ML20137A381
| ML20137A381 | |
| Person / Time | |
|---|---|
| Issue date: | 01/07/1986 |
| From: | Advisory Committee on Reactor Safeguards |
| To: | |
| References | |
| ACRS-T-1477, NUDOCS 8601140333 | |
| Download: ML20137A381 (300) | |
Text
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-877##
m ORGNAi ' r I V UNITED STATES
] NUCLEAR REGULATORY COMMISSION IN THE MATTER OF: DOCKET NO:
ADVISORY COMMITTEE ON REACTOR SAFEGUARDS REACTOR OPERATIONS SUBCOMMITTEE LOCATION: WASHINGTON, D. C. PAGES: 1 - 223 DATE: TUESDAY, JANUARY 7, 1986 -
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5463 01 01 1 knarysimons1 UNITED STATES OF AMERICA 2 NUCLEAR REGULATORY COMMISSION 3 ---
4 ADVISORY COMMITTEE ON REACTOR SAFEGUARDS S SUBCOMMITTEE ON REACTOR OPERATIONS 6 ---
7 Nuclear Regulatory Commission 8 Room 1046 9 1717 H Street, N.W.
10 Washington, D.C.
11 Tuesday, January 7, 1986 12 The subcommittee convened, pursuant to notice, at
/ 13 8:30 a.m., Jesse Ebersole, Chairman of the Subcommittee, 14 presiding.
15 [ ACRS Members Present:
16 J. EBERSOLS, Chairman C. MICHELSON 17 f 18 ! D. MOELLER l
19 D. WARD 20 C. WYLIE 21 G. REED 22 ACRS Cognizant Staff Member:
23 H. ALDERMAN 24
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5463 01 01 2 lkmrysimons1 NRC STAFF AND PRESENTERS PRESENT:
2 C. ROSSI 3 D. HERNAN 4 B. GALLO 5 V. PANCIERA 6 E. GREEMAN 7 S. MINER 8 H. SILVER 9 V. THOMAS 10 D. LYNCH 11 J. GIITTER 12 T. JOHNSON 13 S. LONG 14 M. CAMPAGNONE 15 R. SINGH 16 A. RUBIN 17 G. RIVENBARK 18 B. CLAYTON 19 B. NEIGHBORS 20 K. COOK 21 * * * * *
- 22 23 24 I
25 l i
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's_J PUBLIC NOTICE BY THE UNITED STATES NUCLEAR REGULATORY COMMISSIONERS' ADVISORY COMMITTEE ON REACTOR SAFEGUARDS TUESDAY, JANUARY 7, 1986 The contents of this stenographic transcript of the proceedings of the United States Nuclear Regulatory Commission's Advisory Committee on Reactor Safeguards (ACRS), as reported herein, is an uncorrected record of the discussions recorded at the meeting held on the above date.
No member of the ACRS Staff and no participant at C:) ~
this meeting accepts any responsibility'for errors or inaccuracies of statement or data contained in this transcript.
P j
3
5463 01 01 3 hm2rysimons 1 PROCEEDINGS I
2 MR. EBERSOLE: The meeting will now come to order.
3 This is a meeting of the ACRS Subcommittee on 4 Reactor Operations. I am Jesse Ebersole, Subcommittee 5 Chairman.
6 The other ACRS members in attendance are Messrs.
7 Carl Michelson, Dade Moeller, Glen Reed, Dave Ward and 8 Chuck Wylie.
9 The purpose of the meeting is to discuss recent 10 plant operating experiences. The Offices of Inspection and 11 Enforcement and Nuclear Reactor Regulation have identified 12 a number of current events for discussion with the
, 13 subcommittee.
14 Following discussion of these evente, a limited 15 [ number of these will be selected by the subconmittee for t
i 16 j presentation to the full ACRS during its 309tL meeting. l C
17 This presentation is tentatively scheduled for one and one-18 half hours, from 9 o' clock a.m. to 10:30 a.m., on Thursday, 19 January 9th.
20 Herman Alderman is the ACRS staff member for this 21 meeting.
22 The rules for participation in today's meeting 23 have been announced as part of the notice of the meeting 24 that was published in the Federal Register on December r- .
25 16th, 1985.
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5463 01 01 4 lknnrysimons1 It is requested that each speaker first identify 2 himself or herself and speak with sufficient clarity and 3 volume so that he or she can be readily heard.
4 We have recently received a report from Mr.
5 Michael Childers of Northeast Utilities on the Effects of 6 Hurricane " Gloria" on the Millstone Nuclear Power Station, 7 Units 1 and 2. The members will find a copy of this report 8 at your place on the table and you might review it.
9 I would like to ask the members to carefully 10 listen to each presentation and sort of rate it as a 11 candidate for the full committee presentation, and to the 12 best of your abilities to see what flavor, if any, common 13 mode failures you see ir. the individual events that we are 14 ! about the discuss.
I 15 With that I am going to turn the meeting over to 16 Ernie.
17 MR. ROSSI: Good morning. I am Err.ie Rossi, the 18 Chief of the Events Analysis Branch in the Office of 19 Inspection and Enforcement. I will introduce each of the 20 speakers as we go through the presentations.
21 But I would like to note that we have a number of 22 people with us who are here to aid in answering questions 23 that you may have or augment information on events that 24 they may be aware of, and I will tell you who those people 25 are.
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,5463 01 Ol' 5 barysimons 1 We have Vince Panciera of NRC Region II with'us.
2 We have Ed Greeman from NRC Region III. We have Alex 3 Bromery from the Office of Inspection and Enforcement. We 4 have John Stolz and Don Sells from the Office of Nuclear 5 Reactor Regulation.
6 We basically have about 10 presentations for you 7 this morning. They cover more events. Some of the people 8 are going to-talk a number of events that have occurred at 9 plants or in a couple of cases we have combined just some
'10
^
general problems into one presentation.
11 One of the things that we generally look for in 12 events is that we have been looking pretty carefully for r
. i
( 13' ' events that may have a bearing on various unresolved safety 14 issues that we know are within the agency. So you might 15 want to think about their relation to what is going on in-16 the unresolved safety arena as we go through these.
4 17 The first presentation will be given by Sid Miner 18 from the Office of Nuclear Reactor Regulation. He is going 19 to discuss four events that have occurred over the last two 20 or three months at Ranch Seco.
21 One of these events at Rancho Seco has triggered 22 the formation of an Incident Investigation Team similar to 23 the ones that were used on Davis Besse, which of course was J
24 completed last July, and one that is nearing completion on 4
25 San Onofre Unit 1.
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kncrysimons1 So he is going to give you some rather bare 2 details or bare information, a brief summary of what the 3 event involves. But at this point in time we would like 4 not to get into an in-depth discussion of that because we 5 want-to let the team do its job. When they are all 6' finished they will issue a report and at that point in time 7 you can decide what you want to hear from the team and 8 direct your questions at them.
9 So I guess we are ready to begin with with Sid 10 Miner on Rancho seco. Sid is the Project Manager in NRR 11 for this plant.
12 MR. MINER: As Ernie Rossi just mentioned, my name
) 13 is Sid Miner and I am the Project Manager in NRR for Rancho 14 Seco.
15 (Slide.)
- 16 This morning I am going to update you on an event i
17 that occurred on October 2nd,-which was discussed at your.
18 November 4th subcommittee meeting, and.then talk about a 19 pump, aux feedwater pump failure that was not related to 20: the October 2nd event but occurred shortly there afterwards 21 and_briefly talk about two events that have occurred since 22 the October event.
23 When we originally presented our story on the 24 October 2nd event, there was a loss of vacuum which we
() 25 thought initially triggered the reactor trip. A subsequent ACE-FEDERAL REPORTERS, INC.
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-5463 01-~01 7 knirysimons1 . investigation showed this wasn't true.
2 The reactor tripped from 15 percent power due to 3 high primary system pressure caused by a trip of both main 4 feedwater pumps. As a result, they had uncontrolled 5 cooldown of over 110 degrees Fahrenheit in 15 minutes.
6 The primary cause of the cooldown was the lifting 7 of the steam relief valve in one of the feedwater heaters.
8 It was actually the fourth point heater. And again the 9 vacuum loss didn't initiate the reactor trip nor effect the 10 resultant transient.
11 Now the main feed pump trip, the "A" pump was 12 tripped by a defective high-pressure trip switch. It is I 13 kind of a difficult thing to find. It was an intermittent 14 in the high-pressure trip and was something that was found 15 during the investigation.
16 The most probably, and they weren't exactly sure, 17 but the most probable trip of the feed pump was the 18 operating tripping'it. They were running it to 15 percent 19 power with water being fed to the steam generators by the 20 "A" pump. The "B" pump was was a minimum speed.
21 When the "A" pump tripped, the operator tried to 22 increase the speed of the "B" pump, but couldn't get it 23 increased fast enough. So he tripped the pump which then 24 got the aux feedwater system going.
A
's_) 25 At that particular time the aux feedwater pumps ACE-FEDERAL REPORTERS, INC.
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5463 01 01 8 lhmerysimons1, were started off of low pressure on the discharge sides of 2 the. main feedwater pumps, but the control valves were 3- opened by a separate signal that was taken off the turbine 4- on the main feed pumps.
5 So when the "A" pump tripped and the "B" pump was 6 at minimum speed, the auxiliary feedwater pumps- were 7 operating, but the valves weren't opened. But the operator 8 -knew that if he tripped the "B" pump he could open.the-9 valves and get aux feedwater into the steam generator. So 10 what they did is they replaced the high-pressure ' switch.
11 Since they had so much trouble trying to figure 12 out what caused both pumps to trip, they put some trip
() 13 monitoring equipment on the feed pumps to in the future be 14 able to diagnose trips a lot easier.
.15 And then they modified their aux feedwater 16 instrumentation system so that the same parameter would-17 start the pump and open the valves so there is actually low 18 discharge pressure on the main feed pump.
19 The uncontrolled cooldown was caused by the steam 20 pressure controller on the steam to the heater on low 21 power. When they started the steam was not available.
22 They used steam, or they sent steam to two heaters, the 2nd
, 23 and 4th point heaters to just keep the water hot. It is 24 called Pegging steam.
() 25 The Pegging steam is_taken off the main steam ACE-FEDERAL REPORTERS, INC.
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5463 01 01 9 lhmarysimons1 header. They have a reducing valve and a pressure 2 controller. And they had the pressure controller set very 3 close to the set point of the safety valve on the heaters.
4 So when the Pegging steam came on, the safety valve opened 5 and stayed opened. It was kind of a big valve that was the 6 main cause of the uncontrolled cooldown. So what they did 7 is they increased the set point of the safety valve on-the 8 2nd and 4th point heaters.
9 MR. MICHPLSON: Before you leave that slide, I s 10 think you said they were interlocking the main stcam water-11 low pressure with the auxiliary feedwater start. l 12 MR. MINER: On low discharge pressure on the main 13 feedwater system, both pumps. During our investigation we 14 asked the licensee ta tell if there was any single failure i
15 l in the ICS system that would isolate both feedwater pumps' 16 and close those valves and still not run the pumps back or 17 get the low pressure, and it takes tso failures to do that.
18 MR. MICHELSON: Is that safety grade?
MR. MINER: No. It is an integrated control 19 l s
20 system.
21 MR. MICHELSON: Auxiliary feedwater is ---
22 MR. MINER: Auxiliary feedwater is safety grade 23 except for those valves. Two failures would put you into 24 that situation.
25 MR. MICHELSON: Is that normally what the staff ACE-FEDERAL REPORTERS, INC.
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15463-01:01 10 lhucrysimonsl' considers acceptable?
2 MR. MINER: The aux feedwater system in the near 3 future, they are going to take initiation off the steam 4 generator level.
5 MR. MICHELSON: That is the reasonable way to do 6 it. Will that be backfitted to Rancho Seco?
7 MR. MINER: It is something that Rancho Seco has 8 been working on for the last five years.
9 MR.-MICHELSON: Ok'ay. Thank you.
10 MR. EBERSOLE: May I make a comment, Mr. Miner. I ,
11 have heard you mention a number of interlocks and other 12- features of this plant, each one of which tends to, in my 1
(x)-
y ..
13 view, to depreciate the reliability of the aux feed. pump 14' function. This is a B&W plant, isn't-it?
15 MR. MINER: Correct.-
16 MR. EBERSOLE: Can it feed and bleed?
g 17 MR. MINER: Yes.-
18 MR. EBERSOLE: So it has that recourse.
19 MR. MINER: Yes. ,
20 MR. EBERSOLE: In the course of looking at this y,
9 L 21 aux feed and main feed. system with-all-of these minor 4
-22 interlocking features that depreciate reliability 12 3 apparently,.has there been some sort of a PRA study and a 4
- 24. risk cost benefit? What is the action plan in a calendar n 25 context? You said five years. Five years is a hell'of a
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, trysimons 1 'long time.
'2 MR. MINER: What is the action plan for getting 3 the. safety grade control system on the aux feedwater; is J J
~
4 that.what you are asking?
'E 5 .Y MR. EBERSOLE: Yes.
4; 6 MR. MINER: During this particular event the gi 7 licensee has given us a schedule of two. refueling outages 8 'down, which we told them was unsatisfactory. I expect that 9 r, hey will have it in the next refueling outage which is'in 10 about'a year and a half, between a year and a year and a 11 half. That will give you the safety grade aux feedwater 12 and not the overflow. I think that will come later.
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MR. EBERSOLE: Well,1in the original evaluation of 14 -l thfis)configurationthatyoudescribedwastherean 15 l exhaustive effort to examine it and see what possible
- deficiencies there were in it and what the probable
<c 16 17 refiability or unreliability was, or was it just ignored as 11 were mostsof the secondary systems in those years?
~
18 19 ' MR. MINER: Oh, the secondary systems were mostly i!
20 ignored. LThey did a reliability analysis of the aux 21- fe,edwater system, and part of it was-the updated system 22 .about a year and a half ago.
23 MR. EBERSOLE: The one that didn't really exist.
24 y MR. MINER: The one that didn't really exist, J. 25 rig sti.
Lc
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- 5463L01 01 12 lhmerysimons.1 MR. EBERSOLE: That is characteristic of most 2 analyses, the ones that don't exist.
3 MR. ROSSI: Well, it was one that they committed 4 to resolve.
5 MR. MINER: Yes.
6 MR. EBERSOLE: How long ago was that?
7- MR. MINER: This has boon a sort-of chasing their 8 schedule down.for the last two or three years. Originally-9- it was supposed to have been installed in '83. The next 10 schedule was '86 and the last one was like '88. So now we
-11 are hoping to get it in '87. I think it will be put in in 12' '87.
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q- 13 MR. EBERSOLE: I see. Thank you..
~
14 ,
MR. MICHELSON: How did the staff finally decide 15 that the schedule was acceptable, particularly when you see 16 a picture of the way -- when do you call a halt and say you-17 have got to fix that?
18 MR. MINER: I think we have actually told them to 19 halt after this last October 2nd event which short of 20 flagged the deficiencies in the aux feedwater system. It 21 was at that point that we said no more, boys. You are
- 22 - going to get that'in there as soon as you can. They have 23 been on notice to get it in. It is a major modification, 24 'and I think we pretty well told them that much beyond the
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-5463 01101 13 harysimons11 '
get it.in.
2 MR. MOELLER: On the valves, the aux feedwater 3 valves will not open unless the main feedwater pumps are 4 down?
5 MR. MINER: No, no. These main feedwater pumps 6 can be running. When you get below 850 psi those aux
.7 feedwater valves open.
8 MR. MOELLER: Well, see, you have said up there 9 that the operator had to trip the "B" pump.
10 MR. MINER: Initially before they started up this 11' . time.the valve signal was taken off the electrohydraulic 12 system on the steam inlet valve. So you have two p)
",, 13 different signals. And by the wap, to start the pump it is 14 the safety grade signal. It comes off the discharge 15 pressure of the pump. At that time to open the valves, you 16 had to shut the pumps down.
1 17 , MR. EBERSOLE: May I ask then what is the 18 rationale? There seems to be no presence of slow, 19 deliberat. and careful evaluative thinking in the 20 application of that particular feature. From looking at 21 the generic aspects of that, it looks like this plant was 22 pasted together by such features as this, and that bothers 23 me in a broader context.
24 MR. MINER: That was part of the initial design,
() 25 and that gets way before my time. That particular feature ACE-FEDERAL REPORTERS, INC.
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5463~01 01- 14 hacrysimons1 .has been there since they originally designed the plant.
2 MR. MICHELSON: How can you have a safety grade 3 system that you can't start from the control room?
4 MR. MINER:' Oh, they can start it from the control 5 room.
6 MR. MICHELSON: .You said the operator had to trip 7 the pump in order to get it to flow.
- 8. MR. EBERSOLE:_ So it is an operator start. In 9 essence you are telling me there is a manual start on the 10 aux feed pump system.
11 MR. MICHELSON: Well, you have to wait for 12- pressure to come down on the non-safety system before it n
- ! ) 13 will flow.
14 MR. MINER: Let me put the aux feedwater system 15 up. I have got a sketch of that here.
16 (Slide.)
17 They actually had two sets of valves. We are talking about this pump here. This one here is an electric 18 19 drive and this one is a turbine drive. There are two sets 20 of valves.
21 (Pause while slide is adjusted.)
22 There are two sets of discharge valves. This is 23 the one we were talking about, the ICS. Here is a safety 24 grade valve.
( ) 25 MR. MICHELSON: Why did they have to trip the ACE-FEDERAL REPORTERS, INC.
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'5463 01 01 15 l b2rysimons 1 feedwater pump?
2- MR. MINER: You have got to have an SFAS. They 3 -didn't have an-SFAS.
4 MR. MICHELSON: Somebody can manually start that 5 system any time.
6 MR. MINER: Yes, you can manually start it.
MR. MICHELSON:
~
7 Well, why didn't he just manually 8 start it?
9 MR. MINER: He did.
10 MR. MICHELSON: Why didn't he leave his feedwater E 11 pump on and manual'ly start auxiliary feedwater just in case 12 for some reason ---
O) q, 13 MR. MINER: I am not sure. That is something I 14 can't answer. I am not sure that you can do that.
15 MR. MICHELSON: You can because otherwise you have 16 interlocked the safety and non-safety functions.
17 MR. EBERSOLE: How do you use pressure as a signal 18 of interest when it is really. level that counts?
19 MR. MINER: - Well, that is true.
20 MR. EBERSOLE: This is why I am getting back to
~21 the basic concepts.
22 MR. ROSSI: Sid, was the level signal planned to 23 be inst alled later on, or did that result because of this 24 event?
p)
(, 25 ,
MR. MINER: The level system has been part of the ACE. FEDERAL REPORTERS, INC.
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'5463 01 01 16 llhmarysimons1 ' design, the EPIC design all along.
2 MR. ROSSI: It j ust has not been ---
~3 MR. MINER: It just has not been installed.
4 MR. ROSSI: I think you have got to split off what
.5 their ultimate design was and the schedule for getting 6 there from what from they had at the time of the event.
7 The situation is that after Three Mile Island there were a 8 large number of things that needed to be changed, 9 especially on the older plants, and these had to be 10 scheduled and so forth. They.have an ultimate design that 11 they are moving towards.and they haven't gotten there yet.
12 MR. EBERSOLE: Well, TMI-2 was when, Ernie?
13 '
(_,; -
13 MR. ROSSI: Yes, but again.there were a large 14 number of changes that need to be put in.
15 MR. EBERSOLE: Here I see a pressure signal that 16 -is used to trip the need_for aux feed, and pressure has got 17 nothing to do with the parameter of interest which is level 18 to cover the tubes, and how can that persist these many-
' l' 9 years?
20 MR. ROSSI: Well, pressure does tell you when the 21 main feedwater pumps are no longer available. I think the 22 presumption was that as long as you have the main feedwater 23 available that you would get it into the steam generator 24 with a reasonably high probability.
) .25 MR. EBERSOLE: Don't you get back pressure from ACE-FEDERAL REPORTERS, INC.
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merysimons 1 steam in the boiler?
2 MR. ROSSI: I assume that there are check valves 3 there.
4 MR. MINER: There are check valves there that 5 'would prevent that. Actually if you have your pump idling 6 at low speed and you get below that 850 psi. That'is one 7 of the problems is that you can have the pressure in the 8 steam generator above the discharge pressure of-the pump 9 and you will be putting it in. So the aux feedwater pump 10 starts.
11 MR. EBERSOLE: Well, I am just sort of impressed-12 by the ragged nature of this design.
.!. o) 13 MR. MINER: This will be cleaned up. I think it 14 will be much better designed when they get the EPIC 15 installed. It will be a much cleaner design.
16 MR. HERNAN: Mr. Chairman, I believe there may_be 17 a representative'from the Sacramento Municipal' Utilities 18' and you might want to direct questions to them.
19 MR. EBERSOLE: Well, do we have any comments?
20 MR. MINER: I don't think there is. They didn't 21 indicate they were coming.
22 MR. EBERSOLE: I don' t blame them.
23 (Laughter.)
24 MR. MINER: There is somebody here from B&W, but I (W) s_ ' 25 don't know if he can comment on it or not.
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a 5463 01 01 18 kmcrysimons 1 MR. EBERSOLE: Any comments from B&W?
2 (No response.)
3 I rather think that this reflects on the B&W 4 design at large since they are permissive of this kind of 5 aux feed system.
6 MR. WARD: I don't know, Jesse. This is probably 7 in the balance of plant ---
8 MR. EBERSOLE: Nevertheless, the B&W people are 9 supposed to review and approve the attachments and 10 interfaces to their designs.
11 MR. WARD: Well, of course, the ACRS review it, 12 too.
13 MR. EBERSOLE: That was back in the days when 14 secondary systems weren't a matter of -- yes, sir.
15 MR. REED: Quite often we hear that Three Mile 16 Island happened a long time ago and thus the comment that 17 there are many, many things post-Three Mile Island that 18 have had to be backfitted.
19 However, thosb things should have been taken in 20 order of importance.
21 MR. EBERSOLE: Yes, sir, s
22 MR. REED: The most important thing, as we all 23 should understand now, is decay heat removal. This thing 24 that we are talking about here can jeopardize the path of 25 decay heat removal.
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a 5463 01 01 19 lhmorysimons 1 I heard the comment about bleed and feed, and the e 2 answer was yes. Are we sure that the bleed and feed 3 capacity is significant and relative to these kinds of 4 complex incidents of this integrated control system? Are g
5 we sure that that decay heat removal exists?
6 I think those should be top priorities and should 7 have been done years ago.
8 MR. EBERSOLE: In that connection, are the PORV's 9 qualified to sustain the environmental conditions 10 subsequent to initiating feed and bleed, or will they close 11 due to failure of the circuitry in the solenoid operated 12 a valves?
13 MR. ROSSI: I don' t believe they have been 14 qualified. I think the experience has been that they have 15 failed to open now and then, but I don't think they are 16 actually included in the equipment qualifications program. l 17 MR. EBERSOLE: They do require applied voltage to 18 hold open, don't they?
19 MR. ROSSI: And I don't know to what extent --
20 yes, I believe they do -- but I don't know to what extent 21 they can use feed and bleed through the safety valves on 22 this plant.
23 Do you happen to know, Sid?
24 MR. MINER: We don't know.
N 25 MR. ROSSI: It depends on the head in the pumps.
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5463'01 01 20 hmarysimons1 MR. MINER: Yes, the pumps are high head and they 2 could raise the pressure up.
3 MR. ROSSI: I don' t know whether that is 4 envisioned or not.
5 MR. EBERSOLE: To what pressure can they raise 6 compared to the pressures of the PORV's and the safeties on 7 the primary side?
8 MR. MINER: They have three pumps, HPI pumps, one 9 of which is used as a make-up pump. At the full system 10 pressure, the HPI. pumps can go into full system pressure.
11 MR. EBERSOLE: Full system pressure, what is the 12 set point on the safeties?
() 13' MR. MINER: What is it, about 2250 or 2400?.
14 MR. ROSSI: The safeties are generally around 15 2500, and I believe that is probably what they are.
16 MR. MINER: 2500. And you have got a pump that is 17' what, about 2,000 pounds delta P, and they can usually go 18 20 percent over. So I would imagine the pump would be able 19 to take it.
20 MR. EBERSOLE: I think it would be. prudent to 21 confirm, as Glen says, that you can in fact feed and bleed, 22 including consideration of the failure of the PORV valves 23 if they are not qualified to survive the environment, you 24 know, which is a hot containment.
() 25 MR. REED: And in fact to that end to schedule for ACE FEDERAL REPORTERS, INC.
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5463 01 01 21 lhuntysimons1 an upgrading of the process.
-2 MR. EBERSOLE: Yes, right. All of these should be
.3 - poured into the common pot of that schedule to fix it.
4 MR. REED: I might say in my opinion there has 5 been'overfocusing ever since Three Mile Island on the 6 -operator aspects of the improvements.
7 MR._ESERSOLE: Well, that is the cheapest.
8 MR. REED: And the design vulnerabilities of 9 particular-concepts have not been focused on enough.
'10 MR. EBERSOLE: That is the expensive part. That 11 is why that has happened.
12 MR. REED: Well, it may relate to designers saying
() 13 they never make mistakes.
14 (Laughter.)
15 MR. EBERSOLE: I would like to ask the reporter to 16 make particular note of these observations and we will be 17 prepared to discuss this at the full committee.
18 MR. ROSSI: I would like to make one other comment 19 on this particular event though that I think the ultimate 20 problem has been with rapid cooldown rather than the 21 ability to get rid of the decay heat.
22 Now it could have been the other way around.
L 23 MR. EBERSOLE: Right. It just exposed the latter l
t 24 broblem.
I () 25 MR. ROSSI: Yes. So we also have to worry about l
l
[
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e 5463 01 01 22 h rysimons 1 the problem of getting all this feed water in there and 2 cooling down too rapidly. You know, you have got the 3 competing priorities, and on this particular one that 4 turned out to be an ultimate problem.
5 MR. REED: Just a minute, Mr. Rossi. I would like 6 to still state again that too rapid cooldown on a B&W 7 concept can lead to thermal block and therefore the 8 interruption of natural circulation, and it could just as 9 well had a loss of AC coolant.
10 MR. ROSSI: Oh, I understand, and I am not trying 11 to, you know put too low a priority on the decay heat 12 removal. I am just point out in this vvent that it turned 13 out to be the other problem. We fully appreciate the l
14 importance of getting this system to be safety related and 15 a totally single failure proof system and also l 16 appropriately addressing the excessive cooldown as well as l
17 the decay heat removal part.
l 18 MR. EBERSOLE: In that connection while the 19 diagram is up there, I call the members' attention to the 20 fact that you see no main steam isolation valves.
l 21 MR. MINER: This isn't a primary loop, but there 22 are no main steam isolation valves. That is true.
23 MR. EBERSOLE: So what you see here again is 24 another flavor to the same design omission or an inability
) 25 to stop blow-down into the secondary from any valve thai.
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'5463 01 01 23 lhmcrysimons1 might open in the secondary of which there are many. So 2 the challenge frequency is obviously quite high compared to 3 the plants that do have the main steam isolation valve. So 4 the design at large I think needs to be sort of looked at.
5 Any comments from the members here? We have to go 6 on to the others or we will never get out of here.
-7 (No response.)
8 MR. MINER: Let me get to the second part.
.9 (Slide.)
10 An unrelated event, they had an aux feedwater pump 11 failure. The aux feedwater pump -- the. thrust bearing 12 failed because a slinger ring was installed improperly. As I a matte r of f act, it was moved way out of place and it
(> 13 14 wasn't doing anything. They repaired the bearing and made 15 sure the slinger ring was back in place and they made an 16 endurance test of the pumps. Then they went through all 17 the rest of their safety grade pumps to make sure the same 18 thing didn't occur or hadn't occurred on them.
19 MR. EBERSOLE: Now wait a minute. They went 20 through all the rest of them and did they do any 21 alterations?
22 MR. MINER: No. They were all in place. They 23 basically examined them to make sure they were all in 24 place.
) 25 MR. EBERSOLE: I am thinking about the problem of t
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5463 01 01 24 kunry'simons'l touching all of your resources at one point in time and 2 messing them all up, which has been ---
3 MR. MINER: Well, they just looked at.them.
4' Actually you could take of f the end plate and take a look 5 and make sure it was okay.
6 MR. EBERSOLE: Okay.
7 MR. MINER: And that is what they did. I think 18- 'there was something like four or five pumps to look at.
- 9 MR. EBERSOLE: You know what I am talking about.
10 MR. MINER: Oh, yes. When you start messing, you 11 can make them all wrong.
12 MR. EBERSOLE: Don't touch esarything at once.
O
(_) '13 MR. MINER: No, they didn't have 'o touch them.
'14 They just had to look'at them.
15 MR. MICHELSON: When did this failure occur?
16 MR. MINER: I think it was something like October 17 7th, or about a week afterwards.
18 MR. MICHELSON: A week after the event took place?
19 MR. MINER: Yes. They were down and they were 20 running their main feed pumps off of auxiliary boilebs, and 21 when the auxiliary boilers failed, the aux feedwater pumps 22 came on and ran for about an hour or two. And at the end 23 of that hour or two they noticed this pump was hot. So 24 they shut it down. They when they got the boilers back on,
() 25 they shut it down and went in and found out what made it so ACE-FEDERAL REPORTERS, INC.
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5463 01 01 25 knarysimons 1 hot and they found the failed bearing.
2 MR. EBERSOLE: I would sort of call that a 3 standard piece of malpractice. There is nothing funny 4 about it unless the paper record showed everything ---
5 MR. MINER: No. The pump had been rebuilt early 6 in operation and had been examined around 1978 and they 7 couldn't pin down when this took place. Yes, I agree with 8 you on that one.
9 MR. WYLIE: Do you know whether or not they ran a 10 ready for in-service test after they rebuilt the pump?
11 MR. MINER: Yes. I think you have to run them 12 like 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />.
13 MR. WYLIE: And they didn't notice anything then?
14 MR. MINER: No, no. It ran real well.
15 MR. EBERSOLE: So the time test is not long 16 enough. That is at least something you can get out of it.
I 17 MR. MINER: A 72-hour time test?
18 MR. EBERSOLE: Yes.
19 MR. ROSSI: Well I guess if I had to put my effort 20 one place or the other, I would put it on the OA of putting 21 this ---
22 MR. MINER: That is right, the preventative 23 maintenance type of thing.
24 MR. ROSSI: The testing is important, but I don't 25 that we will over get a test that will find ---
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5463 01 01 26 hmnrysimons1 MR. MINER: It is interesting that ---
2 MR. ROSSI: The gross ones you have got to decide 3 on sometime, but I think the real important thing is that 4 the maintenance and rebuilding and all that hea to be done 5 considerably more carefully throughout the industry than is 6 being done today.
7 MR. MINCR: I think one could say that there was 8 kind of a OA failure.
9 MR. WYLIE: But I noticed in some of the other 10 reports like the diesel generator at Catawba had bearing 11 failures after running eight hours full load on that after 12 a rebuild and then they had a bearing failure and found 13 l it. They would have never found that bearing if they had 14 just simply run the normal testing. The only thing it 15 points up is these tests after rebuild are im po r ta n t , that, 16 they have got to be long enough until you pick out the 17 defects in the equipment.
18 MR. ROSSI: I would like to state again a point 19 that I wanted to make at the start of this thing, and that 20 is when we pick these events we bring you events that 21 really happened on real plants. And I think one of the 22 important things for us all to do is to tie into other 23 issues within the agency that are going on, and clearly 24 there are losues involving maintenance and how well it is
) 25 done and there is also a lot of discussion wit hin the ACE-FEDERAL REPORTERS, INC.
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P 5463 01 01 27 mnrysimons 1 agency about what is the appropriate kind of testing. So 2 these are tied.
3 MR. WYLIE: But the point I was making is that the 4 post-maintenance testing is important, and you agree with 5 me on this ---
6 MR. ROSSI: Oh, absolutely, and I think everybody 7 here agrees that post-maintenance testing ---
8 MR. WYLIE: It has to be severe enough to pick out 9 those things.
10 MR. ROSSI: It has got to be appropriate to ensure 11 that the maintenance that has been done has a high 12 probability of having been done correctly.
13 MR. WYLIE: True.
I 14 HR. ROSSI: And you have really got to do both.
15 You have to have the OA on doing the stuff right in the 16 first place, and then to the best of your ability you run 17 tests that are really going to prove that the equipment 18 will do the job that it is supposed to do.
19 MR. WYLIE: If the checker on OA had been on his 1
20 ' toen he would have caught the fact that that slinger ring 21 was not in there right.
22 MR. ROSSI: And the training of the people doing 23 the work in the first place, too. All of these are 24 important.
~
25 MR. MINER: I think there have boon problems in ace-FEDERAL REPORTERS, INC.
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~ harysimons'l the OA' system of Rancho which is being ~ upgraded. They are 2 taking a. lot ~more _ care with the OA. I'would say in the era 3 of 1978 when this was last looked at there wi.s probably 4 poor OA.
5 MR. MICHELSON: When was the bearing actually 6 'epaired?
r
.7 MR. MINE1: During this last down in October.
8 MR. MICl4ELSON: It had-just been repaired during 9 the first ---
10 MR. MINER: Oh, no. The last time the pump had 11 been looked at was_in 1973.
12 MR.-flICHELSON: The bearing you said was repaired
- d. 13 was the ---
, 14 MR. MINER: Just.recently, fes, and that was in 15 October.
16 MI;. MICHELSON: And it fa! led in' October. I 17 PR.- MINER:' No. After it failed. It was repaired 18 after*it failed. They repaired it after it failed.
19 M R. MICHELSON: And at that time the ring was pat-20 in backwards.
21 MR. MINER: The last f.ime they looked at it ---
22 M R. MICHELSON: Let te read you a statement. It 23 in the third bullet.
24 MR. MINER: Okay.
25 MR. MICHELSON: "Baaring repaired with slinger r
- l. ACE-FEDE1;AL REPORTERS, INC.
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5463.01:01 29 lhmarysimons.1 rings properly installed." Now when was that done?
2 MR. MINER: In October sometime before they 3 started up in November. It was done in October, after _
4 October 7th.
5 MR. MICHELSON: Okay. And the failure occurred in G November.
7 MR. MINER: On October 7th.
8 MR. MICHELSON: Wait a minute.
9 MR. MINER: Okay. Let me go through it again.-
10 The pump got hot, they looked at it on October 7th and they 11 found a slinge ring out of place. They pulled it apart 12 and repaired it, and that is repaired. The last time the n
(_) 13 pump had been looked at previous to that, the last time it 14 had been. opened previous'to that was in 1978. So it had 15 run for six to seven years with a slinger ring out of 16 place.
17 MR. MICHELSGN But the slinger ring didn't cause 18 the failure of October 7th?
19 MR. MINER: We think that is what caused it.
.20 MR. MICHELSON: But then it was installed 21 backwards twice.
22 MR. MINER: No, once. It was on backwards and it 23 was out of place.
24 MR. ROSSI: It was in incorrectly since 1978 or i) 25 oven longer and it took all that time before it finally ACE-FEDERAL REPORTERS, INC.
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5463 101.01 30 hatrysimons1 resulted in the failure.
2 MR._MICHELSON: And what was the longest run since 3 1978 on the turbine? It must have run for-days.
4j ' M )R. MINER: Oh, no. This is the aux feedwater 5 pump. My guess is all-told they had 100' hours on it.
6 MR. MICHELSON: Well, it is used normally for 7 shutdown.
8 MR. MINER: No. They start up and shut down'the
-9^ main feed pumps.
10 MR. MICHELSON: Okay. Thank you.
11 MR. EBERSOLE: Any further questions?
12 MR. ROSSI: I think you have more on other events.
](,, 13 MR. MINER: Yes.
14 MR. ROSSI: Ek> why don' t you go on.
15 MR. MINER: Let me -just briefly go through one 16 other event.
-17 (Slide.)
18 On December the 10th they had another reactor trip 19 at 91 percent power, and this occurred when they were 20 transiting from manual to automatic. What happened was 21 that in the transfer all of the sudden the main feedwater 22 flow increased.
23 The operator in looking at the flow meters 24 returned the control of the main feed flow to manual, and I) 25 in looking at the meters, the "A" meter responded and the ACE-FEDERAL REPORTERS, INC.
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r 5463 01 01 31 llhmsrysimons1 "B" meter hung up. He didn' t recognize the fact that the 2 "B" meter was hung up and he thought the flow hadn't 3 reduced. So he was reducing it further and got a high-4 pressure scram.
5 Again the safety valve on this 4th point feedwater 6 opened, and it was due to a 20 percent overshoot in the 7 controller. With the safety valve higher, there was a 20 8 percent overshoot. They diagnosed it right away and shut 9 it off before they got an overcooling. They manually shut 10 off the steam to the header and the plant stabilized 11 without anything except a cooldown and pressure transient.
12 l So this time they want back in and they reset the 13 controller down. I think it was down from something like 14 ; 135 pounds to about 60 to 70 pounds, i
15 l MR. EBERSOLE: When he reduces the flow further, l
16 what correlation does he use to verify that the flow meter 17 is working or not working?
18 MR. MINER: He could have looked at some other {
19 instrumentation. They have these two recorders that they 20 look at when they adjust flow, and he just looked at those 21 two. He didn't look at any others.
22 MR. EBERSOLE: Well, this is a superheat boiler, 23 isn't it?
24 MR. MINER: I beg your pardon?
25 MR. EBERSOLE: It is a superheater design? It is ACE-FEDERAL REPORTERS, INC.
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5463'01 01 32 lhmrysimons 1 a B&W design.
2 MR. MINER: It is a B&W design.
3 MR. EBERSOLE: What besides flow does he look at?
4 MR. MINER: I think when he is adjusting flow that 5 is all he looks at.
6 MR. EBERSOLE: He looks at flow to determine 7 whether he is getting enough feedwater, and again we see 8 flow rather than a level.
9 MR. MINER: There is level instrumentation there 10 that he could look at and he didn't look at it.
11 MR. EBERSOLE: Okay.
12 MR. MINER: I understand that in this type of 13 transient acts real fast.
14 MR. EBERSOLE: Well then, is he told to look at 15 them? What are his instructions? Does he just freely look 16 at one parameter and manipulate the control on that and not 17 make correlative observations?
18 M R. MINER: Apparently that is what this operator 19 did.
20 MR. EBERSOLE: Is that in the standard manual of 21 instruction or was it a unique error on his part?
22 MR. MINER: I am not sure. I know the manual now 23 tells them to look at oth3r things. I don't know what it 24 was before.
s 25 MR. EBERSOLE: Well, after all thene years ACE-FEDERAL. REPORTERS, INC.
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'5463-01 01 33 llhnarysimons1 something should be done if that isn't in the manual.
2 MR. MINER: I agree. It was pure and simple an 3 operator error. There are instruments right alongside that 4 he could have looked at.
5 MR. EBERSOLE: Well, I am glad-there is a SWAT 6 team on Rancho Seco. I think it is needed there.
7 MR. ROSSI: Sid, weren't the procedures changed as 8 a result of this event?
9 MR. MINER: I am not sure which ones they have 10 changed. I know the guys were pretty 5/oll instructed to 11 start looking at other instrumentation, but I didn't get 12 into exactly what procedures were changed.
()- 13 MR. EBERSOLE: Any further questions here?
14 (No response.)
15 MR. MINER: Just let me briefly touch on the other 16 one. This is the one that Ernie had mentioned there was an 17 investigative team out there.
18 MR. EBERSOLE: We are still on schedule.
19 (Slide.)
i 20 MR. MINER: The plant was at 76 percent power, and .
l 21 this time they got an ICS block, power failure in the ICS 22 and they lost the ICS.
I 23 A lot of valves changed position and they got a 1
24 reactor trip'and about a 200 degree -- I think the last I
() 25 heard of it, it was 180 degrees in about 24 minutes, in ACE. FEDERAL REPORTERS, INC.
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1 5463 01 01 34 llkmarysimons 1 that range, and we have this incident investigative team at 2 the site right now looking into this transient.
l 3 f1R. ROSSI: There were some other problems with 1
4 equipment and so forth during this event, and as a result l 5 of the complexity of it and the number of apparent 6 problems, the NRC originally sent an augmented inspection 7 team out to the site with irstructions to start their work 8 with formal interviews and transcripts and that kind of 9 thing so that if it turned into something that had to be 10 upgraded into a full-fledged incident investigation team, 11 all the records would be there.
12 After the augmented team had been there for I 13 guess a couple of days, on that order, and I don't know the 14 exact time the decision was made to go with the full-15 fledged incident investigation team similar to the one that 16 went on Davis-Besse. So we will get that report from them 17 j probably in a month or so, and we will be prepared to come I
18 j down and give you a full presentation on their findings on 19 that event and the causes associated with it.
i 20 MR. REED: Mr. Chairman, I am worried about these 21 four events in three months. One Babcock and Wilcox 22 reactor event and of course these are all piled on top of 23 Davis-Besse, and all these four events in my analysis, 24 quick analysis, seem to present the opportunity to 25 jeopardize the removal of decay heat and to have to trip ACE. FEDERAL REPORTERS, INC.
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'5463 Ol'01 35 lhmarysimons1 either by blockiro thermal circulation, by overfill ~or by 2 low inventory on the secondary side by this system or by 3 the whole~ complexity of the integrated control system.
4 Quite frankly, I think between auxiliary feed 5 failures, integrated control system failures and the 6 complexity, for this concept to rely on auxiliary feed 7 paths and steam generator paths to decay heat removal is 8 putting yourself in jeopardy in the long term. i 9 There'ought to be, and that is why I asked the 10 question about bleed and feed, and I think you caught it, 11 there ought to be very close follow-up to see if 12 alternative techniques need to be taken.
3 ). 13 Now I happen to know there are some reactors that 14 have additional heat removal, but apparently Rancho Seco 15 doesn' t and Davis-Besse doesn' t.
16 MR. MINER: This is not the same as Davis-Besse.
17 These HPI pumps are full discharge pressure pumps.
18 MR. REED: Well, I wasn't focusing on bleed and
-19 feed.
20 MR. MINER Okay.
i 12 1 MR. REED: I am focusing on the issue of decay I 22 heat removal. Normally the path is to go through the steam l 23 generators which rely on about eight other systems. I l
l 24 think we have to make sure that the B&W system is capable
() 25 of taking care of the issue after about 10 or 15 minutes of ACE FEDERAL REPORTERS, INC.
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5463 01 01 36 kanrysimonsI loss of control on one of the feedwater inputs to the steam 2 generators.
3 MR. EBERSOLE: Isn't this plant comparable to ANO-4 l?
5 MR. MINER: Yes.
6 MR. EBERSOLE: And didn't they take the somewhat 7 prudent position of putting on a valve on the primary 8 system to permit what Glen is talking about?
9 MR. ROSSI: I am not familiar with that particular 10 change.
11 MR. EBERSOLE: I believe they have a two-inch 12 valve or bigger, which is a straight common valve.
13 MR. WARD: Jesse, I think you are thinking of ANO-14 2.
15 ! MR. EBERSOLE: No, I am thinking about ANO-1.
16 i MR. WARD: I mean the unit.
I 17 MR. EBERSOLE: The B&W unit, the first unit.
18 MR. MINER: It is ANO-1.
19 MR. WARD: You are thinking about che CE unit.
20 MR. EBERSOLE: It is a CE unit. You are right.
21 MR. WARD: It is ANO-1 and 7..
22 MR. EBERSOLE: You are right, ANO-1 and 2. I am 23 mixing these up.
24 MR. ROSSI: Well, we on the staff recognize the 25 seriousness of the problems which is why the events are en ACE-FEDERAL REPORTERS, INC.
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, 5463 01 01- M h:rysimons'l the: list to~ talk to you about. We have the incNent (w 2 investigation team, and the recent reorganization in NRR 3 ' has allowed people to become exper.s ba'sicall,y,in one type 4 2,,
4 and ensure that there is a good relation of problems with i
e 5 one plantJto others, and then of course we have unresolved Il \
l 6 safety issues, like there is .one. on decay heat reinoval.- I c~.
7 don't know what.the status of thatjo.ne is right nowf b'ut '
t .
8 there are a number of things goingiot'to address thsse and 9 we are trying to make sure ,the sixpgiencegets used. '-
10 MR. ROSSIt I understarid all that, and all I am
,3 6 11 repeating here again is, $s i said in the Davis;Besse '
s 12 incident, I will have great' interest' in.,yogar investigation 13- team's report and whether or not4 they arrivo s at what -- and 14 I am going to be prejudiced here -- what I think are the l 15 root causes, the real root causes of these incidents on B&W
! i j 16 plants.
u 17 MR. ROSSIt I understand.
18 MR. EBERSOLE: Ernie,.that team was sent there 19 basically because of one incident and not all of these, 20 right?
21 MR. ROSSI: That is true, but we did have s 22 augnented teams go out on the first two. We have two 23 levels of incident investigation. We have the incident 3'
' , C ~
24 investigation team which addresses what the NRC considers 25 to be the bigger events, and then we have the augtnented i
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5463 01 01 38 lhmzrysimons1 ones where we augment a region inspection with people from 2 headquarters.
3 Now these first two events received a lot of 4 attention by headquarters people, and maybe you can 5 describe a little bit more all the people that went out and 6 looked at this.
7 MR. MINER: We had an augmented team that went out 8 that included I&E, myself and NRR. We had a management 9 team that followed up on that that included the Directors, 10 Dick Vollmer and Beralia, and the Regional Administrator 11 that sont out there and met with them on the first two 12 events where we are talking about the pump and the pump 13 failure and the first trip.
14 MR. EBERSOLE: So that this is sort of a generic 15 examination being made at t:he plant.
16 MR. MINER: Yes. It got a lot of attention and 17 there was a great deal of review made on the thing.
18 Actually the plant was down for about a month while we were 19 reviewing and evaluating. They themselves did an in-depth 20 root cause analysis on things and it was very thoroughly 21 evaluated.
22 MR. MICHELSON: Are there reports that we can read
. 23 from the augmented teams?
\
24 MR. MINER: There is an SER in the system now that 25 I think has not been quite completed.
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5463 01.01 39 !
3llhurrysimons1 MR. MICHELSON: That is an SER dealing with each
., _' 2 of the previous events or ---
- l ,
3 MR. MINER: No. Just this October event, October l
4 2nd event.
t 6.j "
- ( ,.
5 f MR. MICHELSON: Well let me ask as a general 6 principle, the augmented teams, are they required to submit 7 some kind of a formal report?
8 MR. ROSSI: The Office of Inspection and 9 Enforcement just issued for comment procedures to all of
- r b;
-10 the regions for how to de the augmented inspections.
/L+ 11 Basically.the region will generally have to lead in that, 12 and there is a requirement of a report which will be done 13
-(s) basically by the region. That procedure was issued I 14 p believe sometime in the'last month for comment to the 15 region and also for interim use.
,- 16 So we are also starting to use the procedure at
~
ly'i. 17 'this point, and as a matter of. fact if you are interested,
[' ,
18 I can get you copies.
MR. MICHELSON: Yes,'I would like to see it. So I
}9
/ 20 guess the answer to my question is yes.
Ng
~
21 MR. ROSSI:. Yes, there is a report. -One of the 22 things that we.are trying to do with all of the 23 investigations of events is do them more systematically and 24 make sure that what was done is documented and we have two 25 levels.
5,J ACE-FEDERAL REPORTERS, INC.
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5463 01 01 40 llkmnrysimons1 I would like to say one other thing on events 2 analyses. The Office of Inspection and Enforcement is 3 directing more and more attention now to looking at series 4 of events that occur on one particular plant and not just 5 what you see in this event, but what have we seen in the 6 last six months to a year on a particular plant that might 7 tell us where we ought to better direct our inspection 8 program plant specifically.
9 So that effort is going on also. So we pick up 10 series of events like on Rancho Seco that indicate that 11 there may be some more fundamental problems and that is 12 being used by the NRC management to direct resources, 13 especially in the Office of Inspection and Enforcement. I 14 can speak more about what is going on there than NRR right 15 now, but NRR I think is going through similar kinds of 16 things. I think there has been considerably more emphasis 17 on that since Davis-Besse.
18 MR. REED: If AELD just focuses on series of 19 events or sequential events at one plant, think about the 20 concept of a series of events, failures and malfunctions on 21 a concept and think about design.
22 MR. ROSSI: We also have the cut of how generic 23 are the events also, and we try to feed that information 24 back into the unresolved safety issues. We issue bulletins m
25 and of course the notices the the most common thing we do ACE FEDERAL REPORTERS, INC.
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5463 01 01' 41 lhmnrysimonsl' because we can do that very quickly to make sure that 2 everyone in the' industry is aware of what has occurred.
3 We are in the process on this latest Rancho Seco 4 event of .trying to issue an information notice that gives i 5- the bare essentials so that other people within the 6 industry will know what happened and hopefully will take-7 initiative to do what they can to prevent a similar thing 8 :
on their plant.
1 9 MR. MICHELSON: Is there an owners group for B&W 10 for feedwater?
11 MR. MINER: There is an owners group, and the 12 owners group is meeting with us tomorrow on this ICS ---
.p) g_ 13 MR. MICHELSON: Is the owners group devoted just 14 to-this subject, or is it a broad one?
~
15 MR. MINER:- The one that is meeting tomorrow is a 16 reg. response, a B&W reg. response group.
17- MR. MICHELSON:- They haven't set up-an ad hoc 18 group to look at -auxiliary feedwater?
19 MR. MINER: They do have a group set up to.look at L20 ' improving the reliability of main feedwater systems to 21 y reduce challenges to the aux feedwater system.
22 MR. MICHELSON: Is that only looking at auxiliary
-23 feedwater or just main feedwater?
-24 MR. MINER: John, are they looking at aux
() 25 feedwater, too?
I l
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5463 01 01 42 kmnrysimons1 MR. SOLTZ: They are looking at everything. They 2 are looking at the total picture of main feedwater, 3 auxiliary feedwater, and they were requested and plrening 4 to meet with us tomorrow at 1 o' clock to review 5 specifically the implications of the Rancho Seco event.
6 MR. MINER: Is that the same group, John, the reg.
7 response tomorrow, isn't it?
8 MR. SOLTZ: The reg. response group.
9 MR. MINER: But there is also an owners group ---
10 MR. SOLTZ: In addition to thel, the owners group 11 has a special effort on main feedwater and auxiliary 12 feedwater to improve overall reliability.
) 13 MR. EBERSOLE: To what extent does the absence of 14 main steam isolation valves in essence degrade the turbine 15 driven pumps since I gather you don't have any steam 16 pressure to drive them?
MR. ti I N E R : They wouldn' t degrade them at all 17 l 18 because they would be upstream of main feed anyway, 19 , wouldn't they?
20 MR. EBERSOLE: But there are no MSIV's.
21 MR. MINER: Yes, I know. But the turbine stop 22 valves are upstream. So it wouldn' t degrade them.
23 MR. EBERSOLE: Oh, I am talking about if you have 24 a condition such as you had here, which was secondary 25 blowdown with no means to intercept it.
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~5463 01'01- 43 llhmarysimons1 MR. MINER: Oh, yes, there is. There is a valve 2 on the line and they just go and shut the valve.
3 MR. EBERSOLE: Where?
4 MR. MINER:. Right at the main header.
.5 MR. ROSSI: I think the situation on this plant-6 without MSIV's is that they have to go-in and do individual 7 valve isolations depending on where the problem-is, and 8 - there is'no' question that that increases'the probability of 9 having some sort of failure.
10 MR. MINER: There are a limited number of valves 11 that take off from the system beyond the turbine stop 12 ' valves. All the intercept' valves and everything else is O: 13 8ev #a ** e-
. 14 MR. EBERSOLE: I know, but what I am saying is I 15 gather this plant can completely depressurize because it 16 has no main steam isolation valves.
17 MR. MINER: If.the. turbine stops stay open, yes.
.18 MR. EBERSOLE: No, I am talking about just the 19 bypass valve.
20' MR. REED: Steamline rupture.
- 21 MR. EBERSOLE:- The bypass valve.
'22 MR. MINER: I have looked at other B&W plants.
23 The-turbine bypass valve and the ADV's, the atmospheric 24 ; dump valves are all upstream of the MSIV.
-() 25 MR. EBERSOLE: There is no MSIV.
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2 MR. EBERSOLE: I am talking ~about this plant.
l 3 MR. MINER: Okay. This plant, the turbine stop 4 ' valves are seismically qualified.
- 5 MR. EBERSOLE: I know, but the bypass. valves can 6 .be opened or any number of other valves.
7 MR. MINER: That is true.
8 MR. EBERSOLE: And when that happens ---
, 9 MR. MINER: 'Then you have to go andt close them.
- 10. MR. EBERSOLE: You have got to go and-individually 11 close them.
12 MR.. MINER: Yes.
13 MR. EBERSOLE: In the interval, and this is a very 14 hot plant because it needs water instantly, in the meantime
.15 you lose feedwater from the turbine driven aux feeds. You 16 are then left on nothing but the electrics; am I correct?
- -17 MR. MINER: -They have never gotten into the-
.18 - situation where'they completely depressurize the ---
19 MR. EBERSOLE: Well, I thought they did in
- - 20 connection with this PTS problem they had.
21 MR.-MINER: The' pressure ran down to maybe -- and 12 2 you are talking about the primary system pressure. The i- secondary system pressure might have gone dow'n to ---
23 4
24 MR. EBERSOLE: Yes, but it was a little valve that l() 25 opened. Suppose it was a blocked open main steam-isolation ACE-FEDERAL REPORTERS, INC.
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5463 01 01 45 lhm":rysimons1 valve. No, I don't mean that. Suppose it was a blocked 2 open bypass valve, which is 25 percent or something?
3 MR. MINER: They have had those, the blocked 4 open. They have had isolation valves open up, yes.
5 MR. EBERSOLE: Does that depress the ---
6 MR. MINER: It maybe goes down to about six or 7 seven hundred pounds by the time they isolate them. They 8 have time to isolate them.
9 MR. EBERSOLE: If they can.
10 MR. MINER: They have in the past been able to 11 isolate them.
12 MR. REED: I think what Jesse is saying is don't 13 place too much reliability ---
14 MR. EBERSOLE: --- on the turbine pump.
15 l MR. REED: --- on the steam driven auxiliary 16 ; boiler feed pump as being an available device to provide f
17 feedwater because the design doesn't support that.
18 MR. EBERSOLE: Exactly, right.
19 MR. MINER: But the MSIV's wouldn't help on that 20 particular one because the MSIV's will be downstream of it 21 anyway.
22 MR. HERNAN: Sid, can't both aux feed pump valves 23 be electrically driven?
24 MR. MINER: Well, he is not talking about the 25 valves. He is talking about the turbine driven pumps.
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'5463 01 01 46 ,
lhmarysimons-1 MR. HERMAN: Oh, the turbine pumps. I am sorry.
2- Is one pump dual. turbine?
3 MR. MINER: One is dual turbine drive, th'e turbine 4 electric drive,- and the other one is electric drive. So 5 they.can run both of them off of electric and off different 6 diesel generators and off different buses.
'7 MR.-ROSSI: This particular plant has basically 8 two electric driven or two auxiliary feedwater pumps that 9 each is capable of being electrically driven.
10~ MR. MINER: Both have electric drives on them.
11 MR. ROSSI: And one of them.can also as an l2'
~
alternative be driven with steam, g):
( 13 MR. MINER: One the second one the steam is a 14- -preferred drive.
15 MR. EBERSOLE: So what we have done is degrade the 16 turbine driven pump to some degree.because they haven't the 17 main' steam isolation-valves.- Okay. Can these be driven by J
18 diesels?
19~ MR. MINER: Yes, they are off the diesel, off the-20 emergency bus.
21 MR. EBERSOLE: Hc d many diesels are there?. '
1 22 MR. MINER: They have two diesels right now and 23 they are installing two more.
24 MR. EBERSOLE: Okay.
1
() 25 MR.-ROSSI: Now recognize Davis-Besse is not in l
1 ACE-FEDERAL REPORTERS, INC. -
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5463 01 01 47 llhmarysimons1 that situation. They had only turbine driven auxiliary 2 feedwater. pumps. They did have MSIV's, but of course they 3 essentially had steam generators.
4 MR. EBERSOLE:
5 MR. ROSSI: I think we are done with Rancho Seco.
6 MR. HERNAN: Jesse, after the meeting two months 7 ago you supplied some written questions to the staff on 8 dealing with main steam isolation valves or-in this case 9 the lack thereof.
10 MR. EBERSOLE: Yes.
11 MR. HERNAN: And the other dealing with whether 12 the operator should have tripped the reactor coolant
() _13 pumps. We have provided written responses to those, and I 14 don' t if you got yours this morning and have had a chance 15 to read it over yet.
16 MR. EBERSOLE: I just got it this morning and 17 haven't looked at it.
18 MR. HERNAN: Okay. If there are some questions, I 19 guess we would be prepared to further discuss those.
20 MR. EBERSOLE: Before our meeting with the full 21 committee I will-have gone through these. Thank you.
22 Okay, Ernie.
23 MR. ROSSI: Next we have an event on Crystal River
'24 Unit 3. That event will be discussed by Harley Silver from 25 the Office of Nuclear Reactor Regulation.
(n)
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15463.01L01I 48 llhnsry'simons11 MR. SILVER: Good morning. I am Harley Silver',
.2 the NRR. Project Manager on Crystal River 3.
. ~3 (Slide.)-
4 . Crystal River is a B&W plant. It does have the
.5 EFIC' system installed just to answer some of the questions 6 .that will probably arise.
7: It does have the capability to feed and bleed
.8 .through the safety valve and it does have MSIV.
9 . MR. EBERSOLE: You said the safety valve. That.is 10 the spring. loaded safety valve?
Ill MR. SILVER: Yes, sir, or the PORV's.
l12 MR. EBERSOLE: The PORV's are always questionable
( ). . 11 3 .in view of.the fact that they have' unqualified electric 14 apparatus. But if they can go through the safety valve, 15 that-is a clear shot?
~16 MR. SILVER: That is correct.
17- MR. EBERSOLE: Okay. Thank you.
- 18 MR. SILVER: The event ~that I am going to discuss 19 happened on November 22nd. It involved a partial failure
- 20. of main feed flow, an aux. feed actuation and a reactor
' 2'l- ' ' trip.
22 The significance of it is questions have been 23' raised regarding procedures and training of operators, post-
.24 trip review, operability of some aux feed ' components and of
( f; '25 course unnecessary aux feed challenges.
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5463 01 49 kncrysimons1 The circumstances of the event are these:
2 The plant was coming down to repair a dropped 3 control rod at about 20 percent power. The operator made 4 some choices in handling the main feed system which 5 contributed to the problem.
6 In manipulating the main feed system, the feed 7 control is on pump speed control down to about 45 or 50 8 percent power. Below that the main feed line it locked 9 closed and there are two bypasses around this block valve.
10 One is a 10-inch valve, a control valve with block valve 11 that is called a low-load control valve, and the other is a 12 6-inch bypass called a startup feed control valve which
( -) 13 also has a separate block valve.
14 These two valves are used to bring the plant down 15 to somewhere in the range of 15 to 20 percent power at 16 which time the 10-inch bypass valve is secured and the 17 plant is brought down to full shutdown using the 6-inch.
18 valve.
19 At about 20 percent the operator switched to the 6-20 inch valve as normal, and then apparently recalled that 21 this particular 6-inch valve, and incidentally this is all 22 'on one steam generator and the other continued to function 23 in the normal way.
24 The operator recalled that this particular 6-inch Q
t s,j 25 valve had exhibited on a previous shutdown, had exhibited ACE FEDERAL REPORTERS,'INC.
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l l
I 1
l 1
5463 01 Ol' 50 l
llhaarysimons~1 erratic control characteristics. So he decided to bring ;
2 down this steam generator on the 10-inch control valve. ;
3- In switching back to the control by the 10-inch 4 valve he simply shut the 6-inch block valve. The 10-inch 5 valve being a smart valve was almost closed because we are 6 20 percent power.
7 When he shut the 6-inch block valve, the 10-in 8 block valve, which is a slow acting valve to start with, 9 exhibited sluggish operation on top of that and could not 10 open fast enough to make ---
11 MR. WARD: You said the 10-inch block valve?
12 MR. SILVER: I am sorry, the 10-inch control valve t)
v.
13 of course. It could not maintain level in the "A" steam
=14 generator and level in fact did drop until the EFIC 15 act'uation trip point for aux feed. Aux feed did in fact 16 initiate and the operators quickly secured aux feed, that 17 is shut it off.
18 The reasons for this are related to their past 19 history of aux feed operation. The EFIC system was' 20 installed at this last refueling shutdown which ended in 21 August and the operators of course have been trained in 22 EFIC, but I gather had not fully come to accept the 23 performance of the EFIC system in aux feed.
24 MR. EBERSOLE: May I ask a question?
() 25' MR. SILVER: Sure.
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5463 01 01 51
_ lhmErysimons1 MR. EBERSOLE: How many steam generators are 2 there?.
3 MR. SILVER: Two.
4 MR. EBERSOLE: There are two?
5 MR. SILVER: Yes.
6 MR. EBERSOLE: You are at 10 percent power.
7 MR. SILVER: Twenty percent.
8 MR. EBERSOLE: The other steam generator is fully 9 competent to take care of heat rejection or the power 10 level, isn't it?
11 MR. SILVER: Yes, I would think so.
12 MR. EBERSOLE: But what you are doing now is
) 13 taking the one steam generator which is having trouble with 14 level and doing a number of things to it, including trip 15 the reactor until you can align it. Is this a logical plan 16 of action?
17 MR. SILVER: Well, the reactor was not tripped 18 manually.
19 MR. EBERSOLE: I know, but I am saying the other 20 steam generator is competent to take on the load and the 21 main feedwater flow will deliver flow to it, will it not, 22 at this power level?
23 MR. SILVER: Yes.
24 MR. EBERSOLE: And at least in the interval of
() 25 time one steam generator is perfectly adequate, isn't it?
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5463 01 01 52 hmerysimons1 MR. SILVER: At 20 percent power if there were no 2 -feed flow, no main feed flow through one steam generator, I.
3 guess it depends on the characteristics of the 6 and 10-4 inch valve on the "B" steam generator as to whether or not 5 they could indeed supply adequate feed flow.
6 MR. EBERSOLE: I am just impressed by the fact 7 that you are treating this one steam generator as though it 8 were all steam generators.
9 MR. SILVER: I don't understand what you are 10 saying.
11 MR. EBERSOLE: I am saying you are treating it as 12 though it is taking the full burden of-heat rejection or
() 13 coupling to the turbine when in fact there is another one 14 that is carrying the steam load.
15 MR. SILVER: The_ fact that, as I will explain in a 16 moment, the reactor did start to heat up and trip on high 17 -pressure as a result of the shortage of feed flow through 18 the one steam generator ---
-19 MR. EBERSOLE: So it is not ompetent to run on
'20 one steam generator at 20 percent.
21 MR. SILVER: If sufficient flow couldn't be had 22 quickly enough to it, I would imagine it would be.
23 MR. EBERSOLE: So maybe there is a lag to the 24 other operative steam generator?
(~h
- (,) 25 MR. SILVER: .The other 10-inch low-load control I
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5463 01 01 53 lllmnrysimons1 valve, as I said, is a slow acting valve, and it may be 2 that the inability of that valve to respond as quickly as 3 the steam generator tends to ---
{
4 MR. EBERSOLE: So in the operating mode I am 5 learning that you need full level on both steam generators.
6 MR. ROSSI: Well, I don't believe these plants are 7 designed to run in power with only one steam generator. I 8 think that is the situation.
9 MR. REED: At 20 percent power?
t 2
10 MR. ROSSI: They aren't designed to do that 11 normally.
L 12 Is that correct?
13 l MR. SILVER: That is correct as far as I know.
l 14 ! MR. ROSSI: They may be capable of doing it had 15 l they been designed in such a way to allow them to do it but 16 I don' t believe they were designed that way.
17 MR. MICHELSON: I assume these are air operated 18 valves; is that right?
19 MR. SILVER: No, sir. I believe ---
20 MR. MICHELSON: How can a valve be sluggish if it 21 isn't air operated?
22 MR. SILVER: If was a function of control settings 23 and stem lubrication apparently.
24 MR. HERNAN: Harley, at the time the reactor
~
N 25 tripped, wasn't the unaffected steam generator on the ACE FEDERAL REPORTERS, INC.
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5463 01 01 54 kmsrysimons1 startup valve, the 6-inch valve?
2 MR. SILVER: I have to assume they were running 3 parallel, yes.
4 MR. HERNAN: I thought you said they had shifted 5 over to the 6-inch valve.
6 MR. SILVER: I don't know this for an absolute 7 fact. I assume that they did both steam generators are 8 essentially the same time.
9 MR. EBERSOLE: So it was limited then in this 10 function?
11 MR. SILVER: Yes.
12 MR. MICHELSON: But a 6-inch line is all you need 13 for 20 percent power, but you had already scrammed as 14 well. So you are talking about two percent.
15 MR. EBERSOLE: No, he was up running at 20 16 percent.
17 MR. SILVER: And we are still running at this 18 moment.
19 MR. MICHELSON: You are sure these are motor 20 operated valves?
21 MR. SILVER: Yes, sir.
22 MR. EBERSOLE: Okay.
23 MR. SILVER: The operators in any event apparently 24 because of fear of excessive cooldown secured the aux feed 25 to the "A" steam generator. Along the way they did have ACE FEDERAL REPORTERS, INC.
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-5463.01 01 55 Jllmnrysimons1 difficulty in closing the aux feed steam emission valve to 2_ the stream driven pump apparently because of a lack of 3 understanding on the part of one operator the need to reset 4 aux feed in order to permit closing of that valve.
5 This was called to his attention and they did 6 reset -- I said aux feed and I meant EPIC -- they did reset 7 EPIC and indeed close the valve.
8 With aux feed closed now and the sluggish 9 operation of the 10-inch bypass valve they was stiff 10 insufficient flow to maintain adequate level in the "A" 11 steam generator.
12 MR. EBERSOLE: Why did he close aux feed when he
() 13 had insufficient flow?
14 MR. SILVER: My understanding of that is that the 15 operators did check with each other on the fact that there 16 was main feed flow in the "B" steam generator and that they 17 expected the 10-inch valve to adequately take care of flow 18 in the "A" steam generator.
19 MR. EBERSOLE: And it didn't respond.
20 MR. SILVER: It did not respond, that is correct.
21 There was adequate level to avoid another aux feed 22 initiation, but not an adequate level to prevent primary
-23 heatup and the reactor did indeed trip on high pressure.
24 (Slide.)
25 As an auxiliary detail, if you will, the operators
[~/)
x_
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5463 01 01 56 hmsrysimons1 observed the high-p':: essure trip coming and attempted to 2 open the PORV to avoid the trip. They commanded it to open 3 and it did not. At least there was no indication on the 4 tailpipe temperat.ure or the acoustic sensor on the 5 tailpipe, there was no indication of actual flow through 6 the PORV.
7 MR. FBERSOLE: When you say, however, it was 8 blocked closed ---
9 MR. SILVER: Well, no. It was then blocked 10 closed. Th'.s slide may be a little misleading. The block 11 valve had been open in the normal position.
12 ER. EBERSOLE: Okay.
1s j 13 MR. SILVER: When the valve did not respond and 14 did not open, they commanded the PORV to close even though 15 it actually had not opened and then closed the block valve.
16 MR. EBERSOLE: Well, then, let's see. They closed 17 the b7 ock valve and then you say later it was found to be 18 failed open.
19 MR. SILVER: That is correct.
- 20 MR. EBERSOLE: What are we talking about, the 21 bic-ck valve?
22 MR. SILVER: No. After the event when things were 23 stable and the reactor was rhut down, they opened the block
, 24 valve and found the PORV to be open at that point.
() 25 MR. EBERSOLE: Did it still have a persistent open ACE-FEDERAL REPORTERS, INC.
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~5463 01 01 57 lhmnrysimons1 signal?-
2 MR. SILVER: I don't know what the signal was, but 3 they could not then close it.
. 4 MR. EBERSOLE: It suggests, you know, when you j 5 close the block valve that you eliminated the DP and it 6 went on and opened when it couldn't have opened against the 1 7 real DP.
8 MR. SILVER: That is correct, except that it.did 9 have a close command. The last command given was to close.
10 . MR. EBERSOLE: Well, okay.
11' MR. ROSSI: Why don't you mention if you can what
- 12 the ultimate cause of the PORV to open was and that may p I / 13 clear up the situation.
14 MR. SILVER: There had been previously a relay 15 replacement in the PORV to gain a couple of contacts for 16 some signal purpose, and I am afraid I don't know the s 17 specific purpose. In examining the valve after this 18 occurrence, there were-found to be a couple of contacts-19 burned on this relay. Again, no one knows exactly when it 20 happened or how it happened or how that causes strain or~
21 seqilence of events in the PORV.
22 MR. EBERSOLE: There was only one PORV?
23 MR. SILVER: Yes, sir.
24 MR. REED: What kind of a PORV was this? Was this L( 25 an internal pilot operated PORV?
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.1 5463.01-01 58 lhnurysimons~1 MR. SILVER: Yes.
- 2- MR. REED
- How many times are they going to have 3 .these fail and not listen to the comments that have been 4 made about the hydrogen impact and the boron impact on the 5 internal pilot operated PORV's? Quite frankly I think 6 there is a reliability aspect here that relates to this 7 kind of PORV.
8 MR. EBERSOLE: You mean on bleed and feed as well?
9 MR. ROSSI: Harley, this particular failure was 10 not associated with the valve as I understand it. This was 11 a relay.
12 MR. SILVER: I have not heard that they have
_ , ~ .
(_) 13 dismantled the valve or examined the internals of the valve 14 at all.
15 MR. ROSSI: You'may have a reliability problem 16 with the valve, but it is my understanding, and correct me 17 if I am wrong, that.this particular failure was a relay.
18 MR. SILVER: That appears to be the case, yes.
19 MR. REED: You say it is a relay, but I am not so 20 sure. I have challenged the operability and reliability of 21 internal pilot operated leak valves on borated and 22 hydrogenated PWR systems, and I think that challenge is 23 worthy of investigation.
24 MR. ROSSI: I understand,
('-)
f 25 MR. EBERSOLE: Ernie, are these DC valves actuated ACE-FEDERAL REPORTERS, INC.
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5463 01 Ol'- 59 kusrysimons1 to open, these PORV's?
2 MR. ROSSI: I don't know.
3 MR. EBERSOLE: Glen, do you know? In general-4 aren' t they DC operated VSlves?
MR. REED:
5 On PORV's?
^
6 MR. EBERSOLE: Yes.
7 MR. REED: Well, most of them in the early days 8 were air operated valves.-
9 MR. EBERSOLE: I am talking about the solenoid 10 that opens the air supply, d
11 MR. REED: Yes.
12 MR. ROSSI: 'It is probably off of vital supplies
'3
((,/ 13 that ultimately go back to the DC at some point.
, 14 MR. REED: After Three Mile Island the air i
15 operated ones were upgraded to have accumulators.
16 MR. EBERSOLE: Well, you know if it is an AC
.J.
17 solenoid and the core doesn't move, then you will get L
l 18- burned relays as an automatic consequence. Was that looked
, 19 at?
20 MR. ROSSI: I don't know.
!~
21- MR. EBERSOLE: The sustaining current can't be d
L22 carried by the relays, can it?
'23 MR. ROSSI: Do you know that af ter they fixed this 24 they must have retested the valve and so forth?
, - l( ) 25 MR. SILVER: The tested it 70 or 80 times I am ACE-FEDERAL REPORTERS, INC.
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5463 01 01 o 60 llhmerysimons1 told.
2 MR. ROSSI: The circuit, the valve and everything?
3 f1R. SILVER: That is correct. They actually 4 operated the valves.
S' MR. EBERSOLE: You know, Ernie, if the AC and AC-15 meter doesn't move it will kill the relay.
7 - MR. ROSSI: I understand, yes.
8 MR. REED: I now appreciate what you said, and it 9 is going to be very_ difficult to ---
10 MR. ROSSI: The cause of the relay context could 11 have been a root cause.
12 MR. REED: The failure of the valve not to move k,s) 13 because of hydrogen effects or boron scum effects in the 14 pilot.
15 MR. EBERSOLE: Okay.
16 MR. WYLIE: I am a little confused. You say the 17 valve, the PORV failed to open and it was blocked by the 18 block valve; is that correct? .You said it blocked closed.
19 MR. EBERSOLE: They then blocked it.
2 20 MR. SILVER: It failed to open and then they 21 blocked it.
22 MR. WYLIE: Oh, okay.
23 MR. SILVER: My apologies for the wording'on the 24 slide.
O i ,) 25 MR. REED: The issue here is again the complicated ACE-FEDERAL REPORTERS, INC.
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5463 01 01 61 kmcrysimons1 and integrated control system which is really for the 2 purpose of main steam production. It has got all kinds of 3 complexities and the operator is trying to work with it.
4 He is shutting off valves and opening valves. And yet this 5 system is integrated into the decay heat removal system.
6 Now you tell me the unit can also bleed and feed, 7 but you also j ust told me that the PORV didn't open.
8 MR. ROSSI: Harley, can the plant bleed and feed 9 through the safeties?
10 MR. SILVER: Yes, indeed it can.
11 MR. REED: You say this particular plant and thi7 12 particular unit, but it still overrides the safeties.
() 13 MR. ROSSI: I believe that is what you are saying, 14 rig ht , Harley, without the PORV?
15 MR. SILVER: Yes.
16 MR. REED: What is the figure? I think you said 17 2250.
18 MR. SILVER: I don't know the exact figure, but 19 2300 or 2400.
20 MR. ROSSI: It is more likely 20 to 24 or 25.
21 MR. REED: And this can deliver what, seven or 22 eight hundred gallons a minute?
23 MR. ROSSI: You are sure, Harley, that the plant 24 can bleed and feed through the code safeties?
I) 25 MR. SILVER: Absolutely. I don't know the flow ACE-FEDERAL REPORTERS, INC.
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{
llhmcrysimons1 rate.
2 MR. REED: In other words, you can get seven or 3 eight hundred gallons a minute through the safeties with 4 the pump installed?
5 MR. SILVER: I am not sure of the flow rate, but 6 you can indeed get flow through the safeties.
7 MR. MICHELSON: Yes, but when you say that you can 8 feed and bleed, I am trouble with adequately feed and 9 bleed.
10 MR. SILVER: Yes.
11 MR. MICHELSON: And therefore you have an adequate 12 flow at 2400 pounds ---
13 MR. ROSSI: Well, you can recheck that if you want 14 to, but you are quite sure that this particular plant can 15 bleed and feed without the PORV and just the self-actuated 16 safeties?
17 MR. SILVER: Yes, sir.
18 MR. MICHELSON: Was there an augmented 19 investigation of this particular event?
20 MR. SILVER: No.
21 MR. MICHELSON: Why wasn't there?
22 MR. SILVER: This one would have been looked at by 23 team.
24 MR. MICHELSON: Well, yes, that is what an 25 augmented team does.
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5463 01 01 63 marysimons 1 MR. PANCIERA: The region had emergency inspectors 2 present during the event and after the event. They did the 3 investigation. The region was very heavily involved in 4 trying to ferret out the facts.
5 MR. MICHELSON: May I used the wrong term. Isn't 6 your augmented inspection coming from the region? i 7 MR. ROSSI: Well, let me go back through that 8 again. Every event gets looked at by the region, every 9 one. So there is always some inspection and for the bigger 10 events there is more regional involvement. That is not the 11 augmented.
12 The augmented one is a level higher where in 13 addition to the regional inspection there will be experts 14 sent from headquarters in technical areas to do a higher
! I 15 l level investigation of an event.
t 16 MR. MICHELSON: There are three levels then.
17 MR. ROSSI: There are really three levels when you 18 include the one that is normally done by the region in 19 their normal regional work of following every event through 20 the resident and through the regional based ---
21 MR. MICHELSON: So you felt this did not warrant 22 an augmented team.
23 MR. ROSSI: This one was left to the region.
24 MR. MICHELSON: Now when the region alone goes to 25 check, what kind of report would I be able to find?
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5463 01 01 64 lhmrysimonsl' MR. PANCIERA: The resident inspector, for every.
2 significant event'he will document that inspection through 3 his periodic inspection reports, and this item is being 4- documented through his periodic inspection reports.
5 MR. MICHELSON. Could you send to me or to the 6 ' office a copy of whatever was documented for this event?
7 MR. PANCIERA: I would be glad to, yes, sir.
8 MR. MICHELSON: That is the first level. Now the 9- second level is if you had asked for help from 10 headquarters?
11 MR. PANCIERA: Well, let me clarify one thing.
12 There is also another level. In other words, on p
. i ,) _ 13 significant events the resident inspectors will investigate i
14 these events. If the resident inspector feels that he is-15 not in a good position of doesn't have the knowledge or i 16 needs assistance, he will call on the region. The region 17 -then will send a team down, and we call that a reactive 18 inspection.
19 In fact, we just completed a reactive inspection 20 on another plant just last week.
21 MR. MICHELSON: This event d d not receive a 22 reactive inspection?
23 MR. PANCIERA: It did not receive a reactive 24 inspection.
. ,Q
(_) 25- MR. MICHELSON: It was j ust the local resident ACE-FEDERAL REPORTERS, INC.
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5463.01 01 65 trysimons 1 : inspector.
2 MR. PANCIERA: Just ,the local resident inspector.
3 M R. MICHELSON: Are you satisfied that that is all
- g. e' 4 this event'needed? o
.5 MR. PANCIERA: Let me juat say one thing. The i-6 region was heavily involved with working yith the resident - -
, \ .-
7 inspector on a daily basis. ,In. f, ac t , in so'me cases' eve'n"- -
8, more than on a daily basis. , .{p i
9 MR. MICHELSON: Well, I would like.to see whatever 10' report was written on thes event and that I am sure will --
}"
11 clear it all up when'I read your procedure that you are
- 12. implementing. -
[ )
We are nov prepared to give you a copy *
./~)-
1 13 MR.-ROSSI:
14 of the augmented inspect. ion procedure. Wq have copies here 15 and we will pass them out.
16 MR. MICHELSON: Oh, you mean they are not 17 available yet?
18 MR. ROSSI: Well, I don't know whether you have 19 it.- We just happen to have a copy. Somebody here had it 20 and they will Xerox copies since there have been so many 21 questions asked and you might as well look-at it. I medh~
22 not right now but later on we will have it.
23 MR. REED: On this Crystal River event where your
. 24 ' defense that you stated to me for decay heat removal is the
.<8 25 pumps could deliver the quantity;of fluid required while
( ,/ ,
's ,
i M- -
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"-5 4'6 3 . O l' 0 1-66 kabrysimons1 ' pushing through the safeties; I would liPe to point out at 2 .that there are many things that come to bear on the real
'3. safety of the decay heat removal, and one of these is the fy 4 argument on pressurized . thermal shock.
t 4
. 5 What you are telling me here is that your defense 6 against my attack against the auxiliary feed system 1 s 7 vulnerabilities is that.you are going to push the pressure l 8 up to'2350 or.2400 and put seven or eight hundred gallons a 9 ' minute of water through it and you are not concerned.about
~
10' another aspect of pressurized thermal shock.
11 On the'other hand,-if the PORV works and you pull 12 the pressure down,_I can understand you wouldn't do it in a TT
' (,/ 13 sense and just push the pressure up.
14 MR. ROSSI: Well, typically there is a 200 psi
~
15 difference between the safety valves and the PORV,- but 7
16 please ---
17 . MR. REED: No, wait a minute. Wait a minute.
18 PORV --- . .
19 .MR. ROSSI: Well, PORV you can open. You can open
\-
20 and bring it all down all the way. That is true. But 21 don' t misunderstand what we are saying. The auxiliary f
-22 feedwater system is the primary system to be used when you
+
23 don't have main feed, and we are looking at that system i
l 24 also. I mean that system is receiving a lot of attention
\
l-()- 25 and these other things are there is you have a total l
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'r 67 kanrysimonsl' . sustained failure of that system.
1 2 . MR. REED:- And it is so complicated'in its -
K/ ' ,
f3 ~ operation ~and the operator burdens that in order to i
4 , accompl.ish the issue of power production and large decay-5 ' heatr removal-that I amLeoncerned, and'you have incident g
'* L . -- -
6 atter incident. piling-up here on these concepts.
q;jn
/J'l 7 _ MR. HERNAN: Glen, you mentioned vulnerability to
-8 'the aux-feedwater system. In this case the aux feedwater:
-9 syste,m didn't come-on. It wasn't needed or wanted by the
!T
- la ope r'a tor .
.11 MR. REED: . Are you aware that unless the water is
= 12 - stored at the right location that that can be a problem,
) -13 depending.on whether or not you have lost outside ---
1 11 4 MR. HERNAN: I am'not-sure how this relates to 15 this event.though.
+- .
16 MR. REED:
~
I-don't look at' events. You told me at--
117 the outset to take your events:and. carry them forward to
^
9.l .
18 issues,'to generic issues and unresolved issues, and that 3
19 iis what I am doing.
1:
20 - MR. ROSSI: We understand.
- p /{
21 :MR. PANCIERA: I would like-to point out though 22 that other than the operator action in this case, there was nti Sqff( 23 no failure whatever of the aux feed system. And in fact it kd, ' 24- is firmly believed that the aux feed and EFIC system would
?[(, -
~
- 25 have controlled this event entirely automatically and jhl ' . n es
p s.
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5463 01 01 68 C l hm::rysimons 1 entirely by itself had the operators kept hands off.
2 In fact, there have been several subsequent 3 initiations of aux feed, spurious actuations which after 4 training the operators if simply left alone and they found 5 that indeed the system does control perfectly.
6 MR. REED: I have to ask you, is your background 7 as a designer?
8 MR. PANCIERA: If you go back far enough.
9 MR. REED: You have been a designer? .
10 MR. PANCIERA: I have done that sort of thing, 11 yes.
12 MR. REED: My background is more as an operator, 13 and I am very cognizant of the operator burdens and 14 procedures and the fact that vulnerabilities may exist and 15 they should be criticized.
16 MR. ROSSI: Well, your main concern is the 17 complexity of some of these particular safety systems from 18 the operator's standpoint. That is your big concern, or 19 one of your big concerns.
20 MR. EBERSOLE: Ernie, I had never heard a 21 reference to bleed and feed being a possible contributor to 22 high-pressure thermal shock. That is, it never occurred to 23 me that if you were too successful at bleed feeding at 2400 24 pounds against the safeties you would have an abnormal load 25 on the primary vessel and perhaps a potential for undue ACE-FEDERAL REPORTERS, INC.
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.5463 01LO1 '69 acrysimons 1 chilling at least in certain places of the vessel,.you .,
2 know, at an excessive high-pressure load.- Is that a part-3 of the PTS picture?
4 MR. ROSSI: I' don' t know the extent to - which that 5 aspect has been looked at in pressurized thenmal shock.
6 MR. EBERSOLE: You know feeding against safetv 7 valve pressures. I am talking about feeding against safety 8 valve pressures with cold water.
9 MR. ROSSI: I think that part of it has been
.10 looked at.
11 MR. EBERSOLE: Has it been?'.I don't remember.
12 MR. ROSSI: I mean I think it is a well-known g_
j ,1 13 situation.that if you have a over-cooling transient that 14 empties the pressurizer and turns some of~these systems.
.15 that then you depressurize.
16 PHl. EBERSOLE: But not against-safety' situations.
17 MR. ROSSI: Well, if you let them run long enough, 18 -that is where you end up.
19' MR. EBERSOLE: Okay. I guess it must be an L
20 integral part of it. All right. Let's go on.
21 MR. SILVER: Some minutes after the trip the aux
- 22. feed steam emission valve opened apparently spuriously 23 causing a mild over-cooling event well within tolerance.
24 MR. EBERSOLE: Let me ask a question on that. The
() 25 turbine, the aux feed pump turbine has got a stop valve to i
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5463D01-Ol' 70 harysimons :1 stop it if'it breaks I guess and runs away.
2' ' MR. SILVER:' Yes.
3 MR. EBERSOLE: It must have a governor. valve-to 4- _ modulate its rpm, and'then it has got an admission. valve.
'5 Which'of these valves are youLtalking about?
6 MR.' SILVER: The admission valve.
7L _MR. EBERSOLE: The one.in front of: the governor 8 valve?
19 MR. SILVER: I'believe so, yes.
10 MR. EBERSOLE: It is a two-position valve, open or
< 'll' shut.
- 12 MR. SILVER: Yes.
~
- 13 ' MR.~ EBERSOLE: But when it opens, unless'there is
- 14 a signal ~ to have the governor valve open with the stop
~
15 valve'open, why does the turbine move at all?
16 MR. SILVER: I am sorry, when it opens why ---
- 17. MR. EBERSOLE: _ When it_ opens it-applies steam 18- pressure to the-governor valve which controls the speed of
- 19. the turbine, does it not, and then that modulates the 20 turbine speed. . So what made -it start just because you -
21- ' opened the emission valve?
22- MR. MICHELSON: Jesse, I don't think it is quite 23' that complicated. I suspect it only has a control valve or 24 an emission valve._ It doesn't have a fast stop. .I think
() .25 the fast:stop is part of the control on this one. .They ACE-FEDERAL REPORTERS, INC.
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?S463 01"01- 71 L marysimons'1 . don't.have a separate stop_ valve and a separate control ---
2 .MR.-EBERSOLE:. I didn't think the opening.of an 3 admission valve, which I.didn't put a control function 4 into, actually started the pump.
5 MR. ROSSI: I believe it does.
6 MR. MICHELSON: Yes, it does on these Terry 7 ' turbines.
8 MR. EBERSOLE: And then does it subsequently
,9 govern?
10 MR. MICHELSON: No. The control valve would do 11 .that.
12 MR. EBERSOLEt So the governor valve is open?-
7'N J) t 13 ,
MR. MICHELSON: The control valve is open.
14 MR..ROSSI: I thought what generally happened is 15 you start the pump up and it comes up to some full speed
'6 1 and then they can control it perhaps from the control room 17- later on. I think that is the way it is with the set-up.
18 MR. EBERSOLE: It is set up generally to be a wide 19 open start?
- :2 10 MR. ROSSI: Yes, and to give you auxiliary feed to 21- ensure the capability of removing decay heat, and then it 22 is.left to the operator to throttle back in a lot of cases.
23 MR. EBERSOLE: So it is like the diesels and the 24_ generic problem. We tend to start our machinery flat out,
() 25 wide open, and then ask the-speed controls to intercept and ACE-FEDERAL REPORTERS, INC.
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~5463 01'01' 72 hmirysimons1 'overspeed transient;-is that correct? Almost universally 2 we do that?
3 MR. ROSSI: Well, generally when you actuate these 4- systems they go to the state that is required to perform 5 their safety function.
- 6. MR. EBERSOLE: Well, they go to the overspeed 7- state,, don't they, and then we ask the governor. controls to 8 intercept the overspeed?
9 MR. ROSSI: The governor is supposed to prevent an
,10 overspeed.
11 MR. EBERSOLE: Would it not be prudent to look at 12 the thesis that you should not start machinery'like this
-O
\ ,/; 13 including the diesels flat out full throttle, but rather 14 modulate the opening and not ask the overspeed device to t 15 have to do its thing? i 16 MR. ROSSI: I don't have an answer to your 17 question.
18 MR. EBERSOLE: Do you follow what I am saying?
I' 19 M R. ROSSI: I would point out that as part of the 20- . Davis-Besse view after the event, the reliability of the 21 governor and so forth is being looked at.
22 MR. EBERSOLE: Well, does that include looking at 23 a modulated start rather than a full open throttle start?
24 MR. ROSSI: I don't think it does, no.
() 25 MR. EBERSOLE: If not, why not?
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m 4 .5463:02 02 73 u (R_)marysimons 1 MR. HERNAN: . Jesse, I don' t think you' can really 2 make a ' direct comparison between the diesels and the aux 3 feed pumps. As the aux feed pump is . coming up it is i4 loading as l't. increases speed, whereas the diesel is not-5 available until it achieves full speed.
6 'MR. EBERSOLE: Tha t is true. So it has an applied 7 load as it comes up, unless the regulating valve is shut, 8 in which case the re is no load. So I am not so sure that 9 your statement ---
10 MR. HERNAN: There is still load.
1 11 MR.-EBERSOLE: .There is a moderate load. The re is 12 a' stirring load.- Well, let's go ahead.
) 13 MR. SILVER: There was a spurious opening of that 14 steam esission valve , but the licensee has not been able to 15 duplicate that. So that there is no known reason for'that 16 a t the mome n t . They have attempted to produce this result 17 and have not succeeded.
18 The follow-up actions involved, I broke them up 19 into 'several categories. Of f-speed reliability involving 20 excessive challenges to off-speed, I think it has already 21 been mentioned that the B&W owners group has an effort 22 . going to improve main feed reliability and thereby reduce.
23 challenges to aux feed.
J 24 The. Question of EPIC transmitter transmitter p
(_) . 25 sensitivity, I guess I did not mention that. On the l 1
l l
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(_/msrysimons 1 following day during a calibration of the EPIC system a
\
2 _ spurious actuation of EFIC did occur. There .have been
'3 otherl spurious actestions of -- I shouldn't say spurious.
4 There have been other actuations of the EFIC aux feed 5 system due~ to -- apparently due to pressure spikesiin the 6 secondary system.
7 The sensitivity of the Rosemont level transmitters 8 is severe apparently and any pressure purtubation in the 9 secondary system will cause aux feed' actuation. A design 10 change is in the works between B&W and the licensee. At 11 the' moment we do not have a firm schedule on when this will
'12 be. accomplished.
+
. (G/. -13 MR. EBERSOLE: In the prior discussion on Rancho
- 14 Seco, does it have an EFIC system?
15 MR. SILVER:, One is going to be installed, and I 16 think Sid mentioned that, at either the next refueling or 17 a t 'some time in the f u ture . Arkansas does h' ave one. That
! 18 is the only other plant, I think.
'19 MR. EBERSOLE: Any other questions for Mr. Silver?
20 (No response . )
f 21 Ernie, I gather you presented these two first ones 22 as kind of a package of B&W.
, 23 MR. ROSSI: I think Harley has a few more -things 24 to say_on this one.
25 MR. SILVER: I have a couple of additional ACE-FEDERAL REPORTERS, INC.
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(~Jmarysimons
\_ 1 comments on what we have seen.
~
2 (Slide.)
3 The questions on operator training and procedures 4 having to do with manipulation of the main feed valves, of 5 securing EFIC, that is.the advisability of not securing it 6 quickly even though it may not be needed, the- me thod of 7 securing, and that is in this case they simply trip-the
'8 electric pump and attempted to shut the steam pump 9 immediately. The preferred method would be to take it down 10 on the control valve.
11 The Question of understanding of the EFIC aux feed 12 system, the licensee has indeed changed the procedures to k_). 13 cover these items and has provided additional training to 14 the operators.
15 The question of post-trip review was raised by 16 this event and in effect the previous event during which 17 the f ailure of the 6-inch start-up control valve to operate 18 correctly, that was not repaired apparently prior to the-19 start-up in that previous shut-down, and there was not in 20 fact a disciplinary review.
21 The licensee has now instituted a procedure 22 whereby the plant review committee or at least a 23 subcommittee of the plant review committee will review all 24 start-up and approve the work that has been done prior to
./'N
(,J .- 25 the start-up.
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( mnrysimons 1 As far as equipment malfunctions, I think we 2 talked about the PORV, the steam emission valve, I 3 mentioned the sluggish operation of a feed valve, the low-4 load main feed valve which is a function of control set 5 points -- I have got a little error in the slide. The tube 6 and control pressure item, the last item, should be applied 7 to the low-load control valve operation, and the start-up 8 feed valve has been repaired.
9 MR. MICHELSON: Let me ask you a procedural 10 question. If NRR feels that you have not received adequate 11 information on that event, I guess you would just go back 12 to the region and tell them to get you more information?
) 13 MR. SILVER: We have done that and of course gone 14 to the licensee and asked them for some more information.
15 MR. MICHELSON: Now with this particular event, 16 are you satisfied now that you have all the information you 17 need to reach a judgment that further investigation isn' t 18 needed?
19 MR. SILVER: We have just yesterday, or I just 20 yesterday received the formal LER from the licensee. In 21 reading it quickly, I think we have sufficient information.
22 MR. ICH ELSON : Be twee n that and what you got from 23 the region?
24 MR. SILVER: Ye s .
() 25 MR. HERNAN: Harley, you might point out in this ACE-FEDERAL REPORTERS, INC.
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lv la rysimons 1 particular event we did have the utility come up to 2 Bethesda and have a meeting with top NRR management.
3 MR. MICHELSON: I see. Were minutes or something 4 produced?
5 MR. SILVER: Were it not for a two-week vacation 6 on the part of the project manager, minutes would be 7 available.
8 MR. MICHELSON: When I get a copy of the regional 9 information, can I get a copy of the LER -also? ,
10 MR. SILVER: Ye s .
11 MR. MICHELSON: Thank you.
12 MR. EBERSOLE: Why do we have such high confidence
() 13 you can bleed and feed with this plant, but not that same 14 one for Rancho Seco? Is there a particular difference in 15 .the designs?
16 MR. SILVER: Of feed and bleed?
17 MR. EBERSOLE: Ye s .
18 MR. STOLZ: Yes. The dead-head pressure of the 19 high-pre ssu re injection pump is the principal dif ference.
20 MR. EBERSOLE: Was that a deliberate addition to 21 this design not incorporated into Rancho Seco?
22 MR. MINER: I would say Rancho Seco is exactly the 23 same as Crystal River. I just don' t have the information.
24 The pumps are almost identical. I had Crystal River before l' 3
(_j 25 Harley did. So what he said, I would say that they are ACE-FEDERAL REPORTERS, INC.
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- n k Imnrysimons 1 exactly the same.
'2 MR. SILVER: I think the only plant that cannot do 3 this is Davis-Besse.
4 MR. STOLZ: That is right. Only Davis-Besse has 5 the problem. All the other plants have high-head pumps.
6 MR. ROSSI: John , while you hre up, can you 7 reverify that we are talking iout being able to bleed and 8 feed with the safety valves and not just the PORV?
9 MR. STOLZ: That is right.
10 MR. EBERSOLE: With the safety valves. So they 11 can forget the vulnerabilities of the PORV's. '
I 12 MR STOLZ: Ye s .
,m l
I) s- 13 MR. EBERSOLE: Okay. Thank you.
14 MR. REED: Why is there not internal pilot 15 operation of these valves?
16 MR. EBERSOLE: These are spring safeties.
17 MR. ROSSI: Now in all these cases of decay heat 18 removal with the auxiliary feedwater system and other 19 things, you do have to balance too much against not enough 20 and you can overcool and you can overpressurize. So there 21 is a balancing here, and I think these events have 22 addressed problems with that balancing, too.
23 MR. REED: I wonder in your new organization where 24 you have the B&W reactor concept in NRR group, is it?
25 MR. SILVER: Ye s .
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5463 02 02 79 marysimons 1 MR. REED: As you see these events unfold, and we 2 just listened to five events on B&W's, you can' t always 3 continue as you did in Three Mile Island to blame 4 operators. And there have been probably a half a dozen 5 other events in the last year where there is lots of 6 windmilling around with respect to auxiliary feed and the 7 heat sink path.
8 It seems to me in your new organization you ought 9 to begin to wonder if this design is a little bit difficult 10 to drop. In other words, you go back and you say is it a 11 Corvair and can you license operators to drive this unless 12 they are very special operators with high manual dexterity
/m k _) 13 and ---
14 (Laughter.)
15 MR. EBERSOLE: I knew you would get to that.
16 MR. REED: I think that you ought to have a 17 l special investigative team, not just for Crystal River and 18 not just for Rancho Seco , bu t for the concept.
19 MR. STOLZ: We agree with you.
20 MR. REED: Well, by gosh.
21 (Laughter.)
22 MR. STOLZ: We do have an owners group activity 23 poing on on feedwater. They have provided us a preliminary 24 schedule for their activities. They were primarily spawned
'O u/ 25 by the Davis-Besse event. We have questions that were ACE-FEDERAL REPORTERS, INC.
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'k.Jmcrysimons I spawned by the recent Rancho Seco event and they are coming 2 in tomorrow. We have fundamental questions on what is the 3 root cause of losino power to ICS and what are the 4 implications to the other B&W plants, and what happens when 5 that happens when you lose the integrated control system.
6 MR. REED: Let me make one last comment, and I 7 shouldn't be making this. Somebody else should. It is 8 interestinQ to notice we have Three Mile Island events, 9 Crystal River events, Davis-Besse events and Rancho Seco 10 e ve n ts . I never hear of Oconee events. Now is that 11 because Oconee has a feedwater system for decay heat 12 removal that is radically dif ferent, which I think it is?
MR. STOLZ:
13 Well, the Oconee feedwater system, as 14 you know, following the Three Mile Island, they added two 15 electric pumps. So they have that additional redundancy.
16 But they have the same fundamental control problems ---
17 MR. REED: For main steam production do they have 18 a dedicated auxiliary boiler feed system?
19 MR. STOLZ: I don't recall.
20 MR. WYLIE: They do.
21 MR. MICHELSON: As a matter of clarification for 22 Mr. Miner, does Rancho Seco alternately use motor operated 23 feedwater control pumps?
24 MR. MINER: I am not sure. I think they do, but I n/
x_ 25 am not sure. I would have to check.
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_ -( ,)carysimons 1 MR. EBERSOLE: Does Crystal River.have main steam 2 isola tion valves? I didn' t notice?
, 3 MR. SILVER: Yes,. sir.
4 MR. EBERSOLE: And why were they put in there and 4
5 not at Rancho Seco?
i --
6 MR. SILVER: I am afraid I can' t answer that. >
l 7 Be fore I leave, I have been asked to mention 8 .another incident which happened last week for which I do 9 not have a slide.
P 10 There was an apparent separation of the one 11 reactor coolant pump impellor from a shaf t and a resultant ,
12 trip on the flux flow mismatch at Crystal River. The plant
( )- 13 is now down and the pump is in the process of being removed 14 and there is no indication yet as to what the specific 15 cause was.
16 MR. EBERSOLE: I call the committee's attention to 17 the Palo Verde. They don' t have core problems because -they i 4
18 monitor flow, not by measuring flow, but by counting the 19 rivet heads going past on the flange.
20 MR.-REED: This is the second impeller event, J
21 correc t?
22 MR. ROSSI: There was one at Palisades sometime I i 23 think in the last year.
. 24 MR. REED: Is it the same make and model?
g 3
() 25 MR. ROSSI: My understanding is that they are both '
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'/~'N N-)Cerysimons 1 Byron Jackson pumps. I don' t believe they are the same 2 model.
3 MR. EBERSOLE: Do they have Byron Jackson at the 4 Palo Verde plants?
5 MR. ROSSI: I don' t know what Palo Verde has. I 6 am familiar with the measurement technique you just 7 mentioned.
8 MR. HERNAN: Jesse, I thought the Palo Verde pumps 9 were of foreign manufacture.
10 MR. EBERSOLE: I am not sure. Oh, I believe you 11 are right. That is why they had all f.he trouble with .them.
12 (Laughter.)
g
(_) 13 MR. SILVER: I really have no further information 14 on that particular event and probably von' t for several-15 days.
16 MR. EBERSOLE: Thank you.
-17 Any further questions on this topic?
18 (No response.) ,
19 Le t's have a break until 10:25, please.
-20 (Recess taken from 10:15 a.m. to 10:25 a.m.)
21 MR. EBERSOLE: Le t's reconvene the meeting, and 22 Ernie again, I will turn it back to you.
23 MR. ROSSI: The next discussion that we have is 24 some reactor trip breaker failure problems at the D. C.
25 Cook plant, and this will be given by Vince Thomas from the ACE FEDERAL REPORTERS, INC.
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'( )ccrysimons 1 office of Inspection and Enforcement.
2 MR. THOMAS: My name is Vit:ce Thomas, and I am 3 with the Of fice of Inspection and Enforcement.
4 (Slide.)
5 ! On October 29th one of the reactor trip breakers 6 at D. C. Cook, Unit 2 failed to automatically open upon the 7 receipt of a scram trip signal. Howeve r , the scram 8 function itself was accomplished because its redundant 9 breaker breaker had indeed opened.
10 Following the notification by the licensee, D.C.
11 Cook, to the NRC, staf f members from both NRR and I&E were 12 sent to the site for an augmented inspection to assist
) 13 Region 3 in their follow-up on the event.
14 Although at the time we were concerned about the 15 malfunction of the UVTA's from the earlier experience at 16 Salem in 1983, until the November 3rd incident, we were 17 unable to determine whether the 29th event was a hang-up -
18 failure or there were indications presented for a' normal 19 mode f ailure .
20 On November 3rd, 1985, four days af ter the event, 21 the recent event, while testing the remaining breaker on 22 Unit 2, they experienced motor failure with one of the 23 reactor trip breakers. In fact, it was a breaker that had 24 essentially worked properly in the October 29th event.
) 25 The requirements were a little bit different in ACE FEDERAL REPORTERS, INC.
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5463 02 02 f 84 (o_)ctrysimons 1 the formal testing of the breaker for October 29th. The re 2 was a requirement that they put a maximum force margin te s t 3 trip margin on the breaker itself. They put a 20-ounce 4 weight on the trip bar, de-energized the undervoltage trip 5 attachment and then the breaker was supposed to trip.
6 Whereas, on the 29th that was an actual signal coming f rom 7 the reactor protective system and no weight on the bar as 8 installed and it didn' t trip.
9 Woll, af ter the second event obviously this raised' 10 our concerns about the Westinghouse designed plants that 11 had not implemented as yet the automatic trip feature of 12 the shunt coil which is part of the DB-50 breaker.
/~T
- (,)
13 A little bit of background on that. I think 14 following the early 1983 failure that occurred at Salem, 15 the Westinghouse owners group committed to install a backup 16 to the -- and Ernie , you can correct me on this -- a backup 17 to undervoltage trip attachment, and the automatic signal 18 was to also ao to the shunt, trip coil.
19 Apparently D. C. Cook 2 didn' t do that as yet, f
20 MR. ROSSI: That was part of Generic Le tter 83-28, 21 that all plants wired for shunt trips have the automatic 22 trip system. It is my understanding that all the 23 Westinghouse plants that have the shunt trip, they all 24 rated manually.
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_/marysimons 1 trip on the breaker, to give you the manual feature of 2 scramming the breaker.
3 MR. EBERSOLE: Why is it that these persist in not 4 having a shunt trip breaker?
5 MR. ROSSI: They are committed to put it in, and 6 it is a matter of scheduling.
7 MR. EBERSOLE: What is it more than a couple of 8 auxiliary relays?
9 MR. ROSSI: Well, when you put some thing like this 10 in, it has to be safety related. So you have to worry i 11 about its interactions, separations, redundant trains, 12 capability and all of that.
(\
()_ 13 MR. EBERSOLE: What can it do bad?
14 MR. ROSSI: We ll , if it is put in improperly I 15 suppose you could have a failure to one division that 16 causes failure to the other one.
17 MR. THOMAS: The relay itself is there.
18 MR. ROSSI: I mean it always looks like a simple 19 change until you go to look at all the things involved with 20 the separation and the testing. The testing itself, you 21 know, has to be looked at pretty carefully if you want to 22 make sure you test the shunt independently of the 23 undervoltage trip a ttachment.
24 But in any event, all of these plants are
(~'\
(,) 25 committed to wire the shunt in to the automatic system, and ACE-FEDERAL REPORTERS, INC.
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,)marysimons1 even before that they did have it there as part of the 2 manual trip. I think you have a list of which plants don't 3 have it and which ones were operating at the time of this 4 occurrence.
5 MR. EBERSOLE: If I understood you correctly, one 6 breaker f ailed on an actual demand and the other breaker 7 failed on a test. So we were clocked for a concurrent 8 failure.
9 MR. ROSSI: Well, keep in mind that the second 10 failure, it failed a margin test. It didn't fail on 11 demand. That is a little bit dif ferent. It was lacking in 12 the proper design margin.
O) 13 MR. THOMAS: As a result of the second failure ,
14 the staf f then raised the concern, as I said before , about 15 the Westinghouse plants, and it was on this basis that we 16 issued the IE Bulletin 85-02 that went out on 11/5/1985, 17 and the second event occurred on November 3rd, 1985.
18 The bulletin only addresses those p] 9nts that were 19 in operation, actually operating that had not yet 20 implemented the automatic features of the shunt trip coil.
21 MR. EBERSOLE: How long do they have to do that?
22 How far off? How many more years?
23 MR. THOMA S: Well, until they ge t the automatic 24 shunt trips in.
() 25 HR. EBERSOLE: That is what I mean. How many more ACE FEDERAL REPORTERS, INC.
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(.)morysimons 1 years?
2 MR. THOMAS: All right. The Beaver Valley, Turkey 3 Point and Kewaunee, I think the outside is May of this 4 year. .One has already got it in I believe, Beaver Valley, 5 and Kewaunee is due next month.
-6 MR. EBERSOLE: What is going to happen to D.C.
7 Cook?
MR. THOMAS:
8 D.C. Cook has already implemented it.
9 MR. EBERSOLE: They are putting in the shunt 10 trips.
11 MR. THOMAS: They have got it in.
12 MR. EBERSOLE: Oh, okay. I see. So it is in
.m
$_) 13 place.
14 MR. THOMAS: Part of the requirements for them to 15 start up was to install the automatic shunt trip in Unit 16 1. It already had been installed in Unit 1.
17 MR. EBERSOLE: I see. Okay. So this is really 18 just a flat on the persistence of this weakness of the UV 19 trips.
20 MR. ROSSI: And again, they are all committed to 21 do it, and it is a matter of the scheduling. It is my 22 understanding now that they are all going to do it at the 23 latest at the next extended outage.
24 MR. EBERSOLE: I am just saying that this is
) 25 really just another exhibit of the consistency of the ACE-FEDERAL REPORTERS, INC.
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5463 02 02 88 merysimons 1 weakness in this design.
2 MR. ROSSI: I would say yes.
3 MR. EBERSOLE: Right. So I would not recommend 4 this to go to the full committee.
5 MR. THOMAS: As a result of the first two initial 6 failures on the 29th -- by the way, I want to touch on the 7 failure that occurred at Kewaunee.
8 When they attempted to meet the requirements 9 specified in the Bulletin 85-02, they again had. experienced 10 this failure of the 20-ounce margin. They dropped down to i 11 16 ounces when it failed to trip at 20 ounces, and it l 12 passed both times with the 16 ounces. They relubricated i (~T l (. ) 13 the device and went back to 20 and tested it and it passed 14 the te s t.
15 MR. WYLIE: .You also six or eight months ago 16 reported to us a problem with the solid state output logic l-17 on the voltage trip, the problem they were having when they 18 tested them and they used the wrong instrument. What did i 19 you do about tha t?
20 MR. ROSSI: I think that is still being looked 21 at. Now it is correct that that particular failure would 22 keep you from actuating either the shunt trip or the 23 undervoltage trip in automatic. Now it is my understanding L
l l 24 that you can still manually trip the breaker, but that was l () 25 a failure in the solid state protection system. As I l
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'in jncrysimons 1 recall, we had sent a notice out and I believe that NRR is 2 still looking at whe ther any. additional improvements in the 3 reliability of the solid state protection system output 4 needs to be done.
5 MR. WYLIE: Well, they use the same output in 6 solid state relays.
7 MR. EBERSOLE: They did the minimum. They 8 overused existing equipment rather than putting in new 9 circuitry.
10 MR. ROSSI: But that failure was caused by some 11 te s ti ng .
12 MR. EBERSOLE: I know, but it exposed the fact (n) 13 that they had a common point of failure for both the shunt 14 and the ---
15 MR. ROSSI: Again I will point out they had two 16 trains of solid state protection, and those are known 17 points that if both trains fail at that point it will 18 de fe a t the automatic trip system. There are probably 19 others in there also.
20 MR. EBERSOLE: Ernie , when you get an ATWS, do you 21 ge t an audible signal that you should have scrammed and 22 have not and you must go to the manual scram 23 instantaneously?
24 MR. ROSSI: To my knowledge, there is not a
() 25 specific enunciator tha t says you have got an outage , but ACE FEDERAL REPORTERS, INC.
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5463 02 02 90 carysimons 1 you will ge t alarms telling you you have lost feed, you 2 have got high pressure or whatever else is occurring. So 3 there should be lots of information.
4 MR. WYLIE: Was there an I&E bulletin issued 5 telling people don' t test this way?
6 MR. ROSSI: No. There was a notice I believe 7 issued -- I am sure there was a notice issued telling 8 everybody about the problem. It was not a bulletin.
9 MR. EBERSOLE: It appeared appropriate at the time 10 that I recall that multi-range testers ought to be 11 outlawed.
12 MR. ROSSI: Well, I think the meters should have
(~)
~ _ 13 been set up for the voltage.
14 MR. THOMAS: The two devices, the two UVTA's that 15 failed on October 29th and November 3rd were later sent by 16 the licensee to Westinghouse for general analysis testing 17 through visual inspection and force measurements.
18 The licensee I understand is going to look at 19 those results and decide at that time whether he is going 20 to do additional testino to enhance his confidence in the ,
21 recommendations coming out by Westinghouse.
22 As I mentioned earlier, and I don' t know whe ther I 23 did, the breakers at both Unit 2 and Unit 1 at D. C. Cook 24 have been refurbished back at the Westinchouse plant back r
(-) 25 in July, and at that time all of the breakers received new ACE. FEDERAL REPORTERS, INC.
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l 5463 02 02 91 Ix )/marysimons 1 UVTA's in addition to lubrication to the breakers 2 themselves.
l 3 MR. EBERSOLE: One of the more fascinating parts 4 of the Salem event was the zeal and eagerness to execute 5 the. manual trip. At Salem he applied enough force to the 6 pistol grip switch to pull it out and knocked the handle 7 off. Was anything ever done about looking at the physical 8 ruggedness or characteristics of the scram switch to be i 9 sure that when you turned or pulled the handle that the i
10 handle wouldn't come off in your hand?
11 MR. ROSSI: I don' t recall if that was addressed.
12 MR. EBERSOLE: It is very embarrassing, in any (k 13 case, to turn the handle and not have the shaft turn.
14 MR. ROSSI: I agree.
i 15 MR. EBERSOLE: And it would be especially so in j 16 this case. I guess he could go to the MG set breakers.
17 MR. THOMAS: In this particular case we are glad 18 that he didn' t do that.
19 MR. EBERSOLE: Oh, yes. Sure. You lose the 20 evidence if you execute shunt trip, yes.
21 Is there any problem here in losing the evidence?
22 The re is no way of recalling the malfunction if you execute 23 a manual trip me thod. Is there no separated sequential 24 indication of which you try first, or do they both go at !
./'T C/ 25 once?
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)ntrysimons 1 MR. THOMAS: Oh, no. They have a compute r 2 printout that will tell you which ---
3 MR. EBERSOLE: Whether it was the shunt or the 4 UV. Then I go back to the premise , and I quess you say you 5 do it by physical intermittent te s t ing ---
6 MR. ROSSI: The testing will recuire a separate 7 verification if the shunt trip is working.
8 MR. EBERSOLE: But that is a periodic sort of 9 thing where you are invoking your reliability between 10 tests.
11 MR. ROSSI: That is a periodic test. But when you 12 get an actual reactor trip, you will not be able to tell
()
/ \
13 which one of them tripped the breaker.
14 MR. EBERSOLE: Any questions?
15 (No response.)
16 MR. THOMAS: The regional follow-up inspections 17 were required in our bulletins and we issued a temporary 18 i :truction in that area. Following the Kewaunee even t , we 19 got heavily involved with Westinghouse. They had some 20 concerns and questions on our bulletins, and by our I mean 21 the NRC bulle tins. We just recently issued a letter in 22 response. In essence what they were asking was a relief 23 from the 20-ounce margin test. They wanted 16. They also 24 wanted the as-found positions that they could lubricate.
(m) .
25 The latest status of the situation is that the ACE. FEDERAL REPORTERS, INC.
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_ Ja rysimons 1 analysis testing that had been done at Westinghause is 2 being discussed this week. Dave Wiggins is the Project ,
3 Manager and he can address it. He is going to meet with ,
4 the licensee this week to find out what the update on that 5 is.
6 That is about what we have to say on it. m 7 MR. EBERSOLE: Ernie , le t me ask you this. This.;
8 point out, this event,. that spring actuated functions, 9 while they appear to work when they are new and clean, can 10 be overridden by static friction on any kind of device, you 11 know, like a CO-2 valve or whatever if it has been sitting 12 in place for a long period of time, it is dirty and the 13 lubricant has hardened and so forth.
14 Was there ever a broad-scope inveytigat bn'myde of 15 this kind of phenomenon where spring actuated, furetions may 16 in fact never have been studied to determine the yargin of 17 force to execute from the normal degraded state? s ,
18 MR. THOMAS: We have expressed this befdre on 19 control switches that can' t ge t back to the neutral 20 position.
21 MR. EBERSOLE: Anything that is spring driven.'As T
22 a matter of f act, this was the first time I ,ove r' heard of 23 an organized analysis where the margin of force was invoked 24 as a requirement of the test mode against sttitic friction r
(/m) 25 f rom old, hardened grease end dirty conditions and 'so\
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-forth. This is the first organized methodical proof
,2 testing of devices that are spring driven to their =
3 emergency position. So you are saying you will look at 4 other switches -at least.
5 Are there any other control functions that are 6 d rive n ---
7 MR. ROSSI: I don' t think we have done a broad 8 look at all similar types of devices, but we do look for 9 this in our not aal test analysis.
10 MR. EBERSOLE: As you know, in valves you have an 11 impact.to clear it in the driving mechanism to get rid of 12 the static friction and the impulse device , and what else
,o
- (-) 13 do you have? There are a number of devices that' try to 14 override static friction. So it is a prevalent problem.
15 MR. ROSSI: We have problems from time to time 16 with scram solenoid valves.
17 MR. EBERSOLE: Yes, that would be a case in point.
18 MR. ROSSI: And we have talked to you about those.
19 There is one other thing. We do have the 20 augmented inspection team report here to give you as an 21 e xample . Region 3 has a copy.
22 MR. dBERSOLE: Okay. We would like to get copies 23 of it.
24 MR. ROSSI: Vince is going to pass them out. q
,- 1
(_) 25 MR. EBERSOLE: Good.
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5463 02 02 95 S jegrysimons-1 Any further questions on this?
2 (No response . )
3 If not, thank you.
4 MR. ROSSI: The next presentation will cover some 5 recent emergency diesel generator f ailures that have 6 occurred at three plants, and this is going to be given by 7 Dave Lynch from the Of fice of Nuclear Reactor Regulation.
8 MR. LYNCH: Good morning.
9 I am Dave Lynch of NRR. I am Project Manager on
~
10 Fe rmi 2. I will be discussing three separate plants, Fe rmi 11 2, Catawba and North Anna.
12 MR. EBERSOLE: Are they all the same diesel
/
(m_) 13 plants?
14 MR. LYNCH: No, they are not. We lump them 15 toge ther because there are three recent events af fecting 16 the diesel generators. TDI is not the only diesel ---
17 MR. EBERSOLE: It is just the one in the limelight-18 is all.
19 ( Laug h te r . )
20 (Slide.)
21 The first two I will address are Fermi 2 and 22 Catawba. They are dif ferent makes. They did have similar 23 problems though with their bearings. Fermi has had the 24 most extensive problems with bearings and I will address
(_) 25 that one first.
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,3
(,)Carysimons 1 You were passed out a slide earlier and you are 2 now receiving a supplemental slide which basically is more 3 recent and is an updated correction of the first slide.
4 MR. EBERSOLE: What is the make of the primary 5 diesels?
6 MR. LYNCH: It is a Fairbanks Morris unit, Colt 7 Industries.
8 MR. EBERSOLE: What is the size and speed?
9 MR. LYNCH: It is about three megawatts and 900 10 rpm.
11 MR. EBERSOLE: Thank you.
12 MR. MOELLER: Your supplementary handout mentions
(/) 13 14 diesels.
14 (Slide.)
15 MR. LYNCH: There are four emergency diesel 16 generators at Fermi 2. Eleven and 12 feed division one and 17 13 and 14 feed division two.
18 This slide I have put up basically to have a 19 precise presentation of what the problem is and what the 20 significance is. Basically what we are talking about is 21 coatinuing diesel failures from January of '85, a year ago, 22 to as recontly as December 27th.
23 The significance of all these problems with the t 24 diesel generators poses the question of reliability of the
() 25 on-si te powe r.
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(_)acrysimons1 The circumstances are similar multiple failures of 2 the Fermi diesels over an extended period of time. The 3 problem seems to be getting a little bit worse with the :
4 passage of time unfortunately.
5 ( Slide . )
6 The f'irst failure that occurred was diesel No.
7 11. It had massive failures. I put down March here 8 because it was in this time frame that the work was 9 accomplished.
10 No. 12 had bearing failures whereby the bearings 11 were extremely distressed.
12 Nos. 13 and 14 were inspected and there was found
(-m
(> 13 _to be some very large scoring on'the bearings which at that 14 time was not considered to be significant.
15 _ Basically we reassembled in November many of the 16 same people on the review team as we had in the January and 17 March time frame.
18 MR. EBERSOLE: Was there a pattern to the bearing 19 failure? Was it in the mains or the rods or the thrusts?
20 MR. LYNCH: It was in the main bearings 21 predominantly on the upper crank line. This is a piston k
22 design and there are two crank lines.
23 MR._EBERSOLE: So it is in the upper se t?
E24 MR. LYNCH: It is predominantly in the upper set.
/^\'
(._,) 25 In March of 1985, for the record, we issued the low-power ACE-FEDERAL REPORTERS, INC.
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-(_)merysimons 1 license on March 20th, 1985 and the full-power license on 2 July 15th of 1985.- When we issued the low-power license, 3 we imposed a license condition predicated on our 4 understanding then of the failure mechanism.
5 MR. EBERSOLE: Do these have any prelube pumps 6 that start before the main engine rolls?
7 MR. LYNCH: It has that prelube pump.
8 Unfortunately at Fermi the recommendation of the vendor, 9 Fairbanks Morris, was that the automatic lubrication system 10 of the air accumulators would push enough oil out of the 11 two-and-a-quarter gallon reservoir through the lowbr crank 12 line up to the upper crank line and down to the last h'
(_) 13 bearing. -There was some concern that that was not a true 14 s ta teme n t .
15 MR. EBERSOLE: That is it pushed from the bottom 16 to the top rather than flow from the top to the bottom. It 17 seems_like it is inve r ted .
18 MR. LYNCH: I think 'we should bring in Fairbanks 19 Morris to discuss that.
20 MR. MOELLER: Did all of these failures occur just 21 f rom the testing? The diesels really never ran for any 22 extended period?
23 MR. LYNCH: I will get to the diesels on slides 2 24 and 3. These failures in 'some cases occurred af ter one (m
(,) 25 hour2.893519e-4 days <br />0.00694 hours <br />4.133598e-5 weeks <br />9.5125e-6 months <br /> and in some cases af ter 100 hours0.00116 days <br />0.0278 hours <br />1.653439e-4 weeks <br />3.805e-5 months <br />.
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( )m2rysimons 1 The failures , the January '85 failures were at 2 that time presumed to be strictly as a result of the 3 inadequately lubricated fast starts.
4 MR. EBERSOLE: And this is all in the upper crank 5 now?
6 MR. LYNCH: Predominantly in the upper crank. I 7 think there may have been one lower bearing that went. The 8 problem is that when you start getting multiple failures, 9 if you have a failure in the upper bearing, you can cascade 10 that into a failure in the lower bearing.
11 MR. EBERSOLE: Sure, right.
12 MR. LYNCH: The presumption is that the upper ys X ). 13 bearings go first and a failure of the lower bearing is a 14 result of the failure of the upper bearing.
15 MR. WYLIE: Are these cast aluminum bearings?
16 MR. LYNCH: They are cast aluminum bearings.
17 MR. EBERSOLE: Is there a particular reason that 18 they pushed the oil to the top rather than letting it run 19 to the bottom like it naturally would?
20 MR. LYNCH: Well, . the particular problem that they 21 have with running is no problem.
22 MR. EBERSOLE: Are you<sure?
23 MR. LYNCH: I think you might ask the question of 24 should they have continuous lubrication.
25 MR. EBERSOLE: They lock the cylinders , don' t
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'ip)marysimons v, 1 they, then and they get oil leakage into the rings.
2 MR. LYNCH: Right. So basically the thought was 3 that with the manual prelubrication, which is nothing more 4 than going over and throwing a switch for manual operation, 5 then it would take about 30 seconds for the oil- to get to 6 the last bearing on the upper crank line.
7 MR. WYLIE: How did you detect the bearing 8 fa ilure ?
9 MR. LYNCH: We ll, the failure of 11 was a trip on 10 low oil pressure. When they looked in the crank case they 11 saw pieces of bearing, piston ring and pieces of piston.
12 It was a massive failure.
,-~.
(_), 13 MR. WYLIE: Did you say you repair it or you 14 replaced it?
15 MR. LYNCH: The bearings were all replaced. You 16 can' t have repairs. When I said repair, I meant repair the 17 macnine by replacing the bearings.
18 MR. EBERSOLE:. Is this a common phenomenon with 19 these opposed cylinder designs that the upper cylinders 20 have trouble s?
21 MR. LYNCH: There have been, and we have just 22 recently learned that at Duane Arnold, which has these 23 units almost identical to those at Fermi 2, did have 24 similar trouble in 1983, which we recently discovered. We g 25 are licensing right now and our staff is trying to find out
(_j .
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-(-)marysimons 1 what the exact vibrating history of all these units are at 2 the other plants.
3 MR. EBERSOLE: You mean all the opposed cylinder 4 designs?
5 MR. LYNCH: Ye s .
6 MR. WYLIE: You mentioned that some of these 7 occurred in a few hours and some af ter a hundred hours. Is 8 it deliberately part of your test program to run power runs 9 for a hundred hours?
10 MR. LYNCH: Ye s , they are. If I can pass on to 11 the next two slide s ---
12 MR. WYLIE: Have you found other problems?
13 MR. LYNCH: Well, the damage has been 14 predominantly to the bearings. Now you recognize when the 15 bearing goes and you have the crank shaf t coming out of 16 alignment, you are going to have damage to the pistons, the
~17 ~ piston rings and so on, but that is considered to be 18 cascading damage as a result of the failure of the 19 bearings, the main bearings themselves.
20 MR. WYLIE: There has been no fatiguing of-21 injection tubing and things like tha t?
22 MR. LYNCH: Not at this time. These diesels have 23 been torn apart very frequently.
24 MR. EBERSOLE: Have these failures influenced the
('T A_/ 25 estimated reliability of AC power on this plant in the ACE-FEDERAL REPORTERS, INC.
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5463 02 02 102 i es Eq_)mcrysimons 1 total context? l 2 MR. LYNCH: Are you asking about in the context of 3 do we have a PRA ---
4 MR. EBERSOLE: Yes, for this particular one.
5 MR. LYNCH: This particular plant does not have a 6 PRA, and as you are aware , most of the plants have not had 7 a PRA.
8 MR. EBERSOLE: Does it have a strong grid?
9 MR. LYNCH: It is in a high industrialized area.
10 I would say speaking in tarms of the industrial Midwest a 11 strong grid. Speaking about those plants specifically, it
'12 has two separate li,'es coming in which are physically r'\
. (,) 13 se pa ra ted .
~14 MR. EBERSOLE: There was an elaborate study that 15 got lost in the paper mill about the proposed frequency of 16 testing of diesel generators such as this versus the 17 reliability of the grid. Do you recall the one I am 18 talking about?
19 MR. LYNCH: I am not aware of that.
20 MR. EBERSOLE: Ernie,'you know the one that we did 21 where you were going to impose 'more frequent tests on .the
'22 plants that had an apparent lower reliability of total AC 23 power?
24 MR. ROSSI: I am not familiar with that.
() 25 MR. EBERSOLE: I think it got lost in CRGR.. I was ACE FEDERAL REPORTERS, INC, 202-347-3700 Nationwide Coverage 800 336-6M6
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()marysimons1 just wondering where this plant stood in that spectrum.
l 2 MR. ROSSI: This is Alan Rubin from NRR.
3 MR. EBERSOLE: Was it down at the bottom?
14 MR. RUBIN: I am not sure specifically where this 5 plant fit in. We have a lot of data that has been 6 collected. The program you are referring to I think was 7 part of B-56, diesel generator reliability in which a 8 generic letter was sent out by the NRC, No. 84-15, 9 requesting diesel power plants report their reliability.of 10 their diesel generators. I don' t recall specifically the 11 numbe r f rom Fe rmi . The ranges were from no failures in a 12 hund red tests to 90 percent reliability or a little less.
()
,~
13 Generally the average range was about 98 percent 14 reliability for diesels.
15 You referred to the program that was sent out for 16 comment. If your diesels are exhibiting a certain number 17 of failures, you test them more frequently to see that yon 18 have fixed the problem. That went out for comment and NRC 19 received comments back from licensees saying there are
-20 other ways to address the issue than just testing for 21 statistical purposes in looking at the root causes of 6
22 problems and failures. That particular generic issue has 23 not been comple ted ye t. The staff has received comments 24 and they are being evaluated.
(m) 25 It will be addressed in part. It is incorporated 9
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(~n 1-)merysimons 1 into USA-44, station blackout, which I will describe for 2 you later.
3 MR. EBERSOLE: Okay.
4 MR. LYNCH: I think it is important to put on the 5 record tha t we are not talking here about the failure to 6 start.
7 MR. EBERSOLE: Oh, yes, the failure to run ---
8 MR. LYNCH: The other is the failure to continue 9 to run.
10 MR. .EBERSOLE: Right, sure.
11 MR.-LYNCH: There has been no history of failure 12 to start when the bearings go.
r%
's) 13 As I said just a few moments ago, we have tried to 14 assemble the same people , the same team at the site in 15 looking at that so we can correlate both in terms of living
-16 memory and observation what was done in the last January 17 and March time frame and what is being done in the November 18 ' and December time frame.
19 Region 3 is basically carrying the lead on this 20 investigation now with_ support from NRR. The licensee has 21 re tained a number of consultants, including Fa ilure 22 . Analysis Associates.
23_ MR. EBERSOLE: What is the tolerance of this plant 24 to sustain a total loss of AC power for "X" hours?
25 MR. LYNCH: Well, it is a boiler, and I would ACE-FEDERAL REPORTERS, INC.
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()marysimons1 argue -that a boiler is a fairly stable plant.
2 MR. EBERSOLE: Okay, it is a boiler.
3' MR. LYNCH: Franklin Institute has been examining 4 the bearings for us. In particular we have observed there 5 has been particle pickup. The preliminary conclusion of 6 Franklin is that particle pickup is seen on the bearings 7 themselves and our concern is that it may be one of the 8 contributing factors. It may be due to the compound used 9 in the break-in process. So there is some concern right 10 now that the break-in process has some fundamental 11 weaknesses in it.
12 MR. EBERSOLE: These systems all have full-flow
_() 13 oil systems, don' t they?
14 MR. LYNCH: Ye s , they do.
15 MR. EBERSOLE: In the course of doing what you are 16 saying, examining the particle pickup, is there an 17 organized and carefully monitored process of picking up 18 lubricant particles that are in the - lubricant itself and 19 watching the accumulation and avoiding the ultimate 20 catastrophe?
21 MR. LYNCH: Well, we imposed a license condition 22 in the low-power and full-power license to address this 23 question and it involved such items as a spectrographic 24 analysis of the oil to do exactly that. Now that means
(). 25 that you could pick up particles at the atomic level.
1 i
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5463 02 02 106 As/ marysimons 1 We also imposed a requirement for a detailed 2 examination for a very short period of time on the failures 3 themselves. I have to be quite frank and honest and say 4 that program never predicted the failures that we observed.
5 MR. EBERSOLE: Is there any way to pick up the 6 metallic particles once they begin to aggregate to a 7 teaspoon-full or wha tever?
8 MR. LYNCH: Well, let me go back to diesel No.
9 11. After the loss of failure of the major components in 10 tha t machine , if you took out the filter you could see the 11 flake size particles on the fil te r .
12 MR. EBERSOLE: That is done at periodic intervals?
( 13 MR. LYNCH: That was done at periodic intervals, 14 but in the problems that occurred in the November / December 15 time frame, the oil monitoring system did not in any way 16 predict the failures of these machines.
17 MR. EBERSOLE: Well, in the meantime , what is 18 going to happen at Fe rmi? What is the power picture at 19 Fe rmi?
20 MR. LYNCH: I will get to tha t in a mome n t , but I 21 can answer it now for you. The license was issued on July 22 15th, as I said earlier. On the af ternoon of July 15th we 23 were made aware of a problem of premature criticality. On 24 July 16 th, on the morning of July 16th we issued an action
() 25 letter which said basically do not go above five percent ACE-FEDERAL REPORTERS, INC.
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(,jmarysimons1 powe r. Tha t le tte r is s till in e f fec t. So the power has 2 been restricted during this time period to five percent.
3 The plant was shut down in early October and had L4 operated from July 16th through I think the first week in 5 October at a power level not to exceed five percent 6 basically. They were still operating in a low-power -
7 license phase ef fectively.
8 The accumulated power in that time frame probably 9 averaged around 2.5 to 3 percent during that time frame of 10 mid-July to early October. I would assume at this point 11 that all the short-lived fission products have decayed and 12 there is very little long-lived fission products in the re .
-() 13 MR. EBERSOLE: So they have been operating at a 14 very low load.
15 MR. LYNCH: They have not operated the turbine 16 generator. They have synchronized it with the grid, but 17 they never connected it to the grid. At low-power levels 18 ~you have to worry about the grid failing.
19 MR. EBERSOLE: Is this outage really then due 20 primarily to this reason?
21 MR. LYNCH: This outage came about for a number of 22 reasons.
23 MR. EBERSOLE: Okay.
24 MR. LYNCH: Basically the outage that occurred in These
.( ) 25 October had nothing to do with diesel generators.
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'msrysimons 1 ge nerator failures occurred about a month af ter the 2 - outage. The outage was to install qualified equipment and 3 to make improvements in the fire protection system all of 4 which were conditions in the licence.
5 MR. EBERSOLE: So we don' t have any standing 6 par'icular hazard at this plant now?
7 MR. LYNCH: That is quite right.
8 MR. EBERSOLE: All right.
9 MR. LYNCH: It was thought when this slide was 10 made up that the apparent cause may be due to inadeauate 11 lubrication and that still may be a cause due to the me thod 12 of break-in.
- r; isk 13 At the time this slide was made up, which was ,
14 early December, the licensee has proposed a test program on 15 diesel generator No. 13 which would do a certain number of 16 prelubricated cold fast starts and a certain number of 17 unprelubricated fast starts in a certain number of hours of 18 running, the idea being that if they are then torn apart 19 atd examined and no damage was found, that could be used as 20 a benchmark for how many prelubricated starts you could 21 have and unprelubricated starts you could have.
22 MR. EBERSOLE: Well could it be said then that 23 this is just another evolutionary problem here. It happens 24 not to be TDI's, but these opposed cylinder designs and it
-t')
(s 25 is in the course of being resolved?
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)m2rysimons'1 MR. LYNCH: At this point I have to be honest with 2 you that we don' t see a resolution right now. We are 3 working onuit, but we don' t have it.
4 MR. EBERSOLE: Right.
5 MR. LYNCH: We did issue a 50.54(f) le tter on 6 December 24th, a Chris tmas present, specif.ically requesting 7 additional information about all the problems they have.
8 This is not the only problem them have.
9 MR. EBERSOLE: Well, the other plants that operate 10 with these diesels, have they been issued orders to monitor 11 the lube oil , e t ce te ra , e t ce te ra , e t se te ra and de tec t 12 incipient f ailure s?
/~
(_)T 13 MR. LYNCH: No, they have not.
14 MR. EBERSOLE:- Well, why haven' t they been?
15 MR. LYNCH: Be cause te <iite we can only identify 16 this problem unique to Fermi.
17 MR. EBERSOLE:. Is this design unique?
18 MR. LYNCH: If it was design unioue we would have 19 to issue orders to the other plants, but we have not been 20 able to identify it as design unique.
21 If I can get to the next slide, I can discuss some 22 of those questions.
23 One last word. I would hope you would ignore this 24 because thic was made up prior to further additional t l'
' '(_) 25 information. So this slide is incorrect. Having come back ACE-FEDERAL REPORTERS, INC.
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'5463 02 02 110
)()mnrysimons1 'from a few weeks of vacation, I didn' t have a chance to 2 update that slide. But the following slides prepared by ,
3 the region give you a better chronology.
4 (Slide.)
5 As I said, this gives you a chronology and status 6 report but not a resolution.
7 There was extensive damage to No. 11. It was a 8 massive failure. When diesel No. 12 was torn apart and
.9 inspected it was found that it had similar problems to No.
10 11. It had extremely damaged bearings, but not any massive 11 failure of the other components.
12 Thirteen and 14 were torn apart and there was very
[)' 13 light scoring observed on the bearings in 13 and 14, but it
-14 was not considered as severe damage or indicative of any 15 impending failure.
16 About a month af ter the plant was shut down for 17 doing further fire protection work and_ doing the-18 environmental qualification, there was extensive damage i-19 that occurred to diesel generator 13.
t.
20 During that time period it had had a limited
- 21 number of surveillance te s ts . So what had been seen here 22 was-a relatively good machine, and here is No. 13 with i- 23 extensive damage, which caused some concern because at this 24 point the license condition was in force and the machines
() 25 were being manually prelubed prior to surveillance testing.
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.(_)marysimons 1 Similar damage was found on No. 11 to the 2 bearings. No damage was observed on diesel generator No.
3 12. No. 14 again had some light scoring 4 Moving on to December 23rd, just before Christmas, 5 af ter 16 hours1.851852e-4 days <br />0.00444 hours <br />2.645503e-5 weeks <br />6.088e-6 months <br /> of running with bearings that had been 6 replaced, new bearings, it was found that there was 7 extensive damage to a number of bearings on No. 11, which 8 mean t it wasn ' t the starts themselves doing it, but just 9 the running process itself.
10 In that same time frame a low-lube oil viscosity 11 was found on diesel generators 12 and'14.
12 MR. EBERSOLE: How can that be when I presume they (s
q_) 13 are all loaded with the same oil?
14 MR. LYNCH: Tha t is a good question. The re is 15 some concern that that particular oil does not maintain its 16 viscosity through wear.
17 MR. EBERSOLE: Is there like a OA on the oil 18 itself?
19 MR. LYNCH: I would have to say at this point that 20 I presume there is a OA on the oil itself, but the real 21 question is has the oil gone through an extensive te s ting 22 program- to verify that its maintains its viscosity.
23 Given the natura of the design of bearings, the 24 most impor tan t factor in that is the surface roughness of
(
.o) '25 the bearing and the viscosity itself. Those two factors ACE-FEDERAL REPORTERS, INC.
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5463 02 02 112 A )marysimons 1 concern whether the bearing will survive or not.
2 MR. EBERSOLE: Do they change out the oil on all 3 diesel generators at one point in time?
4 MR. LYNCH: I can' t answer that. I would suspect 5 they may have changed some oil, but not all oil.
?
6 MR. ROSSI: The answer from Region 3 on that is 7 yes.
8 MR. EBERSOLE: Well, Ernie, why are they permitted 9 to do that? That is a good way to stop them all.
10 MR..ROSSI: I don' t know that we have any 11 requirement on that.
12 MR. EBERSOLE: Staggered service of maintenance is n
- (,) 13 a criterion that is universally required.
14 MR. LYNCH: Your poin t is well taken.
15 MR. GREEMAN: If I can interject. I think part of 16 the problem with the oil replacement at Fermi was when they 17 got themselves in trouble initially with the diesel 18 generators and they started this rather extensive te s t 19 program.
20 As Mr. Lynch pointed out, the Fermi diesels are
- 21 unique , and to the best of our knowledge , it is the only 22 plant in the country that uses that particular brand of 23 oil. It is also true that we have found out now that the 24 manufacturer of that oil has discontinued that particular
( ) 25 brand. Now all the specs on the oil are exactly-the same ACE-FEDERAL REPORTERS, INC.
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f5'4'63 02 02 113 marysimons 1 as a dif ferent brand of oil .that currently most other 2 utilities are using.
-3 We have ' a sample of that oil out for analysis,. but 4 wel don' t have ' the results back yet. We think at this point
.5 in-time that- the viscosity problems may be related to the s
6 fact that Detroit Edison Company also runs their oil a 7 little bit warmer than anyone else does, but that i
8' evaluation'is also still out for analysis.
~
9 MR. EBERSOLE: Well, the lube oil if it is 10 replaced at one' point in time could certainly be a common ,
I~
11 1 - mode ~ failure . ,
12 MR. GREEMAN: Yes, certainly, cnd the re is a 13 quality assurance program that is in effect. The la tes t l 14 theory just before I lef t Region 3 to come to Washington,
. 15 one of the consultants believed that there was a problem 16 with the Joil on one diesel generator related to foreign 4
17 materials that was in the diesel generator.-
18 MR.'WYLIE: Did it meet the manufacturer's
+
--19 recommendations?
20 MR. GREEMAN: Yes, J sir, in all cases, as. best as 21 we -have 'been able to determine at this point, but Franklin
' 22 Ins ti tute is stil1~ working on that. They also have samples 23 of- the preconditioner and the lapping compound that was 24 used with these diesels before we reassembled them.
, ) 25 MR. EBERSOLE: Has this -plant ever had a station L
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x /marysim'ons 1 blac kou t?
2 MR. LYNCH: No. The re is one point that I would 3 1.ike to make that I think is important to make. The specs
'4 can sta te the initial requirements on viscosity, but the
-5 real question though is does it hold up over a period of 6 time. If you run it for 100 hours0.00116 days <br />0.0278 hours <br />1.653439e-4 weeks <br />3.805e-5 months <br /> is the viscosity still 7 the same?
8 The experience on 12 and 14 indicated that samples 9 taken out of the crank case that the viscosity has fallen ,
10 significantly enough to compel the licensee to shut down 11 the plant and start worrying about that oil.
12 MR. EBERSOLE: How do you detect viscosity on N 13 line, just by sampling?
- . 1(,/ -
14 MR. LYNCH: Just take a sample out of the crank 15 case.
16 MR. EBERSOLE: You run a range te s t , okay.
17 MR. WYLIE: Is FAA involved in that investigation 18 also?
19 MR. LYNCH: FAA is involved in every aspect. The y 20 have also been deeply involved with TDI, which you may be 21 aware of.
22 MR. WYLIE: Ye s .
23 MR. LYNCH: On December 27th, which is the most
'24 recent scenario on damage, there was additional damage r
( 25 found to the bearings in diesel No. 11 af ter about one hour ACE FEDERAL REPORTERS, INC.
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5463 02 02. 115 (q,)murysimons1 of running time. They ran it for one hour and put . in a 2 fuel gauge , which is a go/nc-co test and it failed the 3 go/no-go test, which is the first indication of a bearing 4 failure.
5 Mr. Greeman mentioned that diesel generator 13 6 showed some evidence of me tal pickup. It was my 7 understanding that this may have been brass. If it was 8 brass, it didn' t come from the basic machine itself, but 9 perhaps out of one of the tube lines.
10 MR. ROSSI: Dave, I wonder if you could.give the "11 bare essentials on the remaining North Anna and Catawba.
12 We are beginning to ge t into a time problem.
!j).
. i 13 MR. LYNCH: Fine. I would prefer to do that.
-14 (Slide.)
15 Ca tawba had basically, as it says, repea ted 16 failures of bearing No. 7. The significance is still the 17 same, the reliability question of the outside power.
18 ( Sl ide . )
19 This is a generic applicability to those plants 1
20 listed up there. The sequence of events is that in 21 preoperational testing af ter doing a run there was an 22 inspection done , a tear-down inspection, and it was found 23 out that the bearings seemed to be all right.
24 On Novembe r 20th , however , there was a failure of
() 25 bearing No. 7 af ter about five hours of operation. The re ACE-FEDERAL REPORTERS, INC.
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( ,)me.rysimons 1 is a postulated cause , but tha t is not clear 'as to whe ther 2 it is correct or not.
3 MR. EBERSOLE: What is the make of this diesel 4 generator?
'S MR. LYNCH: TDI.
6 MR. EBERSOLE: Okay.
7 MR. LYNCH: Following that bearing failure of No.
8 7, seven out of ten bearings were inspected. Three were 9 not, one, two and four, and five out of the seven were 10 replaced even though they were lightly scored. That was an 11 a ttempt to avoid future problems.
12 Then in early December there was another failure
- -z (~),
g 13 of bearing No. 7, and the te s t wa s s topped . The exact 14 cause is not really yet known. The re is a follow-up going 15 on. Basically this is still an ongoing investigation much 16 as Fe rmi is.
17 MR. EBERSOLE: In the meantime, whct is the 18 integral status of the TDI diesel problem in the context of 19 AC power supply reliability? We know lots about TDI 20 diesels now. There are stacks of paper six feet high.
21 MR. ROSSI: The sta tus , I don' t know that we have 22 anybody here that can tell you anything on the status of 23 that.
24 MR. EBERSOLE: Are they running with the TDI's as
()
/
25 support?
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?s d )merysimons 1 MR. ROSSI: Catawba is running, isn' t it?
2 MR. GREEMAN: Unit I had got TDI's.
3 MR. ROSSI: Catawba, Grand Gulf and River Bend.
4 MR. EBERSOLE: I am just trying to get a picture.
5 How we running with TDI's.
6 MR. LYNCH: Catawba 1 is running with TDI's.
7 MR. WYLIE: As you will recall, we had a 8 presentation by the TDI task force chairman, Carl 9 Berlinger, several months ago, and his report was that the 10 TDI diesels were way up in the 99 percent reliable based on 11 their testing that had been done to date.
12 - MR. EBERSOLE: On running, yes.
13 MR. WYLIE: Well, all of these machines, as I 14 recall, most all of the TDI diesels have been required to 15 run a hundred hours at full load af ter they go through the 16 startup. I think if you really look at those versus these 17 other diesels , they have been tested more than the other 18 manufacturers of diesels.
19 MR. EBERSOLE: So the TDI's don' t have the cloud 20 hanging over them that they did for a while?
21 MR. WYLIE: They shouldn' t have with all the 22 programs they have been through.
23 MR. MICHELSON: Well, haven' t there been a number 24 "f TDI failures since that time?
). 25 MR. WYLIE: . No , not a f te r the y we n t through this ACE-FEDERAL. REPORTERS, INC.
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(,)msrysimons1 development program and went through this test program.
2 MR. MICHELSON: I thought the reports showed 3 several in the last three or four months.
4 MR. WYLIE: If you look at this one here , Catawba, 5 this is part of that same program during startup. This is 6 the startup test associated with that program just like the 7 first unit we had. The first unit passed and, as far as I 8 know, has been very successful in those first few units.
9 The problems like this No. 7 bearing, it is a 10 postulated support, and I am not sure what the nature of 11 failure is, whether it is a crack or wipe or whatever it 12 was.
7
(_/ 13 MR. LYNCH: On Ca tawba the failure mechanism is a 14 crack through the minimum wall section.
15 MR. WYLIE: Was it found in tear-down or was it 16 found i n ---
17 MR. LYNCH: The 'first one was found in the te a r-18 down. I am not sure. We have the Project Manager for 19 Catawba here who could perhaps address how the second 20 failure was discovered.
21 MR. WYLIE: This is the first bearing failure that 22 I have known of in the TDI diesels af ter they went through 23 this refurbishing program of a crack type. Now the I l
1 24 Shoreham machines, if you recall, that is how they found I
() 25 the original problems with cracks, and that was because of ACE-FEDERAL REPORTERS, INC.
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.5463 02'0:2 7 119 kmarysimons1-the ' overhang of the bearing outside the support. Tha t is a 2 desf gn problem, and that is the reason I sort of questioned 3 this because unless the bearing was manufactured wrong to
- 4. begin with for that particular shell. !
I 5 MR. EBERSOLE: But didn' t they fix those bearings? -
6 MR. WYLIE: Oh, yes. . Tha t is what is peculiar.
c 7 These particular machines, these big V-16 machines, those 8 are not a new design ~ and those bearings were designed for
~
9 many machines in operation. But now the Shoreham machine 10 was a new design and it was a design error, and it was an 11 overhang of the bearing shell where it was unsupported that-12 - caused the cracking. That is why I sort of question this
' p) (_ 13 particular one here.
l 14 MR. LYNCH: There is . some question about the i
! 15 proper support of bearing No. 7. Did you wish to fol-low up d
16 on that question about the 'second bearing failure?
17 ~ ( No re sponse . )
18 (Slide.) -
19 The last diesel generator problem is something you can get
[
20- your hands on because it is a 'readily identifiable cause.
21 Basically the end of the nut was not square -with t
5 22 the shaf t of the thread line , and of course when you 23 tighten up such a nut it puts the bolt into an unanalyzed 24 condition and puts bending stresses on it which otherwise !
() 25 would not be there .for a well manufactured bearing.
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's / marysimons 1 It is a' common mode failure if they got out into l
2 the industry and they were sent to a number of plants, as 3 you can see below. Inducing stress beyond the design limit 4 is basically putting stresses on the nut and on the bolt, 5 which is basically bending induced by that.
6 MR. EBERSOLE: How did they find that deficiency?
7 MR. LYNCH: Somebody at the vendor's plant 8 observed that Part 21.
9 MR. EBERSOLE: You mean he was checking screw 10 alignmen t?
11 MR. LYNCH: I don' t know, but it was found at the 12 vendor's plant.
- 13 MR. EBERSOLE: I see.
14 MR. WYLIE: But now these machines have been in 15 operation a long time.
16 MR. LYNCH: Nominally these bad nuts were not 17 installed in any machine , but they were made in a batch 18 that happened to be a bad batch which happened to be a 19 failure of OA.
20 MR. EBERSOLE: Is that visually detectable when 21 you try to assemble the cap that it goes on in the bias?
22 MR. LYNCH: If you are perceptive, yes. If you 23 just had a rush, probably not.
24 MR. WYLIE: I see you noticed spare parts only.
25 MR. LYNCH: Well, it turns out tha't that is what ACE-FEDERAL REPORTERS, INC.
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(_)merysimons1 was told, but you can see here a factory assembler on a new 2 engine picked it up, and again, as I said,,itisabatch - _,
3 problem. .-w ,
7 4 The Part 21 was sent out. However, f( was found g
15 - to be installed in Diesel GenerK1 1-J at North Anna prior 6 to the start of the plant. So it could have represented a '
7 problem in an operating plant. Fortunately, the Part 2f 8 notification action worked and caught the problem.
9 MR. EBERSOLE: In doing maintenance work on the 10 d ie sels , is that a ritual that you now go through to check.
11 squareness of the makeup?
12 t1R. LYNCH: I can' t address that, but I would hope 7"N
!%,) 13 that the information notices sent out bring that to the 14 attention of the utilities.
15 MR. ROSSI: I don't think that that would be done 16 in every case without people knowing about this particular s
17 problem. -
18 Mk. EBERSOLE: I would expect a mechanic 'would d ,
19 that routinely, wouldn' t he?
20 MR. ROSSI: It depends on the skill of the 21 particular person. ,
22 MR. LYNCH: There are mecnanics and there are 23 mechanics.
24 ( Laug hte r . )
(Gj 25 MR. ROSSI: Okay. Can we continue on. The next ACE-FEDERAL REPORTERS, INC.
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5463 02 02 122 (3_/marysimons 1 one is an event at McGuire, Units 1 and 2 where a problem 2 with the instrument air system caused loss of both plants 3 from power. This presentation will_ be given by Joe Giitter
-4 from the Of fice of Inspection and En forceme n t .
5 MR. MOELLER: While he is beginning, I noticed and 6 I wondered if the staf f had considered it worthy of 7 discussion. On December the 18th there was a loss of 8 station air at Sequoyah where the spent fuel pool water 9 level went down due to that.
10 MR. ROSSI: I remember the event. It is my 11 understanding that the spent fuel design is such that they 12 couldn' t have uncovered the fuel no matter how far that
/^N
(_) 13 we n t down .
14 MR. MOELLER: So in that sense it is not 15 critical. Okay. Thank you.
16 MR. ROSSI: WO are monitoring in general problems 17 with air systems. Robbie Singh is here who follows those ,
18 and we look at them from the standpoint of all air system 19 problems and ' the kinds of things they are causing on-20 plants.
21 MR. MOELLER: Thank you. Well, this one was of 22 particular interest to me because it is the type of event i 23 that Carl Michelson a year or so ago predicted in one of 24 our subcommittee mee tings.
O 1( ) 25 MR. ROSSI: Well, air systems it turns out are ACE-FEDERAL REPORTERS, INC.
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' )marysimons 1 very1important systems and due result in lots of problems
'2 .in plants and we are following those in a more global
.3 sense.
4 Go ahead, Joe.
'S MR. GIITTER:. As Mr. Rossi had indica ted , I am Joe 6 Glitter of the Events Analysis Branch of the office of
- 7. Inspection and Enforcement.
8 ( Slide . )
u 9 Today I am going- to discuss an event that occurred 10 at McGuire Units 1 and 2 on November 2nd, '1985.
11' What is interesting about this event is the fact
'12 - that . a non-safety related system, a single failure in a non-IO'
- (,f- 13 safe ty related. system caused a safe ty challenge to both 14 :McGuire's Units 1 and ;2, or I should say a challenge to 15 safe ty systems.
16 The event occurred when a section of- braided 17 flexible pipe at the discharge of' one of the Einstrument air 18 compressors failed at a ruptured seam.
19 Now because there were no check valves -at the 20 discharge of these instrument air compressors, it allowed 21 the instrument air system to depressurize. This instrumen t
~c 22 air system is shared by both Units 1 and 2. So it caused a 23 simultaneous-loss of instrument air in both units.
24 On the loss of instrument air as the pressure 25 decrea sed , the main feed flow control valves started ACE-FEDERAL REPORTERS, INC.
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( Jncrysimons 1 closing down. This of course reduced the flow of feedwater 2 to the steam generators.
3 The operators got steam generator deviation alarms 4 and attempted to increase feedwater flow to the steam 5 generators by opening up bypass valves. But because these 6 bypass valves were also air operated, the valves did not 7 respond.
8 Not long- af ter that, one of the main feed pumps in 9 Unit 1 tripped on high discharge pressure , and about a 10 minute af ter that point Unit 1 tripped on low-low steam 11 gene ra tor' level . Unit 2 tripped about five seconds af ter 12 Unit 1 again on low-low steam generator level.
G i s ,) 13 On low-low steam generator level you get an auto 14 start of the aux feed system, but because the aux feed flow 15 control valves are also air operated, they went full open 16 causing excess flow ~ to the steam generators.
17 The only means the operators had to control the 18 flow of aux feedwater to the steam generators was to start 19 and stop the pumps. Fortunately, they restored air in 20 about eight minutes because they went down and they 21 isolated the af fected line that the rupture occurred on and 22 that took them about eight minutes. They sent somebody 23 down there right away when they realized when they had an 24 enunciator that told them that they had low air pressure in
.c x_) 25 the instrumen t air system.
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(_Jmarysimons 1 Unit 1, in addition to tripping, had a safety 2 injection that las' for about 10 minutes until it was 3 secu red . There arc several reasons why safety injection 4 occurred in Unit 1.
.5 The first problem was their pressurizer heaters.
6 Bank "A" of the pressurizer heaters were unavailable for
-7 about one and a half minutes. Apparently the oparators had 8 selected out Bank "B" because they didn' t feel they needed 9 both banks.
10 -In the mean time Bank "B' pressurizer heaters 11 failed to energize because of a failed relay. So they were 12 without pressurizer heaters during a good portion of the bue .13 transient.
14 Another feature was that the steam loads were 15 higher than normal. The reason 'for this is that they had 16 three steam line PORV's open and three code safety valves 17 ope n . - One of the code safety valves actually stayed open-18 for about ' three and a half minutes.
19 In addition, on loss of instrument e.ir, about 22-20 inch main steam drain line valves opened and that caused an-21 increase in steam flow.
22 The last factor that may have attributed to the 23 depressurization is the fact that even though the 24 pressurizer spray' valves go closed on loss of air, there is
'O
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b /marysimons c1 heaters 'what little : pressurizer spay there was. would have
~
- 2 also contributed to 'the cooldown 'and depressurization.
3 The Unit . 2 ~ operators recognized the problems at -
4 Unit: 1 and they secured the tworeactorcoolhntpumps.that 5 . provide the driving head for the ' pressurizer spray. . In 6 addition,. they .didn' t have any heater problems in Unit 2, 7 and 'as a result they did not go below the safety injection
-8 set point of 1845. I believe they only went down to 1904.
9 Other than the above-mentioned failures, all other 10 plant systems . performed as expected for this type of 11 . transient.
12 The cooldown for Unit 1 was 86 degrees for-the
- D
. A,r .. 13 transient, and the cooldown for Unit 2 was 74 degrees for-14 the . transien t.
TP 15 MR. EBERSOLE: May.I ask a question?
'16 MR. GIITTER: Ye s .
17 MR.-EBERSOLE: The main thing this. event -flags for e
. 18 me"are there is no competent system interactive studies 19 'made.at this-point because it is a common element of such L20 studies to consider - the . loss of instrument air especially.
' ~
21 when it is not safe ty grade.
122 And then if it loses generator power, it is an
, 23 embarrassing. and costly event that may be done by a $2 b 24 device some place. It shouldn' t be pe rmitted to do' it.
( 25 .That'is the first stags. The second is is: there a safe ty ACE-FEDERAL REPORTERS, INC.
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. lmarysimons 1 problem or challenge , and here clearly there is.
2 , So what I-see here is a generic implication that c
- 3 there is no compe ten t system interactive study that has 4 looked at this plant at large. Am I correct?
5 MR. GIITTER: I have to agree with you on that.
6 MR. EBERSOLE: Well then why don't we enforce the 7 fact that they do tha t, Ernie?
w 8 MR. ROSSI: Well, you know, again we have systems 9 interaction unresolved safety issues, and then we are 10 looking at instrument air systems ---
11 MR. EBERSOLE: I know, on and on and on.
12 MR. MICHELSON: There are design requirements that g
(_) 13 non-safety systems shall not in any way jeopardize safety 14 systems. That is one of your GDC's. So we don' t need to 15 talk about unresolved safety. issues or anything else. Just 16 fix the problem.
17 MR. ROSSI: Well , le t me poin t out that what this 4
18 did is the loss of the air. system tripped two units and it 19 required the need for various safe ty systems which 20 performed the job that the safety systems were supposed to 21 do. So the air system didn ' t interfere with the safe ty 22 systems performing the job they were supposed to do. But 23 what it did do is it challenged the safety systems that 24 caused a bunch of problems on two units at 'the same time Oxy 25 that were 'relatively complicated, and it challenged the
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128 k_)mnrysimons 1 safe ty systems and the operator's ability to handle it.
2 But as far as I know, I don' t know that it 3 actually violated any of the regulations anywhere. So, you 4 know, it comes back to the poin t ---
5 MR. MICHELSON: Well, tha t may be right.
6 MR. ROSSI: --- it.comes bgck to the point of non-7 safety related instrument air systems that are currently 8 outside of our general scope within the regulations, but we 9 are down here telling you about it because it did create a 10 significant problem in my opinion.
11 MR. EBERSOLE: It also brings out the fact that 12 the regulations don' t per se bring safety. They j us t se t 13 rules which are nice bottom-line requirements.
l 14 MR. ROSSI: I don't know that I would quite agree l
15 with that. They have limits as to how far they can go, and 16 . when you ge t back into the non-safety related stuf f, wo 17 rely on the licensees to look at that stuff carefully l l
18 themselves.
19 Now, as you can see, there were a number of design 20 features here that at least are questionable. The re is the 21 lack of the check valves. There is the tying of the two 22 units to a common system and there are a number of problems 23 that one would have thought the licensee would have had a 24 high interest from just an economic standpoint in making
.(qs . 25 sure they weren ' t there .
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V marysimons 1. MR. EBERSOLE: Well, the economic standpoint is E
2 'always paid for by the ratepayers. The stockholders don' t 13 lose _any_ money when this' happens .
1 4 MR. REED: Jesse, I have been listening for 25 5 years' to one designer talk about the fact that controlled 6 :
air is not a required system for the unit to, le t's say,
~
-7 and he used to use the term " fail safe" and take care of 8 itself with -the safety systems.
9 I am ~ sort of happen this incident occurred, and I 10 don't worry.so much_about the challenge to the safety 11 systems that people talk about. I worry about whether or 12 not 'the safety systems and everything went as they are O
~s / 13 supposed to - or whe ther there is some problem .with respect t
14 to the challenge having occurred. I like to see rods drop
'15 once in a while. The challenges expose vulnerabilities.
16~ So I throw away challenges to safety systems, and
-17 I don' t pay much attention to7that. I am happy to see that 18 --- a nd I know one designer has _ beer, flawed at length with -
i' 1 19 -respect- to controlled air and controlled air systems, .and
-20 - you have got to face the fact that controlled air systems
! 21 just are spaghe tti all over the place. And the fact you 22 didn' t have a check valva - here doesn' t mean you can' t' dump 23 the whole system .on a 2-inch line out some other place. It 24 might dump slower. - But it is spaghetti.
- I h 25 I . don' t -be11cve controlled air can ever be a ACE-FEDERAL. REPORTERS, INC.
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('y
.( )m2rysimons 1 safe ty . grade and protect. and compartmentalize and all these 2 kinds of things that we talk about. I believe controlled 3 air, the utilization of controlled air, we have to accept 4 that it is a hell of a nice instrumentation system. It 5 does a lot of things and moves a lot of valves and so 6 forth, but that it will fail. I have to a this point in 7 time say hey, it happened and it took care of itself.
8 MR. .EBERSOLE: Was this plant equipped with 9 accumulators which provided an stored volume of air for 10 critical functions?
11 MR. GIITTER: They have retainers, but for the 12 most part they have check valves in places where they need
,Q
!) 13 check valves. If the valves fail safe or fail as is, I 14 believe the only place where they would have accumulators 15 would be something like a main steam isolation valve.
16 MR. REED: Do they have accumulators on the 17 PORV's?
18 MR. GIITTER: I don' t know if they do or not.
19 MR. ROSSI: Well, the PORV's, don't forget, are 20 not safe ty related with respect to opening if you need 21 them. So they probably don' t have them.
22 MR. REED: Well, they have been upgraded since 23 Three Mile Island to have accumulators on a lot of PORV's.
24 MR. ROSRI: They may have them. Now the auxiliary
(~,,
- (,) 25 feedwater . valves here failed opened on the loss of air, ACE FEDERAL REPORTERS, INC.
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-( ,emerysimons 1 which in general says that is the preferable way because l
i 2 you turn' on all the auxiliary feed. Of course, then they 3 have to determine how they are going to throttle it back 4 because they are in general going to have too much if 5 everything works.
6 MR. EBERSOLE: Did they throttle it back with air 7 ~by any chance?
8 MR. ROSSI: Well here I guess they turned the 9 pumps on and off and eventually got the air back. I 10 believe that they could have. I believe they could have 11 gone out and used manual valves somewhere to throttle it 12 .back.
I -13 MR. REED: Some people have a DC motor operated 14 valve that is not supposed to use a control valve to 15 throttle it.
16 MR. ROSSI: That is true, too , - ye s . They may have 17 had more. than they .actually used here. I don' t know. But 18 in general we talk about this with respect to Rancho Seco, 19 this system, the auxiliary feedwater system is required for 20 decay heat removal, but it also creates problems when we 21 ge t too much of it. So you have this balancing-thing.
22 Here they have chosen to open them all wide 'when 23 you lose the air, and then they rely on other means of 24 cutting it back wh'en you don' t need it.
.er fi)s 25 MR. REED: On some concepts too muca of it can ACE-FEDERAL REPORTERS, INC.
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-(-)marysimons 1 take place over a long period of time , and on -some concepts 2 too much of it for 'a short period of time is a problem.
-3 MR. ROSSI: Tha t is true. These plants have 4 somewhat longer.
5 MR. EBERSOLE: Let me ask you question ' about this 6 air system in this context. It has intercoolers on the 7 compressors which water cooled by service water or some 8 kind of water. Suppose I burst a tube in the heat 9 exchangers and I proceed to fill the air system with 10 wa te r . Do I ge t an even worse circumstance?
11 MR. GIITTER: They have dryers in systems that 12 provide ---
-(~h i) s 13 MR. EBERSOLE: Well, that is just a nominal amount 14 of leakage.
15 MR. GIITTER: --- dry air, but I don' t know the 16 system well enough to say whether or not you would have an 17 alarm or what exactly would happen.
18 MR. EBERSOLE: Well, you could block if off.
19 MR. GIITTER: They could isola te it I would think.
20 MR. WYLIE: I assume , and it is not said here ,
21 that all the electrical systems work good and the generator 22 circuit breakers open properly and they have a stable 23 electrical system throughout the transient.
24 MR. GIITTER: That is my understanding.
( ,) 25 (Slide.)
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i 5463 02'02 133 n-( /morysimons 1 The follow-up, and this is from the licensee's 2 LER, the pressurizer heater Group B on Unit I was repaired.
3 The flexible pipe on the instrument air 4 compressors was replaced.
5 The use of. braided , flexible pipe on the 6 instrument air system will be reviewed to determine if 7 other replacement or modifications are necessary to 8 . increase reliability.
9 Check valves are being installed on the discharge 10 of the three reciprocating compressors.
11 Flexible pipe applications in other plant systems 12 in McGuire and at otner Duke Power stations will be
.m
(..-) 13 rev ie we d .
14 MR. EBERSOLE: When you lose the pressurizer 15 heater, you lose the pressure differential from primary to 16 secondary and thus lose the thermal differential for 17 driving heat from the primary to ' the secondary, but it is a 18 slow movement because the pressurizer is an outboarded 19 vessel with lots of insulation on it.
20 How long would it have been before they could not 21 have rejected heat to the secondary because they come to 22 equilibrium with both sides the same tempe ra ture?
23 MR. REED: Je s se , I don' t agree with what you just 24 said.
,/ y .
(_) 25 MR. EBERSOLE: You don' t think you need an ACE-FEDERAL REPORTERS, INC.
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)marysimons1 overpressure ---
2 MR. REED: The fact the pressurizer heater fails, 3 or one banks fails won' t give you ---
4 MR. EBERSOLE: ' Oh, you had another bank on. The re 5 'was only one bank that failed, right?
6 MR. GIITTER: One bank failed and the other one 7 was not in service , but it took about a minute and a half 8 to put that thing in service.
9 MR. REED: And there are some four backup heaters.
10 MR. EBERSOLE: So you had plenty of heater backup.
'll MR. GIITTER: Yes.
12 MR. MICHELSON: What was the cause of failure of
- f( ) 13 the flexible pipe?
14 MR. GIITTER: It was a fatigue failure. As the 15 LER indicated , it was a fatigue failure. It was an 16 accordion type device inside that failed from overload 17 since it couldn' t handle the pressure inside. It was about-18 100 pounds inside.
19 MR. EBERSOLE: There is though evidenceJ here that.
20 there is no integrated system interactive study at this 21 station.
22 MR. GIITTER: I don' t know the answer to that, if 23 they looked at this type of thing in advance or not.
24 MR. ROSSI: You understand that there is an (j' 25 argumen t - here - tha t the safety systems worked, and I think
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(~}arrysimons (j 1 the key is that you have got a non-safety related system 2 that made the event very complicated and it could have
-3 degraded to some thing worse , and that is important. i 4 MR. EBERSOLE: Well, the crux of this, Ernie, is 5 had this matter been anticipated and was it on the 6 documentation that yes, we can tolerate secondary air 7 failure.
8 MR. MICHELSON: Well, I think there are some other 9 plants ---
10 MR. EBERSOLE: Would these consequences.
11 MR. MICHELSON: This plant might have been all 12 right, but as I recollect, some people have put in fire (3
1
/ 13 protection systems using air controls wherein loss of air 14' causes actuation of the sprinkler system which starts to 15 become quite a problem if you had a widespread sprinkler l 16 application.
17 MR. ROSSI: We have a large number of events that 18 are caused by problems in the air systems and, as I say, we
}
19 'are looking at them. And you are absolutely right, I-20 believe there are some of those.
21 MR. MICHELSON: And apparently there is no mention 22 of. anything else happening in this plant at all. .
23 Lpparently even though they lost control there -- and I 24 guess they lost their total air pressure; is that right?
- p)
,_ 25 There are no other events in this plant and no ventilation
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A-)marysimons 1 dampers closed or anything else like that?
2 MR. ROSSI: Do you recall anything else from the 3 LER, Joe, that was pointed out?
4 MR. GIITTER: No. I think all the other systems 5 other than the ones I mentioned operated as required as 6 designed.
'7 MR. MICHELSON: Oh, yes, they can operate as 8 designed. Sprinklers can come on as designed on loss of 9 air pressure , but it is not necessarily a nice thing to 10 have happen to have ' safety significance.
11 MR. EBERSOLE: Let's earmark this event to be 12 brought to the full committee along with a few others we 13 will identify, and at that time you tell us, if you can, if 14 the owner / operator had in fact considered the total loss of 15 air failure and its consequence and concluded in the 16 beginning that his design was all right.
17 MR. GIITTER: Okay.
18 MR. MOELLER: Could you, and I want to support 19 Carl Michelson, could you also tell us what other 20 " failures" occurred or what other valves closed open or 21 wha t-no t tha t we weren' t told about, particularly in ---
22 MR. GIITTER: You are talking about things that 23 would fail as designed during the loss of air such as a 24 sprinkler?
r
(_),/ . 25 MR. MOELLER: Right.
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(-)marysimons 1 MR. MICHELSON: I am pretty sure the sprinklers 2 didn' t come on because that they would have to report.
3 MR. ROSSI: Yes, it is possible that some thing 4 may have occurred that didn' t rise to a significance that 5 aren' t required to be reported in the LER, but I think 6 anything significant would have been in the LER.
7 MR. CLAYTON: I am Brent Clayton from NRR. Jesse, 8 if I can just add, the loss of air ever t is an anticipated 9 event, and McGuire, as all other plants, is required to do 10 a loss-of-air test in their startup program to demonstrate 11 that all their systems do work in a loss-of-air condition.
12 MR. EBERSOLE: And this was done. So this was not
- fs
!)
% 13 an unforeseen event.
14 MR. CLAYTON: No.
15 MR. EBERSOLE: I guass it is just the probable 16 frequency of the event or what might trigger it at least.
17 MR. REED: I am always having to see a loss-of-air 18 event because it seems there is some thing there , some 19 outlying thing that might happen. And I think some of the 20 designers do a pretty good job in looking at the fact that 21 air is not a guaranteed system.
22 MR. MICHELSON: Why didn' t they pick up the 23 sprinkler systems coming on at the finding of loss of air 24 not too long ago during such a te s t? Why didn' t they 25 realize the sprinkler systems would actuate of they raally ACE-FEDERAL REPORTERS, INC.
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_ ) marysimons 1 did a test where they just killed all the air pressure and 2 let down to zero and sat around and see what would happen?
I 3 MR. ROSSI: Do you remember which plant that was?
4 MR. MICHELSON: I don' t recall. It was not too 5 long ago, and it has happened at two dif ferent plants, but 6 over a period of several months because I watch fire 7 protection with particular interest.
8 MR. GIITTER: Those are startup tests on initial 9 startup, and that was a modification or an addition of the 10 fire protection and should have been tested, but may not 11 have been.
12 MR. MICHELSON: Ye s , tha t might be wha t happened g
(_) 13 when they did their modification they didn' t go back and do 14 that te s t . Ye s , that could be.
15 MR. EBERSOLE: I have got the framework of a 16 better question for you to bring an answer to, and that is 17 does the licensee have a committed functional and 18 documented system of accucate study program in being at 19 this time. and I will ask that at all plants.
20 MR. ROSSI: Okay. Le t's go on to the nex t i tem ,
21 which is some problems with residual heat removal pump wear 22 rings at Peach Bottom Unit 3, and this presentation will he 23 given by Tom Johnson from Region 1. Tom.
l 24 MR. JOHNSON: The handout you are getting is not 25 in the package. So it is 3 late-comer.
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'(D t._/mtrysimons 1 Does everybody have that now?
2 (Slide.)
3 My name is Tom Johnson, and I am the Senior 4 Re siden t Inspector at Peach Bottom 2 and 3 which are dual 5 unit boiling water reactors.
6 The -problem concerns a failure of . the residual 7 heat removal pump wear ring. The failure would then lead 8 to possible pump degradation and possible failure. Of 9 course the significance is that you would lose the low-10 pressure coolant injection syctem for a design basis 11 accident and also potential loss of long-term shut-down 12 cooling.
(~T
(_J- 13 MR. EBERSOLEi May I put something in at this 14 time. In the early consideration of these pump systems on 15 GE it was recognized that the single failure criterion had 16 no time sense in it. It was a momentary thing originally 17 derived from the scram system which is a single pulse 18 action, and one had to consider whether these pumps would 19 run for over a period of 90 days or something af ter an 20 accident and whether one could tolerate then failures in 21 time depth.
22 And it was invoked that since there were four 23 pumps you were a lot better off than you were with two 24 because presumably unlike the wonderful one-horse shade ,
e t'y
- l. ,/
s 25 they would fail in sort of an ordered sequence with the I
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\_/merysimons I worst pump failing first.
2 So there is a benefit in having four instead of 3 two and certainly four instead of one, and I guess you are 4 going to tell us there is even a risk if you have got four?
5 MR. JOHNSON: Yes. As we ge t into this we will 6 see that there are four pumps per unit and six of the eight 7 pumps had indications.
8 MR. EBERSOLE: The great uniformity of 9 manufacture.
10 MR. MICHELSON: Just to keep it in perspective, 11 you have to also appreciate that although t. hey have high-12 pressure injection, in loss of containment cooling
(~T s_) 13 function, then you have lost the RHR. They are used to 14 cool the torus, and without the torus cooling , high-15 pressure injection soon will be resolved because it 16 overheats the torus. So these are absolutely essential to 17 core cooling.
18 MR. .EBERSOLE: Well, he says that, Carl.
19 MR. MICHELSON: The inference is that this is a 20 long-te rm core cooling , and it isn' t very long term.
21 MR. EBERSOLE: W~ll, e it is a matter of a few 22 hours2.546296e-4 days <br />0.00611 hours <br />3.637566e-5 weeks <br />8.371e-6 months <br />.
23 MR. JOHNSON: In the design basis accident for 24 Peach Bottom the high-pressure service water pumps, which
,O
(_.), 25 are river cooling water, would come into play here and the ACE-FEDERAL REPORTERS, INC.
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A. /marysimons 1 s ability to cool the torus.
2 MR. MICHELSON: Yes, but let's take a lesser size 3 accident where you can' t ge t those pumps and the pressure 4 is down on those heads and you are in a real bind without 5 RHR.
6 MR. JOHNSON: RHR also has a function to cool the 7 con tainmen t , both the drywell and the torus. That is a 8 true sta tement.
9 .MR. EBERSOLE: Ye s .
10 (Slide.)
11 MR. JOHNSON: These pumps are manufactured by 12 Bingham Company and they are 18 by 24 by 28 which is A
(_) -13 basically the discharge and the suction and volume size ,
14 TDIC. They are centrifugal vertical pumps, single stage 15 and with a tech spec required flow of 10,900 gallons per 16 minute, and they are driven by a 2000 horsepower GE motor.
17 We will get into the sequence of events that 18 occurred over the last few months. I will start off by 19 pointing out that really -- and we have got a picture of a 20 pump up here , a cross-section of the Bingham pump, and the 21 item of interest will be these lower and upper wear rings, 22 which if you see the outline of a pump impeller here ,
23 attached to the pump impeller in this position here as 24 indicated by No. 4 and also on the other side are the lower i
r'
()N 25 wear rings.
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5463 02 02 142 i ,ccrysimons 1 These wear rings are trunk fit and doweled to the 2 pump impeller and provide the wearing surface of the pump 3 so you don't wear out the impe lle r .
4 Also attached and bolted to the pump casing are 5 another se t of wear rings which are not moveable and these 6 two wear ring surfaces provide the wearing surface both in 7 the lower pump 'npeller area and also the upper ---
8 MR. EBERSOLE: I didn' t understand that there was 9 wearing contact. I thougnt these were frae floating and 10 the shaf t clad bearings kept that from accurring. Now are 11 you telling me this thing slaps atound?
12 MR. JOHNSON: There are close tolerances here and n
(/_
13 the design is not to have any contact with the wearing 14 surfaces. But if there is any contact, it would be take up 15 by the contact between the impeller wear ring, which is 16 here and here , and the casing wearing, which is upper 17 casing and lower casing.
18 MR. EBERSOLE: You mean in the new condition there 19 is rubbing contact at this point?
20 MR. JOHNSON: When they put the pump and motor 21 toge ther they check the tolerances so that there is a 22 clearance. I don' t recall wha t the clearat.ce is, and it is 23 designed when they balance the machine that the re is no 24 rubbing. But if there was to be some rubbing, some
(- misalignment, or some bearing problems, then that contact
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143 lhnnrysimons1 would be taken up by the wearing rings. I believe this is 2 a fairly standard design for most major pumps.
3 MR. EBERSOLE: That would be due to deficiencies 4 in the side bearings, right?
5 MR. JOHNSON: That could be from a misalignment of 6 the bearings or misalignment of the shaf t or some vibration 7 in'the machine.
8' MR. EBERSOLE: In any case, you are talking about 9 a few mils?
10 MR. JOHNSON: Yes, sir. It is on the order of a 11 few mils.
12 MR. EBERSOLE: All right. Go ahead.
) 13 MR. JOHNSON: Let me quickly .go through the 14 sequence of events, and this is also in your handout. ,
15 On November 2nd of85 a fire occurred in the Unit 16 3 3C pump. Unit 3 was in a refueling outage that it 17 started in July of '85.
18 The first indication that the operators had, that 19' they noted was a pump trip caused by an electrical fault in 20 the motor, and shortly thereafter, a few minutes after they 21 got a fire detector alarm in the reactor building.
- _ They pursued that. They went into the RHR pump 23 room and noticed that the RHR .3C motor was engulfed in 24 flames.
n
( ,) 25 The pump, like I say, was off and it had tripped.
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5463 03 03 144 llhmrysimons1 They extinguished the fire in a few minutes and proceeded 2 to call in a motor and pump vendor to inspect for damage.
3 The unit was in cold shutdown with fuel loading in 4 progress and the pump was on for some required flow to 5 provide some weld overlays in the RHR in recirc pumping.
6 This is Peach Bottom Unit 3.
7 The vendors came in and they noted significant 8 damage in the motor itself both in the lower bearing and in 9 the motor windings, starter and rotor. They disassembled 10 the pump and they noticed at the pump impeller lower wear 11 ring had come off the impeller. A piece of it had broken 12 out and the rest of it was fused and caught and it was
~
13 l fused to the casing wearing.
I l
14 i So what you are looking at here is the impeller i
sits in here and this is the casing wear ring which is 15 (i 16 l bolted to the casing, and then the pump wear ring, which is Y
17 i normally attached to the impeller, was actually inside. It 18 ' had come off and was left in the casing area.
19 MR. EBERSOLE: Was this a consequential event of 20 the fire and the loss of the bearings or was it a preceding 21 event?
22 HR. JOHNSON: I am going to get into that, but 23 basically the analysis that tha utility did was that 24 through some postulated intergranular stress cracking 25 corrosion, which a piece of this was sent off to the ACE-FEDERAL llEPORTERS, INC.
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l 5463 03 03 145 knnrysimons1 metallurgical lab and an analysis was done that showed that 2 this was some kind of stress corrosion cracking, that a 3 piece actually did break, it did come of f and the 4 centrifugal force sheared the pins, the dowel pins which 5 this thing is attached to the impeller with, and then there 6 was through some period of time, this pump had been on 7 constantly for about two and a half days and run.
8 One of the indications that was reviewed after the 9 event which was not picked up during the event was that the 10 motor bearing temperatures did increase and actually alarm, 11 but they were not picked up by the operators. These were a 12 computer alarm in the control room and the operators just 13 missed picking the thing up. The motor temperature bearing 14 alarm and temperature increased slowly.
15 f MR. MOELLER: Would that be an LER for an operator i
16 to miss observing that?
17 MR. ROSSI: I suspect it would not be, that that 18 alone would not be an LER. It might be reportable as part 19 of another event that rose to the level of an LER where that was a contributing cause.
20 (
21 Is that your feeling, too, Tom?
22 MR. JOHNSON: Yes. This event is being covered in 23 an LER. The licensee has gone back and reviewed this, the 24 fact of why this was picked up. It was reviewed both in an 25 onsite and offsite review committee which I attended, and ACE-FEDERAL. REPORTERS, INC.
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5463-03 03 146 llhanrysimons1 the licensee is taking action to review their computer 2 alarm system, particularly when you have a plant shut- down 3 because you have just a great number of alarms and some 4 sort of prioritization of those alarms and periodic review.
5 MR. EBERSOLE: What about the motor ampere' running 6 load, wasn't it obsc<ved to be higher than normal?
7 MR. JOHNSON: Only when it tripped. It did trip 8 on motor tault, overcurrent.
9 MR. EBERSOLE: But not prior to that time?
10 MR. JOHNSON: Not prior to that, no.
11 MR. WYLIE: When you say they got a motor high
.12 temperature alarm, are you talking about the wind-in G 13 temperature?
(_)
14 MR. JOHNSON: No, the bearing temperature. This 15 motor has a lower guide bearing and an upper thrust 16 bearing.
17 MR. WYLIE: I understand, but did it not overload 18 this system?
19 MR. JOHNSON: No. This piece that broke off 20 actually got twisted sideways causing an upward thrust in 21 the pump and motor unit which was putting an undue pressure 22 on the lower motor guide bearing which was not a thrust 23 bearing causing it to over time to heat up and eventually 24 the bearing failed and ---
iqj 25 MR. WYLIE: But this is the one that had the wind-ACE-FEDERAL REPORTERS, INC.
202 347 3700 Nation *ide Coverage 800 336 4646
5463 03 03 147 knrysimons1 in fire also, or was it the ---
2 MR. JOHNSON: The fire was the oil, primarily the 3 oil. There was some burnt windings. Of course this 4 bearing sits right below the motor windings and rotor.
5 MR. MICHELSON: They didn' t get a bearing 6 temperature alarm from the motor?
7 MR. JOHNSON: You get a computer alarm, but not an 8 enunciator alarm.
9 MR. MICHELSON: I thought the computer alarm was 10 on the bearing temperature of the pump.
11 MR. JOHNSON: No. There is no indication of 12 bearing temperature on the pump, just the motor, the motor 13 guide bearing and motor upper thrust bearinc.
14 ll MR. MICHELSON: What is the material construction i
15 of the wear ring?
16 .
MR. JOHNSON: The wear ring is 410 Martinctic l
17 stainless steel, and I believe we have the hardness. I 18 don' t remember. It was 33 or 39 or something like that.
19 MR. GALLO: The line number was 33 to 39 Rockwell 20 hardness. I think the actual hardness was 43 as found.
21 MR. REED: And this is a BWR that has high oxygen 22 circulating through it and probably an oxygen initiated 23 intorgranular corrosion ---
24 MR. JOHNSON: Yes, sir. The licensee went through 25 an analysis and all the conditions for potential stress ACE-FEDERAL REPORTERS, If C.
l 202-347-37(X) Nationwide Coverage 800 33M6m
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I 5463 03 03 148 llhnerysimons1 cracking and corrosion are here.
{
2 MR. MICHELSON: That is the same wear ring 3 material that Bingham is using on all their other 4 activities?.
5 MR. JOHNSON: I don't know the answer to that. As 6 far as this specific design, this pump and model, the only 7 other unit that has these are the three Browns Ferry units, 8 and they were made aware of the problem through some NRC
.9 and some licenseo contacts.
10 MR. MICHELSON: But the interest might be in the 11 material itself of course and not necessarily just the wear
-12 ring design.
- r. ..
()
x 13 MR. JOHNSON: Correct.
14 MR. WARD: The fact that it was harder material, 15 did that make it more susceptible to stress corrosion 16 cracking?
17 MR. JOHNSON: I am a little bit out of my field
.18 here, but from my understanding, the harder the material, 19 the more susceptible it is to stress cracking and 20 corrosion.
21 MR. EBERSOLE: This is a failure that occurred at 22 a point.in time. It didn' t instantly reveal itself, but it 23 did over an interval of hours I guess, and then it was a 24 unique single failure, wasn't it?
() 25 MR. JOHNSON: It is considered a unique single i
l ACE FEDERAL REPORTERS, INC. l 202 347 3700 Nationside Coverage 804336-6M6 i a--n- _.___=____---._________ _-
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~
5463 03 03 149 kn2rysimons1 failure and, like I say, the licensee brought in General 2 -Electric, the motor vendor, to inspect the damage and 3 brought in the pump vendor from Bingham.
4- MR. EBERSOLE: I have some difficulty seeing that 5 this is a significant safety problem.
6 MR.'ROSSI: Wait a minute. He is not finished 7 yet. We have only talked about the failure of the first 8 pump.
'9 MR. EBERSOLE: Okay. Carry on.
10 MR. JOHNSON: This was the first failure.
11 (Slide.)
12 I am really covering the circumstances here. It
(,~) ; 13 was about two weeks later on November 16th that maintenance 14 was being performed en the 3C pump -- I am sorry, the 3A 15 pump -- the 3C is the one that had the fire. The 3A pump, 16 maintenance was being performed on it to replace the 17 mechanical seal.
-18 In doing that they removed the motor, uncoupled 19 it, lifted the impeller and noted that the wear ring was 20 cracked off the 3A pump. So this is the second failure.
21 Prior'to this time the 3A pump, which was the 22 second failure, was running fine and it was meeting its 23 ' surveillance test performance requirements.
24 And so based on those two failures,.the licensee
( )8 25 decided to go in and inspect'the other two Unit 3 pumps, ACE-FEDERAL REPORTERS, INC. '
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15463 03 03 150 lhaarysimons1. -
which would be the 3B and 3D.
2 Based on inspections of those pumps on November
.3 26th, they noted similar indications. The 3B lower wear 4' ring.was off.
5 MR. EBERSOLE: When you say off, do you mean it is 16 -completely detached?-
7 MR. JOHNSON: It is completely detached. That is 8 this device right here which is the lower wear ring :was
.9 completely off and it was cracked in several places. And
-10 in the case of the 3B, it was also fused to the casing wear 11 ring.
12' MR. MICHELSON: .Now that is a little differenti
~
F-( 13 than your slide indicates. Is that later information? The.
14 slide just says 3D was cracked'and that is all it says 15 about 3B and 3D.
16 MR. ROSSI: Wait, aren't.you just on 3A now?
17 MR. MICHELSON: I am on November 26th on your 18 slide.
19 MR. . JOHNSON: Yes, it is a little different
.20 information. Really it was the second failure. Its lower
- 21. wear ring was off and cracked, and then 3B, the lower wear 22 ring wasloff, it had:a single crack and it was also fused 23 to the casi'ng. 'But-that is a little bit additional 24 'information that is not on this slide.
1
((f 25 MR. MICHELSON: So every one of them has failed.
ACE-FEDERAL REPORTERS, INC.
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- 5463 03 03. 151 lhacrysimons1 MR. JOHNSON: Correct.
2 M]R. EBERSOLE: But when they fail they don't seem 3 . t'o impair operating performance; is this'right?
4: MR.. JOHNSON: In the case of 3C it was an in-5 service ~ failure, and we will see in the case of the other-6 three Unit 3 pumps that it was meeting its flow and 7: pressure and in-service inspection test performance.
.8' MR..MICHELSON: Tell us what flow requirement was 9 being met by the surveillance.
10 MR. JOHNSON: Okay. The surveillance typically 11 ensures'the tech spec minimum of 10,900 gallons per minute, 12 and-then it takes in-service inspection parameter data at:
II 13 11,000 gallons per minute, which would be pressure, current 14 vibration ---
15 MR. MICHELSON: Yes, but when you,do the full flow
-16 test, which is.the one that counts, isn't that a 17 significantly reduced pressure cut the test return line'that 18 is running about 200 pounds?
19 MR. JOHNSON: The typical run-out flow, the max 20 . flow for these pumps is around 11,500 or 12,000 gallons per 21 minute. The test flow is 11,000 gallons per minute, and 22 the tech spec is 10,900. So you are not really operating 23 that much different on the pump as far as differential 24 pressure.
() 25 MR. MICHELSON: Thank you.
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~
t i
. 5463 03 03 152 knarysimons-1 'MR. JOHNSON: So basically the 3D and 3B pumps 2 were-inspected. The13D exhibited a different failure 3 mechanism than the other three Unit 3 pumps, that is being
~4 .the 3A, 3B and 3C. In its case the upper wear ring.was off 5' and cracked. 3D had.an upper wear-ring failure. Once 6 'again, that pump was meeting its test requirements o.
- 7. - meetingiits surveillance test.
8 Of course, Peach Bottom 3 has a sister unit, Peach
- 9. Bottom 2.which.also has four of these RHR pumps. Peach 10 BottomL2 was scheduled for a several week maintenance 11- . outage which began the end of Novemoer. The licensee j 12 decided to go in and check two of the four RHR pumps.on-() 13 Unit 2, those being-the 2A and the 2C.
14 The 2A pump was inspected. Its wear rings were i
15 attached. However, in further visual examination.there was 16 noted service cracks in the lower impeller wear ring. In
-17 other words, .the lower impeller wear ring was- still; on the 18 l impeller, but when they removed it and got it under better.
19 light, you could see basically this stress cracking-
)_ 20 corrosion in its early stages, small surface cracks.
v 21' In the case of 2C, which is the second pump that 22 was inspected on Unit 2, the wear rings were attached and k 23 there was no indication of surface cracks. So 2C basically 24 looked okay. !
l
() 25 In the case of the Unit 3 pumps, they were all l
1 ACE-FEDERAL REPORTERS, INC.
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'5463 03 03 153
'llhm0rysimons1 repaired with replacement impellers and new wear rings.
2 In the case of 2A and 2C, those are the two pumps 3 .that were inspected on Unit 2, they were also repaired with 4 new impellers with new wearing rings.
5 MR. EBLRSOLE: But the same material?
6 MR. JOHNSON: . Correct.
7 MR. EBERSOLE: Assume that the wear rings are not 8 advantageous to reliability or functional performance at 9 least in that present metallurgy.
10 MR. JOHNSON: The pump vendor and the licensee are 11 looking at a replacement material and NRR has been given 12 the lead for evaluating the generic -- or I&E and NRR.
O\
(_j 13 MR. EBERSOLE: The main purpose of these things is 14 to prevent bypass leakage, isn't it?
15 MR. JOHNSON: I think that is one of their 16 functions to prevent bypass leakage. They also provide a 17 wearing surface so that if you do get some misalignment 18 that the contact is not with the pump casing and the-19 impeller but rather the wear rings.
20 MR. EBERSOLE: So if the bearing goes bad, the 21 auxiliary support to the bearing is not within the bearing 22 itself, but rather down on these wear rings because it is 23 cantilevered that far down.
-24 MR. JOHNSON: Correct.
() 25 MR. EBERSOLE: And so they let it strike down ACE-FEDERAL REPORTERS, INC.
202 347 370n Nationwide Coverage 800-336-6M6
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r 5463 03 03 154 llkmarysimons1 there rather than have it wear into the bearing shell some 2 place and stop at a point where you get a hot bearing.
3 They let the wear wear at a place where you can't detect 4 temperature or thrust or anything else until all hell 5 breaks loose.
6 So they are going to look at new wearing rings, 7 but in the meantime they are putting old wearing rings in.
8 MR. JOHNSON: They are putting the old design, but 9 they are brand new wear rings.
10 MR. EBERSOLE: Well isn't it still though fair to 11 say that the likelihood of coincident failures to a bunch 12 of these at one time is not very high? I don't know.
13 MR. MICHELSON: I don't know that you can guess 14 even at that because one of the questions would be how long 15 ! does that 3 -- whatever the pump was that failed, 3C --
16 have other pumps been three or four days at a stretch?
17 MR. JOHNSON: Typically the usage factor for these 18 pumps when the plant is operating is they are tested once a 19 month for maybe 15 minutes as f ar as surveillance. Of 20 course, when you are in cold shutdown these pumps provide 21 shutdown cooling. So they typically can be run for days at 22 a time to provide the decay heat removal.
23 MR. MICHELSON: And they haven't been using 24 selectively 3C for that purpose necessarily? They are l 25 rotating the pumps around?
ACE FEDERAL REPORT ERS, INC.
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- 5463 03 03- 155 kn;rysimons1 MR. JOHNSON: The design of Peach Bottom for 2 shutdown cooling is such that the A and the D pumps are 3 preferred for shutdown cooling because of the piping 4 design.
5 MR. EBERSOLE: Are they the ones therefore that 6 exhibit the first trouble then, the one with the longest 7 hours?
8 MR. MICHELSON: Not necessarily.
9 MR. JOHNSON: No, because the 3C -- the C pump on j 10 Unit 3 was the first failure, and that is not the A or the 11 D.
12 MR. EBERSOLE: Well, the stress corrosion 13 cracking. All right.
14 MR. MICHELSON: The others have failed, but you 15 don't know when.
16 MR. JOHNSON: The only previous failure was on the 17 2A pump in 1982.
18 MR. MICHELSON: No, no. I mean you found the 19 bearings already failed and fused and so forth on at least 20 one or two of the other pumps, but you don't know when that 21 occurred. It just happened that no piece broke out such as 22 in the other pump, 23 MR. JOHNSON: Right. This condition where the 24 wear ring was cracked and off and maybe fused could have
() 25 happened years ago and the pump was still basically turning ACE FEDERAL REPORTERS, INC.
202-347-3700 Nationside Cowcrage 800-336-66:6
I 5463 03 03 156 lhmarysimons1 but no longer with the wear ring attached.
2 MR. EBERSOLE: Tell me, are there vibrating 3 detectors on these pumps?
4 MR. JOHNSON: As part of the surveillance test you 5 take vibration measurements on the pump ---
6 MR. EBERSOLE: But there are no installed ---
7 MR. JOHNSON: There were no installed 8 instrumentation. Part of the licensee's corrective action 9 is to implement a detailed acoustic monitoring system where 10 they are putting acoustic monitors on these pumps, but not 11 as a continual thing, but just to get a signature analysis 12 of the pump and motor when it is run for testing, and that 13 is still early in the experimental stages, but they are 14 't looking at that. But there is no normally installed 15 vibration monitors for these pumps.
16 l MR. EBERSOLE: But apparently they have a l
17 l mechanical vulnerability that may deserve that.
i 18 j MR. JOHNSON: I guess that is a possibility.
l 19 ! MR. EBERSOLE: I guess it is just as important as i
i 20 the noise -- or what do we have on the detectors for loose 21 parts. If you have got a potential here for a failure like 22 ;1 this, it would seem prudent even on a special case to put 23 in some inexpensive noise monitoring, you know, even 24 local. It needn't be audible. It can be put on a scope.
25 MR. JOHNSON: I guess that is a possibility.
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kn=rysimons1 MR. MICHELSON: Well, how would that help you, 2 Jesse?
3 MR. EBERSOLE: Well, you would get a signature and 4 observe the ---
5 MR. MICHELSON: .Then once a part breaks out you 6 know it is broken.
7 MR. EBERSOLE: Yes, but they can detect the 8 incipient contact. I gather this is what happened is that 9 the side bearing fails and it comes into a gradual contact 10 and eventually it gets worse. Certainly the side bearing 11 doesn' t disintegrate at once, or does it? It is a sleeve 12 bearing, isn' t it?
(')
.(j. 13 MR. JOHNSON: Are we talking about the lower pump 14 bearing or the ---
15 MR. EBERSOLE: Yes,,the lower pump bearing.
16 MR. JOHNSON: The lower pump bearing is a sleeve 17 carbon type bearing.
18 MR. EBERSOLE: So it doesn't fail all at once like 19 'a ball bearing. It certainly must have some gradual mode, 20 and the first observation in that failure apparently with 21 the wear. ring and the subsequent damage you described. Is 22 that an order of failure that is logical?
23 MR. JOHNSON: I am not sure it is. In some cases, 24 you know, a failure has not occurred, but the exact failure
() 25 sequence, I don't think it is really understood.
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.5463 03 03 158 knarysimons1 MR. EBERSOLE: In all cases has-the side bearing 2 been found to-have been defective with excessive clearance?
3 MR.. JOHNSON: I believe one case, which was the 4 3D, which had a failure of the upper wear ring, did they i- 5 :actually find'significant damage to the pump journal 6 bearing.
7 MR. EBERSOLE: I don't understand how the pump's
, 8 impeller can move laterally if it has got a good inside
.9 bearing.
10 MR. JOHNSON: You are getting a little bit out of 11 my expertise here. I may have to defer that.
~
12 MR. EBERSOLE: Are there any questions on this Fm
. ' b8 13 now?
14 MR. JOHNSON: There is one additional piece of 15 information that I haven' t gotten to, which is the 2D pump
- 16 exhibited an-in-service failure on December 21st. It was 17 indicated that it was running in shutdown cooling-while 18 Unit 2 was still in its maintenance outage, and it had an 19 overcurrent alarm and tripped, which was investigated.
20 The licensee decided' to inspect that pump knowing 21 what they know about the other pumps, and in 2D they found 22 that its lower wear ring was broken and it was cracked and -
r 23 was also off.
24 So to dato seven of the eight pumps have been 25 inspected. The remaining pump, which is 2B, is being f.
$( )
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202 347 3700 Nationwide Coverag; 800 336-6M6
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< llk.nzrysimons1 tested on an increased frequency weekly rather than monthly 2 and the licensee is, like I said, experimenting with 3 acoustic monitoring.
4 In addition, I&E is preparing an information 5 notice to evaluate this event and get the information out 6 to the rest of the people. The licensee did make an INPO 7 network notification back in November which basically 8 informed people of this situation.
9 MR. EBERSOLE: These plants have been in operation 10 for a long time, 11 MR. JOHNSON: Right. Peach Bottom 2 and 3 have 12 been operating since 1973 and 1974 respectively.
I 13 MR. EBERSOLE: So there is nothing sudden about 14 this.
15 MR. MICHELSON: Are the wear rings replaced 16 periodically or are these originals.
17 MR. JOHNSON: Originals. The only one that was 18 j replaced was the 2A which was replaced back in 1982. The i
19 others, impellers and wear rings, were all original.
20 MR. EBERSOLE: So we don't have a very fast moving 21 phenomena here.
22 j MR. MICHELSON: There were eight failures as I 23 gather.
24 MR. JOHNSON: There were eight pumps. There were 7- '
25 two in-service failures. Actually the pump failed while it ACE. FEDERAL REPORTERS, INC.
l 202 34WW Nationwide Coserage Nn33MM6
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llhacrysimons1 was providing flow.
i l
2 MR. MICHELSON: That was my point. The in-service '
3 failures actually. caused a loss of a pump and the bearings 4 overheated or the windings were heated from excess of 5 current. So there was a total loss of a function in.two of 6 the^ cases.
7 MR. JOHNSON: Correct.
8 MR. ROSSI: One on each unit.
9 MR. JOHNSON: One on each unit, and they were 10 l indications of a potential problem. In the case of the 11 Unit 3 3C pump there were motor bearing temperature
~12 (increases and alarms. In the case of the Unit 2 pump, 20,
() 13 there was a motor overcurrent, high current. indications and 14 overcurrent trips associated with the pump.
15 MR. MICHELSON: So those where there was not an in-16 service failure, there might have been and that is where 17 the speculation comes that if you had tried to run the. !
- 18 ' pumps a few days to accommodate an accident or a few weeks 19 perhaps to accommodate an accident. Then you would have to 20 speculate as to whether the ring failures in that case 21 would cause eventually a loss of all RHR.
22 MR. EBERSOLE: Well the new BWRs only have two 23 . pumps, by the way. They don't have the freedom to have 24 pump failures as the old designs do.
() 25 MR. WYLIE: Do you know what the overcurrent was ace-FEDERAL REPORTERS, INC.
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5463 03 03' 161 knarysimons1 set at that tripped? 'The reason I ask is ---
2 MR. JOHNSON: The normal running current is around 3 230 amps, and I believe the overcurrent, the long-term 4 overcurrent is around 350 to 380, that range. So it is 5 maybe like 100 amps long-term over the normal running 6 current. The design of the overcurrent trip, there is a 7 short-term and there is a long-term trip. The long-term 8 trip is a lower value than the short-term trip.
9 MR. EBERSOLE: Well, isn't the motor loading
'10 through really established by the maximum hydraulic demand
~
11 on the pump which is for the large LOCA condition and so 12 there is a margin, a running margin that you -can' t see when
( ). 13 you are in the normal mode, you know, the recirculating 14 modo and when you are trying to deliver virtually open 15 discharge flow?
16 MR. JOHNSON: In the post-accident condition, 17- which is the low-pressure-coolant injection, that flow is.
18 the same that is tested and it is typically the same flow 19 that is used in shutdown cooling. It is just a different 20 flow path.
21 MR. EBERSOLE: But in the large LOCA it is at a
^
22 run-out condition, isn't it, which is the worst possible 23 load?
4 24 MR. MICHELSON: No, there are orifices to prevent
( )- 25 run-out or your valvo positions prevent run-out.
ACE FEDERAL REPORTERS, INC, 202 347 3700 Nation *ide Co$erage 800-33M486
r 5463 03 03 162 llhmcrysimons1 MR. EBERSOLE: Well, I can see anyway that the 2 normal running load might be masked by a higher load under 3 other conditions.
4 MR. MICHELSON: The peak power input to the motor 5 is not necessarily at the maximum flow condition.
6 MR. EBERSOLE: Any further questions on this one?
7 We have to move on.
8 (No response.)
9 MR. ROSSI: Yes, we have a number of other events.
10 MR. EBERSOLE: We have got three left I believe.
11 MR. ROSSI: Well, I think there are actually four.
12 Let's go on to St. Lucie 1 where they had a m
13 l failure of the vessel internal lifting rig in November.
t MR. EBERSOLE: Now did St. Lucie, while he is 14 f 15 going up there, did it conform to the heavy loads lifting 16 program that is in being at this time?
17 t MR. ROSSI: Steve I think has looked at that.
l 18 l[ MR. EBERSOLE: Would this be a part of the heavy l
19 j load set? Well, he will answer that, too.
I 20 i MR. ROSSI: Yes, it is.
21 MR. LONG: My name is Steve Long. I am with the 22 Events Analysis Branch in I& E. Also today we have Don 23 Sells who is the Project Manager for St. Lucie from NRR and 24 Plorida Power and Light has sont Jack llayes, who is the
- 25 Director of Licensing and Ron Stevens who is our licensing ACE. FEDERAL REPORTERS, INC.
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5463 03 03 163 llkmnrysimons1 contact with St. Lucie, and also Ted Dillard who is the 2 Maintenance Supervisor. So hopefully we can handle any of 3 these questions.
4 (Slide.)
5 The problem was with lifting a heavy load, the 6 upper guide structure, over the reactor vessel on November 7 6th.
8 To got into the actual components we are 9 discussing, the upper guido structure is approximately 50 10 tons. I think that and its lifting rate come out to 64.4 11 tons.
12 It is a fairly massive structure. The support 13 area is the upper flange which rests on the reactor vesnel 14 l plant. The lower portion is the fuel assembly alignment 15 l plato.
i 16 ! (Slide.)
i 17 j The installed position within the reactor core, as 18 ll I said, is supported in the vessel plan. There are some i
i alignment keys toward the top and toward the bottom, and 19 l I
20 then the alignment plate, the fuel alignmort plate comes 21 : into fairly closo proximity to the fuel.
il 22 li (Slide.)
23 The fuoi alignment plato is cut out to fit over 24 , the upper end fitting for each of the fuel assemblies. The 25 plato rests on a spider which is free to move in a vertical I
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i 5463 03 03 164 llhmarysimons1 direction which transmits a downward force on the fuel 2 assemblies through five springs for assembly.
3 (Slide.)
4 Tais structure was then being lifted out of the 5 core during an outage. The lift rig used to lift it is 6 fairly large. Let me move this up so you can see the part 7 I am talking about.
8 The lift rig is guided down to the structure with 9 two bushings that fit over two of the reactor vessel guide 10 pins. It then extends up out of the water so that 11 operators can connect the rig down to the upper guide 12 structure.
13 It is attached with three bolts. The bolts are l 14 fairly short and the heads rest on surfaces down at the
- I 15! bottom of these hollow columns.
16 { The bolts are attached with torque tools that run 17 up the column. The requirement I believe is 60-foot support.
10 l 19 ! The problem occurred in that one of these three 20 bolts was apparently not f ully engaged when the rig was 21 attached to the upper guido structure.
P1R. EBERSOLE: What you are telling me in the very 22lI 23 beginning is that this rig is not designed with a single 24 failure criteria.
! ) 25 f1R. LONG: I don't believe they claimed that it Aci!-Frint!RAL Rl!PORTiiRS, INC.
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'5463 03 03 165 llhmerysimons1 was in their filing.
2 MR. EBERSOLE: So then I must say I must be 3 prepared to drop this thing at any. time because the bolt-4 might break. Can I do that?
5 MR. LONG: You will see that two bolts will hold 6 it. On the other hand, there is a common mode potential 7 here in that they could have done the same thing with one 8 of the other bolts perhaps.
9 MR. EBERSOLE: Well, that is being consistent.
10 MR. LONG: The problem was first noticed when the
) 11 rig and the upper guide structure had been raised about 12 eight feet. At this point the two reactor vessel guide
() 13 pins started to tapper down.
14 The assumption here I. believe is that lateral 15 forces that were first held by these two guide pins were 16 allowed to occur and this one bolt was apparently attached 17 by about a half of a turn on one thread, and at that point 18 it became disengaged and there was a perceptible cocking of 19 the guide structure so that the guido structure raised at 20 the point of separation by about six inches and the 21 internals were allowed to sag by about six inches. So you 22 had 12 to 15 inches of separation.
l 23 MR. EBERSOLE: So it was being observed and they i 24 saw this and stopped it.
$ () 25 MR. LONG: Yes.
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5463 03.03 166 lhmarysimons1 MR. EBERSOLE: Suppose they hadn't seen it. What 2 would have happened?
3 MR. REED: I am a little surprised here. I have 4 seen a number or rigs attached and lif ting up the barrels 5 of things. I am a little surprised to hear that the 6 maintenance routine, that'there was not a counting system 7 for the number of turns. When you push these down you are 8 pushing against a spring.and then you get engaged. And how 9 you count the turns. Thic is a standard maintenance 10 activity. You count turns and see if you get eight turns 11 when you bottom out. If you don' t get 'eight turns, .then 12 you have got thread doweling or some other kind of lock-l ) 13 up. If you don' t get your eight turns, you don' t lif t.
14 Now'the backup to that is you have level 15 indicators on the rig which tells you at the moment of lift-16 off whether or not you have a level lift. Now this lift 17 couldn't have been level at the moment of lift-off.
18 MR. LONG: You are getting a little bit ahead, but 19 I will try to address both of those.
20 Let me wait for the question of what would happen 21 if you dropped it. ,
22 MR. EBERSOLE: Okay, sure.
l 23 MR. LONG: The misalignment during the initial l l
24 part of the' lift would have been a few inches of the bolt
() 25 length that could have been pulled down until the bolt head ACE. FEDERAL REPORTERS, INC.
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5463 03 03 167 llknarysimons1 was actually resting along the bearing surface of the 2 bottom of the lift rig.
3 I have been told, but haven't seen it actually 4 written down that probably that thread was able to carry a 5 good portion of that load during the initial part of the I
6' lift until it was allowed to essentially unhook or some 7 lateral motion was possible. These are two-inch diameter 8 bolts.
9 The scenario now was that they got it raised by 10 eight feet and they got a perceptible cocking. They 11 I stopped the lift and they immediately attempted to relower 12 this structure bac.s to its installed position and they got i
13 an indication on the load cells that there was binding, 14 that is the load was decreasing.
15 So they stopped the thing in place about eight 16 feet over the core and took some steps to -- they used 17 additional precautions here. They installed some transits to make sure that the load or rig was not still shifting.
18 l 19 They declared an unusual event and notified the Operations 20 Center in Bethesda.
21 At that point it then became a problem of trying 22 to do some underwater inspection to see what had happened 23 and then try to design a way of getting the thing away from i
24 the reactor core.
I I 25 Sort of the post-mortem of what happened here ACE-FEDERAL REponTEas, INC.
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^5463 03 03 168 llhm2rysimons1- involves the fact that they had a procedure for counting 2 these turns that came with the Combustion Engineering )
3 procedures for installing the rig, and that particular step 4 was apparently omitted during the revision of the ;
.5 procedures sometime after startup by the licensee. It was
'6 an oversight. It wasn't intended to omit that step.
~
7 The licensee's ' people can maybe speak to this a 8 .little bit better, but I understand they had had some 9 problem in the past with actually getting proper alignment 10 between the holes that are in the guide structure and the 11 holes that are holding the bolts.
12 So that-it is a matter.of.trying to keep the guide
() 13 structure up a little bit and get the bolts properly -
14 engaged, turn them a little bit, lower the structure, turn 15 them a little bit more and lower the structure. So'it is 16 possible that they were turning it and lowering it and in 17 such a way they have gotten the right number of turns. I 18 don't know. They didn't speak to that,.but they may have 19 not been actually turning the threads into the holes with 20 those turns.
21 MR. REED: I know there is a bit of a juggling act ;
22 -and sometimes you set these down and you get two to go all 23 the way down and you have got to release those two and try 24 your juggling again to get the thing on the circle so the
() 25 bolts coming down line up with'the holes and thread all the L
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'5463 03 03 169 llhm2rysimons'I way in. But it would seem to me that capital attention 2 that should be here and you would never'have a single turn 3 engagement. I don't understand it.
4 MR. LONG: Well, I am not sure that I can answer.
5 MR. EBERSOLE: I guess what I am looking for is
. 6 not really the fine structure details of this but the 7 generic overall aspects of it. Do we have a weakness in 8 the design or in the operation or both and what are we 9 going to do to converge on the safety aspects of this 10 incident?
11 MR. LONG: Okay. I think there was. clearly a 12 weakness in procedure. The technique that the licensee
( )- 13 used to reinstall this also gave what I guess is my 14 personal opinion a little bit better approach to the action -7 15 mechanism, although they haven't decided that is the way 16 they want to proceed in the future, at-least not as far as
- 17 I know yet.
18 Let me try to finish it up fairly quickly-as to 19 what happened.
20 I guess what I want to do is quickly say they 21 designed and installed a secondary lif ting device that 22 essentially provided a mechanism for hooking "J" hooks with 23 keepers around the upper flange. There were three of those 24 cables that ran up parallel to the columns that I showed 1( ) . 25 .you on the regular lifting rig. They used a jacking bar !
e l
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5463 03 03 1 170 llhmarysimons1 system to support it at the top and the upper guide 2 structure level. And then they used this to move it into 3 its normal parking position in the refueling pool.
4 Following that they did a fair amount of 5 inspection to try to determine what had really caused the 6 problem, and this is where they really got a handle that it 7 was only half of a thread that was probably engaged.
8 Previously they thought it was about three threads based on 9 an underwater camera inspection. They had apparently been 10 misled by the underwater appearances at least on the 11 threads.
12 At any rate, the licensee used a slightly m
) 13 ; dif ferent approach for mounting the rig to the structure i
for the reinstallation.
14 l I
15 (Slide.)
i 16 l In the reinstallation they replaced the short i
17 bolts with the long torquing tools with long bolts, that is 18 a bolt that has the same penetration into the threaded 19 sectico at the bottom, but the bolt shaft essentially runs 20 up so that head bears on the surface at the top which again 21 will in my opinion give you a better visual indication that 22 the bolt is down on the bearing surface prior to the lift.
23 MR. REED: The rigs I am familiar with are built 24 that way. I didn't realize this was a short bolt down 25 there.
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5463 03 03 171 llknrysimons1 MR. LONG: So the question you had asked about a 2 perceptible tilt, given four inches across the diameter of 3 the head, and I am not sure you can see that very readily 4 until you have really separated the bolt, but you could see 5 something at the top.
6 (Slide.)
7 The licensee has now reinstalled the structure.
8 They have gone through and review their other lif ts and 9 reviewed the procedure for this lift to make sure that the 10 thread engagement step is properly backing the procedure 11 and IE is preparing an information notice.
12 Now in terms of the consequences and what happens 13 if you actually drop this thing oack into its installed i
position, there was an unresolved safety issue which began 14 l i
15 l addressing that. It is 836.
16 MR. EBERSOLE: I thought that had been pretty well f
17 concluded, hadn't it?
MR. LONG: It has been resolved, but the analysis 18 l i
19 has been terminated. There was a Phase II analysis under 20 that issue that was to predict the consequences of various 21 drops, and part of the Phase II analyses were done, but 22 they were not completed because the NRC terminated that 23 part of the study.
24 MR. EBERSOLE: You mean the 'RC prematurely I 25 terminated this critical part of the question, am I going ace-I liorinat. IIEPORTEns INC.
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5463 03 03 172 kn:rysimons1 to drop it. If the answer is yes, what happens. If I am 2 not, okay. I have to design to certain criteria. Was that 3 never wrapped up?
4 MR. LONG: It was wrapped up prior to my joining 5 the Commission. So I am not quite sure what allowed them 6 to finally say it was resolved satisfactorily, but they 7 apparently decided that the drops that they had seen 8 analyzed were of low enough consequence to allow them to 9 wrap it up.
10 MR. EBERSOLE: Did this include dropping such rigs 11 on top of a BWR which has collar o s on the rods which 12 ' will drop out and result in an excursion?
13 l M R. LONG: That I did not look at, Let me try to i
14 [ tell you what was the closest analysis that I could find 15 , that was done for a CE plant that approximates what we are 16 talking about here. That was done for Waterford and it was i
17 not actually a drop of the upper guide structure, It was a 18 drop of the reactor vessel head that tilted in such a way 19 that it could get down below the flange level and 20 physically impact the upper guide structure.
21 The calculation was done for total drop ic t ,'.t of a
22 l 41 feet, assuming 16 feet in the air and 25 feet J r .
ter.
I 23 And the calculation was that after impact with th' igror 24 guido structure there would be a response velocity in the m
i 25 upper guide structure of 28 feet per second.
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5463 03 03 173 lknrrysimons 1 Now this assumes that the upper guide structure is 2 already properly aligned with its keyways and the upper end 3 fittings and so on.
4 So if you take a look at the St. Lucie situation, 5 you have got a couple of differences. First of all, the 6 response velocity would not be as great because if it was 7 dropped in air instead of water it would only be 23 feet 8 per second. Secondly, it is not properly aligned during 9 the drop. So you have got a question of with the 10 misalignment perhaps it would slow the drop or actually 11 prevent it from getting into its installed position at all.
12 MR. EBERSOLE: Let me try to focus on a conclusion 13 , of this as I see it and then I am willing to be shot out of i
the saddle. You are telling me you have this particular 14 {i 15 1 incident. Subsequent to it you determined that it wouldn't 16 have hurt much if you had dropped it anyway, but you hadn't 17 done it prior to that time and you didn't know in advance 18 what would have happened.
I And then you tell me that the unresolved safety 19 l 20 issue of handling heavy loads was abruptly terminated 21 before one had done an exhaustive study to see what the l
22 consequences were of dropping loads.
23 That leaves me hanging.
24 MR. ROSSI: I think we need to look and see the 25 reasons and the status of the unresolved safety issue ACE-FEDERAL REPORTERS, INC.
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5463 03 03 174 lhmerysimons1 because we really-aren't prepared to talk about that today.
2 MR. EBERSOLE: The only thing I can see out of 3 -this to take to the full committee is just that aspect of 4 the unresolved safety issue. Where do we stand with this 5 as a trigger to identify a need to have a look? Where do 6 we stand. Have we homed in on his heavy load drops, not 7 with this as a specific problem, but just as a triggering 8 event to have a look and see where wo stand most with 9 concern, at least on my part, that we may have abandoned 10 the effort before we have found the consequential effects 11 of dropping loads.
12 MR. MICHELSON: Boiling water reactors are in a
) 13 little bit worse configuration. Separator assembles, for 14 instance, are supported by core support plugs inside the 15 core barrels, and you might want to make a little 16 calculation on what it takes to sheer those plugs off of a 17 six or seven ton separator assembly.
18 MR. EBERSOLE: I see no point in pursuing the 19 details of this particular event, but I do soo a need to 20 pursue ---
21 MR. MICHELSON: But of courso there is another 22 problem though I have besides this possibility. There is 23 still the requirement to handio shield plugs over the open 24 coro during the process of moving this assembly, and shield
() 25 plus fall in a different way. They fall straight down like ace FnonRAL REPORTERS, INC.
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- 5463 03 03 175 llhnrysimons1 arrows and there is nothing to retard them except the 2 velocity and viscosity of the water. And I can't imagine 3 if you looked at a shield plug dropped in a core that you 4 would say it is a no, never mind. I don't know. I have 5 not had the occasion to look at this unresolved safety 6 issue.
7 MR. EBERSOLE: Well, the interesting part of that 8 configuration that he is talking about is you almost 9 certainly will knock a buach of rods out and you will havo 10 a low-poworod excursion which may kill people from flesh 11 exposure. That is all.
12 MR. MICHELSON: And it is uncontained of courso.
A
(,) 13 There is no containment vossol around the boiler when it is 14 in refueling. It is just a shoot metal building.
15 M R. EBERSOLE: So I think just the generic aspects 16 of this, Ernie, with this being identified as a trigger 17 event would be something to comment to the full committoo 18 on.
19 MR. ROSSI: Okay. We will take a look at its 20 relationship to the unrosolved safety issuo.
21 MR. EBERSOLE: That is all.
22 MR. MICHELSON: It shows that no mattor how 23 careful we have boon, we can still mako mistakes lifting 24 those assemblios and it would be very important to know
() 25 what the consequences are.
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l 5463 03.03 176 llkmarysimons'1 MR. EBERSOLE: You have to say I can drop it or I 2 can' t drop it.
3 MR. LONG: If I can show you this crux of the 4 problem with the' analysis.
5 (Slide.)
- 6. The analysis that was done for Waterford, which 7 would be a worst drop than what we have here in the sense 8 of force was that there would be essentially no problem for 9 the fuel. It could be reused without any significant 10 increase in leakage. So we are not going to be releasing 11 gamma - activity or doing any of the other dire events.
12 However, that analysis assumes that you get-this
'( )
~
11 3 proper alignment in here. Now it gets down to an actual 14 geometric problem of whether or.not this piece could hit 15 that end post and if it did. so how much problem that would , '
n 16 be. And that is a little bit difficult to just quickly do.,
.17 MR. EBERSOLE:. Yes. .These analyses of drops, of 18 course you have to watch them-because sometimes they will' 19 invoke that it will fall square and actually before it
-20' contacts the bottom it.has a hydraulic brake. In. fact, in 21 .real life'it will come in on the bias.
22 I remember the cask drops on the boilersg Iff it
. 23 comes down cornering, it will go right through the fuel 24 pool. There are interesting ways to try to avoid worst
( )l 25 . consequences:in the analyses which are not easy to detect.
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5463 03 03 177 lknorysimons1 MR. ROSSI: We will get back to you with more 2 information on the unresolved safety issue.
3 Let's go on now to an event on Susquehanna Units 1 4 and 2 where a partial loss of offsite power caused a 5 control systems malfunction and a trip of both units. This 6 will be discussed by Mary Joe Campagnone from the Office of 7 Nuclear Reactor Regulation.
8 MS. CAMPAGNONE: Good afternoon. I am Mary Joe 9 Campagnone. I am a Project Manager for Susquehanna, 10 (Slide.)
11 On December 2nd Susquehanna experienced a loss of 12 their T-lll transformer, which is this transformer right 13 here. It normally powers the C channel for both Units 1 14 and 2.
15 When they lost the transformer due to an internal 16 fault, the loads were automatically picked up by the 211 17 transformer, which is over here, which picked up the C 18 loads for both units. That transformer normally carries
'" 19 the B loads, the B channel for both units,~but it can also 20 power the C.
21 The loss of the AC power interrupted power to 22 certain control panels before the loads were picked up.
23 There are certain panels, instrument control panels that 24 are at Susquehanna that the utilities cannot tolerate a 25 momentary interruption of power.
1 ACE FEDER AL REPORTERS, INC.
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5463 03 03 178 knerysimons1 When they did interrupt the power, they got j 2- erroneous signals to their feedwater controllers. They 3 know that they have this problem. So the feedwater 4 : controllers were designed to lock up causing the three 5 variable speed feedwater pumps to fail as is.
6 In this event the operators have three-lights in 7 the control room that tell them that they have an 8 interruption in power and they can manually reset the-9 switches so that they can get manual control. of the 10 feedwater controllers.
11 For Unit 1 the operators did not realize this.
12 First of all, two out of the three indicating lights'in the
/~
(_)r 13 control room failed. Even though one was working, they 14 failed to reset the switches and take manual control. They 15 got a steam feed mismatch and they went out on high reactor
.16 water' level.
17 It took about four minutes for Unit one to go out.
18 In Unit 2 the operators realized they had made a 19 mistake. They reset the switches. They would have been 20 all right, but there was a logic error in their A feedwater 21 pump. So when they reset those switches, the A feedwater 22 pump on Unit 2 wound down to zero. Even though they had 23 manual control for the A and B feedwater pumps, they could 24 not make up the water, and the level had already dropped to
() 25 level three and the reactor scrammed on low water level.
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5463 03 03' 179 lhacrysimons1. The level decreased to minus 31.5 inches, RCIC
'2 auto initiated, the MSIV's closed. They close 3' automatically. The set point is only at minus 38 inches, 4L and at Susquehanna the set point is slightly higher, but 5 still within the tolerance. So that is why the MSIV's 6 . closed and the HPCT was manually initiated.
7 The licensee before they even went back up in 8 ' power after this event modified the load lines so that the 9 feedwater instrumentation is powered from their vital AC 10 and they will not have a problem.
11 The licensee has done this. He_has been requested
-12 to identify other instrumentation. They have identified
) 13 'other instrumentation and that instrumentation, most of it 14 is, one, normally not_ running during normal plant operation 15 and, two, can be reset in a period of time that won't 16 impact plant' operations.
17 MR. EBERSOLE: Well,_this is just really the
-18 finding of a challenge which shouldn't have existed to 19 normal power generation. It was not a real safety problem, 20 was it, except a challenge?
21 MS. CAMPAGNONE: Well,.I guess the problem was 22 .that No. 1, Susquehanna knew they had this problem with the P
23 panels and they knew that the feedwater control was on.
24- They had set up the system and they thought they could n
. (_) .25 recover from it without scramming two units. They couldn't
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5463 03 03 180 hmarysimons1 put in the modification that they had planned to put in 2 anyway.
3 MR. EBERSOLE: And really where they missed it was 4 in the inability of the operators to respond.
5 MS. CAMPAGNONE: Right. But I really have to say 6 though that even if the operators responded perfectly on 7 both of them, I don't think they would have had enough time 8 to recover two units.
9 MR. EBERSOLE: They had a logic failure as well.
10 MS. CAMPAGNONE: Right.
11 MR. EBERSOLE: So this was an undesired and 12 unexpected consequence from a transformer failure.
() 13 MS. CAMPAGNONE: Not unexpected though.
14 (Laughter.)
15 MR. EBERSOLE: Right. .You just always anticipate 16 a transformer failure.
17 'but. ROSSI: I.was also struck by tha fact that it.
18 affected both units.
19 MR. EBERSOLE: Oh, yes.
20 MR. ROSSI: I mean that raised a significance as
'21 opposed to ---
22 MR. EBERSOLE: I can tell you a story where a 23 domestic water switch shut down 10 units.
24 MS. CAMPAGNONE: Okay. Is that.it?
() 25 MR. EBERSOLE: That's it. Thank you.
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5463 03 03 181 J
.llhamrysimons1 I'see no questions for this. l 2 MR. ROSSI: If we have' time at the end, and I 3 don't know whether we are going to, we do have somebody 4 here who was here and I didn't realize on the heavy loads 5 issue who can address your questions.
6 Do you want to do it right now?
'7 MR. EBERSOLE: Our schedule is 1:15.
8 MR. ROSSI: Oh, okay. We have got two more events 9 and that.
10 MR.'EBERSOLE: Sure, we are not out of line, 11 unless somebody has got some conflicts..
12 MR. ROSSI: Why don't we let Bob Neighbors answer
.n.
+
(_) 13 your. questions.
14 MR. EBERSOLE: Sure. Go~ ahead.
15 MR. NEIGHBORS: I am Don Neighbors, Project 16 Manager. 'I was the lead Project Manager for the Generic 17 Issues, Heavy Loads. _;
- 18 We have' resolved-that. issue as you were 19- discussing. Back in June -- well, actually we had broken "20 .the heavy loads into two phases, both Phase I and Phase II.
- 21. . Phase II dealt with basically dealing with single 22 failure cranes and.the consequences-of accidents if you did 23 not have those.
24 Phase I dealt with more of the things that the
- 25. licensee could do around the plant, such aus making load ACE-FEDERAL REPORTERS, INC.
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l 5463:03f03 182 kacrysimons1- passes, training his employees, doing in-service
=-
2 inspections on1his lif ting devices and making sure they 3 were in good shape and tested properly.
4 In June of 1985 we had' closed out the Phase'II 5 part of.that issue based on the fact that we had done 6 almost all of the review of the Phase I of looking at all 7 of the analyses of the plant where they had taken measures 8 .to make sure that they-had-their load handling equipment in 9 good shape, the crews trained and the equipment inspected.
i 10 And based on that, plus the fact that we did an in-11 depth review of some.20 plants in the Phase I analyses, we 12 went ahead and felt comfortable enough and competent enough
) .- 13 that ~ there were no major issues out there and based on cost -
[ 14 benefit analysis, we decided to go ahead and close the 1
15 Phase II issue.
i
- - 16 And subsequent.to'that we eventually closed out 17 the Phase I because at that time there were only two or_ ,
18 three plants in the Phase II category.to be closed out.
19 '
~
! 1MR. EBERSOLE: What did you do with the issue of 20 50 ton concrete block over the BWR core? >
21 LMR. NEIGHBORS: I can't' answer that specifically.
22 MR.:EBERSOLE: Why don't we answer that as a case 23 in point.
24 MR. NEIGHBORS: For that device I cannot answer 7 -
25- that specifically, but'this is the type of thing that I ACE FEDERAL REPORTERS, INC.
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5463 03 03 183 llhmorysimons1 think we relied on the licensee's inspection, the 2 inspections of his tools and equipment ---
3 MR. EBERSOLE: Well, this gets into the design 4 though of the tool, the crane proper, the cabling.
5 MR. MICHELSON: And the design of the f uel plug, 6 too, if the cable breaks.
7 MR. EBERSOLE: The lifting cables, you know, and 8 the make up of the hitches. It is not simple.
9 And also why don't we in the course of talking 10 about this briefly to the full committee tell them how we 11 have rounded out or closed out this investigation about --
12 oh, I will just pull one -- about the fuel cask for the j 13 boilers with the upstairs fuel storage pool, the strength 14 of the floor of the pool, et cetera.
15 Early on, like 10, 12 or 15 years ago it was found 16 that the cask would penetrate the pool floor leaving an 17 embarrassing set of exposed fuel which had been used to 18 shine into the sky without water cover.
19 MR. NEIGHBORS: I can't address that myself 20 personally, but we can ---
21 MR. EBERSOLE: If you can' t address that and you 22 were the Project Manager, I don't think you have pursued it 23 in enough detail.
24 MR. NEIGHBORS: We can have someone from the
~
25 technical staff to address those issues.
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i 5463 03 03 184 anrysimons 1 MR. EBERSOLE: Why don't we do that.
2 -MR. ROSSI: Okay. We will on Thursday come with 3 somebody to address just the unresolved safety issue. We ,
4 are not going to go back through the event that we talked 5 about, but whoever addresses the unresolved safety issue 6 could ---
- 7. MR. EBERSOLE: We will put it that way. We have a 8 triggering interest.
9 MR. ROSSI: Okay, fine.
10 MR. EBERSOLE: Let's go on.
11 MR. ROSSI: Next we have a discussion of some loss 12 of offsite power events. Rabi Singh from the Office of
("
+
A_j) 13 Inspection and Enforcement will make this presentation.
14 MR. SINGH: I am Rabi Singh from I&E. I will be 15 talking about three loss of of fsite power events.
16 '(Slide.)
17 The first one is on Indian Point 2. I would just 18 like to briefly describe their system.
19 The primary source of offsite power is from the 20 switchyard. It comes through the aux transformer here.
21 The secondary offsite power source is from the gas 22 turbines that comes down here.
23 Normally plant operation falls generally this 24 way. There are a whole bunch of buses here, one through
~( ) 25 six, and they all tie together.
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e 5463 03 03 185 llknarysimons.1 On the day of the event, on December 12th, the 2 plant was in hot shutdown condition. Some technicians were 3~ doing some relay checking in the control rooin. During that 4 process they bumped into a panel. There was some relay 5' chatter and these two breakers opened up, ST-5 and ST-6.
6 So they had a loss of offsite power.
7 This shows the main valve. However, it requires 8 manual operation of these two breakers to get the 9 alternate, or the secondary outside power on. The licensee 10 decided not to do that. The diesels had picked up all the 11 loads as necessary.
12 The reactor coolant pumps were lost, they entered
() 13 natural circulation and offsite power was restored within 14 15 to 20 minutes.
15 That is event No. 1.
16 MR. MICHELSON: Were those seismically qualified 17 relays?
18 MR. SINGH: I don't have the answer to that.
19 MR. MICHELSON: It would be kind of interesting to 20 see what the seismic qualification is.
21 MR. ROSSI: Well, that is probably not a part of 22 the safety related portion. I would guess that it is not 23 because it is tied in with the breakers that are only 24 associated with offsite power.
() 25 MR. EBERSOLE: Well, Ernie, let me postulate that ACE-FEDERAL REPORTERS, INC.
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5463 03 03 186 lknnrysimons1 the relays malfunction in this chatter mode. And while the 2 diesels are coming on I guess you can invoke the fact that 3 an earthquake won't last 10 seconds or something.
4 But, anyway, they reconnect the grid to the 5 diesels and collapse the diesels. I mean in short I am 6 trying to validate the disconnecting function and 7 guaranteeing that it maintains that condition. Can I do 8 that, Ernie?
9 MR. ROSSI: I would suspect that the sequence that 10 you describe has not been looked at. That would be what I 11 suspect.
12 MR. EBERSOLE: Well, you don' t want to reconnect.
I 13 MR. ROSSI: The qualification of the relays 14 associated with offsite power to reconnect after you 15 disconnect it, I would suspect that that is not worked in.
I 16 MR. EDERSOLE: Well, isn't it just as important to 17 reject the loads you don't want as it is to get the sources 18 of energy where you need it?
19 MR. ROSSI: If that could interfere with the 20 onsite power, I would agree with you.
21 MR. EBERSOLE: I don't want to reconnect --
22 MR. WYLIE: You are saying that you have still got 23 g these relays chattering?
24 MR. EBERSOLE: These relays are chattering and I
25 they will ---
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5463 03 03 187 llhmarysimons1 MR. WYLIE: And the light relays such as sync 2 check relays.
3 MR. EBERSOLE: Yes.
4 MR. WYLIE: In this case here if the diesels came 5 on, of course you have opened the breakers to the normal 6 power system here when the diesels came on and it would 7 take a manual action to close it, but there are sync relays 8 in there.
9 What you are saying is what about the sync relays.
10 MR. EBERSOLE: Any relays that reconnect the 11 undesired the loads.
12 MR. ROSSI: Well, probably the portion that i 13 disconnects you from loads and so forth would disconnect 14 you from offsite power. That maybe part of the safety 15 related system. I don' t know.
16 MR. EBERSOLE: It should be routinely qualified I 17 think.
18 MR. SINGH: I believe these relays would chatter 19 where anything that goes onsite is involved.
20 MR. ROSSI: Yes, but his problem is that even 21 though they don't have any direct problem with onsite 22 power, they can reconnect the offsite power if they are not 23 part of the safety related system. That is what his 24 problem is.
25 MR. EBERSOLE: Right. Sure. You don't want to ACE FEDERAL REPORTERS, INC.
202-347-3700 Nationwide Coverage 800-336-6M6
I e-c l5463 03 03'. 188 O arysimons l'- --reconnect the loads you can't carry.
-2 MR..MICHELSON: It is a systems interaction 3 problem.
4 . MR. EBERSOLE: It is a tightly integral systems 5 interaction. I mean it is very simple. You just can't 6 reconnect the load you wanted to' ditch.
7 Well,-other than that ---
8 MR. ROSSI: We wanted to give you a flavor of the 9 kind of events. All of these occurred I believe at plants 10 that were shut down.- Some of them could have occurred with 11 the plant running and some of them maybe not.
, 12 . MR. : MICHELSON: Have you given some consideration
)- 13 to the fact that these apparently are susceptible to
- 14 . vibration, these relays, and there are other relays in this-15 plant also susceptible to vibration in the non-safety area, I
-16 and have you thought about whdt an earthquake would.do if a 17 number of these were ~ chattering all at the same time?-
18 MR..ROSSI: We did not extrapolate this particular 19 event to go back and do anything. We are describing it 20 because it is a problem that involves the loss of offsite 21 . power for a particular reason and to give you a flavor for 22 the kinds of things we'really see on plants.
23 But as far as trying to go back and correct 24 various problems, this one I don't think received any (f- 25 particular follow-on of that sort.
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m 5463 03 03 -189 knarysimons.1 Now you might also recognize the fact, I would 2 assume, that the probability of bumping cabinets and so ;
3 forth with the plant running is considerably less with it 4 shutdown because you are not doing the kind of work ---
5 MR. MICHELSON: I wasn't raising an issue of that
.- 6 sort at all, but the earthquake of course bumps ---
7 MR. ROSSI: We did not do any follow-on. The 8 events are here to tell you the kind of things that are i 9 really happening and how they coped with them.
10 MR. EBERSOLE: Why don't we let this be again a 11 kind of a triggering incident to review the question. We 12 are very zealous about guaranteeing the qualification of
(). 13 relays and circuit breakers and other things to close on 14 needed loads.
15 Are we equally zealous in clearing and locking out 16 loads which our onsite plants can't carry? I make that in 17 that very broad context, and you might have a word or two 18 again just commenting on this as being an event that raises 19 this interesting question.
20 Other than that, I don't see that the individual 21 aspects of this event are unusual or significant.
22 MR. ROSSI: We have two more events that involve 23 losses of offsite power and then we have Alan Rubin here 24 who is going to say a few words about the status of USI
() 25 A-44.
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5463 03 03 190 knarysimons1 So go ahead, Rabi.
2 '(Slide.) ,
3 MR. SINGH: This is a partial schematic of 4 Waterford Unit 3 switchyard.
5 'Just briefly going over, this is Waterford Unit 3 6 here, Waterford Unit I here and Waterford Unit 2 here. You 7 have two startup transformers that spread from these lines.
8 On December 12th, af ter the lightening struck, 9 Phase B of this line, which is connected between another 10 switchyard., Little Gypsy 1 and the Waterford switchyard, 11 the breakers here opened up to clear the fault. No problem 12 so far. >
l
) 13 But at the same time apparently Unit I which was 14 operating had a sudden pressure relay which tripped this 15 unit.
d 16 A little later these breakers auto closed. So 17 this line went back in service. A few minutes later a 18 dispatcher tried to close this breaker here, and this 19 breaker apparently had a failed bushing.
20 Because of that fault here, all these breakers 21 ultimately cleared the fault. At the same time, these two 22 breakers here opened up, which killed this line, 23 transformer B.
24 MR. MICHELSON: Why did they open up?
() 25 MR. SINGH: Later on the investigation by the l
l l
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5463 03 03 191 llhmarysimons1 licensee showed that they have conversion relay which 2 actuated because of the plant condition and the relay 3 setting. The relay setting was apparently for Unit 3 to 4 operate. I do not have all the details on that, but I can 5 tell you that the setting on the conversion relay was not 6 proper for the plant condition. In any event, this was 7 lost.
8 A few minutes later this breaker was closed again 9 by the dispatcher, and this time it killed this line over 10 here. So they had a complete loss of offsite power. It is 11 my understanding the dispatcher was following the written 12 procedures.
l 13 Now a couple of other items here. When all this y
14 f was going on, they also lost this line which is connected 15 to another switchyard.
16 Another which, which I haven't shown, which is a 17 primary KV line connected with this switchyard and also was lost.
18 l 19 Now they restored the offsite power in about 40 20 minutes and shutdown was lost for approximately five 21 minutes.
22 MR. MICHELSON: Are there explanations for all 23 these losses that you said occurred, like the last two 24 l losses you just cited. You didn't indicate why.
m
- 25 MR. SINGH
- You mean these losses here?
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5463 03 03 192 hacrysimons1 MR. MICHELSON: Yes.
2 MR. SINGH: I am sure there were some 3 misoperations in relays. I don't have a lot of knowledge 1
4 about those relays and why they misoperated, but they did.
5 MR. EBERSOLE: So they lost all offsite power.
6 MR. SINGH: The other thing I wanted to point out 7 was that there were other lines coming into this switchyard 8 which were available. In other words, they didn't lose the 9 total switchyard. The switchyard was alive and they had 10 power available to the switchyard, and I am also told they 11 could have restored these lines earlier than 40 minutes.
12 tiR. EBERSOLE: But the bottom line is one unit
_( ) 13 suffered the loss of offsite power?
14 - MR. SINGH: Yes.
15 MR. EBERSOLE: So they have their five-year 16 integral loss in a physical sense. They have already had 17 it. Now where do we stand now on estimated offsite power 18 failures?
19 MR. ROSSI: Alan Rubin is going to address that.
20 MR. EBERSOLE: Okay.
21 MR. WYLIE: The case with the bad bushings, did it 22 blow up?
23 MR. SINGH: I don't know. I hare no idea. All I 24 know is they had a failed bushing which caused all these
() 25 problems.
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5463 03 03 193 llhmarysimons 1 MR. ROSSI: Okay, why don't you go on.
2 MR. SINGH: The third one, I don't have any sketch 3 on that one.
4 This happened on the New Year's Day in the early 5 morning on River Bend. The reactor was in hot shutdown and 6 they lost all offsite power.
7 All diesels started, the TDI diesels.
8 MR. EBERSOLE: That is Louisiana Power and Light, 9 too, isn't it?
10 MR. SINGH: Pardon me?
11 j MR. EBERSOLE: Is River Bend ---
12 MR. WYLIE: That is Gulf States.
13 , MR. EBERSOLE: Gulf States, okay.
k 14 MR. SINGH: The diesels started and picked up the 15 l load and offsite power was restored in about an hour and 15 l
16 { minutes.
l 17 Later I think the following day the investigation 18 revealed that the feeder breakers to both start-up 19 transformers opened as a result of a radio transmitter, a 20 hand-held radio that the guard had.
21 MR. EBERSOLE: Is that a fact.
22 MR. SINGH: Yes. It happened that the security 23 guard was making his hourly round and went into this 24 building, and that building has a tone system. The tone 25 system is a redundant control system for controlling the l
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5463 03 03 194 llhmnrysimons1 breakers to the start-up transformers.
2 Now this tone system was put in because they had a 3 problem meeting GDC-17 because they had some hard wires 4 going to the same trains or something. So this new system 5 was put in, which is a fiber optics system and somehow it 6 kept on picking up the transmitter and actuated the 7 breakers.
8 Now the guard went for the first time and one of 9 the start-up transformers was lost. He went back again, 10 and this time the other one was lost.
11 Now it took the licensee some time to figure out 12 what really happened and they are still investicating.
f 13 They are proposing some fixes and are in touch with the 14 l region.
15ll MR. EBERSOLE: And this phenomenon was not i
i 16 !
anticipated in advance?
17 MR. SINGH: No. This is something nobody knew 18 about. It was the first time. The confirmed that this is 19 what happened by taking people out with radios and talking.
20 MR. EBERSOLE: They didn't put any tone systems in 21 the breaker control circuits for the diesels I gather.
22 MR. SINGH: I don't know.
f 23 MR. ROSSI: Well, you know, the plants were shut 24 down during these events and we have them here to give you
- 25 some flavor of the kind of things that we have really seen ACE-FEDERAL REPORTERS, INC.
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i
'5463 03 03- 195 "lhmarysimons1_ with respect to offsite power systems.
2 Now Alan Rubin is going to say a few words about 3 'the USI, and I think he is also going to talk a little bit 4- about the most recent experience with loss of offsite 5 power.
15 MR. EBERSOLE: You mean.in a general context?
7 MR. ROSSI: Yes.
MR. RUBIN: I would say good morning, but I had 9- better say' good afternoon.
10 ( Laug h te r. ) .
11 My.name is Alan Rubin. I am the Task Manager of 12 Unresolved Safety _ Issue A-44,on Station Blackout.
i( ) 13 (Slide.)
14- And since you have heard this morning about some 15 events with1 diesel generator problems and loss of offsite 16 power, I want to' junt give you- an update on the status of 17 USI A-44.as well as present some information on the recent 18 loss of of fsite power experienced in 1985 and also during 19 previous years. It'will be a fairly brief presentation.
! - 20 This slide shows a breakdown for different year i
21 periods on the numbers of losses of offsite power that have 22 occurred. These are total losses of offsite power.
-23 In the right-hand column the frequency of_ losses 24 of of fsite power per site-year.
~() 25 On average there is a loss of once every 11 site ACE-FEDERAL REPORTERS, INC.
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i 5463 03 03 196 l knarysimons 1" years, 10'or 11 site years. Of- course there are 2 fluctuations from year to' year. There have been some years-3 where .there have been losses of off-site power and there 4 have been other years.with a frequency that has been
'5 greater than .2 per site year.
6 MR. EBERSOLE: An observation.
7 MR. RUBIN: Yes.
8 MR. EBERSOLE: I don't like to talk about the 9 ' general frequency in the absence of a distribution that 10 tells me where the worst five plants are-or something like
-11 that. So will you tell me where they are and what ---
12 MR.. RUBIN: . There are some plants that have had- i 13 three or four losses of offsite power.
f) 14 MR. EBERSOLE: Per year. ,
15 MR. RUBIN: No, not per year, but over their 16 lifetime. There are others that have.had none.
17 MR. EBERSOLE: Well when you talk about this, 18 let's not talk about the general distribution -- we want to 19 know the worse half dozen or so.
20 MR. RUBIN: I didn' t bring the specific data for -
21 each plant, but we do have a report that has been issued ,
I 22 both by -- a contract report by Oak Ridge National 23 Laboratories and also EPRI has issued a report which lists 24 all losses of offsite power at the plants where they
() 25 1.
occurred.
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8
?
5463 03 03 197 llhmcrysimons1 MR. EBERSOLE: And then that has to be correlated 2 with reliability of the onsite power.
3 MR. RUBIN: Well, for resolution of A-44 that is 4 correct.
5 MR. EBERSOLE: Okay, go ahead.
6 MR. MICHELSON: When you talk about loss of 7 offsite power, did you include the cases where the 8 switchyard remains energized and you simply can't wield it 9 in?
10 MR. RUBIN: Yes, a loss not to the switchyard, but 11 a loss to the essential buses. They may have power in the 12 switchyard, but they cannot be powered to the load bringing 13 it in.
I 14 ] In the resolution of A-44 we used a general 15 average, but broke down plants by their characteristics in 16 terms of AC power reliability. That average was about .08 17 to .09 for losses per site year.
18 The second two lines on here is taken from a 19 report by EPRI where they have indicated for years previous 20 to 1971 there was a higher frequency in losses of offsite 21 power than for the three-year period of 1982 to 1984.
22 During those three years there was less than half of the 23 , frequency of loss of offsite power than for all previous 24 years.
I 25 For the year 1985 there were eight losses of ACE-FEDERAL REPORTERS, INC.
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5463 03 03 198 llhmerysimons1 offsite power, which is again a frequency that is higher 2 than generally average, but within an expected range that 3 you would see based on the data that we have seen in the 4 past.
5 When the NUREG report was issued, and this is 6l NUREG 1032, it was issued for comment in the early part of 7 1985. We got comments from industry saying the last three 8 years of losses of offsite power have been better than in 9 the past. We expect this to continue in the future and 10 therefore station blackout is not such a significant safety 11 issue.
12 For 1985 the losses are higher than the previous 13 [ three years, and I just want to make the point to exert 14 l some caution when looking at a limited amount of data, 15 either limited in terms of plant or limited in terms of tho 16 j number of years.
l MR. EBERSOLE: On what basis did the industry make 17 l 18 that claim that we are getting better?
19 MR. RUBIN: What is reported here is that this was 20 the experience for losses of offsite power for 1981 with a 21 frequency of about .1 per site year. In the three years, 22 '82, '83 and '84 there were only seven losses with a 23 frequency of only half of that.
4 24 MR. EBERSOLE: So how did they manage to turn up 25 the basis for making that report?
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5463 03 03 199 lllmnrysimons1 MR. RUBIN: These were actual data. For '85 just 2 ended we had a fairly significant number of losses at the 3 end of 1985.
4 MR. MICHELSON: Loss of of fsite power is for any 5 duration?
6 MR. RUBIN: Any duration, yes.
7 MR. MICHELSON: I would like to see a distribution 8 a little bit of a duration of events.
9 MR. RUBIN: The reason I didn't bring that, and 10 this is sort of an update that we have presented to the 11 ACRS Subcommittee on Electrical Power Reliability in the 12 resolution of A-44. A lot of the background information, 13 including distribution, I can make it available. It is 14 also available in the NUREG 1032 report that I referred to.
15 (Slide.)
16 We presented to the ACRS aubcommittee and the full 17 committee back in March of 1985 the proposed resolution for 18 Usi A-44. This is just a very brief overview of what the 19 elements of that resolution are.
20 One is to publish a proposed rule for comment that 21 would require all plants to be able to cope with a station 22 blackout for a certain period of time.
23 The second would be to issue in support of that 24 rule a regulatory guide that would giva guidance on the c
25 time that plants would be required to cope with a station
-)
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'5463 03 03 200 kusrysimons1 blackout as well as providing recommendations for 2 maintaining minimum reliability on emergency power sources 3- and having procedures for training both to cope with a 4 blackout and to restore AC power after the loss.
5 MR. EBERSOLE: So what is the status?
6 MR. RUBIN: The status is coming up in the next 7 slide.
.8 (Slide.)
9 The backup slides on this give a little more 10 breakdown on these recommendations, but I won't present 11 them here.
12 MR. WARD: Let's see, a question on the
.x
-f .
13' resolution.
14 MR. RUBIN: Yes.
15 MR. WARD: Alan, where does the reactor coolant 16 pump seal leakage issue stand?
17 MR. RUBIN: It stands right now -- there -is not a 18 proposed resolution yet. Where it fits into A-44 is that 19 for this station blackout duration the pump seals would 20 need to be -- it would need to be shown that the pump seals 21 would maintain their integrity and that primary inventory 22 would not deplete those if the core couldn't be cooled.
23 There is information that the staff has made a 24 number of times to the Westinghouse owners group. There
() 25 was a test conducted in France in the middle of 1985, a ACE FEDERAL REPORTERS, INC.
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5463 03 03 201 llhmcrysimons1 full-scale test of the pump seals, the Westinghouse pump 2 seals, which was very successful in terms of maintaining 3 seal integrity for that particular test.
b 4 MR. WARD: Does the staf f consider that test 5 result definitive?
6 MR. RUBIN: The staff is reviewing that test and 7 evaluating it and has not come to a recommendation that 8 that would resolve the issue or not.
9 MR. EBERSOLE: In that connection, Dave, as you 10 were saying, this rate of leakage, is it established by 11 metal-to-metal gap clearances or is it dependent on 12 degradation of elastomers or other flexotalic types of 13 seals that are subject to heating degradation?
14 MR. RUBIN: There are several modes of failure, 15 ' but one primary consideration is the degradation of the 16 secondary seals, the o ring seals, the elastomers, that if 17 they did f ail, then the seal faces themselves could 18 disintegrate.
19 MR. EBERSOLE: Then we are still dealing with the 20 rather ambiguous aspect of what is the consequence of 21 heating on some sort of elastomer-like substance rather 22 than actual piston ring type metal-to-metal clearance.
23 g MR. RUBIN: That is correct. Well not only that, 24 but that has been certainly a large focus.
25 MR. EBERSOLE: If we had metal-to-metal clearance ACE-FEDERAI. REPORTERS, INC.
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5463 03 03 202 lhmnrysimons1l fixations on this, we wouldn't have any problem.
2 MR. RUBIN: We don't expect the metal to 3 disintegrate as the movement of the seal faces.
4 MR. RUBIN: And these other preparatory compounds 5 that you really wonder about that are the source of the 6 problem.
7 MR. RUBIN: Right. Westinghouse based on some 8 tests of elastomer seals has been proposing to replace the 9 secondary O ring ---
10 MR. EBERSOLE: But those would also be elastomers, 11 MR. RUBIN: Yes, but a different compound that has 12 withstood temperatures and pressure conditions that we l
13 expect to see during a station blackout.
14 l MR. EBERSOLE: However, they are no way comparable 15 !j to metal clearances to limit leakage rates.
I 16 )i MR. RUBIN: Well, they look at the limit leakage I
17 rates both through the separation of the space seals and 18 also the breadth of the discharge path ---
19 MR. EBERSOLE: Maybe the can find some that will 20 swell up when they get hot.
, 21 Go ahead.
- 22 MR. ROBIN
- Let me get back to A-44. But the two 23 issues are very closely related. We discussed that issue 24 and others during our previous ACRS presentation.
25 (Slide.)
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'5463103 03 203 llhntrysimons1 The status right now is that the proposed rules 2 has been presented to the Commission in meetings in 3 September and November of 1985. We just received a memo 4 from the Commission dated December 31st. The Commission 5 will issue a proposed rule for comment.
6 They have also requested that we provide the 7 Commission with a backfit analysis before issuing the 8 proposed rule, which we are prepared to do.
9 We expect to issue the proposed rule shortly for 10 comment and then go through the receipt of public comments 11 and see what happens in terms of the final rule based on 12 those comments.
-( ) 13 You can see here that the time frame between 14 issuing the proposed rule and a possible final rule is 15 fairly long. We won't be issuing a final rule until 16 sometime in mid-1987.
17 We will keep the ACRS informed, and when the 18 proposed rule goes out we will send you a copy of both the 19 rule and the regulatory guide ard any other related data.
20 MR. EBERSOLE: Thank you.
21 MR. ROSSI: Let's see, I had somebody from the 22 licensee's staff on Waterford that said they wanted to say 23 a couple of words.
24 MR..EBERSOLE: Mr. Ken Cook wanted to say a word
() 25 about Waterford 3.
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5463 03 03 204 hharysimons'l MR.' COOK: I am Ken Cook from LP&L. I just wanted 2 to try to, if I could, put the Waterford loss of offsite 3 power into a little different perspective.
4 I think it is a fairly complicated sequence of t-5 events and .Rabi showed a lot of relays that were went out 6 'and were.put back in automatically and. operator actions and
- 7_ everything.
8- All of that can really be summed up.to the. fact 9 that throughout-that whole sequence of events the Waterford 10 switchyard still had power available. The only reason we 11 didn't have power at the Waterford 3 plant itself was the 12 .comparator relays that he showed on that.one chart.
Those particular relays went out only because we
(
Dr~)5. ~13-14 were shut down at the time. The ground current 15 contribution from our startup transformers was enough to 16 cause tripping of those relays and took outside power away:
- 17. from the plant.
18 If we had.been running at the time,'that wouldn't' i '
19' have occurred. We would not have had a loss of .offsite 20 ~ power.- We hbve sinco changed. the settings on those relays
- 21. so it will not happen when we are shut down again.
22 So even though there were a-lot of events and a 7
23 lot of things that happened outside of the Waterford
~24 . switchyard, if we had been running or that event were to O
- lgj 125 occur today, we would not have a loss of of fsite power s
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'L5463103 03 205 9^p L Lmcrysimons-1 event.
2 MR. EBERSOLE: The second part of your comment I 3 think is extremely important, tha t it wouldn' t happen 4 today.
5 -The first part, if you were running, is not 6 particularly significant since life begins af ter you have 7 tripped and you still have to remove decay heat. Do you 8 follow me? -
9 - MR. COOK: That is true. But I j us t wan ted to 10 point out that in terms of being a full loss of offsite 11 power that it has some special features associated with it, 12 because right now that event would not recur if the same
(~
(_)) 13 sequence of events everywhere else within the sys tem 14 happened as happened at that time and we would still have
-15 offsite power available.
16 MR. EBERSOLE: Even if you weren' t running.
17 MR. COOK: Even if we weren' t running.
18 MR. EBERSOLE: That is the part that counts.
19 MR. COOK: That is right.
20 -MR. EBERSOLE: I mean af ter all that is when the 21 plant starts to get nervous when it is not running.
22 MR. COOF: And I think Rabi mentioned that we 23 could have restored pot;er a little quicker. Our operators 24 found that the diesel generators were running and supplying
() 25 the load, and that was their primary interest at that ACE FEDERAL REPORTERS, INC. (
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- 5463'03 03 206 q
~4 /marysimons 1 time.: Rather than asking for the southern control 'to get 2 power back to the plant, they were -making sure that the 3 emergency sources were operating properly.
4 MR..EBERSOLE: Well thank you.
5 Ernie.
6 MR. ROSSI: Okay. We' have just one more item, and 7 that is a Hatch problem with flooding when the plant would 8 shut down, and that will be discussed by George Rivenbark
.9 from NRR.
10 MR. EBERSOLE: Again, why do you say when it was 11 shut down? That is when life begins when it is shut down.
12 MR. ROSSI: Well, some things I thing it is more
-( j 13 difficult to correct.
Maybe you can say some words about 14 whether- this one ever could have occurred to the plant.
15 MR. RIVENBARK: I don' t think so. I don' t think j 16 it could have occurred.
17 MR. ROSSI: That is why he said with the plant 18 shut down.
19 MR. EBERSOLE: Okay.
.20 MR. RIVENBARK: I am George .Rivenbark, the ' Ha tch
, 21- ' Projec t Manager.
- j. 22 (Slide.)
23 The problem with this Hatch event was simply that 24 the RHR pump room was accidentally flooded during and as a
( ). 25 result of some maintenance activities.
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' j marysimons 1
_ The situation at the time was tha t Unit 1, which 2 is the unit in which the flooding occurred, was totally 3 shut down and the fuel was in the fuel storage pool. It 4 had been removed from the core.
5 ( Slide . )
6 Maintenance was being performed on a valve -- and 7 I am sorry about the ske tch , but it will serve a little bit 8 o f a pur pose . Maintenance was being performed on the 9 second valve away from the torus in the suction line to an 10 RHR pump.
11 The pump had failed a leakage test just previously 12 and so they had decided to work on this pump to remove the 7
(_) 13 internals and to repair it.
14 The valve upstream of that, the valve closest to 15 the torus is an air operated valve. It had been tagged out 16 for the leak test, and it remained tagged out when they 17 decided to repair this valve.
18 MR. EBERSOLE: When you take out a valve like 19 that, what do you do? You leave it subject to operational 20 e rror , don' t you , to open if you don' t lock it up 21 mechanically.
22 MR. RIVENBARK: That is my understanding.
23 MR. EBERSOLE: So it is not really key locked or 24 fixed in place so it really can ' t opera te .
o
(_) 25 MR. RIVENBARK: If you did what you said, it could ACE-FEDERAL REPORTERS. INC.
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.A i ( )carysimons 1 no t ope ra te .
2 MR. EBERSOLE: Right. You leave it vulnerable to 3 ope ra tion .
4 MR. ROSSI: That is the whole crux of this event.
5 MR. RIVENBARK: If you will notice up here ,- you 6 can follow this poor maintenance procedure.
7 MR. EBERSOLE: Is that generic to the total 8 maintenance picture? Is that the safe ty switch tha t -
9 doesn't have a lock on it?
10 MR. RIVENBARK: I don' t know if that is generic to 11 the total maintenance picture or not. I believe that most 12 people in most instances would mechanically block that
('3
,) 13 valve.
14 MR. EBERSOLE: I guess what I would get at is why 15 aren' t they required to do so?
16 MR. RIVENBARK: Their maintenance procedure is 17 vague.
18 MR. EBERSOLE: Okay. If it is vague here, it is 19 probably vague everywhere.
20 MR. RIVENBARK: We ll, I can' t say tha t. I am sure 21 that some places it is not vague at all.
22 MR. EBERSOLE: Okay. Go ahead.
23 MR. RIVENBARK: Anyway, so this valve was just 24 tagged out. They were doing some tests on the diesel I
() 25 generator. At the same time they had this valve open and ACE-FEDERAL REPORTERS, INC.
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5463 03 03 209
)marysimons 1 were working on it, they were testing the diesel generator, 2 and this is their refueling outage test of the diesel 3 generator. And during this they dropped a 41-60 volt line 4 which powers a 600-volt source, and it opened this 5 solenoid.
6 The aid fled out through the solenoid and the 7 valve opened. It began to pour water into the southeast 8 RHR pump room.
9 (Slide.)
10 There are two RHR pumps and one core spray pump in 11 this room. It filled it up un til about the 14-foot level, 12 which was close to, as I understand it, that they thought
() 13 initially that was the equilibrium level with the torus, 14 but later it turns out what had actually happened was the 15 valve was reclosed. Power was put back on within 10 16 minutes. They were continuing their test with the diesel 17 generator and they got the power back on, but the y we re n' t 18 in a hurry to do it at the time.
19 When the power came back on it closed the block 20 valve and stopped the flow. Well, they ended up with the 21 whole 14 fee t of water in that room and they didn' t know 22 why at the time because they didn' t realize what had 23 happened.
24 So the shif t supervisor not knowing exactly what
/m
!) 25 had occurred decided that he wanted to get the water down ACE. FEDERAL REPORTERS, INC.
202-347-3700 Nationwide Cmerage W-33MM4
5463 03 03 210 7 ~g (jmtrysimons 1 in that room to find out what was going on and where did 2 the leak come from.
3 (Slide.)
4 So wha t he did was he sen t two ope ra tors down . He 5 sent one to the other RHR pump room and one into this HPCI 6 room to watch the water level in there as he began to 7 , dowater this.
8 This is a situation where the sump pumps are in 9 the northeast RHR pump room. To dewa ter this room you have 10 to pump over to this sump. So in dewa tering this, he sent 11 a man here and a man here , and they controlled the pump out 12 to the processing and storage building.
?"\
(_) 13 So the water level got up about two feet high here 14 and about one foot high in this room during that process 15 and actually they spilled some also a few inches into the 16 floor of the waste storage building, which is, as I 17 understand it, an occasional occurrence. Whenever they 18 build the tanks over there, the floor is designed to catch 19 wa te r .
20 MR. MICHELSON: You didn' t mean to point to the 21 HPCI compartment, did you?
22 MR. RIVENBARK: Ye s , I did.
23 flR. MICHELSON: How does the wa ter ge t in there?
24 MR. RIVENBARK: I believe the water came i t -- it O.,
()_
25 is my understanding that when you open these valves they ---
ACE-FEDERAL REPORTERS, INC.
l 202 3474 700 Nationwide Cmcrage 800-3 % 6646
1 5463 03 03 211 marysimons 1 MR. MICHELSON: Well, the other valve is closed. i 2 MR. RIVENBARK: We ll , I think the same switch is 3 open to this one and -open to that one. I ' think they are
~
4 ganged.
5 MR. MICHELSON: Tha t may be .
6 .MR. RIVENBARK: That is my understanding. 'So some 7 water got in here .
8 MR. GREEMAN: That is my understanding. Tha t is 4
9 controlled.
10 MR. EBERSOLE: But tha t doesn' t apply to the lower 11 . corners , does it? They are separate.
12 MR. RIVENBARK: This is a separato system over
~
13 here.
14 MR. EBERSOLE: Okay.
15 MR. RIVENBARK: The follow-up action was that the 16 Realon sent a team of folks down there to find out what had 17 happened. They wanted to look over. the operational event 18 and find out what the maintenance practice was and see what 19 they were going to do about restoring the equipment that 20 was damaged.
21 Now they did find that the licensee's procedure 22 -was vague. It says something tha t is the equivalent of 23 take appropria te ---
24 MR. EBERSOLE: Do good.
> . () 25 MR. RIVENBARK: . Something of this nature. And the ACE. FEDERAL REPORTERS, INC.
202 347 3700 Nationwide coverage 8m336 6M6
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'5463103 03- 212 r- <
! ,%/ marysimons 1 other thing where they screwed up, not only that one, but 2 they didn't whenever they got Leady to perform the diesel 3 test , eval ua te the configuration of the system at that 4 particular time to see what would be the impact oa the 5 system of doing the diesel test. So that was a couple of 6 things that could go wrong.
7 MR. EBERSOLE: Was NRC there to be prescriptive
.8 beyond telling them to do good.
9 MR. RIVENBARK: Well you know the NRC is never 10 pre scriptive .
11 ( Laughte r. )
' 12 Now le t's see . The licensee's follow-on action is
-( ) 13 developing a be tter maintenance procedure so that it can be 14 a little bit more specific in making sure that the valves 15 ge t blocked out and other thingo are taken care of. And 16 they are also _getting a test program together so that they 17 train their -- I mean a training program to train the 18 operators with the procedure.
19 MR. EBERSOLE: We ll certainly from a judgmental 20 standpoint it was foolish to let a valve be cocked for 21 trouble on the loss of air when you opened the pipe.
22 Somebody at the top end of the maintenance structure needs 23 to be chewed on. I don't know who it is.
24 MR. RIVENBARK: I don' t think anybody, including
' () 25 the licensee , would disagree with you. The licensee is ACE FEDERAL REPORTERS, INC.
202 347 3700 Nationwide Coverage 8m336-fM6
5463 03 03 213 ccrysimons 1 currently evaluating each piece of equipment in that room 2 to see whe ther they can be restored or whe ther they have to 3 be replaced. One of the vendor's recommendations is drying 4 it out or whatever.
5 MR. EBERSOLE: You submerged the RHR punps.
6 MR. RIVENBARK: Ye s .
7 MR. MICHELSON: Did the RHR compartment pipe 8 pene trations all hold all right?
9 MR. RIVENBARK: Ye s . I was told that they paid 10 particular attention to seeing if it was as tight as they 11 had intended to design it. It did not leak.
12 MR. EBERSOLE: Well thank you very much.
13 Any questions on this?
14 (No responso.)
15 There remains, and we are running 20 minutos lato, 16 but thoro -- Ernio, is that i t?
17 MR. ROSSI: Tha t is all we have. Now we have to 18 decido what you want to hear about on Thursda y.
19 MR. EBERSOLE: To got started on this, I am going 20 to suggest that we take the two events that pertained to 21 Babcock and Wilcox plants, the B&W plants, which was 22 Rancho Soco and Crystal River, and sort of consolidato them 23 into a single shortened prosentation, if that can be done.
24 MR. ROSSI: Unfortunately, we have got two project
/
(,)T 25 managers. So what wo probably will do is shorton the two Acti FlilMIRAl. RI!PonTrins, INC.
202.m.nm Nationwide cmenge 84nnuu6
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i 6 .5463 03 03. 214
( Imarysimons 1 presentations and have each one do their own because I 2 think each project manager is going to have to answer 3 questions on his own plant.
4 MR. EBERSOLE: I think we certainly need to take 5 to the full committee Mr. Rubin's presentation on the 6 status of A-44.
7 MR. ROSSI: Okay. You don' t want to hear about 8 the specific events.
9 MR. EBERSOLE: No, no, no, I don' t. That was just 10 again a triggering event about why we want to have a look 11 at this again.
12 MR. ROSFI Okay. So you want Rancho Seco and
() 13 Crystal River and USI ---
14 MR. EBERSOLE: The Indian Point thing as you have 15 i t he re , bu t i t will be in the generic context.
16 MR. ROSSI: Yes, not the events, but the Alan 17 Rubin part on USI A-44 and the statistics.
18 MR. EBERSOLE: I thought it was interesting enough 19 to take to the full committee the dual unit trip on loss of 20 instruments there. That is at McGuire?
21 MR. ROSSI: Yes.
22 MR. EBERSOLE: Just in the context of noting how a 23 small failure in the secondary equipment can lead to a 24 massive secondary system failure and thus challenge
() 25 numerous safety systems. Tha t is McGuire 1 and 2.
ace-FEDERAL REPORTERS, INC.
202 347 3700 Nation *ide Coverage 800-336-6 4 6
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L 5463 03.03 215
)mcrysimons1 On the internals lif ting rig failure, there again 2 I would use that as a triggering event to have a look at 3 where we finally converged on the USI heavy loads issue.
4 What was it, A -- I forge t what it is. A presentation with
.5 that in the background as to where we stand on heavy loads.
6 And, finally, the last one I had here, and I 7 invi te the subcommittee to add or subtract from this, the 8 main feedwater failure auxiliary feedwater actuation t l 9 reactor trip on Crystal River 3.
L 10 MR. ROSSI: Well, you have that one. That was ,
11 par t o f ---
12 MR. EBERSOLE: Oh, that is right. I already had
( k 13 that. I overran that.
L 14 MR. ROSSI: So it is Rancho Seco, Crystal River,
- 15 McGuire 1 and 2, and then you really want to hear about, 16 not so much the events, but you want to hear about USI A-l- 17 44.
18 MR. EBERSOLE: These seem to be events, these i
19 individual events that call up a need to have a look at f
20 where we = stand on the generic aspects.
I
! 21 MR. MICHELSON: You don' t think the Peach Bottom 22 RHR loss of so many pumps and loss of all wear rings and so i 23 forth is not important?
24 MR. EBERSOLE: I didn' t think that was anything 25 fast moving enough to ge t nervous about.
l I
! Au:E. FEDERAL REPORTERS. INC.
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' !,_,lecrysimons 1 MR. MICHELSON: Well, depending on whether you are
)
2 a materials person or not, tha t could be very nerve 1 3 racking.
4 MR. EBERSOLE: But the se things have been running ,
l l 5 since '74 and they are not likely to all go out at once. ]
6 MR. ROSSI: If you get too many on, you know, we i
7 have spent nearly five hours today I guess going through 8 this.
9 MR. EBERSOLE: Right. We will be pinched I think 10 with just these.
- 11 MR. ROSSI
- Ye s . We will not then come back to ,
l 12 talk really in any detail at all about St. Lucie 1, but we
(
(~%
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(_) 13 will have somebody here to answer your questions, or NRR L 14 will have somebody to answer your questions.
1 15 MR. EBERSOLE: What was St. Lucie on? Oh, no,
! 16 tha t is right. Not St. Lucie 1. That is just a single l
17 unique event.
18 MR. ROSSI: Ye s . That is why I say you want to 19 hear about the USI A-44 heavy load thing.
20 MR. EBERSOLE: Right.
t 21 MR. ROSSI: Now on McGuire 1 and 2 you did ask a
( 22 number of questions about the air systems and systems l
l 23 in te rac tion .
24 MR. EBERSOLE: Well, this has been a continuing
() 25 concern of the committee of what can air or loss of air do s
! ACE. FEDERAL REPORTERS, INC.
202 347 3700 Natkmaide Cmcrage 800 3 4 6646
I 5463 03 03 217 p
_)ctrysimons 1 or excess air pressure or water in the air. Air is a 2 current area of great interest I think.
3 MR. ROSSI: Okay. I had some specific things that 4 you asked. You wanted to know whe ther there were other 5 failures in the event and whether they had analyzed the 6 loss of air system at that time.
7 MR. EBERSOLE: Yes.
8 MR. ROSSI: And I think somebody answered that 9 today. I thought someone from NRR answered that.
10 MR. EBERSOLE: What wasn' t really answorod was the 11 probability of loss of air consistent with the consequenco 12 of it, which was very ---
() 13 MR. ROSSI: We will do our best to got answers on 14 those. Now keep in mind the f act that wo are coming down 15 from the events perspective and these USI's are handlod by 16 a lot of other people within the agency. So we will got 17 wha t we can on thoso.
18 MR. EBERSOLE: We ll , I guess these are spot ovents 19 in a larger picture.
20 MR. ROSSI: Ye s , a nd wo try to bring the ovents 21 down horo so you will have a flavor of what is going on, 22 and wo also send them over to the poople who are working on 23 the USI so they in general know what is going on, too.
24 MR. WYLIE: Well, I am not sure that that has O 25 really boon answorod about the McGuiro as to whether or not
( ,j ace-FEDERAL REPonTERs, INC.
202..t47-17(10 Nation.Ide Cmerage
- n UMM6
l i
5463 03 03 218 ccrysimons 1 there is a commitmen t to run a formal, documented system 2 interactions study as a program by the utility.
3 MR. ROSSI: Right. That was addressed in every 4 plant that you wanted to know on tha t one .
5 MR. EBERSOLE: Ye s .
6 MR. WYLIE: I mean is that a commitment?
7 MR. ROSSI: Well, we will bring somebody ---
8 MR. EBERSOLE: Se e , this is really clear evidence 9 that that is not being done very well.
10 MR. REED: Why, Jesse? Why is that evidence?
11 MR. EBERSOLE: You don' t want to lose a string of 12 units just because you bust an air line. l O 13 MR. Reed: Thee is the besis ee desion.
14 MR. EBERSOLE: No, no, I am talking about ---
15 MR. REED: Challenges are good in my opinion. .
16 MR. EBERSOLE: Look, it takes two things, Glen, to 17 cause problems, a challenge frequency and a reliability 18 index. If you don' t ever challenge anything you don' t need 19 it.
20 MR. WYLIE: I think the more significant question 21 is are they looking at anything?
22 MR. EBERSOLE: Well, tha t may be true, too.
r 23 MR. ROSSI: You really want a quick status of USI !
T 24 on systems interaction. That is what you really want, and l O 25 the Mccuire event simniv eriooered thee. 1 Act!.Fl!DERAL RI! PORTERS, INC.
202 347 3700 Natlon*kle Cmerage 800 3M fM6
l 5463 03 03 219 p
( ,lorrysimons 1 But, you know, going back to the McGuire one, it 2 was a non-safety related system that caused challenges to 3 the safe ty systems , and I suspect if they are doing 4 anything on systems interaction that that ovent would be 5 outside of it anyway unless it actually interfered with the 6 operation of the safety systems, which I don' t think it 7 did.
8 MR. EBERSOLE: Well, you know, Ernio, GDC-17 is an 9 attempt to diminish challet ges to diosels and you can apply 10 it to air as well. We just haven' t dono it.
11 MR. ROSSI: I think a lot of people are concerned 12 about the challongos and the complications that are caused O
(_/ 13 by those non-safety related systems. All I am doing is 14 stating the facts as they are. We are limited in how far 15 we can regulato in those areas in what we are doing today.
16 MR. REED: I look upon challongos as only 17 unexpected surveillance te s ting .
18 ( La ug hte r. )
19 Ilo y , that is what it is. You guys are challenging 20 systems all the time with surveillanco testing and its 21 frequoney. Challongos, if overything works fino, I think 22 they are great. The y a re une x pec ted .
- 23 MR. WARD: You wouldn' t carry that all the way to l
24 the largo break LOCA, would you?
' /~3 (j 25 (Laughter.)
l i
! Acit Fl!DL'RAL Rt!PonTI:ns, INC.
202 347.)?m mtion.ue cmerage mnno ua6
5463 03 03 220
{}/
(, marysimons 1 MR. REED: Well, those are things tha t you don' t 2 oven do surveillance tests on.
3 MR. EBERSOLE: Clon, the components of the safety 4 problem is challenge frequency, reliability of the response l 5 systems and the consecuences of failure of that, and that 6 is the recipe.
7 MR. ROSSI: Don Hernan wants to say something from 8 NRR.
9 MR. EBERSOLE: Ye s , s i r .
10 MR. IIERNAN: I have about four things I want to 11 say.
12 There was one question on relay chatter that came n
(_.,) 13 up I think during the loss of AC power.
14 MR. EBERSOLE: That was a question of sort of a l
15 generic charactor.
16 MR. WYLIE: But that really is a systems 17 Interaction ---
10 MR. EBERSOLE: It is.
19 MR. IIERNAN: What I want to say is the staf f doos 20 intend to go down to tho appropriato subcommittoo on 21 January 15th and discuss USI A-46 on tho soismic equirmont 22 qualification. Wo think tha t would bo tho appropriato 23 quorum to talk about that.
24 MR. EBERSOLE: Noll, the bounds of tho
()
(y 25 electrically qualified system should cortainly includo the Aci! Fliniinai. Rt!PonTiins, INC.
202.)n.37m Natlonwide Cmcroc MaM4mm
5463 03 03 221
(~
I_)ccrysimons1 relay network that this connects loads and maintains the 2 disconnect or lockout.
3 MR HERNAN: And we would hope to talk about that 4 in the USI A-46 discussion.
5 MR. EDERSOLE: Okay.
6 MR. IIERMAN: On systems interaction our present 7 plan does includo within the next two months to como on USI 8 A-17.
9 MR. EBERSOLE: Well, we can tell the full 10 commi ttoo this. Fino. Good.
11 MR. ROSSI: So I think what you are really saying 12 is that the more appropriate forum for talking about tho
() 13 USI's is whon we como down, and you ought to perhaps bring
(_/
14 your questions that are triggorod by thoso events up for 15 that discussion. That is probably bottor anyway because 16 when you try to cover all that in an hour and a half on 17 Thursday ---
18 MR. EBERSOLE: Wo can ' t ma ko it. I agroo.
19 MR. ROSSI: So we will talk about the McGuiro 1 20 and 2 ovent and then poople can remember it whon they got 21 into the systems intornction. Wo won' t try to address tho 22 gonoric issuo.
23 MR. ERERSOLE: Right.
24 MR. IIERMAN: Thoro are two other thingn I want to
() 25 montion. Thoro was a significant ovent at San Onof ro 1 as Aci!.Fi!DlillA1. Rill'oitTiilts,1NC.
202an.no Nation. Lie cmcrne mon wo
____-_______-__________-]
I-
, 5463 03 03 222 I ncrysimons 1 you are probably aware of a couple of months ago with a H
2 loss of all AC and a feedwater rupture.
3 MR. EBERSOLE: Ye s .
4 MR. HERNAN: We had hoped to be able to come to ,
5 this subcommittee today with this issue. However, the 6 investigating team report will not be out for a couple more 7 wee ks . So the agreement with the ACRS staf f is to come l
8 down at some appropriato time af ter that report is issued.
9 MR. EBERSOLE: Sure.
10 MR. HERMAN: Finally, there is a possibility of 11 maybe having to have this subcommittee meet again next 12 mo r, th .
() 13 MR. EBERSOLE: It is already set up. What is the 14 date?
15 MR. ALDERMAN: The lith of February.
16 MR. EBERSOLE: Okay.
17 MR. HERNAN: That is all I have.
18 MR. MICHELSON: Ouostion.
19 MR. EBERSOLE: Yes, sir.
20 MR. MICllELSON: Since you are not going to discuss +
21 the RilR pumps further, let me ask a question which I was 22 going to delay until next time.
23 You indicated that Browns Ferry was the other 24 plant that had nimilar problems. Itavo you sont out an
() 25 information notico or has tho jungle telograph sont out a Act!. Flint!RAI. Riii>onit!Rs, INC.
202 umm Nakm klecmerne mowimi
I 5463 03 03 223 p.
O marysimons 1 notice at least?
2 MR. ROSSI: I think that they are aware of it 3 now. Of courso, the plants are shut down. But wo do have 4 an information notico under preparation on that.
5 MR. MICHELSON: Now my question is are you going 6 to require that they inspect the pumps before they start 7 up?
8 MR. ROSSI: I don' t know what the decision with 9 ro upoc t to Drowns Ferry will be.
10 MR. MICHELSON: Because if you don' t require 11 inspection, I think a few more questions nood to be asked.
12 MR. ROSSI: Well, we have the same concerns that O
O 13 you do.
14 MR. MICHELSON: Thank you.
15 MR. EBERSOLE: Any furthor questions?
16 (No responso.)
17 MR. EBERSOLE: If not, you can go eat I quoss.
18 (Whoroupon, at 1:45 p.m., the nubcommittoo 19 adjournod.)
20 ******
21 22 23 24 (O) 25 ACl!lil!DliitAI, Rl!!'OirMMIS, INC.
202.m.3w Naikm.ide cmerage mim mm
CERTIFICATE OF CFFICIAL REPORTER ry y/
l This is to certify that the attached proceedings before the UNITED STATES NUCLEAR REGULATORY COMMISSION in the matter of NAME OF PROCEEDING: ADVISORY COMMITTEE ON REACTOR SAFEGUARDS REACTOR OPERATIONS SUBCOMMITTEE DOCKET NO.:
PLACE: WASl!INGTON, D. C.
DATE: TUESDAY, JANUARY 7, 1986 were held as herein appears, and that this is the original I transcript thereof for the file of the United States Nuclear Regulatory Commission.
. (siot 1*
(TYPED)
MARY SIMONS
[ [
l l
Official Reporter ACD-FEDERAL REPORTERS Reporter's Af filiation, INC.
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j NRR STAFF PRESENTAT,10N TO THE ACRS i
l
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SUBJECT:
STATUS OF USI A-44, STATION BLACK 0UT DATE: JANUARY 7, 1986 t >
.; PRESENTER: ALAN M. RUBIN PRESENTER'S TITLE / BRANCH /DIV: TA MANAG R RE ISSUESBRANCH,DIVISIONOF.SAFETYREVfkW8OVkR$1GihC10RS PRESENTER'S NRC TEL. NO.: 49-28303 SUDCOMMITTEE: SUBCOMMITTEE ON OPERATING REACTORS O
pp.,,, ** ' =
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9 STATUS OF USI A-44, STATION BLKK0l!T PRESENTATION TO THE ACRS SUBCOMMITTEE ON OPERATING REACTORS BY ALAN M. PUBIN
$ DIVISION OF SAFETY REVIEW P, OVERSIGHT OFFICE OF NUCl. EAR REACTOR REGlit.ATION JANUARY 7, 1986 i
4
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\ /
l.0SS Cf 0FFSilE P0llER (IPSP) FPECUEi4CY TOTAL FPEQUENCY OF LOSP YEARS SITE-YEARS LOSP (PER SITF-YEAP)
ALL YEARS SP,8 49 0.08 TilROUGil 1984 l
Al.L YEARS 431 42 0.10 THROUGH 1981 l
1987 - 84 157 7 0.046 2S85 6 8 -
O ALL YEAPS 643 57 0,09 THP00Gil 1985 CONClllSIONS INDUSTRY AVERAGE TOTAL LOSS OF 0FFSITE POWEP IS ABOUT ONCE EVERY 11 SITE-YEARS, Tile FRE0VENCY OF TOTAL LOSS OF 0FFSITE POWEP CAN VARY FROM YEAR TO YEAR, ONE MUST BE CAUTIOUS WHEN USING A LIMITED SET OF DATA TO ESTIMATE FUTURE LOSP FREQUENCIES, l
O l
m
$)
RECOMMENDATIONS FOR RESOLVING USI A-44 PUBLISH PROPOSED RULE WHICH WOULD REQUIRE ALL PLANTS TO BE ABLE TO WITHSTAND AND REC 0VER FROM A STATION BLACK 0UT OF A SPECIFIED DURATION.
ISSUE DRAFT REGULATORY GUIDE IN SUPPORT OF RULE GUIDELINES FOR ALL PLANTS PROCEDURES AND TRAINING TO COPE WITH STATION BLACK 0UT MINIMUM EDG RELIABILITY GUIDELINES CONSIDERING PLANT DIFFERENCES
() HOW TO DETERMINE ACCEPTABLE TIME TO WITHSTAND STATION BLACK 0UT l
O
i C f USI A-44 SCHEDllLE AND MILESTONES l
MILESTONE pfATE
! PRESENTATION TO ACRS SUBCOMMITTEE ON FEBRUARY 1985 ELECTRICAL SYSTEMS PRESENTATION TO FULL ACPS MARCH 1985 ;
LETTER FROM ACRS TO EDO MARCH 1985 ,
DRAFT NUREG-1032 PUBLISHED MAY 1985 PROPOSED RllLE (SECY-85-163) TO COMMISSION MAY 1985 SECY-85-163A TO COMMISSION SEPTEMBER 1985 O
COMMISSION BRIEFINGS SEPT., NOV. 1985 l
COMMISSION DECISION JANUARY 1986 PROPOSED RULE AND DRAFT REGULATORY FEBRllARY 1986 !
GUIDE TO BE PUBLISHED FOR COMMENT :
END OF PUBLIC COMMENT PERIOD MAY 1986 FINAL RULE TO CRGR OCTOBER 1986 FINAL RULE TO COMMISSION JANUARY 1987 FINAL RULE TO BE ISSUED MAY 1987 0 .
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I D
D DRAFT REGULATORY GUIDE ONSITE EMERGENCY AC POWER SYSTEPS
' RELIABILITY PROGRAM TO MAINTAIN EDG RELIABILITY MAXIMUM EDG FAILURE RATE PROCEDURES FOR RESTORING EMERGENCY AC POWER OFFSITE POWER PROCEDURES TO RESTORE OFFSITE POWER AND USE NEARBY OFFSITE POWER SOURCES.
ABILITY TO COPE WITH STATION BLACK 0UT EVALUATION OF- ABILITY TO COPE WITil STATION BLACK 0UT SELECTION OF MINIMUM ACCEPTABLE STATION BLACKOUT DURATION CAPABILITY MODIFICATIONS TO PLANT (IF NECESSARY)
PROCEDURES AND TRAINING O
!I)
PROPOSED RULE ADDITIONAL PARAGRAPH TO APPENDIX A, GDC 17 i 2
i THE REACTOR CORE AND ASSOCIATED COOLANT, CONTROL, AND i PROTECTION SYSTEMS, INCLUDING THE BATTERIES, SHALL PROVIDE SUFFICIENT CAPACITY AND CAPABILITY TO ASSURE THAT THE CORE IS i COOLED AND CONTAINMENT INTEGRITY IS MAINTAINED IN THE EVENT OF A STATION BLACK 0UT FOR A SPECIFIED DURATION, THE FOLLOWING FACTORS SHALL BE CONSIDERED IN SPECIFYING THE STATION BLACK 0UT DURATION: (1) THE REDUNDANCY OF THE ONSITE EMERGENCY AC POWER
([) SOURCES, (2) THE RELIABILITY OF THE ONSITE EMERGENCY AC POWER SOURCES, (3) THE EXPECTED FREQUENCY OF LOSS OF 0FFSITE POWER, AND (4) THE PROBABLE TIME NEEDED TO RESTORE OFFSITE POWER.
4 I
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e ACRS SUBCOMMITTEE ON REACTOR OPERATIONS MEETING JANUARY 7, 1986 !
RANCHO SECO REACTOR TRIP AND UNCONTROLLED l C00LDOWN OCTOBER 2, 1985 UPDATE (S. MINER, NRR) !
REACTOR TRIP FROM 15% POWER DUE TO HIGH PRIMARY SYSTEM PRESSURE REACTOR TRIP CAUSED BY TRIP OF THE MAIN FEED WATER PUMPS UNCONTROLLED C00LDOWN OF 110*F IN 15 MINUTES PRIMARY CAUSE OF C00LD0WN WAS LIFTING OF THE STEAM RELIEF VALVE
~0N ONE OF THE FEEDWATER HEATERS (4TH POINT)
VACUUM LOSS DID NOT INITIATE REACTOR TRIP NOR EFFECT THE RESULTING TRANSIENT MAIN FEED PUMP TRIP (MFP)
CAUSE DEFECTIVE HIGH PRESSURE TRIP SWITCH TRIPPED A PUMP MOST PROBABLE CAUSE OF B PUMP TRIP WAS OPERATOR MANUAL ACTION ,
B MFP AT MINIMUM SPEED
/~' COULD NOT INCREASE SPEED FAST ENOUGH TO ESTABLISH FLOW TO SG T -
AUXILIARY FEED PUMPS (AFW) OPERATING TRIPPED B PUMP TO OPEN AUXILIARY FEEDWATER (AFW VALVES)
CORRECTIVE ACTION
- 1. REPLACED HIGH PRESSURE SWITCH
- 2. ADDED TRIP MONITORING CIRCUITRY
- 3. MODIFIED INSTRUMENTATION SO THAT.AFW VALVES OPEN ON SAME PARAMETER AS AFW PUMPS (LOW MFP DISCHARGE PRESSURE)
UNCONTROLLED C00LDOWN CAUSE STEAM PRESSURE CONTROLLER ON STEAM TO HEATER (PEGGING STEAM) SET CLOSE TO RELIEF SET POINT OF SAFETY VALVE CORRECTIVE ACTION INCREASED SAFETY VALVE SETPOINTS ON HEATERS USING PEGGING STEAM (2ND AND 4TH POINT HEATERS)
- EVALUATION l
LICENSEE CONCLUDED C00LDOWN WAS WITHIN ANALYTICAL LIMITS MEETING
.(]) REQUIREMENT OF 10 CFR 50 APPENDIX G
~ INDEPENDENT NRC EVALUATION CONCLUDED NO ADVERSE AFFECT ON STRUCTURAL INTEGRITY OF THE REACTOR VESSEL i
}.
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i l RANCHO SECO - AFW PUMP FAILURE (UPDATE)
! AFW PUMP THRUST BEARING FAILURE j SLINGER RING INSTALLED IMPROPERLY BEARING REPAIRED WITH SLINGER RINGS PROPERLY INSTALLED ENDURANCE TEST OF REPAIRED PUMP COMPLETED OTHER SAFETY RELATED PUMPS WITH SLINGER RINGS INSPECTED
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I RANCHO SECO REACTOR TRIP DECEMBER 5,1985 AND DECEMBER 26, 1985 i
DECEMBER 5, 1985 REACTOR TRIP PLANT AT 91% POWER
, TRANSFERRING CONTROL FROM MANUAL TO AUTOMATIC MFW FLOW INCREASED I -
RETURN TO MANUAL TO REDUCE MFW FLOW
! B FLOW METER PEN HUNG UP OPERATOR REDUCED FLOW FURTHER HIGH PRESSURE SCRAM SAFETY VALVE ON FEEDWATER HEATER OPENED DUE TO 20% OVERSHOOT OF PEGGING STEAM PRESSURE CONTROLLER MANUALLY SHUT OFF STEAM TO HEATER PLANT STABILIZED WITHOUT EXCESSIVE C00LDOWN OR PRESSURE TRANSIENT SET POINT OF PEGGING STEAM PRESSURE CONTROLLER LOWERED DECEMBER 26, 1985 REACTOR TRIP PLANT AT 76% POWER LUSS OF ICS CAUSED A REACTOR TRIP RCS UNCONTROLLED C00LDOWN OF ABOUT 200*F IN 26 MINUTES IIT AT SITE, FRED HEBDON (AE0D) TEAM LEADER O
- - - - 4
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CRYSTAL RIVER 3 - MFW FAILURE /AFW ACTUATION / REACTOR TRIP November 22.1985 (H. SILVER, NRR) 1 PROBLEM:
o PARTIAL MFW FAILURE, AFW ACTUATION AND REACTOR TRIP SIGNIFICANCE:
o QUESITONS REGARDING PROCEDURES AND TRAINING, POST-TRIP REVIEW, OPERABILITY OF COMPONENTS, UNNECESSARY AFW CHALLENGES CIRCUMSTANCES:
i o PLANT AT 20% POWER, BEING SHUTDOWN TO REPAIR DROPPED ROD o INAPPROPRIATE MFW VALVE MANIPULATION, SLUGGISH VALVE OPERATION CAUSED LOW SG l.EVEL IN SG "A" o AFW ACTUATED PROPERLY, SECURED QUICKLY BY OPERATORS (DIFFICULTY IN CLOSING AFW STEAM ADMISSION VALVE) o LOW SG LEVEL CAUSED REACTOR TRIP ON HIGH PRESSURE o PORV FAILED TO OPEN ON COMMAND; BLOCKED CLOSED. LATER FOUND TO BE FAILED OPEN o
AFTER TRIP, AFW STEAM ADMISSION VALVE OPENED SPURIOUSLY, CAUSING MILD OVERC00 LING EVENT o LATER, EFIC LEVEL TRANSMITTER SENSITIVITY CAUSED SPURIOUS AFW INITIATIONS FOLLOWUP ACTIONS:
PROBLEMS ACTION AFW RELIABILITY o EXCESSIVE CHALLENGES TO AFW MFW RELIABILITY B&W OG EFIC TRANSMITTER SENSITIVITY DESIGN CHANGE O
r
j., , ()
o OPERATOR TRAINING AFD PROCEDURES !
PRCCEDIIRES CHANGE; OPERATOR
- TRAINING MFW OPEPATION SECURING EFIC (TIMING, METHOD)
UNDERSTANDING OF AND CONFIDENCE IN AFW/EFIC (NEED TO SECURE QlIG1Y, METHOD OF SECURING, CLOSING OF STEAM ADMISSION VAI.\O POST TRIP DEVIEW o
EXTENT OF INTER-DISCIPLINARY HIGH-LEVEL PRC REVI&!
, . REVIEW PREVIOUS PRI STARTUP VALVE PROBLEM NRV EQUIFFENT MALRINCTION
- o PORV PILAY CONTACTS - PEPLACED o STEAM ADMISSION VALVE CANF!0T DUPLICATE O o SLLF61SH FFW LOW-LOAD FFW VALW. OPEPATION CONTROL SEIPOINTS - REPAIRED o STARTitP FFW VALVE OPEPATION TIBE AF'D CONTROL PRESSURE
- REPAIRED O
6
i 1
O D. C. COOK UNIT 2 - REACTOR TRIP BREAKER FAILURES
. OC103ER 29, AND NOVEM3 ER 3, 1985 iJPDATE - V. D. Ill0 MAS, IE PROBLEM: UVTA/RTB-A FAILED TO TRIP DURING OCTOBER 29, 1985 ACTUAL SCRAM DEMAND UVTA/RTB-B FAILED UVTA FORCE MARGIN TEST ON NOVEMBER 3, 1985 SIGNIFICANCE: UNKNOWN DEGRADATION / FAILURE MECHANISM FOR NEW UVTA IN WESTINGHOUSE DB-50 RTB DISCUSSION:
IN-PLANT TESTING SHOWED PROBLEM TO BE LOSS OF FORCE IN UVTA
()
- BULLETIN 85-02 ISSUED NOVEMBER 5, 1985, TO REQUIRE SPECIAL TESTS FOR CURRENTLY OPERATING PLANTS, (KEWAUNEE, BEAVER VALLEY 1, AND TURKEY POINT 4) WITHOUT AUTO SHUNT TRIP, 2 TEST FAILURES AT KEWAUNEE; OTHERS SUCCESSFUL FAILURE ANALYSIS TESTING STARTED AT WESTINGHOUSE NOV. 11, 1985 -- VISUAL INSPECTIONS, FORCE MEASUREMENTS, ELECTRICAL TESTS, CYCLIC PERFORMANCE TESTS -- RESULTS NOT IN YET --
NRC/FRC MONITORING LICENSEE MAY DECIDE TO DO SUPPLEMENTAL TESTS -- PERFORMANCE TESTS, DISASSEMBLY AND EXAMINATION IE/ VENDOR BRANCH CONDUCTED SPECIAL INSPECTION OF UVTA MANUFACTURING (DEC. 1983) AND RTB REFURBISHMENT (JULY, 1985)
-IE ISSUED TEMPORARY INSTRUCTIONS TO FACILITATE REGIONAL FOLLOWUP INSPECTIONS IE ISSUED RESPONSE LETTER TO W REGARDING THEIR REVIEW COMMENTS ON IEB 85-02 NRR/ LICENSEE MEETING SCHEDULED FOR 2ND WEEK IN JANUARY TO DISCUSS RESULTS OF FAILURE ANALYSIS TESTING CONDUCTED BY
(]) W/ LICENSEE IN NOVEMBER / DECEMBER 7
FERMI UNIT 2 - EMERGENCY DIESEL GENERATOR BEARING FAILURES s- b (M.D. LYNCH, NRR)
F
.i
- i. PROBLEM CONTINUING DIESEL FAILURES FROM JANUARY 1985 TO DECEMBER 1985 l SIGNIFICANCE RELIABILITY OF ON-SITE POWER
! CIRCUMSTANCES SIMILAR MULTIPLE FAILURES OF DIESELS OVER AN EXTENDED PERIOD OF TIME DIESEL MARCi1 1985 NOVEMBER 1985 11 BRNG FAILURE REPAIRED BRNG FAILURE: REPAIRED -
- 12. BRNG FAILURE: REPAIRED
- BRNG FAILURE REPAIRED O 13 INSPECTION ACCEPTED BRNG FAILURE: REPAIRED
- 14 INSPECTION; ACCEPTED BRNG FAILURE REPA! RED' .
'CRANKLINE REPLACED FOLLOWUP 2 REVIEW TEAMS CURRENTLY INVESTIGATING (R-III, NRR, LICENSEE /FAA)
FRANKLIN INSTITUTE EXAMINING BEARINGS APPARENT CAUSE MAY BE DUE TO INADEQUATE LUBRICATION AND METHOD OF " BREAK-IN" LICENSEE TEST PROGRAM ON EDG N0, 13 SCHEDULED REPAIRS TO BE COMPLETED BY END OF THE YEAR 50.54(F) LETTER BEING ISSUED REQUESTING ADDITIONAL INFORMATION _
O 2
NORTH ANNA UNIT 1 - EMERGENCY DIESEL GENERATOR DEFECTIVE PARTS
() DECEMBER 12,1985 (M. D.1 YNc4 , NRR)
PROBLEM: NUTS THAT SECURE BEARING CAP TO CONNECTING R0D ARE NOT " SQUARE" SIGNIFICANCE:
POTENTIAL COMMON MODE FAILURE OF EDGs GENERIC APPLICABILITY, COLT /FAIRBANKS MORSE ENGINES DISCUSSION:
THREAD-PITCH NOT PERPENDICULAR TO NUT FACES: INDUCING STRESSES BEYOND DESIGN LIMITS, NUT FAILURE DISCOVERED BY FACTORY ASSEMBLER ON NEW ENGINE BATCH PROBLEM (SUB-VENDOR, " QUALITY SCREW CO,")
10 CFR 21 LETTER, NOVEMBER 26, 1985; BELIEVED TO INVOLVE ONLY ,
SPARE PARTS; COPIES TO CALVERT CLIFFS, NORTH ANNA, LIMERICK, O FERMI
~
INSPECTION OF EDG "1J" AT NORTH ANNA FOUND DEFECTIVE NUTS, PRIOR TO REFUELING RESTART OF PLANT AFFECTED LICENSEES BEING ADVISED BY VENDOR IE/ VENDOR PROGRAM BRANCH FOLLOWING UP; NRR/0 RAS BEING KEPT INFORMED ee O
v
CATAWBA UNIT 2 - TDI EMERGENCY DIESEL GENERATOR MAIN BEARING FAILURES NOVEMBER 20 AND DECEMBER 5,1985, (M D. LYNCH. NRR)
PROBLEM:
REPEATED FAILURES OF EDG 2B MAIN BEARING #7 SAFETY SIGNIFICANCE:
LOSS OF ONSITE EMERGENCY POWER PELIABILITY POTENTIAL GENERIC APPLICABILITY TO FACILITIES WITH SIMILAR V-16 ENGINE (CATAWBA 1, GRAND GULF, PERRY, MIDLAND, V0GTLE, WNP-1, COMANCHE PEAK, HARRIS)
SEQUENCE OF EVENTS:
UNIT IN PRE 0PERATIONAL TESTING OCTOBER 1985-2B ENGINE TEAR-DOWN INSPECTION: 6 0UT OF 10 BEARINGS INSPECTED. # 7 NOT INSPECTED NOVEMBER 20-FAILURE OF BEARING # 7 AFTER 5 HOUR OPERATION; POSTULATED CAUSE WAS INADEQUATELY SUPPORTED BEARING FOLLOWING FAILURE, 7 OUT OF 10 BEARINGS INSPECTED. #1, 2, O AND 4 NOT INSPECTED, 5 0UT OF 7 REPLACED ALTHOUGH ONLY LIGHTLY SCORED, DECEMBER 5-FAILURE OF BEARING #7, TEST STOPPED AFTER 4 MINUTES FAILURE MODE SIMILAR FOR BOTH INCIDENTS. BEARING HAD CRACK AT MINIMUM WALL SECTION FOLLOW-UP:
DETAILED FAILURE ANALYSIS AND DIMENSIONAL CHECK IS IN PROGRESS LICENSEE CONSULTING WITH TDI CAUSE OF FAILURE HAS NOT YET BEEN IDENTIFIED POSSIBLE DELAY IN CATAWBA 2 FUEL LOAD DATE STAFF MONITORING LICENSEE'S EFFORT COMMISSION INFORMED VIA BN85-092, ISSUED 12/12/85 t
Se O
. /
MCGUIRE UNITS 1 AND 2 - DUAL UNIT TRIP ON LOSS OF INSTRUMENT AIR NOVEMBER 2, 1985 (J. GilTTER, IE)
[)
PROBLEM: LOSS OF COMMON INSTRUMENT AIR SYSTEM CAUSED BOTH UNITS 1 AND 2 TO TRIP SAFETY SIGNIFICANCE: NON-SAFETY GRADE SYSTEM FAILURE RESULTS IN CHALLENGE TO SAFETY SYSTEMS - TWO UNITS AFFECTED BY SINGLE FAILURE DISCUSSION:
A SECTION OF BRAIDED, FLEXIBLE PIPE ON THE DISCHARGE OF THE "B" INSTRUMENT AIR COMPRESSOR RUPTURED AT A WELDED SEAM CAUSING THE INST. AIR SYSTEM TO DEPRESSURIZE AIR SYSTEM COMMON TO BOTH UNITS BOTH UNITS TRIP FROM 100% POWER ON LO LO STEAM GENERATOR
(} LEVEL CAUSED BY CLOSURE OF THE MAIN FEEDWATER FLOW CONTROL VALVES ON LOSS OF AIR PRESSURE AUX. FEED FLOW CONTROL VALVES GO OPEN ON LOSS OF AIR RESULTING IN EXCESS AFW FLOW AIR RESTORED IN ABOUT EIGHT MINUTES UNIT 1 DEPRESSURIZED TO St INITIATION POINT (1845 PSIG)
(INJECTION FOR ABOUT 10 MINUTES)
UNIT 2 OPERATORS RECOGNIZED UNIT 1 PROBLEM AND TRIPPED TWO REACTOR COOLANT PUMPS TO SLOW COOLDOWN CAUSED BY PRESSURIZER SPRAY VALVE LEAKAGE. NO SI OCCURRED ALL OTHER PLANT SYSTEMS PERFORMED AS EXPECTED FOR THIS TRANSIENT
, (")h
\_ -
UNIT 1 COOLDOWN WAS 86*; UNIT 2 COOLDOWN WAS 74*
//
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FOLLOWUP:
PRZR HEATER GROUP B ON UNIT 1 WAS REPAIRED THE FLEXIBLE PIPE ON THE INSTRUMENT AIR COMPRESSORS WAS REPLACED THE USE OF THE BRAIDED, FLEXIBLE PIPE ON THE INSTRUMENT AIR SYSTEM WILL BE REVIEWED TO DETERMINE IF OTHER REPLACEMENT OR MODIFICATIONS ARE NECESSARY TO INCREASE RELIABILITY CHECK VALVES WILL BE INSTALLED ON THE DISCHARGE OF THE THREE REClPROCATING INSTRUMENT AIR COMPRESSORS FLEXIBLE PIPE APPLICATIONS IN OTHER PLANT SYSTEMS AND AT ALL DUKE POWER NUCLEAR STATIONS WILL BE REVIEWED
'V(~')
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(n_) ST. LUCIE UNIT 1 - UGS LIFTING RIG FAILURE NOVEMBER 6, 1985 (S. LONG, IE)
PROBLEM: WHILE REMOVING THE UPPER GUIDE STRUCTURE (UGS) 1 OF 3 BOLTS CONNECTING THE UGS TO THE LIFTING RIG FAILED WITH THE UGS STILL OVER THE CORE SIGNIFICANCE: THE 50 TON LOAD COULD FALL BACK INTO REACTOR 1 VESSEL, POSSIBLY CONTACTING AND DAMAGING FUEL, RESULTING IN RELEASE OF RADIOACTIVE GASES TO THE CONTAINMENT CIRCUMSTANCES:
WHILE LIFTING THE UGS, LIFT WAS STOPPED WHEN RlG WAS SEEN TO TI LT AFTER IT WAS RAISED 8 FEET.
1 OF 3 BOLTS ATTACHING RlG TO UGS HAD DISENGAGED. RlG CANTED
~6" UP AND UGS CANTED ~6" DOWN ATTEMPT WAS MADE TO LOWER UGS TO INSTALLED POSITION, BUT LOAD CELLS INDICATED BINDING
() -
LICENSEE DECLARED AN UNUSUAL EVENT, ENHANCED CONTAINMENT INTEGRITY AND IMPLEMENTED PROCEDURES TO MONITOR LOAD STABILITY SECONDARY LIFTING RIG WAS DESIGNED, TESTED AND INSTALLED ASSEMBLY WAS JACKED LEVEL AND THEN MOVED TO ITS NORMAL PARKING POSITION IN REFUELING POOL ON 11/9 FINDINGS:
INSPECTION REVEALED THAT FAILED BOLT WAS ONLY INSERTED ABOUT 1/2 TURN, AND STRIPPED DURING LIFT CE PROCEDURES FOR RlG ATTACHMENT INCLUDE VERIFICATION OF THREAD ENGAGEMENT; THIS WAS OMITTED FROM LICENSEE'S PROCEDURES DAMAGE: LIFT RIG AND ONE VESSEL GUIDE PIN WERE BENT.
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- FOLLO T :
LICENSEE RETURNED UGS TO INSTALLED POSITION USING LONG ATTACHMENT BOLTS WITH HEADS THAT BEAR ON RIG SURFACES ABOVE WATEP. LEVEL LICENSEL' IS REVIEWING OTHER LIFT PROCEDURES TO ENSURE PROPER VERIFICATION OF BOLT THREAD ENGAGEMENT REVIEW OF USI A36 PHASE 2 ANALYSIS FOR WATERFORD INDICATES THAT FUEL WOULD NOT HAVE BEEN SIGNIFICANTLY DAMAGED BY DROP IE PREPARING INFORMATION NOTICE t
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1 0 sus 0uEsaNuA cNiTS i AND 2 - LOSS OF Tiii TaANSF0 amen DECEMBER 2, 1985 (M. CAMPAGNONE, NRR) l PROBLEM:
- LOSS OF Till TRANSFORMER CAUSED INTERRUPTION OF A, C,
! POWER (C CHANNEL IN BOTH UNITS) TO INSTRUMENT AND CONTROL 4
PANELS IN BOTH UNITS 1 AND 2 i
i -
POWER INTERRUPTION CAUSED FEEDWATER PUMP CONTROLLERS TO LOCK-UP l :
SIGNIFICANCE:
A SINGLE LOSS OF POWER CAN CAUSE A FW TRANSIENT IN BOTH I
UNITS AND CAUSE EACH UNIT TO SCRAM i
_O CIRCUMSTANCES:
I -
SUDDEN PRESSURE RELAY TRIPPED THE Till TRANSFORMER LOADS AUTOMATICALLY TRANSFERRED TO THE T211 TRANSFORMER MOMENTARY INTERRUPTION OF A.C. POWER TO CONTROL AND INSTRUMENT PANELS CAUSES FW CONTROLLERS TO LOCK-UP CAUSING THE THREE l l VARIABLE SPEED, 33% CAPACITY FW PUMPS IN EACH PLANT i TO FAIL "AS IS" UNIT 1 OPERATORS FAILED TO RESET SWITCHES WHICH WOULD ALLOW THE
! MANUAL CONTROL OF THE FW CONTROLLERS THIS RESULTED IN A STEAM-FEED MISMATCH WHICH CAUSED Rx O
WATER LEVEL TO INCREASE TO LEVEL 8 (+54") TRIPPING THE
- UNIT ON HIGH Rx WATER LEVEL l
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_2-O UNIT 2 OPERATORS RESET SWITCHES TO GAIN MANUAL CONTROL OF FW
, CONTROLLERS -
i THE "A" FW PUMP CONTROL LOGIC HAD A ERROR WHICH UPON RESETTING SWITCHES CAUSED THE "A" FW PUMP TO WIND DOWN TO j ZERO FLOW
, THE OPERATORS TRIED TO MAKE-UP THE FLOW WITH THE "B" AND i
"C" FW PUMPS BUT THE LEVEL HAD ALREADY DROPPED TO LEVEL 3 p -
(+13") CAUSING A REACTOR SCRAM ON LOW Rx WATER LEVEL i
LEVEL DECREASED TO -311" .
Q -
RCIC AUTO INITIATED AT -30" MSIV'S CLOSED l -
HPCI MANUALLY INITIATED i FOLLOW-UP i -
LICENSEE HAS MODIFIED LOAD LINE UP SO THAT FW CONTROL INSTRUMENTATION WILL BE POWERED FROM VITAL A.C. POWER.
THIS PROVIDES AN UNINTERRUPTED SOURCE OF POWER 1
LICENSEE HAS BEEN REQUESTED TO IDENTIFY OTHER INSTRUMENTA-TION ON Ist PANELS, AND INVESTIGATE THE RESULTS OF A SIMILAR i SCENARIO NOTE: A SIMILAR SCENARIO WAS ANALYZED AND DISCUSSED IN SSER 7
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AND WAS DETERMINED TO BE BOUNDED BY CH 15 ANALYSIS AND THEREFORE ACCEPTABLE,
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! DECEMBER 12, 1985 (RABl SINGH, IE)
DESIGN FEATURES:
138 KV SWITCHYARD - PRIMARY PREFERRED OFFSITE POWER SOURCE 6.9 KV FROM 138 KV SUBSTATION OR GAS TURBINES -
SECONDARY SOURCE 9
SECONDARY SOURCE REQUIRES MANUAL ACTION 3 EDGS t~w -
EVENT DESCRIPTION:
O.
UNIT IN HOT SHUTDOWN FOLLOWING A REACTOR TRIP APPROX. -
1 1/2 HRS EARLIER ON A LOSS OF FLOW SIGNAL PERSONNEL BUMPED INTO A RELAY PANEL IN THE CONTROL ROOM DURING RELAY CHECKING RELAY CHATTER CAUSED BOTH 6.9 KV BREAKERS (ST 5 S ST 6)
TO OPEN AND LOSS OF OFFSITE POWER OCCURRED
- EDGS STARTED AND PICKED UP LOADS RCPS LOST. ENTERED NATURAL CIRCULATION OFFSITE POWER RESTORED IN 15-20 MINS 1
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t V WATERFORD 3 LOSS OF OFFSITE POWER, DECEMBER 12, 1985 (RABI SINGH, IE) ,
DESIGN FEATURES:
! TWO OFFSITE POWER SUPPLIES FROM 230 KV SWITCHYARD 2 * !
TWO STARTUP TRANSFORMERS i
SWITCHYARD CONNECTED TO UNITS 1 & 2 AND OTHER SOURCES EVENT DESCRIPTION:
l
~
UNIT 3 IN COLD SHUTDOWN ,
LIGHTNING STRUCK THE B PHASE OF WATERFORD-LITTLE GYPSY 1
, LINE FAULT CLEARED BY NORMAL RELAY ACTION AND BREAKER OPERATION j
- (3212, 3215, 7102 AND 7106)
AT THE SAME TIME, UNIT 1 MAIN TRANSFORMER WENT OFF LINE DUE TO A PROBLEM WITH THE SUDDEN PRESSURE RELAY ;
~
! 30 SECONDS LATER, 3212 AND 710). AUTO CLOSED.
2 A FEW MINUTES LATER, DISPATCHER TRIED TO CLOSE 7106 WHICH .
FAULTED DUE TO FAILED BUSHING.
FAULT CLEARED BY NORMAL RELAY ACTION AND BREAKER OPERATION (7102, 7106, 7112, 3212, 4701, 4746) [;
l THIS FAULT RESULTED IN OPENING OF WATERFORD 3 B LINE l BREAKERS (7182, 7186) DUE TO PHASE COMPARISON RELAYING ,
4
. (~T U
30 SECONDS LATER, 3212 AUTO-CLOSED AND FAULTED 7106 I BUSHING RE-ENERGl2ED. 7112 OPENED TO CLEAR THE FAULT THIS FAULT ALSO CAUSED OPENING OF WATERFORD 3 A LINE BREAKERS (7172, 7176) DUE TO PHASE COMPARISON RELAYlNG 1
TOTAL LOSS OF OFFSITE POWER OCCURRED A FEW MINUTES LATER, DISPATCHER CLOSED 7102 AND 7112 WHICH ENERGl2ED THE 7106 FAULTED BUSHING MISOPERATION OF RELAYING CAUSED RACELAND LINE TO SWITCHYARD TO BE LOST. RACELAND LINE RESTORED DURING RESTORATION, 7112 WAS CLOSED AGAIN WHICH
{} RESULTED IN LOSS OF 500 KV LINE TO SWITCHYARD FOR 3 MINS.
- FOLLOWING THE LOSS OF OFFSITE POWER, BOTH EDGS STARTED AND PICKED UP THE LOAD SHUTDOWN COOLING LOST FOR 5 MINS.
OFFSITE POWER TO STARTUP TRANSFORMERS RESTORED IN APPROX. ;
40 MINS. ;
FEEDER BREAKERS TO START-UP TRANSFORMERS HAD OPENED DUE i TO PHASE COMPARISON RELAYS BEING SET TOO LOW FOR PLANT CONDITIONS i RELAY SETTINGS RAISED TO CORRECT THE PROBLEM OY
RIVER BEND LOSS OF OFFSITE POWER, JANUARY 1, 1986 (RABI SINGH, IE)
REACTOR IN HOT SHUTDOWN LOST ALL OFFSITE POWER ALL EDGS STARTED AND PICKUP UP THE LOAD OFFSITE POWER RESTORED AFTER 1 HR. 15 MIN.
lNVESTIGATION REVEALED THAT FEEDER BREAKERS TO BOTH START UP TRANSFORMERS OPENED AS A RESULT OF RADIO BLITZ A SECURITY GUARD USED HIS PADIO INSIDE A BUILDING WITH FIBER OPTICS (TONE SYSTEM)
TONE SYSTEM, USED FOR SEPARATING OFFSITE POWER CONTROL CABLES,
. PICKED UP THE BLITZ AND CAUSED THE LOSS OF ONE START-UP TRANSFORMER THE FEEDER BREAKERS CAN BE ONLY LOCALLY RESET AND WERE NOT RESET IN THE MEAN TIME, THE GUARD WENT TO THE SAME BUILDING AGAIN AND THIS TIME THE REMAINING START-UP TRANSFORMER WAS LOST O
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1111CH UNIT 1 - FLOODING 0F SAFETY-RELATED AREAS O DECEf!BER 2L 1985 (G. P,IVENBARK, f!RR) o PROElFM RHR PUt1P ROOM ACCIDENTALLY FLOODED DURING MAlllT OTHER R00flS CONTAINIflG SAFETY-RELATED EQUIPMENT SU QUENTLY FLOODED TO LOW LEVELS !
O SIGNIFICANCE P00R IMIflTENANCE PROCEDURE O '
CIRCUMSTAllCES UNIT TOTALLY DEFUELED MAINTENANCE BEING PERFORf1ED ON ISOLATIO!! VALVE IN RilR TORUS SUCTIO!1 LINE.
SINGLE AIR-0PERATED VALVE RELIED ON FOR ISOLATION 0F TORUS LOSS OF ELECTRIC POWER TO ACTUATOR SOLEl!0ID DUE TO O -
DIESEL TESTING RESULTED Ifl 0PEllING ISOLATION VALVE WATER FLOWED BY GRAVITY THROUGil VALVE 0!) HHICll ilAINTENANCE WAS BEING PERFORMED RHR ROOM FLOODED 114 FEET DEEP SUBSEQUENT DRAltlING OF RHR R00fl RESULTED IN HATER ,
BEING INTRODUCED TO OTHER SAFETY EQUIPMEllT R00!!S 0 FOLLOH-UP REGION II SENT GROUP TO SITE TO REVIEN OPERATIONAL, MAINTEllANCE AND EQUIPi1ENT RESTORATI0tl ASPECTS LICENSEE DEVELOPING flAINTEllANCE AND TEST CLEARANCE PROCEDURES AND RELATED OPERATOR TRAlflING LICENSEE EVALUATING EACH E0VIPi1ENT ITEM THAT HAS WETTED FOR RESTORATIO!! OR REPLACEME!1T O
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'O Event Date Event Facts :
January 1985 1. Extensive damage to No.11 Diesel Generator.
- 2. Damage to No.12 Diesel Generator.
l
- 3. No damage observed on Diesel Generators No.13 i
l and No.14.
I ;
/i November 13,1985 1. Extensive damage to No.11 Diesel Generator.
- 2. Extensive damage to No.13 Diesel Generator.
- 3. No damage observed on Diesel Generators No.12 and No.14, although scoring was noted on ;
O No.14 bearings.
December 23,1985 1. Damage to bearing on No.11 Diesel Generator j after 16 hours1.851852e-4 days <br />0.00444 hours <br />2.645503e-5 weeks <br />6.088e-6 months <br /> of run time.
, 2. Low lube oil viscosity on Diesel Generators (I No.12 and No.14.
! December.27,1985 1. Damage to additional bearing on No.11 Diesel Generator after approximately one hour additional
,i run time.
t;
- 2. Three bearings on Diesel Generator 13 showed l'O evidence of metal pickup. Origin of metal unknown.
.-_ ._._....__._.-._ ,_.__ _.. _ ... .___ m .______,, .. , . , _ . . _ _ . _ , _ _ , . .
p FERMI 2 DIESEL GENERATOR PROBLEMS
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- UCENSEE'S CORRECTIVE ACTIONS TAKEN TO DATE ,;
Event Date Event Facts l January 1985 a. Failures attributed to lack of pre-lubrication.
- i
- b. Manual pre-lubrication procedure implemented,
- c. Lube oil monitoring program implemented.
November 1985 c. Failure attributed to inadequate engine break in.
- b. Test program implemented to precondition (break in)
O .
engine.
- December 1985 a. Cause(s) unknown.
- b. Problem on Diesel Generator Generator No.13 4
observed after test / break in program completed.
- NRC ACTION i
NRC assembled a team of individuals from l&E, NRR and contractors in l l January and November to review and evaluate the observed Diesel Generator l
- problems. Currently, NRC is waiting for the licensee's " Plan" for 0i evaluating the most.recent failures. Contractor's evaluations are ongoing.
l
.e v
Peach Bottom 2 and 3 - Resisidual Heat Removal Pump Wear Ring Failures January 7, 1986 (T. Johnson, R. Gallo, Region I)
Problem Failure of pump impeller lower wear ring with subsequent pump performance degradation or possible damage to pump.
. Potential loss of low pressure coolant injection during design basis LOCA.
Potential loss of long term shutdown decay heat removal capability.
Equipment Pump Model: Bingham 18x24x28 CVIC (centrifugal, vertical, single stage)
I Motor:~GE, 2000HP, 3 Phase 4 RHR pumps per Unit - Technical Specification flow 10,900 gpm.
Circumstances Peach Bottom 3 - refueling outage cornenced July,1985.
-- On November 2, 1985, a fire occurred in 3C RHR pump motor.
Wear ring problem first discovered during inspection of 3C RHR pump - wear ring off impeller and cracked.
On November 16, 1985, similar wear ring problems discovered during inspection of 3A RHR pump.
On November 26, 1985, similar wear ring problems discovered during inspection of 3B and 3D RHR pumps (30 had cracked upper wearring).
All 4 Unit 3 RHR pumps have been repaired with new impe11ers and wear rings, tested and are currently operable.
Peach Bottom 2 - maintenance outage from November 29, 1985 to December 24, 1985.
On December 3, 1985, inspected 2A and 2C RHR pumps. Wear rings were attached to impeller (2A RHR pump lower wear ring had p]
L surface cracks).
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2A and 2C RHR pumps repaired with new impellers and wear rings.
On December 21, 1985, 2D RHR pump motor overcurrent alarmed.
Inspected 20 RHR. pump and found lower wear ring cracked and off.
2D RHR pump repaired with old impeller and new wear rings.
2A, 2C, 20 RHR pumps tested satisfactorily after repairs.
Unit 2 currently operating at power.
Historical Information - in February, 1982, 2A RHR pump lower wear ring failed.
Wear Ring Failure
Conclusions:
Prior indication of impending failure.
Licensee performed metallurgical analysis of wear ring failure.
The wear rings failed by intergranular stress-associated corrosion cracking (IGSCC) which propagated from numerous surface indications.
Ih --
Material is 410 stainless steel.
Follow Up:
Peach Bottom Units 2 and 3 repaired 7 of 8 RHR pumps. Eighth RHR pump (28) being tested weekly and will be inspected within 120 days.
Licensee is performing acoustic monitoring of RHR pumps in addition to normal inservice testing.
IE is preparing Information Notice, and determining if there are similar pumps / motors in any other facilities.
NRR has the . lead for evaluating and dispositioning IGSCC issues.
Vendor - attempting to determine cause of problem.
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\s Peach Bottom 2 and 3 - Resisidual Heat Removal Pump Wear Ring Failures January 7, 1986 (T. Johnson, R. Gallo, Region I)
Problem Failure of pump impeller lower wear ring with subsequent pump performance degradation or possible damage to pump.
Potential loss of low pressure coolant injection during design basis LOCA.
Potential loss of long term shutdown decay heat removal capability.
Equipment Pump Model: Bingham 18x24x28 CVIC (centrifugal, vertical, single stage)
Motor: GE, 2000HP, 3 Phase 4 RHR pumps per Unit - Technical Specification flow 10,900 gpm.
n) t Circumstances Peach Bottom 3 - refueling outage commenced July, 1985.
-- On November 2,1985, a fire occurred in 3C RHR pump motor.
Wear ring problem first discovered during inspection of 3C RHR pump - wear ring off impeller and cracked.
On November 16, 1985, similar wear ring problems discovered during inspection of 3A RHR pump.
On November 26, 1985, similar wear ring problems discovered during inspection of 3B and 3D RHR pumps (3D had cracked upper wearring).
All 4 Unit 3 RHR pumps have been repaired with new impellers and wear rings, tested and are currently operable.
Peach Bottom 2 - maintenance outage from November 29, 1985 to December 24, 1985.
On December 3, 1985, inspected 2A and 2C RHR pumps. Wear rings were attached to impeller (2A RHR pump lower wear ring had surface cracks).
. 1 2
qq G
2A and 2C RHR pumps repaired with new impe11ers and wear rings.
On December 21, 1935, 20 RHR pump motor overcurrent alarmed.
Inspected 2D RHR pump and found lower wear ring cracked and off.
20 RHR pump repaired with old impeller and new wear rings.
2A, 2C, 20 RHR pumps tested satisfactorily after repairs.
Unit 2 currently operating at power.
Historical Information - in February, 1982, 2A RHR pump lower wear ring failed.
Wear Ring Failure
Conclusions:
Prior indication of impending failure.
Licensee performed metallurgical analysis of wear ring failure.
The wear rings failed by intergranular stress-associated corrosion cracking (IGSCC) which propagated from numerous surface indications.
O --
sateriai is 410 stainies, steei.
Follow Up:
Peach Bottom Units 2 and 3 repaired 7 of 8 RHR pumps. Eighth RHR pump (28) being tested weekly and will be inspected withii 120 days.
Licensee is performing acoustic monitoring of RHR pumps in addition to normal inservice testing.
IE is preparing Information Notice, and determining if there are similar pumps / motors in any other facilities.
NRR has the lead for evaluating and dispositioning 1050C issues.
Vendor - attempting to determine cause of problem.
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- og TED STATES 4
/g,a nag,, 'A NUCLEAR MEGULATORY cOMMisslON )
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789 ROOstVELT RO AD eLa= eLLvw. eLuwOis som
....+ ,
DEC 1 9 ne3 Docket No. 50-315 l Docket No. 50-316
- ' American Electric Power Service !
Corporation '
. 1 Riverside Plaza 1
Columbus, OH 43216 Centicecr.:
This refers to the special safety inspection e.onducted by the NRC Augmented Incident Response Team under W. L. Forney and C. W. Hehl of this office on October 29, 1985 through November 8, 1985 relating to the failure of a Unit 2 reactor trip breaker to actuate during a Unit trip on October 29, 1985. This refers also to the meetings and discussions of findings with M. P. Alexich and W. G. Smith, Jr. , and others of your staff during the course of and at the
~
\ conclusion of the inspection.
The enclosed copy of the Augmented Incident Response Team report identifies areas examined during the inspection. Within these areas, the inspection
, consisted of a selective examination of procedures and representative records, observations, and interviews with personnel.
{
No violations of NRC requirements were identified during the, course'of this inspection.
In accordance with 10 CFR 2.790(a), a copy of this letter and the enclosure (s) will be placed in the NRC Public Document Room.
We will gladly discuss any questions you have concerning this inspection.
Sincerely,
&.4 Yc'J_E2L C. E. Morelius, Director DivisionofReactorProjects
Enclosure:
Augmented Incident Response Team Report:
No. 50-315/85035;
! O, No. 50-316/85035
- See Attached Distribution
'O american giectric power Service Corporation 2 DEC 19 m Distribution Corporation cc w/ enclosure:
W. G. Smith, Jr., Plant Manager
. DCS/RSB (RIDS)
Licensing Fee Management Branch Resident Inspector, RIII Ronald Callen, Michigan Public Service Commission EIS Coordinator, USEPA Region 5 Office Nuclear Facilities and Environmental Monitoring Section O
s O
-. . _ , _ . . . , _ _ _ . , _ - . _ . . . . _ . ~ . _ _ _ _ _ _ . . . _ . _ . . . . . , _ _ _ _ _ _ _ . . _ - - , _ _ - , _ . _ . . - _ , , _ _ . _ - . _ _ , , , _ _ . - . . . . - -
- .. _- . = _ - - .- . . - . - - - . - . . - - . - - . . ... .- -
.h U. S. NUCLEAR REGULATORY COMMISSION AUGMENTED INCIDENT RESPONSE TEAM Reports No. 50-315/85035; 50-316/85035 :
Docket Nos. 50-315; 50-316 Licenses No. DPR-58; DPR-74 i I
Licensee: American Electric Power Service Corporation Indiana and Michigan Electric Company 1 Riverside Plaza Columbus. OH 43216 Facility Name: Donald C. Cook Nuclear Power Plant, Units 1 and 2 i
Inspection At: Donald C. Cook Site, Bridgman, MI Inspect'c;i Conducted: October 29, 1985 through November 8, 1985 Team Members: W. L. Forney, Chief C. W. Hehl, Chief Section 1A, DRP-RIII Section 2A, DRP-RIII O J. T. Beard D. L. Wigginton
~V Operating Reactor LicensingProject .
Assessment Branch, NRR Manager, NRR V. D. Thomas G. J. Toman, Consultant Engineering / Generic Franklin Research Center ,
Communications,IE:HQ ,
I B. L. Jorgensen J. H. Neisler !
Senior Resident Inspector, Reactor Inspector, ,
D.C. Cook Region III J. K. Heller T. E. Taylor Reside n Inspector, Reactor Inspector, D.C. Cook Region III C. L. Wolfsen E. R. Swanson i Inspector, Senior Resident Inspector D.C. Cook Palisades
]
Approved By:
Mrub'
.' . Morelius, Director i2[#f/F O DivisionofReactorProjects Region III Date a
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- / ' ' '
TABLE OF CONTENTS d
page
- 1. General Discussions ...................................... 3
- 2. Reactor Trip Review
- a. Sequence of Events .................................. 4
- b. Plant. Parameter Review ............................. 5
- c. Operator Actions ................................... 6
- d. Source and Promulgation of Trip Signal ............. 6
- 3. ' Reactor Trip Breaker Evaluation
- a. Breaker History .................................... 7
- b. Breaker Failure Investigation ....................... 10
, 4. Confirmato'ry Action Letter .............................. 13
- 5. Persons contacted ....................................... 15 x
- 6. Open Items .............................................. 15
- 7. Unresolved Item ......................................... 15
- 8. Additional NRC Actions .................................. 15
- 9. Conclusion .............................................. 16 O
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- 1. General Discussions I i On October 29, 1985 the Donald C. Cook Unit 2 plant was operating at !
approximately 80 percent of full power, having just stabilized at that l level following a gradual escalation from 50 percent. The Unit had been l in service for about a week, following an extended outage begun in mid-July j
1985 to identify and repair leaking steam generator tubes. The bulk of i this previous operating week had beta spent with the plant at 30 percent i i
power, while steam generator chemistry was adjusted within specifications ,
1 and a boric acid chemical flushing program of the steam generator secondary I side was performed. Unit 2 steam equivalent to about 1.5 percent power I was being utilized for Unit I system testing. Repairs to a containment i i radiation monitoring instrument (ERS-2300) were in progress, as was a L
! test of the steam generator level set II mismatch portion of the reactor protection system.
l At 1:58 p.m. EDT the reactor tripped, from an indicated loss of reactor l 4
coolant flow on loop "B". No such loss of flow was apparent in the main -
t control room, nor were any activities known to be in progress which might ;
be expected to affect either reactor coolant finw the reactor coolant l l
pumps, or the instrumentation for monitoring these items, i The operators commenced post-trip recovery, stabilizing the primary and l secondary plants. A few minutes into the recovery, the reactor operator l
observed that one of the two reactor trip breakers (RTB "A") had not
- n opened. Further, the anticipated motor operated main feedwater 4
(_) isolation valve closure from reactor trip coincident with low average ;
i primary coolant temperature had not occurred for two of four main feed lines. However, since the feedwater regulating valves had closed in i response to the feedwater isolation signal, the failure of the two main feedwater isolation valves to automatically close did not pose any
- operational concerns. ;
The licensee notified the Nuclear' Regulatory Commission, pursuant to ,
l 10 CFR 50.72 of the RTB failure and the apparent partial feedwater l isolationfallure. The root cause of the reactor trip was as-yet l unidentified at the time of this notification. Due to the potential
- significance of the RTB failure the NRC conducted several telephone j discussions with licensee management concerning the necessity for
- preservation of evidence pending a thorough, disciplined investigation
- ' into the unanswered questions surrounding this event. Following these i
discussions on October 29, 1985, the NRC dispatched to the site an i Augmented Incident Response Team (AIRT). The following day, October 30, t
1985, a Confirmatory Action Letter was sent to the licensee detailing certain commitments made by licensee management during the above -
! telephone discussions. ;
This report details the activities of the AIRT, the licensee and their !
- respective consultants in gathering information for developing conclusions .
1 concerning the cause and course of the automatic reactor trip, the actions
- of the plant operators during this event, the cause of the RTB failure, t i
and associated Confirmatory Action Letter activities.
i l
i i
! 3 f i
- 2. Reactor Trip Review
- a. Sequence of Events The following edited sequence of events was derived by review of
- the Plant Computer (Prodac 250) and Operational Sequence Monitor (OSM) output information on binary parameters (components on/off, open/ closed,etc.). Detailed evaluation of the Prodac 250 and the OSM outputs establish the following composite time-line.
0-100 msec turbine stop valve "A" shows closed reactor coolant pump No. 22 breaker shows open reactor coolant low flow above 30%-TRIP SIGNAL reactor coolant pump bus under frequency (first of four repetitions) reactor coolant pump No. 22 breaker shows closed reactor coolant pump No. 22 breaker shows open reactor coolant low flow above 30%-TRIP SIGNAL No. 22 breaker shows closed reactor stop turbine coolant pump'A" shows open valve 100 msec reactor trip breaker (RTB) "B" trips 300-500 msec reactor trip turbine trip and P7 left circuit turbine trip actuated ower range negative rate trip-reactor trip p' West" and " East" sain feedpump turbine trips right circuit turbine trip actuated 556 msec RTB undervoltage, "A" de-energized 565 msec RTB undervoltage, "B" de-energized 0.6 sec-1 sec generator motoring indicated turbine stop valves A, D, B and C show closed 3.15 see turbine trip - reactor trip 4-5 sec loops 1 and 3 feedwater flow Inw mismatch reactor trip 5.5 - 6.2 sec all four steam generator lo-lo level trips 6.5 sec loop 2 feedwater flow low mismatch reactor trip 29.7 sec unit differential - main generator trip Discrepancies or peculiarities noted in review of the sequence of '
events (binary) items included the following:
(1) Although recorded by the P250, the OSM failed to record the O e eected e wer r 0 a a tiv r te trip sinaai f iiowiaa the 4
e
actual reactor trip. Subsequent investigation of this item identified a defective OSM circuit " card". The defective circuit card was replaced.
(2) Despite the Prodac 250 and OSM outputs, no actual low flow or reactor coolant pump No. 22 breaker "open" condition occurred.
The spurious solid state protection system (SSPS) input signals to this effect were traced to a momentary voltage reduction on the power source carrying the relays for these actuations.
(This is discussed further in Paragraph 2.d). The early (first 100 msec) turbine stop valve " closed" indication and RCP bus under frequency indications are also attributed to this momentary voltage reduction.
- 3) The RT8 undervoltage (breakers A and 8 coils de-energized) indications came in near the end of the 200-600 msec range observed in previous trip reviews, but both came in only a few msec apart.
- b. Plant Parameter Review The following information was derived by review of selected strip charts and the output of the Prodac 250 computer monitor concerning analog data and major plant system parameters.
A Reactor coolant system temperatures, pressurizer pressure and V pressurizer level dropped substantially post-trip. Temperature went as low as 510 degrees F, pressurizer level went below the setpoint (17%) for heater trip and the pressurizer heaters automatically e secured; and pressure dropped from about 2220 to about 1980 psig.
All of these parameters were affected by the relatively low decay heat in the reactor core, the continued excess heat removal occasioned by the supply of steam to Unit 1 via the auxiliary steam header for heatingandforoverspeedtriptestingbeingperformedontheUnit1 main feed pumps, and the full-flow of " cold auxiliary feedwater for about the first two minutes. All parameters recovered normally when the supply steam to Unit I was secured (the main steam isolation valves were closed) and the turbine-driven auxiliary feedwater pump was secured, both motor-driven pumps were left in service.
Steam generator levels and steam pressure behaved normally for a high-power trip, though steam flow and feed flow channels did not all " track" each other correctly on the Prodac 250 computer. Job Orders (the licensee's method for initiating maintenance) were written for correction.
Feedwater isolation valves FM0 201 (loop 1) and FMD 204 (loop 4) did not close as initially expected with reactor trip and low average primary coolant temperature. Subsequent investigation determined the " reactor trip" input to the control logic for these valves comes from auxiliary contacts (which close when the breaker opens) on the "A" reactor trip breaker. Since RTB "A" failed to open, the auxiliary 5
h contacts were never closed and the valves did not receive that portion of their required actuation logic. Thus, they did perform as designed. As noted above, all four loop feedwater regulating valves (which are not single-train oriented) did isolate.
- c. Operator Actions At the time of the reactor trip, the Unit 2 Control Room was staffed by a Unit Supervisor (SRO), a Reactor Operator No. 1 (RO) and a Reactor Operator No. 2 (under training). This staffing met facility license requirements. The operators apparently had no prior indication of any problem. They had just stabilized reactor power at about 80 percent following a several hour ramp up in power (approximately 35 per hour) from 50-percent. All major control systems were in automatic.
The first problem indications noted by the operators were multiple alarm actuations followed closely by rod bottom lights, indicating a reactor trip. The Reactor Operators No. I and No. 2 focused their attention on recovering the primary plant and its support systems.
Auxiliary feedwater automatic start was verified effective, then focus went to recovering pressurizer level, restarting pressurizer heaters and restoring normal letdown. The Unit Supervisor after verifying correct automatic actions began working to recover steam generator levels. He isolated the main steam stop valves to limit the primary system cooldown until various steam supplies could O be secured.
A few minutes after the trip, an operator noted that the "A" reactor trip breaker had not opened. By this time the Operations Superintendent (SRO) was present in the control room. Following discussion with the Unit staff, he made the decision not to trip RTB "A" using the manual
" shunt", trip from the main controT room. This decision was consistent with approved licensee procedures for post-trip recovery; i.e., there is no procedural requirement to use the manual shunt trip following a automatic reactor trip provided all rods indicate in and the reactor is subcritical.
In the opinion of the AIRT, operator actions during and following this event were prudent and correct.
- d. Source and Promulgation of Trip Signal The reactor trip initiating signal was an indicated reactor coolant loop low flow (from the reactor coolant pump No. 22 breaker "open" relay) above P8 (30 percent power). This was a consequence, as were several other false early event indications, of a momentary voltage reduction on Control Room Instrument Distribution (CRID) inverter No. 2. CRID II became an early suspect in the licensee and AIRT reviews because it is the Class IE power supply associated with the RPS relays which actuated. Protection Set II (testing activity in O- progress), and radiation monitor ERS 2300 (which was being worked on at the time of the event were also suspect). Also pointing to problems with CRID II was the observation that the Prodac 250 and OSM outputs had a similar appearance to previous reactor trip events involving loss of a CRID inverter.
6 t
Other early concerns involved the potential that the solid state O protection system (SSPS) had not correctly transmitted a protective signal to the "A" reactor trip breaker, or that there was a relationship between the failure / problem which initiated the spurious low reactor coolant flow signal and the subsequent failure of RT8 "A" to actuate. The SSPS was verified to have provided a proper actuation signal when it was established the undervoltage trip attachment on RT8 "A" had, in fact, actuated. The sequence of events record shows the de-energ8zation of the undervoltage coil, and separate independent verifications were subsequently made which established the indicated coil voltage in the control room panels and the coil voltage measured locally at the breaker panel were both essentially zero. This infomation separated the two issues of unknown source /cause of the trip and failure of the RT8 to actuate.
Prior to release of the SSPS for general troubleshooting, selected "as found" determinations of proper system functions were made by performance of the following surveillance tests:
- 2 THP 4030 STP.145 " Reactor Protection Logic Surveillance"
- 2 THP 4030 STP.137-1 " Reactor Coolant Pump No 2 Bus Under-frequency Bus 2 C Surveillance Test"
- 2 THP 4030 STP.188 " Reactor Coolant Pump Breaker Position Reactor Trip Test" Successful completion of these tests, as verified by the AIRT,
_O confirmed that the SSPS functioned correctly.
In pursuing the cause of the trip signal, the licensee developed investigative procedures involving the SSPS Protection Set II, ERS 2300, and the CRID II inverter. These procedures were discussed with, concurred in, and selectively observed by members of the AIRT.
On November 3, during continuing investigations of ERS 2300, which had been returned to service just prior to the reactor trip event, but which had failed again November 1, a licensee Control and Instrument technician identified a degraded (scorched) and intermittently failing transformer to the " photo-helic" control flow circuitry. This transformer is powered from CRID II. It is believed that the " heavily loaded" CRID II (normally operating near full-amperage capacity) suffered a momentary voltage drop during intermittent shorting of the ERS 2300 w. col circuit transformer.
This momentary voltage drop was apparently of sufficient magnitude (about 60 v.) to actuate some of the smaller, more sensitive relays powered by the CRID II inverter, including the " reactor coolant pump breaker open" relay which precipitated the low flow reactor trip.
- 3. Reactor Trip Breaker Evaluation
- a. Breaker History In review of the Donald C. Cook Unit 2 reactor trip breaker "A" O fatiure eveat of Oct her >>. 2*as the ^IRT revie -d the foiiewiao documentation:
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l lh i
- Condition Report 12-07-85-1445, dated July 23, 1985.
A crack was discovered in a DB-50 stationary contact pole base. ,
o Job Order 43332, File EE-SG-08-50, dated July 27, 1985. !
! "Perfom acceptance test on D8-50 breakers for Unit 2. Perform f l applicable portion of test procedure 12 MHP 5021.082.023."
- Receipt Inspection Report ASP 9007, dated August 20, 1985.
l D.C. Cock receipt inspection report for refurbishing Unit 1 l 08-50 breakers.
1 i i
- JobOrder14087,FileEE-SG-08-50,datedAugust 20, 1985.
" Reactor trip breaker "A" smoked trip coil.
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- Condition Report 2-08-85-1672, dated August 20, 1985. ;
" Reactor trip breaker "A" had smoke com'ng from inside." l
- Receipt Inspection Report ASP 7949, dated July 29, 1985.
D.C. Cook receipt inspection report for refurbishing Unit 2 l D8-50 breakers.
- **2 THP 4030 STP.144 Revision 1 !
" Reactor Trip Breakers Surveillance Test" ;
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l * **2 THP 4030 STP.180, Revision 1
" 5" ( 2 ) ' ""'""' " ' ' '" ' " "' " ' ' ' 5 ''"'"
'O * **12 MHP 5021.082.023 Revision 1
, " Maintenance, Inspection and Repair Procedure for Westinghouse '
Type D8-50 Air Circuit Breakers Installed as. Reactor Trip -
i Sreakers and Reactor Trip Sypass Breakers." :
i During training / dry-runs to perfo m **12 MtP 5021.082.023 in mid-July, !
j 1985 while both Units were shut down (Mode 5/6), maintenance personnel i identified and documented that a 08-50 stationary contact pole base ;
j exhibited a crack on the top of the base plate. As a result, on ;
j about July 25, the Unit 1 and Unit 2 reactor trip and trip bypass l l
breakers (8 total) were sent to the vendor (Westinghouse) for ;
l refurbishment. The refurbishment included: replacement of twenty-four ,
l (24) pole bases; replacement of eight (8) undervoltage trip attachments, i 3
installation of four (4) trip counters (Unit 1 only, Unit 2 to be !
l performed at a later date); and,~ additional parts as determined by [
inspection at the refurbishment facility. The Unit 2 breakers were ;
received back at the Donald C. Cook plant site on July 29, 1985 and ;
i the Unit 1 breakers were received back at the plant site on August 19, l 1985. The receipt inspection for the breakers (Unit 1 and Unit 2) consisted of inspection for: storage / i
' verification; surface contamination; packaging shipping compliance; quality damage; nameplate ;
verification; and review of the Westinghouse Quality Release j documentation. All of the breakers passed receipt inspection, j l
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I Q During acceptance testing on July 30, 1985 for the Unit 2 DB-50 breakers using ** 12 MHP 5021.082.023, maintenance personnel found ,
additional cracked base plates on each of the four breakers. The '
base plates were replaced at the plant by Westinghouse personnel.
Following this on-site base plate replacement the Westinghouse 4
personnel witnessed successful acceptance testing by D.C. Cook personnel. During this inspection, no Job Order, plant approved 4 procedure, or Westinghouse procedure documenting these repairs were available for review by the inspectors. On November 8, 1985, the
- Maintenance Superintendent informed the inspector that the repair
} was apparently not done by a procedure, however, it was accomplished by a qualified technician under supervision of a lead engineer and in the presence of Westinghouse quality assurance personnel. Failure ,
to document the above identified on-site repair by Job Order or -
4 approved procedure may be a violation of plant administrative requirements. This is an unresolved item pending additional review. ,
(Unresolved Item (316/85035-09)).
- the AIRT on-site investigation, the licensee was asked to During/
obtain provide detailed Westinghouse documentation of the July 1985 i refurbishment at the Westinghouse facility. This information was provided to the resident inspector on November 6,1985. Inspector i review of the licensee's procedure used during the on-site acceptance testing determined that steps in **12 MHP 5021.082.023 pertaining to .
lubrication of the UVTA were marked "not applicable" because "the i
n V
UVTA was lubed at the factory, therefore steps pertaining to before Iube do not apply". The Westinghouse refurbishment document reviewed l
- by the inspector stated that lubrication may be necessary if UVTA test i 1 results are unsatisfactory, however, the refurbishment document did not require lubrication and did not require verification that the UVTA was lubricated. The inspector questioned if the "not applicable" notation in Procedure ** 12 MHP 5021.082.023 was appropriate, since the licensee did not have documentation that the UVTA's were lubricated at the factory. This is an open item pending further l review by the resident inspectors (0 pen Item 315/85035-10). Other than the cracked base plates (identified by the licensee), the lack of documentation for onsite repair (identified by the inspector) and questions pertaining to lubrication of the UVTA (identified by the inspector) no additional problems were identified during acceptance
- testing.
! A review of equipment history for the reactor trip breakers since refurbishmentdeterminedthatduringcontrolroddroptimingtesting on August 20, 1985, the Unit 2 reactor trip breaker 'A" was found to have had smoke coming frem inside the breaker cubicle. Condition Report 2-08-85-1672 and Job Order 14087 were written to investigate and effnct repairs. The condition report documented that the closing coil was producing the smoke. The reason for the smoking coil could not be definitely determined, but overheating due to a 1 misaligned or hung-up shutoff contact (which kept the coil continuously energized) was suspected; these parts were adjusted.
- A functional test (**12 MHP 5021.082.023) of the reactor trip breaker was satisfactorily performed and the trip breaker declared ;
)
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_ - . . _ . - - - - - - - - - - - _ _ - - . . - - , ~ _ _ .
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}
4 h The inspector also reviewed the Unit 2 bi-monthly breaker surveillance test (**2 THP 4030 STP.144) performed during the period of January 1985 through October 1985 and the Unit 2 startup breaker surveillance ;
i test (**2 THP 4030 STP.180) performed on October 22, 1985. These surveillances were performed on the required frequency. The inspector 1 noted that Steps 7.11 and 8.11 of STP.144 require verification that the UVTA voltage meter indicates approximately 0 volts. It is unclear why the procedure does not specify an acceptance value or range. For ,
example, the range of values recorded for Step 7.11 was 0 to 12.8 volts. The equivalent steps in STP.180 specify an acceptance value of less than 15 volts. This was discussed with licensee management.
! b. Breaker Failure Investiestion i At 1:58 p.m. EDT on October 29, 1985, the Unit 2 "A" reactor trip breaker failed to operate on receipt of a valid trip signal from the reactor protection system. The in-series "8" reactor trip
, breaker functioned correctly and the reactor was shut down.
Immediately following the trip, personnel from the site resident i inspector office and the Palisades resident inspector office !
verified the licensee's initial actions and assessed the status of the plant. In addition, agreements were reached, via telephone,
- between Mr. C. W. Hehl (NPC Section Chief - Region III) and Mr. W. G. Smith, Jr. (Plant Manager, Donald C. Cook) pertaining to quarantining the Unit 2 "A" reactor trip breaker and other suspect components pending further evaluation and restrictions on startup of 4
Unit 2 and Unit 1 (in Mode 3, completing post refueling testing). A l Confirmatory Action Letter ( See Paragraph 5 below) was subsequently i issued on October 30, 1985 documenting these and other licensee /NRC
- agreements. . I j Region III dispatched a Augmented Incident Response Team (AIRT) team consisting of a team leader (W. L. Forney, Region III Section Chief) 4 and a region based specialist. The team arrived on site at approximately 8
- 00 p.m. on October 29, 1985. An additional region based specialist arrived on site at approximately 8:00 a.m. on i October 30, 1985. Team members from NRC Headquarters and Franklin '
- Research Center arrived on site at approximately 8
- 00 p.m. on October 30, 1985.
I The licensee's site team consisted of a team leader (M. P. Alexich,
! Executive Vice President, AEPSC) team members from the site and ;
corporate office, and representatives from the breaker vendor. The licensee site team was onsite the afternoon of October 30, 1985.
- Late on October 29, 1985 the Region III AIRT Team members met with ,
l licensee onsite management and agreed on the approach for .
- determining why the breaker did not function. The " quarantined" condition of the breaker and other suspect parts was reverified at this time.
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y i
h On October 30, 1985 the licensee developed a procedure (un-numbered) for in situ inspection of the failed breaker. The procedure stressed the preservation of evidence of the cause of the breaker failure. Therefore the inspection was visual only, and the breaker 4
components were not touched during the inspection. An NRC inspector 4
witnessed the inspection and the " dry-run" on a " spare" breaker that preceded the inspection. The " dry-run" contra-indicated certain
, proposed uses of a borescope for performing the visual inspection, i and the " live-run" was performed without these potentially
, problematical steps. No indication of the cause for the breaker
< failure was identified during the visual inspection. It appeared j the undervoltage trip attachment (UVTA) which should have tripped the breaker via actuation of the trip bar, had moved from its normal i position and appeared to be touching the trip bar.
! After the breaker was inspected, the licensee developed a procedure
(**2 MHP-SP-105 "Special Procedure for Inspection of Unit 2 Reactor Trip Breaker A, Serial No. 324Y7277B") on November 1, 1985 for the removal of the undervoltage trip assembly (UVTA), removal of the circuit breaker, and the electrical and maintenance analysis of '
why the breaker failed to trip.
The procedure was developed, reviewed and approved in accordance with the licensee's administrative Procedures. Procedure development was followed by a " dry-run" of the functional portions of the procedure, i
, O U
performed in the presence of the AIRT Team. After the dry runs were satisfactorily completed, the licensee documented the as found condition of the Reactor Trip Breaker A. This document included )
- verification by voltage measurements that the "A" breaker UVTA coil l
had deenergized in response to the trip signal, and measuring and i recording the location of various breaker components. Documentary photographs were taken throughout the performance of the procedure.
! The circuit breaker trip function was disabled by tying the UVTA reset lever and the trip bar of the circuit breaker in place, such
, that an accidental trip would not occur to upset the "as found" condition of the breaker or endanger personnel engaged in the investigation. The UVTA was removed from the circuit breaker, t
bolted to a specially prepared board and moved to a secure location -
in the electrical machine shop.
- The ties placed to prevent the circuit breaker from tripping were removed and the breaker tripped using a calibrated spring scale.
The scale was initially pulled horizontally, being attached to the trip bar by a string run over a clamp above the breaker. An administrative upper pulling force limit of 70 ounces was used.
- The force necessary to trip the breaker was 36 ounces, as measured horizontally. The circuit breaker was removed from its cubicle and ten (10) repetitions of the force measurements performed. The forced measured by five tests pulling vertically on the trip bar l A ranged from 18 to 22 ounces and averaged 20 ounces; the normal j U upper acceptance limit in this, test is 31 ounces.
11
h The UVTA and RTB were removed to the electrical shop for further testing. The UVTA was inspected in the electrical shop. No indications of the failure were identified during this inspection.
The UVTA was replaced on the circuit breaker and the coil wires
, connected to a test source. The coil was energized, the breaker -
reset and the coil de energized. Upon coil de-energization, the breaker tripped normally. This test was repeated four times on slowly decreasing voltage with satisfactory results. The trip margin measurements were then performed using the applicable portions of **12 MHP 5021.082.023. The trip bar was loaded with twenty ounces of excess weight and the UVTA cycled (energized /
de-energized) five times. The breaker failed to trip each time.
The weight on the trip bar was reduced to sixteen ounces and the UVTA cycled three times. The breaker failed to trip each time.
The weight on the trip bar was reduced to ten ounces and the UVTA i cycled three times'. The breaker failed to trip each time. Five tests with five ounces attached resulted in one failure, one clear
- success, and three successes characterized by breaker actuation on a second UVTA lever strike on the trip bar after initially rebounding.
All weights were removed from the trip bar and the UVTA cycled three times. The breaker tripped each time. This testing established inadequate lifting force output from the UVTA as the root cause of the "A" trip breaker failure of October 29, 1985.
^
On November 2, 1985 the UVTA from the "A" trip breaker was placed in (U) a double locked box (Plant Manager and Westinghouse each had a key to one lock). The box and the "A" trip breaker were placed in a locked cage located in the electrical machine shop, and remained there at the completion of the inspection, pending shipment to the
- vendor for further investigation.
After the "A" trip breaker and associated UVTA were isolated, a course of action leading to startup of Units 1 and 2 was discussed.
The licensee committed to perform the 18 month surveillance /
maintenance procedure (**12 MHP 5021.082.023; which includes the 20 ounce trip margin verification) on the remaining breakers (four installed in Unit 1, three installed in Unit 2 and the replacement breaker for the "A" reactor trip breaker). The four Unit 1 reactor trip breakers and the replacement breaker for Unit 2 successfully completed the surveillance / maintenance procedure. On each of these breakers the UVTA was lubricated as required by the Surveillance procedure. When the surveillance / maintenance procedure was commenced on the Unit 2 "B" reactor trip breaker, the licenae decided to conduct the " trip force margin test" without prior lubrication of the UVTA. The change in sequence was decided on because the lubrication /
lack of lubrication was the only obvious difference between the Unit 2 "A" breaker which failed to trip and the five breekers which had just successfully completed the surveillance / maintenance procedure. During the performance of the trip force margin test with 20 ounces on the trip bar, the "B" breaker failed to trip when the UVTA was de-energized. The test was repeated with no weight on the trip bar; the breaker tripped. The test was repeated with ten ounces 12
k j
I h on the trip bar; the breaker tripped. The test was repeated with twenty ounces on the trip bar, the breaker did not trip. The test i' procedure was modified to trip the breaker using a spring scale and measure the tripping force. The test was performed four times. The breaker, still with twenty ounces on the trip bar, then tripped satisfactorily using the UVTA. This testing was performed for the "A" bypass breaker, and "B" bypass breaker and two spare UVTA; all passed. The " degraded" UVTA for the "B" breaker was removed from the breaker and isolated in the same manner as the UVTA for the "A" breaker.
The cause of the failure of Unit 2 reactor trip breaker "A" to function correctly on receipt of a valid trip signal on October 29, 1985 (and several additional times during subsequent testing) was concluded to be inadequate force on the breaker trip bar on de-energization of the undervoltage trip attachment. The UVTA root-cause failure mechanism remained unknown at the conclusion of this inspection. Investigation into the UVTA failure mechanism will be conducted by Westinghouse with oversight by the licensee and the NRC. :
- 4. Confirmatory Action Letter i A Confirmatory Action Letter from James G. Keppler (NRC-RIII) to John E. Dolan (AEPSC) was issued on October 30, 1985 as noted in Paragraph 1 above. The line items of the Confirmatory Action Letter 1
_O and status of licensee implementation are as follows:
- a. Conduct a thorough review to determine if a trip signal actually was received by the Reactor Protection System (RPS). (Confirmatory Action Letter 316/85035-01).
(Closed): A trip signal (RCS low flow above P-8) was received
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and correctly processed and output by the RPS. See Paragraph 2.d above. ;
l b. Determine why the reactor trip breaker failed to trip.
(Confirmatory Action Letter 316/85035-02).
(0 pen): The reactor trip breaker failed to trip due to
! inadequate tripping force from the undervoltage trip attachment. This was a new device installed in July 1985 .
by the vendor at his facilities. The root cause of the undervoltage trip attachment inadequacy remains under investigation by the vendor with licensee and NRC oversight.
l See Paragraph 3.b above.
1
- c. Determine why two of the four steam generator feedwater isolation valves failed to close.as anticipated following the trip.
(Confirmatory Action Letter 316/85035-03).
(Closed): Feedwater isolation valves FM0-201 and 204 failed to close due to incomplete actuation logic directly related to the 13 i
m, - - +
h failure of reactor trip breaker "A" to open. They performed as designed. See Paragraph 2.b above.
- d. Maintain all affected equipment related to the affected Reactor Protection System train, to include inverter power sources, in the "as found" condition. Therefore, take no action such as removing or tripping the reactor trip breaker which would destroy or cause to be
. lost, (other than necessary to protect the health and safety of the public) any evidence which would be needed to investigate or reconstruct this event. (Confirmatory Action Letter 316/85035-04).
(Closed): The specified equipment was protected and controlled as required, and was released for incident investigatien and reconstruction only as specifically approved by the NRC AIRT Team based on the Team's review of and concurrence with procedures developed specifically to maximize collection of
- valid information. See Paragraphs 2 and 3 above.
- e. Review operator actions taken immediately following recognition of the failure to trip and determine if these actions were in i accordance with your procedures and policies. (Confirmatory Action Letter 316/85035-05).
(Closed): Neither licensee nor NRC reviews of operator actions identified any violation of licensee procedures and policies or other requirements. See Paragraph 2.c above.
- f. Develop troubleshooting plans and procedures, and provide these to the NRC site team for their review and concurrence prior to initiating any trouble shooting of the affected' equipment.
(Confirmatory Action Letter 316/85035-06).
(Closed): The licensee implemented this item as specified, which served as the basis for release of the equipment for event investigation / reconstruction as noted for item 316/85035-04 above. See also Paragraph 2 and 3 above.
- g. Submit a formal report of your findings and conclusions to the NRC Region III Office within 30 days. (Confirmatory Action Letter 316/85035-07).
(0 pen): At the conclusion of the inspection, the report date had not yet arrived.
- h. We further understand that startup of both Units 1 and 2 will not occur until authorization to restart is obtained from the Regional Administrator of his designee. (Confirmatory Action Letter 316/85035-08).
(0 pen): At the conclusion of the inspection, the licensee had neither requested nor received authorization to restart either Unit 1 or O Unit 2, but the expectations of NRC concerning information 0
1 14
h requirements in support of the anticipated request, and the mechanisms for submittal and processing of the request had been fully discussed with licensee representatives.
- 5. Persons Contacted M. P. Alexich, Executive Vice President, AEPSC W. G. Smith, Jr. , Plant Manager B. Svensson, Assistant Plant Manager A. Blind, Assistant Plant Manager K. Baker, Operations Superintendent J. Stietzel, Quality Control Superintendent J. Allard, Maintenance Superintendent L. Gibson, Technical Superintendent-Performance A. McCabe, Major Transmission Equipment Engineer, AEPSC B. Auvil, Nuclear Safety and Licensing Engineer, AEPSC J. Anderson, Electrical Generation Engineer, AEPSC C. Miles, Control and Instrument Supervisor P. Helms, Control and Instrument Assistant Supervisor S. White, Maintenance Foreman R. Sims, Shift Technical Advisor R. Ptacek, Shift Technical Advisor C. Springman, Shift Technical Advisor R. Blythe, Shift Supervisor -
J. Hylok, Control and Instrument Foreman M. Parvin, Site Service Manager - Westinghouse O C. Geiss, Technical Service Representative - Westinghouse A. Deb, Technical Service Representative - Westinghouse R. Schreiner, Field Service Engineer - Westinghouse
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The inspectors also contacted a number of licensee and contract employees and informally interviewed operation, technical and maintenance personnel during this period.
. 6. Open Items I
Open Items are matters which have been discussed with the licensee, which will be reviewed further by the inspector, and which involve some action on the part of the NRC or licensee or both. An open item disclosed during the inspection is discussed in Paragraph 3.a.
- 7. Unresolved Item Unresolved items are matters about whlch more information is required in order to ascertain whether they are acceptable, violations, or deviations. An unresolved item is discussed in Paragraph 3.a.
l
- 8. Additional NRC Actions
- a. As a result of this event, on November 5, 1985 the NRC issued IE Bulletin 85-02 requiring licensees who did not have automatic l (A shunt trips installed as part of their reactor trip breakers to perform testing on the undervoltage trip assembly (UVTA).
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- c. On November 6, 1985, NRC Region III granted concurrence on the licensee's request for restart of both Units 1 and 2. This concurrence was granted based on the licensee having satisfactorily met the requirements of the October 30, 1985 CAL: with exception of submittal of a formal report of the findings and conclusions regarding this event, and the licensee having installed the automatic shunt trip feature on Unit 2.
- 9. Conclusion The actions of the NRC Augmented Incident Response Team and of the licensee were directed toward conduct of a thorough and disciplined investigation of a failure of a reactor trip breaker to actuate in response to a valid reactor trip signal of October 29, 1985. The investigation proceeded in a manner which was designed to assure preservation of evidence.
The fallowing significant facts were ascertained: ,
- a. The reactor protection system functioned correctly in processing the trip signal, and the undervoltage trip attachments on both breakers
"^" "a "a" r d - a raiz d-O
- b. The undervoltage trip attachments (UVTA) on both trip breakers were degraded, with the lift force output on the "A" trip breaker attachment at such a low level as to be unreliable in tripping the breaker. This was the root cause of the breaker failure.
- c. The performance of plant operators, and the operation of other major or safety-related plant systems, were as expected and designed.
t Though the reason for the degraded UVTA performance was not conclusively determined by this inspection, arrangements were made to make that determination. Meanwhile, all plants without diverse automatic trip l
breaker actuation (via tt.e automatit-shunt trip) were instructed by IE
' Bulletin 85-02 to perform such testing as necessary to demonstrate acceptable UVTA performance.
e O
16
- - - _.. - - _ _ _ - _ _ _ _ _ __