05000416/LER-2016-004, Regarding Automatic Reactor Scram During Turbine Stop and Control Valve Surveillance
| ML16225A724 | |
| Person / Time | |
|---|---|
| Site: | Grand Gulf  |
| Issue date: | 08/12/2016 |
| From: | Nadeau J Entergy Operations |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| GNRO-2016/00045 LER 16-004-00 | |
| Download: ML16225A724 (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 |
| 4162016004R00 - NRC Website | |
text
..
=.yEnlergy GNRO-2016/00045 August 12, 2016 U.S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555-0001 Entergy Operations, Inc.
P. O. Box 756 Port Gibson, MS 39150 James Nadeau Manager, Regulatory Assurance Grand Gulf Nuclear Station Tel. (601) 437-2103
SUBJECT:
Dear Sir or Madam:
Licensee Event Report (LER) 2016-004-00, Automatic Reactor SCRAM during Turbine Stop and Control Valve Surveillance Grand Gulf Nuclear Station, Unit 1 Docket No. 50-416 License No. NPF-29 Attached is Licensee Event Report (LER) 2016-004-00, 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 commitments. Should you have any questions or require additional information, please contact James Nadeau at (601) 437-2103.
Sincerely, JJN/tmmr/(/th Attachment: Licensee Event Report (LER) 2016-004-00 cc: (See Next Page)
GNRO-2016/00045 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: Kriss M. Kennedy (w/2)
Regional Administrator, Region IV 1600 East Lamar Boulevard Arlington, TX 76011-4511 NRC Senior Resident Inspector Grand Gulf Nuclear Station Port Gibson, MS 39150
Attachment to GNRO-2016/00045 Licensee Event Report (LER) 2016-004-00
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 05000 416 1 OF 3
- 4. TITLE Automatic Reactor SCRAM during Turbine Stop and Control Valve Surveillance
- 5. EVENT DATE
- 6. LER NUMBER
- 7. REPORT DATE
- 8. OTHER FACILITIES INVOLVED YEAR I SEQUENTIAL I REV FACILITY NAME DOCKET NUMBER MONTH DAY YEAR NUMBER NO.
MONTH DAY YEAR N/A 05000 N/A FACILITY NAME DOCKET NUMBER 06 17 2016 2016 - 004 - 00 08 12 2016 N/A 05000 N/A
- 9. OPERATING MODE
- 11. THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR §: (Check all that apply) 1 o 20.2201 (b) o 20.2203(a)(3)(i) o 50.73(a)(2)(i)(C) o 50.73(a)(2)(vii) 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) 65 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 2016-004-00 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 1 at approximately 65%
rated thermal power due to a planned power reduction to complete a Control Rod sequence exchange, Steam Jet Air Ejector (SJAE) swap, Cooling Tower acid flush, and Main Turbine Stop and Control Valve Operability Surveillance. All systems, structures and components that were necessary to mitigate the consequences of, or limit the safety implications of an event were available. No safety significant components were out of service.
DESCRIPTION
On June 17, 2016, GGNS was in Mode 1 at approximately 65%
rater thermal power performing the Main Turbine Stop and Control Valve Operability Surveillance. During the surveillance, the 'B' Turbine Stop Valve was closed, as directed by the surveillance procedure. While the 'B' Turbine Stop Valve was closed, the '0' Turbine Stop Valve unexpectedly closed, resulting in a Division II Reactor Protection System (RPS) half SCRAM signal.
With the 'B' and '0' Turbine Stop Valves closed, the remaining 'A' and 'C' Turbine Control Valves were challenged to precisely control Turbine and Reactor pressure. This resulted in Reactor pressure and power oscillations. Although oscillations were occurring, Reactor pressure and water level maintained margin to SCRAM setpoints.
Multiple attempts were made to reset the 'B' Turbine Stop Valve followed by power reduction. While driving rods to reduce power, the Reactor received an automatic SCRAM at 0257 on a Neutron Monitoring System Oscillation Power Range Monitoring (OPRM) trip.
REPORTABIL1TY This Licensee Event Report (LER) is being submitted pursuant to Title 10 Code of Federal Regulations (10 CFR) 50.73(a)(2)(iv)(A) for an automatic actuation of the RPS.
Telephonic notification was made to the U.S. Nuclear Regulatory Commission (NRC)
Emergency Notification System on June 17, 2016, within 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> of the event pursuant to 10 CFR 50.72(b)(2)(iv)(B) and 10 CFR 50.72 (b)(3)(iv)(A) for a valid RPS actuation while the reactor was critical.
NRC FORM (11-2015) 366A U.S. NUCLEAR REGULATORY COMMISSION LICENSEE EVENT REPORT (LER)
CONTINUATION SHEET APPROVED BY OMB: NO. 3150-0104 EXPIRES: 10/3112018
, the NRC may not conduct or sponsor, and a person is not required to respond to, the information collection.
- 1. FACILITY NAME Grand Gulf Nuclear Station, Unit 1 NARRATIVE
CAUSE
- 2. DOCKET 05000416 YEAR I
- 3. LER NUMBER SEQUENTIAL NUMBER 2016-004-00 I
REV.
NO.
Direct Cause: The reset solenoid valve 1N32F514C initiated the event due to a malfunction after it was actuated per the surveillance procedure. The actuation of this reset solenoid valve triggered the loss of trip fluid pressure, and subsequent closure of the 'D' stop valve. During initial investigation, the solenoid valve was found to have remained in the tripped position during the surveillance which allowed the trip header pressure to be inappropriately vented.
Root Cause: Investigation of the root cause is ongoing. A supplemental report to this LER will be provided upon completion of the root cause investigation.
CORRECTIVE ACTIONS
The immediate corrective action was to replace both the 1N32F514C and 1N32F515C solenoid valves.
SAFETY SIGNIFICANCE
The event posed no threat to the health and safety of the general public or to nuclear safety as RPS 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 root cause investigation.