ML20129B046
| ML20129B046 | |
| Person / Time | |
|---|---|
| Site: | Davis Besse  |
| Issue date: | 06/18/1985 |
| From: | NRC COMMISSION (OCM) |
| To: | |
| References | |
| NUDOCS 8507290048 | |
| Download: ML20129B046 (55) | |
Text
{{#Wiki_filter:_. 1 I ' BEFORE THE FACT FINDING TASK FORCE 2 OF THE NUCLEAR REGULATORY COMMISSION i 3 * *
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Davis-Besse event : 5 of June 9, 1985 : 6 7 PROCEEDINGS
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-9 Proceedings before the Nuclear Regulatory l 10 Commission Fact Finding Task Force in regard to the {
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=11 aforementioned event, held at Conference Room 210, 12 Davis-Besse Nuclear Plnat, Oak Harbor, Ohio, i
33 commencing on Tuesday, June 18, 1985, at 4:26 o' clock p.m. 15 ! 16 17
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i / 1 I BEFORE THE FACT FINDING TASK FORCE 2 OF THE NUCLEAR REGULATORY COMMISSION i 3 * *
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Davis-Besse event : of June 9, 1985 : 6 j 7 i PROCEEDINGS 8 9 Proceedings before the Nuclear Regulatory 10 Commission Fact Finding Task Force in regard to the 11 aforementioned event, held at Conference Room 210, 12 Davis-Besse Nuclear Plnat, Oak Harbor, Ohio, 13 mmen ing n Tuesday, June 18, 1985, at 4:26 o' clock p.m.
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3 4 I 1 Tuesday Af ternoon Session 2 June 18, 1985 i 3 4:26 o' clock p.nI. 4 5 MR. ROSSI: We are ready to start. This is I i 6 going to be a discussion of the sequence of j i ! 7 events that the fact finding team has put together. } i 8! And this should be considered our 9 preliminary draft that we put together, and Wayne 8 10 will give the transcriber a copy of it so we will 11 have it for the record. , l 12 And the purpose of the meeting is to ' i 13 . discuss the factual information in the sequence of i 4 , 14 events and comments that people may have on 'it. ! i 15 If there are things Obat are incorrect, we d 16 'would like to find Uhat out now and reasons why you i 17 believe they are incorrect. I 18 Also this meeting it is our understanding 19 that you people have had discussions with IMPO's , ^ 20 offico. and B and W - and so you have had the benefit 21 of their input and presumably when we finish here 22 and agree on the sequence of events or where we can 3
,__ - - 23 agree at least know .where those items are,.that will ,
-' ' ~ ~ ' ' ~ 24 cover any disagreements or inconsistencies that
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Xi 3 ! l l 1 Tuesday Afternoon Session t i 2 June 18, 1985 i 3 4:26 o' clock p.m. 4 5 MR. ROSSI: We are ready to start. This is 6 going to be a discussion of the secuence of 7 events that the fact finding team has put together. I 8 And this should be considered our i 9 preliminary draf t that we put together, and Wayne i 10 will give the transcriber a copy of it so we will 11 have it for the record. { 12 And the purpose of the meeting is to ! I 13 discuss the factual information in the secuence of i' 14 events and comments that people may have on it. 15 If there are things that are incorrect, we 16 would like to find that out now and reasons why you 17 believe they are incorrect. l 18 Also this meeting it is our understanding 19 that you people have had discussions with IMPo's i 20 office and B and W and so you have had the benefit - 21 of their input and presumably when we finish here 22 - and agree on the sequence of events or where we can
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23-agree at 'least know where those items are, that will -
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24' cover any disagreements or inconsistencies that ' Am . aderal Reporters, Inc. 25 '
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1 I BEFORE THE FACT FINDING TASK FORCE 2 OF THE NUCLEAR REGULATORY COMMISSION 3 * *
- 4 Re:
Davis-Besse event : of June 9, 1985 : 6 7 l PROCEEDINGS 8 , , , 9 Proceedings before the Nuclear Regulatory 10 Commission Fact Finding Task Force in regard to the 11 aforementioned event, held at Conference Room 210, Davis-Besse Nuclear Plnat, Oak Harbor, Ohio, 12 f i commencing on Tuesday, June 18, 1985, at 4:26 I 13 o' clock p.m. i 14 ! 15 16 17 18 19 20 , 21 1 1 22 t i 23 24 j Reporters, Inc. 25 t
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Y 2 i 1 PRESENT:
- 2 Wayne Lanning (NRC).
3 J. T. Beard (NRC) !
- .4 ~ _ Larry Bell (USNRC) s 5 Ernie=Rossi-'(USNRC) 6 David Lewis (Attorney) 3 I 7 Bill Rowles (TED) .
8 Terry Murray (TED-Assistant Vice-President 1: 9 Nuclear Operations) 10 Pete.Wohly (Region III) [
- 11 Ned Choules (Region III) t i 12. Jim Marley (Associate Engineer) 1 _
-{ p 13 Stan Batch (Technical Project Supervisor) 14 Jacque'Lingenfelter (Technical Superintendant) j 15 Walt Rogers (Region III) i 1
16 Don Kosloff-(Region 11II) 17 Nick Jackiv.(Region III) t 18 4 "19 1 l 20 i
! 21 i
l 22 u 23' l 24 7
'O RUNFOLA & ASSOCIATES (614)445-8477 )
COMPUTERIZED TRANSCRIPTION l
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3 1 Tuesday Af ternoon Session 2 June 18, 1985 3 4:26 o' clock p.m. 4 5 MR. ROSSI: We are ready to start. This is 6 going to be a discussion of the secuence of 7 events that the fact finding team has put together. 8 And this should be considered our j 9 preliminary draf t that we put together, and Wayne ! 10 will give the transcriber a copy of it so we will 11 have it for the record. , 12 And the purpose of the meeting is to j
~w i
(! 13 discuss the factual information in the secuence of I i 14 events and comments that people may have on it. IS If there are things that are incorrect, we 16 would like to find that out now and reasons why you i 17 believe they are incorrect. 18 Also this meeting it is our understanding 19 that you people have had discussions with IMPO's 20 office and B and W and so you have had the benefit 21 of their input and presumably when we finish here t 22 and agree on the secuence of events or where we can ! i 23 agree at least know where those items are that will l l A _.,.. ,24 25 cover any disagreements or inconsistencies that {,
4 1 might exist with wha t's come trom IMPo's office and A (_) 2 B and W. 3 Okay. Why don't you people start and also 4 Region III, this is the first time you have seen 5 this too, well, first time being everybody was given 6 a copy of this sequence or events approximately an 7 hour cr so to review and get ready for this meeting 8 so everybody has had it tor about an hour but that 9 includes Region III also. 10 So any or you people from Region III that 11 have comments on the way things are said or times or 12 the way things are described, tnat ought to come out , 13 in this meeting too. So why don't we start with the l (~J) u l 14 licensee's comments on the sequence et events. l 15 MR. BEARD: Who is going to be your chiet 16 sponesman, Stan? l 17 MR. BATCH: All three of us will volunteer l 18 information as needed. 19 MR. ROSSI: Try to talk one at'a time to ) 20 maxa these easy on the stenograpner. 21 MR.' BATCH: I have had the benefit of 22 working with the tap team and IMPO wnen they were 23 here so I probably have the best knowledge of the _ 24 group in going over sequence of events. U RUNFOLA & ASSOCIATES (614)445-6477 COMPUTERIZED TRANSCRIPTION
i-5 1 In general I would-like to say I think 2 there is no significant ditterences between any of 3 the sindings from any of the people. Lots of minor 4 comments that everyone -- if you have ten dittecent 5 people watching the same th'ing happen, all ten will 6 come away with a sligntly ditteront version with the 7 sequence or exact.ly what was or wasn't important. 8 So we have a few findings on your sequence 9_ of events which we.probably should go over in detail. 10 This time now you would like to do that. 11 MR. ROSSI: Yeah, might as well go tnrough 12 them.
. 13- MR. BATCit Does everyone have a copy at L
14 the sequence ot events? 15 I guess the first -- 16 MR. BELL: Stan, as you are going through ! 17 these are you going to call out a page number and a
-18 time to make it easier. If you would, that would be 19 helpful.
1
- 20 MR. BATCH The first comment ~I really 1
21 nad was on pageftour, and it was time 1:51:42. This 22 is worded that presently the pressurizer PORV block 23' valve closed by opera tor at 2140 PSIG. 24 We would like to change that_to or suggest < O_ RUNFOLA &, ASSOCIATES (614)445-d477 COMPUTERIZED TRANSCRIPTION l
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6 1 PORV block valve started to close, started to'be rh kJ 2 closed by the operator. This is just a point where 3 it left itself tull open seat and wa sn' t tully 4 closed at that time. 5 MR. BEARD: While we are on that -- 6 MR. ROSSI: Tha t's because of a 7 misunderstanding of what the input into the sequence 8 or events recorder -- we didn't have a lot of de ta il 9 on where the signals come, but you are saying that 10 the sequence ot events intormation comes trom when 11 the valvo leaves the open position rather than when 12 it goes all the way closod? {} 13 MR. LINGENFELTER: Tha t's correct. 14 MR. BEARD: So if we inserted the words 15 " started to close" that would make this particularly 16 more accurate. 17 MR. BATCH: Yes. 18 MR. ROSSI: We may edit the words, but wo 19 understand the comment. 20 MR. BATCH: The next comment we have is at 21 1:53:22. It is actually on the paragrapn of
,2 2 description following that.
23 1:53:22 where it is worded there now it 7 24 says the number -- the aux feed pump number two was N] RUNFOLA & ASSOCIATES (614)445-8477 COMPUTERIZED TRANSCRIPTION
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i i i . t ' 7 l 1 returned-to service, and it says the control room { 2 operator controlled the. pump in manual rather than ! 3- returning it to au toma tic. - 4 -We'have had some discussiJns with the
- 5 operators and that-would be better worded to be said a 6 the. pump'would not control in automatic. The i
{ '7 control room operator' controlled the pump in manual. 3 j 8 The way . itLis presently < worded it sounds k' 9 line he didn' t try to put it -- return it in , 4 t
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'10 automatic when, in fact, he tried to return it to .
I J 11 automatic, but it would not control in automatic. l 12' MR. ROSSIt. Yes, tha t's consis te n t with 13< what we have learned from talking ~ to -the ~ opera tors , 14~ also.
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] , t 15 MR. BATCH: Now, thih -whole comment.also l 16 we would line to. move -- this. comment really .1 i .. . i ! 17 applies to later;in the incident. I t' is, as we 1 1 n j 18 worded it, it is now an accurate state' ment, but it i
- 19' is-shown just a little bit toofearly in the' sequence 1 ;
( 20: ot-events. l 21 It really applies to 2:01:13 as modified. i i j 22 Originally-the flow was cutbacx-by the operators , ) i 23 locally. He didn' t ' do . it in-the control room. f i . . 1 24 The. local operators cutback that tirst
' () RUNFOLA & ASSOCIATES (614)445-8477 f COMPUTERIZED TRANSCRIPTION 4
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8 , i 1 burst of flow. O k
.is/ 2 MR. BEARD: Why do you say that, S t'a n ?
3 Help me understand the source ot that occurrence. 4 MR. BATCil The operator we just had i i 5 additional discussions with him now just to make 1 i 6 sure so were absolutely correct. I 7 He did not control trom the control room i j: 8 the' speed -- he did not back the speed down the J 4 9 first time it occurred. It was-done locally. i i 10 MR. BEARD: What about operation of valves
- 11. which would reduce the tiow?-
] 12 MR. BATC11: lie did not reduce the 11ow by 1
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() 13 using valvos. Not to my knowledge. j 14 MR..ROSSI: Well, let me ask you this at ! 15 time 53:22 where it says aux teed water numbertwo } 16 has significant tiow, I gather there should be a l 17 comment there that. flow was controlled locally with la the -- 4 h 19 MR. LINGMNFELTER: Trip throttle valve. J ) 20 MR. ROSSI: Tha t's correct. J 21 MR. BEARD: On number two? 22 LINGENFELTER: That's correct. 23 MR. ROSSI: We can check the transcripts l > 2'4 on that, but I believe tha t tha t's wha t we were told.
- i. RUNFOLA & ASSOCIATES (614)445-8477 i COMPUTERIZED TRANSCRIPTION 4
9
.1 MR. BELL: The purpose of our entry there O
wJ 2 is to snow us where we are re-establishing teed 3 water flow into the number two OTSG not and that the 4 sentence below that is just amplification. 5 MR. LINGENPELTER: We understand that and, 6 indeed, this is where tiow started into the steam 7 generators at this time. We just wanted to make 8 everybody aware that the operator locally was still 9 controlling the trip throttle valve until about 2:01, 10 2:01 give or take a little bit. 11 MR. BELL: It is very confusing in tne 12 sequence of events review the switen goes'trom 13 manual -- auto assantial to manual to auto essential {} 14 to manual 7 15 MR. LINGENPELTER: He was attempting to 16 regain some control of it, but we believe that the 17 trip throttle valve was sutficiently closed that it 18 essentially.had all the control on the trip throttle 19 valve and was not allowing the governor to take any 20 control. 21 So it wasn't until some time later that 22 the trip throttle valve was open sufficiently to let 23 the governor take control and that was about, wa 24 tnink, 2:01. h RUNFOLA 4 ASSOCIATES (614)445-8477 COMPUTERIZED TRANS2RIPTION K _
l 10 1 MR. BELL: So the comment or the (s 2 amplitying comment needs to be moved rather than the 3 signiticant tiow of auxiliary toed water train 4 number two? 5 MR. LINGENFELTER: Tha t's correct. 6 MR. BEARD: Let me make sure I understand 7 what you are saying because I am not sure I do. 8 Are you saying that at this point in time, 9 01:53:22 where you got two flow that at this time it 10 would not control in automatic, would rot control in 11 control room manual and was being controlled locally 12 by equipment operator using the trip throttle va?va 13 at this point in timo and enen later ne still va a {} 14 not able to control it in automatic but no was able 15 to control it manually.trom tne control room? 16 Is that what you are saying? 17 MR. ROSSI: I see nodding. 18 MR. BEARD: In the affirmative. 19 MR. LINGENFELTER: He probably could have 20 controlled at in automatic. Once no gained manual 21 control of it, we are pretty certain that automatic 22 would have taken control or it as well, but ne did 23 not at enat time try it. 24 MR. BEARD: But it was later when ne got n [ RUNPOLA & ASSOCIATES (614)445-8477 COMPUTERIZED TRANSCRIPTION \ . . . ..
11 1 manual control in the control room? f* (_) 2 MR. LINGENFELTER: Tha t's correct. I 3 think we correct t h ts t thought and make it retlect 4 those comments now that I unde rs ta nd it. 5 MR. BATCH: The next comment we had was at 6 1:54:46. Tnia is the paragraph following tnat time l 7 entry. Tne same comment applies that we had 8 ess9ntially to tno number two auxiliary teed pump. 9 He would like to eliminate that tirst ! 10 sentence where it talxs about the auxiliary toed 11 pump could n o '. be regained by the control room l l 12 ope ra tor in either automatic or with the msnusi I 13 operation. (} 14 control of the turbine was maintained l 15 locally by in operator via the turbine steam trip ! 16 valve. And control room operator left the control 17 of tne number ole auxiliary teed pump turbine to the la local operators. It is the thought that we would I 19 like to have in tnat one also. 20 MR. BEARD: Let me bring up a point there 21 because I think it relates to this paragraph and the . 22 previous paragraph. l l l 23 One of the intents of having this
- 24 paragraph is that we have already said earlier tnat b)
RUNFOLA & ASSOCIATES (614)445-8477
- COMPUTERIZED TRANSCRIPTION i __
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k 12 1 the aux teed pumps had tripped out and that people 2 had gone down to try to get them operable again or 3 available again. l 4 And the intent of this paragraph really is 5 to say you are in an i n t e'r m e d i a t e phase in the 6 recovery of this particular piece of equipment where l l 7 you had gotten to the point where you could get ! 3 througn or local control, but the point.we are l 9 trying to make at this point in time you do not have l l 10 a utoma tic control in the control room. You do not 11 have manual control in the control room or have 12 elected not to use it for one reason or another. 13 That's part ot the story we are trying to {a~} 14 convey, to what degree you had recovered that 15 availability of that pump. 16 MR. LINGENPELTER: I understand that. 17 MR. BEARD: I wouldn't like to leave the 13 thougnt in that at this point in time you had not 19 regained control in the control room. 20 MR. ROSS1: Well, what you are suggesting 21 at 54:46 is that you strike out tne first sentence. 22 MR. BEARD: Tha t's what I read the last 23 suggestion is. 24 MR. ROSSI: Then you say control of the (s) RUNFOLA & ASSOCIATES (614)445-8477 COMPUTERIZED TRANSCRIPTION I t
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/ 1 turbine was maintained locally by an operator via k) 2 the turbine steam trip valve.
3 The control room operator left the control 4 locally control basically. Tha t's what you are 5 saying. 6 MR. LINGENFELTER: That's assentially what 7 happened there. 8 MR. ROSSI: That one I understand your 9 comment, and we will record the comments. We will 10 check with what we learned trom the equipment 11 operators wno were there because in some or these 12 cases tney did tell us that they had conversations 13 with the control room and there may have been (} 14 difticulty doing it from the control room, but wo 15 will try to loon a t that again consistency also. 16 MR. LINGENFELTER: Don' t confuse -- he, I 17 believe, had ne tried to assume manual control or 18 automatic control at this time it would not have 19 Deen available. It simply I did not attempt to d'o 20 it. 21 MR. ROSSI: That may be a little different 22 than what we were told and that, again, we can check, 23 but do we understand the comments well enough to 24 checx it now? J. T.? O RUHFOLA & ASSOCIATES (614)445-8477 COMPUTERIZED TRANSCRIPTION
14 1 MR. BEARD: I believe I do. p) ( 2 MR. ROSSI: r And I think we have -- 3 MR. BEARD: We will have to consider now 4 we want to end up with the final wording. 5 MR. LINGENFELTER: Try to maK6 it 6 understood that they had the problem they were 7 having was the trip throttle valve was cranked down 8 so tight tnere wasn't any control lett toe the 9 governor. All the additional pressure was scross 10 the trip throttle and until they opened it up tar 11 anougn to get the control there was nothing they 12 could do. It was just a tine point.
/~T 13 MR. BELL: What you just described now V
14 concerns numoer two aux teed pump? 15 MR. LINGENFELTER: Both of them. 16 MR. ROSSI: What we were talking aoout was 17 number one. 18 MR. LINGENFELTER: The case was true on 19 both of them, but on number two they managed to open 20 it up tar enough to allow them to get msnual control 21 in tne control room a Aittle while later is wnst 22 happened. 23 MR. BELL: Did you see our entry under on 24 page 3 under 01:44 to 01:527 The last sentence RUNFOLA & ASSOCIATES (614)445-8477 COMPUTERIZED TRANSCRIPTION 1 __
15 1 under entry number one we reterred to the manual n (-) 2 speed control by tna operator. l 3 MR. LINGENFELTER: it i g h t . l' 4 MR. BELL: You agree with chat comment? ! 5 MR. LINGENFELTER: No p r o'a l e m wnat so ever. I 6 MR. BELL: This es t a t e m e n t. on page tour is l l 7 somewhat redundant to that. 8 MR. BATCil It could appear in contlict r i 9 with the way it was written. l l 10 MR. ROSSI: Okay. J. f., any questions on i 11 that? i l 12 MR. DEARD: I think I understand your l l 13 comment. [} j 14 MR. ROSSI: Fine. l l 15 MR. B A T Cli s Page rive we had one last i 16 comment. In the third paragraph of additional l 17 complications there we are talxing about the deaupse-I l 18 heating spray tor tne auxiliary steam system allowed j 19 water into the main steam piping. 20 And then it says the water alug damaged i l 21 one of the main turbine Dypass valves. I would liAo l ( 22 to ado the sentence to that part of this. It is , 23 believed. We are not sure. We are less positive on 1 ! 24 that at this point in time.
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RUHrOLA & ASSOCIATES (614)445-d477 COMPUTBRIZED THANSCRIPTION
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? 16 I l' MR. ROSSI: How about it we say when 2 vacuum was restored and the MSIV'a opened, the water
.3 - slug apparently damaged the main-turbine bypass I-4 vslves. ;
I l 5 MR.'ROWLES: Or one of tho' main turbine > 6 bypass valves was damaged. 7 MR. ROSSI: Well -- 8 MR. BEARD: We can taxe care of the t 9 thought:and try to get something in there that this 10 is, as I understand your comments, is that this is 11 the best available information today we believe, but 12 it is subject;to clarification and changes when more 13 information is available.
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14 MR. LINGENFELTER: Very good. j 15 MR. BEARD: It is not our intent that the l 16 preliminary sequence of' events that nothing could j 17 over change. It is preliminary. l 18 MR. ROSSI: Yeah, one of tne things that 19 we intend eventually to do, we are going to do this l P 20 revision here and call it reviolon one whatever we , i 21 do with your comments and then we are going to let l 22 it go bacx to headquarters people in Washington as 23 our revision one preliminary sequence of events. , 24 And then over some time period we will be O RUNFOLA & ASSOCIATES (614)445-8477 COMPUTERIZED TRANSCRIPTION i l
A 17 1 going through mostly transcripts and records and r (_3) 2 trying to fine tune it trom here, but that's wnat we 3 intend to do with it, but we do intend to do some 4 more fine tuning by reading things and that kind or 5 thing. And at the time we send it to he a d q u'a r te r s , 6 we will give copies to tne licensee and to Region 7 III also. 8 Now, do you have any other comments? 9 MR. LINGENFELTSR: I don't think we do. 10 MR. ROSSI: I gather tnat we are 11 reasonably consistent with what IMPO's ottice found 12 wnen they were here? There is no glaring {} 13 inconsistency? 14 MR. LINGENFELTER: Nothing we have noticed. 15 MR. ROSSI: Okay. You want to snow on tno 16 record, they nodded their heads here in the 17 attirmative. 18 Okay, now, Region III, do you have any 19 comments that you want to make? 20 MR. ROGERS: Yeah, I guess under the 1:35:31 21 entry. 22 MR. BEARD: What page a"e you on? 23 MR. ROGERS: First page. The Lirst 24 sctuation, channel two actuation, I gueas right now, (~') RUNFOLA & ASSOCIATES (614)445-8477 COMPUTERIZED TRANSCRIPTION
18 1 you all are pretty much in tne main steam isolation O't s_/
- 2 valve to tne full actuation of number two?
3 MR. ROSSI: No, it is not our intent to 4 attribute the MSIV closure to anytning right now. 5 In our mind, tha t's totally not understood yet. 6 Tha t's one of the things to be determined 7 in the trouble snooting. And all this is a sequence 8 of evonts of what nappened in the best order that we 9 can give them from ope ra to r descriptions and 10 computer print-out. We don't claim to know tne 11 causes of many tnings in nere. 12 MR. ROGERS: I would guess I just suggest {} 13 that by this it inters tnat tne actuation enannel 14 two did actuste. 15 I thinA right now that you can say that 16 tne computer noted a tull actuation channel two tnat 17 it nad a signal that the computer saw not la necessarily that the logic saw. 19 I know this is kind of a fine point on 20 wha t's saying here that tne computer annotated that 21 an actuation channel two trip. 22 MR. BELL: Well, could we solve that 23 problem by making that a separate entry under the 24 01:35:31 time frame so it doesn' t read -- O RUNPOLA & ASSOCIATES (614)445-u477 COMPUTERIZED TRANSCRIPTION
19 1 MR. ROGERS: That might help. {~)'t N- 2 MR. BELL In your connotation. 3 MR. BEARD: Only two comments, I think, 4 Walt. 5 MR. ROGERS You don't want to leavo 6 credence, you don't want to leave the idea tha t you 7 are saying that the MSIV's went closed oecause og 8 actuation channel number two because I thinK there 9 is still some trouble shooting that everybody wants 10 to do to satisty enemselves tha t's what it was. 11 MR. ROSSI: We may Anow less in the room 12 about that because we have concentra te d on a ;
^N 13 sequence of events at this time and only discussed i
O( 14 the. procedure aspects of how people are going to do 13 the trouble shooting. 16 And we don't pretended at this point in 17 tims to know anything about the causos og most of 18 this stutt, and we are holding ott any conclusions 19 on that. So with that change needs to be made, I 20 believe. 21 MR. BEARD: It is, at least my 22 understanding though, walt, that it there nad been 23 an actuation og the steam feed rupture control 24 system on low level in the steam generators that at i f'\
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RUNFOtA & ASSOCIATES (614)445-6477 COMPUTERIZED TRAt1SCRIPTION
20 1 least one ot the MSIV's would have been signalled to l /~N (J 2 close? 3 MR. ROGERS: Both of tnem would nave been
-4 signalled to close it one tull actuation --
I 5 MR. BEARD: The real issue seems to be not l 6 that did the actuation cause tne MSIV's to close en s 7 much as was there really an actuation because it l 8 there has been an actuation, this would be the l l 9 expected result, the MSIV's would start closing; in l l l 10 tnat corrs:t? 11 MR. ROGERS: Yes, plus a number of other l l 12 equipment that would also move. The main thing is {} 13 whetner there wss a tuli actustion of that enannel 14 or whetner there was just a hsit actuation and 15 something else caused the MSIV's to close. l ( lo MR. ROSSI8 Tell me, I gather the computer 17 print-out a tuli actuation at 35:31 and cleartng at i 18 35:347 l ') MR. DEARD: Let me clarity that, with the l l 20 benefit ot the licensee's explanation or now we 21 should interpret their print-outs, it is my l l 22 understanding that the sequence of events recorder 23 printed out tuli actuation of one of the logic 24 actuation channels of the steam teed rupturo control ' ~] l e RUNFOLA 6 ASSOCIATES (614)445-0477 COMPUTERIZED TRANSCRIPTION i _ _ _ . _ _ _ _ _ _ _ . _ _ _ _ . _ . _ _ _ _ _ _ _ _ ____________.______________._________________.________________.___.____.___j
21 1 system.
)
(~/ x_ 2 MR. ROSSI: Channel two. 3 MR. BEARD: Yean. The alarm printer 4 printed out at the same time that for this channel 5 it is a half trip /tull trip. So it is a little 6 ambiguous. 7 Now, the explanation that we were given on 8 how the system worxs, the print-outs .i n d whatnot, is 9 that we should interpret those two entries as mostly 1 10 being a tull actuation as indicated by the sequence 11 of events. 12 And tha t's the reason this thing is
/~ 13 written the wey it is. In other words, last time I
(>} 14 guess we had some tecnnical discussion how to 15 interpret tne alarm print-outs and the sequence ot to events print-out. 17 And I think that it was pointed out to us lu that initially tnis may have been believed to have 19 been a spurious entry, and it was only a partial 20 trip rather tnan a tuli trip, but now thoro 1's some 21 information that you folks nsve arrived at to cause 22 you to believe the most actually two pirtial versus J .) tuli lesda you to believe it is a tuli trip og one
- 24 of tne two logic actuation channels.
HUHrOLA & A!!$0CI ATES (bl4)44S-0471 C O M P U f f.H 12 E D fMANSCRIPTION __________-__-_y
I 22 1 And based on that understanding this is
) 2 written that w y. Now, is my understanding correct 3 or am 1 all wet?
4 MR. l.INGENFELTER: That is correct when 5 you use empnasize the word "we believe" tha t's tne 6 best. 7 MR. BEARD: Tha t's right. 8 MR. LINGENFELTER: Again, given the -- it 9 we were to assume that the alarms as indicated 10 runctioned correctly then tuli trip is indicated. 11 MR. BEARD: This is the best information 12 available at tnic time. (} 13 MR. ROSSI: Maybe what you could do is 14 move tnst both MSIV's start to close down as a 15 separate item. Tha t's one thing. 16 And the otner thing that could be done to 17 just put in some parenthesis after that steam and is teet water rupture control system trip on steam low 19 level to give the flavor that this is one of the 20 things tha t's more in question than a lot at otner 21 things. 22 What about thate J. T.7 23 MR. HEARD: I cortainly agree that it 24 would be a claritication essentially on the point O HUNFOLA & ASSOCIATES (614)445-0477 f COMPUTER 1%ED TRANSCRIPTION I _ _ _ _ . _ _ _ _ _ _ _ _ _ _ . . _ _ . _ _ _ _ . _ _ . _ _ _ _ _ _ _ _ _ _ _ _ _ . _ _ _ _ . _ _ _ _ . _ _ _ _ _ . _ _ _ _ _ . _ _ . _ _ . _ _ _ _ _ _ _ _ _ _ _ _ _ __.__ .______ j
c 23 L l 1 that. Walt brought upi. tha t one is not a direct cause ; ( 2 ot the other necessarily. To maxe it a separate j 3 entry 1and some way we need to clarify this' entry 4 about the actuation I believe. ; 5 We can talk sbout the exact words, but I 6 thinx it is a good thing to clarity it. j 7 MR. ROSSI* Fine. Anything else? 1 8 MR. ROGBRSt I would just -- some points i j 9 that maybe this will help me out that when they i 10 started the start-up feed pump, it may be I 11 appropriate to put what the water source was. It is 4 12 my understanding tha t that was tne daa ra tors and not . l f(} i 13 tne CST. 14 MR. BATCH Tha t's ' correc t. 1 15 MR. BEARD Do you remember whSre that was? 16 MR. ROGERSt That would be at page 4, 17 1 51:23. In terms of tnermal shock to the teed . t 18 water nozzles, the water source at that point does 19 make a ditterence. 1 20 MR. ROSSI Is it possible to tell that 21 from the computer print-outs on the source ot the i i i 22 water? i 23 MR. SCARD: I don't believe those valves 24 are instrumented. This is one of the areas wnere O RUNFOLA & ASSOCIATES (614)445-8477 COMPUTERIZED TRANSCRIPTION ' t
. - - . .- . . ~ ~ . - _ - - . - ~ . - ~_.. - - . _ - . . _ _ . - _
LJ i ! i 24 1 because of lack of print-outs on the computer wo had 2 to rely more-heavily on operator interviews. I ! 3 MR. ROGERS: Because I don't know wha t the l 4 water source was, but it it was the dearators -- 5 MR. BEARD: I believe tha t's consistent, l I 6 Ernie, with what the individual had indicated to us. l 7 MR. ROSSI: What I-suggest we do on this 8- one it it is more or less unknown,- tha t's a detail l l 9 that we don' t' have z to put in.nere. I 10 And tha t's a detail that has to be 11 resolved in terms of the steam generator thermal 12 shock, and we can leave it out now. And then as we 13 go back and do more fine tuning and learn more, we (]) , 14 may .s d d it.to a later revision once we are more suwe i 15 of it. That's what.my suggestion would be. 16 MR. ROGERS: About the only other real 17 major one I have is on page 4 at 1:53:56, the PORY r I 18 bioch valve is being reopened by tne operator. 1 19 I might suggest you put an annota tion 20 there that the PORV was' closed at that point,in time I 21 since 1t'is apparent because there is no 22 depressurization of the reactor coolant system when 23 the block valve is open. 1 24 You'do show _that it did not close at ; l j O dUNFOLA & ASSOCIATES (614)445-8477 COMPUTERIZED TRANSCRIPTION l , r f l
25 1 1:51:18, but it doesn't show that it actually got . () 2 closed. I do agree that in the sequence ot events 3 it it was, in fact, still open there would be a lot 4 of other things happening, but just for the sake of 5 claritication for' people reviewing the sequence of 6 events, I think'it might be appropriate. 7 NR. BELL: I think the reason we didn' t 8 include that was we wanted time to examine some da ta 9 from the quench tank levels and pressures to make it 10 clear in our own minds that the valve was leaxing 11 back. 12 MR. ROGERS:- It might have been weeping. (; 13 MR.-BEARD We_ considered adding that 14 because we thought.it was pertinent information, but 15- we weren't in the position to'say that was-the case. 16 MR. ROSSI: That falls in the category of 17 source of the water in start-up feed pump. Tha t's
'18 : something we may add later on;as we getfinto the 19 finer details.
20' MR. ROGERS: I guess'there is one' thing, 21 it is our understanding that there was a tailure of 22 one of the start-up feed pump: valves to open at some' 23 point-in this sequence of events. _. 24- I am not sure when this was. supposed to
&' ASSOCIATES (614)445-8477-RUNFOLA COMPUTERIZED TRANSCRIPTION 4
-- e .c --e-- ,, -
f - , -, - -r - , - -
f 26 l I happen or they found out it wouldn't go open when
~
ks) 2 eney tried to get it open. f 3 MR. ROSSI: That wss my understanding too, 4 and I thought that wo were told that the start-up 5 feed wa te r valve -- what is it SP7A that there was 6 some kind of problem with that to steam generator 7 two. 8 MR. LINGENFELTER: There was originally 9 some contusion in the operators' minds when they 10 went to reset the block as far as trip on that valve. 11 I don't Know all the details myself, but 12 there was some light bulbs that burned out 13 apparently. The valve itself functioned as raquired (vl 14 once it was blocked and, in fact, the print-out snow 15 that tne valve actually did come open when the 16 operator triod to move it. 17 MR. BEARD: So it is an indication anomaly la rather than a valve performance. 19 MR. LINGENFELTER: That's correct. 20 MR.'ROSSI: What I would suggest we.do on 21 that one is maxe an annota tion in here that at this 22 time there is a question on the ope ra ti on of that. 23 That has to be resolved and then, you know, 24 so we can get ourselves out tomorrow and then just (
)
\sj) {
RUNFOLA & ASSOCIATES (614)445-8477 c COMPUTERIZED TRANSCRIPTION
- - _ _ _ _ _ _ _ _ _ _ _ )
27 1 make an annotation tnat tnere is a question as to , ~. (-) 2 whether the valve worked properly. 3 And tha t's something we will try to resolve 4 in a la te r revision, but I think that at some point 5 we nave been told that, there was some -- so we will 6 just put it as a sequence. 7 MR. LINGENFELTER: We nave any indication 8 of L position and actual flow througn that tnat we 9 Know it opened. 10 MR. BEARD: What source? 11 MR. LINGENFELTER: Computer print-out. 12 You nave got the enarts. / ~' 13 MR. BEARD: Wait a minute. I have got the (>) 14 alarm print-out, and I nave got tne dad's. 15 MR.-LINGENFELTER: The dad's. 16 MR. BEARD:. The dad's has it? 17 MR. LINGENFELTER: Yes. 18 MR. BEARD: May I ask a question. 19 MR. ROSSI: Go ahead. 20 MR. BEARD: For the saxe cf being 21 technically perfect, thore is one local term that 22 you have:here on page 3 the second entry the time is 23 01:43:55. There nas been a lot of discussion on the
, 24 particular term as to wnst its proper name is.
() RUNFOLA & ASSOCIATES (614)445-8477 COMPUTERIZED TRANSCRIPTION
i N x N 2e 1 This is the rupture control systems (J 2 initial reset and bypass is what we believe to be 3 the correct term and just to make sure we haven' t 4 made a mistake, I would like to ask if anybody 5 remembers it being difterent than that with 6 certainty? 7 MR. ROSSI: We will leave it the way it is, 8 and tha t's a detail that we can correct later on. I 9 had another one since you brought that up in the one 10 just above on the controls tor AF 599 and AF 608, we 11 indicate tha t's from the main control panel and it 12 is tnat vertical panel behind.
/~' 13 And is main control panel used for that b) 14 also, for the vertical panel?
15 MR. LINGENFELTER: Yeah, I don't think 16 there is -- 17 MR. BATCH: There is no problem with tna t. 18 MR. BEARD: The sense of tnose words since 19 it was main is to maxe the distinction it is a panel 20 in the main control room versus a panel outside tna 21 normal ope ra to r 's --- 22 MR. BATCH: This isn't in the control room. 23 So it you want to reword that to say from a panel in 24 the control room that would be fine. L) . RUNFOLA & ASSOCIATES (614)445-8477 COMPUTERIZED TRANSCRIPTION t-
, \
/' \
! 29 1 MR. KOSLOFF: Isn't that sometimes
) (._) 2 referred to as a SFAS panel?
3 MR. ROSSI: Or back panel. 4 MR. KOSLOFF: Since tha t's where all the 5 SFAS -- 6 #1 R . BEARD: Most presently as the back 7 panel, but there is a connota tion, a strong 8 potential for confusion of readers away from this 9 plant site that it you say back panel, you are 10 talxing aboes repething in the backside of some 11 control building and that;. I was just wanting to 12 maxe sure we realize tnat the operatua- '<
- r e in tno 13 main control room here.
{') 14 MR. ROSSI: Fine. Then we will leave it 15 that way. Anything else, Walt? 16 MR. ROGERS: Last point, and I-guess it is 17 on page 3. It is between your 1:44 and 1:52 time 18 entry. 19 And that's I get from this that_you had 20 trouble with both auxiliary feed pump controls in 21 the speed on those or the governor controls. Maybe 22 I am using an assumption. 23 It says that you had to taxe manual 24 control of the turbine trip throttle valve was (~b t
f RUNFOLA & ASSOCIATES (614)445-8477 COMPUTERIZED TRANSCRIPTION l
t
30 1 required to bring the turbine up to speed.
) 2 I tninx you are talking about that was 3 number'two s t. that point in time so there was some 4 problem with both auxiliary toed pumps, and I don't J 5 Know if'I am allowed to go any further with that at 6' this time --
i
-7 MR. ROSSI: There was at least a problem 8' waere . they had to use pipe wrenches, as I understand 4
i 9 it, to.open the trip throttle valves and there was 4 10 some question as to when they were and weren't open 11 from what we havelbeen able to determine that you ,
-12 could-take the hand wheel and turn it until it i-
{)- 13 wouldn' t turn it any more by hand and that might } 14 o nly tus because you were' taxing up the slack until 15 it.was. hold close by-the pressure and then they 16 needed a-wrench to open it further.. 1 17 Now, I guess there is a question of la whether some'of this should say manual control ~or j 19 manual operation of the trip throttle valve was 20 required to. bring the turbine up.to' speed and maybe , 21 there is no difference. I don' t = xnow. - 22 MR. MURRAY: B o t h' phrases 1 sounded the same 23 to me. It would.' sound the same to me -- l
. I
- 24. MR. BEARD: It'they are tnat close-I.would 1
- i. .
RUNFOLA & ASSOCIATES (614)445-8477 < COMPUTERIZBD-TRANSCRIPTION 4 l
. I
31 1 suggest for expediency purposes we not maxe changes. () 2 A lot of people are anxious to get those. 3' MR. ROSSI: Now, for the purposes of 4 Region III doing their-normal job with the licensee, 5 you Know, you people have this sequence of events 6 now, it is in the transcript and, you know, we are
; -7 going to maxe some modifications to it. And it will I
8 be called revision one but, you Know, please feel 9 free to discuss it between you on anything you-need 2 10 to do or go about your normal job. 11 MR. ROGERS: Thank you.
; 12 MR. ROSSI: We are going to try to retina
{} 13 it as necessary. In our report-will have a 14 narrative description of wha t we nave learned t r o.n 2- , 15 ta1xing with the operators about what they did and, 16 of course, all of tha t will.be available. 17- MR. BEARD: I thinx we ought to add, Ernie, 1 18 there ~ are still some individuals that we have not
- 19- interviewed, and there are some other individuals 20 that we need to call back and either ask some f 21 additional cla rifica tion ques tions or whatnot.
22 So this may be refined in terms of-new 23 information as we learn more. 24 MR. ROSSI: Tha t's fairly unlikely because RUNFOLA & ASSOCIATES (614)445-8477 COMPUTERIZED TRANSCRIPTION
, , my . . - + - . - y , - _ ,_ . . . - -- y- s,y - . . - . ,-
32 1 most of the interviews that we have lett will be on N/ 2 subjects that are not related to the sequence of 3 events other than perhaps Walt, and he is here to 4 comment now. 5 MR. ROGERS: Other than that, just looking 6 through it, it essentially balances with what we see 7 in the computer print-out. We consider wha t's 8 pressnted as sequence of events is a logical 9 statement of what the computer print-outs show. 10 Realizing you all have had the benetit ot 11 doing a full interview or the operating shitt, you 12 all had more information than we do. 13 MR. BELL: In summary then I have listed (] 14 tnree items that may need some turtner examination. 15 First item I have listed is the source of suction to 16 the start-up feed pump. 17 The second item I have listed is the 18 operability of SP7A; and finally, the question 19 concerning the position of the PORY itself after the 20 block valve was opened, reopened. 21 Any disagreement on those three items? 22 MR. ROSSI: You mean items that are still ; 23 in question? _ 24 MR. BELL: Yes. RUNFOLA & ASSOCIATES (614)445-8477 COMPUTERIZED TRANSCRIPTION
.7. _ . , -
J - 33 1 MR. BEARD: I get the general impression , 2 that we are really fine tuning here and tnat we are I
'3 at IvoryEscap level of being consistent here. l i
4 MR. LANNING: Let me asK the question, are , 5 there any significant omissions trom the sequence ot ?. 6 events that you think-should be added? 7 MR. SATCH: No, we see no additional ones. 8 MR. LINGENFELTER:' Not tnat we are aware. 9 MR. ROSSI: You listed the things to be ; 10 looked at. Well, is there any reason that we need 11 to -- let me ask one other question then. I 12 In the times that are on here, maybe Larry. i 13 and 4. T. can mention where you got most ot ene
- {}
14 times and just see if people in the room feel tnat
- j 15 tha t's the way we should.have gotten it.
, 16 .J. T., can you summarize how you got the , l 17' times.' i
'18 - MR. BEARD: .What we did is based on the 19'- intormation provided by you folks that the times on
-1 20 the sequence of events print-outs are the most i 21 accurate source wnen contrasted or compared to ~ tne 9
22 alarm print-out. s 23 Wo.did an upgrade 1ot all these1 times,'went i 24 back to the sequence of events print-out and for 4
- ("#
- RUNFOLA & ASSOCIATES (614)445-8477
- COMPUTERIZED TRANSCRIPTION
'k I. >
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- 34 l~ those items which there was an' entry we used tnat 2 time rounded to the nearest second.
3 We did not carry this to the milli second i j' - 4 although there was some items-like,.you Know, 34 h 5 seconds and 7 milli seconds. 2-6' We Just rounded to tne nearest second. 7- And'then for those items-that are not on the 8 sequenceJof events print-out, we used'the values
~
9 from the alarm print-out. 4
'10 MR. BATCH: Tha t's fine too. ,
11 MR.'ROSSI: Okay. Well, anybody have i 12 anything else they want-to say on tnis subject? (} 13 Okay. Then why don't we call the-meeting to a close l4 then. We are ott the record. l 15 - _ _ _ _ 16 The'reupon, the. meeting ~ was , i 17 concluded at.5:06 o'clocx p.m. 118 _ _ _ _ _ 19 20. 21 I 22; 23 24 RUNFOLA & ASSOCIATES '(614)445-8477 COMPUTERIZED TRANSCRIPTION-
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35 1 CERTIFICATE rm 1 (_) 2 I, Kim E. Snyder, a Ragistered 3 Professional Reporter and Notary Public in and for 4 the S ta te of Ohio, do hereby certify tha t I took the 5 proceedings and that the torogoing transcript of 6 such proceedings is a full, true and correct 7 transcript of my stenotypy notes as so taken. 8 I do turtner certify that I was called 9 there in the capacity of a Registered Professional 10 Reporter, and am not otherwise interested in this 11 prococding. 12 IN WITNESS WHEREOF, I have hereunto set my (~} 13 nand and atrixed my seal or ottice at Columbus, Onio, 'u s 14 on this ) day of (h/gd[_ , 1985.
/ 4?? -
l (h KIM E. SNYDER, Registored 17 Protessional Reporter, Notary Public in and for the State 01 Ohio. 18 19 My Commission expires January 12, 1989. 20 21 22 23 24 () RUNFOLA & ASSOCIATES (614)445-8477 COMPUTERIZED TRANSCRIPTION
l l l l
- DIRECTIONS' FOR MAKING CORRECTIONS 4 -
() If you have any corrections that you wish to make on your transcript, please do so on the following page 1 in the following fashion: Indicate the page of the correction, the line number, and then the change to be made and the reason for making the change. Date and sign all correc-tion pages that correspond with your transcript. l 4 ' (2) l E h e i a 1
Page Line Correction or change and reason therefor 4
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j O I { l 1 i 41 l ia l Paeje tio DATE SIG?iATURE L ,
4 SEOUENCE OF EVENTS Davis-Besse
. . Complete Loss of Feedwater Event j) .'
June 9, 1985 . i . NRC Fact Finding Team [ 3:ooPM ,
- 1. Status: Preliminary (Rev. 0)' ~11.00 " June 18, 1985 V, -~
. e
- Unexpected or off-normal response '
Initial Conditions
- Unit operating at 90%
- Number One Main Feedpump (MFP) in automatic control
- Number Two Main Feedpump in manual
- One Source Range Nuclear Instrumentation Channel inoperable
- Safety Parameter Display System (SPDS) inoperable .
. i Transient Initiator .
j ....t_ , *01:35:00 #1 MFF Trips _ .
~,,
.": ' . f._ . - MFF flow increases; MFF turbine trips on overspeed.
. - 1.::. :.
. .c. ~
...i- %
.! . c. .U - @. Systems Response / Operator Actions to Partial Loss of Main Feedvater' t
f -- .~:..z :~7- z.,.
+ s::w y u.ye .: .. vmwvwn.-w:5.7. .o m . : 7' 'y -
l 01:35:01 Unit runback toward 55% at 50%/ min initiated.' ';._ , 01:35:21 Opera::or increases the speed of #2 MFP turbine. Pressurizer spray valve manually opened to 100%. 01:35:30 Reactor Trip + Turbine Trip - RCS High Pressure (2300 psig) from 801 power. f
*01:35:31 Steam & Feedvater Rupture Control System (SFRCS), trip on S/G low level, actuation Channel 2. Both MSIVs start to Close.
01:35:34 SFRCS actuation signal clears.
' ~
*01:35:36 Main Steam Isolation Valve (MSIV) #2 has closed. .
*01:35:37 MSIY #1 has closed. '
With both MSIVs closed, the source of steam for #2 MFP turbine is isolated. Steam from main steam piping and moisture separator reheators continued to drive #2 NFF for a while. 5 01:35:45 Pressurizer spray valve closed.
. 4r
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1
SEQUENCE OF EVENTS l 5% i
' 01:35:)( 1 Once Through Steam Generator (OTS0) levels at norma?
p,ost-trip level (35 inches).
*01:40:00 OTSG 1evels begin to fall from the normal post-trip level .
System Response / Operator Actions to Complete Loss of Main er Feedwat
~
01:41:04 3 .. SFRCS low OTSG 1evel (26.5 in.) Actuation Channel 1 actuates; this actuation causes Auxiliary Feedwater . Pump (AFP) #1 to be aligned to feed OTSG #1. ,
*01:41:03 The control room operator attempted to manually initiate SFRCS; however, he incorrectly actuated the SFRCS on low steam pressure instead of the desired low steam generator level.
He performed the manual actuation by depressing the top switch in both strings of manual actuation switches for the respective STRCS actuation channels. each SFRCS actuation' channel sensed that its respectiveTherefore, steam generator was inoperable. then attempted t'o align AFP 1 to feed steam generator 2SFRCS actuati and SFRCS actuation Channel 2 attempted to align iFP 2 to
._ feed SG 1; both actuation channels,.however, closei their respective steam generator containment isolation valves
_s s.
- s (AF-599, from reaching AF-608), which prevented any auxiliary feed flov w .,. ,... g the.:.3 steam g . generators'.'t,$ M.A 5.tfY plIT C.e y'2 e .e ; ;., . IL.
.p.pg.p; Per the SFRCS design, valves positioned by the lov level trip on SFRCS priority pressureChannel trin. 1 vere repositioned by the higher SG 1, MS 106 had started open in response to the SFRCSThe AFP actuation Channel 1 lov level trip.
initiation of the low pressure trip, the valve shcu ld hFollowing ave the manual continued cycled closed. opening to its full open position before it have been about 50-60 seconds. WThe valve howeverThe entire returned to its closed position in about 18 seconds. { This indicates that the open cocmand to the valve did { not seal in as designed. } 01:41:13 l i SFRCS 1evel. actuation Channel 2 tripped on low steam generator Siuce the low pressure trip already present had priority, no change in component actuation occurred.
*01:41:31 AFP 1 tripped on overspeed.
I
*01:41:44 AFP 2 tripped on overspeed.
O G.7' : * :: . '- ' T * - r. *
... N
_ _. _ _ _ . _ - _ _ - - - - - ~ - _ _ ' _ _ _ _ -
- f. . .,
-3' -
SEQUENCE OF EVENTS Ana. System Resconse/Ocerator Actions to Comolete Loss of Feedvater
~
01:42:00 Manual reset of SFRCS lov OISG pressure actuation., ,
*AF-599, AF-608 should re-open automatically, but did not.
*An attempt was made to re-open AF-599 and AF-608 from the main control panel, but the valves did not respond. ,
01:43:55 Assistant Shift Supervisor vent to SFRCS cabinets (behind the control room a.rea), opened the doors, and operated the SFRCS " Initial Reset and Bypass" function in an attempt to reset any automatic safety signals to AF-599 and AF-608.
*The valves remained closed.
*01:44 - 01:52 The Shift Supervisor dispatched Equipment Operators into the plant to operate the following equipment:
(1) Two Equipment Operators were sent to 'he Auxiliary. Feedvater Pump turbines to manually restore the , AW pumps to service. No. 2 AW turbine over speed
' trip was reset at 01:45:50. Manual control of the turbine trip throttle valve was required to bring
_ the turbine up to speed. No. 1 AFP turbine was reset
-. ~. n . and speed was controlled locally throughout the..s ...
y-y,y
- 3. _~. . R recovery. ,. ~ ' ?s;-f. ..: - >. 4:., i.iM:Y. 4 : x..* w .' ~
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. - .. . i ~-
y.,.+33:, (2) The Assistant Shift Supervisor left the control room to place the startup feed pump in service. This evolution required opening the pump suction valve, the pump discharge valve, and two cooling water valves. In addition, the control fuses for the pump circuit breaker were required to be installed. The startup
- feed pump was started at 01:51:23.
(3) Two equipment operators were sent to open OTSG Auxiliary Feed Isolation Valves AF-599 and AF-608. These valves are the containment isolations for the AW system. The operators moved the valves fron the closed position, and the motor operators opened the valves. Computer printouts indicate that the #2 OTSG Valve AF-599 was open at 01:47:48, and the #1 OTSG Valve AF-608 was open at 01:49:28. - 01:47:33 OTSG #1 belov 960 psig and decreasing. 01:48:49 Pzr. PORV opens first time at 2433 psig (2425 setpoint).
*01:48:51 OTSG #2 belov 960 psig and decreasing.
e
.L. ?f?c:gf=.= ^* l - y - j.:
~
(( ... . l.. -s-SEOUENCE OF EVENTS
. 01:48:52 Pzr. PORV has closed at 2377 psig (2375 setpoint).
01:50:09 PIr.PORYopenssecondtimeat2434psig. 3 01:50:12 Pzr. PORV has closed at 2369 psig. E
; 01:51:17 OTSG SG #1 level. falls below eight inches. ,
s
*01:51:18 Pzr. PORV opens third time at 2435 psig; did not close. ,
01:51:23 Startup feed pump motor on. 01:51:42 Pzk.PORVblockvalveclosedbyoperatorat2140psig. 01:51:42 RCS Loop #1 reaches a,mininum pressurg of 2081 psig. Loop #1 T-hot = 588.6 F; Tave = 587.5 F. , 01:51:49 Accoustic monitor indicates no flow thru PORV/ block valve.
.01:53:00 RCS loop #1 T-hot reach'es peak value of 593.5 F. ,
...~;,.-c....
01:53:22 AFW #2 has significant flow. g .
, ,' [ . . . When AFP 2 was returned to service, the control room L - . ~. ~; , < % '_
~ operator controlled the pump in manual rather'than.
f, . f ~IE. 4.756. . ~-~returning
~ it to the. Automatic. ,'-
7'. 01:53:25 RCS Tave reaches peak value of 592.3 F. 01:53:35 SG #2 returns to above 960 psig. 01:53:56 PORY Block Valve reopened by operator. 1 01:54:45 SG'#1~ return to above 960 psig. 01:54:46 AFW #1 has significant flow. Operation of AFP 1 turbine could not be regained by the j control room operator in either the Automatic or the manual mode of operations. Control of the turbine was maintained locally by an operator via the turbine steam trip valve. , 01:56:58 SG #2 below 960 psig and decreasing due to return of feedwater. 01:57:05 SG #1 below 960 psig and decreasing. f,
^'
C - l::
Q SEOUENCE OF EVENTS 01:58 Tave restored to normal post-trip temperature. The cooldown had lowered RCS pressure to about 1720 psig. Operators manually started the HPI pump #1 in the piggy- , back mode (LPI pump 1 supplying the suction to the HPI , pump 1). A slight amount of water (about 50 gallons) was . injected. - 01:58:08 RCS loop #1 reaches a minimum pressure of 1716 psig. Loop #1 T-hot = 546.6 F; Tave =.546.2 F. 01:58:33 AFW #1 flow reduced to control OTSG 1evel. 02:01:13 AFW #2 flow reduced. 02:02:27 SG #1 returns to above 960 psig. 02:02:30 SG #2 returns to above 960 psig. 02:04 Plant conditions essentially stable. I Additional Comolications , *When the only operable source range nuclear instrumentation channel i - was energized, it failed to an offscale low value._ This left no. nuclear instrumentation on scale. All control rods were re-verified to be fully inserted. The operator initiated emergency boration.
*ATP #1 suction automatically transferred from the condensate storage tank (CST) to the service water system. The operator realigne l-4e--
to CST. a&The desuperheating spray c;:I r rr for the auxiliary steam system h*4-t--- 5.._: :;3 7;;7- ..w.....a... 7t'- allowed water into the main steam piping. When vacuum was restored and the MSIVs opened, the water slug damaged one of the main turbine bypass valves. Notes
- 1. Adequate subcooled margin was available throughout the transient.
The Reactor Coolant Pumps remained in operation. The Quench Tank contained the discharges f rom the PORV. " '--";/"i;5 "r:::ur: Irj;;;i;r ;;;!ir; cf - *** - - - crelin; :: 211 :ir::.
(-
- p , .,
SEOUENCE OF EVENTS
- 2. The above sequence of events is based upon combining infor-mation obtained from plant computer printouts and operator interviews. Due to time responses of instruments providing ,
input to plant computer systems and the inability to obtain the precise time of events from the operator interviews, , there is some potential ambiguity in the exact times; however, such ambiguity is not considered to be significant in under-standing the event. l W e
, 9*
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