ML20005E861

LER 89-033-00:on 891205,safety Injection Occurred on Low Steamline Pressure When Steam Generator a MSIV Opened, Generating Safety Injection Actuation Signal.Caused by Procedure Inadequacy.Procedure changed.W/900104 Ltr

ML20005E861
Person / Time
Site:	Millstone
Issue date:	01/04/1990
From:	Langan J, Scace S NORTHEAST NUCLEAR ENERGY CO., NORTHEAST UTILITIES
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
LER-89-033, MP-90-011, NUDOCS 9001120009
Download: ML20005E861 (4)

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U.S. Nuclear Regulatory Commission  ! Document Control Desk

                          . Washington, D.C. ' 20555

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Reference:

Facility Operating License No. NPF-49  :

                                                   - Docket No.-50-423 Licensee Event. Report 89-033-00
                          ' Gentle' men:                                                                                                             i This letter forwards Licensee Event Report 89-033-00 required to.be submitted within thirty (30) days,' pursuant to 10CFR50.73(a)(2)(iv), any event or condition that resulted in the automatic actuation of any Engineered Safety Feature, f

Very truly yours, , NORTHEAST NUCLEAR ENERGY COMPANY 4 Steph

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E. Scace Station Superintendent - Millswne Nuclear Power Station 1

                          ~ SES/JAL:tp -                                                                                                            3

Attachment:

LER 89-033-00 o 1 i cc: W. T. Russell, Region 1 Administrator L W. J. Raymond, Senior Resident Inspector, Millstone Unit Nos.1, 2 and 3 D. H. Jaffe, NRC Project Manager, Millstone Unit No. 3 1; t ' u [ l l 9001120009 900104 i PDR ADOCK 05000423 l1 S PLC

t#tC Form 366 - U S. NUCLEAR REGULATORY COMMISSION APPROVED OMB No, 31bO-010s (649) , EXPIRE S: 4/30/92 t Estimatsc buroen per responsy to comply with this informa1 ion colection rsouest: 60 0 hrs. Forwarc LICENSEE EVENT REPORT (LER)' EEtMa'nye'nin *BrN@s$0i'"* "s*Illeiea, u

                                                                                                     ' Repwatory Commission. Wasnmoton, De 20565 and to -

the Paperwork Reduction Pro 3ect (316Cw0104). Othee of Management anc Buopet Wasn noton DC 20503 F ACILIT Y NAME (1) DQWElNJMbW ta W 51111 stone Nuclear Power Station Unit 3 ' o f 6l ol of 01412 l 3 1lOFl 0l 3 IllLE (41 , Safety In_iection on Low Steamline Pressure Due to Procecural inadequacy EVENT DATE (Si LER NUMBEm 16) REPORT DATE (7) OTHER F ACfLITIES INVOLVED f8i MONTH DAY YEAR YEAR WN MONTH DAY YEAR F AC4 TTY NAMES of si of of of l (

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1l2 0l5 8 9 fs l 9 0l3l3 0l 0 0 l1 0l 4 9l 0 015l 0101 ol l l OPER ATING . THS REPORT IS BEING SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR 6: (Check one or more of the tohowing)(11) 20.402f t0 _ 20 402(c) J 60.73(aH2)(iv) 73.71(b) po R 20.40$la)(1)(l) 50.36(cH1) 50. 73(a)(2Hv) 73.71(c) no, 0l0l0 20 40slaH1uiu so.36(c)(2) so.73. (a)(2)ivid X (TgA, (gogitgn , 20 405ta)(1Hin) 60.73(aH2)f u 50. 73(a)(2 H vh0 ( A) Text. NRC Form 366A) i .

20. 406 t a)(1)(iv) 60.73(aM?)(10 50.73(a)(2)(viii)(B) Technical Spec.

20 406ra)(i nfwi 50 73(aH2)(lill 50.73 f al f2)lx) 3.5.2 & 6.9.2 LICENSEE CONT ACT FOR THIS LER (12) NAME TELEPHONE NOVBER 'i Jeffry A, Langan, Ext. 5544 2j0l3 4]4l7(~j'1l7l9l1 COMDLETE ONE LINE FOR E AcH COMPONENT F AILURE DESCR: BED IN THIS AEPORT (13) CAUSE SYSTElv COMPONENT N 7d CAUSE SYSTEM COMDONENT [[ 7d I l! I I I I I IIl i I I I II I I I I I lli I I I SUPPLEMENTAL REPOAT EXPECTED (14) MONTH DAY YEAR

                                                                                                                                  ,    g SUBMIS$10N YES (H yes. comoiste EXPECTED SUBM:SSION DATE)                                                                    DATE (15)
                                                                           % NO                                                                     g      l     l I~    ABSTRACT (Limit to 1400 spaces. i.e.. apprommatety fifteen smgie-soace typewntten hnes) (16) l

! At 2157 hours on December 5,1989, in Slode 3 (Hot Standby), 557 degrees and 2250 psia, a safety l injection occurred (SI) on low steamline pressure (rate compensated) when the "A" steam generator hiain Steam Isolation Valve (h1SIV) was opened. A review of the steam generator pressure recorder after the event revealed a step drop of approximately 100 psi occurred when the NISIV was opened. This was sufficient for the rate compensated circuit to generate a safety injection actuation signal, in addition to the SI, reactor trip, feedwater isolation, main steam isolation, and phase " A" containment isolation signals were also generated. Equipment responced as required for these signals. Operations personnel performed the appropriate Emergency Operating Procedures. The SI, feedwater isolation, main steam isolation, and phase " A" containment isolation signals were all reset, and the plant was stabilized in hiode 3 at 2217 hours. , The root cause of this event was procedural inadequacy. Inadequate guidance was given to the operators on avoiding an SI while opening an N1SIV. To prevent this from recurrmg, procedure changes have been processed to provide specific prerequisites for opening an NISIV. This report also fulfills the reporting requirements of Technical Specification 3.5.2 and 6.9.2. s l' R orm 366

1 F, u.s. NUCLEAR REoVLAToRY CoMM:SSioN APFRovE o rgorm 366A g60-0104 i

               %                                                                             Estimated buroen per response to comply with tNs n                         LICENSEE EVENT REPORT (LER)                                        ;"'*"f*yj" *g,'Q';' g'L6,0 f       f,f',*g g    ,,',"n*,'c'f,,,

TEXT CONTINUATION anc Reports Management Branch m-s3ch U.S. Nuclear Regulatory Commission. Washington De 20566. and to the Paperwork Reduction Project 13160-0104 h office of Management and Bacoet. WasNnoton. De 20603 F ACLrTY NAME (1) DOCKET NUMBER (2) LF A iMABF A r6i PAGE131 YEAR NN

               . Millstone Nuclear Power Station                                                                                                         !

Unit 3 0l 6l 0l 0l ol4 l2 l3 8l9 0] 3l 3 0[0 0l 2 OF 0l3 TEXT (if more space is recairec. use accitronal NRc Form 366A s) (171

1. Descrintion of Event At 2157 hours on December 5,1989, with the plant in Mode 3 (Hot Standbv) 557 degrees

'3 Fahrenheit and 2250 psia, the plant experienced a safety injection on low steamline pressure (rate compensated). The safety injection (SI) occurred when plant operators opened the " A" Main Steam Isolation Valve (MSIV), At the time, level in the " A" steam generator was approximately 40% with a differential pressure across the MSIV of approximately 75 psid. The MSIV Bypass Valve was open, The "A" steam generator atmospheric dump valve was open to maintain Reactor Coolant System (RCS) temperature. Strip chart recorders in the Control Room indicated a pressure drop of approximately 100 psi (from approximately 1060 psig to 960 psig) occurred when the MSIV was opened. This was sufficient to generate a steamline pressure low (660 psig setpoint, rate compensated) St. Both charging pumps started and aligned to inject from the Refuehng Water Storage Tank to the vessel. Approximately 500 gallons of water was injected before the S1 was terminated. Both high pressure safety injection pumps and both low pressure safety injection pumps started, but injected no water due to the pressure in the Reactor Coolant System being above the shutoff head of the pumps.

In addition, the low steamline pressure Si also generated a reactor trip signal, a feedwater isolation signal, a main steam isolation signal, and a phase " A" Containment isolation signal. The reactor tnp breakers opened on receipt of the reactor trip signal. All control rods were already at the , bottom. The " A" MSIV closed in response to the main steam isolation signal, as did the four j MSIV Bypass Valves. The remaining three MSI\"s were already closed. The four feedwater . containment isolation valves closed on receipt of the feedwater isolation signal. The feedwater regulating valves and the bypass valves were closed at the time the feedwater isolation signal was generated. All containment isolation valves closed in response to the phase " A" containment isolation signal. Operators followed the applicable Emergency Operating Procedures in response to the St. The SI, feedwater isolation, main steam isolation, and phase " A" containment isolation signals were all reset, and the plant was stabilized in Mode 3 at approximately 2217 hours. II. Cause of Event The root cause of this event was procedural inadequacy. A caution in Operating Procedure OP 3316A " Main Steam System", varns the operators that a feedwater isolation may occur when an MSIV is opened. No warning is given for the possibihty of an SI occurring. Three suggestions are given in this caution for reducing the possibility of a feedwater isolation occurring: reducing steam generator level to 40% - 45%. reducing differential pressure across the valve to less than 25 psid, and/or opening two or more MSIV's simultaneously. None of these three were expressly required prior to opening the MSIV. In addition, there was a contradiction between the recommended (25 psid) differential pressure across the MSIV contained in the procedure caution, and the(100 psid) differential pressure required in the procedure step. Following any one of the recommendations in the caution would prevent a feedwater isolation, but not necessarily an SI. Normal operating practice has been to open at least two MSI\"s simultaneously. This has been sufficient to prevent an SI, but was not required by the procedure. l l NRc Form 366A (6-891

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         .F       orm 366A                       U.6; NUCLEAR REGULATORY CoMMSStoN                      QPOROV      oBN         50-0104
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ment TEXT CONTINUATION ip-r,3on u s. Nuclear Regulatory Commission Wasnmpton. DO 20555 anc to the Paperwork Reduction Pro 3ect (3150-01D4L Office of , 1 Management and Buopet. Vyasnmoton. DC 20503 j F ACILITY f DAME (1) DQcKET NUMBER (2) L E A NUMBE A (fu FAGE(3)  ! YEAR EN hillistone Nuclear Power Station Unit 3 ~ ~ OF 0l 6l 0l 0l 0l4 l2 l3 8l9 0l 3l 3 0l0 0l 3 0l3 TEXT of more space is rewrea use aoartionai NRc Form 3 sex si im

             '111.       'Anahsic of Event                                                                                                                   [

l This event is being reported under 10CFR50.73(a)(2)(iv), an event that resulted in automatic actuation of an Engineered Safety Feature (ESF). This LER aho satisfies the reporting requirement for a special report required by Technical Specification 3.5.2 and 6.9.2. Immediate notifications were made under 10CFR50.72(b)(1)(iv), an esent that resulted in Emergency Core 4 Cooling System (ECCS) discharge into the Reactor Coolant System as a result of a valid signal. l The steamline pressure low Sl is an anticipatory signal designed to mitigate the consequences of a steam line break. A review of the " A" steam generator pressure recorder showed that pressure ]i took a step drop of approximately 100 psi (from approximately 1060 psig to 960 psig) when the htSIY opened. This pressure drop was sensed by all three channels of steam generator pressure. Even though steam generator pressure was still well above the Si setpoint of 660 psig, a rate compensate circuit generated the SI signal in anticipation of the setpoint being reached. j i This is the tenth safety injection that has occurred since the plant was licensed for operation. Five i of these SI's have occurred with the plant in hiode 3, one with the plant in hiode 4, three in f Alode 5, and one, a partial SI, in hiode 1. All but one resuhed in flow to the reactor vessel. These ten actuation cycles are well below the design number of 29. All safety injection nozzle 1; usage factors are below .70. 0 The information contained here on the number of actuation cycles and usage factors is recjuired to 'l be reported in a Special Report within 90 days by Technical Snecification 3.5.2 " Action b , and Technical Specification 3.5.3 " Action c" This information has not been submitted in previous LER's on safety injection actuations, or in a Special Report subsequent to the LER. The root l cause of the faihire to fulfill this reporting requirement is personnel error. While personnel  ! responsible for writing previous LER's were cognizant of the need to report the event under l 10CFR50.73(a)(2)(iv), the Technical Specification reporting requirement was overlooked. To _! prevent this from recurring, this LER has been discussed with appropriate Engineering personnel. The need to include the information required by plant Technical Specifications in future LER's on i this subject was emphasized. i All equipment performed as designed in response to all safeguard signals generated during this '- event. Also, the plant responded as designed to the initiating event. Therefore, this event posed  ! no threat to public health and safety, j

            'IV.          Corrective Action                                                                                                                  {

q The immediate corrective action in response to the SI was to perform Emergency Operatmg Procedure E-0. The Si signal was reset approximately four and a half minutes after it was received. The plant was stabilized in hiode 3 approximately 20 minutes after the SI occurred. To prevent this from recurring, the caution in OP 3316A has been changed to include a warning that an Si could also occur when opening an h1SIV. In addition, the recommendations included in the caution to reduce level, reduce differential pressure, and open at least two SISIV's simultaneously have been written mto the procedure step for opening an N1SIV. Other procedures that operate NISIV's, Atmospheric Dump Valves or steam dump valves have been reviewed and specific requirements put in to prevent a safety injection from occurring when these valves are operated. V. Additional Information There have been no other safety injections on low steamline pressure (rate compensated) due to procedural inadequacy. EllR Codes Sv<tems Comnonents SB-N1ain/ Reheat Steam System ISV - Valve. Isolation NRC Form 366A ($-89)}}