent fuel pool area, and is exhausted to the unit vent where the total plant effluent is continually monitored for radioactivity. Supply air may also enter through the pressure relief intake dampers at the truck bay when the supply fan is shutdown and only one exhaust fan is running. The Ventilation System maintains the building under a slight negative pressure and exhausts the heat and humidity emitted from the spent fuel pool. 9.4.3.2.2 System Operation Normally the air unit1 both exhaust fans and the HEPA exhaust filter unit operate continuously. The supply air unit operates at a constant volume. Exhaust air is varied through inlet guide vanes on each exhaust fan which are controlled by a differential pressure controller to maintain a negative pressure of approximately 0.125 inch water gage in the building. If the inside building temperature decreases to the minimum 60°F, the heating coil and controls at the supply air unit are energized and, together with the area space heaters, maintain the building at or than 60°F, even if the supply air inlet should decrease to the minimum outside 0°F temperature, as could occur during winter conditions. Because the space heaters are not safety-related and do not receive Class lE power, as during a loss of offsite power event, the minimum design temperature has been evaluated permitting temperature to decrease to 40°F. In the event that a local radiation monitor detects excessive radioactivity in the building and alarms in the Control Room, the operator can divert the building effluent from the HEPA exhaust unit to the standby HEPA and charcoal exhaust unit. Also during the event, an automatic initiation of the exhaust fans will take place for Unit 2. Additional alarms in the Control Room will signal adverse operating conditions: low or high supply air temperature, low air flow from the supply or exhaust clogged HEPA filters, and insufficient negative pressure in the building. 9.4.3.3 The heating and ventilating of the fuel handling area is based on outdoor design conditions of 0°F in winter, 93°F dry bulb and 79°F wet bulb in summer. These values satisfy 99 percent of the 9.4-18 SGS-OFSAR Revision 22 May 5, 2006 weather conditions experienced annually at the Salem site and offer a high degree of assurance that satisfactory temperature conditions will be maintained. Directing the air flow from areas of least contamination to areas of higher contamination is accomplished in two ways. First, the building is maintained at a negative pressure such that outdoor air leaks into the building rather than building air leaking out. Secondly, air flow within the building is from the cask storage area to the spent fuel pool area. Efficient filtration of the supply air minimizes the inventory of airborne particulates within the building. This reduces the rate of dirt buildup on the HEPA filter exhaust units and extends their useful life. Whereas the supply air filters can be replaced easily and safely as required, the HEPA exhaust filters are potentially radioactive and less maintenance is desirable. The heat, humidity and potential radioactivity in the building is confined to the spent fuel pool area. Seventy-five percent of the building exhaust occurs in that area, and the 60 air changes per hour over the pool is a rapid exhaust rate. Two-'thirds of this exhaust rate takes place just inches above the pool water through numerous, high velocity (2000 fpm) exhaust ports spaced around the pool periphery. These ports act to vacuum the surface of the pool and effect early capture of pool emissions. The exhaust portion of the Fuel Handling Area Ventilation System includes one filtration unit containing only roughing and HEPA filters, and one filtration unit containing roughing and HEPA filters, and carbon absorbers. There are two (2) 50% capacity exhaust fans and one (1) 100% capacity supply fan. The charcoal filter train is normally at standby and is inspected and tested periodically for availability, especially prior to refueling. This administrative control will assure the preparedness of the filter train and clogging of the train during the relatively short period of refueling or during a fuel handling accident is not anticipated. The Fuel Handling Accident in the Fuel Handling Building was analyzed without credit for filtration by the Fuel Handling Building Ventilation System. 9.4-19 SGS-UFSAR Revision 22 May 51 2006 I (Historical Information) Overheating of the carbon filters from radioiodine loading is not expected to occur. An analysis was performed using Safety Guide No. 25 assumptions assuming all the airborne radioiodine released during a design basis fuel handling accident wc1s adsorbed on the charcoa1 fi 1 ters. The .resulting heat generation rate is negligible (less than 100 Btu/hr) compared to the heat Y"'"'OlLa rate required to through the filters) to the (greater than 100,000 Btu/hr). elevate the point that carbon temperature {with airflow de-adsorption or ignition occurs 'l'he exhaust ductwork and exhaust fan-filter units leading from the fuel handling structure to the plant vent are seismic Class I des:i9n. Exposed ductwork alon9 the walls within the structure is seismic Class II. 'rhe supply air unit, located below the fuel handling operating floor, is of non-seismic standard constructl.on. 'J'he seismic design and analysis methodologies used to qualify all ductwm:*k and the contained equipment are described is Section 3.8.4.4.1. In the event of a seismic disturbance or a fuel handling accident that causes the failure of non-Class I equipment, the primary function of tbe Ventilation System will still be maintained. That is, the seismic Class I portion of the exhaust will continue to operate, creating a negative pressure within the structure, and pass the exhaust through HEPA and charcoal filters. 'I'here would be no increase in building differential pressure and, therefore, radioactivity would be contained within the building. A gravity pressure relief damper and a manual volume damper are provided in the exte.d.or wall of the shipping bay. 9. 4. 3. 4 All components of the F'uel Handling Area Ventilation System are subjected to a program of tests and inspections. 'l'his program is similar to that described for the Containment Ventilation System (Section 9.4.4.4) except that resistance to LOCA pressure and temperature transients is not applicable to the fuel handli.ng area. 9.4-20 SGS-lJFSAR Revision 23 October 17, 2007 * *
  • 9.4.4 Containment Ventilation System 9.4.4.1 Design Bases Containment ventilation is subdivided into a number of independently controlled systems which perform specific functions for the containment during normal power generation, the design basis LOCA and a loss of offsi te power. The systems are the following: 1. Containment Fan Cooler System 2. Containment Iodine Removal System 3. Rod Drive Ventilation System 4. Reactor Nozzle Support Ventilation System 5. Reactor Shield Ventilation System 6. Pressure -Vacuum Relief System 7. Containment Purge System The containment ventilation flow diagram is shown on Plant Drawings 205238 and 205338. Except for the Pressure-Vacuum Relief System and the Containment Purge System, both of which connect the containment atmosphere to the environment at controlled intervals, all systems are of the recirculation type, completely contained within the containment, which have sufficient redundancy to perform their required functions. 9.4-21 SGS-UFSAR Revision 27 November 25, 2013 9.4.4.1.1 Containment Fan Cooler System The Containment Fan Cooler System is an engineered safeguard that is designed to during normal power generation and "blackout" situations as well as during the design basis LOCA. The system is described in detail in Section 6.2.2.2. This system removes heat from the containment atmosphere to limit the average temperature to 120°F during normal power operation, shutdown conditions and "blackout" situations. 9.4.4.1.2 Containment Iodine Removal System (Internal Cleanup) Two iodine removal units are provided within the containment. Each unit is designed to remove gaseous iodine and particulate radioactivity from the containment atmosphere as required to minimize airborne activity concentrations for containment access during normal operation. 9.4.4.1.3 Rod Drive Ventilation System Three one-half capacity ventilation fans remove heat continuously from the control rod drive mechanisms during normal power operation, The air flow rate generated by the two operating fans is sufficient to maintain a satisfactory ambient temperature around the electromagnetic positioning coils of the rod drive mechanisms. 9.4.4.1.4 Reactor Nozzle Support Ventilation System The four reactor nozzle supports are cooled by two sets of two fans. Each pair of full capacity fans cools two of the four nozzle supports. This system operates during normal power operation to assure that concrete surfaces in contact with the structural steel supports do not exceed the design temperature of 150°F. The fans are powered from the Standby AC Power System to cool the concrete during a loss of offsite power. 9.4-22 SGS-UFSAR Revision 22 May 5, 2006 9.4.4.1.5 Reactor Shield Ventilation System Two 100-percent capacity fans provide continuous ventilation for the reactor cavity to assure that the ambient temperature within the shield and around the neutron monitoring instrumentation cables does not exceed the design value of 135°F during normal power operation. The fans are powered from the Standby AC Power System to provide reactor cavity cooling during a loss of offsite power. The air delivered by the Reactor Shield Ventilation System is exhausted primarily through the Reactor Nozzle Support Ventilation System, with the balance of the air forced up and out of the cavity. 9.4.4.1.6 Pressure-Vacuum Relief System The Pressure-Vacuum Relief System is a normally isolated system which can be used during power and hot standby operations as required to maintain containment pressure in the range of -1.5 to +0.3 psig. One exhaust effluent filter unit and one supply air filter unit are connected to a common penetration to relieve containment pressure or vacuum during normal power operation. The supply air filter unit can be manually energized in the event of a negative pressure in the containment. The exhaust filter unit can be manually energized for pressure relief if the containment pressure exceeds the ambient pressure. All exhaust is directed to the plant vent where it is monitored to assure that releases to the environment are within the limits specified in 10CFR20. The design pressure differentials inherently provide the motive power to restore the containment to an equilibrium pressure. Therefore, no fan power is provided in the system. 9.4.4.1.7 Containment Purge System The Containment Purge System is normally isolated. One supply air penetration and one exhaust penetration are provided for purging 9.4-23 SGS-UFSAR Revision 6 February 15, 1987 the containment atmosphere during normal plant shutdown. Purging refreshes the containment within as required to maintain doses to operating personnel limits during shutdown maintenance and/or inspections. All exhaust is directed to the plant vent where it is monitored to assure that rel.t'!ases pair of 1\u:x:Hiary to the environment are within the limits specified in 10CFR20. One supply and exhaust fans and filters is normally available in the Building Ventilation System to the containment purging functions. 9. 4. 2 9.4.4.2.1 Fan Cooler Units The information is in Section 6.2.2.2. 9.4.4.2.2 Containment System 'The Containment Purge System is a normally closed, deactivated system that is manually energized as required to perform the functions described in Section 9. 4. 4. 1. 'l'he supply and exhaust air equipment used for. the various purging modes are the standby fan and filter units insta1led in the Auxiliary Building Ventilation System. Purging air is supplied by one 35,000-cfm unit consisting of fan and motor, hot water heating coil, 80-percent efficiency filters, shutoff dampers, controls and instrumentation, and a supply duct. 9.4-24 SGS-UFSAR Revision 23 October 17, 2007 * *
  • The heating coil is designed to temper the air during winter to 60°F maximum. A low limit temperature alarm is provided in the Control Room to alert the operator in the event the supply air temperature approaches the freezing point. A pneumatically operated, quick-closing, butterfly-type isolation valve is installed outside the containment wall. The valve is designed to withstand the 47 psig, 271°F atmosphere following a design basis LOCA and to close automatically on a safety injection signal or on a high radiation signal from the radiation monitoring devices discussed in Section 11. The filters remove most of the atmospheric dust and dirt that would otherwise enter the containment. Purging air is exhausted by energizing the 35,000-cfm capacity standby exhaust fan and a standby HEPA filter which are normally available in the Auxiliary Building Ventilation System. Operation of the standby fan in addition to two other exhaust fans provides the dual capability of purging the containment and exhausting the Auxiliary Building. The output of each exhaust fan is controlled such that the rate of containment purging can be varied from 0. 57 to 0. 80 air changes per hour as required, while maintaining the Auxiliary Building at design conditions. The HEPA filters remove 99 percent of particles 0.3 micron and larger from the containment exhaust and are preceded by roughing filters to prolong the life of the HEPA filters. A 24,000-cfm capacity charcoal filter unit on standby in the Auxiliary Building Ventilation System can be placed in series with the containment purging HEPA filter exhaust unit. The charcoal filter is designed to absorb gaseous contaminants, particularly iodine, and when in use will afford a purging rate of 0. 57 air changes per hour. During a reactor shutdown period when a different HEPA filter exhaust unit is available in the Auxiliary Building System for containment purging, but without the charcoal filter, the purging rate can be increased to 0.80 air changes per hour. 9.4-25 SGS-UFSAR Revision 24 May 11, 2009 The purging exhaust duct that penetrates the containment is provided with an isolation valve as described previously in this section for the purging supply duct. The exhaust air is combined with the Auxiliary Building exhaust air and directed to the plant vent where the total flow is monitored for radiation. All penetrations, exhaust equipment, and exhaust ductwork are designed to Class I (seismic) criteria. All supply equipment and supply ductwork are Class II (seismic) design. Purging system compliance with Branch Technical Position (BTP) CSB 6-4 is discussed in Section 9.4.4.3.2. The seismic design and analysis methodologies used to qualify all ductwork and the contained equipment are described in Section 3.8.4.4.1. 9.4.4.2.3 Pressure-Vacuum Relief System The Pressure-Vacuum Relief System is a normally closed deactivated system that is manually energized as required to equalize the containment with outdoor pressure during normal power operation. The system is designed for 2400 cfm The exhaust air relief) filter unit consists of roughing, HEI?A and charcoal filters, shutoff dampers, backdraft Protection System for the charcoal filters. and a water spray Fire The HEPA filters are designed to collect not less than 99 percent of particles 0. 3 micron and larger, while the charcoal filters are designed to absorb not less than 90 percent of gaseous iodine. The supply air (vacuum relief) filter unit consists of 80-percent efficiency filters, shutoff damper and a backdraft preventer. The filters remove most of the atmospheric dust and dirt that would otherwise enter the containment. 9.4-26 SGS-UFSAR Revision 24 May 11, 2009 The common duct from the containment to the supply and exhaust air filter units is provided with two isolation valves in series, one on each side of the containment wall. The supply air filter unit is of standard construction. The exhaust air unit and all ductwork are designed and constructed to seismic Class I criteria. Pressure-Vacuum Relief System compliance with BTP CSB 6-4 is discussed in Section 9. 4. 4. 3. 2. The seismic design and analysis methodologies used to qualify all ductwork and the contained equipment are described in Section 3.8.4.4.1. 9.4.4.2.4 Containment Iodine Removal System (Internal Cleanup) The Containment Iodine Removal System consists of two fan and filter units located on Elevation 100 feet of the containment building outside the polar crane wall. Either of the units can be manually energized depending upon the need to reduce the level of particulate and gaseous radioactivity. The level of activity within the containment can be continually monitored by gaseous and particulate air monitors. design basis LOCA. Neither unit is required to be operated during a Each 8,000-cfm capacity iodine removal unit is comprised of a single speed fan, roughing, HEPA and charcoal filters, shutoff dampers, and a water spray Fire Protection System for the charcoal filters. The HEPA filters are designed to collect 99 percent of particles 0. 3 micron and larger, while the charcoal filters are designed to adsorb 90 percent of the gaseous iodine. Source air to each iodine removal unit is supplied through a duct connected to the large duct header of the Fan Cooler System. All equipment and materials comprising the Containment Iodine Removal System are designed and constructed to satisfy Class II seismic criteria. The seismic design and analysis methodologies used to qualify all ductwork and the contained equipment are described in Section 3.8.4.4.1. 9.4.4.2.5 Control Rod Drive Cooling Control rod drive cooling is performed by the Rod Drive Ventilation System, which consists of three one-half capacity fans 9.4-27 SGS-UFSAR Revision 22 May 5, 2006 connected to the Control Rod Drive Ventilation System ducts which are integral to the Integrated Head Assembly (IHA). The CRDM ventilation system fans are located on the IHA above the missile shield. Two of the three 34,500 acfm (@ 120°F) fans operate during normal power operation to remove 2. 6 x 106 Btu/hr from the control rod drive mechanism and discharge the heat above the operating floor (approximate Elevation 130 feet). This heat is then removed from the containment by the cooling coils in the Fan Cooler System. 9.4.4.2.6 Reactor Vessel Cooling Cooling of the reactor vessel is performed by the Reactor Shield Ventilation System in conjunction with the Reactor Nozzle Support Ventilation System. Both systems can be powered by the Standby AC Power System, and are designed to Class II seismic criteria. The seismic design and analysis methodologies used to qualify all ductwork and the contained equipment are described in Section 3.8.4.4.1. The Reactor Shield Ventilation System consists of two 100-percent capacity 18, 000-cfm fans located outside the polar crane wall at Elevation 100 feet, each with its own duct system. The fans draw filtered, cooled air from the large duct header of the fan cooler system and deliver it to the neutron monitoring instrumentation cable space under the reactor. The system is designed to maintain the cable space at 135°F or less, provide 16, 000 cfm through the annular space around the reactor to the Reactor Nozzle Support Ventilation System, and provide 2,000 cfm upward to the reactor head. The Reactor Nozzle Support Ventilation System consists of two identical subsystems, each comprised of two 8, 000-cfm fans (one spare) connected to common ductwork embedded in the reactor shield to cool two of the four reactor nozzle supports. The system draws air from the annular space around the reactor and through each of the nozzle supports to maintain the concrete bearing surfaces at 9.4-28 SGS-UFSAR Revision 22 May 5, 2006 150°F or less. Source air is supplied to the annulus by the Reactor Shield Ventilation System. All fans are located outside the reactor shield on floor Elevation 81 feet and discharge in the vicinity of the steam generators. 9.4.4.2.7 Penetrations Ventilation duct penetrations in the Containment Building are equipped with pneumatically operated, quick closing, butterfly-type isolation valves. Each isolation valve is part of a sealed assembly, designed to Class I seismic criteria, to withstand the 47 psig, 271°F, saturated steam-air mixture resulting from a design basis LOCA. Complete closure of at least one valve at each penetration satisfies containment isolation or closure criteria. The seismic design and analysis methodologies used to qualify all ductwork and the contained equipment are described in Section 3.8.4.4.1. All ventilation isolation valves that remote-manual actuation to open are of the fail-closed type. The valve operator is a dual acting (except for the pressure-vacuum relief valves, which are single acting/spring return), piston-type, pneumatic operator, controlled by a solenoid-type air supply valve. In the event of a loss of control air pressure and/or electric control power, a spring assembly integral with each isolation valve is designed to, return the valve to the closed position. Each ventilation isolation valve is equipped with a permanently bonded rubber seat (except 1VC5 and 1VC6 which have hard metal seats) for the butterfly disc, and low leakage bushings on the butterfly shaft. This construction limits leakage from each valve to 5. 0 cc per hour per inch of valve diameter when subjected to 47 psig saturated steam in the closed position. 9.4.4.2.8 Instrumentation and Control Instrumentation and controls for starting, stopping and monitoring the of the Containment Ventilation System are located 9. 4-29 SGS-UFSAR Revision 24 May 11, 2009 I in the Control Room. Additional instrumentation is also provided locally for inspection, test and maintenance. The instrumentation and controls provided in the Control Room include the following: 1. START and STOP pushbuttons for fans and fan coolers. 2. Low air flow alarms. 3. OPEN-CLOSE indication for the (The normal positioning of the of the fan at its higher air control dampers in each fan cooler. dampers is interlocked with the starting while the post-accident positioning of the dampers and the lower fan injection signal.) are interlocked with a 4. High differential air pressure alarms for filters. 5. High temperature alarms for the fan cooler motor bearings and windings, air leaving each fan cooler, air discharged from the control rod drive mechanisms and reactor nozzle supports, ambient air around the neutron monitoring instrumentation cables, and the ambient air at numerous locations throughout the containment. 6. Control equipment to manually select ventilation filtration service water isolation valve position indicating lights. duct isolation valves are interlocked to close automatically on a safety injection signal or in the event of a high radiation signal from the containment. 7. Service water temperature and flow indication. 9.4-30 SGS-UFSAR Revision 24 May 11, 2009
8. Fire alarms to signal any ignition of a charcoal filter bank. (The ignition detection automatically actuates a water deluge system for the affected charcoal filter.) 9. High_ radiation alarms for service water leaving the fan coolers. These monitors are located outside the containment;. 10. An overhead annunciator alarm is received whenever containment ventilation isolation is reset in the presence of an isolation actuation signal. The instrumentation provided locally includes the following: 1. Manometers for indication of pressure drop across each bank of HEPA and charcoal filters, and each bank of roughing filters outside the containment. 2. Position indicators for each air control damper, water control valve, and isolation valve. 3. Pressure test-taps or gages in service water lines to each water cooled fan motor in the Fan Cooler Safeguard System. 9.4.4.3 Design Evaluation 9.4.4.3.1 General During the final design review of Unit 2 the Nuclear Regulatory Commission requested verification that adequate torque was available to shut isolation valves in the Containment Vacuum Relief and Purge System. Public Service Electric & Gas evaluated this matter based on a conservatively assumed differential pressure of 60 psi, and it was determined that the actuator torque values were not sufficient to move the valves from the full open (90°) position to the closed position (O*). With a differential 9.4-31 SGS-UFSAR Revision 6 February 15, 1987 pressure of between 18 to 24 psi, which is the calculated actual differential, the actuator torque values were marginal. Corrective action was therefore taken as follows: 1. For the 36-inch purge valves, controls were implemented to keep the valves closed 1.n all operating modes except shutdown and refueling. 2. The 10-inch valves were modified by the vendor. The modification consisted of reworking the actuator and a realignment of the actuator and valve shaft such that the full open position will correspond to 60° open instead of the original 90* open. This significantly reduced the required closing torque with a 60 psi differential to a value well below the available actuator torque. The new required closing torque with a 60 psi differential is 4,572 in-lbs, whereas the actuator torque available is 9,100 in-lbs, (spring force only, with no air assist). Detailed valve information is contained in correspondence dated February 18, 1982 (Liden to Varga). The Containment Fan Cooler System is required to remove Heat from the containment atmosphere to limit the average containment temperature during normal operation within design limits. A maximum of four out of the five units installed operate in high speed to recirculate, filter and cool the containment atmosphere during normal operation. Additional evaluation is presented in Section 6.2.2.2. The design of all the other mechanical Ventilation Systems within the containment (iodine removal, reactor shield ventilation, reactor nozzle support ventilation, and control rod drive ventilation) includes at least one standby unit with its own power, controls and instrumentation. Physical separation and redundancy of the power and control sources enhances the 9.4-32 SGS-UFSAR Revision 12 July 22, 1992 reliability of these systems. The failure of a single component or unit, will not prevent these systems from performing their design therefore, function. Additionally, the design operating capacity of the Reactor Shield, Reactor Nozzle, and Rod Drive Ventilation Systems exceeds the minimum performance requirements. Ventilation ductwork penetrating the containment consists of two 36-inch diameter ducts for containment purging and one 10-inch diameter duct for containment pressure-vacuum relief. Isolation valves in each duct, at each containment penetration, assure valve closure to prevent the release of radioactivity from the containment environment. Each of the isolation valves is designed to withstand the effects of any LOCA accident. Failure of a single component or unit will not prevent these isolation valves from performing their function. The control rod drive mechanism (CRDM), reactor vessel supports and the out-of-core nuclear instrumentation are provided systems. cooling air by the separate, independently controlled ventilation They are Rod Drive Ventilation System (Section 9.4.4.2.5), Reactor Nozzle Support Ventilation System and the Reactor Shield Ventilation System (Section 9.4.4.2.6) Loss of cooling air to the CRDMs, the vessel supports, or the nuclear instrumentation will be detected via high air temperature alarms and/or low air flow alarms for the respective ventilation systems serving this equipment. Temperature and flow instrumentation is provided for each of the Ventilation Systems as shown on Plant Drawings 205238 and 205338. An alarm is annunciated in the Control Room on indication of low airflow or high air temperature for an individual vent fan unit of the Ventilation Systems. The operation of the vent fan units (start-stop) is also monitored in the Control Room. The CRDM coils have a design operating temperature of 392°F. Should this temperature be exceeded over a period of time, the 9.4-33 SGS-UFSAR Revision 27 November 25, 2013 life of the mechanism coils would be affected. The reactor vessel support concrete surfaces have a design operating temperature of 150°F. The out-of-core nuclear instrumentation and cabling have a design operating temperature of The Containment Ventilation Systems have been designed with spare capacity fans, physical separation, and redundant power and control sources so that a single component or unit failure will not affect the operation of these systems and ensure that these design temperatures are not exceeded. An average ambient temperature of 120°F in the containment is maintained by the containment fan coolers. Under normal conditions, two of the three rod drive vent fans operating will maintain the temperature of the CRDM coils below 392°F and the CRDM ventilation fan outlet temperature below 160°F. The reactor vessel supports will have sufficient cooling air from two of the four reactor nozzle support fans (one from each pair) so that the design temperature of 150°F is not exceeded. The operation of one of the two reactor shield vent fans will keep the out-of-core instrumentation below the design operating temperature of 135°F. The temperature alarms will annunciate when the normal operating temperatures are exceeded. The Ventilation System alarms will warn the operator if the cooling air for the CRDMs, reactor vessel supports, or the out-of-core instrumentation areas has exceeded the temperature limits or do not have sufficient cooling air flow. The operator will then manually actuate the spare fan units for the affected system. These actions should restore normal cooling air flow and temperatures to the above-mentioned equipment and areas and return the alarmed condition to normal. It is considered highly unlikely that a complete loss of cooling air from the Containment Ventilation Systems would occur because of the system design and use of multiple fans. In the unlikely event that high temperature and/or low air flow alarms are annunciated and the spare capacity fans and coolers are incapable of supplying the required ventilation to maintain design 9.4-34 SGS-UFSAR Revision 22 May 5, 2006 conditions, the plant will be shut down to prevent equipment damage and to effect repairs to the ventilation systems. 9.4.4.3.2 conformance to Branch Technical Position css 6-4 This section addresses conformance of Containment Purge and the Pressure-Vacuum Relief systems to BTP CSB 6-4. The item numbers below correspond to the numbering used in section 5 of CSB 6-4: la. The purge line isolation valves were purchased, manufactured and factory tested prior to the issuance of the NRC BTP MEB-2, "Pump and Valve Operability Assurance Program." The pressure-vacuum relief line isolation valves have been replaced and meet the intent of NRC BTP MEB-2. The appropriate design, environmental and leakage parameters were adequately specified for these isolation valves. The valves have undergone testing to verify leak tightness and operability during seismic events. for the valves. operability and Specifications. The appropriate quality documentation was provided The valves will be tested periodically for leakage in accordance with the Technical Although not specifically referenced, the design and testing of the purge and pressure-vacuum relief isolation valves meet the intent of BTP CSB 6-4. lb. Each unit has two purge lines and one pressure-vacuum relief line penetrating the containment. lc. The purge vent lines are 36 inches in diameter and the pressure-vacuum relief line is 10 inches in diameter. The 36-inch lines, however, are not used for routine station operation. The operability of the 10-inch pressure-vacuum relief valves was assessed with respect to the stresses induced by the valve-to-operator interfacing hardware under operating loads during a LOCA. This analysis demonstrates that the 10-inch pressure-vacuum relief valves (VCS and VC6) will operate in the event of a LOCA. Technical Specifications allow 9.4-35 SGS-UFSAR Revision 16 January 31, 1998 the valves, normally maintained shut in Modes 1, 2, 3, and 4, to be intermittently opened under administrative control for safety purposes all modes of The accident (see item Sa, below) doses well within 10CFR50.67 ld. The isolation valves and control system provisions for isolation meet the appropriate safety-related criteria consistent with containment isolation. Containment Purge System isolation is actuated by Phase A and high radiation signals. le. Instrumentation and Control Systems are independent and actuated by diverse parameters. lf. lg. SGS-UFSAR The purge and pressure-vacuum relief isolation valves are to and close within 2 seconds. The valves were tested at the will be tested periodically in accordance with the Technical Specifications. Total isolation time, including the 2-second valve closure, will not exceed 5 seconds if initiated by a high containment pressure signal (based on a design basis double-ended cold leg rupture). Isolation time will not exceed 10 seconds if initiated by a high containment radiation Isolation is also initiated by a ection To ensure isolation valve type, location, orientation, the design, which includes the and configuration of valves and piping/ducting of the Penetration and Ventilation System, considers the potential problem of debris becoming entrained in the escaping air and steam. Where the containment purge and pressure-vacuum relief penetrations are not connected directly to a filtered ventilation system and are terminated in the free containment atmosphere, the are faced down to 9.4-36 debris from Revision 25 October 26, 2010 the system. All the valves are either contained within the piping/duct lines or have a l-inch expanded metal mesh basket around them. 2. The Containment is not intended for and temperature control within the containment, but was designed to perform the functions previously described. 3. The Containment Ventilation System utilizes fan coolers for temperature and humidity control. The Iodine Removal System (internal cleanup) is used to remove gaseous iodine and from the containment 4. The isolation valves are testable for and in accordance with the Technical 5a. The dose analysis for a LOCA during containment pressure relief is presented in Section 15. This analysis utilizes very conserva-cive assumptions, including an iodine spike. The results in doses well within 10CFR50.67 guideline values. 5b. The includes to structures and All necessary to automatic isolation of the containment purge and pressure-vacuum relief lines is external to the containment (except the inboard isolation valves) and would not be affected by a LOCA. 5c. The analysis of a double-ended pipe rupture (see Section 15) indicates less than 0. 2 percent of the Reactor Coolant System mass would be released from the containment to isolation. This w:'._ll not adversely affect Emergency Core 9.4-37 SGS-UFSAR Revision 25 October 26, 2010 Sd. The allowable leak rate is specified in the Technical Specifications. Based on the above, it is concluded that the design of the Containment Purge and Pressure-Vacuum Relief Systems satisfies the requirements of BTP CSB 6-4. 9.4.4.4 Teats and Inspegtions All components of the Containment Ventilation system are subjected to a test and inapection program. The performance of unitized equipment, auch aa fans, filters, cooling coila, isolation valves, dampers, etc., is verified through manufacturers
  • teats and inspection*. The performance of field-erected sections, such aa filter enclosures and duct work, is verified mainly through post-erection tests and inspectiona. After installation, all unitized equipment and field-erected sections are inspected, tested and adjusted to assure performance of their design function. During plant operation, periodic tests and inspections are performed to ensure the integrity and performance of all components. All components are inapected when delivered to the site to assure compliance with specifications. All components of the containment Fan cooler System are designed to withstand normal and LOCA conditions without loss of function. When it is impractical to subject components to full scale testing, conservative calculations and/or prototype teats are performed to demonatrate capability to resist LOCA and seismic effects. The Pressure-Vacuum Relief system for the Containment Building is expected to be used intermittently during normal operations. When operated, the system will maintain containment internal pressure between 0.3 psi positive and 1.5 psi negative. 9.4-38 SGS-UFSAR Revision 16 January 31, 1998 -

Station personnel can read local manometers at the equipment during system startup to see if filter pressure drops are approaching their design limits. Also, a sample of the charcoal filter will be available in the pressure relief unit for removal and testing to determine the efficiency of the charcoal filter. 9.4.5 Diesel Generator Area Ventilation 9.4.5.1 Design Bases The Ventilation Systems are designed to limit the temperature of each diesel generator compartment to 120°F and each Control Room to 110°F in the summer with equipment in the room operating. The unit heaters are designed to limit the temperature in the rooms to 60°F minimum in the winter. This range of room temperature (60°F to 110°F or 120°F) is an adequate environment for reliable operation and maintenance of the diesel generator, its controls and instrumentation. The ventilation capacity for each diesel generator compartment (40,000 cfm) and Control Room (1,200 cfm) is based on the waste heat released to the space. The ventilation capacity for the fuel oil storage area (2, 800 cfm) provides 5 air changes per hour. The ventilation equipment and controls for the diesel generator compartments and Control Rooms can be powered from the Standby AC Power System and is designed to seismic Class I criteria. The fuel oil storage area ventilation is powered by the Normal AC Power System and is designed to seismic Class II criteria. The seismic design and analysis methodologies used to qualify all ductwork and the contained equipment are described in Section 3.8.4.4.1. 9.4.5.2 System Description 9.4.5.2.1 General Description The Diesel Generator Area Ventilation System is shown on Plant Drawings 205321 and 205322. The diesel generator area for each plant consists of three diesel generator compartments, three diesel generator Control Rooms and a fuel oil storage area. Each of these spaces is provided with an independent, once-through ventilation system. The use of independent systems enhances the effectiveness of the Carbon Dioxide Flooding System in the event of a fire, permitting selective flooding into a given space without affecting other spaces. In the event carbon dioxide is delivered to a space, the ventilation for that space is automatically terminated. 9.4-39 SGS-UFSAR Revision 27 November 25, 2013 The diesel generator compartment Ventilation Systems are designed to start automatically and limit the maximum room temperature when the diesel generators are operating. Provisions are available to permit starting or testing individual systems during normal plant conditions when the diesel generators are not running. The Control Room Ventilation Systems are normally placed in air automatic mode. In this mode, a local thermostat for each room provides on-off control of its supply fan to regulate temperature. A local ON-AU'l'O-OFF switch is provided to permit manual operation of the fan. The ventilation system for the fuel storage area is also normally placed in an automatic mode. In this mode a local thermostat provides on-off control on the exhaust fan to regulate the space temperature. A local ON-AUTO-OFF switch is provided to permit manual operation of the fan. The Diesel Generator Area and Diesel Generator COntrol Room ventilation systems both consist of l) a supply fan bringing outdoor air into the building and 2) supply air ductwork which directs the supply air into the environmental spaces. The Ventilation System for the fuel storage area consists of 1) an exhaust fan discharging to the outdoors and 2) a supply air duct which supplies outdoor air to the room. Local unit heaters assure an adequate minimum temperature in the spaces during cold weather. 9.4.5.2.2 System Operation The Diesel Generator Area, Diesel Generator Control Room and FUel Oil storage Area ventilation systems are all normally operated in an automatic mode. The Control Room and Fuel Oil Storage Area ventilation fans are controlled (on-off) by local thermostats to regulate the environmental apace temperatures. The Diesel Generator Area ventilation fans are energized only when the diesel generators are started. All of these Ventilation Systems can be started independently, however, for testing and maintenance. 9.4-39a SGS-UFSAR Revision 14 December 29, 1995 THIS PAGE INTENTIONALLY BLANK 9.4-39b SGS-UFSAR Revision 14 December 29, 1995 The Diesel Generator Area Ventilation system utilizes a single-speed supply fan to direct outdoor air to the Diesel Generator engine room through supply air ductwork. The air is exhausted through openings in the ceiling of the engine room into the silencer area and is then exhausted outdoors through roof mounted penthouses. Temperature regulation for this area is accomplished through thermostatically controlled modulating dampers which regulate the volume of incoming outdoor air and recirculated indoor air. The Diesel Generator Control Room ventilation system utilizes a single-speed supply fan to direct outdoor air to the control room through supply air ductwork. The air is exhausted to the outdoors through a roof mounted penthouse. Temperature regulation for the control room is accomplished through thermostatic, on-off control of the supply fan. The fuel oil storage area utilizes a single-speed exhaust fan which discharges to the outdoors. Supply air is drawn into the area from the outdoors through supply ductwork. Temperature regulation for this area is accomplished through thermostatic, on-off control of the exhaust fan. 9.4-40 SGS-UFSAR Revision 14 December 29, 1995 -

Each system will automatically shut down if carbon dioxide fire protection flooding is initiated for the space. If the ambient in a diesel or Control Room exceeds 110°F or goes below 40°F, the condition is alarmed in the Unit Control Room. 9.4.5.3 '::'he and of the diesel generat:or area is on outdoor temperature limits of 0°F in winter and 95°F in summer. For the Salem site, these values satisfy more than 99 percent of the conditions experienced annually. There is, therefore, a conservative margin in the heating and ventilating systems to assure that the design temperatures for the spaces can be maintained. Heaters are provided in the Lube Oil System and in the Jacket \-'Jater System to assure each diesel generator is maintained at: a temperature at which it can be started in 13 seconds. This condition is satisfied for an outside temperature of 0°F and an inside ambient temperature of 40°F. The Ventilation Systems for the physically separated and powered provided with its own controls. diesel generator areas from separate sources. are independent, Each system is In the event of a fire in one space, the Ventilation System for that space is and does not feed air to the fire. The other diesel generators are available with full ventilation. contacts, that the ventilation are by the operation of switches in the Control Room if a station seismic event is detected. 9.4-41 SGS-UFSAR Revision 25 October 26, 2010 9.4.5.4 Tests and Inspections All equipment and components of the diesel generator area Ventilation Systems are subject to a program of tests and inspections. 9.4.6 Switchgear and Penetration Area (SPAV) Ventilation System 9.4.6.1 Design Basis and Criteria The Switchgear and Penetration Area Ventilation (SPAV) System is designed to maintain safe levels of temperature and cleanliness in the rooms served. Standby equipment is included in the system to assure the maintenance of these design conditions. The system is seismic Class I. The seismic design and analysis methodologies used to qualify all ductwork and the contained equipment are described is Section 3. 8. 4. 4. 1. The Ventilation System is designed to maintain the areas served by this system between a temperature range of 65°F-110°F except for the following areas: El. 64' Security Battery Room El. 64' Elevator Machinery Room El. 84' Main Corridor El. 84' Unit 1 Switchgear Room 115°F (SEE NOTE) 115°F NOTE: Not applicable, no safety related equipment in this area. The design basis outdoor air temperature is 0°F (winter) and 95°F (summer). A 10°F daily temperature variation may be used for summer operations, in accordance with ASHRAE methodology. These temperature values satisfy more than 99 percent of the conditions experienced at the site area annually. 9.4.6.2 System Description 9.4.6.2.1 General Description An independent Ventilation System is provided for each unit's Switchgear Rooms which are located on Elevations 84 feet and 64 feet, Mechanical Penetration Area (El. 100'), and the Electrical Penetration Area (El. 78') of the Auxiliary Building. The SPAV System consists of a supply air roll filter and enclosure, three supply air fans, two Penetration Area exhaust fans, two return/ exhaust fans, recirculation duct, supply and exhaust ducts, and control dampers. Most of the equipment is located in the penetration areas at Elevation 100 feet of each unit. structures. All ventilated areas and equipment are enclosed in seismic Class I The Switchgear Ventilation System is shown on Plant Drawings 205248 and 205348. 9.4-42 SGS-UFSAR Revision 27 November 25, 2013 9.4.6.2.2 System Operation The Ventilation System for each unit consists of the following equipment: 1. one 100-percent capacity supply-air filtering unit having 70-82 percent ASHRAB weight arrestance efficiency to filter the outside and recirculated air. 2. Three 50-percent capacity fans to supply filtered air through supply ducts to the various areas. 3. Two 100-percent capacity return/exhaust air fans to either exhaust air out of the switchgear rooms or return air for recirculation. 4. s. 6. 7. TWo exhaust fans for the Mechanical Penetration Area (Elevation 100 I feet) and electrical penetration area (Elevation 78 feet). Three recirculation cooling units serve the north (mechanical) penetration area at Elevation 100 feet, each consisting of a filter, cooling coil and fan. Control and instrumentation. Distribution ductwork and dampers for the supply air, exhaust air or recirculation air. Normally two of the three supply fans operate with the third fan as a standby. one of the return/exhaust fans operate with the second fan in standby and both of the penetration area exhaust fans operate. Supply temperature will be monitored and outside air intake dampers, recirculation damper, and exhaust damper will modulate to provide relatively constant supply air temperature to all areas of this system. When the supply air temperature is equal to or above 75°F, the system will be aligned to supply 100' outside air; that is, the recirculation damper closed and the intake and exhaust dampers fully opened. When the supply air temperature is between 65° and 75°F, the intake dampers, the recirculation damper, and the exhaust damper modulate to temper the supply as required to maintain temperature. 9.4-43 SGS-UFSAR Revision 16 January 31, 1998 When the supply air temperature is equal to or less than 65°F, both penetration area exhaust fans stop. The two supply fans and the switchgear return/exhaust fan continue to operate at full flow. In this the recirculation damper is 100% open and the outside air intake are 100% closed. By the access door of the other Unit's SPAV air handling unit housing is opened to equalize pressure in the electrical penetration area and mechanical equipment rooms. Both switchgear rooms (El. 64' & 84') and electrical penetration area (El. 78') are provided with a fire detection system. If operation of the Fire Protection System for one of these areas is initiated, the supply and exhaust dampers for the affected area close. For the switchgear rooms, the main recirculating dampers close and the as a system supplying 100 percent fresh air. This prevents the tripping of other smoke detectors by recirculated smoky air. The ventilation system also provides a means for purging smoke from the fire area as soon as air supply is re-established. 9. 4. 6. 3 The ventilation equipment for the structure. The Equipment Room SPAV are enclosed in a seismic Class I accessible from the Relay Room of the control area. All other areas in the vicinity of the Switchgear Rooms are ventilated by systems which are completely independent of the SPAV System and thus fire and smoke generated in such other areas would not impair the integrity or accessibility of the Switchgear Rooms. 9.4-44 SGS-UFSAR Revision 24 May 11, 2009 9.4.6.4 The SPAV system is inspected, tested and balanced upon installation. operation serves as a continuous check on system operation. Normal Operation of the dampers, including those associated with initiation of the Carbon Dioxide Fire Protection System, can be checked periodically. 9.4.7 Service Water Intake Structure Ventilation 9.4.7.1 The Ventilation Systems are designed to limit the of each compartment and/or Control Room to ll0°F during ambient conditions of 95°F with all equipment operating. The unit heaters are sized to limit the temperature in the areas to a nominal 60°F in the winter during ambient condition of 0°F. Reliable operation of the service water pumps, their controls and instrumentation is assured for a temperature range of 40°F-ll0°F. The ventilation capacity for each service water intake structure compartment and Control Room is based on the calculated waste heat released. The exhaust fans (12, 000 and 32,000 cfm capacity) and their controls and instrumentation are designed to Class I (seismic) criteria and can be powered from the Standby AC Power System. The air intake penthouse, supply and exhaust dampers are of non-seismic construction. The seismic design and analysis methodologies used to qualify all ductwork and the contained equipment are described in Section 3.8.4.4.1. 9.4.7.2 System Description 9.4.7.2.1 General Description The service water intake structure for both units consists of four service water intake compartments, each with its own Control Room. Each of these compartments is provided with an independent, once-through Ventilation System. The service water intake structure Ventilation Systems are designed to start automatically and limit the maximum room temperature when the service water pumps are operating. 9. 4-45 SGS-UFSAR Revision 24 May 11, 2009 The Ventilation System for each compartment consists of an outsice air intake penthouse, power-operatea intake ana exhaust campers, and two exhaust fans discharging to the outaoors. Local unit heaters assure an adequate minimum temperature in the spaces during cold weather when no pumps are in operation. 9.4.7.2.2 system Operation The service water intake structure Ventilating systems operate automatically in response to compartment and/or Control Room temperatures. The Ventilation Systems operate as follows: on a small rise in temperature, the smaller of two exhaust fans starts and cischarges to the outdoors. The supply air from the outdoors is modulated by room thermostats to provide the design compartment or Control Room temperature. On a greater rise in temperature, the larger fan starts, its intake damper opens and more air is induced to flow through the compartments. When a system is shut down, its exhaust fans stop and the supply and exhaust air dampers return by spring action to their closed positions. Prior to the ambient temperature in compartments or Control Rooms exceeding llO"F or going below 40"F, the condition is alarmed in the Control Room. 9.4.7.3 Design Evaluation The heating and ventilating of the service water intake structure area is predicted on outdoor temperature limits of 0°F in winter and 95°F in summer. For the Salem site, these values satisfy more than 99 percent of the conditions experienced annually. This is, therefore, a conservative margin in the Heating and Ventilating Systems to assure that the design temperatures for the spaces can be maintained. 9.4-46 SGS-UFSAR Revision 17 October 16, 1998 -

The Ventilation Systems for the service water intake structure compartment use two fans which are physically and powered from separate sources. Each system is provided with its own controls, can be started manually or automatically, and can be tested independently to assure its availability. Failure of the non-seismic ventilating equipment (dampers and intake would not interfere with the ability of the exhaust fans to perform their design function. The dampers fail open or loss of air or electric power. 9. 4. 7. 4 The is inspected and tested upon installation. Normal serves as a continuous check on system operation. 9.4.8 References for Section 9.4 1. USNRC Regulatory Guide 1.183, Alternative Radiological Source Terms for Evaluating Design Basis Accidents at Nuclear Power Reactors, July 2000 2. 10 CFR Part 20, Appendix B, Annual Limits on Intake {ALis) and Derived Air Concentrations (DACs) of Radionuclides for Occupational Exposure; Effluent Concentrations; Concentrations for Release to Sewerage 3. 10 CFR Part 50 Appendix I, Numerical Guides for Design Objectives and Limiting Conditions for Operation to Meet the Criteria "As Low as is Reasonably Achievable" for Radioactive Material in Nuclear Power Reactor Effluents 4. 40 CFR Part 190, Protection of Environment, Environmental Radiation Protection Standards For Nuclear Power Operations 5. Salem Units 1 and 2 Offsite Dose Calculation Manual (ODCM) 9.4-47 SGS-UFSAR Revision 23 October 17, 2007

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