ML20154C158
| ML20154C158 | |
| Person / Time | |
|---|---|
| Site: | Crystal River  |
| Issue date: | 09/30/1998 |
| From: | FLORIDA POWER CORP. |
| To: | |
| Shared Package | |
| ML20154C135 | List: |
| References | |
| NUDOCS 9810060176 | |
| Download: ML20154C158 (5) | |
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d RCS Leakage Detection Instrumentation B 3.4.14 B-3.4' REACTOR COOLANT SYSTEM (RCS)
B 3.4.14'.RCS Leakage Detection Instrumentation BASES BACKGROUND 10 CFR 50, Appendix A, GDC 30, (Ref. 1) requires means be provided for detecting and, to the extent practical, identifying the location of the source of RCS LEAKAGE.
Regulatory Guide 1.45 (Ref. 2) describes acceptable methods for selecting leakage detection systems.
Leakage detection systems must have the capability to detect ;
reactor coolant pressure boundary (RCPB) degradation as soon '
after occurrence as practical to minimize the potential for propagation to a gross failure. Thus, an early indication or warning signal is necessary to permit proper evaluation of all unidentified LEAKAGE.
1 The containment' sump collects unidentified LEAKAGE and is instrumented to alarm on increasing level and has the capability to detect a leakage rate of I gpm in.less than 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br />. This sensitivity is acceptable for detecting increases in unidentified LEAKAGE.
The reactor coolant contains radioactivity that, when released to the containment, can be detected by radiation monitoring instrumentation. Reactor coolant radioactivity levels will be low during initial reactor startup and for a few weeks thereafter until activated corrosion products have 1 been formed and fission products appear from fuel' element cladding contamination or cladding defects. Instrument sensitivities of 10 pCi/cc radioactivity for particulate monitoring and of 10- pCi/cc radioactivity for gaseous monitoring are adequate for these leakage detection systems.
The pasticulateJmonitorihg ' channel detector is capable of detectinga' change"in RCS le~ak~ rate of I gpm within one hour en both the pcrticuhte end gesecus rcdiccctivity monitoring systems, based on Rb SS cnd activity levels assumed in the environmental report (0.1% failed fuel). Thel predominant nucl ide J off detection i fo r l thef p arti c ul ate"ch annel f i ss Rb-88h The -gaseous;.channeltrequiresisignificantly. more time::to detect!the same1changesin1RCS: leak:ratel(approximatelyjl4 hours)! eThisiisidue toLthe relatively longghalf-life;of3its ' ~
predomin.sntlnuclideiofdetect. ion,"Xe-1330 Other installed instrumentation such as RB pressure and Containment Cooling Fan condensate flow also indicate leakage into containment. These are potentially valuable (continued)
Crystal River Unit 3 B 3.4-65 Revision No. W 9810060176 980930 PDR ADOCK 05000302 p ,PDR
N'"5'I "; 10 FINAL SAFETYANALYSIS REPORT Chapter 4 REACTOR COOLANTSYSTESi Page: 18 of 18 i 4.2.3.6.3 Water Quality Industry experience and test programs have periodically shown the need for revising reactor coolant quality specifications. Reactor coolant specifications are revised to further minimize corrosion product activation and to promote long-term structural integrity of steam generator tubing and other components. Plant specific chemistry specifications are revised as needed based en site specific and industry experience and test programs. Plant chemistry specifications conform to the ITS and are described in plant procedures. Chemistry specifications will continue to be improved as more is learned from industry experience and testing. Reactor coolant quality specifications are listed in Table 4-10. The solids content of the reactor coolant is maintained below the design level by minimizing corrosion through chemistry control and by continuous purification of the letdown stream of reactor coolant using the letdown filter and purification demineralizer of the MU system. A hydrogen overpressure is maintained in the makeup tank to ensure that a predetermined amount of dissolved hydrogen remains in the 1 reactor coolant to chemically combine with the oxygen produced by radiolysis of the water.
4.2.3.7 Flow Measurement l
Reactor coolant flow rate is measured for each heat transport loop by a flow tube welded into the reactor outlet pipe.
The power / flow monitor of the Reactor Protection system (RPS) utilizes this flow measurement to prevent reactor power from exceeding a permissible level for the measured flow. This is discussed in further detail in Section 7.3.2. ;
4.2.3.8 Leak Detection I The entire RC system is located within the secondary shielding and is inaccessible during reactor operation. All RC system leakage drains to the RB sump. All RC system leakage to the RB atmosphere will be in the fomi of fluid and vapor. The fluid will drain to the RB sump while the vapor will be condensed in the RB coolers and drain to the RB sump via a drain line from the RB cooler.
The RB air sample line radiation monitor (RM-A6) consists of a particulate measuring channel with a range of I x 10~" to 1 x 104 pCi/cc (Cs-137) and a gaseous measuring channel with a range of I x 104 to 1 x 10 2 pCi/cc (Kr-85). RM-A6 contains two parallel connected particulate / iodine prefilters, an isokinetic sampler and two pump l assemblies. The two pumps are powered from alternate power sources such that a loss-of-power to the running ]
pump will automatically start the standby pump. The filter activity is counted and displayed in the control room on '
the radiation monitor panel module. A high radiation count rate initiates an indicating light on the radiation monitoring panel module and sounds an alarm in the control room. N npem " ^ 6 " rue 'h2t " "' .C ,
y 'em #!!y 'e e!: 2 red !" e e : e e"!2! ere~ (0 '" f2!!ed fue't 2 er;;c : D.C rye " '? r te of ' j 7 :ii n e &, -,g m an:- t e. .
. ThspitisulatiWMit6risistissiiispable 6f detectinff6lisrigsin RCS I leuiUse'6f 6issisissithis'6nsh tir,' based bn' activity levels assumed in the Enviromnental Report (0.1% failed i fuel)dThe predominant nuclide of detection' for the particulate' channel is' Rb-88M'Ihe gaseous channel require 5 Mgnificantlyfmom time lto detectithe same ' change in RCS leak rate'(approximatelyXhours).1]hisjs,dueltolthe relatively_long. half-lik ofits predominant nuclide of detection lXe-133; The sample point for RM-A6 is located within duct work for air handling fan AHF-3B near the 190 ft elevation of the RB. An additional sample point is installed within the existing sample line and is located near the 160 ft elevation of the RB. - The additional sample point affords flexibility in plant operation if fan AHF-3B were to fait during normal operation. Repairs to AllF-3B could then be performed during the next available outage rather than during power operation. The additional sample point was analyzed to assure that adequate air l'ow is available to
FLORIDA POWER CORPORATION CRYSTAL RIVER UNIT 3 DOCKET NO. 50-302/ LICENSE NO. DPR-72 ATTACIIMENT C LICENSE AMENDMENT REQUEST #238, REVISION 0 Revision to Licensing Basis for Reactor Coolant System Leakage Detection Instrumentation Proposed Revisions to Improved Technical Specification Bases and Final Safety Analysis Report in Revision Bar Format l
I i
l
RCS Leakage Detection Instrumentation
, B 3.4.14 8 3.4 REACTOR COOLANT SYSTEM (RCS)
B 3.4.14' RCS Leakage Detection Instrumentation BASES BACKGROUND 10 CFR 50, Appendix A, GDC 30, (Ref.1) requires means be provided for detecting and, to the extent practical, identifying the locatior ,f the source of RCS LEAKAGE.
Regulatory Guide 1.45 (Ref. 2) describes acceptible methods for selecting leakage detection systems.
Leakage datection systems must have the capability to detect reactor coolant pressure boundary (RCPB) degradation as soon after occurrence as practical to minimize the potential for propagation to a gross failure. Thus, an early indication or warning signal is necessary to permit proper avaluation of all unidentified LEAKAGE.
The containment sump collects unidentified LEAKAGE and is instrumented to alarm on increasing level and has the capability to detect a leakage rate of 1 gpm in less than 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br />. This sensitivity is acceptable fcr detecting increases in unidentified LEAKAGE.
The reactor coolant contains radicactivity that, when released to the containment, can be detected by radiation monitoring instrumentation. Reactor coolant radioactivity levels will be low during initial reactor startup and for a few weeks thereafter until activated corrosior, products have been formed and fission products appear from fuel element cladding contaminatipn or cladding defects. Instrument sensitivities of 10' yCi/cc radioactivity for particulate monitoring and of 10'g pCi/cc radioactivity for gaseous monitoring are adequate for these leakage detect *on systems.
The particulate monitoring channel is capable of detecting a change in RCS leak rate of 1 gpm within one hour based on activity levels assumed in the environmental report (0.1%
failed fuel). The predominant nuclide of detection for the particulate channel is Rb-88 The gaseous channel requires significantly more time to d tect the same change in RCS leak rate (approximately 14 nours). This is due to the relatively long half-life. of its predominant nuclide of detection, Xc-133.
Other installed instrumentation such as RB pressure and Containment Cooling Fan condensate flow also indicate leakage into containment. These are potentially valuable (continued)
Crystal River Unit 3 8 3.4-65 Amendment No.
1
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l N'"I'I*"; 15 l FINAL SAFETYANALYSIS REPORT Chapter 4
~
REACTOR COOLANTSYSTEM Page: 18 of 18 l l
4.2.3.6.3 Water Quality Industry experience and test programs have periodically shown the need for revising reactor coolant quality specifications. Reactor coolant specifications are revised to further minimize corrosion product activation and to promote long-term structural integrity of steam generr'or tubing and other components. Plant specific chemistry specifications are revised as needed based on site specific and industry experience and test programs. Plant chemistry specifications conform to the ITS and are described in plant procedures. Chemistry specifications will continue to be improved as more is leamed from industry experience and testing. Reactor coolant quality specifications are listed in Table 4-10. The solids content of the teactor coolant is maintained below the design level by minimizing corrosion through chemistry control and by continuous purification of the letdown stream of reactor coolant using the letdown filter and purification demineralizer of the MU system. A hydrogen overpressure is maintained in the makeup tank to ensure that a predetermined amount of dissolved hydrogen remains in the reactor coolant to chemically combine with the oxygen produced by radiolysis of the water.
4.2.3.7 Flow Measurement Reactor coolant flow rate is measured for each heat transport loop by a flow tube welded into the reactor outlet pipe.
The power / flow monitor of the Reactor Protection system (RPS) utilizes this flow measurement to prevent reactor ;
power from exceeding a permissible level for the measured flow. This is discussed in further detail in Section 7.3.2.
4.2.3.8 Leak Detection l
The entire RC system is located v ithin the secondary shielding and is inaccessible during reactor operation. All RC i
, system leakage drains to the RB sump. All RC system leakage to the RB atmosphere will be in the form of fluid I
and vapor. The fluid will drain to the RB sump while the vapor will be condensed in the RB coolers and drain to l
the RB sump via a drain line from the RB cooler.
The RB air sample line radiation monitor (RM-A6) consists of a pvticulate measuring channel with a range of l 1 x 10~" to 1 x 104 pCi/cc (Cs-137) and a gaseous measuring channel with a range of I x 10-* to 1 x 10-2 pCi/cc 1 (Kr-85). RM-A6 contains two parallel connected particulate / iodine prefilters, an isokinetic sampler and two pump assemblies. The two pumps are powered from alternate power sources such that a !oss-of-power to the running pump will automatically start the standby pump. The filter activity is counted and displayed in the control room u !
the radiation monitor panel module. A high radiation count rate initiates an indicating light on the radiation monitoring panel module and sounds an alarm in the control room. The particulate monitoring channel is capable of detecting a change in RCS leak rate of one gpm within one hour, based on activity levels assumed in the Environmental Report (0.1% failed fuel). The predominant nuclide of detection for the particulate channel is Rb-88. The gaseous channel requires significantly more time to detect the same change in RCS leak rate (approximately 14 hours1.62037e-4 days <br />0.00389 hours <br />2.314815e-5 weeks <br />5.327e-6 months <br />). This is due to the relatively long half-life of its predominant nuclide of detection, Xe-133. i l l The sample point for RM-A6 is located within duct work for air handling fan AIIF-3B near the 190 ft elevation of l the RB. An additional sample point is installed within the existing sample line and is located near the 160 fl elevation of the RB. The additional sample point affords flexibility in plant operation if fan AliF-3B were to fail during normal operation. Repairs to AIIF-3B could then be performed during the next available outage rather than during power operation. He additional sample point was analyzed to assure that adequate air flow is available to obtain a representative sample of the RB atmosphere and is capable of providing a high radiation alann within one hour for an event as previously described.
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