View source for 05000368/LER-1985-022, Corrects 851106 Ltr Forwarding LER 85-022-00.Unit,docket & License Number Incorrectly Listed on Cover Ltr 2CAN118503

{{Adams
| number = ML20138P829
| issue date = 12/12/1985
| title = Corrects 851106 Ltr Forwarding LER 85-022-00.Unit,docket & License Number Incorrectly Listed on Cover Ltr 2CAN118503
| author name = Enos J
| author affiliation = ARKANSAS POWER &amp; LIGHT CO.
| addressee name = 
| addressee affiliation = NRC OFFICE OF ADMINISTRATION (ADM)
| docket = 05000368
| license number = 
| contact person = 
| document report number = 2CAN128505, NUDOCS 8512260284
| document type = CORRESPONDENCE-LETTERS, INCOMING CORRESPONDENCE, UTILITY TO NRC
| page count = 1
}}
{{LER
| Title = Corrects 851106 Ltr Forwarding LER 85-022-00.Unit,docket & License Number Incorrectly Listed on Cover Ltr 2CAN118503
| Plant = 
| Reporting criterion = 
| Power level = 
| Mode = 
| Docket = 05000368
| LER year = 2085
| LER number = 22
| LER revision = 
| Event date = 
| Report date = 
| ENS = 
| abstract = 
}}

=text=
{{#Wiki_filter:_ _ _ _ _ _ _ _ - _   . _ . _____ ___ __ ______ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
ARKANSAS POWER & LIGHT COMPANY l
POST OFFICE 80X 551 UTTLE ROCK, ARKANSAS 72203 (501)3714000 December 12, 1985 2CAN128505 U. S. Nuclear Regulatory Commission Document Control Desk Washington, D.C. 20555

==Subject:==
Arkansas Nuclear One - Unit 2 Docket No. 50-368 License No NPF-6 Licensee Event Report No. 85-022-00 Gentlemen:
In accordance with 10CFR50.73(a)(2)(iv), attached is the subject report r;nncerning a reactor trip on high steam generator level due to closure of the 'B' main feedwater regulating valve.
This letter corrects a typographic error in the letter 2CAN118503 dated November 6, 1985. The unit, docket and license nun.bers were incorrectly listed on the cover letter. A copy of the original letter and licensee event report are attached.
(
Very truly yours,
                                                    /               J. Ted Enos
(                Manager, Licensing JTE:RJS;1w Attachment cc:   Mr. James M. Taylor Office of Inspection and Er forcement U. S. Nuclear Regulatory Commission Washington, DC 20555 0512260204 051212 f'Dft U
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NRC Form 366                                                                                    U.S. Nuclear Regulatory Commistfon (9 83)                                                                                                 Approved OM8 No. 3150-0104 Expires: 8/31/85 LICEN5EE               EVENf       REPORT           (L E R)
FACILITY NAME (1) Arkansas Nuclear One, Unit Two IDOCKET NukBER (2) IPAGE (3) 1015!0l0101 31 61 81110Fl012 TITLE (4)            Reactor Trip on High 5 team Generator Level Oue to Closure of Main Feedwater Regulating valve
              ~ EVENT DATE (5)                  leo NuM8ER (6)                 REPORT OATE (7)           OTHER FACILITIE5 INVOLVED (8) l     l               l 15equentiall l Revision              i     i Monthi Day lYear                                                                                                 i Year i i Number ! l Number l Month [ Osy lYear i                 Facility Nsmes          lDocket Number (s) i     l               i i              i i            l      I     I      i                             1015 olo 0 11 01 01 81 al 51 81 Slal 01 21 21 - 1 0l of 11 11 Of 61 81 St                                                 1015 010 0 6PERATING l ITHIS REPORT 15 $UBMIITED PURSUANT TO THE REQUIREMENTS OF 10 CFR 5:
MODE (9)           11 (Check one or more of the follow 8no) (11)
F6WER)           ,,,,i 20.402(b)             l_l 20.405(c)                  lJ) 50.73(a)(2)(tv)         l_l 73.71(b)
LEVELI         i
_l 20.405(a)(1)(1)          l _l 50.36(c)(1)               l l 50.73(a)(2)(v)          l_I 73.71(c)
(10) 1019181 l 20.405(a)(1)(if)              1.,,,,1 50. 36(c )( 2)         l __ l 50.73(a)(2)(vii)     l_I Other (Specify in l_l 20.405(a)(1)(Ill)         l_l 50. 73(a)(2)(1)           l_l 50.73(a)(2)(vfil)(A)l          Abstract below and l _t 20.405(a)(1)(iv)         l_ l 53.73(a)(2)(11)           l                                 in Text, NRC Form i l 20.405(4)(1)(v)           l l 50.73(a)(2)(fit)          I _li 50.73(4)(2)(x) 50.73(a)(2)(vift)(8)l  1     366A)
LICENSEE CONTACT FOR THIS LER (12)
Name l _ Telephone Number 0 wight J. Johnson, Plant Licensing Engineer                                          IArea l ICode i 1510111916l41 13111010 COMPLETE ONE LINE FOR EACH COMPONENT FAILURE DESCRIBED IN THIS REPORT (I))
l         l              l             lReportablel           l     1         l             l             l Reportable   i Cause System l Component Manufacturerl to NPR05 l                    ICausel5ysteml Component IManufacturer to NPRD5 i                            l              l       I     i         l             l W     5t J     Fi Cl VI      Fl 11 31 Of               Yi       f     I l          i I I I l l l I              i       l     I                      i                           i I   L I I l I I l                l.             I       I     I I        l I l l I I I I           I             f i
f 50PPLEMEN ' REPORT U PECTED (14)                                                            Day      w ear l EAPECTED i Month                      ;
               ~
l $UBMI55!0N l ~
Ye ejf f a   os~omplete c         Espected Submission Date) IIll No                               l DATE (15) I       l     I I
I           I( m t to 1400 spaces, i.e. , approximately fif teen single space typewritten lines) (16)
On 10/8/85 at 1051 hours with the unit operating at 98% power the reactor was automatically tripped on high steam generator level based on 'B' and 'O' channels of the Reactor Protective System (RPS) receiving an Indicated ' A' steam generator level 193.44 (trip setpoint). The RP5 actuated on the 2 out of 4 channel trip logic to trip the reacter. Post trfp pressures and temperatures responded as espected the high steam generator level cleared when                            i the reactor was shut down, and emergency feedwater actuated as antic} pated to restore normal steam generator levels. The plant was stabilfred in hot standby (Mode 3) conditions. The cause of the high level in the 'A' steam generator was the closure of the '8' Main Feedwater Regulating Valve (MFRV) which caused an increase in main feedwater pump speed demand on both main feedwater pumps. This increase in pump speed caused a large feed flow / steam flow mismatch in the ' A' steam gerarator which was not adequately of f set by closure of the ' A' MFRV in i
time to prevent reaching the high level trip setpoint in the ' A' steam generator. The closure of the 'B' MfRV was due to desiccant carryover from the instrument air dryers foulfng the pneumatic relays in the '8' MFRV electro pneumatic valve positioner. Corrective actions to prevent recurrence have included installation of a 1 micron duples filter in the instrument air supply to the MFRVs, increased preventive maintenance in this area, and inspettlon of the Instrument air drying towers retention elements. A similar event was described in LER 50-368/84 014.
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I Form 1062.01B NRC Form 366A                                                                      U.S. Nuclear Regulatory Commission (9-83)                                                                                      Approved OMB No. 3150-0104 Expires: 8/31/85 LICENSEE EVENT REPORT (LER) TEXT CONTINUATION FACILIfY NAME (1)                                     100CKLI hUMBER (2) i            LER NUMBER (6)         l PAGE (3) l                  l       l lSequentfall lRevisioni Arkansas Nuclear One, Unit Two                        l                  l_ Year     l Number ! l Number l fol5101010f 31 61 al 81 5   --!   01 21 21- i 01     Ol0l210Fl012 TEXT (If more space Is required, use additional NRC f orm 366A's) (11)
On 10/8/85 at 1051 hours with the unit operating at 98% power the reactor was automatically tripped on high steam generator level in the 'A' steam generator. The trip was initiated by the receipt in the
                                                                                                          'B' and 'D' channels of the Reactor Protective System (RPS) of ' A' steam generator level greater then 93.4L This condition resulted in the necessary 2 out of 4 channel trip configuration required for RPS actuation (a reactor trip). Post trip res1onse was normal and the high level condition was mitigated by steam generator and main feedwater control system reaction to the unit trip. No abnormal conditions were noted during the post trip period and the unit was stabillied in Mode 3 conditions with the reactor coolant system at 2250 psia and 545'F.
The cause of the high 'A' steam generator level was an over feeding condition that resulted from the closure of the 'B' Main Feedwater Regulating Valve (MFRV), 2CV 0740 (IEES Identifier = 025J FCV 0740) for the 'B' steam generator. When the 'B' MFRV closed the B main feedwater control system sensed the decrease in feedwater flow to the 'B' steam generator and increased the 'B' main feedwater pump speed to compensate. This increase in pump speed demand on the 'B' main feedwater pump was transmitted to the ' A' main feedwater control system which, through a high select circuit, resulted in the equivalent speed demand being placed on the ' A' main feedwater pump. This resulted in a large steam flow / feed flow mismatch on the 'A' steam generator and the high level trip setpoint was reached before the 'A' MFRV could respond to mitigate the high flow condition. The high level in the ' A' steam gererator was terminated when the reactor tripped due to normal steam generator level response (shrink ef fect) and the designed response of the main feedwater control system.
The shrink effect in steam generator level induced by the reactor trip initiated emergency feedwater actuation based on low steam generator level in the 'B' steam generator. Both emergency feedwater pumps and valve trains responded as required to the transient. At 1109, 10/8/85, the steam driven emergency feedwater pump (ZP 7A) was secured per Emergency Operating Procedure recovery actions. Normal steam generator levels were subsequently restored and maintained.
The cause of the 'B' MFRV closure has been identified as an accumulation of desiccant in the valve actuator assembly from the instrument air system dryers. This accumulation of desiccant restricted operation of pneumatic relays which allowed the valve to close. Both MFRVs are electro pneumatically positioned valves with pneumatic operators which are supplied with air from the plant instrument air system. The plant instrument air system supplies dry, oil free pressurtred air to a variety of plant systems. The compressed air is maintained dry by the use of drying towers which contain a desiccant. Over the operating Ilfe of this system the desiccast has broken down somewhat and ultra fine particles have apparently contaminated portions of the system, despite the presence of 40 micron primary filtering units in this system. No safety related components that utfllte instrument air have been af fected by desfecant contamination.
Corrective actions were initiated 10/8/85 at 1400 hours to replace the pneumatic relays and readjust the valve positioner on the 'B' Mf RV. The 'A' MFRV was stroke tested satisfactorily for response performance. This work was completed 10/8/85 at 1615 hours. The plant was subsequently returned to power operations. Additional corrective actions include the installation of 1 micron duplea filters in the Instrument air supply line to the MFRV's and an increase in preventive maintenance associated with this portion of the main feedwater control system. Also, work was completed on inspection and repair of the instrument air drying tower retention elements.
A study of potential long term solutions has been initiated by the maintenance, engineering, and operation groups to identify feasible future courses of action if any are necessary. A siellar event was described in LER 50 368/84 014.
l                                                         .
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                                                                                      ~
ARKANSAS POWER & LIGHT COMPANY POST OFFICE DOX 551 LITTLE ROCK. ARKANSAS 72203 (501)3714000 November 6, 1985 2CAN118503 U. S. Nuclear Regulatory Commission Document Control Desk Washington, D.C. 20555

==Subject:==
Arkansas Nuclear One - Unit 1 Docket No. 50-313 License No. OPR-51 Licensee Event Report No. 85-022-00 Gentlemen:
In accordance with 10CFR50.73(a)(2)(iv), attached is the subject report concerning a reactor trip on high steam generator level due to closure of the 'B' main feedwater regulating valvo.
             .                                               Very truly yours, 65D-J. Ted Enos flanager, Licensing JTE:RJS:1w Attachment cc:   ltr. James M. Taylor Office of Inspection and Enforcement U. S. Nuclear Regulatory Commission Washington, DC 20555
                         . VE VOt f1 M'004 t" ficu f te t;f esitet s O v s t r u

I
* ERC Fcro 366 (9 83)
U.S. Nuclear Regulatory Commission Approved CHa No. 3150 0104 1!CEN$EE EVEHT REPOR1                                                                            Espires: 8/31/85 (L E R)
FACILITY NAME (1) Arkansas Nuclear One, Unit Iwo TIILE (4)                                                                                                                         IDOUEI NUMBER (2) IPAGE (3)
Reactor Trip on Hign Steam Generator Level Oue to Closure of Main                                                         ng valvef eeowater R
_ EVENT DATE (5) i           i                       (ER NUM8ER (6) l 15equentiell (Revision REPORT                   DATE (1)       t I         l                  OTHER FAtlLillE5 INVOLVEL (ff)
Month)    l     Day  J lYear J
lYear     I i  Number        i i Number        IMonthi         Day lYearFacility i        Names l
( l                  i l            I          I        i                                                ' Docket Number (s) ~~
110101818f$l8I$l-l 6PERAllNG           l                        of 21 21 - 1 01                0111!!0161At51 l_
015 010j04
* i ~
llIIH15 REPORT 15 $U8HITTE0 PUR50ANI 10 ThE 015 010101 i i N00E (9)            I                                                                                                 REQUIREMLNIS 10 CFR   O                             Of P0wERI              l           (Check one or more I 20.401(o)                     l of the fo)1owinn) (11)
LEVEll l_l 20.405(4)(1)(t)                    l _l 20.405(c)                        IJi 50.H(4)(2)(iv)                  l_t D. 7)(b)
(10) 101918'_I 20.405(a)(1)(tt) l_ l) 50.36(c)(1) 50,36(c)(2)                    l t 50.73(a)(2)(v)                   l
_l 20.405(a)(1)((H) I _1 50.73(a)(2)(1)                                    l_I 50. 73(a)(2)(vil)               ( _IOther 73.71(c) l__l  50. D(a)(2)(vif      t)(All_l               ($peelfy in ILl20.405(4)(1)(iv) i 20,405(4)(1)(v)                 li l_~1 50.73(a)(2)(ll)                  l_l  50.D(a)(2)(vHt)(8)1 Abstract below and in Test, hRC Form
: 50. 73(a )[2 )( I t i )       I I 50. D(a)(2)(s)
Name                                                                                                                                 i       3664)
(ICENsEE~CONIACI FOR THIS LER (12)
Dwight J. Johnson, Plant Licensing Engineer                                                                   1 Te)ephone Nomoer
          .                                                                                                                                               IArea i ICode i l
Causel$vstem l
COMPLETE t                     ONt ((NE FOR (Reportablel             I      EACH i          l COMPONENT FAILORE DE5CRIB                               ~
(
Component lHenufacturert to NPRDS l ..                                                           l                   lHeportaolet (Cautel5ystemi Corponent (Manuf acturert to NPcOS 11  ' $1 J F1 Cl VI il FI 11 3I OfI                                   i          i       )          l                i Yi          i        i i                                              i I
I                  I              i          i        i I i i l 1 I I I I i
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                                                      $UPPt(HENI REPORT E WEC1ED (14)                                   I I I I i i t i                      1              1 i E p ECIED L Hont h              Day   rese h Yes (If yes. complete Evoected Submission Date)                                 III No                                 l $UCMIS$10M i IB5IIICI (Limit to 1400 spaces,                                                                                            I DATE t.e., approntmately fif teen single space typewritten                         li (15) I          i )    i I I nes) (16)
On 10/8/85 generater        level based    at 1051on '8' hours and 'D' with the unit operating at 98% power the                                                 reactor was autoritica y tripped on hign steam steam       generator            level }93.4%      (trip    channels of the Reactor Protective $ystem (RP)) receivi setpoint).                                                                           ng an indicated 'A' reactor.
the reactor levels.
Post            trip pressures and temperatures responded as espected, the high steam was shut down, and emergency feedwater actuated as anticipated to rest                                             r level cleared when i
The plant was stab (11 ed in hot standby (Mode 3) conditions.                                                   ore normal steam generator steam main     feedwatergenerator       pump speed wasdemand the closure on both main of the         '8' Main feedwater         pumps. feedwater               Regulating          a e in Valve (MFR time to prevent reaching                                   steam generator the high        which  levelwas not tripadequately setpoint        of f set in bThis y Closure       the     'incrosse of the 'A  A'MFRVsteam in pun.p ges in was due electro             to desiccant pneumatic                           carryover valve positioner.               from the instrument air dryers foulingays               .
the     pneumatic relThe closu in the 'B' MTRV micron duples filter in the instrument air supply to the MFRVs, increased preventhe 50 368/84 014.and inspection of the instrument air drying towers retention e)ements nce in this area, A similar event was described in LlR l
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NRC Faro 366A                                                                                                    fora 1062.018 (9 83)                                                                                     U.S. Nuclear Regulatory Commission Approved OM8 No. 3150 0104 Empires: 8/31/85 tlCEN5([ [ VENT REPORT (LER) T[XT CONTINUAi!0N FACILIIV NAHf. (1)
  .                                                                      lDOCM I NUMBER (2) l            ttR NUMBER (6)
Arkansas Nuclear One, tinit Two                               l                                                            l PAGE (3)-
l l      l 15equentiall l Revision l I Yearl        Number l       Number I f ol51010101 31 61 81 el 5 --      06 26 21--
TEXI (If more space is required, use additional NRC Form 366A's) (17)                                            01      Ol0l210Flil2 On 10/8/85 generator    level at  1051 in the    'A' hours    with the unit operating at 984 power the reactor was automatically tripp steam generator.
the Reactor Protective System (RPS) of 'A' steam generator level greater then 93.4LThe                         and 'O' tripchannels was initiated of       by th the necessary 2 out of 4 channel trip configuration required for RPS actuation (a reactor                        ,
Posttrip)This tric      condition re system reactica to the unit trip. response was normal and the hign level condition was mitigated by steam ge stabilized in Mode 3 conditions with the reactor coolant system at 2250 psia and 545'f.No abnorm The cause of the high 'A' the                              steam generator level was an over feeding condition that resulted from the closure of
                'B' Main generator.        Feedwater When  the          Regulating Valve (MFRV), 2CV 07a0 (IEES Identif ter a 025J FCVsteam                          0740) for the '8' the   'B'                  'O' HFRV closed the 8 main feedwater control systee sensed the decrease in feedwater flow steamon speed demand      generator the        and increased the '8' main feed.ater pump speed to compensate          .
                                    '8' main feedwater pump was transmitted to the ' A' main feedwater control system which, through a high select circuit, resulted in the equivalent speed demand being placed on the pump,
                    'A' main feeddsterihls resulted in a large steam flow / feed flow mismatch on the setpoint was reached before the 'A'                                                'A' steam generator and the high level trlp MFRV could respond to mitigate the high      flow condition. The high level in (shrink     steam    generator effect)       andwas  theterminated designed    when     the reactor of response        tripped theduemain to normal     steam generator feedwater           controllevel     respon system.
steam based          generator.The on low   steam generator level  shrink       effect in steam gener4 tor level induced by the in the 'B'                                                                               reactor trfp responded as required to the transient. At 1109, 10/8/85,                    Both emergency feedwater pumps and valve trains secured per [mergency Operating Procedure recovery actions. the steam driven emergency feedwater pump (27 7A) was restored and maintained.                                                   Normal steam generator levels were subsequently assembly from the instrument air system dryers.The cause of the 'B' Nf RV closure has bee relays which allowed the valve to class.                     This accumulation of desiccant restrfeted operation of pneumatic operators which are supplied with air from the plant instrument                                  air system.Both Mf 4Vs are electro pn The plant instrument air system supplies dry, oil free pressurlied air to a variety of plant systems.
the use of drying towers which contain a destccant.                                   The compressed air is maintained dry by Over the operating Ilfe of this system the desiccant has brosen down presence                somewhat of 40 micron    primary and    ultraunits filtering    fineinparticles this system.have apparently contaminated portions of the system, de instrument air have been af fected by desiccant contamination. No safety related components that utillte
      '8' HFRV.onCorrective positioner          the            actions The 'A' were initiated 10/A/85 at 1400 hours to replace the pneumatic relays and rea was completed 10/8/85 at 1615 hours, HFRV was stroke tested satisfactorily for response performance. This work the plant was sut,sequently returned to power operations. Additional HFRV's system.             and an increase in preventive milntenance associated with this portion Also, work was completed on inspection and repair of the in;trument air drying tower retention elements A study of potential long term solutions has been initiated tiy the maintenance, engineering, and ope                                    .
to 50 it4    identify 36A/84feasible 014     future courses of action if any are necessary. A similar event was described in
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