05000461/LER-2018-005, Unplanned Reactor Scram During Maintenance Outage Due to High Intermediate Range Monitor Flux

Unplanned Reactor Scram During Maintenance Outage Due to High Intermediate Range Monitor Flux

ML18361A567
Person / Time
Site:	Clinton
Issue date:	12/21/2018
From:	Stoner T Exelon Generation Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
SRRS 5A.108, U-604460 LER 2018-005-00
Download: ML18361A567 (4)

LER-2018-005, Unplanned Reactor Scram During Maintenance Outage Due to High Intermediate Range Monitor Flux

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)(iii) 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)(i)
4612018005R00 - NRC Website

text

Clinton Power Station 8401 Power Road Clinton, IL 61727 U-604460 December 21, 2018 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 NRC Docket No. 50-461 Licensee Event Report 2018-005-00 Exelon Generation 10 CFR 50.73 SRRS 5A.108 Enclosed is Licensee Event Report (LER) 2018-005-00: Unplanned Reactor Scram During Maintenance Outage Due to High Intermediate Range Monitor Flux. 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,

~~

Theodore R. Stoner Site Vice President Clinton Power Station KP/lam Attachment: Licensee Event Report 2018-005-00 cc:

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

Illinois Emergency Management Agency

NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY 0MB: NO. 3150-0104 EXPIRES: 03/31/2020 (04-2018)

, the NRC may not conduct or sponsor, and a person is not required to respond to, the infonnation collection.

3.Page Clinton Power Station, Unit 1 05000461 1

OF 3

4. Title Unplanned Reactor Scram During Maintenance Outage Due to High Intermediate 'Range Monitor Flux

5. Event Date

6. LER Number

7. Report Date

8. Other Facilities Involved I

Sequ_ential I Rev Facility Name Docket Number Month Day Year Year Number No.

Month Day Year osoo'o Facility Name Docket Number 10 28 2018 2018 -

005 00 12 21 2018 05000

9. Operating Mode

11. This Report is Submitted Pursuant to the Requirements of 1 O 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(d)

D 20.2203(a)(3)(ii)

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

D 50.73(a)(2)(viii)(B) 3 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) o. 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 73.71 (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)

D 20.2203(a)(2)(iv)

D 50.46(a)(3)(ii)

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

D 73.77(a)(1) 001 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)(i)

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 C.

Cause of the Event

The root cause of this event is currently under investigation. The causal factors that resulted in this condition and the associated corrective actions will be provided in a revision to this Licensee Event Report (LER).

D.

Safety Consequences

This event is reportable in accordance with 1 O CFR 50.73(a)(2)(iv)(A) as "any event or condition that resulted in the manual or automatic actuation of the Reactor Protection System."

00 The scram caused by increased flux to the IRMs involved no safety consequences or failures of plant equipment. The condition of the reactor core at the time of the event was stable. 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.

E.

Corrective Actions

Following the reactor scram, Procedure 3006.01, Unit Shutdown, was revised to include Appendix F, Plant Shutdown Briefing Topics, specific to performance of a soft shutdown. The procedure revision indicates that soft shutdowns are prohibited until further notice and it prohibits forced cool down until all control rods are fully inserted.

Additional corrective actions will be provided in a supplemental LER.

F.

Previous Similar Occurrences There were no previous events identified involving a low power RPS actuation similar to the occurrence described in this licensee event report.

G.

Component Failure Data

There were no failed components associated with this event. Page _3_ of _3_