05000416/LER-2016-006, Regarding Multiple Valid Engineered Safety Feature Actuations
| ML16242A156 | |
| Person / Time | |
|---|---|
| Site: | Grand Gulf  |
| Issue date: | 08/29/2016 |
| From: | Nadeau J Entergy Operations |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| GNRO-2016/00044 LER 16-006-00 | |
| Download: ML16242A156 (6) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(iv)(A), System Actuation 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)(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 |
| 4162016006R00 - NRC Website | |
text
~Entergy GNRO-2016/00044 August 29, 2016 U.S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555-0001 Entergy Operations, Inc.
P.o. Box756 Port Gibson, MS 39150 James Nadeau Manager, Regulatory Assurance Grand Gulf Nuclear Station Tel. (601) 437-2103
SUBJECT:
Licensee Event Report (LER) 2016-006-00, Multiple Valid Engineered Safety Feature Actuations Grand Gulf Nuclear Station, Unit 1 Docket No. 50-416 License No. NPF-29
Dear Sir or Madam:
Attached is Licensee Event Report (LER) 2016-006-00, which will be supplemented upon completion of the in-progress root cause evaluation. This report is submitted in accordance with Title 10 Code of Federal Regulations 50.73(a)(2)(iv)(A).
This letter contains no new Regulatory Commitments.
If you have any questions or require additional information, please contact James Nadeau at 601-437-2103.
Sincer;t~$~
JJN/sas Attachment: Licensee Event Report (LER) 2016-006-00 cc: (See Next Page)
GNRO-2016/00044 Page 2 of 2 cc:
U.S. Nuclear Regulatory Commission ATTN: Mr. Jim Kim, NRR/DORL (w/2)
Mail Stop OWFN 8 B1 Rockville, MD 20852-2738 U.S. Nuclear Regulatory Commission ATTN: Mr. Kriss M. Kennedy (w/2)
Regional Administrator, Region IV 1600 East Lamar Boulevard Arlington, TX 76011-4511 Mr. B. J. Smith (w/2)
Director, Division of Radiological Health Mississippi State Department of Health Division of Radiological Health 3150 Lawson Street Jackson, MS 39213 NRC Senior Resident Inspector Grand Gulf Nuclear Station Port Gibson, MS 39150
Attachment to GNRO 2016/00044 Licensee Event Report (LER) 2016-006-00
NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB: NO. 3150-0104 EXPIRES: 10/31/2018 (11-2015) the NRC may not conduct or sponsor, and a person is not required to respond to, the information collection.
- 13. PAGE Grand Gulf Nuclear Station, Unit 1 05000416 1 OF 3
- 4. TITLE Multiple Valid Engineered Safety Feature Actuations
- 5. EVENT DATE
- 6. LER NUMBER
- 7. REPORT DATE
- 8. OTHER FACILITIES INVOLVED YEAR I SEQUENTIAL I REV MONTH FACILITY NAME DOCKET NUMBER MONTH DAY YEAR NUMBER NO.
DAY YEAR N/A 05000 N/A June 30 2016 2016-006-00 08 29 2016 FACILITY NAME DOCKET NUMBER N/A 05000 N/A
- 9. OPERATING MODE
- 11. THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR §: (Check all that apply) 4 o 20.2201 (b) o 20.2203(a)(3)(i) o 50.73(a)(2)(i)(C) o 50.73(a)(2)(vii)
~l:':'
o 20.2201 (d) o 20.2203(a)(3)(ii) o 50.73(a)(2)(ii)(A) o 50.73(a)(2)(viii)(A) o 20.2203(a)(1) o 20.2203(a)(4) o 50.73(a)(2)(ii)(B) o 50.73(a)(2)(viii)(B) o 20.2203(a)(2)(i) o 50.36(c)(1 )(i)(A) o 50.73(a)(2)(iii) o 50.73(a)(2)(ix)(A)
- 10. POWER LEVEL o 20.2203(a)(2)(ii) o 50.36(c)(1 )(ii)(A)
~ 50.73(a)(2)(iv)(A) o 50.73(a)(2)(x) 0 o 20.2203(a)(2)(iii) o 50.36(c)(2) o 50.73(a)(2)(v)(A) o 73.71(a)(4) o 20.2203(a)(2)(iv) o 50.46(a)(3)(ii) o 50.73(a)(2)(v)(B) o 73.71(a)(5) o 20.2203(a)(2)(v) o 50.73(a)(2)(i)(A) o 50.73(a)(2)(v)(C) o OTHER o 20.2203(a)(2)(vi) o 50.73(a)(2)(i)(B) o 50.73(a)(2)(v)(D)
Specify in Abstract below or in =
- 2. DOCKET 05000416 YEAR I
- 3. LER NUMBER SEQUENTIAL NUMBER 2016-006-00 I
REV.
NO.
PLANT CONDITIONS PRIOR TO THE EVENT At the time of the event, Grand Gulf Nuclear Station (GGNS) Unit 1 was in Mode 4, Cold Shutdown, with Main Steam Isolation Valves (MSIVs) [SB] closed. Reactor Water Level was maintained in the normal water level band by the Control Rod Drive System (CRDS) [AA]. Residual Heat Removal (RHR) A [BO] was maintained in Shutdown Cooling operation and it was not affected by this event.
DESCRIPTION
On June 30, 2016 at 17:15, Grand Gulf Nuclear Station experienced an electrical power supply loss from Service Transformer 21 (ST21) [XFMR] which resulted in power supply being lost to Division 2 (16AB Bus) and Division 3 (17AC Bus) Engineered Safety Feature (ESF) buses [BU]. This resulted in a valid actuation of Division 2 and Division 3 Standby Diesel Generators (SDGs) [EK] on under-voltage. Both SDGs automatically started and energized their respective ESF buses as designed.
During this event, the loss of power to the Division 2 (16AB bus) resulted in a Division 2 Reactor Protection System (RPS) [JE] bus power loss, which actuated a Division 2 RPS half SCRAM signal. The Division 2 power loss also resulted in a loss of Instrument Air pressure resulting in some Control Rod Scram Valves to drift open.
This in turn caused the Scram Discharge Volume to fill to the point where a Division 1 RPS half SCRAM signal was initiated from Scram Discharge Volume level high on Channel A. This resulted in a valid full RPS Reactor SCRAM while not critical. Instrument Air pressure was restored and the SCRAM signal was reset at 1733 hrs.
Appropriate off normal event procedures were entered to mitigate the transient. No ECCS [BM] initiation signals were reached. All safety systems performed as expected.
REPORTABILITY
Event Notification 52057 was made to the NRC Operations Center. This LER is being submitted pursuant to Title 10 Code of Federal Regulations 10 CFR 50.73(a)(2)(iv)(A) for the actuation of Engineered Safety Features.
Telephonic notification was made to the U.S. Nuclear Regulatory Commission (NRC) Emergency Notification System on June 30, 2016, within 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> of the event, pursuant to 10 CFR 50.72(b)(3)(iv) for multiple valid specified system actuations.
CAUSE
Direct Cause: A faulted C phase 34.5 kV Service Transformer 21 power supply cable to the BOP 23 Transformer resulting in the loss of power to the 21R bus.
Apparent Cause: Investigation of the Apparent Cause is pngoing. A supplemental report to this LER will be provided upon completion of the Apparent Cause investigation
APPROVED BY OMB: NO. 3150-0104 EXPIRES: 10/31/2018
, the NRC may not conduct or sponsor, and a person is not required to respond to, the information NRC FORM (11-2015) 366A U.S. NUCLEAR REGULATORY COMMISSION LICENSEE EVENT REPORT (LER)
CONTINUATION SHEET collection.
- 1. FACILITY NAME Grand Gulf Nuclear Station, Unit 1 NARRATIVE
CORRECTIVE ACTIONS
- 2. DOCKET 05000416 YEAR I
- 3. LER NUMBER SEQUENTIAL NUMBER 2016-006-00 I
REV.
NO.
Temporarily installed a three phase overhead line, to bypass the faulted 34.5 kV cable section.
SAFETY SIGNIFICANCE
The event posed no threat to the health and safety of the general public or to nuclear safety as safety-systems performed as designed. No Technical Specification safety limits were violated. Industrial safety was not challenged, and there was no potential or actual radiological release during the event.
PREVIOUS SIMILAR EVENTS
Previous similar events will be discussed in the supplemental report upon completion of the Apparent Cause investigation.