ML19242D903
| ML19242D903 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 05/17/1979 |
| From: | Mehler B METROPOLITAN EDISON CO. |
| To: | |
| References | |
| NUDOCS 7908280802 | |
| Download: ML19242D903 (45) | |
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UNITED STATES OF AMERICA
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L,1 NUCLEAR REGULATORY COMMISSION I
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1 In the Matter of:
2l IE TMI INVESTIGATION INTERVIEW i
3) of Mr. Brian A. Mehler j
Shift Supervisor M
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Trailer #203 9
NRC Investigation Site TMI Nuclear Power Plant 1 01 Middletown, Pennsylvania 11l May 17,1979 12!
(Date of Interview) 1$
July 2, 1979 (Date Transcript Typea) i 213 15l
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(Tape Numcer(s))
16; 17; i
18:
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20l 21; NRC PERSONNEL:
'22' Mr. Donvin Hunter 23!
Mr. Owen C. Shackleton 24 25l f D ? Y b ? 0 S.-
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lf SINCLLIR:
The following interview is being conducted of Mr. Brian A.
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Mehler.
Mr. Mehler is a shift supervisor at the Three Mile Island i
3f nuclear power facility.
The present time is 11:43 p.m. eastern daylight time.
Today's date is May 17, 1979.
The place of tha interview is 4
5 trailer 203 which is located immediately outside the south gate to the Three Mile Island site.
The individuals present for the interview 6
7l will be Mr. Dorwin Hunter.
Mr. Hunter is an Inspection Specialist, Performance Appraisal Branch, I&E Reactor Construction Inspection, g
U.:. Nuclear Regulatory Commission.
Also present is Mr. Owen C.
g Shackleten.
Mr. Shackletor, is an investigator, Region V, U.S. Nuclear O
Regulatory Commission.
My name is John R. Sinclair.
I am an investi-gator, Office of Inspector and Auditor, U. S. Nuclear Regulatory i
Commission.
Prior to the interview being recorded, Mr. Mehler was 13i provided a copy of a document explaining his rights concerning informa-l Lion to be obtained regarding the incident at Three Mile Islanc.
In 15; addition, Mr. Mehler was apprised of the purpose -
he investigation, its scope and the authority by which Congress autho. I le Nuclear Regulatory Commission to conduct the investigation.
On the second 18!
page of the advisement document, Mr. Mehler has answered three cuestions.
19i The questions and Mr. Mehler's replies will now be recorded as part of 20' the interview.
21!
22!
SINCLAIR:
Mr. Mehler, c understand the document?
23l l
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MEHLER:
Yes.
25l qq i
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SINCLAIR:
Okay, thank you.
Second question. Do we have your permission l
f 2l to tape the interview?
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i MEHLER:
Yes.
4 5
SINCLAIR:
Thank you.
Third question. Do you want a copy of the 6
7 tape or transcript?
I 8j MEHLER:
Yes.
g 10f SINCLAIR:
Thank you At this time Mr. Mehler, I will ask you to please provide us a brief summary or synopsis of your work experience j
and training as it's related to the nuclear industry.
13; i
14' MEHLER:
I started in the nuclear industry in the training program conducted down at Three Mile Island, I believe it was the year of 1968 17)l or '69.
That consisted of a 42-week training program conducted by Met c.d, by Richard Zechman at the Island.
It also consisted of two weeks at Penn State at their reactor.
Also in that training program there lot l
was a two-week course given down at E&W After that period of time 20j and up until the licensing, I licensed on Unit I as a CRO.
Then later 21l on, I was a CR0 at Unit 1, I'd say approximately five years.
I don't 22 know.
Then I went to Unit 2 as a shift foreman, and then I licensed 23 on Unit 2 as an SRO.
And from then I licensed on Unit 1 as an SRO, 24l and right now I currently carry an SRO license on both Unit 1 and Unit 25j 2.
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SINCLAIR:
Okay, thank you very much.
Mr. Hunter?
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i 3l HUNTER:
Thank you Brian.
I have reviewed some other interviews that 4f have been done and also have picked out some questions from other 5
interviews that have been done with other people and I hope to discover 6
s me speci fic ai eas and maybe we can move right along.
It's is my 7
understanding that you arrived on site on 3/28 approximately 5:45 in the morning.
Were you called in?
8 9!
MEHLER:
Yes, I was called at home, I'd say roughly at 5:00 in the 10 morning.
12!
HUNTER:
Who called you in, Brian?
la, 14i 15:l MEHLER:
I don't remember the gentleman's name.
It was some engineer.
16:
HUNTER:
Any particular reason they called you in?
17;;
i 18!
MEHLER:
Normal procedure is to get the second shift supervisor in case of any trip for recovery.
20t 21 HUNTER:
So you were the day shift supervisor who was coming in?
22 23; j
MEHLER:
I would have been the day shift supervisor on Unit 1 that 24!
particular day but the previous day I was on Unit 2 so he called me.
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4 lt HUNTER:
Okay, thank you Brian.
When you arrived at the plant you i
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pointed out, again, I am going to try to go along and key on some of 3
y ur comments previously, that you reviewed the control board and the 4
status of Unit 2.
Craig Faust, Frederick Scheimann, Zewe, I believe 5
you said Mike Ross and...
61 MEHLER:
Ken Bryan 7
8 HUNTER:
....and George...
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10' MEHLER:
I don't remember seeing George.
Ken Bryan was there I know.
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HUNTER:
All right, and then Mr. Zewe, Scheimann, and Faust were at the pressurizer area.
14!
15; MEHLER:
At the area, it was Scheimann, Fredericks and Mike Ross.
I j
think Bill and Faust were over basically in front of the feedwater 17; area.
1Bt 191 HUNTER:
Fine, okay.
Let's see.
You indicated by looking at the 20t l
pressure chart that the pressure was approximately 900 pounds.
21l 22)
MEHLER:
Roughly 900 pounds.
I just glanced at it and it looked in 23 the area of 900 pounds and it was more or less stable.
24 25i 1
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r lf HUNTER:
The status of the reactor coolant pumps at the time....
I 2;
i 31 MEHLER:
Were secured.
i 4l S'
HUNTER:
Were off... okay.
And you noted that the B steam generator 6;
was isolated?
i 7
g MEHLER:
Uh, Bill just told me that he just finished isolating B gl steam generator.
10 HUNTER:
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Okay, and that left the AC generator then available for i
removing decay heat?
13 MEHLER:
Yes.
15i 16; 9
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But one pump was running, letdown was on and 16 valve was.
I 18j MEHLER:
I don't, know the exact position of 16 at that time.
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21;l HUNTER:
..being used or available.
Did you look at the makeup flow or at the high pressure injection flow?
23 MEHLER:
No, I didn't.
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1 HUNTER:
Did you look at the letdown flow?
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3 MEHLER:
No, I didn't.
4!
5l HUNTER:
Okay, I just want to make sure I get all the information I l
6; can get.
All right.
Carl Guthrie, you-indicated arrived somewhere 7
right at that time?
8 MMLER:
It was a couple of minutes after I did.
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10 HUNTER:
All right.
He went down and checked the pressurizer heater breakers.
13 i
MEHLER:
Yes, he did.
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HUNTER:
You fellows have had trouble with those breakers before?
i 171 l
MEHLER:
Yes, we've been having problems with the pressurizer heater 18l breakers tripping.
19i 20!
l HUNTER:
Okay, that's an environmental heating arer. involved?
21!
i 22' MEHLER:
Due to the environment they're in, the thermals seem to tend 23 to heat up and trip.
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7 11 HUNTER:
Did Mr. Guthrie get back to you and tell you what the status t
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of the heater breakers were?
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MEHLER:
Yes, he did get back to me and he said the status of them, L
5 that all the breakers were closed.
6 7
HUNTER:
Okay, so that meant that you had all the pressurizer heaters 8
available to you at that time.
Okay.
Were there any other significant gj items that you looked at primary parameters or determined the status 10 f the plant that you recall?
11!
MEHLER:
12 Well, the main things I looked at there is most of the 13 pe Pie were directly in front or the pressurizer pressure and level.
y And I noticed the pressure was low and I noticed the pressurizer level w s full.
- 15i, It was pegged high, you know.
You know. at that pressure y u pop the bubbles in the hot legs, 6
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HUNTER:
You over again, that it indicated to you that.. the pressuri 'r 18l I
being solid indicated to you that they had bubbles in the hot legs.
191 20!
I MEHLER:
Yes.
21; i
22l HUNTER:
of the plant.
Had you seen this before?
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MEHLER:
No, not personally, I haven't.
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31 HUNTER:
Had you read any plant transients or had any training associated i
4f with that type of a pr.oblem?
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6j MEHLER:
No, I haven't but I do know it happened previously on another 7
shift.
That they did pop the bubbles in the hot-legs.
8 gj HUNTER:
Can you recall what the conditions were when that happened?
i 10 Was it during a plant trip?
11 MEHLER:
No, it wasn't.
I believe it was during a start up.
Not a 12 start ap, a heatup.
13 14!
((UN TER:
A heatup?
15 16!
MEHLER:
I believe.
I never got the specifics on it.
18[
HUNTER:
Okay.
You say, you indicated that the B steam generator may i
19!
have been dry.
Was it dry or had they just bottled it up?
21!
MEHLER:
They told me they just bottled it up at the time.
42 23l HUNTER:
Okay.
24:
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9 li MEHLER:
In fact, Bill looked at me and said "We just finished bottling 2
up B steam generator because we had a tube rupture in it."
3 HUNTER:
Did he indicate to you the reason he felt like he had a tube 4l 5
rupture?
6 MEHLER:
Because of 748 in alarm.
7 8
gj HUNTER:
A radiation monitor 748, is that the air ejector vent monitor?
I 10 MEHLER:
Yes, that's the offgas.
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HUNTER:
He indicated that he had a...
13) l 14!
MEHLER:
Indication of a number tube leak.
15 16 HUNTER: Okay.
You indicated then that you went to the computer and called out some values, temrseratures or pressures on the meter?
18!
19!
MEHLER:
I punched out the thermocouple values for the code relief 20l l
valves and the electromatic.
Looking at the values I roughly see the two codes were identical - well not identical, they were within a 22 couple degrees of each other and I believe the electromatic was roughly 23 26 degrees higher.
In the neighborhood of that.
It was higher and 24 I
this indicated to me that it was weeping.
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10 1.
HUNTER:
Had you noticed then in your review at the control board that 2
the power operated relief valve indicated closed?
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4 MEHLER:
It indicated closed, yes.
I SI 6
HUNTER:
Okay, and then you apparently indicated to Fre'd Scheimann 7
that he should close the..
I al 4
MEHLER:
Block valve...
g 10l HUNTER:
The block valve.
And Fred in fact closed the block valve and the.
13l MEHLER:
At that point pressure started to recover.
15!
HUNTER:
Did you notice reactor building pressure at that time?
17' MEHLER:
No, I didn't.
I did notice, though, that they already had the emergency river pumps running.
19!
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HUNTER:
And they would have those on for what reason?
j 21 t 22l MEHLER:
Trying to reduce the pressure in the building.
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HUNTER:
Extra cooling to the fan coolant...
2!
l 3l MEHLER:
Yes, a larger system.
4i 5{
HUNTER:
Okay.
Can you clarify for me in your own words how you feel 6
about the block valve on the power operated relief valve? And have 7
y u experienced trouble with the block valve in your job on Unit 1 --
g you've been on Unit 1 and Unit 2 -- and give us your feeling about the block valve.
And I guess I am a littic surprised that the guys didn't g
close it before then.
10 lli MEHLER:
12 I can't be specific on the block valves saying that we actually had problems with the block valves.
I do know of problems 13 with the spray valves on either sticking open or not opening and I n n e n n n e spay va he has been less Oan 15 desirable, sometimes the limit switchet break.
I'm trying to figure
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out if we ever had any problems with the block valves sticking shut.
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18l HUNTER:
Did it ever stick open or close on you?
20 MEHLER:
What, the spray?
22;i HUNTER:
The block valve on the power operated leak valve?
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1 MEHLER:
Not on me specifically and I can't think of any incident.
I 2:
I'm trying to, and I can't remember any specific incident where it i
3 has, but that's not saying it hasn't.
4!
5-HUNTER:
Right, okay.
In your review of the computer data, when l
Gl you're punching out the computer data for the thermocouples on the 7
discharge pipes, did you go back and look at any previous data, which 3
- had been pumped out, punched out or any previe:s temperatures?
9 MEHLER:
No, but....
10 11' HUNTER:
y Did you discuss them with Ken Bryan or Mike Rass, or Bill ewe r...
13 i
14!
MEHLER:
15 No, after I told them to close the block valve, they informed
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me that they already punched them up previously and didn't see no difference.
17l 18j HUNTER:
Okay.
Would you fira that unusual, that there wouldn't be any difference?
21)
MEHLER:
After thinking about it, what happened, I can understand way 22!
there wouldn't have been a difference.
But I would have found it 23 unusual in the beginning when it was first presented to me.
But 24l postulating that they all dump in a common line later on, it could 25!
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have fed back to all the thermecouples.
And it would have indicated a 1
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I 3
4 HUNTER:
Okay.
The time that you called out the readings was probably..
5 6
MEHLER:
2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> into it.
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HUNTER:
I'm trying to remember the number, like 6:18 or something on 8
g the computer printout.
10f i
11l MEHLER:
I think it was before that, I think it was roughly around 5 f 6.
12 13!
HUNTER:
Okay 5:50.
The power operated relief valve had opened on 14 15l the trip.
16!
i MEHLER:
Oh yes.
17!
i 18!
HUNTER:
Okay.
Would it be normal that that temperature would remain 19j relativt ly the same for a period of time? After the trip?
Had you 20!
encountered that particular problem?
21; 22l MEHLER:
I'm trying to figure out what you're saying.
That the tem-perature would hold up for a long period of time?
24 25i m'
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11 HUNTER:
Right.
2!
l 31 MEHLER:
It will hang up for awhile but, you know, it will cool down.
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41 But I think they compared the codes compared to the electromatic and I 5
think their codes thermocouples received the feedback off the electro-6 matic and that's why there was no difference.
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7 HUNTER:
Okay.
Were you aware that...
g 9
MEHLER:
10 I only postulate that, I really don't know that as a fact.
11!
HUNTER:
2 You were aware that the codes and the power operated leak valves were weeping previous to the trip?
3 i
14!
15};
MEHLER:
Previous to the trip we've had the codes indicating two up to five degrees hot temperature on the thermocouples, higher than the j
other ones.
And it wasn't just B always.
Sometimes it would be A and B.
So we didr't know which one was weeping by.
18l.
19!
HUNTER:
All right.
In your review of piant conditions, did you look at or discuss the reactor coolant drain tank.
21!
22 MEHLER:
No, I didn't.
I did not know the rupture disc was blown until later in the day.
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l 1:
HUNTER:
Okay, ar.d as far as the reactor building sumps, you didn't....
I 2'
f;j MEHLER:
No, that panel is located back around behind the console.
I 4l Even behind the concole panels.
5 6i HUNTER:
Okay.
All right, and then approximately two hours into the i
7' event the reactor coolant pumps are off.
We are on a, let me refresh 8
your memory a little bit.
You are in fact at six right in here.
The g{
pumps were and I've got the B and the A's off, okay and the pressure 10 was decreasing, the power operated relief valve is still open and 1 11 ppr ximately 2.23 hours2.662037e-4 days <br />0.00639 hours <br />3.80291e-5 weeks <br />8.7515e-6 months <br /> or two hours and twenty something minutes, t
12l the power operated relief valve was closed and then the pressure started to rise.
Did you observe the pressure increase at this time?
13 l
141 es.
15 16 17ll HUNTER:
Was the pressure increase due to anything other than the 8
w r operated relief valve being closed and the normal makeup being fed into the system?
20l MEHLER:
21;!
The heaters were already on, and the only thing that helped at that time to my knowledge that happened, is we closed the block valve to the power operated relief.
24!
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1 1!
HUNTER:
Okay, and then the pressure started the next hour.
2!
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MEHLER:
Right, started to recover.
4!
5 HUNTER:
Okay. At this point the 2 V pump was bumped.
And this was 6j where all the radiation alarm started coming in and tilen the 2 V pump 7
was bumped.
This was when the site emergency and all occurred right in here.
8 t
9 MEHLER:
Okay, that started it.
A site emergency was declared about 10ly quarter of, or ten of seven.
i 12j HUNTER:
Okay, and this is seven right here?
13 14!
MEHLER:
Okay.
16:
HUNTER:
So right in this frame is when the radiation alarm started 17!
caming in? Okay, was there any talk in this time frame, do you recall 18!
the core flood tank valves being closed?
19!
20l i
MEHLER:
No, they were open.
21l 22l HUNTER:
Okay.
Was there any talk about putting core flood tanks on 23l at this time or depressurizing and putting the core flood tanks on or 24i going down to decay heat?
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MEHLER:
Not at this particular moment.
That happened later in the l
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day.
3 i
4j HUNTER:
Okay, al' right.
I wanted to make sure.
5' 6j SHACKLETON:
Dorwin, could you identify the time you just related to?
7 HUNTER:
Okay.
We are looking at the wide range pressure curve on 8
gj the plant from the morning of the 28th from the trip through the i
10f pressure decrease and securing of the reactor coolant pumps out, and 11l we were discussing the pressure transient around 7:00 in the morning.
I 12l SHACKLETON:
Thank you.
And the name of the document you are usinc?
13 14!
HUNTER:
That's the plant wide range, reactor coolant wide range 15 pressure.
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17!
18(!
SHACKLETON:
Okay.
Thank you.
19I HUNTER:
All right.
Uh..
21i MEHLER:
Can I say something?
22l 1
23!
HUNTER:
Yes.
Go right ahead.
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i lj MEHLER:
You've got, to realize that I only arrived on site approxi-2f mately fifteen minutes before that pressure started to increase.
Now l
3l if there was talk with the other people previous to that, I wouldn't I
4i be knowledgeable....
5 l
6 HUNTER:
Yes, I understand that.
There was some discussion about 7
venting the hot legs.
8 gj MEHLER:
Yes.
I 10l HUNTER:
And could you elaborate on that and explain to me what the discussion entailed and what your intention was? What was being discussed.
13 I
14!
MEHLER:
What happr.ned is, when I arrived you could see that the bubbles were in hot legs, the pressurizer was filled and that for some means we could not recover pressure, it was basically holding.
There 17!
was two reasons:
either you had a valve open or the pressurizer 18l l
heaters weren't working.
So after we started to recover pressure by 19!
closing the block valve on electromatic, the next thing and since at j
this particular time there was no radiation alarms in, we were going 21; to go in and possibly vent the hot legs to get the steam bubble back 22!
in the pressurizer.
And we weren't going to make preparations to go in and, well, about quarter of seven all the alarms came in so it was 241 25l impossible to enter the reactor building.
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19 1,
HUNTER:
Venting the hot legs at the top of the J legs?
2:
31 MEHLER:
Uh-huh.
i 4f 5
HUNTER:
How do you
.. do you have vent valves installed there to vent?
Right at the top of the vent legs, manual valves?
61 7
MEHLER:
Yeah, manual valves.
That would have required a reactor 8
gj building entry.
l 10 g
HUNTER:
All right.
Do you know -- was this discussed between yourself?
Who all was in that discussion?
13 j
MEHLER:
I think it was.
basically it was Mike, myself and Bill
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and Gubba Marsnal1.
Cause I believe I asked Bubba to go make out an RWP so him and I could go in and do it.
17!'
HUNTER:
Okay.
So the intent was that if everything went all right 18!
you and Marshall would go in?
20l 21:l MEHLER:
Well someone had to.
22i HUNTER:
Right, no, I just said that it would have been you two to go 23 in.
Okay.
Okay, then you got into the site emergency at seven and 24 the number of people increased in the control drastically at that 25!
s a
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1l time.
Would you give us a feel for the number of people and the noise 2
level?
3 MEHLER:
The number of people -- I would say roughly the control room 4
5 had initially, probably when we declared the site emergency, we must 6i have had in neighborhood of 30 to 40 people and it progressively in-7l creased during the day.
At some point, I believe, there was as high as 70 people in the control room.
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I HUNTER:
Did that give the fellows problems at the control panel?
10 11f 12l MEHLER:
The noise level was high and it would have gave the people problems at the control panel.
Once we went into the site emergency, I more or less got away from the control panel.
14 15:
HUNTER:
Okay.
Do you know who declared the site emergency?
16, I
17 MEHLER:
Either it was Bill Zewe or Jim Seelinger.
19j HUNTER:
Okay, and do you know what they based that on?
l 21l l
MEHLER:
I believe it was based, and it's only an assumpi. ion, I think 22l l
they based it on the radiation alarms in two separate buildings from 2 31 l
the same event.
And also I believe at the same time we had the high 24l alarm on the stack vent, which would have been another indication that 25i we were into the site emergency.
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HUNTER:
All right.
During your stay on the control panel in that 2f area, did you review the source or intermediate range channels and the 3
change in the flux levels?
4!
5 MEHLER:
No, I didn't 6l HUNTER:
Okay.
Did you discuss or get involved in discussion with 7
8 the other fellows concerning emergency borate, change of baron concentra-t tion in the primary system?
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10 MEHLER:
77 No, at that particular time all the makeup -- we already had ES's.
12j A couple of them, I believe.
13 14i HUNTER:
ES is a uh.
15.
16; i
MEHLER:
Engineering safeguards.
17!
i 18{
HUNTER:
Engineered safeguards actuation.
Okay.
20 MEHLER:
21:l We already had one of those so the boron would have been coming out of the BWST and we would have been fairly highly borated at that time.
23 24 25!
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1.i HUNTER:
On the normal transient that occurred in looking at the time 2l sequence of events, this is just good to talk up if you can follow us.
3 After the plant trips, approximately two minutes into the event, the g
operators had taken the action of starting the second makeup pump, l
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pening the five valve, closing the letdown, and then pressure continued I
Gi to drop and then after two minutes it had initiation of the safeguards 7
system.
And then the operators -- the pressurizer level then recovered 8
and actually went full.
The operators then throttled back on the high g
pressure block and then throttled back on 16 valves and actually 10 throttled back to letdown and a minimum makeup flow and reactor coolant ig pump seal water injection and maximum letdown to try to maintain pres;urizer level.
When you came in, that particular event was over and app rently the makeup pumps, they were down to a minimum makeup 13 and sitting.
Is it normal for the operators to try to throttle the i
high pressurize and safety injection to maintain pressurizer level at 15; 16; i
17!
MEHLER:
They were never in this position before.
19!
HUNTER:
On a normal reactor trip the pressurizer level would go down?
21!
22l l
MEHLER:
Definitely it would go down.
23!
24 25l l
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I i
f 23 1.
HUNTER-In some cases you would get an engineered safeguards initiation?
2.
31 MEHLER:
It has happened and it would recover and you would never go i
solid.
4 i
51 HUNTER:
Would the pressure recover and the level recover?
6 7
MEHLER:
Yes it would.
8 !
b HUNTER:
Now, there was something different in this event?
1g 11:
MEHLER:
Yes.
i 12!
13 HUNTER:
The pressure did not recover but the level did recover?
r 15; MEHLER:
That's correct.
16i l
17!
i HUNTER:
Okay.
Did you discuss with Mike Ross, he really was the 18!
cperations lead that morning, I guess, when he was in and Bill Zewe?
20l MEHLER:
And I believe also that George Kunder was there.
21l I
22 HUNTER:
Did you discuss the low pressure situation with those fellows?
23 24j 25j b
8
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24 t
i 11 MEHLER:
I did not discuss the low -- I noticed the low pressure and I i
2 knew we had to recover the pressure and they also knew it.
l 3l 4
HUNTER:
Okay.
What was your feeling as far as having to recover Sl that pressure?
6i MEHLER:
Well, my true feelings at that particular time when I seen 7
8 the low pressure was either the heaters were not on or we had a leak g'
somewhere.
So I took corrective actions and checked both of them out.
10' HUNTER:
Okay.
And it turned out that isolation of the power operated relief valve was then the first answer.
You indicated that you had 12l problem with the auxiliary boilers.
You ended up steaming to atmosphere
,3l due to... you finally got vacuum or working on the vacuum and that we went 'hrough that sequence.
You indicated that the State calied to c
cease the..
16i 17!
I MEHLER:
Relee.se to the atmosphere.
19!
HUNTER:
Can you clarify who called?
I 21l MEHLER:
I don't know who from the State.
I was just informed.
22!
23l l
HUNTER:
Who informed you?
24i i
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i
25 1:
MEHLER:
Oh my God, there were so many people there at that time.
It i
2!
was -- It had to be someone above me, who I wouldn't know.
I know 3,
that there were a lot people there.
4j 5
HUNTER:
And you were told to stop steaming to atmosphere?
6i 7
MEHLER:
That's correct.
Steaming the atmosphere off of A loop.
I 8l believe this happened at the time when someone put a plane over the g
flume or something and they got a high reading and all of a sudden 10:
they said we were releasing it from A steam generator.
11!
i SINCLAIR:
Let's break here.
The time is 12:12 a.m., May 18,1979.
12 We are going to break at this point to change the tape.
The time is 3
12:13 a. m., May 18,1979.
We are continuing the interview with Mr. Mehler.
15l HUNTER:
Okay, Brian.
We were discessing the ceasing of the atmospheric dumping of steam to the atmosphere from the A steam generator due to 17!
I possible release of radioactivity through that path.
And you indicated 18[
that the State had called and you indicated that you don't know who told you in the control room to stop releasing.
The question that I want to ask is, at that time when the decision was made to go from the atmospheric dumps to the condenser -- the turbine bypass valves that i
dump to the condenser -- did that put you in a bind?
23 24l 25!
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26 1!
MEHLER:
Not really.
It wasn't a big bind, it was just timewise.
3{
Pricr to that we had to reestablish the seals on the turbine and draw i
3{
vacuum and that was time.
4!
HUNTER:
And did you wait to seal your vacuum and it was sealed 5
6i before you changed it over?
I 7l MEHLER:
Yes we did.
What we did is, as soon as we had steam available g
we put the seals back on the turbine.
Once it was back on the turbine al i
Of we started two of the vacuum pumps and started the hauling operation, I
and I believe it was somewhere in the neighborhood of 12 to 15 inches
- 11t, of vacuum.
We started going the bypass valves back to the condenser.
t 13l HUNTER:
Timewise on that, Brian, did it take you...
15 MEHLER:
I would say it took us an hour to an hour and a half to do.
i 17l HUNTER:
And during that time you continued to dump to the atmosphere?
18t 19!
MEHLER:
We had no at M choice.
20:
i 21!
HUNTER:
If you weren't dumping to the atmosphere, where would you 22l remove decay heat?
23l l
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27 f
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MEHLER:
We couldn't have.
I 2!
l 3f HUNTER:
Thank you Brian.
Okay.
You talked in a previous interview 4{
concerning the fact that the buboles in the hot leg could be very 5
large.
And I am not a B&W guy, I am now getting to be a B&W specialist, 6
but you related that to pressurizer level.
Do you recall that particular...?
7 8
MEHLER:
Yeah, I believe you're talking about the intarview with gj 0' Conners, and I told them there about the am.ount.
Normally on a 10 natural cooldown when you depressurize, when the hot legs would go i
11l into the pressurizer; you know, when you depressurize because they are at a higher elevation.
And normally you're at 100 inches in the 12 13 pressurizer at this time and when you depressurize the hot legs going to the pressu,izer you will raise from 100 inches roughly up to 330 inches.
So you're increasing 250 inches in the pressurizer.
15 16i 17l!
HUNTER:
Okay.
Thank you, I didn't have the depressurization part so I was making sure that I understood that.
181 19!
MEHLER:
Yeah, I was relating back to the normal cooling off.
20l t
21!
HUNTER:
Okay, good.
All right, you indicated that the discussions on core flood tank if they occurred, occurred before you were there?
24l 25
(, R S, 2_O 4
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28 I
t 1!
MEHLER:
No.
i 2!
3 HUNTER:
Early in the morning.
And then later on it would be later in 4{
the afternoon that the discussions were held.
I want to make sure 5
that I got that correct.
We were talking about the starting of a q;
reactor coolant pump previous to this and the fact that when you 7
bumped the 2 V pump at approximately 6:54, somewhnre in that time 8
frame, that you had to jumper the K-3 relays.
Could you elahorate on the discussion? Who jumpered them or how you would perform that?
g 10' MEHLER:
Okay.
The electrical department jumpered the K-3 relays.
Basically the K-3 relay is just a permissive relay which has a lot of interlocks associated with it.
It's like a nuc service closed established 3
to it, intermediate closed, oh boy, seal injection, etc.
When all these are satisfied the K-3 reiay would pick up giving you a permissive 15!
signal to start the reactor coolant pump.
17 HUNTER:
Brian, were you'having trouble getting that pump started?
18!
The pump started due to some item not allowing the permissive to be energized?
t 21!
MEHLER:
Yes, one of the interlocks were not picking up; which specific 22 one I couldn't tell you.
231 24l 25 zo
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cm
29 i
i 1!
HUNTER:
After the K-3 relay was jumpered the pump started without...
2!
31 MEHLER:
We bumped the pump, yes.
41 5
HUNTER:
Okay.
Let's move on a little further in the day.
61 MEHLER:
I didn't realize it was that early in the morning we burnped 7
I it.
g t
9!
HUNTER:
Yeah, it may be..
it's a little suprising.
I have two 10 sheets and the two sheets take us from the four o' clock trip out to where we' re going out to 16 hour1.851852e-4 days <br />0.00444 hours <br />2.645503e-5 weeks <br />6.088e-6 months <br />... the point where you get the pump back on and then we consider in our investigation or in our program as 3
being from then on its recovery..that you' re stable.
I just use that as a key.
15!
16:
I MEHLER:
Okay.
17l 18r l
HUNTER:
Okay.
There was a discussion about -- in the afternoon 191 approximately 1:50 or so -- there was a spike in the containment to a high pressure.
21 l
22' MEHLER:
The spike in the containment occurred about 10 of 2.
Some-23 where around 10 of 2 or 2:00.
24 i
25l 4
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30 1!
HUNTER:
Were you in the area when that occurred?
2l 1
3{
MEHLER:
When that occurred I was in the shift supervisor's office.
I What alerted me to it is I noticed the CR0s moving cver towards the Sj makeup pumps and starting to secure them, and that indicated that we i
6 had probably another ES.
And there's two conditions that could have 7
caused it.
Either low pressure, which we were already at, or a high 8
reactor building pressure of four pounds.
9 HUNTER:
Okay, Brian, did you notice that the containment spray pumps 10j I
were on at that time?
12 MEHLER:
Yes I did, I walked out and I,, ant to the left side of the 13 console where the building spray pumps are.
Previous to that I glanced ver the RP pressure indication and it was reading roughly in the 15 neighborhood of one to two pounds.
At that particular point I looked 17l at the spray ump and they were running and I didn't know why, because l
l they should start at 30 pounds.
So we secured the spray pumps because 181
- here was no need to put the sodium hydroxide into the containment all over the equipment.
21j HUNTER:
Okay, Brian.
Did you have the wide range pressure trench 22I recorder available to you for reactor pressure?
23l i
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31 1!
MEHLER:
Oh yes.
2; i
3l HUNTER:
Did you 1cok at that?
4l Sf MEHLER:
Yes, after we secured the spray pumps I went back and checked I
6l the recorders.
And definitely there was a spike aligned straight up.
t 7
It went up to approximately 32 to 33 pounds and it came down in the same line.
g 9t i
HUNTER:
What did this mean to you?
Did it mean anything at that 101 time?
1 11 12 l
MEHLER:
First thought in my mind that someone was screwing with the 13{
14l transmitter.
t 15!
l HUNTER:
Do you know what activity the shift was involved in at the time that today ignition or explosion occurred?
I 18l l
MEHLER:
I didn't know at that particular moment what activities were 19t involved.
Later on I found out.
20:
i 21; HUNTER:
Okay.
And what did you find out later?
22l l
23l MEHLER:
Well, later the only activity that could have caused the i
24!
explosion was some kind of spark because they opened the block valve --
25i l
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32 1t no, no it was not the block valve.
It was the vent valve from the 2
pressurizer to relieve some water.
And that was the only thing that
[
31 could have given us detonation of the hydrogen.
4; HUNTER:
Were they using the vent valve and the block valve on the 5
6i pressurizer? At different times?
l 7
MEHLER:
At different times, yes.
g 91 i
HUNTER:
What's the difference between using a vent valve and a block 10 valve for that activity?
Is is a smaller line?
12; l
MEHLER:
Maybe I screwed up.
13l 14l HUNTER:
Is it a smaller line?
16' MEHLER:
The vent valve is 137 and that is smaller.
I could be wrong 17i in that, it might have been the block.
But I know it was one or the 181 other that they did open at that specific mcment when.
20j HUNTER:
Does the vent valve or block valve are those -- is that a 21 limitorque type motor on it?
Is that electrical motor drive, that 22l type of a motor?
23l 24l 25l
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lj MEHLER:
Yes.
An electromatic has a pilot valve on top of it, which 2;
causes that to open.
The pilot valve actuates first.
f i
3 i, HUNTER:
Okay.
There was some discussion that the ventilation reactor 4j 5j building, refueling building and auxiliary building ventilation was 1
6l restarted at nine o' clock.
Do you recall any discussion about thati MEHLER:
I don't know when it was restarted.
I do know it was running g
i g
later in the day.
I do remember seeing the control switches taped to the "on" position.
10{
11l HUNTER:
Okay.
You don't know when it was turned off or when it was started?
14I MEHLER:
It would have automatically tripped on the high 'adiation 15; 1*v"1s' 6
i 17l HUNTER:
Okay.
Which high radiation levels automatically trip it?
181 19' MEHLER:
Both the reactor buildings.
I am sorry, not the reactor i
building.
Fuel handling buildings, aux building, and probably it 21l l
wculd have also tripped on the stack monitor, probably.
22{
23l HUNTER:
To restart that do you have to reset the actual radiation 24 I
monitor?
25!
.}
P
34 i
llj MEHLER:
Yes, but 2:
I 31 HUNTER:
Or can you bypass it and then restart it?
4j 5
MEHLER:
I don't know right now.
6!
HUNTER:
You made a comment that being in respirators in toc control 7
g room and trying to perform work wasn't a very good situation.
9 MEHLER:
Well, it was hard.
10 11)
HUNTER:
What's difficult about it?
13 MEHLER:
Communications, talking on the phone, answering the page.
14) 15; 16:l HUNTER:
Okay.
And you indicated that after the site emergency was i
declared you ended up moving back into the shift supervisor's area?
18i MEHLER-I basically moved back as soon as we declared tbs site.
19l Bubba Marshall and myself started to set up the tables, yeah.
Isopleths and establishing communication with emergency control station and stationing A0s to answer the phone, etc.
And then by that time Seelinger 22!
of them came in and they moved in; all the engineers showed up and 23 l
they started to do the X/Q's and getting offsite dose reading and 24 that, and the notification was started immediately upon declaring the 25, 1
site emergency.
I
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35 1
HUNTER:
Did you then work in that area the rest of the day?
l 2:
3}
MEHLER:
No, I kind of traveled between that area and getting vacuum i
4 back on the secondary side and getting the K-3 contacts jumpered off.
5 I m re r less was floating wherever I was needed.
6l HUNTER:
Okay.
During the day there were some more key events that 7
8{
At approximately five hours into the event, between nine ccurred.
gj and ten.
The plant pressure was increased and maintained at approxi-mately 2000 pounds cycling around the block valve.
Where you involved 10
}g in that decision to repressurize or discussion?
I 12!
MEHLER:
I don't recall, but I may have.
131 14!
HUNTER:
All right.
The 2-B pump we discussed was bumped and then 15!
they will note that also another pump was bumped.
There was a second pump bumped.
18; MEHLER:
I didn't think we completed two.
20I HUNTER:
Shortly thereafter.
Okay.
Did you in fact.. Yes, just 21!
for 10 seconds the 2-A pump.
Do you recal-1 that occurring and did you have to jumper any K relays at that time?
Or did you jumper all the K 23 relays the first time?
241 25!
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L
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36 lj blEHLER:
I know all the K-3 relays till the end of the whole episode 2
were all jumpered on.
At what specific incident when we jumpered each l
31 indiviudal one, I don't recall.
And I do not recall bumping the i
4{
second reactor coolant pump.
I 5
61 HUNTER:
Okay, fine.
Be surprised when we find out that it really 7
wasn' t bumped, right?
8 MEHLER:
I don't think it was.
g 101 i
SHACKLETON:
3rian?
Could you just briefly for those people who i
11{
I don't understand what the word " bump" means?
12!
i 131 i
MEHLER:
When the reactor coolant pump, which is a 6,000 horsepower 14; l
motor-driven..
9,000?
15:
16; HUNTER:
9,000.
18 MEHLER:
9,000 horsepower motor-driven pump.
The operations group would start the pump for 10 seconds and then turn it right off just to 20!
21l move some water and then in - prior to possibly putting the pump on for a long period of time.
23 SHACKLETON:
Thank you.
24 25l i
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37 i
1 MEHLER:
It's a short run.
I 2l l
3l SHACKLETON:
Okay.
4l 5l HUNTER:
After controlling the reactor system pressure 2,000 pounds
)
6l for a period of time using the block valves, then the system was in 7
fact depressurized to go down on the core flood tank and apparently on g
to decay heat.
Is that a fact?
Sl MEHLER:
That's what they were headed for.
10 11!
HUNTER:
That was the intent.
13 MEHLER:
The intent was to ensure the core was covered by dropping the core flood tanks on and then depressurizing down and going into decay 15i n t removal.
6!
17 I
HUNTER:
Were you involved or did you get into discussions at the 18!
time that you went in on the core flood tanks?
l 20?
MEHLER:
I was toid they were going to do that.
21:,
i 22l l
HUNTER:
Okay.
During this period of time sitting at the core flood 23 tank pressure of about 500 pounds, there is a substantial period of 24, j
hours where the pressure was maintained at approximately at that 5, 6, 25i t
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38 l
1l 700 pound level.
During this time there was some evolution going on 2
trying to get hot leg temperatures back on scale by varying the makeup 3
r the high pressure injection flow paths by injecting thrcugh two 4
loop paths and then altering between two other loop paths and changing Sj the injection f.lew paths.
Where you aware of any of that?
I 61 MEHLER:
No, I was not.
7 I
8' HUNTER:
Okay.
And then later on after Gary Miller had been offsite g
10 and came back onsite, then the plant was repressurized and u.m started the...
I 12, I
MEHLER:
We went solid 13l 14!
HUNTER:
... started t;m reactor coolant pump that evening twice and 16l then they left it on the second time.
That was around -
oh, I'll i
17;l give you the time.
1900 and then started it, and then bumped the pump and then started it and then pressure stabilized and then basically 18j ended up with a bubble in the pressurizer 10:00 that night.
Things 19j
(
generally should have stabilized out at the time.
20!
i 21 I
[ Unidentified Speaker]
Go ahead.
22 23 l
MEHLER:
I always had doubts back at the beginning when you told me we 24I bumped the 2B pump back earlier in the stage, and I really don't 25!
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39 I
i 1
remember bumoing it back in there.
I do not remember bumping that 2{
pump.
I know we were starting oil pumps.
I 3i 4
HUNTER:
Right.
They ran the pump here for 19 minutes, for summary.
of Sf that.
And then there was just a short -- apparently now without being 6
absolutely positive about anything...
i Il g'
MEHLER:
If that graph is correct I was there when that pump was gj running and I do not remember that pump being run.
10l HUNTER:
Okay.
Yeah, okay, that's...
12 MEHLER:
That's where I have my problem.
Because I don't remember them pumps being on until later in the evolution.
That was one of the 14 big things, getting the pump on.
16-HUNTER:
Right. And when these pumps run, by the way, they did not in fact run.
They ran at 100 amps.
They did not in fact pump any water 18 at all.
19i 20j 21;l MEHLER:
I think your time frame is wrong.
22l i
HUNTER:
Pardon? Yeah.
Okay, let me go back and make a couple of 23l points clerr and then I think that will wrap it up.
When you came in 246 in the morning, right away, you -- it became - you became aware right
- c..
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L W
40 1
away that there was steam bubbles in the legs it was obvious to you 2
that they were there.
Was it obvious to the other fellows that were l
3l there?
Did yc' discuss it with them at the time?
i 4l 5
MEHLER:
Yeah, it was obvious to Mike.
I know Mike knew they were i
6i there because we discussed about venting them at that particular time.
7 I didn't really talk to Bill too much.
I HUNTER:
Okay.
During your discussion with Mike or Bill or Ken Bryan, g
10 nybody, did you discuss putting on high pressure injection and taking the system solid at that time?
I 12{
i MEHLER:
No we didn't.
131 1
14!
15l:
HUNTER:
Can you give me a feeling or give us a feeling of why you wouldn't nave considered taking it solid at that time?
{
17 MEHLER:
At that particular time there was no radiation alarms at that time.
I, my own opinion (and I did not realize how much water they dumped out the system) was that we just pumped bubbles in the hot legs.
We were fairly stable.
We finally had pressure recovery and it 21:
was just a matter of venting off the hot legs.
23l j
HUNTER:
Okay.
And once you had established the fact that you had all 24j your pressurizer heaters, did you feel like the pressurizer then would 25j b
i
(
41 i
I lj be available to you and there would be any more problems with the 2;
pressurizer?
l 3l i
4 MEHLER:
I didn't anticipate any more problems with the pressurizer 5
nce we, in my own mind, we established pressurizer heaters and we 6!
were recovering pressure.
To me it was just a matter of being able to 7
get in the containment and venting the pressure off the hot legs and 8
thereby reestablishing the bubble in the pressurizer.
9l HUNTER:
Okay.
One more question Brian.
There was some discussion 10 about the radiation levels in the auxiliary building and there was a discussion concerning leakage paths from vent valves or vent systems, j
cracked diaphragms on diaphragm valves, I assumed that you didn't g
speak of a Sanders type diaphragm or some type diaphragm valves.
And you indicated that in the makeup tank rcom, that the activity levels had been higher than in other rooms.
17\\
MEHLER:
This was into the accident, farther in the days that we 18!
determined this, everyone vas saying "where is it coming from?"
And 19!
we did take a sarrple, I don't know how far, it might have been a week into it.
We took a sample out of the makeup tank ror.? while right 21; after release occurred and the levels were high there.
So this indicates that the release was emanating somewhere within that system, that 23:
j general area.
2' ti 25j
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42 1!
HUNTER:
dhat about any problems in that area prior to the incident?
i 2!
i 3{
MEHLER:
None.
Other than we had problems getting the hydrogen over-4f pressure on the tank through the normal system.
5 61 HUNTER:
Okay.
That was a valve problem, a leak problem?
i 8l MEHLER:
No that was a piping problem.
9
- " Y ""
10j l
11; MEHLER:
It had nothing to do with any of this.
13!
l HUNTER:
Okay.
Was it a design problem? Or a...
15:
MEHLER:
I would say it was a design --
i 17l i
HUNTER:
A small pipe problem or something?
18!
19l i
MEHLER:
I would say it was a design problem.
20l 21l HUNTER:
Okay.
Like a sizing problem or a...
23 l
MEHLER:
If I'm not mistaken I believe the line got water in it and 241 froze.
25!
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43 Ilj HUNTER:
Okay.
Then you were having to add hydrogen manually some i
2:
other method?
I 3l i
4{
MEHLER:
Yeah, we had to put bottles local and run another specific line in there and you had to feed it locally.
c 6
HUNTER:
Okay.
All right, go ahead.
7 8
MEHLER:
That had nothing to do with it.
g l
101 HUNTER:
No I understand that, I just wanted to make sure.
We get I
comments about these areas and...
13
{
MEHLER:
Back to the diaphragm, the specific valve that we were referring i
to is probably the vent valve off the makeup tank which is a diaphragm lo,i operated valve.
And it's... I wouldr,' t say it's identical but it's 17:
almost like the diaphragm valve that we have on miscellaneous evap from Unit 1 which we experienced a lot of problems with on the diaphragms 18l cracking and rur>.uring, etc.
Causing releases.
19t 20t i
l HUNTER:
Okay and that would then be a source of a gas release, if the 21; diaphragm was broken.
23 f;EHLER:
Right.
24l 25!
l o"
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44 1
HUNTER:
Okay.
Do you have any comments or any questions?
Any other 2{
area that you would like to talk about or.
l 31 4
MEHLER:
Well, the only -- maybe one thing I do have.to say.
I do 5
think one of the major problems, I thought was the numerous number of ej phone calls we got during the event which tied people up on the telephone 7
trying to answer questions to different departments and individuals, 8l you know, when they could have been doing their job.
91 10 HUNTER:
Okay.
That meant that you fellows had to be answering phone calls rather than possibly...
11!
12{
MEHLER:
That's correct.
The people that should have been watching 13 g
what was going on, the people with the information had to go back and p ss it on to other people on the telephone rather than really concen-15 16l trating on what they should have been doing.
I 17!
HUNTER:
Okay?
That's it?
18l i
19t MEHLER:
Uh-huh.
20!
l 21l SINCLAIR:
All right.
Mr. Mehler I want to thank you for coming in.
22; l
I realize it's late.
It is now 12:38 a.m.
We are joing to conclude 23l this interview at this point.
.24!
25!
e
I i
i 6
45 I
lj or may have aggravated the incident that occurred at Unit 2 on the 2!
28th?
l 3l 4l TELENK0:
No, I don't.
i 5!
i 6l YUHASL If no one has any other questions at this time, I would like 7
to th ik Mr. Telenko for his cooperation and I don't have anything else.
8 9!
FOSTER:
Ok.
Thank you, Frank.
This interview is concluded at 4:40 10, lli P *-
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