05000315/LER-2012-001, Regarding Two Power Range Nuclear Instruments Inoperable Due to Common Cause
| ML12125A038 | |
| Person / Time | |
|---|---|
| Site: | Cook  |
| Issue date: | 04/13/2012 |
| From: | Gebbie J Indiana Michigan Power Co, American Electric Power |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| AEP-NRC-2012-19 LER 12-001-00 | |
| Download: ML12125A038 (6) | |
| 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 |
| 3152012001R00 - NRC Website | |
text
ONDIANA MICHIGAM AifERi A unit of American Electric Power Indiana Michigan Power One Cook Place Bridgman, MI 49106 indianaMichiganPower.com AEP-NRC-2012-19 10 CFR 50.73 April 13, 2012 Docket No. 50-315 U. S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555-0001 Donald C. Cook NuClear Plant Unit 1 LICENSEE EVENT REPORT 315/2012-001-00 TWO POWER RANGE NUCLEAR INSTRUMENTS INOPERABLE DUE TO COMMON CAUSE In accordance with the criteria established by 10 CFR 50.73, Licensee Event Report System, the following report is being submitted:
LER 315/2012-001-00: "Two Power Range Nuclear Instruments Inoperable Due To Common Cause" There are no commitments contained in this submittal.
Should you have any questions, please contact Mr. Michael K. Scarpello, Regulatory Affairs Manager, at (269) 466-2649.
Sincerely, Joel P. Gebbie Site Vice President SJM/jmr Enclosure c:
INPO Records Center J. T. King - MPSC, w/o enclosure S. M. Krawec - AEP Ft. Wayne, w/o enclosure MDEQ - WHMD/RPS, w/o enclosure NRC Resident Inspector C. D. Pederson - NRC Region III P. S. Tam - NRC Washington DC P2L
NRC Form 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB: NO. 3150-0104 EXPIRES 10/31/2013 (10-2010)
, the NRC may not conduct or sponsor, and a person is not required to respond to, the information collection.
- 3. PAGE Donald C. Cook Nuclear Plant Unit 1 05000-315 1 of 5
- 4. TITLE Two Power Range Nuclear Instruments Inoperable Due To Common Cause
- 5. EVENT DATE
- 6. LER NUMBER
- 7. REPORT DATE
- 8. OTHER FACILITIES INVOLVED SEQUENTIAL REV MONTH DAY YEAR FACILITY NAME DOCKET NUMBER NUMBER NO.
05000 FACILITY NAME DOCKET NUMBER 02 16 2012 2012 001 00 04 13 12 05000
- 9. OPERATING MODE
- 11. THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR §: (Check all that apply)
E]
20.2201(b)
El 20.2203(a)(3)(i)
El 50.73(a)(2)(i)(C) 0 50.73(a)(2)(vii)
El 20.2201(d)
El 20.2203(a)(3)(ii)
[I 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)
El 20.2203(a)(2)(i)
El 50.36(c)(1)(i)(A)
El 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)
El 50.73(a)(2)(iv)(A)
El 50.73(a)(2)(x)
El 20.2203(a)(2)(iii)
[E.
50.36(c)(2)
El 50.73(a)(2)(v)(A)
El 73.71(a)(4) 100 El 20.2203(a)(2)(iv)
El 50.46(a)(3)(ii)
El 50.73(a)(2)(v)(B) 73.71 (a)(5)
El 20.2203(a)(2)(v)
El 50.73(a)(2)(i)(A)
El 50.73(a)(2)(v)(C)
LJ OTHER Specify in Abstract below E_
20.2203(a)(2)_(vi) 50.73(a)(2)(i)(B) 50.73(a)(2)(v)(D) or in 0814 Channel 4 NI declared operable following calibration.
Upon completing the calibration of the Channel 4 NI, technicians commenced rechecking the other three NI channels' Neutron Flux High Positive Rate time constant settings to validate the as-left calibration condition in order to determine operability status. This validation was performed via partial use of an NI calibration procedure. No adjustments had been performed on the Channel 1 NI Neutron Flux High Positive Rate time constant during its calibration, so validation commenced on the Channel 2 NI Neutron Flux High Positive Rate time constant which was adjusted during calibration, as was the Channel 3 NI Neutron Flux High Positive Rate time constant.
February 17, 2012 0906 Channel 2 NI declared inoperable for calibration validation.
1005 Channel 2 NI Neutron Flux High Positive Rate time constant was validated to be out of tolerance. At this time, Operations conservatively declared the Channel 3 NI inoperable due to having been adjusted using the same recorder used to adjust the Channel 2 NI out of tolerance.
With two NI channels inoperable, Operations entered LCO 3.0.3, and calibration of the Channel 2 NI commenced.
1046 Channel 2 NI declared operable following calibration. Operations exited LCO 3.0.3 at this time with three NI channels operable.
1055 Channel 3 NI noted to remain inoperable when calibration validation commenced.
1208 Channel 3 NI Neutron Flux High Positive Rate time constant was validated to be out of tolerance and was calibrated, Channel 3 NI declared operable following calibration.
1216 Channel 1 NI declared inoperable for rate circuit time constant calibration validation.
1339 Channel 1 NI declared operable following validation that the Neutron Flux High Positive Rate time constant was within calibration tolerance. No out of calibration condition existed.
Reporting Requirements
On February 16, 2012, at 2050, the Channel 3 NI was declared inoperable to commence the Nuclear Instrumentation Power Range Channel Operational Test and Calibration. At that time, the Channel 2 NI was already inoperable due to incorrect calibration of the Neutron Flux High Positive Rate time constant; therefore, two Power Range Nuclear Instrumentation channels were inoperable at the same time. In accordance with LCO 3.0.3, action should have been initiated within 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> (by February 16, 2012, at 2150) to place the unit, as applicable, in:
a. MODE 3 within 7 hours8.101852e-5 days <br />0.00194 hours <br />1.157407e-5 weeks <br />2.6635e-6 months <br />; b.
MODE 4 within 13 hours1.50463e-4 days <br />0.00361 hours <br />2.149471e-5 weeks <br />4.9465e-6 months <br />; and c.
MODE 5 within 37 hours4.282407e-4 days <br />0.0103 hours <br />6.117725e-5 weeks <br />1.40785e-5 months <br />.
Operators had no knowledge that the Channel 2 NI had not been calibrated correctly when the Channel 3 NI was declared inoperable for calibration. As such, LCO 3.0.3 was not entered and the action time limits were therefore not met. Not meeting the action time limits is reportable in accordance with 10 CFR 50.73(a)(2)(i)(B)
"Any operation or condition which was prohibited by the plant's technical Specifications...". Further, this condition is reportable in accordance with direction provided in NUREG 1022, section 3.2.2 which states: An LER is required if a condition existed for a time longer than permitted by the technical specifications even if the condition was not discovered until after the allowable time had elapsed and the condition was rectified immediately upon discovery.
This condition is also reportable in accordance with 10 CFR 50.73(a)(2)(vii) "Any event where a single cause or condition caused at least one independent train or channel to become inoperable in multiple systems or two independent trains or channels to become inoperable in a single system..." Two channels became inoperable in a single system (Power Range Nuclear Instrumentation) as a result of the same faulty recorder being used to adjust multiple channels.
Cause of Event
A single piece of test equipment (a recorder) failed to provide accurate data during calibration of two Power Range Neutron Flux High Positive Rate time constant circuits. This caused both NI channels to be inoperable at the same time.
Analysis of Event
During the restoration portion of the calibration procedure, the Channel 4 NI was not capable of providing a valid output to the Solid State Reactor Protection System during bistable verification. At that time, the Power Range Neutron Flux High Positive Rate time constants set for Channel 2 and Channel 3 were non-conservative due to the faulty recorder. Channel 1 was the only NI channel with an operable Power Range Neutron Flux High Positive Rate trip. All other bistables on Channels 1, 2, and 3, including the High Neutron Flux trip, had been validated and were providing proper input to the Solid State Reactor Protection System prior to declaring Channel 4 inoperable for calibration.
The Power Range Neutron Flux High Positive Rate trip provides a trip signal during rod ejection accidents. The reactor protection modeled in the safety analysis for a rod ejection accident is only the High Neutron Flux trip.
Because the High Neutron Flux trip was not affected, 3 of 4 Power Range channels were capable of providing the 2 of 4 logic required to fulfill their required safety functions during the channel calibrations.
The event does not constitute a degraded or unanalyzed condition because the reactor protection modeled in the safety analysis is the Power Range Neutron Flux High trip which remained available as described above.
As such, Power Range NI Channels 1, 2, and 3 were capable of providing the High Neutron Flux trip.
Corrective Actions
Completed Corrective Actions Power Range NI channels' rate circuits were calibrated to within the required tolerance using a replacement recorder.
Planned Corrective Actions
Revise the Power Range NI Channel Operational Test and Calibration procedures as follows:
Add guidance to provide a peer check of the rate circuit time constant checks and, before making any adjustments, to verify with other test equipment if an out of tolerance condition is identified with the time constant.
Create a Pre Job Brief database entry to address the lessons learned from this calibration evolution.
Communicate lessons learned and extent of cause to promote critical analysis of small deviations from expected performance and maintaining a strong questioning attitude.
Review other Reactor Protection surveillance procedures that use the same brand of recorder, and initiate actions as needed to incorporate cautionary steps based on the lessons learned from this event.
Previous Similar Events
LERs for both CNP Unit 1 and Unit 2 for the past three years were reviewed for similar events related to 10 CFR 50.73(a)(2)(i)(B) and 10 CFR 50.73(a)(2)(vii) reporting criteria. The following were identified:
315-2010-001-00 lAB EDG Fuel Oil Transfer Pumps Inoperable With one EDG Fuel Oil Transfer Pump out of service for power cable replacement, the power cable for the remaining Fuel Oil Transfer Pump was cut inadvertently resulting in no AB Fuel Oil Transfer Pumps being operable. This is reportable in accordance with 10 CFR 50.73(a)(2)(i)(B) 316-2010-002-00 Containment Divider Barrier Seal Mounting Bolts Not Properly Installed Containment divider barrier bolts were identified to be missing or loose during inspection taking place during an outage. This is reportable in accordance with 10 CFR. 50.73(a)(2)(i)(B) 316-2010-003-00 Changed Modes from Mode 5 to Mode 4 with Divider Barrier Inoperable Operators determined that the containment divider barrier was inoperable approximately 5 hours5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br /> after the unit ascended from Mode 5 to Mode 4. The seal had recently been reassembled, but the assembly was not properly verified prior to mode change. This is reportable in accordance with 10 CFR 50.73(a)(2)(i)(B)