05000461/LER-2017-006

LER-2017-006, 1 OF 3

Clinton Power Station, Unit 1
Event date:	06-02-2017
Report date:	08-01-2017
Reporting criterion:	10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications
4612017006R00 - NRC Website

LER 17-006-00 for Clinton, Unit 1 re Secondary Containment Inoperable During Mode Change Due to Doors Propped Open

ML17215A233
Person / Time
Site:	Clinton
Issue date:	08/01/2017
From:	Stoner T R Exelon Generation Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
SRRS 5A.108, U-604364 LER 17-006-00
Download: ML17215A233 (4)

comments regarding burden estimate to the Information Services Branch (T-2 F43), U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001, or by e-mail to Infocollects.ResourceD'.nrc.gov, and to the Desk Officer, Office of Information and Regulatory Affairs, NEOB-10202. (3150-0104), Office of Management and Budget, Washington, DC 20503. If a means used to impose an information collection does not display a currently valid OMB control number, the NRC may not conduct or sponsor, and a person is not required to respond to, the information collection.

3. LER NUMBER 1. FACILITY NAME

PLANT AND SYSTEM IDENTIFICATION

General Electric—Boiling Water Reactor, 3473 Megawatts Thermal Rated Core Power Energy Industry Identification System (EIIS) codes are identified in the text as [XX]

EVENT IDENTIFICATION

Secondary Containment Inoperable During Mode Change A. Plant Operating Conditions before the Event Unit: 1 Mode: 2 Event Date: June 2, 2017 Event Time: 0241 Mode Name: Power Operation Reactor Power: 000 percent . DESCRIPTION OF EVENT On June 2, 2017, while the plant was in Mode 4, maintenance personnel were performing welding activities associated with the 'B' Reactor Water Cleanup System (RT) [CE] pump. In support of these activities, an Operations Work Control Supervisor (WCS) provided authorization to prop open both RT 'B' pump room doors (a Secondary Containment (SC) boundary) to allow welding cables to extend through the doors. The authorization was granted, however, without utilizing the plant barrier impairment process (PBI) per plant procedures. This process provides guidance on actions necessary to evaluate and compensate for an impaired barrier. As the plant prepared for startup and the transition to operating Mode 2 commenced, Operations personnel made a plant announcement requiring that primary and secondary containment be established. The announcement was not heard by personnel working on the `B' RT pump. The plant entered Mode 2 at 0241. The doors were found propped open at 0300 shortly after the plant entered Mode 2 by Operations shift personnel. Technical Specification (TS) 3.6.4.1, Secondary Containment, actions were then entered to restore SC. Both 'B' RT doors were later closed and SC was restored twenty four minutes following discovery of the open RT doors.

comments regarding burden estimate to the Information Services Branch (.1-2 F43), U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001, or by e-mail to Infccollects.Rescurce@nrc.gov, and to the Desk Officer, Office of Information and Regulator; Affairs, ; used to impose an information collection does not display a currently valid OMB control number, the NRC may not conduct or sponsor, and a person is not required to respond to, the information , collection.

2017 006 - 00

C. CAUSE OF EVENT

The cause of the event was that the PEI process was not followed per plant procedures.

Maintenance personnel did not follow the PE3I process by asking the WCS if a PI3I was needed and the WCS was focused on restoration of RT Pump 'B' and failed to consider the need to review the PI3I procedure and allowed the work to be performed without a PBI.

D. SAFETY ANALYSIS

There were no safety consequences associated with inoperability of SC as described in this report.

Secondary Containment differential pressure remained negative throughout this event.

The SC vacuum is kept slightly negative relative to the atmospheric pressure to prevent leakage to the atmosphere. The Standby Gas Treatment (VG) [BFI] is the safety-related system which is relied upon to perform this function following an accident. During the event the VG system was available during this event. The open RT 'B' doors were later closed and TS actions were subsequently exited.

Therefore, the ability of the station to maintain secondary containment in an accident scenario was never jeopardized or challenged by the loss of secondary containment.

This event is reportable under the provisions of 10 CFR 50.73(a)(2)(i)(B) as operation prohibited by Technical Specifications.

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

E. CORRECTIVE ACTIONS

Corrective actions planned or taken following the event included implementing the management action response checklist (MARC) principles for the responsible supervisor and conducting a read and sign of the Pf3I procedure and its interaction with the work process for schedulers and planners.

F. PREVIOUS SIMILAR OCCURENCES

This are no previous similar occurrences involving a mode change with an inoperable secondary containment.

G. COMPONENT FAILURE DATA

There was no component failure data associated with this event.