05000296/LER-2005-002, Reactor Scram from Main Turbine Trip on Low Condenser Vacuum

Reactor Scram from Main Turbine Trip on Low Condenser Vacuum

ML053190382
Person / Time
Site:	Browns Ferry  (DPR-068)
Issue date:	11/10/2005
From:	O'Grady B Tennessee Valley Authority
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
LER 05-002-00
Download: ML053190382 (9)

LER-2005-002, Reactor Scram from Main Turbine Trip on Low Condenser Vacuum

Event date:
Report date:
Reporting criterion:	10 CFR 50.73(a)(2)(iv)(A), System Actuation 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)(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 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications
2962005002R00 - NRC Website

text

November 10, 2005 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 3 - DOCKET 50-296 - FACILITY OPERATING LICENSE DPR LICENSEE EVENT REPORT (LER) 50-296/2005-002-00 The enclosed report provides details of an automatic scram which occurred on Unit 3. During the performance of a maintenance activity on a secondary plant feedwater heater level control valve, an air in-leakage path to the main condenser developed such that condenser vacuum decreased to the main turbine trip point. This trip then occurred in accordance with the plant design, and, also in accordance with the plant design, the turbine trip from greater than 30% power directly resulted in a reactor scram.

In accordance with 10 CFR 50.73(a)(2)(iv)(A), TVA is reporting this event as the valid actuation of the reactor protection system and of containment isolation valves in more than one system. 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 November 10, 2005 Enclosure cc (Enclosure):

(Via NRC Electronic Distribution)

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

One White Flint, North 11555 Rockville Pike Rockville, Maryland 20852-2739 Mr. Stephen J. Cahill, 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 November 10, 2005 WDC:DTL:PSH:BAB Enclosure cc (Enclosure):

B. M. Aukland, POB 2C-BFN A. S. Bhatnagar, LP 6A-C J. C. Fornicola, LP 6A-C N. M. Moon, BR 4T-C R. F. Marks, PAB 1C-BFN G. W. Morris, BR 4X-C R. G. Jones, NAB 1A-BFN J. R. Rupert, NAB 1A-BFN K. W. Singer, LP 6A-C E. J. Vigluicci, ET 11A-K NSRB Support, LP 5M-C INPO:LEREvents@inpo.org EDMS WT CA - K

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 3

2. DOCKET NUMBER 05000296

3. PAGE 1 OF 6

4. TITLE Reactor Scram from Main Turbine Trip on Low Condenser Vacuum

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 9

17 2005 2005-002-00 11 10 2005 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)

X 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 73 20.2203(a)(2)(vi) 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 NRC Form 366A) (17) VI. CORRECTIVE ACTIONS A.

Immediate Corrective Actions

The alarm response procedures for Unit 2 and for Unit 3 on low condenser vacuum were revised to highlight the difference between control room indication and automatic trip actuation.

B.

Corrective Actions to Prevent Recurrence(1)

1. Training will be provided to all managers and supervisors to improve effective operational decision making.

2. Improvements will be made in the Unit 2 and Unit 3 loss of condenser vacuum abnormal operating procedures.

VII. ADDITIONAL INFORMATION

A.

Failed Components high pressure feedwater heater level control valve 3-LCV-006-0073A (Fisher Controls)

B.

Previous LERs on Similar Events None C.

Additional Information

Browns Ferry corrective action document PER 89506 D.

Safety System Functional Failure Consideration:

This event does not involve a safety system functional failure which would be reported in accordance with NEI 99-02. The scram was caused by the response of non-safety related equipment to balance-of-plant conditions. All safety-related equipment performed in accordance with design in response to the event.

E.

Loss of Normal Heat Removal Consideration:

The main condenser vacuum was sufficient with ample margin to allow the condenser to continue as the heat sink during this event, and the condensate/feedwater systems continued to provide reactor vessel inventory make-up. Neither HPCI nor RCIC operated during this event. This event does not constitute a scram with a loss of normal heat removal which would be reported in accordance with NEI 99-02.

VIII. COMMITMENTS

None (1) TVA does not consider these corrective actions to be regulatory commitments. The completion of these actions will be tracked in TVAs Corrective Action Program.