ML083440059

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License Amendment Request Pursuant to 10 CFR 50.90: One-Time Extension of the Primary Containment Integrated Leakage Rate Test Interval - Response to NRC Request for Additional Information
ML083440059
Person / Time
Site: Nine Mile Point Constellation icon.png
Issue date: 12/04/2008
From: Polson K
Constellation Energy Group, Nine Mile Point
To:
Document Control Desk, Office of Nuclear Reactor Regulation
References
TAC MD9453
Download: ML083440059 (34)
v • d • e


Text

Keith J. Poison P.O. Box 63 Vice President-Nine Mile Point Lycoming, New York 13093 315.349.5200 315.349.1321 Fax Constellation Energy-Nine Mile Point Nuclear Station December 4, 2008 U. S. Nuclear Regulatory Commission Washington, DC 20555-0001 ATTENTION: Document Control Desk

SUBJECT:

Nine Mile Point Nuclear Station Unit No. 1; Docket No. 50-220 License Amendment Request Pursuant to 10 CFR 50.90: One-Time Extension of the Primary Containment Integrated Leakage Rate Test Interval - Response to NRC Request for Additional Information (TAC No. MD9453)

REFERENCES:

(a) Letter from K. J. Polson (NMPNS) to Document Control Desk (NRC), dated August 15, 2008, License Amendment Request Pursuant to 10 CFR 50.90: One-Time Extension of the Primary Containment Integrated Leakage Rate Test Interval - Technical Specification Section 6.5.7, 10 CFR 50 Appendix J Testing Program Plan (b) Letter from R. V. Guzman (NRC) to K. J. Poison (NMPNS), dated November 6, 2008, Request for Additional Information Regarding Nine Mile Point Nuclear Station, Unit No. 1, One-Time Extension of the Primary Containment Integrated Leakage Rate Test Interval (TAC No. MD9453)

Nine Mile Point Nuclear Station, LLC (NMPNS) hereby transmits supplemental information requested by the NRC in support of a previously submitted request for amendment to Nine Mile Point Unit 1 (NMP1)

Renewed Operating License DPR-63. The initial request, dated August 15, 2008 (Reference a) proposed to revise Technical Specification Section 6.5.7, "10 CFR 50 Appendix J Testing Program Plan," to allow a one-time extension of the Integrated Leakage Rate Test (ILRT) interval for no more than five (5) years.

The supplemental information, provided in Attachment 1 to this letter and Attachments 2 and 3 referenced therein, responds to the request for additional information (RAI) documented in the NRC's letter dated November 6, 2008 (Reference b).

This supplemental information does not affect the No Significant Hazards Determination analysis provided by NMPNS in Reference (a). Pursuant to 10 CFR 50.91(b)(1), NMPNS has provided a copy of this supplemental information to the appropriate state representative. This letter contains ho new regulatory commitments.

/1D/7

Document Control Desk December 4, 2008 Page 2 Should you have any questions regarding the information in this submittal, please contact T. F. Syrell, Licensing Director, at (315) 349-5219.

Very truly yours, STATE OF NEW YORK

TO WIT:

COUNTY OF OSWEGO I, Keith J. Poison, being duly sworn, state that I am Vice President Nine Mile Point, and that I am duly authorized to execute and file this supplemental information on behalf of Nine Mile Point Nuclear Station, LLC. To the best of my knowledge and belief, the statements contained in this document are true and correct. To the extent that these statements are not based on my personal knowledge, they are based upon information provided by other Nine Mile Point employees and/or consultants. Such information has been reviewed in accordance with company practice and I believe it to be reliable.

Subscribed and sworn before me, a Notary Public in and for the State of New York and County of I this fi- day of A 2008.

WITNESS my Hand and Notarial Seal:

Notary Public My Commission Expires:

SANDRA A. OSWALD Notary Public, State of New York Date No. 01OS6032276 Oualified In Oswego County Commission Expires _ i j$-.

KJP/DEV Attachments: 1. Nine Mile Point Unit 1 - Response to NRC Request for Additional Information Regarding the Proposed One-Time Extension of the Primary Containment Integrated Leakage Rate Test Interval

2. Review of the NMP1 PRA Model Update Peer Review Findings (RAI-5)
3. Annotated Pages from Attachment 2 to the NMPNS Submittal dated August 15, 2008 cc: S. J. Collins, NRC R. V. Guzman, NRC Resident Inspector, NRC J. P. Spath, NYSERDA

ATTACHMENT 1 NINE MILE POINT UNIT 1 RESPONSE TO NRC REQUEST FOR ADDITIONAL INFORMATION REGARDING THE PROPOSED ONE-TIME EXTENSION OF THE PRIMARY CONTAINMENT INTEGRATED LEAKAGE ]RATE TEST INTERVAL Nine Mile Point Nuclear Station, LLC December 4, 2008

ATTACHMENT 1 NINE MILE POINT UNIT 1 RESPONSE TO NRC REQUEST FOR ADDITIONAL INFORMATION REGARDING THE PROPOSED ONE-TIME EXTENSION OF THE PRIMARY CONTAINMENT INTEGRATED LEAKAGE RATE TEST INTERVAL By letter August 15, 2008, Nine Mile Point Nuclear Station, LLC (NMPNS) requested an amendment to the Nine Mile Point Unit 1 (NMPl) Renewed Facility Operating License DPR-63. The proposed change would revise Technical Specification (TS) Section 6.5.7, "10 CFR 50 Appendix J Testing Program Plan,"

to allow a one-time extension of the Integrated Leakage Rate Test (ILRT) interval for no more than five (5) years. This attachment provides supplemental information in response to the request for additional information documented in the NRC's letter dated November 6, 2008. Each individual NRC question is repeated (in italics), followed by the NMPNS response.

Containment Integrity RAI-)

Please discuss andprovide thefollowing:

a. A summary list of those containmentpenetrations (inchlding their test schedule intervals) that have not demonstrated acceptable performance history in accordance with the primary containment leakage rateprogram.
b. A summary tablefor Type B and Type C tests, inchldingthe interval schedule dates, that areplanned to be performedpriorto and during the requested 5-year extension period of the ILRT interval.
c. Type B and Type C test results and their comparison with the allowable leakage rate specified in the plant Technical Specifications.
d. Testing and schedule of those penetrations with seals and gaskets, and bolted connections that are frequently disassembledor are not routinely disassembled.

Response

a. Summary list of those containment penetrations (including their test schedule intervals) that have not demonstrated acceptable performance history in accordance with the primary containment leakage rate program.

Containment penetrations that have experienced Appendix J local leak rate test failures and their test schedule intervals are listed in Table 1, beginning with the 1999 NMP1 refueling outage (when the last ILRT was performed). A test failure represents leakage that exceeds the administrative criteria established in accordance with 10 CFR 50, Appendix J, Option B.

b. Summary table for Type B and Type C tests, including the interval schedule dates, that are planned to be performed prior to and during the requested 5-year extension period of the ILRT interval.

The planned test schedules for Type B and Type C leak rate tested components for the next three NMPI refueling outages are provided in Table 2 (Type B tests) and Table 3 (Type C tests). With approval of the 5-year ILRT interval extension request, the next ILRT would be performed during the 2013 refueling outage (N1R22). These planned test schedules were developed assuming that there are no leak rate test failures, and do not account for any leak rate tests that may be required to support maintenance activities.

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ATTACHMENT 1 NINE MILE POINT UNIT 1 RESPONSE TO NRC REQUEST FOR ADDITIONAL INFORMATION REGARDING THE PROPOSED ONE-TIME EXTENSION OF THE PRIMARY CONTAINMENT INTEGRATED LEAKAGE RATE TEST INTERVAL As indicated by Tables 2 and 3, the total number of planned Type B and Type C leak rate tests over the next three refueling outages is: 2009 (N1R20) - 82; 2011 (NIR21) - 92; and 2013 (N1R22) - 87.

c. Type B and Type C test results and their comparison with the allowable leakage rate specified in the plant Technical Specifications.

The NMP1 combined local leak rate test (Type B and Type C tests including airlocks) acceptance criterion (0.6 La) is 388.44 scfhi. The maximum and minimum pathway leak rate summary totals for the last two refueling outages are shown below.

Maximum Pathway Minimum Pathway Refueling Outage Leakage (scfh)  % of 0.6 La Leakage (scfh)  % of 0.6 La 2007 (NIR19) 240.38 61.9% 89.734 23.1%

2005 (N1R18) 222.169 57.2% 83.492 21.5%

d. Testing and schedule of those penetrations with seals and gaskets, and bolted connections that are frequently disassembled or are not routinely disassembled.

The current test schedule interval and date last tested for Type B penetrations (i.e., those with seals and gaskets, and bolted connections) are listed in Table 4 for frequently disassembled penetrations and in Table 5 for infrequently disassembled penetrations. Note that electrical and mechanical penetrations and airlocks are not included in these two tables.

RAI-2

Regulatory Position C.3 of Regulatory Guide 1.163, "Performance-Based Containment Leak-Test Program," recommends that visual examinations should be conducted prior to initiatinga Type A test, and during two other refiteling outages before the next Type A test based on a 10-year ILRT interval.

Pleasedescribe, with a schedule, how you would supplement this JO-year interval-basedvisual inspection requirementfor the requested 15-yearILRT interval.

Response

As stated in Section 3.1.2.2 of the Enclosure to the August 15, 2008, NMPNS submittal letter, the general visual examination requirements specified in the American Society of Mechanical Engineers (ASME)

Code Section XI (Subsection IWE) containment inspection program will continue to be performed during the proposed 5-year extension of the ILRT interval. In addition, visual inspections of accessible interior surfaces of the primary containment are conducted each refueling outage in accordance with approved plant procedures to provide reasonable assurance that the effects of aging will be adequately managed, as described in the NMPNS License Renewal application (Reference 1). These visual inspections include the following:

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ATTACHMENT 1 NINE MILE POINT UNIT 1 RESPONSE TO NRC REQUEST FOR ADDITIONAL INFORMATION REGARDING THE PROPOSED ONE-TIME EXTENSION OF THE PRIMARY CONTAINMENT INTEGRATED LEAKAGE RATE TEST INTERVAL Drywell and Drywell Head Interior

  • Vicinity of drywell penetrations for obvious structural discontinuities (cracks).
  • Support attachments and brackets for obvious defects (missing or broken bolts/nuts, bent rods, plate buckling, etc.).

" Internal surface area for gross signs of corrosion and deterioration (depth greater than approximately 1/16"; indications of leak).

" Internal coated surface area for any visible defects including blistering, cracking, flaking, peeling and physical or mechanical damage (area larger than approximately 6 square feet).

Suppression Chamber Interior

  • Vicinity of any penetrations for obvious structural discontinuities (cracks).
  • Vent pipe expansion joints, support structures, brackets and bolting for obvious defects (missing or broken nuts/bolts, bent rods, plate buckling, etc.).
  • Internal surface area, including water line regions, for gross signs of corrosion or buckling.

The above-described inspections are scheduled to be performed each refueling outage during the proposed 5-year extension of the ILRT interval.

RAI-3

Section 3.1.2.4 of the enclosure to your August 15, 2008, submittal, discusses IWE-1240 augmented inspection of the interior surface of the dtyvell shell. Please discuss whether there are other areas requiringaugmented examination.

Response

Other than the six localized drywell shell interior surface areas discussed in Section 3.1.2.4 of the Enclosure to the August 15, 2008, NMPNS submittal letter, there are no other areas requiring augmented examination in accordance with IWE-1240.

During the License Renewal application process, NMPNS committed to perform an augmented VT-1 visual inspection of the containment penetration stainless steel bellows using enhanced techniques qualified for detecting stress corrosion cracking (see NMP1 Updated Final Safety Analysis Report Appendix C). These inspections are beyond the scope of examinations required by Table IWE-2500-1 of the ASME Code Section XI and thus are referred to as augmented examinations in the IWIE containment inspection program plan. However, they are not considered augmented examinations as defined in IWE-1240.

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ATTACHMENT 1 NINE MILE POINT UNIT 1 RESPONSE TO NRC REQUEST FOR ADDITIONAL INFORMATION REGARDING THE PROPOSED ONE-TIME EXTENSION OF THE PRIMARY CONTAINMENT INTEGRATED LEAKAGE RATE TEST INTERVAL

RAI-4

As part of the NMP1 drywell augmented inspection/monitoringprogram,Section 3.1.2.4 of the enclosure to your submittal describes the volumetric and visual examinations of the drywell shell duringthe 2003 and 2007 refuelingoutages. Pleaseprovidefirther discussion relative to the following:

a. Generaldescription and correlationbetween the 2003 and 2007 examination results.
b. Generalcorrosion condition in the monitored areas.
c. Based on the results of 2007 examinations and anticipatedcorrosionrate,please discuss the schedule for the next ultrasonic testing measurements, root cause determination, and any planned or already implemented correctiveactions.

Response

a. General description and correlation between the 2003 and 2007 examination results.

As discussed in Section 3.1.2.4 of the Enclosure to the August 15, 2008, NMPNS submittal letter, detailed visual examinations of six localized areas of the drywell shell, coinciding with the locations of the drywell area coolers, were performed in 2003 in accordance with the ASME Section XI, Subsection IWE inspection program. These examinations identified corrosion that was characterized as "major" (i.e.,

greater than 5 percent of the base metal was judged to be lost). The code-required evaluation of this condition included taking volumetric (UT) thickness measurements to confirm that the drywell shell was acceptable for continued service (i.e., minimum wall thickness had not been violated). Due to the radiological conditions existing in the drywell during the 2003 refueling outage, the investigation of the condition was limited to four areas of the drywell shell (around 3 of the area coolers) that were considered to represent the worst areas of major corrosion. A UT thickness reading was taken at each of these four identified locations. The thickness reading locations were defined by measured distances from the floor and nearby support beams, but no grids were applied to the shell to facilitate future location of the exact spots where the thickness readings were taken. The evaluation performed in 2003 evaluated the lowest readings found at each measured location against the minimum required wall thickness and concluded that the drywell shell was acceptable for continued service.

In accordance with the drywell supplemental inspection program (submitted to the NRC by NMPNS letter dated April 4, 2006 (Reference 2) and accepted by the NRC as part of the License Renewal application review (Reference 3)), UT thickness measurements were taken during the 2007 refueling outage at the reported locations where the 2003 measurements had been taken. It was anticipated that a corrosion rate could be determined from a comparison of the 2003 and 2007 readings; however, the corrosion rates derived from that limited set of data points were widely scattered, unrealistic (one location showed a gain in wall thickness) and inconsistent with the observed condition of the drywell shell (see Item b below). It was concluded that this limited data could not be used as the sole basis for determining a corrosion rate. This result was attributed to the likelihood that the exact same spots had not been measured in 2003 and in 2007. Therefore, actions were taken during the 2007 refueling outage to establish a more repeatable means of determining wall thickness measurements so that a truly representative corrosion rate can be determined. Grids were painted on the drywell shell at the areas of interest and readings taken at multiple grid points. Measurements taken during the 2009 refueling outage 4 of 21

ATTACHMENT 1 NINE MILE POINT UNIT 1 RESPONSE TO NRC REQUEST FOR ADDITIONAL INFORMATION REGARDING TIlE PROPOSED ONE-TIME EXTENSION OF THE PRIMARY CONTAINMENT INTEGRATED LEAKAGE RATE TEST INTERVAL at the same grid points will allow actual corrosion rates to be established and addressed in accordance with the drywell supplemental inspection program acceptance criteria, which have been added to the IWE Program.

b. General corrosion condition in the monitored areas.

The areas of localized drywell shell corrosion were extensively inspected by the IME Responsible Individual during the 2007 refueling outage. These areas were observed to have a generalized corroded surface, but no evidence of loose corrosion products was present. There were no rust flakes or blisters on the surfaces, no evidence of pitting, and no build up of rust flakes on the floor below the areas. If significant shell corrosion had taken place, corrosion products should have been observed in the areas since carbon steel corrosion products expand significantly. The absence of corrosion products was inconsistent with the corrosion rates that were indicated by comparing the first 2007 set of four UT thickness measurements with the 2003 UT thickness measurement data.

c. Based on the results of 2007 examinations and anticipated corrosion rate, please discuss the schedule for the next ultrasonic testing measurements, root cause determination, and any planned or already implemented corrective actions.

In accordance with the IWE Program Plan, UT thickness measurements will be taken during the 2009 refueling outage at the grid locations established in 2007. These 2009 measurements will be compared to the baseline data established in 2007 to determine a corrosion rate for the 2-year period. The acceptance standards are tabulated in the IWE Program Plan and are the same as those given in Reference 2. The corrosion rate determined from the UT measurement data and the remaining margin to the minimum required wall thickness will determine the subsequent frequency of performing UT thickness measurements as well as the need to implement mitigative strategies (e.g., application of protective coatings, repair, or replacement of affected sections of the shell).

The apparent cause of the localized corrosion of the drywell shell in the area of each of the drywell area coolers was determined to be the cleaning practices for the area cooler coils. The procedure for cleaning the area coolers called for the coils to be rinsed with a cleaning agent. There were no protective measures for the liner and no requirement to rinse the liner after cleaning. The procedure for cleaning the cooler coils was revised in 2003 to require the use of protection on the liner before cleaning of the coolers.

Risk Analysis

RAI-5

The core damagefrequency and totalpopulation dose in the ILRT analysis (based on the 2007 PRA) are about a decade lower than in the severe accident mitigation alternative analysis (based on the 2003 PRA). Providea descriptionof the major changes to PRA models and assumptionsthat accountfor these changes. Provide a description of the peer review comments in areas related to these reductions, the resohltion of these comments, and the impact of any unresolved comments on the risk resultsfor the requested change.

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ATTACHMENT 1 NINE MILE POINT UNIT 1 RESPONSE TO NRC REQUEST FOR ADDITIONAL INFORMATION REGARDING THE PROPOSED ONE-TIME EXTENSION OF THE PRIMARY CONTAINMENT INTEGRATED LEAKAGE RATE TEST INTERVAL

Response

A full update of the NMPI probabilistic risk assessment (PRA) model in accordance with Regulatory Guide 1.200 was completed in January 2008 (referred to as the 2007 PRA model). Table 6 provides a description of the major changes to PRA models and assumptions that account for the differences between the PRA model supporting the severe accident mitigation alternatives (SAMA) analysis (the 2003 model) and the updated Regulatory Guide 1.200 compliant PRA model. The impacts are ranked relative to their impact on the internal events core damage frequency (CDF). The resulting model improvements caused a decrease in overall CDF, thus decreasing LERF.

An industry peer review team reviewed the updated PRA model in February 2008 and commended NMPNS on the quality of the NMP1 Level II analysis. Attachment 2 contains a summary of all of the findings from the peer review and addresses the impact of these findings on the NMP1 ILRT interval extension risk assessment. In summary, most of the findings are related to documentation and have no material impact on the ILRT interval extension risk assessment. Assessment of required model changes resulting from resolution of the peer review findings has determined that the changes would have a negligible, if any, impact on the conclusions of the ILRT interval extension risk assessment.

RAI-6

Explain how the population dose of 1. 05E6 person rem per event was derived for Electric Power Research Institute (EPRI) Class 7 releases (as reported in Tables 10-2 through 10-4 of Attachment 2 to the August 15, 2008, submittal). Table 6-7 indicates that the population dose for EPRI Class 7 would be a combination of releasesfrom collapsed accident progression bins (APBs) 3, 4, and 5. However, the NMPNS adjustedpopulation dose for each of these APBs (last column of Table 6-3) is well below 1E6 person rem per event. It appears that the population dose for EPRI Class 7 was calculated based on the sum of the population dose values for APBs 3, 4, and 5 rather than the frequency-weighted sum.

Reconcile the population dose values and update the risk assessment as appropriate.

Response

As discussed in Section 8 of Attachment 2 to the August 15, 2008, NMPNS submittal letter (page 26), the Class 7 population dose calculation utilized a modified EPRI 1009325, Revision 1, methodology. The EPRI guidance document uses a weighted average of values for accident progression bins 3, 4, and 5 to generate the population dose for Class 7. The methodology was simplified in the NMP1 calculation as follows: each accident progression bin frequency (bins 3, 4, and 5) was multiplied by the entire Class 7 frequency and summed, yielding a dose value that is always conservative with respect to a weighted average. Utilizing this approach is conservative and is deemed acceptable from a risk perspective.

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ATTACHMENT 1 NINE MILE POINT UNIT 1 RESPONSE TO NRC REQUEST FOR ADDITIONAL INFORMATION REGARDING THE PROPOSED ONE-TIME EXTENSION OF TIlE PRIMARY CONTAINMENT INTEGRATED LEAKAGE RATE TEST INTERVAL

RAI-7

The large early releasefrequency (LERF) is reported to be 3.OOE-7peryearfor internalevents (on page 44 ofAttachment 2) and 8.67E-7 peryearfor external events (on page B-1 of Attachment 2). This results in a total LERF of 1.1 7E-6 per year. However, on page B-3, it is stated that the total LERFfrom all hazards is 1. 7E-6 peryear. Address this inconsistency, and confirm the correct valuefor the total LERF for NMP1, with and without the requested change.

Response

Note: All of the section and page numbers referenced in the following response are referring to Attachment 2 to the August 15, 2008, NMPNS submittal letter.

As discussed in Section 6.2 (page 8), the NMP1 ILRT extension risk assessment utilized the PRA model (Level I and Level II) developed in 2007. At the time that the ILRT extension risk assessment was performed, the 2007 PRA model addressed accidents initiated by internal events at full power, and containment response to those accidents. The 2007 PRA model did not include fire and seismic event contributions. Therefore, the most recent fire and seismic models available (those that were updated in 2003) were utilized to assess the impact of external events. This bounding external events assessment is presented in Appendix B of Attachment 2.

The large early release frequency (LERF) value of 3.00E-07/year stated in Section 9.2 (page 44) is the baseline value for a 3-year ILRT interval and is from the 2007 PRA model (i.e., considers only internal events). In Appendix B, Section B.4 (page B-i), the LERF contribution from external events (fire and seismic), obtained from the 2003 PRA model, was determined to be 8.67E-07/year. Adding these two values yields a total LERF value of 1.17E-06/year. However, as also stated in Appendix B, Section B.4 (page B-3), the baseline total LERF value for all hazards (internal and external) given in the 2003 PRA is 1.7E-06/year, which is larger than the 1.1 7E-06/year value obtained by adding the 2007 PRA internal events contribution and the 2003 PRA external events contribution. Therefore, the baseline total LERF value of 1.7E-06/year from the 2003 PRA was conservatively chosen to determine the LERF increase for the proposed 5-year extension of the ILRT interval.

RAI-8

Table B-2 provides the external and internalevent contributionsto EPRI Class 3bfrequency based on the resultsfrom the 2003 PRA. Explain how the Class 3bfrequency vahte of 2.38E-9 peryearfor external events (first entry in column 2) was derived.

Response

The assessment summarized in Table B-1 of Attachment 2 to the August 15, 2008, NMPNS submittal letter is sufficient to support the conclusion of Appendix B of Attachment 2; i.e., that incorporating external event hazard risk into the analysis does not change the overall conclusion that extending the ILRT interval by 5 years is acceptable from a risk perspective.

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ATTACHMENT 1 NINE MILE POINT UNIT 1 RESPONSE TO NRC REQUEST FOR ADDITIONAL INFORMATION REGARDING THE PROPOSED ONE-TIME EXTENSION OF THE PRIMARY CONTAINMENT INTEGRATED LEAKAGE RATE TEST INTERVAL NMPNS has determined that the information in Table B-2 and the associated text discussing Table B-2 is extraneous and should therefore be disregarded. Annotated pages of Attachment 2 to the August 15, 2008, NMPNS submittal letter, showing the deletion of Table B-2 and associated text, are provided in to this letter.

A correction for Section 11 of Attachment 2 to the August 15, 2008, NMPNS submittal letter, is also provided in Attachment 2 to this letter. The value for the estimated change in LERF associated with the increase in ILRT interval from 10 years to 15 years was originally stated in Section 11 (page 58, second paragraph), as 1.911E-8/year. This value was improperly transposed from Table B-2 rather than from Table B-1. The correct value, from Table B-i, is 8.79E-08/year. The derivation of this value is as explained in Section B.4 of Attachment 2 to the August 15, 2008, NMPNS submittal letter.

References

1. Letter from J. A. Spina (NMPNS) to Document Control Desk (NRC), dated July 14, 2005, Recovery of Nine Mile Point License Renewal Application Quality (TAC Nos. MC3272 and MC3273)
2. Letter from T. J. O'Connor (NMPNS) to Document Control Desk, dated April 4, 2006, Safety Evaluation Report (SER), With Open Items Related to the License Renewal of Nine Mile Point Nuclear Station, dated March 2006 - SER Open Item 3.0.3.2.17-1 (TAC Nos. MC3272 and MC3273)
3. NUREG-1900, "Safety Evaluation Report Related to the License Renewal of Nine Mile Point Nuclear Station, Units 1 and 2," September 2006 8 of 21

ATTACHMENT 1 NINE MILE POINT UNIT 1 RESPONSE TO NRC REQUEST FOR ADDITIONAL INFORMATION REGARDING THE PROPOSED ONE-TIME EXTENSION OF THE PRIMARY CONTAINMENT INTEGRATED LEAKAGE RATE TEST INTERVAL Table 1 (RAI-la) 10 CFR 50 Appendix J Local Leak Rate Test Failures N1R15, Sp ing 1999 Refueling Outag (When Last ILRT Performed)

Penetration Comp ID System Test Test Result Test Schedule Comments (2)

Type (scfh) (1) Interval X-241 RPV Stabilizer B Containment B 17.7 (AF) 0.042 (AL) 60 to 30 months Exceeded Admin Limit, returned to 30 month interval Access Cover X-2B Test Station 6M ()Containment (3) B 39.6 (AF) 00 A)fxd 30 months blosrpae Admin Limit, MSIV bellows leak identified, Exceeded 0.061 (AL) fixed bellows replaced X-2A IV-01-03 Main Steam C 138.48 (AF) 30 months Exceeded Admin Limit, due to packing leak

_________1.07 (AL) fixed X-21 IV-01-04 Main Steam C Gross (AF) 30 months Unquantified gross leakage, MSIV internal modification 0.045 (AL) fixed implemented X-4A CKV-3 1-OIR Feedwater C 53.3 (AF) 30fix Exceeded Admin Limit, valve repaired

___________ _________ ~0.99 (AL) fixed Ecee di iivlerpie X-5A CKV-39-04 Emerg. C Gross (AF) 30 months Unquantified gross leakage, valve repaired and kept at Cooling 14.7 (AL) 30 month interval X-19 IV-201.1-09 Containment C 117.6 (AF) 60 to 30 Exceeded Admin Limit, valve repaired and returned to 0.046 (AL) months 30 month interval 94.2 (AF) 60 to 30 Exceeded Admin Limit, valve repaired and returned to 9.34 (AL) months 30 month interval X40 X-40_ _

CKV-201.2-68 CK-201.2-68_

Containment Containment_

C (AF) 0.042 (AL) 30 months Exceeded Admin Limit, remained on 30 month interval XS-321 CKV-201.2-71 Containment Gross (AF) 30 months Unquantified gross leakage, valve repaired and kept at 0.042 (AL) 30 month interval 9 of 21

ATTACHMENT 1 NINE MILE POINT UNIT 1 RESPONSE TO NRC REQUEST FOR ADDITIONAL INFORMATION REGARDING THE PROPOSED ONE-TIME EXTENSION OF THE PRIMARY CONTAINMENT INTEGRATED LEAKAGE RATE TEST INTERVAL 2001 Refueling Outage Test Schedule Comments W Interval 30 month fixed Unquantified gross leakage, valve repaired Exceeded Admin Limit, valve replaced and kept at 30 month interval 30 months Unquantified gross leakage, valve repaired and kept at 30 month interval N1R17 Spring 2003 Refueling Outage Penetration Comp ID System Test Test Result Test Schedule Comments (2)

Type (scfh) (1) Interval X-4A CKV-31-01 Feedwater C Gross (AF) 30 month fixed Unquantified gross leakage, valve repaired 3.811 (AL)

X413 CKV-31-02 Feedwater C Gross (AF) 30 month fixed Unquantified gross leakage, valve repaired CKV-31-02 X-4B Few r C8.5 (AL)

Gross (AF) 60 to 30 Unquantified gross leakage, valve replaced and returned 0.174 (AL) months to 30 month interval X-5A CKV-39-04 Emerg. C Gross (AF) 30 months Unquantified gross leakage, valve internals replaced and Cooling 6.5 (AL) kept at 30 month interval Control Rod Gross (AF) Unquantified gross leakage, valve repaired. On IST 24 X-174 CKV-44.3-13 C 085 (AL) 24month test interval 10 of 21

ATTACHMENT 1 NINE MILE POINT UNIT 1 RESPONSE TO NRC REQUEST FOR ADDITIONAL INFORMATION REGARDING THE PROPOSED ONE-TIME EXTENSION OF THE PRIMARY CONTAINMENT INTEGRATED LEAKAGE RATE TEST INTERVAL N1R19, Spring 2007 Refueling Outag Penetration Comp ID System Test Test Result Test Schedule Comments (Z)

Type (scfh) () Interval X-243 RPV Stabilizer D Containment B (AF) 22.424(AL) 120 to 30 Exceeded Admin limit, 0-rings replaced and returned to Access Cover 0.046 months 30 month interval X-4A IV-3 1-07 Feedwater C 17.124 19420(L (AF) month fixed Exceeded Admin limit, valve seats flushed with no 19.424 (AL) improvement, accepted AL leakage value Control Rod 4 1.924 (AF) Exceeded Admin limit, performed minor seat X-174 CKV-44.3-12 Drive C 27.024 (AL) 30 month fixed maintenance, leakage improved to less than admin limit Drive_ 27.024 _ _AL)but still elevated NOTES: (1) AF = As-found leak test; AL = As-left leak test (2) Admin limits are: Type B Tests - 16.1 scfh; Type C Tests - 32.3 scfh (3) Containment penetration test stations provide a single location from which multiple penetrations can be tested at once. If elevated leakage is detected, penetrations can be individually isolated to locate the leaking penetration.

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ATTACHMENT 1 NINE MILE POINT UNIT 1 RESPONSE TO NRC REQUEST FOR ADDITIONAL INFORMATION REGARDING THE PROPOSED ONE-TIME EXTENSION OF THE PRIMARY CONTAINMENT INTEGRATED LEAKAGE RATE TEST INTERVAL Table 2 (RAI-tb)

NMP1 Appendix J Type B Test Schedule Option "B" N1R20 N1R21 N1R22 (ILRT)

Comp ID Penetration # Interval o Last Test Date 03/2009 (2) 03/2011

  • 03/2013 t Escape Airlock X-1B 30/f 5/22/07 1 1 1 Personnel Airlock X-1A 30/f 5/22/07 1 1 1 Equipment Hatch X-1 30/f 4/4/07 N1 1 Drywell Flange 30/f 4/12/07 1 1 1 Tophead Manway 30/f 3/28/07 1 1 1 RPV Stabilizer A X-240 120 3/28/01 1 X X RPV Stabilizer B X-241 120 3/24/07 X X 1 RPV Stabilizer C X-242 120 3/24/07 X X I RPV Stabilizer D X-243 30/p 3/30/07 1 1 1 RPV Stabilizer E X-244 120 3/28/01 1 X X RPV Stabilizer F X-245 120 3/26/01 X 1 X RPV Stabilizer G X-246 120 3/22/03 X I X RPV Stabilizer H X-247 30/p 3/24/07 1 X 1 201-08 I Flange 60 2/16/05 1 X X 201-10 I Flange 120 3/14/05 X X I 201-16 I Flange 120 3/14/05 X X I 201-32 I Flange 120 3/14/05 X X 1 68-01 Cover 30/f 3/24/07 1 1 1 68-01 N Shaft 120 3/24/07 X X 1 68-01 S Shaft 120 3/23/07 X X 1 68-02 Cover 30/f 3/26/07 1 1 1 68-02 W Shaft 120 4/9/05 X 1 X 68-02 E Shaft 120 4/9/05 X 1 X 68-08 I Flange 120 3/12/01 1 X X 68-03 Cover 30/f 3/24/07 1 1 1 68-03 N Shaft 120 4/30/04 1 X X 68-03 S Shaft 120 4/30/04 1 X X 68-09 I Flange 120 2/14/03 X 1 X 68-04 Cover 30/f 5/19/07 1 1 1 12 of 21

ATTACHMENT 1 NINE MILE POINT UNIT 1 RESPONSE TO NRC REQUEST FOR ADDITIONAL INFORMATION REGARDING THE PROPOSED ONE-TIME EXTENSION OF THE PRIMARY CONTAINMENT INTEGRATED LEAKAGE RATE TEST INTERVAL Option "B" NIR20 N1R21 N1R22 (ILRT)

Comp ID Penetration # Interval

  • Last Test Date 03/2009 (2) 03/2011 : 03/2013 (2) 68-04 N Shaft 120 3/26/07 X X X 68-04 S Shaft 120 3/26/07 X X X 68-10 I Flange 120 2/14/03 X 1 X Test Station lE 120 3/5/07 X X X Test Station 2E 120 4/25/01 1 X X Test Station 3E 120 3/15/05 1 X X Test Station 4E 120 3/14/05 X I X Test Station 5E 120 3115105 X 1 X Test Station 6E 120 3/18/05 X I X Test Station 7E 120 3/15/05 X X 1 Test Station 8E 120 2/23/05 X X I Test Station 9E 120 3/5/07 X X X Test Station IM 120 3/11/07 X X X Test Station 2M 120 3/26/05 X X 1 Test Station 3M 120 1/27/03 1 X X Test Station 4M 120 1/30/03 X I X Test Station 5M 120 3/28/03 X I X Test Station 6M 30/f 3/21/07 1 1 1 Test Station 7M 120 3/9/07 X X x Test Station 1IM 120 2/13/03 1 X X Test Station 12M 120 3/17/05 X X 1 TIP #3 X-23B 120 3/27/01 1 X X TIP #4 X-23C 120 3/27/01 1 X X TIP #1 X-23D 120 3/28/03 X 1 X TIP #2 X-23E 120 3/28/03 X_1 X Hatch #1 XS-310 30/f 4/6/07 1 1 1 Ilatch, ,#2 XS-311 30/f 4/6/07 1 1 Hatch #3 XS-312 30/f 4/4/07 1 1 1 58.1-07 Flange 120 3/8/07 X X X 68-01 N Flange 120 3/24/07 X X 1 68-01 S Flange 120 3/24/07 X X 1 68-02 W Flange 120 4/9/05 X 1 X 13 of 21

ATTACHMENT 1 NINE MILE POINT UNIT 1 RESPONSE TO NRC REQUEST FOR ADDITIONAL INFORMATION REGARDING THE PROPOSED ONE-TIME EXTENSION OF THE PRIMARY CONTAINMENT INTEGRATED LEAKAGE RATE TEST INTERVAL Option "B" N1R20 N1R21 NIR22 (ILRT)

Comp ID Penetration # Interval ) Last Test Date 03/2009 t 03/2011 2 03/2013 )

68-02 E Flange 120 4/9/05 X I X 68-03 N Flange 120 4/30/04 1 X X 68-03 S Flange 120 4/30/04 1 X X 68-04 N Flange 120 3/26/07 X X X 68-04 S Flange 120 3/26/07 X X X 81-241 I Flange 30/p 4/1/07 1 1 X 81-242 I Flange 30/p 4/1/07 1 1 X 81-243 I Flange 30/p 3/19/07 1 1 X 81-244 I Flange 30/p 3/20/07 1 1 X Type B Test Totals 33 33 28 NOTES: (1) Option "B" Interval key: 30/f = 30 month fixed interval 30/p = 30 month performance-based interval 60 = 60 month performance-based interval 120 = 120 month performance-based interval (2) Test Schedule Interval key: 1 = Scheduled test; X = Test not scheduled 14 of 21

ATTACHMENT 1 NINE MILE POINT UNIT 1 RESPONSE TO NRC REQUEST FOR ADDITIONAL INFORMATION REGARDING THE PROPOSED ONE-TIME EXTENSION OF THE PRIMARY CONTAINMENT INTEGRATED LEAKAGE RATE TEST INTERVAL Table 3 (RAI-lb)

NMP1 Appendix J Type C Test Schedule Option "B" Last Test N1R20 NIR21 NIR22 (ILRT) Type C Test Comp ID Penetration # Interval

  • Date 03/2009 (2) 03/2011 () 03/2013 2 ILRT Comments ()81-241 XS-335 30/p 4/1/07 1 X 1 Normal lineup 81-242 XS-335 30/p 4/1/07 1 X I Normal lineup 81-243 XS-334 30/p 3/19/07 1 1 X Normal lineup 81-244 XS-334 30/p 3/19/07 1 X I Normal lineup 01-01 X-2A 30/f 3/17/07 1 1 1 ILRT penalty 01-02 X-2B 30/f 3/17/07 1 1 1 ILRT penalty 01-03 X-2A 30/f 3/28/07 1 1 1 ILRT penalty 01-04 X-2B 30/f 3/28/07 1 1 1 ILRT penalty 31-OIR X-4A 24 3/21/07 1 1 1 ILRT penalty 31-02R X-4B 24 3/21/07 1 1 1 ILRT penalty 31-07 X-4A 30/f 3/22/07 1 1 1 ILRT penalty 31-08 X-4B 30/f 3/21/07 1 1 1 ILRT penalty 33-O1R X-154 60 3/23/07 X 1 1 ILRT penalty 33-02R X-9 60 4/7/05 1 X 1 ILRT penalty 33-03 X-154 60 3/23/07 X 1 1 ILRT penalty 33-04 X-9 60 4/17/05 1 X I ILRT penalty 36-147 X-23B 24 3/23/07 1 1 1 Vented 36-148 X-23C 24 3/23/07 1 1 1 Vented 36-149 X-23D 24 3/23/07 1 1 1 Vented 36-150 X-23E 24 3/23/07 1 1 1 Vented 39-03 X-5B 30/p 3/22/07 1 1 1 ILRT penalty 39-04 X-5A 30/p 3/23/07 1 X 1 ILRT penalty 39-05 X-5B 60 3/24/07 X I I ILRT penalty 39-06 X-5A 60 3/30/07 X 1_1 ILRT penalty 39-07R X-3A 60 3/26/07 X 1 1 ILRT penalty 39-09R X-3A 60 3/26/07 X 1 1 ILRT penalty 39-08R X-3B 60 3/26/07 X I 1_ILRT penalty 39-IOR X-3B 60 3/26/07 X I 1 _ ILRT penalty 42.1-02 X-131 24 3/22/07 1 1 1 ILRT penalty 15 of 21

ATTACHMENT 1 NINE MILE POINT UNIT 1 RESPONSE TO NRC REQUEST FOR ADDITIONAL INFORMATION REGARDING THE PROPOSED ONE-TIME EXTENSION OF THE PRIMARY CONTAINMENT INTEGRATED LEAKAGE RATE TEST INTERVAL Option "B" Last Test N1R20 N1R21 N1R22 (ILRT) Type C Test Comp ID Penetration # Interval " Date 03/2009

  • 03/2011 (2) 03/2013 (2) ILRT Comments (3) 42.1-03 X-131 24 3/22/07 1 1 1 ILRT penalty 44.2-15 SDV Vent 60 3/30/07 X 1 X Normal lineup 44.2-16 SDV Vent 60 3/30/07 X 1 X Normal lineup 44.2-17 SDV Drain 60 3/30/07 X 1 X Normal lineup 44.2-18 SDV Drain 60 3/30/07 X 1 X Normal lineup 68-05/ 68-08 XS-313 & XS-317 24 3/27/07 1 1 1 Normal lineup 68-06/ 68-09 XS-314 & XS-318 24 3/24/07 1 1 1 Normal lineup 68-07/ 68-10 XS-316 & XS-320 24 3/27/07 1 1 I Normal lineup 72-479 X-122 60 3/20/07 X_1 I ILRT penalty 72-480 X-122 60 3/20/07 X I I ILRT penalty 83.1-09 X-26 60 4/15/05 1 X I ILRT penalty 83.1-10 X-26 60 4/6/05 1 X 1 ILRT penalty 83.1-11 X-25 60 4/16/05 1 X 1 ILRT penalty 83.1-12/ 83.1-35 X-25 60 4/16/05 1 X I ILRT penalty 110-127 X-139 60 4/4/05 1 X I ILRT penalty 110-128/110-640 X-139 30f 4/12/07 1 1 1 ILRT penalty 114-114 X-121 30p 3/20/07 1 X I Vented 114-116 X-121 60 3/19/07 1 X I Vented 122-03 X-82 60 4/3/07 X I I ILRT penalty 201-07/ 201-08 XS-340 30/f 3/27/07 1 1 1 Vented 201-09/201-10 X-18 30/f 3/27/07 1 1 1 Vented 201-16/201-17 XS-327 30/f 3/27/07 1 1 1 Vented 201-31/201-32 X-19 30/f 4/3/07 1 1 1 Vented 201.1-09 X-19 60 3/23/07 X I X Vented 201.1-11 X-19 60 3/23/07 X 1 X Vented 201.1-14 X-59 60 3/16/05 1 X I Vented 201.1-16 X-59 60 3/16/05 1_X 1 Vcntcd 201.2-03 X-19 60 2/23/07 X 1 X Vented 201.2-06 XS-327 60 2/22/07 X 1 X Vented 201.2-23 XS-321 60 3/16/05 1 X 1 Vented 201.2-24 XS-321 60 3/16/05 1 X I Vented 201.2-29 X-49 60 3/22/07 X 1 X Vented 16 of 21

ATTACHMENT 1 NINE MILE POINT UNIT 1 RESPONSE TO NRC REQUEST FOR ADDITIONAL INFORMATION REGARDING THE PROPOSED ONE-TIME EXTENSION OF THE PRIMARY CONTAINMENT INTEGRATED LEAKAGE RATE TEST INTERVAL Option "B" Last Test N1R20 N1R21 N1R22 (ILRT) Type C Test Comp ID Penetration # Interval ) Date 03/2009 (2) 03/2011 (2) 03/2013 2 ILRT Comments (3) 201.2-30 X-49 60 3/20/07 X I X Vented 201.2-32 X-19 60 2/23/07 X 1 X Vented 201.2-33 XS-327 60 2/22/07 X I X Vented 201.2-39 X-23D 60 3/17/05 1 X 1 Vented 201.2-40 X-23D 60 3/17/05 1 X 1 Vented 201.2-67 X-40 60 2/22/07 X 1 X Vented 201.2-68 X-40 60 2/22/07 X 1 X Vented 201.2-70 XS-321 60 3/16/05 1 X 1 Vented 201.2-71 XS-321 60 3/16/05 1 X I Vented 201.2-109 XS-328 60 8/15/08 X 1 X Vented 201.2-110 XS-328 60 8/15/08 X 1 X Vented 201.2-111 XS-328 60 1/23/07 X I X Vented 201.2-112 XS-328 60 1/23/07 X 1 X Vented 201.7-01 X-64 60 1/23/07 X 1 X Vented 201.7-02 X-64 60 1/23/07 X 1 X Vented 201.7-08 X-134 60 3/19/07 X 1 X Vented 201.7-09 X-134 60 3/19/07 X 1 X Vented 201.7-10 X-20 60 8/20/04 1 X I Vented 201.7-11 X-20 60 8/20/04 1 X 1 Vented 44.3-12 X-174 24 4/2/07 1 1 1 ILRT penalty 44.3-13 X-174 24 3/27/07 1 1 1 ILRT penalty Type C Test Totals 49 59 59 NOTES: (1) Option "B" Interval Key: 24 = IST required test, performed every 24 months 30/f =30 month fixed interval 30/p = 30 month performance-based interval 60 = 60 month performance-based interval (2) Test Schedule Interval Key: 1 = Scheduled test; X = Test not scheduled (3) Type C Test ILRT Comments: Normal Lineup - Component inherently exposed to Type A test pressure Vented - Penetration exposed to Type A test pressure and is vented ILRT Penalty - Penetration not exposed to Type A test pressure, penalty taken. Type C results added to ILRT.

17 of 21

ATTACHMENT 1 NINE MILE POINT UNIT 1 RESPONSE TO NRC REQUEST FOR ADDITIONAL INFORMATION REGARDING THE PROPOSED ONE-TIME EXTENSION OF THE PRIMARY CONTAINMENT INTEGRATED LEAKAGE RATE TEST INTERVAL Table 4 (RAI-ld)

NMP1 Frequently Disassembled Gasketed / Bolted Penetrations Type B Testing Schedule Penetration Description Test Schedule Interval Date Last Tested X-1, Equipment Hatch 30 month fixed 4/04/07 X-127, Drywell Head Manway 30 month fixed 3/28/07 Drywell Flange 30 month fixed 4/12/07 XS-3 10, Torus Access Manway 30 month fixed 4/06/07 XS-31 1, Torus Access Manway 30 month fixed 4/06/07 XS-312, Torus Access Manway 30 month fixed 4/07/07 CKV-68-01, Containment Vacuum Breaker Cover 30 month fixed 3/24/07 CKV-68-02, Containment Vacuum Breaker Cover 30 month fixed 3/26/07 CKV-68-03, Containment Vacuum Breaker Cover 30 month fixed 3/24/07 CKV-68-04, Containment Vacuum Breaker Cover 30 month fixed 5/19/07 PSV-81-241, Safety Valve Flange 30 month performance-based 4/01/07 PSV-81-242, Safety Valve Flange 30 month performance-based 4/01/07 PSV-81-243, Safety Valve Flange 30 month performance-based 3/19/07 PSV-81-244, Safety Valve Flange 30 month performance-based 3/20/07 18 of 21

ATTACHMENT 1 NINE MILE POINT UNIT 1 RESPONSE TO NRC REQUEST FOR ADDITIONAL INFORMATION REGARDING TILE PROPOSED ONE-TIME EXTENSION OF THE PRIMARY CONTAINMENT INTEGRATED LEAKAGE RATE TEST INTERVAL Table 5 (RAI-ld)

NMP1 Infrequently Disassembled Gasketed / Bolted Penetrations Type B Testing Schedule Penetration Description Test Schedule Interval Date Last Tested (All Performance-Based)

X-240, RPV Stabilizer A Access Cover 120 months 3/28/01 X-241, RPV Stabilizer B Access Cover 120 months 3/24/07 X-242, RPV Stabilizer C Access Cover 120 months 3/24/07 X-243, RPV Stabilizer D Access Cover 30 months 3/30/07 X-244, RPV Stabilizer E Access Cover 120 months 3/28/01 X-245, RPV Stabilizer F Access Cover 120 months 3/26/01 X-246, RPV Stabilizer G Access Cover 120 months 3/22/03 X-247, RPV Stabilizer H Access Cover 30 months 3/24/07 IV-58.1-07, Inboard Flange 120 months 3/08/07 IV-201-08, Inboard Flange 60 months 2/16/05 IV-201-10, Inboard Flange 120 months 3/14/05 IV-201-16, Inboard Flange 120 months 3/14/05 IV-201-32, Inboard Flange 120 months 3/14/05 1V-68-08, Inboard Flange 120 months 3/12/01 IV-68-09, Inboard Flange 120 months 2/14/03 IV-68-10, Inboard Flange 120 months 2/14/03 CKV-68-01, Valve Shaft Seals 120 months 3/24/07 19 of 21

ATTACHMENT 1 NINE MILE POINT UNIT 1 RESPONSE TO NRC REQUEST FOR ADDITIONAL INFORMATION REGARDING THE PROPOSED ONE-TIME EXTENSION OF THE PRIMARY CONTAINMENT INTEGRATED LEAKAGE RATE TEST INTERVAL Penetration Description Test Schedule Interval Date Last Tested (All Performance-Based)

CKV-68-02, Valve Shaft Seals 120 months 4/09/05 CKV-68-03, Valve Shaft Seals 120 months 4/30/04 CKV-68-04, Valve Shaft Seals 120 months 3/26/07 TIP #1, Flange 120 months 3/28/03 TIP #2, Flange 120 months 3/28/03 TIP #3, Flange 120 months 3/27/01 TIP #4, Flange 120 months 3/27/01 20 of 21

ATTACHMENT 1 NINE MILE POINT UNIT 1 RESPONSE TO NRC REQUEST FOR ADDITIONAL INFORMATION REGARDING THlE PROPOSED ONE-TIME EXTENSION OF THE PRIMARY CONTAINMENT INTEGRATED LEAKAGE RATE TEST INTERVAL Table 6 (RAI-5)

Summary of Major Changes in the 2007 NMP1 PRA Model and a Qualitative Assessment of Their Importance to Internal Events CDF PRA Model Change Summary CDF Increase CDF Decrease Original Initiating Events More realistic frequency plus added availability -- High Manual Shutdown Initiator Improved modeling (was conservative) --- High High Energy Line Breaks/Floods Added these initiators to model Medium ---

Equipment Reliability Data Data is much improved since the IPE --- Medium Consequential Loss of Offsite Power (LOSP) Increased the probability that trip causes LOSP Medium --

Human Reliability Analysis Improved modeling of dependencies plus Emergency Condenser Medium ---

(EC) control Load Management Improved modeling (was conservative) --- Medium Loss of RPS Buses and Instruments Improved modeling (was conservative) --- Low Unit 2 Firewater Crosstie Added to the model --- Low Station Blackout Model Improved Accident Sequence Model --- Low Success Criteria 2 HPCI versus 1 for MLOCAW and ATWS Low 3 Electromatic Relief Valves (ERVs) versus 2 with firewater Long term makeup to EC for depressurization 21 of 21

ATTACHMENT 2 REVIEW OF THE NMP1 PRA MODEL UPDATE PEER REVIEW FINDINGS (RAI-5)

Nine Mile Point Nuclear Station, LLC December 4, 2008

ATTACHMENT 3 ANNOTATED PAGES FROM ATTACHMENT 2 TO THE NMPNS SUBMITTAL DATED AUGUST 15, 2008 The following annotated pages are provided:

iii 58 B-2 B-3 Nine Mile Point Nuclear Station, LLC December 4, 2008

List of Tables and Figures Table 6-1 COLLAPSED ACCIDENT PROGRESSION BIN (APB) DESCRIPTION [5] ..................................... 10 Table 6-2 CALCULATION OF PEACH BOTTOM (NUREG/CR-4551) POPULATION DOSE ........................ 12 Table 6-3 CALCULATION OF NMPS POPULATION DOSE ADJUSTMENT AT 50 MILES .......................... 13 Table 6-4 CORE DAM AGE FREQUENCIES ........................................................................................................ 14 Table 6-5

SUMMARY

OF NMPS RELEASE FREQUENCY BY CONTAINMENT FAILURE MODE ........ 15 Table 6-6 EPRI CONTAINMENT FAILURE CLASSIFICATIONS ..................................................................... 16 Table 6-7 MAPPING OF PEACH BOTTOM ACCIDENT PROGRESSION BINS ............................................. 17 Table 6-8 MAPPING OF NMPS CONTAINMENT FAILURE MODES TO EPRI RELEASE CLASSES ........... 18 Table 8-1 ACCIDENT CLASS DEFINITIONS ...................................................................................................... 34 Table 8-2 EPRI ACCIDENT CLASS FREQUENCIES BASED ON NMPS PRA - EPRI TR-104285 .................. 35 Table 8-3 POPULATION DOSE ESTIMATES FOR NMPS AT 50 MILES .......................................................... 35 Table 8-4 POPULATION DOSE RATE: 3/10-YR ILRT TEST INTERVAL - EPRI TR-104285 .......................... 36 Table 8-5 POPULATION DOSE RATE: 10-YR ILRT TEST INTERVAL - EPRI TR-104285 ............................ 36 Table 8-6 POPULATION DOSE RATE: 15-YR ILRT TEST INTERVAL - EPRI TR-104285 ............................ 37 Table 8-7

SUMMARY

OF RISK IMPACT OF TYPE A ILRT TEST FREQUENCIES - EPRI TR-104285 ...... 38 Table 9-1 EPRI ACCIDENT CLASS FREQUENCIES FOR NMPS - NEI Interim Guidance ............................... 47 Table 9-2 POPULATION DOSE RATE: 3/10-YR ILRT TEST INTERVAL- NEI Interim Guidance ................ 48 Table 9-3 POPULATION DOSE RATE: 10-YR ILRT TEST INTERVAL - NEI Interim Guidance ...................... 48 Table 9-4 POPULATION DOSE RATE: 15-YR ILRT TEST INTERVAL - NEI Interim Guidance ...................... 49 Table 9-5

SUMMARY

OF RISK IMPACT ON TYPE A ILRT FREQUENCY - NEI Interim Guidance .............. 50 Table 10-1 EPRI ACCIDENT CLASS FREQUENCIES FOR NMPS - EPRI TR-1009325 ................................... 54 Table 10-2 POPULATION DOSE RATE: 3/10-YR ILRT TEST INTERVAL - EPRI TR-1009325 ..................... 55 Table 10-3 POPULATION DOSE RATE: 10-YR ILRT TEST INTERVAL - EPRI TR-1009325 ......................... 56 Table 10-4 POPULATION DOSE RATE: 15-YR ILRT TEST INTERVAL - EPRI TR-1009325 ......................... 56 Table 10-5

SUMMARY

OF RISK IMPACT OF TYPE A ILRT TEST FREQUENCIES - EPRI TR-1009325 ........ 57 Table 12-1 OVERALL

SUMMARY

OF RISK IMPACT OF VARIOUS TYPE A ILRT TEST FREQUENCIES ... 61 Figure A-I: NMPS CONTAINMENT AND TORUS AREA .................................................................................... A-8 Table B-1 CALCULATION OF LERF IMPACT INCLUDING EXTERNAL EVENTS USING NEI INTERIM G U ID AN C E ........................................................................................................................................................ B-2 M SO D E L:....................................................... I....................................................................................................... -.

iii

11. External Event Impacts External hazards were evaluated in the NMPS Individual Plant Examination of External Events (IPEEE) Submittal [26] in response to the NRC IPEEE Program (Generic Letter 88-20 Supplement 4). The IPEEE.Program was a one-time review of external hazard risk to identify potential plant vulnerabilities and to understand severe accident risks. Although the external event hazards in the NMPS IPEEE were evaluated to varying levels of conservatism, the results of the NMPS IPEEE are nonetheless used in this risk assessment to provide a conservative comparison of the impact of external hazards on the conclusions of this ILRT interval extension risk assessment. The proposed ILRT interval extension impacts plant risk in a limited way.

Specifically, the probability of a pre-existing containment leak being the initial containment failure mode given a core damage accident is potentially higher when the ILRT interval is extended. This impact is manifested in the plant risk profile in a similar manner for both internal events and external events. The spectrum of external hazards has been evaluated in the NMPS IPEEE by screening methods with varying levels of conservatism. Therefore, it is not possible at this time to incorporate a realistic quantitative risk assessment of all external event hazards into the ILRT extension assessment. As a result, external events have been evaluated as a sensitivity case to show that the conclusions of this analysis would not be altered if external events were explicitly considered.

The quantitative consideration of external hazards is discussed in more detail in Appendix B of this calculation. As can be seen from Appendix B, if the external hazard risk results of the NMPS IPEEE are included in this assessment (i.e., in addition to internal events), the change in LERE associated with the increase in ILRT interval from 10 years to 15 years is estimated at . E-8/yr based on the most conservative methodology (NEI Interim Guidance). This increase is less than the range of 1E-07/yr to 1E-06/yr, putting it in Region III of the RG 1.174 LERF acceptability curve.

12. Conclusions This section provides the principal conclusions of the ILRT test interval extension risk assessments as reported for the following:
  • Previous generic risk assessment by the NRC
  • NMPS-specific risk assessment for the at-power case, performed using three available methodologies (EPRI TR-104285, NEI Interim Guidance, and EPRI TR-1009325)
  • General conclusions regarding the beneficial effects on shutdown risk 12.1 Previous Assessments The NRC in NUREG-1493 has previously concluded that:
  • Reducing the frequency of Type A tests (ILRTs) from the current three per 10 years to one per 20 years results in an imperceptible increase in risk. The estimated increase in risk is 58

As a sensitivity run, the estimated values for seismic and fire-induced CDF from Sections B.2 and B.3 above were used to calculate the Class 3b frequency. These values were not adjusted for sequences that will independently cause LERF, or will not cause LERF (factors used in other submittals to more accurately characterize the expected LERF from external events associated with the requested ILRT extension).

In order to determine the impact of external events on the proposed ILRT extension request, the impact on LERF was assessed in accordance with the NEI Interim Guidance. The NEI Interim Guidance was used because it yields the most conservative results relative to the other two approaches used in the Probabilistic Safety Assessment calculation.

The impact on the Class 3b frequency due to increases in the ILRT surveillance interval was calculated for external events using the relationships described in Section 6.0. The EPRI Category 3b frequencies for the 3 per 10-year, 10-year and 15-year ILRT intervals were quantified using the total external events CDF. The change in the LERF risk measure due to extending the ILRT interval from 3 in 10 years to 1 in 10 years, or to 1 in 15 years, including both internal and external hazard risk, is provided in Table B-1.

Table B-1 CALCULATION OF LERF IMPACT INCLUDING EXTERNAL EVENTS USING NEI INTERIM GUIDANCE Baseline Case: External Events Class 3b Contribution Assumed to Equal Seismic and Internal Fires CDF 3b LERF LERF LERF 3b 3b Frequency Increase Increase Increase Frequency Frequency (1-per- (3-per-10 (3-per-10 (1-per-10 (3-per-10 (1-per-10 15year to 1-per- to 1-per- to 1-per-year ILRT) year ILRT) ILRT) 10) 15) 15)

External Event Contribution 4.35E-08 1.45E-07 2.18E-07 1.02E-07 1.75E-07 7.27E-08 Internal Event Contribution 9.06E-09 3.03E-08 4.54E-08 2.12E-08 3.64E-08 1.51 E-08 Combined (Internal+External) 5.26E-08 1.76E-07 2.64E-07 1.23E-07 2.IIE-07 8.79E-08 Table B-i shows the sensitivity, under the bounding assumption that the entire external events CDF is applied to the Class 3b frequency, the total estimated increase in LERF is 2.11E-07/yr which is within the range of IE-07/yr to 1E-06/yr (Region II of the RG 1.174 LERF acceptability curve). This study counted the full estimated seismic CDF and full estimated fire CDF against the 3b frequency. Note that the Class 3b frequency calculated for the internal events case (using the NEI Interim Guidance) represents only 1.38% (4.54E-8/yr / 3.30E-6/yr) of the total Internal Events CDF for the 15-year ILRT test interval.

As discussed above, significant conservatisms exist in the risk values used in the external events calculations. This tsgessmont is made more rabust by ineluding ihe sensitivity shown in Tab!

B-2

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" A" 4A aV", 4.'gfl. 64"1 A2614% aan Q = r-1 attfl. ^" 3A + =.16g shcwn in Table B -2. Per Reference B-4, when the calculated increase in LERF due to the proposed plant change is in the range of 1E-7 to IE-6 per reactor year (Region II, "Small Change" in risk), the risk assessment must also reasonably show that the total LERF from all hazards is less than 1E-5/yr. As shown in Reference B-6 the baseline total LERF from all hazards is 1.7E-

06. Based on the LERF increase calculated using the NEI Interim Guidance (i.e., 2.11E-07), the total LERF for the requested change is 1.91E-06/yr. Thus these results meet the LERF criterion of RG 1.174.

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.USR4Gl -2003PRA MOELBE Basclinc Case: ExtcrnaI Events Glass 3b CG,-tributien Gi-en LERF Values Using Old Mcd4-3b LERF 9b n au, .r,-*-cr Fyeu l........ -n n e

- ,*peF. . F.... - .. yeef- .. . peIf, -pef.... t -(I, peFr to Exte.igJ vl n,

. ..... .. If...M-O- 1 C kitcrnal &e'.'c ,..z,,.tl , r- no  ;.96c 0ot i*o 08 G.' 8.6 E0no GecqtributieA -9.9E-G9- - 3 =~-98 -4.6-G- A22-8 E:642O- -. &1E-(InteFrnel 1Externo!) -448G8 S.:;4FG&- 9~4 -G8Ee 4.69E9. -94EQ-Therefore, incorporating external event hazard risk results into this analysis does not change the conclusion of the ILRT Extension risk assessment (i.e., increasing the Nine Mile Point ILRT interval from 3 in 10 years to either 1 in 10 years or 1 in 15 years is an acceptable plant change from a risk perspective).

B.5. References B-1.

Reference:

R. P. Kennedy, "Overview of Methods for Seismic PRA and Margin Analysis Including Recent Innovations", Proceedings of the OECD-NEA Workshop on Seismic Risk, Tokyo, Japan, August, 1999.

B-2. Nine Mile Point Nuclear Generating Plant Unit 1 Quantification Notebook QU Rev 0, December 2007.

B-3

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