ML17313A461

Forwards Response to 980330 RAI Re RPV Integrity at Pvngs. Best-estimate Chemistry Data Provided in CEOG Rept CE NPSD-1039,Rev 2,did Not Change most-limiting Matl or Have Significant Effect on Welds of PVNGS RPVs

ML17313A461
Person / Time
Site:	Palo Verde
Issue date:	06/24/1998
From:	James M. Levine ARIZONA PUBLIC SERVICE CO. (FORMERLY ARIZONA NUCLEAR
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
102-04139-JML-S, 102-4139-JML-S, GL-92-01, GL-92-1, NUDOCS 9806300521
Download: ML17313A461 (18)

Text

CATEGORY 1 REGULA RY INFORMATION DISTRIBUTIO SYSTEM (RIDS)

ACCESSION NBR:980 FACIL:STN-50-528 STN-50-529 STN=50'-530 AUTH.NAME LEVINE,J.M.

RECIP.NAME 6300521 DOC.DATE: 98/06/24 NOTARIZED: NO DOCKET I Palo Verde Nuclear Station, Unit 1, Arizona Publi 05000528 Palo Verde Nuclear Station, Unit 2, Arizona Publi 05000529 Palo Verde Nuclear Station, Unit 3, Arizona Publi 05000530 AUTHOR AFFILIATION Arizona Public Service Co.

(formerly Arizona Nuclear Power RECIPIENT AFFILIATION Records Management Branch (Document Control Desk)

SUBJECT:

Forwards response to 980330 RAI re RPV integrity at PVNGS.

Best-estimate chemistry data provided in CEOG rept CE NPSD-1039,Rev 2,did not change most-limiting matl or have significant effect on welds of PVNGS RPVs.

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TITLE: OR Submittal: General Distribution NOTES: STANDARDIZED PLANT Standardized plant.

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NOTE TO ALL "RIDS" RECIPIENTS:

PLEASE HELP US TO REDUCE WASTE. TO HAVE YOUR NAME OR ORGANIZATION REMOVED FROM DISTRIBUTION LISTS OR REDUCE THE NUMBER OF COPIES RECEIVED BY YOU OR YOUR ORGANIZATION, CONTACT THE DOCUMENT CONTROL DESK (DCD)

ON EXTENSION 41S-2083 TOTAL NUMBER OF COPIES REQUIRED:

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Commltmnnt InnotrntlnrL&eyy.

Palo Verde Nuclear Generating Station James M. Levine Senior Vice President Nuclear.

TEL (602)393-5300 FAX(602)3934077 Mail Station 7602 P.O. Box 52034 Phoenbt, AZ 65072-2034 Generic Letter 92-01 102-04139-JMUSAB/RMW June 24, 1998 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Mail Station P1-37 Washington, DC 20555-0001

Subject:

Palo Verde Nuclear Generating Station (PVNGS)

Units 1, 2 and 3 Docket Nos. STN 50-528/529/530

Response

to Request for Additional Information Regarding Reactor Pressure Vessel Integrity at Palo Verde Nuclear Generating Station Enclosure 1

provides the additional information regarding reactor pressure vessel integrity at the Palo Verde Nuclear Generating Station that was requested in your letter

(

to Arizona Public Service'Company (APS) dated March 30, 1998.

As stated in the Enclosure, the best-estimate chemistry data provided in the Combustion. Engineering Owners Group (GEOG) Report, CE NPSD-1039, Revision 2, "Best Estimate Copper and Nickel Values in CE Fabricated Reactor Vessel Welds", did not change the most-limiting material.or have a signiricant effect on the weids of the PVNGS reactor pressure vessels.

This letter does not make any commitments to the NRC. Please contact Mr. Scott Bauer at (602) 393-5978 ifyou have any questions or would like additional information regarding this matter.

Sincerely, Enclosure JMUSAB/RMW/rlh cc:

E. W. Merschoff K. E. Perkins M. B. Fields J. H. Moorman

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ENCLOSURE 1 Response to Request for Additional Information Regarding Reactor Pressure Vessel Integrity at Palo Verde Nuclear Generating Station

NRC Re uest 1

(Please refer to NRC letter to APS, "Request for Additional Information regarding Reactor Vessel Integrity at Palo Verde Nuclear Generating Station (TAC Nos. MA0561, MA0562 and MA0563), dated March 30, 1998 for a full description of the requested information.)

Based on this information, in accordance with the provisions of Generic Letter 92-01, Revision 1, Supplement 1, the NRC requests the following:

An evaluation of the information in the reference above and an assessment of its applicability to the determination of the best-estimate chemistry for all of your RPV beltline welds.

Based upon this reevaluation, supply the information necessary to completely fill out the data requested in Table 1 for each RPV beltline weld material. Also provide a discussion for the copper and nickel values chosen for each weld wire heat noting what heat-specific data were included and excluded from the analysis and the analysis method chosen for determining the best-estimate.

Ifthe limiting material for your vessel's PTS/PT limits evaluation is not a weld, include the information requested in Table 1 for the limiting material also.

Furthermore, you should consider the information provided in Section 2.0 of this RAI on the use of surveillance data when responding.

APS Res onse APS has reviewed the data submitted under GEOG report, CE NPSD-1039, Revision 2, "Best Estimate Copper and Nickel Values in CE Fabricated Reactor Vessel Welds." The best-estimate chemistry data for the PVNGS reactor pressure vessel weld heats were reviewed for any potential impact on the current design basis assessments for reactor pressure vessel structural integrity and to ensure continued compliance with 10 CFR 50.60, 10 CFR 50.61 and 10 CFR 50 Appendices G and H. The PVNGS-specific data provided in this report were also reviewed to identify any potential impact to the current low-temperature over-pressure (LTOP) limits and pressure-temperature (PT) limits for the PVNGS reactor pressure vessels.

Table 1 lists current PVNGS-reported data for reactor pressure vessel beltline welds for nickel (Ni), copper (Cu), and the corresponding chemistry factor (CF), as listed in the NRC Reactor Vessel Industry Database (RVID). This information was provided to the NRC in previous APS submittals.

Table 1 also lists the recommended best-estimate chemistry for Ni and Cu, and corresponding heat numbers for the PVNGS reactor pressure vessel welds from Table 6.1 of GEOG report, CE NPSD-1039, Revision 2, and represents the preferred simple mean or weighted mean chemistry value for that heat.

This GEOG report does not address base metal chemistry.

APS calculated new CFs 1

using the same methodology that was utilized for the previous CF calculations.

These calculations were performed using the best-estimate chemistry data values for Ni and Cu that were provided in this GEOG report, with the exception that the new values for Cu were rounded off as appropriate for these calculations.

The new CFs are listed in Table 1.

As shown in the table, the best-estimate chemistry values for Cu from this GEOG report are lower than, or equivalent to, the previous Cu values submitted by APS to the NRC.

Therefore, there was no impact on the PVNGS reactor pressure vessel beltline welds end-of-life (EOL) upper shelf energy (USE) predictions (reference Reg. Guide 1.99, Revision 2, Section 1.2) as a result of this new information.

Since the new best-estimate data did not affect the results of the previous analyses for the reactor pressure vessel beltline welds, the most limiting material continues to be Unit 1 intermediate shell plate material, M-6701-1, which has an EOL USE of 65 ft-Ibs at 1/4t.

The chemistry data previously submitted by APS for this material is considered to be valid and is based on certified material test reports data.

As stated previously, APS has calculated new chemistry factors based on the best-estimate data for Ni and Cu that were provided in GEOG report, CE NPSD-1039, Revision 2. The results from these calculations have determined that the CFs are lower for all but three welds. An assessment of the change in CFs on the adjusted reference temperature (ART) calculations for these non-limiting welds is illustrated in Table 2. For comparison, information regarding the current limiting reactor pressure vessel material for PVNGS is also provided in this Table.

Comparing the most limiting material to the revised values for ART and un-irradiated USE of the affected welds demonstrate that the Unit 1 intermediate shell plate continues to be the most limiting material for the PVNGS reactor pressure vessels.

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Table 1. Palo Verde Reactor Vessel Chemistry Data UnitlSeam No.

UNIT 1 INTERMEDIATE SHELL AXIAL WELDS 101-124 A,B,C

Heat, Number (Note 1, Page 4I 4P6052 NRC Reactor,'essel Indust'ry Database Ni Value 0.03 NRC,"",,'.;.

Reactor Vessel

Industry, Database

'u Value

'.07

,',C EN P., SD',

',1039,Rev.

2 Table,6.1,

,'Ni-Value

'.049 CENPSD

-1039,',,

,'ev.,2

Table 6.1 Cu Value 0.047 NRC Reactor Vessel Industry Database Chemistry Factor 35.45 APS-Calculated New Chemistry Factor (Note 2, Pa e4 31.64 UNIT 1 4P7869 CIRCUMFERENTIAL WELD 101-171 0.07 0.05 0.096 0.031 34.05 28.24 UNIT 1 LOWER SHELL AXIALWELDS 101-142 A,B,C UNIT2 INTERMEDIATE SHELL AXIAL WELDS 101-124 A,B,C 90071 89833 0.04 0.04 0.04 0.06 0.079 0.059 0.035 0.046 27.8 33.6 31.05 32.79 UNIT2 4P7869 CIRCUMFERENTIAL WELD 101-171 0.07 0.03 0.096 0.031 26.55 28.24 UNIT2 LOWER SHELL AXIALWELDS 101-142 A,B,C UNIT3 INTERMEDIATE SHELL AXIAL WELDS 101-124 A,B,C 3P7317 4P7869 0.04 0.06 0.09 0.03 0.067 0.096 0.074 0.031 44.20 25.9 43.37 28.24 UNIT3 4P7869 CIRCUMFERENTIAL WELD 101-171 0.07 0.05 0.096 0.031 34.05 28.24 UNIT3 LOWER SHELL AXIALWELDS 101-142 A,B,C 4P7869 0.07 0.04 0.096 0.031 30.65 28.24

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Table 2 - Assessment of Increased CFs on Adjusted Reference Temperature

lWeld, Identification:..".'NIT 1

LOWER SHELL AXIALWELDS 101-142 A,B,C

~,'Heat Number 90071

NRC

, Reactor, Vessel I I

,Database, iARTI 32.98

,Calculated'...

'"ART

,Using New:,,

'eg.'uide

'1.99,,Rev. 2 37.25 Un-irradiated'USE ';

140 UNIT2 4P7869 CIRCUMFERENTIAL WELD 101-171 39.66 41.88 95 UNIT3 INTERMEDIATE SHELL AXIAL WELDS 101-124 A,B,C 4P7869 18.19 21.03 100 LIMITINGMATERIAL NAIPL-A UNIT 1 INTERMEDIATE SHELL PLATE M701-1 61.73 N/A 83 Notes to Table 1:

1.

The heat numbers provided in this Table for the beltline welds may not coincide with the heat numbers provided in the Reactor Vessel Industry Database.

Please update the RVID as appropriate to reflect the revised heat numbers.

2.

New CF calculated using the best-estimate chemistry data from CE NPSD-1039, Revision 2.

The value for Cu was rounded off, as appropriate, for this calculation.

Notes to Table 2:

None

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NRC Re uest 2 (Please refer to NRC letter to APS, "Request for Additional Information regarding Reactor Vessel Integrity at Palo Verde Nuclear Generating Station (TAC Nos. MA0561, MA0562 and MA0563), dated March 30, 1998 for a full description of the requested information.)

Based on this information and consistent with the provisions of Generic Letter 92-01, Revision 1, Supplement 1, the NRC requests the following:

that (1) the information listed in Table 2, Table 3, and the chemistry factor from the surveillance data be provided for each heat of material for which surveillance weld data are available and a revision in the RPV integrity analyses (i.e., current licensing basis) is needed or (2) a certification that previously submitted evaluations remain valid.

Separate tables should be used for each heat of material addressed.

If the limiting material for your vessel's PTS/PT limits evaluation is not a weld, include the information requested in the tables for the limiting material (ifsurveillance data are available for this material).

APS Res onse APS does not currently utilize reactor vessel surveillance data as a consideration in evaluating LTOP limits, PT limits or pressurized thermal shock (PTS) calculations.

Therefore, the best-estimate chemistry data presented in the GEOG Report, CE NPSD-1039, Revision 2, as it pertains to reactor pressure vessel surveillance specimens, do not apply to these limits or calculations.

t Based on APS review of the information provided in GEOG report CE NPSD-1039, Revision 2, APS hereby certifies that the limiting material for the PVNGS reactor pressure vessels has not changed and that the previously submitted calculations for PTS and PT limits remain valid..

NRCRe uest3 (Please refer to NRC letter to APS, "Request for Additional Information regarding Reactor Vessel Integrity at Palo Verde Nuclear Generating Station (TAC Nos. MA0561, MA0562 and MA0563), dated March 30, 1998 for a full description of the requested information.)

3.

If the limiting material for your plant changes or if the adjusted reference temperature for the limiting material increases as a

result of the above evaluations, provide the revised RT,7$

value for the limiting material in accordance with 10 CFR 50.61.

In addition, if the adjusted RTNpT value increased, provide a schedule for revising the PT and LTOP limits.

The schedule should ensure that compliance with 10 CFR 50 Appendix G

is maintained.

APS Res onse The limiting material for the PVNGS reactor pressure vessels has not changed.

As stated in the APS response to NRC Request 2, the previously submitted calculations for determining LTOP and PT limits remain valid.

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Su~~arur As shown above, APS considered the best-estimate chemistry data presented in the GEOG report, CE NPSD-1039, Revision 2, "Best Estimate Copper and Nickel Values in CE Fabricated Reactor Vessel Welds" as it pertains to the structural integrity of the PVNGS reactor pressure vessels.

Of the nine weld locations that were potentially affected by the best-estimate chemistry data provided in the GEOG report, six weld locations were determined to have lower corresponding CFs.

Therefore, the current data, as listed in the RVID, for these welds remains valid and is conservative.

The three weld locations that have slightly higher calculated CFs remain non-limiting with respect to the PVNGS reactor pressure vessels.

The EOL USE values for these welds were not affected by the updated chemistry data provided in the GEOG report.

Therefore, the most limiting material for the PVNGS reactor pressure vessels continues to be the Unit 1 intermediate shell plate, M-6701-1.

APS concludes that the information provided in GEOG report, CE NPSD-1039, Revision 2,

did not significantly impact the current APS design basis calculations and assessments for reactor vessel structural integrity, nor did it affect the previously submitted calculations for LTOP or PT limits. The calculations for LTOP and PT limits are based on the most-limiting material for the PVNGS reactor pressure vessels, which is Unit 1

intermediate shell plate, M-6701-1.

This material remains limiting after considering the data provided in the CEOG report for best-estimate weld chemistries.

In

addition, the information provided in this GEOG report did not affect PVNGS compliance with 10 CFR 50.60, 10 CFR 50.61, and 10 CFR 50 Appendices G and H.

No revisions to the RVID, other than revising the heat numbers for the beltline welds as shown in Table 1,

are required for the PVNGS reactor pressure vessel data.

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