ML20217M760

Summary of 970725 Meeting W/Gpu in Rockville,Md to Discuss Licensee Plans for Inspecting SG Tubing in Upcoming Refueling Outage

ML20217M760
Person / Time
Site:	Three Mile Island
Issue date:	08/21/1997
From:	Buckley B NRC (Affiliation Not Assigned)
To:	NRC (Affiliation Not Assigned)
References
NUDOCS 9708250273
Download: ML20217M760 (32)

Text

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. 4 . , August 21s 1997 LICENSEE: GPU Nuclear Corporation FACILITY: Three Mile Island, Unit 1

SUMMARY

OF JULY 25. 1997. MEETING RE: INSPECTION OF KINETICALLY EXPANDED JOINTS IN THE ST6AM GENLRATOR UPPER TUBESHEET On July 25. 1997, the NRC staff held a meeting at the NRC offices in i Rockville. Maryland, with GPU Nuclear Corporation, the licensee for Three Mile Island. Unit 1 (TMI-1), to discuss the licensee's plans for inspecting steam generator tubing in an upcoming refueling outage. Specifically the focus of tne meetirn was to discuss the licensee's )lans for inspecting kinetically expanded joints in the upper tubesheet. T1e licensee for THI-l will com)lete l steam generator tube inspection during the upcoming refueling outage (121 1

Outage) scheduled for September 1997. The list of meeting attendees is .

included as Enclosure 1. Enclosure 2 is a copy of the slides presented by the licensee at the meeting.

l In 1981, a primary coolant chemistry excursion damaged a number of tubes in the upper tubesheet area in the 1M1 once through steam generators. A repair l method was implemented that involved kinetically expanding tubes in the upper tubesheet to return-degraded tubes to service. The licensee's presentation curing the meeting focused on its plans for inspecting the kinetic expansion joints in the upper tubesheet and dispositioning indications identified during these inspections. To support the inspection acceptance criteria, the licensee completed analyses to assess the structural integrity of degraded kinetic expansion joints. in addition to presenting the details of the structural assessment, the licensee also discussed the planned scope of inspection for the 12R Outage.

At the conclusion of the licensee's presentation. the NRC staff stated that the licensee's efforts to address degradation in the kinetic expansion joints are encouraging. The staff requested that the licensee submit, when completed details of the structural assessment 3 resented during the meeting and the leakage asscssment that was ongoing at t1e time. Also, the licensee was requested to submit a license amendment as soon as possible to address a revision to the offsite dose calculation to address potential leakage from degradation in the kinetic expansion joints.

Original signed by Bart C. Buckley. Senior Project Manager Project Directorate I-3 Division of Reactor Projects - 1/II Docket No. 50 289

Enclosures:

As stated \

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NAME E3uckley 4 ' * ' EDunningtce (* *fb , REAM t DATE a08/l2 / /97 08/21/97 08/()\/97 08/ /97 i 9700250273 970821 lH ic3AL A CORD coPt \

PDR ADOCK 05000289

Three Milo Island Nuclear Station, Unit No. I cc:

Michael Ross Robert B. Borsum Director, C&M, TM1 BW Nuclear Technologies GPU Nuclear Corporation Suite 525 P.O. Box 480 1700 Rockville Pike Middletown, PA 17057 Rockville, MD 20852 John C. Fornicola William Dornsife, Acting Director Director, Planning and Bureau of Radiation Protection Regulatory Affairs Pennsylvania Department of GPU Nuclear Corporation Environmental Resources 100 Interpace Parkway -P.O. Box 2063 Parsippany, NJ 07054 Harrisburg, PA 17120 Jack S. Wetmore Dr. Judith Johnsrud Manager, TMI Regulatory Affairs National Energy Comittee GPU Nuclear Corporation Sierra Club P.O. Box 480 433 Orlando Avenue Middletown, PA 17057 State College, PA 16803 Ernest L. Blake, Jr., Esquire Mr. James W. Langenbach Shaw, Pittman, Potts & Trowbridge Vice President and Director, TMI 2300 N Street, NW. GPU Nuclear Corporation Washington, DC 20037 P.O. Box 480 Middletown, PA 17057 Chairman Board of County Commissioners of Dauphin County Dauphin County Courthouse Harrisburg, PA 17120 l Chairman Board of Supervisors of Londonderry Township R.D. #1, Geyers Church Road Middletown, PA 17057 Michele G. Evans Senior Resident Inspector (TMI-1)

(l.S. Nuclear Regulatory Commission P.O. Box 311 Middletown, PA 17057 Regional' Administrator, Region I U.S. Nuclear Regulatory Commission 475 Allendale Road.

King of Prussia, PA 19406

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t DISTRIBUTION HARD COPY E-MAR

' FM 1a(SJC1)(FJM) fC hf n 9 880ger (8AB2)

OGC REaton (RBEI)

ACRS E0unnington (ETO)

Dross (SLM3)

TSullivan (EJS)

KKarwoski (KJKI)

PRush (PJRI)

SCoffin (SMCI) 4 I

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o List of Attendees GPU MEETING - THI-1 July 25, 1997 ILT_E AEflL Bart Buckley NRC/NRR S. D. Leshnoff GPUN Ted Sullivan NRC/NRR/DE Ken Karwoski NRC/NRR/DE Phillip Rush NRR/DE/EMCB Stephanie Coffin NRR/DE/EMCB

Bob Knight GPUN Licensing Gene Navratil GPUN NDE/ISI Rick Barley GPUN Nick Trikouros GPUN Julien Abramovici GPUN David Stellfox McGraw Hill 1

Jeff Brown FTI Rich Freeman GPUN Patrick Walsh GPUN Bonnie Williamson Nucleonics Week ENCLOSURE 1 U

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Meeting Objectives i

TMI Plans for Kinetic Expansion Examinations and Disposition ofIndications During 12R Demonstrate Assurance that the OTSG Kinetically Expanded Region Satisfies Safety Criteria for MSLB Accident i

EPCLOSURE 2

r Agenda .

1

Background

Pat Walsh - Director, Equipment Reliability Strategy for 12R Pat Walsh - Director, Equipment Reliability Structural and Leakage Criteria Steve Leshnoff- Consulting Engineer, Engineering Support NDE Plans Gene Navratil-ISI Specialist Material Condition Assessment Steve Leshnoff- Consulting Engineer, Engineering Support Summary Pat Walsh - Director, Equipment Reliability Discussion

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Background. -

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- PresentTech Specs and NUREG-1019 did not require continued examinations of the expanded area after 6R

- NRC evaluations in 1984 recognized that the " repaired and remaining tubes" contain ECT indications but did not require continued examinations after 6R

- 5M and 6R Examinations of the Kinetic Expansion Area showed indications in expanded zone

- GPUN agreed to additional inspections within the upper tubesheet during the 12R Outage and to define acceptable criteria for these inspections

Strategy for 12R -

Since we expect indications in the expanded region of the tubesheet, our analysis  !

justifies the presence of flaws The length of the qualified zone and the extent ofindications that are allowed to remain in service will meet the structural integrity required and leakage criteria for a MSLB

_ _ _ _ _ _ _ _ _ _ _ _ _ _ . _ . _ _ . _ . _ . . ~

Kinetic Expansion Inspection Criteria Development GPCK Has Developed Inspection Criteria for Use During ECT Inspection of TMI-1 OTSG Tubes Within the Kinetically Expanded Regions.

Four Tasks Are Involved:

Kinetic Expansion Inspection Criteria Development .

1. StructuralIntegrity A. Minimum Intact Expansion Determination B. Maximum Acceptable Defect Determination

2. XDE Performance Evaluation

3. Primary-To-Secondary Leakage Analysis

4. Material Condition Assessment

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Kinetic Expansion Inspection Criteria Development

1. StructuralIntegrity "No Slip" for tube.withinjoint "No Parting" for circumferential defect 2.NDE Conservative Disposition & Detennination of Leakage Contributors

3. Primary-To-Secondary Leakage Maintain Possible Accident Leakage To Within a "Small Fraction" of 10 CFR 100 Limits

4. Material Condition No Predicted Growth OfIndications During Operating Cycle

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Structural Integrity- Minimum Intact ~

Expansion to Ensure 'No Slip' Condition "No Slip" condition means no relative movement between ,

expanded tube and tubesheet Analysis Model Results Conservatively Predicts Original Qualification Test Results.

Contact Interference = 0.0003", Coef. Of Friction = 0.2

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Accident Axial Load From SER (NUREG-1019) 3140 lbstused in this analysis 1402 Bsr derived in more recent FTI calculation l

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e Joint Performance '

l Contact Pressure Is Reduced Under Accident Axial Load Reduction Is Greatest Near Expansion Transition Poisson Contraction Contribution ofFilction Reaction Yield Strength Limited Performance for Longer Expansions at Maximum Load Friction Limited Performance for Shorter Expansions at Loads Less than or Equal to the Yield Strength

e Joint Performance .

Accident Condition Produces Displacement Controlled Load. For Lower Yield Strength Tube Material Use Axial Load at 0.16% Axial Strain.

Reduction in Applied Axial Load Include Tube Internal Pressure (Pressure Tightening)

Minimum Necessary Intact Length Is Much Less Than Qualification Length

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l Joint Performance Example: Impact of Axial Flaw on Contact Pressure Direct and Indirect Influence for Through -Wall Flaw Equivalent 4" Expansion Is Formed by 2" Axial Flaw in 6" Expansion Basis for Consideration of Circumferential Flaws, Also, in Terms of Pull-out resistance Edge Effect

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Joint Performance Impact of Tubesheet Bow on Contact Pressure i

- Tubesheet Bow Enlarges Hole and Reduces Contact Interference

- Largest Reduction Occurs at Center of Tube Bundle

- Reduction Is Greater for 22" Expansion Than for 17" Expansion Apply Inspection Criteria Developed for 17" Expansion to 22" Expansion Apply Free Span Criteria to Lower 5" of 22" Expansion

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Structural Integrity - With Respect to-Circumferential Flaws Maximum Acceptable Circumferential Flaw to Ensure "No Parting" Condition Ductile Failure of Through -Wall Flaw (0.64")

Separation Criteria for Multiple Flaws (>1.0" Elevation Difference)

Conservative: No Credit is Taken for Benefit of Friction Reaction in Reducing Axial Load Above Transition

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Kinetic Expansion Inspection Criteria The Inspection Criteria Ensures the Ac equacy of the Joint Independent of the Original Qualification Length.

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Table 1 .

l Inspection Acceptance Criteria for OTSG Kinetic-Expansion Region  ;

1 Tube Bundle Defect Type Required Intact Expansion Location For single tube defects, allowable defect length  !

is 4.4 inches so that the reacired intact Axial expansion is (6"-4.4"=)l .6". For multiple defects, %-inch shall be added to the length of each defect, except the first defect, and the combined defect length shall i,e 4.4 inches or less. Also, for each circumferential defect, a Periphcry defect length of %-inch shall be added.

For single defects, the allowable defect length is 130 degrees or 0.64 inches. For multiple defects:

Circumfereatial

+ If separated axially by less than 1-inch, their length should be combined, and the total shall be less than 0.64-inch.

+ Ifseparated axially be more than 1-inch, the individual defects shall each be less than 0.64-inch in extent. q l

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1 Table 2 ,

I Inspection Acceptance Criteria for OTSG Kinetic-Expansion Region Tube Bundle Defect Type Required Intact Expansion Location The combined allowable defect length is 3.2 inches so that the reauired intact expansion is 2.8 Mid-Radius Axial inches. For each circumferential defect, a defect length of %-inch shall be added.

Circumferential Same as for the tube bundle periphery, as specified above.

The combined allowable defect Center Axial length is 2.8 inches so that the reauired intact expansion is 3.2 inches. For each circumferential defect, a defect length of %-inch shall be added.

Circumferential Same as for the tube bundle periphery, as specified in Table 1.

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Volumetric Indication Bounded by Separate Analysis Results for Axial and Circumferential Defects

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• i Transition Region E se Free Span Disposition Criteria 4

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c Examination Implementation Plan to L se Rotating Technique With

" Super Probe" Head (Plus Point, 0.115" Pancake, and 0.080" HF)

Acquisition of Data From 9" Below Prunary Face Through Kinetic Expansion Transition Analyze Data From Lowest Point Acquired Through E ppermost Required Distance

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Examination Implementation (Continued)

Length / Width Sizing Error For Techniques Bounds All Other Errors and Is Reliable For Structural Disposition

Depth Sizing Will Be Used For Qualitative Evaluation In Leak Rate Calculations (Segregate <

Leak Contributors From Non-Contributors)

In-Situ Leak Testing In Freespan Will Further Confirm Qualitative Leak Contributors

Examination Scope Initial Sample:

100% Of All Inservice 22" Expansions 21% Of AllInservice 17" Expansions

Examination Scope .

(Continued)

Scope Expansion If More Than 1% of Tubes In 3%, 6%, or 12%

Sample Require Repair for Structural Integrity, Increase to 100%

IfLeak Rate Evaluation Determines Unacceptable Results, Increase As Determined by Evaluation

Primary-to-Secondary Leakage Conservative Assumptions Used in Calculation of-Total P/S Leakage All Defects Determined to Be Through-Wall by ECT, Regardless of Location, Are Assumed to Leak As If Located in the Tube Free-Span.

No Credit Is Taken for Remaining Contact Pressure Below the Elevation of the Defect As Added Resistance to Leakage.

L_____

i e, Primary-to-Secondary Leakage

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Evaluation

- Oti-site Dose Will Be Limited to a "Small Fraction" of 10 CFR 100 As Is Presently Included in the Standard Review Plan (SRP 15.1.5, Appendix A). This is the Licensing

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Basis at Other Plants.

A License Change Request'Will Be Submitted Requesting an Increase in Off-site Dose to a "Small Fraction" of 10 CFR 100, (e.g., 30 Rem Thyroid) for MSLB.

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Material Condition Assessment 1

- The Kinetic Expansion Formation Process Results in Bi-Axial Compresdun in the Intact Joint

- Residual Compression Is Not Overcome by Service Loads 1

- Enlargement of Circumferential Defects by Fatigue During Normal Operation Can Be Neglected Even Near the Expansion Transition

- A Representative Sample of Tubes Left in Service With Defects Will Be Re-Inspected In Subsequent Outages in Order to Support Condition Monitoring and Operational Assessment

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• 1 Meeting Summary .

- Kinetic Expansion Inspection Repair Criteria Assure Tube StructuralIntegrity

- PSLR Criteria to Satisfy "Small Fraction" of 10 CFR 100 Dose Limit (License Change Submittal)

- Material Condition Assessed; No Degradation Growth Expected; Continued Monitoring to Assure Inactivity

- Inspect 21% of Kinetic Expansions (Including All 22" Expansions)in 12R

- Sample Escalation If > 1% Require Repair or MSLB Leakage Unacceptable

- NRC Support Will Be Needed to Implement These GPUN Initiatives in 12R