ML17311B168

Safety Evaluation Supporting Amends 98,86 & 69 to Licenses NPF-41,NPF-51 & NPF-69,respectively

ML17311B168
Person / Time
Site:	Palo Verde
Issue date:	09/01/1995
From:	NRC (Affiliation Not Assigned)
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ML17311B167	List: ML17311B166 ML17311B168
References
NUDOCS 9509080327
Download: ML17311B168 (10)

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'NITED'STATES NUCLEAR,REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO.

'98 TO FACILITY OPERATING LICENSE NO.

NPF-41 AMENDMENT NO 86 TO FACILITY OPERATING LICENSE NO NPF 51 AND AMENDMENT NO.

69 TO FACILITY OPERATING LICENSE NO.

NPF-74 ARIZONA PUBLIC SERVICE COMPANY ET AL.

PALO VERDE NUCLEAR 'GENERATING STATION UNIT NOS.

1 2

AND 3 DOCKET NOS.

STN 50-528 STN 50-529 AND STN 50-530

1.0 INTRODUCTION

By letter dated March 31, 1995, the Arizona Public Service Company (APS or the licensee) submitted a request for changes to the Technical Specifications (TSs) for the Palo Verde Nuclear Generating Station, Units 1, 2, and 3

(Appendix A to Facility Operating License.Nos.

NPF-41, NPF-51, and NPF-74, respectively).

The Arizona Publ,ic Service Company submitted this request on behalf of itself, the Salt River Project Agricul,tural Improvement and Power District, Southern California Edison

Company, El Paso Electric Company, Public Service Company of New Mexico, Los Angeles Department of Water and

Power, and Southern California Public Power Authority.

The licensee has proposed changes to its Technical Specifications (TS) to be consistent with Combustion Engineering (CE) Revised Technical Specifications, NUREG-1432.

These proposed changes would clarify the shutdown margin definition, change the shutdown.margin applicabil.ity and'urveillance requirements to comply with safety analysis assumptions for subcritical inadvertent control element assembly withdrawal (UFSAR Section 15.4),

and expand the applicability for core protection calculator (CPC) operability.

In addition, the proposed amendment would add a reference to the Core Operating Limits Report for the 'MODE 6 refueling boron concentration, limit.

The amendment would also change the:power calibration requirements for the linear power level, the CPC delta T power signal, and CPC nuclear power signal to allow more conservative settings than previously requested.

2.0 PROPOSED CHANGES TO THE TECHNICAL SPECIFICATIONS 2.1 TS Definition 1.29 This change adds a sentence to clarify that the reactivity worth of any full-length control element assemblies (CEAs) that are not capable of being fully inserted must be accounted for in the determination of the shutdown margin.

This change is consistent with the definition of shutdown margin given in the Combustion Engineering Revised Standard Technical Specifications (NUREG-1432).

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2.2 TS 'Section 3 4.1.1 This change revises the mode applicabilities for Limiting Conditions for Operation (LCOs) 3. 1. 1. 1 and 3. 1. 1.2, adds a new LCO 3. 1. 1.2c, adds new Surveillance Requirements (SRs)

4. 1. 1. 1.3 and 4. 1. 1.2.3 (existing SR 'F 1. 1.2.3 is renumbered as SR 4. 1. 1.'2.4),

and modifies SRs 4. 1. 1.2. 1 and 4. 1. I.2.2.

2.3 TS 3.1.1.1 This revision changes the, applicability to MODES 3, 4, and 5 wi.th,reactor trip breakers open so that.the CEA drive system is not capable of withdrawing the CEA.

Currently, this TS requires a shutdown margin >1.0X delta k/k in MODES 3, 4, and 5 with all,full-length CEAs fully inserted.

2.4 TS 3'.1.1.2 This revision changes the applicability to MODES 1, 2, 3, -4, and 5 with reactor trip breakers closed so that the CEA drive system is capable of withdrawing the CEA.

The SRs for this LCO are changed to be consistent with the revised LCO applicability requirement.

Currently, this TS specifies the shutdown margin requirement in MODES 1, 2, 3, 4, and 5 with any full-length CEA fully or partial.ly withdrawn.

2.5 TS 3.1.1.2c This addition. ensures that reactor criticality will not be achieved, with shutdown group CEA movement.

Currently, this TS does not contain specific requirements to ensure that the reactor wil.l not achieve criticality upon shutdown. group CEA movement.

2.6 Surveillance Re uirement SR

4. 1. 1. 1.3 This addition addresses situati'ons in whi'ch one or more CEAs may be fully or partially withdrawn with the reactor trip breakers open (i.e., stuck CEA failing to insert).

This additional SR requires that the shutdown margin be determined within one hour after detection of the withdrawn CEA(s) and at least once every 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> thereafter while the CEA(s) is withdrawn.

This revision deletes the requirement to increase the shutdown margin by an amount equal to an immovable or untrippable CEA, since the proposed clarified shutdown margin definition (TS Section 1.29) contains this.requirement.

2.'8 SR 4.1.1.2.3 This addition ensures that the safety analysis assumptions are complied with using TS limits rather than administrative controls.

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2.9 SR 4.1.1.2.1b This revision requires that shutdown margin is verified within the limits specified in the COLR when CEA group withdrawal is not within the limits of TS 3.1.3.6.

Currently, the TS does not require that shutdown margin be verified if the limits of TS 3. 1.3.6 are not met.

This change is consistent with the guidance given in NUREG-1432.

2.10 TS 'Bases Section 3 4.1.1 This revision is consistent with the preceding changes and revises the lower reactor coolant system (RCS) temperature when the inadvertent deboration event becomes limiting from 210'F to 350 F to be consistent with the Core Operating Limits Report (COLR).

2.11 TS Table 3.3-1 This revision requires that either the core protection calculators (CPCs) are Operable in MODES 3, 4, and 5 with the protective system trip breakers in the closed position, the.CEA system capable of withdrawing the

CEA, and fuel in the reactor vessel, or that the logarithmic power level - High trip is Operable with the trip setpoint lowered to the CPC bypass level (i.e.,

g10 X

of rated thermal power).

2. 12 TS Table 4.3-1 Table Notat'on This revision requires adjustment of the linear power level, the CPC delta T

power signal, 'and CPC nuclear power signal to match or be, more conservative than the calorimetric power,if from 15 percent to 80 percent of RATED THERMAL POWER the difference is less than -0.5 percent or greater than 10 percent

and, for greater than 80 percent of RATED THERMAL POWER, the absolute difference is greater than 2 percent.

2.13 TS Sections 3 4.9.1 and 6.9.1 These revisions replace the requirement to maintain the 'boron concentration in MODE 6 in the RCS hand refueling canal at a K,<< of <0.95 or a boron concentration of >2150 ppm with the requirement to maintain the boron concentration within the limit specified in the COLR.

This revision requires that the TS Section 3.9. 1 MODE 6 boron concentration is included in the COLR.

2.15 TS 6.9.1.10 This revision confirms that the NRC-approved ROCS computer code is used to determine the TS Section 3.9. 1 MODE 6 boron concentration limit.

Upon approval of this proposed TS change, a section would be added to the

COLR,

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s noting the minimum refueling boron concentration:(in ppm) required to ensure K,<< remains ~0.95.

2. 16 TS Bases Section 3 4.9. 1 This revision confirms that the boron concentration l.imit specified in the COLR ensures a K,<< of g0.95 during the refueling operation.

3.0 EVALUATION

3. 1 Evaluation of Chan es Listed in Sections

2. 1 throu h 2. 10 above The above changes to the TSs ensure that the safety analysis assumptions for the subcritical inadvertent CEA bank withdrawal (UFSAR Section 15.4. 1) will be valid.

The critical safety analysis assumptions that have not been explicitly covered by TSs are that (1) a reactor trip,wil.l occur at a power level of

~10 X of RATED THERMAL POWER for inadvertent subcritical regulating CEA bank withdrawal and (2)

RCS boration is sufficient to prevent criticality based on movement of the shutdown CEA banks.

The additional SRs address situations in which one or more CEAs may be partially or fully withdrawn with the reactor trip breakers

open, ensuring operation within safety analysis assumptions if one or more CEAs are stuck and do not insert when the reactor trip breakers open.

.Since inadvertent CEA withdrawal is not possible when the reactor trip breakers are open, it is.not necessary to meet the greater shutdown margin that is required when the reactor trip breakers are closed.

The above changes are consistent with the guidance provided in NUREG 1432 and are acceptable.

3.2 Evaluation of Chan es Listed in Sections. 2. 11 and 2. 12 above These changes to the TSs wil.l ensure that the allowable power calibration errors during power ascension for the linear power level, the CPC delta T

power signal and CPC nuclear power signal are conservative relative to calorimetric power.

Raising. the tolerance range from i2 percent to between

-0.5 percent and 10 percent from 15 percent to 80 percent of RATED THERMAL POWER will allow more conservative settings than currently required and will meet the analysis assumptions not.met by a -2 percent tolerance.

The above changes are, consistent with the guidance provided in NUREG 1432 and are acceptable.

3.3 Evaluation of Chan es Listed in Sections

2. 13 throu h 2. 16 above These changes to the TSs will ensure that the MODE 6 boron concentration is maintained within the limit for boron concentration specified in the COLR.

This change enhances the human, performance process by giving pl,ant operators the specific boron concentration requirement necessary to ensure the Kg<<

value of <0.95 required in MODE 6 is met.

The boron concentration limit specified in 'the COLR will be based on core reactivity at the beginning of cycle (the end of refueling) with all CEAs withdrawn and will include an uncertainty allowance.

The additional requirement to maintain a boron concentration of at least 2150 ppm is not necessary because maintaining the boron -concentration sufficient to ensure a K,<< of <0.95 (based on core

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reactivity at the beginni'ng of cycle) will ensure the MODE 6 requirement is met to supply the required margin of safety during refueling operation.

The licensee conforms to GL 88-16, "Removal of Cycle Speci'fic Parameters Limits from Technical Specifications,"

in the relocation of the boron concentration limits to the COLR.

The cycle specific parameters are consistent with the PVNGS UFSAR and their 50'.36 requirements are met.

3.4 Conclusion The staff has reviewed'he.licensee's proposed changes and finds that these changes are consistent with Combustion Engineering 'Revised Technical Specifications.

(NUREG-1432) and are, therefore, acceptable.

4.0.

STATE CONSULTATION In accordance with the Commission's regulations, the Arizona State official was notified of the proposed'ssuance of the amendments.

The State official had no comments.

5. 0 ENVIRONMENTAL CONSIDERATION The amendments change a requirement with respect to the installation or use of a facility component located within the restricted area as defined in 10 CFR Part 20 and change surveillance requirements.

The NRC staff has determined that the amendments involve no significant increase in the amounts, and no significant change in the types, of any effluents that may be released

offsite, and that there is no significant increase in individual or cumulative occupational radiation exposure.

The Commission has previously issued a

proposed finding that the. amendments involve no significant hazards considera-

tion, and there has been no.public comment on such finding (60 FR 29871).

Accordingly, the amendments meet the eligibility criteria for categorical exclusion set forth in 10 CFR 51.22(c)(9).

The amendments also involve changes in recordkeeping, reporting or administrative procedures or requirements.

Accordingly, with respect to these, items, the amendments meet the eligibility criteria for categorical exclusion set forth in 10"CFR 51.22(c)(10).

Pursuant to 10 CFR 51.22(b) no environmental'mpact statement or environmental assessment need be prepared in connection with the issuance of the amendments.

6.0

~CONC U

0 The Commission has concluded, based on the considerations discussed

above, that (1) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed manner,,

(2) such activities will be conducted in compliance with the Commission's regulations, and (3) the issuance of the amendment will'ot be inimical to the common defense and security or to the health and safety of the public.

Principal Contributors:

C.

Thomas L. Kopp Date:

September 1,, 1995

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