ML20246C224

AEOD/T909, Operating Events Involving Dampers

ML20246C224
Person / Time
Issue date:	05/30/1989
From:	Israel S NRC OFFICE FOR ANALYSIS & EVALUATION OF OPERATIONAL DATA (AEOD)
To:
Shared Package
ML20245B669	List: ML20245B667 ML20246C224
References
TASK-AE, TASK-T909 AEOD-T909, NUDOCS 8907100294
Download: ML20246C224 (13)

Text

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. AE00TECHNICALREVIEWREPdRT  !

UNIT: N/A TR REPORT NO.: AE00/T909 l DOCKET NO : N/A DATE: May 30, 1989 -

LICENSEE: N/A EVALUATOR / CONTACT: S. Israel

SUBJECT:

OPERATING EVENTS INVOLVING DAMPERS SU!EARY l

t About 130 documents en damper failures were collected for the period 1986 to  !

the present. This database indicated that about 40 percent of the problems occurred in fire barrier u mpers and the major contributor to these failures is ,

the inability to close under design air flow conditions. To a lesser extent,.

damper failures also occurred in control room ventilation systems and were caused by design and operational deficiencies. NRR has ongoing activities to develop generic co munications that would address these problems.

l DISCUSSION

1. Background During the normal LER screening process, events related to dampers in fire control areas and ventilating systems seemed to be occurring regularly. .

Damper concerns were also highlighted by a recent AE00 study on emergency j ventilation systems for control rooms (Ref.1). A search of the Nuclear '

Documents System (NUDOCS) was performed to identify reported activities on  ! i this subject for 1986 to the present. About 250 documents were found that had the word damper or dampers in the title or text as appropriate. These were examined and reduced to about 130 independent reports of problems with dampers, i A list of the relevant documents is preser.ted in the appendix for future  !

reference. l

2. Analys',s of Events About 40 percent of the events involve fire barrier darpers while the reraining damper refersi:;es are fairly well distributed among the ventilation systems for the control room, containment, diesel generator building, auxiliary build!ng, and others. Activity associated with Appendix R reviews in the early 1980s was probably responsible Ier identifying many of the flaws with firo carriers. The fire ventilation damper is generally a curtain type with a fusible link that is heat sensitive. Upon actuation, the pleated damper falls into place by gravity I or is spring assisted.

A variety of dampers are used in ventilation systems to modulate or isolate the air flow. These include louvered, butterfly, blade, and bladder types.

The ventilation dampers may oe air actuated or motor driven. Activity related j to control room habitability may have uncovered some of the problems with these l' 1 systems.

8907100294 090530 PDR ORG NEXD

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O- About half of the damper failures were initiated by deficiencies in design, fabrication, and installation. Two other failure contributors of interest l Q y were mispositioned damper events and failure of the damper actuator. .Each account for about 10 percent of the events. Specific flaws in the design, 4 fabrication and installation category include inability to close under design j 1 air flow conditions, mechanical interferences to damper movement, and single 4 failures. )

The inability of fire dampers to close under design air flow conditions was

?/f identified in November 1984 and was the subject of a part 21 notification by d

the manufacturer and several licensees. This problem was the cause of most of the fire damper reports. Region III and Office of Inspection and Enforcement

,. developed drafts of information notices on this problem in 1986 because they J discovered that similar dampers from other manufacturers also had this problem.

Apparently, the original tests by manufacturers did not simulate actual installa-A( tion conditions. TheOfficeofNuclearReactorRegulation(NRR)isstill

@ working on an information notice delineating the inadequacies in fire damper y designs / applications and inadequacies in surveillance tests at the plants.

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Damper installation problems included interferences that precluded complete )

closure of the damper, upside-down installation, installation in the middle of (

? the duct instead of at the wall, and not installed at all. Single failure problems occurred in ventilation systems and were discussed in Ref.1. These included singularities in control systems and absence of backdraft dampers to preclude backflow through an idle loop. These types of problems occurred at old plants as well as newer plants.

A number of the events were concerned with mispositioned dampers. These generally resulted from poor administrative control of the ventilation system configuration or were the result of trying to correct overall system response '

during a surveillance test. Some of these events occurred during maintenance activities when portions of the ventilation system were defeated to accomplish a particular task or degraded by running electric cabling through the ductwork and the dampers needed for isolation purposes.

Several events were concerned with the failure of the damper actuators, particularly solenoid valves. This issue of solenoid valve failures is the subject of a separate ongoing AEOD study. A generic cocronication was trans-mitted to the utilities regarding problems with ventilation for the diesel generator rooms (Ref. 2) caused by deficient design of the damper actuation.

Safety implications of deficiencies in fire dampers are significant because of potential loss of both trains of one or more vital systems. The actual impact will vary from plant to plant depending on the amount of communication between vital areas and the amount of totally separated backup equipment available to maintain the plant in a safe configuration. Problems with isolation dampers t in the control room emergency ventilation system could be significant because toxic gas accidents may not provide sufficient warning to correct problems manually.

Periodic surveillance is performed on the fire dampers usually on an 18 month interval. There is a lack of uniformity in the type of test (static or dynamic) and some plants perform the tests on a sample of the dampers in the

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w W y-p:;' 4 p plant. Experience has indicated that not all the failures are reportable in LERs or reported in NPRDS. Consequently, the references in the appendix may r, ";,

not reflect the true magnitude of the problem. Dampers in emergency ventilation

, systems are tested as part of an integrated systems test on an 18 month interval.

Because the systems test is concerned with positive pressure in the control room and the damper positions are not monitored, problems with dampers could

[, go undetected.

E Initiatives are already underway in NRR to address most of the problems observed e in fire barrier dampers and ventilation dampers. In particular, a new informa-p tion notice is being drafted to inform the utilities of the problems with fire dampers. This effort is scheduled for completion in September 1989. Dampers in centrol room emergency ventilation systems are being addressed indirectly in pl. a generic letter being developed by NRR addressing the system perfonnance and 0" the surveillance procedures.

CONCLUSION r

b Although problems with dampers persist, there are already mechanisms in place to monitor these components and the NRC has ongoing initiat'.yes to enhance the existing surveillance procedures to capture deficient dampers and to inform the utilities regarding specific flaws observed.

REFERENCES

1. S. Israel, Design and Operating Deficiencies in Control Room Emergency Ventilation Systems, AE0D Report AEOD/E802, April 1988.

2. U.S. Nuclear Regulatory Comission, Office of Inspection and Enforcement, Emergency Diesel Generator Room Cooling ' Design Deficiency, IE Information Notice No. 87-09, February 1987.

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', APPENDIX {

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DAMPER SEARCH IN NUDOCS 1986 4-

, NOTE Each entry is a truncated form of the title as it 1: . appears in the NUDOCS search format. The microfiche lj number is on the left side and the NRC accession number

's is in the upper lef t corner of each entry.

n l? 8605140173 05000295 35987 LER 86-014-00: on 860408, auxiliary b1dg supply fan outlet 145 damper found failed open w/ fan off. Caused by turning 8605140177 05000295 35989 LER 86-005-00:en 860410, discovered that outlet dampers for 004 cribhouse svc water area ventilation fans CBS & OCS i 8601230424 05000482 34335 LER 85-086-00:on 851220, discovered that required fire 211 dampers not installed in ventilation penetrations 8601240191 05000443 05000444 34359 Interim Potential Part 21 & Deficiency Rept CDR 85-00-20 264 failure of fire damper to close under design airflow 8601300129 05000259 05000260 05000296 34414 Discusses apparent discrepancy between actual plant design 160 FSAR re closure times of various secondary containment 8602060393 05000293 34488 LER 85-034-00:on 851231 discovered that 21 fire dampers 256 required by Tech Specs found degraded.

8603120452 05000346 34926 LER 86-010-00:en 860121.during informal walkdown, discovered 173 that 21 fire dampers not properly installed. Caused b 8604090265 05000295 35499 LER 86-009-00:en 860303, vent fan outlet damper for ID 1 156 diesel generator room failed to close upon receiving '

8604100192 05000295 35501 LER 86-010-00:on 860303. observed that outlet damper for OAS 046 ventilation fan for cribhouse svc water pump area 8604210289 05000368 35666 LER 86-003-00:on 860312 & 13, fire dampers 2FD-2123-33 &

098 2FD-2198-9 failed to close during testing.

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t l:: 8604250263 05000388 35705 LER 86-005-00:en 860321 differential pressure condition ,

i 352 detected, causing supply dampers to oscillate.

i 8605190235 05000312 1

' 36012 Special Rept 86-07: updating 860320 Special Rept 86-04, 326 listing nonfunctional fire barriers.  !

8605190377 05000305 36014 LER 88-004-00:on 860401,nonspring-assisted fire dampers 139 mechanically bound in intermediate position.

8605230338 05000346 36079 LER 86-019-00:en 860417, testing revealed that ventilation 247 sys damper controller failures caused facility to 8606020058 05000368 i 36160 LER 86-016-01:en 840621, penetration fire barrier dampers 1 005 failed to completely close when fusible link removed 8606110194 05000424 05000425  !

36368 Forwards detailed info re fire damper installation i 216 deviations, test program conducted at UL & evaluation 2 8606110501 05000438 05000439 36428 Final Part 21 & deficiency rept re Ruskin fire damper 277 installation & closure problems. Initially reported i 8606200429 05000336 36640 LER 86-003-00:en 860516, evaluation of fire dampers in 044 response to IE Info Notice 83-69 defined 20 fire dampers 8606230504 05000443 05000444 36654 Final Deficiency Rept (CDR 85-00-16) re gauled threads on 198 manual handwheel operators on safety-related dampers ,

8606250194 05000364 36703 LER 86-006-00:en 860521,during heatup after maint outage, 117 fire damper in penetration 05-139-06 inoperable due 8607020320 05000321 36847 LER 85-015-01:en 850321, incorrectly wired isolation logic 199 for reactor bidg supply fan discharge inboard isolation 1

8607070299 05000311 36871 Special Rept 86-5:en 860524, fire damper 2CAF207 failed to i 001 close upon receipt of automatic trip signal.

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37065 Interim Deficiency Rept DER 86-20 re damper seals not 306 meeting required specs. Initially reported on 860603.

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8607080392 05000440 36928 LER 86-021-00:on 860602, discovered that five recirculation 212 damper actuators in diesel generator b1dg ventilatio

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', 37081 Insp Repts 50-348/86-11 & 50-364/86-11 on 860514-0610.

{p 021 Violations noted: fire damper inoperablo & procedures r -

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, 37167 Special rept:en 860616, fire dampers VS-D-93,95A & 95B 359 declared inoperable after not fully closing 4-8607280006 05000245 05000336  ;

37251 Discusses results of evaluation,per IE Info Notice 83-69,  ! ;

100 identifying deficiencies in certain fire barriers.

l 8608120438 05000281 37460 LER 85-008-01:en 850619, auxiliary ventilation damper 157 1-VS-HOD-58A drifted closed. Caused by short in 8609030068 05000424 05000425 37712 Final deficiency & Part 21 rept re control room isolation i 135 damper solenoid valves not in conformance w/ design 8609180105 05000483 37890 LER 85-041-01:en 850913,12 dampers identified w/less than i 196 required sleeve-to-damper clearance.

8609230331 05000312 37963 Special Rept 88-14:on 860723, Zone 78 CO2 fire protection sys 153 out of svc for more than 14 days.  !

8609240012 05000312 37969 Special Rept 86-16:en 860804, Zones 12 & 13 CO2 fire 217 protection sys for control room mezzanine level 8611030475 05000285 38448 RO:on 860915,during performance of ST-FP-10, "Halon 035 Surveillance," previously unidentified fire damper 8611050050 05000412 38477 Final Significant Deficiency Rept 86-10 re closure of 280 two American Warming & Ventilation.Inc nonsafety-rel 8611200539 05000295 38667 LER 86-039-00:en 861016, attendant unable to determine 081 prefilter inlet damper PT-19 was open.

8612040242 05000528 05000529 05000530 I 38831 Part 21 & final Deficiency Rept DER 86-20 re Ruskin damper 235 seals not meeting required spees. Initially 8612050305 05000498 05000499 i

38834 Final deficiency rept re safety-related Techno HVAC dampers.

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'41 Initially reported on 861029. Damaged spread pins )

1 8612120338 05000528 l

38949 LER 86-055-01:en 861106. Surveillance Test 36ST-9SAO

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!p TE 8612160363 05000315 39007 LER 86-02f-00:en 861111,w/ reactor at 90% power,ESF q 203 ventilation fans discovered inoperable for approx l'

1987 8701200397 05000327 05000328 39315 Rev 1 to " Fire Protection Design: Lack of Fire Dampers  ;

080 Addl Diesel Generator Bldg," element rept. j 8703170066 05000395 I 40040 Special Rept SPR.87-001:en 870210, discovered 360 seismically unqualified fire damper installed 8702260196 05000445 05000446 39740 Final Deficiency Rept CP-86-75 re ASCO solenoid valves 035 piston air actuators of PAPCO dampers.

8703030031 05000482 39822 Insp Rept 50-482/87-01 on 870101-31. Violation noted: fire 270 damper not operable as required by Tech Spec 3.7.11. -

1 05000344 39873 LER 87-002-00:en 870129, positive pressure could not be  !

200 maintained in control room w/ control room .'

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8703090438 05000373 I 39926 Special rept:en 870129, fire damper found to be installed 246 upside down & declared inoperable.

8703100228 05000482 39938 LER 87-006-00:en 870203, fire damper GKD050 failed to close  !

290 during testing. '

8703200188 05000528 05000529 05000530 40099 Final Part 21 & Deficiency Rept RER-QSE 87-05 re travel 074 limit switches on HVAC dampers.

8704010392 05000461 40313 LER 87-009-00:en 870306, exhaust fan A of fuel b1dg 312 ventilation sys tripped.

8704200282 05000414 40591 LER 87-009-01:en 870312, discovered Unit 2 containment air 350 return isolatier. dampers open. constituting ESF 8704280669 05000321 i 40700 LER 87-005-00:on 870318,one secondary containment .

073 ventilation exhaust damper did not actuate l

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~ r 8705.050388 05000295 40813 LER 87-008-00:en 870401 pneumatic bypass for 1B diesel 163 generator room fan damper removed w/o energizing 8705050377 05000259 40812 LER 87-006-00:on 870302, discovered ~that routine flow rate 004 surveillance on control room emergency ventilation 8705180005 05000414 l 40940 LER 87-015-00:en 870406, containment air return fan B 042 isolation damper unexpectedly opened. constituting i 8706100269 05000285 }

41239 Special rept:on 870501,util informed by Ruskin Hfg that at 174 least two fire dampers installed in EVAC duct 8706100456 05000261 41239 LER 87-006-00:on 870501,while Unit 2 in refuelingshutdown. <

037 diesel generator room damper failure on loss of 8706170179 05000412 41385 Potential Significant Deficiency Rept 87-15 re failure 230 main steam valve area supply fans to start automatic 8706230184 05000529 41427 LER 86-044-00:on 870515. discovered that both independent  :

209 trains of control room essential filtration sys .

8707210818 05000348 l 41828 LER 87-011-00:en 870611,results of testing of fire dampers 273 declared inoperable on 870605, determined that damper 8708100440 05000259 05000260 05000296 42092 Notice of violation from insp on 870601-30. Violation 4

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231 noted: failure to properly disposition significant l 8708100497 05000424 42091 LER 87-044-00:on 870702 & 04. design problem related to ,

324 adequacy of HVAC sys for operation in emergency  ;

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8708110495 05000259 42106 LER 87-014-00:on 870708, control room emergency ventilation 303 sys measured flow rates in excess of design basis 8708140125 05000327 42158 LER 87-039-00:en 870710. potential for single failure of main 127 control room normal pressurization sys observed.

8708180204 05000395 42198 Part 21 rept re design of control room ventilation sys not I 170 in compliance w/sys requirements identified in FSAR ,

8708200058 05000445 05000446 42217 Supplemental Part 21 & Deficiency Rept CP-84-08 re curtain l]I, 269 fire dampers installed w/o specified gap between '

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'D 8708240426 05000348 L; 42314 LER 87-014-00:en 670717, fire damper 1-116-15 in nonradiation p? 157 ventilation sys tested & would not close w/ air ti b 8709150059 05000387 42637 LER 87-025-00:on 870810, reactor bldg heating, ventilating

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6 158 air conditioning Zones I & III discovered cross-tied B709170177 05000425 l 42714 Part 21 & deficiency rept re design of control room y 109 essential (CRE) HVAC sys. Initially reported on 8710090041 05000387 y 42998 LER 87-026-00:en 870SO4, reactor bids HVAC sys Zones I & III

[- 355 discovered to have been cross-tied.

8710070659 05000348 j 42963 LER 87-015-00:en 870831,0914 & 22, control room fire dampers

251 did not close w/ air flow during testing.

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i. 13252 LER 87-069-00:on 870930, unexpected annulus exhaust gas 109 treatment sys Train B auto start following

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1 8710280181 05000285 43192 LER 87-025-00:en 870923, diesel generator 2 automatically

! 181 shutdown due to high coolant temp.

V 8711020486 05000348 43252 LER 87-016-00:en 870917, fire dampers inoperable due l 238 failure to close w/ air flow. .

1 8711090285 05000483 i 43322 Safety Insp Rept 50-483/87-33 on 871007-17. Violations noted: i 171 failure to perform adequate preoperational test 8711130341 05000334 1 43359 LER 87-017-00:en 871009,two damper penetrations found 354 unsealed.Once per hour fire tours of cable tray 8712100239 05000312 l 43718 LER 87-044-00;on 871110. concern raised re potential loss of 1 074 nuclear svc electrical bldg essential HVIC during I 8712290149 05000364 43824 LER 87-007-00:on 871123, fire barrier penetration 03-139-33 263 nonfunctional for more than 7 days.Cause not stated.

8712290432 05000348 43825 LER 87-023-00:on 871127, control room fire dampers inoperable 302 due to failure to close w/ air flow. Caused by design l

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1. - ~ 05000334 hjip0- 44063 Special rept:seven fire. dampers failed to fully close during gj ; 078 operational testing & not restored within 7 days.

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8801140122 05000528 .

44042 LER 87-016-01:on 870609,both trains of ESF' pump room air

'j, 275 exhaust cleanup sys inoperable. caused by personnel-1' s

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/' 44135 LER 87-072-01:en 871110,ESF coolers had insufficient'_ air 041 flow to ensure environ qualification temp profile.no

' 8802020224 05000275 i .

44108 LER 87-028-00:en 871230,both trains of auxiliary b1dg 114 ventilation sys inoperable in violation of Tech 8802030158 05000285  !

- 44223 Followup to special rept on inoperability of fire barrier. l T 126 During Sept 1986,util discovered that fire damper F1 I.8802080160' 05000352 F 44272 LER-87-070-00:en 871231, reactor enc 1 isolation on low

.. 206 differential _ pressure occurred. Caused by air leaking n

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[, 44307 LER 87-063-01:en 871218, discovered that inlet isolation L. 344 ~ damper for plenum "OC" closed but operable during k

8802120173 05000305 44341 LER 87-012-00:en 871128,two independent containment 162 isolation control valves failed to close from CR 8802220033 05000364 44463 LER 88-001-00:en 880111. discovered control room fire damper 204 inoperable. Caused by design deficiency.

8802220238 05000293 44428 LER 88-002-00:on 880117, full scram trip signal followed 349 incomplete automatic actuations occurred.

8803070304 05000352 44637 LER 88-002-00:en 880130, isolation of reactor enel secondary 099 containment occurred. Caused by worn exhaust fan B damper 8803180276 05000327 44731 Forwards LER 88-037-01 providing addl info re corrective 218 action taken to ensure that ESF area / room coolers 8803080505 05000305 44636 LER 87-012-01:en 871128,two independent containment 217 isolation control valves failed to close from 8803150338 05000397

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S .. . 444716 LER 88-005-00:en 880208, control room emergency filtration d;t - ,'207:

<sys, Train B, bypass flow was greater than 1

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{ ,I 44921 LER 88-002-00:en 880218, Tech Spec 3.0.3 entered when fire

. u q,7 2115 - amper in filtration sys common suction line closed.

& .L' / 8803290250 05000364' 44904 LER 88-003-00:en 880223. fire dampers tested inoperable l$,' h '138 to. failure to close w/ air flow in sys.

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% ?- 44892 Insp Rept 99900853/87-01 on 871207-11.Nonconformances noted.

4 '.e 281 Major areas inspected: validity & basis of closure

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%@ 45046 LER 88-008-01:en 880302, determined that generic failure sh-w 142 mechanism existed for supply fans of common diesel )

hW 8804060327 05000445 05000446 45047 Supplemental.. Deficiency Rept CP-84-08 re curtain fire S;;) 070 dampers. Initially reported on 840720. Corrective 8804140123 05000440 45184 LER 88-010-00:on 880310 & 11,RWCU containment isolations  !

033 occurred due to pump room high differential temp. j

@. 8804190025 05000354 V 45208 LER 88-005-00:en 880220, inoperable inputs to primary 7, 154 containment isolation sys discovered & required 4

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_ 45216 Submits followup to 880411 telcon re 880408 routine test )

f 335 containment isolation dampers. Stuck relay replaced J.

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l' 8804270306 05000498 l 45321 PNO-IV-88-030:en 880418, Train A control room ventilation 024 makeup supply damper failed to close during 8805040079 05000423 45366 LER 88-013-00:on 880328, incomplete installation to circuits 149 in hydrogen recombiner sys determined. ,;

8805040209 05000272 45426 LER 88-007-00:en 880323,several fire danipers identified as 219 not-fire rated & duct sections penetrating barriers 8805120067 05000348 45505 LER 88-009-00:en 880412. fire dampers discovered inoperable.

029 Caused by design deficiency. l 8805310120 05000220 45668 LER 88-010-00:en 880419, identified that special 052 required due to dampers being inoperable for more i

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fy 8806$20096 05000388 hki 45698 LER 88-008-00:on 880404, ventilation supply fire dampers 181- ' plant 4 kV switchgear Room II-407 chained in open

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00 8806070150 05000461 Ilft 45770 LER 88-012-00:on 880429, standby gas treatment sys considered gj . 064- to be inoperable as result of indeterminate eq of actuator V,

C' . 8806100266 05000323 45771 LER 87-024-01:en 871107, manual reactor trip initiated after

,ff' 256 discovery of arcing in nonsafety related isophase e

x 8806230179 05000327 l' . 45909 LER 87-072-02:en 871110. potential RO initiated which 063 concluded several ESF coolers had insufficient air S- 8807260208 05000278

^ 46287 LER 88-004-00:en 880613 discovered that dampers in emergency 200 bus room ventilation duct penetration would not 8807280303 05000213 46326 LER 88-004-01:en 870406, fire barrier separating cable 351 spreading area & turbine bldg declarod inoperable.

8808020322 05000424 46370 LER 87-044-02:on-870702 & 04,two control room HVAC 298 conditions inadequately analyzed for operation in I

8808170327 05000410  !

46572 LER 88-032-00:en 880715,descovered that reactor bids l 177 ventilation emergency recirculation units were not (

l 05000369 . I 46895 LER 88-019-00:on 880719, discovered that some hydrogen )

084 skimmer VX sys damper compartment flows did not meet 3809290248 05000259 46983 LER 88-024-00:en 880828, refueling zone isolatica occurred 308 due to rupture of diaphram damper actuator.

8810180308 05000309 47187 LER 88-007-00:en 880913, leakage path between atmosphere l 356 control room identified. Caused by design discrepancy i 8810180320 05000259 47175 LER 88-029-00:on 880914 discovered that circuit controlling 100 secondary containment isolation dampers in equipment 8810130100 05000315 l 47122 LER 88-008-00:en 880907,four containment air recirculation 261 f an H skimming dampers (EIIS/BB-dmp) found disposition  ;

8812140120 05000424 47802 LER 88-033-00:en 881109 control room isolation dampers founD 229 open. Caused by personnel error.  ;

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1989 Y .18901040287 05000315 05000316 48022 RO: listed fire barriers inoperuble for longer than 7 days 4 163, allowed by Tech Spec 3.7.10 Action A.

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N 8901090319 05000454 48102 LER 86-017-01:en 860602,both trains of control room 34f ventilation sys inoperable for 4 h while at I .

18901130219 05000344 ,

48157 LER 88-018-02:en 880606, unfiltered in-leakage into control 225 room envelope exceeded.10! cfm in control room dose a

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.8301190352 05000325 48207 LER 88-034-00:en 881216, determined that condition existed 057 which could have prevented secondary containment iso

'8901110067 05000328 48138 LER 88-032-02:on 880802,both trains of emergency gas 001 treatment sys declared inoperabir. due to

8902080351 05000352 48412 LER 88-030-02:en 881003 determined that plant operated in 324 unanaly=ed condition from receipt of OL 8902210547 05000295 48544 LER 89-001-00:en 890112,OBN ave water area vent fan aircraft 223 crash damper found open w/ fan off. Caused by sticking 8903150077 05000390 05000391 48871 Final deficiency rept re emergency gas treatment sys design.

302 Initially reported on 890208. Required design changes 8901200228 05000285 48223 LER 88-036-00:en 881210, discovered that fire dampers between 259 diesel generator rooms had been rendered inoperable 8901230117 05000458 48233 LER 88-026-00:en 881214, instrument air supply to various 207 safety-related air operated dampere identified not 8903140647 05000373 48848 LER 89-007-00:on 890210. potential loss of control room 321 isolation noted. Caused by possible failure of exhaust 8904210278 05000327 49444 LER 89-008-00:en 890320, control room emergency ventilation 307 sys declared inoperable following tornado dampers

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