05000321/LER-2016-001

LER-2016-001, Performance of Fuel Movement with Inoperable Rod Position Indication System in Violation of Technical Specifications

Edwin I. Hatch Nuclear Plant Unit 1
Event date:	02-11-2016
Report date:	04-08-2016
Reporting criterion:	10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications
3212016001R00 - NRC Website

LER 16-001-00 for Edwin I. Hatch, Unit 1, Regarding Performance of Fuel Movement With Inoperable Rod Position Indication System in Violation of Technical Specifications

ML16099A342
Person / Time
Site:	Hatch
Issue date:	04/08/2016
From:	Pierce C R Southern Co, Southern Nuclear Operating Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
NL-16-0471 LER 16-001-00
Download: ML16099A342 (6)

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PLANT AND SYSTEM IDENTIFICATION

General Electric- Boiling Water Reactor (BWR) Energy Industry Identification System codes appear in the text as (EIIS Code XX)

DESCRIPTION OF EVENT

On 02/11/16, during the Hatch 1R27 outage, fuel movement activities were halted, due to a faulty grapple camera. Once the camera was fixed, the fuel movement activities recommenced. After a couple of minutes, the operator was unable to lower a blade guide into the core. It was discovered that a refueling interlock of the main grapple was encountered. This had occurred because 20 Rod Position Indication System (RPIS) Position Indicating Probes (PIPs) had been disconnected. The work to remove the PIPs was authorized by the Work Release Supervisor and the Unit 1 Shift Supervisor, out of sequence.

The RPIS indications were bypassed and the blade guide was lowered into the core followed by continuing fuel movement.

After a review of Technical Specification 3.9.4, Control Rod Position Indication, it was determined that fuel movement should not be performed with the RPIS probe disconnected and bypassed because the associated control rods were not hydraulically disarmed by closing the drive water and exhaust water isolation valves in accordance with the Technical Specification Bases. Fuel movement was then halted. The Unit 1 Shift Supervisor instructed the PIPs to be reinstalled.

The PIPs were installed, RPIS full-in bypass box switches for all rods (20) were un-bypassed and the fuel movement activities were resumed.

CAUSE OF EVENT

The cause of moving fuel while the RPIS "full-in" indication was inoperable was due to inadequate procedure usage. The operations Shift Manager also became involved in troubleshooting and did not maintain an oversight role. This contributed to a misinterpretation of technical specifications, leading to the inappropriate decision to bypass the (20) RPIS full-in indications prior to commencing fuel movement.

REPORTABILITY ANALYSIS AND SAFETY ASSESSMENT

This event is reportable per 10 CFR 50.73(a)(2)(i)(B) as an operation or condition prohibited by Technical Specifications (TS) 3.9.4 which prohibits performing fuel movement when one or more required control rod position indication channels are inoperable.

Refueling equipment interlocks restrict the operation of the refueling equipment or the withdrawal of control rods to reinforce unit procedures that prevent the reactor from potentially achieving criticality during refueling. The refueling interlock circuitry senses the conditions of the refueling equipment and the control rods. Depending on the sensed conditions, interlocks are actuated to prevent the operation of the refueling equipment or the withdrawal of control rods.

The disconnection of the RPIS PIPs did not result in any damage to safety related equipment, offsite radiological releases, or personnel injuries. The Control Rod Drive Pumps had been stopped, thus preventing any potential control rod movement by removing the motive force. The control rods were therefore effectively hydraulically disarmed but not as suggested by the Tech Spec Bases 3.9.4 by closing the drive water and exhaust water isolation valves. Even though this condition was contrary to Tech Spec requirements, no change in reactivity resulted and no movement of the control rods occurred. Based on this information this reported condition had very low safety significance.

CORRECTIVE ACTIONS

Immediately following the event fuel movement was halted and the PIPS were installed. Qualifications were withdrawn for the personnel involved and a "stand down" was held with the Operations department where emphasis was stated on the importance of remaining in assigned roles.

Operations training will be presented using this event as operating experience during license training prior to the next refueling outage. Special focus will be placed on the technical specifications that apply during this evolution, the importance of staying within roles, and avoidance of making decisions driven by schedule concerns. Operations training will also perform specific pre-outage training on non-routine tasks (including control rod manipulations and fuel removal) prior to the next refueling outage.

ADDITIONAL INFORMATION

Other Systems Affected: None.

Failed Components Information: None.

Commitment Information: This report does not created any new licensing commitments.

Previous Similar Events:

On 2/25/2012, with the unit in Mode 5 for refueling, the "full-in" indication for Control Rod (CR) 22-27 was noted to be inoperable, and a required action statement (RAS) for TS 3.9.4 was entered. In accordance with the RAS the control room staff visually verified that the CR was fully inserted, action was taken to electrically disarm the associated CR drive, and a tag-out was conducted as part of the disarming action. A modified probe buffer card was installed to bypass the "full-in" indication signal in order to remove the rod block. Notation of the use of the modified probe buffer card was added to an existing TS RAS to track its installation and loss of the RPIS indication. At 2121 EST on 2/28/2012, the tag- out described above was cleared (i.e., removed) without removing the modified probe buffer card and without performing a functional test of the "full-in" indication prior to moving fuel in the reactor vessel. Fuel movement occurred from the time the tag-out was removed until 0817 EST on 3/212012 when the error was discovered; resulting in a condition prohibited by TS for CR position indication. The cause of this event was attributed to less than adequate procedural controls and the failure of involved personnel to effectively "self-check" as a human error prevention technique. A procedure change was implemented to require the shift supervisor to sign a tag-out if used to comply with a TS requirement. Because the lack of a tagout was cited in the 2016 event, the corrective actions from the 2012 event would not be expected to have prevented the condition reported in this LER.