05000461/LER-1917-005, Regarding Automatic Reactor Scram During the Performance of Scram Time Testing as a Result of an Invalid Oscillating Power Range Monitor Growth Rate Trip

Regarding Automatic Reactor Scram During the Performance of Scram Time Testing as a Result of an Invalid Oscillating Power Range Monitor Growth Rate Trip

ML17212A620
Person / Time
Site:	Clinton
Issue date:	07/27/2017
From:	Stoner T Exelon Generation Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
U-604363 LER 17-005-00
Download: ML17212A620 (5)

LER-1917-005, Regarding Automatic Reactor Scram During the Performance of Scram Time Testing as a Result of an Invalid Oscillating Power Range Monitor Growth Rate Trip

Event date:
Report date:
Reporting criterion:	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)(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)(v), Loss of Safety Function 10 CFR 50.73(a)(2)(i)(A), Completion of TS Shutdown 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications 10 CFR 50.73(a)(2)(vii), Common Cause Inoperability 10 CFR 50.73(a)(2)(i)
4611917005R00 - NRC Website

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Clinton Power Station 8401 Power Road Clinton, IL 61727 U-604363 July 27, 2017 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D.C. 20555-0001

Subject:

Clinton Power Station, Unit 1 Facility Operating License No. NPF-62 NRG Docket No. 50-461 Licensee Event Report 2017-005-00 LER 2017-005-00 Exelon Generation 10CFR 50.73 SRRS 5A.108 Enclosed is Licensee Event Report (LER) 2017-005-00: Automatic Reactor Scram During the Performance of Scram Time Testing As a Result of an Invalid Oscillating Power Range Monitor Growth Rate Trip. This report is being submitted in accordance with the requirements of 10 CFR 50.73. There are no regulatory commitments contained in this report.

Should you have any questions concerning this report, please contact Mr. Dale Shelton, Regulatory Assurance Manager, at (217) 937-2800.

Respectfully,

~?\\:5 Theodore R. Stoner Site Vice President Clinton Power Station KP/bsz Attachment: Licensee Event Report 2017-005-00 cc:

Regional Administrator-NRC Region Ill NRC Senior Resident Inspector - Clinton Power Station Office of Nuclear Facility Safety - Illinois Emergency Management Agency

NRG FORM 366 (04-2017)

U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB: NO. 3150-0104 EXPIRES: 03/31/2020

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LICENSEE EVENT REPORT (LER)

(See Page 2 for required number of digits/characters for each block)

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(See NUREG-1022, R.3 for instruction and guidance for completing this form http://www.nrc.gov/reading-rm/doc-collections/nuregs/staff/sr1022/r30

1. FACILITY NAME Clinton Power Station, Unit 1

4. TITLE

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

2. DOCKET NUMBER

3. PAGE 05000461 1 OF 4 Automatic Reactor Scram During the Performance of Scram Time Testing As a Result of an Invalid Oscillating Power Range Monitor Growth Rate Trip

5. EVENT DATE MONTH DAY YEAR

6. LEA NUMBER YEAR I SEQUENTIAL I NUMBER REV NO.

05 30 2017 2017 - 005 00

7. REPORT DATE MONTH DAY YEAR 07 28 2017 FACILITY NAME FACILITY NAME

8. OTHER FACILITIES INVOLVED DOCKET NUMBER 05000 DOCKET NUMBER 05000

9. OPERATING MODE

11. THIS REPORT JS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR §: (Check all that apply)

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 (dl D 20.2203(aJ(3)(iil D 50.73(a)(2)(ii)(B)

D 50.73(a)(2)(viii)(B)

D 20.2203(a)(1 l D 20.2203(a)(4l D 5o.73(aJ(2)(iiiJ D 50.73(a)(2)(ix)(A)

D 20.2203(a)(2)(i)

D 50.36(c)(1 )(i)(A)

~ 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 73.11 (a)(4J D 20.2203(a)(2)(iiiJ D 50.36(c)(2)

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

D 73.71 (aJ(5J D 20.2203(a)(2)(iv)

D 5o.46(aJ(3J(iiJ D 50.73(a)(2)(v)(C)

D 73.77(a)(1 i 028 D 20.2203(a)(2)(v)

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

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

D 73.77(a)(2J(il D 20.2203(a)(2)(vi)

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

D 50.73(a)(2)(vii)

D 73.77(a)(2)(ii)

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

D OTHER Specify in Abstract below or in Following the automatic trip, plant systems, structures, and components responded as designed and functioned properly. There were no complications from the event.

Corrective actions were implemented to support reactor startup and completion of STT. They consisted of developing and implementing an operating and monitoring strategy when performing scram time testing in the OPRM enabled region. This included wait times after scram time testing a control rod, utilizing single notch rod withdrawal, pausing after rod withdrawal past an LRPM, additional identification of high worth control rods, and review of Average Power Range Monitor (APRM) and Local Power Range Monitor (LPRM) response. In addition, setpoints were raised for the GRA and ABA portion of the OPRMs.

The reactor was restarted on June 2, 2017 and control rod STT was completed without issue on June 4, 2017.

C. CAUSE OF EVENT

The cause of the event is under investigation and will be provided in a supplement to this event report.

D. SAFETY ANALYSIS

There were no safety consequences associated with the automatic scram. This event is reportable under the provisions of 1 O CFR 50.73(a)(2)(iv)(A) as an event or condition that resulted in a manual or automatic actuation of the reactor protection system. The condition of the reactor core at the time of the event was stable. Operator actions taken during STT and following the event were in accordance with plant procedures. Systems necessary to maintain the plant per Technical Specification requirements following the automatic plant trip performed as expected and remained available to perform their safety function.

This event report does not identify any safety system functional failures.

E. CORRECTIVE ACTIONS

Corrective actions were implemented to support reactor startup and completion of STT. These actions included:

Completed a revision to a plant procedure to establish an operating strategy when performing scram time testing in the OPRM enabled region.

YEAR 2017 SEQUENTIAL NUMBER 005 o

Implemented a monitoring strategy to assess the effectiveness of the operating strategy and monitor for expected plant response.

Raised the OPRM Amplitude and Grown Rate set points.

Additional corrective actions for this event will be provided in the follow-up LER.

F. PREVIOUS SIMILAR OCCURENCES

REV NO.

00 There are no previous similar occurrences associated with this event. CPS has not experienced a scram in the past related to the OPRM instrumentation.

G. COMPONENT FAILURE DATA

There was no component failure data associated with this event. Page_4_ of _4_