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Turbine Bypasss Valve 2-2 (SP132A) Problem Analysis
	ML20129B727
Person / Time
Site:	Davis Besse
Issue date:	06/18/1985
From:	Raynes M; TOLEDO EDISON CO.
To:	;
Shared Package
ML20129B711	List: ML20129B706; ML20129B727;
References
	NUDOCS 8507290245
	Download: ML20129B727 (6)
	v • d • e

{{#Wiki_filter:_ _ _ _ _ _ _ _ o . . Turbine Bypass Valve 2-2 (SPl3A2) Problem Analysis Submitted by Matthew B. H.synes Plan 494 and 9b June 18, 1985 Page 1 of 3 This report has been prepared in accordance with the " Guidelines to Follow khen Troubleshooting or Perforrsing Investigative Actions into the Root Causes Surrounding the June 9, 1985 Reactor Trip, Rev. 2. Introduction It should be stated that all information obtained through data printouts and operator interviews points to the fact that the turbine bypass v.alve (TEV) fatted between 06:55 and 06:57 on the morning of the June 9, 1983 reactor trip. Summary of Dat_4 The following information was obtained through review of data and through interviews with the following people from the operattuna staff present at the time the valve is thought to have failed; William O'Connor, Louis Simon, Scott Wise, and Gene lit tlebrecht. When torrelating the pressure vs. time graph with the aldrie readout for the ttsse around the June 9, 19 M's reactor trip, the turbine bypass actpoint pressure of 1015 pets was escceded for approntmately two seconds before the Natn Steam Isolation Valves (M31Vs) closed whlCh t hanged the IoglC and prevented the TbV's from opening. On the morning of June 9, 198S the f ollowing sc<picure of events was taken to heat up the main steam line to the fiteam Generstor (SG) pressure and temperature in arcord4nte with procedure Pp 1*J'.03, Trip Recovery. The TBV header isolation valven '13 709 and MS 710 were closed at or around 03:40 along with the m4jority of the steam traps on the main steam line. At 05: 41 both M31V bypana valves were open to begin line heat up. These M11V bypass valves Hh 100A and MS lotA are one inch lines. For this reason must of the traps are closed to facilitate 4 quicker he4t up. Once the line had built up enough temperature and pressure the operators went down and opened the bypass 4round MS 709 and MS 710 to begin heatup of the TilV headers. At 06: 42 both MSIV's opened and between this time .a nd 06: 54 the isolation valven MS 709 and MS 110 to the ThV headers were opened. (It should be noted that valves MS 109 and M!! 710 are manually operated anit when being operated one must stand faring the TDV's on both headers no any failures on the fi1V's could have been noted. ) At this time the re4ctor operator reeptested that two TilV's on cas h header be isolated to control tha 50 pressure more easily. Ou both heasless the til and #3 valves worn isolatnd f rom the condenser just down stream leaving the 4 valveis on each header to rhntrol the 50 scoldown. Also around this time all ste.em traps should have been reopened. At OfuS4 t he 11 header ThV's 411 opened with just ". Pill 1J tontrolling and dumping to the condenser. At 06 r $$ the A he vder, which han pacet ion 4ble w4t er drainage, begin to have its ThV's open with I and 3 opening first. At 06 "s6.0009', thru 06136.01110 the TbV *iP11A2 showed not closed, rioned swepannt e twa(e and then had no i further readings. This is believed to be the time of failuse. At about

  ?               tSin time the interviewed operators, who were in the sontrol room, heard 4 loud creCiting sound like that he std f rom a water hammer. Drott Wise went l

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down to the TBV headers and found the valve SP13A2 in the present condi-tion. It should be noted that the A header as compared to the 8 header has a greater length of piping leading to it which may have had an effect ( on why no valves in the B header f ailed. l In reviewing maintenance done on SP13A2 the work was limited to repacking l work and calibration of the position indicator. The TBV SP13A2 has no record of maintenance testing and there are no scheduled surveillance tests for the TBVs. Chante Analysis The change analysis revealed no additional relevant data. Hypotheses The basis of the hypotheses were from the information provided by opera-tors and from inspection of the valve se found. With both the yoke and l the housing cracked many factors were taken into consideration. The two ! main facts that are very evident age the valve stem thread dimension which l were lossed in letter los #E85-152A File #MtiS.! and the fact that the pin i connector was in contact with the sleeve assembly. When the above two a factors were considered with the operator interviews the hypotheses were formed. 1 l I

l . . f l 3 1 Hypotheses ! 1. Water hammer

2. Valve internals assembled in a fashion to inhibit proper operation.

3. Valve positioner malfunction

! The most likely cause is thought to be a combination of hypotheses 1 and 2. l t 1

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2 . TOLEDO EDISDN Log No. E85-152A File No. EN 5.1 June 13, 1985 SP 13A2 and Associated Piping Walkdown 6/13/85 at 0930: Hanger ESD-3-H33 - No move =ent apparent on snubber S Header Valves and Actuators show no visible damage Valve upper stem thread shown in inches: . 13Al 7/8 13A2 2-1/8 13A3 1-1/16 1331 47/64 1332 1-1/8 1333 1-3/16

                >$ 712 no visual da age.

E3D-108-H5 - =inimal movement in south direction. No visual damage to insullation upstream'of valve.

                !$ 47 Line frce SP13A2 to condenser shows no visual signs of water hammer damage.

End 1010,6/13/85. Mkp N pal k N Matthew Rafnes Mike Kunnir Assistant Engineer Assistant Engineer THE TCLECC EC:00?J CCf/Da*4Y LCGCf4 oLAZA 300 MAC:5Cr4 AVE?JLE TOLECO C+0 43M2

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iihi loin entraniu- NR P Ald[1 in Ts Determine the Cause of Turbine Bypass Valve 2-2 (SP13A2) Failure H. Raynes , m....t ..en., l6/18/85 _ _ . - _ _ _ _ . . - _ _ . _ _ _ _ _ . _ _ _ _ _ - . - - - - - _ . _ _.~ i STEP

                                                                              .                                                                  6'li t Lt f               V/.lb?ll ()                              SI Aiti                  T Af4GE T             DATE MUUG E 14                                                                                                                                                                      to                                 DATC                      DATE              COMPL L T t D
                                                                                                                  . . _ _ _ - , - . . . ' _ " " _ . .A>N; tulle 1 <;

t j j ...i All steps of this Action Plan are to be performed in accordance 1

                    ! with the latest revision of " Guidelines to Follow When Trouble-shooting or Performing Investigative Actions into the Root                                                    ,                                         _._.. _ _                               _ _ . _                                  _ _. _

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                    ,    Causes Surrounding the June 9, 1985 Reactor Trip."

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                                                                                                                                       }                                                                      __           ._.       . . _ . _ _ _ _ ,                         . _

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l. To test Hypotheses 1 and 2 lH.Raynes l , . - ._ _ . ._

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Disassemble valve and inspect components for damage and i > -

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j improper assembly. Compare conditions to design and assembly ; { ! I information. ,i {. l .

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2. fTotestHypothesis3 l M. Raynes l ._. _ _ _ _ . . _ , _

_- 7 l, Test and/or calibrate valve positioner. ! i i _ _ _ _ . : i l !.__ -

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ML20129B727

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