ML18033A862
| ML18033A862 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry  |
| Issue date: | 08/04/1989 |
| From: | TENNESSEE VALLEY AUTHORITY |
| To: | |
| Shared Package | |
| ML18033A861 | List: |
| References | |
| TVA-BFN-TS-273, NUDOCS 8908090182 | |
| Download: ML18033A862 (18) | |
Text
ENCLOSURE I PROPOSL'D TECINICAL SPECIFICATIONS REVISIONS BROlR)S FERRY NUCLEAR PLANT (TVA BFN TS 273)8908090i82 890804 PDR ADOCK 05000259 PDC 3.7/0.7 COHTAIHHEHT SYSTEHS LIHITING CONDITIONS FOR OPERATION SURVEILLANCE REQUIREHFNTS 3.7.F.Primar Containment Pur e~ms tsm<.7.F.Primar Containment Pur e~Ss tsm 1.The primary containment shall be normally vented and purped through the primary containment purpe system.1.At least once every 18 months, the pressure dx.op acro-s the combined HEPA filters and charcoal adsorbex'anks shall be demonstrated to be less than 8.5 inches of water at system desipn flow rate (+10'/).2.a.The results oE the in-place cold DOP and halopenated hydrocarbon tests at desipn flows on HEPA filters and charcoal adsorber banks shall show>99Vo DOP removal and>99%halopenatcd hydrocarbon x.emoval when tested in accordance with ANSI H510-1975.
2~a~The tests and sample analysis of Specification 3.7.F.2 shall be perEormed at least once per operatinp cycle or once evex..y 18 months, whichever occurs Eix.st or after 720 hours0.00833 days <br />0.2 hours <br />0.00119 weeks <br />2.7396e-4 months <br /> of system operation and following, sipnificant paintlnp, fire, or chemical release in any ventilation zone communicating with the system.b.The results of laboratory carbon sample analysis shall show>857m x;adioactive methyl iodide removal when tested in accordance with ASTH D3803 (130 C 951m R.H.).b.Cold DOP testing shall be performed after each complete or partial replacement of the HEPA filter bank or aEter any structural maintenance on the system housinp.c.System Elow rate shall be shown to be within+101m of desipn Elow when tested in accordance with ANSI H510-1975.Cs Halopenated hydrocarbon testing shall be performed after each complete or partial replacement oE the charcoal adsorber bank or after any structural maintenance on the system housinp.BI'H Unit 1 3.7//i.7-21
3'.7/4.7 BASES (Cont'd)Opex.'ation of the system fox;10 hours1.157407e-4 days <br />0.00278 hours <br />1.653439e-5 weeks <br />3.805e-6 months <br /> evevy month will demonstz.ate opevability of the.filtez.s and adsovbor system and eomove excessive moisture built up on t1le adsoxbex.If-ignificant painting, fice or chemical z.eleaso occurs such that the 11EPA filter ox;charcoal adsoeber could become contaminated fvom the fumes, chemicals ox.Eoeeign materials, the same tests and sample analysis shall be performed as required for operational use.The determination oE significance shall be made by the opeeator on duty at the time of the incident.Kzxowlodgeable staff mombex.s..hould be consulted prior to making, this determination.
Demonsteation of the automatic initiation capability is necessary to assuve system perfonnance capability.
3.7.F/4.7.F Peimae Containment Pur e S stem The primary containment purge system is designed to px.ovide Uxe exhaust path to purge and vontilate the primary containment system.The exhaust from the pvimary containment is first px;ocessod by a filtev tvain assembly and then channeled theough the reactoe building roof exhaust: system.During power operation, the pvimary containment, purge and ventilation system is isolated from the primaz;y contaixxment by two isolation valves in series.However, the peimary containment purge and ventilation system may be used as part of the inex.ting/deinerting process for 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> following placing the mode switch in Uxe RUH position ov 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> priox to shutdown.11FPA (high efficiency pavticulate aie)filters aee installed before the chax;coal adsorbees Eollowod by a centrifugal Ean.The in-place test results should indicate a leak tightness of the system housing oE not less than 99-porcent and a 1$EPA efficiency of at least 99-percent removal of DOP particulates.
The laboratory carbon sample tost results should indicate a x..adioactlve meUzyl iodide eemoval efficiency of at lea t 85-pez..cent.
Operation of the fan..significantly differont from the design Elow will change Uxe eomoval efficiency of the 11EPA filters and charcoal adsoebevs.
If the peimaey containment purge system is unavailable, the standby gas tveatment system may be used for ventilation and purging thvough operatoe FC0-64-36.
The 2 inch vent line using valve FCV 84-20 may bo u"ed to perform containment peessuee control during reactor opeeation.
This path limits the flow to the standby gas teeatment system to 100 SCFH.If tho system is found to be inoperable, the Standby Gas Treatment System may be used to purge the containmont.
Pres..ure dx.op acro..s the combined HEPA f ilters and c1xarcoal adsovbevs oE less than 8.5 inches of water at the system design flow rate will indicate that the filtoes and adsorbex.s ax..e not clogged by excessive amounts oE foreign matter.Pee...ux;e dvop should bo dotoemixxed at least once per opexating cycle to show-systom peefonxance capability.
BFH Unit.1 3.7/4.7-52 The frequency of tests and sample analysis are necessax.y to show that the HEPA filtex;and charcoal ad..orbers can perform as evaluated.
Tests of the charcoal adsorbers with halogenated hydrocarbon shall be perfox;med in accordance with USAFC Report-1082.
Iodine removal eEficiency tests shall follow ASTH D3803.The charcoal adsox;ber eEficiency test procedures should allow for the removal of one adsorber tray, emptying of one bed from the tray, mixing the adsorbent thoroughly and obtaining at least two samples.Hach:ample should be at.least two inches in diameter and a length equal to the thickxxe s oE the bed.If test results are unacceptable, all adsorbent in the system"hall be replaced with an adsorbent qualified according to Table 1 of Regulatory Guide 1.52.The replacement tx.'ay Eor the adsorber tray removed for the test should meet the same adsorbent quality.Tests oE the HFPA filters with DOP aerosol.:.hall be performed in accordance to ANSI N510-1975.
Any HEPA filtex.Eound deEective shall be replaced with filters qualified pursuant to Regulatory Position C.3.d of Regulatory Guide 1.52.If..ignificant painting, fire, or chemical release occurs such that the HFPA filtex..ox;charcoal adsox..ber could become contaminated from the fumes, chemicals or foreign materials, the same tests and sample analysis shall be performed as required for opex.ational use.The determination of significance
- hall be made by the operator on duty at the time of.the incident.Knowledgeable staff members should be consulted prior to making this determination.
BPN Unit 1 3.7/4.7-53
3.7/4.7 COHTAIHNEHT SYSTEHS LIHITIHG CONDITIONS FOR OPERATION SURVEILLANCE REQUIREHEHTS 3.7.F.Primae Containment Pur e~Ss tsm 4.7.F.Primar Containment Pur e~Sstsm 1.The primary containment shall be normally vented and purged through the primary containment purge system.1.At least once every 18 months, the pressure drop across the combined HEPA filters and charcoal adsorber banks shall be demonstrated to be less than 8.5 inches of water at system design flow rate (+10%).2.a.The re..ult of the in-place cold DOP and halogenated hydrocarbon tests at design flow: on HEPA filters and charcoal adsorber banks shall..how>99%DOP removal and>99%halogenated hydrocarbon removal when tested in accordance with ANSI N510-1975.
2 s a~The tests and sample analysis of Specification 3.7.F.2 shall be performed at least once per.operating cycle or once every 18 months, whichever occurs first or after 720 hours0.00833 days <br />0.2 hours <br />0.00119 weeks <br />2.7396e-4 months <br /> of system operation and following significant painting, fire, or chemical release in any ventilation zone communicating with the system.b.The results of laboratory carbon..ample analysis shall show>85%radioactive methyl iodide removal when tested in accordance with ASTH D3803 (130 C 95%R.ll.).Cold DOP testing shall be performed after each complete or partial replacement of the HEPA filter bank or after any structural maintenance on the system housing.c.System flow rate..hall be shown to be within+10%of design flow when tested in accordance with ANSI H510-1975 c~Halogenated hydrocarbon testing shall be performed after each complete or partial replacement of the charcoal adsorber bank or after any structural maintenance on the system housing.BFH Unit.2 3.7/4.7-21 Operation of the-ystem for 10 hours1.157407e-4 days <br />0.00278 hours <br />1.653439e-5 weeks <br />3.805e-6 months <br /> every month will demonstrate operability of the filters and ad-orber-ystem and remove excessive moisture built up on the adsorbex;.
If..ignificant painting, fire or chemical x;elease occux.s-uch that the HEPA filter or chax.coal adsox.ber could become contaminated Erom the fumes, chemicals or foreign materials, the same tests and sample analysis shall be performed as required for operational use.The determination of significance shall be.made by the opex.ator on duty at the time of the incident.Knowledgeable staEf membex.s should be consulted prior to making this d etex.minat ioll~Demonstration of the automatic initiation capability is necessary to assure ystem performance capability.
3.7.F/4.7.F Primar Containment Pur e S stem The primary containment purge system is designed to provide the exhaust path to purge and ventilate the primary containment system.The exhaust from the primary contaixxment is first processed by a filter train assembly and then channeled through the reactor building rooE exhaust system.During power operation, the primary containment purge and ventilation system is isolated from the primary containment by two isolation valves in series.lkowever, the primary contaixxment purge and ventilation system may be u"ed as part of the ixxerting/deinerting process for 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> following placing the mode switch in the RUN position or 24 houx.s prior to shutdown.HEPA (high efficiency particulate air)filters are installed before the charcoal adsorber..
followed by a centrifugal fan.The in-place test results should indicate a leak tightne..s oE the system housing of not less than 99-percent and a l(EPA efficiency of at least 99-percent removal of DOP pax.ticulates.
The laboratory carbon.-ample test results should indicate a radioactive methyl iodide x;emoval efficiency of at least 85-percent.
Opex;ation of the fans.,ignificantly different from the design flow will change the removal efficiency of the lTEPA filters and chax.coal adsorbers.
If the primary containment purge system is unavailable, the standby gas treatment system may be u-ed for ventilation and purging through operator FC0-64-36.
The 2 inch vent line using valve FCV-84-20 may bc used to perform containment pressure control during reactor operation.
This path limits the flow to the standby gas treatment system to 100 SCFH.If the system is found to be inoperable, the Standby Gas Treatment System may be used to purge the containment.
Pres-ure drop acx.oss the combined HFPA filters and charcoal adsorbers of less than 8.5 inches of water at the system design flow rate will indicate that the filters and adsorbers are not clogged by excessive amount oE foreign matter.Pressure drop should be determined at least once per operating cycle to show system performance capability.
BFH Uxxit 2 3'/4.7-52 3x7/4.7 BASES (Cont'd)The frequency of tests and'::ample analysis are necessary to show Uxat the HEPA filters and charcoal adsorbex.s can perEorm as evaluated.
Tests oE the chax.coal ad-orbers with halopenated hydrocarbon shall be performed in accordance with USAEC Report-1082.
Iodine removal efEiciency tests shall follow ASTH D3803.The chat.'coal adsox.'ber efficiency test procedures should allow Eor the removal oE one adsox.ber tray, emptying oE one bed from the tray, mixinp Uxe adsorbent thoroughly and obtaininp at least two samples.Each sample should be at least two inches in diametex.and a lenp,th equal to the Uxickness of the bed.If test re..ults are unacceptable, all adsorbent in the system shall be replaced with an adsorbent qualified according, to Table 1 of Regulatory Guide 1.52.The replacement tray for the adsorber tray removed for the test should meet the same adsorbent quality.Tests oE the HRPA filters with DOP aerosol shall be performed in accordance to ANSI H510-1975.
Any HEPA Eilter found defective shall be replaced with filters qualified pursuant to Repulatory Position C.3.d of Regulatory Guide 1.52.'f significant paintingfire, or chemical release occurs such that the HEPA filter or charcoal adsorber could become contaminated from the fumes, chemicals or foreign materials, the same tests and sample analysis shall be performed as required for operational use.The determination of significance shall be made by the operator on, duty at the time of the incident,.
Knowledgeable stafE members should be consulted prior to making this determination.
BFH Unit 2 3.7//i.7-53
3.7/4.7 COHTAIHHENT SYSTEHS LIHITIHG CONDITIONS FOR OPERATION SURVEILLANCE REQVIRFHENTS 3.7.F.Primae Containment Pur e~sstsm 4.7.F.Primar Containment Pur e~Sstsm 1.The primary containment shall be normally vented and purged through the primary containment purge system.1.At least once every 18 months, the pressure drop across the combined NEPA filters and charcoal adsorber banks shall be demonstrated.to be less than 8.5 inches of water at system design flow rate (+101).2.a;The results of the in-place cold DOP and halogenated hydrocarbon tests at design flows on 1$EPA filter.s and charcoal ad.orber banks shall show>99%DOP removal and>99'Fo halogenated
'hydrocarbon removal when te ted in accordance with ANSI H510-1975.
2.a.The tests and sample analysis of Specification 3.7.F.2 shall be performed at least once per operating cycle or once every 18 months, whichever occurs first or after 720 hours0.00833 days <br />0.2 hours <br />0.00119 weeks <br />2.7396e-4 months <br /> of system operation and following significant painting, fire, or chemical release in any ventilation zone communicating with the system.b.The results of laboratory carbon.-ample analy..is shall show>851.radioactive methyl iodide removal when tested in accordance with ASTH D3803 (130 C 951m R N)b.Cold DOP testing shall be performed after each complete or partial replacement of the HFPA filter bank or after any structural maintenance on the system housing.c.System flow rate"hall be shown to be within+10'f.of design flow when tested in accordance with ANSI H510-1975.c Halog~nated hydrocarbon testing shall be performed after each complete or partial replacement of the charcoal adsorber bank or after any structural maintenance on the system housing.BFH Unit, 3 3.7//i.7-21 3'.7/4.7 BASES (Cont'd)Operation of the sy-tern For 10 hours1.157407e-4 days <br />0.00278 hours <br />1.653439e-5 weeks <br />3.805e-6 months <br /> evexy month will demonstvate opex;ability oE the filter..and adsorber system and remove excessive moistuve built up on the adsorbev.If sipnificaxxt paintinp, Eir'e or chemical release occurs-uch that thc HEPA filtex;or charcoal adsoxber could become contaminated fvom the fumes, chemicals ov fox.eign materials, the same tests and sample anal.ysis shall be pevformed as required fov operational use.The determination of sipnificance"hall be made by the opex;atov on duty at the time of the incident.Knowledgeable-taff membex.s should be consulted pvior to making this determination Demonstration of the automatic initiation capability is necessary to assuve system perfonxance capability.
3.7.F/4.7.F Px.imax;Containment Pur e.S stem The Primary Containment Purpe System is designed to px;ovide the exhaust path to purge and ventilate the primary containment system.The exhaust from.the px.imary containment i-first processed by a filter train assembly and then channeled through the x.eactov buildinp roof exhaust system.Duving power opex;ation, the" primary containment purge and ventilation system is isolated Erom the px.imary containment by two isolation valves in series.However, the primary containment purpe and ventilation system may be used as part of the inerting/deinex;tinp process fov 24 houvs following placing the mode switch in the RUM position or 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> prior to shutdown.HEPA (hiph efficiency particulate air)Eiltexs are installed beEore the charcoal adsorbers followed by a centrifupal fan.The in-place test results should indicate a leak tiphtness oE the system housinp of not less than 99-percent and a HEPA efficiency of at least 99-percent removal oE DOP particulates.
The laboratovy carbon sample test results should indicate a vadioactive methyl iodide x.emoval efficiency of at least 85-percent.
Opex;ation of the fans significantly difEerent from the desipn flow will change the removal efficiency of the HEPA Eiltevs and charcoal adsorbex.s.
If the primary containment purpe system is unavailablo, the standby pas treatment system may be used for ventilation and purging throuph operator FCO-64-36.
The 2 inch vent line usinp valve FCV-84-20 may be used to perform containment pressuve control duving vcactov opevation.
This path Limits the flow to the standby pas treatment system to 100 SCFH.If the system is found to be inoperable, the Standby Gas Treatment System may be used to purpe tlxe containment.
Pvessure drop across the combined HEPA filtevs and charcoal adsorbex.s of less than 8.5 inches of watev at the system desipn flow r'ate wil.l indicate that the filters and adsovbex;s are not clopped by excessive amounts oE foreign mattev.Pvessure dvop should be determined at least once per operating cycle to show=system pevformance capabil.ity.
BFH Uxxit 3 3.7/4.7-50 3'.7/4.7 BASH'S (Cont'd)The frequency of tests and sample analysis are necessax;y to show that the HEPA filters and charcoal adsorbex;s can perform as evaluated.
Tests of the chax;coal adsorbers with halogenated hydx;ocarbon-hall be performed in accordance with USMC Report-1082.
Iodine rc moval efficiency tests shall follow AS'3803.The charcoal adsorber efficiency test px;ocedures should allow for the removal of one adsorber tx.ay, emptying of one bed from the tray, mixixxg the adsorbent thox;oughly and obtaining, at least two samples.Each"ample should be at least two inches in diameter and a length equal to the thickness of the bed.If test results are unacceptable, all adsorbent in the system shall be replaced with an adsorbent qualified according, to Table 1 of Regulatory Guide 1.52.The replacement tray for the adsorber tray removed for the test should meet the same adsorbent quality.Tests of the HEPA filtex.s with DOP aerosol shall be performed in accordance to ANSI N510-1975.
Any HEPA filters found defective.
shall be replaced with filtex.s qualified pursuant to Regulatory Position C.3.d of Regulatory Guide 1.52." If significant painting, fire, or chemical release occurs such that the HEPA filter ox;charcoal adsorber could become contaminated from the fumes, chemicals or foreign materials, the-arne tests and sample analysis shall be perfox;med as required for operational use.The determination of significance"hall be made by the operator on duty at the time of the incident.Knowledgeable staff members should be consulted prior to making, this detex:mixlatioxl BFN Unit 3 3.7/4.7-51 FHCLOSURE 2 DESCRIPTION AHD JUSTIFICATION BROMNS FERRX NUCLEAR PLANT (BFH)Reason for Change BFN unit 1, 2, and 3 Technical Specification (TS)3.7.F.1 and Bases Section 3.7.F for Primary Containment Purge System are being revised to better reflect the intended operation of venting the primary containment during operation.
Description and Justif ication for the Proposed Change The exi ting TS 3.7.F.1 currently reads: The primary containment shall be normally vented and purged through the primary containment purge system.The standby gas treatment system may be used when printery containment purge systems is inoperable.
Revise TS 3.7.F.1 to iead as follows: The primary containment shall be normally vented and purged through the primary containment purge system.Revise TS Bases Section 3.7.F Revi"e Base Section 3.7.F in accordance with Enclosure 1 to this TS change re/Vest+Justification for proposed change The primary containment purge system is designed to provide the exhaust path to purge and ventilate the primary containment system.The primary containment purge system is part of the primary containment system and provides the capability to inert the containment with nitrogen and to purge or ventilate the containment with air.Portions of the primary containment system and the containment atmosphere dilution (CAD)system combined to form a path which is used to provide pressure control for the primary containment.
In addition to providing the capabilities stated above, the CAD system also helps limit the release of fission products to the reactor building so that offsite doses are maintained below the limits specified in 10 CFR 100 by maintaining pressure boundary integrity.
During power operation, the primary containment purge and ventilation system is normally isolated from the primary containment by two isolation valves,.in series.The exhaust from the primary containment is first proce-sed by a filter train assembly and then channeled through the reactor building roof exhaust system.Releases through the exhaust path are monitored by a radiation monitor.This radiation monitor has a set point, that if reached, would provide a group 6 isolation signal resulting in the open purge valve to close.This isolation function is verified in accordance with BFN TS Table 3.7.A.The operation of the primary containment purge and ventilation system is limited up to 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> for the inerting/deinerting process following placing the reactor mode switch in the RUH po-ition or for up to 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> prior to shutdown.
The current TS stated that the standby gas treatment sy tem (SBGTS)may be used when the primary containment purge system is inoperable.
This statement implies that the 18 inch vent path to the SBGTS can be used when the primax.y containment purge system is inoperable.
In contrast to 18 inch primary containment purge path, the other vent capabilities are through two small 2 inch lines that vent through the SBGTS.These 2 inch lines aie used for primax.'y containment pressure control.Thi pressure control function may be used during reactor heatup or xxozml reactor operation in order to maintain the pressure range inside the drywell between 1.2 and 1.6 psig.Px.essure increase in the drywell is a re-ult of thermal expansion of gases.For maintaining primary containment pressure control during power opex;ation, a 2 inch vent path using a remote-manual operated valve (FCV-84-20) will be u..ed.This path goes through the SBGTS and is limited to 100 SCFH.From the SBGTS, the venting process goes through the plant stack.There are radiation monitors located in this vent path to monitor any such releases.Administxative procedures required that the FVCV-84-20 valve only be used during power operation.
Valve FCV-84-20 receives a group 6 i-olation sigxxal and is capable of closing within 10 seconds of receiving the signal.This is verified in accordance with TS table 3.7.A, Px;imax;y Containment Isolation Valves.In addition, the containment isolation valves (FCV-64-31 from the drywell and FCV-64-34 from the torus)ax.'e redundant primary containment isolation valves for FCV-84-20 and will close in 5 seconds following the receipt of an isolation signal.All of these valves are designed to close against the drywell design pressure of 56 psig.Therefore, the valves are capable of closing in LOCA conditions, and the x;adioactive release due to these valves being open for pressure control at the initiation of a LOCA within the 10 CFR 100 limits.
EHCLOSURL.
3 DETERHINATION OF'HO SIGNIFICANT HAZARDS CONSIDFRATION BROGANS FERRY NUCLEAR PLANT (BFN)DESCRIPTION OF PROPOSED TS mEND~ENT BFH unit 1, 2, and 3 technical specification (TS)3.7.F.1 and its Bases section, are being revised to clarify and more accurately describe the operation of the.Primary Containment Purge System and BFN.BASIS FOR PROPOSED NO SIGHIFICAHT HAZARDS CONSIDERATION DFTERHNATION HRC has provided standards for determining whether a significant hazards con..ideration exists as stated in 10 CFR 50.92(c).A proposed amendment to an operating license involves no significant hazards consideration if operation of the facility in accordance with the proposed amendment would not 1)involve a significant increase in the probability or consequences of an accident previously evaluated, or 2)create the possibility of a new or different kind of accident from any accident previously evaluated, or 3)involve a significant reduction in a margin of afety.1.The proposed change does not involve a significant increase in the probability or consequences of an accident previously evaluated.
The purpo-e of this proposed change is to clarify and more accurately describe the method in which BFN operates the Primary Containment Purge System.This change properly instructs the operators to use the 18 inch primary containment purge and ventilation system for deinerting/inerting proce..s for up to 2/i hours after placing the reactor mode switch in the RUH position or for up to 2/i hours prior to reactor shutdown.This is the normal operation of the system.In the event the primary containment purge and ventilation system is unavailable, the 18 inch vent line through the standby gas treatment system (SBGTS)may be used as a backup with the same time restrictions.
The two containment isolation valves associated with the primary containment purge and ventilation exhaust system receive a group 6 isolation signal.The alternate 18 inch line going through the SBGTS will also be isolated when these two valves are closed.Both these valve are tested in accordance with the primary containment isolation valve surveillance TS 4.7.D.l.The only other vent path from primary containment are the two containment Atmospheric Dilution (CAD)Valves.These 2 inch lines are used to maintain primary containment pressure control.Administrative procedure only allow the use of the vent path through FCV-8/i-20.
Again, this valve receives a group 6 isolation signal which overrides the remote-manual handswitch and closes the valve.This isolation function is tested in accordance with TS/l.7.D.
e Page 2 oE 2 This change does not involve any physical alteration of the containment, design function of any existing equipment, or add any new equipment to BFH, The operating conditions and analysis in the BFH Final Safety Analysi-Report (FSAR)are till applicable and will not change as a result of this amendment.
This change only provides additional clarification and makes the TS more consistent with the operations of the plant.Based on the above, this proposed change does not involve a significant increase in the probability or consequences of an accident previously evaluated.
The proposed change does not create the possibility of a new or difEerent kind of accident from any accident previously evaluated.
The change does not add any new equipment to the plant or require any existing equipment to be operated in a diEferent manner from which it was designed to operate.Since a new failure mode is not introduced by the change, a new or different kind of accident could not result.3~The proposed change does not involve a signiEicant reduction in a margin of safety.The proposed change does not result in a reduction of acceptance criteria where the potential for significant structural integrity degradation exists.Since the primary containment purge and ventilation system is only allowed to open for 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> after the reactor is place in the, RUH mode and for up to 2~<hours prior to reactor shutdown the probability for: a loss of coolant accident (LOCA)during this time is minimal.If a LOCA were to occur, the isolation valves would receive a group 6 isolation signal therefore, closing the valves.The only other vent path to the outside environment is through the CAD valves.The dose consequences through an open pre.sure control path during a LOCA would be below tho 10 CFR 100 limits.The pressure control valve (FCV-8<<-20) also receives a group 6 isolation signal and is capable of closing within 10 seconds of the isolation signal.Since thi" proposed TS only provides clarification and the initial design requir<=ments are not altered, there is no reduction in the margin of-afety at BFH.