05000237/LER-2015-005, Regarding HPCI Motor Gear Unit Would Not Return to Full Flow During Testing
| ML15306A496 | |
| Person / Time | |
|---|---|
| Site: | Dresden  |
| Issue date: | 10/30/2015 |
| From: | Marik S Exelon Generation Co |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| 15-0063 LER 15-005-00 | |
| Download: ML15306A496 (4) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(v), Loss of Safety Function 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)(iv), System Actuation 10 CFR 50.73(a)(2)(ix) 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 |
| 2372015005R00 - NRC Website | |
text
~Exe!.on Generation Dresden Generating Station 6500 North Dresden Road Morris, IL 60450 www.exeloncorp.com 10 CFR 50.73 SVPLTR # 15-0063 October 30, 2015 U. S. Nuclear Regulatory Commission ATTrN: Document Control Desk Washington, DC 20555-0001 Dresden Nuclear Power Station, Unit 2 Renewed Facility Operating License No. DPR-19 NRC Docket No. 50-237
Subject:
Licensee Event Report 237/2015-005-00, Unit 2 HPCI Motor Gear Unit Would Not Return to Full Flow During Testing Enclosed is Licensee Event Report 237/2015-005-00, "Unit 2 HPCI Motor Gear Unit Would Not Return to Full Flow During Testing". This is an interim report which describes events which are being reported in accordance with 10 CFR 50.73(a)(2)(v)(D), "Any event or condition that could have prevented the fulfillment of the safety function of... systems that are needed to mitigate the consequences of an accident".
There are no regulatory commitments contained in this submittal.
Should you have any questions concerning this letter, please contact Mr. Bruce Franzen at (815) 416-2800.
Respectfully, Bk Shane M. Marik L.
Site Vice President Dresden Nuclear Power Station Enclosure Licensee Event Report 237/2015-005-00 cc:
Regional Administrator - NRC Region Ill NRC Senior Resident Inspector - Dresden Nuclear Power Station
NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB: NO. 3150-0104 EXPIRES: 01131/2017 (02-2014) j.,""*%Estimated burden per response to comply with this mandatory collection request: 80 hours9.259259e-4 days <br />0.0222 hours <br />1.322751e-4 weeks <br />3.044e-5 months <br />.
,*Reported lessons learned~are incorporated into the licensing process and ted back to industry.
(j,;)o Send comments regarding burden estimate to the FOIA, Privacy and Intormation Collections
~V~I'I ri~~riiintemet e-mail to Intocollects.Resource@nrc.gov. and to the Desk Otticer, Office ot Information and (See Page 2 for required number of Regulatory Affairs, NEOB-10202, (3150-0104), Offie ot Management and Budget, Washington, DC dgt/hrcesfor each block) 20503. Itsa means used to impose an information collection does not display a currently valid 0MB digis/caracerscontrol number, the NRC may not conduct or sponsor, and a person is not required to respond to, the information collection.
- 13. PAGE Dresden Nuclear Power Station, Unit 2 05000237[
1 OF 3 4,. TITLE Unit 2 HPCI Motor Gear Unit Would Not Return to Full Flow During Testing
- 5. EVENT DATE
- 6. LER NUMBER
- 7. REPORT DATE
- 8. OTHER FACILITIES INVOLVED MONT DY YEAR YEAR SEUMENILREVO MONTH DAY YEAR FACILITY NAME DOCKET NUMBER
- 9. OPERATING MODE
- 11. THIS REPORT IS SUBMITBTED PURSUANT TO THE REQUIREMENTS OF 10 CFR §: (Check all that apply)
E] 20.2201(b)
[]
20.2203(a)(3)(i)
[]
50.73(a)(2)(i)(C)
[]
50.73(a)(2)(vii)
E] 20.2201(d)
E] 20.2203(a)(3)(ii)
L] 50.73(a)(2)(ii)(A)
[]
50.73(a)(2)(viii)(A) 1 10 OWRLEE 20.2203(a)(2)(ii)
[]
50.36(c)(1)(ii)(A)
[]
50.73(a)(2)(iv)i)
D] 50.73(a)(2)(ix)(A E] 20.2203(a)(2)(iii)
E] 50.36(c)(2)
E] 50.73(a)(2)(v)(A)
[
73.71 (a)(4)
D] 20.2203(a)(2)(iv)
E] 50.46(a)(3)(ii)
[]
50.73(a)(2)(v)(B)
[]
73.71 (a)(5) 100 D] 20.2203(a)(2)(v)
E] 50.73(a)(2)(i)(A)
[]
50.73(a)(2)(v)(C)
E] OTHER D] 20.2203(a)(2)(vi)
[]
50.73(a)(2)(i)(g)
[]
50.73(a)(2)(v)(D)
Specify in Abstract below or in
______________________________________________________________________________N__C__FoNRCForm66A
- 12. LICENSEE CONTACT FOR THIS LER LICENSEE CONTACT ITELEPHONE NUMBER (Include Area Code)
Bruce Franzen - Regulatory Assurance Manager [815-416-2800AUE SYSTEM COMPONENT FACCAUSETOSYPT FACTURER TO EPIX X
BJ WlS G080 Y
P N
NT
- 14. SUPPLEMENTAL REPORT EXPECTED
- 15. EXPECTED MONH IDAY YEAR SUBMISSION
[]YES (If yes, complete 15. EXPECTED SUBMISSION DATE)
[-']NO DATE 02 9
I 16 ABSTRACT (Limit to 1400 spaces, iLe., approximately 15 single-spaced typewritten lines)
On September 23, 2015, operators were performing surveillance testing of the Unit 2 High Pressure Coolant Injection (HPCI) system. After achieving full flow, the system flow rate was lowered to 75 percent per the test procedure. System flow could not be returned to 100 percent upon subsequent adjustments. The system test was stopped and the system declared inoperable at 21:00 CDT.
The initial cause of the failure was determined to be a limit switch failure. The system was successfully tested upon component replacement.
This event is being reported under 10 CFR 50.73(a)(2)(v)(D) "Any event or condition that could have prevented the fulfillment of the safety function of... systems that are needed to mitigate the consequences of an accident."
The cause of the switch failure is under further investigation which will define safety significance and
corrective actions
NRC FORM 366 (02-2014)
PLANT AND SYSTEM IDENTIFICATION
Dresden Nuclear Power Station (DN PS), Unit 2, is a General Electric Company Boiling Water Reactor with a licensed maximum power level of 2957 megawatts thermal. The Energy Industry Identification System codes used in the text are identified as [XX].
A.
Plant Conditions Prior to Event:
Unit: 02 Reactor Mode: 1 Event Date: 09/23/15 Mode Name: Power Operation Event Time: 2100 CDT Power Level: 100 percent B.
Description of Event
On September 23, 2015, operators were performing surveillance testing of the Unit 2 High Pressure Coolant Injection (HPCI) [BJ] system. After achieving full flow, the system flow rate was lowered to 75 percent per the test procedure. System flow could not be returned to 100 percent upon subsequent adjustments. The system test was stopped and the system declared inoperable at 21:00 CDT.
The initial cause of the failure was determined to be the motor gear unit (MGU) high speed stop (HSS) limit switch failure. With the switch indicating that the MGU was at the HSS, the control system would not allow the MGU to increase speed of the HPCI turbine.
The system was successfully tested upon component replacement.
C.
Cause of Event
The cause of the switch failure is under investigation and will be documented in a supplemental report.
NRC FORM 3e6A (02-2014)
D.
Safety Analysis
With the exception of the MGU HSS limit switch failure, HPCI performed as designed and met all surveillance criteria. The system achieved full flow at the beginning of the test.
Proceduralized operator actions would have allowed the system to be returned to full flow after the failure. No loss of safety function has occurred. This event is of very low safety significance.
This event is being reported under 10 CFR 50.73(a)(2)(v)(D) "Any event or condition that could have prevented the fulfillment of the safety function of... systems that are needed to mitigate the consequences of an accident."
E.
Corrective Actions
The limit switch was replaced. Additional cycling of the MGU to determine potential binding was performed with no abnormalities noted. Corrective actions will be developed following component failure analysis and a further investigation. These results will be documented in a supplemental report.
F.
Previous Occurrences
No previous failures were identified in the initial investigation. Previous occurrences will be identified through further investigation and will be documented in a supplemental report.
G.
Component Failure Data
Manufacturer Model SIN Type General Electric CR9440K1 Ki N/A Limit Switch
PLANT AND SYSTEM IDENTIFICATION
Dresden Nuclear Power Station (DN PS), Unit 2, is a General Electric Company Boiling Water Reactor with a licensed maximum power level of 2957 megawatts thermal. The Energy Industry Identification System codes used in the text are identified as [XX].
A.
Plant Conditions Prior to Event:
Unit: 02 Reactor Mode: 1 Event Date: 09/23/15 Mode Name: Power Operation Event Time: 2100 CDT Power Level: 100 percent B.
Description of Event
On September 23, 2015, operators were performing surveillance testing of the Unit 2 High Pressure Coolant Injection (HPCI) [BJ] system. After achieving full flow, the system flow rate was lowered to 75 percent per the test procedure. System flow could not be returned to 100 percent upon subsequent adjustments. The system test was stopped and the system declared inoperable at 21:00 CDT.
The initial cause of the failure was determined to be the motor gear unit (MGU) high speed stop (HSS) limit switch failure. With the switch indicating that the MGU was at the HSS, the control system would not allow the MGU to increase speed of the HPCI turbine.
The system was successfully tested upon component replacement.
C.
Cause of Event
The cause of the switch failure is under investigation and will be documented in a supplemental report.
NRC FORM 3e6A (02-2014)
D.
Safety Analysis
With the exception of the MGU HSS limit switch failure, HPCI performed as designed and met all surveillance criteria. The system achieved full flow at the beginning of the test.
Proceduralized operator actions would have allowed the system to be returned to full flow after the failure. No loss of safety function has occurred. This event is of very low safety significance.
This event is being reported under 10 CFR 50.73(a)(2)(v)(D) "Any event or condition that could have prevented the fulfillment of the safety function of... systems that are needed to mitigate the consequences of an accident."
E.
Corrective Actions
The limit switch was replaced. Additional cycling of the MGU to determine potential binding was performed with no abnormalities noted. Corrective actions will be developed following component failure analysis and a further investigation. These results will be documented in a supplemental report.
F.
Previous Occurrences
No previous failures were identified in the initial investigation. Previous occurrences will be identified through further investigation and will be documented in a supplemental report.
G.
Component Failure Data
Manufacturer Model SIN Type General Electric CR9440K1 Ki N/A Limit Switch