05000416/LER-2018-009-01, Reactor Manual Shutdown Due to Feedwater Level Control Changes

Reactor Manual Shutdown Due to Feedwater Level Control Changes

ML19219B109
Person / Time
Site:	Grand Gulf
Issue date:	08/07/2019
From:	Emily Larson Entergy Operations
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
GNR0-2019/00033 LER 2018-009-01
Download: ML19219B109 (5)

LER-2018-009, Reactor Manual Shutdown Due to Feedwater Level Control Changes

Event date:
Report date:
Reporting criterion:	10 CFR 50.73(a)(2)(ii)(B), Unanalyzed Condition 10 CFR 50.73(a)(2)(v), Loss of Safety Function
4162018009R01 - NRC Website

text

~~Entergy GNR0-2019/00033 August 7, 2019 U.S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555-0001

SUBJECT:

Supplemental Licensee Event Report 2018-009-01, 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 Reactor Manual Shutdown Due to Feedwater Level Control Changes Grand Gulf Nuclear Station, Unit 1 Docket No. 50-416 License No. NPF-29

Dear Sir or Madam:

Attached is Supplemental Licensee Event Report 2018-009-01 Reactor Manual Shutdown Due to Feedwater Level Control Changes. This report is being submitted in accordance with 10 CFR 50. 73(a)(2)(iv)(A) as an event or condition that resulted in an unplanned manual actuation of the reactor protection system.

This letter contains no new commitments. If you have any questions or require additional information, please contact Jim Shaw at 601-437-2103.

Sincerely, Eric A. Larson EAUrtw

Attachment:

Licensee Event Report 2018-009-01 cc: see next page

\\

v NRC Region IV-Regional Administrator NRC Senior Resident Inspector, Grand Gulf Nuclear Station NRR Project Manager

GNR0-2019/00033 Attachment Supplemental Licensee Event Report 2018-009-01

NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB: NO. 3150-0104 EXPIRES: 03/31/2020 (04-2018)

, the NRG may not conduct or sponsor, and a oerson is not required to respond to the information collection.

1. Facility Name Q. Docket Number 3.Page Grand Gulf Nuclear Station, Unit 1 05000416 1 OF3

4. Title Reactor Manual Shutdown Due to Feedwater Le~el Control Chan2:es.

5. Event Date

6. LER Number

7. Report.Date

8. Other Facilities Involved Sequential Rev Facility Name Docket Number Month Day Year Year Month Day Year N/A Number No.

05000 N/A I

09 14 2018 2018 009 01 08 07 2019 Facility Name Docket Number N/A 05000 N/A

9. Operating Mode

11. This Report is Submitted Pursuant to the Requirements of 1 O CFR §: {Check all that apply}

MODE1 D 20.2201 (b)

D 20.2203(a}(3)(i)

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

D

• 50. 73{a)(2)(viii)(A)

D 20.2201 (d)

D 20.2203(a}(3}(ii)

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

D 50. 73(a}{2}{viii)(B)

D 20.2203(a)(1)

D 20.2203(a)(4)

D 50. 73(a}{2}{iii)

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

D 20.2203(a}(2}{i) 0 50.36(c)(1 )(i)(A) 181 50. 73(a)(2)(iv)(A)

D 50. 73{a)(2)(x)

10. Power Level D 20.2203(a)(2)(ii)

D 50.36{c)(1 )(ii)(A)

D 50. 73{a)(2)(v)(A)

D 73.71 (a)(4)

• D 20.2203(a}{2)(iii)

D 50.36(c)(2)

D 50. 73(a}{2)(v)(B)

D 73.71 (a)(5) 100%

D 20.2203(a}{2)(iv)

D 50.46{a){3}{ii)

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

D 73.77(a)(1)

D 20.2203(a}{2}{v)

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}{vi)

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

D 5.0.73{a)(2)(vii)

D 73.77{~)(2)(iii)

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

D Other (Specify in Abstract below or in NR<;;

D.

CAUSE

• The cause of the manual shutdown was operator response in anticipation of reactor water level lowering to the reactor vessel water level 11.4 inch scram setpoint, caused by a reduction in feedwater system flow to the reactor vessel.

The root cause of the event was that test instructions* did not include dynamic tuning of Air Operated Valves. As a result, the heater drain tank level control system circuits were not ~dequately tuned to control level during system perturbations.

E.

CORRECTIVE ACTIONS

The following corrective actions have been completed:

Control circuits for the heater drain tank level control system have been adjusted.

The guidance in EN-DC-117, Post Modification Testing and Special Instructions, has been revised to direct that tuning is required when modifications impact control function such as: air operated valves, positioners, valve actuators, valve controllers, and other control loop components.

F.

SAFETY SIGNIFICANCE

The safety significance of this event is determined to be low. The manual scram was performed in accordance with plant procedures. There were no actual nuclear safety consequences or radiological consequences during the event.

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 2018-01-00 Reactor Manual Shutdown due to Turbine Pressure Control Valve Position Changes. The failure in that event was an incorrect setting in one element of a three element turbine control anti-resonance circuit, which is different from this event which was a control circuit tuning issue. Therefore, the corrective actions for the previous event would not have prevented this event.

. NRG FORM 3668 (02-2018)