ML20199K637

Corrected Suppl 1 to Application for Amends 152 & 136 to Licenses NPF-10 & NPF-15,respectively

ML20199K637
Person / Time
Site:	San Onofre
Issue date:	01/09/1998
From:	Nunn D SOUTHERN CALIFORNIA EDISON CO.
To:
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ML20199K618	List: ML20199K614 ML20199K637 ML20199K645
References
NUDOCS 9802060233
Download: ML20199K637 (12)

Text

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UNITED STATES OF AMERICA NUCLEAR REGULATOPY COMMISSION Application of SOUTHERN CAllFORNIA

)

Docket No. 50-361 EDISON COMPANY, El R.

for a Class 103

)

License to Acquire, Possess, and Use

)

a utilization Facility as Part of

)

Amendment Application Unit No. 2 of the San Onofre Nuclear

)

No. 152, Supplement 1 Generating' Station

)

SOUTHERN CALIFORNIA-EDIS0N COMPANY,-El R. pursuant to 10 CAR 50.90, hereby submit-Amendment Application No. 152.

This amendment application consists of Proposed Change Number (PCN)-451, Supplement 1 to Facility Operating License No. NPF-10.

PCN-451 is a request l 5@1 to revise Unit 2 Technical Specification 3.5.1, " Safety Injection Tanks," to

1) extend, in general, the Completion Time for a single inoperable Safety Injection Tank (SIT) from I hour to 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.and 2) extend the Completion -Time-from I hour to 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> for a single inoperable SIT when the SIT is inoperable due to malfunctioning SIT water level and/or nitrogen cover pussure I

instrumentation.

Supplement 1 adds ~a new TS 5.5.2.14, " Configuration Risk Management Program."

The purpose of the configuraticn Risk Management Program-(CRMP)_is to ensure that a proceduralized_Probabilistic Risk Assessment-informed process is in place that assesses the overall impact of plant maintenance on plant r_isk.

Implementation of the CRMP will enable appropriate actions to-be taken or 591 decisions to be made to minimize and control risk when performing on-line

-maintenance-for Systems, Structures, and Components with a risk-informed Completion Time.

Proposed TS 5.5.2.14 will be applicable to TS 3.5.1 because the Completion Times for TS 3.5.1 have " risk-informed Completion Times."

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UNITED STATES OF AMERICA NUCLEAR REGULAf0RY COMMISSION Application of SOUTHERN CALIFORNIA

)

Docket No. 50-362 3

EDIS0N COMPANY, U M.

for a Class 103

)

License to Acquire, P ssess, and Use

)

a Utilization Facility as Part of

)

Amendment Application Unit No. 3 of the San Onofre Nuclear

)

No. 136, Supplement 1 Generating Station

)

SOUTHERN CALIFORNIA EDIS0N COMPANY, H E. pursuant to 10 CFR 50.90, hereby submit Amendment Application No. 136.

This amendment application consists of Proposed Change Number (PCN)-451, Supplement I to Facility Operating License No. NPF-15.

PCN-451 is a request l5p.1 9

to revise Unit 3 Technical Specification 3.5.1, " Safety Injection Tanks," to

1) extend, in general, the Completion Time for a single inoperable Safety Injection iank (SIT) from I hour to 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> and 2) extend +h Completion Time from I hour to 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> for a single inoperable SIT when tm 2,iT is inoperable due to malfunctioning SIT water level and/or nitrogen cover pressure instrumentation.

Supplement 1 adds a new TS 5.5.2.14, " Configuration Risk Management Program."

The purpose of the Configuration Risk Management Program (CRMP) is to ensure that a proceduralized Probabilistic Risk Assessment-informed process is in place that assesses the overall impact of plant maintenance on plant risk.

Implementation of the CRMP will enable appropriate actions to be taken or 591 decisions to be made to minimize and control risk when performing on-line l

maintenance for Systems, Structures, and Components with a risk-informed Completion Time.

Proposed TS 5.5.2.14 will be applicable to TS 3.5.1 because the Completion Times for TS 3.5.1 have " risk-informed Completion Times."

. ~. - -. -.. _ - -.

Subscribed on this day of b k O d

,1998.

J Respectfully submitted, SOUTHERN CAllFORNIA EDISON COMPANY c-By:

(

Dwight Nunn-Vice Presiden State pf California n

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b c, personally a'ppearea A%M t c. U tu_n J, personally known to me to be the person w.ibse name is sucscricec to tne within instrument and acknowledged to me that he executed the same in his auther ezed capacity, and that by his signature on the instrument the person, or the entity upon

. behalf of which the person acted, executed the instrument.

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ENCLOSURE (PCN-451, Supplement 1)

DESCRIPTION AND SAFETY ANALYSIS

! b.1 OF PROPOSED CHANGE NPF-10/15-451, SUPPLEMENT 1 ff This is a request to evise the San Onofre Units 2 and 3 Technical Specification (TS) 3..,.1, " Safety Injection Tanks" and add a new TS 5.5.2.14,

" Configuration Risk Management Program."

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Existina St cifications Unit 2:

See Attachment "A" Unit 3:

See Attachment "B" Proposed Saecifications Unit 2:

See Attachment "C" Unit 3:

See Attachment "D" f

DESCRIPTION OF PROPOSED CHANGES In Technical Specification (TS) 3.5.1, " Safety Injection Tanks:"

The Completion Time for a single inoperable Safety Injection Tank (SIT) c is extended from I hour to 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> when the SIT is determined to be inoperable due to SIT water level and/or SIT nitrogen cover pressure being outside the prescribed limits, o

The Completion Time for a single inoperable SIT is extended from I hour to 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> when the SIT water level or SIT nitrogen cover pressure or both cannot be verified due to malfunctioning SIT water level or SIT nitrogen cover pressure instrument indications.

Included in Attachment "C" for Unit 2 and Attachment "D" for Unit 3, respectively, are rovised TS page 3.5-1 and Bases pages B3.5-7 through B3.5-10a.

Supplement 1 adds a new TS 5.5.2.14, " Configuration Risk Management Program."

The purpose of the Configuration Risk Management Program (CRMP) is to ensure that a proceduralized Probabilistic Risk Assessment-informed process is in place that assesses the overall impact of plant maintenance on plant risk.

Implementation of the CRMP will enable appropriate actions to be taken or 5,II1 decisions to be made to minimize and control risk when performing on-line maintenance for Systems, Structures and Components with a risk-informed Completion Time.

Proposed TS 5.5.2.14 will be applicable to TS 3.5.1 because the Completion Times for TS 3.5.1 have risk informed Completion Times.

BACKGROUND The SITS are passive pressure vessels partially filled with borated water and pressurized with a cover of nitrogen gas to facilitate injection into the reactor vessel during the blowdown phase of a large break Loss of Coolant Accident (LOCA). This SIT injection of borated water provides inventory to lhtt.1 assist in accomplishing i.he refill stage following blowdown.

The SITS also provide Reactor Coolant System (RCS) makeup for small break LOCAs.

1

a Each SIT is connected to an associated RCS cold leg by way of an Emergency Core Cooling System (ECCS) line, which is also utilized by the High Pressure Safety injection (HPSI) system and the Low Pressure Safety Injection (LPSI) system.

Each SIT is isolated from the RCS, during normal operations, by two check valves in series.

Each SIT discharge has a normally open and deenergized motor-operated isolation valve used to isolate the SIT from the RCS during normal depressurization ar.d cooldown evolutions.

The SIT gas pressure and volume, water volume, and outlet piping are designed to allow three of the four SITS to inject the inventory necessary to keep clad i

melt and zirc-water reaction within design assumptions following a design basis LOCA. The design assumes the loss of inventory from one SIT via the LOCA break.

The ECCS is described in Section 6.3 with the SITS specifically described in Section 6.3.2.2.1 of the San Onofre Units 2 and 3 Updated Final Safety Analysis Report (UFSAR).

DISCUSSION OF CHANGE l

Industry operating experience has demonstrated that many of the causes of SIT i

inoperability have been diagnosed and c('rected within a relatively short l

period of time, but often longer than the existing I hour Completion Time.

In several instances, diagnosis of an inoperable SIT has resulted in plant shutdowns. A review of this operating experience, as well as a general review of existing Probabilistic Risk Assessment (PRA) studies, led to questioning whether transitioning to a lower mode as required by the existing TS action provides greater reactor safety than remaining at power and repairing the inoperable SIT.

If a single SIT were to be diagnosed as inoperable for reasons other than due to boron concentration being outside the limits established by the San Onofre Units 2 and 3 TS 3.5.1, the SIT must be restored to operable status within one hour or the plant must be in at least Hot Standby within 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and the pressurizer pressure reduced to less than 715 psia within 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />.

The proposed change to TS 3.5.1 would allow continued operation up to 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />, in lieu of 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br />, to restore the SIT to operable status if the inoperability of the SIT is determined to be due to the inability to verify water level or nitrogen cover pressure or both.

The proposed TS change also allows up to 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />, in lieu of 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br />, to restore a single SIT to operable status if the SIT is declared inoperable for any reasons other than the reasons mentioned above.

The Combustion Engineering Owners Group (CEOG) Report CE NPSD-994, " Joint Applications for Safety injection Tank Completion Time /STI Extension," has demonstrated risk calculations associated with an Completion Time extension from one hout to 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />. The results of the analyses indicate that the average single and yearly Completion Time risk contributions are negligible and the average core danage frequencies (CDFs) are virtually unchanged.

The data and risk results in CE NPSD-994 pertaining to the San Onofre units were supplied and endorsed by Southern California Edison.

2

The risk assessment performed by the CE0G in CE NPSD-994 evaluated "at power risk," " transition risk," " shutdown risk," and "large early release risk " At power risk represents the risk associated with continued operation with a single SlT out of service. Transition risk represents the risk associated with reducing power and placing the plant in a Hot or Cold Shutdown mode following equipment failure.

Shutdown risk benefits were not credited for the SIT Completion Time extension.

The results of this analysis indicate that the average core damage probability (CDP) attributable to transition risk is larger than the average CDP associated with continued power operation of the plants with one SIT inoperable for the proposed Completion Time.

As part of the CEOG study an assessment was performed on the impact of the proposed Completion Time extension on large early release scenarios.

The three classes of events considered for these release scenarios include: Class 1 event category (containment bypass); Class 2 event category (severe accidents accompanied by loss of containment isolation; and Class 3 event category (containment failure associated with energetic events in the containment).

The assessment concluded that the unavailability of one SIT would not impact or alter the progression of Class 1 events since these events are characterized by an irrevocable loss of reactor inventory along with any makeup outside of containment. A small increase in Class 2 events could occur when an unmitigated large break LOCA occurs in conjunction with an initially unisolated containment.

There will be no significant fission product releases unless the containment is unscrubbed (containment sprays are inoperable).

This later combination of Class 2 events is considered of very low probability.

Class 3 events are dominated by RCS transients that occur at high pressure. These events exclude those where SIT performance would be called for and therefore SIT status is not a contributor to this event category.

Therefore, the assessment concluded that the unavailability of one SIT will result in a negligible impact on the large early release probability for San Onofre.

TS 3.5.1 does not differentiate between a SIT that is inoperable due to tank inventory or nitrogen gas pressure discrepancies and a SIT whose inventory or gas pressure cannot be verified due solely to malfunctioning water level instrumentation or pressure instrumentation or both.

Because these instruments provide no safety actuation, it is reasonable to extend the Completion Time since the SIT is available to perform its safety function during this time.

This proposed change is in accordance with the provisions of NUREG-1366, " Improvements to Technical Specifications Surveillance Requirements," and Generic Letter 93 <3, "Line Item Improvements to Reduce Surveillance Requirements for Testing During Power Operation."

The CEOG study concluded that the overall plant risk with this proposed Completion Time is either risk beneficial or, at the very least, risk neutral.

The Surveillance Test Interval (STI) portion of CE NPSD-944 deals with boric acid concentration sampling surveillance requirements. A change to the boron sampling requirements, which eliminates a surveillance when the SIT makeup water is from the Refueling Water Storage Tank (RWST), was evaluated and endorsed by the NRC in NUREG-1366.

This change is already incorporated in the Improved Standardized Technical Specifications for San Onofre Units 2 and 3.

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To ensure plant safety is maintained and monitored San Onofre will implement a Configuration Risk Management Program (CRMP) which is to be applicable to TS 3.5.1.

1.

Purpose of CRMP The purpose of the Configuration Risk Management Program (CRMP) is to ensure that a proceduralized Probabilistic Risk Assessment (PRA)-

]

informed process is in place that assesses the overall impact of plant maintenance on plant risk.

Implementation of the CRMP will enable appropriate actions t-be taken or decisions to be made to minimize and control risk when periorming on-line maintenance for Systems, Structures, and Components (SSCs) with a risk-informed Completion Time.

2.

Scope of CRMP The scope of the SSCs included in the CRMP are those SSCs considered High Safety Significant per the Maintenance Rule regulatory guide (Regulatory Guide 1.160, Rev. 2).

The Configuration Risk Management Program (CRMP) includes the following components and key elements:

Components a.

Risk Assessment Tool b.

Tier 2 restrictions c.

Level 2 and External Events d.

Decision Making Process e.

Associated Procedures 5,(t,1 Key Element 1.

Implementation of CRMP The intent of the CRMP is to implement a(3) of the Maintenance Rule (10CFR50.65) with respect to on-line maintenance for risk-informed technical specifications, with the following additions /

clarifications:

a.

The scope of SSCs to be included in the CRMP will be the SSCs considered High Safety Significant per Regulatory Guide 1.160, Rev. 2.

b.

The CRMP assessment tool is PRA informed, and may be in the form of either a risk matrix, an on-line assessment, or a direct PRA assessment.

c.

CRMP will be invoked as follows for:

t Risk-Informed Inoperability: A risk assessment will be performed prior to entering the LC0 Condition for preplanned activities.

For unplanned entry into the LC0 Condition, a risk assessment will be performed in a timeframe consistent with the plant's Corrective Action Program.

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4 Additional SSC Inoperability and/or Loss of Functionality:

When in the risk-informed Completion Time, if an addititnal high safety significant SSC becomes inoperable /non-functional, a risk assessment shall be performed in-a timeframe consistent with the plant's Corrective Action Program, d.

Tier 2 commitments apply for planned maintenance only, but will be evaluated as part of the Tier 3 assessment for unplanned occurrences.

Key Element 2.

Control & Use of the CRMP Assessment Tool a.

Plant modifications ar.d procedure changes will be monitored, assessed, and dispositioned.

Evaluation of changes in plant configuration or PRA model features can be dispositioned by implementing PRA model changes or by the qualitative assessment of the impact of the changes on the CRMP assessment tool. This qualitative assessment recognizes that changes to the PRA take time to implement and that changes can be effectively compensated for without compromising the ability to make sound engineering judgments.

Limitations of the CRMP assessment tool are identified and understood for each specific Completion Time extension.

b.

Procedures exist for the control and application of CRMP assessment tools, including description of process when outside the scope of the CRMP assessment tool.

591 Key Element 3.

Level 1 Risk-Informed Assessment The CRMP assessment tool is based on a Level 1, at power, internal events PRA model.

The CRMP assessment may use any combination of quantitative and qualitative input.

Quantitative assessments can include reference to a risk matrix, pre-existing calculations, or

- new PRA-analyses, a.

Quantitative assessments should be performed whenever necessary for sound decision making.

b.

When quantitative assessments are not necessary for sound decision making, qualitative assessments will be performed.

Qualitative assessments will consider applicable, existing insights from quantitative assessments previously performed.

Key Element 4.

Level 2 Issues / External Events External events and Level 2 issues are treated qualitatively and/or quantitatively.

Guidance for implementing the CRMP is provided by plant procedures.

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SAFETY ANALYSIS The proposed change described above shall be deemed to involve a significant hazards consideration if there is a positive finding in any cae of the following areas:

l.

Will operation of the facility,in accordance with this proposed change involve a significant increase in the probability or consecuences of an accident previously evaluated?

Response: No The Safety injection 'taaks (SITS) are passive components in the Emergency Core Cooling System (ECCS).

The SITS are not accident-initiators in any accident previously evaluated.

Therefore, this change dees not involve an increase in the probability of an accident previously evaluated.

The SITS are designed to mitigt', the consequences of Loss of Coolant Accidents (LOCAs).

The proposed changes do not affect any of the assumptions used in deterministic LOCA analysis.

Therefore, the 4

consequences of accidents previously evaluated do not change.

Tc fully evaiuate the SIT Completion ' ie extension, Probabilistic-Safety Analysis (PSA) methods were utilized.

The results of these analyses show no significant increase in core damage frequency. As a result, there would be no significant increase in the conseyences of an accident previously evaluated.

The proposed change pertaining to SIT inoperability based solely on instrumentation malfenction does not involve a significant increase in the consequences of an accident-as evaluated and endorsed by the Nuclear Regulatory Commission (NRC) in NUREG-1366, " Improvements to Technical i

Specifications Surveillance Requirements."

The Configuration Risk Management Program is an Administrative-Program that assesses risk based on plant status.- Adding the requirement td implement this program for Technical Specification 3.5.1 does not affect 5@j-3 the probability or the consequences of an accident.

Therefore, this change does att involve a significant increase in the probability or consequences of any accident previously evaluated.

2.

'Will operation of the facility in accordance with ihis proposed c u nge create the possibility of a new or different kind of accident f,.... any accident previously evaluated?

Response:- No J

This proposed change does not change the design, configuration, or method of operation of the plant.

Therefore, this change does nal creata the possibility of a new or different kind of accident from any j

previously evaluated.

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3.

Will operation of the facility in accordance with this proposed change involve a significant reduction in a margin of safety?

Response

No The )roposed changes do not affect the limiting conditions for operation or t1eir bases that are used in the deterministic analyses to establish the-margin of safety.

PSA evaluations were used to evaluate these changer.

These evaluations demonstrate that the changes are either risk neutral or risk beneficial.

Therefore, this change does agi involve a significant reduction in a margin of safety.

Safety and Sionificant Hazards Determination Based on the above Safety Analysis, it is concluded that: 1) the proposed change does not constitute a significant hazards consideration as defined by 10 CFR 50.92 and 2) there is reasonable assurance that.the health and safety of the public will not se endangered by the proposed change. Moreover, because this action does not involve a significant hazards consideration, it will also not result in a condition which significantly alters the impact of the station on the environment as-described in the NRC-Final Environmental Statement.

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