NRC Generic Letter 1989-16
UNITED STATESNUCLEAR REGULATORY COMMISSIONWASHINGTON, D. C. 20555September 1, 1989TO: ALL HOLDERS OF OPERATING LICENSES FOR NUCLEAR POWER REACTORSWITH MARK I CONTAINMENTS
SUBJECT: INSTALLATION OF A HARDENED WETWELL VENT (GENERIC LETTER 89-16)As a part of a comprehensive plan for closing severe accident issues, thestaff undertook a program to determine if any actions should be taken, ona generic basis, to reduce the vulnerability of BWR Mark I containments tosevere accident challenges. At the conclusion of the Mark I ContainmentPerformance Improvement Program, the staff identified a number of plantmodifications that substantially enhance the plants' capability to bothprevent and mitigate the consequences of severe accidents. The improvementsthat were recommended include (1) Improved hardened wetwell vent capability,(2 'improved reactor pressure vessel depressurization system reliability,(3 an alternative water supply to the reactor vessel and drywell sprays, and(4 updated emergency procedures and training. The staff as part of thateffort also evaluated various mechanisms for implementing of these plantimprovements so that the licensee and the staff efforts would result in acoordinated coherent approach to resolution of severe accident issues inaccordance with the Commission's severe accident policy.After considering the proposed Mark I Containment Performance Program(described in SECY 89-017, January 1989), the Commission directed the staffto pursue Mark I enhancements on a plant-specific basis in order to accountfor possible unique design differences that may bear on the necessity andnature of specific safety improvements. Accordingly, the Commission concludedthat the recommended safety improvements, with one exception, that is,hardened wetwell vent capability, should be evaluated by licensees as part ofthe Individual Plant Examination (IPE) Program. With regard to the recommendedplant improvement dealing with hardened vent capability, the Commission, inrecognition of the circumstances and benefits-associated with this modification,has directed a different approach. Specifically, the Commission has directedthe staff to approve installation of a hardened vent under the provisions of10 CFR 50.59 for licensees, who on their own Initiative, elect to incorporatethis plant improvement. The staff previously inspected the design of such asystem that was installed by Boston Edison Company at the Pilgrim NuclearPower Station. The staff found the installed system and the associatedBoston Edison Company's analysis acceptable.A copy of Boston Edison Company's description of the vent modification isenclosed for your information. For the remaining plants, the staff has beendirected to initiate plant-specific backfit analyses for each of the Mark Iplants to evaluate the efficacy of requiring the installation of hardenedwetwell vents. Where the backfit analysis supports imposition of thatrequirement, the staff is directed to issue orders for modifications toinstall a reliable hardened vent.-_,
VIfGeneric Letter 89-16 -2- September 1, 1989The staff believes that the available information provides strong incentivefor installation of a hardened vent. First, it is recognized that all affectedplants have in place emergency procedures directing the operator to vent undercertain circumstances (primarily to avoid exceeding the primary containmentpressure limit) from the wetwell airspace. Thus, incorporation of adesignated capability consistent with the objectives of the emergency procedureguidelines is seen as a logical and prudent plant improvement. Continuedreliance on pre-existing capability (non-pressure-bearing vent path) whichmay jeopardize access to vital plant areas or other equipment is an unnecessarycomplication that threatens accident management strategies. Second,implementation of reliable venting capability and procedures can reduce thelikelihood of core melt from accident sequences involving loss of long-termdecay heat removal by about a factor of 10. Reliable venting capability isalso beneficial, depending on plant design and capabilities, in reducing thelikelihood of core melt from other accident initiators, for example, stationblackout and anticipated transients without scram. As a mitigation measure,a reliable wetwell vent provides assurance of pressure relief through a pathwith significant scrubbing of fission products and can result in lowerreleases even for containment failure modes not associated with pressurization(i.e., liner meltthrough). Finally, a reliable hardened wetwell vent allowsfor consideration of coordinated accident management strategies by providingdesign capability consistent with safety objectives. For the aforementionedreasons, the staff concludes that a plant modification is highly desirableand-a prudent engineering solution of issues sur.rounding complex and uncertainphenomena. Therefore, the staff strongly encourages licensees to implementrequisite design changes, utilizing portions of existing systems to thegreatest extent practical, under the provisions of 10 CFR 50.59.As' noted previously, for facilities not electing to voluntarily incorporatedesign changes, the Commission has directed the staff to perform plant-specificbackfit analyses. In an effort to most accurately reflect plant specificity,the staff herein requests that each licensee provide cost estimates forimplementation of a hardened vent by pipe replacement, as described in SECY89-017. In addition, licensees are requested to indicate the incremental costof installing an ac independent design in comparison to a design relying onavailability of ac power. In the absence of such information; the staff willuse an estimate of $750,000. This estimate is based on modification ofprevalent existing designs to bypass the standby gas treatment system ductingand includes piping, electrical design changes, and modifications to proceduresand training.The NRC staff requests that each licensee with a Mark I plant providenotification of its plans for addressing resolution of this issue. If thelicensee elects to voluntarily proceed with plant modifications, it shouldbe so noted, along with an estimated schedule, and no further information isnecessary. Otherwise, the NRC staff requests that the above cost informationbe provided. In either event, it requests that each licensee respond within45 days of receipt of this letter.
Generic Letter 89-16-3-September 1, 1989This request is covered by Office of Management and Budget Clearance Number3150-0011, which expires December 31, 1989. The estimated average burdenhours are 100 person hours per licensee response, including searching datasources, gathering and analyzing the data, and preparing the requiredletters. These estimated average burden hours pertain only to the identifiedresponse-related matters and do not include the time for actual implementationof the requested actions. Send comments regarding this burden estimate or anyother aspect of this collection of information, including suggestions forreducing this burden, to the Record and Reports Management Branch, Divisionof Information Support Services, Office of Information Resources Management,U.S. Nuclear Regulatory Commission, Washington, D.C. 20555; and to thePaperwork Reduction Project (3150-0011), Office of Management and Budget,Washington, D.C. 20503.If you have any questions regarding this matter, please contact the NRC LeadProject Manager, Mohan Thadani, at (301) 492-1427.
Sincerely,*~ ' 5 t:Ja s 6. PartlowAss cate Director for ProjectsOffice of Nuclear Reactor Regulation
Enclosures:
1. Description of VentModification at the PilgrimNuclear Power Station2. List of Most RecentlyIssued Generic Letters
'I Enclosure 19OST0NCOPilgrim Nuclear Power StationRocky Hill RoadPlymouth, Missachusetts 02360Ralph G. BirdSenior Vice Presiaert -NuclearBECo 88-126August 18, 1988U. S. Nuclear Regulatory CommissionDocument Control DeskWashington, DC 20555License DPR-35Docket 50-293REVISED INFORMATION REGARDING PILGRIM STATIONSAFETY ENHANCEMENT PROGRAM
Dear Sir:
Enclosed is a description of a revised design for the Direct-Torus Vent System(DTVS) that was described in the "Report on Pilqrim'Station SafetyEnhancements' dated July 1, 1987 and transmitted to the NRC with Mr. Bird'sletter (BECo 87-111) to Mr. Varga dated July 8, 1987. This revision supersedesin its entirety the Section 3.2 included in the July 1, 1987 report.On March 7, 1988 Boston Edison Company (BECo) personnel met with Dr. Hurley,Mr. Russell, and Dr. Thadani and provided a tour of SEP modifications and aninformal presentation of the quantification of competing risks associated withventing the containment and conclusions drawn from these results. Thispresentation provided BECo the opportunity to respond to questions posed underItem 1 Section 3.2 -"Installation of A Direct Torus Vent System WDTVS)" in Mr.Varga's letter to Mr. Bird of August 21, 1987 "Initial Assessment of PilgrimSafety Enhancement Program". The material presented was made available to theresident Inspector and was included as Attachment II in NRC Inspection.Report#88-12, dated May 31, 1988.As you are aware from plant inspections we have installed the DTVS piping andportions of related control wiring. Currently, the DTVS is isolated from theStandby Gas Treatment System (SBGTS) by blind flanges installed in place ofValve AO-5025 and the DTVS rupture disk. This configuration was inspected byNRR in the performance of a technical review which focused on System,Mechanical Design and Structural Design issues. The review took place on March2-3, 1988 as documented in NRC Inspection Report #88-07, dated May 6, 1988 anddetermined the installation configuration to be acceptable. He now plan toremove these blind flanges and proceed with installation of Valve AO-5025 andthe DTVS rupture disk. We conclude the valve and rupture disk provideequivalent physical isolation of the DTVS piping from the SBGTS andappropriately ensure the operational integrity of the SBGTS under design basisaccident conditions. Following completion of this work, we will perform alocal leak rate test to verify that Valve AO-5025 is acceptably leak tightusing the same method previously utilized in testing the blind flange. He alsoplan to complete all remaining electrical work on the DTVS in accordance withthe revised design.PDR ADOCK 05000293 BOSTON EDISON COMPANYAugust 18, 1988U.S. Nuclear Regulatory CommissionPage 2On the basis of the revised Section 3.2, we conclude that the DTVS design asdescribed In the enclosure does not require any change to the TechnicalSpecifications and that we can proceed with installation without prior NRCapproval.Please feel free to contact me or Mr. J. E. Howard, of my staff at (617)849-8900 if you have any questions pertaining to the design details of the DTYS.G. rd
Attachment:
Section 3.2 Revision 1 NInstallation Of A Direct Torus VentSystem (DTVS)"'JEH/amm/2282cc: Mr. D. McDonald, Project ManagerDivisi'on'of Reactor Projects II.Office of Nuclear Reactor RegulationU. S. Nuclear Regulatory CommissionMail Station P1-137Washington, D.C. 20555U. S. Nuclear Regulatory CommissionRegion I475 Allendale RoadKing of Prussia, PA 19406Senior NRC Resident InspectorPilgrim Nuclear Power Station Attachment to BECo Letter 88-126Section 3.2 Revision 1 "Installation Of A Direct Torus Vent System (DTVS)Npages 14, 15, 16, 17, 18, 19, 19A, 198K 3.2 INSTALLATION OF A DIRECT TORUS VENT SYSTEM COTVS)3.2.1 Obiective of Design ChangeThis design change provides the ability for directventing of the torus' to the main 'stack'. Cbntainmentventing is one core damage prevention strategy utilizedin the SWHROwners Group Emergency Procedure Guidelines(EPGs) as previously approved by the NRC and is requiredin plant-specific Emergency Operating Procedures (EOPs).The torus vent line connecting the torus to the mainstack will provide an alternate vent path forimplementing EOP requirements and represents asignificant improvement relative to existing plant ventcapability. For 56 psi saturated steam conditions in thetorus, apporoximately 11 decay heat can be vented.3.2.2 Design Change DescriptionThis design change (Figure 3.2-1) provides a direct ventpath from the torus to the main stack bypassing theStandby Gas Treatment System (SBGTS). The bypass is an8" line whose upstream end is connected to the pipebetween primary containment isolation valves AO-5042 A &B. The downstream end of the bypass is connected to the20" main stack line downstream of SBGTS valves AON-108and AON-112. An 8" butterfly valve (A0-5025), which canbe remotely operated from the main control room, is addeddownstream of 8" valve AO-5042B. This valve acts as theprimary containment outboard isolation valve for thedirect torus vent line and will conform to NRCrequirements for sealed closed isolation valves asdefined in NUREG 0800 SRP 6.2.4. The new pipe is ASMEIII Class 2 up to and inclusive of valve AO-5025. Testconnections are provided upstream and downstream ofAO-5025.The design change replaces the existing AC solenoid valvefor AO-5042B with a DC solenoid valve (powered fromessential 125 volt DC), to ensure operability withoutdependence on AC power. The new isolation valve,AO-5025, is also provided with a DC solenoid powered fromthe redundant 125 volt DC source. Both of these valvesare normally closed and fail closed on loss of electricaland pneumatic power. One inch nitrogen lines are addedto provide nitrogen to valves AO-5042B and AO-5025. Newvalve AO-5025 will be controlled by a remote manualkey-locked control switch. During normal operation,power to the AO-5025 DC solenoid will also be disabled byremoval of fuses in the wiring to the solenoid valve.This satisfies NUREG 0800 SRP 6.2.4, ContainmentIsolation System acceptance criteria for a sealed closedbarrier. An additional fuse will be installed and remainin place to power valve status indication for AO-5025 inthe main control room.-14-Re (7/25/88)
NUREG 0800, SRP 6.2.4, Item 1I.6.F allows the use ofsealed closed barriers in place of automatic isolationvalves. Sealed closed barriers include blind flanges andsealed closed isolation valves which may be closedremote-manual valves. SRP 6.2.4 calls for administrativecontrol to assure that sealed closed isolation valvescannot be inadvertently opened. This includes mechanicaldevices to seal or lock the valve closed, or to preventpower from being supplied to the valve operator.Consistent with SRP 6.2.4, valve AO-5025 will be a sealedclosed remote manual valve under administrative controlto assure that it cannot be inadvertently opened.Administrative control will be maintained by a key-lockedremote manual control switch and a fuse removed toprevent power from being supplied to the valve operator.In accordance with NUREG 0737, Item II.E.4.2.7 Position6, AO-5025 will be sealed closed and verified as such atleast every 31 days.A 20"S pipe will replace the existing 20N diameter ductbetween SBGTS valves AON-108, AON-112 and the existing20" pipe to the main stack. The existing 20" diameterduct downstream of AO-5042A is shortened to allow fitupof the new vent line branch connection.A rupture disk will be included in the 8S piping*downstream of valve AO-5025. The rupture disk willprovide a second leakage barrier. The rupture disk isdesigned to open below containment design pressure, butwill be intact up to pressures equal to or greater thanthose which cause an automatic containment isolationduring any accident conditions.The two Primary Containment Isolation Valves (PCIMs)AO-50428 and AO-5025 are placed in series with therupture disk. No single operator error in valveoperation can activate the DTVS. The rupture disk has arupture pressure above the automatic containment highpressure trip point. Thus, the inboard PCIV (AO-5042B)will receive an automatic isolation prior to diskrupture. The inboard PCIV (AO-5042B) requires physicalelectrical jumper installation to open at primarycontainment pressure above the automatic high pressuretrip point.Valve AO-5025 will be closed whenever primary containmentintegrity is required and'DC power to its solenoidcontrol valve will be disconnected. Indication of valveposition will be provided in the main control room evenwith the valve power removed. Use of the direct torusvent will be in accordance with approved EPG requirementsand controlled by EOPs in the same manner as otherexisting containment vent paths. Prior to opening thevent valves the SBGT system will be shutdown and valvesAON-108 and AON-112 (the outlet of SBGT) placed in a-,,closed position. V-15- Re (7/25/88):
New 8" vent pipe (8"-HBS-44), including valve AO-5025 issafety related. Vent piping downstream of AO-5025,including SBGTS discharge piping to main stack, is alsosafety related. All safety related piping will besupported as Class I. Nitrogen piping is non-safetyrelated and will be supported as Class II/I.The Interpretation of the Class II/I designation throughthis report is given below:All Class II items which have the potential to degradethe integrity of a Class I item are analyzed. SuchClass II items do not require dependable mechanical orelectrical functionality during SSE. only that all of thefollowing conditions prevail:1. The Class II items create no missiles which impactunprotected Class I Items safety functions.2. The Class II item does not deform in a way whichwould degrade a Class I item.3. If the Class II item fails, then the Class I item isprotected against the full impact of all missilesgenerated by the assumed failure of Class II items.All electrical portions of this design are safety relatedexcept for the indicating lights on the MIMIC panel C904,the tie-ins to the annunciator, and interface with theplant computer.3.2.3 Design Change Evaluation3.2.3.1 Systems/Components AffectedContainment Atmospheric Control System (CACS)The torus purge exhaust line inboard isolationvalve AO-50428 and the associated 80 pipe arethe components of the CACS affected by thedesign modification. With incorporation of thesubject modification, the CACS will depend onboth essential AC (for valve AO-5042A) andessential DC (far AO-5042B) to perform itspurging function.The new 8" torus vent line will be connected toexisting 8" CACS piping between valves AO-50429and AO-5042A.-16-Re (7/25/88)
Standby Gas Treatment System (SBGTS)The SBGTS fan outlet valves (AON-108 andAON-112), ductwork from these valves to the 20"line leading to the main stack, and the 20Kline leading to the main stack are thecomponents of this system affected by theproposed change.Valve AON-108 is normally closed, fail-open.Valve AON-112 is normally closed, fail-closed,and these valves are provided with essential DCpower and local safety related air supplies.Primary Containment Isolation System (PCIS)Valve AO-5042B is affected by the change fromAC to DC power for the solenoid and byreplacement of the existing air supply withnitrogen. The addition of containment outboardisolation valve (AO-5025) will not affect thePCIS.Primary Containment System (PCS)Valve AO-5025 acts as the primary containmentoutboard isolation valve for the direct torusvent line and will conform to NRC requirementsfor sealed closed isolation valves as definedin NUREG 0800 SRP 6.2.4.3.2.3.2 Safety Functions of Affected Systems/ComponentsContainment Atmospheric Control SystemThis system has the safety function of reducingthe possibility of an energy release within theprimary containment from a Hydrogen-Oxygenreaction following a postulated LOCA combinedwith degraded Core Standby Cooling System.Standby Gas Treatment SystemThis system filters exhaust air from thereactor building and discharges the processedair to the main stack. The system filtersparticulates and iodines from the exhauststream in order to reduce the level of airbornecontamination released to the environs via themain stack. The SBGTS can also filter exhaustair from the drywell and the suppression pool._1 7_-17- Re (7125188)
4. .,Primary ntainment Isolation SystemThis system provides timely protection againstthe onset and consequences of design basisaccidents involving the gross release ofradioactive materials from the primarycontainment by initiating automatic isolationof appropriate pipelines which penetrate theprimary containment whenever monitoredvariables exceed pre-selected operational111its.Primary Containment SystemThe primary containment system, in conjunctionwith other safeguard features, limits therelease of fission products In the event of apostulated design basis accident so thatoffsite doses do not exceed the guidelinevalues of 10 CFR 100.3.2.3.3 Potential Effects on Safety FunctionsContainment Atmospheric Control SystemStandbyGas Treatment System. Primary ContainmentIsolation System and Primary Containment SystemThe improvements change the AO-50428 solenoidcontrol from AC to DC enabling it to open (fromits normally closed position) with nodependence on AC power availability. Theexisting air supply to AO-5042B is beingreplaced by nitrogen.Ductwork at the outlet of the SBGTS is replacedwith pipe and the new vent line is connected tothe 200 line at the outlet of the SBGTS.Addition of a new 80 vent line with containmentisolation valve AO-5025 offthe existing torusvent line could introduce a flow path underdesign basis conditions that could vent thecontainment directly to the stack bypassing theSBGTS.3.2.3.4 Analysis of Effects on Safety FunctionsAn analysis of the effects on the safetyfunctions of CACS, SBGTS, PCIS and PCS for theinstallation of the direct torus vent isdescribed as follows:The change from AC to DC control and thereplacements of air with nitrogen on AO-5042Bdoes not adversely affect the ability to openAO-50428 when the containment is being purged,or to isolate under accident conditions.-18-Re (7/25/88)
The modifications to the ductwork and 200 lineleading to the main stack do not affect thedesign basis safety function of any of thesafety related systems.During normal plant operations, the CACS andthe SBGTS do not use the torus 200 purge andvent line to perform their safety functions.The containment isolation valves are in theirnormally closed position, thus maintainingprimary containment boundary integrity.There are no adverse affects on the primarycontainment system by the addition of theDTVS. Valve AO-5025 will conform to NRCcriteria for sealed closed isolation valves asdefined in NUREG 0800 SRP 6.2.4 and will notaffect design basis accidents. Use of the DTVSwill be in accordance with the containmentventing provisions of EPGs as approved by theNRC and controlled by EOPs in the same manneras other existing containment vent paths. Theeffects on the torus of the new 80 piping andAO-5025 have been evaluated for Mark I programloadings, using ASME BPVC Section IIIcriteria. The remaining piping including therupture disk was evaluated using ANSI B31.1requirements.During plant startup and shutdown(non-emergency condition) when the purge andvent line is in use, valve AO-5025 remainsclosed. In addition, the rupture diskdownstream Qf valve AO-5025 will provide asecond positive means of preventing leakage andprevent direct release up to the stack duringcontainment purge and vent at plant startup orshutdown.During containment high pressure conditions,the torus main exhaust line is automaticallyisolated by the PCIS. There is no change tothe existing primary containment isolationsystem function for AO-5042A or AO-5042B. Thesealed closed position of valve AO-5025 and theadditional assurance added by the rupture diskdownstream will prevent any inadvertentdischarge up the stack for all design basisaccident conditions.3.2.3.5 Design Change Evaluation Summary Conclusions-Installation of the DTVS does not adverselyaffect the safety functions of the CACS, SBGTS,PCIS or the integrity of primary containment orany other safety related systems.-19-Re (7/25/88)
Use of the DTVS will be In accordance with thecontainment venting provisions of EPGs asapproved by the NRC and controlled by EOPs inthe same manner as other existing containmentvent paths. The DTVS provides an improvedcontainment venting capability for decay heatremoval which reduces potential onsite andoffsete impacts relative to the existingcontainment venting capability.-19A-Re (7/25/88)
U,-DIRECT 7ORUS VEwNT SYSTEMFIGURE 32-1REMOTEK"NUALSW srIIII(RUPTURE/(DISKC.4 1M ./OaY-eoog.( .FOM CTPIPE --~ EXISTING9AE97ya NEW PIPERPF.V X. IL 2/ i 4. iEnclosure 2LIST OF RECENTLY ISSUED GENERIC LETTERSDate ofGenericLetter No. SubJect Issuance89-16 INSTALLATION OF A HARDENED 09/01/89WETWELL VENT (GENERICLETTER 89-16)88-20 GENERIC LETTER 88-20 08/29/89SUPPLEMENT 1 SUPPLEMENT NO. 1(INITIATION OF THE INDIVIDUALPLANT EXAMINATION FOR SEVEREVULNERA8ILITIES 10 CFR 50.54(f))89-15 EMERGENCY RESPONSE DATA 08/21/89SYSTEM GENERIC LETTER NO.89-15CORRECT ACCESSION NUM8ER IS 890822042389-07 SUPPLEMENT 1 TO GENERIC 08/21/89LETTER 89-07 'POWER REACTORSAFEGUARDS CONTINGENCYPLANNING FOR SURFACEVEHICLE BOMBS-89-14 LINE-ITEMS TECHNICAL SPECIFI- 08/21/89CATION IMPROVEMENT -REMOVALOF 3.25 LIMIT ON EXTENDINGSURVEILLANCE INTERVALS(GENERIC LETTER 89-14)89-13 GENERIC LETTER 89-13 7/18/89SERVICE WATER SYSTEMSPROBLEMS AFFECTINGSAFETY-RELATED EQUIPMENT89-12 GENERIC LETTER 89-12: 7/6/89OPERATOR LICENSINGEXAMINATIONSIssued ToALL GE PLANTSALL LICENSEESHOLDING OPERATINGLICENSES ANDCONSTRUCTIONPERMITS FORNUCLEAR POWERREACTOR FACILITIESALL HOLDERS OFOPERATING LICENSESOR CONSTRUCTIONPERMITS FOR NUCLEARPOWER PLANTSALL LICENSEES OFOPERATING PLANTS,APPLICANTS FOROPERATING LICENSES,AND HOLDERS OFCONSTRUCTION PERMITSALL LICENSEES OFOPERATING PLANTS,APPLICANTS FOROPERATING LICENSES,AND HOLDERS OFCONSTRUCTION PERMITSLICEMIEES TO ALLPOWEWtREACTORSBWRS, PWRS, ANDVENDORS IN ADDITIONTO GENERAL CODESAPPLICABLE TOGENERIC LETTERSLICENSEES TO ALLPOWER REACTORSBYRS. PWRS, ANDVENDORS IN ADDITIONTO GENERAL CODESAPPLICABLE TOGENERIC LETTERSUNITED STATESNUCLEAR REGULATORY COMMISSIONWASHINGTON, D.C. 20556OFFICIAL BUSINESSPENALTY FOR PRIVATE USE, $300FIRST CLASS MAILPOSTAGE & FEES PAIDUSNRCPERMIT No. 047
_ -e 5cc w/enclosure:J. TaylorH. Thompsonivision Directors, NRRA sociate Directors, NRRPr ject Directors, NRRReg onal AdministratorsJ. C nran, CRGRC. Be lingerS. Tre4N'd'SPLB:D SP T SPLB:DEST SAD:DEST NRR:OGCBCLi;cfM 1 JKudrick CMcCracken AThadani CBerlinger8/of/89 8cv\/89 8/Z 189 8/ /89 8/ /89NRR:DOEA NRR:PD1-2 NRR:DRP RR:ADT NRR:ADPCRossi MThadani SVarga F!iraglia JPartlow8/ /89 8/ /89 8/ /89 8/\ /89 8/ /89