05000254/LER-2018-004, For Quad Cities Nuclear Power Station, Unit 1, Reactor Scram Due to Turbine-Generator Load Reject

For Quad Cities Nuclear Power Station, Unit 1, Reactor Scram Due to Turbine-Generator Load Reject

ML18325A067
Person / Time
Site:	Quad Cities
Issue date:	11/21/2018
From:	Ohr K Exelon Generation Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
SVP-18-083 LER 2018-004-00
Download: ML18325A067 (4)

LER-2018-004, For Quad Cities Nuclear Power Station, Unit 1, Reactor Scram Due to Turbine-Generator Load Reject

Event date:
Report date:
Reporting criterion:	10 CFR 50.73(a)(2)(iv)(A), System Actuation 10 CFR 50.73(a)(2)(ii)(A), Seriously Degraded 10 CFR 50.73(a)(2)(ii)(B), Unanalyzed Condition 10 CFR 50.73(a)(2) 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 10 CFR 50.73(a)(2)(vii), Common Cause Inoperability 10 CFR 50.73(a)(2)(i)
2542018004R00 - NRC Website

text

=~Exelon Generation SVP-18-083 November 21, 2018 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D.C. 20555 Quad Cities Nuclear Power Station, Unit 1 Renewed Facility Operating License No. DPR-29 NRC Docket No. 50-254 10 CFR 50.73

Subject:

Licensee Event Report 254/2018-004-00 "Reactor Scram Due to Turbine-Generator Load Reject".

Enclosed is Licensee Event Report (LER) 254/2018-004-00, "Reactor Scram Due to Turbine-Generator Load Reject", for Quad Cities Nuclear Power Station, Unit 1.

This report is submitted in accordance with 1 O CFR 50.73(a)(2)(iv)(A) for an event or condition that resulted in manual or automatic actuation of any of the systems listed in paragraph (a)(2)(iv)(B).

There are no regulatory commitments contained in this letter.

Should you have any questions concerning this report, please contact Mark Humphrey at (309) 227-2800.

/4 Kenneth S. Ohr Site Vice President Quad Cities Nuclear Power Station cc:

Regional Administrator - NRC Region Ill NRC Senior Resident Inspector - Quad Cities Nuclear Power Station

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

""'***"'i' person is not required to respond to, the infoonation collection.

3. Page Quad Cities Nuclear Power Station Unit 1 05000254 1

OF 3

4. Title Reactor Scram Due to Turbine-Generator Load Reject

5. Event Date

6. LER Number

7. Report Date

8. Other Facilities Involved I

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

Month Day Year 05000 Facility Name Docket Number 09 26 2018 2018 -

004 00 11 21 2018 05000

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)(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) 1 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)

D 50.36(c)(1 )(i}(A) r8J 50.73(a)(2)(iv)(A)

D 50.73(a)(2)(x) 1 O. 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) 100 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 The Root Cause identified for this event was inadequate enforcement of Technical Human Performance (THU) and pre-job briefing standards resulting in the inability of the Operating Crew to identify error precursors and adequately challenge all participants' understanding of the purpose and expected results of the contact status checks.

D. SAFETY ANALYSIS

System Design

The Quad Cities' switchyard is configured in a ring bus to ensure that during full-power operation, when one of the 345 KV breakers or one of the 345 KV transmission lines is removed from service, at least one of the two ring bus unit output breakers remains closed. Having both ring bus unit output breakers open at the same time would result in both breakers' load reject contacts being made up, which by design causes a load-reject trip of the Turbine-Generator and a subsequent Automatic Reactor SCRAM.

Safety Impact The safety significance of this event was minimal. All systems responded as designed during the event. Operators performed required actions safely and in accordance with procedures and training.

Risk Insights A risk assessment of the turbine-generator trip was performed for this event. The resulting assessment concluded that the event was not risk significant since Conditional Core Damage Probability (CCDP) and Conditional Large Early Release Probability (CLERP) were below the threshold.

E. CORRECTIVE ACTIONS

Immediate Corrective Actions:

The governing procedures were revised to incorporate enhanced guidance for performing contact checks on unit output breakers to support Unit 1 startup.

Follow-up Corrective Actions:

1.

Operations Dept. to develop plan to re-enforce THU use within operating crews.

2.

Maintenance Dept. to develop plan to re-enforce technical fundamentals within maintenance crews.

F. PREVIOUS OCCURRENCES

No previous similar events have occurred at the site based on a search of station LERs and !Rs.

G. COMPONENT FAILURE DATA

No component failures were associated with this event. An ICES entry was completed for the event. Page_3_ of i