ML071840077

(PA-LR) Pages 2-38 Info

ML071840077
Person / Time
Site:	Vermont Yankee
Issue date:	06/18/2007
From:	Hamer M Entergy Corp
To:	Rowley J NRC/NRR/ADRO/DLR
References
TAC MD2297
Download: ML071840077 (25)

Text

Pg 2-38 info Page I of I Jonathan Rowley - Pg 2-38 info From: "Hamer, Mike" <fnhamer@entergy.com>

To: "Jonathan Rowley" <JGR@nrc.gov>

Date: 06/18/2007 12:02 PM

Subject:

Pg 2-38 info The PNP SER states:

"The staff examined the applicant's environmental report, Appendix E, Attachment E.I, "Evaluation of Probabilistic Safety Analysis Model," to verify that there is no risk significance system in the list. None of the 14 systems is a dominant contributor to the risk reduction worth rankings to core damage frequency nor are these systems involved in the dominant initiating events

<

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Subject:

Pg 2-38 info Creation Date 06/18/2007 12:01:38 PM From: "Hamer, Mike" <mhamer(ientergy.com>

Created By: mhamer(aentergy.com Recipients nrc.gov TWGWPO03.HQGWDOOI JGR (Jonathan Rowley)

Post Office Route TWGWPO03.HQGWDOOI nrc.gov Files Size Date & Time MESSAGE 482 06/18/2007 12:01:38 PM TEXT.htm 1516 Table RAI. 1-3.doc 60928 ER Table E. 1-3.doc 698880 Revised Table E. 1-3.doc 770560 Mime.822 2099464 Options Expiration Date: None Priority: Standard ReplyRequested: No Return Notification: None Concealed

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.JUI-.LIldII r*,JWI~y -. I able r'd.-I.I-.Coc I J~~I1 Table RAI.1-3 Summary of Major PSA Model Versions Model CDF' LERF RPE transients & LOCAs) 4.3 E-06 9.4 E-07 VY1 18 (transients & LOCAs) 4.9 E-06 n/a IPEEE (internal floods) 9.0 E-06 n/a VYQORO 1.78E-05 9.33E-07 VY02RO 4.28E-06 1.05E-06 VY02R1 4.28E-06 1.12E-06 VY02R2 4.62E-06 n/a VY02R3 4.89E-06 n/a VYO2R4 7.81 E-06 n/a VY.2R5 7.81.E-06 2.29E-6 VY02R6 7.77E-06 2.29E-06 VY02R7 7.63E-06 2.23E-06 VYO2R8 8.73E-06 2.61 E-06 VY04RO 4.91 E-06 1.50E-06 VY04R1 5.03E-06 1.56E-06 VY05RO 7.98E-06 2.50 E-6 IWith the exception of the original IPE, IPEEE, and version VY118 CDF and LERF values, subsequent VYNPS model version updated CDF and LERF values include the combine contributions from transients, LOCAs and Internal floods Initiators.

§Jonathn- RoWley-_ _ERTable-EE.1-3.doc' Page 1t Vermont Yankee Nuclear Power Station Applicant's Environmental Report Operating License Renewal Stage Table E.1-3 Correlation of Level 1 Risk Significant Terms to Evaluated SAMAs Risk Significant Terms RRW Disposition HPCI 1.4966 This term represents random failure of the HPCI system. Phase I SAMAs to imorove availability and reliability of the HPCI system that have already been implemented include raising backpressure trip setoints and proceduralizing intermittent operation. Additional improvements were evaluated in Phase II SAMAs 049, 050, 051, 052, 053, and 054.

RCIC 1.4223 This term represents random failures of the RCIC system. Phase I SAMAs to improve availability and reliability of the RCIC system that have already been installed include raising backDressure tp setpoints and proceduralizing intermittent operation. Additional improvements were evaluated in Phase II SAMAs 049, 050, 051, 052, 053, and 054.

ECCS Low Pressure Interlock 1,3472 This term represents random failures of reactor low-pressure transmitters during transients with stuck open SRVs or LOCAs in which random failures prevent all low-pressure injection valves from opening. Phase II SAMAs 065 and 066 to reduce the risk due to failure of the ECCS low-pressure interlock were evaluated.

Djepressurization (SRVs and ADS 1.2724 This term represents random failures of the SRVs to open for depressurization during Logic) transients and small LOCAs. Phase I SAMAs to enhance reliability of the SRVs that have already been implemented include adopting symptom based EOPs and SAGs, modifying ADS logic, and upgrading SRV pneumatc components. Additional improvements were evaluated in Phase 11SAMAs 059 and 060.

Loss of Feedwater - initiating event 1.1796 This term represents the initiating event for loss of feedwater. Modifications to significantly reduce or eliminate the potential for loss of feedwater, such as installing a digital feedwater control system, providing a backup water supply and adding a third feedwater pump, have already been implemented. Many of the Phase II SAMAs (e.g., 035, 051, 052. 053. and 054) explored potential benefits for mitigation of this event.

E.1-4

Jonathan Rowley - ER Table E.1-3.doc Page2 Vermont Yankee Nuclear Power Station Applicants Environmental Report Operating License Renewal Stage Table E.1-3 Correlation of Level 1 Risk Significant Terms to Evaluated SAMAs (Continued)

Risk Significant Terms RRW Disposition Operator Action: 1.1110 This term represents operator failure to manually open the SRVs for depressurization during Operator fails to open SRVs for transients and small LOCAs. Phase I SAMAs including improvements to plant procedures, and vessel depressurization during installation of instrumentation to enhance the likelihood of success of operator action in transients and small LOCA response to accident conditions, have already been implemented No additional Phase 11 SAMAs were recommended for this subject.

Loss of Offsite Power - initiating 1,0951- This term represents the loss of offsite Power initiating event. Industry efforts over the last event PC twenty years have led to a significant reduction in plant scrams from all causes. Improvements PC - Plant Centered 1.0605- related to enhancing offsite oower availability or reliability and coping with plant SBO events GR - Grid Related GR were already implemented and evaluated during preliminary SAMA screening- Phase II SAMAs 028. 029, 030, 031, 033 and 036 for enhancing AC or DC system reliability or to cope with loss of offsite power and SBO events were evaluated.

Torus Vent via TVS-86 and 1,0948 This term represents random failures of components in the containment vent path. A hardened Rupture Disk pipe vent path was implemented as a result of the NRC Containment Performance Program to provide a redundant means for containment heat removal capability. Several Phase I SAMAs regarding the drywell spray system were already installed to provide containment decay heat removal capability by plant design. Therefore, no Phase It SAMAs were proposed to reduce random failure of containment vent path components. However. Phase II SAMA 063 to control containment venting within a narrow pressure band to prevent rapid depressurzation during venting was evaluated.

Loss of 4.16KV Bus 3 - initiating 1.0869(IE) This term represents loss of 4.16KV bus 3. Phase I SAMAs to improve 4.16KV bus crosstie event capability and procedures to repair or replace failed 4.16KV breakers have already been Implemented. Phase II SAMAs 028, 029, 030, 031, 033 and 036 for enhancing AC or DC system reliability or to cope with loss of offsite power and SBO events were evaluated.

E.l-5

Page 3 I I

Jonathan Rowley- ER Table E.1--3.doc .............................

Vermont Ya*ree Nuclear Power Station Applicant's Environmental Report Operating License Renewal Stage Table E.1-3 Correlation of Level 1 Risk Significant Terms to Evaluated SAMAs (Continued)

Risk Significant Terms RRW Disposition Emergency Diesel Generators 1.0810 This term represents random failures of the emergency diesel generators, leading to an 8B0 (A & B) event. Phase I SAMAs to improve reliabilityof the emergency diesel generators by creating a crosstie of EDG fuel oil supplies and a backup source for diesel cooling have already been installed. In addition, Phase 11SAMAs 002. 003 and 032 to improve reliability of the EDGs were evaluated.

Loss of 4.t6KV Bus 4 - initiating 1.0756 This term represents loss of 4.16KV bus 4. Phase I SAMAs to improve 4.16KV bus crosstle event capability and procedures to repair or replace failed 4.16KV breakers have already been installed. Phase II SAMAs 028, 029, 030, 031, 033 and 036 for enhancing AC or DC system reliability or to cope with loss of offsite power and SBO events were evaluated.

Operator Action: 1.0685 This term represents operator failure to initiate HPCI/RCIC to perform the core cooling function Operator fails to initate HPCIRCIC dunng transients, medium LOCAs, and small LOCAs when automatic initiation fails. Phase I during transients, medium and SAMAs Including improvements to plant procedures. and installation of instrumentation to small LOCAs enhance the likelihood of success of operator action in response to accident conditions, have already been implemented. No additional Phase II SAM.As were recommended for this subject.

Operator Action 1.0650 This term represents operator failure to align the John Deere diesel generator to provide Operator fails to align firewater electric power to 480VAC bus 9 during a loss of offsite power event. With bus 9 energized and system and John Deere Diesel for supplying MCC8B and 9B, battery charging is maintained as well as power to RHR valves alternate injection necessary for aligning the diesel fire pump for alternate RPV vessel injection. Phase I SAMAs including Improvements to plant procedures, and installation of instrumentation to enhance the likelihood of success of operator action in response to accident conditions, have already been implemented. No additional Phase II SAMAs were recommended for this subject.

E.1-6

I. *..

I Jonathan Howley - ER Table E. 1-3.doc Page 4, I Vermont Yankee Nuclear Power Station Applicants Environmental Report Operating License Renewal Stage Table E.1-3 Correlation of Level 1 Risk Significant Terms to Evaluated SAMAs (Continued)

Risk Significant Terms RRW Disposition Containment N 2 1.0553 This Termrepresents random failure of the containment nitrogen system for SRV operation during loss of ofisite power. A Phase I SAMA, adding high-pressure nitrogen bottles as a backup to the normal nitrogen suply. has already been installed to improve reliability of the containment nitrogen system. Since failure of the SRVs has a larger risk reduction worth than failure of this supoort system, the beneft derived from Phase I SAMA 060, 'Improve SRV design," Is greater than the benefit oossible from improving the nitrogen supply system. Also, the cost of adding another nitrogen suopty is judged comparable to the cost of modifying the SRVs. Therefore, no Phase II S.I.AAs were evaluated to further imorove reliability of nitrogen supoly to the SRVs.

Diesel Fire Pumo and JohnDeere 1.0584 . This term represents random failure of diesel fire pump P40-1A and John Deere diesel Diesel for Alternate Injection generator during the alignment of John Deere diesel generator to provide altemate RPV vessel injection during a loss of oftsite power event. Phase I SAMAs to use the fire protection system as a backup source for containment spray and reactor vessel injection during loss of offsile power have already been installed to provide redundant capability for RPV injection and heat removal. Phase !1SAMA 064 to provide a crosstie for fire protection from RHRSW system to RHR loop B to further improve injection capability was evaluated.

Inadvertent Opening of Relief 1.0571 This term represents the initiating event of inadvertent opening of a relief valve. Improvement Valve--initiating event of the SRV design and SRV reseat reliability, to reduce the probability and consequences of this initiating event, were evaluated in Phase II SAMAs 055 and 060.

Loss of Bus DC-1 and associated 1.0541(IE) These terms represent the initiating event of a complete loss of the 125VDC bus DC-i and battery---ilitiating event 1.0264 random failures of battery A-I. Phase I SAMAs ro imorove alternate battery charging capability, replace existing batteries with more reliable ones, and DC bus crosstie capability have already been installed. Phase II SAMAs 028, 029, 030, and 033 for enhancing DC system availability and reliability were evaluated.

E.1-7

JonathaRoley - ER Table E.1-3.doc 9 Pýage Vermont Yankee Nuclea Power Station Applicants Environmental Report Operating License Renewal Stage Table E.1-3 Correlation of Level 1 Risk Significant Terms to Evaluated SAMAs (Continued)

Risk Significant Terms . RRW Disposition Loss of Bus DC-2 and associated 1.0517(IEj These terms represent the initiating event of a complete loss of 125V0C bus DC-2 and battery - initiating event 1.0316 random failures of battery B-1. Phase I SAMAs to improve alternate battery charging capability, replace existing batteries with more reliable ones and DC bus crosstie capability have already been installed. Phase 11SAMAs 028, 029, 030. and 033 for enhancing DC system availability and reliability were evaluated.

Torus Cooling Mode of RHR & 1.0515 This temn represents random failure of the torus cooling mode of the RHR and RHRSW RHRSW systems. Containment spray mode of RHR and fire protection system crosstie has already been implemented to provide redundant containment heat removal capability. In addition, Phase II SA-MAs 004, 010 and 017 to improve the reliability of containment decay heat removal were evaluated.

Operator Action' 1.0408 This term represents operator failure to manually open the SRVs to depressurize during a Operator fails to open SRVs for medium LOCA. Phase I SAMAs including improvements to plant procedures, and installation vessel devressurzation during of instrumentation to enhance the likelihood of success of operator action in response to medium LOCA accident conditions, have already been implemented. No additional Phase II SAMAs were recommended for this subject Loss of Service 'WNater- initiating .1.0102 These terms reoresent random passive failures of the service water system and the initiating event event of a complete loss of the service water system. Enhancement of the service water system was evaluated in Phase i1SAMA 001 Internal Flooding Initiator, SW pipe 1.0397 This term represents the initiating event of SW pipe break in torus room, at El. 213' of the break in torus room, at El, 213' of reactor building. A Phase I SAMA. enhancement of 'Loss of Service Water' procedure to the reactor building contain a mitigation strategy for each'break location, has already been implemented. In addition, Phase I1SAMA 047 to reduce the COF contribution of internal flooding was evaluated.

IJowey - ER Table E.1-3.doc - _ Page6I Vermont Yankee Nuclear Power Station Applicant's Environmental Report Operating License Renewal Stage Table E.1-3 Correlation of Level 1 Risk Significant Terms to Evaluated SAMAs (Continued)

Risk Significant Terms RRW Disposition Ooerator Action: 1.0367 This term represents operator failure to recognize the need to vent the torus for pressure Operator fails to recognize the reduction during loss of containment heat removal accident sequences. Phase II SAMA 063 need to vent the torus for pressure to control containment venting within a narrow pressure band to prevent rapid containment reduction deoressurization during venting was evaluated-Internal Flooding Initiator, SW pipe 1.0357 This term represents the initiating event of SW pipe break inNE ECCS corner room of the break in NE ECCS corner room of reactor building. A Phase I SAMA to increase bernm height to prevent flooding of the ECCS the reactor building corner room has already been installed. In addition, Phase II SAMA 047 to reduce the COF contribution of internal flooding was evaluated Internal Flooding Initiator, SW tipe 1.0343 This ternmrepresents the initiating event of SW pipe break in SE ECCS comer room of the break in SE ECCS corner room of reactor building. A Phase I SAMA modifying and sealing the hatch liftpoints and hatch edges the reactor building has already been installed to ensure hatches are watertight. In addition. Phase It SAMA 047 to reduce the CDF contribution of internal flooding was evaluated.

Internal Flooding Initiator. SW oipe 1.0324 This term represents the initiating event of SW pipe break at El. 303' of the reactor building. A break at El. 303' of the reactor Phase I SAMA, adding chase berms at elevation 303', has already been installed. In addition, building Phase II SAMA 047 to reduce the CDF contribution of internal flooding was evaluated.

Bus 2 (supplied by SU XFMR) - 1.0318 This term represents the initiating event of a complete loss of offsite power from the 345 KV 4..16KV switchyard and 115 KV line. Phase I SAMAs to improve 4.16KV bus crosstie capability, procedures to repairor replace failed 4.16KV breakers and provide connection to an alternate source of offsite power have already been installed. Phase 11SANIAs 028, 029, 030, 031. 033 and 036 for enhancing AC or DC system reliability or to cope with loss of offsile power and SBO events were evaluated.

E. 1-9

Jonathan Rowley - ER Table E.1-3.doc Page 7 Vermont Yankee Nuclear Power Station Applicant's Environmental Revort Operating License Renewal Stage Table E.1-3 Correlation of Level 1 Risk Significant Terms to Evaluated SAMAs (Continued)

Risk Significant Terms RRW Disposition RPS 1.0316 This term represents random failure of the reactor protection system. Several Phase I SAMAs to minimize the risks associated with ATWS scenarios have already been installed. No Phase IISAMAs were evaluated to further improve reliability of RPS. However, Phase IISAMAs 057 and 058 to enhance thereliability of the standby liquid control system and improve ATrwS capability to mitigate the consequences of this event were evaluated.

Transient with PCS available - 1.0287 This term represents the initiating event of a transient with PCS available. Industry efforts over initiating event the last twenty years have led to a significant reduction of plant scrams from all causes. Phase IISAMA 046 to improve MSIV design and mitigate the consequences of this event was evaluated.

Operator Action' 1.0282 This term represents operator failure to align condensate transfer pump to inject via LPCI or Operator fails to align a core spray lines for alternate injection. Phase I SAMAs including improvements to plant condensate transfer pump to inject procedures, and installation of instrumentation to enhance the likelihood of success of via LPCI or core spray lines for operator action inresponse to accident conditions, have already been implemented. No altemate injection additional Phase It SAMAs were recommended for this subject.

Operator Action: 1.0257 This term represents operator failure to align water from the west cooling tower deep basin to Operator fails to initiate alternate the suction of the RHIRSW pumps to cool a number of loads normally cooled by the service cooling mode from the cooling water system. Phase I SAMAs including improvements to plant procedures, and installation tower deep basin of instrumentation to enhance the likelihood of success of operator action in response to accident conditions, have already been implemented. No additional Phase ItSAMAs were recommended for this subject.

E.1-10

IJonathan Rowley - ER Table E.1-3.doc PageKi Vermont Yankee Nuclear Power Station Applicant's Environmental Report Operating License Renewal Stage Table E.1-3 Correlation of Level 1 Risk Significant Terms to Evaluated SAMAs (Continued)

Risk Significant Terms RRW Disposition FeedwateriCondensate 1.0237 This term represents random failure of the feedwater and condensate injection path. Phase I SAMAs creating connections of existing or alternate water sources to feedwater and condensate, and installing motor driven feed water pumps, have already been installed to increase the availability of injection subsequent to MSIV closure. Many of the Phase II SAMAs (e.g 050, 051, 052, 053, and 054) explored potential benefits of enhancing the rellability of high pressure injection systems.

Internal Flooding Initiator, SW oipe 1.0218 This term represents the initiating event of SW pipe break in NE EGCS corner room of the break (north) affecting MCCs and reactor building. A Phase I SAMA, enhancement of 'Loss of Service Water* procedure to ECCS in NE corner room of the contain a mitigation strategy for each break location, has already been implemented. In reactor building addition. Phase II SAMA 047 to reduce the COF contribution of internal flooding was evaluated.

Bus 1 (supplied by SU XFMR) - 1.0200 This term represents the initiating event of a complete loss of offsite power from the 345 KV 4.16KV switchyard and 115 KV line. Phase I SAMAs to improve 4.16KV bus crosstie capability, procedures to repair or replace failed 4.16KV breakers and provide connection to an alternate source of offsite power have already been installed. Phase II SAMAs 028. 029, 030, 031, 033 and 036 for enhancing AC or DC system reliability or to cope with loss of offsite power and SBO events were evaluated.

Vernon Tie 1.0153 This term represents random failure of Vlemon tie line circuit breakers to close and operator failure to close two breakers from the control room. Phase I SAMAs to orovide an alternate source of offsite power. proceduralize steps in recovery or offsite power after 310, and protect control cable of Vernon iebreakers have already been installed. No Phase It SAMAs were evaluated to further improve reliability of the Vernon tie. However, Phase It SAMAs 028. 029, 030. 031. 033 and 036 for enhancing AG or DC system availability or reliability to cope with the loss of oflsite power and SBO events were evaluated.

E. t11

I[Jonathan Rowley - ER Table E.1-3.doc Page 9.1 I

Tý!RqRd Vermont Yankee Nucleor Power Station Applicane's Environmental Report Operating License Renewal Stage Table E.1-3 Correlation of Level 1 Risk Significant Terms to Evaluated SAMAs (Continued)

Risk Significant Terms RRW Disposition Internal Flooding Initiator, fire 1.0177 This term represents the initiating event of fire protection pipe break in torus room, at El. 232' protection pipe break in upper of the reactor building- A Phase I SAMA, to provide a relief path to relieve water accumulation RCIC room at El. 232' in the upper RCIC to lower RCIC area before floor failure, has already been implemented. In addition. Phase II SAMA 047 to reduce the COF contribution of internal flooding was evaluated.

ATWS with MSIV Closed -initiating 1.0155 This term represents the ATWS initiating event. Several Phase I SAMAs to create a boron event injection path through CRD, increase boron concentration, and provide RPT. ARI, and FW trip to minimize the risks associated with ATWS scenarios have already been installed. In addition. Phase II SAMAs 057 and 058 to enhance reliability of the standby liquid control system and improve ATWS capability to mitigate the consequences of this event were evaluated.

Internal flooding Initiator, SW pipe 1.0144 This term represents the initiating event of SW pipe break at El. 280' of the reactor building. A break in affecting instrument Phase I SAMA, enhancement of"Loss of Service Water" procedure to contain a mitigation panels and 480v MCC, at El. 280' strategy for each break location, has already been implemented. Inaddition, Phase II SAMA of the reactor buitlding 047 to reduce the CDF contribution of internal flooding was evaluated Alterate Cooling 1 0143 This term represents random failure of alternate cooling from the west cooling tower deep basin to the suction of the RHRSW pumps. Phase II SAMA 064 to improve alternate cooling capability was evaluated.

Stuck Open SRVs - initiating event 1.0139 This term represents the initiating event of stuck open SRVs. Improvement of SRV reseat reliability and SRV design were evaluated in Phase II SAMAs 055 and 060.

Ooerator Action: 1.0133 This termirepresents operator failure to start TBCCW pump locally from the motor control Operator fails to start a TBCCW panel and establish cooling to BOP components for RPV makeup and heat removal- Phase I pUmp SAMAs including improvements to plant procedures, and installation of instrumentation to enhance the likelihood of success of operator action in response to accident conditions, have already been implemented No additional Phase It SAMAs were recommended for this subject E.1-12

Jonatan Ro ley kElable E.1-3'.doc PageJ10 Vermont Yankee Nuclear Power Station Applicant's Environmental Report Operating License Renewal Stage Table E.1-3 Correlation of Level 1 Risk Significant Terms to Evaluated SAMAs (Continued)

Risk Significant Terms RRW Disposition Intemal Flooding Initiator, 1.0130 This term represents the initiating event of circulating water pipe break in the turbine building, circulating water pipe break in Phase I SAMAs to improve inspection of expansion joints on the main condenser and to turbine building change procedures to reduce the probability of a circulating water piping break have already been implemented. No Phase It SAMA was evaluated to further reduce this initiator.

However, Phase It SAMA 047 to reduce the CDF contribution of internal flooding was evaluated.

Operator Action: 1.0130 This teim represents operator failure to Initiate SLC dudng an ATWS without main condenser.

Operator fails to initiate SLC during Phase I SAMAs including improvements to plant procedures, and installation of an ATS without main condenser instrumentation to enhance the likelihood of success of operator action in response to accident conditions, have already been implemented. No additional Phase I SAMAs were recommended for this subject Internal Flooding Initiator. SW pipe 1.0119 This term represents the Initiating event of SW pipe break In the intake structure. Phase I1 break in intake structure SAMA 047 to reduce the CDF contribution of internal flooding was evaluated.

Loss of PCS - initiating event 1.0111 This term represents the initiating event of a loss of PCS. Industry efforts over the last twenty years have led to a significant reduction of plant scrams front all causes. Phase It SAMA 046 to improve MSIV design and mitigate the consequences of this event was evaluated.

Operator Action: 1.0079 This term represents operator failure to align feedwater and condensate injection to perform Operator fails to initiate and control the core cooling function during transients, medium LOCAs and small LOCAs. Phase I leedwater and condensate during SAMAs including improvements to plant procedures. and installation of instrumentation to transients and small LOCA and enhance the likelihood of success of operator action in response to accident conditions, have medium LOCAs already been Implemented. No additional Phase IISAMAs were recommended for this subject 24 VDC ECCS Bus B 1.0079 This term represents random failures of the 24VDC ECCS Bus B system. A Phase I SAMA, replacing the 24VDC batteries with 125VDC to 24VOC converters, has already been implemented. Phase II SAMA 047 to protect the power cabinet front internal flooding to further improve reliability of 24VDC ECCS buses was evaluated.

E.1-13

Jonathan Rowley - ER Table E.1-113.doc Pag9e 1-1 Vermont Yankee Nuclear Power Station Applicant's Environmental Report Operating Ucense Renewal Stage Table E.1-3 Correlation of Level 1 Risk Significant Terms to Evaluated SAMAs (Continued)

Risk Significant Terms RRW . Disposition Internal Flooding Initiator, fire 1.0078 This term represents the initiating event of fire protection pipe break (northeast) cascading to protection pipe break (northeast) torus room at El. 252' reactor building. Phase I SAMAs. fire protection system standpipe, was cascading to torus room at El. 252' enhanced to reduce internal flooding risk contribution. No Phase II SAMA was evaluated to reactor building' further reduce this initiator. However. Phase II SAMA 047 to reduce the CDF contribution or internal flooding was evaluated.

Internal Flooding Initiator, SW pipe 1.0073 This term represents the initiating event of SW pipe break in diesel room A, turbine building.

break affecting EDG-1 A, EDG-1 B. Phase I SAMA 047 to reduce the contribution of internal flooding was evaluated.

diesel room A,turbine building Internal flooding Initiator, auxiliary 1.0071 This term represents the initiating event of auxiliary steam break in diesel room A, turbine steam break affecting EDG-1A, building. Phase ! SAMAs to improve doors in the turbine building have already been installed.

turbine building No Phase II SAMA was evaluated to further reduce this inmator. However, Phase II SAMA 047 to reduce the CDF contribution of internal flooding was evaluated..

Internal Flooding Initiator. auxiliary 10067 This term represents the initiating event of auxiliary steam break in diesel room B, turbine steam break affecting EDG-1B, building. Phase! SAMAs to improve doors in the turbine building have already been installed.

turbine building No Phase I1SAMA was evaluated to further reduce this initiator. However, Phase II SAMA 047 to reduce the CDF contribution of internal flooding was evaluated.

24 VDC ECCS Bus A 1 0065 This temi represents random failures of the 24VDC ECCS Bus A system, A Phase I SAMA.

replacing the 24VDC batteries with 125VDC to 24VDC converters has already been installed.

Phase II SAMA 047 to protect the power cabinet from internal flooding to further improve the reliability of 24VDC ECCS buses was evaluated.

Internal Flooding Initiator, SW oipe 1.0059 This term represents the initiating event of SW pipe break in general areas of the turbine break in general areas of turbine building. Phase II SAMA 047 to reduce the contnbution of internal flooding was evaluated.

building E.1-W4

Jonathan Rowley - ER Table E.1-3.doc Page 12 Vermonn Yankee Nuclear Power Station Applicant's Environmenta Revort Operating License Renewal Stage Table E.1-3 Correlation of Level 1 Risk Significant Terms to Evaluated SAMAs (Continued)

Risk Significant Terms RRW Disposition Internal Flooding Initiator, SW pipe 1.0059 This term represents the initiating event of SW pipe break in the HVAC room of the turbine break in HIVAC room of turbine building. Phase II SAMA 047 to reduce the contribution of internal flooding was evaluated.

building Internal Flooding Initiator, 1. 0054 This term represents the initiating event of unisolable SW pipe break in torus room, at El. 213' unisolable SW pipe break in torus of the reactor building. A Phase I SAMA, enhancement of "Loss of Service Water' procedure room, at El. 213"reactor building to contain a mitigation strategy for each break location, has already been implemented. In addition, Phase II SAMA 047 to reduce the contribution of internal flooding was evaluated.

Internal Flooding Initiator, SW pipe 1.0053 This term represents the initiating event of SW pipe break in diesel room B, turbine building.

break affecting EDG-1A. EDG-1B, Phase It SAMA 047 to reduce the contribution of internal flooding was evaluated.

diesel room B. turbine building E.1-15

r-~..- ,- - --

L;5.q !1d Jionatrian R~owley- Revisea Iable E.1-3.doc I Revised Table E.1-3 Correlation of Level 1 Risk Significant Terms to Evaluated SAMAs Risk Significant Terms RRW Disposition Emergency Diesel Generators (A & This term represents random failures of the emergency diesel generators, leading to an s$e B) event. Phase I SAMAs to Improve reliability of the emergency diesel generators by creating a 1.4267 crosstie (A EDG fuel oil supplies and a backup source for diesel c~oling have already been installed. In addition, Phase 11SAMAs 002, 003 and 032 to improve reliability of the EDGs were eveauated.

Loss of Offsrte Power - Initiating This term represents the loss of offsite power initiating event Industry efforts over the last event 1.0951-PC twenty years have led to a significant reduction in plant scrams from all causes. Improvements Crrelated to enhancing oftsite power availability or reliability and coping with plant SBO events PC Plant Centered 1.06053-GR were already Implemented and evaluated during preliminary SAMA screening. Phase II GR Grid Related 1.2985-WR SAMtAs 028. 029. 030,031 033 and 036 for enhancing AC or DC system reliability or to cope with loss of offste power and s$8 events were evaluated.

Wt Weather Related HPCI This term represents random failure of the HPCI system. Phase I SAMAs to improve availability include raising 1.3931 and reliability of the HPCI system that have already beern implemented backpressure trip setpofolm and proceduralizing Intermittent operation. Additional improvements were evaluated In Phase II SAMAs 049. 050%051, 052, 053, and 054.

RCIC This term represents random failures of the RCIC system. Phase I SAMAs to improve 1.3530 .availability and reliability of the RCIC system that have already been installed include raising backpressure trip setpoints and proceduralizlng intermittent operation. Additional improvements were evaluated in Phase II SAMAs 049, 050, 051, 052, 053, and 054.

Operator Action: This term represents operator failure to align the John Deere diesel generator to provide electric and O tr i power to 480VAC bus 9 during a loss of offsite power event. With bus 9 energized Operate( fails to align firewater supplying MCC8B and 98, battery charging is maintained as well as power to RHR valves fire pump for alternate RPV vessel Injection. Phase necessary for aligning the diesel procedures, I SAMAs system and John Deere Diesel for 1 2371 including improvements to plant and Installation of Inslrumentation to enhansethe alternate injection likelihood of success of operator action In response to accident conditions, have already been lipteme*ned. No additional Phase 11SAMAs were recommended for this subject.

ECCS Low Pressure Interlock .1962 This term represents random failures of reactor low-pressure transmitters during transients with

_stuck open SRVs or LOCAs In which random failures prevent all low-pressure injection valves 9 of 28

Jonathan Rowley- Revised Table E.1-3.doc .Paqe 2 1 Revised Table E.1-3 Correlation of Level I Risk Significant Terms to Evaluated SAMAs Risk Signifticant Terms RAW Disposition from odening. Phase II SAMAs.065 and 066 to reduce the risk due Io failure of the ECCS low-pro.sure interlock were evaluated.

Oeprassurization (SRVs and ADS This term represents random failures of the SRVs to open for depressurization during transients Logic) and small LOCAs. Phase I SAMAs to enhance reliability of the SRVs that have already been 1.1582 implemented include adopting symptom based EOPs and SAGs, medifying ADS logic, and upgrading SRV pneumatic components. Additional improvements were evaluated in Phase 11 SAMAs 059 and 060.

Feedwater/Condensate This term represents random failure of the teadwater and condensate injection path. Phase I SAMAs creating connections of existing or alternate water sources to feedwater and been installed to 1,I150 condensate, and installing motor driven feed water pumps, have already increase the availability of injection subsequent to MSIV closure. Many of the Phase if SA:MAs (e.g, 050, 051, 052, 053. and 054) explored potential benefits of enhancing the reliability of high pressure injection systems, Torus Vent via TVS-86 and Rupture This term represents random failures ot components in the cortainmant vent path. A hardened Disk pipe vent path was implemented as a result of the NRC Containment Performance Program to provide a redundant means (of containment heat removal capability. Several Phase I SAMAs 14 regarding the drywell spray system were already installed to provide containment decay heat removal capab~lity by plant design. Therefore. no Phase II SAMAs were proposed to reduce random failure of containment vent path components. However, Phase It SAMA 063 to control containment venting within a narrow pressure band to prevent rapid depressurizatlirt during venting was evaluated.

Less of Feedwater - initiating event This term represents the Initialing event for loss of feedwaler, Modifications to significantly reduce or eliminate the potential for loss of foodwater, such as installing a digital feedwater 1.1072 control system, providing a backup water supply and adding a third feedwater pump, have already been implemented. Many of the Phase I1SAMAs (e.g.. 035,051. 052, 03r, and 054) explored potential benefits for mitigation of this event.

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Jona)hthan RowIley'- Revised, Table E.1-3.doc Page...

Revised Table E.1-3 Correlation of Level I Risk Significant Terms to Evaluated SAMAs Risk Significant Terms RRW Disposition Loss of 4,16KV Bus 3 - initiating This term represents loss of 4.16KV bus 3. Phase I SAMAs to improve 4.16KV bus crosstie evrn 1.11 capability and procedures to repair or replace tailed 4.16KV breakers have already been t1,11050E) implemented. Phase II SAMAs 028, 029, 030. 031,033 and 036 for enhancing AC or DC system retability or to cope with loss of oflsite power and SBO events were evaluated.

Loss of 4.16KV Bus 4 - initiatling This term represents loss of 4.16KV bus 4. Phase I SAMAs to Improve 4.16KV bus crosslie event 1,1006 capability and procedures to repair or replace failed 4.16KV breakers have already been Installed. Phase Ii SAMAs 028, 029, 030, 031,033 and 036 for enhancing AC or DC system reliability or to cope with loss of ofisite power and SBO events were evaluated.

Torus Cooling Mode of RHR & This term represents random failure of the torus cooling mode of the RHR and RHRSW RHRSW systems. Containment spray mode of RHR and fire protection system croestie has already 1.0735 been implemented to provide redundant containment heat removal capab*lity. In addition.

Phase II SAMAs 004, 010 and 017 to improve the reliability of containment decay heat removal were evaluated.

Operator Action: This term represents operator failure to manually open the SRVs for depressurization during transients and small LOCAs. Phase I SAMAs including improvements to plant procedures, and Operator fails to open SRVs for 1.0684 installation of instrumentation to enhance the likelihood of success of operator action In vessel depressurization during response to accident conditions, have already been implemented. No additional Phase It transients and small LOCA SAMAs were recommended for this subject.

.durin tr rnsentsm ei ato ai sh initiation tails. Pha....

Operator Action: {This torm represents operator failure to Initiate HPCRCIC to perform the core cooling function during transients, medium LOCAs, arc small LOCAs when automatic initiation tails. Phase I Operator fails to initiate HPCI/RCIC 0589 SAMAs including improvements to plant procedures, and installation of instrumentation to during transients, mediut and enhance the likelihood of su*,ess of operator action in response to accident conditiona, have small LOCAs already been implemented. No addilionhil Phase 11SAMAs Were recOmmended for this subject.

Operator Action: This term represents operator failure to recognize the need to vent the torus for pressure reduction during loss of containment heat removal accident sequences. Phase II SAMA 063 to Operator tails to recogniZe the need i.0441 control containment venting within a narrow pressure band to prevent rapid containment to vent the torus for pressure depressuuization during venting was evaluated.

reduction _e______ during,_venting_____evaluated.

Containment N,2 1.0373 ThIs term reprosents random taltun) Ofthe containment nitrogen system for SRV operation 110o28

,Jonathan Rowley ReviSed Table E.1-3.doc Paae ~

Pa.qe Revised Table E.1-3 Correlation of Level 1 Risk Significant Terms to Evaluated SAMAs Risk Significant Terms RRW Disposition dunng loss of offsile power. A Phase I SAMA, adding high-pressure nitrogen bottles as a backup to the normal nitrogen supply, has already been installed fokeprove reliability of the containment nitrogen system. Since failure of the SRVs has a larger risk reduction worth than failure of this support system, the benefit derived from Phase II SAMA 060, 'improve SRV design,* is greater than the benefit possible from improving the nitrogen supply system. Also, the cost of adding another nitrogen supply is judged comparable to the cost of modifying the SRVs. Therefore, no Phase it SAMAs were evaluated to further improve reliability of nitrogen supply to the SRVs.

Alternate Cooling This term represents random failure of alternate cooling from the west cooling tower deep basin 1.0373 to the suction of the RHRSW pumps. Phase I1SAMA 064 to improve alternate cooling I capability was evaluated.

Loss of Bus DC-2 and associated These terms represent the initiating event of a complete loss of 125VDC bus DC-2 and random battery - initiating event 1.0367(IE) failures of battery B-1. Phase I SAMAs to Improve alternate battery charging capability, replace existing batteries with more reliable ones and DC bus crosetfe capability have already been 1.0268 installed. Phase I1SAMAs 028, 029, 030, and 033 for enhancing DC system availability and reliability were evaluated.

Loss of Bus DC-1 and associated Those terms represent the initiating event of a complete loss of the 125VDC bus DC-1I and battery - initiating event 1.0360(IE) random failures of battery A-1. Phase I SAMAs to improve alternate battery charging capability, replace existing batteries with more reliable ones, and DC bus crosstle capability have already 1.0226 been installed. Phase II SAMAs 028, 029, 030, and 033 for enhancing DC system availability and reliability were evaluated.

Inadvertent Opening of Relief Valve This term represents the initiating event of inadvertent opening of a relief valve. Improvement

- initiating event 1.0352 of thI SRV design and SRV reseal reliability, to reduce the probability and consequences of this initiating event, were evaluated in Phase I1 SAMAs 055 and 060.

Oporator Action: This term, represents operator failuro to manually open the SRVs to depressurize during a medium LOCA. Phase I SAMAs including improvements to plant procedures, and installation Ooorator tails to open SRVs for 1.0251 of instrumentation to enhance the likelihood of success of operator action in response to vessel depressurization during accident conditions, have aJready been implemented. No additional Phase ft SAMAs were medium LOCA recommended for this subject.

12 of 28 4!l

Jionathan, Rowley--.R'evi-sed Ta~b.e E.1-3.doc P~r~ ~ I I

Revised Table E1-3 Correlation of Level I Risk Significant Terms to Evaluated SAMAs Risk Significant Terms RRW Disposition Internal ReFding Initiator, SW pipe This term represents the initialing event of SW pipe break in torus room, at El. 213' of the reactor break in torus room, at El. 213' of )uilding. Both RCIC and HPCI are assumed to fall due to this flooding initiator. A Phase I SAMA.

the reactor building )nhancemant of "Loss of Service Water* procedure to contain a mitigation strategy for each 1.0247 break location, has already been implemented. In addition. Phase ItSAMAs 049. 50. and 53, to provide an additional high pressure injection pump with independent diesel, install independent AC high pressure injection system, and install an additional active high pressure system to reduce the CDF contribution of this Internal flooding initiator, were evaluated.

Internal Flooding Initiator, SW pipe This term represents the initiating event of SW pipe break in NE ECCS earner room of the break in NE ECCS corner room of reactor building. RFHRloop A and core spray loop A, and both RCIC and HPCI are assumed to the reactor building fail due to this flooding initiator, A Phase I SAMA to increase berm height to prevent flooding of 1.0222 the ECCS corner room has already been installed. In addition, Phase II SAMAs 049, 50. and 53, to provide an additional high pressure injection pump with Independent diesel, Install independent AC high pressure injection system, and install an additional active high pressure system toreduce the CDF contribution of this internal flooding initiator, were evaluated, Transient with PCS available - This term represents the initialing event of a transient with PCS available. Industry efforts over initiating event 1.0221 the last twenty years have led to a significant reduction of plant scrams from all causes. Phase I1SAMA 046 to Improve MSIV design and mitigate the consoquences of this event was evaluated.

Diesel Fire Pump for Alternate This term represents random failure of diesel tire pump P40-lA to provide aitemale RPV Injection vessel injection during a loss of ollsise power event, Phase I SAMAs to use the fire protection 1 ,O1 system as a backup source for containment spray and reactor vessel Injection during loss of otitalte Dower have already been installed to provide redundant capability for RPV injection and heat removal. Phase I1SAMA 064 to provide a croastie tor fire protection from RHRSW system to RHRFloop B to further improve injection capability was evaluated.

Internal Flooding Initiator. SW pipe This term represents the initiating event of SW pipe break in SE EGGS comer room of the break in SE ECCS comer room of reactor building. RHA loop B and core spray loop B, and both RCIC and HPCI are assumed to the reactor building 1.0214 fail due to this flooding initiator. A Paisao I SAMA modifying and sealing the hatch lift points and hatch edges has already been installed to ensure hatches are watertight. in addition, Phase It SAMAs 049, 50, and 53. to provide an additional high pressure injection pump with independent diesel, install independent AC hi28 pressure Injection system, and install an additionai active 13 of 28

!I ~ r~...,.. .=-...- - - -

1 ~JI~cL~ltt -uI~ey - R-evised I able E. 1-3.doc

-i

-~......~.-

Revised Table E.1-3 Correlation of Level I Risk Significant Terms to Evaluated SAMAs Risk Significant Terms RRW Disposition high pressure system toreduce the CDF contribution of this Internal flooding initiator, were evaluated.

RPS This term represents random failure of the reactor protection system. Several Phase I SAMAs to minimize the risks associated with ATWS scenarios have already been installed. No Phase It 1,0189 SAMAs were evaluated to further improve reliability of RPS. However, Phase It SAMAs 057 and 058 to enhance the reliability of the standby liquid control system and improve ATWS capability to mitigate the consequences of this event were evaluated.

Internal Flooding Initiator, SW pipe This term represents the initiating event of SW pipe break at El. 303' of the reactor building.

break at El. 303 o1the reactor Spray from this flooding initiator is assumed to affect the ECCS 24V DC distribution panal. A building 1.0171 Phase I SAMA. adding chase berms at elevation 303', has already been installed, in addition.

Pnase I SAMA 047, to shield the ECCS power cabinet to reduce the CDF contribution of this Internal flooding initiator was evaluated.

Bus 2 (supplied by SU XFMR) This term represents the initiating event of a complete loss of oftslta power Irom the 345 KV 4.16KV switchyard and 115 KV line. Phase I SAMAs to improve 4.16KV bus ctosstie capability, 1,0164 procedures to repair or replace failed 4.16KV breakers and provide connection to an alternate source of oftsite power have already been installed. Phase It SAMAs 028, 029, 030,031,033 and 036 for enhancing AC OrDC system reliability or to cope with loss of offsite power and WO events were evaluated.

Operator Action: This term represents operator failure to align condensate transfer pump to inject via LPCI or core spray lines for alternate injection. Phase I SAMAs including improvements to plant Operator fails to align a condensate procedures, and installation of instrumentation to enhance the likelihood of success of operator transfer pump to Inject via LPCI or 1.0166 action in response to accident conditions, have already been implemented, No additional core spray lines for alternate Phase Ii SAMAs were recommended for this subject.

injection Operator Action: This term represents operator failure to align water from the west cooling tower deep basin to the suction of the RHRSW pumps to cool a number of loads normally cooled by the service Operator fails to initiate alternate water system. Phase I SAMAs including improvements to plant procedures, and installation of 1.0144 cooling mode from the cooling instrumentation to enhance the liketlihood of success of operator action in response to accident tower deep basin conditions, have already been implemented, No additional Phase I1SAMAs were recommended for this subject.

14of28 14 of 28

Jonathan Rowley - Rev~~ al ae Revised Table E.1-3 Correlation of Level I Risk Significant Terms to Evaluated SAMAs Risk Significant Terms RRW Disposltion Internal Flooding Initiator, SW pipe This term represents the initiating event ot SW pipe break in NE ECCS corner room of the break (rnorth) affecting MCCs and reactor building. Spray from this flooding initiator can affect the RCIC atfernate shutdown ECCS in NE comnr room of the transfer switch panel and local starter panel for V13-16. RCIC is also subject to flooding within reactor building 12 to 15 minutes. Inaddition, the spray event can affect HPCI local starter panel for V23-16.

1.0137 HPCI is also subject to flooding within 30 minutes. A Phase I SAMA. enhancement of 'Loss of Service Water" procedure to contain a mitigation strategy for each break location, has already been implemented. in addition, Phase if SAMAs 049, 50, and 53, to provide an additional high pressure injection pump with independent diesel. install independent AC high pressure injection system, and install an additional active high pressure system to reduce the CDF contribution of this internal flooding Initiator, were evaluated.

Bus 1 (mupplied by SU XFMIR) This term represents the Initiating event of a complete loss of offsile power from the 345 KV 4.16KV switchyard and 115 KV line. Phase I SAMAs to improve 4.16KV bus crosstie capability, an alternate 1.0096 procedures to repair or replace failed 4.16KV breakers and provide connection to source of offsite power have already been Installed. Phase If SAMAs 028, 029, 030, 031,033 and 036 for enhancing AC of DC system reliablIly or to cope with loss of offaite power and SBO events were evaluated.

Vernon Tie IThis term represents random failure of Vernon tie line circuit breakers to close and operator failure to close two breakers from the control room. Phase I SAMAs fo provide an alternate source of offsite power. proceduratlie stops in recovery of offsite power after SBO, and protect 1.0129 control cable of Vernon tilebreakers have already been installed. No Phase II SAMtAs were evaluated to further Improve reliability of the Vernon tie. However. Phase II SAMAs 028, 029, 030, 031,033 and 036 for enhancing AC or DC system availability or reliability to cope with the loss of offsito power and SBO events were evaluated.

Internal Flooding Initiator, fire This term represents iho initiating event of fire protection pipe break in torus room, at El. 232 of protection pipe break in upper RCIC the reactor building.

room at El. 232' This flooding initiator fails RCIC since flood water and spray Is delivered to the lower RCIC area.

1.01211 A Phase I SAMA, to provide a reliel path to relieve water accumulation in the upper RCIC to lower RCIC area before floor failure, has already been implemented. Phse II SAMAs 049, 50, and 53, to provide an additional high pressure Injection pump with independent diesel, install

'I. independent AC hiath pressure injection system, and install an additional active high pressute 150of28

SJonathan Rowley - Revised Table E.-1-3.dec Revised Table E.1-3 Correlation of Level 1 Risk Significant Terms to Evaluated SAMAs Risk Significant Terms RRW Disposition system to reduce the CDF contribution of this internal flooding initiator, were evaluated.

ATWS with MSIV Closed - Initiating This term represents the ATWS initiating event. Several Phase I SAMAs to create a boron event Injection path through CRD, increase boron concentration, and provide RPT, ARI, and FW trip 1.0100 to miniamize the risks associated with ATWS scenarios have already been installed. Inaddition, Phase I SAMAs 057 and 058 to enhance reliability of the standby liquid control system and improve ATWS capability to mitigate the consequences of this event were evaluated.

Internal flooding Initiator, SW pipe This term represents the initiating event of SW pipe break at El. 280' of the reactor building. A break in affecting instrument panels major break in the service water system 18Ediameter supply piping an El. 280' (north) has the and 480V MCC, at El. 280' of the potential to fail ECCS instrument panel 68 (S2), channels A and C. Division S2 (channels A and reactor building 1 0090 C) of ECCS signal instruments are failed as a result of this flood event. A Phase I SAMA.

enhancement of "Loss of Service Water' procedure to contain a mitigation strategy for each break location, has already been Implemented. In addition, Phase It SAMA 047, to shield the ECCS power cabinet to reduce the CDF contribution of this internal flooding initiator was evaluated, Operator Action: This term represents operator failure to start TBCCW pump locally from the motor control panel and establish cooling to BOP components for RPV makeup and heat removal, Phase I SAMAs Operator lails to start a TBCCW 1.0083 including Improvements to plant procedures, and installation of instrumentation to enhance the pump likelihood of success of operator action in response to accident conditions, have already been implemented. No additional Phase I1SAMuAs were recommended for this subject Operator Action: This term represents operator lailure to initiate SLC during an ATWS without main condenser.

Operator fails to initiale SLC during 1.C0083 Phase I SAMAs including improvements to plant procedures, and installation of instrumentation Operator si0 Intiate mn oduingr to enhance the likelihood of success of operator action in response to accident conditions, have an ATWS without main condenser already been implemented. No additional Phase it SAMAs wore recommended for thls subject Loss at PCS - initiating event This term represents the Initiating event of a loss of PCS. Industry elforts over the last twenty 1.0083 years have led to a significant reduction of plant scrams Irom all causes. Phase II SAMA 046 to improve MSIV design and mitigate the consequences of this event was evaluated.

Stuck Open SRVs initiating event -0012 This term represents the Initiating event of stuck open SRVs. improvement of SRV reseat

_t__k__e___R___n__i__ngeven 1.0082__ reliability and SRV design were evaluated in Phase II SAMAs 056 and 060.

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Jonathan Rowley- Revised Table E. 1-3.doc P~tn~J Revised Table E.1 -3 Correlation of Level 1 Risk Significant Terms to Evaluated SAMAs Risk Significant Terms RRW Disposition Internal Flooding Initiator, This term represents the initiating evont of circulating water pipe break in the turbine building.

circulating water pipe break in This break causes failure of turbine bypass and the main cowdenser. It results In degraded turbine building circulating water flow which leads to failure of foodwater and condensate. Phase I SAMAs to improve inspeclion of expension joints on the main condenser and to change procedures to 1.0081 reduce the probability of a circulating water piping break have already been implemented.

Phase I SAMAs 049. 50. and 63, to provide an additional high pressure injection pump with Independent diesel, instat independent AC high pressure injection system, and install an additional active high pressure system to reduce the CDF contribution of this internal flooding initiator, were evaluated.

Internal Flooding Initiator, SW pipe This term represents the initiating event of SW pipo break in the intake structure. This break break In intake structure causes significant flow diversion. The flow diversion causes circulating water. TBCCW.

1.0074 feedwater and condensate system failures. Phase II SAMAS 049. 50, and 53. to provide an additional high pressure injeoton pump with independent diesel, install independent AC high pressure injection system, and install an additional active high pressure system to reduce the CDF contribution of this internal flooding Initiator, wore evaluated, Loss of Service Water - initiating Those terms represent random passive failures of the service water system and the initiating event 1,0065 event of a complete loss of the service water system, Enhancement of the service water system was evaluated in Phase I1SAMA 001.

24 VOC ECCS Bus B This term represents random fatures of tho 24VDC ECCS Bus B system. A Phase I SAMA, 1.0050 replacing the 24VDC batteries with 125VOC to 24VDC converters, has already been implemented. Phase II SAMA 047 to protect the power cabinet from internal flooding to further improve reliability of 24VDC ECCS buses was evaluated.

Operator Action: This term represents operator failure to align feedwater end condensate Injection to perform the Phase I SAMAs Operator fails to initiate and control core cooling function during transients, medium LOCAs and smti LOCAs.

to enhance the feedwater and condensate during 1.0349 including Improvements to plant procedures, and installation of instrt*mentation aLOCA and likelihood of success ot operator action in response to accident conditions, have already been transients and small implemented. No additional Phase )I SAMAs were recommended for this subject medium LOCAs 24 VOC ECCS Bus A 1.0042 This term represents random lfalures of the 24VDC ECCS Bus A system. A Phase I SAMA.

replacing the 24VDC batteries with 125VDC to 24VDC converters has already been installed, 17 of 28

' Jonathan Rowley - Revised Table E. 1-3.doc- Pae 0 Revised Table E.1-3 Correlation of Level 1 Risk Significant Terms to Evaluated SAMAs Risk Significant Terms RRW Disposition Phase II SAMA 047 to protect the power cabinet from internal flooding to further improve the reliabitity of 24VD0 ECCS buses was evaluated.

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