ML072770620

September 2007 Evidentiary Hearing - Applicant Exhibit 10, Letter from Michael P. Gallagher to the NRC Enclosing Amergens Additional Commitments Related to Aging Management Program for the Drywell Shell

ML072770620
Person / Time
Site:	Oyster Creek
Issue date:	02/15/2007
From:	Gallagher M AmerGen Energy Co
To:	Document Control Desk, NRC/SECY
SECY RAS
References
2130-07-20464, 50-219-LR, AmerGen-Applicant-10, RAS 14214, TAC MC7624
Download: ML072770620 (15)

Text

R+5 /,/ý2 14 APPLICANT'S EXH. 10

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n Michael P. Gallagher, PE Vice President License Renewal Projects AmnerGen 2oo Exelon Way KSA/2-E Kennett Square, PA 19349 2130-07-20464 February 15, 2007 Telephone 610.765-5958 www.exeloncorp.com michaelp.gallagher@exeloncorp.com DOCKETED USNRC October 1,2007 (10:45am)

OFFICE OF SECRETARY RULEMAKINGS AND ADJUDICATIONS STAFF An Exelon Company 10 CFR 50 10 CFR 51 10 CFR 54 U.S. NUCLEAR REGULATORY COMMISSION In the Matter of WLOGM "

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Docket No.

• -Q2.9-Official Exhibit No...0 OFFERED by' rjiý isoe Intervenor NRC Staff Otrer IDENTIFIED on **-

Witness/Panel Acton Taken:

DMP" REJECTED WITHDRAWN Reporter/Clerk P

U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555 Oyster Creek Generating Station Facility Operating License No. DPR-16 NRC Docket No. 50-219

Subject:

Additional Commitments Related to the Aging Management Program for the Oyster Creek Drywell Shell, Associated with AmerGen's License Renewal Application (TAC No. MC7624)

References:

1. January 18, 2007 Meeting Between ACRS License Renewal Subcommittee, AmerGen Energy Company, LLC and NRC Staff, related to License Renewal of Oyster Creek Generating Station

2. February 1, 2007 Meeting Between Full ACRS, AmerGen Energy Company, LLC and NRC Staff related to License Renewal of Oyster Creek Generating Station

3. ACRS Letter Dated February 8, 2007, Describing the Outcome of the February 1, 2007 ACRS Review of the Oyster Creek Generating Station License Renewal Application In the Reference 1 meeting, AmerGen Energy Company. LLC (AmerGen) presented detailed information related %to the condition of and aging management program activities for the primary containment drywell shell, as part of AmerGen's efforts to renew the operating license for the Oyster Creek Generating Station (OCGS). The Subcommittee identified several specific issues related to the drywell shell structural analysis and certain aspects of the program proposed by AmerGen to manage aging of the drywell shell for the extended period of operation.

During the full ACRS review of the Oyster Creek License Renewal Application (LRA) in the Reference 2 meeting, AmerGen presented its proposed responses to the issues identified by the Subcommittee in the January 18, 2007 meeting. In its February 1 st presentation, AmerGen made three additional commitments to address these previous Subcommittee items. This letter documents these commitments.

In addition, AmerGen is making a commitment to perform the full scope of drywell sand bed region inspections, consistent with what was performed during the 2006 refueling outage, on a frequency of every other refueling outage. AmerGen believes that this commitment is P41+",

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February 15, 2007 Page 2 of 2 responsive to a recommendation made by NRC Staff at the February 1, 2007 ACRS meeting, which was endorsed by the ACRS in its February 8, 2007 letter to the NRC Chairman.

The details of these four new commitments are provided in the Enclosure to this letter. The ASME Section X1, Subsection IWE Primary Containment Inspection aging management program (commitment 27) is modified to include these new commitments, and to clarify the effect of these new commitments on previously made IWE program commitments.

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 0 * - / S" 07 Michael P. Gallagher Vice President, License Renewal AmerGen Energy Company, LLC

Enclosure:

Regulatory Commitments cc:

Regional Administrator, USNRC Region I USNRC Project Manager, NRR - License Renewal, Safety USNRC Project Manager, NRR - License Renewal, Environmental USNRC Project Manager, NRR - Project Manager, OCGS USNRC Senior Resident Inspector, OCGS Bureau of Nuclear Engineering, NJDEP File No. 05040

February 15, 2007 Enclosure Page 1 of 13 ENCLOSURE - REGULATORY COMMITMENTS The following table Identifies additions being made to item #27 of the License Renewal Commitment List, Table A.5 of the Oyster Creek LRA. Four commitments are being added to the ASME Section XI, Subsection IWE Primary Containment Inspection Program as part of this submittal. These new commitments are numbered to sequentially follow the commitments made in previous LRA correspondence as part of the IWE Inspection Program. The full set of commitments made as part of the IWE Program is repeated here for convenience. Bold font is used to highlight new information.

In addition, clarifications are made to certain previously made IWE Program commitments to indicate 1) commitments that were completed during the 2006 refueling outage and 2) the effects, if any, of the new commitments on the scope or frequency of previously made commitments. Again, bold font is used to highlight information introduced in this submittal.

UFSAR ITEM NUMBER COMMITMENT SUPPLEMENT ENHANCEMENT OR SOURCE LOCATION IMPLEMENTATION

• _LRA APP. A)

SCHEDULE Existing program is credited. The program will be A.1.27 Prior to the period of Section enhanced to include:

extended operation B.1.27

1. Ultrasonic Testing (UT) thickness measurements of Prior to the period of the drywell shell in the sand bed region will be extended operation performed on a frequency of every 10 years, except (completed during that the initial inspection will occur prior to the period 2006 refueling

27) ASME Section of extended operation and the subsequent outage); then every XI, Subsection IWE inspection will occur two refueling outages after the other refueling initial inspection, to provide early confirmation that outage thereafter corrosion has been arrested. The UT measurements will be taken from the inside of the drywell at the same locations where UT measurements were performed in 1996.

The inspection results will be compared to previous I

results. Statistically significant deviations from the

February 15, 2007 Enclosure Page 2 of 13 UFSAR ITEM NUMBER COMMITMENT SUPPLEMENT ENHANCEMENT OR SOURCE LOCATION SIMPLEMENTATION (LRA APP. A)

SCHEDULE 1992, 1994, and 1996 UT results will result in corrective actions that include the following:

Perform additional UT measurements to confirm the readings.

Notify NRC within 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> of confirmation of the identified condition.

Conduct visual inspection of the external surface in the sand bed region in areas where any unexpected corrosion may be detected.

Perform engineering evaluation to assess the extent of condition and to determine if additional inspections are required to assure drywell integrity.

Perform operability determination and justification for operation until next inspection.

These actions will be completed prior to restart from the associated outage.

Note: The frequency for the inspections described In commitment I (above) has been changed to every other refueling outage, in accordance with commitment 21 of the IWE Inspection Program.

2. A strippable coating will be applied to the reactor Refueling outages prior cavity liner to prevent water intrusion into the gap to and during the between the drywell shield wall and the drywell shell period of extended during periods when the reactor cavity is flooded, operation

February 15, 2007 Enclosure Page 3 of 13 UFSAR ITEM NUMBER COMMITMENT SUPPLEMENT ENHANCEMENT OR SOURCE LOCATION IMPLEMENTATION iLRA APP A)

SCHEDULE

3. The reactor cavity seal leakage trough drains and the drywell sand bed region drains will be monitored for leakage.

" The sand bed region drains will be monitored daily during refueling outages. If leakage is detected, procedures will be in place to determine the source of leakage and investigate and address the impact of leakage on the drywell shell, including verification of the condition of the drywell shell coating and moisture barrier (seal) in the sand bed region and performance of UT examinations of the shell In the upper regions. UTs will also be performed on any areas in the sand bed region where visual inspection indicates the coating is damaged and corrosion has occurred.

UT results will be evaluated per the existing program. Any degraded coating or moisture barrier will be repaired.

These actions will be completed prior to exiting the associated outage.

" The sand bed region drains will be monitored quarterly during the plant operating cycle. If leakage is identified, the source of water will be investigated, corrective actions taken or planned as Periodically Daily during refueling outages Quarterly during non-outage periods I

I

February 15, 2007 Enclosure Page 4 of 13 UFSAR ITEM NUMBER COMMITMENT.

SUPPLEMENT ENHANCEMENT OR SOURCE LOCATION IMPLEMENTATION

.... (LRA APP. A)

SCHEDULE appropriate. In addition, if leakage is detected, the following items will be performed during the next refueling outage:

Inspection of the drywell shell coating and moisture barrier (seal) in the affected bays in the-sand bed region

• UTs of the upper drywell region consistent with the existing program

" UTs will be performed on any areas in the sand bed region where visual inspection indicates the coating is damaged and corrosion has occurred UT results will be evaluated per the existing program Any degraded coating or moisture barrier will be repaired.

4. Prior to the period of extended operation, AmerGen will perform additional visual inspections of the epoxy coating that was applied to the exterior surface of the Drywell shell in the sand bed region, such that the coated surfaces in all 10 Drywell bays will have been inspected at least once: In addition, the Inservice Inspection (ISI) Program will be enhanced to require inspection of 100% of the epoxy coating every 10 years during the period of Prior to the period of extended operation (completed during 2006 refueling outage); then every other refueling outage thereafter

February 15, 2007 Enclosure Page 5 of 13 UFSAR ITEM NUMBER COMMITMENT SUPPLEMENT ENHANCEMENT OR SOURCE LOCATION IMPLEMENTATION (LRA APP. A)

SCHEDULE extended operation. These inspections will be performed in accordance with ASME Section XI, Subsection IWE. Performance of the inspections will be staggered such that at least three bays will be examined every other refueling outage.

Note: The scope and frequency for the inspections described in commitment 4 (above) has been changed to all 10 bays every other refueling outage, in accordance with commitment 21 of the IWE Inspection Program.

5. A visual examination of the drywell shell in the Prior to the period of drywell floor inspection access trenches will be extended operation performed to assure that the drywell shell remains (completed during intact. If degradation is identified, the drywell shell 2006 refueling condition will be evaluated and corrective actions outage) taken as necessary. In addition, one-time ultrasonic testing (UT) measurements will be taken to confirm the adequacy of the shell thickness in these areas.

Beyond these examinations, these surfaces will either be inspected as part of the scope of the ASME Section Xl, Subsection IWE inspection program or they will be restored to the original design configuration using concrete or other suitable material to prevent moisture collection in these areas.

Note: Commitment 5 (above) is supplemented by

February 15, 2007 Enclosure Page 6 of 13 UFSAR ITEM NUMBER COMMITMENT SUPPLEMENT ENHANCEMENT OR SOURCE LOCATION IMPLEMENTATION (ERA APP. A)

SCHEDULE commitments 16 and 20 of the IWE Inspection Program.

6. The coating inside the torus will be visually Every other refueling inspected in accordance with ASME Section XI, outage prior to Subsection IWE, per the Protective Coatings (completed during Program. The scope of each of these inspections 2006 refueling will include the wetted area of all 20 torus bays.

outage) and during the Should the current torus coating system be period of extended replaced, the inspection frequency and scope will, operation as a minimum, meet the requirements of ASME Section Xl, Subsection IWE.

7. AmerGen will conduct UT thickness measurements Every other refueling in the upper regions of the drywell shell every other outage prior to refueling outage at the same locations as are (completed during currently measured.

2006 refueling outage) and during the period of extended operation

8. The IWE Program will be credited for managing corrosion in the Torus Vent Line and Vent Header exposed to an Indoor Air (External) environment.

9. During the next UT inspections to be performed on Prior to the period of the drywell sand bed region (reference AmerGen extended operation 4/4/06 letter to NRC), an attempt will be made to (completed during locate and evaluate some of the locally thinned 2006 refueling

February 15, 2007 Enclosure Page 7 of 13 UFSAR ITEM NUMBER COMMITMENT SUPPLEMENT ENHANCEMENT OR SOURCE LOCATION IMPLEMENTATION (L.RA APP. A)

SCHEDULE areas identified in the 1992 inspection from the outage); then every exterior of the drywell. This testing will be other refueling performed using the latest UT methodology with outage thereafter existing shell paint in place. The UT thickness measurements for these locally thinned areas may be taken from either inside the drywell or outside the drywell (sand bed region) to limit radiation dose to as low as reasonably achievable (ALARA).

Note: Commitment 9 (above) is supplemented by commitments 14 and 21 of the IWE Inspection Program.

10. AmerGen will conduct UT thickness measurements Prior to the period of on the 0.770 inch thick plate at the junction between extended operation the 0.770 inch thick and 1.154 inch thick plates, in and two refueling the lower portion of the spherical region of the outages later drywell shell. These measurements will be taken at four locations using the 6"x6" grid. The specific locations to be selected will consider previous operational experience (i.e., will be biased toward areas that have had corrosion or leakage). These measurements will be performed prior tothe period of extended operation and repeated at the second refueling outage after the initial inspection, at the same location. If corrosion in this transition area is greater than areas monitored in the upper drywell, UT inspections in the transition area will be I

performed on the same frequency as those in the

February 15, 2007 Enclosure Page 8 of 13 UFSAR ITEM NUMBER COMMITMENT SUPPLEMENT ENHANCEMENT OR SOURCE LOCATION IMPLEMENTATION (IRA APP. A)

SCHEDULE upper drywell (every other refueling outage).

11. AmerGen will conduct UT thickness measurements Prior to the period of in the drywell shell "knuckle" area, on the 0.640 inch extended operation thick plate above the weld to the 2.625 inch thick and two refueling plate. These measurements will be taken at four outages later locations using'the 6"x6" grid. The specific locations to be selected will consider previous operational experience (i.e., will be biased toward areas that have had corrosion or leakage). These measurements will be performed prior to the period of extended operation and repeated at the second refueling outage after the initial inspection, at the same location. If corrosion in this transition area is greater than areas monitored in the upper drywell, UT inspections in the transition area will be performed on the same frequency as those in the upper drywell (every other refueling outage).

12. When the sand bed region drywell shell coating Prior to the period of inspection is performed (item 27, commitments 4 extended operation and 21), the seal at the junction between the sand (completed during bed region concrete and the embedded drywell shell 2006 refueling will be inspected per the Protective Coatings outage); then every Program.

other refueling Note: The frequency for the inspections outage thereafter described In commitment 12 (above) has been I

changed to every other refueling outage, in

February 15, 2007 Enclosure Page 9 of 13 UFSAR ITEM NUMBER COMMITMENT SUPPLEMENT ENHANCEMENT OR SOURCE LOCATION IMPLEMENTATION (LRA APP. A)

SCHEDULE accordance with commitment 21 of the IWE Inspection Program.

13. The reactor cavity concrete trough drain will be verified to be clear from blockage once per refueling cycle. Any identified issues will be addressed via the corrective action process.

14. UT thickness measurements will be taken from outside the drywell in the sandbed region during the 2008 refueling outage on the locally thinned areas examined during the October 2006 refueling outage.

The locally thinned areas are distributed both vertically and around the perimeter of the drywell in all ten bays such that potential corrosion of the drywell shell would be detected.

Note: The frequency for the inspections described in commitment 14 (above) has been changed to every other refueling outage, in accordance with commitment 21 of the IWE Inspection Program.

15. Starting In 2010, drywell shell UT thickness measurements will be taken from outside the drywell in the sandbed region in two bays per outage, such that inspections will be performed in all 10 bays Once per refueling cycle During the 2008 refueling outage and every other refueling outage thereafter All 10 bays will be inspected during the 2008 refueling outage and every other I

February 15, 2007 Enclosure Page 10 of 13 UFSAR ITEM NUMBER COMMITMENT SUPPLEMENT ENHANCEMENT OR SOURCE OCATION IMPLEMENTATION 1L RA AP P. A)

SCHEDULE within a 10-year period. The two bays with the most locally thinned areas (bay #1 and bay #13) will be inspected in 2010. If the UT examinations yield unacceptable results, then the locally thinned areas in all 10 bays will be inspected in the refueling outage that the unacceptable results are identified.

Note: The scope and frequency for the inspections described in commitment 15 (above) have been changed to all 10 bays every other refueling outage, in accordance with commitment 21 of the IWE Inspection Program.

16. Perform visual Inspection of the drywell shell inside the trenches in bay #5 and bay #17 and take UT measurements inside these trenches in 2008 at the same locations examined in 2006. Repeat (both the UT and visual) inspections at refueling outages during the period of extended operation until the trenches are restored to the original design configuration using concrete or other suitable material to prevent moisture collection in these areas.

Note: Commitment 16 (above) is supplemented by commitment 20 of the IWE Inspection Proqram.

refueling outage thereafter.

During the 2008 refueling outage and subsequent refueling outages until trenches are restored to original configuration

February 15, 2007 Enclosure Page 11 of 13 UFSAR ITEM NUMBER COMMITMENT SUPPLEMENT ENHANCEMENT OR SOURCE LOCATION IMPLEMENTATION (LRA APP. A)

SCHEDULE

17. Perform visual inspection of the moisture barrier In accordance with between the drywell shell and the concrete ASME Section Xl, floor/curb, installed inside the drywell during the Subsection IWE October 2006 refueling outage, in accordance with ASME Section XI, Subsection IWE during the period of extended operation.

18. AmerGen will perform a 3-D finite element Prior to the period of structural analysis of the primary containment extended operation drywell shell using modern methods and current drywell shell thickness data to better quantify the margin that exists above the Code required minimum for buckling. The analysis will include sensitivity studies to determine the degree to which uncertainties in the size of thinned areas affect Code margins. If the analysis determines that the drywell shell does not meet required thickness values, the NRC. will be notified in accordance with 10 CFR 50 requirements.

19. AmerGen will perform an engineering study to Prior to the period of investigate cost-effective replacement or repair extended operation options to eliminate or reduce reactor cavity liner leakage.

20. AmerGen Is committed to perform visual and UT Every refueling

.inspections of the drywell shell in the inspection outage until trenches I

trenches in drywell bays 5 and 17 during the are restored

February 15, 2007 Enclosure Page 12 of 13 I

UFSAR ITEM NUMBER COMMITMENT SUPPLEMENT ENHANCEMENT OR SOURCE LOCATION IMPLEMENTATION (LRA APP. A)

SCHEDULE Oyster Creek 2008 refueling outage (see commitment 16 of AmerGen's IWE Program (item 27), made in its letter 2130-06-20426).

AmerGen will extend this commitment and also perform these Inspections during the 2010 refueling outage. In addition, AmerGen will monitor the two trenches for the presence of water during refueling outages. Visual and UT inspections of the shell within the trenches will continue to be performed until no water is identified in the trenches for two consecutive refueling outages, at which time the trenches will be restored to their original design configuration (e.g., refilled with concrete) to minimize the risk of future corrosion.

21. Perform the full scope of drywell sand bed region inspections prior to the period of extended operation and then every other refueling outage thereafter. The full scope is defined as:

UT measurements from inside the drywell (commitment 1)

• Visual inspections of the drywell external shell epoxy coating in all 10 bays (commitment 4)

" Inspection of the seal at the junction between the sand bed region concrete and the embedded drywell shell (commitment During the 2008 refueling outage and every other refueling outage thereafter. If the analysis being performed under commitment 18 above establishes increased margin, or if ongoing inspections continue to demonstrate that drywell shell

February 15, 2007

. Enclosure Page 13 of 13 UFSAR ITEM NUMBER COMMITMENT SUPPLEMENT ENHANCEMENT OR SOURCE LOCATION IMPLEMENTATION

_LRA APP. A)

SCHEDULE

12) corrosion has been UT measurements at the external locally sufficiently arrested, thinned areas inspected in 2006 the period between (commitments 9 and 14) inspections may be increased to minimize personnel 1 radiation exposure.

I