05000354/LER-2016-006

LER-2016-006,

Hope Creek Generating Station 05000354
Event date:
Report date:
Reporting criterion:	10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications
3542016006R00 - NRC Website

LER 16-006-01 for Hope Creek, Unit 1, Regarding Mode Change Without B Channel Level Instrumentation Operable

ML17124A407
Person / Time
Site:	Hope Creek
Issue date:	05/04/2017
From:	Casulli E T Public Service Enterprise Group
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
LR-N17-0084 LER 16-006-001
Download: ML17124A407 (6)

PLANT AND SYSTEM IDENTIFICATION

General Electric — Boiling Water Reactor (BWR/4) Reactor Protection System — EIIS Identifier {JC/LI}* ESF Actuation System — EIIS Identifier {JE/LI}* Containment Isolation Control System - EIIS Identifier {JM/ LI}* *Energy Industry Identification System {EIIS} codes and component function identifier codes appear as {SS/CCC}

IDENTIFICATION OF OCCURRENCE

Event Date: November 9, 2016 Discovery Date: November 9, 2016

CONDITIONS PRIOR TO OCCURRENCE

When the inoperable instrumentation was discovered, Hope Creek was in Operational Condition (OPCON) 2, Startup, with the reactor sub-critical, and a reactor startup in progress. No other structures, systems or components that could have contributed to the event were inoperable at the time of the event.

DESCRIPTION OF OCCURRENCE

During the twentieth refueling outage (H1R20) at Hope Creek, the reference leg for the B channel reactor vessel level instrumentation was replaced and rerouted using the design change process. The reference leg is normally maintained at a constant height of water by a condensing pot connected to the reactor vessel steam space. Initially, the reference leg needs to be backfilled with water to remove small pockets of air or voids which may be present. On November 9, 2018, the reference leg had not been backfified following the re-routing of the reference leg tubing, resulting in an Incorrect level indication on all B channel level Instruments.

Following replacement of the reference leg, the design change package (DCP) did not provide instructions for back-filling ° ° the reference leg. Instead, the DCP relied on the maintenance department to backfill the reference leg while returning the affected instruments to service. The maintenance supervisor was not cognizant of the DCP scope, and determined that the step to backfill the reference leg was not required. The B channel instruments were returned to service by maintenance without completing the backfill evolution. As a result, the reference leg for the B channel was not completely' filled with water, and level on this channel Indicated higher than actual level. The top of the indicating band for Technical Specification required reactor vessel instrumentation is +60 Inches, and water level was being maintained in a band of 60 to 65 inches Inches prior to making the mode change. Under this condition, all four channels of Technical Specification i required vessel level indication indicated off-scale high, above 60 inches. Vessel level was being monitored using non- ' Technical Specification required level instrumentation which has a wider Indicating range. Under this condition, the Incorrect indication on the B channel instrumentation was not observable to the plant operators.

Following the mode change, when vessel level was being lowered into the normal band of 30-39 inches, the A, C and D channels of vessel level instrumentation all tracked together into the indicating range, while the B channel remained off- ' scale high.

At approximately 0420, control room operators recognized the condition, declared the B channel inoperable and directed maintenance personnel to investigate.

I At 0528 a prompt investigation was Initiated by the Shift Manager.

Reported lessons reamed are Inc uporated Into the licensing process end fed back to industry, Send comments regarding burden estimate to the FOIA, Privacy end Informalion Collections Branch fT-5 F53), U.S. Nuclear Regulatory Commission, Washington, DC 20565-0001, cc by a-mell Infoodects.Resounoserso,gov, and to the Desk Meer, Me of information and Regulatory AIME, NEOB-10202, (3160-0104 Office of Management and Budget, Washington, DC 20503. If a means used to knpose an Information collection does not display a cu ently valid OMB =del number, the NRC may not condUcl a apnea, laid s person to not required to respond to, the Jr/Donation Wisdom Plant Technical Specifications require that all four channels of vessel level instrumentation be operable prior to making the mode change from OP CON 4, Cold Shutdown to OP CON 2, Startup. The B channel level instruments are required for the operability of the B RPS {JC} channel, the B ECCS (.1E) channels and B PCIS {JM} channels, On November 9, 2018 at 1505, the B1 RPS channel and the B Nuclear Steam Supply Shutoff System (NSSS) {JM} were placed in the tripped condition to comply with the 12 hour1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> action for Technical Specification 3.3.1, Reactor Protection System actuation instrumentation, and Technical Specification 3.3.2, Primary Containment Isolation actuation instrumentation.

Maintenance technicians completed the backfill of the B channel reference leg and the B channel was returned to operable on November 9, 2016 at 2228.

CAUSE OF EVENT

The cause of the event is personnel error. A causal evaluation is in progress. A supplement to this LER will be submitted to provide the results of the investigation.

SAFETY CONSEQUENCES AND IMPLICATIONS

There were no adverse safety consequences as a result of this event. The A, C and D channel level instruments were all operable throughout the duration of the event. The RPS system would have responded properly to shut down the reactor with the B channel level instruments inoperable. The A, C and D ECCS subsystems would have responded to an actual low level condition, and would have provided sufficient capability to restore and maintain vessel level. The reactor coolant system pressure remained within the design capability of the low pressure ECCS systems throughout the event. The PCIS system would have successfully isolated primary containment with the B channel level instruments inoperable since the A, C and D channels were operable.

The B channel level instrumentation was restored to operable prior to the mode change to Operational Condition 1, Run, which occurred on November 11, 2016 at 1423.

SAFETY SYSTEM FUNCTIONAL FAILURE

A review of this condition and the associated evaluations determined that a Safety System Functional Failure (SSFF) as I defined in Nuclear Energy Institute (NEI) 99-02, "Regulatory Assessment Performance Indicator Guideline," did not occur.

PREVIOUS EVENTS

The cause evaluation will review similarity to previous events, The result of that review will be included in the supplement

CORRECTIVE ACTIONS

1. The B channel reference leg was backfilled and returned to operable status.

2. The personnel involved in the decision to not perform the backfill were disqualified from performing similar duties.

I COMMITMENTS There are no regulatory commitments contained In this LER.