ML071990501

(PA-LR) Pg 2-38 Info

ML071990501
Person / Time
Site:	Vermont Yankee File:NorthStar Vermont Yankee icon.png
Issue date:	06/18/2007
From:	Hamer M Entergy Corp
To:	Rowley J NRC/NRR/ADRO/DLR/RLRA
References
TAC MD2297
Download: ML071990501 (25)

Text

Jonathan Rowley - Pg 2-38 info, Page 1 From:

"Hamer, Mike" <mhamer@entergy.com>

To:

"Jonathan Rowley" <JGR@nrc.gov>

Date:

06/18/2007 12:02:32 PM

Subject:

Pg 2-38 info The PNP SER states:

"The staff examined the applicant's environmental report, Appendix E, Attachment E.1, "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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Pg 2-38 info 06/18/2007 12:01:38 PM "Hamer, Mike" <mhamer(ýentergy.com>

mhamerientergy.com Recipients nrc.gov TWGWPO03.HQGWDOO1 JGR (Jonathan Rowley)

Post Office TWGWPO03.HQGWDO01 Files MESSAGE TEXT.htm Table RAI. 1-3.doc ER Table E. 1-3.doc Revised Table E. 1-3.doc Mime.822 Options.

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JonaIlauiri.Rovviey -

uIabe i-vu1 -j.aoc P::rlpa I 1 Table RAI.1-3 Summary of Major PSA Model Versions Model CDF' LERF IPE 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 VYOORO 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-06 VY02R6 7.77E-06 2.29E-06 VY02R7 7.63E-66 2.23E-06 VY02R8 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 1 With the exception of the original IPE, IPEEE, and version Wi118 CDF and LERF values, subsequent VYNPS model version updated CDF and LERF values include the combine contributions from transients, LOCAs and Internal floods Initiators,

J o n a th a n...

R o w le y...

E R................Ta b le.................

o P g Jonathan Rowley - ER Table E. 1 -3.doc Page 1 1 Vermont Yankee Nuclear Power Station Applicant's Environmental Report Operatina License Renewal Siage 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 imlrove availability and reliability of the HPCI system that have already been implemented include raising hackpressure trip selpoints and proceduralizing intermittent operation. Additional improvements were evaluated in Phase 11 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 backpressure trip 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 tow-pressure interlock were evaluated.

Depressurization (SRVs and ADS 1.2724 This term represents random failures of the SRVs to open for depressunzation 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 pneumatic components. Additional improvements were evaluated in Phase It SAMAs 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 Ta.ble E. 1-3.doc Pa 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 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 II SAMAs were recommended for this subject.

Loss of Oftsite Power - initiating 1.0951-This term represents the loss of offsite power initiating event. Industry efforts over the last event PC twenty years have ted to a significant reduction in plant scrams from all causes. Improvements PC - Plant Centered 1.0605-related to enhancing offsite power 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 $BO 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 depressurization 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 crosstlie event capatility and procedures to repair or replace failed 4.16KV breakers have already been implemented. Phase 11 SAMAs 028, 029, 030, 031, 033 and 036 for enhancing AC or DC system reliability or to cope with loss of ofisite power and S80 events were evaluated.

E.1-5

Jonfiathn-`Rowley - ER Table E. 1-3.doc Pg_

Vermont Yankee Nuclear Po'wer 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 SBO (A & B) event. Phase I SAMAs to improve reliability of 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 I SAMAs 002, 003 and 032 to improve reliability of the EDGs were evaluated.

Loss of 4.16KV Bus 4 - initiating 1.0756 This term represents loss of 4,16KV bus 4. Phase I SAMAs to Improve 4.16KV bus crosstie 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 HPCIIRCIC to perform the core cooling function Operator fails to initiate HPCIURCIC during 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 SAMAs were recommended for this

subject, Operator Action:

1.0660 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 durng a loss of offsile power event-Wth bus 9 energized and system and John Deere Diesel for supplying MCCB and gB, 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

J Uonathan Rowley-ER Table E.1-3,doc Page 4 "

Vermont Yankee Nuclear Power Station Applicantfs 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 N2 1.0553 This term represents random failure of the containment nitrogen system for SRV operation dunng loss of offsite power. A Phase I SAMA, adding high-pressure nitrogen bottles as a backup to the normal nitrogen supply, 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 support system, the benefit derived from Phase I1 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 II SAMAs were evaluated to further improve reliability of nitrogen supply to the SRVs.

Diesel Fire Pump and John Deere 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 alternate RPV vessel injection during a loss of ottsite power event. Phase I SAMAs to use the tire protection system as a backup source for containment spray and reactor vessel injection during loss of offsite power have already been installed to provide redundant capability for RPV injection and heat removal. Phase II SAMA 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-initiating event 1.0264 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 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

Jonathan Rowley-ER Table E.1-3.doc Page6 jj 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 Loss of Bus DC-2 and associated 1,0517(IE)

These terms represent the initiating event of a complete loss of 125VDC 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 11 SAMAs 028, 029, 030, and 033 for enhancing DC system availability and reliability were evaluated.

Torus Cooling Mode of RHR &

1.0515 This term represents random failure of the torus cooling mode of the RHR and RHRSW RHRSW systems. Containment spray mode of RHR and tfre protection system crosstie has already been implemented to provide redundant containment heat removal capability. In addition, Phase It SAMAs 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 depressurization 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 11 SAMAs were recommended for this subject Loss of Service Water - initiating 1.0102 These terms represent 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 11 SAMA 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 I1 SAMA 047 to reduce the CDF contribution of internal flooding was evaluated.

E.1-8

Jonathan Rowley - ER Table E.1-3.doc Page 6 I 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 Operator 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 I1 SAMA 063 need to vent the torus for pressure to control containment venting within a narrow pressure band to prevent rapid containment reduction depressurization during venting was evaluated.

Internal Flooding Initiator, SW pipe 1.0357 This term represents the initiating event of SW pipe break in NE ECCS corner room of the break in NE ECCS corner room of reactor building. A Phase i SAMA to increase berm height to prevent flooding of the ECCS the reactor building corner room has already been installed. In addition, Phase I1 SAMA 047 to reduce the COF contribution of internal flooding was evaluated.

Internal Flooding Initiator, SW pipe 1.0343 This term represents the initiating event of SW pipe break in SE ECCS corner room of the break in SE ECCS comer room of reactor building. A Phase I SAMA modifying and sealing the hatch lift points and hatch edges the reactor building has already been installed to ensure hatches are watertight. In addition, Phase II SAMA 047 to reduce the CDF contribution of internal flooding was evaluated.

Internal Flooding Initiator, SW pipe 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 crosstle 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 oftsite power and SBO events were evaluated.

E.1-9

I.pnthan Rowl~ey - ER Table E. 1-3.doc PageJi1 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 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 II SAMAs were evaluated to further improve reliability of RPS. However, Phase II 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.

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 or plant scrams from all causes. Phase II SAMA 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 in response to accident conditions, have already been implemented. No alternate injection additional Phase II SAMAs were recommended for this subject.

Operator Action 1.G257 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 RHRSW 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 II SAMAs were recommended for this subject.

E.1-t0

Jonathan Rowley - ER Table E. 1-3.doc Page 8P Vermont Yankee Nuclear Power Sittion Applicant's Environmental Repon Operating License Renewal Stage Table E.1-3 Correlation of Level 1 Risk Significant Terms to Evaluated SAMAs (Continued)

Risk Significant Terms RRW Disposition FeedwaterlCondensate 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 reliability of high pressure Injection systems.

Internal Flooding Initiator, SW pipe 1.0218 This term represents the initiating event of SW pipe break in NE ECCS corner (Dom of the break (north) affecting MCCs and reactor building. A Phase I SAMA, enhancement ot 'Loss of Service Water' procedure to ECCS in NE comer 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 CDF 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 arzemate source of offsite power have already been installed. Phase 1t 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 Vernon tie line circuit breakers to close and operator failure to close two breakers from the control room. Phase I SAMAs to provide an alternate source of oftsite power, proceduralize steps in recovery of offsite power after 580, and protect control cable of Vernon liebreakers have already been installed.

No Phase I SAMAs were evaluated to further improve reliability of the Vernon tie. However, Phase 11 SAMAs 028ý 029, 030. 031, 033 and 036 for enhancing AC or DC system availability or reliability to cope with the loss of offsite power and SBO events were evaluated.

E.1-11

I Jonathan Rowley-ER Table E.1-3.doc Page 94 Venmoni Yankee Nuclear Power Station Applicant's Environmental Report Operating Ucense Renewal Staqe Table E.1-3 Correlation of Level 1 Risk Significant Terms to Evaluated SAMAs (Continued)

Risk Significant Terms RRW Disposition Inmemal 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 AIWS initiating event. Several Phase I SAMAs to create a boron event Injection path through CRD, increase boron concentration, and provide RPT, ARI. and FA' 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 AT0.1S 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. In addition, Phase 11 SAMA of the reactor building 047 to reduce the CDF contribution of internal flooding was evaluated Altemate 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 It SAMA 064 to improve alternate cooling capability was evaluated.

Stuck Open SR[s - 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.

Operator Action:

1.0133 This term represents 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 II SAMAs were recommended for this subject E.1-12

Jonathan R"o-1-*ERTble E.-'3".d"--c'-

Page 10 I Vermont Yankee Nuclear Power Station Applicant's Environmental Report Operatng 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, 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 I1 SAMA was evaluated to further reduce this initiator.

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

Operator Action:

1.0130 This term represents operator failure to initiate SLC during an ATWS without main condenser.

Operator fails to initiate SLC during Phase I SAMAs including improvements to plant procedures, and Installation of an ATWS 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 I1 SAMAs were recommended for this subject Internal Flooding Initiator, SW pipe 1.0119 This teait represents the initiating event of SW pipe break in the intake structure. Phase II 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 tie last twenty years have ted 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 Ooerator fails to initiate and control the core cooling function during transients, medium LOCAs and small LOCAs. Phase I feedwater 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 It SAMAs 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 24V0C 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

J on at ha n-RobWl e-y--'ER T-alblIe E. 1

.- 3 1d 1o c Page 11' I 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 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 of 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 I1 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-1 A, building. Phase I SAMAs to improve doors in the turbine building have already been installed.

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

Internal Flooding Initiator. auxiliary 1.0057 This term represents the Initiating event of auxilIary steam break in diesel room B, turbine steam break affecting EDG-1 8, building. Phase I SAMAs to improve doors in the turbine building have already been installed.

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

24 VDC ECCS Bus A 1.0065 This term 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 It 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 pipe 1.0059 This term represents the initiating event o1 SW pipe break in general areas of the turbine break in general areas of turbine building. Phase II SAMA 047 to reduce the contribution of internal flooding was evaluated.

building E.1-4

Jonathffan_--R~ow'ley -ER Table-E.A-1-3.oc Pag 12...

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 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 HVAC 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. 2137 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

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Paae 1 ?1 Revised Tabie E.1-3 Correlation of Level I Risk Significant Terms to Evaluated SAMAs Risk Significant Terms RRW Disposition Emergency Diesel Generators (A &

This term represents ratndom talures of the emergency diesel generators, leading to an $80

8) event. Phase I SAMAs to Improve reliability of the emergency diesel generators by creating a 1.4267 crosstie of EOG fuel oil supplies and a backup source for diesel cooling have already been installed. In addition, Phase HI SAMAs 002, 003 and 032 to improve reliability of the EDGs were evaluated.

Loss of Offsite 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 related to enhancing offsite power availability or reliability and coping with plant SBO events PC Plant Centered 1,0605-GR were already Implemented and evaluated during preliminary SAMA screening.

Phase 1i GR Grid Related 1,2985-WR SAMAs 028, 029, 030, 031,033 and 036 for enhancing AC or DC system reliability or to cope WA Weather Related with loss of offsite power and SBO events wore evaluated.

HPCI This term represents random failure of the HPCI system. Phase I SAMAs to improve ava~lability

.39~31 and reliability of the HPCI system that have already been implemented include raising backpressure trip aetpoints and proceduralizing intermittent operation. Additional improvements were evaluated in Phase 11 SAMAs 049,050,051.062,063, and 054.

RCIC This term represents random taltures of the RCIC system. Phase I SAMAs to improve 1.3530 lavailability and reliability of the'.ICIC system that have already been installed include raising backpressure trip setpolnts and procoduralizing 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 power to 480VAC bus 9 during a loss of offsite power event. With bus 9 energized and Operator fails to align firewater supplying MCC88 and 98, battery char'ging is maintained as well as poxwer to RHR valves system n Joh Deeren 12371 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 Implemonted. No additional Phase II SAMAs were recommended for this subject.

ECCS Low Pressure Interlock 1 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 9of28

I Jonathan Rowley-Revised Table E.!-3.doc PaQe 2 I Revised Table E.1-3 Correlation of Level I Risk Significant Terms to Evaluated SAMAs Risk Significant Terms RRW Disposition from ooening. Phase It SAMAs 065 and 066 to reduce the risk due to failure of the ECCS low-pressure interlock were evaluated.

Depressurization (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, modifying ADS logic, and upgrading SRV pneumatic components, Additional improvements were evaluated In Phase II SAMAs 059 and 060.

Feedwater/Condersate This term represents random failure of the teedwater and condensate injection path. Phase I SAMAs creating connections of existing or alternate water sources to feedwater and condensate, and installing motor driven teed water pumps, have already been installed to 1150 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 reliability of high pressure injection systems.

Torus Vent via TVS-B6 and Rupture This term represents random failures of componentS in the containment vent path. A hardened 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 1.1149 regarding the drywall spray systaem were already installed to provide containment decay heat removal capabitty by plant design. Therefore. no Phase II 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 depress urizatlon during venting was evaluated.

Loss of Feedwatar - initiating event This term represents the initiating event for loss of foadwatef. Modifications to significantly reduce or eliminate the potential for loss of feedwater, such as installing a digital feedwater 1.1072 control system, providing a backup water supply and adding a third feedwater pump, have already boen Implemented. Many of the Phase II SAMAs (e.g., 035.051.052, 053. and 054) explored potential benefits for mitigation of this event.

100128

Joatan Ro ley-Rvise6C~I e E1 -3.doc Pg3 Revised Table E.1-3 Correlation of Level I Risk Sigintlicant 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 crosstle event 11051IE) capability and procedures to repair or replace tailed 4.16KV breakers have already been implemented. Phase I1 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.

Loss of 4.16KV Bus 4-initiating This term represents loss of 4.16KV bus 4. Phase I SAMAs to Improve 4.16KV bus crosstie event 1.10W capability and procedures to repair or replace tailed 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 ovents were evaluated.

Torus Cooling Mode of RHR &

This term represents random failure of the torus cooling mode of the RHR and RHRSW RHf3SW systems. Containment spray mode of RHR and fire proaction system crosstle has already 1.0735 been implemented to provide redundant containment heat removal capability, 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 Operaeldrfails tosopen SRa s for i

.0684 installation of instrumentation to enhance the likelihood of success of operator action In vessel dopressurizalton during response to accident conditions, have already been implemented. No additional Phase II trarnsients and smell LOCA SAMAs were recommended for this subject.

Operator Action:

This term represents operator failure to Initiate HPCVRCIC to perform the core cooling lunction Operator falls o initiate HPC/tCIC during transients, medium LOCAs, and small LOCAs when automatic initiation fails, Phase I duringtoransoienitsatemePium d

1.0589 SAMAs Including improvements to plant procedures, and installation of instrumentation to during transients, medium n enhance the likelihood of success of operator action in response to accident conduitons, have small LOCAs already been implemented. No additional Phase II SAMAs 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 renmoval accident sequences. Phase II SAMA 063 to Operator fails to recognize the need 1.0"t control containment venting within a narrow pressure band to prevent rapid containment to vent the torus for pressure depressurization during venting was evaluated.

reduction Containment Nh 1.0373 This term represents random failure of the containment nitrogen system for SRV operation 11 of 28

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Revised Table E.1-3 Correlation of Level 1 Risk Significant Terms to Evaluated SAMAs Risk Significant Terms RRW Disposition during loss of offsite power. A Phase I SAMA, adding high-pressure nitrogen bottles as a backup to the normal nitrogen supply, has already been instated to improve 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 I1 SAMA 060, *improve SAV 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 II SAMAs were evaluated to further improve reliability of nitrogen supply to the SRVs.

Alternate Cooling This term represeMs random failure of alternate cooling from the west cooling tower deep basin 1.0373 to the suction of the RHFIRSW pumps. Phase II SAMA 064 to improve alternate cooling 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 crosstle capability have already been 1.0268 installed. Phase Ii SAMAs 028, 029, 030, and 033 for enhancing DC system availability and reliability were evaluated.

Loss of Bus DC-I and associated Those terms represent the initiating event of a complete loss of the 125VDC bus DC-1 and battery - ititiatirn 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 It 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 inadverlent opening of a relief valve, Improvement

- initiating event 1.0352 of the SRV design and SRV reseat reliability, to reduce the probability end consequences of this initialing event. were evaluated in Phase It SAMAs 055 and 060.

Operator Action:

This term represents operator failure to manually open the SRVs to depressurize during a medium LOCA. Phase I SAMas including improvements to plant procedures, and installation Operator fails to open SRVs for 1.0251 of instrumentation to enhance the tkelihood of success of operator action in response to vessel depressurzation during accident conditions, have already been implemented. No additional Phase II SAMAs were medium LOCA recommended for this subject.

12 of 28

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Revised Table E.1-3 Correlation of Level I Risk Significant Terms to Evaluated SAMAs Risk Significant Terms RRW Disposition Internat Flooding Initiator, SW pipe This term represents the Initiating event of SW pipe break in torus room, at El. 213T of the reactor break in torus room, at El. 213T of

)uilding. Both RCIC and HPCI are assumed to fail due to this flooding initiator, A Phase I SAMA, the reactor building

)nhancernent of "Loss of Service Water" procedure to contain a mitigation strategy for each 147 reak localion, has already been Implemented. In addition, Phase 11 SAMAs 049. 50. and 53, to rovide an additional high pressure Injection pump with independent diesel, Install independent C high pressure injection system, and install an additional active high pressure system to educe the CDF contribution of this internal flooding initiator, were evaluated.

Intemat Flooding Initiator, SW pipe This term represents the initiating event of SW pipe break In NE ECCS comer room 0f the break in NE ECCS corner room of reactor building. RHR loop 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 t.0222 the ECCS comer room has already been installed. In addition, Phase It 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 loreduce the COF contribution of this internal flooding initiator, were evaluated.

Transient with PCS available -

This term represents the initiating 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 I SAMA 046 to improve MSIV design and mitigate the consequences Of this event was evaluated.

Diesel Fire Pump for Alternate This term represents random failure 01 diesel fire pump P40-1A to provide elternate RPV Injection vessel injection during a toss of olfsite power event. Phase I SAMAS to use the fire protection 1.0218 system as a backup source for containment spray and reactor vessel injection during lose of oftslte power have already been installed to provide redundant capability for RPV injection and heat removal. Phase II SAMA 064 to provide a crosstle for fire protection from RHRSW system to RHR loop 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 ECCS comer room of the break in SE ECCS comer room of reactor building. RHFI 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 Phase 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, Instll. independent AC hig2 8

ressure injecton system, and istall an additionel ec've 13 of 28

I Jonathan Rowley - Revised Tabl E1-3doc 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 COF 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 reliabitity of tPS. However, Phase it SAMAs 057 and 058 to enhance the retiability 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' of the reactor Spray from this flooding initiator is assumed to affect the ECCS 24V DC distribution panel. A building 1.0171 Phase I SAMA. adding chase berms at elevation 303', has already been installed. In addition.

Phase II 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 oftsits power from the 345 KV 4.16KV switchyard and 115 KV line. Phase I SAMAs to improve 4.16KV bus crosstfie capability, procedures to repair or replace failed 4.16KV breakers and provide connection to an alternate 1.0184 source of offslte power have already bee installed. Phase II SAMAs 028,029,030,031,M33 and 036 for enhancing AC or DC system reliability or to cope with loss of offsite power and SO events were evaluated.

Operator Action:

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

injection Operator Action:

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

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Page7, Revised Table E.1-3 Correlation of Level I Risk Significant Terms to Evaluated SAMAs Risk Significant Terms RRW Disposition Internal Flooding Initiator. SW pipe This term represents the initiating event of SW pipe break in NE ECCS corner room of the break (north) affecting MCCs and reactor building. Spray from this flooding Initiator can effect the RCIC alternate shutdown ECCS in NE comer 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. In addition, 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 mitlgatlon strategy for each break location, has already been implemented. in addition, Phase II SAMAs 049, 50, and 53, to provide an additional high pressure inrection pump with independent diesel, install Independent AC high pressure injection system, and misalt an additional active high pressure system Io reduce the CDF contribution of this internal flooding Initiator, were evaluated.

Bus 1 (supplied by SUJ XiFMA)

This ferm represents the initiating event of a comnpltele loss of offalte, power from the 345 KV 4.16KV switchyard and 115 KV line, Phase I SAMvAs to improve 4.16KV bus crosslie capability, procedures to repair or replace failed 4.16KV breakers and provide connection to an alternate t0096 source of offsite power have already been installod. Phase 11 SAMAs 028, 029, 030, 031,033 and 036 for enhancing AC or DC system reliability of to cope with loss of oftsite power and SBO events were evaluated.

Vernon Tie This 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 SAWAs to provide an alternate source of offsite power. proceduralize stops in recovery of offsite power after SUO. and protect 1.0129 control cable of Vernon tiebreakers have already been installed.

No Phase II SAMAs were evaluated to further improve reliability of the Vernon tie. However, Phase It SAM.As 028, 029, 030, 031,033 and 036 for enhancing AC or DC system availability or reliability to cope with the loss of offsite power and SBO events were evaluated, Internal Flooding Initiator, fire This term represents Iho initiating event of fire protection pipe break in lotus room, at El. 232' of protection pipe break in upper RCIC the reactor building, room at El. 232' This flooding initiator tails RCIC since flood water and spray is delivered to the lower RCIC area, 1.0111 A Phase I SAM/A, to provde a reliet path to relieve wafer accumu~alaon in the upper RCIC to lower RCIC area before flor failure, has already been Implemented. Phase II SAMAs 049, 60, 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 150(28

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to 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 terra 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 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 ftlooding Initiator, SW pipe This term represents the initiating event of SW pipe break at El. 280' of the reactor building. A break in affectng Instrumerit panels major break in the service water system 18 diameter supply piping on El. 280 (north) has the and 480V MCC, at El. 280' of the potential to tail ECCS instrument panel 6B (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 evoent. 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 11 SAWA 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 fails to start a TBCCW 1 -UM3 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 it SAMAs were recommended for this subject Operator Action:

This term represents operator lailure to initiate SLC during an ATWS without main condenser.

Phase I SAMAs including improvements to plant procedures, and installation of Instrumentation Operator tails to initiate SLC luring 1.0083 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 I1 SAMAs were reconmmended for this subject Loss of PCS - initiating event This term represents the initiating event of aloss of PCS. Industry efforts over the last twenty 1.0083 years have led to a significant reduction of plant scrams from all causes. Phase 11 SAMA 046 to improve MSIV design and mitigate the consequences of this event was evaluated.

Stuck Open SRVs initiating event 160082 This term represents the Initiating event of stuck open SRVs. Improvement of SRV reseat reliability and SRV design were evaluated in Phase it SAMAs 055 and 060.

16 of 28

I Jonathai.Rowley-_Revised.TableE.1-3.doc

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Paoi~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 event of circulating water pipe break in the turbine building, circulating water pipe break in This break causes failure of turbine bypass and the main condenser. It results In degraded turbine building circulating water flow which leads to failure of feedwater and condensate. Phase I SAMAs to improve Inspection of expansion joints or the main condenser and to change procedures to 1.0081 reduce the probability of a circulating water piping break have already been implemented.

Phase It SAMAs 049, 50, and 63. to provide an additional high pressure injection pump with independent diesel, intall 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 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 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.

Loss of Service Water - initiating Ithese terms represent random passive failures of the servIce water system and the initiating event 1.0065 event of a complete less of the service water system. Enhancement of the service water system was evaluated in Phase II SAMA 001.

24 VOC ECCS Bus B This term represents random lailures of the 24V0C ECCS Bus B system,. A Phase I SAMA, 1,0050 replacing the 24VDC batteries with 125VDC to 24VDC converters, has already been implemented. Phase It SAMA 047 to protect the power cabinet from Internal flooding to further Improve reliability of 24VDC ECCS buses was ovaluated.

Operator Action:

This term represents operator failure to align feedwater and condensate Injection to perform the Operator fails to initiate and conltro core cooling function during transients, medium LOCAs and small LOCAs. Phase I SAMAs feedwater and condensate during 1 0049 including Improvements to plant procedures, and installation of Instrtumentation to enhance the likelihood of success of operator action in response to accident conditions, have already been transients and small LOCA and implemented. No additional Phase II SAMAs were recommended for this subject medium LOCAs 24 VDC ECCS Bus A 1.0042 This term represents random failures of the 24VDC ECCS Bus A system. A Phase I SAMA, recirvg the 24VDC batteries with 125VDC to 24Vt)C converters has already been installed.

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Jonathan Rowley-Reid TableE.13.doc Page. 10 isPaeg Table-Revised Table E.1-3 Correlation of Level 1 Risk Slgnfttcant Terms to Evaluated SAMAs 18 of 28