05000368/LER-2009-003, Steam Generator Tube Exceeding Technical Specification Plugging Criteria Remained in Service During Previous Cycles as a Result of the Failure to Use Proper Independent Verification

Steam Generator Tube Exceeding Technical Specification Plugging Criteria Remained in Service During Previous Cycles as a Result of the Failure to Use Proper Independent Verification

ML093090682
Person / Time
Site:	Arkansas Nuclear
Issue date:	11/05/2009
From:	David Bice Entergy Operations
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
2CAN110902 LER 09-003-00
Download: ML093090682 (6)

LER-2009-003, Steam Generator Tube Exceeding Technical Specification Plugging Criteria Remained in Service During Previous Cycles as a Result of the Failure to Use Proper Independent Verification

Event date:
Report date:
Reporting criterion:	10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications 10 CFR 50.73(a)(2)(i) 10 CFR 50.73(a)(2)(vii), Common Cause Inoperability 10 CFR 50.73(a)(2)(ii)(A), Seriously Degraded 10 CFR 50.73(a)(2)(viii)(A) 10 CFR 50.73(a)(2)(ii)(B), Unanalyzed Condition 10 CFR 50.73(a)(2)(viii)(B) 10 CFR 50.73(a)(2)(iii) 10 CFR 50.73(a)(2)(ix)(A) 10 CFR 50.73(a)(2)(iv)(A), System Actuation 10 CFR 50.73(a)(2)(x) 10 CFR 50.73(a)(2)(v)(A), Loss of Safety Function - Shutdown the Reactor 10 CFR 50.73(a)(2)(v)(B), Loss of Safety Function - Remove Residual Heat 10 CFR 50.73(a)(2)(i)(A), Completion of TS Shutdown 10 CFR 50.73(a)(2)(v), Loss of Safety Function
3682009003R00 - NRC Website

text

2CAN110902 November 5, 2009 U. S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555-0001

Subject:

Licensee Event Report 50-368/2009-003-00 Arkansas Nuclear One - Unit 2 Docket No. 50-368 License No. NPF-6

Dear Sir or Madam:

In accordance with 50.73(a)(2)(i)(B), enclosed is the subject report concerning a condition prohibited by the plants Technical Specifications.

There are no commitments contained in this submittal.

Sincerely, DBB/slp Attachment Entergy Operations, Inc.

1448 S.R. 333 Russellville, AR 72802 Tel 479-858-4710 David B. Bice Acting Manager, Licensing Arkansas Nuclear One

2CAN110902 Page 2 cc:

Mr. Elmo Collins Regional Administrator U. S. Nuclear Regulatory Commission Region IV 612 E. Lamar Blvd., Suite 400 Arlington, TX 76011-4125 NRC Senior Resident Inspector Arkansas Nuclear One P.O. Box 310 London, AR 72847 Institute of Nuclear Power Operations 700 Galleria Parkway Atlanta, GA 30339-5957 LEREvents@inpo.org

NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION (9-2007)

LICENSEE EVENT REPORT (LER)

(See reverse for required number of digits/characters for each block)

APPROVED BY OMB NO. 3150-0104 EXPIRES 8/31/2010 the NRC may not conduct or sponsor, and a person is not required to respond to, the information collection.

3. PAGE Arkansas Nuclear One, Unit 2 05000368 1

OF 4

4. TITLE Steam Generator Tube Exceeding Technical Specification Plugging Criteria Remained in Service During Previous Cycles as a Result of the Failure to Use Proper Independent Verification

5. EVENT DATE

6. LER NUMBER

7. REPORT DATE

8. OTHER FACILITIES INVOLVED MONTH DAY YEAR YEAR SEQUENTIAL NUMBER REV NO MONTH DAY YEAR FACILITY NAME DOCKET NUMBER FACILITY NAME 09 08 2009 2009 - 003 - 00 11 05 2009 DOCKET NUMBER

9. OPERATING MODE

11. THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR §: (Check all that apply) 20.2201(b) 20.2203(a)(3)(i) 50.73(a)(2)(i)(C) 50.73(a)(2)(vii) 20.2201(d) 20.2203(a)(3)(ii) 50.73(a)(2)(ii)(A) 50.73(a)(2)(viii)(A) 20.2203(a)(1) 20.2203(a)(4) 50.73(a)(2)(ii)(B) 50.73(a)(2)(viii)(B) 6 20.2203(a)(2)(i) 50.36(c)(1)(i)(A) 50.73(a)(2)(iii) 50.73(a)(2)(ix)(A)

10. POWER LEVEL 20.2203(a)(2)(ii) 50.36(c)(1)(ii)(A) 50.73(a)(2)(iv)(A) 50.73(a)(2)(x) 20.2203(a)(2)(iii) 50.36(c)(2) 50.73(a)(2)(v)(A) 73.71(a)(4) 20.2203(a)(2)(iv) 50.46(a)(3)(ii) 50.73(a)(2)(v)(B) 73.71(a)(5) 20.2203(a)(2)(v) 50.73(a)(2)(i)(A) 50.73(a)(2)(v)(C)

OTHER-Specify in Abstract below or in

D. Corrective Actions

During 2R20 plugging operations, tube SG-B R139, C120 was plugged on the hot leg side, removing the tube from service. The cold leg side of SG-B R140, C119 was also plugged to remove it from service.

A review of the remaining plugged tubes in the ANO-2 steam generators was visually performed and a review of the Arkansas Nuclear One Unit 1 (ANO-1) plugging history was performed. No other discrepancies were identified.

In 2007, Westinghouse process changes, including development of a position verification procedure, independent position tracking, and uniquely identifiable location software upgrades, were instituted as a result of identified potential gaps in the miss-encode prevention barriers.

These changes adequately address the 2005 issues with independent verification.

Additionally, an expectations letter was distributed to Westinghouse SG field services personnel communicating the requirements to verify proper plug locations.

E. Safety Significance

The original flaw was identified in 2R17 (Spring 2005) as a volumetric flaw that measured 43% in depth. The calculated burst pressure for this flaw was > 5300 psi which is well above the NEI 97-06 and ANO-2 SG tube integrity limit of 4050 psi. Accounting for uncertainties, a flaw at 51%

depth is still below that which would leak under any accident or normal operating limits. This is based on a burst pressure model that uses 95% probability and 50% confidence. In 2R20, the tube was retested with both bobbin and plus point. The tube was clean with the exception of the pre-existing flaw, which was measured at 45% in depth and a conservative burst estimate of

~4900 psi. Statistically, the changes in depth, length, and width, were considered unchanged due to uncertainties in sizing methodologies and remained above the tube integrity limit of 4050 psi.

This SG tube would have met all of its intended safety functions. There were no challenges to nuclear safety, industrial safety, or radiological safety.

F. Basis for Reportability Technical Specification (TS) 3.4.5 b. states that all SG tubes satisfying the tube repair criteria shall be plugged in accordance with the Steam Generator Program. The failure to plug the correct tube during the previous refueling outage is a violation of the ANO-2 TSs and the identified condition is reportable under 10 CFR 50.73(a)(2)(i)(B) as an operation or condition prohibited by TSs.

G. Additional Information

There were no previous similar events reported as Licensee Event Reports by ANO.