ML20094K078

Application for Amends 151 & 135 to Licenses NPF-10 & NPF-15,consisting of Change Request 452,modifying PCN-299 TS 3.5.2 to Extend AOT from 72 H to 7 Days for Single LPSI Train

ML20094K078
Person / Time
Site:	San Onofre
Issue date:	11/08/1995
From:	Rosenblum R SOUTHERN CALIFORNIA EDISON CO.
To:
Shared Package
ML20094K073	List: ML20094K067 ML20094K078 ML20094K085
References
NUDOCS 9511160154
Download: ML20094K078 (9)

Text

_

UNITED STATES OF AMERICA NUCLEAR REGULATORY COMMISSION Application of SOUTHERN CALIFORNIA

)

Docket No. 50-361 EDIS0N COMPANY, EI E.

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. 151 Generating Station

)

SOUTHERN CALIFORNIA EDIS0N COMPANY, El R. pursuant to 10 CFR 50.90, hereby submit Amendment Application No. 151.

This amendment application consists of Proposed Change Number (PCN)-452 to Facility Operating License No. NPF-10.

PCN-452 is a request to revise Unit 2 post PCN-299 (Technical Specification ' Improvement Program) Specification 3.5.2, "ECCS-Operating," to extend the allowed outage time from 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> to 7 days for a single Low Pressure Safety Injection train.

9511160154 951108 PDR ADOCK 05000361 p.

PDR

i Subscribed on this b day of A)ot/cM6 E/L

,1995 Respectfully submitted, SOUTHERN CALIFORNIA EDISON COMPANY By:

/4 [

' Richard M. Rosenblum Vice President 1

State of California j

County lofl95 San Diego on h9

_before me,3M8 ARA A. hic-C/truylN07Alf DAG persorfally appeared g,*cH4rb A1. We3rvacuM

, persionally known to me to be the person whose name is subscrioed to the within instrument and acknowledged to me that he executed the same in his authorized capacity, and that by his signature on the instrument the person, or the entity upon behalf of which the person acted, executed the instrument.

WITNESS my hand and official seal.

Signature Jd44/h O. M

' ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ' '

BAmutA A,MC CAlmW v

3 Nohmy1%Asc-CaMomio E E

OllANGE COUNTY y

1 My Corrm Egees MAR 31.19pp g

UNITED STATES OF AMERICA NUCLEAR REGULATORY COMMISSION Application of SOUTHERN CALIFORNIA

)

Docket No. 50-362 EDISON COMPANY, EI al.

for a Class 103

)

l License to Acquire, Possess, and Use

)

l a Utilization Facility as Part of

)

Amendment Application l

Unit No. 3 of the San Onofre Nuclear

)

No. 135 l

Generating Station

)

l SOUTHERN CALIFORNIA EDIS0N COMPANY, EI AL. pursuant to 10 CFR 50.90, hereby submit Amendment Application No. 135.

This amendment application consists of Proposed Change Number (PCN)-452 to Facility Operating License No. NPF-15.

PCN-452 is a request to revise Unit 3 post PCN-299 (Technical Specification Improvement Program) Specification 3.5.2, "ECCS-Operating," to extend the allowed outage time from 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> to 7 days for a single Low Pressure Safety Injection train.

1

a Subscribed on this F 7h day of A/o ves d(A.

,1995.

Respectfully submitted, SOUTHERN CALIFORNIA EDIS0N COMPANY

~

By: Xu 1h

. --d h,

W Richard M.' Rosenblbm Vice President State of California County lofSanDiego _before me, 3APAAQA A. N'C ARTHY N0MY ?"

On ll 9/95 persorfalTy appeared NicNAAb M. Wor r A/A/_uM

, pertonally known to me to be the person whose name is subscribed to the within instrument and acknowledged to me that he executed the same in his authorized capacity, and that by his signature on the instrument the person, or the entity upon behalf of which the person acted, executed the instrument.

WITNESS my hand and official seal.

S 7

a co-,

i,,

3 Notery P25c-Cmomio l E

ORANGE COUNW y

g MrComm.Eoimo MAR 31,1999g 4

l

e o

DESCRIPTION AND SAFETY ANALYSIS OF PROPOSED CHANGE NPF-10/15-452 This is a request to revise the San Onofre Units 2 and 3 post PCN-299 (Technical Specification Improvement Program) Technical Specification (TS) 3.5.2, "ECCS-Operating."

Post PCN-299 (Technical Specification Imorovement Proaram) Specifications Unit 2:

See Attachment "A" Unit 3:

See Attachment "B" Proposed Specifications Unit 2:

See Attachment "C" Unit 3:

See Attachment "D" DESCRIPTION OF PROPOSED CHANGES In post PCN-299 (Technical Specification Improvement Program) TS 3.5.2, "ECCS-Operating," the Allowed Outage Time (A0T) for a single Low Pressure Safety Injection (LPSI) train is being extended from 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> to 7 days with the other LPSI train operable.

Included in Attachment "C" for Unit 2 and Attachment "D" for Unit 3, respectively, are revised LCO page 3.5-4 and revised Bases pages B3.5-16, B.5-17, B.5-18, and B.5-20a.

Due to text overflow, Bases pages B.5-19 and B.5-20 are included for completeness.

BACKGROUND San Onofre Units 2 and 3 are each equipped with two LPSI trains. A LPSI train consists of one LPSI pump and two injection flow paths, including motor-operated valves.

The LPSI trains, in combination with the two High Pressure Safety Injection (HPSI) trains, form the two redundant Emergency Core Cooling (ECCS) subsystems.

The two LPSI pumps are high volume, low head centrifugal type pumps designed to inject large quantities of borated water into the Reactor Coolant System (RCS) to flood and cool the core during the early stages of a large break Loss of Coolant Accident (LOCA).

During normal shutdown operation (Modes 4, 5, and 6), the LPSI pumps also provide shutdown cooling flow to the reactor core.

In this configuration, the LPSI pumps take suction from the RCS hot leg through the Shutdown Cooling Heat Exchanger (SDCHX) and discharge cooler water into the RCS cold leg.

The LPSI pumps take suction from the Refueling Water Storage Tank (RWST) during the injection phase of a LOCA event.

The borated water is pumped to a common LPSI discharge header consisting of four injection lines with individual injection valves prior to entering containment. Once inside containment, the LPSI injection lines combine with the HPSI and Safety i

1

o Injection Tank (SIT) injection lines and flow is directed independently through each of the four RCS cold legs into the reactor vessel.

The LPSI system pumps automatically start and the valves open upon receipt of a Safety Injection Actuation Signal (SIAS). When the RWST inventory is drawn down i

during the lnjection phase a low RWST level signal produces a Recirculation Actuation Signal (RAS). The RAS secures the LPSI pumps, opens the Containment Emergency Sump (CES) isolation valves, and shifts the suction of the HPSI pumps and the Containment Spray pumps from the RWST to the CES.

The ECCS is described in Section 6.3 with the LPSI pumps specifically described in Section 6.3.2.2.2 of the San Onofre Units 2 and 3 Updated Final Safety Analysis Report (UFSAR).

DISCUSSION OF CHANGE The San Onofre Units 2 and 3 Improved Technical Specifications (TSs) address the LPSI as a portion of the ECCS.

Post PCN-299 TS 3.5.2 requires two independent ECCS trains to be operable. With one ECCS train inoperable, based i

upon any component inoperability, the train must be returned to operability within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />.

The proposed change will allow up to 7 days to restore one LPSI subtrain to operable status (when the other LPSI subtrain is operable) should that be the cause for ECCS train inoperability.

3 The Combustion Engineering Owners Group (CE0G) Report CE NPSD-995, " Joint Applications Report for Low Pressure Safety Injection System A0T Extension,"

supports this change utilizing current Probabilistic Safety Analysis (PSA) methodologies to address the change in risk of the Allowed Outage Time (A0T) extension when compared with the current or the Improved TS time limitations.

The CE0G study considered and categorized the change in risk into "at power risk," " transition risk," and shutdown risk." Consideration of the risk factors impacted by the extension in A0T from 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> to 7 days demonstrates a negligible increase in "at power risk" (less than a 0.3% increase in average core damage frequency for all Combustion Engineering (CE) plants and less than i

a 1.5% increase in average core damage frequency for San Onofre Units 2 and l

3). To perform a more comprehensive assessment of the overall change in risk, an accounting for avoided risks associated with reducing power and transitioning to hot or cold shutdown is considered. This " transition risk" 1

is important in understanding the tradeoff between shutting down the plant, to comply with the TS Action Statement, and restoring the LPSI train to operability while at power. Also of importance is the risk avoided based on i

LPSI system maintenance while in cold shutdown, or " shutdown risk." Each time the plant is placed in cold shutdown, the LPSI system is required for decay heat removal in the shutdown cooling mode of operation. Any maintenance performed on the LPSI system during shutdown cooling operation adds to the risk of losing shutdown cooling. Therefore, performing LPSI system maintenance with the unit on-line, when the LPSI system is not normally in demand, represents a decrease in " shutdown risk."

2

The result of the CE0G integrated assessment of the overall risk associated with the adoption of the proposed LPSI system A0T extension is that the change in core damage frequency due to this A0T extension is insignificant (less than a 0.3% increase in average core damage frequency for all CE plants and less than a 1.5% increase in average core damage frequency for San Onofre Units 2 and 3). Additionally, there is a reduction in overall plant risk when this increase in risk is offset by the reduction in transition and shutdown risk.

It is the conclusion of the CEOG study that the overall plant impact will either be risk beneficial, or at the very least, risk neutral.

As part of the CE0G study an assessment was performed on the impact of the proposed A0T extension on large early release scenarios.

The assessments of the three classes of events (containment bypass, severe accidents accompanied by loss of containment isolation, and containment failure associated with energetic events in containment) considered for these scenarios concluded that the increased unavailability of one LPSI train will result in a negligible i

impact on the large early release probability for San Onofre.

j SAFETY ANALYSIS The proposed change described above shall be deemed to involve a significant hazards consideration if there is a positive finding in any one of the i

following areas:

1.

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

Response: No The Low Pressure Safety Injection (LPSI) system is a part of the Emergency Core Cooling System (ECCS).

Inoperable LPSI components are i

not considered to be accident initiators. Therefore, this change does not involve an increase in the probability of an accident previously evaluated.

The LPSI system is primarily designed to mitigate the consequences of a large Loss of Coolant Accident (LOCA). This proposed change does not affect any of the assumptions used in the deterministic LOCA analysis.

Therefore, the consequences of accidents previously evaluated do not change.

To fully evaluate the LPSI Allowed Outage Time (A0T) 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 consequences of an accident previously evaluated.

Therefore, this change does not involve a significant increase in the probability or consequences of any accident previously evaluated.

3

2.

Will operation of the facility in accordance with this proposed change create the possibility of a new or different kind of accident from any accident previously evaluated?

Response

No This proposed change does not change the design, configuration, or method of operation of the plant. Therefore, this change does not create the possibility of a new or different kind of accident from any previously evaluated.

t 3.

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

Response

No The proposed change does not affect the limiting conditions for operation or their bases that are used in the deterministic analyses to establish the margin of safety.

PSA evaluations were used to evaluate i

these changes.

j J

Therefore, this change does not 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 be endangered by the proposed change. Moreover, i

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.

i 4

s l

l l

ATTACHMENT "A" POST PCN-299 (TECHNICAL SPECIFICATION IMPROVEMENT PROGRAM) SPECIFICATIONS UNIT 2 l

,