ML20195J896

Amends 182 & 168 to Licenses NPF-10 & NPF-15,consisting of Proposed Tech Spec Change Number 498,revising TS 3.3.1, RPS Instrumentation - Operating

ML20195J896
Person / Time
Site:	San Onofre
Issue date:	11/23/1998
From:	Nunn D SOUTHERN CALIFORNIA EDISON CO.
To:
Shared Package
ML20195J890	List: ML20195J886 ML20195J896 ML20195J902
References
NUDOCS 9811250105
Download: ML20195J896 (8)

Text

_ ____________

UNITED STATES OF AMERICA NUCLEAR REGULATORY COMMISSION Application of SOUTHERN, CALIFORNIA

)

EDISON COMPANY, ET AL. for a class 103

)

Docket No. 50-361 License to Acquire, Possess, and Use

)

a Utilization Facility as Part of

)

Amendment Application Unit No. 2 of the San Onofre Nuclear

)

No. 182 Generating Station

)

SOUTHERN CALIFORNI A EDISON COMPANY, EI A.L. pursuant to 10CFR50.90, hereby submit Amendment Application No. 182. This amendment application consists of Proposed Change No. PCN-498 to Facility Operating License NPF-10.

PCN-498 is a request to revise footnotes (a) and (d) to Table 3.3.1-1 in Technical Specification 3.3.1.

Subscribed on this day of kU6hv

, 1998.

Respectfully Submitted, SOUTHERN CALIFORNIA EDIS0N COMPANY By 2M Dwight E. h t nn Vice Presic nt State of Californla County of San Diego On before me, b

b.

personally appeared I

personally known to me rer gu u n d t ^ -- - t hn__ba s i s.nfat4sfano ry e v i uced. to be the pe rso n % who s e name% is/4.c.c subscribed to the within Instrument and acknowledged to me that helchnithny. executed the same in his/hc r ' ' ^!: authorfled capacity %), and that by his/hetMAc.it signature N on the instrument the person (q. or the entityuponbehalfofwhichtheperson(() acted, executed the Instrument.

W11NESSm3y i

and official seal.

S1gnature

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No' cry Puerc. California f San Diego County i

I MyComet Egies Oct14,ZIn

-.-.p 9811250105 981123' PDR ADOCK 05000361 P

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UNITED STATES OF AMERICA NUCLEAR REGULATORY COMMISSION Application of SOUTHERN, CALIFORNI A

)

EDIS0N COMPANY, ET AL. for a class 103

)

Docket No. 50-362 License to Acquire, Possess, and Use

)

a Utilization Facility as Part of

)

Amendment Application

!'elit No. 3 of the San Onofre Nuclear

)

No. 168 benerating Station

)

SOUTHERN CALIFORNIA EDISON COMPANY, EI AL. pursuant to 10CFR50.90, hereby submit Amendment Application No.168.

This amendment application consists of Proposed Change No. PCN-498 to Facility Operating License NPF-15.

PCN-498 is a request to e '. 4 n iootnotes (a) and (d) to Table 3.3.1-1 in Technical Specifi cation 3.3.1.

Subscribed on this day of f4 T

., 1998.

Respectfully Submitted, SOUTHERN CALIFORNIA EDISON COMPANY

(

e( -

By:

Dwight E. tunn,

4 Vice Presi ent State of California County of San Diego On before me,/

Il b

b pei; anally appeared M he/onally known to me h l'

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i_ b;;i- ^' ;; d,' n iu,, e&4dex.e3 to be the person whose tiameBQ lh subscribed to the within instrument and acknowledged to me that he/' bry executed the same

• isH" 'rtr authorized capacity (k), and that by his A,;W signature (y on the instrument the person \\),

or the entity upon behalf of which the person acted, executed the instrument.

WITNESS my hand and official seal.

"-^^-------^-=

4 MAR'ANE SANCHE2 Commission # 1196482 Signature /

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No*Gy PvDGc-Cofifomio l i

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DESCRIPTION OF TECHNICAL SPECIFICATION CHANGE PCN-498 SAN ONOFRE Units 2 and 3 Change Number PCN-498 will revise Technical Specification 3.3.1, " Reactor Protective System (RPS) Instrumentation - Operating."

Existing Technical Specifications:

Unit 2: See Attachment A i

Unit 3: See Attachment B Proposed Technical Specifications:

1 Unit 2: See Attachment C (redline and strikeout)

Unit 3: See Attachment D (redline and strikeout)

Proposed Technical Specifications:

Unit 2: See Attachment E Unit 3: See Attachment F Proposed UFSAR: See Attachment G Description of Change:

The proposed change to Technical Specification (TS) 3.3.1 consists of revising Notes (a) and (d) to Table 3.3.1-1 to change the specified setpoints, to provide allowable values for the automatic 3

enable setpoints, and to clarify the nature of the measured parameter.

Amendment No.142 (submitted as PCN 500) was issued under emergency conditions for Unit 2 only on September 25,1998. This amendment corrected a long-standing incorrect use of terms

(' THERMAL POWER' for ' logarithmic power') in Notes (a) and (d), the subject of this amendment request. Since the comparable emergency circumstances did not apply to Unit 3, the change proposed in PCN 500 will be issued separately at a later date. The subsequent discussion will describe this proposed change (ie: PCN 498) using current Unit 2 nomenclature (Note the Unit 3 ' Existing Technical Specifications' read differently). Also, the ' Proposed Technical Specifications' will show incorporation of both this proposed change, PCN 498, and the emergency proposed change, PCN 500, for both Units.

l l

Note (a) to Table 3.3.1-1 currently permits bypassing the Logarithmic Power Level -- High (log L

Power) trip when logarithmic power is > 1E-4% RATED THERMAL POWER (RTP) and I

requires automatic enable of the Log Power trip to occur at a setpoint of $ IE-4% RTP when reactor power is decreasing. Note (d) to Table 3.3.1-1 currently permits bypassing the Reactor Coolant Flow -- Low, the Local Power Density -- High, and the Departure From Nucleate Boiling Ratio -- Low (RCS Flow /LPD/DNBR) trips when logarithmic power is < 1E-4% RTP and t

requires automatic enable of the RCS Flow /LPD/DNBR trips to occur at a setpoint of 2 lE-4%

RTP when reactor power is increasing. Both enables (Log Power and RCS Flow /LPD/DNBR) are accomplished by the same bistable device for each channel. The RCS Flow /LPD/DNBR trips enable occurs when the bistable trips; the Log Power trip enable occurs when the bistable resets.

The bistable reset occurs at a lower reactor power level than the trip. Consequently, with the i

RCS Flow /LPD/DNBR enable correctly set at less than IE-4% RTP, the Log Power enable will occur at a reactor power level less than IE-4% RTP (typically around 8E-5% RTP), contrary to the requirement of Note (a).

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' Thus, the current wording of the TS and the installed and approved RPS instrumentation are l

incompatible. Revising Notes (a) and (d) to provide a setpoint compatible with the installed l

instrumentation corrects this problem. The proposed revision also clarifies that the setpoints are l

set relative to logarithmic power (not THERMAL POWER), and that manual enable of the trip is 1

l permissible (by deleting the word " automatically"). The proposed setpoints are " allowable l

values," consistent with the other setpoints in Table 3.3.1-1.

l Discussion:

A. General SCE has evaluated the impact ofintroducing the allowable values irto Notes (a) and (d) on the UFSAR Chapter 15 design basis events. Figure 1 shows the allowable and safety analysis values for the logarithmic power and RCS Flow /LPD/DNBR trip enable setpoints. As describcd in Section B, SCE has concluded that an allowable value for the Log Power trip automatic enable of 2 4E-5% RTP provides adequate reactor protection. Therefore, the proposed wording of Note L

(a) to Table 3.1.1-1 requires the Log Power trip to be enabled at logarithmic power levels less than 4E-5% RTP. It should be noted that if the trip iz not manually enabled before logarithmic power decreases to 4E-5% RTP, then the trip will be automatical!y enabled by that allowable value.

As described in Section B, SCE has similarly determined that an allowable value for the RCS Flow /LPD/DNBR trips enable of51.5E-4% RTP provides adequate reactor protection.

l Therefore, the proposed wording of Note (d) to Table 3.1.1-1 requires the RCS Flow /LPD/DNBR trips to be enabled at logarithmic power levels greater than 1.5E-4% RTP.

Again it should be noted that if the trip is not manually enabled before logarithmic power l

increases to 1.5E-4% RTP, then the trips will be automatically enabled by that allowable value.

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a

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l Figure 1: Bistable Allowable & Safety Analysis Values.

s L Safety Analysis Value 1 x 10~3 % Power (DNBR/LPD/ Low Flow)

Allowable Value (Increasing 1.5 x 10-4 % Power Power)

Setpoint 1 x 10-4 % Power l

Allowable Value 4 x 10_3 % Power i

(Decreasing Power)

Safety Analysis Value 1 x 10*5 % Power (Log Power) l l

r

B. Analyses in order to determine the impact of the proposed change in the Notes (a) and (d), an assessment was performed of the UFSAR Chapter 15 events. Note (a) impacts the logarithmic power bypass and Note (d) applies to the CPC DNBR or LPD trip and the RCS flow trip. Based on the allowable values of 4E-5 % power for the decreasing setpoint (i.e. log power trip enable) and 1.5E-4 % power for the increasing setpoint (i.e. RCS Flow /LPD/DNBR trip enable),

conservative safety analysis limits of < l.0E-5 for the log power trip enable and > 1.0E-3 for the RCS Flow /LPD/DNBR trip enable were used in the safety analysis.

All of the relevant UFSAR Chapter 15 safety analysis events were assessed for San Onofre Units 2 and 3 with regards to the impact of the above TS modification. The events adversely impacted by this change were the uncontrolled control element assembly (CEA) withdrawal from subcritical and low power. These events are discussed below:

UFSAR Section 15.4.1.1 Uncontrolled CEA withdrawal from Subcritical and Low Power (i) Uncontrolled CEA Withdrawal From Subtritical The event is analyzed to the fuel failure and peak RCS pressure criteria. The worst case initial condition for this event is from a core power of approximately 1E-8% power. The credited reactor trip is the logarithmic power trip at a setpoint of 4% rated thermal power. Reducing the enabling setpoint from lE-4% power to lE-5% power reduces the operating space requiring protection from the log power trip. Therefore since the worst case initial condition is still maintained and the log power trip setpoint remains unchanged, the change to Note (a) will have no adverse impact on the consequences of this event.

The change in the RCS Flow /LPD/DNBR trip enable setpoint from lE-4% power to IE-3%

power could potentially impact this event in several ways. If out-of-sequence regulating or shutdown bank withdrawals were eliminated from consideration by crediting the LPD/DNBR trips, the later enabling setpoint would have to be specifically considered in determining the worst case condition for this event. However, for SONGS 2 & 3, all regulating and shutdown banks were surveyed to determine the worst CEA bank withdrawn. Therefore, no LPD/DNBR trip credit was required to eliminate out-of-sequence regulating or shutdown banks.

The second potential impact applies if the event credited the RCS Flow trip or the Core Protection Calculator pump speed auxiliary trip. These trips are credited for this event with less than four Reactor Coolant pumps operating. The event was reanalyzed for part loop operation with the IE-3% CPC DNBR & LPD and RCS low flow trip enable analyticcl setpoint. The results show that the consequences of this event remain bounded by the analysis as presented in UFSAR Section 15.4.1.1. Therefore, the change to Note (d) will have no adverse impact on the cc,nsequences of this event.

(ii) Uncontrolled CEA witi.drawal from low power

This event is also analyzed to the fuel failure and peak RCS pressure criteria. The change in Notes (a) and (d) will extend the range ofinitial power conditions protected by this portion of the event from lE-4% power to IE-5% power. The worst case initial condition for this event is at the low power condition. This event was thus reanalyzed to accommodate the allowable range window of the enable setpoint. The results of this reanalysis show that the fuel centerline melt acceptance criterion of 4706 F, the DNBR acceptance criterion of 1.31, and the peak RCS pressure acceptance criterion of 110% design pressure are met for this event.

No Significant llazards Considerations:

The Commission has provided standards for determining whether a significant hazards consideration exists as stated in 10 CFR 50.92. A proposed amendment to a facility operating license involves no significant hazards consideration if operation of the facility in accordance with a proposed amendment would not: (1) involve a significant increase in the probability or consequences of an accident previously evaluated; or (2) create the possibility of a new or different kind of accident from any accident previously evaluated; or (3) involve a significant reduction in a margin of safety. A discussion of these standards as they relate to this amendment request follows.

1)

Does the proposed amendment involve a significant increase in the probability or consequences of an accident previously evaluated?

No.

The proposed change to TS 3.3.1 does not adversely impact structure, system, or component design or operation in a manner which would result in a change in the l

frequency of occurrence of accident initiation. SCE has re-analyzed the relevant accidents and established that accident consequences are not significantly increased by the proposed changes to the bypass-permissive and enable setpoints. The reactor trip bypass and automatic enable functions are not accident initiators. Consequently, the proposed TS change will not significantly increase the probability of accidents previously evaluated.

Therefore, this amendment request does not involve a significant increase in the probability or consequences of an accident previously evaluated.

2)

Does this amendment request create the possibility of a new or different kind of accident from any accident previously evaluated?

No.

No new or different a:cidents result from changing the reactor trip bypass-permissive and automatic enable sete,oints. Introducing an uncenainty band for the enable setpoints delays the mitigation action of the reactor trip for the design basis analysis for the events that credit this trip. The enable setpoint itself does not cause any accident. Therefore, the amendment request does not create the possibility of a new or different kind of accident from any accident previously evaluated.

3)

. Does this amendment request involve a significant reduction in a margin of safety?

No.

SCE has re-analyzed the accidents and determined that the consequences of the accidents are within their acceptance criteria under the proposed amendment so that the margin of safety that bounds the setpoint in both directions remains intact. The analyses are relatively insensitive to the reactor trip automatic enable setpoints, and no significant reduction in the margins of safety ensues from the relatively minor proposed changes to the bypass-permissive and enable setpoints, nor from establishing allowable values for the -

setpoints.

Based on the negative responses to these three Commission criteria, SCE concludes that the proposed amendment involves no significant hazards consideration.

Environmental Consideration:

Southern California Edison has determined that the proposed TS change involves no changes in the amount or type ofeffluent that may be released offsite, and results in no increase in individual or cumulative occupational radiation exposure. As described above, the proposed TS amendment involves no significant hazards consideration and, as such, meets the eligibility criteria for categorical exclusion set forth in 10CFR51.22(c)(9).

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