LR-N17-0034, Salem Generating Station, Units 1 & 2, Revision 29 to Updated Final Safety Analysis Report, Section 11.4, Radiological Monitoring
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11.4 RADIOLOGICAL MONITORING 11.4.1 Design Objectives Design objectives for the Radiation Monitoring System (RMS) are as follows: 1. Warn of any radiation hazard which might develop 2. Give early warning of a plant malfunction which might lead to a radiation hazard or plant damage 3. Provide assurance that personnel exposure does not exceed 10CFR20 limits 4. Provide assurance that atmospheric releases will not exceed the design objectives of 10CFR50 5. Record the activity present at various plant locations 6. Provide data for radiological analyses and reports 7. Monitor process system filters for radiation buildups 11.4.2 Radiation Monitoring System The RMS provides instrument channels, located at selected points in and around the plant to detect, compute, and record the radiation levels. In the event the radiation level should rise above a desired setpoint, an alarm will be initiated in the Control Room. The RMS operates in conjunction with regular and special radiation surveys and with chemical analyses performed by the plant staff to meet the radiological monitoring design objectives presented in Section 11.4.1. The RMS signal processing equipment is centralized in six cabinets for Unit 1 and in three cabinets for Unit 2. High reliability and 11.4-1 SGS-UFSAR Revision 27 November 25, 2013 ease of maintenance are emphasized in the design of this system. Cabinet equipment is equipped with sliding channel drawers for rapid replacement of units, assemblies and entire channels. It is possible to completely remove the various chasses from the cabinet, after disconnecting the cables from the rear of these units. The components of the RMS are designed to meet or exceed the requirements of normal and DBA conditions for temperature, humidity, pressure and radiation, as stated in the Salem Generating Station Environmental Design Criteria. The RMS is divided into the following subsystems: 1. The Process Radiation Monitoring System monitors various gaseous and liquid streams for indication of increasing radiation levels, and all identified effluent paths to establish the quantity of radioactivity being discharged to the environment. 2. SGS-UFSAR The Process Filter Monitoring System monitors the buildup of radioactivity on various process filters to warn of unexpected radiation and to indicate the need for changing or cleaning the filter. 11.4-2 Revision 19 November 19, 2001
- 3. The Area Radiation Monitoring System monitors radiation levels in various locations of the plant to warn personnel of a deteriorating radiological condition. It is also useful in assessing the spread of radioactivity in a given area. 11.4.2.1 Radiation Monitoring System Description 11.4.2.1.1 Radiation Monitoring System-Unit 1 Except for 1R18, 1R2, 1R3, 1R4, 1R5, 1R6A, 1R 7, 1R9, 1R1 OA, 1R11A, 1R12A, 1R128, 1R13A, 1R138, 1R15, 1R17A, 1R178, 1R18, 1R19A, 1R198, 1R19C, 1R19D, 1R41A, 1R418, 1R41C, 1R41D, 1R4 6A, 1R4 68, 1R4 6C, 1R4 6D, 1R53A, 1R538, 1R53C, and 1R53D, the Unit 1 RMS consists of analog channels which monitor radiation levels in various plant locations and operating systems. Monitors 1R18, 1R41A, 1R418, 1R41C, 1R4 6A, 1R4 68, 1R4 6C, 1R4 6D, 1R53A, 1R538, 1R53C and 1R53D have microprocessor-based electronics. A digital control and display module is located in the Control Equipment Room for monitors 1R18, 1R41A, 1R418 and 1R41C, 1R4 6A, 1R4 68, 1R4 6C, 1R4 6D, and in the Relay Room for monitors 1R53A, 1R538, 1R53C and 1R53D. The output from each detector is transmitted via cables to the RMS cabinets in the Control Room area where the radiation level is indicated on a meter and pre-selected channels are recorded on a multipoint recorder. For area monitors, the radiation level is also indicated locally at the detector. High radiation level alarms are annunciated on the Control Room overhead annunciator and further identified at the RMS cabinets. For area monitors, a high radiation level is also alarmed at the detector location, except for area monitors located in the Control Room. Each channel contains a completely integrated modular assembly, which includes the following. 1. Level Amplifier/Discriminator Discriminates and amplifies the detector output to provide a discriminated and shaped pulse output to
- the log level amplifier. 2. Log Level Amplifier -Accepts the shaped pulse of the level amplifier output,* performs a log integration (converts total pulse rate to a logarithmic analog signal) , and amplifies the resulting output for suitable indication and recording.
- Note, monitors 1R18, 1R41A/8/C/D and 1R53A/8/C/D have microprocessor based electronics that provide a direct digital conversion of detector output to CPM. 1R18 contains two channel inputs and monitors both Control Room area inlet ducts as illustrated on Figure 11.4-9. 11.4-3 SGS-UFSAR Revision 25 October 26, 2010
- 3. Power Supplies -Individual power supplies are contained in each drawer for furnishing the positive and negative voltages for the transistor circuits, relays and alarm lights and for providing the high voltage for the detector. 4. Test-Calibration Circuitry-These circuits provide a pre-calibrated pulsed and/or analog signal to perform a channel test, and a solenoid operated radiation check source to verify the channel's operation. A light on the Control Room overhead annunciator indicates when any channel is in the test-calibrate mode, except 1R1B. 5. Radiation Level Meter -This meter, mounted on the assembly drawer, has ' ' ' 101 106 a scale callbrated logarl thmlcally from to for process monitor channels and in mR/hr for area channels. For monitors 1R1B, 1R41A/B/C/D, and counts per minute and filter monitor 1R53A/B/C/D, the displays are digital. Pre-selected signals are also recorded and displayed in the Control Room area. 6. Indicating Lights -These lights indicate high radiation levels and circuit failures. A light on the Control Room overhead annunciator is actuated on a high radiation signal and a yellow light on the RMS recorder panel indicates which channel. provides discriminate 1R1B channel alarms. applicable for 1R1B. The Control Room alarm CRT The yellow light is not 7. Bistable Circuits-Two bistable circuits are provided, one to alarm on high radiation (actuation point may be set at any level over the range of the instruments) and one to alarm on loss of signal (circuit failure). 8. Check Source -A remotely-operated long half-life radiation check source is furnished in each channel. The energy emissions are similar to the radiation energies being monitored. The source strength is sufficient to cause a visible increase in the meter indication. During checksource operation on R1B indication is frozen for both channels. If insufficient count rate is achieved (check source count rate compared against a setpoint), a norm failure alarm is provided. 11.4-4 SGS-UFSAR Revision 19 November 19, 2001 RMS channels 1R1 7A, 1R1 78, 1R2, 1R3, 1R4, 1R18, 1R19A, 1R5, 1R19B, 1R6A, 1R7, 1R9, 1R10A, 1R13A, 1R13B, 1R15, 1R19C, 1R19D, and 1R4 0 are microprocessor based digital instrumentation systems. This equipment is designed to power, operate, and monitor various types of radiation detectors. The system consists of a detector (GM tube, scintillation, or ion chamber), a local monitor, and a remote monitor. Local monitors perform pulse discrimination and shaping. Also, all calibration constants are stored in the local monitor. Remote monitors communicate with the local monitors via serial communication ports and provide analog outputs to the plant computer and indicators and contact outputs to alarm and interlocks. RMS channels 1R11A, 1R12A, and 1R12B are microprocessor based digital instrumentation systems. A sample skid with a local microprocessor monitors containment atmosphere for particulate iodine and noble gas. Detector signals are processed locally. Alarm contacts are located at the microprocessor. Calibration and database constants are stored locally. A remote display unit communicates with the local microprocessor via a serial communication port. The remote display provides analog outputs to plant computers, indicators and contact outputs for annunciation. 11.4.2.1.2 Radiation Monitoring System-Unit 2 The Unit 2 RMS is primarily a microprocessor-based digital monitoring system. The system is basically a two-tiered structure with local field units and remote units in the Control Equipment Room. A simplified diagram of the general system structure is shown on Figure 11. 4-1. 2R1B has microprocessor-based electronics and a digital control and display assembly in the Control Equipment room as illustrated on Figure 11.4-9. Local Field Units The local digital field units are located at selected points in the plant to detect airborne radioactivity, filter buildup radioactivity and process system radioactivity. Each field unit consists of a detector and a microprocessor I electronics cabinet. The units detect, compute, and indicate radiation data at their respective location. A digital display is provided for radiation level indication. Indicating lights are provided for alarm, warning, failure, and check source operation information. Auxiliary relay contacts are available for control system functions to indicate alarm, warning, and failure conditions. Keylock controls are used for testing, calibration, and entering data such as setpoints, conversion factors, and confidence levels. 11.4-5 SGS-UFSAR Revision 27 November 25, 2013 This page intentionally left blank 11.4-6 SGS-UFSAR Revision 27 November 25, 2013 The system was designed to provide for the safe operation of the plant, to assure that personnel exposure does not exceed 10CFR20 limits, and to assure that environmental releases do not exceed Technical Specification limits. The Unit 2 system was designed to meet the same requirements as the Unit 1 system. The two Radiation Monitoring Systems perform essentially the same functions. There are, however, some differences in sensitivities, detector types, and monitoring channels. 11.4.2.2 Process Radiation Monitoring System Channel Description The process monitors are utilized for monitoring process systems for potential radiation leakage and effluent discharge paths for normal releases and those following potential accidents. liquid or gas sampling system. The monitors typically incorporate an offline Some of the units monitor the process stream directly. Typical functional block diagrams of the process monitors are shown on Figures 11.4-2 through 11.4-7. The Process Radiation Monitoring System is summarized in Tables 11. 4-1 and 11.4-2 and consists of the following radiation 11.4-7 SGS-UFSAR Revision 27 November 25, 2013 monitoring channels. The prefix numbers indicate monitors associated with Unit 1 or Unit 2. Control Room Area Intake Duct Monitors (1-R1B and 2-R1B) The Control Room Intake Air Radiation Monitoring System is a shared system. The R1B monitors provide redundant functions to monitor air drawn into the Control Room through the Unit 1 and Unit 2 air intakes to the Control Room. The dual channel processors with beta scintillation detectors in each of the Unit 1 and Unit 2 Control Room intake ducts provide the redundant initiation signals to place the ventilation system into its accident-pressurized mode of operation. In addition, the monitoring system provides continuous indication and recording of the radiation levels and annunciates in the Control Room the failures of the radiation monitoring equipment and the development of warning and alarm level radiation conditions. This is a safety-related channel. Containment -Air Particulate Monitors (1-R11A and 2-R11A) These monitors are provided to measure air particulate beta radioactivity in the containment and to ensure that the release rate through the plant vent during purging is maintained below specified limits. For Unit 1, channel R-11A takes a continuous air sample from the containment atmosphere. For Unit 2, channel 2-R11A takes a sample from the containment. The sample is drawn from the containment through a closed, sealed system and monitored by a scintillation counter-moving filter paper detector assembly. The filter paper collects 99 percent of all particulate matter greater than 1 micron in size on its constantly moving surface and is viewed by a photomultiplier-scintillation crystal combination. 11.4-8 SGS-UFSAR Revision 25 October 26, 2010 The sample is returned to the containment or vent, depending on which source is being monitored. The detector assembly is in a completely enclosed housing. The detector is a hermetically sealed photomultiplier tube scintillator combination. The filter paper has a 25-day minimum supply at normal speed. Lead shielding is provided to reduce the background level to where it does not interfere with the detector's sensi ti vi ty. The filter paper mechanism, an electro-mechanical assembly which controls the filter paper movement, is provided as an integral part of the detector unit. Channel 1R11A (particulate) monitors containment for leak detection and effluent releases. Digital indication for 1R11A is located at the local and remote monitors. The monitors are set to indicate radiation from 101 to 106 cpm. The local monitor provides Normal, Warn and Alarm indications. The remote monitor in the Control Equipment Room, in addition to display and status indications on the monitor panel, provides analog outputs to the Safety Parameter Display System (SPDS), Plant Computer P250, indicators on Panel 1RP1, indication of high radiation on Panel 1RP1, and High/Trouble alarm on the Overhead Annunciator. Containment/Plant Vent Radioactive Gas Monitors (1-R12A, 2-R12A, 1-R41C and 2-R41D) These monitors are provided to measure gaseous radioactivity in the containment, and to ensure that the release rate through the plant vent during purging is maintained below specified limits. High radiation level initiates closure of the containment purge supply and exhaust duct valves and pressure relief line valves. discharge valve. For Unit 2, high radiation level also closes the waste gas For Unit 1, channel 1-R12A takes a continuous air sample from the containment atmosphere. Channel 1-41D samples only the plant vent. For Unit 2, channel 2-R12A takes a sample from the containment and channel 2-R41D from the plant vent. All samples reach the gaseous detector after passing through the air particulate monitor or an air particulate sampler (1-R41D only). The sample is constantly mixed in the fixed, shielded volume, where it is viewed by beta scintillator. The sample is then returned to the source being monitored. The detector assembly is in a completely enclosed housing containing a beta-gamma sensitive detector mounted in a constant gas volume container. Lead shielding is provided to reduce the background level to a point where it does not interfere with the detector's sensitivity. 11.4-9 SGS-UFSAR Revision 25 October 26, 2010 Channel 1R12A (noble gas) monitors containment for effluent releases. Digital indication for 1R12A is located at the local and remote monitors. The monitors are set to indicate radiation from 101 to 106 cpm. The local monitor provides Normal, Warn and Alarm indications and provides an alarm relay contact for initiating closure of containment ventilation closure/isolation valves 1VC1, 4, 5, and 6 for Modes 1, 2, 3, 4 & 5. The remote monitor in the Control Equipment Room, in addition to display and status indications on the monitor panel, provides analog outputs to the Safety Parameter Display System ( SPDS) , Plant Computer P250, indicators on Panel 1RP1, indication of high radiation on Panel 1RP1, and High/Trouble alarm on the Overhead Annunciator. Containment -Fixed Filter Iodine Monitor (1-R12B, 2-R12B) Iodine is one of the more prominent isotopes requiring special surveillance. The containment monitoring system has been designed so that the sample flows first through the filter paper assembly and then through a charcoal cartridge. It is a scintillation type detector. For Unit 1, the sample is drawn from the containment for channel 1-R12B. Channel 1-R41C samples only the plant vent. For Unit 2, channel 2-R12B takes a sample from the containment. High radiation level initiates closure of the containment purge supply and exhaust duct valves and pressure line relief valves. The abnormal conditions are alarmed in the Control Room and Control Equipment Room. A solenoid-operated check source is provided to give an instant checkout of the system functional status. Channel 1R12B (iodine) monitors containment for effluent releases. Digital indication for 1R12B is located at the local and remote monitors. The monitors are set to indicate radiation from 101 to 106 cpm. The local monitor provides Normal, Warn and Alarm indications and provides an alarm relay contact for initiating closure of containment ventilation closure/isolation valves 1VC1, 4, 5, and 6. The remote monitor in the Control Equipment Room, in addition to display and status indications on the monitor panel, provides analog outputs to the Safety Parameter Display System (SPDS), Plant Computer P250, indicators on Panel 1RP1, indication of high radiation on Panel 1RP1, and High/Trouble alarm on the Overhead Annunciator. Note The containment radiation monitors (channels R11, R12A, and R12B) have elements common to all three channels of the particulate/noble gas/ iodine monitoring assembly. These are described as follows: 11.4-10 SGS-UFSAR Revision 24 May 11, 2009
- 1. The flow control assembly includes a pump unit and selector valves that provide a representative sample (or a "clean" sample) to the detectors. 2. The pump unit consists of: a. A pump to obtain the air sample b. A flowmeter to indicate the flow rate c. A flow control valve to provide flow adjustment d. A flow alarm assembly to provide low and high flow alarm signals 3. Selector valves are used to direct the desired sample to the detector for monitoring and to block flow from the sampling area when the channel is in the maintenance or "purging" condition. 4. A temperature sensor is used to protect the system from high temperature. This unit automatically closes the inlet motor operated valve upon a high temperature condition. 5. Purging is accomplished with a valve control arrangement whereby the normal sample flow is blocked and the detector purged with a "clean" sample. This facilitates detector calibration by establishing the background level and aids in verifying sample activity level. 6. For Unit 1, the flow control panel in the Control Room radiation monitoring racks permits remote operation of the flow control assembly. By operating a sample selector switch on the control panel, either the containment or a local "clean" sample may be monitored. these controls are located on 2RP1 in the control room. For Unit 2, 7. Deleted. 8. Containment isolation valves are provided for the containment sample piping. In addition, the containment isolation valves (for regular and backup flow paths) limit switch auxiliary relays are wired to the Auxiliary Annunciator System to provide a 1R11/12 loss of flow path alarm whenever both backup and regular flow paths are lost. 9. For Unit 2, the containment particulate and gaseous monitors (2-R11A and 2-R12A) are also used as part of the Reactor Coolant Leak Detection System. 11.4-11 SGS-UFSAR Revision 25 October 26, 2010 Alarm lights are actuated by the following: 1. Flow alarm assembly (low or high flow) 2. The pressure sensor assembly (high pressure) 3. The filter paper sensor (paper drive malfunction) 4. The pump power control switch (pump motor on) Containment Fan Cooler Radiation Monitors (1-R13A and B and 2-R13A and B) Service water is used as the cooling medium for the containment fan coolers and could be contaminated if the cooling coil leaks. Since the Service Water System discharges to the river, the fan cooler units will be monitored for radioactivity. This is done through the use of two monitors for the five fan coolers. Each monitor employs an in-line detector. in the Control Room are also provided. Condenser Air Removal Gas Monitors (1-R15 and 2-R15) Remote alarms and readout This channel monitors the discharge from the condenser air removal exhaust header for gaseous radiation which is indicative of a primary to secondary system leak. The gas discharge is routed to the plant vent. In Unit 1 a gamma sensitive scintillation detector is used to monitor the radiation level. The detector is inserted in an inline fixed volume container which includes adequate shielding to reduce the background radiation to where it does not interfere with the detector's sensi ti vi ty. coupled to a photomultiplier tube is used. 11.4-12 SGS-UFSAR In Unit 2, a gamma scintillator Revision 27 November 25, 2013 Component Cooling Liquid Monitors (1-R17A, Band 2-R17A,B) These channels continuously monitor the component cooling water for radiation. Leakage from the Reactor Coolant System and other systems' components to the component cooling water is detected by a scintillation counter located in an inline well. A high radiation level alarm signal initiates closure of the gas valve located in the component cooling surge tank vent line to prevent gaseous radiation release. Waste Disposal System Liquid Effluent Monitors (1-R18 and 2-R18) This channel continuously rnoni tors all Waste Disposal System liquid releases from the plant. Automatic valve closure action is initiated by monitor after a high radiation level is indicated and alarmed in the Control Room. A scintillation counter in a fixed volume assembly monitors liquid effluent as it is discharged. Remote indication and annunciation are provided on the Waste Disposal System control board. Stearn Generator Blowdown Liquid Monitors (1-R19A, B, C, D, and 2-R19A, B, C, D) Each of these channels (four channels per unit) monitors the liquid phase of the steam generators for radioactivity, which would indicate a primary-to-secondary system leak. The four steam generator blowdown sample lines each have a radiation monitor. In SGS-UFSAR 11.4-13 Revision 21 December 6, 2004 Unit 1, the monitors are located in the Sampling Room where the blowdown sample has been cooled. In Unit 2, an offline sampling system is used. A high radiation alarm signal will close the No. 12 ( 22) steam generator blowdown tank inlet valves and the steam generator blowdown isolation valves on the affected steam generator. Letdown Line Monitors (1-R31A and 2-R31) The Letdown Monitoring System for each unit consists of a single channel for monitoring total gross activity of the letdown line concentration. These monitors are also called failed fuel monitors. This purpose is to detect the failure of the cladding of one or more fuel elements by the gamma emission of fission products released into the reactor coolant. 1. Unit 1 System The system continuously measures gamma radiation intensity in a continuously flowing sample stream of reactor coolant water using a gamma scintillation detector. Besides continuous indication of the reactor coolant activity, high radiation conditions are alarmed in the Control Room. 6 The detector is capable of measuring up to 10 cpm at which position it will reach the saturation condition. Provision is made for desensitizing the system by two or more decades to compensate for permanent activity buildup resulting from long-term normal operation. This 11.4-14 SGS-UFSAR Revision 15 June 12, 1996 is accomplished by insertion of a lead spacer between the sensitive end of the detector and the letdown line. 2. Unit 2 System A gamma scintillator is used to monitor the total gross gamma letdown line activity concentration. Signal processing is performed by the digital RMS to provide data on a significant increase of gross gamma activity. A significant increase of gross gamma activity would be indicative of a fuel cladding failure. The detector is capable of measuring up to 1 X 109 cprn. Provision is made for desensitizing the system by two or more decades to compensate for permanent activity buildup resulting from long-term normal operation. This is accomplished by insertion of a lead spacer between the sensitive end of the detector and the letdown line. Evaporator and Feed Preheaters Condensate (1-R36) Heating steam is supplied to the boric acid and waste evaporators and feed heater. Condensate from the evaporators and feed heater is returned to the condensate receivers from whence it is pumped back to the heating boiler. Stearn is used in the tubes of the evaporators and in the heater for process heating. Since the evaporators and heater can contain radioactive fluids, a tube rupture could result in a contamination of the Condensate System, Heating Boiler System, and Heating Stearn System. 11.4-15 SGS-UFSAR Revision 27 November 25, 2013 This channel continuously monitors the activity in the common condensate piping from each unit's evaporators. This channel employs an offline sampler. A high radiation level alarm will automatically close the condensate line valve for each unit's evaporator packages. Alarm and indication are provided in the Control Room. A manually valved drain is provided for disposal of any contaminated condensate to the Waste Disposal System. Nonradwaste Basin Discharge (2-R37) The nonradwaste basin provides a potential release path due to the fact that steam generator blowdown is offline sampler is provided nonradwaste basin. directed to the basin during plant startup. An to continuously monitor the discharge from the Plant Vent High Range Monitors (1-R41B-D and 2-R41B-D, 1-R45 and 2-R45) The Plant Vent High Range Monitors consist of High Range Noble Gas Monitors (1-R41B-D and 2-R41B-D) and High Range Particulate and Iodine Sampling Skids (1-R45 and 2-R45). The High Range Noble Gas Monitors comply with NUREG-0737, Item II.F.1, and the intent of Regulatory Guide 1. 97, type C & E Category 2 requirements. The system provides a sampling capability of 105 !-LCi/cc for noble gases. The monitors are safety grade and qualified for the post-accident environment. However, the monitors do not perform any safety related function. The system is comprised of four noble gas channels as follows: low range noble gas (R41A), intermediate range noble gas (R41B), high range noble gas (R41C) and composite noble gas (R41D) . Microprocessor software logic is used for the composite channel to display the effluent release rate based on low-, intermediate-or high-range noble gas concentrations (R41A, B or C, respectively) and the plant vent flow rate. The High Range Particulate and Iodine Sampling Skids (1-R45 and 2-R45) comply with NUREG-0737, Item II.F.1, and the intent of Regulatory Guide 1.97, type E Category 3 requirements. The ' ' ' ' 2 system provldes a sampllng capablll ty of 10 !-LCi/cc for iodines and particulates. Nonsafety-related samplings conditions. SGS-UFSAR lines heat tracing during plant is provided to preclude outages coincident with 11.4-16 freeze-up adverse of the weather Revision 28 May 22, 2015 Main Stearn High Range Monitors (1-R46A-D and 2-R46A-D) The Main Stearn High Range Monitoring System complies with NUREG-0737, Item II. F .1, and the intent of Regulatory Guide 1. 97. The system provides a detection capability of 103 pci/cc. The monitors are safety grade and qualified for the post-accident environment. of the main steam lines. Channels R46A-D each monitor one Main Stearn Line N16 Radiation Monitors (1R53A/B/C/D and 2R53A/B/C/D) The Main Stearn Line N16 Radiation Monitoring System is one of the means used to detect and trend primary-to-secondary leakage in the main steam generators. It consists of four channels; each channel continuously rnoni tors the N16 gamma radiation from one of the main steam lines. The detectors are high temperature Nai (T1) gamma scintillators with an integral Arn241 check source. They are located upstream of the mixing bottle and as close to the main steam lines as practical. Detector output is processed by a rnul ti -channel-analyzer, and the count rates in two energy windows are rnoni tored for each channel. The high energy window is sensitive only to N16. Because N16 is present only during power operation, this monitor is used only during Mode 1. The monitor is not included in the Reg. Guide 1.97 monitoring systems, has no interlocks with other monitors or systems, and is non-safety grade. 11.4.2.3 Process Filter Monitoring System Channel Description Area-type radiation monitors are provided on these liquid (process) filters to determine when they should be replaced by indicating the level of activity given off by the filter. A high radiation level alarm is initiated in the Control Room. A radiation indicator and alarm light are located at the filter. The filters which are monitored include the following: 1. Reactor coolant filters (1-R26 and 2-R26) 2. Condensate filters (1-R40 and 2-R40) 11.4-17 SGS-UFSAR Revision 28 May 22, 2015
-1 4 All Unit 1 process filter monitors are GM tubes and have a range of 10 -10 mR/hr. All Unit 2 process filter monitors are ion chambers or Geiger Mueller detectors and have a range of 10-1 -10 6 mR/hr. They perform no control function. The following liquid (process) filters are monitored for differential pressure and radioactivity to determine when the filters should be replaced: 1. Seal water injection filters 2. Seal water filters 3. Liquid waste filters 4. Spent fuel pool filters 5. Spent fuel pool skimmer filters 6. Refueling water purification filters 7. Ion exchange filters 11.4.2.4 Area Monitoring System Channel Description Each channel consists of either a gamma sensitive GM tube detector or an ion chamber detector. Functional block diagrams of the area monitors are shown on Figures 11.4-7 and 11.4-8. For the Unit 1 analog channels, a meter is mounted on the front of each indicating-control module and is calibrated logarithmically from 0.1 mR/hr to 10 R/hr. In addition, one of the containment area monitors in Unit 1 is calibrated from 10 mR/hr to 1000 R/hr. A remote meter, calibrated logarithmically from 0.1 mR/hr to 10 R/hr (or from 10 mR/hr to 1000 R/hr) is mounted at the detector assembly. Radiation Monitoring System cabinet alarms consist of indicator lights for high radiation and detector or circuit failure. The remote meter and alarm assembly at the detector contains a red indicator light and an audible alarm which are actuated on high radiation. Both units have containment monitors capable of indicating area radiation from 1R/hr to 107R/hr. Unit 1 digital channels 1R2, 1R3, 1R4, 1R5, 1R6A, 1R7, 1R9, 1R10A, and 1R40 provide digital indication at the local and remote monitors. The monitors are set to indicate radiation from 0.1 mR/h to 10 R/h. The local monitors provide Normal, Fail, and Alert indications and initiates buzzer and beacon light on high alarm. The remote monitors in the Control Equipment Room, in addition to display and status indication on the monitor panel, provide analog outputs to the plant computer ( P250) and indicators on Panel 1RP1, indication of high radiation on Panel 1RP1, High/Trouble alarm on the Overhead Annunciator, and interlock contacts when required. Tables 11.4-3 and 11.4-4 give a summary of System. A listing of the area monitors is additional or special information added. 11.4-18 SGS-UFSAR the Area Radiation Monitoring also included below with any Revision 26 May 21, 2012
- 1. Control Room Area (Channel 2-R1A, 1-R1A) -This channel continuously monitors the Control Room area. This area monitor does not have its own integral flashing beacon and horn since it is located in the Control Room and an alarmed condition is indicated by the annunciator and audible alarm (Unit 2 is provided with LED alarm indication and an adjustable volume horn) vital power supply. This is a non-safety-related unit with a 2. Containment Area (Low Range) (1-R2, 2-R2) 3. Radiochemistry Laboratory (R3) 4. Charging Pump Room (1-R4, 2-R4) 5. Fuel Handling Building (Channels 1-R5 and 2-R5) -These channels continuously monitor the fuel storage areas. A high radiation alarm from either unit will initiate charcoal filtration of the Fuel Handling Building atmosphere. The Fuel Handling Accident in the Fuel Handling Building was analyzed without credit for filtration by the Fuel Handling Building Ventilation System. For Unit 2 the high radiation alarm will automatically start the exhaust fans. In addition to the integral alarm horn and flashing beacon, these units actuate an emergency evacuation horn in the building and radiation alert lights outside of the building. vital power supply. Each unit is on a separate 6. Sampling Room (R6A) 7. In-core Seal Table (1-R7, 2-R7) 8. Fuel Storage Area (1-R9, 2-R9) -These channels continuously monitor SGS-UFSAR the fuel storage areas. A high radiation alarm from either unit will automatically start the exhaust fans (Unit 2 only) and initiate charcoal 11.4-19 Revision 22 May 5, 2006 filtration of the Fuel Handling Building atmosphere. The Fuel Handling Accident in the Fuel Handling Building was analyzed without credit for charcoal filtration by the Fuel Handling Building Ventilation System. In addition to the integral alarm horn and flashing beacon, these units actuate an emergency evacuation horn in the building and radiation alert lights outside of the building. Each unit is on a separate vital power supply. 9. Containment Personnel and Equipment Hatches (1-R10A, B and 2-R10A, B) 10. Counting Room (R20B) 11. Containment Area (High Range) (1-R44 A and B and 2-R44 A and B) -These channels continuously monitor the containment area and are provided with a special ion chamber detector for extended range capability in a post-accident environment. power supply. This is a safety-related unit with a vital 12. Public Service Control Point (R23) 13. Fuel Handling and Cask Handling Cranes (1-R32 A and B, 2-R32 A and B) -These channels are not connected to the central Radiation Monitoring System and are not provided with integral horns and flashing beacons. A flashing beacon and alarm bell on the cranes are initiated. 14. Mechanical Penetration Area (2-R34) 15. Condensate Filter Area (1-R40 and 2-R40) 16. (Deleted) 17. Electrical Penetration Area (1-R47 and 2-R47) 11.4-20 SGS-UFSAR Revision 22 May 5, 2006
- 18. Technical Support Center (R51) 11.4.3 Sampling Samples are taken as required by the plant Technical Specifications. The plant vent will be continuously monitored for gross radioactivity. Additionally, a fixed paper particulate filter followed by a charcoal cartridge (Cesco or equivalent) is installed, both of which will be changed weekly. The charcoal cartridge and particulate filter will be analyzed by gamma spectroscopy within 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> from change out. A sample will be taken manually at a frequency not to exceed monthly, and an isotopic analysis performed to determine the identity and quantity of noble gases. The sample will be taken at a time when there are no gas decay tank releases or containment purges in progress, since these releases are not representative of a continuous release. Therefore, gas decay tank releases and containment purges will be analyzed isotopically on a batch basis. The method employed will be a grab sample, utilizing a gas collection device, taken from either of two sampling points in the plant vent. These samplers are the same as those used in conjunction with the continuous plant vent gas monitors outlined in Section 11.4.2.2. In order to ensure that the inline filter and cartridge sample is representative of the plant vent exhaust gas, a weekly isotopic analysis of the particulate filter and cartridge is performed. This isotopic inventory is used to determine the isotopic composition of the plant effluent. In the event that this equilibrium is upset by a refueling, process change, or a deviation of greater than 20 percent in the isotopic ratio established from the previous isotopic analysis (this does not apply while releasing gas decay tanks or during containment purging), a new isotopic analysis will be performed. 11.4-21 SGS-UFSAR Revision 18 April 26, 2000 In order to ensure sampling during a radiological emergency that might render the normal plant vent sampling station uninhabitable, a supplemental Plant Vent Sampling System is provided. The supplemental Plant Vent Sampling System is located in a region of the plant that is expected to be habitable during all accident conditions (west side of the Fuel Handling Building) . The supplemental system is designed such that it can be used during normal or accident conditions. The sample lines are heat traced to help ensure that a representative sample is being delivered to the supplemental sampling station. The controlled facilities ventilation duct is equipped with offline particulate and iodine samples that operate in parallel with its system operation. The cartridges are removed and analyzed whenever necessary. Samples are taken on each batch of liquid waste released. Station records contain the quantity and concentration of radioactive isotopes, the volume of each batch and estimates of the water flow for dilution. Each sample is analyzed for principal gamma emitters. Composites are prepared from each batch released during a month and analyzed for the principal gamma emitting nuclides, fission and activation products, gross alpha, and tritium. A quarterly composite analysis is also performed for Sr-89, Sr-90 and Fe-55. The sensitivities and frequencies of analyses comply with the requirements of Salem Technical Specifications. Information on sampling of the containment atmosphere and the Reactor Coolant System is included in Section 9.3. 11.4-22 SGS-UFSAR Revision 18 April 26, 2000 11.4.4 Inservice Tests and Calibrations Radiation monitors of the Radiation Monitoring System are initially calibrated to standards traceable to the National Bureau of Standards, most often referred to as "primary calibration". The area monitors undergo a range calibration by exposing the detectors to at least three radiation intensities from a Co-60 or Cs-137 source. The exception is the Containment High Range Area Monitors, which are calibrated with at least one intensity. The liquid and gas process monitors undergo "wet" isotopic calibrations with isotopes of an average energy comparable to those of the isotopes expected to be monitored. At least three concentrations of isotopes are used in calibrating the instruments. Beyond the initial primary calibration all radiation detectors undergo point source calibrations in a fixture with repeatable geometry, most often referred to as a "secondary calibration" or "transfer calibration". This fixture and the button sources are utilized for periodic field calibrations. It is typical practice to use three secondary sources of the same isotope to validate detector linearity and stability; however, single point calibrations using secondary sources where detectors are inherently linear are acceptable. In addition, the detectors are provided with check sources which can be used to indicate functional operability. Tests, functional checks and calibrations are performed periodically in accordance with Technical Specification requirements and operating procedures. 11.4-23 SGS-UFSAR Revision 28 May 22, 2015