NLS2009089, Response to Request for Additional Information for the Review of License Renewal Application

Response to Request for Additional Information for the Review of License Renewal Application

ML093130069
Person / Time
Site:	Cooper
Issue date:	11/04/2009
From:	Minahan S Nebraska Public Power District (NPPD)
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
NLS2009089
Download: ML093130069 (15)

Text

Nebraska Public Power District "Always there when you need us" 54.17 NLS2009089 November 4, 2009 U.S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, D.C. 20555-0001

Subject:

Response to Request for Additional Information for the Review of Cooper Nuclear Station License Renewal Application Cooper Nuclear Station, Docket No. 50-298, DPR-46

References:

1. Letter from Tam Tran, U.S. Nuclear Regulatory Commission, to Stewart B. Minahan, Nebraska Public Power District, dated October 7, 2009, "Request for Additional Information for the Review of the Cooper Nuclear Station License Renewal Application (TAC No. MD9763 and MD9737)."

2. Letter from Stewart B. Minahan, Nebraska Public Power District, to U.S.

Nuclear Regulatory Commission, dated September 24, 2008, "License Renewal Application" (NLS2008071).

3. Letter from Stewart B. Minahan, Nebraska Public Power District, to U.S.

Nuclear Regulatory Commission, dated June 15, 2009, "Response to Request for Additional Information for License Renewal Application

- Aging Management Programs" (NLS2009040).

Dear Sir or Madam:

The purpose of this letter is for the Nebraska Public Power District (NPPD) to respond to the Nuclear Regulatory Commission Request for Additional Information (RAI) (Reference 1) regarding the Cooper Nuclear Station License Renewal Application (Reference 2). This response is provided in Attachment 1. Additionally, in a telephone conference call conducted on September 17, 2009, NPPD agreed to provide a supplement to RAI 3.0.1, which was initially responded to in Reference 3. This supplement is provided in Attachment 2.

Should you have any questions regarding this submittal, please contact David Bremer, License Renewal Project Manager, at (402) 825-5673.

COOPER NUCLEAR STATION P O. Box 98 / Brownville, NE 68321-0098 Telephone: (402) 825-3811 / Fax: (402)825-5211 3

www~nppd.com j 1

NLS2009089 Page 2 of 2 I declare under penalty of perjury that the foregoing is true and correct.

Executed on _/IL/__

(Date)

Sincerely, OtewatB Miahan Vice President - Nuclear and Chief Nuclear Officer

/wv Attachments cc: Regional Administrator w/ attachments USNRC - Region IV Cooper Project Manager w/ attachments USNRC - NRR Project Directorate IV-1 Senior Resident Inspector w/ attachments USNRC - CNS Nebraska Health and Human Services w/ attachments Department of Regulation and Licensure NPG Distribution w/ attachments CNS Records w/ attachments

NLS2009089 Attachment 1 Page 1 of 5 Attachment 1 Response to Request for Additional Information for License Renewal Application Cooper Nuclear Station, Docket No. 50-298, DPR-46 The Nuclear Regulatory Commission (NRC) Request for Additional Information (RAI) regarding the License Renewal Application is shown in italics. The Nebraska Public Power District's (NPPD) response to this RAI is shown in block font.

NRC Request: RAIB.I.18-5

Background

In a letter datedJune 15, 2009, Cooper NuclearStation (CNS) responded to requestfor additionalinformation (RAI) B.]. 18-4, regardingthe classificationof the CHECWORKS software, which is used in the flow-acceleratedcorrosionprogram. CNS stated that CHECWORKS is classifiedas Level C, "Business Important,"based on being used "to provide information to plant managementfor decision-makingactivities which do not affect the immediate ability to operate the plantyet could threaten long term operability." Asjustification for not classifying it as Level B "LicensingBasis, "the response stated that "CHECWORKS is not used to verify continued compliance with regulatoryrequirements or commitments." According to CNS, its previous commitment, made in response to NRC Bulletin 8 7-01, regardinguse of improvedpredictive models, was a "one-time commitment to augment the [flow-accelerated corrosion]program,"which had been implemented.

In reviewing the RAI response, the staff identified several clarificationneeded items which are listed below.

Issue By letter datedSeptember 1, 1987, CNS respondedto NRC Bulletin 87-01, "Thinning of Pipe Walls in Nuclear Power Plants." The response indicatedthat the existing program would be enhanced "to provide a systematic approachto the existing inspection, data collection, evaluation, andrecord retention methods." In addition, the response noted that the program to monitor pipe wall thinningwould be augmented to include the use of improvedpredictive models in the selection ofpipe inspection points, with scheduled implementation of these program improvements to be completed before the refueling outage in February1988.

To support license renewal application(LRA) for extended operation, the applicantcredits the enhancement of the program to monitor pipe wall thinning to be consistent with the generic aging lessons learned (GALL) reportaging managementprogram (AMP) recommendation. The

NLS2009089 Attachment 1 Page 2 of 5 enhancement consists of the use of improvedpredictive models in the selection ofpipe inspection points, with scheduled implementation of these program improvements. The staff understands that, although initialimplementation of "improvedpredictive models" is a one-time action, the use of the improvedpredictive models is not a "one-time commitment, "but rathera needed ongoing commitment for the program during the period of extended operation in order to maintainconsistency with the GALL reportAMP recommendation. This ongoing commitment includes Software QA associatedwith the use of computer codes for predictive modeling (e.g.,

CHECWORKS).

The ongoing nature of the use ofpredictive software appearsto be reinforced in CNS' letter datedJuly 13, 1989, in response to Generic Letter (GL) 89-08, "Erosion/Corrosion- Induced Pipe Wall Thinning." The response stated that "along term erosion/corrosionprogram has been put in place at Cooper,"that "usesprocedures andadministrativecontrols which are equivalent to those describedin the NUMARC program." The NUMARC programdescribedpersonal-computer based software that 1) ranked components in piping systems in order of susceptibility,

2) chose the most susceptible locationsfor inspections, and 3) used inspection data to develop a plant-specific model to predict the time to reach minimum requiredwall thickness.

In addition, the informationprovided in the LRA, for the UpdatedSafety Analysis Report Supplement, Section A.]. 1.118, "Flow-AcceleratedCorrosionProgram," indicates that this is an existingprogram, which is based on EPRIs recommendations in NSAC-202L report, that predicts, detects, and monitorsflow-acceleratedcorrosion at CNS. NSAC-202L report recommends that a detailedflow-acceleratedcorrosionanalysis be performedusing a predictive methodology such as CHECWORKS, but also notes that any analyticaltool that covers the necessaryplant design, operating,and water chemistry conditions may be selected Based on information obtainedby the NRC staff during the regulatory audit of 4/20 - 4/24/09, CNS is currently using the CHECWORKS software as the analytical toolfor the predictive methodology.

Hence, based on the combined information in its responses to Bulletin 87-01, and GL-89-08, and LRA Section A.]. 1.118, CNS has an ongoing commitment to have aflow-acceleratedcorrosion program based on enhancement of the program to use CHECWORKS. The capability to analyticallypredictsusceptible locations (e.g., CHECWORKS) is a necessary attributeof such a program that is discussedwithin referenced documents.

Although there is no requirementas to how this capability should be implemented, CNS chose to use the CHECWORKS software as the means to predict,detect, and monitor wall thinning in its flow-accelerated corrosionprogram.

Request Since the CHECWORKS software is not classified as Level B, "LicensingBasis, "as justified in the response to RAI B. 1.18-4, the staff requests a descriptionof how the flow-accelerated

NLS2009089 Page 3 of 5 corrosionAMP will meet all applicable licensing basis requirementsduring the period of extended operation,specifically with respect to.

-using improvedpredictive models (e.g., CHECWORKS)

-being equivalent to the NUMARC program,and

-being based on EPRI recommendations in NSA C-202L.

NPPD Response:

As stated in LRA Section B. 1.18, the Flow-Accelerated Corrosion (FAC) program at CNS is consistent with the program described in NUREG-1801,Section XI.M17, "Flow-Accelerated Corrosion." Consistency with NUREG-1801 XI.M17, which invokes the program description in NSAC-202L, means that the CNS program is essentially the same program described in NSAC-202L which includes the use of a predictive model, such as CHECWORKS, to assist in the selection of critical inspection locations. The EPRI-NSAC program meets the NUMARC guidance which was cited in the CNS response to GL 89-08. Whether the software is classified as Level B or Level C is unrelated to meeting the licensing basis requirements during the period of extended operation as the referenced guidance documents do not specify a particular level for software classification.

The following clarification is provided regarding the discussion in the Issue section of this RAI.

It should be noted that the use of CHECWORKS is not characterized as a regulatory commitment for future action proposed in the LRA, since the established FAC Program already includes the use of CHECWORKS as the analytical tool for predictive modeling.

The use of predictive software in the CNS FAC Program is described in the LRA Section B. 1.18 discussion of consistency with NUREG-1801,Section XI.M17. CHECWORKS is the predictive software used in the CNS FAC Program. The CHECWORKS software is maintained under the CNS Software Quality Assurance Program which is based on ANSI/IEEE Standard 730 - 1989 "Standard for Software Quality Assurance Plans" and NUREG/CR-4640 "Handbook of Software Quality Assurance Techniques Applicable to the Nuclear Industry." In accordance with these standards, this software is classified as Software Quality Assurance (SQA) Level C which provides requirements for procurement, testing, and documentation. A software change request process provides controls to ensure proper change management, and is used for the review of proposed CHECWORKS software revisions and updates obtained through participation in the CHECWORKS Users Group.

While the classification procedure states that Level B software products are important to compliance with regulatory requirements/commitments, the detailed classification criteria indicate that this classification applies to software used in certain operating plant structures, systems, and components and to software used as the primary means to verify compliance with

NLS2009089 Page 4 of 5 the Technical Specifications or regulatory requirements/commitments. The use of CHECWORKS satisfies the criterion for predictive modeling in the FAC Program, but the CHECWORKS software is not used to verify compliance with regulatory commitments. The CHECWORKS software classification as SQA Level C was reviewed and confirmed by NPPD following the NRC regional license renewal inspection via the Corrective Action Program. This classification level is consistent with other nuclear power plants using similar software under similar software quality assurance programs.

In summary, the FAC Program at CNS, based on EPRI recommendations in NSAC-202L as described above, will ensure that the effects of aging are managed such that the intended functions of affected components will be maintained throughout the period of extended operation.

NRC Request: B. 1.18-6

Background

CNS LRA, Section B. 1.18, as modified by CNS letter datedJune 15, 2009, states:

The Flow-Accelerated Corrosion (FAG) Program is an existing program that applies to safety-related and nonsafety-relatedcarbon steel components and gray cast iron in systems containinghigh energy fluids carryingtwo-phase or single-phase high-energy fluid per the criteriagiven in EPRINSA C-202L. [emphasis added by NRC]

Issue GALL Section XI.M17, "Flow-AcceleratedCorrosion,"and NSA C-202L, "Recommendationsfor an Effective Flow-Accelerated CorrosionProgram,"discuss steel, carbon steel, and low alloy steel components as those covered within the scope of the programsdescribedtherein. However, neither document contains a discussion with regardto aflow-acceleratedcorrosionprogram being applicable to managing loss of materialfor gray cast iron components. Note that NSAC-202L report recommends a detailedflow-acceleratedcorrosionanalysis be performed using a predictive methodology such as CHECWORKS, but also notes that any analytical tool that covers the necessaryplant design, operating,and water chemistry conditions may be selected Based on information obtainedby the NRC staff during the regulatory audit of 4/20 - 4/24/2009, CNS is currently using the CHECWORKS software as the analytical toolfor the predictive methodology in its flow-acceleratedcorrosionprogram.

Request (1) Explain how the CNS flow-acceleratedcorrosionprogramwill effectively manage the relevant aging effects for gray cast iron.

NLS2009089 Page 5 of 5 (2) Provide information, including relevant operatingexperience, regardingthe ability of the CHECWORKS software to reasonablypredictflow acceleratedcorrosionfor gray cast iron components.

NPPD Response:

As stated in LRA Section B. 1.18, the FAC Program at CNS is based on EPRI recommendations in NSAC-202L and is consistent with the program described in NUREG-1801,Section XI.M17, "Flow-Accelerated Corrosion." NUREG-1 801 XI.M1 7 further clarifies the program description to include the performance of an analysis to determine critical locations, limited baseline inspections to determine the extent of thinning at these locations, follow-up inspections to confirm the predictions, and repairing or replacing components as necessary.

(1) The FAC Program manages the aging effect of loss of material for gray cast iron steam traps and valve bodies as listed in LRA Table 3.3.2-14-2 "Auxiliary Steam System -

Nonsafety-Related Components Affecting Safety-Related Systems." Based on system operating experience, operating characteristics, and pipe size, the auxiliary steam system is included in the FAC Program as "susceptible non-modeled (SNM)." Thus, the predictive analysis software is not used for predicting FAC wear rates in this system. The effects of aging on steam traps and valve bodies are managed in the same manner regardless of their material of fabrication through visual inspections as described in the "scope of program" element in NUREG-1801 XI.M17. Inspection locations for SNM piping and components are selected based on relative FAC susceptibility and can include components such as steam traps and valve bodies. Considerations for inspections of SNM piping and components are the same as for modeled piping and include high wear locations, components known within the industry to be particularly susceptible, and complex geometry configurations.

(2) As discussed above, the auxiliary steam system is included in the FAC Program as "susceptible non-modeled (SNM)," thus the CHECWORKS modeling software is not used to predict flow-accelerated corrosion for steam traps and valve bodies, regardless of the material of fabrication. Aging effects on these components are managed using inspections as discussed above. Flow accelerated corrosion has not been identified in gray cast iron components at CNS.

The FAC Program at CNS, based on EPRI recommendations in NSAC-202L, will ensure that the effects of aging are managed such that the intended functions of affected components will be maintained throughout the period of extended operation.

NLS2009089 Page 1 of 7 Attachment 2 Response to Miscellaneous Topics Regarding the License Renewal Application Cooper Nuclear Station, Docket No. 50-298, DPR-46 Dialogue has occurred with the Nuclear Regulatory Commission (NRC) staff based on previous responses to Requests for Additional Information (RAI). As documented in the summary of the telephone conference call conducted on September 17, 2009, the Nebraska Public Power District (NPPD) agreed to provide supplemental information to the response to RAI 3.0.1. The NRC supplemental RAI is shown in italics. The NPPD supplemental response to this RAI is shown in block font.

NRC Supplemental Request: RAI 3.0.1 In response to RAI 3. 0. 1, the applicantindicatedthat the new Aging Management Programs (AMPs) in the Cooper Nuclear Station (CNS) license renewal applicationare designedto be consistent with the Generic Aging Lessons Learned Report, which is in turn, based on a wide range of industry experience. With regardto provide applicableoperatingexperience (OE) to demonstrateprogram effectiveness of new AMPs, the applicantstated that such a commitment was unnecessary as there was ample opportunityfor Region IV oversight through the normal inspectionprocess.

The staff clarifiedthat the intent of this RAI was to obtain CNS-specific information that relates to how these new AMPs will be implemented, which is neededfor the safety evaluation report (SER) review. The staff requested clarificationon CNS-specific operatingexperience relevant to the new AMPs that would provide objective evidence that these programs,as envisioned, would be effective.

The applicantprovided the following clarifications:

To facilitate the staff's review, the applicantwill provide a supplement to the RAI 3.0. 1 response that describes examples of relevant OEfor each new AMP, with the understandingthat in some cases there are no examples of the associatedaging effects at CNS and no operatingexperience at CNS indicatingthe needfor an aging managementprogram.

NPPD Supplemental Response:

The following data is provided as clarifying information for the original response to RAI 3.0.1 (NPPD letter NLS2009040 dated June 15, 2009, ADAMS Accession Number ML091690050).

NLS2009089 Page 2 of 7 (1) Aboveground Steel Tanks (B.1.1)

The components in the scope of this new program are the fire water storage tanks. As stated in the response to RAI B. 1.1.1 (NPPD letter NLS2009040 dated June 15, 2009),

NPPD has identified no site-specific operating experience that would provide an indication that loss of material is occurring on the bottom surfaces of these tanks. The internal surface of the tank walls is managed by the Fire Water System Program, as described in License Renewal Application (LRA) Section B. 1.17, through visual inspections. The most recent internal inspections of the tanks in September 2007 found no signs of corrosion of the internal surface of the tank walls or of the tank bottoms. The most recent visual inspections of the external surface of the tanks in September 2009 found minor general corrosion tightly adhered to the tank surface with no rust blooms.

The review of operating experience at CNS concluded that no age-related failures of these tanks have occurred at CNS, and no aging mechanisms not considered in NUREG-1801 have been identified. The visual inspection and thickness measurement methods used in this program to detect aging effects are proven industry techniques that have been effectively used at CNS in other programs. Accordingly, there is reasonable assurance that this new aging management program will be effective during the period of extended operation.

(2) Buried Piping and Tanks Inspection (B. 1.3)

An assessment of underground diesel generator fuel oil tank piping at CNS was completed in 2006. The method used was ultrasonic inspection. Analysis of the results indicated no loss of intended function due to loss of material would occur prior to 2043, which is nine years beyond the end of the period of extended operation. No aging mechanisms that had not previously been considered in NUREG-1801 were identified.

A water leak in the underground fire water system at CNS was noted in December 2008.

Two cracks were identified through visual inspection in a fire water system valve body.

The outside surface was coated and there was no evidence of pitting or coating degradation. There was no evidence of wall thinning, and only minor surface corrosion was found. An evaluation determined that an external overstress condition not related to aging had been imposed on the valve during maintenance in the area earlier in the year, which led to the cracking of the valve body. Since this was an event-driven condition not caused by the effects of aging, the condition did not warrant changes to the new Buried Piping and Tanks Inspection Program that was to be described in LRA Section B. 1.3.

The Buried Piping and Tanks Inspection Program will be consistent with the program described in NUREG-1801, Volume 2, Revision 1,Section XI.M34, Buried Piping and Tanks Inspection. As stated in Section XI.M34, industry operating experience shows that this program is effective in managing corrosion of external surfaces of buried steel piping

NLS2009089 Page 3 of 7 and tanks through the use of visual inspections. Accordingly, there is reasonable assurance that this new aging management program will be effective during the period of extended operation.

(3) Metal-Enclosed Bus Inspection Program (B. 1.22)

As stated in NUREG 1801 Volume 2, Revision 1,Section XI.E4, industry operating experience includes failures on metal enclosed buses (MEBs) caused by cracked insulation (insulators) and moisture or debris buildup internal to the MEB. Operating experience has also shown that bus connections in the MEBs exposed to appreciable ohmic heating during operation may experience loosening due to repeated cycling of connected loads. However, no age-related failures of MEBs due to aging effects managed by this program have been found at CNS, and no aging mechanisms not previously considered in NUREG-1801 have been identified. Visual inspections of busses in 2009 revealed degraded bus bar protection boots, partially detached bus bar supports, partially exposed bus connections, and a broken support strap on a bus cover.

These conditions did not result in a loss of intended function, and repairs were scheduled and completed in accordance with the work management process. The methods used in this program to detect aging effects are proven industry techniques that have been effectively used at CNS in other programs. Accordingly, there is reasonable assurance that this new aging management program will be effective during the period of extended operation.

(4) Non-EQ Bolted Cable Connections (B. 1.24)

This program applies to a potential aging effect (loosening of non-EQ bolted cable connections - increased connection resistance) for which there is currently no industry or site-specific operating experience indicating the need for an aging management program.

The guidance from the proposed LR-ISG-2007-02 was considered in the development of this program. The elements of the program inspections (e.g., the scope of the inspections and inspection techniques) are consistent with industry practice and have been used effectively at CNS in other programs. Accordingly, there is reasonable assurance that this new aging management program will be effective during the period of extended operation.

(5) Non-EQ Inaccessible Medium Voltage Cable (B. 1.25)

As stated in NUREG 1801 Volume 2, Revision 1,Section XI.E3, industry operating experience has shown that cross linked polyethylene (XLPE) or high molecular weight polyethylene insulation materials are most susceptible to water tree formation. The formation and growth of water trees varies directly with operating voltage. Minimizing exposure to moisture minimizes the potential for the development of water treeing. Other

NLS2009089 Page 4 of 7 insulation materials (such as ethylene propylene rubber (EPR)) are less susceptible to water treeing than XLPE. The medium-voltage cables included in this program at CNS have EPR insulation material. However, no age-related failures of medium voltage cables and connections have been found at CNS, and no aging mechanisms not considered in NUREG-1801 have been identified.

As stated in LRA Section B. 1.25, the Non-EQ Inaccessible Medium-Voltage Cable Program entails periodic inspections for water collection in cable manholes and periodic testing of cables. A search of CNS operating experience with manholes containing in-scope medium-voltage cables identified one event. The event, which occurred in 2003, was for a high-level alarm in the control room due to failure of a manhole sump pump to auto-start. Due to the automatic sump pumps and associated high-level alarms in the manholes, an inspection frequency of at least once every two years for manhole inspections is adequate for the Non-EQ Inaccessible Medium-Voltage Cable Program.

RAI B. 1.25-1 and the NPPD response (NPPD letter NLS2009040 dated June 15, 2009) concern water in electrical manholes identified in April 2009. Evaluation of the condition determined that the affected manholes did not house cables that performed a license renewal intended function. Consequently, the manholes need not be included in the Non-EQ Inaccessible Medium-Voltage Cable Program. Unlike these manholes, electrical manholes that are included in the program are provided with sump pumps to ensure that unacceptable levels of water are not present. Therefore, this operating experience does not indicate the need to modify the Non-EQ Inaccessible Medium-Voltage Cable Program provisions for monitoring water level in manholes. The program as described provides reasonable assurance that this new aging management program will be effective during the period of extended operation.

(6) Non-EQ Circuits Test Review (B. 1.26)

As stated in NUREG 1801 Volume 2, Revision 1,Section XI.E2, industry operating experience has identified a case where a change in temperature across a high range radiation monitor cable in containment resulted in substantial change in the reading of the monitor. Changes in instrument calibration can be caused by degradation of the circuit cable and are a possible indication of electrical cable degradation. The vast majority of industry operating experience regarding neutron flux instrumentation circuits is related to cable/connector issues inside containment near the reactor vessel. However, no age-related failures of neutron monitoring and high range radiation monitoring system cables and connections have been found at CNS, and no aging mechanisms not considered in NUREG-1801 have been identified. Accordingly, there is reasonable assurance that this new aging management program will be effective during the period of extended operation.

NLS2009089 Page 5 of 7 (7) Non-EQ Insulated Cables and Connections (B. 1.27)

As stated in NUREG 1801 Volume 2, Revision 1,Section XI.E 1, industry operating experience has shown that adverse localized environments caused by heat or radiation for electrical cables and connections may exist near steam generators, pressurizers or hot process pipes, such as feedwater lines. In this industry experience, such adverse localized environments have caused degradation of insulating materials on electrical cables and connecdions that is visually observable, such as color changes or surface cracking. These visual indications can indicate cable degradation. The examination techniques used in this program to detect aging effects are proven industry techniques that have been effectively used at CNS in other programs. However, no age-related failures of cables or cable connections with a license renewal intended function have been found at CNS, and no aging mechanisms not considered in NUREG- 1801 have been identified.

Accordingly, there is reasonable assurance that this new aging management program will be effective during the period of extended operation.

(8) One-Time Inspection (B. 1.29)

This inspection program applies to potential aging effects for which there is currently no operating experience at CNS indicating the need for an aging management program. As stated in NUREG 1801 Volume 2, Revision 1,Section XI.M32, the elements of these inspections (e.g., the scope of the inspections and inspection techniques) are consistent with industry practice. They have also proven effective at CNS for detection of aging effects outside of this program. Accordingly, there is reasonable assurance that this new aging management program will be effective during the period of extended operation.

(9) One-Time Inspection - Small Bore Piping (B. 1.30)

This inspection program applies to a potential aging effect (cracking of ASME Code Class 1 piping less than 4 inches nominal pipe size) for which there is no operating experience at CNS that indicates the need for an aging management program.

Examinations of small bore piping were performed during the third inservice inspection interval (2002). These inspections used demonstrated inspection techniques (ultrasonic examination) in accordance with ASME Code requirements. These inspections detected no indications of cracking at any of the examined locations.

As stated in NUREG 1801 Volume 2, Revision 1,Section XI.M35, this program uses volumetric inspection techniques with demonstrated capability and a proven industry record to detect cracking in piping weld and base material. These techniques are being effectively used at CNS as shown by the operating experience presented above.

Volumetric examinations will continue to be performed by qualified personnel following

NLS2009089 Page 6 of 7 procedures that are consistent with ASME Section XI and 10 CFR 50, Appendix B.

Accordingly, there is reasonable assurance that this new aging management program will be effective during the period of extended operation.

(10) Selective Leaching (B.1.34)

As stated in the response to RAI B. 1.34-1 (NPPD letter NLS2009040 dated June 15, 2009), the review of operating experience at CNS identified no occurrence of selective leaching. As stated in NUREG 1801 Volume 2, Revision 1,Section XI.M33, the inspection elements of this program (e.g., the scope of the inspections and inspection techniques) are consistent with industry practice and will be effective in managing the aging effect included in this program. Accordingly, there is reasonable assurance that this new aging management program will be effective during the period of extended operation.

(11) Thermal Aging and Neutron Irradiation Embrittlement of Cast Austenitic Stainless Steel (CASS) (B.1.37)

This program applies to potential aging effects (thermal aging and neutron irradiation embrittlement) for which there is no operating experience at CNS indicating the need for an aging management program. As stated in NUREG 1801 Volume 2, Revision 1,Section XI.M13, this new program was developed using research data (NUREG/CR-4513, Revision 1) obtained on both laboratory-aged and service-aged materials. The proposed inspection techniques specified by the program for examination of flaws are proven techniques used to satisfy ASME Code inspection requirements.

As previously stated in the original response to this RAI with regard to future operating experience, an operating experience review program exists at CNS under the current licensing basis. This program monitors industry-wide operating experience from a number of sources (e.g., INPO reports and NRC Information Notices). Each item is reviewed for applicability to CNS. Applicable items are assigned to a responsible individual as a corrective action under the CNS corrective action program. This process assures proper evaluation of operating experience.

In addition, LRA Section B.0.3 indicates that each new aging management program includes program elements for corrective actions and confirmation process that are consistent with the recommendations ofNUREG-1801. These program elements entail actions to preclude recurrence of deficiencies in CNS aging management programs that may be revealed through operating experience (both plant-specific and industry-wide). These program elements apply on an ongoing basis, providing a feedback mechanism based on operating experience that ensures continuing program effectiveness throughout the period of extended operation. The corrective action process is an established process subject to ongoing routine oversight by full-time NRC inspectors at the plant site. This ongoing process assures the effectiveness of the development

NLS2009089 Page 7 of 7 and maintenance of the new CNS programs without the need for a commitment to provide future operating experience.

ATTACHMENT 3 LIST OF REGULATORY COMMITMENTS© 4 4

ATTACHMENT 3 LIST OF REGULATORY COMMITMENTSO Correspondence Number: NLS2009089 The following table identifies those actions committed to by Nebraska Public Power District (NPPD) in this document. Any other actions discussed in the submittal represent intended or planned actions by NPPD. They are described for information only and are not regulatory commitments. Please notify the Licensing Manager at Cooper Nuclear Station of any questions regarding this document or any associated regulatory commitments.

COMMITMENT COMMITTED DATE COMMITMENT NUMBER OR OUTAGE None 1~ 1~

.1.

~1* 4

+ +

4 4 PROCEDURE 0.42 REVISION 24 PAGE 19 OF 26