ML17305B570

Application for Amend to License NPF-51,allowing Functional Testing of Hydraulic Snubbers in Facility to Be Performed During Upcoming Facility Refueling Outage

ML17305B570
Person / Time
Site:	Palo Verde
Issue date:	05/29/1991
From:	Conway W ARIZONA PUBLIC SERVICE CO. (FORMERLY ARIZONA NUCLEAR
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
Shared Package
ML17305B571	List: ML17305B570 ML17305B577
References
161-03982-WFC-M, 161-3982-WFC-M, NUDOCS 9106050312
Download: ML17305B570 (17)

Text

ACCELERATED DISTRIBUTION DEMONSTION SYSTEM REGULATORY INFORMATION DISTRIBUTION SYSTEM (RIDS)

ACCESSION NBR:9106050312 DOC.DATE: 91/05/29 NOTARIZED: NO DOCKET

, FACIL:STN-50-529 Palo Verde Nuclear Station, Unit 2, Arizona Publi 05000529 AUTH. NAME AUTHOR AFFILIATION CONWAY,W.F. Arizona Public Service Co. (formerly Arizona Nuclear Power RECIP.NAME RECIPIENT AFFILIATION Document Control Branch (Document Control Desk) R

SUBJECT:

Application for amend to license NPF-5l,allowinq functional testing of'hydraulic 'snubbers in facility to be performed during upcoming facility refueling outage.

D DISTRIBUTION CODE: AOOID TITLE: OR COPIES RECEIVED:LTR Submittal: General Distribution J ENCL J SIZE:

NOTES:Standardized plant. 05000529 RECIPIENT COPIES RECIPIENT COPIES ID CODE/NAME LTTR ENCL ID CODE/NAME LTTR ENCL D PD5 LA 1 1 PD5 PD 1 1 TRAMMELL,C 2 2 THOMPSON,M 2 2 D INTERNAL: ACRS 6 6 NRR/DET/ECMB 9H 1 1 NRR/DET/ESGB 1 1 NRR/DOEA/OTSB1 1 1 1 NRR/DST 8E2 1 . 1 NRR/DST/SELB 8D 1 1 NRR/DST/SICB8H3 1 1 NRR/DST/SRXB 8E 1 1 NUDOCS-ABSTRACT 1 1 1 0 OGC/HDS1 1 0 EG FIL 01 1 1 RES/DSIR/EIB 1, 1 EXTERNAL: NRC PDR 1 1 NSIC 1 " 1 NOTES: 1 1 D

D D

NOTE TO ALL "RIDS" RECIPIENTS:

PLEASE HELP US TO REDUCE WASTE! CONTACT THE DOCUMENT CONTROL DESK, ROOM Pl-37 (EXT. 20079) TO ELIMINATEYOUR NAME FROM DISTRIBUTION LISIS FOR DOCUMENTS YOU DON'T NEED!

TOTAL NUMBER OF COPIES REQUIRED: LTTR 27 ENCL 25

'\

0 T, J P

Arizona Public Service Company P.O, BOX 53999 ~ PHOENIX, ARIZONA85072<999 WILLIAMF. CONWAY 161-03982-WFC/MEP/DAF EXECUTIVEVICEPRESIDENT NUCLEAR May 29, 1991 Docket No. STN 50-529 U. S. Nuclear Regulatory Commission Attn: Document Control Desk Mail Station Pl-37 Washington, D. C. 20555

References:

1) Letter from J. G. Haynes (APS) to J. B. Martin (NRC),

161-00469-JGH/JRP, dated August 31, 1987

2) Letter from D. B. Karner (APS) to NRC, 161-01612-DBK/BJA, dated January 12, 1989

Dear Sirs:

Sub j ect: Palo Verde Nuclear Generating Station (PVNGS)

Unit 2 Proposed Technical Specification Change to Snubber Functional Testing File: 91-005-419.05 In accordance with 10 CFR 50.90, Arizona Public Service Company (APS) submits herewith a request to amend Facility Operating License NPF-51 for PVNGS Unit 2.

The proposed amendment will allow the functional testing of hydraulic snubbers in Unit 2 to be performed during the upcoming Unit 2 refueling outage. Current snubber functional testing requirements in Technical Specification 3/4.7.9 (due no later than September 25, 1991) would force the Unit to shutdown just prior to the planned refueling outage, currently scheduled to begin October 17, 1991.

The proposed amendment would extend the surveillance test interval by approximately one month to coincide with the upcoming Unit 2 refueling outage (scheduled to begin October 17, 1991), but not extend the testing interval beyond December 17, 1991. This three month window of time is sufficient for completing the snubber functional testing. Therefore, in order to preclude an unplanned shutdown in Unit 2, APS requests NRC approval of this amendment before September I

25, 1991.

Enclosed within this amendment request are:

A. Description of the Proposed Amendment Request B. Purpose of Technical Specification C. Need for Technical Specification Amendment 9iobo50312 910529= 05000529 PDR ',ADOCK PDR

161-03982-WFC/MEP/DAF May 29, 1991 Document Control Desk U. S. Nuclear Regulatory Commission Snubber Functional Testing Page Two D. No Significant Hazards Consideration Determination E. Safety Analysis of the Proposed Amendment Request F. Environmental Impact Consideration Determination G. Marked-Up Technical Specification Change Pages Pursuant to 10 CFR 50.91(b)(1), and by copy of this letter and attachment, we have notified the Arizona Radiation Regulatory Agency of this request for a Technical Specification change.

If you should have any questions, please contact Michael E. Powell of my staff at (602) 340-4981.

Sincerely, WFC/MEP/DAF/pmm Enclosure cc: J. B. Marti'n D. H. Coe C. F. Tedford A. C. Gehr A. H. Gutterman

1 1 161-03982-WFC/MEP/DAF May 29, 1991 STATE OF ARIZONA )

) ss.

COUNTY OF MARICOPA )

I, W. F. Conway, represent that I am Executive Vice President Nuclear, that the foregoing document has been signed by me on behalf of Arizona Public Service Company with full authority to do so, that I have read such document and know its contents, and that to the best of my knowledge and belief, the statements made therein are true and correct.

W. F. Conway Sworn To Before Me This Day Of 1991.

Public My Commission Expires

'I fI 1

t 61-03982-MFC/MEP/DAF May 29, 1991 ENCLOSURE A. DESCRIPTION OF THE PROPOSED AMENDMENT This amendment seeks to extend the testing frequency for Unit 2 hydraulic snubbers at PVNGS by allowing a one time extension to the current 18 month surveillance requirement plus the additional 25% allowed by section 4.0.2.

This proposed Technical Specification change, in the form of a footnote to Surveillance Requirement 4.7.9e (Functional Tests), would allow functional testing for the snubbers, currently done no later than September 25, 1991, to be deferred until the next refueling outage, but not beyond December 17, 1991.

B. PURPOSE OF THE TECHNICAL SPECIFICATION All snubbers are required to be operable to ensure that the structural integrity of the reactor coolant system and all other safety-related systems is maintained during and following a seismic or other event initiating dynamic loads. Snubbers excluded from the Technical Specification inspection program are those installed on nonsafety-related systems and then only if their failure or failure of the system on which they are installed would have no adverse effect on any safety-related system.

C. NEED FOR THE TECHNICAL SPECIFICATION AMENDMENT This one time only extension to Surveillance Requirement 4.7.9e is needed since performance of the snubber surveillance test within the current testing interval would force the unscheduled shutdown of Unit 2 approximately one month prior to the planned start of the third refueling outage, currently scheduled for October 17, 1991. The previous Unit 2 snubber inspection was performed on November 11, 1989, during an unplanned outage and just prior to the second refueling outage. The second refueling outage, scheduled for 92 days, actually lasted 145 days. Since the testing interval in Surveillance Requirement 4.7.9e allows 18 months plus an additional 25% (i.e., 4.5 months) past the November date, the next functional testing would be required no later than September 25, 1991.

However, the unplanned outage length will result in the third outage starting just beyond this date, thus requiring an extension to the surveillance requirement.

D. NO SIGNIFICANT HAZARDS CONSIDERATION DETERMINATION (1) The Commission has provided standards for determining whether a significant hazards consideration exists as stated in 10 CFR 50.92.

A proposed amendment to an operating license for a facility involves no significant hazards consideration if operation of the facility in accordance with a proposed amendment, would no't: (1) Involve a significant increase in the probability or consequences of an accident previously'valuated; or (2) Create the possibility of a'

C new t 161-03982-MFC/MEP/DAF May 29, 1991 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 the amendment request follows:

Standard 1 - Involve a significant increase in the probability or consequences of an accident previously evaluated.

The snubbers for which this amendment request pertains, are located only on the Reactor Coolant Pumps (RCPs) and Steam Generators (SGs). There are 8 snubbers per unit located on the RCPs and 4 snubbers per unit. on the SGs, for a unit total of 12 hydraulic snubbers. The following specifications are for hydraulic snubbers at PVNGS:

~Te ~Ca acit Bore Fluid SG Snubbers Paul Munroe 650 kips 22 in Fyrquel (oil) gravity flow type reservoir RCP Snubbers Paul Munroe 850 kips 14 in GE 1154 (oil) pressurized reservoir In addition, the following Unit 2 hydraulic snubbers have previously been functionally tested successfully at PVNGS:

Q First Refueling (Prior to) Second Refueling (4/16/89) (11/11/89)

SG ¹2 east (S/N 1195) SG ¹2 west (S/N 1196)

RCP 2A east (S/N 658) RCP 2B east (S/N 663)

Per Surveillance Requirement 4.7.9e, sample inspection plan 2 was selected for PVNGS Unit 2 snubbers (see references 1 and 2) which requires that a representative sample of each type of snubber be functionally tested in accordance with Figure 4:7-1. However, this figure is not relevant for snubber types with populations less than 37. Therefore, for the purposes of RCP and SG hydraulic snubber testing, one SG and one RCP snubber are considered a representative sample based on their respective populations in the unit.

Accordingly, the Unit 2 hydraulic snubbers to be tested during the upcoming (third) refueling outage for Unit 2 are:

SG ¹1 west (S/N 1194)

RCP ¹1A west (S/N 661)

The surveillance history for Unit 2 hydraulic snubbers has shown that the snubbers tested at the first and second refueling (noted above) have successfully satisfied the functional test acceptance criteria from 2

Surveillance Requirement 4.7.9f as follows:

t 161-03982-WFC/MEP/DAF May 29, 1991 The snubber functional test verifies that:

1) Activation (restraining action) is achieved within the specified range in both tension and compression;

2) Snubber bleed, or release rate where required, is present in both tension and compression, within the specified range;

3) For mechanical snubbers, the force required to initiate or maintain motion of the snubber is within the specified range in both directions of travel; and

4) For snubbers specifically required not to displace under continuous load, the ability of the snubber to withstand load without displacement.

Units 1 and 3 have also met this criteria in previous functional tests.

Therefore, it can be stated that there have been no problems with hydraulic snubbers at Palo Verde.

In addition, the extension of time sought in this amendment request (approximately three months if functional testing is performed at the end of the requested extension) is not considered a sufficient duration of time to incur significant degradation or expose the snubbers to other hazards or conditions for which the snubbers could not function or for which the snubbers could be degraded. The snubber function is to maintain structural integrity of systems and thus mitigate the effects of any seismic event or accident described in Chapter 15 of PVNGS UFSAR. The extension of time sought in this amendment request will not degrade this capability.

Therefore, based on the discussion provided above, the proposed amendment request will not involve a significant increase in the probability or consequences of an accident previously evaluated.

Standard 2 - Create the possibility of a new or different kind of accident from any accident previously evaluated.

The snubbers alone have no function pertaining directly to plant operation and thus cannot be an accident initiator. The snubbers ensure that the structural integrity of the reactor coolant system and other safety related systems is maintained during and following a seismic or other event initiating dynamic loads. The proposed amendment will not alter the current design of the facility nor is the extension of time significant enough to create the possibility of a new or different kind of accident from any accident previously evaluated.

Standard 3 - Involve a significant reduction in a margin of safety.

The proposed amendment does not involve a significant reduction in the margin of safety, at PVNGS because the extension of time sought for snubber testing does not involve a change to safety limits, setpoints, or design margins.

~ 4 t 161-03982-WFC/MEP/DAF May 29, 1991 SAFETY ANALYSIS OF THE PROPOSED AMENDMENT RE VEST The proposed change allows a one time only extension to the current snubber functional testing interval in order that the testing can be performed during the upcoming refueling outage and thus prevent an unplanned outage.

Performing the currently required surveillance test within the existing interval would force the unit to shutdown. approximately one month prior to the scheduled start of the refueling outage on October 17, 1991.

Therefore, a footnote is proposed explaining that this testing can be deferred until the next refueling outage but. not beyond December 17, 1991.

In evaluating the safety significance of the proposed change, the history of hydraulic snubber inspections at PVNGS should be discussed. As mentioned previously, there are 12 hydraulic snubbers per unit, 8 located on the RCPs and 4 on the SGs. Per the sample inspection plan (discussed in Section D), one SG and one RCP snubber is required to be tested each surveillance interval. The previous snubber tests were reviewed for Units 1, 2, and 3 and it was concluded that every surveillance test performed on hydraulic snubbers (as directed by PVNGS procedure 73ST-9ZZ10, Functional Testing of Hydraulic Snubbers) has successfully satisfied the Technical Specification acceptance criteria of Surveillance Requirement 4.7.9f. Therefore it can be categorically stated that there has been no history of hydraulic snubber problems at PVNGS. (Mechanical snubbers are not involved in this amendment request since these have been previously tested).

The extension that this amendment seeks would allow a discreet amount of time, beginning from the start of the refueling outage until December 17, 1991. This testing could be performed anytime between October 17, 1991 (estimated sta'rt of the third refueling outage) and December 17, 1991.

This timeframe is not considered of sufficient duration to cause undue degradation or expose the snubbers to significant structural hazards. The snubber function of mitigating seismic effects on the RCP and SG systems as well as maintaining the systems structural integrity will not be compromised by allowing this extension on the testing interval.

Based on the discussions provided above, this proposed amendment request will not involve a significant increase in the probability or consequences of an accident previously evaluated.

The proposed amendment does not make any hardware changes to the facility.

In addition, the snubbers do not contribute directly to plant operations at PVNGS but rather serve to mitigate seismic or other events which initiate dynamic loads. With this function, the snubbers are not considered to be accident initiators. Therefore, the extension of time that is involved for this surveillance requirement is not considered a significant length of time to create the possibility of a new or different kind of accident from any accident previously evaluated.

In addition, the extension of time sought for snubber testing does not involve a change to safety limits, setpoints, or design margins. As such, this amendment request will not involve a significant reduction in a margin of safety at PVNGS.

r

~

~

~

E t 161-03982-MFC/MEP/DAF May 29, 1991 F. ENVIRONMENTAL IMPACT CONSIDERATION DETERMINATION APS has determined that the proposed amendment involves no change in the amount or type of any effluent that may be released offsite, and that there is no increase in individual or cumulative ocupational radiation exposure.

As such, operation of PVNGS Unit 2, in accordance with the proposed amendment, does not involve an unreviewed environmental safety question.

G. MARKED-UP TECHNICAL SPECIFICATION CHANGE PAGES See attached page 3/4 7-23 for Unit 2.

0

~ ~

~ ~

r