05000331/LER-2014-005, Regarding Automatic Start of Standby Diesel Generators Due to Grid Disturbance
| ML14246A207 | |
| Person / Time | |
|---|---|
| Site: | Duane Arnold  |
| Issue date: | 08/29/2014 |
| From: | Vehec T NextEra Energy Duane Arnold |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| NG-14-0206 LER 14-005-00 | |
| Download: ML14246A207 (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 10 CFR 50.73(a)(2)(iv), System Actuation |
| 3312014005R00 - NRC Website | |
text
NEXTera" ENERC August 29, 2014 NG-14-0206 10 CFR 50.73 U.S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, D.C. 20555-0001 Duane Arnold Energy Center Docket 50-331 Renewed Op. License No. DPR-49 Licensee Event Report #2014-005 Please find attached the subject report submitted in accordance with 10 CFR 50.73. This letter makes no new commitments or changes to any existing
commitments
T. A. Vehec Vice President, Duane Arnold Energy Center NextEra Energy Duane Arnold, LLC cc:
Administrator, Region Ill, USNRC Project Manager, DAEC, USNRC Resident Inspector, DAEC, USNRC NextEra Energy Duane Arnold, LLC, 3277 DAEC Road, Palo, IA 52324
NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB: NO. 3150-0104 EXPIRES: 01131/2017 (02-2014)
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 TREPORT (LER)
Branch (T-5 F53), U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001, or by LICENSEE EVENT internet e-mail to Infocollects.Resource@nrc.gov, and to the Desk Officer, Office of Information and (See Page 2 for required number of 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 digits/characters for each block) control number, the NRC may not conduct or sponsor, and a person is not required to respond to, the information collection.
- 3. PAGE Duane Arnold Energy Center 05000-331 1 OF 3
- 4. TITLE Automatic Start of Standby Diesel Generators due to Grid Disturbance
- 5. EVENT DATE
- 6. LER NUMBER
- 7. REPORT DATE
- 8. OTHER FACILITIES INVOLVED MOT A
ERiFACILITY NAME DOCKET NUMBER MONTH DAY YEAR YEAR SEQUENTIAL REV MONTH DAY YEAR NA NUMBER NO.
N/A N/A FACILITY NAME DOCKET NUMBER 06 30 2014 2014 -
005
- - 00 08 29 2014 N/A N/A
- 9. OPERATING MODE
- 11. THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR §: (Check all that apply)
[L 20.2201(b)
LI 20.2203(a)(3)(i)
[I 50.73(a)(2)(i)(C)
LI 50.73(a)(2)(vii)
[_i 20.2201(d)
LI 20.2203(a)(3)(ii)
[L 50.73(a)(2)(ii)(A)
L] 50.73(a)(2)(viii)(A)
Li 20.2203(a)(1)
LI 20.2203(a)(4)
[i 50.73(a)(2)(ii)(B)
LI 50.73(a)(2)(viii)(B)
_L 20.2203(a)(2)(i)
LI 50.36(c)(1)(i)(A)
LI 50.73(a)(2)(iii)
LI 50.73(a)(2)(ix)(A)
- 10. POWER LEVEL LI 20.2203(a)(2)(ii)
EL 50.36(c)(1)(ii)(A)
Z 50.73(a)(2)(iv)(A)
I]
50.73(a)(2)(x)
LI 20.2203(a)(2)(iii)
L] 50.36(c)(2)
LI 50.73(a)(2)(v)(A)
EL 73.71(a)(4)
LI 20.2203(a)(2)(iv)
[]
50.46(a)(3)(ii)
LI 50.73(a)(2)(v)(B)
El 73.71(a)(5) 98%
LI 20.2203(a)(2)(v)
LI 50.73(a)(2)(i)(A)
LI 50.73(a)(2)(v)(C)
L] 50.73(a)(2)(i)(B)
Sl 50.73(a)(2)(v)(D) specify in Abstract below or in
I.
Description of Event
On June 30, 2014, at 1913, while operating at 98% power, a grid disturbance resulted in an automatic start of both of the site's Emergency Diesel Generators (EDGs) (lEE Code EK). Neither EDG loaded onto its respective essential bus. The cause of the EDG starts was a momentary (approximately 13 cycles) dip in essential bus voltage to 62%. A review of the system design showed that since the EDGs started on an automatic start signal of essential bus voltage less than 65% for greater than 12 cycles, the EDGs operated as designed. Both EDGs were secured and returned to their normal standby readiness condition at 2116 on June 30, 2014.
There were no radiological releases associated with this event. There were no other structures, systems or components inoperable at the start of this event that contributed to the event.
II.
Assessment of Safety Consequences
The automatic starting of the EDGs in response to a short-duration under voltage condition had no personnel or radiological safety significance. Since the diesel generators were capable of fulfilling their safety function throughout this, there is no nuclear safety significance.
This event resulted in an 8 hour9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> reportable event. The Resident Inspector was notified, and Event Notification 50246 was made pursuant to 10 CFR 50.72(b)(3)(iv)(A) due to a valid system actuation.
This event did not result in a safety system functional failure. There were no automatically or manually initiated safety system responses.
II1.
Cause of Event
An Apparent Cause Evaluation was completed. The cause of the EDG starts was a momentary (approximately 13 cycles) dip in essential bus voltage to 62%. A review of the system design showed that since the EDGs started on an automatic start signal of essential bus voltage less than 65% for greater than 12 cycles, the EDGs operated as designed.
IV.
Corrective Actions
Both EDGs were secured and returned to their normal standby readiness condition at 2116 on June 30, 2014.
V.
Additional Information
Previous Similar Occurrences:
A review of DAEC Licensee Event Reports from the past 5 years identified one previous similar occurrence. LER 2010-001 documented an automatic start of the "A" EDG on a valid undervoltage condition; the EDG did not load to its respective essential bus.
EIIS System and ComDonent Codes:
EK - Emergency Onsite Power Supply System Reportingq Requirements:
This event is being reported due to a valid system actuation, 10CFR50.73(a)(2)(iv).