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On August 31, 1984 McGuireUnit2trippedfrom100kpoweronaninadvertant2out of 4 channel power range high flux rate signal. The signal was generatedduring performance of a test procedure as one channel of the circuit was takenout of service for testing, and a power supply lead in a second channel wasmistakenly lifted, resulting in the 2 ont of 4 logic trip.

Personnel error is considered to have been the major cause of the event. Allplant systems responded as intended following the trip. Corrective actionsinclude counseling and instruction to appropriate personnel to avoid similarerrors of this nature in the future, procedural enhancements which recognize,and thereby guard against, the potential for such errors, and improved labelingof nuclear instrumentation cabinets.

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INTRODUCTION: On August 31, 1984, the unit two reactor tripped on a two out of fourpower range (P/R) high flux rate signal. This signal was generated inadvertentlyby Instrument and Electrical (IAE) personnel while performing a test procedure(Nuclear Instrumentation System (NIS) Power Range Rate Circuit and Bistable RelayDrivers Alignment (EIIS SYSTEM CODE: JC)).

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P/R channel 43 was placed in the trip mode in preparation for testing. The powersupply cable for P/R channel 42 was then mistakenly unplugged (instead of P/R channel43), placing P/R channel 42 in the trip mode also. With two P/R channels (out of atotal four channels) in the trip mode, a reactor trip was automatically initiated.,

Personnel error is considered to be the major cause of the event. However, proceduralenhancements and hardware additions (e.g. Labels for Cabinets) have been identifiedwhich should minimize the probability of occurrence.

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EVALUATION: The test procedure must be completed every 18 months to meet the surveil-lance requirement of Technical Specification 4.3.1.1 (channel _ calibration of P/Rneutron flux setpoints). This test is completed on one P/R channel at a time, usinga generic procedure with procedure steps that apply to any of the four P/R channels.The steps do not refer to the channel being tested; therefore, the IAE technicianperforming the test must keep in mind which channel is being tested.

On the day of the event, IAE technician A removed the instrument fuses on the frontof the N/I cabinet for P/R channel 43. IAE cechnician A walked around a row ofcabinets to get to the back of the N/I cabinet containing P/R channel 43 to disconnectchannel 43's input plugs. (IAE technician B, who was assisting with the test,stayed at the front of the cabinets). LAE technician A opened the cabinet door forP/R channel 42 instead of the door for channel 43, and disconnected the input plugson channel 42. This now placed both P/R channels 43 and 42 in the trip mode. Withtwo P/R channels in the trip mode, a reactor trip was initiated.

The label for P/R channel 43 is on a column between the cabinet doors for channel43 and 42. Had the label been on the door itself, it may have caught the techniciansattention and helped him realize that he was opening the wrong door. There areno labels inside the cabinet to identify the instrumentation contained within. Oncethe incorrect door was opened, it was unlikely that the technician would haverealized he was working on the wrong channel.

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Reactivity was promptly controlled by the reactor trip as the control rods inserted.Pressurizer pressure responded as expected, dropping to a minimum of 2015 psig beforerecovering and stabilizing at its reference value of 2235 psig. The pressurizerPORV's and Code Safety Valves were not challenged. Reactor coolant loop averagetemperature responded as desired, dropping to ~560*F and stabilizing there. Temp-erature decreased slightly to "559*F about 30 minutes after the reactor trip. Thisis slightly above the expected no-load value of 557*F. Wi'de range hot leg and coldleg temperatures also responded as designed. Pressurizer level control was normal;level dropped immediately after the trip to ~37%, and slowly decreased toward its no-load value of 25%. The pressurizer level stabilized at 25% about 30 minutes af terthe reactor trip.

Steam pressure peaked at 1132 psig, and stabilized at 1095 psig. This is within 3psi of its no-load target (1092 psig). The Main Steam Code Relief Valves (setpoint1170 psig) were not challenged. Steam generator level dropped immediately followingthe trip to the minimum level of 28% narrow range. Main feedwater was isolatedshortly after the reactor trip on reactor trip with coincident low average primarycoolant temperature. Both main feedwater pumps tripped on high discharge pressurefollowing the main feedwater isolation. All three auxiliary feedvater pumps wereactuated immediately after the reactor trip on indicated low-low steam generatorlevel, and were used by the operators to recover level. Auxiliary feedwater wassecured within 24 minutes after initiation as one main feedwater pump was returnedto service. Main feedwater was subsequently used to maintain the steam generatorlevels.

The levels were well controlled at all times. Level remained well abovethe post-trip low-low level setpoint of 12% narrow range.

Safety injection was not actuated during this event. The pressurizer PORV's andCode Safety Valves were not challenged. Indicated pressurizer and steam genera-tor levels remained on scale. The primary cooldown rate was approximately 30*F/hour, well below the Technical Specification limit of 100*F/ hour. No abnormalrelease of radioactivity occurred during this event, and there was up abnormalprimary leakage.

CORRECTIVE ACTION '

Appropriate individuala have reviewed the incident and have been made aware oftechniques to reduce the liklihood of recurrence of similar events. An evaluationwill be performed by November 1, 1984 to identify appropriate procedural improvements.

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DUKE POWER GOMPANYP.O. HOx 33180

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} HALH. TUCKER ~ TELEPHONE'

vna remainesrr (704) OTM531October 1, 1984"" = '' - -

Document Control DeskU. S. Nuclear Regulatory CommissionWashington, D. C. 20555

Subject: McGuire Nuclear Station, Unit 2Docket No. 50-370LER 370/84-21

Centlemen:

Pursuant to 10 CFR 50.73 Sections (a) (1) and (d), attached is Licensee Event-

Report 370/84-21 concerning a reactor trip resulting from an erroneous signal,which is submitted in accordance with5 50.73 (a)(2)(iv) . . Initial notificationof this event was made (pursuant to 5 50.72 Section (b)(2)(ii)) with the NRCOperations Center via the ENS on August 31, 1984. This event was consideredto be of no significance with respect to the health and safety of the public.

Very truly yours,

hh'

Hal B. Tucker

SAC /mjf

Attachment

cc: Mr. James P. O'Reilly, Regional AdministratorU. S. Nuclear Regulatory CommissionRegion II101 Marietta Street, NW, Suite 2900Atlanta, Georgia 30323

Records CenterInstitute of Nuclear Power Operations1100 Circle 75 Parkway, Suite 1500Atlanta, Georgia 30339

M&M Nuclear Consultants1221 Avenue of the AmericasNew York, New York 10020

Mr. W. T. OrdersNRC Resident InspectorMcGuire Nuclear Station-

American Nuclear Insurersc/o Dottie Sherman, ANI Library DThe Exchange, Suite 245 9

1270 Farmington Avenue

I \Farmington, CT 06032