ML081000079

Request for Enforcement Discretion - Technical Specification 3.8.1 Required Actions F.1 and F.2

ML081000079
Person / Time
Site:	Palisades
Issue date:	04/08/2008
From:	Schwarz C Entergy Nuclear Operations, Entergy Nuclear Palisades
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
LTR-PSA-08-01
Download: ML081000079 (100)

Text

Enteigy April 8, 2008 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 Palisades Nuclear Plant Docket 50-255 License No. DPR-20 Entergy Nuclear Operations, Inc.

Palisades Nuclear Plant 27780 Blue Star Memorial Highway Covert, MI 49043 Request for Enforcement Discretion - Technical Specification 3.8.1 Required Actions F.1 and F.2

Dear Sir or Madam:

This letter confirms the results of the teleconference that was conducted between Entergy Nuclear Operations, Inc. (ENO) and the Nuclear Regulatory Commission NRC at 1845 EDT, on April 4, 2008, in which ENO requested the NRC to exercise enforcement discretion from compliance with the requirements of Technical Specification (TS) 3.8.1 Required Actions F.1 and F.2, for Palisades Nuclear Plant (PNP). TS 3.8.1, "AC Sources - Operating," Limiting Condition for Operation 3.8.1a, requires two operable qualified circuits between the offsite transmission network and the onsite class 1 E AC electrical power distribution system. TS 3.8.1, Required Action A.2 requires that, with one offsite circuit inoperable, restore the offsite circuit to operable within the 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />. TS 3.8.1, Required Actions F.1 and F.2 require that, if the required action and associated completion time of Condition A is not met, be in Mode 3 within six hours and in Mode 5 within 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br />.

At the time of the teleconference on April 4, 2008, PNP was operating at approximately 100% power. On April 1, 2008, at approximately 1200 EDT, an auxiliary operator reported alarms for the safeguards transformer 1-1 and switchyard battery charger from the sub-station relay house.

Investigation led to obtaining oil samples from the safeguards transformer 1-1 main and load tap changer reservoirs. The oil sample results from the load tap changer reservoir were unsatisfactory, showing increased levels of combustible gases.

Safeguards transformer 1-1 was declared inoperable at 2155 EDT on April 1. TS 3.8.1 Condition A was entered for one offsite circuit inoperable.

ENO requested enforcement discretion for a period not to exceed 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> to complete repairs and post-maintenance testing of safeguards transformer 1-1. The approval of

Document Control Desk Page 2 the requested enforcement discretion was effective at 2155 EDT on April 4, 2008, and would expire at 2155 EDT on April 5, 2008.

This request was verbally transmitted to members of the NRC staff on April 4, 2008, at 1845 EDT. The NRC verbally granted the request on April 4, 2008, at 2050 EDT.

Subsequently, at 0100 EDT on April 5, 2008 the condition causing the need for this enforcement discretion was corrected resulting in exiting Required Action A.2 in TS 3.8.1 and the enforcement discretion.

Enclosure 1 provides the information documenting ENO's verbal request for enforcement discretion.

This information has been updated from the information discussed by ENO on April 4, 2008.

Additionally, the information addresses the issues identified by the NRC in the teleconference.

It provides the information specified in Nuclear Regulatory Commission (NRC) Regulatory Issue Summary 2005-01, "Changes to Notice of Enforcement Discretion (HOED) Process and Staff Guidance," dated February 7, 2005.

Summary of Commitments This letter contains one new commitment and no revisions to existing commitments.

Ensure risk management actions provided in section four of the enclosure are continued for the duration of this enforcement discretion.

Christopher J. Schwarz Site Vice President Palisades Nuclear Plant Enclosure CC Administrator, Region 111, USNRC Project Manager, Palisades, USNRC Resident Inspector, Palisades, USNRC

ENCLOSURE REQUEST FOR ENFORCEMENT DISCRETION 1.

TECHNICAL SPECIFICATION OR OTHER LICENSE CONDITIONS THAT WILL BE VIOLATED Palisades Nuclear Plant (PNP) Technical Specification (TS) 3.8.1, "AC Sources -

Operating," requires two qualified circuits between the offsite transmission network and the onsite Class 1 E AC electrical power distribution system to be operable in Modes 1, 2, 3, and 4. TS 3.8.1 Required Action A.2 requires, with one offsite circuit inoperable, restoring the offsite circuit to operable status within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />. TS 3.8.1 Required Actions F.1 and F.2 require that, if the required actions and completion times of Condition A are not met, be in Mode 3 within six hours and in Mode 5 within 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br />.

2.

CIRCUMSTANCES SURROUNDING THE SITUATION, INCLUDING LIKELY CAUSES, THE NEED FOR PROMPT ACTION, ACTION TAKEN IN AN ATTEMPT TO AVOID THE NEED FOR A NOTICE OF ENFORCEMENT DISCRETION (NOED), AND RELEVANT HISTORICAL EVENTS Circumstances Surrounding the Situation On April 1, 2008, at approximately 1200 EDT, an auxiliary operator was performing routine rounds and identified two alarms at the C-53 alarm panel in the switchyard relay house. The alarms were for the safeguards transformer 1-1 main reservoir sudden pressure relay and switchyard battery charger 1.

Investigation at the transformer found no indications (i.e., transformer isolation from 345KV and 2400V power sources, local alarm at the transformer, no oil loss, etc.) that a main tank sudden pressure relay actuation occurred.

However, the load tap changer tank pressure relief device semaphore flag was vertical, indicating a load tap changer pressure relief device actuation may have occurred.

This flag does not provide any actuation functions, but rather is an aid for observing that an actuation may have occurred. The pressure relief device operating pin indicated an actuation had not occurred. The initial investigation at the transformer found no indications that a load tap changer pressure relay device actuation occurred.

The system engineer recommended that the 2400 V buses be transferred from the safeguards transformer to the startup transformer to allow for further investigation of the observed conditions.

This also reduced the potential to damage the safeguards transformer if there was internal degradation. The load tap changer responded as expected when the buses were transferred and maintained voltage throughout.

An investigation was initiated to determine why the semaphore was in the actuated position, and why the safeguards transformer sudden pressure relay alarmed.

At 1459 EDT, the shift manager determined that safeguards transformer 1-1 was operable based on the visual inspection, a review of the voltage response when the buses were transferred, alarm indications, and having the mechanical signal semaphore in the actuated position without the associated automatic equipment response (indicating a spurious signal). The review concluded that there were no indications of transformer degradation.

One of the actions from the investigation was an analysis of oil in the safeguards transformer 1-1 main and load tap changer reservoirs.

Presence of combustion products in the oil would indicate degradation of internal components.

Oil analysis results were obtained at approximately 2130. The results indicated significant increases in concentrations of combustible gases for the load tap changer reservoir since the previous measurements in October 2004. The results for safeguards transformer 1-1 main oil reservoir were not significantly changed from previous satisfactory data. The sample results confirmed that there was internal degradation of the load tap changer. As a result, the shift manager declared safeguards transformer 1-1 inoperable at 2155 and entered TS 3.8.1, Condition A. Safeguards transformer 1 -1 was subsequently deenergized at 2311.

The presence of combustion gases in the load tap changer oil was caused by arcing in the load tap changer.

Electric Power Research Institute technical report 1002913, "Power Transformer Maintenance and Application Guide," Section 6.5.1.1 notes that hydrogen is produced from low intensity electrical discharges and acetylene from high intensity electrical discharges or electrical arcs that produce very high temperatures. The combustion gases found in the load tap changer oil included elevated levels of hydrogen and acetylene.

Likely Causes The root cause of the load tap changer degradation has not yet been determined.

On April 2, Entergy Nuclear Operations, Inc. (ENO) personnel disassembled and inspected the safeguards transformer 1-1 load tap changer. The inspection revealed that fasteners associated with the east phase of the internal interrupter assembly had become disengaged and were at the bottom of the load tap changer enclosure.

No degradation of the fasteners was noted except for one fastener bolt that had thread damage and possibly arc damage.

This condition caused the load tap changer interrupter assembly for this phase to become partially disconnected.

This resulted in arcing.

A review of previous work orders indicates that maintenance activity was performed on this load tap changer during the 2007 refueling outage. Workers had inspected the load tap changer, and removed and replaced the flexible strap leads (shunts) 2

on one phase of the interrupter assembly - the phase that was found disconnected on April 2.

The most likely cause for the loose fasteners was inadequate work practices during the 2007 refueling outage. These included:

Reusing the hex cone lock nuts These components are apparently intended for one-time use only. The Belleville washers were also reused.

However, these are not necessarily one-time use components.

Failing to use sealant The vendor manual does not directly call for the use of sealant to be used for sealing all lock nuts during installation.

In the ENO discussion April 4, 2008 it was indicated an assembly drawing of the load tap changer does specify for thread sealant to be used on this hardware.

Furthermore it was stated that review of the vendor manual determined that this requirement was included in a note on an attached print, and it may not have been apparent to the user.

Subsequent to the verbal request for enforcement discretion, it was determined that the assembly drawing note was misinterpreted and that the note does not address application of sealant on these particular fasteners.

Loctite 242 sealant was used on the threaded fasteners.

This application of Loctite 242 sealant has been reviewed and found acceptable.

Collectively, the combination of the above worker practices and the movement of the interrupter assembly during load tap changer tap changes caused the bolts to loosen, which eventually resulted in arcing across parts of the interrupter assembly.

Other work performed by the vendor that worked on safeguards transformer 1-1 was reviewed. The other work performed by the vendor was on the main transformer 1-1; station power transformers 1-1, 1-2, and 1-3; and motor operated disconnects MOD 26-H5 and MOD 24-F1.

No work was performed on the equipment that could affect availability of the remaining qualified offsite circuit.

ENO also investigated the indicated actuation of the sudden pressure condition in the main transformer.

Other indications including no automatic actuations, lack of alarm at the transformer and dissolved gas analysis results indicate an actual sudden pressure event had not occurred. The alarm was likely the result of an alarm card failure that also resulted in a DC ground. The alarm card was replaced.

Additionally, testing confirmed that the load tap changer pressure relief alarm and main reservoir sudden pressure alarm and protective circuitry are functioning correctly, and there is no interaction between the alarm circuits.

There is a 3

problem, however, with the control room alarm associated with main reservoir sudden pressure. This issue is currently being investigated.

This control room alarm is not required for operability of the off-site circuit and is unrelated to the problem experienced.

Need for Prompt Action The expected duration of the outage based on the current schedule will restore the transformer within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> of the required completion time for TS 3.8.1, Action A.2. Time is needed to obtain parts, which were available from only one identified source, to complete the repairs, and perform the post-maintenance testing.

If Operability of the safeguards transformer 1-1 cannot be restored by 2155 on April 4, 2008, PNP is required to shut down.

Action Taken in an Attempt to Avoid the Need for an NOED The transformer was declared inoperable on April 1, 2008, at 2155 EDT. ENO entered into augmented, around the clock staffing for multiple departments to establish and execute an expedited repair schedule. Work activities were initiated promptly to determine the cause of the problem, extent of condition, and required repairs.

In parallel, actions were taken to identify parts and other contingencies.

ENO is working with vendors to secure parts and to restore the transformer. The remaining work activities have been identified and scheduled. The PNP event response includes frequent alignment meetings to ensure the actions are progressing as planned and that additional support is provided when needed.

Management oversight ensures proper priorities are set and resources are provided. These actions ensure the transformer will be restored expeditiously.

Relevant Historical Events Safeguards transformer 1-1 was inspected during the 2007 refueling outage under work order 0026151. The work order required an inspection of the load tap changer.

During performance of that maintenance, the flexible shunts on the front side of the east phase interrupter assembly were replaced due to degradation caused by normal wear. Only the east phase required replacement. The front shunts on the other two phases were disconnected, inspected, and reconnected.

The rear shunts were inspected in place.

3.

INFORMATION TO SHOW THAT CAUSE AND PROPOSED PATH TO RESOLVE THE SITUATION ARE UNDERSTOOD, SUCH THAT THERE IS A HIGH LIKELIHOOD THAT PLANNED ACTIONS TO RESOLVE THE SITUATION CAN BE COMPLETED WITHIN THE PROPOSED NOED TIME FRAME The likely cause of worker practices was determined by a Kepner-Tregoe problem solving evaluation. ENO is confident that the cause is understood based on review 4

of associated work orders, discussion with maintenance personnel on expected worker practices, and a comprehensive review of vendor technical manual requirements. ENO reviewed photographs taken during the 2007 refueling outage and confirmed that all of the straps had been installed and the fasteners were in place. The likely cause is supported by physical evidence found during the recent inspection of the load tap changer enclosure.

The planned repairs to the transformer are expected to resolve the situation because the identified deficiencies will be corrected during the reinstallation.

Additional direction is provided in the work order.

Additional supervisory oversight of the reinstallation will provide greater assurance that the repairs are performed correctly. The schedule for repairs and subsequent post-maintenance testing was established based on previous experience with similar repairs. The replacement of the damaged components can be completed with normal work practices and parts.

The parts have arrived on site, and field work began after they were inspected. The interrupter device contains two sets of two shunts on each phase. The fasteners associated with the front set of shunts on all three phases were replaced.

Tightness checks were performed on the accessible rear set of connections that may have been disturbed during the 2007 refueling outage. No loose nuts were found.

However, the nuts associated with the front moving blades had as-found torque values of 10-15 foot pounds, whereas the as-found torque for the nuts on the corresponding front stationary arms were at 20 foot pounds.

This indicated a possible installation discrepancy and led to the decision to replace all the front load tap changer shunt bolting.

Sealant was applied to all shunt bolt threads to prevent loosening.

Based on the information above, the proposed NOED time frame of 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> provides sufficient time to complete the planned actions.

4.

SAFETY BASIS FOR THE REQUEST, INCLUDING AN EVALUATION OF THE SAFETY SIGNIFICANCE AND POTENTIAL CONSEQUENCES OF THE PROPOSED COURSE OF ACTION

a. Risk Assessment Using the Zero Maintenance Model ENO has evaluated the request for enforcement discretion from a probabilistic risk standpoint.

This assessment considered the expected plant configuration during the period of enforcement discretion and determined that it does not involve an unacceptable increase in risk. The risk of continued PNP operation with an inoperable offsite circuit during a three-day period of noncompliance beyond the TS 72-hour completion time, as measured by the incremental core damage probability (ICCDP) is 2.3E-08 for a plant internal event. This is below the guidance threshold of less than or equal to 5E-07 identified in NRC Inspection Manual Part 9900. The ICCDP for seismic, fire, and flood external events is bounded by the ICCDP for internal events, and, therefore, also meets 5

the guidance threshold. The results bound the proposed 24-hour period of noncompliance.

At PNP, core damage sequences involving a large, early release generally are those that bypass containment (i.e., those that involve steam generator tube rupture (SGTR) and intersystem loss-of-coolant accident initiating events).

Since the safeguards transformer unavailability only impacts the risk associated with loss of offsite power (LOOP) initiating events, and LOOP-initiated events generally do not lead to large, early releases, there was no significant change in the PNP large early release frequency (LERF) value. The incremental large early release probability (ICLERP) was determined to be 3E-10.

Note that the importance of selected SGTR sequences are elevated due to the conservative assumption applied to the conditional loss-of-offsite power sensitivity analysis involving internal events. The impact of these elevated sequences is included in the ICLERP calculation.

This is below the guidance threshold of less than or equal to 5E-08 identified in NRC Inspection Manual Part 9900.

b. Discussion of the Dominant Risk Contributors The top nine cutsets contributing to core damage for the internal events have not changed. These cutsets represent approximately 47% of the total increase in core damage probability. The top one hundred cutsets represent approximately 66% of the increase in core damage probability. The top one hundred cutsets are listed in the attached report.

Ninety out of one hundred listed cutsets did not change. The ten cutsets with increased contribution to core damage in the top one hundred cutsets are discussed below.

Cutset 10 - Loss of Offsite Power (Sequence 16)

This cutset represents a loss of offsite power, successful emergency diesel generator (EDG) start and load; however, due to common cause stressors, EDG 1-1, EDG 1-2 and EDG 1-3 fail to run for the considered mission time.

Successful auxiliary feedwater (AFW) (pump P-8B) operation occurs for four hours.

Nevertheless, failure is considered to occur within four hours (the PNP station blackout [SBO] design coping time duration) due to battery depletion.

Failure to recover AC power is assumed to lead to the inability to effectively control AFW and prevent steam generator (SG) overfill, which would fail the operating turbine-driven AFW pump.

Analysis margin:

Given four hours of successful AFW operation, this cutset would have in excess of ten hours for AC power recovery when considering decay heat removal for the four-hour period.

Moreover, emergency operating procedure (EOP) Supplement 19, revision 9 provides guidance to continue AFW operation assuming battery depletion. The present probabilistic risk analysis (PRA) model does not credit the ten-hour recovery period or the EOP supplement.

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Cuts et 16 - Controlled Shutdown (Seauence 20 This cutset represents a controlled shutdown event with a consequential loss of offsite power (LOOP 24 Hr Conditional Failure) subsequent to the event. The sequence includes common cause failure of all diesel generators to run, failure of the turbine-driven pump to run, and failure of once-through-cooling (OTC) (no AC power).

Analysis margin: The importance of this cutset is driven by the conservative assumption that increased conditional loss of offsite power (LOOP 24 Hr Conditional Failure) by a factor of ten.

Cutset 18

- Loss of Offsite Power (Seauence 43 This cutset represents a loss of offsite power, diesel generators failed to start or load, successful AFW (turbine driven pump) operation for four hours and failure to recover AC power within four hours (DC battery depletion).

Failure to recover AC power is assumed to lead to the inability to effectively control AFW and prevent SG overfill which would fail the operating turbine-driven AFW pump.

Analysis margin:

Given four hours of successful AFW operation, this cutset would have in excess of ten hours for AC power recovery when considering decay heat removal for the four-hour period.

Moreover, EOP Supplement 19, revision 9 provides guidance to continue AFW operation assuming battery depletion. The present PRA model does not credit the ten-hour recovery period of the EOP supplement.

Cutset 21

- Loss of Offsite Power (Seauence 8 This cutset represents a loss of offsite power, successful diesel generator operation, successful AFW operation for eight hours and failure to align makeup to the condensate storage tank after depletion or failure to initiate OTC or failure to align shutdown cooling.

Analysis margin: This cutset would have a recovery period of much greater than ten hours due to the successful operation of P-8B for approximately eight hours (condensate storage tank depletion).

Only the demineralized water storage tank (T-939) is currently credited with providing condensate storage tank makeup in the present PRA model.

Several other makeup sources are available but are not modeled.

Cutset 36 - Controlled Shutdown (Sequence 8)

This cutset represents a controlled shutdown event with a consequential loss of offsite power (LOOP 24 Hr Conditional Failure) subsequent to the event, 7

followed by successful AFW operation for eight hours (condensate storage tank depletion), failure to provide makeup to the condensate storage tank or an alternate suction source, failure to align SDC, and failure to successfully initiate OTC (operator action).

Analysis margin: This cutset would have a recovery period of much greater than ten hours due the successful operation of P-8B for approximately eight hours (condensate storage tank depletion). Only the demineralized water storage tank is currently credited with providing condensate storage tank makeup in the present PRA model.

Several other makeup sources are available which are not modeled.

Outset 48 - Loss of Offsite Power (Sequence 16)

This cutset represents a loss of offsite power, diesel generators started and loaded but failed to run (random failure of each diesel) for the mission time, successful AFW operation for four hours and failure to recover AC power within four hours (DC battery depletion).

Failure to recover AC power is assumed to lead to the inability to effectively control AFW and prevent SG overfill which would fail the operating AFW pump.

This cutset would have a ten-hour recovery period as a result of four hours of successful heat removal prior to failure.

Analysis margin:

Given four hours of successful AFW operation, this cutset would have a recovery period in excess of ten hours for AC power recovery when considering decay heat removal for the four-hour period.

Moreover, EOP Supplement 19, revision 9 provides guidance to continue AFW operation assuming battery depletion. The present PRA model does not credit the ten-hour recovery period of the EOP supplement.

Outset 56 IE

- CNTRLSD (Sequence 5) Controlled Shutdown This cutset represents a controlled shutdown event, with successful AFW operation for eight hours (depletion of the condensate storage tank), failure to makeup to the condensate storage tank, successful OTC followed by failure to remove heat from containment due to common cause failure of the traveling screens.

Analysis margin: This cutset would have a recovery period of much greater than ten hours due to the successful operation of P-8B for approximately eight hours (condensate storage tank depletion).

Only the demineralized water storage tank is currently credited with providing condensate storage tank makeup in the present PRA model.

Several other makeup sources are available but are not modeled.

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Outset 67 - Loss of Offsite Power (Sequence 5)

This cutset represents a loss of offsite power with subsequent recovery in thirty minutes (recovery in thirty minutes should be sequence 1, sequence 5 includes fail to recover in thirty minutes), the diesel generators started and loaded for the modeled mission time, successful AFW operation occurred for eight hours (until depletion of the condensate storage tank), failure to makeup to the condensate storage tank, successful operation of OTC but failure to remove heat from containment (failure of traveling screens (common cause failure of screens -

failure of service water) complete this cutset definition.

Analysis margin: This cutset would have a recovery period of much greater than ten hours due to the successful operation of P-8B for approximately eight hours (condensate storage tank depletion).

Only the demineralized water storage tank is currently credited with providing condensate storage tank makeup in the present PRA model.

Several other makeup sources are available which are not modeled.

Outset 77 Controlled Shutdown (Sequence 20)

This cutset represents a controlled shutdown event with a consequential loss of offsite power subsequent to the event (LOOP 24 Hr Conditional Failure ), failure of all diesel generators ( random failure of the diesels to run for the mission time),

failure of the turbine -driven pump to run, and failure of OTC (no AC power).

Analysis margin: The importance of this cutset is driven by the conservative assumption that increased conditional loss of offsite power (LOOP 24 Hr Conditional Failure) by a factor of ten.

Outset 78 Loss of Offsite Power (Sequence 33)

This cutset represents a loss of offsite power, successful diesel generators start and load but failed to run (common cause failure of all diesels) for the mission time, failure of the turbine-driven (P-8B) AFW pump and failure to recover AC power within two hours (with no AC power available and failure of P-8B two hours represents the window for successful alignment of OTC prior to core damage).

Analysis margin:

Given one hour of successful AFW operation during the initial EDG load and run period, this cutset would have in excess of five hours of additional AC power recovery time which is not currently credited in the model.

Regarding LERF, by itself, the change in core damage frequency (CDF) is sufficiently small to meet both the ICCDP and ICLERP criteria. That the change in LERF is even smaller is because removal of the safeguards transformer from service does not impact the containment dominant failure mode potential to 9

result in much of a change in the estimated LERF value.

Per the attached risk analysis, comparing Figures 7.2-1 and 7.2-2 the largest change in LERF can be attributed mostly to an increase in the transient sequences.

This change is driven by the conservative bounding value employed to address the conditional loss-of-offsite power sensitivity analysis. That is, the conditional likelihood of containment engineered safeguards equipment failing due to a transient initiator is due primarily to the assumed increase in the conditional failure-of-offsite power.

c. Discussion of the Compensatory Measures Implemented to Address the Dominant Risk Contributors In order to minimize risk during the period of noncompliance, ENO has identified additional controls to increase operator awareness of critical equipment, provide assurance that assumptions in the risk model are maintained, and minimize the likelihood of a plant transient. ENO proposes the following actions during the period of enforcement discretion to manage risk:

a)

No additional equipment associated with the AC power system will be removed from service or worked on for the duration of the safeguards transformer noncompliance.

This includes the remaining offsite circuit and the two diesel generators, each capable of supplying onsite Class 1 E power as described in the TS Bases 3.8.1.

b)

The remaining offsite circuit and diesel generators 1-1 and 1-2 will be protected with physical barriers and administrative controls (posting of protected train signage), preventing work on this equipment.

c)

Access will be limited to the following equipment important for maintaining the plant in a stable condition: 2400 Volt buses C, D, E; diesel generators 1-1 and 1-2, and supplemental diesel generator 1-3; main, station (1-1 and 1-2), and startup transformers; cable spreading room, and station batteries. Access is controlled by posted signs requiring approval by the operations shift manager prior to entry.

d)

No corrective maintenance, preventative maintenance, or surveillance testing will be performed on the remaining offsite circuit and the two diesel generators, or the attendant support equipment required by the TS definition of "Operable-Operability" except for surveillance requirement 3.8.1.1.

Palisades is in TS 3.8.1, condition A.

Required Action A.1 requires performance of surveillance requirement 3.8.1.1 (offsite source check) for the operable offsite circuit once per eight hours. ENO is not requesting enforcement discretion from this requirement.

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e)

The physical barriers referenced in item b above will be verified shiftly for the duration of the inoperability of the safeguards transformer and logged in the Operations log.

f)

No non-essential work will be allowed that could potentially jeopardize stable plant operation.

g)

No switchyard work or work on the main, station or startup transformers will be allowed.

h)

The plant operations crew will be briefed on these risk management measures.

i)

ENO will discuss with the grid operator the PNP condition and the need for heightened sensitivity and continual monitoring of grid conditions to anticipate challenges to offsite power availability.

j)

Operators will be briefed on sensitivity to safety bus electrical power supply issues to recognize and respond expeditiously to a station black out or loss of offsite power event.

k)

Operators will perform checks of the local switchyard house alarm panel twice a shift. Operators will notify the control room of any lit alarms, perform required actions in the alarm response procedure, and verify the procedure actions.

I)

A continuous fire watch will be implemented for startup transformer 1-3.

m)

If an equipment failure occurs that could affect the AC power function, the operations manager will be contacted to notify the NRC and convene an onsite safety review committee meeting to evaluate plant status, determine if the basis for the NRC's granting of the enforcement discretion is affected.

d. Demonstration of how the Proposed Compensatory Measures are Accounted for in the PRA No changes were made to the PRA model to account for compensatory measures and the potential to reduce the increased risk of the safeguards transformer removal from service. The benefit of the decision not to allow preventive maintenance, corrective maintenance or surveillance testing on any class 1 E equipment was removed from the model when the zero maintenance case was generated.

Possible changes to the model to account for the compensatory changes could have included:

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reduction of the probability of operator error for response to station blackout conditions, reduction of operator error probability in the implementation of OTC or shutdown cooling, reduction of operator error probability in response to AFW system failures (primarily pump P-8B),

removal of the fast transfer failures for failure to align the startup transformer, no credit for fire watch at startup transformer 1-2 to reduce the consequence of a potential fire in the transformer yard area, or no credit for backfeed via main transformer (not credited in the PRA model ) - many of the increased sequences have sufficient recovery time associated with them to allow alignment of the backfeed option.

12

Demonstration of how the Proposed Compensatory Measures are Accounted for in the PRA Outset Initiating Event Failures Applicable Compensatory Measures No.

10 Loss of Offsite EDG 1-1, 1-2 and 1-3 a) thru I).

For example compensatory Power IE common cause failure to run measure "j", the operators will be briefed on Failure to Recover (offsite the sensitivity to safety bus electrical power power) OSP in 30 min supply issues to recognize and respond Failure to Repair EDGs in expeditiously to a station black out or a loss 4 Hrs of offsite power event.

For example, Failure to Recover OSP in compensatory measure "c" addresses EDG 4 Hrs and vital switchgear common cause stressors by limiting access to the noted areas. Moreover, the listed compensatory measures address plant centered and switchyard centered LOOP events. The LOOP frequency was conservatively increased by a factor of two to address such potential challenges.

OSP recovery in 30 minutes and four hours is a measure of recovery of the external plant feeds. These actions are grid associated and not plant specific recove ry activities.

16 Controlled Manual P-8B failure to run a) thru I).

For example, compensatory Shutdown EE) measure "c" addresses EDG and vital EDG 1-1, 1-2 and 1-3 switchgear common cause stressors by common cause failure to run limiting access to the noted areas. The loss LOOP 24 Hr Conditional of offsite power conditional failure probability Failure was conservatively increased by a factor of ten to demonstrate the inherent margin in risk by applying bounding data. As noted in compensatory measure "j", the operators will be briefed on sensitivity to safety bus electrical power supply issues to recognize and respond expeditiously to a station black out or loss of offsite power event.

13

Cutset Initiating Event Failures Applicable Compensatory Measures No.

18 Loss of Offsite EDG 1-1, 1-2 and 1-3 a) thru I).

For example, as noted in Power (IE) common cause failure to start compensatory measure "j", the operators will Failure to Recover OSP in be briefed on sensitivity to safety bus 30 min electrical power supply issues to recognize Failure to Recover OSP in and respond expeditiously to a station black 4 Hr out or a loss of offsite power event.

Moreover, compensatory measure "c" addresses EDG and vital switchgear common cause stressors by limiting access to the noted areas.

OSP recovery in 30 minutes and four hours is a measure of recovery of the external plant feeds. These actions are grid associated and not plant s ecific recove ry activities.

14

Cutset Initiating Event Failures Applicable Compensatory Measures No.

21 Loss of Offsite Failure to Recover OSP in a) thru I).

For example, per compensatory Power (IE) 30 min measure "j" the operators will be briefed on Operator fails to align sensitivity to safety bus electrical power shutdown coolin g (SDC) supply issues to recognize and respond Operator fails to initiate OTC expeditiously to a station black out or loss of offsite power event.

For example, compensatory measure "c" addresses EDG and vital switchgear common cause stressors by limiting access to the noted areas.

OSP recovery in 30 minutes and four hours is a measure of recovery of the external plant feeds. These actions are grid associated and not plant specific recovery activities.

SDC and/or OTC alignment errors are considered risk insignificant given the time to recovery offsite power, the fact that the event response organization is manned 24/7 and if an event were to degrade to the condition that alternate strategies were mandated the emergency response organization will be manned per procedure. Given the heightened awareness it is considered that the organization, by procedure, is well prepared to address these hypothesized failures.

15

Cutset Initiating Event Failures Applicable Compensatory Measures No.

36 Controlled Manual Operator fails to align SDC DC and/or OTC alignment errors are Shutdown (IE)

Operator fails to initiate OTC considered risk insignificant given the time to LOOP 24 Hr Conditional recovery offsite power. The fact that the Failure event response organization is manned 24/7 and if an event were to degrade to the condition that alternate strategies were mandated the emergency response organization would be manned according to procedure.

a) thru I). The loss of offsite power conditional failure probability was conservatively increased by a factor of ten to demonstrate the inherent margin in risk by applying bounding data.

For example, as stated in compensatory measure "j", the operators will be briefed on sensitivity to safety bus electrical power supply issues to recognize and respond expeditiously to a station black out or loss of offsite power event.

48 Loss of Offsite Failure to Recover OSP in All a) thru I).

For example, per compensatory Power (IE) 30 min measure "j" the operators will be briefed on Failure to Recover OSP in sensitivity to safety bus electrical power 4 Hrs supply issues to recognize and respond Failure to Repair EDGs in expeditiously to a station black out or loss of 4 Hrs offsite power event.

EDG 1-1, EDG 1-2 and EDG 1-3 random failure to run OSP recovery in 30 minutes and four hours is a measure of recovery of the external plant feeds. These actions are grid associated and not plant specific recovery activities.

16

Cutset Initiating Event Failures Applicable Compensatory Measures No.

56 Controlled Manual Circuit breaker 152-302 This sequence represents a controlled Shutdown (IE) failure to open shutdown event, with successful AFW Traveling Screen common operation for eight hours. Considerable time cause Failure is available to recover from this event. The fact that the event response organization is manned 24/7 and if an event were to degrade to the conditions postulated in this sequence in which alternate strategies were mandated, the emergency response organization would be manned.

Therefore, given these hypothesized failures the organization is well trained to respond to random and common cause failures by p rocedure.

67 Loss of Offsite Failure to Recover OSP in a) thru I).

For example, the operators will be Power IE 30 min briefed on sensitivity to safety bus electrical Traveling Screen common power supply issues to recognize and cause Failure respond expeditiously to a station black out or loss of offsite power event. OSP recovery in 30 minutes is a measure of recovery of the external plant feeds. These actions are grid associated and not plant specific recovery activities.

17

Cutset Initiating Event Failures Applicable Compensatory Measures No.

77 Controlled Manual P-8B failure to run This sequence represents a controlled Shutdown IE shutdown event. Given the postulated EDG EDG 1-1, EDG 1-2 and EDG random failures, compensatory measure "j" is 1-3 random failure to run an example of the plants heightened LOOP 24 Hr Conditional awareness, given that the operators will be Failure briefed on sensitivity to safety bus electrical power supply issues to recognize and respond expeditiously to a station black out or loss of offsite power event.

The loss of offsite power conditional failure probability was conservatively increased by a factor of ten to demonstrate the inherent margin in risk by applying bounding data.

For example, as stated in compensatory measure "j", the operators will be briefed on sensitivity to safety bus electrical power supply issues to recognize and respond expeditiously to a station black out or loss of offsite power event.

78 Loss of Offsite P-8B failure to run a) thru I).

For example, per compensatory Power IE measure "j" the operators will be briefed on Failure to Recover OSP in sensitivity to safety bus electrical power 30 min supply issues to recognize and respond EDG 1-1, 1-2 and 1-3 expeditiously to a station black out or loss of common cause failure to run offsite power event.

For example, Failure to Repair EDGs in compensatory measure "c" addresses EDG 2 Hrs and vital switchgear common cause Failure to Recover OSP in stressors by limiting access to the noted 2 Hrs areas.

OSP recovery in 30 minutes and four hours is a measure of recovery of the external plant feeds. These actions are grid associated and not plant specific recove ry activities.

18

As noted above, regarding LERF, the largest change in LERF sequences can be attributed to the conservative bounding value employed to address the conditional loss-of-offsite power sensitivity analysis that results in a greater transient LERF contribution. The listed 4.c compensatory measures address the slight increase in ICLERP due to the assumed increase in the conditional loss-of-offsite power frequency.

e. Extent of Condition Sensitivity analyses were performed to assess the potential for an increase in the probability of failure of the of the startup transformer as a result of a potential common cause contributor.

The sensitivity analysis was completed by increasing the probability of failure of the startup transformer by two orders of magnitude. The results of the sensitivity analyses indicated that increasing the probability of failure of the startup transformer resulted in no significant change to the core damage frequency calculated for the zero maintenance case with the safeguards transformer out of service, increased probability of a consequential loss of offsite power, and an increase in the frequency for the loss of offsite power initiating event.

Therefore, the impact of a potential increase in the core damage frequency from common cause contribution for this condition is considered minimal.

f.

External Event Risk Fire The fire analysis completed for the independent plant evaluation external events (IPEEE) did not include an assessment of the impact of fire on transformers external to the plant.

Therefore, there was no risk significance associated with these transformers from fire events. NUREG 6850, Volume 2 (Reference 2.2.12 of attached risk analysis) includes a generic initiating event frequency of 1.2E-02 for

"`non-catastrophic" transformer yard fires that is based on fires at a particular transformer that does not propagate beyond the current location (transformer in question). The frequency could be subdivided among the transformers in the yard area. The resulting equivalent initiating event would be less than the loss of offsite power initiating event frequency for internal events (1.11 E-02).

Consequently, the core damage frequency for a fire at startup transformer 1-2 in conjunction with the unavailability of the safeguards transformer would constitute an equivalent loss of offsite power at a frequency lower than the current internal events loss of offsite power initiating event frequency.

Therefore, the contribution to core damage from a fire in this area is considered bounded by the internal events analysis.

The only identified impacts related to power from the transformers in the fire analysis completed for the IPEEE was the fire induced failure of the cables from the safeguards transformer and fire induced failures that would impact the fast transfer function in the east side and south end of the turbine building. As noted in the 19

report cables from the safeguards transformer were routed through these sections of the turbine building.

For this assessment the consequences of the fire impact to this cable routing would not matter given the transformer has been removed from service and fast transfer is not required since the plant is currently aligned to the startup transformer while the safeguards transformer is out of service. Also noted in the IPEEE report was the fact that the cables from startup transformer 1-2 are routed under ground from the transformer location to the bus 1 C switchgear room.

From their entry into the switchgear room the potential for fire induced failure of cables that could impact the availability of power from either transformer would have been considered a consequence of a fire in the area. The methodology employed in the IPEEE analysis was to consider all equipment/cables in the designated fire areas to be failed as a consequence of the fire with the exception of a small number of areas where suppression was available and the consequential component/cable failures were assessed in sequences where suppression failed.

Any component/cable failures that resulted from a postulated fire in a particular area that could result in a failure of offsite power via the safeguards or startup transformers would have been addressed in the assessment of each fire area.

There were no other instances identified in the IPEEE report where power was considered available from the safeguards transformer while power from startup transformer 1-2 was unavailable due to fire induced failure.

This condition would represent the circumstance where the unavailability of the safeguards transformer could result in a significant increase in the core damage frequency.

The plant has implemented compensatory measures to protect all electrical equipment associated with the 2400 V AC distribution system.

Seismic In the seismic analysis the loss of offsite power was analyzed by a single condition with a separate fragility. The fragility represented the potential for loss of offsite power based on the most limiting components subject to seismic failure. The most limiting component is the ceramic insulators. Because the ceramic insulators are much more likely to fail in a seismic event, the seismic contribution from combinations of component failures that could also result in a loss of offsite power were not analyzed. The seismic failure of the ceramic insulators is still considered the limiting failure of the remaining transformers.

Therefore, the removal of the safeguards transformer from service is not expected to result in any significant change to the existing core damage contribution from seismic events.

Flood The analyses completed for the IPE and IPEEE did not identify any risk significant contribution related to the safeguards or startup power transformers as a result of internal or external flooding.

20

Other The analyses completed for the individual plant evaluation (IPE) and IPEEE did not identify any risk significant contribution related to the safeguards or startup power transformers as a result of other external events.

g. Forecasted Weather Conditions Based on information obtained by operations there were no adverse weather conditions forecasted for the proposed period of the NOED.

Therefore, there were no plant vulnerabilities identified related to weather conditions.

Compensatory measures identified to protect electrical equipment during the period of the NOED are considered adequate based on the anticipated weather conditions.

Based on the risk analysis and the proposed compensatory measures ENO concludes there is no net increase in radiological risk to the public.

5.

JUSTIFICATION FOR THE DURATION OF THE NONCOMPLIANCE ENO requests that the NRC exercise discretion not to enforce compliance with TS 3.8.1, Required Actions F.1 and F.2, to allow for restoration of the safeguards transformer 1-1 to operable status. The duration of the noncompliance is limited to the time required to complete the necessary restoration activities. The restoration activities include:

Completing the restoration sequence to put back in service, which includes support from the switchyard contractor/owner.

Performing the post-maintenance test. This test requires changing the load tap changer with transformer unloaded and validating that voltage follows the load tap changer (functional test of the load tap changer).

Placing the load tap changer in automatic.

Loading the transformer, and validating proper voltage on all three phases.

Completing the operability review.

This duration also includes margin to accommodate expected variations in restoration.

For example, additional time may be required to perform the equipment alignments during restoration, complete test data evaluation, and confirm operability. The enforcement discretion would be in effect until safeguards transformer 1-1 is restored to operable status or the 24-hour noncompliance period ends, whichever occurs first.

21

Repair work has been completed.

Testing and restoration activities are currently in progress and are being worked on a 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> per day schedule.

6.

CONDITION AND OPERATIONS STATUS OF THE PLANT, INCLUDING SAFETY-RELATED EQUIPMENT THAT IS OUT OF SERVICE OR OTHERWISE INOPERABLE PNP is currently at 100% power.

Equipment out of service includes:

Safeguards transformer 1-1 Solenoid valves SV-1807 and SV-1808 position indication for purge isolation control valves Control valves CV-1910 and CV-1911 primary system flow sample isolation valves are caution tagged closed Secondary position indication for control rod drive 23 Pressurizer heater breaker 52-1601 Emergency lighting unit ELU-116 for component cooling water room The front bus is briefly deenergized to isolate the safeguards transformer for repairs as part of restoration activities The solenoid valves and control valves in the list above are safety-related. The other equipment is not safety-related.

The information presented in section four reflects the unavailability of the safeguards transformer 1-1 and front bus. The solenoid valves supply air to control valves that are in their closed fail safe position.

Because the above listed components (except the safeguards transformer and front bus) are not in the current risk model they were not evaluated in the analysis summarized in section four.

7.

STATUS AND POTENTIAL CHALLENGES TO OFF-SITE AND ON-SITE POWER SOURCES Diesel generators 1-1, 1-2 and 1-3 are operable and available to the safeguards buses and one qualified circuit between the offsite network and the onsite Class 1 E AC electrical power distribution system is operable.

Electrical system stability was verified by the following: The 345 kV bus voltages are normal and stable; system frequency is normal and stable; all 345 kV system line currents are normal; International Transmission Company, the transmission system owner, was contacted and they verified that the 345 kV system is stable with no known adverse system conditions expected to jeopardize the availability of the 345kV front or rear buses at PNP.

22

8.

BASIS FOR DETERMINING THAT THE NONCOMPLIANCE WILL NOT BE OF POTENTIAL DETRIMENT TO THE PUBLIC HEALTH AND SAFETY The proposed period of noncompliance will not be detrimental to public health and safety. ENO has evaluated the risk and determined it is sufficiently low. A summary of the evaluation is provided as part of item four, above. To further protect health and safety of the public, a number of risk management actions would be taken to increase operator awareness of critical equipment, to provide assurance that assumptions in the risk model are maintained, and to minimize the likelihood of a transient for the duration of the noncompliance.

9.

BASIS FOR CONCLUDING THAT THE NONCOMPLIANCE WILL NOT INVOLVE ADVERSE CONSEQUENCES TO THE ENVIRONMENT Although the proposed action involves noncompliance with a requirement of the TS, 1.

There is no significant change in the types or significant increase in the amounts of any effluent that may be released offsite. The proposed action does not affect the generation of any radioactive effluent, nor does it affect any of the permitted release paths; and 2.

There is no significant increase in individual or cumulative occupational radiation exposure. The proposed action would not significantly affect plant radiation levels, and, therefore, would not significantly affect dose rates and occupational exposure; and 3.

There are no significant nonradiological environmental consequences.

Therefore, ENO has concluded that the proposed action will not involve adverse consequences to the environment.

10. ONSITE SAFETY COMMITTEE REVIEW COMMITTEE REVIEW APPROVAL This request was approved by the onsite safety review committee.

11. WHICH NOED CRITERION FOR APPROPRIATE PLANT CONDITIONS IS SATISFIED AND HOW IT IS SATISFIED ENO has evaluated the requested enforcement discretion against the criteria specified in section B of NRC Inspection Manual, Part 9900:

"Operations - Notices of Enforcement Discretion [NOED]," issued February 7, 2005.

This section states, "for an operating plant, the NOED is intended to (a) avoid unnecessary transients 23

as a result of compliance with the license condition and, thus, minimize the potential safety consequences and operational risks, or (b) avoid testing, inspection, or system realignment that is inappropriate for the particular plant conditions."

The NOED criteria in section 2. 1.1(a) for an operating plant are satisfied. PNP is operating at approximately 100% power. Compliance with TS 3. 8.1 would initiate an unnecessary transient by requiring the plant to initiate a shutdown on April 4, 2008. The proposed action would allow continued plant operation to perform the required repair and testing.

Granting the NOED will preclude the operational risk associated with a transient during the shutdown. No corresponding health and safety benefit is gained by requiring a plant shutdown. Based on the above, the criteria are satisfied.

12. FOLLOW-UP LICENSE AMENDMENT A permanent amendment is not an appropriate resolution because it would rely on complex compensatory actions that are not practical on a permanent basis. The proposed compensatory actions would prohibit work on any additional equipment associated with the AC power system, prohibit maintenance and surveillance testing on AC power equipment and support equipment, require protecting both trains of several components, and severely limit the scope of work that could be performed. A permanent change would also preclude performing other required TS surveillances. As such, a permanent amendment is not practical or appropriate.

13. SEVERE WEATHER OR OTHER NATURAL PHENOMENA The proposed enforcement discretion does not involve severe weather or other natural events.

14. OTHER INFORMATION Participants discussed oil sampling and the plant licensing basis during the verbal request for enforcement discretion. The following information is provided to address reviewer questions.

Oil Sampling The oil sampling program is being reviewed. An accelerated sampling frequency would be provided for the Safeguards Transformer 1-1.

Plans are for the samples to be taken from the load tap changer chamber and the transformer chamber with the exception that the load tap changer chamber is at a vacuum under some temperature conditions.

Sampling of the load tap changer chamber may need to 24

be deferred based on these conditions. ENO plans to sample twice weekly for two weeks, once per week for four weeks, and then once per month for five months.

Station Blackout PNP is not a self-induced Station Blackout plant.

25

ATTACHMENT TO REQUEST FOR ENFORCEMENT DISCRETION EVALUATION OF SAFEGUARDS TRANSFORMER EX-07 ANOMALIES ASSOCIATED WITH AN OIL PRESSURE RELAY ACTUATION (72 pages follow)

LT R-PSA-08-01 April 7, 2008 Rev 1 To: Bob VanWagner

Subject:

Evaluation of S ards XFMR (EX 07) Anomalies Associated with an Oil Pressure Relay Actuati Prepar rank and Brianrogan Reviewed By: Dave Blanchard, AREI (See Attachment C)

INTRODUCTION/OBJECTIVE The purpose of this assessment is to evaluate the safety significance of extending the Safeguards Transformer Allowed Outage Time (AOT). As noted in the Palisades Technical Specifications (TS) limiting condition for operation (LCO) for EX-07 is 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />.

The objective of the PRA analysis is to provide the safety basis for an NOED request, which includes an evaluation of the safety significance and potential consequences of the proposed course of action. The results from this evaluation are an input to an NOED which is prepared by the site's Regulatory Affairs department.

Rev 1 Changes:

1 Several editing changes were made to Section 6.4 2

Cutset 56 added to Section 6.4 3 Table A-2 added to Attachment A 4

Table A-1 editorial changes made 5

Table B-3 added to Attachment B Pg 1 of 21

LT R-PSA-08-01 April 7, 2008 Rev 1 TABLE OF CONTENTS

1.0 BACKGROUND

1.1 CONDITION REPORT (CR-PLP-2008-01500)

1.2 INTRODUCTION

/OBJECTIVE 2.0 ANALYSIS INPUT/REFERENCES 2.1 INPUT

2.2 REFERENCES

3.0 DEFINITIONS/ACRONUMNS 4.0 ASSUMPTIONS 4.1 MAJOR ASSUMPTIONS 4.2 MINOR ASSUMPTIONS 5.0 METHODOLOGY 6.0 ANALYSIS 6.1 VALIDATION OF THE CURRENT MODEL OF RECORD (PSAR2c) 6.2 MAINTENANCE CONDITION 6.3 LOSS OF OFFSITE POWER, PLANT AND SWITCHYARD CENTERED MAINTENANCE CONSIDERATIONS 6.4 INTERNAL EVENT CUTSET REVIEW 6.5 LARGE EARLY RELEASE FREQUENCY (LERF) 7.0 RESULTS 7.1 INTERNAL EVENT INCREMENTAL CONDITION CORE DAMAGE PROBABILITY (ICCDP) 7.2 INTERNAL EVENT INCREMENTAL CONDITION LARGE EARLY RELEASE PROBABILITY (ICLERP) 7.3 EXTERNAL EVENTS - SEISMIC 7.4 EXTERNAL EVENTS - FIRE 7.5 EXTERNAL EVENTS - FLOODING AND OTHER 7.6 SPURIOUS ACTUATION OF THE DELUGE SYSTEM FOR THE STARTUP TRANSFORMER

8.0 CONCLUSION

S Attachment A - SAPHIRE CDF Change Set Data and Results Attachment B - SAPHIRE LERF Change Set Data and Results Attachment C - AREI Review of Tech Letter PSA-08-01 3

3 3

3 3

4 5

6 6

8 9

9 9

9 10 11 13 14 14 15 18 19 20 20 21 Pg2of21

LTR-PSA-08-01 April 7, 2008 Rev 1

1.0 BACKGROUND

1.1 CONDITION REPORT (CR-PLP-2008-01500)

At 1220 hours0.0141 days <br />0.339 hours <br />0.00202 weeks <br />4.6421e-4 months <br /> on 01 April, 2008 (all times local) the Outside AO reported alarm tile EK-5036 "Safeguards XFMR 1-1 Sudden Pressure Relay in solid out in the Sub-Station Relay House. A subsequent walk down of Safeguards XFMR (EX-07) revealed that although there was no evidence of oil leakage, fire, or any other anomalies associated with a sudden pressure relay actuation, the Load Tap Changer Oil Tank Mechanical semaphore (a yellow flag associated with the relief device) was actuated (aligned in the vertical position). The Electrical System Engineer called out to aid in diagnostics recommended removal of loads from EX-07. Operators then briefed & transferred 2400 vac Buses 1 C, 1 D, and 1 E from EX-07 (Front Bus) to EX-04 (Rear Bus). These transfers were made at 1254, 1258, and 1303, respectively. These actions are consistent with those listed in ARP-13 (EK-5036) and ARP-37 (EK-5044).

Subsequent removal of the front bus from service to electrically isolate EX-07 for oil sampling and other diagnostics if necessary was performed. Subsequent trouble-shooting commenced.

1.2 INTRODUCTION

/OBJECTIVE Safeguards Transformer No 1-1 (EX-07) was installed as Phase II of the Offsite Power Reliability Improvement Project (Refout'90) and it serves as the normal source of power to the 2400 volt buses for all modes of plant operation.

The purpose of this assessment is to evaluate the safety significance of extending the Safeguards Transformer Allowed Outage Time (AOT). As noted in the Palisades Technical Specifications (TS) limiting condition for operation (LCO) for EX-07 is 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />.

The objective of this PRA analysis is to provide the safety basis for an NOED request, which includes an evaluation of the safety significance and potential consequences of the proposed course of action. The results from this evaluation are an input to an NOED which is prepared by the site's Regulatory Affairs department.

2.0 ANALYSIS INPUT/REFERENCES 2.1 INPUT 2.1.1 SAPHIRE Codes - executables (*.exe files) can be found in the "J:\\Engineering\\Eng_prgm\\Rel_Eng\\PSA\\SAPHIRE" folder on the Palisades intranet.

Table 2.1-1 lists the file specifics.

Table 2.1.1 (Reference 2.2.5)

Filename Date Time Size SAPHIRE-7-26-866621894.exe 10/24/2005 3:45p 14.079 KB 2.1.2 Table 2.1.2 below lists the baseline CAFTA files.

This baseline CAFTA model (Reference 2.2.1) serves as the starting point of the core damage fault tree model update documented in this analysis.

Table 2.1.2 Filename Description Date Time Size - KB PSAR2c. be PSAR2c CAFTA Basic Event File 6/26/2006 1 : 42p 1,248 PSAR2c. caf PSAR2c CAFTA Fault Tree File 6/26/2006 136p 449 Pg3of21

LTR-PSA-08-01 April 7, 2008 Rev 1 Fil PSAR2c.gt PSAR2c.tc Table 2.1.2 cription Date Time Size - KB A Gate Type File 6/24/2006 1:31p 1,024 A Type Code File T5/27/2004 9:03a 30 A Files.zip PSAR2c CAFTA zip file 6/29/2006 8:47a 289 PSAR2c 2.1.3 Table 2.1.3 lists the PSAR2c SAPHIRE project file (Reference 2.2.1) used as the initial data set for this analysis.

Caf2Sap PSAR2c.txt caf2sap.exe Creation of Rules File F PSAR2c FTree Logic.ftl 3/24/2003 Table 2.1.3 Time 8:59a^

8:16a 2:42p 9:16a 11 Text rules file used by caf2sap.exe to create MAR-D files.

28 Visual basic application for creating SAPHIRE MAR-D fault tree files.

2,162 EXCEL spreadsheet that creates tt

'.txt rules file for SAPHIRE MAR-D fault tree assembly.

3,421 MAR-D fault tree file created from the PSAR2c CAFTA master fault tree.

SAPHIRE v7.26 PSAR2c Ftree 6/29/2006 9:43a _

1,099 Above listed supporting files.

Files.zip 2.1.4 Table 2.1.4 defines the House Event configuration used in this evaluation:

Table 2.1.4 House Event House Event A HSE-CST-MAKEUP F

! I-HSE-M2LEFT-INS T

C-HSE-P-52A-STBY T I-HSE-M2RGHT-INS -- F C-HSE-P-52 B-STBY T M-HSE-P-2A-TR IP T^

C-HSE-P-52C-STBY FM-H SE-P-2B-TRIP F

1,D-H SE-CHGR1-INS T M-HSE-SJAEI-I NS

'T D-HSE-CHGR2-INS T;M-HSE-SJAE2-INS F

D-HSE-CHGR3-INS F U-HSE-P-7A-STBY T

D-H SE-CHG R4-INS F U-HSE -P-7B-STBY F

HE SE-AI R-GT-75F T U-HSE-P-7C-STBY 7F E-HSE AIR-LT-75F F X-HSE-2SG-BLDN 1

E-HSE-BYPASS-REG T X-HSE-2SG-BLDN-A 1J E-HSE-EDG11-DEM T X-HSE -2SG-BLDN-B 1

E-HSE -EDG1 I -RUN T

X-HSE-SGA-BLDN 1

E-H SE-EDG12-DEM T X-HSE-SGB-BL DN 1

E-HSE-EDG12-RUN T Y-HSE-LOOPIA-BR K T

-HSE-C -2AC-INS T 'Y-HSE-LOOP1B-BRK F'

I-HSE-C-2B-INS F Y-HSE-LOOP2A-BRK F

-HSE-F-12A-INS T Y-HSE-LOOP2 B-BRK F

-HSE-F-12B-INS F Y-HSE-RAS-POST F

.I-HSE-F-5A-INS T Y-HSE-RAS-PRE F

l-HSE-F-56-INS F X-HSE-DOOR-1676 I T X-HSE-DOOR-167 T

2.2 REFERENCES

2.2.1 EA-PSA-PSAR2c-06-10 r0, "Update of Palisades CDF Model - PSAR2b to PSAR2c".

2.2.2 EA-PSA-SAPHIRE-05-16 r0, "SAPHIRE v7.26 Validation and Verification".

2.2.3 SAPHIRE REFERENCE MANUAL, "SYSTEMS ANALYSIS PROGRAMS FOR HANDS ON INTEGRATED RELIABILITY EVALUATIONS (SAPHIRE) VERSION 6.0", Idaho National Engineering Laboratory, 1998.

Date 6/29/2006 Pg4of21

LTR-PSA-08-01 April 7, 2008 Rev 1 2.2.4 SAPHIRE TECHNICAL REFERENCE, "Systems Analysis Program for Hands-on Integrated Reliability Evaluations (SAPHIRE) Version 6.0", Idaho National Engineering Laboratory, 1998.

2.2.5 EA-PSA-SAPHIRE-05-16 r0, "SAPHIRE v7.26 Validation and Verification". NUREGICR-2300 volume 1, "PRA Procedures Guide".

2.2.6 NUREG-0492, "Fault Tree Handbook", 1981.

2.2.7 EA-PSA-CET-R1-04-21r0, "Conversion of IPE CET Models from CAFTA to SAPHIRE".

2.2.8 Nuclear Regulatory Commission (NRC) Inspection Manual, Part 9900: Technical Guidance, "Operations - Notices of Enforcement Discretion", February 7, 2005.

2.2.9 "PWROG Review of Selected Loss of Offsite Power PRA Topics", WCAP-16778-NP, May 2007, Revision 0, Draft.

2.2.10 NUREG/CR-6890 (INL-EXT-05-00501), Volume 1, Reevaluation of Station Blackout Risk at Nuclear Power Plants, December 2005 (USNRC).

2.2.11 EA-PSA-LOOP-04-23, "Palisades Owners Review of KFlemings "Independent Review and Reanalysis of Loss of Offsite Initiating Event Frequency for Palisades Nuclear Plant" Final Report rv 2".

2.2.12 NUREG/CR-6850 (EPRI 1011989), "EPRIINRC-RES Fire PRA Methodology for Nuclear Power Facilities, Volume2:

Detailed Methodology".

2.2.13 Design Basis Document (DBD)-3.01, "External Power Supply Transformers", revision 5, 2/20/2007.

2.2.14 Design Basis Document (DBD-7.08), "Plant Protection against Flooding", revision 5, 12/15/2004.

2.2.15 EA-PSA-PSAR2-04-02 r0, "Update of Palisades CDF Model - PSAR1 B Modified w/HELB to PSAR2".

2.2.16 CPCo to NRC Letter, January 29, 1993, Palisades Plant Individual Plant Examination for Severe Accident Vulnerabilities (IPE), [F341/1523].

2.2.17 CPCo Letter to NRC, dated 6/30/95, Response to Generic Letter 88-20, Supplement 4, Individual Plant Examination of External Events for Severe Accident Vulnerabilities (IPEEE), Final Report (G326/2290).

2.2.18 Palisades Letter for Submittal of the Revised Fire Analysis, dated May 31, 1996 (G700/0629).

2.2.19 EA-PSA-LERF-99-0020, "Re-Creation of Palisades IPE LERF Model".

2.2.20 Applicant's Environmental Report - Operating License Renewal Stage Palisades Nuclear Plant Nuclear Management Company, Docket No. 50-255, License No. DPR-20, March 2005.

3.0 DEFINITIONS /ACRONYMNS 3.1 AOT-allowed outage time as defined in the Technical Specifications.

3.2 CCDP - conditional core damage probability, the core damage probability for a given plant initiating event for all potential accident initiating events in the PSA.

3.3 containment bridge tree (CBT) - containment system event tree that includes containment system fault trees such as containment air coolers, sprays, etc. The end states of the containment bridge tree describe the state of various containment functions from the availability of sprays to the status of different PCS injection systems.

3.4 containment event tree (CET) - the non-system challenges or phenomenological threats to the containment are characterized in the containment event tree logic. This logic represents various issues from steam explosions to direct containment heating and the likelihood of such events challenging the containment structurally integrity. The plant damage state frequencies are input to the CET's.

3.5 CDF - core damage frequency, the calculated probability of a core damage event for any given year for all potential accident initiating events in the PSA.

3.6 CDP - core damage probability, the core damage probability for a specified time (i.e., 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> or 3 months) for all potential accident initiating events in the PSA, equal to the CDF times the specified length of time.

3.7 CLERP - conditional large early release probability, the large early release probability for Pg5of21

LTR-PSA-08-01 April 7, 2008 Rev 1 a given plant initiating event for all potential accident initiating events in the PSA.

3.8 LERF - large early release frequency, the calculated probability of a significant radiological release to the public prior to completing emergency plan evacuation procedures following a core damage event for any given year for all potential accident initiating events in the PSA.

3.9 LERP - large early release probability, the large early release probability for a specified time (i.e., 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> or 3 months) for all potential accident initiating events in the PSA, equal to the LERF times the specified length of time.

3.10 Level t (1) - PSA studies that deterministically evaluate internal events and only core damage.

3.11 Level /t (2) - PSA studies that deterministically evaluate internal events and core damage as well as the containment response that includes the probability of containment failure.

3.12 model

- an approximate mathematical representation that simulates the behavior of a process, item, or concept (such as failure rate).

For example, the probability of a system is synthesized using models that relate system failures to component failures and human errors.

3.13 Notice of Enforcement Discretion (NOED) - Is a document issued by Nuclear Regulatory Commission (NRC) to exercise enforcement discretion with regard to limiting condition for operation (LCO) in power reactor Technical Specifications (TS) or other license conditions.

3.14 plant damage state - it is not practical to perform detailed analysis of each core damage sequence. Therefore, the core damage sequences are grouped into bins that pose similar containment system challenges and result in like fission product releases. These product or bins are referred to as plant damage states. The plant damage state frequencies are input to the containment event tree.

3.15 probabilistic risk assessment (PRA) or probabilistic safety analysis (PSA) - a quantitative assessment of the risk associated with plant operation and maintenance. Risk is measured in terms of the frequency of occurrence of different events, including core damage. In general the scope of a PRA is divided into three categories: Level 1, 2, and 3.

A Level 1 maps from initiating events to plant damage states (PDSs), including their aggregate, core damage. Level 2 includes Level 1 mapping from initiating events to release categories. Level 3 includes Level 2 and uses the release categories of Level 2 to quantify consequences, the most common of which are health effects and property damage in terms of cost. Full scope PRA includes internal and external events.

3.16 Safety Basis - Information typically provided by PRA personnel to justify that a requested NOED has no significant increase in radiological risk to the public.

3.17 truncation limits

- the cutoff value of probability or frequency of individual accident sequences below which they are no longer retained in quantitative PRA model results. A truncation value is primarily used for the purpose of managing the size of the analysis results.

4.0 ASSUMPTIONS 4.1 MAJOR ASSUMPTIONS 4.1.1 The plant is assumed to be in either mode's 1, 2 or 3 as the initial condition prior to an event.

4.1.2 Use the zero maintenance PRA model to establish the plant's baseline risk and the estimated risk increase associated with the period of enforcement discretion (Reference 2.2.8).

For the plant-specific configuration the plant intends to operate in during the period of enforcement discretion, the incremental conditional core damage probability (ICCDP) and incremental conditional large early release probability (ICLERP) will be quantified and compared with guidance thresholds of less than or equal to an ICCDP of 5E-7 and an ICLERP of 5E-8. These numerical guidance values are not pass-fail criteria.

Pg6of21

LTR-PSA-08-01 April 7, 2008 Rev 1 4.1.3 Plant Centered Maintenance Considerations The potential impact of the plant-centered contribution to the loss of offsite power initiating event frequency was assessed by increasing the loss of offsite power initiating event frequency by a factor of 2 for an updated value of 2.22E-021yr.

This value is considered conservative.

Basis:

NUREG/CR-6890 (Reference 2.2.10), Distributions for the Industry LOOP Frequencies Table 4.1.3 Prior Frequency Distribution LOOP Category Mean Frequency (per critical year)

Plant Centered 2.07E-03 Switchyard Centered 1.04E-02 Grid Related East Central Area Reliability Coordination Agreement (SCAR) 3,33E-02 Weather 4.83E-03 Total 5.06E-02 21 (1)

With the exception of Grid Related Events, are obtained from Table 3-3 of NUREG/CR-6890. The value or Grid Related events use the mean frequency from Table 3-6 NUREG/CR-6890.

(2)

As noted in Reference 2.2.11, using data which had been screened for applicability to Palisades (e.g.,

hurricanes, plant specific design differences) resulted in a LOOP value of 1.11 E-02/yr.

From Table 4.1.3 the Plant Centered events contribute less than 5% to the total LOOP (Loss of Offsite Power) frequency and Switchyard Centered events contribute less than 21 % to the total LOOP frequency.

Given that a failure of EX-07 would be classified as a Plant Centered event, increasing the LOOP frequency by a factor of 2 is conservative.

PWROG Review of Selected Loss of Offsite Power PRA Topics (Reference 2.2.9)

To understand LOOP duration and recovery likelihood, Reference 2.2.9 parsed LOOP frequency into plant centered, weather related, and grid centered events. LOOP duration is a strong function of the assigned category. The following figure illustrates that plant centered events power recovery are characteristically different from the other two categories.

Plant centered events tend to allow for alternate connections to the grid as only one component (e.g., transformer, bus duct) contributed to the loss of connection to at least one offsite power source while other means remain available to restore a path to an offsite source.

Note for Palisades, backfeed via the main and station power transformers remains available and is not credited in the PRA.

Grid and weather events were found to last longer. A grid event requires restarting the network over a relatively wide geographic area. Weather events involve reconstruction of the physical grid followed by restarting the network.

Pg7of21

LTR-PSA-08-01 April 7, 2008 Rev 1

.200 I.000 0.800 0.600 0.400 0.200 0.000

-0.200 Hours In summary, the Reference 2.2.9 results point to a distinction between plant, weather, and grid events in the maximum duration estimates. Weather events take about 50%

longer to recover from compared to grid events. The plant centered event durations are the most uncertain of the groups.

It should be noted that given the data sources, the specific estimates for a plant-centered LOOP duration are the most researched by the industry while the other types (weather and grid) are more difficult to pin down.

In conclusion, industry data shows that plant centered maintenance events are very likely to be recovered within less than ten hours of the experienced failure.

Therefore if other concurrent failures were experienced while EX-07 is out of service, the recovery period would be short.

4.2 MINOR ASSUMPTIONS 4.2.1 The Level 1 analysis applied a 1 E-10 truncation limit. The Level II analysis applied a 1 E-09 truncation limit.

The 1 E-10 CDF truncation limit is conservative as 1 E-09 is normally used. The Palisades Level II analysis is a detailed assessment of containment performance.

It is considerably more rigorous than the Owners Group simplified LERF methodology.

Consequently to solve some 60,000 plant damage state sequences, a truncation limit of 1 E-09 is employed.

This is considered appropriate given the detail in the Palisades plant damage state and containment event tree models.

Moreover, the plant damage states are not subsumed resulting in a conservative aggregated result.

Basis: The Palisades Level II sequences analysis results (methods described in References 2.2.7, 2.2.15, 2.2.16, 2.2.19 and 2.2.20) do not subsume the correlated containment bridge tree sequences to the assigned sequence endstates. This is because the interface between the Level 1 and the Level 2 analyses is controlled by the Plant Damage State (PDS) Containment Bridge Tree (CBT).

The core damage event tree sequences are binned according to the available six distinct containment safeguard system states. The result of combining the internal event initiators to the six containment safeguard categories results in some 181 plant damage states. The 181 endstates are then mapped to 23 containment event trees. Given the unique identification of these bins, Boolean subsuming cannot occur. The outcome is a Pg8of21

LTR-PSA-08-01 April 7, 2008 Rev 1 5.0 6.0 6.1 conservative answer as the resultant release categories are overestimated on the order of 20 to 40%, typically.

METHODOLOGY The methods employed to address the impact of extending Safeguards Transformer (EX-

07) are described and include the SAPHIRE software and users manual (References 2.2.3 and 2.2.4) as well as the Nuclear Regulatory Commission (NRC) Inspection Manual, Part 9900 (Reference 2.2.8).

ANALYSIS This section describes the specific analysis performed to analyze the safety significance and potential consequences of extending the EX-07 LCO period.

VALIDATION OF THE CURRENT MODEL OF RECORD (PSAR2C)

The baseline results for the current model of record are; Baseline results with current system alignment (at 1 E-09 truncation):

CDF

1. Cutsets Sequence 2.611E-05 (non subsumed) 2362 End State Gather 2.489E-05 (subsumed) 1708 6.2 Validation of the model was completed by quantification with nominal maintenance unavailabilities to confirm that the stated results were duplicated. The results were correctly replicated.

MAINTENANCE CONDITION The NOED guidance (Reference 2.2.8) requires the assessment to be performed based on a zero maintenance condition (all values assigned for the probability of equipment being removed from service set to 0). This condition is established by using the existing SAPHIRE change set (MAINT_UNVAIL(0)) which resets the indicated probabilities to zero (Attachment A).

In order to assure adequate representation of the transformer out-of-service condition this calculation and the remaining risk calculations were conducted with a truncation value of 1.0E-10.

Baseline results with Maintenance Probabilities reset to zero:

CDF

1. Outsets Sequence 2.656E-05 (non subsumed) 8361 End State Gather 2.521 E-05 (subsumed) 7239 The model includes a change set file for the configuration of equipment assumed to be in-service or standby at the time of an event. The assumed conditions represent an arbitrary choice of system/train alignments expected to be in place for the normal at-power condition. None of the alignments made with this SAPHIRE change set impact the assessment of the transformer out-of-service configuration. Therefore the change is used as-is for this assessment (Input 2.1.4).

The model includes the safeguards transformer as the primary source of power to the 2400vac buses (bus 1 C, 1 D, and 1 E).

Startup transformer 1-2 is included as the secondary supply to the 2400vac buses. Alignment of the startup transformer is via fast transfer.

If the fast transfer fails or the transformer is otherwise unavailable, the Pg9of21

LTR-PSA-08-01 April 7, 2008 Rev 1 emergency diesel generators will automatically start and align to the respective 2400vac bus (EDG 1-1 to bus 1 C and EDG 1-2 to Bus 1 D). Power to bus 1 E will be unavailable unless manually aligned by an operator when the diesel generators are supplying power.

Failure of fast transfer is not an issue with the transformer aligned as the source of power to the 2400vac buses.

Failure of fast transfer was not removed from the model and remains as a minor conservative contribution to the failure of the startup transformer.

The analysis does not include an operator action to manually align the startup transformer 1-2 if fast transfer fails. An operator action is included for alignment of power to bus 1 E. The model does not include credit for `backfeed' to the 2400vac buses via the main and station power transformers. This initial assessment of risk was developed by assigning the basic event for the safeguards transformer fails to function to TRUE. As a result, all power from the safeguards bus to the three 2400vac buses (1 C, 1 D and 1 E) is unavailable (lost).

The zero maintenance case was re-quantified with the safeguards transformer (EX-07) out-of-service. The results of this case (OSG-Case3) are shown in the following table.

Zero maintenance conditions with the safeguards transformer OOS:

CDF

1. Cutsets Sequence 2.711E-05 (non subsumed) 13843 End State Gather 2.575E-05 (subsumed) 9484 6.3 LOSS OF OFFSITE POWER, PLANT AND SWITCHYARD CENTERED MAINTENANCE CONSIDERATIONS The current PRA model includes two related conditions which could be impacted by the unavailability of the safeguards transformer. The first condition is the loss of offsite power initiating event frequency. The most recent data update of applicable generic data with plant specific operating experience resulted in an initiating event frequency of 1.11 E-02/yr. While there is no direct correlation in the data analysis between the loss of offsite power initiating event frequency and the availability of the safeguards transformer, the unavailability of the transformer potentially impacts the portion of the initiating event frequency attributed to plant-centered events. A review of the industry data indicates that plant-centered events contribute approximately 5% of the total loss of offsite power frequency.

If the unavailability of the safeguards transformer represented an order of magnitude increase in the contribution to the frequency of a loss of offsite power from plant-centered events, then the increased loss of offsite power frequency could be 1.61 E-02.

11 E-02

• 0.05 *10 = 5.55E-03 11 E-02 *0.95 + 5.55E-03 = 1.61 E-02 The potential impact of the plant-centered contribution to the loss of offsite power initiating event frequency was assessed by increasing the loss of offsite power initiating event frequency by a factor of 2 (Assumption 4.1.3) for an updated value of 2.22E-02/yr.

The second event is the consequential loss of offsite power.

For all other initiating events (other than loss of offsite power) the model includes a basic event (P-LOOP-24HR) which represents the probability that offsite power could be lost as a consequence of the initiating event. The event probability is based on industry data where offsite power was lost as a consequence of or subsequent to the initiating event. As with the loss of offsite power initiating event frequency it is possible that the consequential loss of offsite power probability may also be increased by the unavailability of the safeguards transformer.

Pg10of21

LTR-PSA-08-01 April 7, 2008 Rev 1 Again, there is currently no direct correlation in the derivation of the failure rate used for the consequential loss of offsite power with the availability of specific components that constitute the means of accomplishing the function.

If the unavailability of the safeguards transformer represented an order of magnitude increase in the rate of a consequential loss of offsite power, that would result in a corresponding increase in the probability of the consequential failure.

Note that the consequential failure is considered possible at any time during the 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> mission time with the same consequence in the last hour of the mission time as in the first hour. The increase in time available for recovery and number of options available after each successful hour of mitigation were not considered.

The potential impact of the unavailability of the safeguards transformer on the probability of a consequential loss of offsite power was considered by increasing the probability by an order of magnitude (from 4.48E-04 to 4.48E-03) for this assessment.

6.4 INTERNAL EVENT OUTSET REVIEW A review of the change to the cutsets contributing to core damage as a result of the changes made to represent the removal of the safeguards transformer form service are discussed below.

The top 9 cutsets contributing to core damage for the internal events increase have not changed. These cutsets represent - 47% of the total increased core damage probability.

The top 100 cutsets represent - 66% of the increased core damage probability. Ten cutsets showing an increased contribution to core damage are described below. The top 100 cutsets are listed in Attachment A.

Ninety out of one hundred of the listed cutsets did not change.

Outset 10 Loss of Offsite Power (Sequence 16)

This cutset represents a loss of offsite power, successful diesel generator start and load; however, due to common cause stressors, EDG 1-1, EDG 1-2 and EDG 1-3 fail XfailX to run for the considered mission time, successful AFW (P-8B) operation occurs for 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />; nevertheless, failure is considered to occur within 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> (Palisades Station Black Out (SBO) design coping time duration) due to battery depletion.

Failure to recover ac power is assumed to lead to the inability to effectively control AFW and prevent SG overfill which would fail the operating turbine-driven AFW pump.

Analysis margin:

Given 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> of successful AFW operation this cutset would have in excess of 10 hours1.157407e-4 days <br />0.00278 hours <br />1.653439e-5 weeks <br />3.805e-6 months <br /> of ac power recovery when considering decay heat removal for the 4 hour4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> period (Reference 2.2.1).

Moreover, EOP-9 Supplement 19 revision 9 has been updated to provide guidance to continue AFW operation assuming battery depletion. The present PRA model does not credit the 10 hour1.157407e-4 days <br />0.00278 hours <br />1.653439e-5 weeks <br />3.805e-6 months <br /> recovery period or the EOP-9 recent supplement revision.

Outset 16 Controlled Shutdown (Sequence 20)

This cutset represents a controlled shutdown event with a consequential loss of offsite power subsequent to the event. The sequence includes common cause failure of all diesel generators to run, failure of the turbine-driven pump to run, and failure of Once-Through-Cooling (no ac power).

Analysis margin: The importance of this cutset is driven by the conservative assumption that increased conditional loss of offsite power by a factor of 10.

Pg 11 of 21

LTR-PSA-08-01 April 7, 2008 Rev 1 Outset 18 Loss of Offsite Power (Sequence 43)

This cutset represents a loss of offsite power, diesel generators failed to start or load, successful AFW (turbine driven pump) operation for 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> and failure to recover ac power within 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> (dc battery depletion).

Failure to recover ac power is assumed to lead to the inability to effectively control AFW and prevent SG overfill which would fail the operating turbine-driven AFW pump.

Analysis margin: Given 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> of successful AFW operation this cutset would have in excess of 10 hours1.157407e-4 days <br />0.00278 hours <br />1.653439e-5 weeks <br />3.805e-6 months <br /> of ac power recovery when considering decay heat removal for the 4 hour4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> period.

Moreover, EOP-9 Supplement 19, revision 9 has been updated to provide guidance to continue AFW operation assuming battery depletion. The present PRA model does not credit the 10 hour1.157407e-4 days <br />0.00278 hours <br />1.653439e-5 weeks <br />3.805e-6 months <br /> recovery period or the EOP-9 recent revision.

Outset 21 Loss of Offsite Power (Sequence 8)

This cutset represents a loss of offsite power, successful diesel generator operation, successful AFW operation for 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> and failure to align makeup to the condensate storage tank (T-2) after depletion or failure to initiate Once-Through-Cooling (OTC) or failure to align shutdown cooling.

Analysis margin: This cutset would have a much greater than a 10 hour1.157407e-4 days <br />0.00278 hours <br />1.653439e-5 weeks <br />3.805e-6 months <br /> recovery period due the successful operation of P-8B for -8 hours (T-2 depletion).

Only T-939 is currently credited with providing T-2 makeup in the present PRA model.

Several other makeup sources are available which are not modeled.

Outset 36 Controlled Shutdown (Sequence 8)

This cutset represents a controlled shutdown event with successful AFW operation for 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> (condensate tank depletion), failure to provide makeup to the condensate storage tank or an alternate suction source and failure to successfully initiate Once-Through-Cooling (operator action).

Analysis margin:

This cutset would have a much greater than a 10 hour1.157407e-4 days <br />0.00278 hours <br />1.653439e-5 weeks <br />3.805e-6 months <br /> recovery period due the successful operation of P-8B for --8 hours (T-2 depletion).

Only T-939 (Demin Water Storage Tank) is currently credited with providing T-2 makeup in the present PRA model.

Several other makeup sources are available which are not modeled.

Outset 48 Loss of Offsite Power (Sequence 16)

This cutset represents a loss of offsite power, diesel generators started and loaded but failed to run (random failure of each diesel) for the mission time, successful AFW operation for 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> and failure to recover ac power within 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> (dc battery depletion).

Failure to recover ac power is assumed to lead to the inability to effectively control AFW and prevent SG overfill which would fail the operating AFW pump.

This cutset would have a 10 hour1.157407e-4 days <br />0.00278 hours <br />1.653439e-5 weeks <br />3.805e-6 months <br /> recovery period as a result of four hours of successful heat removal prior to failure.

Analysis margin: Given 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> of successful AFW operation this cutset would have in excess of 10 hours1.157407e-4 days <br />0.00278 hours <br />1.653439e-5 weeks <br />3.805e-6 months <br /> of ac power recovery when considering decay heat removal for the 4 hour4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> period.

Moreover, EOP-9 Supplement 19, revision 9 has been updated to provide guidance to continue AFW operation assuming battery depletion. The present PRA model does not credit the 10 hour1.157407e-4 days <br />0.00278 hours <br />1.653439e-5 weeks <br />3.805e-6 months <br /> recovery period or the EOP-9 recent supplement revision.

Pg12of21

LT R-PSA-08-01 April 7, 2008 Rev 1 Outset 56 IE_CNTRLSD (Sequence 5)

This cutset represents a controlled shutdown event, with successful AFW operation for 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> (depletion of the condensate storage tank (T-2)), failure to makeup to the condensate storage tank, successful OTC followed by failure to remove heat from containment due to common cause failure of the traveling screens.

Analysis margin:

This cutset would have a much greater than a 10 hour1.157407e-4 days <br />0.00278 hours <br />1.653439e-5 weeks <br />3.805e-6 months <br /> recovery period due the successful operation of P-8B for -8 hours (T-2 depletion). Only T-939 is currently credited with providing T-2 makeup in the present PRA model.

Several other makeup sources are available which are not modeled.

Outset 67 Loss of Offsite Power (Sequence 5)

This cutset represents a loss of offsite power with subsequent recovery in 30 minutes (recovery in 30 minutes should be sequence 1, sequence 5 includes fail to recover in 30 minutes), the diesel generators started and loaded for the modeled mission time, successful AFW operation occurred for 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> (until depletion of the condensate storage tank (T-2)), failure to makeup to the condensate storage tank, successful operation of OTC but failure to remove heat from containment (failure of traveling screens (common cause failure of screens - failure of service water) complete this cutset definition.

Analysis margin:

This cutset would have a much greater than a 10 hour1.157407e-4 days <br />0.00278 hours <br />1.653439e-5 weeks <br />3.805e-6 months <br /> recovery period due the successful operation of P-8B for -8 hours (T-2 depletion). Only T-939 is currently credited with providing T-2 makeup in the present PRA model.

Several other makeup sources are available which are not modeled.

Outset 77 Controlled Shutdown (Sequence 20)

This cutset represents a controlled shutdown event with a consequential loss of offsite power subsequent to the event, failure of all diesel generators (random failure of the diesels to run for the mission time ), failure of the turbine -driven pump to run, and failure of OTC ( no ac power).

Analysis margin : The importance of this cutset is driven by the conservative assumption that increased conditional loss of offsite power by a factor of 10.

Outset 78 Loss of Offsite Power (Sequence 33)

This cutset represents a loss of offsite power, successful diesel generators start and load but failed to run (common cause failure of all diesels) for the mission time, failure of the turbine-driven pump (P-813) AFW pump and failure to recover ac power within 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> (with no ac power available and failure of P-8B 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> represents the window for successful alignment of Once-Through-Cooling prior to core damage).

Analysis margin:

Given 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> of successful AFW operation during the initial EDG load and run period, this cutset would have in excess of 5 hours5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br /> of additional ac power recovery time which is not currently credited in the model.

6.5 LARGE EARLY RELEASE FREQUENCY (LERF)

The Palisades Level II assessment included re-evaluating the containment plant damage states assuming no maintenance unavailability, similar to core damage evaluation above.

Next, the zero maintenance case was quantified with the safeguards transformer (EX-07) out-of-service AND the probability of the basic event representing a consequential loss of Pg13of21

LTR-PSA-08-01 April 7, 2008 Rev 1 offsite power (P-LOOP-24HR) increased by a factor of 10 AND the initiating event frequency for a loss of offsite power event increased by a factor of 2. The resulting set of endstate frequencies were mapped to 23 containment event trees (CET). The CETs represent the non-system challenges or phenomenological threats to the containment.

This logic represents various issues from steam explosions to direct containment heating and the likelihood of such events challenging the containment. The outputs of the CETs are mapped to endstates that characterize the timing of the release (Timing Bins) and the magnitude (Release Magnitude Bins).

Timing Bins Three timing classifications are used, as follows:

1.

Early (E) - less than 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> from accident initiation 2.

Intermediate (I) - greater than or equal to 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />, but less than 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> 3.

Late (L) - greater than or equal to 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.

The definition of the categories is based upon past experience with offsite responses:

0-4 hours is based on a Palisades plant specific analysis discussed in the following section.

4-24 hours is a time frame in which most of the offsite nuclear plant protective measures can be accomplished.

>24 hours are times at which the offsite measures can be assumed to be fully effective.

Release Magnitude Bins The four severity classifications associated with volatile or particulate releases are defined as follows:

High (H) - A radionuclide release of sufficient magnitude to cause near-term health effects.

Moderate (M) - A radionuclide release with the potential for latent health effects.

Low (L) - A radionuclide release with the potential for minor health effects.

Low-Low (LL) - A radionuclide release that is less than or equal to the containment design base leakage resulting in no health effects.

A LERF release category equates to a Palisades CET E-H release category.

7.0 RESULTS This section reports the quantitative and qualitative results.

7.1 INTERNAL EVENT INCREMENTAL CONDITIONAL CORE DAMAGE PROBABILITY (ICCDP)

The zero maintenance case was quantified with the safeguards transformer (EX-07) out-of-service AND the probability of the basic event representing a consequential loss of offsite power (P-LOOP-24HR) increased by a factor of 10 AND the initiating event frequency for a loss of offsite power event increased by a factor of 2 (OSG Case 5)(refer Pg 14 of 21

LTR-PSA-08-01 April 7, 2008 Rev 1 to Attachment A for the SAPHIRE change set information). The results of the quantification under these conditions are shown in the following table.

Results with safeguards transformer (EX-07) out of service and impacts to consequential LOOP and initiating event frequency considered are shown below:

CDF

1. Outsets Sequence 2.943E-05 (non subsumed) 14809 End State Gather 2.804E-05 (subsumed) 9684 7.2 Removing the safeguards transformer from service and considering impacts to consequential LOOP and initiating event frequency results in an increase in CDF of 2.83E-06/yr or 3.23E-10/hr.

(2.804E 2.521 E-05)

(2.83E-06/yr/(365days/yr*24hrs/day))

The current allowed outage time (72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />) represents a Core Damage Probability (CDP) of 2.33E-08 for 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />.

3.23E-1 0/hr*3days*24hrs/day The CDP associated with an extension of the current allowed outage time is 4.65E-08 for 6 days (144 hours0.00167 days <br />0.04 hours <br />2.380952e-4 weeks <br />5.4792e-5 months <br />).

3.23E-1 0/hr*6days*24hrs/day This results in an Incremental Conditional Core Damage Probability (ICCDP) of 2.32E-08 (4.65E 2.33E-08) for the extension to a 6 day period.

The original analysis did not include the Front Bus out-of-service in addition to the safeguards transformer. This does not make any difference in the core damage quantification. A sensitivity analysis was completed with the front bus assumed unavailable in combination with the conditions stated in the preceding section. The results of the sensitivity analysis produced the same result as reported above - no change in core damage frequency based on the addition of the front bus out-of-service.

INTERNAL EVENTS INCREMENTAL CONDITIONAL LARGE EARLY RELEASE PROBABILITY (ICLERP)

As was the case above, for the core damage analysis, the zero maintenance case was first evaluated by quantifying the plant damage states and then mapping the results to the 23 CETs yielding the following zero maintenance release frequencies (Figure 7.2-1, below presents the event contribution to the E-H (LEFF) release frequency.

Plant Damage State E-H (LERF)

E-M I-H I-M L-L L-LL ry lyr

/yr

/yr

/yr j

/yr

/yr Summa 2.813E-07 6.086E-06 14.427E-06 18.165E-06 4

4.623E-0 7 9.887E-06 2.931E-05'"

(1) Overstated by about 17% due to employing non-subsumed results. Therefore the calculated release frequencies are conservatively overestimated by about 17%.

Figure 7.2-1, below presents the event contribution to the E-H (LERF) release frequency category. The figure represents over 90% of the sequence contribution to the E-H (LERF).

Pg15of21

LTR-PSA-08-01 April 7, 2008 Rev 1 Figure 7.2-1:

PSAR2c Zero Maintenance (Initiating Event Contribution to LERF)

Medium Large LOCA,

ATWS, Small Break LOCA, 17.9%

Transient, 0.3%

ISLOCA, 31.9%

Attachment B provides the SAPHIRE Change Sets for both the plant damage state analysis and the CET evaluation.

Also the top 25 CET sequences and cutsets are listed in "Table B-1: PSAR2c Zero Maintenance, E-H (LERF) Only".

And similarly, the zero maintenance case was quantified with the safeguards transformer (EX-07) out-of-service AND the probability of the basic event representing a consequential loss of offsite power (P-LOOP-24HR) increased by a factor of 10 AND the initiating event frequency for a loss of offsite power event increased by a factor of 2.

Again, the results of the 181 plant damage bins were mapped to the 23 CETs resulting in the following set of release frequencies:

E-H (LERF)

E-M I-H I-M L-L L-LL Plant Damage State

/yr

/yr

/yr

/yr

/yr

/yr Summary

/yr 3.145E-07 6.178E-06 4.370E-06 1.066E-05 1.501E-06 1.147E-05 3.450E-05")

(1) overstated by about 23% due to employing non-subsumed results.

Therefore the calculated release frequencies are conservatively overestimated by about 23%.

Figure 7.2-2, below presents the initiating event contribution to the E-H (LERF) release frequency category. The figure represents over 90% of the sequence contribution to E-H (LERF).

Pg16of21

LTR-PSA-08-01 April 7, 2008 Rev 1 Figure 7.2-2:

PSAR2c Zero Maintenance, EX-07 Failed, LOOP and Conditional LOOP Probabilities Increased ( Initiating Event Contribution to LERF)

Medium Large COCA, ATWS, 21 Small Break COCA, 14.6%

Transient, 10.8%

Attachment B provides the SAPHIRE Change Sets for both the plant damage state analysis and the CET evaluation.

Also the top 25 CET sequences and cutsets are listed in "Table B-2: PSAR2c Zero Maintenance, EX-07 Failed, LOOP and Conditional LOOP Probabilities Changed, E-H (LERF) Only".

Removing the safeguards transformer from service and considering impacts to consequential LOOP and initiating event frequency results in an increase in LERF of 3.32E-081yr or 3.79E-12/hr.

(3.145E 2.813E-07)

(3.32 E-08/yr/(365days/yr*24hrs/day))

The current allowed outage time (72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />) represents a Core Damage Probability (LERP) of 2.73E-10 for 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />.

3.79E-1 2/hr*3days*24hrs/day The LERP associated with an extension of the current allowed outage time is 5.458E-10 for 6 days (144 hours0.00167 days <br />0.04 hours <br />2.380952e-4 weeks <br />5.4792e-5 months <br />).

3.79E-1 2/hr*6days*24hrs/day This results in an Incremental Conditional Large Early Release Probability (ICLERP) of 2.73E-10 (5.458E 2.73E-10) for the extension to a 6 day period.

Regarding LERF, by itself, the change in CDF is sufficiently small to meet both the ICCDP and ICLERP criteria. That the change in LERF is even smaller is because removal of the safeguards transformer from service does not impact the containment dominant failure mode potential to result in much of a change in the estimated LERF value.

Comparing Figures 7.2-1 and 7.2-2 the largest change in LERF can be attributed mostly to an increase in the transient sequences (Table B-3 shows this as well).

This change is driven by the conservative bounding value employed to address the conditional Pg17of21

'-ISLOCA, 28.0%

LTR-PSA-08-01 April 7, 2008 Rev 1 loss-of-offsite power sensitivity analysis. That is, the conditional likelihood of containment engineered safeguards equipment failing due to a transient initiator is due primarily to the assumed increase in the conditional failure-of-offsite power.

7.3 EXTERNAL EVENTS - SEISMIC In the Palisades IPEEE (Individual Plant Examination of External Events) (References 2.2.17 and 2.2.18) the potential for seismic failures of station power, startup power and safeguards power transformers and their impact on the availability of offsite power was not specifically assessed. A fragility for LOOP (Loss of Offsite Power) was calculated based on the most limiting component that causes this event. The most limiting component is the ceramic insulators. The fragility for off-site power also incorporates the possible affects of the fire protection system on the main transformers, should actuation occur. The main transformers deluge system contains a low seismic capacity check valve that may cause a loss of off-site power by actuating the deluge system during a seismic event.

The component random failures rates that were used in the IPE (Individual Plant Examination of Internal Events) (Reference 2.2.16) were also used in the SPRA (Seismic Probabilistic Risk Assessment). No adjustments to these probabilities were made. The seismic impact on these components was assessed by including seismic basic events and fragilities.

The component fragilities that were identified in Section 3.5.2 of the IPEEE reports were used in the SPRA. The fragilities were input as a median capacity with a lognormal standard deviation (beta), which defined a lognormal fragility curve.

In addition to the seismic basic events, the seismic fault trees were modified to include seismically induced initiating events. The four seismic event tree headings that are seismically induced initiating events are: TBFR (Turbine Building Fire); TBFL (Turbine Building Flood); LOOP (Loss of Offsite Power); and SBL (Small Break Loss of Coolant Accident).

All events that are affected by a turbine building fire have an associated basic event of TBFR.

All basic events that are affected by a turbine building flood have an associated basic event of TBFL. The affected off-site power related equipment received an associated basic event of LOOP. The initiating event SBLOCA (Small Break Loss of Coolant Accident) was given to all sequences that were quantified by the SBLOCA event tree and was not included in the fault tree as a basic event.

Since the seismic risk assessment was based on the fragility of the limiting components that would result in a loss of offsite power, the current condition with a transformer out of service and one remaining in service (with respect to class 1 E 2400vac power) would be considered bounded by the IPEEE results since the failure of the in service transformer would be determined by the fragility of the insulators.

Also as noted in the IPEEE report, should a seismic event lead to a loss of off-site power, diesel generator operation becomes important.

Diesel generator 1-2 (EDG 1-2) was determined to have a higher importance relative to diesel generator 1-1 (EDG 1-1) as it supplies power to auxiliary feedwater (AFW) pump P-8C. This AFW pump is important to long term makeup to the steam generators should the fire system become unavailable following a seismic event (as discussed in the results for Accident Classes IA & IB, Section 3.6.5.3.1 of the IPEEE report). The fire protection system has a low fragility and is a significant contributor to seismic risk once the contents of the condensate storage tank (T-2) are depleted and a long term suction source is required for continued operation of the AFW pumps. The seismically induced failure of the fire protection system represents a higher probability of failure of the long term suction to motor-driven auxiliary feedwater pump P-8A and turbine-driven auxiliary feedwater pump P-8B after the Pg 18 of 21

LTR-PSA-08-01 April 7, 2008 Rev 1 depletion of the available tank T-2 inventory.

This increased probability of failure of the A and B pumps results in an increased importance of motor-driven AFW pump P-8C.

The importance of pump P-8C is a consequence of the fact that service water (a much more seismically rugged system) is more likely to remain available as a long term suction source to pump P-8C. The increased importance of diesel generator 1-2 (EDG 1-2) is similarly based on it being the source of power to pump P-8C.

The contribution to core damage from seismic events determined in the IPEEE was 8.88E-06.

This represents approximately 13% of the total core damage frequency from the current internal events analysis (2.49E-05), fire (3.3.1 E-05), flooding (-<2E-07) and seismic (8.88E-06). Therefore the expected seismic contribution is bounded by the internal events core damage assessment described in this letter.

7.4 EXTERNAL EVENTS - FIRE The fire analysis completed for the IPEEE did not include an assessment of the impact of fire on transformers external to the plant. Therefore there was no risk significance associated with these transformers from fire events. NUREG 6850, Volume 2 (Reference 2.2.12) includes a generic initiating event frequency of 1.2E-02 for `non-catastrophic' transformer yard fires that is based on fires at a particular transformer that does not propagate beyond the current location (transformer in question).

This frequency can be subdivided among the total population of transformers. The frequency could be subdivided among the transformers in the yard area. The resulting equivalent initiating event would be less than the loss of offsite power initiating event frequency for internal events (1.11 E-02).

Consequently, the core damage frequency for a fire at startup transformer 1-2 in conjunction with the unavailability of the safeguards transformer would constitute an equivalent loss of offsite power at a frequency lower than the current internal events loss of offsite power initiating event frequency.

Therefore the contribution to core damage from a fire in this area is considered bounded by the internal events analysis.

The only identified impacts related to power from the transformers in the fire analysis completed for the IPEEE was the fire induced failure of the cables from the safeguards transformer and fire induced failures that would impact the fast transfer function in the east side and south end of the turbine building. As noted in the report cables from the safeguards transformer were routed through these sections of the turbine building.

For this assessment the consequences of the fire impact to this cable routing would not matter given the transformer has been removed from service and fast transfer is not required since the plant is currently aligned to the startup transformer while the safeguards transformer is out of service. Also noted in the IPEEE report was the fact that the cables from startup transformer 1-2 are routed under ground from the transformer location to the bus 1 C switchgear room.

From their entry into the switchgear room the potential for fire induced failure of cables that could impact the availability of power from either transformer would have been considered a consequence of a fire in the area. The methodology employed in the IPEEE analysis was to consider all equipment/cables in the designated fire areas to be failed as a consequence of the fire with the exception of a small number of areas where suppression was available and the consequential component/cable failures were assessed in sequences where suppression failed. Any component/cable failures that resulted from a postulated fire in a particular area that could result in a failure of offsite power via the safeguards or startup transformers would have been addressed in the assessment of each fire area. There were no other instances identified in the IPEEE report where power was considered available from the safeguards transformer while power from startup transformer 1-2 was unavailable due to fire induced failure. This condition would represent the circumstance where the unavailability of the safeguards transformer could result in a significant increase in the core damage frequency.

Pg19of21

LTR-PSA-08-01 April 7, 2008 Rev 1 7.5 EXTERNAL EVENTS - FLOODING AND OTHER The analyses completed for the IPE and IPEEE did not identify any risk significant contribution related to the safeguards or startup power transformers as a result of internal or external flooding or any of the other external events evaluated.

In addition, the plant design basis document (DBD-3.01 External Power Supply Transformers, revision 5) indicates in section 3.4.4.3 that no flooding issues had been identified related to the power supply transformers (which include the safeguards and startup transformers).

Also design basis document 7.08 (DBD-7.08) Plant Protection Against Flooding (revision 5) did not identify any consequential failures related to the power transformers from flooding.

Specifically table 9-2 (EVALUATION OF EQUIPMENT POSTULATED TO BE SUBMERGED BY INTERNAL FLOODING) did not include any components related to the power transformers.

7.6 SPURIOUS ACTUATION OF THE DELUGE SYSTEM FOR THE STARTUP TRANSFORMER As documented in CR-PLP-2008-01220, the deluge system for EX-05 "Startup Transformer 1-3" actuated with no fire or hot-spots present on the transformer. A standing alarm was present due to a damaged portion of the transformer's line type fire detection wire, henceforth referred to as "Protectowire." Due to the standing deluge actuation signal, fire protection water for all three startup transformers (EX-03, EX-04, and EX-05) had been isolated and fire watch tours added. To support restoration of the deluge system, Engineering Change 6652 processed a temporary modification to install a new partial run of Protectowire and eliminate the standing deluge signal.

Troubleshooting had shown that the fault on the installed Protectowire is an intermittent fault. The deluge system was restored on March 28, 2008.

EX-05 is located outside in the yard area which is not designated as an Appendix R Fire Area and is not discussed in the Palisades Plant Fire Hazards Analysis Report revision 7.

Startup Transformer EX-05 has two elevations of fire protection nozzle piping, one at 597' and the other at 605'. Secured to the fire protection piping is one continuous length of Protectowire circling the transformer at both elevations.

Upon an alarm signal from the Protectowire, the control panel opens deluge valve CK-FP408 which sprays all three startup transformers with fire water.

Electrical safety restrictions would not allow repair of the 605' section of Protectowire due to the proximity to 345kV power sources at the top of the transformer.

In order to restore full fire protection to EX-03 and EX-04, and to restore one elevation of fire detection to EX-05, a new length of Protectowire was installed around the 597' nozzle piping.

Functionally, the new length of Protectowire will perform identically to the currently installed Protectowire.

If a fire is detected, the wire will send an alarm condition to EC-1003 and the startup transformers will be deluged. The area of detection for EX-05 is the only change was made by the temporary modification.

Instead of having detection at both the 597' and 605' elevations, only 597' detection will be available.

Due to the high intensity heat and pressure produced by a transformer fire/explosion, a real event would still be detected by the transformer's sudden pressure relay and should be detected by the Protectowire (even at the lower elevation).

Both methods of detection will actuate startup transformer deluge.

Installing a new length of Protectowire at the 597' transformer elevation provided more fire protection to EX-05 than the degraded configuration and allowed complete fire protection to be restored to EX-03 and EX-04.

As previously stated, EX-05 is not included on the Appendix R Safe Shutdown Equipment List and the transformer will remain protected by a deluge system as indicated in the BTP 9.5-1 Appendix A response however with reduced fire detection capability.

Pg20of21

LTR-PSA-08-01 April 7, 2008 Rev 1 Compensatory fire tours will remain to augment the reduced fire detection capability.

This condition will remain until plant conditions will allow the transformer to be de-energized and the Protectowire restored to the full design configuration.

Given action has been taken to eliminate the postulated cause of the problem (intermittent fault on the installed Protectowire), the potential for spurious actuation of the deluge system with startup transformer 1-2 in service is considered to be restored to its original state and the likelihood of a spurious actuation during this period of time would be low.

8.0 CONCLUSION

S The internal events core damage analysis conservatively calculated an Incremental Conditional Core Damage Probability (ICCDP) of 2.32E-08 (4.65E 2.33E-08) for the Safeguards extension to a 6 day period. The internal events analysis is considered bounding for the evaluated external events including fire, flood and seismic.

Moreover, the calculated ICLERP was conservatively estimated to be 2.73E-10 (5.458E 2.73E-10).

Therefore extending the present LCO duration for anther 3 days results in a change in risk that is less than the prescribed limit in the Nuclear Regulatory Commission (NRC)

Inspection Manual, Part 9900 of will be quantified and compared with guidance thresholds of less an ICCDP of 5E-7 and an ICLERP of 5E-8.

Pg 21 of 21

LTR-PSA-08-01 April 4, 2008 Attachment A SAPHIRE CDF Change Set Data and Results Table of Contents SAPHIRE Zero Maintenance Unavailabilities A-2 Change Set SAPHIRE w/Safeguards Transformer Failed A-3 Change Set Table A-1: PSAR2c Zero Maintenance, EX-07 A-4 Failed, LOOP and Conditional LOOP Probabilities Changed (Top 100 Cutsets)

Table A-2: Top Ten Cutsets with Noun Failure A-17 Descriptors A-1

LT R-PSA-08-01 April 4, 2008 Attachment A SAPHIRE CDF Change Set Data and Results SAPHIRE Zero Maintenance Unavailabilities Change Set PROBABILITY HEADER Name CaltcTyp e, Unc'Type,

Prob, Lambda,

Tau, UncValue,

UncCorr, MlssionT,

Flag, UncValue2 CLASS HEADER

Name, Group,

CompType, Compld,

System, Location,

Failiode, Train,

mnit, AttI,,Att16 CLASS PROBABILITY HEADE R

CalcType, UncType, Pro b,

Lambda, Tau,

LrcValue, UncCorr,

Mission, Flag, UncValue2

PSAR2C, N_AINT 3NAVAIL(O)

'PROBABILITY A-PNOO-P-8A

.000E+000, A-PMOO-P-8B v.000E+000, A-PMCO-P-8C 0.000E+000, C-PMOO-P-52A 1,

0.000E+000, C-PMOO-P-52B 0.000E-000, C-PMOO-P-52C 11, 0.000E+000, D-BC00-ED-15 0.000E+000, D-BC00-ED-16 1,

0.000E+000, D-BC00-ED-17 1,

0.000E+000, D-BCOO-ED-18 1,

0.000E+000, E-DGOO-K-6A 1,

0.000E+000, E-DGOO-K-6B 1,

0.000E+000, E-PMOO-P-18A 1,

0.000E+000, F-PMOO-P-41 0.000E+000, F-PMOO-P-9A 0.000E+000, F-PMOO-P-9B 1,

0

. 0 0 0 E + 0 0 0.......

G-PMOO-P-55A 1,

0.000E+000, G-PMOO-P-55B 1,

0.000E+000, G-PMOO-P-55C 1,

0.000E+000, G-PMOO-P-56A 1,

0.000E+000, G-PMOO-P-56B 1,

0.000E+000, H-PMOO-P-66A 0.000E+0100, H-PMOO-P-66B 1,

0.000E+000, I-AD00-M-2 1,

0.000E+000, I-ADOO-M-2-1 0.000E+000, I-ADOO-M-2-2 1,

0.000E+000, I-CMOO-C-2A 1,

0.000E+000, I-CNOO-C-2B 1,

0.000E+000, I-CMOO-C-2C 11, 0.000E+000, IE-LOOP 1,

0

. 0 0 0 E + 0 0 0.......

IN-LOOP-EEC 1,

0.000E+000, IE LOOP 1,

0.000E+00,;,,

IE LOOP-REC 1,

O.O00E+000, L-PMOO-P-67A 1,

0.000E+000, L-PMOO-P-67B 1,

0.000E+000, P-BSOO-F-BUS 0.000E+000, P-BSOO-R-BUS 1,

0.000E+000, P-CBOO-ABB25R8 0.000E+000, P-CBOO-ABB27F7 1,

O.000E+0010, P-CBOO-ABB27H9 0.000E+000;,

P-CBOO-ABB27R8 0

. 0 0 0 E

, 0 0 0.......

P-CBOO-ABB29Fi O.000E+OC"'

P-'BOO-ABB29H9 0.000E+00 P-CBOO-ABB29R8 0.000

+000, P-CBOO-ABB31F7 O.O 0 0E+/-000, P-CBOO-ABB31H9 0.000E-!-000 Q-CMOO-C-6A 1,

0.

00E+000, Q-CMO0-C-6B

,,.000E+000, r

+2*"_00 C

6C 0.!v00E-000, S-PNOO-P-54.E=.

i, 2.000E+000, S-PMOO_P-54B 1,

0

. 0 0 0 E + 0 0 0.......

S-PMOO-P-54C 0.00'0E+000, U-PNOO-P-7A 0.000E-000.

U-PMOO-P-7B 0

. 0 0 0 E + 0 0 0.......

U-PMOO-P-7C C.000E+000, V-FNOO-V-I A 0.000E+/-000, A-2

LTR-PSA-08-01 April 4, 2008 Attachment A SAPHIRE CDF Change Set Data and Results V-FNOO-V-2A 0.005E+000.

V-FdCC-V-3A 1,

O.OOOE1-000,

'CLASS ECS SAPHIRE w!Safeguards Transformer Failed Change Set PROBABILITY HEADER Name

CalcType, UncType,

Prob, Lambda,

Tau,

` ncValue,

UrcCorr, MlssionT,

Flag, UncValue2 CLASS HEADER

Thee, Group, CompType

CompOd, System,

Location, Fa

lMode,

..rain,

!nit, Atti,,Att'_n CLASS PROBABILITY HEADER

CalcType, UncType,

Prob, Lambda,

Thu, U_scValue,

UncCorr, MissionT,

Flag, UncVaiue2

PSAR2C, OSG-CASES "PROBABILITY P-TIMT-EX-07

-CLASS "ECS SAPHIRE w/Safeguards Transformer and Front Bus Failed and Increased LOOP and Conditional LOOP Failure Probabilities Change Set PROBABILITY HEADER Name

CalcType, UncType,

Prob, Lambda,

Tau, UncVaiue,

UncCorr, MissionT,

Flag,

'U"ncva1ue2 CLASS HEADER

Name, Group,

CompType, CompId,

System, Location,

FailMode, Train,

Ioot, Att

,..,P_tt1C CLASS PROBABILITY HEADER

CalcType, UncType,

Prob, Lambda,

Tau, UncValue,

UncCorr, MissionT,

Flag, Unctialue2

PSAR2C, OSG-CASESA

^PROBABILITY P-TIMT-EX-07 T,

P-LOCP-24HR 4.480E-003, IE LCCP 1,

2.220E-002, P-BSMK-F-BUS

^CLASS

^ECS A-3

LTR-PSA-08-01 April 4, 2008 Attachment A SAPHIRE CDF Change Set Data and Results Table A-1: PSAR2c Zero Maintenance, EX-07 Failed, LOOP and Conditional LOOP Probabilities Changed (Top 100 Cutsets)

Cut No.

Basic Event

% Total Prob./Freq Description Event P rob.

1 10.22 2.87E-06 IE_LOSWS LOSS OF SERVICE WATER SYSTEM (IE FREQ) 1.22E-03 PP-PMMT-CCW-MBLOCA PRIMARY COOLANT PUMP SEAL FAILURE GIVEN A SBO AND CONSEQUENTIAL 235E-03 MEDIUM BREAK LOCA 2

19.8 2.69E-06 IE_CNTRLSD CONTROLLED MANUAL SHUTDOWN (IE FREQ) 2.43E+00 MTC2 PERCENTAGE OF TIME W/MTC NOT SUFFICIENTLY POSITIVE 2.30E-01

/RVO PRESSURIZER SAFETIES OPEN 9.99E-01 RXC-ELEC-FAULTS ELECTRICAL SCRAM SIGNAL FAULTS 4.81E-06 3

2434 1.27E-06 IE_CNTRLSD CONTROLLED MANUAL SHUTDOWN (IE FREQ) 2.43E+00 G-PMOE-P-55ABC OPERATOR FAILS TO INITIATE CHARGING FLOW 1.10E-01

/RVC PRESSURIZER SAFETIES CLOSED 9.91E-01

/RVO PRESSURIZER SAFETIES OPEN 9,99E-01 RXC-ELEC-FAULTS ELECTRICAL SCRAM SIGNAL FAULTS 4.81 E-06 4

27.92 1.00E-06 IE_SBLOCA LOSS OF COOLANT ACCIDENT - SMALL BRK [>0.4" and <2"] (IE FREQ) 2.26E-03 Y-AVMD-CV-3027 AIR OPERATED VALVE CV-3027 FAILS TO REMAIN OPEN 4.44E-04 5

31.5 1.00E-06 IE_SBLOCA LOSS OF COOLANT ACCIDENT - SMALL BRK [>0.4" and <2"] (IE FREQ) 2.26E-03 Y-AVMD-CV-3056 AIR OPERATED VALVE CV-3056 FAILS TO REMAIN OPEN 4.44E-04 6

34.35 7.99E-07 IE_SGTR STEAM GENERATOR TUBE RUPTURE 3.01 E-03 A-AVOA-AFWFLADJ OPERATOR FAILS TO ADJUST AFW FLOW GIVEN FAILURE OF ONE HDR 1.45E-03 H-ZZOA-OTC-CDTNL-HEP-2 COND HEP: A-AVOA-AFWFLADJ

• B-XVOB-ADVS-MAN

• H-ZZOA-OTC-INIT 3.66E-01 SGTRA FT TOP

STEAM GENERATOR TUBE RUPTURE ON SG A (developed event) 5.00E-01 7

37.2 7.99E-07 IE_SGTR STEAM GENERATOR TUBE RUPTURE 3.01E-03 A-AVOA-AFWFLADJ OPERATOR FAILS TO ADJUST AFW FLOW GIVEN FAILURE OF ONE HDR 1.45E-03 H-ZZOA-OTC-CDTNL-HEP-2 COND HEP: A-AVOA-AFWFLADJ

• B-XVOB-ADVS-MAN

• H-ZZOA-OTC-INIT 3.66E-01 SGTRB FT TOP

STEAM GENERATOR TUBE RUPTURE ON SG B (developed event) 5.00E-01 8

39.34 5.99E-07 IE_SGTR STEAM GENERATOR TUBE RUPTURE 3.01E-03 L-ZZOA-SDC-CDTNL-HEP-1 CONDITIONAL HEP: W-AVOA-PZR-SPRAY

• L-ZZOA-SDC-INIT 1.53E-01 W-AVOA-PZR-SPRAY OPERATOR FAILS TO DEPRESSURIZE PCS WITH PZR SPRAY/AUX SPRAY 1.30E-03 9

41.44 5.88E-07 IE SBLOCA LOSS OF COOLANT ACCIDENT - SMALL BRK [>0.4" and <2"] (IE FREQ) 2.26E-03 A-4

LTR-PSA-08-01 April 4, 2008 Attachment A SAPHIRE CDF Change Set Data and Results Table A-1: PSAR2c Zero Maintenance, EX-07 Failed, LOOP and Conditiona l LOOP Probabilities Changed (Top 1 00 Cutsets)

Cut

% Total Prob lFreq Basic Event Descri tion Event No.

p Prob.

Y-AVOB-RAS-VLVS OPERATOR FAILS TO ENABLE ESS RECIRC VALVES TO CLOSE ON RAS 2.60E-04 10 42.75 3.68E-07 IE LOOP LOSS OF OFFSITE POWER 2.22E-02 E-DG-ENGINE-REC-4HR EDG ENGINE RECOVERY IN 4 HOURS 4.30E-01 E-DGCC-K-6A&B&NSR-MG EDG1-1 EDG1-2 AND NSR COMMON CAUSE FAILURE TO RUN 3.44E-04 P-LOOP-REC-CORR-41R OFFSITE POWER CORRECTION FACTOR FOR EDG 24 HR RUN TIME-4 HR 3.27E-01 REC-30MIN RECOVERY OF OFFSITE POWER IN 30 MIN (PRIOR TO S/G DRYOUT) 7.30E-01 REC-4HR Recovery of Offsite Power in 4 Hours (prior to battery depletion) 4.70E-01 11 43.88 3.16E-07 IE_SBLOCA LOSS OF COOLANT ACCIDENT - SMALL BRK [>0.4" and <2"] (IE FREQ) 2.26E-03 Y-AVCC-3027-56MB BOTH SIRWT RECIRC VALVES CV-3027 & CV-3056 COMMON CAUSE FTC 1.40E-04 12 44.93 2.94E-07 IE_SBLOCA LOSS OF COOLANT ACCIDENT - SMALL BRK [>0.4" and <2"] (IE FREQ) 2,26E-03 Z-LSOH-SIRW-HI SIRW TANK LEVEL SWITCHES MISCALIBRATED HIGH 1.30E-04 13 45.98 2,94E-07 IE_SBLOCA LOSS OF COOLANT ACCIDENT - SMALL BRK [>0.4" and <2"] (IE FREQ) 2.26E-03 Z-LSOH-SIRW-LOW SIRW TANK LEVEL SWITCHES MISCALIBRATED LOW 1.30E-04 14 46.83 2.39E-07 IE_SBLOCA LOSS OF COOLANT ACCIDENT - SMALL BRK [>0.4" and <2"] (IE FREQ) 2.26E-03 Y-AVCC-SUMP-MA COMMON CAUSE FAILURE OF CV-3029 & CV-3030 TO OPEN 1.06E-04 15 47.62 2.20E-07 IE_CNTRLSD CONTROLLED MANUAL SHUTDOWN (IE FREQ) 2.43E+00 G-PMOE-P-55ABC OPERATOR FAILS TO INITIATE CHARGING FLOW 1.10E-01

/RVC PRESSURIZER SAFETIES CLOSED 9.91E-01

/RVO PRESSURIZER SAFETIES OPEN 9.99E-01

/RXC-ELEC-FAULTS ELECTRICAL SCRAM SIGNAL FAULTS 1.00E+00 RXC-MECH-FAULTS MECHANICAL SCRAM SIGNAL FAULTS 8.40E-07

/TTF TURBINE TRIP 9.90E-01 16 4&4 218E-07 IE-CNTRLSD CONTROLLED MANUAL SHUTDOWN (IE FREQ) 2.43E+00 A-PMMG-P-8B AFW TURBINE PUMP P-8B FAILS TO RUN 5.82E-02 E-DGCC-K-6A&B&NSR-MG EDG1-1 EDG1-2 AND NSR COMMON CAUSE FAILURE TO RUN 3.44E-04 E-HSE-EDG11-RUN SET TOT' -EDG11 RUN FAILURES ARE MODELED (House Event) 1.00E+00 E-HSE-EDG12-RUN SET TO 'T' -EDG12 RUN FAILURES ARE MODELED (House Event) 1.00E+00 P-LOOP-24HR LOOP COINCIDENT WITH ANOTHER IEVENT (24 HR MISSION TIME) 4.48E-03 A-5

LTR-PSA-08-01 April 4, 2008 Attachment A SAPHIRE CDF Change Set Data and Results Table A-1: PSAR2c Zero Maintenan ce, EX-07 Failed, LOOP a nd Cond itio nal LOOP Probabilities Changed (Top 100 Cutsets)

=o'/o To Pr bJFeq Basic Event Event

__._^.__._

Prob.

17 49.18 2.18E-07 IE_TRANS-WC TRANSIENT WITH THE MAIN CONDENSER AVAILABLE (IE FREQ) 1.97E-01 MTC2 PERCENTAGE OF TIME W/MTC NOT SUFFICIENTLY POSITIVE 2.30E-01

/RVO PRESSURIZER SAFETIES OPEN 9.99E-01 RXC-ELEC-FAULTS ELECTRICAL SCRAM SIGNAL FAULTS 4.81 E-06 18 49.94 2.12E-07 IE_LOOP LOSS OF OFFSITE POWER 2.22E-02 E-DGCC-K-6A&B&NSR-ME EDG1-1 EDG1-2 AND NSR COMMON CAUSE FAIL TO START 2.78E-05 REC-30MIN RECOVERY OF OFFSITE POWER IN 30 MIN (PRIOR TO S/G DRYOUT) 7.30E-01 REC-4HR Recovery of Offsite Power in 4 Hours (prior to battery depletion) 4.70E-01 19 50.39 1.27E-07 IE_LOSWS LOSS OF SERVICE WATER SYSTEM (IE FREQ) 1.22E-03 PP-PMMT-CCW-SBLOCA PRIMARY COOLANT PUMP SEAL FAILURE GIVEN A SBO AND CONSEQUENTIAL 1 04E-04 SMALL BREAK LOCH 20 50.8 1.15E-07 IE_SBLOCA LOSS OF COOLANT ACCIDENT - SMALL BRK [>0.4" and <2"] (IE FREQ) 2.26E-03 Y-PMCC-P8C66ABME COMMON CAUSE FAILURE OF P-8C 5.10E-05 21 51.17 1.04E-07 IE_LOOP LOSS OF OFFSITE POWER 2.22E-02 A-OOOT-CSTMK-CDTNL-HEP-2 COND HEP: L-ZZOA-SDC-INIT

• A-000T-CSTMKUP

• P-CBOB-BUS1 E 1.43E-01 H-ZZOA-OTC-INIT OPERATOR FAILS TO INITIATE ONCE THROUGH COOLING 2.90E-03 L-ZZOA-SDC-INIT OPERATOR FAILS TO INITIATE SDC 1.55E-02 REC-30MIN Recovery of Offsite Power in 30 min (prior to S/G dryout) 7.30E-01 22 51.54 1.03E-07 IE_TRANS-WC TRANSIENT WITH THE MAIN CONDENSER AVAILABLE (IE FREQ) 1.97E-01 G-PMOE-P-55ABC OPERATOR FAILS TO INITIATE CHARGING FLOW 1.10E-01

/RVC PRESSURIZER SAFETIES CLOSED 9.91E-01

/RVO PRESSURIZER SAFETIES OPEN 9.99E-01 RXC-ELEC-FAULTS ELECTRICAL SCRAM SIGNAL FAULTS 4.81E-06 23 51.9 1.01E-07 IE_CNTRLSD CONTROLLED MANUAL SHUTDOWN (IE FREQ) 2.43E+00 RVC PRESSURIZER SAFETIES CLOSED 8.61 E-03

/RVO PRESSURIZER SAFETIES OPEN 9.99E-01 RXC-ELEC-FAULTS ELECTRICAL SCRAM SIGNAL FAULTS 4.81 E-06 24 52.26 9.99E-08 IE_SGTR STEAM GENERATOR TUBE RUPTURE 3.01E-03 B-HCMA-HIC-0780A SDCR CONTROLLER HIC-0780A FAILS TO DE-ENERGIZE 1.14E-02 A-6

LTR-PSA-08-01 April 4, 2008 Attachment A SAPHIRE CDF Change Set Data and Results Ta ble A-1:

PSAR2c Zero Maintenance, EX-07 Failed, LOOP and Conditional LOOP Probabilities Changed (Top 100 Cutsets)

NoCut

'/.Totalj Prob.lFreq

-.-_.^

Basic Event Description Event Prob.

B-XVOB-ADVS-MAN OPERATOR FAILS TO CLOSE MANUAL VALVES TO CLOSE ADV 4.03E-02 L-ZZOA-SDC-CDTNL-HEP-2 CONDITIONAL HEP: B-XVOB-ADVS-MAN

• L-ZZOA-SDC-INIT 1.45E-01 SGTRA FT TOP

STEAM GENERATOR TUBE RUPTURE ON SG A (developed event) 5.00E-01 25 52.62 9.99E-08 IE_SGTR STEAM GENERATOR TUBE RUPTURE 3.01E-03 B-HCMA-HIC-0780A SDCR CONTROLLER HIC-0780A FAILS TO DE-ENERGIZE 1.14E-02 B-XVOB-ADVS-MAN OPERATOR FAILS TO CLOSE MANUAL VALVES TO CLOSE ADV 4.03E-02 L-ZZOA-SDC-CDTNL-HEP-2 CONDITIONAL HEP: B-XVOB-ADVS-MAN

• L-ZZOA-SDC-INIT 1.45E-01 SGTRB FT TOP

STEAM GENERATOR TUBE RUPTURE ON SG B (developed event) 5.00E-01 26 52.96 9.61 E-08 IE_SBLOCA LOSS OF COOLANT ACCIDENT - SMALL BRK [>0.4" and <2"] (IE FREQ) 2.26E-03 R-REMD-TVX-3 RELAY TVX-3 FAILS TO REMAIN DE-ENERGIZED 6.52E-03 R-REMD-TVX-4 RELAY TVX-4 FAILS TO REMAIN DE-ENERGIZED 6.52E-03 27 513 9.61 E-08 IE_SBLOCA LOSS OF COOLANT ACCIDENT - SMALL BRK [>0.4" and <2"] (IE FREQ) 2.26E-03 R-REMD-TVX-3 RELAY TVX-3 FAILS TO REMAIN DE-ENERGIZED 6.52E-03 R-REMD-TX-4 RELAY TX-4 FAILS TO REMAIN DE-ENERGIZED 6.52E-03 28 53.64 9.61E-08 IE_SBLOCA LOSS OF COOLANT ACCIDENT - SMALL BRK [>0.4" and <2"] (IE FREQ) 2.26E-03 R-REMD-TX-3 RELAY TX-3 FAILS TO REMAIN DE-ENERGIZED 6.52E-03 R-REMD-TX-4 RELAY TX-4 FAILS TO REMAIN DE-ENERGIZED 6.52E-03 29 53.98 9.61 E-08 IE-SBLOCA LOSS OF COOLANT ACCIDENT - SMALL BRK [>0.4" and <2"] (IE FREQ) 2.26E-03 R-REMD-TVX-4 RELAY TVX-4 FAILS TO REMAIN DE-ENERGIZED 6.52E-03 R-REMD-TX-3 RELAY TX-3 FAILS TO REMAIN DE-ENERGIZED 6.52E-03 30 54.32 9.58E-08 IE_SGTR STEAM GENERATOR TUBE RUPTURE 3.01E-03 L-TPMT-PT-0104A PRESSURE TRANSMITTER PT-0104A FAILS TO FUNCTION 2.45E-02 W-AVOA-PZR-SPRAY OPERATOR FAILS TO DEPRESSURIZE PCS WITH PZR SPRAY/AUX SPRAY 1.30E-03 31 54.66 9.58E-08 IE_SGTR STEAM GENERATOR TUBE RUPTURE 3.01E-03 L-TPMT-PT-0104B PRESSURE TRANSMITTER PT-0104B FAILS TO FUNCTION 2.45E-02 W-AVOA-PZR-SPRAY OPERATOR FAILS TO DEPRESSURIZE PCS WITH PZR SPRAY/AUX SPRAY 1.30E-03 32 54.94 7.90E-08 IE_SGTR STEAM GENERATOR TUBE RUPTURE 3.01E-03 L-TFMT-FT-0306 SDC INJECTION LINE FLOW TRANSMITTER FT-0306 FAILURE 2.02E-02 A-7

LT R-PSA-08-01 April 4, 2008 Attachment A SAPHIRE CDF Change Set Data and Results Table A-1: PSAR2c Zero M aintenance, EX-07 Fa iled, LOOP and Conditiona l LOOP Probabilities Changed (Top 100 Cutsets)

Cut o

/o Total

^^

Prob /Freq ^

Basic Event

^`

Descri tion Event No p

Prob.

W-AVOA-PZR-SPRAY OPERATOR FAILS TO DEPRESSURIZE PCS WITH PZR SPRAY/AUX SPRAY 1.30E-03 33 55.22 7.81 E-08 IE_LOMF-TRA LOSS OF FEEDWATER TRAIN A (IE FREQ) 7.07E-02 MTC2 PERCENTAGE OF TIME W/MTC NOT SUFFICIENTLY POSITIVE 2.30E-01

/RVO PRESSURIZER SAFETIES OPEN 9.99E-01 RXC-ELEC-FAULTS ELECTRICAL SCRAM SIGNAL FAULTS 4.81E-06 34 55.5 7.81E-08 IE_LOMF-TRB LOSS OF FEEDWATER TRAIN B (IE FREQ) 7.07E-02 MTC2 PERCENTAGE OF TIME W/MTC NOT SUFFICIENTLY POSITIVE 2.30E-01

/RVO PRESSURIZER SAFETIES OPEN 9.99E-01 RXC-ELEC-FAULTS ELECTRICAL SCRAM SIGNAL FAULTS 4.81E-06 35 55.76 7.22E-08 IE_CNTRLSD CONTROLLED MANUAL SHUTDOWN (IE FREQ) 2.43E+00 A-PMMG-P-8B AFW TURBINE PUMP P-8B FAILS TO RUN 5.82E-02 P-CBOB-BYREG WHEN "TRUE" OP RECOVERY OF THE BYPASS REG IS CREDITED 5.00E-01 P-IVCC-INVALL-MT COMMON CAUSE FAILURE OF FOUR INVERTERS TO CONTINUE TO OPERAT 1.02E-06 36 56.01 7.00E-08 IE_CNTRLSD CONTROLLED MANUAL SHUTDOWN (IE FREQ) 2.43E+00 A-OOOT-CSTMK-CDTNL-HEP-2 COND HEP: L-ZZOA-SDC-INIT

• A-OOOT-CSTMKUP

• P-CBOB-BUS1 E 1.43E-01 H-ZZOA-OTC-INIT OPERATOR FAILS TO INITIATE ONCE THROUGH COOLING 2.90E-03 L-ZZOA-SDC-INIT OPERATOR FAILS TO INITIATE SDC 1.55E-02 P-LOOP-24HR LOOP COINCIDENT WITH ANOTHER IEVENT (24 HR MISSION TIME) 4.48E-03 37 56.25 6.64E-08 IE_LOSWS LOSS OF SERVICE WATER SYSTEM (IE FREQ) 1.22E-03 A-PMCC-P8ABC-ME COMMON CAUSE FAILURE OF ALL 3 AFW PUMPS P-8A/B/C TO START 5.45E-05 38 56.49 6.64E-08 IE_SGTR STEAM GENERATOR TUBE RUPTURE 3.01E-03 L-HCMT-HIC-0306 SDC HX BYPASS VALVE HIC-0306B FAILS TO FUNCTION 1.70E-02 W-AVOA-PZR-SPRAY OPERATOR FAILS TO DEPRESSURIZE PCS WITH PZR SPRAY/AUX SPRAY 1.30E-03 39 56.73 6,64E-08 IE SGTR STEAM GENERATOR TUBE RUPTURE 3.01 E-03 L-HCMT-HIC-3025A SDC HX DISCHRG VALVE HAND INDIC CONTROLLER HIC-3025A FAIL 1.70E-02 W-AVOA-PZR-SPRAY OPERATOR FAILS TO DEPRESSURIZE PCS WITH PZR SPRAY/AUX SPRAY 1.30E-03 40 56.97 6.64E-08 IE SGTR STEAM GENERATOR TUBE RUPTURE 3.01E-03 L-HCMT-HIC-3025B SDC H X DISCHRG VALVE HAND INDIC CONTROLLER HIC-3025B FAIL 1.70E-02 A-8

LTR-PSA-08-01 April 4, 2008 Attachment A SAPHIRE CDF Change Set Data and Results Table A-1: PSAR2c Zero Maintenance, EX-07 Failed, LOOP and Conditiona l LOOP Probab ilit ies Changed (Top 100 Cutsets)

Cut Basic Event

^

Event No.

7° Total Prob.(Freq 1

I Description

^mmWYm Y

^

rob W-AVOA-PZR-SPRAY OPERATOR FAILS TO DEPRESSURIZE PCS WITH PZR SPRAY/AUX SPRAY 1.30E-03 41 57.21 6.64E-08 IE SGTR STEAM GENERATOR TUBE RUPTURE 3.01E-03 L-CEPO-POC-0306 SDC HX BYPASS POSITION CONTROLLER POC-0306 FAILS 1.70E-02 W-AVOA-PZR-SPRAY OPERATOR FAILS TO DEPRESSURIZE PCS WITH PZR SPRAY/AUX SPRAY 1.30E-03 42 57.45 6.64E-08 IE SGTR STEAM GENERATOR TUBE RUPTURE 3.01 E-03 L-CEPO-POC-3025 SDC HX DISCHARGE POSITION CONTROLLER POC-3025 FAILS 1.70E-02 W-AVOA-PZR-SPRAY OPERATOR FAILS TO DEPRESSURIZE PCS WITH PZR SPRAY/AUX SPRAY 1.30E-03 43 57.69 6.63E-08 IE_SBLOCA LOSS OF COOLANT ACCIDENT - SMALL BRK [>0.4" and <2"] (IE FREQ) 2.26E-03 Y-MVCC-ESS-ALL12 COMMON CAUSE FTO OF ALL 8 HPSI MOVS AND ALL 4 LPSI MOVS 2.94E-05 44 57.93 6.63E-08 IE_SBLOCA LOSS OF COOLANT ACCIDENT - SMALL BRK [>0.4" and <2"] (IE FREQ) 2.26E-03 H-MVCC-ESS-ALL8 COMMON CAUSE FTO OF ALL 8 HPSI MOVS 2.94E-05 45 58.15 6.19E-08 IE SGTR STEAM GENERATOR TUBE RUPTURE 3.01E-03 I-FLMK-F-28 CV-3025 LOCAL IA SUPPLY FILTER F28 PLUGGED 1.58E-02 W-AVOA-PZR-SPRAY OPERATOR FAILS TO DEPRESSURIZE PCS WITH PZR SPRAY/AUX SPRAY 1.30E-03 46 58.37 6.19E-08 IE SGTR STEAM GENERATOR TUBE RUPTURE 3.01E-03 Q-FLMK-F-310 SDC HX INLET VALVE HPA SUPPLY FILTER F-310 PLUGGED 1.58E-02 W-AVOA-PZR-SPRAY OPERATOR FAILS TO DEPRESSURIZE PCS WITH PZR SPRAY/AUX SPRAY 1.30E-03 47 58.59 6.17E-08 IE_MLBLOCA LOSS OF COOLANT ACCIDENT - MED LRGE BRK [>6" and <18"] (IE FREQ) 3.43E-05 H-AVOT-HL-INJ OPERATOR FAILS TO ALIGN HOT LEG INJECTION 1.80E-03 48 58.81 6,16E-08 IELOOP LOSS OF OFFSITE POWER 2.22E-02 E-DG-ENGINE-REC-4HR EDG ENGINE RECOVERY IN 4 HOURS 4.30E-01 E-DGMG-K-6A DIESEL GENERATOR 1-1 FAILS TO RUN 3.86E-02 E-DGMG-K-6B DIESEL GENERATOR 1-2 FAILS TO RUN 3.86E-02 E-DGMG-K-NSR NSR DIESEL GENERATOR FAILS TO RUN 3.86E-02 P-LOOP-REC-CORR-4HR OFFSITE POWER CORRECTION FACTOR FOR EDG 24 HR RUN TIME-4 HR 3.27E-01 REC-30MIN RECOVERY OF OFFSITE POWER IN 30 MIN (PRIOR TO S/G DRYOUT) 7.30E-01 REC-4HR Recovery of Offsite Power in 4 Hours (prior to battery depletion) 4.70E-01 49 59.03 6.04E -08 IE ISLOCA INTERFACING SYSTEMS LOCA (IE FREQ) 1.00E+00 A-9

LTR-PSA-08-01 April 4, 2008 Attachment A SAPHIRE CDF Change Set Data and Results Ta ble A-1IPSAR2c Zero Maintenance, EX-07 Failed, LOOP and Conditional LOOP Probabilities Changed (Top 100 Cutsets)

Cut No

% Total T Prob./Freq Basic Event Description Event Prob.

L-MVMJ-MO-3015 MOTOR OPERATED VALVE 3015 LEAKS (IE EVENT) 4.85E-03 L-MVMJ-MO-3016 MOTOR OPERATED VALVE 3016 LEAKS 1.33E-05 L-PIPE-GC-14 PIPE FAILS DUE TO PRIMARY CYCLE PRESSURE (GC 14 INCH) 9.37E-01 50 59.25 6.03E-08 IE_MBLOCA LOSS OF COOLANT ACCIDENT - MEDIUM BREAK [>2" and <6"] (IE FREQ) 3.35E-05 H-AVOT-HL-INJ OPERATOR FAILS TO ALIGN HOT LEG INJECTION 1.80E-03 51 59.46 5.80E-08 IE_LOMC LOSS OF MAIN CONDENSER VACUUM (IE FREQ) 5.25E-02 MTC2 PERCENTAGE OF TIME W/MTC NOT SUFFICIENTLY POSITIVE 2.30E-01

/RVO PRESSURIZER SAFETIES OPEN 9.99E-01 RXC-ELEC-FAULTS ELECTRICAL SCRAM SIGNAL FAULTS 4.81E-06 52 59.67 5.79E-08 IE_SBLOCA LOSS OF COOLANT ACCIDENT - SMALL BRK [>0.4" and <2"] (IE FREQ) 2.26E-03 R-REMD-TVX-4 RELAY TVX-4 FAILS TO REMAIN DE-ENERGIZED 6.52E-03 U-KVMA-SV-0821 SV-0821 FAILS TO DE-ENERGIZE 3.93E-03 53 59.88 5.79E-08 IE_SBLOCA LOSS OF COOLANT ACCIDENT - SMALL BRK [>0.4" and <2"] (IE FREQ) 2.26E-03 R-REMD-TX-4 RELAY TX-4 FAILS TO REMAIN DE-ENERGIZED 6.52E-03 U-KVMA-SV-0821 SV-0821 FAILS TO DE-ENERGIZE 3.93E-03 54 60.09 5.79E-08 IE_SBLOCA LOSS OF COOLANT ACCIDENT - SMALL BRK [>0.4" and <2"] (IE FREQ) 2.26E-03 R-REMD-TVX-4 RELAY TVX-4 FAILS TO REMAIN DE-ENERGIZED 6.52E-03 Y-KVMA-SV-0938 CCW TO SDC HX AIR SUPPLY SV-0938 FTD 3.93E-03 55 60.3 5.79E-08 IE_SBLOCA LOSS OF COOLANT ACCIDENT - SMALL BRK [>0.4" and <2"] (IE FREQ) 2.26E-03 R-REMD-TX-4 RELAY TX-4 FAILS TO REMAIN DE-ENERGIZED 6.52E-03 Y-KVMA-SV-0938 CCW TO SDC HX AIR SUPPLY SV-0938 FTD 3.93E-03 56 60.5 5.68E-08 IE-CNTRLSD CONTROLLED MANUAL SHUTDOWN (IE FREQ) 2.43E+00 P-CBMA-152-302 CIRCUIT BREAKER 152-302 FAILS TO OPEN 8.49E-03 U-FLCC-TRAV-SCRN COMMON CAUSE FAILURE OF TRAVELING SCREENS 2.75E-06 57 60.68 4.99E-08 IE_SBLOCA LOSS OF COOLANT ACCIDENT - SMALL BRK [>0.4" and <2"] (IE FREQ) 2.26E-03 Y-CVCC-SIRWT-MA BOTH SIRWT SUPPLY CK VALVES CK-ES3239 & CK-ES3240 CCAUSE FTO 2.21 E-05 58 60.86 4.99E-08 IE_SBLOCA LOSS OF COOLANT ACCIDENT - SMALL BRK [>0.4" and <2"] (IE FREQ) 2.26E-03 Y-CVCC-SUMP-MA BOTH SUMP SUPPLY CK VALVES CK-ES3166 & CK-ES318 1 CCAUSE FTO 2.21E-05 A-10

LTR-PSA-08-01 April 4, 2008 Attachment A SAPHIRE CDF Change Set Data and Results Table A-1 : PSAR2c Zero Maintenance, EX-07 Failed, LOOP and Conditional LOOP Probabilities Changed (Top 100 Cutsets)

Cut Q

/o Total No.

^

Prob./Freq I

Basic vent E

iiiiII n

L scriptio went Prob.

59 61.04 4.97E-08 IE_CNTRLSD CONTROLLED MANUAL SHUTDOWN (IE FREQ) 2.43E+00 A-PMMG-P-8B AFW TURBINE PUMP P-8B FAILS TO RUN 5.82E-02 P-CBOB-BYREG WHEN "TRUE" OP RECOVERY OF THE BYPASS REG IS CREDITED 5.00E-01 P-IVCC-INV-123MT COMMON CAUSE FAILURE OF THREE INVERTERS #1 7.03E-07 60 61.22 4.96E-08 IE._LOMSIV SPURIOUS MSIV CLOSURE (IE FREQ) 4.49E-02 MTC2 PERCENTAGE OF TIME W/MTC NOT SUFFICIENTLY POSITIVE 2.30E-01

/RVO PRESSURIZER SAFETIES OPEN 9.99E-01 RXC-ELEC-FAULTS ELECTRICAL SCRAM SIGNAL FAULTS 4.81E-06 61 61.4 4.96E-08 IE_SGTR STEAM GENERATOR TUBE RUPTURE 3.01 E-03 B-HCMB-HIC-0780A SDCR CONTROLLER HIC-0780A FAILS TO ENERGIZE 1.14E-02 H-ZZOA-OTC-INIT OPERATOR FAILS TO INITIATE ONCE THROUGH COOLING 2.90E-03 SGTRA FT TOP

STEAM GENERATOR TUBE RUPTURE ON SG A (developed event) 5.00E-01 62 61.58 4.96E-08 IE_SGTR STEAM GENERATOR TUBE RUPTURE 3.01E-03 B-HCMB-HIC-0780A SDCR CONTROLLER HIC-0780A FAILS TO ENERGIZE 1.14E-02 H-ZZOA-OTC-INIT OPERATOR FAILS TO INITIATE ONCE THROUGH COOLING 2.90E-03 SGTRB FT TOP

STEAM GENERATOR TUBE RUPTURE ON SG B (developed event) 5.00E-01 63 61.75 4.84E-08 IE_SBLOCA LOSS OF COOLANT ACCIDENT - SMALL BRK [>0.4" and <2"] (IE FREQ) 2.26E-03 H-CVCC-HPSIPP-MA BOTH HPSI PUMP DICHARGE CK VLVES CK-ES3177 & 3186 CCAUSE FTO 2.14E-05 64 61.92 4.84E-08 IE_SBLOCA LOSS OF COOLANT ACCIDENT - SMALL BRK [>0.4" and <2"] (IE FREQ) 2.26E-03 H-CVCC-RECIRC-MA BOTH HPSI PUMP RECIRC CK VLVS TO SIRWT COMMON CAUSE FTO 2.14E-05 65 62.09 4.84E-08 IE_SBLOCA LOSS OF COOLANT ACCIDENT - SMALL BRK [>0.4" and <2"] (IE FREQ) 2.26E-03 H-CVCC-SUCT-MA BOTH HPSI PUMP SUMP SUCTION CK VLVS COMMON CAUSE FTO 2.14E-05 66 62.26 4.76E-08 IE_SBLOCA LOSS OF COOLANT ACCIDENT - SMALL BRK [>0.4" and <2"] (IE FREQ) 2.26E-03 Y-CVCC-RECIRC-MA BOTH SIRWT RECIRC CK VALVES CK-ES3331 & ES3332 CCAUSE FTO 2.11E-05 67 62.42 4.46E-08 IE_LOOP LOSS OF OFFSITE POWER 212E-02 REC-30MIN RECOVERY OF OFFSITE POWER IN 30 MIN (PRIOR TO SIG DRYOUT) 7.30E-01 U-FLCC-TRAV-SCRN COMMON CAUSE FAILURE OF TRAVELING SCREENS 2.75E-06 68 62.58 4.42E-08 IE_SBLOCA LOSS OF COOLANT ACCIDENT - SMALL BRK [>0.4" and <2"] (IE FREQ) 2.26E-03 A-11

LTR-PSA-08-01 April 4, 2008 Attachment A SAPHIRE CDF Change Set Data and Results Table A-11: PSAR2c Zero Maintenance, EX-07 Failed, LOOP and Conditional LOOP Probabilities Changed (Top 100 Cutsets)

Cut No a

^^ Total Prob./Freq Basic Event Description Event Prob.

Y-AVMB-CV-3027 SIRWT RECIRC VALVE CV-3027 FTC 4.42E-03 Y-AVMB-CV-3056 SIRWT RECIRC VALVE CV-3056 FTC 4.42E-03 69 62.73 4.08E-08 IE_SBLOCA LOSS OF COOLANT ACCIDENT - SMALL BRK [>0.4" and <2"] (I E FREQ) 2.26E-03 Y-PMCC-P66AB-ME COMMON CAUSE FAILURE OF P-66A AND P-66B TO START 1.81 E-05 70 62.87 4.04E-08 IE_CNTRLSD CONTROLLED MANUAL SHUTDOWN (IE FREQ) 2.43E+00 MTC1 PERCENTAGE OF TIME W/MTC NOT SUFFICIENTLY POSITIVE 2.00E-02

/RVO PRESSURIZER SAFETIES OPEN 9.99E-01

/RXC-ELEC-FAULTS ELECTRICAL SCRAM SIGNAL FAULTS 1.00E+00 RXC-MECH-FAULTS MECHANICAL SCRAM SIGNAL FAULTS 8.40E-07

/TTF TURBINE TRIP 9.90E-01 71 6101 3.93E-08 IE_SBLOCA LOSS OF COOLANT ACCIDENT - SMALL BRK [>0.4" and <2"] (IE FREQ) 2.26E-03 Y-AVMB-CV-3027 SIRWT RECIRC VALVE CV-3027 FTC 4.42E-03 Y-KVMB-SV-3056B SIRWT RECIRC VALVE SOLENOID SV-3056B FTE 3.93E-03 72 63.15 3.93E-08 IE_SBLOCA LOSS OF COOLANT ACCIDENT - SMALL BRK [>0.4" and <2"] (IE FREQ) 2.26E-03 Y-AVMB-CV-3056 SIRWT RECIRC VALVE CV-3056 FTC 4.42E-03 Y-KVMB-SV-3027A SIRWT RECIRC VALVE SOLENOID SV-3027A FTE 3.93E-03 73 63.29 3.93E-08 IE_SBLOCA LOSS OF COOLANT ACCIDENT - SMALL BRK [>0.4" and <2"] (IE FREQ) 2.26E-03 Y-AVMB-CV-3056 SIRWT RECIRC VALVE CV-3056 FTC 4.42E-03 Y-KVMB-SV-3027B SIRWT RECIRC VALVE SOLENOID SV-3027B FTE 193E-03 74 63.43 193E-08 IE_SBLOCA LOSS OF COOLANT ACCIDENT - SMALL BRK [>0.4" and <2"] (IE FREQ) 2.26E-03 Y-AVMB-CV-3027 SIRWT RECIRC VALVE CV-3027 FTC 4.42E-03 Y-KVMB-SV-3056A SIRWT RECIRC VALVE SOLENOID SV-3056A FTE 3.93E-03 75 63.56 3.71 E-08 IE_LOMF-TRA LOSS OF FEEDWATER TRAIN A (IE FREQ) 7.07E-02 G-PMOE-P-55ABC OPERATOR FAILS TO INITIATE CHARGING FLOW 1.10E-01

/RVC PRESSURIZER SAFETIES CLOSED 9.91E-01

/RVO PRESSURIZER SAFETIES OPEN 9.99E-01 RXC-ELEC-FAULTS ELECTRICAL SCRAM SIGNAL FAULTS 4.81E-06 76 63.69 3.71 E-08 IE LOMF-TRB LOSS OF FEEDWATER TRAIN B (IE FR EQ) 7.07E-02 A-12

LTR-PSA-08-01 April 4, 2008 Attachment A SAPHIRE CDF Change Set Data and Results Table A-1: PSAR2c Zero Maintenance, EX-07 Failed, LOOP and Conditio nal LOOP Probabilities Changed (Top 100 Cutsets)

Cut o

^,, Total N

BEvent Prob.iFreq j

asic Description Event o.

rob.

G-PMOE-P-55ABC OPERATOR FAILS TO INITIATE CHARGING FLOW 1.10E-01

/RVC PRESSURIZER SAFETIES CLOSED 9.91E-01

/RVO PRESSURIZER SAFETIES OPEN 9.99E-01 RXC-ELEC-FAULTS ELECTRICAL SCRAM SIGNAL FAULTS 4.81E-06 77 63.82 3.65E-08 lr--CNTRLSD CONTROLLED MANUAL SHUTDOWN (IE FREQ) 2.43E+00 A-PMMG-P-8B AFW TURBINE PUMP P-8B FAILS TO RUN 5.82E-02 E-DGMG-K-6A DIESEL GENERATOR 1-1 FAILS TO RUN 3.86E-02 E-DGMG-K-6B DIESEL GENERATOR 1-2 FAILS TO RUN 3.86E-02 E-DGMG-K-NSR NSR DIESEL GENERATOR FAILS TO RUN 3.86E-02 E-HSE-EDG11-RUN SET TO 'T' -EDG11 RUN FAILURES ARE MODELED (House Event) 1.00E+00 E-HSE-EDG12-RUN SET TO'T' -EDG12 RUN FAILURES ARE MODELED (House Event) 1.00E+00 P-LOOP-24HR LOOP COINCIDENT WITH ANOTHER IEVENT (24 HR MISSION TIME) 4.48E-03 78 63.95 3.64E-08 IE_LOOP LOSS OF OFFSITE POWER 2.22E-02 A-PMMG-P-8B AFW TURBINE PUMP P-8B FAILS TO RUN 5.82E-02 E-DG-ENGINE-REC-2HR EDG ENGINE RECOVERY IN 2 HOURS 5.80E-01 E-DGCC-K-6A&B&NSR-MG EDG1-1 EDG1-2 AND NSR COMMON CAUSE FAILURE TO RUN 3.44E-04 E-HSE-EDG11-RUN SET TO 'T' -EDG11 RUN FAILURES ARE MODELED (House Event) 1.00E+00 E-HSE-EDG12-RUN SET TO'T' -EDG12 RUN FAILURES ARE MODELED (House Event) 1.00E+00 P-LOOP-REC-CORR-2HR OFFSITE POWER CORRECTION FACTOR FOR EDG 24 HR RUN TIME-2 HR 2.84E-01 REC-2HR RECOVERY OF OFFSITE POWER IN 2 HOURS (PRIOR TO CORE UNCOVERY) 6.80E-01 REC-30MIN RECOVERY OF OFFSITE POWER IN 30 MIN (PRIOR TO S/G DRYOUT) 7.30E-01 79 64.07 3.49E-08 IE_SBLOCA LOSS OF COOLANT ACCIDENT - SMALL BRK [>0.4" and <2"] (IE FREQ) 2.26E-03 Y-KVMB-SV-3027A SIRWT RECIRC VALVE SOLENOID SV-3027A FTE 3.93E-03 Y-KVMB-SV-3056B SIRWT RECIRC VALVE SOLENOID SV-3056B FTE 3.93E-03 80 64.19 3.49E-08 IE_SBLOCA LOSS OF COOLANT ACCIDENT - SMALL BRK [>0.4" and <2"] (IE FREQ) 2.26E-03 Y-KVMB-SV-3027B SIRWT RECIRC VALVE SOLENOID SV-3027B FTE 3.93E-03 Y-KVMB-SV-3056B SIRWT RECIRC VALVE SOLENOID SV-3056B FTE 3.93E-03 81 64.31 3.49E-08 IE SBLOCA LOSS OF COOLANT ACCIDENT - SMALL BRK [>0.4" and <2"] (IE FREQ) 2.26E-03 A-13

LTR-PSA-08-01 April 4, 2008 Attachment A SAPHIRE CDF Change Set Data and Results Tab le A-1: PSAR2c Zero Maintenance, EX-07 Failed, LOOP and Conditional LOOP Probabilities Changed (Top 1 00 Cutsets)

Cut No.

L

°7° Total Prob.(Freq L

Basic Event Description Event Prob.

Z-KVMB-SV-3029A SUMP TO EAST ESS AIR SUPPLY SV-3029A FTE 3.93E-03 Z-KVMB-SV-3030A SUMP TO WEST ESS AIR SUPPLY SV-3030A FTE 3.93E-03 82 64.43 3.49E-08 IE_SBLOCA LOSS OF COOLANT ACCIDENT - SMALL BRK [>0.4" and <2"] (IE FREQ) 2.26E-03 Z-KVMB-SV-3029B SUMP TO EAST ESS AIR SUPPLY SV-3029B FTE 3.93E-03 Z-KVMB-SV-3030A SUMP TO WEST ESS AIR SUPPLY SV-3030A FTE 3.93E-03 83 64.55 3.49E-08 IE_SBLOCA LOSS OF COOLANT ACCIDENT - SMALL BRK [>0.4" and <2"] (IE FREQ) 2.26E-03 Z-KVMB-SV-3029A SUMP TO EAST ESS AIR SUPPLY SV-3029A FTE 3.93E-03 Z-KVMB-SV-3030B SUMP TO WEST ESS AIR SUPPLY SV-3030B FTE 3.93E-03 84 64.67 3.49E-08 IE_SBLOCA LOSS OF COOLANT ACCIDENT - SMALL BRK [>0.4" and <2"] (IE FREQ) 2.26E-03 Z-KVMB-SV-3029B SUMP TO EAST ESS AIR SUPPLY SV-3029B FTE 3.93E-03 Z-KVMB-SV-3030B SUMP TO WEST ESS AIR SUPPLY SV-3030B FTE 3.93E-03 85 64.79 3.49E-08 IE_SBLOCA LOSS OF COOLANT ACCIDENT - SMALL BRK [>0.4" and <2"] (IE FREQ) 2.26E-03 Y-KVMB-SV-3027A SIRWT RECIRC VALVE SOLENOID SV-3027A FTE 3.93E-03 Y-KVMB-SV-3056A SIRWT RECIRC VALVE SOLENOID SV-3056A FTE 3.93E-03 86 64.91 3.49E-08 IE_SBLOCA LOSS OF COOLANT ACCIDENT - SMALL BRK [>0.4" and <2"] (IE FREQ) 2.26E-03 Y-KVMB-SV-3027B SIRWT RECIRC VALVE SOLENOID SV-3027B FTE 3.93E-03 Y-KVMB-SV-3056A SIRWT RECIRC VALVE SOLENOID SV-3056A FTE 3.93E-03 87 65.03 3.46E-08 IE_SGTR STEAM GENERATOR TUBE RUPTURE 3.01E-03 B-KVMA-SV-0782B ADV CV-0782 AIR SUPPLY SV-0782B FTD 3.93E-03 B-XVOB-ADVS-MAN OPERATOR FAILS TO CLOSE MANUAL VALVES TO CLOSE ADV 4.03E-02 L-ZZOA-SDC-CDTNL-HEP-2 CONDITIONAL HEP: B-XVOB-ADVS-MAN

• L-ZZOA-SDC-INIT 1.45E-01 SGTRA FT TOP

STEAM GENERATOR TUBE RUPTURE ON SG A (developed event) 5.00E-01 88 65.15 3.46E-08 IE_SGTR STEAM GENERATOR TUBE RUPTURE 3.01E-03 B-KVMA-SV-0781C ADV CV-0781 AIR SUPPLY SV-0781C FTD 3.93E-03 B-XVOB-ADVS-MAN OPERATOR FAILS TO CLOSE MANUAL VALVES TO CLOSE ADV 4.03E-02 L-ZZOA-SDC-CDTNL-HEP-2 CONDITIONAL HEP: B-XVOB-ADVS-MAN

• L-ZZOA-SDC-INIT 1.45E-01 SGTRA FT TOP

STEAM GENERATOR TUBE RUPTURE ON SG A (developed event) 5.00E-01 8965.27 3.46E-08 IE SGTR STEAM GENERATOR TUBE RUPTURE 3.01E-03 A-14

LTR-PSA-08-01 April 4, 2008 Attachment A SAPHIRE CDF Change Set Data and Results Tab le A-1 _ PSAR2c Zero Maintenance, EX-07 Failed, LOOP and Co ndit ional LOOP Probabilities Changed (Top 100 Cutsets)

CutT-No,

7. Total Prob.1Freq J^

Basic Event Description Event

Prob, B-KVMA-SV-0781B ADV CV-0781 AIR SUPPLY SV-0781B FTD 3.93E-03 B-XVOB-ADVS-MAN OPERATOR FAILS TO CLOSE MANUAL VALVES TO CLOSE ADV 4.03E-02 L-ZZOA-SDC-CDTNL-HEP-2 CONDITIONAL HEP: B-XVOB-ADVS-MAN

• L-ZZOA-SDC-INIT 1.45E-01 SGTRA FT TOP

STEAM GENERATOR TUBE RUPTURE ON SG A (developed event) 5.00E-01 90 65.39 3.46E-08 IE_SGTR STEAM GENERATOR TUBE RUPTURE 3.01E-03 B-KVMA-SV-0780C ADV CV-0780 AIR SUPPLY SV-0780C FTD 193E-03 B-XVOB-ADVS-MAN OPERATOR FAILS TO CLOSE MANUAL VALVES TO CLOSE ADV 4.03E-02 L-ZZOA-SDC-CDTNL-HEP-2 CONDITIONAL HEP: B-XVOB-ADVS-MAN

• L-ZZOA-SDC-INIT 1.45E-01 SGTRB FT TOP

STEAM GENERATOR TUBE RUPTURE ON SG B (developed event) 5.00E-01 91 65.51 3.46E-08 IE_SGTR STEAM GENERATOR TUBE RUPTURE 3.01E-03 B-KVMA-SV-0782C ADV CV-0782 AIR SUPPLY SV-0782C FTD 3.93E-03 B-XVOB-ADVS-MAN OPERATOR FAILS TO CLOSE MANUAL VALVES TO CLOSE ADV 4.03E-02 L-ZZOA-SDC-CDTNL-HEP-2 CONDITIONAL HEP: B-XVOB-ADVS-MAN

• L-ZZOA-SDC-INIT 1.45E-01 SGTRA FT TOP

STEAM GENERATOR TUBE RUPTURE ON SG A (developed event) 5.00E-01 92 65.63 3.46E-08 IE_SGTR STEAM GENERATOR TUBE RUPTURE 101E-03 B-KVMA-SV-0779B ADV CV-0779 AIR SUPPLY SV-0779B FTD 3.93E-03 B-XVOB-ADVS-MAN OPERATOR FAILS TO CLOSE MANUAL VALVES TO CLOSE ADV 4,03E-02 L-ZZOA-SDC-CDTNL-HEP-2 CONDITIONAL HEP: B-XVOB-ADVS-MAN

• L-ZZOA-SDC-INIT 1.45E-01 SGTRB FT TOP

STEAM GENERATOR TUBE RUPTURE ON SG B (developed event) 5.00E-01 93 65.75 3.46E-08 IE_SGTR STEAM GENERATOR TUBE RUPTURE 3.01 E-03 B-KVMA-SV-0779C ADV CV-0779 AIR SUPPLY SV-0779C FTD 3.93E-03 B-XVOB-ADVS-MAN OPERATOR FAILS TO CLOSE MANUAL VALVES TO CLOSE ADV 4.03E-02 L-ZZOA-SDC-CDTNL-HEP-2 CONDITIONAL HEP: B-XVOB-ADVS-MAN

• L-ZZOA-SDC-INIT 1.45E-01 SGTRB FT TOP

STEAM GENERATOR TUBE RUPTURE ON SG B (developed event) 5.00E-01 94 65.87 3.46E-08 IE_SGTR STEAM GENERATOR TUBE RUPTURE 3.01E-03 B-KVMA-SV-0780B ADV CV-0780 AIR SUPPLY SV-0780B FTD 3.93E-03 B-XVOB-ADVS-MAN OPERATOR FAILS TO CLOSE MANUAL VALVES TO CLOSE ADV 4.03E-02 L-ZZOA-SDC-CDTNL-HEP-2 CONDITIONAL HEP: B-XVOB-ADVS-MAN

• L-ZZOA-S DC-INIT 1.45E-01 A-15

LTR-PSA-08-01 April 4, 2008 Attachment A SAPHIRE CDF Change Set Data and Results Tab le A-1: PSAR2c Zero Maintenance, EX-07 Failed, LOOP and Conditional LOOP Probabilities Cha nged (Top 1 00 Cutsets)

Cut a7o Total N

^

ProbJFreq Basic Event Description Event F-Event o.

SGTRB FT TOP STEAM GENERATOR TUBE RUPTURE ON SG B (developed event) 5.00E-01 95 65.99 3.46E-08 IE_SGTR STEAM GENERATOR TUBE RUPTURE 3.01 E-03 B-KVMA-SV-0782C ADV CV-0782 AIR SUPPLY SV-0782C FTD 3.93E-03 B-XVOB-ADVS-MAN OPERATOR FAILS TO CLOSE MANUAL VALVES TO CLOSE ADV 4.03E-02 L-ZZOA-SDC-CDTNL-HEP-2 CONDITIONAL HEP: B-XVOB-ADVS-MAN

• L-ZZOA-SDC-INIT 1.45E-01 SGTRB FT TOP

STEAM GENERATOR TUBE RUPTURE ON SG B (developed event) 5.00E-01 X-HSE-SGA-BLDN SET TO 'T' - ESDE ON SG E-50A (House Event) 1.00E+00 96 66.11 3.46E-08 IE_SGTR STEAM GENERATOR TUBE RUPTURE 3.01E-03 B-KVMA-SV-0781B ADV CV-0781 AIR SUPPLY SV-0781B FTD 3.93E-03 B-XVOB-ADVS-MAN OPERATOR FAILS TO CLOSE MANUAL VALVES TO CLOSE ADV 4.03E-02 L-ZZOA-SDC-CDTNL-HEP-2 CONDITIONAL HEP: B-XVOB-ADVS-MAN

• L-ZZOA-SDC-INIT 1.45E-01 SGTRB FT TOP STEAM GENERATOR TUBE RUPTURE ON SG B (developed event) 5.00E-01 X-HSE-SGA-BLDN SET TO T' - ESDE ON SG E-50A (House Event) 1.00E+00 97 66.23 3.46E-08 IE_SGTR STEAM GENERATOR TUBE RUPTURE 3.01E-03 B-KVMA-SV-0781C ADV CV-0781 AIR SUPPLY SV-0781C FTD 3.93E-03 B-XVOB-ADVS-MAN OPERATOR FAILS TO CLOSE MANUAL VALVES TO CLOSE ADV 4.03E-02 L-ZZOA-SDC-CDTNL-HEP-2 CONDITIONAL HEP: B-XVOB-ADVS-MAN

• L-ZZOA-SDC-INIT 1.45E-01 SGTRB FT TOP

STEAM GENERATOR TUBE RUPTURE ON SG B (developed event) 5.00E-01 X-HSE-SGA-BLDN SET TO'T'- ESDE ON SG E-50A (House Event) 1.00E+00 98 66.35 3.46E-08 IE_SGTR STEAM GENERATOR TUBE RUPTURE 3.01E-03 B-KVMA-SV-0782B ADV CV-0782 AIR SUPPLY SV-0782B FTD 3.93E-03 B-XVOB-ADVS-MAN OPERATOR FAILS TO CLOSE MANUAL VALVES TO CLOSE ADV 4.03E-02 L-ZZOA-SDC-CDTNL-HEP-2 CONDITIONAL HEP: B-XVOB-ADVS-MAN

• L-ZZOA-SDC-INIT 1.45E-01 SGTRB FT TOP

STEAM GENERATOR TUBE RUPTURE ON SG B (developed event) 5.00E-01 X-HSE-SGA-BLDN SET TO 'T' - ESDE ON SG E-50A (House Event) 1.00E+00 99 66.47 3.46E-08 IE_SGTR STEAM GENERATOR TUBE RUPTURE 101E-03 B-KVMA-SV-0780C ADV CV-0780 AIR SUPPLY SV-0780C FTD 3.93E-03

--^

B-XVOB-ADVS-MAN OPERATOR FAILS TO CLOSE MANUAL VALVES TO CLOSE ADV 4.03E-02 A-16

LTR-PSA-08-01 April 4, 2008 Attachment A SAPHIRE CDF Change Set Data and Results Table A-1 :

PSAR2c Zero Maintenance, EX-07 Failed, LOOP and Conditional LOOP Probabilities Changed (Top 100 Cutsets)

Cut o

Basic Event Total Prob./Freq Description No

/o Event Prob.

L-ZZOA-SDC-CDTNL-HEP-2 CONDITIONAL HEP: B-XVOB-ADVS-MAN

• L-ZZOA-SDC-INIT 1.45E-01 SGTRA FT TOP

STEAM GENERATOR TUBE RUPTURE ON SG A (developed event) 5.00E-01 X-HSE-SGB-BLDN SET TO 'T' - ESDE ON SG E-50B (House Event) 1.00E+00 100 66.59 3.46E-08 IE_SGTR STEAM GENERATOR TUBE RUPTURE 3.01E-03 B-KVMA-SV-0780B ADV CV-0780 AIR SUPPLY SV-0780B FTD 3.93E-03 B-XVOB-ADVS-MAN OPERATOR FAILS TO CLOSE MANUAL VALVES TO CLOSE ADV 4.03E-02 L-ZZOA-SDC-CDTNL-HEP-2 CONDITIONAL HEP: B-XVOB-ADVS-MAN

• L-ZZOA-SDC-INIT 1.45E-01 SGTRA FT TOP

STEAM GENERATOR TUBE RUPTURE ON SG A (developed event) 5.00E-01 X-HSE -SGB-BLDN SET TO 'T' - ESDE ON SG E-50B (House Event) 1.00E+00 Cut No.

%a Total Prob./Freq In itial,,

Ta b le A-2 : Top Ten Cutsets with Noun Failure Descriptors Event Failure Definitions - Outsets 10 42 75 3 68E-07 Loss of Offsite Failure to Repair EDG 1-1, 1-2 and LOOP Probability Failure to Failure to Power (I E)

EDGs in 4 Hrs 1-3 CCause FTR Correction Factor Recover OSP in Recover OSP in f(time) 30 min 4 Hrs 16 48.4 2.18E-07 Controlled Manual EDG 1-1, 1-2 and P-8B FTR

-1, 1-LOSP 24 Hr Conditional Shutdown (IE) 1-3 CCause FTR Failure 18 49.94 2,12E-07 Loss of Offsite EDG 1-1, 1-2 and Failure to Recover OSP in Failure to Recover OSP in Power (IE}

1-3 CCause FTS 30 min 4 Hrs 21 51.17 1 04E-07 Loss of Offsite HEP Conditional Operator fails to Operator fails to Failure to Power (IE)

Probability initiage OTC align SDC Recover OSP in 30 min 36 56.01 7 00E-08 Controlled Manual HEP Conditional Operator fails to Operator fails to LOSP 24 Hr Shutdown (IE)

Probability initiage OTC align SDC Conditional Failure 48 58.81 6.16E-08 Loss of Offsite Power (I E)

Failure to Repair EDGs in 4 Hrs EDG 1-1 FTR EDG 1-2 FTR EDG 1-3 FTR LOOP Probability Failure to Failure to Correction Factor Recover OSP in Recover OSP in Controlled f(time) 30 min 4 Hrs 56 60.5 5.68E-08 Manual CB 152-302 FTO Traveling Screen Shutdown (IE)

CCause Failure 67 62.42 4.46E-08 Loss of Offsite Failure to Traveling Screen Power (I E)

Recover OSP in CCause Failure A-17

LTR-PSA-08-01 April 4, 2008 Attachment A SAPHIRE CDF Change Set Data and Results Table A-2: Top Ten Outsets with Noun Fail ure Descriptors Cut No. 1 % Total rob./Freq In itiator Event Failure Definitions -Outsets 30 min Controlled LOSP 24 Hr 77 63.82 165E-08 Manual P-8B FTR EDG 1-1 FTR EDG 1-2 FTR EDG 1-3 FTR Conditional Shutdown (IE)

Failure Loss of Offsite Failure to Repair EDG 1-1, 1-2 and LOOP Probability Failure to Failure to 78 63.95 164E-08 Power (I E)

P-8B FTR EDGs in 2 Hrs 1-3 CCause FTR Correction Factor Recover OSP in Recover OSP in f(time) 2 H rs 30 min A-18

LTR-PSA-08-01 April 4, 2008 Attachment B SAPHIRE LERF Change Set Data and Results Table of Contents SAPHIRE w/Safeguards Transformer Failed and B-2 Increased LOOP and Conditional LOOP Failure Probabilities Change Set (Plant Damage State Analysis)

SAPHIRE w/Safeguards Transformer Failed and B-2 Increased LOOP and Conditional LOOP Failure Probabilities Change Set (CET Analysis)

Table B-1: PSAR2c Zero Maintenance, E-H (LERF)

B-5 Only (Top 25 Cutsets)

Table B-2: PSAR2c Zero Maintenance, EX-07 B-11 Failed, LOOP and Conditional LOOP Probabilities

Changed, E-H (LERF) Only (Top 25 Cutsets)

Table B-3: Comparison of Tables B-1 and B-2 (Top B-26 100 Cutsets)

B-1

LTR-PSA-08-01 April 4, 2008 Attachment B SAPHIRE LERF Change Set Data and Results SAPHIRE Zero Maintenance Unavailabilities Change Set (PDS Analysis)

PROBABILITY H EADER Name CalcTyp e,

UncTvpe, ProH,

Lambda, Tau,

U cVal u e, UncCorr,

MWssionT, Flap, CncVal-.ue2 CLASS HEADER

Name, Group,

CompType,

Compld, System,

Location, FailMode,

Train,

!nit, Attl,, Att?6 CLASS PROBABILITY H EADE R CalcType

UncType, Pro b,

Lambda, Tau, UncValue,

UncCorr, Miss

onT, Flaq, UncValue2

PSAR2C, MAINT UNAVAIL(0)

"PROBABILITY A-PMOC - P-SA 1

0.000E+000,

A-PMOO - P-8B 1,

0.000E+000,

A-PMOO-P - SC O.OOOE+000,

C-PMOO-P-52A 0.000E + 000, C-PMOO-P-52B 1,

0.000E+000,

C-PMOO-P-52C 1,

0.000E+000,

D-BCOO-ED-15 1,

0.000E+000,

D-BCOO-ED-16 0.000E+000,

D-BCOO-ED-17 1,

.,.000E+000,

D-BCOO-ED-18 1,

O.OOOE+000,

E-DGOO-K-6A 1,

0.000E+000,

E-DGOO-K-66B 1,

0.000E+000,

E-PMOO-P-18A 1,

0.000E+000,

F-PMOO-P-41 1,

0.000E+000,

F-PMOO-P-9A 1,

0.000E+000,

F-PMOO-P-9B 1,

0.000E + C0G, G-PMOO-P-55A 0.000E+000,

G-PMOO-P-55B 1,

0.000E+000,

G-PMOO-P-55C 1,

0.000E+000,

G-PMOO-P-56A 1,

0.000E+000,

G-PMOO-P-56B 1,

0.000E+000,

H-PMOO-P-66A 1,

0.000E+000,

H-PMOO-P-66B 0.000E+000,

I-ADOO-M-2 1,

0.000E+000,

I-ADOO-M-2-1 1,

0.000E+000,

I-ADOO-M-2 -2 1,

0.0000E+000,

I-CMOO-C-2A 1,

0.000E+000,

-CMOO-C-2B 1,

0.0005+ © 00, I-CMOO-C-2C i,

0.000E+000,

IE-LOOP 1,

0.000E+000,

IE LOOP REC 0.000E+000 IE LOOP 1,

0

. 000E+000, IE LOOP-REC 1,

0.000E+000,

L-PMOO-P-67A 1,

0.000E+000,

L-PMOO-P-67B 1,

0.000E+000,

P-BSOO-F-BUS 1,

0.000E+000,

P-BSOO-R-BUS 1,

0.000E+000, P-CBOO-ABB25R 8 0.000E+000.

P-CBOO-AEB27F 7 1,

0.000E+000,

P-CBOO-ABB27HB 0.000E+000,

P-CBOO-ABB27R8 0.000E + 000, P-CB00-ABB29F7 0.000E+000,

p-CBOO - ABB29H9 0.000E +000, P-CBOG-AB B 29R8 0.000E+00001 P-CBOO-ABB 1FI

0. 000E-00 0, P-CBOO-ABB01H9 0.,--100E+000,

Q-CM0O-C - 6A_

0.000E+000,

T-CMOO-C-6B

,,. 000E+000,

r r

Q-CMOO-C-SC 0.0 00E+000, S-PMOO-P-54A D.000E+000, S-PMOO-P-54B 0.000E+000,

S-PM00-P-54C

0. 000E+0 ;;0, U-PMOO-P-7A 0

. 000E+000, U-PMO^O-P - 7B 0.000E+000,

U-PMOO-P-7C 0.000E+000,

V-FNOO-V-IA 0.000E+000,

B-2

LTR-PSA-08-01 April 4, 2008 Attachment B SAPHIRE LERF Change Set Data and Results V-FNCO-V-2A 0,

0 r

r, r

r r

V-FEOC-V-3A 1,

0.000E+000.

r r

r,,

t C<,ASS EOS SAPHIRE w/Safeguards Transformer Failed and Increased LOOP and Conditional LOOP Failure Probabilities Change Set (Plant Damage State Analysis)

PROEABIL°^_Y HEADER Name

CalcTe, UncT yn yp°,

Prot, Lambda,

Tau, UncValue,

UncCorr, MissionT,

Flaa, UncValue2 C LASS HEADER

Name, Group,

CompType, Compld,

System, Location, Fail-Mode,

rain,

!nit, Rttl,,Atti6 CLASS PROBABILITY HEADER

CalcType, UncType,

Prot, Lambda,

Tau, UncValue,

UncCorr, MissionT,

Flag, UncValue2 PSAR2C

POS, EX-07

=

'PROBABILITY P-T1MT-EX-G7 T,

P-LOOP-24HR 4.480E-00.3, r

IE LOOP 2.220E-002, r

r "CLASS "EOS SAPHIRE w/Safeguards Transformer Failed and Increased LOOP and Conditional LOOP Failure Probabilities Change Set (CET Analysis)

PROBABILITY HEADER Name

CalcType, Uncoype,

Prob, Lambda,

`au,

UncValue, UncCorr,

MissionT, Flag, UncValue2 CLASS HEADER

Name, Group,

CompType, Compld,

System, Location,

FaiiMode, Train,

lnit, Attl,..,Attl6 CLASS PROBABILITY HEADER

CalcType, UncType,

Prot, Lambda,

Tau, UncValue,

UncCorr, Miss

onT, Flag, Uncvalue2 SAMA-CET, CET-PSAR2C-OOS-REMOVED-BCase

=

'PROBABILITY CET

ESP

,7.493E-6, r

CE-TP-PORVS, 1,

,4.84E-1, r

r CET CEGP 5.359E-6r CE-MP-PORVS, 1,

,0.EO, CF.T DEJS 4.372E-6, r

CE-TW-PORVS, 1,

,4.029E-1, CET BEIP

,3.671E-6, r

r CE-MB-PORVS, 1,

1.E0.

r r

CET A2EGR 2.997E-6, CE-TV-PORVS, I,

,1.E0, r

CET BEGR

,2.556E-6, r

r r

CE-MV-PCRVS,

,0.EO, r

CET BEGV 1.031E-6, CS-TR-PORVS,

.Elr t

r CET TEJV4

, 3.132E-6, r

r

,O.EC.

. E CET TEJS 4.283E-7, CE-TS-PORVS, 1.E,-

CET BEGS 3.95E-7, r

CE-MS -PORVS,

.E" CET A2ECP

.63E-.,

CE-Th-PORVS,

,9.82SE-1, CET TEJP F

6r r

r CE-M

-PO 2VS,

, 3.E0.

r r

r CET OEJR 3.58-32-8 r

r e

r CE-B2-PORV',

1,

,9.934E-1, r

CET MEJ

,6._26E-9, r

r CE-BR-PCRVS,

.993E-'_

r r

CET AIEGR

,5.145E-9, r

CE-BS-,uRVS, 1,

1.E0, B-3

LTR-PSA-08-01 April 4, 2008 Attachment B SAPHIRE LERF Change Set Data and Results CET TEJQ 1_.063E-7, CE-BV-PORVS, 1,

9

. 9 2 7 E - 1......

CET TEJR I.G99E

?,

CE-DS-PCRVS, 1,

,9.96E-1, CET TEJV

,3.997E-a CE-DP-PORVS, 1,

,5.258E-1, CET ME,JP

, S

. EC, CE-PR-PCRVS, 1,

,6.495E-3, CET MEJV O.EC, CE-F2P-PCRVS, I,

,9.428E-CET YEJR

,O.EO, CE-P2R-PORVS, 1

9.9-9E-1, CET MEJS

,O-Eu CE-AlR-PORVS,

,1.EO, CET MEJQ

,O.EO, CE-ZP-PORVS,

,9.967E-I, CET CEJW

,,.907E 8,

'CLASS

^ECS B-4

LT R-PSA-08-01 April 4, 2008 Attachment B SAPHIRE LERF Change Set Data and Results Table B-1: PSAR2c Zero Maintenance, E-H (LERF ) Only (Top 25 Cutsets)

Cut No.

Total Prob./Freq Basic Event Description Event Prob.

1 29.42 7.43E-08 CETCEJW PDS FREQ I ISLOCA NO CACS + NO SPRAYS + NO SIRWT + NO S/G COOLING 7.91E-08

/CE-CW-CAVSMPDRNS CAVITY SUMP DRAINS OPEN (NO MOD) 1.00E+00 CE-CW-CSP CONTAINMENT SPRAY FAILED EARLY 1.00E+00

/CE-CW-CSPRECRIV CONTAINMENT SPRAY RECOVERED FOR VESSEL PROTECTION 1.00E+00 CE-CW-ISLOCA INTERFACING SYSTEM LOCA INITIATOR 1.00E+00 CE-CW-NCCVDBCNFG DEBRIS CONFIG IN CAVITY NON-COOLABLE 9.90E-01 CE-CW-VFTIMELONG TIME TO VESSEL FAILURE AFTER CORE RELOCATION VERY LONG 9.50E-01

/CE-CW-VSSLIMPNG VESSEL FAILS DUE TO DEBRIS IMPINGEMENT 9.99E-01 2

33.62 1.06E-08 CET_A2EGR PDS FREQ I MLARGE LOCA I CACS+SIRWT + S/G COOLING 3.00E-06

/CE-2R-CAVSMPDRNS CAVITY SUMP DRAINS OPEN (NO MOD) 1.00E+00 CE-2R-CIS CONTAINMENT ISOLATION SUCCESS 9.95E-01 CE-2R-CSP CONTAINMENT SPRAY FAILED EARLY 1.00E+00

/CE-2R-CSPRECRIV CONTAINMENT SPRAY RECOVERED FOR EX-VESSEL PROTECTION 1.00E+00 CE-2R-INVSLSTEXP IN VESSEL STEAM EXPLOSION FAILS CONTAINMENT 5.00E-03 CE-2R-MBLOCA MEDIUM BREAK LOCA INITIATOR 1,00E+00 CE-2R-NCCVDBCNFG DEBRIS CONFIG IN CAVITY NON-COOLABLE 7.50E-01

/CE-2R-PCSRETEN SIGNIFICANT RETENTION OF PCS FISSION PRODUCTS 1,00E+00 CE-2R-VFTIMELONG TIME TO VESSEL FAILURE AFTER CORE RELOCATION VERY LONG 9.50E-01

/CE-2R-VSSLIMPNG VESSEL FAILS DUE TO DEBRIS IMPINGEMENT 9.99E-01 3

37.82 1.06E-08 CET_A2EGR PDS FREQ I MLARGE LOCA I CACS+SIRWT + S/G COOLING 3.00E-06

/CE-2R-CAVSMPDRNS CAVITY SUMP DRAINS OPEN (NO MOD) 1.00E+00 CE-2R-CIS CONTAINMENT ISOLATION SUCCESS 9.95E-01 CE-2R-CSP CONTAINMENT SPRAY FAILED EARLY 1.00E+00

/CE-2R-CSPRECRIV CONTAINMENT SPRAY RECOVERED FOR EX-VESSEL PROTECTION 1.00E+00 CE-2R-EXVSLSTEXP EX VESSEL STEAM EXPLOSION FAILS CONTAINMENT 5.00E-03 CE-2R-MBLOCA MEDIUM BREAK LOCA INITIATOR 1.00E+00 CE-2R-NCCVDBCNFG DEBRIS CONFIG IN CAVITY NON-COOLABLE 7.50E-01

/CE-2R-PCSRETEN SIGNIFICANT RETENTION OF PCS FISSION PRODUCTS 1.00E+00 CE-2R-VFTIMELONG TIME TO VESSEL FAILURE AFTER CORE RELOCATION VERY LONG 9.50E-01

/CE-2R-VSSLIMPNG VESSEL FAILS DUE TO DEBRIS IMPINGEMENT 9.99E-01 4

41.47 9.21E-09 CET-_ZEGP PDS FREQ I ATWS I SPRAYS + CACS + S/G COOLING 5.32E-06 CE-ZP-CIS CONTAINMENT ISOLATION SUCCESS 9.95E-01

/CE-ZP-CSP CONTAINMENT SPRAY FAILED EARLY 1.00E+00

/CE-ZP-CSPFAILRIV ACCIDENT PROGRESSION FAILS CONTAINMENT SPRAY 9.50E-01 B-5

LTR-PSA-08-01 April 4, 2008 Attachment B SAPHIRE LERF Change Set Data and Results Table B-1: PSAR2c Zero Maintenance, E-H (LERF ) Only (Top 25 Cutsets)

Cut No.

Prob./Freq Basic Event Description went Total Prob.

/CE-ZP-CVFLOODSYS CAVITY FLOODING SYSTEM FAILED mm 9.84E-01 CE-ZP-INVSSLH2 SUFFICIENT H2 PRODUCTION IN VESSEL TO FAIL CONTAINMENT 7.92E-03

/CE-ZP-MSLBICFRAC CORE MELT FREQUENCY FRACTION FOR MSLB INSIDE CONTAINMENT 1.00E+00

/CE-ZP-MSLBOCFRAC MAIN STEAM LINE BREAK OUTSIDE CONTAINMENT 1.00E+00 CE-ZP-PCSDEPRESS PCS DEPRESSURIZES PRIOR TO VESSEL FAILURE 9.50E-01 CE-ZP-PCSRETEN SIGNIFICANT RETENTION OF PCS FISSION PRODUCTS 5.50E-01 CE-ZP-PZSRVFTC PZR CODE SAFETY FAILS OPEN 4.75E-01

/CE-ZP-SECONDCOOL ALL S/G SECONDARY COOLING FAILED 1.00E+00

/CE-ZP-SGTUBEFAIL HEATING INDUCES S/G TUBE(S) FAILURE 9.98E-01 CE-ZP-TRANSIENT TURBINE TRIP INITIATOR 1.00E+00 CE-ZP-VSSLHTXFER HEAT TRANSFER FROM DEBRIS POOL PREDOMINANTLY UPWARD 9.50E-01

/CE-ZP-VSSLIMPNG VESSEL FAILS DUE TO DEBRIS IMPINGEMENT 9.99E-01 5

44.86 8.55E-09 CET_ZEGP PDS FREQ I ATWS I SPRAYS + CACS + S/G COOLING 5.32E-06 CE-ZP-CIS CONTAINMENT ISOLATION SUCCESS 9.95E-01

/CE-ZP-CSP CONTAINMENT SPRAY FAILED EARLY 1.00E+00

/CE-ZP-CSPFAILRIV ACCIDENT PROGRESSION FAILS CONTAINMENT SPRAY 9.50E-01

/CE-ZP-CVFLOODSYS CAVITY FLOODING SYSTEM FAILED 9.84E-01 CE-ZP-HOTLEGFAIL HEATING INDUCES HOT LEG FAILURE 4.41E-01 CE-ZP-INVSSLH2 SUFFICIENT H2 PRODUCTION IN VESSEL TO FAIL CONTAINMENT 7.92E-03

/CE-ZP-MSLBICFRAC CORE MELT FREQUENCY FRACTION FOR MSLB INSIDE CONTAINMENT 1.00E+00

/CE-ZP-MSLBOCFRAC MAIN STEAM LINE BREAK OUTSIDE CONTAINMENT 1.00E+00 CE-ZP-PCSDEPRESS PCS DEPRESSURIZES PRIOR TO VESSEL FAILURE 9.50E-01 CE-ZP-PCSRETEN SIGNIFICANT RETENTION OF PCS FISSION PRODUCTS 5.50E-01

/CE-ZP-SECONDCOOL ALL S/G SECONDARY COOLING FAILED 1.00E+00

/CE-ZP-SGTUBEFAIL HEATING INDUCES S/G TUBE(S) FAILURE 9.98E-01 CE-ZP-TRANSIENT TURBINE TRIP INITIATOR 1.00E+00 CE-ZP-VSSLHTXFER HEAT TRANSFER FROM DEBRIS POOL PREDOMINANTLY UPWARD 9.50E-01

/CE-ZP-VSSLIMPNG VESSEL FAILS DUE TO DEBRIS IMPINGEMENT 9.99E-01 6

48.14 8.29E-09 CET_ZEGP PDS FREQ I ATWS I SPRAYS + CACS + S/G COOLING 5.32E-06 CE-ZP-CIS CONTAINMENT ISOLATION SUCCESS 9.95E-01

/CE-ZP-CSP CONTAINMENT SPRAY FAILED EARLY 1.00E+00

/CE-ZP-CSPFAIL ACCIDENT PROGRESSION FAILS CONTAINMENT SPRAYS LATE 9.00E-01

/CE-ZP-CSPFAILRIV ACCIDENT PROGRESSION FAILS CONTAINMENT SPRAY 9.50E-01

/CE_ZP-CVFLOODSYS CAVITY FLOODING SYSTEM FAILE D 9.84E-01 B-6

LTR-PSA-08-01 April 4, 2008 Attachment B SAPHIRE LERF Change Set Data and Results Table B-1: PSAR2c Zero Maintenance, E-H (LERF) Only (Top 25 Cutsets) 1 Cut No.

Total Prob./Freq Basic Event Description Event Prob.

CE-ZP-INVSSLH2 SUFFICIENT H2 PRODUCTION IN VESSEL TO FAIL CONTAINMENT 7.92E-03

/CE-ZP-MSLBICFRAC CORE MELT FREQUENCY FRACTION FOR MSLB INSIDE CONTAINMENT 1.00E+00

/CE-ZP-MSLBOCFRAC MAIN STEAM LINE BREAK OUTSIDE CONTAINMENT 1.00E+00 CE-ZP-PCSDEPRESS PCS DEPRESSURIZES PRIOR TO VESSEL FAILURE 9.50E-01 CE-ZP-PCSRETEN SIGNIFICANT RETENTION OF PCS FISSION PRODUCTS 5.50E-01 CE-ZP-PZSRVFTC PZR CODE SAFETY FAILS OPEN 4.75E-01

/CE-ZP-SGTUBEFAIL HEATING INDUCES S/G TUBE(S) FAILURE 9,98E-01 CE-ZP-TRANSIENT TURBINE TRIP INITIATOR 1.00E+00 CE-ZP-VSSLHTXFER HEAT TRANSFER FROM DEBRIS POOL PREDOMINANTLY UPWARD 9.50E-01

/CE-ZP-VSSLIMPNG VESSEL FAILS DUE TO DEBRIS IMPINGEMENT 9.99E-01 7

51.19 7.70E-09 CET_ZEGP PDS FREQ I ATWS I SPRAYS + CACS + S/G COOLING 5.32E-06 CE-ZP-CIS CONTAINMENT ISOLATION SUCCESS 9.95E-01

/CE-ZP-CSP CONTAINMENT SPRAY FAILED EARLY 1.00E+00

/CE-ZP-CSPFAIL ACCIDENT PROGRESSION FAILS CONTAINMENT SPRAYS LATE 9.00E-01

/CE-ZP-CSPFAILRIV ACCIDENT PROGRESSION FAILS CONTAINMENT SPRAY 9.50E-01

/CE-ZP-CVFLOODSYS CAVITY FLOODING SYSTEM FAILED 9.84E-01 CE-ZP-HOTLEGFAIL HEATING INDUCES HOT LEG FAILURE 4.41E-01 CE-ZP-INVSSLH2 SUFFICIENT H2 PRODUCTION IN VESSEL TO FAIL CONTAINMENT 7.92E-03

/CE-ZP-MSLBICFRAC CORE MELT FREQUENCY FRACTION FOR MSLB INSIDE CONTAINMENT 1.00E+00

/CE-ZP-MSLBOCFRAC MAIN STEAM LINE BREAK OUTSIDE CONTAINMENT 1.00E+00 CE-ZP-PCSDEPRESS PCS DEPRESSURIZES PRIOR TO VESSEL FAILURE 9.50E-01 CE-ZP-PCSRETEN SIGNIFICANT RETENTION OF PCS FISSION PRODUCTS 5.50E-01

/CE-ZP-SGTUBEFAIL HEATING INDUCES S/G TUBE(S) FAILURE 9.98E-01 CE-ZP-TRANSIENT TURBINE TRIP INITIATOR 1.00E+00 CE-ZP-VSSLHTXFER HEAT TRANSFER FROM DEBRIS POOL PREDOMINANTLY UPWARD 9.50E-01

/CE-ZP-VSSLIMPNG VESSEL FAILS DUE TO DEBRIS IMPINGEMENT 9.99E-01 8

54.24 7.69E-09 CET_BEGP PDS FREQ I SMALL LOCA I SPRAYS + CACS + SIG COOLING 3.67E-06 CE-BP-CIS CONTAINMENT ISOLATION SUCCESS 9.95E-01

/CE-BP-CSP CONTAINMENT SPRAY FAILED EARLY 1.00E+00

/CE-BP-CSPFAILRIV ACCIDENT PROGRESSION FAILS CONTAINMENT SPRAY 9.50E-01

/CE-BP-CVFLOODSYS CAVITY FLOODING SYSTEM FAILED 9.84E-01 CE-BP-EXVSLSTEXP EX VESSEL STEAM EXPLOSION FAILS CONTAINMENT 5.00E-03 CE-BP-PCSDEPRESS PCS DEPRESSURIZES PRIOR TO VESSEL FAILURE 9.50E-01 CE-BP-PCSRETEN SIGNIFICANT RETENTION OF PCS FISSION PRODUCTS 5.00E-01 B-7

LTR-PSA-08-01 April 4, 2008 Attachment B SAPHIRE LERF Change Set Data and Results Table B-1: PSAR2c Zero Maintenance, E-H (LERF ) Only (Top 25 Cutsets)

Cut No.

Prob.tFreq Basic Event To%ta l Description Event Prob.

CE-BP-SBLOCA SBLOCA INITIATOR 1.00E+00

/CE-BP-SECONDCOOL ALL S/G SECONDARY COOLING FAILED 1.00E+00 CE-BP-VSSLHTXFER HEAT TRANSFER FROM DEBRIS POOL PREDOMINANTLY UPWARD 9.50E-01

/CE-BP-VSSLIMPNG VESSEL FAILS DUE TO DEBRIS IMPINGEMENT 9.99E-01 9

56.98 6.92E-09 CET_BEGP PDS FREQ I SMALL LOCA I SPRAYS + CACS + S/G COOLING 167E-06 CE-BP-CIS CONTAINMENT ISOLATION SUCCESS 9.95E-01

/CE-BP-CSP CONTAINMENT SPRAY FAILED EARLY 1,0pE+00

/CE-BP-CSPFAIL ACCIDENT PROGRESSION FAILS CONTAINMENT SPRAYS LATE 9.00E-01

/CE-BP-CSPFAILRIV ACCIDENT PROGRESSION FAILS CONTAINMENT SPRAY 9.50E-01

/CE-BP-CVFLOODSYS CAVITY FLOODING SYSTEM FAILED 9.84E-01 CE-BP-EXVSLSTEXP EX VESSEL STEAM EXPLOSION FAILS CONTAINMENT 5.00E-03 CE-BP-PCSDEPRESS PCS DEPRESSURIZES PRIOR TO VESSEL FAILURE 9.50E-01

/CE-BP-PCSRETEN SIGNIFICANT RETENTION OF PCS FISSION PRODUCTS 5.00E-01 CE-BP-SBLOCA SBLOCA INITIATOR 1.00E+00 CE-BP-VSSLHTXFER HEAT TRANSFER FROM DEBRIS POOL PREDOMINANTLY UPWARD 9.50E-01

/CE-BP-VSSLIMPNG VESSEL FAILS DUE TO DEBRIS IMPINGEMENT 9.99E-01 10 59.72 6.92E-09 CET_BEGP PDS FREQ I SMALL LOCA I SPRAYS + CACS + SIG COOLING 3.67E-06 CE-BP-CIS CONTAINMENT ISOLATION SUCCESS 9.95E-01

/CE-BP-CSP CONTAINMENT SPRAY FAILED EARLY 1.00E+00

/CE-BP-CSPFAIL ACCIDENT PROGRESSION FAILS CONTAINMENT SPRAYS LATE 9.00E-01

/CE-BP-CSPFAILRIV ACCIDENT PROGRESSION FAILS CONTAINMENT SPRAY 9.50E-01

/CE-BP-CVFLOODSYS CAVITY FLOODING SYSTEM FAILED 9.84E-01 CE-BP-EXVSLSTEXP EX VESSEL STEAM EXPLOSION FAILS CONTAINMENT 5.00E-03 CE-BP-PCSDEPRESS PCS DEPRESSURIZES PRIOR TO VESSEL FAILURE 9.50E-01 CE-BP-PCSRETEN SIGNIFICANT RETENTION OF PCS FISSION PRODUCTS 5.00E-01 CE-BP-SBLOCA SBLOCA INITIATOR 1.00E+00 CE-BP-VSSLHTXFER HEAT TRANSFER FROM DEBRIS POOL PREDOMINANTLY UPWARD 9.50E-01

/CE-BP-VSSLIMPNG VESSEL FAILS DUE TO DEBRIS IMPINGEMENT 9.99E-01 11 62.41 6.78E-09 CET_ZEGP PDS FREQ I ATWS I SPRAYS + CACS + S/G COOLING 5.32E-06 CE-ZP-CIS CONTAINMENT ISOLATION SUCCESS 9.95E-01

/CE-ZP-CSP CONTAINMENT SPRAY FAILED EARLY 1.00E+00

/CE-ZP-CSPFAIL ACCIDENT PROGRESSION FAILS CONTAINMENT SPRAYS LATE 9.00E-01

/CE-ZP-CSPFAILRIV ACCIDENT PROGRESSION FAILS CONTAINMENT SPRAY 9.50E-01

/CE-ZP-CVFLOODSYS CAVITY FLOODING SYSTEM FAILED 9.84E-01 B-8

LTR-PSA-08-01 April 4, 2008 Attachment B SAPHIRE LERF Change Set Data and Results Table B-1: PSAR2c Zero Maintenance, E-H (LERF ) Only (Top 25 Cutsets)

Cut No.

Total Prob./Freq Basic Event Description Event Prob.

CE-ZP-INVSSLH2 SUFFICIENT H2 PRODUCTION IN VESSEL TO FAIL CONTAINMENT 7.92E-03

/CE-ZP-MSLBICFRAC CORE MELT FREQUENCY FRACTION FOR MSLB INSIDE CONTAINMENT 1.00E+00

/CE-ZP-MSLBOCFRAC MAIN STEAM LINE BREAK OUTSIDE CONTAINMENT 1.00E+00 CE-ZP-PCSDEPRESS PCS DEPRESSURIZES PRIOR TO VESSEL FAILURE 9.50E-01

/CE-ZP-PCSRETEN SIGNIFICANT RETENTION OF PCS FISSION PRODUCTS 4.50E-01 CE-ZP-PZSRVFTC PZR CODE SAFETY FAILS OPEN 4.75E-01

/CE-ZP-SGTUBEFAIL HEATING INDUCES S/G TUBE(S) FAILURE 9.98E-01 CE-ZP-TRANSIENT TURBINE TRIP INITIATOR 1.00E+00 CE-ZP-VSSLHTXFER HEAT TRANSFER FROM DEBRIS POOL PREDOMINANTLY UPWARD 9.50E-01

/CE-ZP-VSSLIMPNG VESSEL FAILS DUE TO DEBRIS IMPINGEMENT 9.99E-01 12 64.9 6.30E-09 CET_ZEGP PDS FREQ I ATWS I SPRAYS + CACS + SIG COOLING 5.32E-06 CE-ZP-CIS CONTAINMENT ISOLATION SUCCESS 9.95E-01

/CE-ZP-CSP CONTAINMENT SPRAY FAILED EARLY 1.00E+00

/CE-ZP-CSPFAIL ACCIDENT PROGRESSION FAILS CONTAINMENT SPRAYS LATE 9.00E-01

/CE-ZP-CSPFAILRIV ACCIDENT PROGRESSION FAILS CONTAINMENT SPRAY 9.50E-01

/CE-ZP-CVFLOODSYS CAVITY FLOODING SYSTEM FAILED 9.84E-01 CE-ZP-HOTLEGFAIL HEATING INDUCES HOT LEG FAILURE 4.41E-01 CE-ZP-INVSSLH2 SUFFICIENT H2 PRODUCTION IN VESSEL TO FAIL CONTAINMENT 7.92E-03

/CE-ZP-MSLBICFRAC CORE MELT FREQUENCY FRACTION FOR MSLB INSIDE CONTAINMENT 1.00E+00

/CE-ZP-MSLBOCFRAC MAIN STEAM LINE BREAK OUTSIDE CONTAINMENT 1.00E+00 CE-ZP-PCSDEPRESS PCS DEPRESSURIZES PRIOR TO VESSEL FAILURE 9.50E-01

/CE-ZP-PCSRETEN SIGNIFICANT RETENTION OF PCS FISSION PRODUCTS 4.50E-01

/CE-ZP-SGTUBEFAIL HEATING INDUCES S/G TUBE(S) FAILURE 9.98E-01 CE-ZP-TRANSIENT TURBINE TRIP INITIATOR 1.00E+00 CE-ZP-VSSLHTXFER HEAT TRANSFER FROM DEBRIS POOL PREDOMINANTLY UPWARD 9.50E-01

/CE-ZP-VSSLIMPNG VESSEL FAILS DUE TO DEBRIS IMPINGEMENT 9.99E-01 13 67.2 5.82E-09 CET_ZEGP PDS FREQ I ATWS I SPRAYS + CACS + S/G COOLING 5.32E-06 CE-ZP-CIS CONTAINMENT ISOLATION SUCCESS 9.95E-01

/CE-ZP-CSP CONTAINMENT SPRAY FAILED EARLY 1.00E+00

/CE-ZP-CSPFAILRIV ACCIDENT PROGRESSION FAILS CONTAINMENT SPRAY 9.50E-01

/CE-ZP-CVFLOODSYS CAVITY FLOODING SYSTEM FAILED 9.84E-01 CE-ZP-EXVSLSTEXP EX VESSEL STEAM EXPLOSION FAILS CONTAINMENT 5.00E-03

/CE-ZP-MSLBICFRAC CORE MELT FREQUENCY FRACTION FOR MSLB INSIDE CONTAINMENT 1.00E+00 ICE-ZP-MSLBOCFRAC MAIN STEAM LINE BREAK OUTSIDE CONTAINMENT 1.00E+00 B-9

LTR-PSA-08-01 April 4, 2008 Attachment B SAPHIRE LERF Change Set Data and Results Table B-1: PSAR2c Zero Maintenance, E-H (LERF) Only (Top 25 Cutsets) 1 Cut No.

Prob./Freq Total Basic Event Description Event Prob.

CE-ZP-PCSDEPRESS PCS DEPRESSURIZES PRIOR TO VESSEL FAILURE 9.50E-01 CE-ZP-PCSRETEN SIGNIFICANT RETENTION OF PCS FISSION PRODUCTS 5.50E-01 CE-ZP-PZSRVFTC PZR CODE SAFETY FAILS OPEN 4.75E-01

/CE-ZP-SECONDCOOL ALL S/G SECONDARY COOLING FAILED 1.00E+00

/CE-ZP-SGTUBEFAIL HEATING INDUCES S/G TUBE(S) FAILURE 9.98E-01 CE-ZP-TRANSIENT TURBINE TRIP INITIATOR 1.00E+00 CE-ZP-VSSLHTXFER HEAT TRANSFER FROM DEBRIS POOL PREDOMINANTLY UPWARD 9.50E-01

/CE-ZP-VSSLIMPNG VESSEL FAILS DUE TO DEBRIS IMPINGEMENT 9.99E-01 14 69.34 5.40E-09 CET_._ZEGP PDS FREQ I ATWS I SPRAYS + CACS + SIG COOLING 5.32E-06 CE-ZP-CIS CONTAINMENT ISOLATION SUCCESS 9.95E-01

/CE-ZP-CSP CONTAINMENT SPRAY FAILED EARLY 1.00E+00

/CE-ZP-CSPFAILRIV ACCIDENT PROGRESSION FAILS CONTAINMENT SPRAY 9.50E-01

/CE-ZP-CVFLOODSYS CAVITY FLOODING SYSTEM FAILED 9.84E-01 CE-ZP-EXVSLSTEXP EX VESSEL STEAM EXPLOSION FAILS CONTAINMENT 5.00E-03 CE-ZP-HOTLEGFAIL HEATING INDUCES HOT LEG FAILURE 4.41E-01

/CE-ZP-MSLBICFRAC CORE MELT FREQUENCY FRACTION FOR MSLB INSIDE CONTAINMENT 1.00E+00

/CE-ZP-MSLBOCFRAC MAIN STEAM LINE BREAK OUTSIDE CONTAINMENT 1.00E+00 CE-ZP-PCSDEPRESS PCS DEPRESSURIZES PRIOR TO VESSEL FAILURE 9.50E-01 CE-ZP-PCSRETEN SIGNIFICANT RETENTION OF PCS FISSION PRODUCTS 5.50E-01

/CE-ZP-SECONDCOOL ALL S/G SECONDARY COOLING FAILED 1.00E+00

/CE-ZP-SGTUBEFAIL HEATING INDUCES S/G TUBE(S) FAILURE 9.98E-01 CE-ZP-TRANSIENT TURBINE TRIP INITIATOR 1.00E+00 CE-ZP-VSSLHTXFER HEAT TRANSFER FROM DEBRIS POOL PREDOMINANTLY UPWARD 9.50E-01

/CE-ZP-VSSLIMPNG VESSEL FAILS DUE TO DEBRIS IMPINGEMENT 9.99E-01 15 71.41 5.23E-09 CET_ZEGP PDS FREQ I ATWS I SPRAYS + CACS + S/G COOLING 5.32E-06 CE-ZP-CIS CONTAINMENT ISOLATION SUCCESS 9.95E-01

/CE-ZP-CSP CONTAINMENT SPRAY FAILED EARLY 1.00E+00

/CE-ZP-CSPFAIL ACCIDENT PROGRESSION FAILS CONTAINMENT SPRAYS LATE 9.00E-01

/CE-ZP-CSPFAILRIV ACCIDENT PROGRESSION FAILS CONTAINMENT SPRAY 9.50E-01

/CE-ZP-CVFLOODSYS CAVITY FLOODING SYSTEM FAILED 9.84E-01 CE-ZP-EXVSLSTEXP EX VESSEL STEAM EXPLOSION FAILS CONTAINMENT 5.00E-03

/CE-ZP-MSLBICFRAC CORE MELT FREQUENCY FRACTION FOR MSLB INSIDE CONTAINMENT 1.00E+00

/CE-ZP-MSLBOCFRAC MAIN STEAM LINE BREAK OUTSIDE CONTAINMENT 1.00E+00 CE-ZP-PCSDEPRESS PCS DEPRESSURIZES PRIOR TO VESSEL FAILURE 9.50E-01 B-10

LTR-PSA-08-01 April 4, 2008 Attachment B SAPHIRE LERF Change Set Data and Results Table B-1: PSAR2c Zero Maintenance, E-H (SERF ) Only (Top 25 Cutsets)

C ut No.

I Total ProbiFreq Basic Event Description Cvent Prob.

CE-ZP-PCSRETEN SIGNIFICANT RETENTION OF PCS FISSION PRODUCTS 5.50E-01 CE-ZP-PZSRVFTC PZR CODE SAFETY FAILS OPEN 4.75E-01

/CE-ZP-SGTUBEFAIL HEATING INDUCES S/G TUBE(S) FAILURE 9.98E-01 CE-ZP-TRANSIENT TURBINE TRIP INITIATOR 1.00E+00 CE-ZP-VSSLHTXFER HEAT TRANSFER FROM DEBRIS POOL PREDOMINANTLY UPWARD 9.50E-01

/CE-ZP-VSSLIMPNG VESSEL FAILS DUE TO DEBRIS IMPINGEMENT 9.99E-01 16 7333 4.86E-09 CET__ZEGP PDS FREQ I ATWS I SPRAYS + CACS + S/G COOLING 532E-06 CE-ZP-CIS CONTAINMENT ISOLATION SUCCESS 9.95E-01

/CE-ZP-CSP CONTAINMENT SPRAY FAILED EARLY 1.00E+00

/CE-ZP-CSPFAIL ACCIDENT PROGRESSION FAILS CONTAINMENT SPRAYS LATE 9.00E-01

/CE-ZP-CSPFAILRIV ACCIDENT PROGRESSION FAILS CONTAINMENT SPRAY 9.50E-01

/CE-ZP-CVFLOODSYS CAVITY FLOODING SYSTEM FAILED 9.84E-01 CE-ZP-EXVSLSTEXP EX VESSEL STEAM EXPLOSION FAILS CONTAINMENT 5.00E-03 CE-ZP-HOTLEGFAIL HEATING INDUCES HOT LEG FAILURE 4.41E-01

/CE-ZP-MSLBICFRAC CORE MELT FREQUENCY FRACTION FOR MSLB INSIDE CONTAINMENT 1.00E+00

/CE-ZP-MSLBOCFRAC MAIN STEAM LINE BREAK OUTSIDE CONTAINMENT 1.00E+00 CE-ZP-PCSDEPRESS PCS DEPRESSURIZES PRIOR TO VESSEL FAILURE 9.50E-01 CE-ZP-PCSRETEN SIGNIFICANT RETENTION OF PCS FISSION PRODUCTS 5.50E-01

/CE-ZP-SGTUBEFAIL HEATING INDUCES S/G TUBE(S) FAILURE 9.98E-01 CE-ZP-TRANSIENT TURBINE TRIP INITIATOR 1.00E+00 CE-ZP-VSSLHTXFER HEAT TRANSFER FROM DEBRIS POOL PREDOMINANTLY UPWARD 9.50E-01

/CE-ZP-VSSLIMPNG VESSEL FAILS DUE TO DEBRIS IMPINGEMENT 9.99E-01 17 75.03 4.28E-09 CET_ZEGP PDS FREQ I ATWS I SPRAYS + CACS + S/G COOLING 5.32E-06 CE-ZP-CIS CONTAINMENT ISOLATION SUCCESS 9.95E-01

/CE-ZP-CSP CONTAINMENT SPRAY FAILED EARLY 1.00E+00

/CE-ZP-CSPFAIL ACCIDENT PROGRESSION FAILS CONTAINMENT SPRAYS LATE 9.00E-01

/CE-ZP-CSPFAILRIV ACCIDENT PROGRESSION FAILS CONTAINMENT SPRAY 9.50E-01

/CE-ZP-CVFLOODSYS CAVITY FLOODING SYSTEM FAILED 9.84E-01 CE-ZP-EXVSLSTEXP EX VESSEL STEAM EXPLOSION FAILS CONTAINMENT 5.00E-03

/CE-ZP-MSLBICFRAC CORE MELT FREQUENCY FRACTION FOR MSLB INSIDE CONTAINMENT 1.00E+00

/CE-ZP-MSLBOCFRAC MAIN STEAM LINE BREAK OUTSIDE CONTAINMENT 1.00E+00 CE-ZP-PCSDEPRESS PCS DEPRESSURIZES PRIOR TO VESSEL FAILURE 9.50E-01

/CE-ZP-PCSRETEN SIGNIFICANT RETENTION OF PCS FISSION PRODUCTS 4.50E-01 PZR CODE SAFETY FAILS OPEN 4.75E-01 B-11

QTR-PSA-08-01 April 4, 2008 Attachment B SAPHIRE SERF Change Set Data and Results Table B-1: PSAR2c Zero Maintenance, E-H (SERF) Only (Top 25 Cutsets)

I Cut No.

I Prob./Freq Basic Event Total Description Event 1

Prob.

/CE-ZP-SGTUBEFAIL HEATING INDUCES SIG TUBE(S) FAILURE 9.98E-01 CE-ZP-TRANSIENT TURBINE TRIP INITIATOR 1.00E+00 CE-ZP-VSSLHTXFER HEAT TRANSFER FROM DEBRIS POOL PREDOMINANTLY UPWARD 9.50E-01

/CE-ZP-VSSLIMPNG VESSEL FAILS DUE TO DEBRIS IMPINGEMENT 9.99E-01 18 76.6 3.98E-09 CET_ZEGP PDS FREQ I ATWS I SPRAYS + CACS + SIG COOLING 5.32E-06 CE-ZP-CIS CONTAINMENT ISOLATION SUCCESS 9.95E-01

/CE-ZP-CSP CONTAINMENT SPRAY FAILED EARLY 1.00E+00

/CE-ZP-CSPFAIL ACCIDENT PROGRESSION FAILS CONTAINMENT SPRAYS LATE 9.00E-01

/CE-ZP-CSPFAILRIV ACCIDENT PROGRESSION FAILS CONTAINMENT SPRAY 9.50E-01

/CE-ZP-CVFLOODSYS CAVITY FLOODING SYSTEM FAILED 9.84E-01 CE-ZP-EXVSLSTEXP EX VESSEL STEAM EXPLOSION FAILS CONTAINMENT 5.00E-03 CE-ZP-HOTLEGFAIL HEATING INDUCES HOT LEG FAILURE 4.41E-01

/CE-ZP-MSLBICFRAC CORE MELT FREQUENCY FRACTION FOR MSLB INSIDE CONTAINMENT 1.00E+00

/CE-ZP-MSLBOCFRAC MAIN STEAM LINE BREAK OUTSIDE CONTAINMENT 1.00E+00 CE-ZP-PCSDEPRESS PCS DEPRESSURIZES PRIOR TO VESSEL FAILURE 9.50E-01 ICE-ZP-PCSRETEN SIGNIFICANT RETENTION OF PCS FISSION PRODUCTS 4.50E-01

/CE-ZP-SGTUBEFAIL HEATING INDUCES S/G TUBE(S) FAILURE 9.98E-01 CE-ZP-TRANSIENT TURBINE TRIP INITIATOR 1.00E+00 CE-ZP-VSSLHTXFER HEAT TRANSFER FROM DEBRIS POOL PREDOMINANTLY UPWARD 9.50E-01

/CE-ZP-VSSLIMPNG VESSEL FAILS DUE TO DEBRIS IMPINGEMENT 9.99E-01 19 78.07 3.72E-09 CET_CEJW PDS FREQ

( ISLOCA I NO CACS + NO SPRAYS + NO SIRWT + NO S/G COOLING 7.91 E-08

/CE-CW-CAVSMPDRNS CAVITY SUMP DRAINS OPEN (NO MOD) 1.00E+00 CE-CW-ISLOCA INTERFACING SYSTEM LOCA INITIATOR 1.00E+00 CE-CW-NCCVDBCNFG DEBRIS CONFIG IN CAVITY NON-COOLABLE 9.90E-01 CE-CW-VFTIMELONG TIME TO VESSEL FAILURE AFTER CORE RELOCATION VERY LONG 9.50E-01

/CE-CW-VSSLHTXFER HEAT TRANSFER FROM DEBRIS POOL PREDOMINANTLY UPWARD 5.00E-02

/CE-CW-VSSLIMPNG VESSEL FAILS DUE TO DEBRIS IMPINGEMENT 9.99E-01 20 79.01 2.38E-09 CET_BEGR PDS FREQ I SMALL LOCA I CACS+SIRWT + SIG COOLING 2.56E-06

/CE-BR-CAVSMPDRNS CAVITY SUMP DRAINS OPEN (NO MOD) 1.00E+00 CE-BR-CIS CONTAINMENT ISOLATION SUCCESS 9.95E-01 CE-BR-CSP CONTAINMENT SPRAY FAILED EARLY 1.00E+00

/CE-BR-CSPRECRIV CONTAINMENT SPRAY RECOVERED FOR EX-VESSEL PROTECTION 1.00E+00 CE-BR-EXVSLSTEXP EX VESSEL STEAM EXPLOSION FAILS CONTAINMENT 5.00E-03 CE-BR-NCCVDBCNFG DEBRIS CONFIG IN CAVITY NON-COOLAB LE 7.50E-01 B-12

LTR-PSA-08-01 April 4, 2008 Attachment B SAPHIRE LERF Change Set Data and Results Table B-1: PSAR2c Zero Maintenance, E-H (LERF) Only (Top 25 Cutsets) 1 Cut No.

I Prob.tFreq Total I Basic Event I

Description Event L^

1 Prob.

/CE-BR-PCSRETEN SIGNIFICANT RETENTION OF PCS FISSION PRODUCTS 5.00E-01 CE-BR-SBLOCA SBLOCA INITIATOR 1.00E+00 CE-BR-VFTIMELONG TIME TO VESSEL FAILURE AFTER CORE RELOCATION VERY LONG 5.00E-01

/CE-BR-VSSLIMPNG VESSEL FAILS DUE TO DEBRIS IMPINGEMENT 9.99E-01 21 79.78 1.96E-09 CET_CEJW PDS FREQ I ISLOCA I NO CACS + NO SPRAYS + NO SIRWT + NO S/G COOLING 7.91 E-08

/CE-CW-CAVFLRFAIL CAVITY FLOOR CATASTROPHIC FAILURE EARLY 1.00E+00

/CE-CW-CAVSMPDRNS CAVITY SUMP DRAINS OPEN (NO MOD) 1.00E+00 CE-CW-CRDBAFTBD MOST OF THE CORE DEBRIS EXITS THE VESSEL AFTER BLOWDOWN 5.00E-01 CE-CW-CSP CONTAINMENT SPRAY FAILED EARLY 1.00E+00

/CE-CW-CSPRECRIV CONTAINMENT SPRAY RECOVERED FOR VESSEL PROTECTION 1.00E+00 CE-CW-ISLOCA INTERFACING SYSTEM LOCA INITIATOR 1.00E+00 CE-CW-NCCVDBCNFG DEBRIS CONFIG IN CAVITY NON-COOLABLE 9.90E-01

/CE-CW-VFTIMELONG TIME TO VESSEL FAILURE AFTER CORE RELOCATION VERY LONG 5.00E-02

/CE-CW-VSSLIMPNG VESSEL FAILS DUE TO DEBRIS IMPINGEMENT 9,99E-01 22 80.49 1.79E-09 CET_BEGP PDS FREQ I SMALL LOCA I SPRAYS + CACS + S/G COOLING 3.67E-06 CE-BP-CIS CONTAINMENT ISOLATION SUCCESS 9.95E-01

/CE-BP-CSP CONTAINMENT SPRAY FAILED EARLY 1.00E+00

/CE-BP-CSPFAILRIV ACCIDENT PROGRESSION FAILS CONTAINMENT SPRAY 9.50E-01

/CE-BP-CVFLOODSYS CAVITY FLOODING SYSTEM FAILED 9.84E-01 CE-BP-INVSSLH2 SUFFICIENT H2 PRODUCTION IN VESSEL TO FAIL CONTAINMENT 1.16E-03 CE-BP-PCSDEPRESS PCS DEPRESSURIZES PRIOR TO VESSEL FAILURE 9.50E-01 CE-BP-PCSRETEN SIGNIFICANT RETENTION OF PCS FISSION PRODUCTS 5.00E-01 CE-BP-SBLOCA SBLOCA INITIATOR 1.00E+00

/CE-BP-SECONDCOOL ALL S/G SECONDARY COOLING FAILED 1.00E+00 CE-BP-VSSLHTXFER HEAT TRANSFER FROM DEBRIS POOL PREDOMINANTLY UPWARD 9.50E-01

/CE-BP-VSSLIMPNG VESSEL FAILS DUE TO DEBRIS IMPINGEMENT 9.99E-01 23 81.13 1.61 E-09 CET_BEGP PDS FREQ I SMALL LOCA I SPRAYS + CACS + S/G COOLING 3.67E-06 CE-BP-CIS CONTAINMENT ISOLATION SUCCESS 9.95E-01

/CE-BP-CSP CONTAINMENT SPRAY FAILED EARLY 1.00E+00

/CE-BP-CSPFAIL ACCIDENT PROGRESSION FAILS CONTAINMENT SPRAYS LATE 9.00E-01

/CE-BP-CSPFAILRIV ACCIDENT PROGRESSION FAILS CONTAINMENT SPRAY 9.50E-01

/CE-BP-CVFLOODSYS CAVITY FLOODING SYSTEM FAILED 9.84E-01 CE-BP-INVSSLH2 SUFFICIENT H2 PRODUCTION IN VESSEL TO FAIL CONTAINMENT 1.16E-03 CE-BP-PCSDEPRESS PCS DEPRESSURIZES PRIOR TO VESSEL FAILURE 9.50E -01 B-13

LTR-PSA-08-01 April 4, 2008 Attachment B SAPHIRE SERF Change Set Data and Results Table B-1: PSAR2c Zero Maintenance, E-H (LERF) Only (Top 25 Outsets) 1 Cut No.

Total Prob./Freq Basic Event

_j Description ^-

Event Prob

/CE-BP-PCSRETEN SIGNIFICANT RETENTION OF PCS FISSION PRODUCTS 5.00E-01 CE-BP-SBLOCA SBLOCA INITIATOR 1.00E+00 CE-BP-VSSLHTXFER HEAT TRANSFER FROM DEBRIS POOL PREDOMINANTLY UPWARD 9.50E-01

/CE-BP-VSSLIMPNG VESSEL FAILS DUE TO DEBRIS IMPINGEMENT 9.99E-01 24 81.77 1.61E-09 CET_BEGP PDS FREQ I SMALL LOCA I SPRAYS + CACS + S/G COOLING 3.67E-06 CE-BP-CIS CONTAINMENT ISOLATION SUCCESS 9.95E-01

/CE-BP-CSP CONTAINMENT SPRAY FAILED EARLY 1.00E+00

/CE-BP-CSPFAIL ACCIDENT PROGRESSION FAILS CONTAINMENT SPRAYS LATE 9.00E-01

/CE-BP-CSPFAILRIV ACCIDENT PROGRESSION FAILS CONTAINMENT SPRAY 9.50E-01

/CE-BP-CVFLOODSYS CAVITY FLOODING SYSTEM FAILED 9.84E-01 CE-BP-INVSSLH2 SUFFICIENT H2 PRODUCTION IN VESSEL TO FAIL CONTAINMENT 1.16E-03 CE-BP-PCSDEPRESS PCS DEPRESSURIZES PRIOR TO VESSEL FAILURE 9.50E-01 CE-BP-PCSRETEN SIGNIFICANT RETENTION OF PCS FISSION PRODUCTS 5.00E-01 CE-BP-SBLOCA SBLOCA INITIATOR 1.00E+00 CE-BP-VSSLHTXFER HEAT TRANSFER FROM DEBRIS POOL PREDOMINANTLY UPWARD 9.50E-01

/CE-BP-VSSLIMPNG VESSEL FAILS DUE TO DEBRIS IMPINGEMENT 9.99E-01 25 82.4 1.59E-09 CET_A2EGR PDS FREQ I MLARGE LOCA

( CACS+SIRWT + S/G COOLING 3.00E-06

/CE-2R-CAC CONTAINMENT AIR COOLERS FAILED EARLY 1.00E+00

/CE-2R-CACFAIL ACCIDENT PROGRESSION FAILS CONTAINMENT AIR COOLERS LATE 9.00E-01

/CE-2R-CAVSMPDRNS CAVITY SUMP DRAINS OPEN (NO MOD) 1.00E+00 CE-2R-CIS CONTAINMENT ISOLATION SUCCESS 9.95E-01 CE-2R-CSP CONTAINMENT SPRAY FAILED EARLY 1.00E+00

/CE-2R-CSPRECOV CONTAINMENT SPRAYS RECOVERED 1.00E+00

/CE-2R-CSPRECRIV CONTAINMENT SPRAY RECOVERED FOR EX-VESSEL PROTECTION 1.00E+00

/CE-2R-FLNGFAIL CAVITY FLANGE FAILED 5.00E-01 CE-2R-INVSLSTEXP IN VESSEL STEAM EXPLOSION FAILS CONTAINMENT 5.00E-03 CE-2R-MBLOCA MEDIUM BREAK LOCA INITIATOR 1.00E+00

/CE-2R-NCCVDBCNFG DEBRIS CONFIG IN CAVITY NON-COOLABLE 2.50E-01

/CE-2R-PCSRETEN SIGNIFICANT RETENTION OF PCS FISSION PRODUCTS 1.00E+00

/CE-2R-SILATE SAFETY INJECTION AVAILABLE LATE 1.00E+00 CE-2R-VFTIMELONG TIME TO VESSEL FAILURE AFTER CORE RELOCATION VERY LONG 9.50E-01

/CE-2R-VSS LIMPNG VESSEL FAILS DUE TO DEBRIS IMPINGEMENT 9.99E-01 B-14

LTR-PSA-08-01 April 4, 2008 Attachment B SAPHIRE LERF Change Set Data and Results Table B-2: PSAR2c Zero Maintenance, EX-07 Failed, LOOP and Conditional LOOP Probabilities Changed, E-H (LERF ) Only (Top 25 Cutsets)

Cut No.

Prob./Freq Basic Event Description Total Event Prob.

1 25.69 7.43E-08 CETCEJW PDS FREQ I ISLOCA I NO CACS + NO SPRAYS + NO SIRWT + NO S/G COOLING 7.91E-08

/CE-CW-CAVSMPDRNS CAVITY SUMP DRAINS OPEN (NO MOD) 1.00E+00 CE-CW-CSP CONTAINMENT SPRAY FAILED EARLY 1.00E+00

/CE-CW-CSPRECRIV CONTAINMENT SPRAY RECOVERED FOR VESSEL PROTECTION 1.00E+00 CE-CW-ISLOCA INTERFACING SYSTEM LOCA INITIATOR 1.00E+00 CE-CW-NCCVDBCNFG DEBRIS CONFIG IN CAVITY NON-COOLABLE 9.90E-01 CE-CW-VFTIMELONG TIME TO VESSEL FAILURE AFTER CORE RELOCATION VERY LONG 9.50E-01 ICE-CW-VSSLIMPNG VESSEL FAILS DUE TO DEBRIS IMPINGEMENT 9.99E-01 2

29.36 1.06E-08 CET__A2EGR PDS FREQ I MLARGE LOCA I CACS+SIRWT + S/G COOLING 3.00E-06

/CE-2R-CAVSMPDRNS CAVITY SUMP DRAINS OPEN (NO MOD) 1.00E+00 CE-2R-CIS CONTAINMENT ISOLATION SUCCESS 9.95E-01 CE-2R-CSP CONTAINMENT SPRAY FAILED EARLY 1.00E+00

/CE-2R-CSPRECRIV CONTAINMENT SPRAY RECOVERED FOR EX-VESSEL PROTECTION 1.00E+00 CE-2R-INVSLSTEXP IN VESSEL STEAM EXPLOSION FAILS CONTAINMENT 5.00E-03 CE-2R-MBLOCA MEDIUM BREAK LOCA INITIATOR 1.00E+00 CE-2R-NCCVDBCNFG DEBRIS CONFIG IN CAVITY NON-COOLABLE 7.50E-01

/CE-2R-PCSRETEN SIGNIFICANT RETENTION OF PCS FISSION PRODUCTS 1.00E+00 CE-2R-VFTIMELONG TIME TO VESSEL FAILURE AFTER CORE RELOCATION VERY LONG 9.50E-01

/CE-2R-VSSLIMPNG VESSEL FAILS DUE TO DEBRIS IMPINGEMENT 9.99E-01 3

33.03 1.06E-08 CET__A2EGR PDS FREQ I MLARGE LOCA I CACS+SIRWT + S/G COOLING 3.00E-06

/CE-2R-CAVSMPDRNS CAVITY SUMP DRAINS OPEN (NO MOD) 1.00E+00 CE-2R-CIS CONTAINMENT ISOLATION SUCCESS 9.95E-01 CE-2R-CSP CONTAINMENT SPRAY FAILED EARLY 1.00E+00

/CE-2R-CSPRECRIV CONTAINMENT SPRAY RECOVERED FOR EX-VESSEL PROTECTION 1.00E+00 CE-2R-EXVSLSTEXP EX VESSEL STEAM EXPLOSION FAILS CONTAINMENT 5.00E-03 CE-2R-MBLOCA MEDIUM BREAK LOCA INITIATOR 1.00E+00 CE-2R-NCCVDBCNFG DEBRIS CONFIG IN CAVITY NON-COOLABLE 7.50E-01

/CE-2R-PCSRETEN SIGNIFICANT RETENTION OF PCS FISSION PRODUCTS 1.00E+00 CE-2R-VFTIMELONG TIME TO VESSEL FAILURE AFTER CORE RELOCATION VERY LONG 9.50E-01

/CE-2R-VSSLIMPNG VESSEL FAILS DUE TO DEBRIS IMPINGEMENT 9.99E-01 4

36.24 9.28E-09 CET_ZEGP PDS FREQ I ATWS I SPRAYS + CACS + S/G COOLING 5.36E-06 CE-ZP-CIS CONTAINMENT ISOLATION SUCCESS 9.95E-01

/CE-ZP-CSP CONTAINMENT SPRAY FAILED EARLY 1.00E+00

/CE-ZP-CSPFAILRIV ACCIDENT PROGRESSION FAILS CONTAINMENT SPRAY 9.50E-01 B-15

LTR-PSA-08-01 April 4, 2008 Attachment B SAPHIRE LERF Change Set Data and Results Tab le B-2 : PSAR2c Zero Maintenance, EX-07 Failed, LOOP and Conditional LOOP Proba bilities Changed, E-H (LERF ) Only (Top 25 Cutsets)

Cut No.

Total Prob -IFreq Basic Event Description Event Prob.

/CE-ZP-CVFLOODSYS CAVITY FLOODING SYSTEM FAILED 9.84E-01 CE-ZP-INVSSLH2 SUFFICIENT H2 PRODUCTION IN VESSEL TO FAIL CONTAINMENT 7.92E-03

/CE-ZP-MSLBICFRAC CORE MELT FREQUENCY FRACTION FOR MSLB INSIDE CONTAINMENT 1.00E+00

/CE-ZP-MSLBOCFRAC MAIN STEAM LINE BREAK OUTSIDE CONTAINMENT 1.00E+00 CE-ZP-PCSDEPRESS PCS DEPRESSURIZES PRIOR TO VESSEL FAILURE 9.50E-01 CE-ZP-PCSRETEN SIGNIFICANT RETENTION OF PCS FISSION PRODUCTS 5.50E-01 CE-ZP-PZSRVFTC PZR CODE SAFETY FAILS OPEN 4.75E-01

/CE-ZP-SECONDCOOL ALL S/G SECONDARY COOLING FAILED 1.00E+00

/CE-ZP-SGTUBEFAIL HEATING INDUCES S/G TUBE(S) FAILURE 9.98E-01 CE-ZP-TRANSIENT TURBINE TRIP INITIATOR 1.00E+00 CE-ZP-VSSLHTXFER HEAT TRANSFER FROM DEBRIS POOL PREDOMINANTLY UPWARD 9.50E-01

/CE-ZP-VSSLIMPNG VESSEL FAILS DUE TO DEBRIS IMPINGEMENT 9.99E-01 5

39.22 8.61 E-09 CET_ZEGP PDS FREQ I ATWS I SPRAYS + CACS + S/G COOLING 5.36E-06 CE-ZP-CIS CONTAINMENT ISOLATION SUCCESS 9.95E-01

/CE-ZP-CSP CONTAINMENT SPRAY FAILED EARLY 1.00E+00

/CE-ZP-CSPFAILRIV ACCIDENT PROGRESSION FAILS CONTAINMENT SPRAY 9.50E-01

/CE-ZP-CVFLOODSYS CAVITY FLOODING SYSTEM FAILED 9.84E-01 CE-ZP-HOTLEGFAIL HEATING INDUCES HOT LEG FAILURE 4.41E-01 CE-ZP-INVSSLH2 SUFFICIENT H2 PRODUCTION IN VESSEL TO FAIL CONTAINMENT 7.92E-03

/CE-ZP-MSLBICFRAC CORE MELT FREQUENCY FRACTION FOR MSLB INSIDE CONTAINMENT 1.00E+00

/CE-ZP-MSLBOCFRAC MAIN STEAM LINE BREAK OUTSIDE CONTAINMENT 1.00E+00 CE-ZP-PCSDEPRESS PCS DEPRESSURIZES PRIOR TO VESSEL FAILURE 9.50E-01 CE-ZP-PCSRETEN SIGNIFICANT RETENTION OF PCS FISSION PRODUCTS 5.50E-01

/CE-ZP-SECONDCOOL ALL S/G SECONDARY COOLING FAILED 1.00E+00

/CE-ZP-SGTUBEFAIL HEATING INDUCES SIG TUBE(S) FAILURE 9.98E-01 CE-ZP-TRANSIENT TURBINE TRIP INITIATOR 1.00E+00 CE-ZP-VSSLHTXFER HEAT TRANSFER FROM DEBRIS POOL PREDOMINANTLY UPWARD 9.50E-01

/CE-ZP-VSSLIMPNG VESSEL FAILS DUE TO DEBRIS IMPINGEMENT 9.99E-01 6

42.11

&.35E-09 CET_ZEGP PDS FREQ I ATWS I SPRAYS + CACS + SIG COOLING 5.36E-06 CE-ZP-CIS CONTAINMENT ISOLATION SUCCESS 9.95E-01

/CE-ZP-CSP CONTAINMENT SPRAY FAILED EARLY 1.00E+00

/CE-ZP-CSPFAIL ACCIDENT PROGRESSION FAILS CONTAINMENT SPRAYS LATE 9.00E-01 ICE-ZP-CSPFAILRIV ACCIDENT PROGRESSION FAILS CONTAINMENT SPRAY 9.50E-01

/CE-ZP-CVFLOODSYS CAVITY FLOODING SYSTEM FAILED 9.84E-01 B-16

LTR-PSA-08-01 April 4, 2008 Attachment B SAPHIRE LERF Change Set Data and Results a

e B -

A 2c Zero Mai ntenance, EX-07 Failed, LOOP and Conditional LOOP Probabilities Changed, E-H (LERF ) Only (Top 25 Cutsets)

Cut No.

Prob./Freq Basic Event Description Event Total f P

Prob.

44.79

7. 75E-09 47.45

7. 69E-09 CE-ZP-INVSSLH2 SUFFICIENT H2 PRODUCTION IN VESSEL TO FAIL CONTAINMENT

/CE-ZP-MSLBICFRAC CORE MELT FREQUENCY FRACTION FOR MSLB INSIDE CONTAINMENT

/CE-ZP-MSLBOCFRAC MAIN STEAM LINE BREAK OUTSIDE CONTAINMENT CE-ZP-PCSDEPRESS PCS DEPRESSURIZES PRIOR TO VESSEL FAILURE CE-ZP-PCSRETEN SIGNIFICANT RETENTION OF PCS FISSION PRODUCTS CE-ZP-PZSRVFTC PZR CODE SAFETY FAILS OPEN

/CE-ZP-SGTUBEFAIL HEATING INDUCES S/G TUBE(S) FAILURE CE-ZP-TRANSIENT TURBINE TRIP INITIATOR CE-ZP-VSSLHTXFER HEAT TRANSFER FROM DEBRIS POOL PREDOMINANTLY UPWARD

/CE-ZP-VSSLIMPNG VESSEL FAILS DUE TO DEBRIS IMPINGEMENT CET__ZEGP PDS FREQ I ATWS I SPRAYS + CACS + S/G COOLING CE-ZP-CIS CONTAINMENT ISOLATION SUCCESS

/CE-ZP-CSP CONTAINMENT SPRAY FAILED EARLY

/CE-ZP-CSPFAIL ACCIDENT PROGRESSION FAILS CONTAINMENT SPRAYS LATE

/CE-ZP-CSPFAILRIV ACCIDENT PROGRESSION FAILS CONTAINMENT SPRAY

/CE-ZP-CVFLOODSYS CAVITY FLOODING SYSTEM FAILED CE-ZP-HOTLEGFAIL HEATING INDUCES HOT LEG FAILURE CE-ZP-INVSSLH2 SUFFICIENT H2 PRODUCTION IN VESSEL TO FAIL CONTAINMENT

/CE-ZP-MSLBICFRAC CORE MELT FREQUENCY FRACTION FOR MSLB INSIDE CONTAINMENT

/CE-ZP-MSLBOCFRAC MAIN STEAM LINE BREAK OUTSIDE CONTAINMENT CE-ZP-PCSDEPRESS PCS DEPRESSURIZES PRIOR TO VESSEL FAILURE CE-ZP-PCSRETEN SIGNIFICANT RETENTION OF PCS FISSION PRODUCTS

/CE-ZP-SGTUBEFAIL HEATING INDUCES S/G TUBE(S) FAILURE CE-ZP-TRANSIENT TURBINE TRIP INITIATOR CE-ZP-VSSLHTXFER HEAT TRANSFER FROM DEBRIS POOL PREDOMINANTLY UPWARD

/CE-ZP-VSSLIMPNG VESSEL FAILS DUE TO DEBRIS IMPINGEMENT CETBEGP PDS FREQ I SMALL LOCA I SPRAYS + CACS + S/G COOLING CE-BP-CIS CONTAINMENT ISOLATION SUCCESS

/CE-BP-CSP CONTAINMENT SPRAY FAILED EARLY

/CE-BP-CSPFAILRIV ACCIDENT PROGRESSION FAILS CONTAINMENT SPRAY

/CE-BP-CVFLOODSYS CAVITY FLOODING SYSTEM FAILED CE-BP-EXVSLSTEXP EX VESSEL STEAM EXPLOSION FAILS CONTAINMENT CE-BP-PCSDEPRESS PCS DEPRESSURIZES PRIOR TO VESSEL FAILURE CE-BP-PCSRETEN SIGNIFICANT RETENTION OF PCS FISSION PRODUCTS 1.00E+00 1.00E+00 9.50E-01 5.50E-01 4.75E-01 9.98E-01 1.00E+00 9.50E-01 9.99E-01 5.36E-06 9.95E-01 1.00E+00 9.00E-01 9.50E-01 9.84E-01 4.41 E-01 7.92E-03 1.00E+00 1.00E+00 9.50E-01 5.50E-01 9.98E-01 1.00E+00 9.50E-01 9.99E-01 3.67E-06 9.95E-01 1.00E+00 9.50E-01 9.84E-01 5.00E-03 9,50E-01 5.00E-01 B-17

LTR-PSA-08-01 April 4, 2008 Attachment B SAPHIRE LERF Change Set Data and Results Table B-2 : PSAR2c Zero Maintenance, EX-07 Failed, LOOP and Conditional LOOP Probabilities Changed, E-H (LERF ) Only (Top 25 Cu tsets}

Cut No.

Total Prob./Freq Basic Event Description Event Prob.

CE-BP-SBLOCA SBLOCA INITIATOR 1.00E+00

/CE-BP-SECONDCOOL ALL S/G SECONDARY COOLING FAILED 1.00E+00 CE-BP-VSSLHTXFER HEAT TRANSFER FROM DEBRIS POOL PREDOMINANTLY UPWARD 9.50E-01

/CE-BP-VSSLIMPNG VESSEL FAILS DUE TO DEBRIS IMPINGEMENT 9.99E-01 9

49.84 6.92E-09 CET_BEGP PDS FREQ I SMALL LOCA

( SPRAYS + CACS + S/G COOLING 3.67E-06 CE-BP-CIS CONTAINMENT ISOLATION SUCCESS 9.95E-01

/CE-BP-CSP CONTAINMENT SPRAY FAILED EARLY 1.00E+00

/CE-BP-CSPFAIL ACCIDENT PROGRESSION FAILS CONTAINMENT SPRAYS LATE 9.00E-01

/CE-BP-CSPFAILRIV ACCIDENT PROGRESSION FAILS CONTAINMENT SPRAY 9.50E-01

/CE-BP-CVFLOODSYS CAVITY FLOODING SYSTEM FAILED 9.84E-01 CE-BP-EXVSLSTEXP EX VESSEL STEAM EXPLOSION FAILS CONTAINMENT 5.00E-03 CE-BP-PCSDEPRESS PCS DEPRESSURIZES PRIOR TO VESSEL FAILURE 9.50E-01

/CE-BP-PCSRETEN SIGNIFICANT RETENTION OF PCS FISSION PRODUCTS 5.00E-01 CE-BP-SBLOCA SBLOCA INITIATOR 1.00E+00 CE-BP-VSSLHTXFER HEAT TRANSFER FROM DEBRIS POOL PREDOMINANTLY UPWARD 9.50E-01

/CE-BP-VSSLIMPNG VESSEL FAILS DUE TO DEBRIS IMPINGEMENT 9.99E-01 10 52.23 6.92E-09 CET_BEGP PDS FREQ I SMALL LOCA I SPRAYS + CACS + S/G COOLING 3.67E-06 CE-BP-CIS CONTAINMENT ISOLATION SUCCESS 9.95E-01

/CE-BP-CSP CONTAINMENT SPRAY FAILED EARLY 1.00E+00

/CE-BP-CSPFAIL ACCIDENT PROGRESSION FAILS CONTAINMENT SPRAYS LATE 9.00E-01

/CE-BP-CSPFAILRIV ACCIDENT PROGRESSION FAILS CONTAINMENT SPRAY 9.50E-01

/CE-BP-CVFLOODSYS CAVITY FLOODING SYSTEM FAILED 9.84E-01 CE-BP-EXVSLSTEXP EX VESSEL STEAM EXPLOSION FAILS CONTAINMENT 5.00E-03 CE-BP-PCSDEPRESS PCS DEPRESSURIZES PRIOR TO VESSEL FAILURE 9.50E-01 CE-BP-PCSRETEN SIGNIFICANT RETENTION OF PCS FISSION PRODUCTS 5.00E-01 CE-BP-SBLOCA SBLOCA INITIATOR 1.00E+00 CE-BP-VSSLHTXFER HEAT TRANSFER FROM DEBRIS POOL PREDOMINANTLY UPWARD 9.50E-01

/CE-BP-VSSLIMPNG VESSEL FAILS DUE TO DEBRIS IMPINGEMENT 9.99E-01 11 54.59 6.83E-09 CET_ZEGP PDS FREQ I ATWS I SPRAYS + CACS + S/G COOLING 5.36E-06 CE-ZP-CIS CONTAINMENT ISOLATION SUCCESS 9.95E-01

/CE-ZP-CSP CONTAINMENT SPRAY FAILED EARLY 1.00E+00

/CE-ZP-CSPFAIL ACCIDENT PROGRESSION FAILS CONTAINMENT SPRAYS LATE 9.00E-01

/CE-ZP-CSPFAILRIV ACCIDENT PROGRESSION FAILS CONTAINMENT SPRAY 9.50E-01

/CE-ZP-CVFLOODSYS CAVITY FLOODING SYSTEM FAILED 9.84E-01 B-18

LTR-PSA-08-01 April 4, 2008 Attachment B SAPHIRE LERF Change Set Data and Results Ta ble B-2:

c Zero M aintenance, EX-07 Failed, LOOP and Conditional LOOP Probabilities Changed, E-H (LERF ) Only (Top 25 Cutse ts)

Cut No. T Prob./Freq Basic Event Description

^^

Event Total 12 13 56.78 58.81 6.34E-09 5.86E-09

/CE-ZP-MSLBICFRAC

/CE-ZP-MSLBOCFRAC CE-ZP-PCSDEPRESS

/CE-ZP-PCSRETEN CE-ZP-PZSRVFTC

/CE-ZP-SGTUBEFAIL CE-ZP-TRANSIENT CE-ZP-VSSLHTXFER

/CE-ZP-VSSLIMPNG CET_ZEGP CE-ZP-CIS

/CE-ZP-CSP

/CE-ZP-CSPFAIL

/CE-ZP-CSPFAILRIV

/CE-ZP-CVFLOODSYS CE-ZP-HOTLEGFAIL CE-ZP-INVSSLH2

/CE-ZP-MSLBICFRAC ICE-ZP-MSLBOCFRAC CE-ZP-PCSDEPRESS

/CE-ZP-PCSRETEN

/CE-ZP-SGTUBEFAIL CE-ZP-TRANSIENT CE-ZP-VSSLHTXFER

/CE-ZP-VSSLIMPNG CET_ZEGP CE-ZP-CIS ICE-ZP-CSP

/CE-ZP-CSPFAILRIV

/CE-ZP-CVFLOODSYS CE-ZP-EXVSLSTEXP

/CE-ZP-MSLBICFRAC

/CE-ZP-MSLBOCFRAC SUFFICIENT H2 PRODUCTION IN VESSEL TO FAIL CONTAINMENT CORE MELT FREQUENCY FRACTION FOR MSLB INSIDE CONTAINMENT MAIN STEAM LINE BREAK OUTSIDE CONTAINMENT PCS DEPRESSURIZES PRIOR TO VESSEL FAILURE SIGNIFICANT RETENTION OF PCS FISSION PRODUCTS PZR CODE SAFETY FAILS OPEN HEATING INDUCES SIG TUBE(S) FAILURE TURBINE TRIP INITIATOR HEAT TRANSFER FROM DEBRIS POOL PREDOMINANTLY UPWARD VESSEL FAILS DUE TO DEBRIS IMPINGEMENT PDS FREQ I ATWS I SPRAYS + CACS + S/G COOLING CONTAINMENT ISOLATION SUCCESS CONTAINMENT SPRAY FAILED EARLY ACCIDENT PROGRESSION FAILS CONTAINMENT SPRAYS LATE ACCIDENT PROGRESSION FAILS CONTAINMENT SPRAY CAVITY FLOODING SYSTEM FAILED HEATING INDUCES HOT LEG FAILURE SUFFICIENT H2 PRODUCTION IN VESSEL TO FAIL CONTAINMENT CORE MELT FREQUENCY FRACTION FOR MSLB INSIDE CONTAINMENT MAIN STEAM LINE BREAK OUTSIDE CONTAINMENT PCS DEPRESSURIZES PRIOR TO VESSEL FAILURE SIGNIFICANT RETENTION OF PCS FISSION PRODUCTS HEATING INDUCES S/G TUBE(S) FAILURE TURBINE TRIP INITIATOR HEAT TRANSFER FROM DEBRIS POOL PREDOMINANTLY UPWARD VESSEL FAILS DUE TO DEBRIS IMPINGEMENT PDS FREQ

( ATWS I SPRAYS + CACS + SIG COOLING CONTAINMENT ISOLATION SUCCESS CONTAINMENT SPRAY FAILED EARLY ACCIDENT PROGRESSION FAILS CONTAINMENT SPRAY CAVITY FLOODING SYSTEM FAILED EX VESSEL STEAM EXPLOSION FAILS CONTAINMENT CORE MELT FREQUENCY FRACTION FOR MSLB INSIDE CONTAINMENT MAIN STEAM LINE BREAK OUTSIDE CONTAINMENT Prob.

7.92E-03 1.00E+00 1.00E+00 9.50E-01 4.50E-01 4,75E-01 9.98E-01 1.00E+00 9.50E-01 9.99E-01 5.36E-06 9.95E-01 1.00E+00 9.00E-01 9.50E-01 9.84E-01 4.41E-01 7.92E-03 1.00E+00 1.00E+00 9.50E-01 4.50E-01 9.98E-01 1.00E+00 9.50E-01 9.99E-01 5.36E-06 9.95E-01 1.00E+00 9.50E-01 9.84E-01 5.00E-03 1.00E+00 1.00E+00 B-19

LTR-PSA-08-01 April 4, 2008 Attachment B SAPHIRE LERF Change Set Data and Results Table B-2: PSAR2c Zero Maintenance, EX-07 Failed, LOOP and Conditional LOOP Probabilities Changed, E-H (LERF ) Only (Top 25 Outsets)

Cut No.

Prob./Freq Basic Event Description 1

Event Total Prob.

CE-ZP-PCSDEPRESS PCS DEPRESSURIZES PRIOR TO VESSEL FAILURE 9.50E-01 CE-ZP-PCSRETEN SIGNIFICANT RETENTION OF PCS FISSION PRODUCTS 5.50E-01 CE-ZP-PZSRVFTC PZR CODE SAFETY FAILS OPEN 4.75E-01

/CE-ZP-SECONDCOOL ALL S/G SECONDARY COOLING FAILED 1.00E+00

/CE-ZP-SGTUBEFAIL HEATING INDUCES S/G TUBE(S) FAILURE 9.98E-01 CE-ZP-TRANSIENT TURBINE TRIP INITIATOR 1.00E+00 CE-ZP-VSSLHTXFER HEAT TRANSFER FROM DEBRIS POOL PREDOMINANTLY UPWARD 9.50E-01

/CE-ZP-VSSLIMPNG VESSEL FAILS DUE TO DEBRIS IMPINGEMENT 9.99E-01 14 60.69 5.44E-09 CET_ZEGP PDS FREQ I ATWS I SPRAYS + CACS + S/G COOLING 5.36E-06 CE-ZP-CIS CONTAINMENT ISOLATION SUCCESS 9.95E-01

/CE-ZP-CSP CONTAINMENT SPRAY FAILED EARLY 1.00E+00

/CE-ZP-CSPFAILRIV ACCIDENT PROGRESSION FAILS CONTAINMENT SPRAY 9.50E-01

/CE-ZP-CVFLOODSYS CAVITY FLOODING SYSTEM FAILED 9.84E-01 CE-ZP-EXVSLSTEXP EX VESSEL STEAM EXPLOSION FAILS CONTAINMENT 5.00E-03 CE-ZP-HOTLEGFAIL HEATING INDUCES HOT LEG FAILURE 4.41E-01

/CE-ZP-MSLBICFRAC CORE MELT FREQUENCY FRACTION FOR MSLB INSIDE CONTAINMENT 1.00E+00

/CE-ZP-MSLBOCFRAC MAIN STEAM LINE BREAK OUTSIDE CONTAINMENT 1.00E+00 CE-ZP-PCSDEPRESS PCS DEPRESSURIZES PRIOR TO VESSEL FAILURE 9.50E-01 CE-ZP-PCSRETEN SIGNIFICANT RETENTION OF PCS FISSION PRODUCTS 5.50E-01

/CE-ZP-SECONDCOOL ALL SIG SECONDARY COOLING FAILED 1.00E+00

/CE-ZP-SGTUBEFAIL HEATING INDUCES S/G TUBE(S) FAILURE 9.98E-01 CE-ZP-TRANSIENT TURBINE TRIP INITIATOR 1.00E+00 CE-ZP-VSSLHTXFER HEAT TRANSFER FROM DEBRIS POOL PREDOMINANTLY UPWARD 9.50E-01

/CE-ZP-VSSLIMPNG VESSEL FAILS DUE TO DEBRIS IMPINGEMENT 9.99E-01 15 62.51 5.27E-09 CET_ZEGP PDS FREQ I ATWS I SPRAYS + CACS + S/G COOLING 5.36E-06 CE-ZP-CIS CONTAINMENT ISOLATION SUCCESS 9.95E-01

/CE-ZP-CSP CONTAINMENT SPRAY FAILED EARLY 1.00E+00

/CE-ZP-CSPFAIL ACCIDENT PROGRESSION FAILS CONTAINMENT SPRAYS LATE 9.00E-01

/CE-ZP-CSPFAILRIV ACCIDENT PROGRESSION FAILS CONTAINMENT SPRAY 9.50E-01

/CE-ZP-CVFLOODSYS CAVITY FLOODING SYSTEM FAILED 9.84E-01 CE-ZP-EXVSLSTEXP EX VESSEL STEAM EXPLOSION FAILS CONTAINMENT 5.00E-03

/CE-ZP-MSLBICFRAC CORE MELT FREQUENCY FRACTION FOR MSLB INSIDE CONTAINMENT 1.00E+00

/CE-ZP-MSLBOCFRAC MAIN STEAM LINE BREAK OUTSIDE CONTAINMENT 1.00E+00 CE-ZP-PCSDEPRESS PCS DEPRESSURIZES PRIOR TO VESSEL FAILURE 9.50E-01 B-20

LTR-PSA-08-01 April 4, 2008 Attachment B SAPHIRE LERF Change Set Data and Results Tab le B-2 : PSAR2c Zero Maintenance, EX-07 Failed, LOOP and Conditional LOOP Proba bilities Changed, E-H (LERF) Only (Top 25 Cutsets)

Cut No.

Prob.IFreq Basic Event Total_U mm

^^

Description Event Prob.

CE-ZP-PCSRETEN SIGNIFICANT RETENTION OF PCS FISSION PRODUCTS 5.50E-01 CE-ZP-PZSRVFTC PZR CODE SAFETY FAILS OPEN 4.75E-01

/CE-ZP-SGTUBEFAIL HEATING INDUCES S/G TUBE(S) FAILURE 9.98E-01 CE-ZP-TRANSIENT TURBINE TRIP INITIATOR 1.00E+00 CE-ZP-VSSLHTXFER HEAT TRANSFER FROM DEBRIS POOL PREDOMINANTLY UPWARD 9.50E-01

/CE-ZP-VSSLIMPNG VESSEL FAILS DUE TO DEBRIS IMPINGEMENT 9.99E-01 16 64.2 4.89E-09 CET_ZEGP PDS FREQ I ATWS I SPRAYS + CACS + S/G COOLING 536E-06 CE-ZP-CIS CONTAINMENT ISOLATION SUCCESS 9.95E-01

/CE-ZP-CSP CONTAINMENT SPRAY FAILED EARLY 1.00E+00

/CE-ZP-CSPFAIL ACCIDENT PROGRESSION FAILS CONTAINMENT SPRAYS LATE 9.00E-01

/CE-ZP-CSPFAILRIV ACCIDENT PROGRESSION FAILS CONTAINMENT SPRAY 9.50E-01

/CE-ZP-CVFLOODSYS CAVITY FLOODING SYSTEM FAILED 9.84E-01 CE-ZP-EXVSLSTEXP EX VESSEL STEAM EXPLOSION FAILS CONTAINMENT 5.00E-03 CE-ZP-HOTLEGFAIL HEATING INDUCES HOT LEG FAILURE 4.41E-01

/CE-ZP-MSLBICFRAC CORE MELT FREQUENCY FRACTION FOR MSLB INSIDE CONTAINMENT 1.00E+00

/CE-ZP-MSLBOCFRAC MAIN STEAM LINE BREAK OUTSIDE CONTAINMENT 1.00E+00 CE-ZP-PCSDEPRESS PCS DEPRESSURIZES PRIOR TO VESSEL FAILURE 9.50E-01 CE-ZP-PCSRETEN SIGNIFICANT RETENTION OF PCS FISSION PRODUCTS 5.50E-01

/CE-ZP-SGTUBEFAIL HEATING INDUCES S/G TUBE(S) FAILURE 9.98E-01 CE-ZP-TRANSIENT TURBINE TRIP INITIATOR 1.00E+00 CE-ZP-VSSLHTXFER HEAT TRANSFER FROM DEBRIS POOL PREDOMINANTLY UPWARD 9.50E-01

/CE-ZP-VSSLIMPNG VESSEL FAILS DUE TO DEBRIS IMPINGEMENT 9.99E-01 17 65.69 4.31 E-09 CET_ZEGP PDS FREQ I ATWS I SPRAYS + CACS + SIG COOLING 5.36E-06 CE-ZP-CIS CONTAINMENT ISOLATION SUCCESS 9.95E-01

/CE-ZP-CSP CONTAINMENT SPRAY FAILED EARLY 1.00E+00

/CE-ZP-CSPFAIL ACCIDENT PROGRESSION FAILS CONTAINMENT SPRAYS LATE 9.00E-01

/CE-ZP-CSPFAILRIV ACCIDENT PROGRESSION FAILS CONTAINMENT SPRAY 9.50E-01

/CE-ZP-CVFLOODSYS CAVITY FLOODING SYSTEM FAILED 9.84E-01 CE-ZP-EXVSLSTEXP EX VESSEL STEAM EXPLOSION FAILS CONTAINMENT 5.00E-03

/CE-ZP-MSLBICFRAC CORE MELT FREQUENCY FRACTION FOR MSLB INSIDE CONTAINMENT 1.00E+00

/CE-ZP-MSLBOCFRAC MAIN STEAM LINE BREAK OUTSIDE CONTAINMENT 1.00E+00 CE-ZP-PCSDEPRESS PCS DEPRESSURIZES PRIOR TO VESSEL FAILURE 9.50E-01

/CE-ZP-PCSRETEN SIGNIFICANT RETENTION OF PCS FISSION PRODUCTS 4.50E-01 CE-ZP-PZSRVFTC PZR CODE SAFETY FAILS OPEN 4.75E-01 B-21

LTR-PSA-08-01 April 4, 2008 Attachment B SAPHIRE LERF Change Set Data and Results Table B-2: PSAR2c Zero Maintenance, EX-07 Failed, LOOP and Conditional LOOP Probabilities Changed, E-H (LERF) Only (Top 25 Cutsets)

Cut No.

Prob.JFreq Basic Event Description Event Total Prob.

/CE-ZP-SGTUBEFAIL HEATING INDUCES SIG TUBE(S) FAILURE 9.98E-01 CE-ZP-TRANSIENT TURBINE TRIP INITIATOR 1.00E+00 CE-ZP-VSSLHTXFER HEAT TRANSFER FROM DEBRIS POOL PREDOMINANTLY UPWARD 9.50E-01

/CE-ZP-VSSLIMPNG VESSEL FAILS DUE TO DEBRIS IMPINGEMENT 9.99E-01 18 67.07 4.00E-09 CET__ZEGP PDS FREQ

( ATWS I SPRAYS + CACS + S/G COOLING 5.36E-06 CE-ZP-CIS CONTAINMENT ISOLATION SUCCESS 9.95E-01

/CE-ZP-CSP CONTAINMENT SPRAY FAILED EARLY 1.00E+00

/CE-ZP-CSPFAIL ACCIDENT PROGRESSION FAILS CONTAINMENT SPRAYS LATE 9.00E-01

/CE-ZP-CSPFAILRIV ACCIDENT PROGRESSION FAILS CONTAINMENT SPRAY 9.50E-01

/CE-ZP-CVFLOODSYS CAVITY FLOODING SYSTEM FAILED 9.84E-01 CE-ZP-EXVSLSTEXP EX VESSEL STEAM EXPLOSION FAILS CONTAINMENT 5.00E-03 CE-ZP-HOTLEGFAIL HEATING INDUCES HOT LEG FAILURE 4.41E-01

/CE-ZP-MSLBICFRAC CORE MELT FREQUENCY FRACTION FOR MSLB INSIDE CONTAINMENT 1.00E+00

/CE-ZP-MSLBOCFRAC MAIN STEAM LINE BREAK OUTSIDE CONTAINMENT 1.00E+00 CE-ZP-PCSDEPRESS PCS DEPRESSURIZES PRIOR TO VESSEL FAILURE 9.50E-01

/CE-ZP-PCSRETEN SIGNIFICANT RETENTION OF PCS FISSION PRODUCTS 4.50E-01

/CE-ZP-SGTUBEFAIL HEATING INDUCES S/G TUBE(S) FAILURE 9.98E-01 CE-ZP-TRANSIENT TURBINE TRIP INITIATOR 1.00E+00 CE-ZP-VSSLHTXFER HEAT TRANSFER FROM DEBRIS POOL PREDOMINANTLY UPWARD 9.50E-01 ICE-ZP-VSSLIMPNG VESSEL FAILS DUE TO DEBRIS IMPINGEMENT 9.99E-01 19 6835 3.72E-09 CET _CEJW PDS FREQ I ISLOCA I NO CACS + NO SPRAYS + NO SIRWT + NO S/G COOLING 7.91 E-08

/CE-CW-CAVSMPDRNS CAVITY SUMP DRAINS OPEN (NO MOD) 1.00E+00 CE-CW-ISLOCA INTERFACING SYSTEM LOCA INITIATOR 1.00E+00 CE-CW-NCCVDBCNFG DEBRIS CONFIG IN CAVITY NON-COOLABLE 9.90E-01 CE-CW-VFTIMELONG TIME TO VESSEL FAILURE AFTER CORE RELOCATION VERY LONG 9.50E-01

/CE-CW-VSSLHTXFER HEAT TRANSFER FROM DEBRIS POOL PREDOMINANTLY UPWARD 5.00E-02

/CE-CW-VSSLIMPNG VESSEL FAILS DUE TO DEBRIS IMPINGEMENT 9.99E-01 20 69.17 2.38E-09 CET_BEGR PDS FREQ I SMALL LOCA I CACS+SIRWT + S/G COOLING 2.56E-06

/CE-BR-CAVSMPDRNS CAVITY SUMP DRAINS OPEN (NO MOD) 1.00E+00 CE-BR-CIS CONTAINMENT ISOLATION SUCCESS 9.95E-01 CE-BR-CSP CONTAINMENT SPRAY FAILED EARLY 1.00E+00

/CE-BR-CSPRECRIV CONTAINMENT SPRAY RECOVERED FOR EX-VESSEL PROTECTION 1.00E+00 CE-BR-EXVSLSTEXP EX VESSEL STEAM EXPLOSION FAILS CONTAINMENT 5.00E-03 CE-BR-NCCVDBCNFG DEBRIS CONFIG IN CAVITY NON-COOLABLE 7.50E-01 B-22

LTR-PSA-08-01 April 4, 2008 Attachment B SAPHIRE LERF Change Set Data and Results Table B-2: PSAR2c Zero Maintenance, EX-07 Failed, LOOP and Cond itional LOOP Probabilities Changed, E-H (LERF ) Only (Top 25 Cutsets)

Cut No.

ProbJFreq Basic Event Description Event Total Prob.

/CE-BR-PCSRETEN SIGNIFICANT RETENTION OF PCS FISSION PRODUCTS 5.00E-01 CE-BR-SBLOCA SBLOCA INITIATOR 1.00E+00 CE-BR-VFTIMELONG TIME TO VESSEL FAILURE AFTER CORE RELOCATION VERY LONG 5.00E-01

/CE-BR-VSSLIMPNG VESSEL FAILS DUE TO DEBRIS IMPINGEMENT 9.99E-01 21 69.87 2.04E-09 CET_TEJP PDS FREQ I TRANSIENT I SPRAYS + CACS + NO S/G COOLING 1.70E-06 CE-TP-CIS CONTAINMENT ISOLATION SUCCESS 9.95E-01

/CE-TP-CSP CONTAINMENT SPRAY FAILED EARLY 1.00E+00

/CE-TP-CSPFAIL ACCIDENT PROGRESSION FAILS CONTAINMENT SPRAYS LATE 9.00E-01

/CE-TP-CSPFAILRIV ACCIDENT PROGRESSION FAILS CONTAINMENT SPRAY 9.50E-01

/CE-TP-CVFLOODSYS CAVITY FLOODING SYSTEM FAILED 9.84E-01 CE-TP-INVSSLH2 SUFFICIENT H2 PRODUCTION IN VESSEL TO FAIL CONTAINMENT 7.92E-03

/CE-TP-MSLBICFRAC CORE MELT FREQUENCY FRACTION FOR MSLB INSIDE CONTAINMENT 1.00E+00

/CE-TP-MSLBOCFRAC MAIN STEAM LINE BREAK OUTSIDE CONTAINMENT 1.00E+00 CE-TP-PCSDEPRESS PCS DEPRESSURIZES PRIOR TO VESSEL FAILURE 7.30E-01 CE-TP-PCSRETEN SIGNIFICANT RETENTION OF PCS FISSION PRODUCTS 5.50E-01 CE-TP-PZSRVFTC PZR CODE SAFETY FAILS OPEN 4.75E-01

/CE-TP-SGTUBEFAIL HEATING INDUCES S/G TUBE(S) FAILURE 9.98E-01 CE-TP-TRANSIENT TURBINE TRIP INITIATOR 1.00E+00 CE-TP-VSSLHTXFER HEAT TRANSFER FROM DEBRIS POOL PREDOMINANTLY UPWARD 9.50E-01

/CE-TP-VSSLIMPNG VESSEL FAILS DUE TO DEBRIS IMPINGEMENT 9.99E-01 22 70.55 1.96E-09 CET_CEJW PDS FREQ I ISLOCA I NO CACS + NO SPRAYS + NO SIRWT + NO S/G COOLING 7.91E-08

/CE-CW-CAVFLRFAIL CAVITY FLOOR CATASTROPHIC FAILURE EARLY 1.00E+00

/CE-CW-CAVSMPDRNS CAVITY SUMP DRAINS OPEN (NO MOD) 1.00E+00 CE-CW-CRDBAFTBD MOST OF THE CORE DEBRIS EXITS THE VESSEL AFTER BLOWDOWN 5.00E-01 CE-CW-CSP CONTAINMENT SPRAY FAILED EARLY 1.00E+00

/CE-CW-CSPRECRIV CONTAINMENT SPRAY RECOVERED FOR VESSEL PROTECTION 1.00E+00 CE-CW-ISLOCA INTERFACING SYSTEM LOCA INITIATOR 1.00E+00 CE-CW-NCCVDBCNFG DEBRIS CONFIG IN CAVITY NON-COOLABLE 9.90E-01

/CE-CW-VFTIMELONG TIME TO VESSEL FAILURE AFTER CORE RELOCATION VERY LONG 5.00E-02

/CE-CW-VSSLIMPNG VESSEL FAILS DUE TO DEBRIS IMPINGEMENT 9.99E-01 23 71.2 1.89E-09 CET_TEJP PDS FREQ I TRANSIENT I SPRAYS + CACS + NO S/G COOLING 1.70E-06 CE-TP-CIS CONTAINMENT ISOLATION SUCCESS 9.95E-01

/CE-TP-CSP CONTAINMENT SPRAY FAILED EARLY 1.00E+00

/CE-TP-CSPFAIL ACCIDENT PROGRESSION FAILS CONTAINMENT SPRAYS LATE 9.00E-01 B-23

LTR-PSA-08-01 April 4, 2008 Attachment B SAPHIRE LERF Change Set Data and Results Table B-2: PSAR2c Zero Mai ntenance, EX-07 Failed, LOOP and Conditional LOOP Probabilities Changed, E-H (LERF ) Only (To p 25 Cutsets)

Cut No.

Prob.[Freq Basic Event Description Event Total Prob.

24 25 71.82 1.79E-09 72.4 1.67E-09

/CE-TP-CSPFAILRIV

/CE-TP-CVFLOODSYS CE-TP-HOTLEGFAIL CE-TP-INVSSLH2 ICE-TP-MSLBICFRAC

/CE-TP-MSLBOCFRAC CE-TP-PCSDEPRESS CE-TP-PCSRETEN

/CE-TP-SGTUBEFAIL CE-TP-TRANSIENT CE-TP-VSSLHTXFER

/CE-TP-VSSLIMPNG CET_BEGP CE-BP-CIS

/CE-BP-CSP ICE-BP-CSPFAILRIV

/CE-BP-CVFLOODSYS CE-BP-INVSSLH2 CE-BP-PCSDEPRESS CE-BP-PCSRETEN CE-BP-SBLOCA

/CE-BP-SECONDCOOL CE-BP-VSSLHTXFER

/CE-BP-VSSLIMPNG CET_TEJP CE-TP-CIS

/CE-TP-CSP

/CE-TP-CSPFAIL

/CE-TP-CSPFAILRIV

/CE-TP-CVFLOODSYS CE-TP-INVSSLH2

/CE-TP-MSLBICFRAC

/CE-TP-MSLBOCFRAC CE-TP-PCSDEPRESS ACCIDENT PROGRESSION FAILS CONTAINMENT SPRAY CAVITY FLOODING SYSTEM FAILED HEATING INDUCES HOT LEG FAILURE SUFFICIENT H2 PRODUCTION IN VESSEL TO FAIL CONTAINMENT CORE MELT FREQUENCY FRACTION FOR MSLB INSIDE CONTAINMENT MAIN STEAM LINE BREAK OUTSIDE CONTAINMENT PCS DEPRESSURIZES PRIOR TO VESSEL FAILURE SIGNIFICANT RETENTION OF PCS FISSION PRODUCTS HEATING INDUCES S/G TUBE(S) FAILURE TURBINE TRIP INITIATOR HEAT TRANSFER FROM DEBRIS POOL PREDOMINANTLY UPWARD VESSEL FAILS DUE TO DEBRIS IMPINGEMENT PDS FREQ I SMALL LOCA

( SPRAYS + CACS + S/G COOLING CONTAINMENT ISOLATION SUCCESS CONTAINMENT SPRAY FAILED EARLY ACCIDENT PROGRESSION FAILS CONTAINMENT SPRAY CAVITY FLOODING SYSTEM FAILED SUFFICIENT H2 PRODUCTION IN VESSEL TO FAIL CONTAINMENT PCS DEPRESSURIZES PRIOR TO VESSEL FAILURE SIGNIFICANT RETENTION OF PCS FISSION PRODUCTS SBLOCA INITIATOR ALL S/G SECONDARY COOLING FAILED HEAT TRANSFER FROM DEBRIS POOL PREDOMINANTLY UPWARD VESSEL FAILS DUE TO DEBRIS IMPINGEMENT PDS FREQ I TRANSIENT I SPRAYS + CACS + NO S/G COOLING CONTAINMENT ISOLATION SUCCESS CONTAINMENT SPRAY FAILED EARLY ACCIDENT PROGRESSION FAILS CONTAINMENT SPRAYS LATE ACCIDENT PROGRESSION FAILS CONTAINMENT SPRAY CAVITY FLOODING SYSTEM FAILED SUFFICIENT H2 PRODUCTION IN VESSEL TO FAIL CONTAINMENT CORE MELT FREQUENCY FRACTION FOR MSLB INSIDE CONTAINMENT MAIN STEAM LINE BREAK OUTSIDE CONTAINMENT PCS DEPRESSURIZES PRIOR TO VESSEL FAILURE 9.84E-01 4.41E-01 7.92E-03 1.00E+00 1.00E+00 7.30E-01 5.50E-01 9.98E-01 1.00E+00 9.50E-01 9.99E-01 3.67E-06 9.95E-01 1.00E+00 9.50E-01 9.84E-01 1.16E-03 9.50E-01 5.00E-01 1.00E+00 1.00E+00 9.50E-01 9.99E-01 1.70E-06 9.95E-01 1.00E+00 9.00E-01 9.50E-01 9.84E-01 7.92E-03 1.00E+00 1.00E+00 7.30E-01 B-24

LTR-PSA-08-01 April 4, 2008 Attachment B SAPHIRE LERF Change Set Data and Results Table B-2 : PSAR2c Zero Maintenance, EX-07 Failed, LOOP and Conditional LOOP Probabilities Changed, E-H (LERF ) Only (Top 25 Cutsets)

Cut No.

°/n Prob.IFreq Basic Event Description Event Tota l-F I

Prob.

/CE-TP-PCSRETEN SIGNIFICANT RETENTION OF PCS FISSION PRODUCTS 4.50E-01 CE-TP-PZSRVFTC PZR CODE SAFETY FAILS OPEN 4.75E-01

/CE-TP-SGTUBEFAIL HEATING INDUCES SIG TUBE(S) FAILURE 9.98E-01 CE-TP-TRANSIENT TURBINE TRIP INITIATOR 1.00E+00 CE-TP-VSSLHTXFER HEAT TRANSFER FROM DEBRIS POOL PREDOMINANTLY UPWARD 9.50E-01 ICE-TP-VSSLIMPN G VESSEL FAILS DUE TO DEBRIS IMPINGEMENT 9.99E-01 B-25

LTR-PSA-08-01 April 4, 2008 Attachment B SAPHIRE LERF Change Set Data and Results Table B-3: Comparison of Tables B-1 and B-2 (Top 100 Cutsets)

EX-07 OOS, LOOP IE and Change in 7 Cut No.

% Total

% Cut Set Prob./Frequency Initiator Initiator Conditional LOOP Frequency Probability Increase (Table B-2 Sequence = Y}

Y mm 1

25.69 25.69 7.43E-08 IE->CET CEJW ISLOCA 1

29.42 29.42 7.43E-08 IE->CET CEJW Y

2 29.36 3.67 1.06E-08 IE->CET_A2EGR Medium Large LOCA Y

3 33.03 3.67 1.06E-08 IE->CET_A2EGR Medium Large LOCA 2

33.62 4.2 1.06E-08 I E->CETA2EGR 3

37.82 4.2 1.06E-08 IE->CET A2EGR Y

Increase 4

36.24 3.21 9.28E-09 IE->CET_ZEGP ATWS 4

41,47 3.65 9.21E-09 IE->CET ZEGP Y

Increase 5

39.22 2.98 8.61E-09 IE->CET ZEGP ATWS 5

44.86 3.39 8.55E-09 IE->CET^ZEGP Y

Increase 6

42.11 2.89 8.35E-09 lE->CET, ZEGP ATWS 6

48.14 3.28 8.29E-09 IE->CET ZEGP Y

Increase 7

4419 2.68 7.75E-09 IE->GET ZEGP ATWS 7

51.19 3.05 7.70E-09 IE->CET__ZEGP Y

8 47.45 2.66 7.69E-09 IE->CET BEGP Small Break LOCA 8

54.24 3.05 7.69E-09 IE->CET BEGP Y

9 49.84 2.39 6.92E-09 IE->CET BEGP Small Break LOCA Y

10 52.23 2.39 6.92E-09 IE->CET BEGP Small Break LOCA 9

56.98 2.74 6.92E-09 IE->CET BEGP 10 59.72 2.74 6.92E-09 IE->CET BEGP Y

Increase 11 54.59 2.36 6.53E-09 IE->CET,-ZEGP ATWS 11 62.41 2.69 6.78E-09 I E->CETZEGP Y

Increase 12 56.78 219 6.34E-09

!E->CET.TZEGP ATWS 12 64.9 2.49 6.30E-09 IE->CET ZEGP Y

Increase 13 58.81 2.03 5.86E-09 IE->CET ZEGP ATWS 13 67.2 2.3 5.82E-09 IE->CET^ZEGP Y

Increase 14 60.69 1.88 5.44E-09 IE->CET_ZEGP ATWS 14 69.34 2.14

5. 40E-09 IE->CET ZEGP B-26

QTR-PSA-08-01 April 4, 2008 Attachment B SAPHIRE SERF Change Set Data and Results Table B-3: Comparison of Tables B-1 and B-2 (Top 100 Cutsets)

EX-07 OOS, LOOP IE and Change in Cut No.

% Total

% Cut Set Prob./Frequency Initiator Initiator Conditional LOOP Frequency Probability Increase Table B -2 Sequence = Y)

Y Increase 15 62.51 1,82 5.27E-09 IE->CET_ZEGP ATWS 15 71.41 2.07 5.23E-09 IE->CET ZEGP Y

Increase 16 64.2 1.69 4.89E-09 IE->CET_ZEGP ATWS 16 7133 1.92 4.86E-09 IE->CETZEGP Y

Increase 17 65.69 1.49 4.31E-09 IE->CET_ZEGP ATWS 17 75.03 1.7 4.28E-09 IE->CET ZEGP Y

Increase 18 67.07 1.38 4.00E-09 IE->CET ZEGP

^

ATWS 18 76.6 1.57 3.98E-09 IE->CET ZEGP Y

19 68.35 1.28 3.72E-09 IE->CET CEJW ISLOCA 19 78.07 1.47 3.72E-09 IE->CET CEJW Y

20 69.17 0.82 2.38E-09 IE->CET BEGR ISLOCA 20 79.01 0.94 2.38E-09 IE->CET BEGR Y

Increase 21 69.87 0,7 2.04E-09 IE->CETTEJP ATWS Y

22 70.55 0.68 1.96E-09 IE->CET_CEJW Small Break LOCA 21 79.78 0.77 1.96E-09 IE->CETCEJW Y

Increase 23 71.2 0.65 1.89E-09 IE->CET TEJP Transient Y

24 71.82 0.62 1.79E-09 IE->CET1BEGP Small Break LOCA 22 80.49 0.71 1.79E-09 IE->CET BEGP Y

Increase 25 72.4 0.58 1.67E-09 IE->CET_TEJP Transient Y

26 72.96 0.56 1.61 E-09 IE->CET BEGP Small Break LOCA Y

27 73.52 0.56 1.61E-09

[E->CET_BEGP Small Break LOCA 23 81.13 0.64 1.61 E-09 IE->CET BEGP 24 81.77 0.64 1.61 E-09 IE->CET BEGP Y

28 74.07 0.55 1.59E-09 IE->CET_A2EGR Medium Large LOCA Y

29 74.62 0.55 1.59E-09 IE->CET_A2EGR Medium Large LOCA Y

30 75.17 0.55 1.59E-09 IE->CET_A2EGR Medium Large LOCA Y

31 75.72 0.55 1.59E-09 IE->CET_A2EGR Medium Large LOCA 25 82.4 0.63 1.59E-09 IE->CET A2EGR 26 83.03 0.63 1.59E-09 IE->CET_A2EGR B-27

LT R-PSA-08-01 April 4, 2008 Attachment B SAPHIRE SERF Change Set Data and Results Table B-3: Comparison of Tables B-1 and B-2 (Top 100 Cutsets)

EX-07 OOS, LOOP lE and Change in Cut No.

% Total

% Cut Set Prob./Frequency Initiator Initiator Conditional LOOP Frequency Probability Increase (Table B-2 Sequence = Y 27 83.66 0.63 1.59E-09 IE->CET A2EGR 28 84.29 0.63 1.59E-09 IE->CET A2EGR Y

32 76.27 0.55 1.59E-09 IE->CET BEGR Small Break LOCA 29 84.92 0.63 1.59E-09 IE->CET BEGR Y

Increase 33 76,8 0.53 1,55E-09 IE->CET TEJP Transient Y

34 77.32 0.52 1.51E-09 IE->CET BEGR Small Break LOCA 30 85.52 0.6 1.51 E-09 IE->CET BEGR Y

35 77.82 0.5 1.45E-09 IE->CET_A2EGP Small Break LOCA Y

36 78.32 0.5 1.45E-09 IE->CET_A2EGP Small Break LOCA 31 86.09 0.57 1.45E-09 IE->CET A2EGP 32 86.66 0.57 1.45E-09 IE->CET A2EGP Y

Increase 37 78,76 0.44 1.29E-09 IE->CET_TEJP Transient V

38 79.18 0.42 1.23E-09 IE->CET CEJW ISLOCA 33 87.15 0.49 1.23E-09 IE->CET CEJW Y

Increase 39 79.59 0.41 1.19E-09 IE->CET TEJP Transient Y

40 80 0.41 1.19E-09 IE->CET^BEGR Small Break LOCA 34 87.62 0.47 1.19E-09 I E->CETBEGR Y

41 80.39 0.39 1.13E-09 IE->CET_A2EGR Medium Large LOCA 35 88.07 0.45 1.13E-09 IE->CET A2EGR Y

Increase 42 8035 0.36 1.05E-09 IE->CET TEJP Transient V

43 81.1 0.35 1.01E-09 IE->CET BEGV Small Break LOCA 36 88.47 0.4 1.00E-09 IE->CET BEGV Y

Increase 44 81.45 0.35 9.98E-10 IE->CET_TEJW Transient V

Increase 45 81.8 0.35 9.98E-10 IE->CETTEJW Transient V

46 82.14 0.34 9.86E-10 IE->CET_CEJW ISLOCA 37 88.86 0.39 9.86E-10 IE->CET CEJW Y

Increase 47 82.48 0.34 9.77E-10 IE->CET, TEJP Transient Y

Increase 48 82.81 0.33 9.48E-10 I->CPT TEJW Transient Y

Increase 49 83,14 0,33 9.48E-10 IE->CET TEJW Transient B-28

LTR-PSA-08-01 April 4, 2008 Attachment B SAPHIRE LERF Change Set Data and Results Table B-3: Comparison of Tables B-1 and B-2 (Top 100 Cutsets)

EX-07 OOS, LOOP IE and Change in Cut No.

% Total

% Cut Set Prob./Frequency Initiator Initiator Conditional LOOP Frequency Probability Increase (Table B-2 Sequence = Y)

Y 50 83.46 0.32 9.37E-10 IE->CET CEJW T

ISLOCA 38 89.23 0.37 9.37E-10 IE->CET CEJW Y

Increase 51 8175 0.29 8.46E-10 IE->CET4TEJQ Transient Y

52 84.03 0.28 7.97E-10 IE->CETBEGR Small Break LOCA 39 89.55 0.32 7.97E-10 IE->CETBEGR Y

53 84.3 0.27 7.93E-10 IE->CET BEGR Small Break LOCA Y

54 84.57 0.27 7.93E-10 IE->CET_BEGR Small Break LOCA 40 89.86 0.31 7.93E-10 IE->CET BEGR 41 90.17 0.31 7.93E-10 IE->CET BEGR Y

Increase 55 84.84 0.27 7.85E-10 IE->CET_TEJQ Transient Y

56 85.11 0.27 7.69E-10 IE->CET BEGP Small Break LOCA 42 90.47 0.3 7.69E-10 IE->CETBEGP Y

Increase 57 85.37 0.26 7.59E-10 IE->CET_ZEGP ATWS Y

58 85.63 0.26 7.57E-10 IE->CET BEGR Small Break LOCA 43 90.77 0.3 7.57E-10 IE->CET BEGR 44 91.07 0.3 7.54E-10 IE->CET ZEGP ATWS Y

Increase 69 85,89 0.26 7.54E-10 IE->CET_BEGR Small Break LOCA Y

Increase 60 86.15 0.26 7.54E-10 IE->CET-BEGR Small Break LOCA 45 91.37 0.3 7.53E-10 IE->CET BEGR 46 91.67 0.3 7.53E-10 IE->CET BEGR Y

61 86.41 0.26 7.50E-10 IE->CET CEJW ISLOCA 47 91.97 0.3 7.50E-10 IE->CET_CEJW Y

62 86.66 0.25 7.30E-10 IE->CET TEJW Transient Y

63 86.91 0.25 7.30E-10 IE->CET TEJW Transient Y

Increase 64 87.15 0.24 7.05E-10 IE->CET_ZEGP ATWS 48 92.25 0.28 7.00E-10 IE->CET ZEGP Y

65 87.39 0.24 6.93E-10

[E->CET TEJW Transient Y

66 87.63 0.24 6.93E-10 IE->CETTEJW Transient Y

Increase 67 87.87 0.24 6.92E-10 I E->CET, TEJQ Tran s ient B-29

QTR-PSA-08-01 April 4, 2008 Attachment B SAPHIRE SERF Change Set Data and Results EX-7 OOS, LOOP IE and Conditional LOOP Probability Increase Table B-Sequence = Y^

^

Change in Frequency Table B-3: Comparison of Tables B-1 and B-2 (Top 100 Cutsets)

Cut No.

% Total

%a Cut Set Prb./Frequency Initiator Initiator Y

68 88.1 0.23 6.78E-10 IE->CET TEJW Transient Y

69 88.33 0.23 6.78E-10 IE->CET TEJW Transient Y

Increase 70 88.56 0.23 611E-10 IE->CET BEGV Small Break LOCA 49 92.51 0.26 6.66E-10 I E->CETBEGV Y

71 88.78 0.22 6.44E-10 IE->CET TEJW Transient Y

72 89 0.22 6.44E-10 IE->CET TEJW Transient Y

Increase 73 89.22 0.22 6.42E-10 IE->CETJEJQ Transient Y

Increase 74 89.44 0.22 6.37E-10 IE->CET BEGV Small Break LOCA 50 92.76 0.25 6.33E-10 IE->CET_BEGV Y

75 89.65 0.21 5.96E-10 IE->CET TEJW Transient Y

76 89.86 0.21 5.96E-10 IE->CET TEJW Transient Y

77 90.06 0.2 5.66E-10 IE->CET TEJW Transient Y

78 90.26 0.2 5.66E-10 IE->CET TEJW Transient Y

Increase 79 90.45 0,19 5.53E-10 IE->CET_BEGR Small Break LOCA 51 92.98 0.22 5.52E-10 IE->CET BEGR Y

Increase 80 90.63 0.18 5.34E-10 IE->CET_TEJQ Transient Y

81 90.81 0.18 5.31E-10 IE->CET_A2EGR Medium Large LOCA Y

82 90.99 0.18 5.31E-10 IE->CET_A2EGR Medium Large LOCA 52 93.19 0.21 5.31E-10 IE->CET A2EGR 53 93.4 0.21 5.31E-10 IE->CET A2EGR Y

Increase 83 91,16 0.17 5.02E-10 IE->CETTTEJW Transient Y

Increase 84 91.33 0,17 5.01E-10 IE->CETTBEGV Small Break LOCA Y

Increase 85 91.5 0.17 4.99E-10 IE->CET-TEJW Transient 54 93.6 0.2 4.98E-10 IE->CET BEGV Y

Increase 86 91.67 0.17 4.96E-10 IE->CET^_TEJQ Transient Y

Increase 87 91.84 0.17 4.88E-10 IE->CET ZEGP ATWS Y

88 92.01 0.17 4.86E-10 IE->CET_BEGS Small Break LOCA 55 93.79 0.19 4.86E-10 IE-CET BEGS 56 93.98 0.19 4.85E-10 IE->CET_ZEGP B-30

LTR-PSA-08-01 April 4, 2008 Attachment B SAPHIRE LERF Change Set Data and Results Table B-3: Comparison of Tables B-1 and B-2 (Top 100 Cutsets)

EX-07 OOS, LOOP IE and Change in Cut No.

% Total

% Cut Set Prob./Frequency Initiator Initiator Conditional LOOP Frequency Probability Increase (Table B-2 Sequence = Y)

Y increase 9-92.18 0A7

-4.79E-10 iE->CET-ZEGP ATWS Y

Increase 90 92.34 0.16 4,77E-10 IE->CETTEJW Transient 57 94.17 0.19 4.76E-10 IE->CET ZEGP Y

Increase 91 92.5 0.16 4.74E-10 IE->CET, TEJW Transient Y

Increase 92 92.65 0.15 4.45E-10 IE->CET ZEGP ATWS 58 94.34 0.17 4.42E-10 IE->CET ZEGP Y

Increase 93 92.8 0.15 4.39E-10 IE->CET ZEGP ATWS Y

Increase 94 92.95 0.15 4.37E-10 IE->CET TEJQ Transient 59 94.51 0.17 4.36E-10 IE->CET ZEGP Y

Increase 95 93.09 0.14 4.06E-10 IE->CET_TEJQ Transient Y

96 93.22 0.13 3.72E-10 IE->CET_A2EGR Medium Large LOCA 60 94.66 0.15 172E-10 IE->CET A2EGR Y

Increase 97 93.35 0.13 3.67E-10 IE->CET-TEJW Transient Y

Increase 98 93.48 0.13 3.65E-10 IE->CET_TEJW Transient Y

Increase 99 93.6 0.12 3.60E-10 IE->CET ZEGP ATWS Y

100 93.72 0.12 3.57E-1 0 IE->CET BEGR Small Break LOCA B-31

Attachment C (pg Cl)

Applied Reliabil ity Engineering, inc PA07-05-01 April 4, 2008 Mr. Brian Brogan Palisades Nuclear Power Plant 27780 Blue Star Memorial Hwy Covert, Ml 49043 Re: Review of Tech Letter 08-01 (Evaluation of Safeguards XFMR (EX-07) Anomalies Associated with an Oil Pressure Relay Actuation)

Dear Brian:

A review of Technical Letter 08-01 has been performed with the following findings:

There are two potential sources of increase in risk associated with removal of the safeguards transformer from service; increase in the frequency of a loss of offsite power as an initiating event and increase in the potential for loss of offsite power following other internal or external initiators.

Both sources of risk are addressed in the Technical Letter.

I concur with key assumptions input to the quantification of the Palisades internal events PRA.

Failing the safeguards transformer and the F Bus in the PRA appropriately represents the removal of the safeguards transformer from service.

Increasing the loss of offsite power frequency by a factor of two in the PRA is similar to generating a Jeffrey's non-informative prior for loss of the startup transformer over the life of the plant and assuming it represented an additional source of plant centered loss of offsite power with the safeguards transformer removed from service.

Increasing the transient induced loss of offsite power by a factor of 10 is significantly greater than the expected loss of offsite power increase noted above and is considered to be conservative.

I repeated the internal events accident sequence quantification under the above assumptions and produced essentially identical results as presented in the Technical Letter.

For the fire PRA, the analysis recognizes that a fire leading directly to loss of offsite power conditions may be more likely given removal of the safeguards transformer from service. The evaluation identifies that only a fire in the startup transformer itself is an additional source of such a loss of offsite power as cables to the safeguards buses from the startup transformer are buried and do not pass through other fire areas. The analysis estimates the frequency of a fire in the safeguards transformer from recent Applied Reliability Engineering, Inc. 1478 27th Ave. San Francisco, CA 94122

Attachment C (pg C2)

EPRI/NRC data and shows that it is a small contributor to CDF as compared to that already evaluated in the internal events PRA.

Also, I generated results for an interim version of the updated fire IPEEE using the same assumptions as noted above for the internal events PRA and with three exceptions noted no fire area where there was a significant increase in CDF as a result of the random failure of the startup transformer following a fire. The three exceptions were the east turbine building (FA23E in the fire IPEEE), the screenhouse (FA9A) and the DG1-2 room (FA6).

Review of the cut sets causing the increase in CDF revealed that they were due to conservative assumptions in the interim fire PRA or were not applicable given the alignment of the safeguards buses to the startup transformer while the safeguards transformer is out of service.

Therefore, consistent with the Technical Letter, the review indicated that the increase in risk from fires with the safeguards bus out of service is likely less than that estimated for the internal events PRA.

For seismic events, the analysis correctly notes that the likelihood of a seismic induced loss of offsite power is no greater with the safeguards transformer removed from service.

This is due to the fact that ceramic insulators drive the potential for loss of offsite power during a seismic event and the potential for this failure mode leading to loss of power from the startup and safeguards transformers is highly coupled.

This leaves the random failure of the startup transformer subsequent to a seismic event (sufficiently small that it does not directly result in a loss of offsite power) as the principal source of risk increase following a seismic event. A review of the hazards curve for Palisades suggests that this source of offsite power loss is very small, much less than that already quantified in the internal events PRA.

The Technical Letter concludes by demonstrating the change in large early release frequency is small. By itself, the change in CDF is sufficiently small to meet both the ICCDP and ICLERP criteria.

That the change in LERF is even smaller is because removal of the safeguards transformer from service does not impact the potential for the dominant failure modes of the containment following a transient and the frequency of large early releases can be expected to remain a small fraction of CDF.

In conclusion, the dominant contributor to risk with the safeguards transformer removed from service appears to be from internal events.

Reviewing the results of the internal events PRA, the largest fraction of this increase in risk is from the increased frequency of a plant centered loss of offsite power with the additional random failure of AFW and OTC. That subsequent random failures must occur, in addition to the loss of the startup transformer, is the reason that the change in risk associated with the removal of the safeguards transformer from service is acceptably small.

Sincerely, Dave Blanchard Applied Reliability Engineering, Inc.

1478 27th Ave. San Francisco, CA 94122