ML18088B198

LER 2018-001-00 for Grand Gulf Nuclear Station, Unit 1, Reactor Manual Shutdown Due to Turbine Pressure Control Valve Position Changes

ML18088B198
Person / Time
Site:
Issue date:	03/29/2018
From:	Larson E A Entergy Operations
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
GNRO-2018/00010 LER 2018-001-00
Download: ML18088B198 (6)

Text

• *~=':r* Entergy GNR0-2018/00010 March 29, 2018 U.S. Nu9lear Regulatory Commission Attn: Document Control Desk Washington, DC 20555-0001 Entergy Operations, Inc. P. 0. Box756 Port Gibson, MS 39150 Eric A. Larson Site Vice President Grand Gulf Nuclear Station Tel. (601) 437-7500 10CFR50.73

SUBJECT:

Licensee Event Report 2018-001-00, Reactor.Manual Shutdown due to Turbine Pressure Control Valve Position Changes Grand Gulf Nuclear Station, Unit 1 Docket No. 50-416 License No. NPF-29

Dear Sir or Madam:

Attached is Licensee Event Report 2018-001-00, Reactor Manual Shutdown due to Turbine Pressure Control Valve Changes.

This report is being submitted in accordance with 1 OCFR50. 73(a)(2)(iv)(A) for any event or condition that resulted in a manual or automatic actuation of any of the systems listed in 1 OCFR50.73(a)(2)(iv)(B).

This letter contains no new commitments.

If you have any questions or require additional information, please contact Dougla$ Neve at 601-437-2103.

' Sincerely, rct_ Eric A. Larson Site Vice President Grand Gulf Nuclear Station *EAUdre

Attachment:

Licensee Event Report 2018-001-00 cc: see next page GNR0-2018/00010 Page 2 of 2 U.S. Nuclear Regulatory Commission A TIN: Mr. Siva Ling am* Mail Stop OWFN 8 81 Rockville, MD 20852-2738

.NRC Senior Resident Inspector Grand Gulf Nuclear Station Port Gibson, MS 39150 U. S. Nuclear Regulatory Commission ATTN: Mr. Kriss Kennedy, NRR/DORL (w/2) Mail Stop OWFN 8 81 Washington, DC 20555-0001 r

GNR0-2018/00010 Attachment Licensee Event Report 2018-001-00 NRC FORM 366 U.S; NUCLEAR REGULATORY COMMISSION APPROVED.

BY OMB: NO. 3150-0104 EXPIRES:

10/31/2018 (06-2016)

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 />. . ':J>fl. REOl.f( Reported lessons learned are incorporated into the licensing process and fed back to industry.

~c:, ""'>-LICENSEE EVENT REPORT Send comments regarding burden estimate to the FOIA, Privacy and Information Collections o~ (LER) Branch (T-5 F53), U.S. Nuclear.Regulatory Commission, Washington, DC 20555-0001, or by e-mail ff/ " to lnfocollects.Resource@nrc.gov, and to the Desk Officer, Office of Information and Regulatory

!; t; : (See reverse for required.

number of 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 ~4-.., ~Q.f? digits/characters for each block) number, the NRC may not conduct or sponsor, and a person is not required to respond to, the **** .... information collection.

1. FACILITY NAME 2. DOCKET NUMBER 13. PAGE Grand Gulf Nuclear Station, Unit 1 05000 416 1 OF3 4. TITLE Reactor Manual Shutdown due to Turbine Pressure Control Valve Position Changes 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 01 30 2018 2018-001-00 03 29 2018 N/A 05000 N/A 9. OPERATING MODE 11. THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR §: (Check all that apply) D 20.2201(b)

D 20.2203(a)(3)(ii)

D 50.73(a)(2)(ii)(B)

D 50.73(a)(2)(ix)(A)

MODE1 D 20.2201(d)

D 20.2203(a)(4)

D so.73(a)(2)(iii)

• D 50.73(a)(2)(x)

D 20.2203(a:)(1)

D 50.36(c)(1

)(i)(A) 50.73(a)(2)(iv)(A)

D 73.71 (a)(4) D 20.2203(a)(2)(i)

D 50.36(c)(1

)(ii)(A)

D 50.73(a)(2)(v)(A)

D 73.71 (a)(s) 10. POWER LEVEL D 20.2203(a)(2)(ii)

D so.36(c)(2)

D 50.73(a)(2)(v)(B)

D 73.77(a)(1)

D 20.2203(a)(2)(iii)

D so.46(a)(3)(ii)

D 50.73(a)(2)(v)(G)

D 73. 77(a)(2)(i) 91% D 20.2203(a)(2)(iv)

D 50.73(a)(2)(i)(A)

D 50.73(a)(2)(v)(D)

D 73. 77(a)(2)(ii)

D 20.2203(a)(2)(v)

D 50.73(a)(2)(i)(B)

D 50.73(a)(2)(vii)

D OTHER D 20.2203(a)(2)(vi)

D 50.73(a)(2)(i)(C)

D 50.73(a)(2)(viii)(A)

Specify in Abstract below D 20.2203(a)(3)(i)

D 50.73(a)(2)(ii)(A)

D 50.73(a)(2)(viii)(B) or in NRC Form 366A 12. LICENSEE CONTACT FOR THIS LER FACILITY NAME I TELEPHONE NUMBER {Include Area Code) Douglas Neve I Manager, Regulatory Assurance (601) 437*2103

13. COMPLETE ONE LINE FOR EACH COMPONENT FAILURE DESCRIBED IN THIS REPORT CAUSE SYSTEM COMPONENT MANU-REPORTABLE CAUSE SYSTEM COMPONENT MANU-REPORTABLE FACTURER TO EPIX FACTURER TO EPIX 1H13P825 B H13 JC05 Siemens Yes N/A N/A N/A N/A N/A C332 i 14. SUPPLEMENTAL REPORT EXPECTED 15.EXPECTED MONTH DAY YEAR O YES (If yes, complete

15. EXPECTED SUBMISSION DA TE) SUBMISSION N/A N/A N/A ~NO DATE ABSTRACT (Limit to 1400 spaces, i.e., approximately 15 single-spaced typewritten lines) On January 30, 2018, Grand Gulf Nuclear Station (GGNS) was operating in Mode 1 at 91 % power and was in the process of. increasing power. At 1739 hours0.0201 days <br />0.483 hours <br />0.00288 weeks <br />6.616895e-4 months <br /> CST on January 30, 2018, GGNS experienced main turbine control valve (TCV) position changes of between 3 and 5 percent and main generator output load cha.nges of approximately 20 megawatts with a periodicity of approximately 3 seconds.

At 1822 on January 30, 2018, operators performed a manual shut down of the reactor by moving the reactor mode switch from RUN to SHUTDOWN to place the unit in Mode 3. Upon reactor shutdown all systems performed as designed and no subsequent safety system actuations occurred.

The cause of the manual shutdown was conservative operator response to unanticipated main turbine generator output changes.

Corrective actions include adjustments to the control circuit, and revision of work task documents for adjustment of the control circuits.

There wer~ no consequences to the general safety. of the public, nuclear safety, industriai safety and radiological safety for this event. Page 1 of3 NRC FORM (6~2016) 366A U;S. NUCLEAR REGULA TORY COMMISSION APPROVED BY OMB: NO. 3150-0104 EXPIRES:

10/31/2018 LICENSEE EVENT R.EPORT (LER) CONTINUATION SHEET l;stimated 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 mail to lnfocollects.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 NAM!; 2. DOCKET Grand Gulf Nuclear Station, Unit 1 05000 416 NARRATIVE A. . PLANT CONDITIONS PRIOR TO THE EVENT YEAR I 3. LER N,UMBER SEQUENTIAL NUMBER 2018-001-00 I :Grand*Gulf-Nuclear-Station

{GGNS) *Unit *1-was operating at-91% power in Mode-1 and *increasing power. There were no Structures,

Systems, or Components that were inoperable that contributed to the event. B. DESCRIPTION REV. NO. At 1739 hours0.0201 days <br />0.483 hours <br />0.00288 weeks <br />6.616895e-4 months <br /> CST on January 30, 2018, while the plant was operating at approximately 91 % reactor power/1322 megawatts electric power (mwe), operators observed a 20 mwe electrical oscillation

• (peak-to

• peak) with-a *peri9dicity of-approximately 3 *seconds.

Concurrent

• oscillations of *between 3 and 5% were noted on all four turbine control valves. At 1822 hours0.0211 days <br />0.506 hours <br />0.00301 weeks <br />6.93271e-4 months <br /> on January 30, 2018, operators performed a manual shutdown of the reactor by moving the reactor mode switch from RUN to SHUTDOWN.

Upon reactor shutdown all systems performed as designed and no subsequent safety system actuations occurred:

C. REPORTABILITY This report is made pursuant to 10CFR50.73(a)(2)(iv)(A) for any event or condition that resulted in a manual or automatic actuation of any of the systems listed in 1 OCFR50. 73(a)(2)(iv)(B).

This event was reported under 10CFR50.72(b)(3)(iv)(B)(1) in ENS notification 53115. D. CAUSE The cause of the reactor scram was a manual shutdown of the reactor due to operator concerns about main generator output variations, caused by unanticipated turbine pressure control valve (TCV) motion. The t~rbine pressure control system controls turbine speed, operates the steam bypass system to keep reactor pressure within limits and avoid transients, and controls main turbine inlet pressure.

The unanticipated TCV motion was caused by an incorrect setting in one element of a three element turbine control anti-resonance circuit.

The incorrect setting did not create an error of such magnitude as to *be automatically excluded from the circu*irinternal diagnostics,

• but did create enough compensatory response from the TCV to be discernable by the operating crew. The cause evaluation is in progress and the licensee event report will be updated if any substantive changes in the cause or corrective actions.

Page 2of 3

. { NRC FORM (6-2016) 366A U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB: NO. 3150-0104 EXPIRES:

10/31/2018 LICENSEE EVENT REPORT (LEA) CONTINUATION SHEET Estimated burden per response to comply with this mc:indatory 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 mail to lnfocollects.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 NRG may not conduct or sponsor, and a person is not required to respond to, the information collection

.. 1. FACILITY NAME 2. DOCKET Grand Gulf Nuclear Station, Unit 1 05000 416 E. CORRECTIVE ACTIONS The following corrective actions are completed or planned.

Completed:

YEAR 3. LEA NUMBER SEQUENTIAL NUMBER 2018-001-00

• Control circuit card has been replaced and adjusted to correct tolerances and retested satisfactorily.

REV. NO. Planned actions included in the corrective action program which may be changed in accordance with the program:

• Revise procedure to set up TCV circuitry to reflect appropriate test report F. SAFETY SIGNIFICANCE The safety significance of this event is low because all systems operated as designed and the TCV changes did not challenge any safety parameters.

The manual scram was performed as a conservative measure.

There were no actual nuclear safety consequences or radiological consequences during the eve~t. G. PREVIOUS SIMILAR EVENTS Entergy conducted a three-year review of the relevant licensee event reports and determined that there was one similar known event reported as GGNS Licensee Event Report 2016-05-00 "Automatic Reactor SCRAM." The failure in that event was a failed amplifier card, which is different from this event which is an incorrect potentiometer setting.

Therefore, the corrective actions for the previous event would not have prevented this event. Page 3 of3