ET 06-0015, Supplement to Revision to Technical Specifications - Steam Generator Tube Integrity Using the Consolidated Line Item Improvement Process

Supplement to Revision to Technical Specifications - Steam Generator Tube Integrity Using the Consolidated Line Item Improvement Process

ML060940425
Person / Time
Site:	Wolf Creek
Issue date:	03/28/2006
From:	Garrett T Wolf Creek
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
ET 06-0015
Download: ML060940425 (10)

Text

i W4LF CREEK 'NUCLEAR OPERATING CORPORATION Terry J Garrett Vice President, Engineering March 28, 2006 ET 06-0015 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555

Reference:

1) Letter ET 05-0021, dated November 3, 2005, from l-. J.

Garrett, WCNOC, to USNRC

2) Letter ET 06-0012, dated February 21, 2006, from l-. J.

Garrett, WCNOC, to USNRC

Subject:

Docket Number 50-482: Supplement to Revision to Technical Specifications - Steam Generator Tube Integrity Using the Consolidated Line Item Improvement Process Gentlemen:

Reference 1 provided Wolf Creek Nuclear Operating Corporation's (WCNOC) application to revise the Technical Specification (TS) requirements related to steam generator tube integrity.

The proposed change was based on NRC-approved Revision 4 to Technical Specification Task Force (TSTF) Standard Technical Specification Change Traveler, TSTF-449, "Steam Generator Tube Integrity."

Reference 2 provided a supplemental revision to Section d. of TS 5.5.9. License Amendment No. 16.2, dated April 28, 2005, approved a one-time change for Refueling Outage 14 and subsequent operating cycle to specify that the portion of the tube below 17 inches from the top of the hot leg tubesheet is excluded from steam generator tube inspections. Reference 1 incorporated in TS 5.5.9 the one-time change approved by Amendment No. 162 as an alternate repair criteria. Additionally, a statement was added to the provisions for steam generator tube inspections (TS 5.5.9, Section d.) indicating that the portion of the tube below 17 inches from the top of the hot leg tubesheet is excluded. However, this statement did not explicitly indicate that this provision was only for Refueling Outage 14 and the subsequent operating cycle. As such, TS 5.5.9, Section d., was revised in Reference 2 to state: "For Refueling Outage 14 and the subsequent operating cycle, the portion of the tube below 17 inches from the top of the hot leg tubesheet is excluded."

P.O. Box 411 / Burlington, KS 66839 1 Phone: (620) 364-8831 An Equal Opportunity Employer M/FIHCNET

ET 06-0015 Page 2 Based on subsequent discussions with the NRC in early March 2006, the following sentence is added to TS 5.5.9 c.1:

"All tubes with degradation identified in the portion of tube within the region from the top of the hot leg tubesheet to 17 inches below the top of the tubesheet shall be removed from service."

Amendment No. 162 included a requirement to plug all tubes found with degradation in the upper *17 inch region of the hot leg tubesheet. Plugging tubes found with degradation is more conservative than the 40 percent plugging limit and will provide added assurance that the length of tubing along the entire proposed 17 inch inspection zone will be effective in resisting tube pull out under tube end cap pressure loads and in resisting primary to secondary leakage between the tube and tubesheet. This additional requirement for Refueling Outage 14 and the subsequent operating cycle that was specified in Amendment No. 162 should have been incorporated as part of the alternate tube repair criteria proposed in Reference 1.

Attachment I and 11provide a Markup of Technical Specification Pages and Retyped Technical Specification pages. The revised TS page in Attachment I to this letter replaces Page 2 of 2 in Attachment I of letter ET 06-0012.

The additional change provided in the Attachments do not impact the conclusions of the No Significant Hazards Consideration provided in Reference 1 since the change is incorporating a requirement that currently exists in the Technical Specifications. In accordance with 10 CFR 50.91, a copy of this submittal is being provided to the designated Kansas State official.

This letter contains no commitments. If you have any questions concerning this matter, please contact me at (620) 364-4084, or Mr. Kevin Moles at (620) 364-4126.

Very truly ours, Terry J. Garrett TJG/rlt Attachments: I - Markup of Technical Specification Pages 11- Retyped Technical Specification Pages cc: T. A. Conley (KDHE), w/a J. N. Donohew (NRC), w/a V\. B. Jones (NRC), w/a B. S. Mallett (NRC), w/a Senior Resident Inspector (NRC), w/a

I STATE OF KANSAS )

) Ss COUNTY OF COFFEY )

Terry J. Garrett, of lawful age, being first duly sworn upon oath says that he is Vice President Engineering of Wolf Creek Nuclear Operating Corporation; that he has read the foregoing document and knows the contents thereof; that he has executed the same for and on behalf of said Corporation with full power and authority to do so; and that the facts therein stated are true and correct to the best of his knowledge, information and belief.

By -ZJ Terry Jgarrett Vice President Engineering SUBSCRIBED and sworn to before me this~nh. day of dS , 2006.

.,O.8 RHON TIEYExXRE Notary Public ihAL My COMMISSION EXPIRES January 11, 2010 Expiration Date o ipyj aa /0

Attachment I to ET 06-0015 r4- Page 1 of 2 ATTACHMENT I MARKUP OF TECHNICAL SPECIFICATION PAGES

Attachment I to ET 06-0015 ____

Page 2 of 2 All 4des  ; c}t~v~eAtlOr d '- forts," of:

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1. For Refueling Outage 14 and the subsequent operating cycle, degradation found in the portion of the tube below 17 inches from the top of the hot leg tubesheet does, not require plugging. *

d. Provisions for SG tube inspections. Periodic SG tube inspections shall be performed. The number and portions of the tubes inspected and methods of inspection shall be performed vwith the objective of detecting flaws of any type (e.g., volumetric flaws, axial and circumferential cracks) that may be present along the length of the tube, from the tube-to-tubesheet weld at the tube inlet to the tube-to-tubesheet weld at the tube outlet, and that may satisfy the applicable tube repair criteria.F/he portion of the tube below 17 inches from the top of the hot leg tubesheet is excluded. The tube-to-tubesheet weld is not part of the tube. In addition to meeting the requirements of d.1, d.2, and d.3 below, the inspection scope, inspection methods, and inspection intervals shall be such as to ensure that SG tube integrity is maintained until the next SG inspection. An assessment of degradation shall be performed to determine the type and location of flaws to which the tubes may be susceptible and, based on this assessment, to determine which inspection methods need to be employed and at what locations. -. I ' ^i4R ho" oiuFh-efri oi

1. Inspect 100% of the tubes in each SG during the first refueling outage following SG replacement.

2. Inspect 100% of the tubes at sequential periods of 120, 90, and, thereafter, 60 effective full power months. The first sequential period shall be considered to begin after the first inservice inspection of the SGs. In addition, inspect 50% of the tubes by the refueling outage nearest the midpoint of the period and the remaining 50%X by the refueling outage nearest the end of the period. No SG shall operate for more than 48 effective full power months or two refueling outages (whichever is less) without being inspected.

3. If crack indications are found in any SG tube, then the next inspection for each SG for the degradation mechanism that caused the crack indication shall not exceed 24 effective full power months or one refueling outage (whichever is less). If definitive information, such as from examination of a pulled tube, diagnostic non-destructive testing, or engineering evaluation indicates that a crack-like indication is not associated with a crack(s), then the indication need not be treated as a crack.

e. Provisions for monitoring operational primary to secondary LEAKAGE.

Attachment II to ET 06-0015 Page 1 of 3 ATTACHMENT II RETYPED TECHNICAL SPECIFICATION PAGES

Programs and Manuals 5.5 5.5 Programs and Manuals 5.5.9 Steam Generator (SG) Program A Steam Generator Program shall be established and implemented to ensure that SG tube integrity is maintained. In addition, the Steam Generator Program shall include the following provisions:

a. Provisions for condition monitoring assessments. Condition monitoring assessment means an evaluation of the "as found" condition of the tubing with respect to the performance criteria for structural integrity and accident induced leakage. The "as found" condition refers to the condition of the tubing during an SG inspection outage, as determined from the inservice inspection results or by other means, prior to the plugging of tubes.

Condition monitoring assessments shall be conducted during each outage during which the SG tubes are inspected or plugged to confirm that the performance criteria are being met.

b. Performance criteria for SG tube integrity. SG tube integrity shall be maintained by meeting the performance criteria for tube structural integrity, accident induced leakage, and operational LEAKAGE.

1. Structural integrity performance criterion: All in-service steam generator tubes shall retain structural integrity over the full range of normal operating conditions (including startup, operation in the power range, hot standby, and cool down and all anticipated transients included in the design specification) and design basis accidents. This includes retaining a safety factor of 3.0 against burst under normal steady state full power operation primaiy-to-secondary pressure differential and a safety factor of 1.4 against burst applied to the design basis accident primary-to-secondary pressure differentials. Apart from the above requirements, additional loading conditions associated with the design basis accidents, or combination of accidents in accordance with the design and licensing basis, shall also be evaluated to determine it the associated loads contribute significantly to burst or collapse. In the assessment of tube integrity, those loads that do significantly affect burst or collapse shall be determined and assessed in combination with the loads due to pressure with a safety factor of 1.2 on the combined primary loads and 1.0 on axial secondary loads.

2. Accident induced leakage performance criterion: The primary to secondary accident induced leakage rate for any design basis accident, other than a SG tube rupture, shall not exceed the leakage rate assumed in the accident analysis in terms of total leakage rate for all SGs and leakage rate for an individual EGG.

Leakage is not to exceed 1 gpm per SG.

(co itinued)

Wolf Creek - Unit 1 5.0-1 1 Amendment No. 423, 159

Programs and Manuals 5.5 5.5 Programs and Manuals 5.5.9 Steam Generator (SG) Program (continued)

3. The operational LEAKAGE performance criterion is specified in LCO 3.4.13, "RCS Operational LEAKAGE."

c. Provisions for SG tube repair criteria. Tubes found by inservice inspection to contain flaws with a depth equal to or exceeding 40% of the nominal tube wall thickness shall be plugged.

The following alternate tube repair criteria may be applied as an alternative to the 40% depth-based criteria:

1. For Refueling Outage 14 and the subsequent operating cycle, degradation found in the portion of the tube below 17 inches from the top of the hot leg tubesheet does not require plugging. All tubes with degradation identified in the portion of tube within the region from the top of the hot leg tubesheet to 17 inches below the top of the tubesheet shall be removed from service.

d. Provisions for SG tube inspections. Periodic SG tube inspections shall be performed. The number and portions of the tubes inspected and methods of inspection shall be performed with the objective of detecting flaws of any type (e.g., volumetric flaws, axial and circumferential cracks) that may be present along the length of the tube, from the tube-to-tubesheet weld at the tube inlet to the tube-to-tubesheet weld at the tube outlet, and that may satisfy the applicable tube repair criteria. For Refueling Outage 14 and the subsequent operating cycle, the portion of the tube below 17 inches from the top of the hot leg tubesheet is excluded. The tube-to-tubesheet weld is not part of the tube. In addition to meeting the requirements of d.1, d.2, and d.3 below, the inspection scope, inspection methods, and inspection intervals shall be such as to ensure that SG tube integrity is maintained until the next SG inspection. An assessment of degradation shall be performed to determine the type and location of flaws to which the tubes may be susceptible and, based on this assessment, to determine which inspection methods need to be employed and at what locations.

1. Inspect 100% of the tubes in each SG during the first refueling outage following SG replacement.

(continued)

Wolf Creek - Unit 1 5.0-1 2 Amendment No. 423, 462

Programs and Manuals 5.5 5.5 Programs and Manuals 5.6.9 Steam Generator (SG) Program (continued)

2. Inspect 100% of the tubes at sequential periods of 120, 90, and, thereafter, 60 effective full power months. The first sequential period shall be considered to begin after the first inservice inspection of the SGs. In addition, inspect 50% of the tubes by the refueling outage nearest the midpoint of the period and the remaining 50% by the refueling outage nearest the end of the period. No SG shall operate for more than 48 effective full power months or two refueling outages (whichever is less) without being inspected.

3. If crack indications are found in any SG tube, then the next inspection for each SG for the degradation mechanism that caused the crack indication shall not exceed 24 effective full power months or one refueling outage (whichever is less). If definitive information, such as from examination of a pulled tube, diagnostic non-destructive testing, or engineering evaluation indicates that a crack-like indication is not associated with a crack(s), then the indication need not be treated as a crack.

e. Provisions for monitoring operational primary to secondary LEAKAGE.

(continued)

Wc If Creek - Unit 1 5.0-1 3 Amendment No. 423,41

Programs and Manuals 5.5 5.5 Programs and Manuals 5.5.10 Secondary Water Chemistry Program This program provides controls for monitoring secondary water chemistry to inhibit SG tube degradation. The program shall include:

a. Identification of a sampling schedule for the critical variables and control points for these variables;

b. Identification of the procedures used to measure the values of the critical variables;

c. Identification of process sampling points, which shall include monitoring the discharge of the condensate pumps for evidence of condenser in leakage;

d. Procedures for the recording and management of data;

e. Procedures defining corrective actions for all off control point chemistry conditions; and

f. A procedure identifying the authority responsible for the interpretation of the data and the sequence and timing of administrative events, which is required to initiate corrective action.

5.5.11 Ventilation Filter Testing Program (VFTP)

A program shall be established to implement the following required testing of Engineered Safety Feature (ESF) filter ventilation systems at the frequencies specified in Regulatory Guide 1.52, Revision 2, and in accordance with the guidance specified below.

a. Demonstrate for each of the ESF systems that an inplace test of the high efficiency particulate air (HEPA) filters shows a penetration and system bypass < 1% when tested in accordance with Regulatory Guide 1.52, Revision 2 at the system flowrate specified below +/- 10%.

ESF Ventilation System Flowrate Control Room Emergency Ventilation System-Filtration 2000 cfm Control Room Emergency Ventilation System-Pressurization 750 cfm Auxiliary/Fuel Building Emergency Exhaust 6500 cfm (continued)

Wolf Creek - Unit 1 5.0-14 Amendment No. 423, 159 I