05000389/LER-1917-002, Regarding 2A3 4.16 Kv Bus De-Energization Due to Voltage Meter Failure
| ML17195A184 | |
| Person / Time | |
|---|---|
| Site: | Saint Lucie  |
| Issue date: | 07/14/2017 |
| From: | Deboer D Florida Power & Light Co |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| L-2017-126 LER 17-002-00 | |
| Download: ML17195A184 (4) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 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)(v), Loss of Safety Function 10 CFR 50.73(a)(2)(i)(A), Completion of TS Shutdown 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications 10 CFR 50.73(a)(2)(vii), Common Cause Inoperability 10 CFR 50.73(a)(2)(i) |
| 3891917002R00 - NRC Website | |
text
I= PL..
U. S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, D.C. 20555 Re:
St. Lucie Unit 2 Docket No. 50-389 Reportable Event: 2017-002-00 Date of Event: May 15, 2017 JUL t: 4 2017'-
2A3 4.16 KV Bus De-Energization Due to Voltage Meter Failure L-2017-126 10 CFR 50.73 Licensee Event Report 2017-002-00 is being submitted pursuant to the requirements of 10 CFR 50.73 to provide notification of the subject event.
Respectfully, Daniel DeBoer Site Director St. Lucie Plant DD/I<:\\X'F Attachment cc:
USNRC Regional Administrator, Region II USNRC Senior Resident Inspector, St. Lucie Nuclear Plant Florida Power & Light Company 6501 S. Ocean Drive, Jensen Beach, FL 34957
NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION (06-2016)
LICENSEE EVENT REPORT (LER)
(See Page 2 for required number of digits/characters for each block)
APPROVED BY OMB: NO. 3150-0104 EXPIRES: 10/31/2018 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 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 St. Lucie Unit 2
- 2. DOCKET NUMBER 05000389
- 3. PAGE 1 Of 3
- 4. TITLE 2A3 4.16 KV Bus De-Energization Due to Voltage Meter Failure
- 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 5
15 2017 2017 002 0
07 14 2017 FACILITY NAME DOCKET NUMBER 05000
- 9. OPERATING MODE
- 11. THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR §: (Check all that apply) 1 20.2201(b) 20.2203(a)(3)(i) 50.73(a)(2)(ii)(A) 50.73(a)(2)(viii)(A) 20.2201(d) 20.2203(a)(3)(ii) 50.73(a)(2)(ii)(B) 50.73(a)(2)(viii)(B) 20.2203(a)(1) 20.2203(a)(4) 50.73(a)(2)(iii) 50.73(a)(2)(ix)(A) 20.2203(a)(2)(i) 50.36(c)(1)(i)(A) 50.73(a)(2)(iv)(A) 50.73(a)(2)(x)
- 10. POWER LEVEL 20.2203(a)(2)(ii) 50.36(c)(1)(ii)(A) 50.73(a)(2)(v)(A) 73.71(a)(4) 100 20.2203(a)(2)(iii) 50.36(c)(2) 50.73(a)(2)(v)(B) 73.71(a)(5) 20.2203(a)(2)(iv) 50.46(a)(3)(ii) 50.73(a)(2)(v)(C) 73.77(a)(1) 20.2203(a)(2)(v) 50.73(a)(2)(i)(A) 50.73(a)(2)(v)(D) 73.77(a)(2)(i) 20.2203(a)(2)(vi) 50.73(a)(2)(i)(B) 50.73(a)(2)(vii) 73.77(a)(2)(ii) 50.73(a)(2)(i)(C)
OTHER Specify in Abstract below or in Page 3 of 3 protective function (e.g., blown PT fuses resulting in the de-energization of its associated bus UV relays). These reviews also identified several metering circuits that were not fuse protected; however, in these cases any proposed meter failure would only annunciate with no corresponding automatic protective function.
Safety Significance
The 2A EDG received a start signal from the under voltage condition on the 2A3 bus, but did not start as the EDG had been properly removed from service for preplanned maintenance. Upon a loss of indicated power to the potential transformers, the 2A3 4.16 KV bus responded appropriately for the existing plant conditions (e.g.,
the under voltage circuit relays actuated, the incoming breaker to the 4.16 KV bus opened, and a start signal was provided to the associated 2A EDG which was properly removed from service). Although the safety related 2A3 loads were lost during this event, the redundant loads serviced by the 2B3 train 4.16 KV safety related electrical bus remained unaffected by the event and the unit remained at 100% power.
Normal power was restored to the 2A3 4.16KV bus within 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> of the event, well within the allowable 8-hour Technical Specification action statement for restoring the 2A3 4.16 KV bus. Therefore, this event had no significant impact on the health and safety of the public.
The Unit 2 UFSAR section 8.3 describes Failure Modes and Effects for the 4.16 KV safety related system. This analysis bounds the observation of the event described in this LER.
Corrective Actions
- 1. As an interim corrective action until action 4 below is completed, caution tags were placed on the Unit 2 EDG voltmeter selector switches directing that the switches not be left in the 1-3 position.
- 2. The local voltmeter for the 2A EDG was replaced.
The following corrective action is being managed under the Corrective Action Program:
- 3. The local voltmeter for the 2B EDG will be replaced.
- 4. FPL is developing a modification to the 2A and 2B EDG metering circuit to install coordinated fuses between the metering circuit and the PT fuses to isolate the metering circuit from the UV relays in the event of a voltmeter fault.
Failed Components Identified General Electric AB40 voltmeters
Additional Information
None