05000260/LER-2005-008, Re Main Steam Relief Valve Inoperabilty LCO Exceeded During Operating Cycles 11, 12, and 13 as a Result of Lift Setpoint Drift

Re Main Steam Relief Valve Inoperabilty LCO Exceeded During Operating Cycles 11, 12, and 13 as a Result of Lift Setpoint Drift

ML070570288
Person / Time
Site:	Browns Ferry
Issue date:	02/15/2007
From:	O'Grady B Tennessee Valley Authority
To:	Document Control Desk, NRC/NRR/ADRO
References
LER 05-008-00
Download: ML070570288 (11)

LER-2005-008, Re Main Steam Relief Valve Inoperabilty LCO Exceeded During Operating Cycles 11, 12, and 13 as a Result of Lift Setpoint Drift

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
2602005008R00 - NRC Website

text

February 15, 2007 U.S. Nuclear Regulatory Commission 10 CFR 50.73 ATTN: Document Control Desk Mail Stop OWFN, P1-35 Washington, D. C. 20555-0001

Dear Sir:

TENNESSEE VALLEY AUTHORITY - BROWNS FERRY NUCLEAR PLANT (BFN) -

UNIT 2 - DOCKET 50-260 - FACILITY OPERATING LICENSE DPR LICENSEE EVENT REPORT (LER) 50-260/2005-008-000 The enclosed report provides details of past failures to meet the requirements of the Technical Specifications (TS) Limiting Condition for Operation (LCO) 3.4.3 concerning main steam relief valve (MSRV) operability associated with the Unit 2 operating cycles 11, 12, and 13.

Similar MSRV performance prior to calendar year 2001 was reported by TVA to NRC via LER. However, TVA did not report the failure to meet TS following the Unit 2 Cycles 11, 12, and 13 in 2001, 2003 and 2005. The failure to report the occurrences have been addressed by the TVA Corrective Action Program. This LER, 260/2005-008-00, addresses the past conditions (i.e., 2001, 2003, and 2005) which had not been previously reported.

As such, in accordance with 10 CFR 50.73(a)(2)(i)(B), TVA is reporting this as any operation or condition prohibited by the units TS. There are no commitments contained in this letter.

Sincerely, Original signed by:

Brian OGrady cc: See page 2

U.S. Nuclear Regulatory Commission Page 2 February 15, 2007 Enclosure cc (Enclosure):

Ms. Eva A. Brown, Project Manager U.S. Nuclear Regulatory Commission (MS 08G9)

One White Flint, North 11555 Rockville Pike Rockville, Maryland 20852-2739 Ms. Margaret Chernoff, Project Manager U.S. Nuclear Regulatory Commission (MS 08G9)

One White Flint, North 11555 Rockville Pike Rockville, Maryland 20852-2739 Mr. Malcolm T. Widmann, Branch Chief U.S. Nuclear Regulatory Commission Region II Sam Nunn Atlanta Federal Center 61 Forsyth Street, SW, Suite 23T85 Atlanta, Georgia 30303-8931 NRC Resident Inspector Browns Ferry Nuclear Plant 10833 Shaw Road Athens, Alabama 35611-6970

U.S. Nuclear Regulatory Commission Page 3 February 15, 2007 WDC:DTL:BAB Enclosure cc (Enclosure):

M. Bajestani, NAB 1A-BFN A. S. Bhatnagar, LP 6A-C R. H. Bryan, BR 4X-C R. G. Jones, POB 2C-BFN G. V. Little, POB 2C-BFN R. A. DeLong, SAB 1E-BFN K. W. Singer, LP 6A-C P. D. Swafford, LP 6A-C E. J. Vigluicci, WT 6A-K NSRB Support, LP 5M-C INPO:LEREvents@inpo.org EDMS WT CA - K S:lic/submit/subs/ler/2005 008.doc

NRC FORM 366 (7-2001)

NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION (6-2004)

LICENSEE EVENT REPORT (LER)

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

APPROVED BY OMB NO. 3150-0104 EXPIRES 06/30/2007

, the NRC may not conduct or sponsor, and a person is not required to respond to, the information collection.

1. FACILITY NAME Browns Ferry Unit 2

2. DOCKET NUMBER 05000260

3. PAGE 1 of 8

4. TITLE Main Steam Relief Valve Inoperability LCO Exceeded During Operating Cycles 11, 12, and 13 as a Result of Lift Setpoint Drift

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 none DOCKET NUMBER N/A 04 26 2005 2005-008-00 02 15 2007 FACILITY NAME none DOCKET NUMBER N/A

11. THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR §:(Check all that apply)

9. OPERATING MODE 1

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) 20.2203(a)(2)(i) 50.36(c)(1)(i)(A) 50.73(a)(2)(iii) 50.73(a)(2)(ix)(A) 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

10. POWER LEVEL 100 20.2203(a)(2)(vi)

X 50.73(a)(2)(i)(B) 50.73(a)(2)(v)(D) specify in Abstract below or in (If more space is required, use additional copies of (If more space is required, use additional copies of (If more space is required, use additional copies of (If more space is required, use additional copies of (If more space is required, use additional copies of (If more space is required, use additional copies of NRC Form 366A) (17)

B.

Previous LERs on Similar Events Numerous previous reports on similar events have been made from BFN and other nuclear plants. The physical phenomenon affecting MSRV lift setpoints which results in this reportable condition is well-understood, and it has been the subject of much industry study. Different mitigative approaches have been tested, but none have successfully eliminated the issue. The installation of the instrumentation logic/circuitry which will automatically open the MSRVs as appropriate during pressurization transients largely negates the conditions safety impact. This phenomenon has only a relatively small impact on the MSRV function. BFN has installed compensatory mitigation hardware. BFN is continuing to work with other industry stakeholders toward the total elimination of this issue.

C.

Additional Information

Browns Ferry corrective actions for the rework of the valves in Unit 2 Cycles 11, 12 and 13 are documented TVA corrective action documents BFPER 961764, PER 50084 and PER 81376.

The failure to report MSRV setpoint drift is documented in PER 112190.

D.

Safety System Functional Failure Consideration:

The condition being reported involves only setpoint drift of varying numbers of MSRVs on Unit 2. The safety/relief function provided by these valves was not compromised at any time. A safety system functional failure did not result from this condition.

E.

Loss of Normal Heat Removal Consideration:

The condition being reported did not involve a reactor scram.

VIII.COMMITMENTS None.