05000263/LER-2015-002, From Monticello Nuclear Generating Plant Regarding Loss of Shutdown Cooling Due to Improperly Landed Jumper Wire
| ML15180A322 | |
| Person / Time | |
|---|---|
| Site: | Monticello  |
| Issue date: | 06/29/2015 |
| From: | Gardner P Northern States Power Co, Xcel Energy |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| L-MT-15-033 LER 2015-002-00 | |
| Download: ML15180A322 (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 |
| 2632015002R00 - NRC Website | |
text
(l Xcel Energy*
June 29, 2015 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 Monticello Nuclear Generating Plant Docket 50-263 Renewed Facility Operating License No. DPR-22 Monticello Nuclear Generating Plant 2807 W County Road 75 Monticello, MN 55362 L-MT-15-033 10 CFR 50.73 LER 2015-002-00 "Loss of Shutdown Cooling Due to Improperly Landed Jumper Wire" Enclosed, is the Monticello Nuclear Generating Plant (MNGP) Licensee Event Report (LER) 2015-002-00 regarding a loss of shutdown cooling. This condition is reportable to the NRC in accordance with 10 CFR 50. 73(a)(2)(v)(B), as an Event or Condition that Could have Prevented the Fulfillment of the Safety Function of Structures or Systems that are Needed to Remove Residual Heat.
Summary of Commitments no new commitments and no revisions to existing commitments.
t, Monticello Nuclear Generating Plant Northern States Power Company-Minnesota Enclosure cc:
Regional Administrator, Region Ill, USNRC Project Manager, MNGP, USNRC Resident Inspector, MNGP, USNRC
NRC FORM 366 (02-2014)
NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION (02-2014)
LICENSEE EVENT REPORT (LER)
(See Page 2 for required number of digits/characters for each block)
APPROVED BY OMB: NO. 3150-0104 EXPIRES: 01/31/2017 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 fed back to industry.
Send comments regarding burden estimate to the FOIA, Privacy and Information Collections Branch (T-5 F53), U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001, or by internet e-mail to Infocollects.Resource@nrc.gov, and to the Desk Officer, Office of Information and Regulatory Affairs, NEOB-10202, (3150-0104), Office of Management and Budget, Washington, DC 20503. If a means used to impose an information collection does not display a currently valid OMB control number, the NRC may not conduct or sponsor, and a person is not required to respond to, the information collection.
- 1. FACILITY NAME Monticello Nuclear Generating Plant
- 2. DOCKET NUMBER 05000-263
- 3. PAGE 1 OF 3
- 4. TITLE Loss of Shutdown Cooling Due to Improperly Landed Jumper Wire
- 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 DOCKET NUMBER 05000 05 02 2015 2015 -
002
- - 00 06 29 2015 FACILITY NAME DOCKET NUMBER 05000
- 9. OPERATING MODE
- 11. THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR §: (Check all that apply) 5 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)
- 10. POWER LEVEL 20.2203(a)(2)(ii) 50.36(c)(1)(ii)(A) 50.73(a)(2)(iv)(A) 50.73(a)(2)(x) 0%
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 20.2203(a)(2)(vi) 50.73(a)(2)(i)(B) 50.73(a)(2)(v)(D)
Specify in Abstract below or in LICENSEE EVENT REPORT (LER)
CONTINUATION SHEET The event was determined to be reportable in accordance with 10 CFR 50.73(a)(2)(v)(B) as an Event or Condition that Could have Prevented the Fulfillment of the Safety Function of Structures or Systems that are Needed to Remove Residual Heat. This event is considered a Safety System Functional Failure per NEI 99-02 Revision 7.
SAFETY SIGNIFICANCE
With the unit in Mode 5, the RHR SDC System is not required to mitigate any events or accidents evaluated in the safety analyses. The RHR SDC System is required for removing decay heat to maintain the temperature of the reactor coolant.
Residual heat removal was supported by a single FPCC pump and reactor coolant temperature was maintained less than the 125 degrees F required for maintaining safe shutdown of the plant. Heat up calculations were performed and determined RPV maximum coolant temperatures would remain less than 115 degrees F after 55 hours6.365741e-4 days <br />0.0153 hours <br />9.093915e-5 weeks <br />2.09275e-5 months <br /> while the single FPCC Pump provided decay heat removal. The safety significance of this event was minimal and there were no consequences that affected public health and safety.
CAUSE
Direct cause was determined shortly after the event occurred. During surveillances that were performed on Bus-15 relays, a technician improperly landed a jumper wire across the incorrect terminals and caused a no voltage signal to trip the breaker. The direct cause of the human performance error was inadequate use of concurrent verification techniques. The physical environment created an error precursor as the terminal strip was located in a tight space that complicated the concurrent verification process. The verifier failed to recognize the performer miscounted down the terminal strip to the inappropriate terminal. This Licensee Event Report (LER) will be supplemented upon completion of a root cause evaluation.
CORRECTIVE ACTION
Immediate corrective actions included suspension of all work pending approval of the shift manager to ensure outage activities did not further degrade plant conditions and electrical work was limited to protect SDC. SDC was restored by cross tying LC-103 to LC-104 using approved plant procedures.
This LER will be supplemented upon completion of a root cause evaluation to include all corrective actions implemented to preclude reoccurrence of this event.
PREVIOUS SIMILAR EVENTS
There was one previous similar event in the past three years captured in LER 2013-004, Loss of Normal Off-Site Power as a Result of Switchgear Fault, where shutdown cooling was lost. This event was not caused by a human performance error; therefore corrective actions as a result of this event would not have prevented loss of shutdown cooling reported in this LER.
ADDITIONAL INORMATION The Institute of Electrical and Electronics Engineer codes for equipment are denoted by [XX].