IR 05000327/1986057

Insp Repts 50-327/86-57 & 50-328/86-57 on 861008-10.No Violation or Deviation Noted.Major Areas Inspected: Inadvertent Starts of Emergency Diesel Generators

ML20215F475
Person / Time
Site:	Sequoyah
Issue date:	11/17/1986
From:	Conlon T, Mcelhinney T, Ruff A NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
To:
Shared Package
ML20215F428	List: IR 05000327/1986057 ML20215F423
References
50-327-86-57, 50-328-86-57, NUDOCS 8612230409
Download: ML20215F475 (6)

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Satrfo UNITED STATES

'o NUCLEAR REGULATORY COMMISSION

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J* o REGION 11 g 101 MARIETTA STREET, * I *j ATLANTA, GEORGI A 30323

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Report Nos.: 50-327/86 57 and 50-328/86-57 Licensee: Tennessee ValleyJAuthority 6N38 A Lookout ~P1 ace'

1101 Market Street Chattanooga, TN 37402-2801 Docket Nos.: 5'0-327 and 50-328 . License Nos.: DPR-77 and DPR-79 Facility-Name: Sequoyah 1 and 2

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Inspection Conducted: October 8-10, 1986 Inspectors:

A. B. Ruff s / // 7/FM A) ate Signed X[ /

kV T. Fl McElhinney kl.3f/ l ?ffb

'y7 Cate Signed Approved by W / // / 7 - f (c/

T. E. Conlon, Chief, Plant Systems Section Date Signed Engineering Branch Division of Reactor Safety SUMMARY Scope: This special, announced inspection conducted in the areas of inadvertent starts of the Emergency Diesel Generators (EDG).

Results: No violations or deviations were identifie .

8612230409 861218 7 PDR ADOCK 0500 O

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REPORT DETAILS ' Persons Contacted Licensee Employees

• H. Abercrombie, Sequoyah, Site Manager

• P. R. Wallace, Sequoyah Plant Manager

• L. M. Nobles, Sequoyah Plant Manager

• H. R. Rogers, Plant Operation Review Staff (PORS)

• G. B. Kirk, Compliance Licensing Supervisor

• R. L. Collins, Project Electrical Group Leader

• D. L. Widner, Modification Supervisor

• J. A. Niak, Modification Supervisor

• G. Duggin, Electrical Engineer, P0RS D. Cross, Shift Engineer

• B. Schofield, Licensing Engineer Other licensee employees contacted included engineers, technicians, operators, security force members, and office personne NRC Resident Inspectors

• K. Jenison

! *D. Loveless

• P. Harmon

• Attended exit interview Exit Interview The inspection scope and findings were summarized on October 10, 1986, with

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those persons indicated in paragraph 1 above. The inspector described the areas inspected and discussed in detail the inspection finding No dissenting comments were received from the license The following new i item was identified during this inspection.

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Inspector Followup Item (IFI) 50-327, 328/86-57-01, Electrical Coor-dination Required for Feeder and Branch Fuses for Circuit Similar to those shown on Print 45N 767-5, R12, Paragraph 5.(b).

f The licensee did not identify as proprietary any of the materials provided

to or reviewed by the inspector during this inspection.

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. Licensee Action on Previous Enforcement Matters This subject was not addressed in the inspectio . Unresolved Items Unresolved items were not identified during the inspectio . Followup of Licensee Event Notifications An examination was made of the licensee's telephone notifications of

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September 14 and October 2, 1986 events that caused the automatic start of their Emergency Diesel Generators (EDG). These events occurred with both plants in Mode 5 (zero percent power, 300 psig, and loop temperatures approximately 124*F) and all technical specification satisfied. The plants have been shut down since August 1985, to correct and resolve certain administrative, design, operational, maintenance, and electrical equipment environmental qualification issue One of the items that was being performed, with the plant in the above conditions, was the upgrading of fuses and verification of proper fuse Bussman KAZ actuators (Signal indicating, Alarm activating devices) that were being used as a six amp protective devices or as alarm activating devices in the 125 VDC circuits were being replaced as part of this work ite The licensee's representative stated that Bussman MIS fuses, specified by Engineering Change Notice (ECN) 6747, were the replacement

components for the KAZ actuators, September 14, 1986 Event On September 14, 1986, the EDGs started automatically while personnel were performing a portion of the Sequoyah fuse upgrade / verification

, progra The work was being performed in a panel (Vital Battery Board IV) that is shared by both units (Units 1 and 2). Some of the

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circuits in this panel supply power to Unit 1 circuits and some supply power to Unit 2 circuit The electrical schematic (print) for this panel is the same for both units. Two sets of the prints are in the main control room (MCR) - one stamped " Unit 1 Only" and the other

" Unit 2 Only". When field work is completed, the primary prints are

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marked up to reflect completed work on a unitized basis. These primary prints include those that are located in the MC The protective

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devices (KAZ actuators and/or fuses) that were being checked in this panel were indicated as spares on the " Unit 1 Only" print but on the

" Unit 2 Only" print, these spare devices were designated as activ The activation of these spare protective device for a Unit 2 circuit was accomplished by a work plan and the " Unit 2 Only" print was marked up to reflect this modificatio However, on September 14, 1986, the

" Unit 1 Only" print was only being used during the fuse verification /

upgrade work for the panel indicated above and while replacing the e

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active devices (indicated as spares on the " Unit 1 Only" print) power was inadvertently removed from logic relay panel for a shutdown boar The standby EDGs started automatically as designed, but since electrical power was not lost to any of the boards, none of the EDGs tied onto their shutdown boards. During this event, the normal diesel generator cooling water for 1B-B diesel was isolated by an unusual system lineup. The unusual lineup was not recognized by operating personnel at the time the lineup was made for ERCW strainer wor Consequently, the 18-B DG tripped on high water temperature when it was returned to nortnal. The licensee indicated that the EDG sustained no damage as the result of this even This event would not have happened if personnel used both " Unit 1 Only" and " Unit 2 Only" prints or if unitized prints for shared panels, and/or board, were a single print that showed all circuit off of the panel and/or boards regardless of unit or plant affiliation. The licensee has committed to initiate a program to merge the unitized prints (" Unit 1 Only" and " Unit 2 Only') into a single " Unit 1 and Unit 2" print for components, systems, and electrical boards or panels that are shared by both unit The merging of prints for shared equipment is to be completed before restart of a unit. Common equipment and/or systems that are identified by "zero" (0) in the first portion of the unique identifiers are different than shared equipment as discussed abov The " common" equipment is not unitized as evidence by the unique identifiers and/or by the fact that design drawing (print) designate them as " General" in the title section of the drawing or the drawings are stamped " Unit 0". The common equipment drawings (prints) are not covered by this commitment. Correct prints and their mark ups for these common equipment, systems, components, etc. should be included as primary prints in the MCR for both unit The above discussion indicates that a violation of 10 CFR 50 Appendix B, Criterion V, " Instructions, Procedures, and Drawings" occurred because procedures were not of a type appropriate to the circumstance Unitized Prints (" Unit 1 Only" and Unit 2 Only") that have shared equipment were marked up only for the unit that was changed by the modification. Both prints should have been changed. This violation was discussed with resident inspectors and regional personnel and the following were considered:

(1) The violation was identified by the license (2) The violation fits in Severity Level IV or (3) The violation was reported, if require (4) Adequate corrective measures were being established and implemente (5) It is not a violation that could reasonably be expected to have been prevented by the licensee's corrective action for a previous violatio ..

Based on the above considerations, it was concluded that the violation would not be cited based on 10 CFR 2, Appendix C, Section As indicated above, the licensee committed to merge the unitized prints for shared equipment into a single print (" Unit 1 and 2") and to correct the necessary procedures for this action before startup of a unit. This will be tracked under previous IFI 327, 328/86-49-0 b. October 2, 1986 Event On October 2,1986, Sequoyah experienced an auto start of three Emergency Diesel Generators (EDGs 1A-A, 2A-A, 2B-B) when a fuse blew in an associated 125 Volt DC emergency start circuit (vital battery circuit C-42). The licensee investigation revealed that personnel working in the torque switch compartment of a Limitorque Motor Valve Operator created an inadvertent short circui The work on this valve (ERCW Supply Valve to an EDG) was for torque switch bypass and was authorized by Work Plan 12090. Except for some of the circuits that pickup limit switch positions, electrical control power and motor power had been removed from the valve operator. Personnel working in the torque switch compartaent apparently came in contact with the energized limit switch circuits to create the short circuit. The short circuit blew a six ampere feeder fuse rather than the six amp branch fuse in the 125 VDC emergency start circuit for the EDGs. This de-energization of the circuit, fed by the six amp feeder fuse, caused the EDGs to start automatically. This action also resulted in the loss of control power in a branch circuit to the alternate ERCW supply valve to the affected ED With the normal ERCW supply valve tagged out for main-tenance and the los5 )f control power for the alternate valve, an operator had to locc.ly open the valve in the diesel building to prevent overheating of the engin This event showed that the feeder and branch fuses have the same six ampere ratin This event in all probability would not have happened if proper electrical coordination existed between the feeder circuit fuses and branch circuit fuses. With proper coordination, the branch circuit fuse should have blown so that the feeder circuit and other branch circuits in the 125 VDC Battery Board would not be affected. The licensee stated that fuses and/or alarm activating devices in the branch circuits were installed for isolation during maintenance and that coordination between the feeder and branch circuits was not

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intende However, as a result of this event, the licensee is re-evaluating the coordination of this feeder / branch circuits and circuits of similar desig The licensee stated that electrical coordination would be implemented and corrected for these type of circuits and that this action would be accomplished prior to start up of a uni The above discussion indicates an apparent violation of 10 CFR 50, Appendix B, Criterion 3 (Design Control). The circuit design was deficient in that the selection of protective devices in the subject feeder / branch circuits, which are essential to the safety-related function of the system, were not electrically coordinate This apparent violation was discussed with the resident inspectors, and regional personnel and the following were considered:

(1) The violation was identified by the license (2) The violation fits in Severity Level IV or (3) The violation was reported, if require (4) Adequate corrective measures were being established and implemente (5) It was not a violation that could reasonably be expected to have been prevented by the licensee's corrective action for a previous violatio Based upon the above considerations, it was concluded that the violation would not be cited based on 10 CFR 2 Appendix C, Section The inspector informed the licensae that this would be an inspector tollowup item 50-327, 328/86-57-01, Electrical Coordination Required Between Feeder and Branch Fuses for Circuits similar to those shown on Print 45N767-5 R-12, and would be reviewed before startup of a unit.