05000457/LER-2007-001, Unit 2 Manual Reactor Trip Due to High Condenser Backpressure Resulting from Circulating Water Pump Trips
| ML073050330 | |
| Person / Time | |
|---|---|
| Site: | Braidwood  |
| Issue date: | 10/22/2007 |
| From: | Coutu T Exelon Generation Co, Exelon Nuclear |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| BW070082 LER 07-001-00 | |
| Download: ML073050330 (4) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 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 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications |
| 4572007001R00 - NRC Website | |
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Exelon Generation Company, LLC Braidwood Station 35100 South Route 53, Suite 84 Braceville, IL 60407-9619 www.exelOnCOTP.COM Nuclear 10 CFR 50.73 October 22, 2007 BW070082 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 Braidwood Station, Unit 2 Facility Operating License No. NPF-77 NRC Docket No. STN 50-457
Subject:
Licensee Event Report Number 2007-001 Unit 2 Manual Reactor Trip Following Circulating Water Pump Trips The enclosed Licensee Event Report (LER) is being submitted in accordance with 10 CFR 50.73,*
"Licensee event report system," paragraph (a)(2)(iv)(A). 10 CFR 50.73(a) requires an LER to be submitted within 60 days following discovery of the event, therefore, this report is being submitted by October 22, 2007.
There are no commitments contained in the attached report. Should you have any questions concerning this submittal, please contact Mr. David Gullott, Regulatory Assurance Manager, at (815) 417-2800.
Thomas Coutu Site Vice President Braidwood Station
Enclosure:
LER Number 2007-001-00 A
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NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB: NO. 3150-0104 EXPIRES: 08/31/2010 (9-2007)
, the NRC may digits/characters for each block) not conduct or sponsor, and a person is not required to respond to, the informatinn rnllnp.rtinn.
l3. PAGE Braidwood Station, Unit 2 05000457 1 OF 3
- 4. TITLE Unit 2 Manual Reactor Trip Due to High Condenser Backpressure Resulting from Circulating Water Pump Trips
- 5. EVENT DATE
- 6. LER NUMBER
- 7. REPORT DATE
- 8. OTHER FACILITIES INVOLVED I SEQUENTIAL I REV FACILITY NAME DOCKET NUMBER MONTH DAY YEAR YEAR NUMEI NO.R MONTH DAY YEAR N/A
_I I I_
FACILITY NAME DOCKET NUMBER 08 23 2007 2007 001 -
00 10 22 2007 N/A N/A
- 9. OPERATING MODE
- 11. THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR §: (Check all that apply)
[1 20.2201(b)
[I 20.2203(a)(3)(i)
[I 50.73(a)(2)(i)(C)
El 50.73(a)(2)(vii) 1 El 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)
[I 50.73(a)(2)(viii)(B)
_ 20.2203(a)(2)(i)
El 50.36(c)(1)(i)(A)
[E 50.73(a)(2)(iii)
El 50.73(a)(2)(ix)(A)
- 10. POWER LEVEL El 20.2203(a)(2)(ii)
El 50.36(c)(1)(ii)(A) 0 50.73(a)(2)(iv)(A)
[I 50.73(a)(2)(x)
[I 20.2203(a)(2)(iii)
El 50.36(c)(2)
El 50.73(a)(2)(v)(A)
El 73.71(a)(4) 100 [1 20.2203(a)(2)(iv)
[I 50.46(a)(3)(ii)
El 50.73(a)(2)(v)(B)
[1 73.71(a)(5)
[I 20.2203(a)(2)(v)
[I 50.73(a)(2)(i)(A)
El 50.73(a)(2)(v)(C)
[I OTHER [3 20.2203(a)(2)(vi)
El 50.73(a)(2)(i)(B)
El 50.73(a)(2)(v)(D)
Specify in Abstract below or in observed. The 2A level differential switch was found stuck in the closed position and replaced. This component failure did not contribute to this event. All other components and systems were found to be functioning normally and as expected.
D. Safety Consequences
There were no safety consequences impacting plant or public safety as a result of this event. All safety related systems, structures and components operated normally during this event. The loss of multiple CW pumps and the resulting high condenser backpressure are events well within the ability of the operator to control, which include the removal of Unit 2, as necessary.
During the reactor shutdown, all required safety systems responded appropriately. There was no loss of any function that would have prevented fulfillment of actions necessary to 1) Shutdown the reactor and maintain it in a safe shutdown condition, 2) Remove residual heat, 3) Control the release of radioactive material, or 4) Mitigate the consequences of an accident.
The 2A and 2B auxiliary feedwater pumps started on Low Low steam generator levels as expected. The 2C condensate / condensate booster pump automatically started on low net positive suction head, as expected.
This event did not result in a safety system functional failure.
E. Corrective Actions
The corrective action to prevent recurrence will be to install a time delay to preclude trips of the circulating water pumps due to sudden and false high differential level indication.
F. Previous Occurrences
There have been no similar Licensee Event Report events at Braidwood Station in. the last three years.
Component Failure Data
Manufacturer Nomenclature Model Mfo. Part Number N/A N/A N/A N/APRINTED ON RECYCLED PAPER NRIC FORM 366A (9-2007)
PRINTED ON RECYCLED PAPER