ML062720116

Special Inspection Charter to Evaluate the Palo Verde Nuclear Generating Station Unit 3 Emergency Diesel Generator Failure

ML062720116
Person / Time
Site:	Palo Verde
Issue date:	09/29/2006
From:	Howell A NRC/RGN-IV/DRP
To:	Michael Bloodgood, Hay M, Scott Rutenkroger NRC/RGN-IV/DRP/RPB-D, Division of Reactor Safety IV
References
Download: ML062720116 (4)

Text

September 29, 20 06 MEM ORAND UM TO: Mic hael Hay, Senio r Proje ct Engi neer, Project Branch D, Division of Reactor Proj ects (DRP)

Dr. Sc ott Rut enkroger, React or Insp ector, Engine ering B ranch 1, Div isio n of Rea ctor Sa fety Mic hael Blood good, R eactor Inspe ctor, Project Branch D , DRP - Traini ng FROM: Arthur T. Howell III, Director , DRP

/RA/ AVe gel for SUBJE CT: SPECIAL INSPECTION CHARTER TO EVALUATE THE PALO VERDE NUCLEAR GENERATING STATI ON UNIT 3 EMERGENCY DIESEL GENERATOR FAILURE A Special Inspection Team is being cha rtered in respo nse to the Pa lo Verde N uclear Generat ing Sta tion U nit 3 Emergen cy Di esel Generat or (ED G) failu re. The dies el fai led to deve lop a n outp ut vo ltage w hen st arted fo r a sur veil lance test. The li censee determ ined that a modification to the field flashi ng relay cau sed the failure. You are he reby desi gnated as the Special In spection Team members. Mr. Hay is designate d as the team l eader. The assi gned SRA to supp ort the team is Mike Runy on.A.Basis On Ju ly 25, 2 006, Uni t 3, T rain A, E DG fai led to d eve lop outp ut v olta ge du ring a surveillance test. The licensee's root cause det ermined plastic debris potentially prevented a uxilia ry contacts from prop erly function ing resulting i n shorting out o f the gener ator f ield durin g star tup preve nting a proper f ield flas h. Two rep lacemen t relays obtai ned from the li censee ware house exhi bited the sa me degra ded co nditi on. A third relay w as satisfactorily tested and i nstalled. The diesel w as subsequently tested and declared ope rable on Jul y 26, 2006

.On Se ptem ber 2 2, 20 06, U nit 3, Tra in A , ED G fai led to d eve lop outp ut v olta ge du ring a surveill ance test. The l icensee dete rmined that the same auxil iary contac t which failed in July 2006 wa s faulty. The l icensee id entified that thi s failure w as attributed to a bent metal actuator arm that is used to actuate the auxiliary contacts associated with the field shorti ng circ uit. A dditi onall y, the lice nsee d etermi ned th is be nt metal actua tor arm potentially exits in all six EDG's at the facility. Based on previous failures it appears this bent a rm is th e unde rlyi ng root cause for the fi eld s hortin g auxi liary conta cts fail ure to operat e reli ably , and t his co nditi on is transp ortabl e to al l ope rating EDG's a t the fac ilit y.

Michael Hay-2-This Special Inspection Team is chart ered to review the generic impact of the re lay's bent arms on the other Palo V erde Emergency Diesel Gene rators as we ll as any pote ntia l im pact on o ther nuc lea r pl ants. The team is a lso to re vie w th e de sign cha nge method and rev iews that the license e used w hen making the rel ay modificati ons. The team will also rev iew the licensee's operabili ty determinati on and correcti ve action program for determining the root cause and correction of the diesel's failure.B.Scope The t eam i s ex pect ed to add ress the foll owi ng: 1.Develop a complete sco pe of the failures of all Palo Verde Emergency Diesel Generators to dev elop an ou tput voltage.

2.Review the extent of condition d etermination for thi s condition (current and pri or K1 relay failures) and whether the licensee's actions are compr ehensive. This shoul d inc lude potent ial fo r other dies el fai lures. 3.Revi ew th e lic ensee's de termin ation of the c ause o f any d esign d eficie ncies. Independently verify key assumptions a nd facts. If avail able, determin e if the licensee's root cu rrent and prior cause ana lysis and cor rective a ctions h ave addressed the extent of condi tion for problems with the emergency dies el generators K1 rel ays.4.Determine if the Technical Sp ecifications w ere met when the diesel failed.5.Review and assess the correctiv e actions for curre nt and past si milar failures.

6.Review the licen see's EDG op erability determination to evalu ate the emergency diese l gene rator's oper abil ity. 7.Collect da ta as necessary to support a ri sk analysi s.8.Determine if thi s issue has generic impli cations to oth er nuclear facil ities.C.Guidance Inspection Pro cedure 93812, "Special In spection," prov ides addi tional guida nce to be used by th e Special Inspection Team.

Your duties will be as descri bed in Inspe ction Procedure 9381

2. The inspec tion should emphasize fact-finding in its review of the circumstances su rrounding the ev ent. It is not the responsib ility o f the team to exami ne the regulatory process. Safety concerns ide ntified that are not directly related to the event shoul d be reported to the Region IV office for appropriate action.The Team will report to the si te, conduct an entrance, and b egin inspecti on no later than October 4, 200 6. While o n site , you wil l prov ide d aily status briefi ngs to R egion IV Michael Hay-3-manageme nt, w ho w ill coordi nate w ith th e Office o f Nucle ar Rea ctor Re gulati on, to ensure that al l other parti es are kept informed.

A report documen ting the results of the inspection should be issued w ithin 30 d ays of the compl etion of the in spection.This Charter may be modified sh ould the tea m develop significant new information that warrants rev iew. Sh ould you have any questions conc erning this Ch arter, contact me at (817) 8 60-824 8. cc via E-mail:

B. Ma llett T. Gwynn D. Chamberlain R. Caniano M. Fiel ds V. D rick s J. Lamb W. Maier T. Pruet t D. Terao A. Vegel G. Warnick SUNSI Rev iew Comp leted: _FLB

__ADAM S: / Yes G No Ini tials: FLB

/ Publi cly Av ailable G Non-Publ icly Av ailable G Sensitive

/ Non-Sensit ive S:\DRP\DRPD IR\CHARTER\PV 2006.wpd

M L062720116 RIV:SP E:DRP/B D:DRP FLBrus h;mjs ATHowell/R A//R A/9/28/06 9/29/06 OFFICIAL RECORD COPY T=Telephone E=E-mai l F=Fax