ML061660072

2006/06/12-Supplement to Amergen Response to NRC Request for Additional Information RAI 4.3-4, Related to Oyster Creek License Renewal Application

ML061660072
Person / Time
Site:	Oyster Creek
Issue date:	06/12/2006
From:	Gallagher M P AmerGen Energy Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
%dam200612, 2130-06-20349, TAC MC7624
Download: ML061660072 (6)

Text

AmerGen SM Michael P. GallagheT, PE Vice President License Renewal Projects AmerGen 2oo Exelon Way KSA/2-E Kennett Square. PA 19348 Telephone 610.765.5958 www.exeloncorp.com michaelp.gallagher@exeloncorp.com An Exelon Company 10 CFR 50 10 CFR 51 10 CFR 54 2130-06-20349 June 12, 2006 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

Reference:

Supplement to AmerGen Response to NRC Request for Additional Information RAI 4.3-4, Related to Oyster Creek Generating Station License Renewal Application (TAC No. MC7624)May 1, 2006 AmerGen Response to NRC Request for Additional Information, dated March 30, 2006, Related to Oyster Creek Generating Station License Renewal Application (TAC No. MC7624)In the referenced letter, AmerGen responded to NRC Request for Additional Information (RAI)4.3-4. During the NRC Staff review of this response, it was determined that a clarification to the response was needed. The Enclosure to this letter provides that clarification.

Question RAI 4.3-4 along with the original response is repeated.

New information included in the response is displayed in bold font for ease of identification.

An exception to this convention is that information bolded in Table 4.3.4-1 of the original response remains bolded. No new information has been introduced into that Table.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 06o I-l-"oo6 Michael P. Gallagher Vice President, License Renewal AmerGen Energy Company, LLC

Enclosure:

Clarification to RAI 4.3-4 Response PC 114 June 12, 2006 Page 2 of 2 cc: Regional Administrator, USNRC Region I, w/o Enclosure USNRC Project Manager, NRR -License Renewal, Safety, w/Enclosure USNRC Project Manager, NRR -License Renewal, Environmental, w/o Enclosure USNRC Project Manager, NRR -OCGS, w/o Enclosure USNRC Senior Resident Inspector, OCGS, w/o Enclosure Bureau of Nuclear Engineering, NJDEP, w/Enclosure File No. 05040 ENCLOSURE CLARIFICATION TO RAI 4.3-4 RESPONSE RELATED TO OYSTER CREEK GENERATING STATION LICENSE RENEWAL APPLICATION June 12, 2006 Supplement Page 1 of 4 RAI 4.3-4 Section 4.3.4 of the license renewal application discusses the evaluation of the effects of the reactor coolant environment on the fatigue life of components and piping. Table 4.3.4-1 provides the overall environmental fatigue multipliers for the components analyzed.

Provide the calculation of the environmental factors for the RPV inlet and outlet nozzles and the feedwater nozzle. Explain how each parameter used in the calculation was determined.

Response: The environmental fatigue calculations for the recirculation inlet and outlet nozzles and the feedwater nozzle are contained in Structural Integrity Associates Calculation No. OC-05Q-314, Revision 0, "Environmental Fatigue Calculations for RPV Locations" (proprietary).

The calculations for all three of these locations are performed in accordance with NUREG/CR-6583 (ANL-97/18), "Effects of LWR Coolant Environments on Fatigue Design Curves of Carbon and Low-Alloy Steels," March 1998, as the limiting locations for all three components are low alloy steel material.

All three locations were evaluated in a similar fashion, based on the governing fatigue calculation for each component, with the following specifics:

Recirculation Inlet Nozzle: Bounding Fen multipliers for hydrogen water chemistry (HWC) and normal water chemistry (NWC) were determined based on maximum transient temperature, minimum (saturated) assumed strain rate, and oxygen values estimated for the recirculation system. An overall usage factor was computed considering the NWC Fen value for the time period prior to HWC implementation (41%) and the HWC Fen value for the time period after HWC implementation until the end of the 60-year operating period (59%).Recirculation Outlet Nozzle: The fatigue usage at the outlet nozzle is greater than at the inlet nozzle, primarily because the outlet nozzle experiences the added thermal transients associated with operation of the Isolation Condenser.

As a result, the fatigue usage for the outlet nozzle was calculated using a more detailed approach.

Load pair specific Fen multipliers for hydrogen water chemistry (HWC) and normal water chemistry (NWC) were determined based on the maximum load pair temperature, average computed (tensile) strain rate, and oxygen values estimated for the recirculation system. Because load-pair specific Fen multipliers were determined based on load-pair specific strain rates and temperatures, the overall Fen multiplier for the recirculation outlet nozzle was determined to be significantly lower than the bounding value described above for the recirculation inlet nozzle. An overall usage factor was computed considering the NWC Fen value for the time period prior to HWC implementation (41%) and the HWC Fen value for the time period after HWC implementation until the end of the 60-year operating period (59%).Feedwater Nozzle: A revised CUF of 0.389 was computed for the feedwater nozzle for 60 years of projected cycles. Similar to the recirculation outlet nozzle, load-pair-specific Fen multipliers for hydrogen water chemistry (HWC) and normal water chemistry (NWC) were determined based on the maximum load pair temperature, average computed (tensile) strain rate, and oxygen values estimated for the feedwater system. These Fe. multipliers were determined to be 2.45 for each condition in accordance with NUREG/CR-6583 requirements.

An overall usage factor of 0.955 was computed for 60 years of projected cycles (= 2.45 x 0.389). This considered the NWC Fen value for the time period prior to HWC June 12, 2006 Supplement Page 2 of 4 implementation (41%) and the HWC Fen value for the time period after HWC implementation until the end of the 60-year operating period (59%).The feedwater nozzle was repaired 7 years after plant startup, when the cladding inside the nozzle was removed and replacement thermal sleeves and spargers were installed.

Therefore, the evaluation period for the environmental fatigue analysis was adjusted to 53 years. Based on this, the 53-year usage factor, including environmental effects, was calculated as (53/60) x 0.955 = 0.843. The overall Fen multiplier for the feedwater nozzle is therefore shown in the LRA as 0.843 10.389 = 2.17.As a result of a recent review of our documents, it was noticed that some of the fatigue usage factors cited in Section 4.3 of the OC LRA do not correspond to the values in our latest fatigue calculations.

Some fatigue values changed slightly as a result of incorporation of comments during the finalization of these calculations.

As part of the corrective actions for this finding a complete review of all of the values cited in LRA Section 4 was performed to ensure the fidelity of the information provided.

The changes are shown in bold face on the new Table 4.3.4-1 (below). The changes are relatively small and do not impact the conclusions discussed in the application.

June 12, 2006 Supplement Page 3 of 4 Table 4.3.4-1 Environmental Fatigue Results for Oyster Creek for NUREGICR-6260 Components 60-Year 60-Year Fatigue Overall Fatigue Usage Factor Environmental NUREG/CR-6260 Equivalent OCGS Material Usage Factor with Fatigue Location Location (1) Environmental Multiplier Effects (2)Reactor Vessel (Lower Reactor Vessel (Vessel- Low Alloy Steel 0.0004 0.0042 10.28 Head to Shell Head Junction)Transition)

Feedwater Nozzle Feedwater Nozzle Low Alloy Steel 0.3889 0.8433 2.17 Recirculation System Isolation Condenser Return (RHR Return Line Tee and the RPV inlet and Line Tee into SDC Line Stainless Steel 0.54- .495 outlet nozzles) 0.1205 0.43 3.57 RPV inlet nozzle Low Alloy Steel 0.0151 0.1554 10.28 RPV outlet nozzle Low Alloy Steel 0111 0.978 5.34.1832 Core Spray System Core Spray Nozzle Low Alloy Steel 0.0013 0.0129 10.28 (Nozzle and Safe End) Core Spray Nozzle Safe End Stainless Steel 0.0006 0.0072 12.48 Residual Heat Bounded by Isolation Stainless Steel N/A N/A N/A Removal Line Condenser Return Line Tee (Tapered Transition)

Location Above Feedwater Line Limiting Class 1 Location in Carbon Steel 0 @1782-(Feedwater/RCIC Tee the Feedwater Line 0.0245 0.0767 3.13 Connection)

Notes: I. Revised fatigue usage factors were computed for all of the NUREG/CR-6260 components based on projected cycles for 60 years of plant operation and updated ASME Code fatigue methodology.

2. Environmental fatigue usage was computed using the methodology of NUREG/CR-6583 (for carbon/low alloy steels) and NUREG/CR-5704 (for stainless steels), as appropriate for the material for each location.June 12, 2006 Supplement Page 4 of 4