05000387/LER-2006-006, Regarding Automatic Scram Due to Main Generator Lockout
| ML070370109 | |
| Person / Time | |
|---|---|
| Site: | Susquehanna  |
| Issue date: | 01/24/2007 |
| From: | Saccone R Susquehanna |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| PLA-6151 LER 06-006-00 | |
| Download: ML070370109 (4) | |
| 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 |
| 3872006006R00 - NRC Website | |
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R. A. Saccone Vice President - Nuclear Operations PPL Susquehanna, LLC 769 Salem Boulevard Berwick, PA 18603 Tel. 570.542.3959 Fax 570.542-1504 rasaccone@pplweb.com SI vmp~mm -:.
p TM JAN 24 2007 U. S. Nuclear Regulatory Commission Attn: Document Control Desk Mail Stop OP 1-17 Washington, DC 20555 SUSQUEHANNA STEAM ELECTRIC STATION LICENSEE EVENT REPORT 50-387/2006-006-00 PLA-6151 Docket 50-387 Attached is Licensee Event Report 50-387/2006-006-00. This event was determined to be reportable per 10 CFR 50.73(a)(2)(iv)(A) for an unplanned actuation of systems used to mitigate the consequences of significant events. On November 25, 2006, Susquehanna Unit 1 automatically scrammed in response to a generator lockout which was caused by a loss of generator field.
There were no actual consequences to the health and safety of the public as a result of this event.
No new regulatory commitments have been created through issuance of this report.
Robert A. Saccone Vice President - Nuclear Operations Attachment cc:
Mr. C. R. Welch, NRC Sr. Resident Inspector Mr. S. J. Collins, NRC Regional Administrator, Region I Mr. R. R. Janati, DEP/BRP Mr. R. Osborne, Allegheny Electric 2I~z
NRC FORM 366 U.S. NUCLEAR REGULATORY APPROVED BYOMB: NO. 3150-0104 EXPIRES: 06/30/2007 (6-2004)
, the NRC may not conduct or sponsor, and a person is not required to respond to, the information collection.
- 1. FACILITY NAME Susquehanna Steam Electric Station - Unit 1
- 2. DOCKET NUMBER
- 3. PAGE 05000387 1 OF3
- 4. TITLE Automatic Scram due to Main Generator Lockout
- 5. EVENT DATE
- 6. LER NUMBER
- 7. REPORT DATE
- 8. OTHER FACILITIES INVOLVED MONTH DAY YEAR YEAR SEQUENTIAL REV MONTH DAY YEAR FACILITY NAME DOCKET NUMBER NUMBER NO.
05000 FACILITY NAME DOCKET NUMBER 11 25 2006 2006 006 00 1
24 2007 05000
- 9. OPERATING MODE
- 11. THIS REPORT IS SUBMITFED PURSUANT TO THE REQUIREMENTS OF 10 CFR §: (Check all that apply) 1 El 20.2201 (b)
El 20.2203(a)(3)(i)
El 50.73(a)(2)(i)(C)
[I 50.73(a)(2)(vii)
- 10. POWER LEVEL [E 20.2201(d)
El 20.2203(a)(3)(ii)
El 50.73(a)(2)(ii)(A)
El 50.73(a)(2)(viii)(A)
El 20.2203(a)(1)
El 20.2203(a)(4)
El 50.73(a)(2)(ii)(B)
El 50.73(a)(2)(viii)(B) 100%
[1 20.2203(a)(2)(i)
[I 50.36(c)(1)(i)(A)
El 50.73(a)(2)(iii)
El 50.73(a)(2)(ix)(A)
[I 20.2203(a)(2)(ii)
E] 50.36(c)(1)(ii)(A)
Z 50.73(a)(2)(iv)(A)
[I 50.73(a)(2)(x)
El 20.2203(a)(2)(iii)
[] 50.36(c)(2)
El 50.73(a)(2)(v)(A)
El 73.71 (a)(4)
El 20.2203(a)(2)(iv)
El 50.46(a)(3)(ii)
El 50.73(a)(2)(v)(B)
[] 73.71 (a)(5)
[I 20.2203(a)(2)(v)
[E 50.73(a)(2)(i)(A)
[E 50.73(a)(2)(v)(C)
[E OTHER Voluntary Report El 20.2203(a)(2)(vi)
[E 50.73(a)(2)(i)(B)
[E 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 NRC Form 366A)
ANALYSIS / SAFETY SIGNIFICANCE Actual Consequences:
On November 25, 2006, a grid disturbance led to a loss of field event on the Unit 1 Main Generator. The loss of the Unit 1 Main Generator field led to actuation of the Unit 1 bus lockout relays, a Unit 1 Main Turbine trip, and a Unit 1 Reactor Scram.
All safety systems operated as expected. The reactor reached Operating Mode 3 in a stable condition.
Potential Consequences:
Challenges to nuclear safety can result from equipment failure or human errors during recovery of the reactor to normal shutdown conditions. The potential consequence results in a negligible increase in the probabilistic risk to the health and safety of the public.
CORRECTIVE ACTIONS
The followingq corrective actions have been completed:
Temporary monitoring equipment was installed on both the Unit 1 and Unit 2 auto voltage regulators.
Main Generator stability tuning and minimum excitation limit adjustments were completed.
Until planned corrective actions are sufficiently completed, the Unit 1 Main Generator Voltage Regulator is being maintained in manual to ensure continued station operation during grid disturbances.
The following corrective actions are planned:
Training and/or processes will be developed and implemented to ensure appropriate PPL Susquehanna, LLC personnel understand generator control and protection schemes.
Appropriate active / reactive current compensator (ARCC) setting changes will be established and implemented.
General Electric Technical Information Letter 961-3 will be re-evaluated and implemented as appropriate.
(Full or partial implementation of TIL 961-3 may enhance the unit's ability to respond correctly to grid disturbances.)
ADDITIONAL INFORMATION
Failed Components Information:
None Past Similar Events:
Docket No. 50-388 LER 2005-005-00 and LER 2005-005-01