ML081290455

Letter from Alex S. Polonsky Informing the Commission That on May 1, 2008, Amergen Submitted the Enclosed Response to NRC Request for Additional Information on Metal Fatigue Analysis Related to Oyster Creek

ML081290455
Person / Time
Site:	Oyster Creek
Issue date:	05/05/2008
From:	Polonsky A AmerGen Energy Co, Morgan, Morgan, Lewis & Bockius, LLP
To:	Klein D NRC/Chairman
SECY RAS
References
50-219-LR, FOIA/PA-2008-0306, RAS H-19, TAC MC7624
Download: ML081290455 (12)

Text

Y-17 Morgan, Lewis &Bockius LLP 1111 Pennsylvania Avenue, NW Washington, DC 20004 Morgan Lewis COUNSELORS AT LAW Tel: 202.739.3000 Fax: 202.739.3001 www.morganlewis.com DOCKETED USNRC Alex S. Polonsky May 6, 2008 (9:00am) 202.739.5830 apolonskvy.morganlewis.com OFFICE OF SECRETARY RULEMAKINGS AND ADJUDICATIONS STAFF VIA ELECTRONIC MAIL AND FIRST CLASS MAIL May 5, 2008 The Honorable Dale E. Klein CHairman U.S. Nuclear Regulatory Commission Washington, D.C. 20555-0001 Re: In the Matter of AmerGen Energy Company, LLC (License Renewal for Oyster Creek Nuclear Generating Station) Docket No. 50-219-LR

Dear Chairman Klein:

The purpose of this letter is to inform the Commission that, on May 1, 2008, AmerGen Energy Company, LLC ("AmerGen") submitted the enclosed Response to NRC Request for Additional Information on Metal Fatigue Analysis Related to Oyster Creek Nuclear Generating Station License Renewal Application (TAC No. MC7624) ("RAI"). A copy of AmerGen's Response to the RAI is enclosed for your information. Copies of the Response also have been sent by e-mail and first class mail to those parties identified in the service list for this proceeding.

Sincerely,

/62 Alex S. Polonsky Counsel for AmerGen Energy Company, LLC

Enclosure:

As stated cc w/encl.: Service List I-WA/2969588.

TE PL KC-y 0c3

UNITED STATES OF AMERICA NUCLEAR REGULATORY COMMISSION BEFORE THE COMMISSION

)

In the Matter of: ) May 5, 2008

)

AmerGen Energy Company, LLC )

) Docket No. 50-219 (License Renewal for Oyster Creek Nuclear )

Generating Station) )

CERTIFICATE OF SERVICE I hereby certify that copies of a letter from counsel for AmerGen Energy Company, LLC

("AmerGen") to the Honorable Dale E. Klein, Chairman, U.S. Nuclear Regulatory Commission, dated May 5, 2008, were served this day upon the persons listed below, by e-mail and first class mail. The letter forwards a copy of AmerGen's Response to NRC Request for Additional Information on Metal Fatigue Analysis Related to Oyster Creek Nuclear Generating Station License Renewal Application (TAC No. MC7624).

Secretary of the Commission* Administrative Judge U.S. Nuclear Regulatory Commission Paul B. Abramson Attn: Rulemakings and Adjudications Staff Atomic Safety and Licensing Board Panel One White Flint North Mail Stop: T-3 F23 11555 Rockville Pike U.S. Nuclear Regulatory Commission Rockville, Maryland 20852-2738 Washington, DC 20555-0001 (E-mail: HEARINGDOCKET(inrc.gov) (E-mail: pbamnrc.gov)

Administrative Judge Office of Commission Appellate E. Roy Hawkens, Chair Adjudication Atomic Safety and Licensing Board Paneel U.S. Nuclear Regulatory Commission Mail Stop: T-3 F23 Washington,-DC -20555- 0001 .

U.S. Nuclear Regulatory Commission (E-mail: OCAAmail(anrc.gov)

Washington, DC 20555-0001 (E-mail: erh(@nrc.gov)

I-WA/2969562.1

Administrative Judge John A. Covino Anthony J. Baratta Valerie Anne Gray Atomic Safety and Licensing Board Panel Division of Law Mail Stop: T-3 F23 Environmental Permitting and Counseling U.S. Nuclear Regulatory Commission Section Washington, DC 20555-0001 P.O. Box 093 (E-mail: aib5(@nrc.gov) Hughes Justice Complex Trenton, NJ 08625 (E-mail: john.covinoidol.lps.state.ni.us)

(E-mail: valerie.grayv(dol.lps.state.nj.us)

Richard Webster Suzanne Leta Julia LeMense NJPIRG Eastern Environmental Law Center 11 N. Willow Street 744 Broad Street, Suite 1525 Trenton, NJ 08608 Newark, NJ 07102 (E-mail: sleta(anipirg.org)

(E-mail: rwebster-eastemenvironmental.org)

(E-mail: ilemense(ýeastemenvironmental.org)

Paul Gunter Emily Krause Kevin Kamps Law Clerk Beyond Nuclear Atomic Safety and Licensing Board 6930 Carroll Avenue Mail Stop: T-3 F23 Suite 400 U.S. Nuclear Regulatory Commission Takoma Park, MD 20912 Washington, DC 20555-0001 (E-mail: paulabeyondnuclear.org) (E-mail: eikl (o)nrc.gov)

(E-mail: kevin(beyondnuclear.org)

Mary C. Baty Kimberly A. Sexton James E. Adler Office of the General Counsel, 0-15D21 U.S. Nuclear Regulatory Commission Washington, DC 20555_

(E-mail: kas2(@,nrc.gov)

(E-mail: mcb 1 nrc.gov)

(E-mail: jeal (@nrc.gov)

• Original and 2 copies Aaphaýyl^utyler I-WA/2969562.1 2

Michael P. Gallaghey, PE Telephone 610.765.5958 AmerGen.

An Exelon Company Vice President www.exeloncorp.com License Renewal Projects mfchaelp.gailagher@exeloncorp.com 10 CFR 50 ArnerGen 10 CFR 51 200 Exelon Way KSA/2-E 10 CFR 54 Kennett Square, PA 19348 RA 08-046 May 1, 2008 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555 Oyster Creek Generating Station Facility Operating License No. DPR-16 NRC Docket No. 50-219

Subject:

Response to NRC Request for Additional Information on Metal Fatigue Analysis Related to Oyster Creek Generating Station License Renewal Application (TAC No. MC7624)

Reference:

NRC Request for Additional Information, dated April 29, 2008, Related to Oyster Creek Generating Station License Renewal Application (TAC No. MC7624)

In the referenced letter, the NRC requested AmerGen Energy Company, LLC (AmerGen) to provide additional information related to fatigue analysis performed in support of license renewal for Oyster Creek Generating Station (OCGS). This information was requested in the form of two questions, RAI 4.3.4-1 and RAI 4.3.4-2. The Enclosure to this letter provides AmerGen's response to these requests.

If you have any questions, please contact Fred Polaski, Manager License Renewal, at 610-765-5935.

I declare under penalty of perjury that-the foregoing is true and correct.

Respectfully, Executed on 05"-0 1 - 1005 Michael P. Gallagher Vice President, License Renewal AmerGen Energy Company, LLC

Enclosure:

Response to RAIs 4.3.4-1 and 4.3.4-2

May 1, 2008 Page 2 of 2 cc: Regional Administrator, USNRC Region I USNRC Senior Project Manager, NRR - License Renewal, Safety USNRC Project Manager, NRR - License Renewal, Environmental USNRC Project Manager, NRR - OCGS USNRC Senior Resident -Inspector, OCGS Bureau of Nuclear Engineering, NJDEP File No. 05040

ENCLOSURE RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION RELATED TO OYSTER CREEK GENERATING STATION LICENSE RENEWAL APPLICATION FATIGUE ANALYSIS RAI 4.3.4-1

- Attachment I

- Attachment 2

- Attachment 3 RAI 4.3.4-2

'Enclosure Page 2 of 7 RAI 4.3.4-1 The staff identified a concern regarding the methodology used by license renewal applicants to demonstrate the ability of nuclear power plant components to withstand the cyclic loads associated with plant transient operations for the period of extended operation. The analysis methodology of concern focused on the use of a Greens function to calculate stresses used in calculating the fatigue cumulative usage factor (CUF). It involves a simplified input for applying the Green's function in which only one value of stress is used to represent the stress field of actual plant transients. The use of this methodology requires a great deal of engineering judgment by the analyst to assure the simplification still provides conservative results. The staff understands that this methodology was used to calculate the environmentally impacted CUF for the Oyster Creek reactor recirculation outlet nozzle. The staff requests that OGCS perform an additional stress analysis of the recirculation outlet nozzle in accordance with the ASME Code,Section III, Subsection NB-3200 methodology (all six stress components are retained in the analysis) to confirm that the results of the previous Green's function evaluation is acceptable.

Provide a summary of the results which includes the following information:

• A comparison of the calculated stresses and fatigue usage factors using the Green's function evaluation and the additional confirmatory analysis for each plant transient and transient pairs that contributed to the CUF.

0 The environmental factor, Fan, used to evaluate each transient pair.

• A discussion of any differences in the analysis input parameters and analysis assumptions between the Green's function evaluation and the confirmatory analysis.

Response to RAI 4.3.4-1 AmerGen has performed confirmatory fatigue analysis of the Oyster Creek Generating Station (OCGS) reactor pressure vessel (RPV) recirculation outlet nozzle in accordance with the ASME Code,Section III, Subsection NB-3200 methodology, utilizing all six components of stress in the analysis. This new analysis confirms that the results of the original analysis are conservative and remain acceptable.

Table 1 compares the CUF and environmentally assisted fatigue (EAF) CUF results from the original analysis with those from the new analysis.

. . . . Table I i-Summar of-Fatigue- Usage-Results (60 Years)

Nozzle Original 0.1832 5.34 0.9781 Corner New 0.0207 6.60 0.1366

Enclosure Page 3 of 7 The input parameters and assumptions used in the original analysis and the new analysis are essentially the same with the exception of those described in the four notes below. In order to facilitate NRC review, this new analysis was prepared using assumptions similar to those made by a recent applicant also performing a confirmatory analysis. It was not the intent of the new analysis to duplicate the results of the original analysis, nor was it the intent to'remove conservatism. Rather, the objective was to develop an independent ASME Code,Section III, Subsection NB-3200 fatigue calculation for the OCGS recirculation outlet nozzle using standard analytical methods and conventions previously accepted by the NRC to determine whether or not the original analysis results were conservative. The following notes describe how the new analysis differs from the original analysis:

1. In the new analysis, all six components of stress were extracted from finite element analysis of all transients, which were then utilized in calculating fatigue usage factor per NB-3216.2 of Section III of the ASME Code. No Green's functions were used.

Calculated stresses are comparable and CUF is lower.

2. In the new analysis, the nozzle cladding was neglected for the fatigue calculation, as permitted in NB-3122.3 of Section III of the ASME Code, and the base metal was evaluated for stresses and fatigue usage. This is consistent with the method used by a recent applicant that performed a confirmatory analysis for one RPV nozzle, and is also consistent with the approach used in NUREG/CR-6260 for several component evaluations. In the original analysis for the OCGS recirculation outlet nozzle, stresses were conservatively extracted on the stainless steel cladding surface and were evaluated using the carbon steel fatigue curve, which provided very conservative fatigue usage results.

3. For the Emergency Condenser transients in the new analysis, a 10,000 second hold time was assumed between the initial downward shock in temperature and the subsequent warm-up. The original analysis did not include this hold time based on plant-specific transient evaluation. This change was made to conservatively assure that the peak stress is captured after the downward shock and address all possible scenarios of event severity for future plant operation. This change resulted in a higher stress for these transients in the new analysis, but this increase in stress was an insignificant contributor to fatigue usage compared to the decrease in fatigue usage described by note 2 above.

4. For the new EAF analysis, detailed F,, multipliers were determined for each load pair based on maximum transient temperatures with assumed low strain rates, resulting in a maximized strain rate term for each of these Fen multipliers. In the original EAF analysis,

..... detailed Fen multipliers were determined for each load pair based upon both maximum - -

transient temperatures and calculated strain rates. This change was made to eliminate any possible non-conservatism in determining the strain rates and the resultant environmental fatigue multipliers for the new analysis, and to be consistent with the method used in a confirmatory analysis performed by another recent applicant. This change resulted in an increase in the overall Fen multiplier for the OCGS recirculation outlet nozzle in the new analysis.

Attachment I shows information from the original analysis, including the calculated stress, fatigue CUF, Fen multipliers, and EAF CUF values for each transient pair. Attachment 2 provides the same information from the new analysis for comparison with Attachment 1. provides the transient descriptions and number of cycles associated with the transient numbers shown in both Attachment 1 and Attachment 2.

Enclosure Page 4 of 7 In conclusion, the original OCGS recirculation outlet nozzle EAF analysis was developed using a simplified method that utilized Green's functions to compute thermal transient stresses in which only one value of stress was used to represent the stress field. The new analysis confirms that the results of the original analysis are conservative and remain acceptable.

RAI 4~3.4-2 Confirm the reactor recirculation outlet nozzle was the only location where the Green's function (simplified calculation methodology) methodology was used to evaluate the fatigue CUF for license renewal.

Response to RAI 4.3.4-2 The reactor recirculation outlet nozzle was the only location where the Green's function methodology (simplified calculation methodology) was used to evaluate the fatigue CUF for OCGS license renewal.II

Original Analysis Chemistry Mode: HWC NWC DO concentration: 1 180 ppb

% of Time: 59% 41%

Trrie t-Vraigient S~i iWC.~4 ~

2 5 42,663 ... 1 7,093 0.0001 1.18E-03 -6.739 525.0 273.9 2.45 16.45 0.0012 2 3 86,760 245 7,095 0.0345 2.41 E-03 -6.029 525.0 273.9 2.45 13.46 0.2406 10 3 86,114 68 ,7,254 0.0094 5.68E-05 -6.908 427.0 219.4 2.45 7.32 0.0417 10 1 86,083 35 7,261 0.0048 5.68E-05 -6.908 427.0 219.4 2.45 7.32 0.0215 11 1 86,083 237 7,261 0.0326 5.68E-05 -6.908 427.0 219.4 2.45 7.32 0.1453 11 4 85,945 1 i*7,296 0.0001 5.67E-05 -6.908 427.0 219.4 2.45 7.32 0.0006 11 1 84,502 179 7,672 0.0233 5.57E-05 -6.908 427.0 219.4 2.45 7.32 0.1038 2 1 84,294 93 '7,728 0.0120 5.55E-04 -6.908 525.0 273.9 2.45 17.25 0.1026 2 9 65,037 153, 17,990 0.0085 4.28E-04 -6.908 525.0 273.9 2.45 17.25 0.0725 10 9 64,260 95 18,740 0.0051 2.14E-04 -6.908 427.0 219.4 /2.45 7.32 0.0226 10 9 58,694 8 " 24,910 0.0003 .1.96E-04 -6.908 427.0 219.4 2.45 7.32 0.0014 11 9 58,685 .240 24,920 0.0096 1.96E-04 -6.908 427.0 219.4 2.45 7.32 0.0429 11 9 58,465 177 25,210 0.0070 1.95E-04 -6.908 427.0 219.4 2.45 7.32 0.0312 11 9 58,156 71 25,630 0.0028 6.07E-04 -6.908 427.0 219.4 2.45 7.32 0.01 23 11 9 57,879 248 i26,000 0.0095 I6.04E-94 -6.908 427.0 219.4 2.45 7.32 0.0425 11 9 57,879 98 26,000 0.0038 6.04E-04 -6.908 427.0 219.4 2.45 7.32 0.0168 10 9 57,850 103 26,040 0.0040 7.59E-04 -6.908 427.0 219.4 2.45 7.32 0.0176 10 9 57,748 47 26,180 0.0018 4.28E-03 -5.454 359.8 182.1 2.45 3.66 0.0053 10 9 57,748 56 26,180 0.0021 4.28E-03 -5.454 359.8 182.1 2.45 3.66 0.0063 10 9 57,697 103 !26,260 0.0039 2.52E-03 -5.983 427.0 219.4 2.45 6.33 0.0159 2 9 57,642 89 26,330 0.0034 2.63E-02 -3.637 544.7 284.9 2.45 7.51 0.0153 2 5 52,234 1 35,630 0.0000 2.39E-02 -3.736 544.7 284.9 2.45 7.74 0.0001 2 5 51.359 1 37,530 0.0000 2.35E-02 -3.753 544.7 284.9 2.45 7.78 0.0001 2 9 44,354 155 i 65,080 0.0024 2.03E-02 -3.899 544.7 284.9 2.45 8.14 0.0114 11 9 44,301 93 i65,470 0.0014 3.41E-03 -5.681 390.7 199.3 2.45 4.64 0.0048 11 12 25,420 324 11,001,000 0.0003 1.96E-03 -6.236 390.7 199.3 2.45 4.94 0.0011 11 12 25,410 196 1,006,000 0.0002 1.38E-03 -6.589 427.0 219.4 2.45 6.96 0.0008 Total, Uwo = 0.1832 Total, U6 0-eny = 0.9781 Definitions: 5.34 Overall F., =

Transient 1 = transient number for first transient in'load pair.

Transient 2 = transient number for second transient in load pair.

Salt = alternating stress in psi.

n = number of applied cycles for load pair.

Nallow = allowable number of cycles for Salt from ASME Code Section III fatigue curve.

U = incremental fatigue usage for load pair, nINallow.

Strain rate e-dot (%) = tensile strain rate for load pair (%).

e-dot* = transformed strain rate computed in accordance with NUREG/CR-6583.

TMAX = maximum metal temperature for load pair (*F or °C).

HWC Fen: Fen multiplier computed in accordancewith NUREG/CR-6583 for hydrogen water chemistry (HWC) conditions.

NWC Fen: Fen multiplier computed in accordance with NUREG/CR-6583 for normal water chemistry (NWC) conditions.

Uenv: Environmentally assisted fatigue usage factor, computed as (NWC Fen x 0.41 = HWC Fen x 0.59) x U.

New Analysis Chemistry Made: HWC NWC DO Concentration: 1 180 ppb Definitions:

Transient 1,= transient number for first transient in load pair.

Transient 2 = transient number for second transient in load pair.

Salt = alternating stress in psi.

n = number of applied cycles for load pair.

Nallow = allowable number of cycles for Salt from ASME Code Section III fatigue curve.

U = incremental fatigue usage for load pair, n/Nallow.

TMAX = maximum metal temperature for load pair .(°F or °C).

HWC Fen: Fen multiplier computed in accordance with NUREG/CR-6583 for hydrogen water chemistry (HWC) conditions.

NWC Fen: Fen multiplier computed in accordance,'with NUREG/CR-6583 for normal water chemistry (NWC) conditions.

Uenv: Environmentally assisted fatigue usage factor, computed as (NWC Fen x 0.41 = HWC Fen x 0.59) x U.

/

Attachment 3: Transient Descriptions Notes: For the original analysis, these transients were grouped with the Shutdown Transient.

For original analysis, 103 cycles of Emergency Condenser Initiation and 417 cycles of Emergency Condenser Subsequent Actuation were conservatively evaluated, compared to 77 cycles and 443 cycles, respectively, in the new analysis.