ML081280322
| ML081280322 | |
| Person / Time | |
|---|---|
| Site: | Surry  |
| Issue date: | 05/06/2008 |
| From: | Gerald Bichof Virginia Electric & Power Co (VEPCO) |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| 08-0207A | |
| Download: ML081280322 (16) | |
Text
VIRGINIA ELECTRIC AND POWER COMPANY RICHMOND, VIRGINIA 23261 May 6,2008 10 CFR 50.90 U. S. Nuclear Regulatory Commission Serial No. 08-0207A ATTN: Document Control Desk SPS-L1C/BAG R1 Washington, D. C. 20555 Docket No. 50-281 License No. DPR-37 VIRGINIA ELECTRIC AND POWER COMPANY SURRY POWER STATION UNIT 2 PROPOSED LICENSE AMENDMENT REQUEST INTERIM ALTERNATE REPAIR CRITERIA (IARC) FOR STEAM GENERATOR (SG) TUBE REPAIR SUPPLEMENTAL RESPONSE EXIGENT LICENSE AMENDMENT REQUEST By letter dated April 14, 2008 (Serial No. 08-0207), Virginia Electric and Power Company (Dominion) requested an amendment in the form of changes to the Technical Specifications (TS) to Facility Operating License Number DPR-37 for Surry Power Station Unit 2. This amendment request proposes a one cycle revision to the Surry Power Station (SPS) Technical Specification (TS) 6.4.Q, "Steam Generator (SG) Program," and TS 6.6.A.3 "Steam Generator Tube Inspection Report," to incorporate an interim alternate repair criteria into the provisions for SG tube repair criteria during Unit 2 Refueling Outage 21 and the subsequent operating cycle. The letter requested approval of the proposed license amendment by May 14, 2008 to support the spring Unit 2 refueling outage, which was to start in late April 2008.
On April 15, 2008, an "Order and Notice of Consideration of Issuance of Amendment to Facility Operating License, Proposed No Significant Hazards Consideration Determination, and Opportunity for a Hearing and Order Imposing Procedures for Access to Sensitive Unclassified Non-Safeguards Information" for the proposed Surry Unit 2 License Amendment Request was issued by the NRC and notice forwarded to the Office of the Federal Register for publication. On April 25, 2008, the above referenced Order and Notice were published in the Federal Register (Vol. 73/No. 81, page 22443).
Dominion received NRC comments on the submitted amendment request by electronic mail on April 30, 2008 requesting modification of the wording in the proposed Technical Specifications (TS) and a correction to a TS reference in the cover letter. The correct TS reference is stated above (TS 6.6.A.3) and the modification to the TS wording is provided in Attachment 1 to this letter. Please
Serial No. 08-0207A Docket Nos. 50-281 Page 2 of 3 replace the affected pages included in our initial submittal with the replacement pages provided in Attachment 1 as directed therein. The changes are indicated by revision bars in the left hand margin. Dominion has reviewed the changes and determined that the no significant hazards consideration and the environmental assessment included in the April 14, 2008 license amendment request are not affected.
Based upon the unexpected results from steam generator inspections performed during the ongoing Unit 2 refueling outage, it is requested that the proposed license amendment request submitted on April 14, 2008 be reviewed on an exigent basis to support the Unit 2 steam generator inspection and to avoid the unnecessary removal from service of a large number of steam generator tubes that are still capable of performing their design function. The justification and basis for an exigent review of the previously submitted license amendment request is provided in Attachment 2. Dominion respectfully requests NRC approval of the proposed license amendment by May 12, 2008 to support steam generator closure. Once approved, the amendment will be implemented prior to increasing reactor coolant temperature above 200°F during startup of Surry Unit 2 from the refueling outage, currently scheduled for May 18, 2008.
If you have any questions or require additional information, please contact Mr. Gary D. Miller (804) 273-2771.
Sincerely, M7h~i~
Gerald T. Bischof (/
Vice President - Nuclear Engineering COMMONWEALTH OF VIRGINIA COUNTY OF HENRICO The foregoing document was acknowledged before me, in and for the County and Commonwealth aforesaid, today by Gerald T. Bischof, who is Vice President - Nuclear Engineering, of Virginia Electric and Power Company. He has affirmed before me that he is duly authorized to execute and file the foregoing document in behalf of that Company, and that the statements in the document are true to the best of his knowledge and belief.
AcknOWledged before me this Ie ~ day of )n~ ,2008.
My Commission Expires: (~!1&f:;.3 ~ dol!J[3 .
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-NQttiYPUbJic MARGARET B. BENNETT Notary Public 3~¥30~
Commonwealth of Virginia My Commission Expires Aug 31. 2008
Serial No. 08-0207A Docket Nos. 50-281 Page 3 of 3 Commitments made in this letter:
- 1. The amendment, once approved, will be implemented prior to increasing reactor coolant temperature above 200°F during startup of Surry Unit 2 from the refueling outage.
Attachments:
- 1. Replacement Pages for Dominion's April 14, 2008 Proposed License Amendment Request Associated with Interim Alternate Repair Criteria for Steam Generator Tube Repair
- 2. Basis for Exigent Review cc: U.S. Nuclear Regulatory Commission Region II Sam Nunn Atlanta Federal Center 61 Forsyth Street, SW Suite 23T85 Atlanta, Georgia 30303 NRC Senior Resident Inspector Surry Power Station State Health Commissioner Virginia Department of Health James Madison Building - 7th Floor 109 Governor Street Room 730 Richmond, Virginia 23219 Mr. S. P. Lingam NRC Project Manager - Surry and North Anna U. S. Nuclear Regulatory Commission One White Flint North 11555 Rockville Pike Rockville, Maryland 20852 Mr. R. A. Jervey NRC Project Manager U. S. Nuclear Regulatory Commission One White Flint North 11555 Rockville Pike Rockville, Maryland 20852
Serial No. 08-0207A Docket No. 50-281 ATTACHMENT 1 Replacement Pages for Dominion's April 14. 2008 Proposed License Amendment Request Associated with Interim Alternate Repair Criteria for Steam Generator Tube Repair Virginia Electric and Power Company (Dominion)
Surry Power Station Unit 2
Serial No. 08-0207A Docket No. 50-281 Attachment 1 DELETE SUBSTITUTE (from the April 14, 2008 letter) (Revised pages attached)
In Enclosure 1 - Discussion of Change In Enclosure 1 - Discussion of Change
- Page 2 of 15
- Page 2 of 15
- Page 13 of 15
- Page 13 of 15 In Enclosure 2 - Proposed Technical In Enclosure 2 - Proposed Technical Specification Pages (Marked-up) Specification Pages (Marked-up)
- Insert A
- Insert A : Proposed Technical Enclosure 3: Proposed Technical Specifications Pages (Typed) Specifications Pages (Typed)
- Technical Specification pages TS 6.4-12
- Technical Specification pages TS 6.4-12 and TS 6.4-13 and TS 6.4-13
Serial No. 08-0207A Docket No. 50-281 Attachment 1 Replacement Pages for Enclosure 1 to Dominion's April 14, 2008 License Amendment Request Discussion of Change Virginia Electric and Power Company (Dominion)
Surry Power Station Unit 2
Serial No. 08-0207A Docket No. 50-281 Attachment 1 203 degrees found in the portion of the tube below 17 inches from the top of the tubesheet and above 1 inch from the bottom of the tubesheet shall be removed from service.
Tubes with service-induced flaws located within the region from the top of the tubesheet to 17 inches below the top of the tubesheet shall be removed from service. Tubes with service-induced axial cracks found in the portion of the tube below 17 inches from the top of the tubesheet do not require plugging.
When more than one flaw with circumferential components is found in the portion of the tube below 17 inches from the top of the tubesheet and above 1 inch from the bottom of the tubesheet with the total of the circumferential components greater than 203 degrees and an axial separation distance of less than 1 inch, then the tube shall be removed from service. When the circumferential components of each of the flaws are added, it is acceptable to count the overlapped portions only once in the total of circumferential components.
When one or more flaws with circumferential components are found in the portion of the tube within 1 inch from the bottom of the tubesheet, and the total of these circumferential components exceeds 94 degrees, then the tube shall be removed from service. When one or more flaws with circumferential components are found in the portion of the tube within 1 inch from the bottom of the tubesheet and within 1 inch axial separation distance of a flaw above 1 inch from the bottom of the tubesheet, and the total of these circumferential components exceeds 94 degrees, then the tube shall be removed from service. When the circumferential components of each of the flaws are added, it is acceptable to count the overlapped portions only once in the total of circumferential components.
- TS 6.6.A.3 - Steam Generator Tube Inspection Report TS 6.6.A.3 currently states:
"A report shall be submitted within 180 days after T avg exceeds 200°F following completion of an inspection performed in accordance with the Specification 6.4.0, Steam Generator (SG) Program. The report shall include:
- a. The scope of inspections performed on each SG,
- b. Active degradation mechanisms found,
- c. Nondestructive examination techniques utilized for each degradation mechanism,
- d. Location, orientation (if linear), and measured sizes (if available) of service induced indications, 2 of 15
Serial No. 08-0207A Docket No. 50-281 Attachment 1 (3) Does the proposed change involve a significant reduction in a margin of safety?
Response: No The proposed change maintains the required structural margins of the steam generator tubes for both normal and accident conditions. NEI 97-06, Rev. 2 and RG 1.121 are used as the basis in the development of the limited tubesheet inspection depth methodology for determining that steam generator tube integrity considerations are maintained within acceptable limits. RG 1.121 describes a method acceptable to the NRC stafffor meeting GDC 14, 15,31, and 32 by reducing the probability and consequences of an SGTR. RG 1.121 concludes that by determining the limiting safe conditions of tube wall degradation beyond which tubes with unacceptable cracking, as established by inservice inspection, should be removed from service or repaired, the probability and consequences of a SGTR are reduced. This RG uses safety factors on loads for tube burst that are consistent with the requirements of Section III of the ASME Code.
For axially oriented cracking located within the tubesheet, tube burst is precluded due to the presence of the tubesheet. For circumferentially oriented cracking in a tube or the tube-to-tubesheet weld, Reference 6 defines a length of remaining tube ligament that provides the necessary resistance to tube pullout due to the pressure induced forces (with applicable safety factors applied). Additionally, it is shown that application of the limited tubesheet inspection depth criteria will not result in unacceptable primary-to-secondary leakage during all plant conditions.
Based on the above, it is concluded that the proposed changes do not result in any reduction of margin with respect to plant safety as defined in the Updated Final Safety Analysis Report or bases of the plant Technical Specifications.
Therefore, Dominion concludes that the proposed amendment presents no significant hazards consideration under the standards set forth in 10 CFR 50.92(c) and, accordingly, a finding of "no significant hazards consideration" is justified.
4.3 Precedents Wolf Creek Nuclear Operating Corporation and Vogtle Electric Generating Plant were granted similar TS changes on April 4, 2008 and April 9, 2008, respectively. These changes modified the inspection requirements for portions of the SG tubes greater than 17 inches below the top of the tubesheet.
SNC was previously granted similar TS changes. One was granted on September 12, 2006 (Reference 1) that involved a one-time change to TS 5.5.9, "Steam Generator (SG) Tube Surveillance Program," regarding the required SG inspection scope for Vogtle, Unit 1, during Refueling Outage 13 and the subsequent operating cycle and Vogtle, Unit 2, during Refueling Outage 12, and the subsequent operating cycle. The other change was granted on September 21,2005 (Reference 10) that involved a one-time change to TS 5.5.9, "Steam Generator (SG) Tube Surveillance Program,"
13 of 15
Serial No. 08-0207A Docket No. 50-281 Attachment 1 Replacement Pages for Enclosure 2 to Dominion's April 14, 2008 License Amendment Request Proposed Technical Specifications Pages (Marked-up)
Virginia Electric and Power Company (Dominion)
Surry Power Station Unit 2
Serial No. 08-0207A Docket No. 50-281 Attachment 1 INSERT A -Insert as new paragraph in TS 6.4.0.3 on page TS 6.4-12:
The following alternate tube repair criteria shall be applied as an alternative to the 40% depth-based criteria:
- a. For Unit 2 Refueling Outage 21 and the subsequent operating cycle, tubes with flaws having a circumferential component less than or equal to 203 degrees found in the portion of the tube below 17 inches from the top of the tubesheet and above 1 inch from the bottom of the tubesheet do not require plugging.
Tubes with flaws having a circumferential component greater than 203 degrees found in the portion of the tube below 17 inches from the top of the tubesheet and above 1 inch from the bottom of the tubesheet shall be removed from service.
Tubes with service-induced flaws located within the region from the top of the tubesheet to 17 inches below the top of the tubesheet shall be removed from service. Tubes with service-induced axial cracks found in the portion of the tube below 17 inches from the top of the tubesheet do not require plugging.
When more than one flaw with circumferential components is found in the portion of the tube below 17 inches from the top of the tubesheet and above 1 inch from the bottom of the tubesheet with the total of the circumferential components greater than 203 degrees and an axial separation distance of less than 1 inch, then the tube shall be removed from service. When the circumferential components of each of the flaws are added, it is acceptable to count the overlapped portions only once in the total of circumferential components.
When one or more flaws with circumferential components are found in the portion of the tube within 1 inch from the bottom of the tubesheet, and the total of these circumferential components exceeds 94 degrees, then the tube shall be removed from service. When one or more flaws with circumferential components are found in the portion of the tube within 1 inch from the bottom of the tubesheet and within 1 inch axial separation distance of a flaw above 1 inch from the bottom of the tubesheet, and the total of these circumferential components exceeds 94 degrees, then the tube shall be removed from service. When the circumferential components of each of the flaws are added, it is acceptable to count the overlapped portions only once in the total of circumferential components.
Serial No. 08-0207A Docket No. 50-281 Attachment 1 Replacement Pages for Enclosure 3 to Dominion's April 14, 2008 License Amendment Request Proposed Technical Specifications Pages (Typed)
TS 6.4-12
- c. The operational LEAKAGE performance criterion is specified in TS 3.1.C and 4.13, "RCS Operational LEAKAGE."
- 3. 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 shall be applied as an alternative to the 40% depth-based criteria:
- a. For Unit 2 Refueling Outage 21 and the subsequent operating cycle, tubes with flaws having a circumferential component less than or equal to 203 degrees found in the portion of the tube below 17 inches from the top of the tubesheet and above 1 inch from the bottom of the tubesheet do not require plugging.
Tubes with flaws having a circumferential component greater than 203 degrees found in the portion of the tube below 17 inches from the top of the tubesheet and above 1 inch from the bottom of the tubesheet shall be removed from service.
Tubes with service-induced flaws located within the region from the top of the tubesheet to 17 inches below the top of the tubesheet shall be removed from service. Tubes with service-induced axial cracks found in the portion of the tube below 17 inches from the top of the tubesheet do not require plugging.
When more than one flaw with circumferential components is found in the portion of the tube below 17 inches from the top of the tubesheet and above 1 inch from the bottom of the tubesheet with the total of the circumferential components greater than 203 degrees and an axial separation distance of less than 1 inch, then the tube shall be removed from service. When the circumferential components of each of the flaws are added, it is acceptable to count the overlapped portions only once in the total of circumferential components.
When one or more flaws with circumferential components are found in the portion of the tube within 1 inch from the bottom of the tubesheet, and the total of these circumferential components exceeds 94 degrees, then the tube shall be removed from service. When one or more flaws with circumferential components are found in the portion of the tube within 1 inch from the bottom of the tubesheet and within 1 inch axial separation distance of a flaw above 1 inch from the bottom of the tubesheet, and the total of these circumferential Amendment Nos.
TS 6.4-13 components exceeds 94 degrees, then the tube shall be removed from service.
When the circumferential components of each of the flaws are added, it is acceptable to count the overlapped portions only once in the total of circumferential components.
- 4. 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. The tube-to-tubesheet weld is not part of the tube. In addition to meeting the requirements of 4.a, 4.b, and 4.c 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.
- b. 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.
- c. 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.
- 5. Provisions for monitoring operational primary to secondary LEAKAGE.
Amendment Nos.
Serial No. 08-0207A Docket No. 50-281 ATTACHMENT 2 Basis for Exigent Review Virginia Electric and Power Company (Dominion)
Surry Power Station Unit 2
Serial No. 08-0207A Docket No. 50-281 Attachment 2 JUSTIFICATION AND BASIS FOR THE EXIGENT CIRCUMSTANCES In accordance with 10 CFR 50.91 (a)(6)(vi), Dominion is providing the following justification and basis regarding the need for an exigent NRC review of the license amendment request submitted to the NRC on April 14,2008 (Serial No. 08-0207). The justification and the basis discuss why the exigency could not be avoided and describes Dominion's best efforts to make a timely application.
In response to 2007 industry operating experience on tubesheet anomalies, Surry modified its inspection activities for the 2007 fall Unit 1 Refueling Outage (RFO) and performed detailed inspections on steam generator tubes in the tubesheet region of Unit 1 B steam generator. In mid-February 2008, data gathered in the 2007 Unit 1 fall RFO on 199 hot leg and 11 cold leg B steam generator tubes was reviewed for tubesheet tube end flaws. Based on Surry's lower operating temperature and its effective degradation years (EDY) of operation, no flaws exceeding the repair criteria were expected and no flaws were found. As a result of this review, similar inspections on the Surry Unit 2 steam generators were planned for the 2008 spring Unit 2 Refueling Outage. Similar to the Unit 1 reasoning, minimal flaws were expected on the Unit 2 steam generator tubes in the tubesheet region.
Although the Unit 1 steam generator inspection results indicated that tubesheet tube flaws may not be an issue at Surry, Dominion followed the progress of interim alternate repair criteria (IARC) development that provided relief from the unnecessary plugging of steam generator tubes with flaws in the tubesheet that exceeded the current Technical Specifications plugging criteria. The IARC evaluation provided the basis for continued operation of tubes exceeding the plugging criteria; however, it also required tube end weld inspections. No qualified inspection techniques were available to perform these weld inspections and, therefore, there was no confidence that the IARC could be implemented.
When the issue on weld inspections was resolved in mid-March 2008, interest in use of the IARC for Surry resumed. Dominion contracted for the applicability determination and use of the tARC and submitted a license amendment request to the NRC on April 14,2008 that also addressed the NRC questions previously received by other licensees on the IARC. With no previous indication of degradation in the tubesheet tube ends, the lower EDY at both Surry units, and the lower Surry operating temperature, there was no basis for an exigent or emergency approval of the IARC license amendment request for Surry Unit 2. Instead, Dominion requested an expedited review similar to other recent industry requests.
At the time of the license amendment request submittal, plants with 2008 spring outages began reporting increased indications in tubesheet tube ends in early April.
However, these were plants with higher EDY; therefore, Surry was not considered to be as susceptible. In mid-April, one plant with similar EDY as Surry performed tubesheet tube inspections and found minimal indications. However, at the end of April, a second plant with similar EDY as Surry found numerous indications in the tubesheet tube ends.
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Serial No. 08-0207A Docket No. 50-281 Attachment 2 As discussed above, when the IARC became available and issues with the weld inspection were resolved, Dominion submitted a license amendment request to include the use of the IARC. The actual need for the IARC was not established until the results of Unit 2 steam generator inspections being performed during the ongoing refueling outage identified indications that were not observed in the Unit 1 B steam generator in 2007.
With the 30-day public review period for the April 14, 2008 Surry license amendment request ending on May 25, 2008, Dominion contacted the NRC on May 2, 2008 to discuss submittal of the NRC requested license amendment changes and the potential request for an exigent review. Subsequent to the May 2,2008 discussion, the results of two of the three Surry Unit 2 steam generator inspections indicate that 54 tubes would require removal from service. Assuming the same results from the third steam generator inspection, approximately 75 tubes would be removed from service. Without the IARC criteria, which have been approved for three other stations, there will be a significant increase in the number of Unit 2 steam generator tubes removed from service, the steam generator tube margin would be reduced unnecessarily, and additional exposure to station personnel would be incurred to plug these tubes.
Currently, Surry Unit 2 has a total of only 45 plugged tubes in all three steam generators.
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