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LER 93-004-00:on 930428,plant Entered Mode 2 W/Afw Pump Turbine Main Steam Line Crossover Check Valve MS735 in Open Position.Caused by Inappropriate Use of Engineering Judgement.Valve MS735 closed.W/930726 Ltr
	ML20046B601
Person / Time
Site:	Davis Besse
Issue date:	07/26/1993
From:	Antrassian A, Jeffery Wood; TOLEDO EDISON CO.
To:	; NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
	AB-93-0027, AB-93-27, LER-93-004, LER-93-4, NP-33-93-004, NP-33-93-4, NUDOCS 9308050217
	Download: ML20046B601 (6)
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. I TOLEDO

%mm EDISON r A Cente<ior Energy Company EDISON PLAZA 300 MADISDN AVENUE 3 TOLEDO. OHIO 436524001 AB-93-0027 '

NP-33-93-004 l

Docket No. 50-346 ,

License No. NPF-3 July 26, 1993 United States Nuclear Regulatory Commission Document Control Desk Washington, D. C. 20555 '

Gentlemen LER 93-004 Davis-Besse Nuclear Power Station, Unit No. 1 7 Date of Occurrence - April 28, 1993 Enclosed please find Licensee Event Report 93-004, which is being submitted to provide 30 days written notification of the subject occurrence. This LER is being submitted in accordance with 10 CFR 50.73(a)(2)(1). t Very truly yours,

/

Jo n K. Wood Plant Manager Davis-Eesse Nuclear Power Station J1'W/ dle Enclosure ,

cc Mr. John B. Martin Regional Administrator USNRC Region III 1 +

Mr. Stan Stasek DB-1 NRC Sr. Resident Inspector 9308050217 930726 PDR ADDCK 05000346 Ye D i S PDR 9[id -

r Al NRC f ORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED DV OMB NO. 3150-0104 i (5 sa EXPIRES 5/31/95 F LTIMA?lD BUrOEN PLH Hf SPON'.sE TO CouPL Y W:TH THis it#0nMAT ON COuf CTION nEQufst 50 0 HRS. FORWARD LICENSEE EVENT REPORT (LER) coaut,as nrwoNa sonoru rsnum TO w iwOnunoN AND RECORDS t/ANAGEME NT pr sANOH (MNBO 7714), U S. NUC11AR RrGULATORY COMMCL'ON, WASHINGTON, DC 205%.0901, AND TO THE PAPlHNDOM REDUCTION PROJE CT 13150-0104L Orrict Or (See reverse for required number of digits / characters for each block) MANAGt ME NT AND DuDGE7, W ASHINGTON. DC 20503 l

f ACIUTY NAME (1) DOCKf1 NUMhEH (2) PAGE(3} j Davis-Desse Unit Number 1 05000 -346 10F 05 !

TITLE (4)

Mode 2 Entry with Auxiliary Feedwater Train 2 Inoperable (TS 3.0.4 Violation)

EVENT DATE (5) LER NUMBER (6 hEPORT NUMBER (7) OTHER FACILITIES INVOLVED (8)

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04 28 93 93 004 00 l 26 93 05000 07 OPERATING THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR 5: fCheck one or more) (11)

MODE (9) 2 20 402(b) 20 4051c) 50.73(a)(2)Dv) 73.71(b)

POWER 20 405taH1)(i) 50 35(c)(1) 50.73(a)(2)(v) 73 71(c) ;

LEVEL (10) 000 20 405(a)(1)W) 50.36(c)(2) 50.73(a)(2)(vn) OTHER i

~ nrwy m Abw I 20.405(a)(1)(ud X 50 73(a)(2)D) 50.73(a)(2)(vui)(A) wo. .no m Tent, Nrc -

20.405(a)(1)(iv) 50.73(a)(2)(u) 50.73(a)(2)(vni)(B) Fmm 3%A) b 20 405(a)(1Hv) 50 73(a)(2)0n) 50.73(a)(2)4) f LICENSEE CONTACT FOR THIS LER (12) !

uvE 1aLG@l NJUN k Musoe Ares Gooe) !

Andrew V. Antrassian, Engineer - Licensing (419) 321-7908 !

COMPLETE ONE LINE FOR EACH COMPONENT FAILURE DESCRIBED IN THIS REPORT (13) i cAust selv cou"Ouric M ANur ACTunt a cAact sysTEu coumNE N! MANUTACTURf-R ,

SUPPLEMENTAL REPORT EXPECTED (14) EXPECTED "" DA' ^" !

I ye s SUBMISSION m ye., ,mry, ortcTI o cow wCN Der; X DATE (15)

ABSTRACT (Limit to 1400 spaces a e., approximately 15 singte-spaced typewntten lines) (16) ,

On April 28, 1993, at 1212 hours0.014 days 0.337 hours 0.002 weeks 4.61166e-4 months , during startup from the eighth refueling outage (8RFO), the plant entered Mode 2 with the auxiliary feedwater pump j turbine main steam line crossover check valve MS735 in the open position. i Valve MS735 is required to close in order to maintain functionality of auxiliary feedvater pump turbine (AFPT) 2 in the event of a high energy line f break (HELB) upstream of the valve. A subsequent engineering evaluation could i not verify that valve MS735 vould have closed under such conditions. t.s such, ,

this constitutes a violation of Technical Specification 3.0.4. ;

It is believed that check valve MS735 stayed in the open position following l

system testing which was performed prior to entry into Mode 2. Valve MS 735 ,

remained open due to valve packing load. A modification was made during 8RF0 vhich replaced check valve MS735 vith a new valve having an external shaft and ;

. packing. The design report for the modification stated that a packing ;

friction load up to 60 ft-los could be expected. Testing verified that approximately 40 to 45 ft-lbs of torque on the valve stem are required in l order to initiate valve motion in either direction. This was not properly ;

analyzed during the design modification process. '

Valve MS735 was closed at approximately 1500 hours0.0174 days 0.417 hours 0.00248 weeks 5.7075e-4 months on April 28, 1993, thereby returning AFPT 2 to operable status. l we ronu 3.+ m f

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Davis-Besse Unit Number 1 93 004 00 l TLX1 pt enore ss.ete na reostets use ecoarow comes of NHC f orrn 36,tA) (17} f Description of Occurrence:

i on April 28, 1993, at 1212 hours0.014 days 0.337 hours 0.002 weeks 4.61166e-4 months , during startup from the eighth refueling i outage (8RFO), the plant entered Mode 2 vith the auxiliary feedvater (BA) pump '

turbine main steam line crossover check valve MS735 in the open position. l Valve MS735 is required to close in order to maintain functionality of !

auxiliary feedvater pump turbine (AFFT) 2 in the event of a high energy line -j break (HELB) upstream of the valve. A subsequent engineering evaluation could r not verify that valve MS735 vould have closed under such conditions. As such, I the April 28, 1993 mode change constitutes a violation of Technical l Specification (TS) 3.0.4 which prohibits mode changes unless the Limiting !

Conditions for Operation are met without reliance on Action Statements and is {

reportable under the provisions of 10CFR50.73(a)(2)(i)(B).

1 This violation of Technical Specification 3.0.4 was discovered on June 25, 1993 during a Quality Assurance surveillance of activities associated with !

modification 91-0044. Modification 91-0044 replaced auxiliary feedvater pump :

turbine main steam line crossover check valves MS734 and MS735 during 8RFO. i The existing check valves vere replaced with new valves having an external i shaft and packing. The modification is intended to reduce wear of the valve ;

seats caused by continuous movement of the disc on its seat. The design !

report for the modification stated that a packing friction load up to 60 !

ft-lbs could be expected. Testing verified that approximately 40 to 45 ft-lbs i of torque on the valve stem are required in order to initiate valve motion in ;

either direction. j On April 27, 1993, at approximately 2145 hours0.0248 days 0.596 hours 0.00355 weeks 8.161725e-4 months MS735 vas cycled fully open and closed as part of the acceptance criteria for DB-PF-03069, Check Valve ,

Reverse Flow Tests. It is believed that MS735 stayed in the open position '

following this test rendering AFPT 2 inoperable. Based on the design report j for the modification, valve position was not an operability factor for this i application and the valve, regardless of its position, vould still perform its i safety function (i.e., the valve would have closed in the event of a HELB). I i

Operations declared the Auxiliary Feedvater (AFW) system operable on April 28, 1993, at 0700 hours0.0081 days 0.194 hours 0.00116 weeks 2.6635e-4 months and the plant subsequently entered Mode 2 at 1212 hours0.014 days 0.337 hours 0.002 weeks 4.61166e-4 months . ,

At 1400 hours0.0162 days 0.389 hours 0.00231 weeks 5.327e-4 months on April 28, 1993, Nuclear, Performance, and Systems Engineering ;

discussed the new valves' application. Nuclear Engineering stated that their !'

calculations for a HELB did not justify the 60 f t-lbs allowed by the' design and that the valve must be in the closed position to be operable. At .

approximately 1500 hours0.0174 days 0.417 hours 0.00248 weeks 5.7075e-4 months on April 28, 1993, valve MS735 vas found open by a }

System Engineer. Valve MS735 was immediately closed by the System Engineer, i returning AFPT 2 to operable status. Operations was not informed of this action. ;

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Davis-Besse Unit Number 1 93 004 00 ;

t rex, e ~, ,m. nw.va .ma..n., a wwauu o n Description of Occurrence (continued): ,

Auxiliary feedvater pump turbine 2 was inoperable for approximately 17 hours1.967593e-4 days 0.00472 hours 2.810847e-5 weeks 6.4685e-6 months . i This is within the 72 hour8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months allowable outage time of Technical Specification 3.7.1.2. Therefore, no violation of Technical Specification 3.7.1.2 occurred.

Toledo Edison originally identified the concern regarding packing loads on the f new MS734 and MS735 valves as a result of reverse flow testing performed on ,

the valves at approximately 1300 hours0.015 days 0.361 hours 0.00215 weeks 4.9465e-4 months on April 27, 1993. All required testing of the Auxiliary Feedvater System (AFV) was satisfactorily completed ,

prior to entry into Mode 2 on April 28, 1993. Potential Condition Adverse To l

, Quality Report (PCAQR) 93-0287 was initiated at 1830 hours0.0212 days 0.508 hours 0.00303 weeks 6.96315e-4 months on April 28, 1993 ;

to document and resolve the packing load concern, at which time, Operations 1

personnel verified that both MS734 and MS735 vere closed. This, however, was after valve MS735 was closed at 1500 hours0.0174 days 0.417 hours 0.00248 weeks 5.7075e-4 months . As such, Operations was not aware ;

, that a mode change had been made with a potentially inoperable AFPT 2.

As part of PCAOR 93-0287, a safety evaluation was completed which demonstrated that operability of the AFV system was not affected provided that valves MS734 and MS735 are periodically verified to be closed. As stated above, valves ,

M5734 and MS735 are required to close in order to maintain functionality of '

the AFPTs in the event of a HELB upstream of the valves. Field testing has demonstrated that sufficient differential pressure exists to open the new valves and supply steam to the AFPTs. Operations Standing Order 93-012, j requiring periodic visual inspection of valve position was issued on April 28, 1993. In addition, procedures which require the operation of the auxiliary ,

feedvater pumps have been revised to require verification that the valves are closed following operation of the pumps.

After the potential violation of Technical Specification 3.0.4 was identified ,

on June 25, 1993, an engineering evaluation was initiated to determine if valve MS735 vould have closed in the event of a HELB upstream of the valve. i The evaluation determined that if the valve disc is fully in the flow stream l (nearly closed), adequate torque vill be developed to close the valve for any postulated break location upstream of the valve. However, the as-found !

position of u s '4S735 could not be determined and was conservatively assumed ,

to be fully opened. Given this assumption, Engineering could not verify that !

valve MS735 vould have closed. ;

Apparent Cause of Occurrence:

The apparent cause of this event is inappropriate use of engineering judgment during development of Modification 91-0044. The design report for :

Modification 91-0044 addresses the packing load associated with the new valves !

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Davis-Besse Unit Number 1 93 004 00 rExT w mv, n.= ,, raw a m .w en..s a wic Fwm m; o n i Apparent Cause of Occurrence (continued):

and conservatively assumes that 60 ft-lbs of torque ate required to overcome {

the packing friction. However, engineering judgment was used to determine that under line break conditions the disc would easlly develop 60 ft-lbs of torque. A subsequent engineering analysis has shown that this is not the case for all potential HELB locations. In addition, Engineering Policy ED-01, "Use of Engineering Judgment / Assumptions," was not followed. The policy requires that the use of engineering judgments or assumptions shall be documented by including a brief statement of the basis for the judgment or assumption in a sufficiently clear manner to permit another engineer versed in the same discipline to understand the preparer's thought process. Had this policy been i followed, it is more likely that the erroneous engineering judgment vould have been identified during the review of Hodifications 91-0044.

Valve MS735 was open as a result of system testing performed prior to Mode 2 entry. The valve remained open due to the packing load present in the nev style valve installed during 8RFO.

The failure to identify the violation of Technical Specification 3.0.4 until June 25, 1993, is attributed to a breakdown in communication from Systems j Engineering to Operations. The System Engineer who closed MS735 did not communicate his actions to Operations. He should not have closed the valve;-

this is an Operations activity. His findings and, in this case his actions, should have been immediately communicated to Operations. Tne reportability concern was identified during a Quality Assurance surveillance of the replacement of MS734 and HS735 which was conducted May 3 through June 30,

1993. t Analysis of Occurrence- '

, i This event is of minimal safety significance.

Both trains of AFV vere functional during the approximately 17 hours1.967593e-4 days 0.00472 hours 2.810847e-5 weeks 6.4685e-6 months that AFPT 2 vas inoperable. The only situation which could have caused a concern .

vould have been a HELB upstream of valve MS735 which would have affected the operability of AFPT 2. In addition, the as-found position of valve MS735 could not be determined. If the valve was only partially open, it is likely

that adequate torque would be deseloped to close the valve for any postulated break location. There was no operational occurrence which would have required t the AFV system to function during this period.

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Davis-Besse Unit Number 1 93 004 00 wcf w r,,,,, ua, ,, a.nea me . man. cwmr +c +w my vn Corrective Action:

Valve MS735 was closed at approximately 1500 hours0.0174 days 0.417 hours 0.00248 weeks 5.7075e-4 months on April 28, 1993, thereby returning AFPT 2 to operable status.

Licensee Event Report 93-004 vill become part of a required reading package for Design Engineering. Engineering Management vill also utilize this required reading to reinforce the importance of properly documenting engineering judgments or assumptions in accordance with Engineering Policy ED-01. This action vill be completed by August 31, 1993.

The System Engineer involved with manipulation of valve MS735 was disciplined.

Operations Standing Order 93-012, requiring periodic visual inspection of valve position was issued on April 28, 1993.

Procedures which require the operation of the Auxiliary Feedvater Pumps have been revised to require verification that the valves are closed following operation of the pumps.

Failure Data:

There are no LERs in the previous three years involving a Technical Specification 3.0.4 violation due to inappropriate use of engineering judgment. LER 92-002, submitted May 20, 1993, involved a Technical Specification 3.0.4 violation which resulted from an incorrect assumption regarding equipment operability. The corrective actions taken in response to LER 92-002 vould not be expected to prevent the event described in this LER.

i NP 33-93-004 PCAO No. 93-0287 ;

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NRC rORv x6A (5 s23

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ML20046B601

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