05000461/LER-2013-001, Inadequate Risk Identification Results in Loss of Safety Function

Inadequate Risk Identification Results in Loss of Safety Function

ML13122A260
Person / Time
Site:	Clinton
Issue date:	04/17/2013
From:	Noll W Exelon Generation Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
U-604116 LER 13-001-00
Download: ML13122A260 (5)

LER-2013-001, Inadequate Risk Identification Results in Loss of Safety Function

Event date:
Report date:
Reporting criterion:	10 CFR 50.73(a)(2)(i) 10 CFR 50.73(a)(2)(vii), Common Cause Inoperability 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)(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
LER closed by
IR 05000461/2013005 (11 February 2014)
4612013001R00 - NRC Website

text

wExelon Generation.

Clinton Power Station 8401 Power Road Clinton, IL 61727 U-604116 April 17, 2013 10 CFR 50.73 SRRS 5A.108 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D. C. 20555-0001 Clinton Power Station, Unit 1 Facility Operating License No. NPF-62 NRC Docket No. 50-461

Subject:

Licensee Event Report 2013-001-00 Enclosed is Licensee Event Report (LER) No. 2013-001-00: Inadequate Risk Identification Results in Loss of Safety Function. 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 Ms. Kathy Ann Baker, Regulatory Assurance Manager, at (217)-937-2800.

Respt l William G. Noll Site Vice President Clinton Power Station RSF/blf

Enclosures:

Licensee Event Report 2013-001-00 cc:

Regional Administrator - NRC Region III NRC Senior Resident Inspector - Clinton Power Station Office of Nuclear Facility Safety - IEMA Division of Nuclear Safety o~jl

NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB: NO. 3150-0104 EXPIRES: 10/31/2013 (10-2010)

, the NRC may sfor each block) not conduct or sponsor, and a person is not required to respond to, the digits/characters finformation collection.

13. PAGE Clinton Power Station, Unit 1 05000461 1 OF 4

4. TITLE Inadequate Risk Identification Results in Loss of Safety Function

5. EVENT DATE

6. LER NUMBER

7. REPORT DATE

8. OTHER FACILITIES INVOLVED SEQUENTIAL FACILITY NAME DOCKET NUMBER MONTH DAY YEAR YEAR NUMBER N

EANO. MONTH DAY YEAR 05000 FACILITY NAME DOCKET NUMBER 02 18 2013 2013 001 00 04 17 2013 05000

9. OPERATING MODE

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

El 20.2201(b)

El 20.2203(a)(3)(i)

El 50.73(a)(2)(i)(C)

El 50.73(a)(2)(vii) 1 El 20.2201(d)

El 20.2203(a)(3)(ii)

-] 50.73(a)(2)(ii)(A)

El 50.73(a)(2)(viii)(A) 0l 20.2203(a)(1)

El 20.2203(a)(4)

[I 50.73(a)(2)(ii)(B)

El 50.73(a)(2)(viii)(B)

[E 20.2203(a)(2)(i)

[I 50.36(c)(1)(i)(A)

El 50.73(a)(2)(iii)

[I 50.73(a)(2)(ix)(A)

10. POWER LEVEL El 20.2203(a)(2)(ii) 0l 50.36(c)(1)(ii)(A)

[J 50.73(a)(2)(iv)(A)

El 50.73(a)(2)(x)

El 20.2203(a)(2)(iii)

[I 50.36(c)(2)

[I 50.73(a)(2)(v)(A)

E] 73.71(a)(4) 090 El 20.2203(a)(2)(iv)

[I 50.46(a)(3)(ii)

El 50.73(a)(2)(v)(B)

E] 73.71 (a)(5)

[I 20.2203(a)(2)(v) 0l 50.73(a)(2)(i)(A)

[] 50.73(a)(2)(v)(C)

El OTHER El 20.2203(a)(2)(vi)

[E 50.73(a)(2)(i)(B)

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

Specify in Abstract below or in Since HPCS was declared inoperable and is a single train safety system, this event was determined to be reportable under the provisions of 10 CFR 50.73(a)(2)(v)(D), as a condition that could have prevented fulfillment of the HPCS safety function which is needed to mitigate the consequences of an accident. At 1035 hours0.012 days <br />0.288 hours <br />0.00171 weeks <br />3.938175e-4 months <br />, the station notified the NRC of this event via Emergency Notification 48765. Issue Report 1476647 was initiated to investigate this event.

C. CAUSE OF EVENT

The cause of this event was an inadequate risk identification related to pendulum motion of the cable connector during jobsite planning and set up for the job. The technicians and FLS had identified the shorting risk of the fuse block in panel [PL] 1H13-P672 and installed a robust operational barrier to mitigate the identified risk. The planning did not identify the vulnerability of contact that could happen due to a pendulum motion of a dropped cable connector.

D. SAFETY CONSEQUENCES

There were no safety consequences as a result of this event. This event resulted in the transfer of the Division 4 Nuclear System Protection System (NSPS) Bus to its alternate source, causing the Division 4 NSPS Inverter to be inoperable and thus causing the HPCS to be inoperable. There was no loss of power and HPCS remained functional and available, but inoperable. At 0925 hours0.0107 days <br />0.257 hours <br />0.00153 weeks <br />3.519625e-4 months <br /> on 02/18/13, the NSPS bus was transferred without incident from its alternate power source back to the Division 4 NSPS Inverter, and HPCS was declared operable.

A complete loss of power to Division 4 NSPS during a loss of off-site power will not prevent HPCS from performing its safety function. NSPS design is such that HPCS initiation logic and its associated process inputs located in Division 3 of NSPS can function independent of Division 4 NSPS circuitry to support the HPCS function. At the time of this event, Division 3 NSPS was available, operable and fully capable of initiating HPCS.

Updated Safety Analysis Report Section 8.3.2.1.1 states, "The system [Class 1E 125 Volts DC Power System] design allows for the single failure or loss of any redundant [DC] subsystem during simultaneous accident and loss of offsite power conditions without adversely affecting safe shutdown of the plant. Only Division 1, Division 2, and Division 3 [Volts DC] subsystems are required to be considered for safe shutdown analysis of the plant."

E.

CORRECTIVE ACTIONS

Immediate corrective action included a stand-down with Instrument Maintenance personnel to discuss the event and lessons learned. Instrument Maintenance technicians were required to attend the stand-down prior to returning to work.

Additional corrective action for this event includes requiring Maintenance Front Line Supervisors (FLS) and Group Leads to use a checklist designed to aid in challenging jobsite conditions for risk/hazards assessment for a period of time, and having the Maintenance department managers conduct paired observations of the use of the checklist with the FLS and Group Leads. Additionally, a case study will be performed with the Instrument, Electrical, and Mechanical Maintenance Departments using this event to highlight determining risk perception and robust barriers.

F. PREVIOUS OCCURRENCES

A review for previous occurrences did not identify similar events at Clinton Power Station.

G. COMPONENT FAILURE DATA

Not Applicable