ML19309A253
| ML19309A253 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 03/04/1980 |
| From: | Frampton G, Rogovin M NRC - NRC THREE MILE ISLAND TASK FORCE |
| To: | |
| Shared Package | |
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| References | |
| NUDOCS 8003270141 | |
| Download: ML19309A253 (75) | |
Text
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O EVIDENCE RE QUESTIONS POSED TO CHAIRMAN AHEARNE BY CONGRESSMAN UDALL IN LETTERS OF JANUARY 21 AND FEBRUARY 4, 1980 i
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i Mitchell Rogovin, George T.
Frampton, Jr.
NRC Special Inquiry Group March 4, 1980 l
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l-l 03'M 0
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QUESTION 1, FIRST SET 7
1.
Station Manager Gary Miller has stated that, "The in-cores were reading cnywhere from 2500 or so, and I picked 2500 [;] it could have been higher than that.
But you know, I was looking for a gross indicator and I had it."
What did Mr. Miller believe to be the significance of such temperatures?
Did Mr.
Miller believe on March 28 that during the day portions of the core had been uncovered?
What was Mr. Miller's understanding on March 28 as to the temperatures at which a significant steam-cladding chemical reaction might occur?
(a)
What did Miller believe to be the significance of the in-core temperatures?
Miller's complete answer, from which the quotation referred to in the question is excerpted, is from an IE interview con-ducted on May 7, 1979:
[T]he instrument tech came back and Ivan told me that some read 200 some read 400 and some read 2500 and some didn't read.
Then he explained to me that if they were really hot they would melt and form other junctions and that the calibration wouldn't be good anymore.
So, you know, the bottom line here was that they're hot, they were hot enough that they scared you, as far as what you're looking for, It told me the reason the computer was off scale at 700 degrees.
So I came in at 15 after 7, T was pegging high, T was pegged h
c low.
The in-cores were reading anywhere from 2500 or so, and I picked 2500 it could have been higher than that.
But that, you know, I was looking for a gross indicator and I had it.
Our goal was to maintain HP injection, maintain steaming, core cooling and attempt to go solid.
I know that we were super heated and all that sort of thing, I don't think we tumbled to that kind of lodge [ sic] but we just knew we didn't have a control, we were out of control.
We knew the situation was one we hadn't anticipated too many times here."
(Miller, IE 159, 160, at 56)
The excerpt contained in the question ("I picked 2500")
makes it appear that Miller was testifying that he believed the accuracy of the-2500 degree number.
However, his full answer indicates that Ivan Porter, the lead instrumentation control engineer who reported the readings to Miller, told 1
him that the readings might not be accurate but that Miller did understand from the readings that the core was " hot" enough to be very concerned.
l Thus, while the full answer could be read as an I
admission by Miller that he " picked" 2500 as the actual temperature of the core, Miller's answer taken in context f
suggests that he was telling the IE interviewer that he was
" picking" 2500 as the temperature Porter reported to him, j
though he did not remember precisely what the number was.
All of Miller's other testimony, both testimony given prior l
to this IE interview and testimony given afterwards, is j
consistent only with the second interpretation, as Volume II of the Special Inquiry Group's Report points out.
That i
testimony, which is set forth in detail below, consistently states that Miller did not believe the accuracy of the high i
temperatures for the reasons which Porter gave him, but that he did believe from the readings that the core was
" hot."
Moreover, Miller's testimony that Porter told Miller that Porter did not believe the high readings, and that Miller therefore discounted them himself, is corroborated by similar testimony from Porter, Lee Rogers, Michael Ross and Joe Logan.
(Porter, SIG Depn., 10/30/79, at 5, 11-13, 38; Ross, SIG Depn., 9/18/79, at 23; Rogers, SIG Depn.,
10/11/79, at 29-30; Logan, SIG Depn., 9/12/79, at 14)
In a statement prepared in April 1979 for use in con-
+
grossional testimony, Miller said:
"Incore thermocouples readings were taken on the com-j puter.
The computer put out a ' question mark' which means that we were not in its program, therefore, we sent instru-i mentation personnel to take readings at the penetration, and additionally, to me this indicated that the potential for high readings on the thermocouples were evident.
The read-g ings we got back from the penetration varied from 200. to 2400 to'nothing.
The technical explanation that I was given g
indicated that they were probably hot, that if they were hot, that there could be melting of.the thermocouples and dif-ferent junctions would have been formed and therefore, the temperature indication was not considered reliable on a technical basis, but to me personally, it indicated we cer-tainly had high tergerature readings within the core."
(Miller Statement, 4/79,.at 17-18)
Interrogated en this point in a deposition taken by the Special Inquiry Group, Miller expanded on the reasons why he did not regard the in-core readings as. accurate and on how he did interpret them:
2 1
b
9 "Q.
Mr. Porter, I take it, communicated to you his belief that the readings from the incore thermocouples were not entirely believable?
"A.
My memory is that they were -- the context I evaluated them in, from what I was told, was they were unreliable because some said zero and some said two hundred.
And as I said before, I believe one was over the two thousand mark.
"I was not aware, and I'll say I was aware a month after, that the instrument tech may have, in fact, read out voltage readings for a lot of these, and I don't believe Mr.
Porter even knew of the range of those readings which we have today.
So I -- my memory is that they were not considered reliable.
" Technically they are not normally used.
They are not normally very accurate.
So I would have tended to just --
i to not trust those.
They are not part of the safety systems.
They are not environmentally qualified as far as penetration.
So I would have been led by my own previous experience here in a direction to consider them unreliable given those four readings or five readings.
l "At the same time, I think you must remember that to my memory he had a volt meter installed on a resistance temperature -- an R.T.D., a resistance temperature detector, that was considered an instrument that you could read, even though it was in an environment of steam at that time.
It was on scale.
i "So that would have convinced me that we had a hot temperature.
I didn't consider the incores as being neces-l sary for what I was trying to do at the time."
(Miller, SIG Depn., 9/20/79, at 15-16)
In that same deposition, Miller reiterated the accuracy _
of his April statement as being his best recollection and continued, "if I asked myself today what I remember it was the fact that I accepted their unreliability without really purusing and questioning further.
Then I also said I didn't come back to the item during that period of time.
(Id. at 6) 3
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The specific question posed by Congressman Udall is what Miller believed the " significance" of.the readings to be.
Miller was specifically questioned on this subject in j
both of two separate depositions conducted by the Special Inquiry Group.
In particular Miller was cross-examined as to whether, if he thought the high readings might have been caused by. melting, that information alone would not have j
told him that the temperatures in. core were very high.
The colloquy follows:
n "Q.
My question to you is whether even if you didn't think that the thermocouple readings were reliable in terms
[
of the numbers, whether the high numbers and/or the possibility i
that some of the junctions had melted and so on nevertheless j
convinced you that there were probably some very high tempera-tures in there of some magnitude.
Can you recall that?
I was convinced there was high temperatures in "A.
there.
I didn't quite honestly go back and evaluate the in-I cores like I would today after we've learned an awful lot more about them.
I just think their emphasis in my mind was l
never great.
And when I didn't get reliable information, I i
think I went by them and tried to use other parameters to establish where we were going."
(Miller, SIG Depn., 9/20/79, j
at 17) 1 "Q.
What do you remember about your own interpretation of what those temperatures meant?
Your own reaction to that j
information.
"A.
My own reaction to it was based on I think my pre-conditioned thoughts about it.
I asked for it.
I asked for it more out of my past experience than out of anything I have even seen in these reactors plants.
As I said previously in Unit 1 they are not even available to ask for.
I knew they-were available in Unit 2.
I asked for them.
And I didn't go back and ask a lot of questions about them.
The only reason i
I can come up with that is that it just didn't come up again j
in my mind.
l "In other words, the unreliability part of it, my lack of usage or training in them-didn't make them something that I needed.
They weren't recognized anywhere other than i
~
in my mind from past experience.
I just think that all came together in my mind to cause me not to go back and ask a lot I
of questions that I could ask today quite honestly.- I think j
i
,a
that combined with the number of events I was involved in in that next three to four hours caused me not to go back and ask some more questions and put a different emphasis on the readings.
4 "That plus the knowledge that I had at TH and'TC indications later in the morning didn't cause me to go back and look at temperatures in'the core.
I was convinced from an action standpoint that I would have known of very little else I could have done.
I think that is the way I was think-4 ing.
I was looking for information to base the action we were taking on.
"Q.
At the time you learned the information about the in-core thermocouple temperatures, was there any other pos-sible explanation for the range of readings that Mr. Porter gave you other than that the core in some areas was very much hotter than normal?
"A.
I thought -- I am trying to go back today -- there might have been some discussion about the qualification of other instruments.
By that I mean the fact that I didn't believe they were safety grade and there were conditions in the building we recognized that could have caused them to be in error.
That would have all just helped convince me not
(
to use them."
(Miller, SIG Depn., 10/29/79, at 10-11) r "Q.
Regardless of how precisely accurate you may have-thought the'various instruments were, what I am getting at is when the combination of hot leg temperature indications and the in-core thermocouple temperature indications together i
would have given you any impression of the situation other than that the core was pretty hot, quite a bit hotter than normal.
i "A.
And I am trying to look back at that and I am try-ing not to converse with that with what I know today.
That is very hard to do.
I think if I look at it and try to remember, when I first got to the control room there was no temperature indication. 'None.
TC was offscale low almost.
"We were pumping water in, so that made sense to me.
TL [ sic], there wasn't any.
It was offscale high.
You have to look that I was coming from a place where I'didn't have anything other than that and I think we had steam generator downcomer temperature.
I think what we were looking at throughout the early hours was a way of bounding that situa-tion.
5
s "I don't think we thought about the exact tempera-ture of the core as much as getting some indication so we could see where we were going with that indication.
So I don't remember discussing the in-core for a very long period of time after the initial discussion.
"Q Thinking back about what was in your own mind or what was discussed by you and the other people in the control i
room to whom you were talking, was there ever any indication about the conditions that you were seeing possibly having
. ;?
been caused by the core having been uncovered for a period in the p'ast or_did you yourself think that possibly in some way the core could have been uncovered and then recovered and stayed hot?
Was that something that was in your own mind or was that discussed at any time during the day?
"A.-
As I go back and think about that, it's 6:15 in the morning or whatever time the conference call was, when we asked the question:
Is the block valve closed?
Because of our lack of understanding of the conditions.
And the answer came back yes.
When I got there~at 7:00 in the morn-ing, I still had no understanding that we had had a loss of coolant accident.
Okay?
"Very rapidly thereafter, when we tried to start the pumps and get flow going and get heat removal going we knew there was a void in the system.
Then our concern became what do we do with these conditions in the plant?
Which I or anyone in that group had never envisioned.
I don't think we thought about it from the hours of 4:00 to 7:00 how they got to that point.
"In other words, I can easily think about that today.
But I think my thrust was more to keep water going across the core until we were able to go towards another con-dition of stability.
I didn't have any. question about the' fact we.had high radiation.
I wasn't thinking so much of the core coverage before I got there as much as what do we do..
with the heat now?
I just think that I never had any doubt that the reactor building and the gap activity had been released.
" Dick Dubiel was one of the guys on the phone with the state and he was aware of that, very much aware of the fact we'had released that type of thing.
I don't think I thought about damage to the core in terms of percent as much 4
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,as i knew we had had it.
I knew it had been beyond anything that I would have envisioned before that.
I would have never thought of a general emergency before that other than as a drill.
"I didn't go back and question the exact tempera-ture the core had been to at that time as much as I looked at what action should I be taking now to approach any in-stability from the condition that we analyzed and figured we were'within in that first hour.
Which was no water in 3J,
, various parts'of the system."
(Id. at 14-16)
Atiithe briefing of the NRC Commissioners on January 24,
.~
- " ^~'
1980, on the Special Inquiry Group's Report, a question was asked why the~ Report did not deal with the quotation from Miller's testimony in IE Interview 159, 160.
Some confusion ensued due to our impression that the substance of that testimony, although not the particular quotation, was in fact recounted in the Report.
Subsequently, it has been discovered that the following paragraph contained in the draft of the Report submitted to our word-processing and editing contractor was omitted by a copy-editor before the Report was line-printed for submission to the Commissioners:
"In a written statement prepared in April 1979 by Gary l
Miller with the assistance of others who had been in the control room on March 28, Miller related that 'the readings we got back from the penetration varied from 200 degrees to 2400 degrees to nothing,' and that he personally did not have confidence in the accuracy of the readings.
(State-ment at pp. 17-18)
According to the statement, Miller and Porter discussed what might be the cause of inaccurate read-ings, and Porter explained that the thermocouples or lead wires to them might have melted, causing j unctions to fuse together and produce erroneous voltage readings.
The ' tech-nical explanation' he got, Miller said in the statement, was that the thermocouples were clearly ' hot,' and that that indicated to him that they had high temperatures in the core
~
See also Special Inquiry Group Deposition of Miller, area..
Oct.'29, 1979, at 6.
Porter said in an IE interview on this i
subject that he did not specifically recall discussing with
, Miller whether junctions might have melted, but agreed they
'may have discussed what might affect the readings.'
- Porter, IE Interview No. 324, at 6."
Although this paragraph did not include a citation to IE Interview 159, 160, it did quote Miller's earlier State-ment to the same effect.
The above-quoted paragraph, with 7
an additional citation to IE Interview 159, 160, is being inserted in the final, printed version of Volume II of the Report where it was originally intended to be placed, as the second full paragraph on page 0133 of Part III of Volume II.
(b)
Did Miller believe that the core had been uncovered?
The testimony and statements of Gary Miller on this subject are collected below.
The gist of Miller's testimony in various forums seems to be that it was difficult to deter-mine for sure whether the core was covered and that the subject of possible core uncovery was discussed by his control room " management group" throughout the morning of March 28.
Concern about the high hot leg temperatures and the possibility that high pressure injection water was bypassing the core prompted the group's decision to depressur-ize the system at about 11:30 a.m. on March 28, in order to dump water from the core flood tank into the core if indeed it was not covered, thereby increasing the assurance that the core would be covered.
Pressed on this subject in depositions conducted by the Special Inquiry Group, Miller testified that he really did not focus on whether the core was or was not uncovered as much as he did on what actions had to be taken to restore reliable core cooling.
In his April 1979 Statement, Miller said:
"The command group met periodically throughout the morn-ing and restated our objectives, re-reviewed the emergency plan and communications and our concerns became one of a fear that HPI might be short circuiting the core to the Re-actor Building floor and that possibly the core might not be covered and the potential of having RC-V2 fail (open or slat).
Instruments available did not convince us that water was in fact on the core but my firm decision was to a2 ways maintain high pressure injection.
The group discussed and I directed that we go down in pressure and attempt to use the core flood tanks.to convince ourselves that the core was covered and
,possibly through this mechanism we might get the plant to ~
wards the decay heat mode (Miller Statement, 4/79, at 19-20)
In testimony before Congressman Udall's own Subcommit-tee on May 11, 1979, Miller stated that "from my standpoint during the day, it was hard, starting off with bubbles in those legs, to evaluate whether the core was covered, to 9
8 e
y
. evaluate it physically.
I do not think I ever realized
[that the core was uncovered] until the next day.
Hearings, Part I, p.
195)
In a deposition conducted by staff members of the Presi-dent's Commission, Miller testified as follows.
"Q.
At any point on March 28th, did you believe that the core had'become uncovered?
- v.-
1 a
" A'.
I think we believed there was fuel damage, and it ~
is very hard to remember about core uncoverage.
I don!.t think we thought about events prior to 7 o' clock.
I don't think we discussed, that I remember, core uncoverage prior to us arriving there, but I think we obviously knew there was fuel damage.
"I do not think we were so much worried about how much, but if it was reaching a stable condition in the plant (Miller, Pres. Comm. Depn., 8/7/79, at 271)
Later in the same deposition Miller said:
"I don't think anybody would have thought the core was covered or uncovered.
I think we thought there was fuel damage because of the sequence of events.
I don't think we analyzed in our mind whether core coverage or uncoverage or the amount of fuel damage.
(Id. at 287)
In an IE interview, Miller reiterated that his group spent the morning not being " totally convinced" that the core was covered.
(Miller, IE 158, at 22; see also Miller, IE 159, 160, at 60-61)
In two depositions of Miller by the Special Inquiry Group, he was repeatedly questioned whether he~didn't con.
clude from the high temperatures that the core must be (or must have been) uncovered.
Some of that testimony'is quoted above.in section (a) of the answer to this question.
See-
. Miller, SIG Depn., 9/20/79, at 17; and Miller, SIG Depn.,
10/29/79, at 10-11 and 14-16, quoted above.
Two additional
. portions of. testimony follow:
"Q.
Do you recall on the 28th that hot leg temperature led some people to suspect that the core had been uncovered?
"A.
I don't recall discussion of that.
I am taking that the core had been previously uncovered that morning before
.we-arrived.,
9
O "Q.
No.
The question could be -- it could be 2:00.
You could be looking at the hot leg temperature which was 7-800 degrees.
Somebody could say if it's that hot in the hot leg, the core is uncovered now.
That is what I am getting at.
It doesn't have to be 2:00.
It could be any time during the
- day.
"A.
I don't think we discussed that relative to the core itself.
I do think we discussed whether the high pressure injection was all going on.to the core.
I do think there were people in the group that could hypothesize paths of by,
pass.
But some of it was obviously going in because of the physical, location plus we knew we.were pumping water in at low temperature by looking at TC but that is not in the core.
"I don't think we looked'at that and related it to uncovery at that time.
I think when I talked about core coverage, I talked about it from the standpoint are we sure all the water that is being put in is going on the core since it was just discharging it to the floor and there could be bypass paths postulated anyway by some members of that group.
"Q.
So you remember concerns about bypass paths and whether the flow path was through the core or around some other path.
You don't remember a concern that said, hey, the TL [ sic] is telling me the core is dry.
"A.
No.
In fact, one of the -- at least our reasoning factors for going towards core flood was the discussion that if we could get enough Delta pressure between the core flood and the reactor we could convince ourselves there wasn't a void occurring in the core throughout the morning, I think.
I don!t think we thought back'that it has been voided."
(Miller, SIG Depn., 10/29/79, at 38-39)
"Q.
In a prior I.
& E.
interview you mentioned that, as you recall it, the group _that you were consulting with spent a good part of the morning not totally convinced that the core-was completely covered.
"A.
(Affirmative nod.)
"Q.
Is'that an accurate characterization of your state of mind?
"A.
I think as we met we were trying to give ourselves the absolute assurance that we were covering the core, and I think that we understood that there was steam in a lot of the e
4 10 4
' system.
There are not very many indicators of core level that you are taught about.
And I think, therefore, there were --
we were questioning ourselves as to whether high pressure in-jection was, in fact, going on the core.
"And I think there were members of the group that were just not totally convinced that all of it was going on the. core.
And that was discussed in probably, I think, most of the meetings.
r "Q.
Did you ever put together the high or very high temperatures that might be in portions of the core with this concern about possible uncovery or a possible state of steam
' heat removal rather than water contact with the fuel elements?
"A.
I don't remember discussing boiling in the core.
I do remember us discussing, assuring that.the coverage was there over the core and that we were -- we were concerned about the high temperatures and the steam environment that we were under in most of the system.
"And we didn't -- I don't think we thought back about whether there had been uncoverage'as much as we thought is it still totally covered.
We didn't discuss boiling water in the core that I remember.
"Q.
I think, if not you, other members of that group have testified before that periodically over 'the morning you got together and said in substance, okay, now do we all think the core is covered.
Do you remember that?
"A.
I remember.
I think I remember the core coverage was probably the biggest thing I could -- you know, the single issue among the group.
Other than the emergency plan, which we -- which we took on each time.
"Q.
But you were definitely not convinced that you had flow through the core; that is, you thought that the high pressure injection water might be by-passing the core or parts of the core?
"A.
We discussed that that could be done.
I think the temperature _ indication on the cold indications told us that some of it was going in.
And I think we discussed that.
Okay.
I think we had no way of assuring ourselves what the level in the system was."
'(Miller, SIG Depn., 9/20/79, at 17-19) 11 L_
(c)
Miller's understanding re steam-cladding reaction
~
temperatures.
In a deposition conducted by the Special Inquiry Group, Miller was specifically asked a series of questions concern-ing his awareness of temperature limits for fuel cladding.
His answers indicated that he had been aware in the past of limits in the range of 2300 or'2400 degrees, but that he did not put these limits together in his own mind with the in-core thermocouple temperatures. reported to him on March 28.
~.
The testimony is as follows:
"Q.
With respect to those core thermocouple readings, were you aware of the 2200 degree limit in the ECCS regula-tions on calculated peak clad temperature?
"A.
I might have at sometime been aware of the interim criteria of like 23-or 2400.
I don't remember thinking of that number at that time in the morning.
I would not have been unaware cf that number in some reading I had done pre-
- viously.
"Q.
You were aware of that kind of limit.
I think you just quoted the interim acceptance criteria, which were a little higher.
The final number was 2200.
But you didn't connect that with the 2400 degree reading on that morning, is that right?
"A.
I didn't connect that with the zero to 200 or --
I didn't connect that with the series of readings.
I think if someone came back and said to me 2400 degrees, 2300, if I got 4 or 5 consistent readings or 50 readings, it would have made a difference in my discussion of that.
I didn't at the, time go much beyond reliability discussion of the instrument.
I didn't'believe it.
"MR. WILSON:
I believe in your question you improperly stated his response. 4You said he was aware of it whereas he said he might have bqsn aware of it.
Am I correctly stating your response to his question?
"THE WITNESS:
I was aware at one time in my life of the interim acceptance criteria.
That was not a discussion point or point that came to my mind that morning.
"MR. ALLISON:
Thank you, Mr. Wilson.
12
+
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"BY MR. ALLISON:
"Q.
What_was your impression of the reason'for that limit?
That~ temperature limit in the ECCS' criteria.
"A.
I believe my impression at one time was that it was.related to the cladding.
It could also be relatedito the -- let me think a second -- my memory of that day is that that-was the temperature you should not exceed in the ECCS analysis on the fuel.
I don't know that I could remember
' what that relates to directly as far as fuel melt yersus re-action of the cladding and so forth.
But I do remember that was the criterion from the ECCS standpoint that you couldn't see on accident analysis."
(Miller, SIG Depn., 10/29/79, at 49-50).
e 0
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QUESTION 2, FIRST SET "2.
Is Mr. John Flint correct in his recollection that, 'These [in-core] temperatures were monitored for the rest of the day [ March 28] to follow what was happening to the core?'"
John Flint, a Babcock & Wilcox start-up engineer, was in the Unit 2. control room during the day on March 28, reporting to Lee Rogers, the B&W site representative.
During an early IE interview on April 23, 1979, he testified:
"During this portion of time we ~were periodically printing out the RTD's of the incore themocouples and following the temperatures in the core.
When we first started dumping
,them out.many of them had question marks, which indicated they were above their normal scale of 700* not printing out
" bad" which would indicate that they had failed.
Over the next few hours these thermocouples gradually came back on scale we were recovered more and more of them and towards late afternoon I believe we had most of them indicating on scale."
(Flint, IE 58, 59, at 8.)
Instrumentation computer printouts show that in-core thermocouple readings were requested by someone in the control room on at least three occasions during the day after'.the original requests (made by Ivan Porter) at about Bi30 a.m.
that morning.
In a follow-up IE interview, Flint was questioned in considerably more detail about his earlier testimony.
In response to this questioning Flint testified, in substance, that he himself continued to request in-core thermocouple temperatures from the computer on a number of occasions throughout the day, until he left that evening; that ori-ginally most were off-scale high; that Flint was not aware of the readings taken off the wires earlier; that Flint was the one who advised others that he would be looking at the in-core temperatures; that Lee Rogers either suggested he do this or left it up to him; and that he (Flint) did not know whether Rogers ' told Miller or others that Flint would.be doing this.
The testimony is as follows:
"Q.
Now, I believe also in yo'ur previous discussions with us, you said that you had requested incore temperatures.
"A.
That is correct.
"Q.
About what time of day would that have been?
"A.
I believe I started recording them at approximately 09 30, - and continued on.until I lef t at 2300 that evening.
14
"Q.
Now, you would be requesting these as like a data. output from the computer?
"A.
That is correct.
"Q.
Punching them out.
"A.
Yes.
"Q.
Would these be as a summary or would they be again point by point?
"A..
Depending on which group I called up, it would either be ~ a point by point or a summary.
I could be a com-
. bination of the two, depending on what I was looking at, at the time.
"Q.
Did you plot these on a core map?
"A.
No, I did not.
"Q.
What use were you making of this data?
"A.
On the incores was a way to see how many came down on-scale.
When I first started looking at them, most of them were off-scale high.
(Flint, IE 32 3, at 25-2 7. )
"Q.
Did you make a recommendation'to anyone specifically to monitor the incore thermocouples?
"A.
I advised them that I would be monitoring the incore thermocouples.
And I believe that Ivan Porter was also look-ing at them.
And somebody else later on was looking at the incores at the time that I first came in the Control Room, although stated that I would follow the incore temperatures.
"Q.
I believe in our previous interview with you though, that you stated that you weren't aware that anybody else was monitoring them, before you got them.
"A.
That's right.
When I first came into the Control Room, I was. not aware and did not' learn for quite some time that somebody.else had already-been looking at the incore temperatures.
"Q.
When-did you first find out that somebody.had?
- A. _It was weeks.
When I found out that they had gone1 down to1the Cable. Spreading Room, and'had actually gone down.
They had' disconnected and looked at the temperatures down there in the Cable Spreading Room.
15
"Q.
Do you recall who you made the recommendation,to,
. to monitor the incore thermocouples?
When you did start that work.
"A.
Lee Rogers.
Q.
Do you know whether Lee communicated that to Gary Miller or Tnyone else there?
"A.
No, I do not.
7 "Q.
What did. Lee feel about doing that?
Did he feel that was a good idea, or did he say go ahead do it?
"A.
He left it up to my judgment, since that was the area I was following." (Id. at 34-36)
There appears to be no reason to question Flint's testimony that he periodically called up the incore thermo-couple temperatures on the instrumentation computer, as he
'has said he did.
In this connection, Flint's supervisor, Lee Rogers, has testified that he has no recollection of incore thermocouple temperatures being mentioned subsequent to Porter's original report to Gary Miller in which the accuracy of the high read-ings was questioned.
(Rogers, SIG Depn.,' 10/11/79, at 54)
We found no evidence that any in-core thermocouple data of any kind was reported by Rogers during the day to his own management in Lynchburg, Virginia.
Both Miller and Porter have testified that they do not recall returning to the ques-tion of in-core thermocouple temperatures again during the day or discussing them, after Porter's first report, because they did not believe these instruments could yield them use-
'ful information.
(Miller, SIG Depn., 10/29/79, at 9-11; Porter, SIG Depn., 10/30/79, at 13-17) 4
.16
QUESTIONS 3 AND 4, FIRST SET "3.
Which of the TMI supervisors present at the plant on March 28 believed some of the fuel rods r
had been cooled primarily by steam for portions of the period between 6:00 a.m. and 8:00 p.m. on March 28?
What was the understanding of these supervisors on March 28 as to the gladding temper-ature at which a significant steam-cladding chemical reaction might occur?
[,
"4.
How does each of the TMI supervisors, who was present on March 28 and who did not believe that portions of the core had~been uncovered, interpret the hot-leg temperature data indicating superheated conditions?"
In depositions conducted by the Special Inquiry Group, supervisors who were present in the Unit 2 control room on March 28 were specifically interrogated about whether they believed the core had been uncovered and how they interpreted the observed high hot leg temperatures.
To answer question 3 precisely as it is posed, none of these supervisors, except George Kunder, apparently believed, according to their testimony, that some of the core had been cooled "primarily by steam" during part of the day.
- However, the prevailing attitude, at least during the morning of March 28, appears to have been one of doubt as to whether the operators could be assured that the core was being covered' and adequately cooled.
The testimony of the various individ-uals questioned is set forth below.
Gary Miller As, pointed out above in the answer to Question 1, First Set, Gary Miller has repeatedly testified that during the morn-ing of March 28, it was difficult to determine if the core was in fact covered, that members of his " management group" were concerned about whether they could be certain the core was in fact completely covered, and that " core uncovery" was.a major issue periodically considered.during the morning.
(Miller, SIG Depn., 9/20/79, at 17-20)
Asked directly whe-ther the in-core thermocouple readings reported to him, to-gether with the hot leg temperatures, led him to conclude that the core was uncovered or that the prigary mode of core 17 m
~
--M--
. cooling was by steaming, Miller replied that he was " con-cerned" about the high temperatures and the " steam environ-ment that we were under in most of the system."
(Id. at 18)
According to Miller, it was the group's concern about assuring themselves that the core was indeed covered, and specifically the fear that high pressure injection water might be bypassing the core rather than flowing through it, that led to the decision at about 11:30 a.m. on March 28 to depressurize the system in order to dump water onto the core from the core flood tanks.
(Miller, SIG Depn., 10/20/79, at 38-39; see also Miller, April 1979 Statement, at 19; and Miller, Pres. Commn. Depn., 8/7/79, at 271)
Most of the other supervisors whose testimony is des-cribed below also recalled that this was the general attitude of the group.
Asked specifically about whether the hot leg temperatures were discussed by the group during the morning, Miller testi-fied that the temperatures were discussed during these meetings, particularly with respect to the decision whether to depressur-ize the' system and whether to bias high pressure injection flow to one leg in order to attempt to increase flow through 10/29/ 9, at 36) 7 the system.
(Miller, SIG Depn.,
During that same deposition, Miller was interrogated as to his own understanding of the meaning of the hot leg temper-atures:
"Q.
There were several meetings of your management group that day.
Do you think the hot leg temperatures were discussed during those meetings?
" A..
In the group meetings I discussed?
"Q.
Right.
"A.
Yes, sir.
I think those were discussed along with the void in the system and I think they were discussed especially when we came down towards core flood and later on in the after-noon I believe we even shifted the amount of water going is
~
various.high pressure injection legs because of the response of the high temperature instrument.
"Q.
What did the hot leg temperatures mean to you?
What did you interpret them to mean?
18
t "A.
I think people in the group discussed those through-out the morning.
I think they were -- initially I-don't think they indicated that much until we analyzed them very closely because we also started to pump and were convinced there was a void in the hot legs.
Somewhere in the morning, maybe based
~
on Lee Rogers's thrust, there must have been discussion of a superheated condition but as of today I can't remember that.
I do know we charged the loops all morning and we went -- we discussed coolant valves as opposed to throttling with block valves and that kind of discussion.
"And were continuously discharging water to the floor
.to maintain the flow rate.
The pressure was just steady.
"Q.
Is it fair to say the hot leg temperatures meant steam in the loops to you?
"A.
It meant steam in the loops and confirmatory with the reactor coolant pump start and the 100 amp indication'and that sort of thing.
I think sometime later in the morning we may have discussed steam conditions when we got into the core flood type discussion because we were aware we weren't getting anywhere by charging the plant.
"Q.
So you think perhaps later in the morning the steam conditions were discussed.
"A.
I think that's true and I base'that on the fact that I think Lee Rogers and his people may have brought that I don't think that'made much difference from an action up.
standpoint.
I think we talked about going against the ccolant reliefs but that is very hard to specifically remember.
"The biggest driving reason to go down in the pressure I believe was a step down towards more stability and also-the water discharge, the possibility of the electromatic failing --
not that but the block valve for the electromatic which has a valve that fails when you open and close and we were cycling it, that is when I think that discussion would have occurred.
That plus I had a concern for the amount of water because wo were not short of water but we were discharging a significant amount of borated water storage tank.
~"Q.
Do you recall on the 28th that hot leg temperature led'some people to suspect that the core had been uncovered?
D 19
1 "A.
I don't recall discussion of that.
I am taking that I
the core had been previously uncovered that morning before i
we arrived, j
"Q.
No.
The question could be--- it could be 2:00.
You could be looking at the hot leg temperature which was 7-800 degrees.
Somebody could say if it's that hot in the hot leg, the core is. uncovered now.
That is what I am getting at.
It doesn't have to be 2:00.
It could be any time during the day.
"A.' I~ don't think we discussed.that relative to the core itself.
I do think we discussed whether the high pressure injection was all going on to the core.
I do think there were people in the group that could hypothesize paths of bypass.
l But some of it was obviously going in because of the physical location plus we knew we were pumpting water in at low tempera-ture by looking at TC but that is not in the core.
"I don't think we look at that and related it to mi-covery at that time.
I think when I. talked about core coverage, I talked about it from the standpoint are we sure all the water that is being put in is going on the core since it was just discharging it to the floor and there could be bypass paths postulated anyway by some members of that group.
{
i "Q._ So you remember concerns about bypass paths and 1
whether the flow path was through the core or around some other path.
You don't remember a concern that said, hey, the l
TL is telling me the core is dry.
l "A.
No, in fact, one of the -- at least our reasoning factors for going towards core. flood was the discussion.that if we could get enough Delta pressure between the core flood.
and the reactor we could convince ouselves there wasn't a void occurring in the core throughout the morning,'I think.
I don't think we thought baux that it has been voided."
Michael Ross
'In a Special Inquiry Group: deposition focusing on this issue, Rossi Miller's OperationscSupervisor,-testified:that while Miller's management group was'" concerned that the pos-sibility" of core'uncovery existed, he'himse1f did not focus-on whether that had1 happened:
9 9
20 O
6.
e-
~
g "Ross:
I think we discussed the fact that high pressure
' injection had been off for some time or throttled back.
I don't think we ever related it to fully uncovering the core that early.
"We were concerned that the possibility existed. In our own minds we had a concern that we had to do something.
We knew we_had some problem.
We had radiation monitor alarms.
We knew we had fail fuel of some sort, and the seriousness of it was not known, of course.
"Q.
In.your own mind, did you entertain the possibility that the core had been partially uncovered for a period of time?
"Ross:
No, I guess I really didn't.
I was kind of con-cerned about it particularly as the day went on but I don't think I ever said, " Hey, that thing could have been uncovered,"
definitely.
"Q.
What were the things that kept you from considering that as a realistic possibility?
Was it anything other than the pressurizer le,el continuing to be high, if you can recall?
"Ross:
Being honest, we just never had full time to sit back and analyze the whole situation very closely and very methodically.
I think that is the only thing that prevented us from making that look-see effort."
(Ross, SIG Depn., 9/18/79, at 12)
Questioned further about the in-core thermocouple temper-atures reported by Ivan Miller to Gary porter, Ross said that he recalled the readings being "anywhere from zero to 20 to 200 to 2000.
Basically, the reading being not taken on a serious vein because there were many readings questionable and low'than there were any that showed a high temperature.
They determined,.at least at the time, that the readings were inconclusive."
(Id. at 23)
Ross has testified, however, that like Miller, he knew these readings meant that the core was
" hot."
(Ross, IE 81, 82, at 42)
Asked whether those read-ings, if believed, would not have led one to conclude that the core was being cooled by steam, Ross answered that they would have:
"Q.
When you say it is a little hard to think about'
~
.what you would have done differently had evGrybody believed-those high temperatures were all accurate, wouldn't the.high temperatures have possibly told you that you might still.have
.i e
l.
21 l
f
~
some part of the core that wasn't covered or that was being
' steamed rather than covered with liquid?
"A It may have.
It may have led you to think that well,-it would have.
"Q.
I know this is a hypothetical question, but if you had known that during the period of time when you were cycling the valve,.would that have -- is there a clear alternative strategy the.t you might have perceived to try to get more in-ventory into the core other than what you were doing?
"A.
No.
You just make up all that you can and you got' a choice', either let the system go solid or open a hole some place and remove energy and water and that is basically what' you are doing.
I don't think it would have changed the strategy here (indicating).
It may have changed the strategy down here (indicating).
"Q.
When you say "it might have changed the strategy down here," you are pointing to the period of time when you blew down the system after 11:30 in the morning and tried to get lower pressure?
"A.
Yes.
We may have considered that a lot differently (Ross, SIG Depn., 9/18/79, at 26)
George Kunder Kunder, the Superintendent-Technical Support for Unit 2, probably cane closer in his testimony than any other control room supervisor to acknowledging a belief in steam cooling.
~
Kunder stated both in a previous IE interview and in a depo-sitior conducted by the Special Inquiry Group that he was concerned about high pressure injection water-bypassing the core based on the failure of hot leg temperatures to show any progressive decrease.
In the following. colloquy, Kunder ^
described _his concept of how the system might be behaving:
I was concerned, is there a possibility for. that kind 4
of thing to occur.
Could some water be getting into.the: core and flashing to_ steam'with such violence:that it was creating
, a, pressure grade across the water rather than through the core in a bypass fashion around it.
4 JB 4
22
"It was due to the fact that there was no clear evidence of exactly what was occurring in the core.
I was scratching for some sort of concept of what might be happening.
"Q Was there any discussion in the caucus meetings about saturation conditions or did you yourself consider whether voids were continuing to be created during this period of time?
I am talking now before noon on the 28th.
"A.
I myself felt that we had continued to have voids -
in the system.
I know one of my pet concerns, which I think was a more serious concern'on my part than any of the other concerns that were being considered, was the fact that we could be concentrating boric acid in the core, because any water that is getting in, if it is getting in, it is flashing to steam.and that is a cooling mode at that point in time.
"Of course, we didn't have any level indication so you couldn't be certain what the level of coolant would be in the core.
I assumed that there is a.significant possibility that this boiling action that could be occurring would be con-centrating the boric acid in the core.
I was becoming worried that after some period of time, which quantitatively I couldn't define, we could actually form a slurry boric acid which pos-sibly could impede per the cooling [ sic).
"I guess in the morning that was -- that issue along with the issue of how do I assure that I am indeed cooling-the core were the major ones in my mind.
"Q.
Was there ever anxiety about the core actually being uncovered during this period of time?
"A.
I believe it would be safe to say there was some anxiety along that line, but intuitively I believe I always-felt the core was' covered or at least being cooled sufficiently to stop any increase in core temperatures or increase in the
~
voiding that we may have experienced.
We couldn't prove it.
There were no' indications to prove that we were cooling the core effectively.
"In'that regard there was anxiety about guaranteeing that if we had.the core cooled and verifying something that we intuitively felt was occurring, either'through direct cool-
~
ing with water or by some steaming that was, of course, removing-heat.
23' 9
g
"Q.
How did the high hot leg temperatures figure in this evaluation?
"A.
We were looking desperately for those temperatures to show a der:rease and that would point towards an improvement in our condizion.
"hroughout a good portion of 'the morning and I guess into :he afternoon, those temperatures were not respond-ing as we were hoping them to respond in order to use those as a basis for suggesting core cooling was improving.
"Q.
Were the hot leg temperatures disbelieved?
"A.
No, I never disbelieved the hot leg temperatures.
I thought they were about 800 degrees, in that range.
"I think that we had believed in those 'occause we had more than one RTD telling us the same information.
"Q.
So what you are saying is the hot leg temperatuyes showed you that you might not be getting out of the core cool-ing with this particular mode of cooling?
"A.
At the time I viewed the hot leg temperatures as being representative of voiding steam in the core, I visualized the reactor coolant system as being steam bound in the upper section of the core and hot legs themselves.
Since we were relieving steam through the electromatic relief valve at various portions of time in the morning and afternoon, that we were removing some heat.
We could not confirm from those indica-tions whether that removal of heat was adequate to keep the core safely cooled or improve the cooling of the core.
We did not have indications that would conclusively confirm that the core was covered in its entirety.
"I believe that there was some possibility that we were having steaming in the core which was contributing to some voiding and I guess in a technical sense you could say.
'he core was not fully covered but it was being cooled to some t
extent..That is the way I think I perceived things at that time."
(Kunder,.SIG Depn.,.9/18/79, at 52-55)
In sum, it appears that Kunder conceived that there was some steam binding in the top of the core area and~therefore some steam cooling, but that-there was always sufficient cooling to keep.the core temperature from increasing.
24
a
~
=-.u a
., +
e J
. Lee Rogers Although. George Kunder testified that he never dis-
. believed the hot leg temperature readings being recorded by the RTD's on the hot legs, others in the control room have testified that there was doubt as to whether these readings were reliable, and that Miller's. management group discussed this question.
Lee Rogers, the senior Babcock & Wilcox representative on site, told the Special' Inquiry Group that at first "we weren't at all sure that the RTDs were actually going to give us an ticcurate indication of the temperature.
So it was not accepted that we knew enough tx) call them accurate indica-tions (Rogers, SIG Depn., 10/11/79, at 23)
Examined at some length on this conclusion (id. at 23-29), Rogers stated that the RTDs were designed to give an accurate reading of water temperature and were not intended for steam flow.
Asked why a readirg in steam phase would not at least provide a "ballpark i ndication" of the steam's temperature, Rogers re-plied:
"Yau're asking me to evaluate the question tnat was raised.
all I'm saying,is that the question was brought
..nobody would have had information available to-answer up.
at tha+. point of time.'
(Id. at 24-25)
Rogers canceded that as the day wore on, however, it became apparent that these temperatures were more or less accurate.
(Id. at 28-29)
Rogers also testified that he recalled the in-core.thermo-couple temperatures being reported:
"Q.
Do you remember at.that time a second caucus meet-ing, whether you had gotten any information about the:in-core thermocouples?
"A.
I think that that meeting was where we first'got.
information fed into us, yes.
"Q.'
Okay, what'do you-re.411 about what you learned?
"A.
Statements were being made by the person that-was-passing that information along that we had had temperature indications ~off of the in-core thermocouples which varied from very low-to very~high.
"And.on the. computer: output, it was beyond the range of the program indication.
9 25-
"But when read at the junctions of the inputs from the thermocouples and converted to actual temperatures, it was as high as 2400 or in that area on some thermocouples.
With the scattering of information that we had then, it seemed to be another area of the information -- the information was confusing in that it covered such a broad area.
"And one question had become raised:
that do we know they are really telling us the true temperature indica-tion?
It merely had been raised as a question.
"And I don't think anybody tried to evaluate it much beyond that.
"Q.
Was it your sense that the high numbers were dis-believed or was the question of their accuracy just sort of tossed out?
"A.
I believe that's the tone of it.
T "Q.
The latter?
"A.
Is that really an accurate indication of what the temperature may be in there?
"It wasn't -- it wasn't much more than that, I would think, just questions."
(Id. at 29-30).
Nevertheless, when asked whether the hot leg and in-core temperatures would not have led to an inevitable conclusion that boiling or steam cooling was occurring in the core, Rogers did not agree with this conclusion:
"Q.
But is there any way that that steam -- that steam bubbles could have remained in the' hot leg at tempera-tures anywhere near that temperature throughout the day without continuing generation of the heat by the core, as a result of some boiling?
"A.
Well, if you assume that you have limited or next to no heat removal capability, especially on the B-loop where we had bottled up the steam generator -- we had no atmospheric dump capability taking place at all during the day on the B side.
"We had no indication of any-natural circulation because of the_ steam condition.
You wo 21dn't expect to find
~
it anyway.
-26
f -
"It would be fairly easy to say that the tempera-tures could stay very high; once they had become created in there, it would stay there with no capability of removing it, except the ambient loss at that time were --
"Q.
Small --
"A.
-- small heat transfer capability, yes.
The ambient losses would be a very slow change in temperature.
"Q.
So it would be possible, as far as you can see, to have a continuing condition of super heat or at least
'right at sat'uration in the loops and still be satisfactorily
' cooling the core?
"A.
Especially because of the geographic layout of the loops; it's a. natural trap."
(Id. at 26-27)
"Q.
If those temperatures, the high temperatures were anywhere near accurate, is there any other conclusion that you could draw, other than you had or recently had had steam blanketing or steam bubbles in the core?
"Were there other explanations for such a high temperature?
"A.
I'm not sure that anyone would have immediately.come to a conclusion that we had had a loss 6f water level in the core area with that inclination.[ sic].
"Maybe someone would, but they did not bring it up; it would be more or less of a higher temperature indication, if it was to be believed.
"It would not necessarily ar.tomatically follow :
intuitively to everyone that we had '.ost water level in the Core.
"Let_me say that from the thrust of practically.
everything at that point in-time that everything beyond that was.to get the plant into a stable' condition:and not too
~
-much to go:back and evaluate the sequence of. events as to how we got there.'
' ItLwas:
let's get1[this thing) under normal control and indications'so that we know where we'are, and.
thatjwas our major thrust'throughout the day.
27 o
+
t "Q.
I guess my question was directed to whether that
, information, temperature information, if believed, would put more urgency on the need to make sure that the core was covered or at least -- not only covered -- but liquid was actually coming in contact with the fuel' elements.
"A.
That was part of our actions; we were reaching conclusions, at least, that, as I. understood it, that we were keeping water in the system with the direction from Mr.
Miller such that HPI would not be secured without my knowledge.
"Q.
You recall that instruction?
"A.
I do.
"Q.
Do you know why that instruction was delivered?
"A.
No.
It was merely a statement that Mr. Miller made and no one disagreed with it.
"Q.
That was as a result of -- or during the second caucus meeting you think?
"A.
Yes, I feel that was the time I heard that.
"Q.
And it was a result of that' discussion that it was decided to get the pressure up and put more water into the system?
"A.
Yes."
(Id. at 30-32)
William Zewe Zewe, the Shift Supervisor on duty when the accident began at 4 a.m.,
also testified'that the decision to depressur-ize the system at 11:30 a.m. was made because "we weren't cer-tain that we weren't bypassing the core somehow with our high pressure injection water."
(Zewe, SIG_Depn., 9/11/79, at 97)
While Zewe agreed that he was' aware.of superheat conditions, he als'o testified that he never believed the core had been uncovered at any time during the day on March 28.
(Id. at 109-110)
~
Zewe, like Rogers, apparently believed that steam could
~
remain bound in the. hot legs at superheated temperatures with-out indicating core uncovery:
~
28-9 4
" WITNESS ZEWE:
See, we perceived then that the area of the RTDs at the hot legs -- that comes out of.the reactor, makes like a candy cane effect.
After it turns and comes down before the steam generator is where you have your RTD.
"The high temperatures we felt that that was just the steam that was in the loops and, once later on in the day we finally got some cown-scale indication, we felt we were then forcing water over the candy cane or over the hot leg past the RTD cooling it off and showing that were once at some minimal flow, if you will, or some water movement past that RTD, which was more indications that we had less voids than what we had before, at least in that loop."
(Id. at 150)
Both Zewe and control room operator Ed Frederick, how-ever, may have based their view at least in part on skepticism about the accuracy of the hot leg readings, at least insofar as those readings might be indicative of what was happening in the core itself.
(Neither was aware of the in-core readinca given to Miller by Porter.
Zewe, et al., SIG Depn., 9/11/79,
,at 100-104, 265-267)
The two argued vigorously in a depo-sition taken by the Special Inquiry Group that the RTD read-ings in the hot legs were dependent upon water flow through the system and that without the representative flow, they would not give accurate information about the temperature "two inches away."
(Id. at 100-104)
Zewe reiterated that he did not believe the hot leg temperatures gave useful in-formation about core conditione.
(Id. at'99)
Ivan Porter Porter, the lead instrumentation engineer for Unit 2, testified in a Special Inquiry Group deposition that while he did not believe the accuracy of the four or five in-core
' thermocouple readings he reported to Gary ~ Miller, he "was more concerned, if you want to talk about core covering, just based on the parameters we had in the control. room.
We already knew that the hot leg temperatures were off-scale.
We tried to run an RC pump and it didn't. pump water."
(Porter,.SIG Depn., 10/30/79, at 18)
As pointed out above in answer'to Question One, First Set, Porter was the engineer to whom several instrument technicians made statements that the core must be uncovered; however, Porter does not recall discussing this matter with Gary Miller, or repeating their-comments to him, nor does Miller.
29
' There is nothing in Porter's testimony or prior state-
,ments indicating.that he, like Zewe and Frederick, tended
~ to doubt the accuracy of the hot leg RTD temperature indica-tions.
Asked.about whether he thought the core might have been uncovered, Porter answered, basically, that that was of less concern to him than trying to get assurance of adequate core cooling:
" QUESTION:
At the time just before you went down on March 28, 8:00 o' clock in the morning, to take the tl rmo-couple readings, do you have any feelings as to whether the core had been uncovered or was uncovered?
"THE WITNESS:
I guess I think my feeling was that maybe it was difficult to understanding, but it was not the thermo-r couples, the RTDs, how we had water, say, between the RTDs
~
and the core and still had those readings.
The other thing I couldn't reconcile in my mind was how we had 700 or say.700 degrees, essentially a super-heated condition, and a non-flow condition either.
I have always been used to associating super-heated steam with high flow conditions.
"You just can't fill the container with super-heated steam and set it down and it stays super-heated steam.
"Whatever concerns I had, I think, we based more on the RTD readings up on the hot leg than-they were on what the thermocouples were saying then or what information I got when I went down there.
"I guess I really don't think, in my mind, that the number one consideration was whether the core was uncovered at that point or whether it had been uncovered.
The number' one consideration was getting cooling on the core and making
.sure that we were going in the right direction.
"I don't think the number one thing that I was running around thinking was, is the core uncovered or isn't the core uncovered.
I'm not sure that if it was, in fact, covered but we didn't have flow and couldn't get flow that I would have been much more comfortable than I would knowing that maybe it was partially uncovered.
I don't recall, you know, I'm a hundred percent. happy if the core is covered and I'm a hundred percent unhappy if the core is, uncovered.
30 m.
"I'm trying to get control of the plant and get it
~
in a stable cooling-down condition, that was really what the 4
objective 1was._ We weren't -- well, we -- I or nobody that I was with was sitting-back as an analysis group trying to decide if.the core was uncovered.
We went on about ten dif-ferent topics in a period of an hour or an hour and a half or l
something.
"I just can'.t answer that question.
I don't remember at.8:00'o' clock:in the' morning that the number one considera-tion was, is the core uncovered.or covered.
I was trying to -
get the plant headed in the'right direction.
l "BY MR. FRAMPTON:
"Q.
Leaving aside the in-core thermocouple temperatures altogether, it seems to me what you were saying is that-from.
the hot leg temperatures and the steam in the hot legs that you drew a conclusion.that you had a pretty serious problem with core cooling, is that fair-to say?
"A.
I think it's fair to say that.- I was well convinced that we had a temperature problem, yes.
I don't think that I-was unique in that situation either.
"Q.
Temperature problem that could have been caused by.
the core being partially uncovered for example?
"A.
Yes."
(Porter, SIG Depn., 10/30/79, at 35-36, and 36-38) 9 0
O
+
e e
G 4
4 f
9 31-6
(
r Joseph' Logan Logan, the Unit 2' Superintendent who was assigned a freefloating. responsibility ir. the control room on March 28 l
by Gary Miller, dealing mainly with the operation ~of the emergency plans and procedures, testified that he did not
. initially recall seeing the actual high hot leg _ temperatures and has only a vague. recollection about the reporting of in-core thermocouple _ temperatures, though he recalls Porter saying that he did.not'believe the reported readings because "some were reading up and some reading down."
(Logan, SIG Depn., 9/12/79, at 5-6, 14)
Joseph'Chwastyk i
l Chwastyk, a Shift-Supervisor who arrived in'theLeontrol room during the morning, testified that' when he first came in he was told the method of core cooling was working and he did not have any reason to think that it was not, although~
he himself did not like it.
(Chwastyk, SIG Depn., 10/11/79, at 5-6)
Chwastyk testified that he was not sure he was specifically aware of either the DVM placed on the hot leg RTD leads,. cur of the strip chart on the back wall of the con-trol room showing the temperature between 700 and 800 degrees, but that higher than 700 degrees was "enough for me."
(Id.
at 9-12)
He interpreted those readings to mean that there was steam in the hot legs:
4 "Did you infer that that temperature meant that there was a lot of boiling in the core?
"A.
No._ Again, I was '.-
. I did not know what? happened, what transpired before I had gotten there...
I was told that the core, cooling through 80 gallons a minute through the core was sufficient to' keep the core cool.
I assumed.that-
, was correct."
(Id. at 13)
Pressed on whether he'now believed that continued super-heat: conditions in the hot legs were conclusive evidence of-steam' boiling in.the core, Chwastyk replied:
" A.
'No.
"Q.
Have you looked'.at-that?'
~
"A.
I haven't looked at it,-but IJdont'think^it does indicate that' simply-because it depends on the. water volume 6
32 a-h
. in the core and the pressure of the core.
There is no flow in there if the water volume was such that the water levels above, the core, you know, it wouldn't matter -- I couldn't tell from that temperature what the water volume was in the reactor coolant system."
(Id. at 15)
Finally, Chwastyk, like Porter, testified that there were various " rumors" about the extent of core damage when he came on, but that he personally did not get involved in assessing core damage; rather, he was more interested in getting the plant into a more stable mode of core cooling:
"[Q.]
I am kind of interested in the different folks' perception of how bad the accident was and when people began to think, you know, we really have something that is much worse than the ordinary, anything that we have ever had before.
"Do you feel that anybody was in that mode at the time you came in?
"A.
Yes, there were rumors, there were conjectures of total core damage to very little core damage.
That is one of the reasons I personally did not even want to get in-volved in how much core damage there was, or if in tact there was any.
I had enough to do to get the plant in what I would feel was a stable condition.
I really didn't have the time to sit down and determine or talk over what kind of core damage there was.
"Q.
But it is reasonable that the other folks in there at the time you came in really felt that something rather unusual and serious had happened?
"A.
I think the consensus was that there was core damage.
I think just the magnitude.was under discussion.
"Q.
But there seems to be an equally strong feeling that they had done something or other that stopped it from having.further damage?
"A.
I am not sure I understand.
"Q.
Did they also feel though that the. problem was over as far as continuing damage to the core?- I mean, I think they for example told you the core is-covered.
Was that a statement of faith?'
33
,e
1 R
i "A.
When I took the watch, I was under the impression
.that something had happened, but right now we were in a low --
and very inappropriate position.
At least the core was
- covered and we were providing cooling.tc it.
That's what I was told."
(Id. at 59-60) l Brian Mehler Asked in a deposition by.the Special Inquiry Group.what he inferred from the elevated hot leg temperatures, Brian Mehler, a Shift Supervisor who came into the control room about 6 a.m. on March 28 and closed the PORV block valve, testi-fled that he did not conclude from the steam in the hot legs that there was a " bubble in the core."
(Mehler, SIG Depn.,
'10/11/79, at 6-7)
"[Q.]
Did you infer anything specific from the hot leg i
temperatures?
"A.
No.
l "Q.
Did you consider how much superheat there might be in the hot legs givcn those temperatures?
"A.
No not at that time.
My main concern was to get the
~
pressure restored and get the pressure control back to the pressurizer."
(Id. at 7-8)
~
Mehler said he was not avare on March 28 of either the reported in-core thermocouple readings, or une precise readings coming off the hot leg RTDs, onAy that +Le hot legs were above 620 degrees.
(Id. at 11, 34)
ALked snether he inferred core damage from the radiation readings or the fact that the core dome monitor was pegged, Mehler testified:
"Well, we. realized we did have core damage at that time.
l We realized most of it came from the inventory out of the electromatic to the floor, how much core damage we didn't realize at that time.- It was hard to determine.
I think it would have been hard for any individual at that time to do that."
(Id. at 13)
"We figured we popped some pins..You wouldn't:have got them kind of radiation levels with'a crud burst."
(Id. at-23) s 34
John Flint Flint is not a TMI supervisor but a Babcock & Wilcox start-up engineer who was in the Unit 2 control room on March 28, reporting to Lee Rogers.
Flint recalled that by about an hour after he arrived, which was around 10:30 a.m.,
he believed that the core had previously been uncovered for some period of time (though he also testified that he did not realize it had been uncovered long.enough, or generated temperatures high enough,'to cause substantial generation of hydrogen).
(Flint, Pres. Comm..Depn., 6/30/79, at 23)
Flint has testified that he discussed this concern with Bill Zewe, Ed Frederick and' Lee Rogers, and that he thought Rogers was going to discuss it with Gary Miller and George Kunder.
How-ever, he does not know whether that occurred and did not discuss the matter further with Rogers.
(Id. at 23)
Flint does not recall discussing his conclusion with anyone else and doesn't believe anyone else in the control room had formed the same conclusion.
(Id. at 24)
Flint testified that he did' not believe the core was uncovered at that time, but had been uncovered at a previous time.
(Id. at 27)
(See Flint, IE 323, at 38-40 for same testimony.)
Rogers, as pointed out above, apparently never believed the core had been uncovered -- he testified that he did not believe that such a conclusion could be drawn from the high hot leg temperatures and, further, that no one had made such a suggestion.
d r
4 e
6 e
4 e
b 35 4
4
_w.
QUESTION 5, FIRST SET "5.
Is Instrument Man B correct in his recollection that the instrument technicians had told Mr. Ivan Portar of the results of their measurements of the in-core thermocouple voltages?"
This question is extensively discussed in our Report, Volume II, part III, at pages 132-134.
As the Report points out with supporting citations to applicable testimony, all of those involved in the taking of readings with a hand-held instrument off of the in-core thermocouple leads--instrumen't technicians Wright and Yeager, Foremen Weaver and Bennett, and lead instrumentation engineer Ivan Porter--agree that Porter was given an initial set of four or five readings, some quite high and some quite low', and that he returned to the control room to report these readings to Gary Miller, the Station Manager.
If this is what the question refers to, the' answer is yes.
As our Report goes on to discuss, after Porter returned to the control room the instrument technicians continued to take voltage readings from the in-core thermocouple leads.
These voltages were written down in a computer book next to-the numbers of the wires.
We are not aware of any testimony by " Instrument Man B" (Yeager) that Porter ever saw or was told about these additional readings.
However, technician Wright recalled in an IE interview that these readings were given to one of the foremen, Weaver or Bennett, and that they were " supposed to get" to Porter.
Wright went on to say that he was "sure" Porter saw them.
Wright's complete testimony is as follows:
"Q.
Okay.
After you take the second set of thermo-couple data, you go back upstairs to the control room.
Do you report this information to Ivan Porter or.
.?
"A.
Yeah.
He wanted us to take down what all the readings were with. all the point numbers and we had, again,
~
we just had like a scrap of paper with us that we marked this stuff down on.
And we took all the readings, you know, as in.1 through.20, I'm not sure how many points there are,
~
but we took them all down with the corresponding millivoltage readings next to them and we turned them in to Ivan.
I'm not sure if it was directly to Ivan or if we gave them to, say, Doug or Skip or whoever. - But, eventually we were sup-posed to get to Ivan, I'm not sure.
.I'm very sure he saw them, you know, but I don't know if he saw the converted figures as.far as what the. temperatures.were.
He, you know, we had them in millivolts then.
"Q.
Did you get any indication of what his impression was in, the second set.of readings?
36 m_
t "A.
I didn't talk.to him about the second set.
Let's-i see.
I know'that we said that we got it.
He said there's some there that are, that looked too high, that looked like we came, you know, that looked like they'd been damaged.
- Now, as far as anything more, I couldn't really recollect (Wright, IE 310, at 18-19.)
Shortly after these additional readings were taken and the group returned to the control room, as our Report points out, nonessential personnel were evacuated from Unit 2.
1 Ivan Porter has testified on a number of-occasions that he never in' fact looked at the additional readings that were written in the computer book.
Interrogated at some length on this question in a deposition taken by the Special Inquiry Group, Porter testified:
" Q.~
After you reported these approximately four readings to Gary Miller, did you go back downstairs to where the people were continuing to take readings?
"A.
I'm 90 percent.sure I didn't.
I don't recall going back down there, no.
In this case, I'm pretty sure I-didn't because I was convinced that I just wasn't going to get good data out of those thermocouples.
"Q.
What is it that gives you that ten percent uncertainty?
Is there something in particular that makes you think that you might have?
Either something that someone else--
"A.
No.
In my mind, I'm certain I didn't go back down.
That doesn't mean I didn't run back down there again, I guess. I'm certain I didn't.
"Q.
Have you had conversations with others or have you heard about others saying something that leads you to believe conceivable you did go back down there?
'A.
No.
~
"Q.
Your own recollection is that you didn't?'
"A.
As I say, I'm fairly certain I did not go back down there.-
"Q.
Did you know that they were going to continue to take : readings over some period of time at the time' that -you left and went up to' talk to Mr. Miller?
"A.
I think I knew that they were probably going to go-ahead,and(take millivolt readings, but-I don't know that I 37
instructed them to take them.
As best as I can recall,.
the conversation was, is it necessary to unhook each one and hook it up.
And I just told them, no, it wasn't I don't think I particularly cared if~they took them or not.
I may have asked them to go ahead and finish taking them, but as I say, at that point in time, when I saw that there was such a disparity in the readings, I didn't think I was going to get that~ valuable of information from them anyway.
"Q.
Did any of the people that you left.down there or anyone else report to you later on March 28 that they had taken a complete set of readings or a large number of read-ings?
"A.
I didn't recall them saying that.
The fellows--
in conversations since then with Skip Bennett, they left when they evacuated nonessential personnel.
I would have expected that Skip would have told me, but I don't specifically
--I would expect that he would say, Well, you know, the read-ings are in the computer book or whatever and gone on.
I don't recall him saying that.
He may have.
If he said he told me he did, he probably did.
"Q.
In your conversation with him about this, has he told you that he thinks he probably did or that he does're-call this?
"A.
I didn't even ask him.
"Q.
Do you remember actually seeing any' additional readings other than the first four, approximately-four read-ings during that day?
In the~ book or on a piece of paper or anywhe.re else?
"A.
Not on-the 28th.
I'believe we did put the'DVM
-on a couple more before I went back upstairs, down there, but don't recall the millivolts or even converting them or anything.
~"Q So you think that in addition to the.four that ycu saw on the' meter _ readout, you may.have had a couple more millivolt readings in total,- before you'went up to. talk to Gary Miller?' Am I understanding. you.correstly?
"A.
Yes.
"Q.
'But after1you went.back upstairs, do you recall seeing any additional large number of: readings - or! hearing of sthem7from~ anyone on that; day, the 28th?
1 381
-w.
s a
a l,___.
"A.
No.
I'm convinced there were no more readings that day other than what anybody might' have taken.from the computer.
I believe by the afternoon, NRC people were taking data out of the computer.
"Q.
When you say there were no mors readings, you now know that the technicians did take millivolt readings ands wrote them in a book?
"A.
Oh, I know they took them after I came back up, but say after 10:00 o'cloc'k when they left the unit, I don't think there were anymore taken.
"Q.
My question is whether you became aware or to your
. knowledge anyone else became aware, other than the people who took the readings, of the numbers in that computer book on March 28th.
"A.
No.
I don't know of anybody else becoming aware of it.
"Q.
You did not become aware of them?
You didn't open the book and see what the readings were?
"A.
I didn't look at them.
I'm sure now that had I looked at the readings laid out the way they were, they would have meant something different to me,'because it's obvious that they start high and go low even with the disparity in the readings when you can see the organization in the readings, when you look at them.
I'm not saying that Skip didn't say, the readings are-in the book, we're leaving.
But I did not open the book and review the readings.
"Q:
Do you remember any conversation with' Skip cx: with anyone else to the effect that, Yes, we took some more. read-ings and they are-the same pattern as the first five, or anything like that?
"A.
I'm sorry.
I just don't.
(Porter, SIG Depn.,
10/30/79, at 13-17.).
'In anl earlier IE interview, Porter had testified:
"I don't recall seeing 7 millible (sic) readings again, at that time. LIn fact, it was'sometime later, I was'even aware that they existed.
I' guess I. forgot they took them,
.quite frankly.
I'm sure they must have. told me.
Well, they do! confirm it, though.
They're still scattered anywheres from 200. degrees to 2,500 which is about what'I saw on the digital readout.
There:are~just more of them."
- (Po rte r,.
- IE 324, at 12.)
.39
Gary Miller has also testified that he does not recall learning of any additional readings on the 28th:
"O.
You remember that he reported back to you a number of readings but you only remember him having done that once.
"A.
That is true.
I' only remember. a very limited number of readings and I only remember once.
That is reinforced in my own mind by the fact I never really discovered the number of readings taken until like I said I believe Mr. Bennett came back from vacation, at which time the computer sheets were found.
I didn't know many people knew they existed before that.
That was two weeks after the accident or so,' I believe.
"O.
Are you saying that at no time during March 28 did
.you realize that somebody was down there generating additional readings other than the ones Mr. Porter reported to yoil?
"A.
That's right, and what I am saying is I think that is even reinforced by the fact that I don't believe those computer sheets were available to anybody until Bennett came up with them.
I don't believe that was until a couple of weeks after the accident.
A week or two.
I subsequently at
- least had been shown testimony where there were separate sets of readings taken with separate instruments on more than five of these.
I had no idea there were 52 readings or whatever number there were that I can remember."
(Miller, SIG Depn.,
10/29/79, at 5.)
Foremen Weaver has testified that he was not directly involved in the taking of additional readings.
(Weaver,_
IE 266, at 19.)
Foreman Skip Bennett testified that he was the one to record the additional voltage readings in the com-puter book, and that when they were through taking the read-ings they all returned to the control room and Bennett placed the book on the computer console, after informing Porter that there were "several thermocoupl.es that were extremely hot in the neighborhood of 2,000 degrees Fahrenheit and then I believe that was about it."
Bennett's c 7mplete testimony is as follows:
"Q.-
How did you record _the data that you were taking off?
"A.
I used a computer point identification book, as we were' using that to check rows. terminal numbers.
I was writing them in next_ to the computer point in the book.
"Q.
Do you recall that any' set.of measurements were copies down on say'a~ scrap piece of paper?
"A.
Not to my knowledge, no.
40
"Q.
Do you recall any thermocouple readings up to j
the range of 75 millivolts?
"A.
No, I don't recall really what any of the readings were other than the first one because it.was extremely higher than what I-had expected to see.
"Q.
After the second. set of measurements was taken, do you recall any discussion, any further discussion of the core being uncovered?
"A.
Yeah, I believe that came up as a topic of discus-4 sion and we, I can't remember who said that, there
-was no formal statements made down there at that time, just the technicians, and myself and Mr. Gilbert talking.
It seemed.
I was under the impression that the core had possibly been uncovered.
"Q.
Did you make a statement to Ivan Porter to that effect?
"A.
Yes, I believe we did when he was down there and we had pretty much taken to believe the first reading we got up around 2,000 degrees.
"Q.
What was his response?
"A.
I don't really remember what his verbal response was.
I have a feeling that he was more or less in agreement with everybody else that was down there.- We had possibly uncovered the core was the only way we could see that you could have obtained temperatures of that magnitude.
"Q.
So'after you complete the measurements in the range of 8:45,, 8:50 what happens then?
'r.
Yeager and Mr. Wright "A.
Myself, Mr. Gilbert, M
proceeded up to the Control Room.
I believe Mr. Wright and Mr. Yeager then returned to the Unit 2 instrument shop.
I had placed the computer.
the point identification book back on the computer console.
I had informed Mr. Porter that there was several thermocouples that were extremely hot in the neighborhood of 2,000' degrees Rahrenheit and then I
~
believe that was about'it I think I took^the time at that time I looked at the post trip re.
. not the post trip revie".
the sequence of events that had typed out of the computer that morning and then myself and Mr. Gilbert returned to the Unit 2 instrument shop.
(Bennett, IE 311, at 17-19.)
i a
41 l
b'-
Instrument technician Yeager testified that after the readings were taken the group reported to the Shif t Super-visor's office, and that after a few minutes they all
- evacuated; during this time, according to Yeager, he was with Wright the entire time.
(Yeager, IE 315, at 18-20.)
In sum, Bennett says that he wrote the additional read-ings in the computer book and that he took the book and returned it to the computer console.
He also says that he told Porter they had taken the readings and that there were a few that were in the vicinity of 2,500 degrees.
Wright says that the readings were "given to" either Bennett or Porter, and that while he does not recall discussing them with Porter, he is "sure" Porter saw them.
He also recalls a comment made to Porter upon return to the control room about a few of the
' readings being "too high.
that looked like they'd been damaged."
Porter says that he must have been told that the additional readings had been taken, but that he does not recall it, and that he is sure he did.not look at them.
Miller says he did not learn until much later that the additional readings had been taken, and Porter says that he forgot about it until some time much later.
All of the above stestimony appears to be consistent with Bennett having returned to the control room with his techni-cians, placed the book on the computer console, and in the presence of Wright having said to Porter that they had taken some additional voltage readings and that a few of the thermo-couples were reading around 2,500 degrees (a fact already known to Porter).
A further comment may have been made about these readings being due to " damage. "
9 42
QUESTIONS 6, 8 and 9, FIRST SET; and OUESTIONS 5 and 6,
' SET TWO "6.
Are Messrs. Chwastyk, Ross and Frederick correct in their recollections that in the afternoon of March 28 Mr. Miller was aware of the pulse on the pressure recorder and/or actuation of safeguards systems that occurred at approxi-mately 1:50 p.m.?"
"8.
Which of the TMI supervisors who were present believed on March 28 that the pressure-recorder had indicated a real rise in containment pressure at 1:50 p.m. and which of the supervisors believed the recording to have been the result of spurious electric signals?
"9.
Which of the TMI supervisors present on March 28 were aware on that day of the following:
-- actuation of containment sprays;
-- negative pressure pulses on instruments that used containment pressure as a reference;
-- a rise in containment temperature recorded by one or more containment tempera-ture sensors?
"5.
Which of the TMI supervisors or reactor operators recall informing or discussing with Mr. Gary Miller during the afternoon or evening of March 28 that the containment sprays had automatically initiated at approximately 1:50 p.m. and were turned off shortly thereafter?
If Mr. Miller was not informed what reasons have the supervisors given for not having informed him?
Where in the control room or adjacent offices was Mr. Miller located from approximately 1:50 p.m.
to 2:00 p.m. on March 28?
"6.
Does Mr. Mehler recall-having discussed-with any of the other TMI supervisors or.
reactor operators (as' he recalled discussing with an NRCfinspector) his' reasons for believing that the pressure pulse record.at-1:50 p.m.
on March 28Lreflected a real pressure increase I
43 6
e
in the containment building?
Were the TMI supervisors who dismissed the pressure pulse
~
and actuation of containment sprays as having resulted from spurious electrical signals aware of the circuit logic (as were Messrs.
Chwastyk and Mehler) requiring at least two of three pressure sensing circuits to detect electrical signals equivalent to a pressure of at least 28 pounds per square inch in order for the containment sprays to be triggered?
What was the rise time of the pressure pulse on the recorder?
What was-the decay time?
Did this pressure pulse have the characteristics of.a spurious electrical signal?"
All of these questions basically ask the same thing:
which of the supervisors in the Unit 2 control room were aware on March 28 of the pressure spike and/or containment spray actuation, which believed that the spike reflected an actual increase in building pressure, did they discuss the matter, and what is the testimony concerning Gary Miller's knowledge that the spike occurred.
In addition, question 9, set one, asks whether any supervisors were aware of changes in reactor coolant system pressure or containment building temperature; question 5, set two asks where Mr. Miller was located at 1:50 p.m.; and question 6, set two, asks about the characteristics of the pulse itself, and whether super-visors were aware of the coincident logic circuitry.
The question of which supervisors knew on March 28 about the pressure spike and/or spray actuation, whether there was any recognition of a possible hydrogen explosion, and what was known by Gary Miller is exhaustively covered in Volume II of the SIG Report, Part III, pp. 138-159, with citati6ns to relevant testimony.
A complete answer to the question would necessarily include a complete recapitulation of that section of the Report.
This memorandum will. simply summarize-the discussion in the Report in order to' answer directly the questions posed by Congressman Udall.
.According=to sworn testimony, both Shift Supervisor William Zewe and control room operator Ed Frederick saw the. spike in~ reactor building pres'sure as it occurred.
They were also aware of the building spray system actuating.
(Zewe et al.,-SIG Depn.,-9/11/79, at 256-264).
Zewe recalls discussing the spike with Operations Supervisor Mike Ross Land Shift Supervisor J a Chwastyk, and they agree that'they 44 I
were also aware both of the spike and of the spray system coking on.
(Id.; Ross, SIG Depn., 9/18/79, at 42-44; Ross SIG Depn., 10730/79, at 42-44; Chwastyk, SIG Depn., 10/30/79, passim).
Shift Supervisor Brian Mehler.was also_ aware of both the spike and the actuation'of the spray system.
(Mehler, SIG Depn., 10/30/79, passim) Engineer Walter ("Bubba")
Marshall was also aware of both occurrences. (Marshall, SIG Interview, 2/22/79).
Each of these individua'ls with the exception of Chwastyk and Mehler has stated or testified that there was general discussion about what had occurred and that the pressure
' spike was attributed to a spurious electrical signal or F
failure.
(Same references as above.)
George Kunder, Superintendent-Technical Support for Unit 2, who accompanied Miller and Jack Herbein, Met Ed's Vice President, to Harrisburg shortly after the spike occurred and Joe Logan, Unit 2 Superintendent, have both testified that they were not aware either of the spike or of the actuation' of the building spray system, nor were they aware of any,
unusual sound at the time.
(Kunder, SIG Depn., at 75-76; Logan, IE Interview, 5/9/79, at 31-32).
Lee Rogers, the B&W Site Representative, has testified 4
that he was not aware of the pressure indication or the actuation of the spray system but that he did hear a noise at the time, and that he either heard conversation or was told that the noise was probably due'to the ventilation dampers in the control room ventilation system slamming shut.
(Rogers, SIG Depn., at 47)
Rogers' assistant John Flint has said that he was aware of the pressure spike and the actuation of the spray system, and that he heard a noise, j
but that he too attributed the noise to the cycling of_the ventilation dampers.
(Flint, IE 275, at 6-7)
As pointed out in the Special Inquiry Group Report, Gary Mi'ller has consistently testified that he was not-aware of the pressure spike on' March 28 and that he:was not aware of the actuation of the spray pumps at the time the system came on.-
(Miller, Statement, 4/76, at 24; Miller, IE Interview, 5/7/79, at 70;. Miller, Pres. Comm.
Testimony, 5/31/79, Tr. at 57; Miller, SIG'Depn.,~10/29/79, at 19-22).
According to Miller, he was first told of the spike by Bill Lowe, a-GPU consultant, on Friday morning, March 30, and at.that: time' asked Ivan Porter to investigate more' thoroughly.what'might have caused it.. Miller does 3
45
~
7 f
v w e
't
recall, just before leaving for Harrisburg, hearing.a
" thump ".
He remembers that he was standing next to Mike Ross and Bubba Marshall at the time and that he asked "what was that?"
According to Miller, someone said that it was probably the ventilation dampers.
(Miller, SIG Depn.,
9/20/79, at 31-3,2; See also Miller, IE 159-160 at 70-71)
Miller testified in the deposition that it was not until
" subsequently" that he learned that the spray system had CCme on.
As also pointed out in our Report, a number of others have stated or testified on one or more occasions that Miller.was aware of the pressure spike on Wednesday.
(See Report, pp. 143-146 of Volume II, part III)
Ross initially testified that he believed Miller was among the group in the Shift Supervisor's office when the spike was reported.
(Ross, SIG Depn., 9/18/79, at 42).
Pressed on this question in a later deposition, Ross said that his recollection on the subject of discussing the matter with Miller was a "little vague," but that he recalled some discussion about a noise and his telling Miller, "it's not time to get nervous now.
We're going to have to go from where we are."
(Ross, SIG Depn., 10/30/79, at 10).
Ross said he did not recall if
~ Miller actually looked at the pressure spike.
Both Joe Chwastyk and Brian Mehler also testified that they believed Miller was aware of the pressure spike.
Chwastyk, who said in a transcribed interview by the Special Inquiry Group on October 11, 1979, that he recalled having related to Miller his conclusions about-the pressure. spike (at 18), also said later in the interview that he "really didn't remember" whether he did tell Miller about the spike itself.
(At 21).
In a subsequent deposition on October 30, 1979, Chwastyk at first testified that his "best recollection" was that he had told Miller about the spike and about his conclusion that there had been some sort of explosion, but again admitted later in the deposition that he could not be certain.
(Chwastyk, SIG Depn., 10/30/79, at 17 and 19-20).
Mehler, who recalls discussing the spike with Chwastyk and Ross, testified that he recalled info. ming the people in the Shift Supervisor's office (where Roso first heard about the spike) that they had had a pressure spike and building spray actuation,.and that he believed that both Miller and Ross were in the office at the time.
(Mehler, SIG Depn.
10/30/79, at 17-18).
Control Room Operator Ed Frederick, who argued _at some length in a deposition with Qwacial Iaquiry Group st'aff-
"A.
members'that it would not have been reasonable at the time to' infer that an explosion had taken place and that the interpretation of an electrical malfunction was more sensible in light of the information known at the time, was not asked specifically in that deposition whether he knew whether Miller was aware of the spike.
(Zewe, et al, SIG Depn.,
9/11/79, at 256-264).
Frederick had been asked in a hearing before Congressman Udall's Subcommittee on May 11 whether there was a " reaction from other people in the room" when the
~
spike occurred, and during the discussion that followed said
- that, "I think Mr. Marshall tried to figure it out, and Gary Miller was particularly interested in it."
(Hearings, Part I, Tr. at 145).
In the same testimony, Frederick also said that he concluded that the spike was due to an instru-ment malfunction,'and that because there was no other way to understand it, no further attention was paid to it.
(Id. at 143-148).
In this connection, Bill Zewe, the Shift Supervisor at the time, testified that he did not discuss the spike with Miller (Zewe, SIG Depn., 9/20/79, at 257-258).
Earlier in the same deposition Zewe had testified that he was the-liaison between his control room operators, Frederick and
~
Craig Faust, on the one hand, and Miller's. management group on the other, so that if he didn't know something reported to that' group, his operators would not know it either.
(Id. at 99-103).
Miller has also testified that he attempted only to speak with his management group that day, rather than directly with control room operators and others in the control room.
Question 6, Set One asks who is " correct" about whether Miller was informed of the pressure spike on March 28.
Both Mehler and Ross have testified that supervisors in the shift Supervisor's office were informed of the spike (which is how Ross learned), and that it is their best recollection that Miller was one of those present when that occurred.
(Miller was at that time preparing to leave for Harrisburg, with George Kunder.)
Ross has said.he is " vague" about any con-versation with Miller about the spike, and does not know if Miller looked at it.
Ross did recall Miller hearing a noise -- which would corroborate Miller's similar account..
Chwastyk has testified that it is his best recollection tnat he related to Miller on the 28th Chwastyk's conclusion about a possible explosion, but that he cannot be sure.
Problems
~
with-this testimony include Mehler's confusion about whether an order to secure electrical' equipment in the containment came on the 28th of'29th (discussed in our-Report, which 6
14 7 t
4 1-_c
, concludes that that order was given on the 29th); Chwastyk's testimony that his discussion with Miller concerned attempts to redraw a bubble in the pressurizer -- an evolution of which
, both Miller and Ross (Chwastyk's direct supervisor) have testified they were unaware; and the timing of Chwastyk-Mehler conversations which most likely occurred after Miller-left the site (all as discussed in our Report).
Ed Frederick also testified on'one occasion that Miller was " interested in" the spike at the time.
Miller has consistently maintained that while he heard a noise, he did not learn ofLthe' spike til Friday morning.
His testimony is circumstantially' corroborated by the testi-mony of Ivan; Porter and Bill Lowe about their conversations with Miller on Friday.
Also, George Kunder, who was supposed to be in the control room gathering plant data for Miller at the time, says he did not become aware of the spike, and that there was no discussion of it among Miller, himself and Jack Herbein on the ride to Harrisburg.
Others in the control room, including Logan, Rogers, and at least two NRC inspectors, have also said they were unaware of the spike, lending credence to the possibility that one could have been present but unaware
- of the indicated pressure increase.
Miller has also said that he resisted going to Harrisburg and that if he had believed there were problems with the plant making it inadvisable for him to leave, he would not have done so.
In sum, the testimony is quite divided and makes it im-possible to conclude with anyl certainty what in fact happened.
Based on the weight of the testimony, however, it appears more probable that Miller was told about, or at least had reason to be aware of the increase in building pressure.
From this testimony, however, it is impossible to determine whether Miller probably learned of an increase lto 4 psig or to 28 psig.
Of the testimony relating to Miller's contemporaneous knowledge of the, spike,'only that of Chwastyk suggests that Miller, even if he knew of the spike or an increase-in-building pressure, may have been told that it.might be a real signal; Ross,'Zewe and others_have said that the spike was' generally attributed to an electrical malfunction.
(See, e.g., Ross IE 226 at 4-5:
"I associated _it with an instrument-problem per-haps and I think so did Miller at the time because we just went-on to something:else.")
Based on-the. weight of the-evidence,
-it appears more probable that if Mi'ller learned of the reactor
~
building pressure increase, it was in~the. context of an.indi-l cation that was not understood or was" discounted as an electri -
cal-malfunction, rather'than as'a possible-hydrogen explosion.
If Miller waszin fact informed of the pressure increase or_was 6
48
~
~
)
aware of it at 1:50 p.m. on March 28, it is impossible to dete'rmine from available testimony whether it is most likely
'that-he subsequently forgot the event, or if he simply failed to take account of what was happening, or if he has testirlec falsely'about not recalling learning of it at the time.
Question 8, Set One, asks which supervisors believed 1
that the pressure recorder indicated a real rise in building pressure.
Only.Chwastyk and Mehler have been identified by i
any testimony as having reached such a conclusion:
Mehler that some sort of chemicel reaction might have occurred,-and
?
Chwastyk that a possible hydrogen explosion might have caused the pressure increase.
(Their testimony is discussed in great-j detail in our Report.)
j Question 9, Set One, asks'whether any supervisors were-aware of increases in containment building temperature or changes in other parameters used as references for reactor building pressure.
Subsequent review of data has shown a concurrent-increase in reactor building temperature, and a very small -
dip in the recording of reactor coolant system pressure which i
device uses reactor containment building pressure as a reference y
level.
Ivan Porter testified in a deposition conducted by the Special Inquiry-Group that when asked by Miller to' review the matter on Friday, he took out the reactor coolant system-wide-range chart and noted a "down blip on the chart at ap-proximately the right time, which is about as best you can-do with the charts and speeds involved."
(Porter SIG Depn.,
10/30/79, at 29)
There is no evidence that Porter did this on Wednesday.
We are unaware of any statements or testimony taken by any investigation suggesting that anyone in the control room.
on the 28th was contemporaneous 1y' aware of changes in reactor building temperature or other parameters which used reactor
^
building (atmospheric) pressure as a reference.
Question 6, Set Two, asks whether Mehler discussed with others his reasoning that the pressure recorder had indicated an actual pressure spike in the containment building.. This subject is covered in detail in our Report, Vol. II, part III, pp. 141-149.
In depositions. conducted by the Special-Inquiry Group,.Mehler recalled discussing his conclusion with an NRC inspector (who we were'not able to identify) and with' Joe'Chwastyk (Mehler, SIG Depn., 10/30/79, at 5-15).
Mehler recalls ex-
. plaining the' coincident logic circuitry to.the'NRC inspector.
He did not specifically. testify;that he and Chwastyk discussed-
~
the circuitry, but.they did reach a conclusion, according to Mehler,;that the spike was?real and might have been caused.by an explosion.
In his1 deposition, Mehler does not specifically, recall discussing the' logic circuitry with Miller;-he'says that O
49 t
I
's,
h
' the Shift Supervisor's office was " informed" of the pressure spike and that he believed Miller was there at the time.
(See above)
Mehler did not recall discussing his conclusion with any other Met Ed supervisors.
(Mehler, SIG Depn., 10/30/78, at 15-18, 22-23)
The same question asks whether those who dismissed the pressure spike as an electrical impulse were aware of the coincident logic circuitry for the spray system (actually, there is a coincident logic circuitry for both building isolation and spray actuation).
Shift Supervisor Bill Zewe and his. crew of operators have testified before Congressman Udall's Subcommittee (Hearings, P' art I, at 147) and in a deposition conducted by the Special Inquiry Group (Zewe, et al.,
SIG Depn., 9/20/79, at 256-264) that they were aware, at least after the fact, of this circuitry.
The'same question asks several questions about the charac-teristics of the pressure spike.
On the strip chart itself, the spike appears as a virtually instantaneous rise and fall, however, due to the slow speed of the chart this tracing would not assist in determining how many seconds the pulse lasted.
Similarly, Zewe and Frederick have testified that the pen re-corder went straight up and straight down.
(Id.)
Again, how-ever, some lag time would normally exist between the actual pressure increase and the movement of the pen, giving the pulse a more instantaneous appearance even to one watching the pen recorder at the time than was accurate.
The best estimates can probably be derived from subse-quent examination of the alarm printer, which shows the times (in seconds) from the time the pressure rose from 4 psig (con-tainment isolation alarm) to about 28 psig (spray actuation alarm), then back through 28 psig (spray alarm cleared), to 4 psig (isolation alarm cleared).
The printer indicates that building pressure went from 4 psig to 28 psig in six seconds, a' gain registered 28 psig 5 seconds later, and decreased to 4 psig about 15 seconds after that.
Based on this printout, the pulse may'have lasted about a: total of 25 seconds.
The alarm printer.was not available at the time because of a printout backlog.
The same question. asks whether the pulse has "the charac-teristics of a spurious electrical signal."
It is unclear what th'e " characteristics" of a " spurious" signal would be.
~
If the: question is intended to suggest that a spurious elec-trical signal would probably be. instantaneous rather than 50 4
L.
' sustained then the shape of the pulse as we can now infer it from the alarm printer was less characteristic of such a signal than the pulse as it appeared to those watching the pen recorder or subsequently examining the spike on the graph.
However, as pointed out above, the alarm printer in-formation was not available at the time of the pulse.
In this connection, a number of other electrical instru-ments in the control room malfunctioned at.approximately the same time as the pressure spike due to what was determined to have been the loss of power in-two' electrical busses.
At-least two individuals in the control room at the time, both.
of whom discounted the spike as an electrical failure, were also aware of these contemporaneous electrical problems in other instrumelits.
(Flint, IE 323, at 19; McGovern, IE 224 at 28-29)
With respect to Miller's precise physical location from 1:50 p.m. to 2:00 p.m. on March 28, as pointed out above, Brian Mehler believed Miller was in or near the Shift Super-visor's office; Mike Ross testified that he believed he was standing next to Miller; and Miller has testified that he believed he was standing next to Ross and Walter ("Bubba")
Marshall at the time he heard a noise.
(Miller, SIG Depn.,
9/20/79, at 21; see also Miller, SIG Depn., 10/29/79, at 21-22) t 0
1 9
e e
e s
9 d
~51
QUESTION 7, FIRST SET: and QUESTIONS 7 AND 8, SECOND SET "7.
Is Mr. Illjes correct in his recollection tha'.
on March 28 he was told about the pressure pulse, and that the possibility of a hydrogen explosion was discussed in the evening?
"7.
What were the circumstances leading to review of the reactor building pressure on Thursday, March 29?
Which officials of Metropolitan Edison and General Public Utilities were involved in this review?
Who ordered the review?
Was the pressure data reviewed as part of a general effort to review all data, or was the review undertaken as the result of TMI personnel remembering that the pressure pulse had occurred?
If the latter, which TMI personnel recalled the pressure pulse?
At what time and to whom was the pressure pulse information given to NRC staff?
"8.
At what time did TMI supervisors recognize that there were non-condensable gases i.n the system?
Did the pressure and temperature data available at any.
time on March 28 clearly indicate the presence of non-condensable gases?
If so, and this was not recognized on March 28, what were the reasons for the failure?
Beginning with the last question, Volume II of our Report, part III, at p.
49, discussing the operational response to the accident, points out that on Thursday evening, March 29, control room personnel first began to suspect that there was a substantial amount of noncondensible gas in the primary reactor coolant system.
(See, - e.g., Floyd, SIG Depn.,
9/13/79, at 125-126; Moore, IE'306, at 12-13; Chwastyk, SIG Depn., 10/11/79, at 29-31; Nitti, SIG Depn., 10/11/79, at 4-5.)
Our Report also points out that according to both testimony and control-room logs, operators and supervisors ~
became aware in the afternoon or early evening of March 29 that gas was accumulating in the make-up tank and that periodic venting of that tank caused leaks into the auxiliary.,
building resulting in observable releases to the atmosphere up the vent stack.
(Report, Volume II, part III,'pp. 49-53)
Also, as our Report discusses in detail, NRC personnel became aware of this~ problem Thursday night.and sought:
assistance from B&W engineers in calculating hydrogen genera-tion rates.
(Id. at 212-213) 52 Y
The-question also asks whether'" pressure and temperature" data available-the day before, March 28, clearly indicated the presence of noncondensible gas ful the system.
The data that indicated the presence of noncondensible gas cn1 Thursday,-March 29, was not pressure and temperature data but rather the correlation between pressure data and pressurizer level data.
Chwastyk, in his deposition, cited above, pointed out that the characteristics of noncondensibles in the system could be determined by observing system pressure, pressurizer level and the time of pressurizer spraying.
See also Floyd's testimony cited above.
Similarly, Don Nitti, a B&W engineer' who was asked on the night of March 29 to undertake calcula-tions to determine the size of any' bubble of hydrogen or other noncondensible gas, used a number of different sets of read-ings for system pressure and pressurizer level to make his calculations.
(Nitti, SIG Depn., 10/11/79, at 4-5)
The approximate size of an hypothecated bubble of noncondensible gas in the primary system could be calculated ~ knowing, for several points in time, system pressure and pressurizer level, and also knowing the amount of coolant added or sub-tracted from the system (by make-up flow or letdown) in the intervening periods.
Such a calculation ~could, however, only-be reliably performed with stable bubble control in the pressurizer -- a condition not attained until Wednesday' evening.
The meaning of the question whether temperature-pressure relationships would lead to a conclusion about noncondensibles is unclear.
presumably, sophisticated heat transfer analyses could lead to such a conclusion, but there is no evidence that such analyses were done on March 28 or that the data necessary to do them was available.
The fact that an attempt which was made from approximately 9 a.m. to 11:30 a.m.
on the morning of March 28 to collapse what were. presumed to be steam voids in the hot legs failed to achieve that result may be Cue, in retrospect, in part to the presence of non-condensible hydrogen gas,--but may be due as well to the temperature of the. core,-flow patterns in the system and the amount of high pressure injection flow.
Since, at that time, any steam in the hot legs that was over 642 degrees would not itself have-been condensed by the maximum pressure being attained, 2100 psi, the fact that_the-pressurization
' attempt failed would not in itself lead to'a conclusion that non-condensible gasses were.present in the system.
(This matter is, discussed.at greater length in.our Report, Volume II, part 111, pp. 31-33.)
Questien 7, Set'Two, asks.the precise. circumstances in which the reacter building pressure spike was discovered on Thursday evening, by whom, and.why..Our Report-stated (and it.did not appear to have'been in dispute) that the spike 53 9
9
was identified by GPU engineers late Thursday night or early Friday morning, causing further analyses of a possible hydrogen bubble to be undertaken by GPU personnel and by B&W personnel in the early morning hours of Friday, March 30.
(See Report, Volume II, part III, at 49, 138-139, and 117, with citations'to sources therein)
However, since we did not determine precisely who found the spike on Thursday night, additional interviews were conducted to answer this question (as well as to provide additional information relating to Question 1, First Set).
These interviews, when taken together with deposition and other evidence previously-available, make clear exactly how the spike came to be identified and by whom, and what h'appened thereafter.
According to Met E'd engineer Richard Bensel, who reported to work about 7 p.m. on Thursday night to relieve Ivan Porter, Porter and others had begun to pull together and photocopy strip charts of various plant parameters for the relevant period during the accident in order to begin an analysis of what had happened.
Bensel undertook to begin to review these charts to familiarize himself with them.
Upon reviewing the reactor building pressure chart, Bensel found the 28 psig pressure spike.
(Bensel, SIG Interview Memorandum, 2/22/80)
Bensel recalls showing the spike to a number of other.
individuals in the control room area concerned with operations, including Ron Toole, GPU start-up engineer.
Toole said that the spike had been caused by a stray electrical signal when an inverter momentarily lost power.
However, Bensel talked with control room operator Hugh McGovern and others and-found that the spray system had come on at the same time.
Looking at the alarm printer, he also discovered that all six pressure switches had activated.
This led Bensel to conclude'that there had actually been an increase in reactor building pressure.
(Id.)
~
Aware that control room operators were concerned about~
the possibility of noncondensible gas in the primary system, Bensel went to GPU consultant Bill Lowe and told him that it looked as though they had had a hydrogen burn.
(Id.;
Lowe, SIG Interview Memorandum, 12/4/79)
Lowe then
' discussed the spike with several others, including Tom Cr.immins, Chief Engineer for Jersey Central Power and Light; Joe Logan; and' Jim Moore, a GPU engineer.
(Lowe, SIG Interview Memorandum)
Moore recalls receiving a request from Lowe about ll'p.m. on-the 29th tk come to the control room and assist in analyzing whether there~was hydrogen in the primary system and, if so, hcw much.
Moore completed 54 e
his first set of calculations about 3 a.m.
on the 30th.
(Moore, IE 306, at 4-5, 12-13)
Bubba Marshall, a Met Ed engineer, recalls that at some time after 10 p.m. on Thursday evening Bensel was looking at the reactor building pressure strip chart and pointed out the spike to him and to Jim Floyd, Unit 2 operations
~
supervisor.
Bensel expressed the view that the spike was not spurious but was an actual pressure increase.
Marshall recalls that Bensel and Floyd then went into the Shift Supervisor's office to talk with Jim Lowe about the spike.
(Marshall, SIG Interview Memorandum, 2/22/80)
Lowe also recalls a call being placed to B&W'to Bill Taylor and Don Nitti for assistance.
(Lowe, SIG Interview Memorandum)
Don Nitti, a B&W engineer, has testified that Thursday night as he was about to leave work his boss, Jim Taylor, asked him to stay and do some work on hydrogen generation.
This was apparently based on an NRC request.
Nitti was told that it was not clear whether there was a hydrogen bubble or, if so, what was its size.
Nitti wrapped
' up his work about midnight and went home after a phone call to the NRC.
About 3 a.m.,
he was called to come back to the office to do further work, based on additional information and confirmation of a probable hydrogen bubble.
(Nitti, SIG Depn., 10/11/79, at 4-5)
This would have corresponded to the time when the spike was positively identified and Moore had finished his first calculations at Three Mile Island.
The first written record of the pressure spike notifica-tion having reached NRC headquarters via a PN notice is about midday on March 30.
However, NRC officials, including engineers from NRR, were present on-site and in the control room on Thursday night performing analyses of data together with GPU engineers.
Lowe recalls that an NRC inspector on an open line to NRC in the Unit '2 control room came over to him at the time Bensel first brought in the pressure spike, and that the NRC man helped Lowe and Moore with their initial calculations between midnight and 3 a.m. on' March 30.
(Lowe, SIG Interview Memorandum)
The IE Investiga-tion Report, NUREG 0600, determined that based upon " inter-views and log books," the NRC was informed of the. pressure spike early.in the morning of March 30.
(' UREG 0600, N
- p. I-4-49)
The hydrogen burn appears to have become general knowledge among both company and NRC officials ~at 1
Three Mile. Island as they arrived for work dn Friday morning.
as our Report points out, concern about the hydrogen bubble and.the knowledge of the presure spike were both central to 55
the deliberations of NRC staff officials on Friday in Bethesda concerning evacuation.
(Report, Volume III, part
-III, pp. 223-224)
Theodore Illjes, a control room operator who came on duty in the Unit 2 control room about 6 p.m. on March 28, stated in an IE interview and in a subsequent interview with
~
the Special Inquiry Group that he was initially briefed by another control room operator about the fact that at about 2 p.m. there had been an ESFAS (actuation of emergency features) from an increase :bi reactor building pressure, and a recovery from the condition shortly thereafter (Illjes, IE 261, at 6, 8; Illjes, SIG Interview Memorandum, 2/22/80)
Question 7, Set One, asks whether he is " correct" :bi his recollection that he was told about the pressure spike when he came on duty.
There appears to be no' reason to doubt that he was.
Illjes further told the IE interviewers that later in the evening there was discussion between him and "one of the engineers" about what had caused the spike and about a possible hydrogen explosion; that a B&W representative or NRC inspector had asked for information about the spike; that the strip chart was taken out and xeroxed; and that he recalled that that same night, it had been determined that there was a bubble of noncondensible gas in the system.
The full testimony is as follows:
I "Q.
Do you recall being briefed on the wide range-narrow range reactor building indications?
"A.
I was told that they had a spike on both indications of the reactor building pressure recorder.
There was some discussions as to what it was.
A hydrogen explosion was discussed.
This was later on in the evening.
"Q.
How late in the evening.?
"A.
Oh my.
"Q.
You took the controls at 6?
"A.
At 6.
Well....
"Q.
.6':20 or so?
"A.
No, I would say it was more...
It was-later,cause' we were...
It was after we drew a bubble.
O.K.
If I want to 56
relate it, I would say it.was after we drew the bubble in the pressurizer which we did after that.
As far as what time
-that was mentiered, as far as we discussed it, I know it was discussed when we turned over, when we came in, but we didn't make any bones about it because we were interested in getting flow through the reactor and the bubble in the pressurizer and-so.
They had recovered from the building isolation high pressure injection.
They had recovered from that situation, and our concern was cooling the reactor and insuring it had flow.
Later on when we had things stabilized, we had a bubble in the. pressurizer and had a reactor coolant pump running and that term area, we were discussing with, I can't remember if it was one of our engineers.
But we did have a pressure spike.
We pulled it out and I don't know who wanted a copy but we made a couple copies of the chart.
"Q.
O.K.
This was sometime after 6?
"A.
Somewhere....
Hell, I_would say it was after 8:00.
"Q.
After 8:00 that night?
"A.
Yea, I'd say it was if I had to put a time on it.
"Q.
Were you there when they were talking about it?
"A.
Not when I came in.
I was there and I wasn't involved in any discussion until it was brought up....
Except when it was' turned over it was mentioned that we did have a pressure spike, when we turned over.
That was the only thing that was mentioned, and that they had recavered from reactor building isolation.
"Q.
So a pressure spike was. discussed at the turn over, when you first came in, about 3:45.
And then'somewhere about 8:00 further discussion and also xerox copies?
"A.
Right.
"Q.
And,apparently...
"A.
I think we remembered the xerox machine wasn't working too good.
"Q.
.At this_ time you discussed what-and with whom, if you can remember?
57
"A.
We talked, I' talked about it with the trainee on our shift, who was Chuck Mell.
And the person that asked for
'the information, and I don't remember who that was, whether it was an NRC inspector or a B&W representative.
"Q.
Was any discussion related to this?' Was the hydrogen burn or was a real spike or was this discussed as an electrica'l spurious signal possibly?
"A.
This was discussed that evening but we also talked about it several times after that and I cannot separate the two different discussions but as far as I remember we related it.to a cycling of the electromatic relief isolation, which is a DC operated valve I believe and that has a contact in there which will cause arcing which possibly could ignite the hydrogen.
That was discussed, but I can't say we di' cussed s
it that night.
We didn't really have that much time to do a lot of discussion, but we talked about it and when I walked away from the panel, the guy that wanted the copy, you know, he wanted it now, and I had to walk away from the panel to make sure that the other guy, my shift supervisor, was there while I walked away so...
"Q.
On the first evening, can you recall if on that first evening you were discussing after 8:00 that it was possibly a hydrogen burn?
"A.
As far as I know that possibility was discussed that evening.
"Q.
With this engineer, you don't know whether he was GPU or NRC or what?
Can you recall?
"A.
No, I won't say.
I don't remember.
No.
We...
It was also that night, you know, that we determined that we had a hard bubble and what that bubble was, you know, we had t'alked about that too, you know...
What is the gas and is it hydrogen or other and all that water that went through the reactor and out into the RC drain tank'and out into the reactor building.
.Illjes, I E 2 6.1., at 6-10)
(
NRC's IF invest'igation looked in'o Illjes's testimony t
and concluden that he was mistaken about. con'.ecsation relating to a hydrogen explosion having taken place.Wedaesday night--
that the discussion he recalled probably took place Thu'rsday night, when there was in -fact general discussion in the
~
58-
1 4
cpntr'ol room about a gas bubble and about the spike which had just been discovered by GPU engineers.
(NUREG 0600, p.
I-4-50, 51)
The Special Inquiry Group did not investigate this matter independently but examined the evidence gathered by the IE investigators -(including evidence specifically cited in the IE Report and other evidence) and concluded in our Report that IE's conclusion was correct.
(Report, volume II, part III, p. 147)
This conclusion was based upon the following:
.l.
No other control room operator or supervisor had -
recalled any general discussion in the control room about-i-
what caused the pressure spike or about a hydrogen explosion on Wednesday night (i.e., afte.r the main pumps were restarted about 8:30 p.m.), whereas such discussions clearly did take place Thursday night when engineers discovered the spike, cut up the strip chart, and Xeroxed it in order to analyze it.
2.
Illjes recalled that "we also talked about it
'several times after that and I cannot separate the two different~ discussions," (Illjes, IE-261, at
),
suggesting that he, like others, may have had a difficult time long after the fact distinguishing between events that occurred on Wednesday and Thursday.
3.
In his testimony, Illjes linked the discussion about the pressure spike with the determination that there was a noncondensible gas bubble in the reactor system ("It was also that night, you know, that we determined that we had a hard bubble and what that bubble was, you know, we had talked about that too, you know").
The presence of non-condensible gas was not discussed, as.far as all the evidence available to us showed, until late afternoon or early evening on Thursday, not on Wednesday night.
4.
Illjes made reference to requests for information from GPU. engineers or NRC inspectors.
We. knew such individuals had been involved in looking at the. pressure spike Thursday night, but there was no evidence that either GPU officials
~
or NRC, inspectors knew of or were' interested in it Wednesday night.
5.
The strip chart in question bears a notation that it was removed'from the rotating drum in the control room _at about~ noon on Thursday, and the two pen-recorder lines run out to approximately that time.
In order.to xerox the spike Wednesday night it would have~been necessary to remove the 59
-w
-- y6
l i
l i
entire drum from the instrument panel, interrupting both-pen lines.
An IE inspector who examined the original chart reported in the IE investigation report that it showed no discontinuities of the type that would'necessarily be caused by taking the. chart off the recorder and putting it back on again.
J 6.
IE interviews with two other individuals present in l
the control room, which were not specifically cited in IE's investigation report, did not corroborate Illjes's recollection.
i In his testimony, Illjes said that he had discussed the possibility of a hydrogen. explosion with trainee Charles Mell.
l Mell, in an IE interview, recalled being told about the pressure spike when he came on duty with Illjes, but recalled that there had been no discussion of a possible hydrogen i
explosion until Thursday night, when someone else postulated such an event.
(Mell, IE 335, at 11-12)
Richard Lentz, a GPU Design Engineer, was using the xerox machine in the control room during most of the evening and for at least two solid hours after 8 p.m. to make copies of alarm printer print-outs.
He recalled that no strip chart data was l
xeroxed that night--that strip charts were taken off the next day and put in envelopes, per company polf.cy.
(Lentz, IE 298, at 6-7, 9, 15)
For the purposes of exploring this issue as completely as possible, additional-interviews have been conducted by the Special Inquiry Group.
These interviews do not rule out the possibility that there was some discussion in the control room on Wednesday night about a hydrogen explosion having caused the pressure spike, but they do lend additional i
corroboration to the conclusion that Illjes is probably mistaken about the day on which the conversations occurred.
The IE inspector who examined the original strip chart for discontinuities in the lines of the two pens (one narrow range, one wide range), Anthony ~Fasano, was interviewed and stated that whether the graph or the entire drum was taken off the console for xeroxing,.it would be necessary to remove both pens from the paper and then later replace them on the paper..His examination had detected no dis-continuity or even any spot of ink on'either pen line of the t
strip chart for the time (Wednesday evening) when Illjes said it was removed for Xeroxing, or~any.other time.
Illjes, interviewed by the Special Inquiry Group, stated 60 I
4 that it was still his best recollection that there was discussion about a possible hydrogen explosion on Wednesday night and that at the same time he believed that the entire strip chart was taken off the console and taken to be Xeroxed.
Illjes recalled that this was done because."a number of engineers" requested the strip chart and that he talked to one of these engineers, Bubba Marshall, about whether the j.
spike had been caused by an electrical spi-he or a hydrogen.
explosion.
(Illjes, SIG Interview Memorandum, 2/22/80)
During this interview, Illjes had the original strip chart in front of him.
He verified that the note on the chart stated that it was not removed until noon on March 29 and appeared to have run until that time.
Illjes further stated that upon examination of the chart, it did not appear that it had been removed prior to that time.
Asked whether it would be possible to remove the chart and replace it without causing any discontinuity in the pen lines, Illjes stated that if one was trying very hard to do it so that no discontinuity would be detected, it might be possible, but otherwise it would probably not be.
(Id.)
Bubba Marshall, the engineer Illjes identified as having I
discussed with him the possibility of a hydrogen explosion on Wednesday night, was also interviewed.
Marshall stated that he was present Wednesday night and Thursday morning until about 7 a.m. in the vicinity of the control room; that he had previously been present at 2 p.m. when the spike occurred, and that at that time it was. generally agreed to have been caused by a faulty signal; that on Wednesday night, there was no discussion about the possibility of a hydrogen explosion; and that he was involved in discussions on Thurs-day night after 10 p.m. with Dick Bensel, Jim Floyd and control room operators about the pressure spike and a hydrogen explosion.
(Marshall, SIG Interview Memorandum 2/22/80)
John Kidwell, Illjes's fellow control room operator who was on the same shift Wednesday and Thursday night, was interviewed.
He stated that Wednesday, Thursday and Friday nights all blurred together in his mind.
He recalled that there was discussion late one night about the' pressure spike and what caused it, but-did not know which day.
He never recalled on any of those evenings an occasion when the reactor building pressure strip chart was taken off~its drum in the control room console to be Xeroxed.
(Kidwell, SIG Interview Memorandum, 2/22/80)
Charles Mell was also interviewed.
He stated that he did not believe there was any discussion on Wednesday night 61
of a possible hydrogen explosion.
He stated that the only person he heard discussing such a possibility was Bubba Marshall, and that that occurred on Thursday night when the engineers were examining the strip chart and trying to analyze the size of the bubble.
(Mell, SIG Interview Memorandum, 2/22/80) i In sum, then, while some discussion in the control room e
about a possible hydrogen explosion on Wednesday night obviously cannot be completely ruled out, Illjes's recollection is rebutted by the available documentary evidence (the strip chart), by the testimony of Mell and Marshall (who say'the conversation did not take place Wednesday night but Thursday night), by the testimony of Kidwell (who says he does not believe the strip chart was removed for Xeroxing), by Illjes's own recollection that a bubble of noncondensible gas was discovered and in the process of being analyzed on Wednesday night (in fact, it was Thursday), and by the fact that other aspects of what Illjes recalls indisputably took place Thursday, rather than Wednesday, and that there is no evidence except Illjes's that similar activity ever took place Wednesday night.
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' QUESTION 10, FIRST SET "10.
Did bbc. Miller and/or other Metropolitan Edison officials have an obligation to report on March 28 any or all of the following to State and Federal officials:
-- in-core thermocouple data indicating i
- temperatures in excess of 2000 degrees F.;
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-- computer printouts of in-core thermo-couple voltages indicating presence of super-heated conditions (and partial core uncovery);
-- hot-leg temperatures indicative of superheated conditions prevailing for most~of the-period between 6:00 a.m. and 8:00 p.m..
-- the pressure pulse recording and other manifestations of a hydrogen detonation in the containment at 1:50 p.m.; and
-- uncertainties during the day as to whether the core was covered?
At the outset, two caveats should be noted.
First, the Special Inquiry Group did no'. Jndertake in its Report, nor l
does it now undertake to rendes any judgment about whether licensee officials breached a 2 agal obligation to provide in-formation to the NRC.
This is 1 decision that the agency itself must make and that-only it can make.
We are under-taking, rather, to cite factual information and considerations 4
j relevant to the above-quoted question.
i 4
Second, the Group did not perform a detailed search for legal or regulatory requirements that might pertain to such reporting, nor does this answer purport to advance any legal-I analysis of that issue.
l From a cursory review, it appears that there are probably no formal or legal requirements'that explicitly i
obligate a licensee to report the items listed in the question, within a time frame cxE minutes or hours, during the course _ of, an ongoing accident.
The items listed are symptoms cxE a-damaged core or, taken in the context of-March 28, at least I
indications that the core might be damaged.
Such indications 1
would' require reporting t'o the NRC of:the possible condition --
the damaged core --- under the reporting requirements of the 63 e
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s.m,
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plant's technical specifications, or, conceivably, 10 CFR Part 21.
However, those requirements appear to be written in terms of day-to-day operations, rather than an ongoing accident.
The tech specs speak of initial reporting within one or two days, and follow-up reports later on.
9 Here, the initial report of a general emergency and some radiation readings had already indicated the. possibility of a t
damaged core.
Men Ed's emergency plan required initial' noti-fication of State and Federal officials, and updates on the course of the accident with emphasis on releases of radio-active material and dose rates at various locations.
This was being done.
As in the case of the NRC's reporting requirements, there appear to be no specific requirements in the emergency plan to report these specific items within a time frame of minutes or hours.
4 t
j Nevertheless, it might be argued that from the total scheme of regulation -- or from common sense -- a practical obligation could be inferred that if, during the course of an accident, indications of serious problems arise, they 4
l should be reported to Federal and State officials.
Such in-dications are pertinent to these officials' responsibilities which is the basic reason for the notification and reporting requirements of the technical specifications and the emergency plan.
Assuming such a common sense or implied obligation, we l
believe some or all of the above indications should have been reported to the NRC.
l, With respect to the State, inferring an obligation to report these specific items is somewhat more difficult, since the primary reporting obligations would appear to center on actual and projected off-site radiation dose rates.
Good communications were established between the plant and State officials.early on March 28 (and maintained i
i thereafter) to provide such information.
It is doubtfu' that many of the indications listed in the question'wer; specifical.'.y reported to_the State on March 28; we'did not find mention of them in~ state telephone logs or the testimony l
of State officials, but then we did not specifically focus on questioning of State officials as to when they first-l l
learned of these indications.
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In-core thermocouple readings by technicians Specific in-core thermocouple data indicating reported temperatures in the core of 2400 or 2500 degrees apparently were not reported to the NRC.
As pointed out in detail in the ans'wers to Questions 1, 3, 4 and 5, First Set, and Questions 1 through 4, Second Set, this information was given by lead instrument control engineer Ivan Porter to Station Manager Gary Miller, and both have,said they did.
a
^
not believe the accuracy of the readings.
The discounting of the readings was also confirmed in testimony by Operations Supervisor Michael Ross and B&W Site Representative Lee Rogers.
The readings apparently were not known to others in the control room, since the technicians who took the l
readings evacuated the area before NRC inspectors arrived, and were not discussed in later emergency command team meetings at which NRC inspectors were present.
Thus they were not r
'lly available to NRC inspectors on-site on March 28.
Miller has testified that he was not aware of requests for such information from the NRC (Miller, SIG.
l Depn., 11/29/79, at 9-10)
Those asked for the information were not aware that the technicians had taken the specific i
information from the thermocouple lead wires earlier in the morning.
It would appear that the obligation to report such read-ings would have rested on Gary Miller as the senior official in the control room who was in charge of the plant.
6 The central question is whether, assuming that the sworn testimony of Miller, Porter, Ross and Rogers is ac-cepted as true, there being no direct evidence to impeach that testimony, Miller had an implied obligation to report these readings to the NRC even though he doubted their accuracy.
This appears to us to be the question that is appropriate for the NRC itself to address and answer in'the context of enforcement or other regulatory activity.
l Computer print-outs of in-core thermocouple readings These readings were generally available in the control room'and were available to NRC inspectors present there.
The fact that most of the readings were off-scale was reported to NRC officials in telephone conversations by early after-noon on' March 28, and perhaps earlier.
Thus it appears that these readings can be said to have been reported to the NRC.
If in fact there were on-scale thermocouple' readings obtained-from the computer during the. day,_we found no evidence that these numbers were reported to NRC officials off-site.
65 l
Hot leg temperatures These readings were well known in the control room, were available to NRC inspectors in the control room, and were re-i ported to NRC officials off-site.
They were also discussed in emergency command team meetings in which NRC inspectors participated.
Thus these readings were reported to the NRC.
~
~ The pressure pulse recording
~
The factual details of who knew what about the pressure pulse recording on March 28 are recited at length, with cita-tions to relevant testimony, both in our Report and in the answers to Questions 6, 7 and 8, First Set, and Questions 5, 6, and 7, Second Set.
If it had been recognized that the spike was indicative of a hydrogen explosion in containment, clearly this informa-tion should have been reported if any implied reporting.obli-gation should be found to exist.
Station Manager Gary Miller has said he was not aware of the spike at the time, but others have testified that he was, and it appears more likely than not that he was made aware of it.
However, with the ex-ception of two shift supervisors, Joe Chwastyk and Brian Mehler, all of the others in the control room at the time who admit being aware of the spike agree that it was dis-l counted as an instrument malfunction or stray electrical signal.
NRC inspectors were present in the control room at the time the spike occurred (which involved not just the I
spike itself but an actuation of safety features including building spray and high pressure injection).
A number of witnesses have testified that NRC inspectors observed the spike itself, but we were unable to locate any such inspec-tors who recalled being aware of it, and it was not reported to NRC officials at Region I or in Bethesda.
The only individual who has acknowledged awareness of.
a possible hydrogen explosion on March 28 is Joe Chwastyk.
Chwastyk believes, but is not certain, that he related his conclusion to Gary Miller, which would have placed an obliga-tion to report this information on Miller.
Miller has testi-fied he was not told of a possible hydrogen explosion that day and that the presence of that amount of hydrogen in the containment never entered his mind.
In any event, Chwastyk also testified that he related his conclusion in some detail to an NRC inspector.
66
Uncertainties as to core covery Since these concerns were discussed in the emergency command team meetings in the presence of NRC inspectors,-
they can be considered to have been reported.
67
QUESTIONS 1, 2 AND 3, SECOND SET "1.
What inference is to be. drawn from the disparity of recollections concerning the significance of the incore thermocouple me~asurements made prior to 9:30 a.m. on March 28, 1979; e.g. Messers.Bennett (I&E L
Tape #311, p. 18-19), Wright (I&E Tape #310, p. 18),
and IMB (I&E Tape-#315, p. 18). recall informing Mr.
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Porter that they believ'd the temperature ~ data to be e
indicative of the core being. uncovered while Mr.
Porter has made inconsistent statements sometimes i
implying that he did not believe the readings and other times suggesting that, "I guess I was afraid it was real."
(I&E Tape #237, p. 20.)
Does the pre-ponderance of evidence support the recollections of Messers Bennett, Wright and IMB, that it was generally agreed by them that the incore data was valid and indicative of the core being uncovered or does the preponderance of evidence support the recollections t
of Mr. Porter to the effect that he at the time I
concluded the data was probably invalid?
"2.
What specific statements did Mr. Porter make lead-ing to the statement on page 30.of the report of the Special Inquiry Group that, concerning the incore thermocouple readings, " Porter shrugs
. off [the readings] and returns upstairs to brief Miller.
He tells Miller of the readings, but says he does not believe the high ones are accurate.
"?
"3.
If Mr. Porter concluded that the incore thermo-couple data was unreliable, what did he believe to be the source of this unreliability?
Was Mr. Porter's explanation of the malfunctions of the thermocouples i
consistent with the fact that the thermocouple data was recalled from the computer several times on March 28 and the following days apparently (according to John Flint) because this data was indicative of what was happening to the core; e.g. if the thern.acouples had become unreliable by 9:00 a.m. on March 28, what would have happened to increase their reliability thereafter?
If the thermocouples were unreliable because of~their having been overheated, what
-temperatures would they have had to experience in order that multiple junctions be formed?
What would
~
have been the'cignificance of these temperatures?
Was a cause'of formation of multiple junctions discussed with Mr. Gary Miller and if so, what was R
the outcome of such discussion?
68
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The answers to questions 1 and 2, and to most of question 1
3, are covered extensively in Volume II of our Report, part I
III, pp. 131-138.
f As our Report points out, with citations to appropriate testimony (id. at 133-134, footnotes 25 through 33 inclusive),
three of the men present during the time when the first readinos were taken off the wires told IE interviewers that I
.~
~they recall'ed a comment being mad'e in'PorLer's presence-about the high temperature readings indicating that the core was or had been uncovered.
Yeager recalled that after taking some initial readings, he turned around and told l
Porter that "the core is uncovered.
Okay, Mr. Porter kind j
of doubted our word and didn't believe the readings, and says,
'I don't believe your readings.'"- He also recalled that they confirmed these readings with a second instrument --
l
- a. voltmeter -- before Porter left.
Yeager testified:
l "I believe Ivan didn't want to believe what was taking place.
I don't know whether it was an attitude of l
' Hey, your measurements are wrong--you guys don't know what the heck you're doing'--or whatnot.
I think the general consensus throughout the whole first day was, number one, nobody really knew what was actually happening, number two, some that had an inkling of what was happening didn't really want to believe what was going on."
Wright recalled to the IE investigators that after the technicians had taken about five readings, one or two of which were around 200 and one or two around 2100, Porter ap-peared on the scene, and that Porter's response was that "the data didn't look too good."
Wright recalled that Porter said, "There's some there that are, that look too high.
that look like they'd been damaged."
Wright also remembered Yeager saying to Porter that the core was uncovered.
Skip Bennett also told IE interviewers that he believed the subject of the core being uncovered came up in Porter's presence:
he recalled that "they" made a statement to Porter that the core possibly had been uncovered.
Wright also stated that it was his personal view that while the high temperature readings could have been inaccurate, it was more likely that_the core had been uncovered and then i
recovered, and that the temperatures were very slowly coming down.
Bennett said to the interviewers that he recalled " concern or disbelief" at the high readings, but that at that same time it was his feeling that-Porter himself l
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[
69
was "more or less in agreement" with everyone else about the possibility of core uncovering.
Porter, in a deposition conducted by the Special Inquiry Group which focused on this particular subject (Porter, SIG Depn., 10/30/79, passim) testified that he did not recall such a comment having been made but that it was possible that it had been made.
(Id. at 10, 24)
'orter also-
+'
confirmed the accuracy of earlier testimony he gave in an IE interview in which he testified as follows:
"Q.
So, you don't recall if Mr. Wright if Mr.
Bennett, or Mr. Yeager ever told you together or separately that they felt that temperature indications indicated the core was uncovered?
"A.
I don't specifically remember them saying that, no.
I'd.
I think everybody involved with it was probably concerned about the water level and they were seeing, seeing the temperatures we were seeing but I guess I don't recall if of [ sic] anybody stating that specifically.
But, I might of myself, I guess.
I just don't recall that clearly, right now, what anybody said at any given time."
(Porter, IE 324, at 6)
In the Special Inquiry Group's deposition, Porter was read the testimony of the other three men on the record and specifically asked whether that refreshed his recollection and whether he recalled any such discussion having taken place.
Porter, SIG Depn., 10/30/79, at 20-24)
Porter again answer d that he did not specifically recall such discussion, but that it might well have taken place.
Question 1 of the Second Set seems to suggest that there is a discrepancy between the testimony of Porter and the others; in fact, Porter did not deny their testimony and said that such comments as they recalled may well have been made.
The weight of the evidence clearly indicates that such discussion probably did take place, and there appears to be no reason to doubt that it did.
In answer to Question 2, Porter's testimony and reason-ing is also discussed at some length in Volume II, part III of our Report, at 133.
Porter has discussed his reasoning in several'different interviews: IE 324, at 6-9; IE 237, at 18-22; SIG Depn., 10/30/79, at 11-12, 18-20, 29-33, 38.
Porter's own testimony concerning the fact'that he did not believe the accuracy of the high in-core thermocouple readings, 70 1
9 and the testimony. discussed above of the instrument technicians and foremen concerning Porter's reluctance to believe the accuracy of these readings, which tend to. corroborate Porter's testimony about his thinking at the time, together form part of the basis for the statement in Volume I of our Report, p.
30, that Porter " shrugs off" the readings and reports them to Miller, but tells Miller he does not believe the-high figures are accurate.
The re~st cf the basis for this statement is the testimony of both Porter and Miller about the conversation between them (Porter, SIG Depn.,
l 10/30/79, at 11-12, 38; Porter, IE 237, at.19-20; Miller, SIG Depn., 10/29/79, at 3-5) and the testimony of Mike Ross (Ross, SIG Depn., 9/18/79, at 23) and Lee Rogers (Rogers, SIG Depn., 10/11/79, at 29-30) that the high thermocouple.
readings were dismissed as inaccurate.
4 In answer to Question 3, Porter's thinking about the reliability of the in-core readings is set forth in IE 324, at 4
6-9; IE 237, at'18-22; and SIG Depn., 10/30/79, at 7-8, 11-12, 18, 20, 29-38.
At various points in this testimony Porter stated that among the possibilities were that the thermo-couples were " destroyed," that moisture in the building may have affected the readings, that some of the junctions may I
have been open, or that junctions may have melted and fused together, producing cumulative voltage signals--particularly if multiple' metals were present.
Question 3 further asks whether Porter's thinking was
" consistent" with John Flint's testimony about the monitor-ing of,the in-core thermocouples throughout the rest'of the day.
Porter's conclusions may have been grossly incorrect, but as pointed out above.in the answer to
)
Question 2, First Set, Flint has testified that he was not I
aware that high readings had been taken with a digital voltmeter from the in-core thermocouple leads, and that he j
was doing the " monitoring" of the in-core computer readings by himself; therefore,-the testimony is not " inconsistent."
i Porter himself testified that he was involved in taking I
further-in-core readings on Thursday and Friday and in
' discussions with NRC: personnel-and Met Ed' consultants' regard-l ing the accuracy and integrity of the in-core thermocouples on those days.
'(Porter, SIG Depn. 10/30/79, at 31-38) f f
. Subsequent investigation-by'the NRC explored the possibility of multiple junctior.s having been formed, and.
the results thereof.
The melting-temperature of the Chromel'-alumel-thermocouple-material itself~is about 2700 degrees F.
In addition,- it' hat, been' suggested that u
. 71 '
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thermocouple leads could'hecome fused, creating multiple junctions resulting in high voltages, and that this phenomenon has been observed in an ORNL research reactor.
Several other possibilities have been suggested.
(See Memorandum from B.
Snyder, OPE, to Commissioner Gilinsky, Sept. 27, 1979, entitled "TMI Accident--High Temperature. Readings from Core i-Thermocouples.")
We are not aware of any further results of t ' ' -
- this NRC inquiry.
-~
s Obviously, if the alloy itself melted, it would imply that actual core temperatures would'have to have reached 2700 degrees or above.
In two depositions conducted by the Special Inquiry Group, Gary Miller was interrogated about whether knowledge of melting would not in and of itself have told him that the readings he received from Porter were fairly accurate.
This testimony was quoted above, in answer to Question 1, First Set.
Miller's testimony about what Porter told him with respect to the melting of junctions is also set forth in that answer.
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QUESTION 4, SECOND SET "4.
On page 138 of Volume II, Part 3 of the report of the Special Inquiry Group it is 7
stated that, "It is not clear that any of the actual (incore temperature] readings were communicated to the NRC on March 28, despite p.
requests for such information.,_ althot 7h Ahe
~
general range of readings may have been trans-mitted."
Why is it not clear that the read-ings were communicated to the NRC?
What is meant by the statement that the general range of readings may have been transmitted?
Which of the incore data obtained by the instrument technicians was transmitted to the NRC?"
The sentence quoted in the question, which is part of a summary paragraph in our Report, reflects a full single-spaced typewritten page of discussion of evidence contained on the previous page of the Report concerning NRC knowledge of in-core thermocouple temperature readings.
It is not clear that any " actual" in-core readings were communicated to the NRC on March 28 because, as stated on the previous page, there is no evidence that the readings taken-by the instrument technicians that morning were ever related to the NRC.
However, there were NRC inspectors in the Unit 2 control room throughout the day who had access to the instru-mentation computer, on which there is evidence that thermo-couple temperatures were periodically printed.
Any on-scale thermocouple readings such as those described by B & W engineer John Flint (see above answer to Question 2, First Set) and any question marks printed by the computer may therefore have been r
observed by NRC inspectors.
As the Report also discusses at length, there were re-quests from NRC headquarters in Bethesda during the day for information about in-core thermocouple readings.
It may be that the general range of these readings, i.e., that some or all of-the'in-cores were reading off-scale on the computer, (above 700 degrees F.), was reported to NRC Wednesday morn-ing.
(See',
e.g., testimony of Victor Stello before Congress-man Udall's Subcommittee in May, 1979, Hearings, Part I, at 12-13.)
However, other evidence including contemporaneous tape' transcripts suggests that this information was not known in Bethesda until Wednesday afternoon.
73
l I
l Stello testified Ecfore the Udall Subcommittee that it was the fact that the in-cores were generally in the range above 700 degrees (which was above saturation at pre-valling system pressures) that persuaded him that the core was badly damaged.
(Id. at 12) l
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74
QUESTION 9, SECOND SET "9.
Did any of the persons at Three Mile Island on March 28 seek to infer from the containment radiation levels, as had,been done by Mr. Floyd in Lynchburg, an estimate of the number of fuel rods that had cracked
~
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~
or ruptured?
What did TMI staff diagnose as the source of such radiation?
Who at TMI had made such estimates or diagnoses on March 287 If such estimates or diagnoses were not made, what was the reason for not doing so?"
James Floyd, Unit 2 Operations Supervisor, was at Babcock & Wilcox in Lynchburg, Virginia, for training on March 28.
He has testified that upon receiving information about the high radiation reading registered by the contain-ment building dome monitor, he used technical information j
available at B&W on another plant's (presumably similar) radiation monitor to calculate the probable total amount of radioactive material released into containment.
From this, he arrived at a rough estimate that one-eighth of the " full gap activity" had been released by the fuel rods.
(Floyd, Pres. Domm. Depn., 8/1/79, at 159-161)
Floyd testified that he never transmitted this information back to Three Mile Island personnel, assuming they could make the same deduction themselves.
Apparently no one at the TMI site attempted to make a similar calculation.
A number of Met Ed and GPU supervisors were asked specifically about this subject in depositions conducted by the Special Inquiry Group.
For instance, Shift Supervisor Brian Mehler testified that he did not believe one could calculate the amount of core damage from the fact that the dome monitor was pegged high.
(Mehler, SIG Depn.,
10/11/79, at 13)
Shift Supervisor Joe Chwastyk testified that in general it is not possible to correlate point radia-tion dose readings with amounts of core damage.
(Chwastyk, SIG Depn., 10/11/79, at 27-28)
Robert Arnold, GPU Vice Presi-dent, testified that he thought that moisture in the contain-ment had caused the monitor to fail and that the monitor's readings were discounted at least until Sunday night, April 1.
(Arnold, SIG Depn., 9/24/79, at 5-6)
Other supervisors expressed views similar to those ar-ticulated by Gary Miller before Congressman Udall's Subcom-mittee (Hearings, Part I, at 184) that he did not think of I
l
-75 l
the containment dome readings in terms of fuel damage as much as in terms of what dose rates might be expected outside the plant, both on-site and off-site; and that the possibility that moisture and/or a break in the monitor's shielding might be resulting in unreasonably high readings led to the readings being suspect.
See SIG Report, Volume II, part III, p.
- 130, re George Kunder and Richard Dubiel; see also Miller, SIG Depn., 10/29/79, at 14-16; Miller, Pres. Comm. Depn., 8/7/79, 3,
at 287; Chwastyk, SIG Depn., 10/11/79, at'59-60)
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It was the escalation of the readings in the dome monitor that gave rise to the decisration of a general emergency, and the readings on the monitor were promptly reported to the NRC.
i (There is no evidence that anyone at the NRC attempted a cal-culation on March 28 like that made by Floyd.)
Early estimates of probable off-site dose readings made on the basis of the l
high dome monitor reading were not borne out, as our Report discusses in some detail at pp. 127-131 of Volume II, part III.
The monitor itself is encased in lead shielding designed to reduce radiation strength by a factor of approximately one hundred.
Apparently Met Ed personnel believed the shielding had been penetrated or that moisture had rendered the monitor inaccurate.
This was an evaluation shared by NRC staff in their briefing of the Commission Thursday morning, March 29.
In general, it appears that the radioactive materials known to be in the reactor coolant (and in the containment building due to leakage through the PORV) were believed by everyone on March 28 (including Floyd) to be due to release of fission product gases ordinarily contained within the fuel rod cladding and released when cladding cracked or fuel " pins" popped in response to rapid, substantial changes in temperature and pressure.
For example, B&W engineer John Flint, one of the very few wao has testified that he believed the core had been uncovered early Wednesday morning, explained in an IE inter-view that even he did not suspect more serious damage on March 28 than release of. gap activity through cracked clad-ding due to violation of the pin compression limits.
(Flint, IE 323, at 13-16)
(See also, e.g., Floyd, Pres. Comm. Depn.,
8/1/79, at l'59-161; Mehler, SIG'Depn., 10/11/79, at 23) 76
QUESTION 10, SECOND SET "At what hour did it become apparent to Messers Miller and Herbein that attempts to depressurize the system had been unsuccessful?
Was the fact that the depressurization effort did not appear to be succeeding reported to Lt. Governor Scranton?
Who made theidecision to repressurize the system?
At what hour was t-this decision made?
Who particip~atet in the
~#'
discussions leading to the repressurization decision?"
This question is a,nswered in the discussion in our Report of the operational reaction to the accident, Volume II, part III, pp. 33-45.
The cited pages discuss in con-siderable detail the decision to depressurize the plant made at about 11:30 a.m.; the decision to send on-site supervisors to Harrisburg in early afternoon; and the decision to re-pressurize the reactor coolant system made at about 5:30 p.m., all with citations to the relevant testimony.
The Report sets forth the reasons for each decision and its pros and cons, as evaluated in hindsight.
The decision to depressurize the plant was made at about 11:30 a.m. because of (a) failure to collapse the steam voids under high pressure; (b) concern that high pressure injection water might be bypassing the core; (c) desire to alleviate uncertainties about core covery by bringing the core flood tanks to bear; and (d) a desire to move closer to eventual use of the low pressure decay heat removal system.
Shortly before 2 p.m., when Station Manager Gary Miller and Superintendent-Technical Support George Kunder left for Harrisburg with Jack Herbein to brief Lt. Governor Scranton, Miller observed a small drop in the core flood tank level (indicating to control room personnel, erroneously, that the core had been thoroughly covered) and a small decrease in hot leg temperatures.
These observations led Miller to conclude that they were beginning to have success with the depressurization strategy.
(Miller, SIG Depn., 9/20/79, at 24-25, 27-30, 42; Miller, IE 158, at 23)
Miller's optimistic assessment that the plant was " reasonably" though not
" finally" stable and they were "in a set of steps that would bring us" to a stable condition (Miller, SIG Depn., 9/20/79, at 27-30) was conveyed in substance to the state officials by Jack Herbein, although the emphasis in the briefing was on off-site radiation dose measurements and the dumping of 77
3 t
ste'am.
(See Herbein, SIG Depn., 9/19/79, at 35-37; SIG Re-
_ port, Volume II,'part III, at 383-384.
According to Herbein, "I thought [the plant] was stable.
I guess I thought the core was covered.
That we were proceeding in a logical direction.
And that before the day was out we would be down_on forced low pressure, or decayed heating coolant."
State officials t
have stated after the fact that they were not satisfied with j
the briefing and were not sure they were ghtting complete 9
information.
(Gerusky, SIG Depn.,_9/19/79.. at 31-32) i The decision to repressurize the system was made by GPU Vice President Robert Arnold and Met Ed Vice President Herbein in a telephone conversation between the two about i
i 5 p.m. on March 28, after Herbein had returned to the TMI i
Observation Center from Harrisburg.
Arnold discussed plant operation with Herbein and strongly recommended that the plant be repressurized and j
that a reactor coolant pump be started.
They agreed on this course of action and Herbein agreed to direct the plant staff to carry it out.
Herbein recalled major reasons being the steam in the hot legs and the lack of success in an earlier j
attempt to depressurize and operate the decay heat removal system.
(Written Met Ed submission from J. Herbein to SIG, 8/7/79)
Arnold also recalled that an important consideration was the desirability of returning to a mode of operation that they understcod well.
(Arnold, SIG Depn., 9/24/79, at 20-23)
Herbein either won Miller over or, in effect, imposed l
l this decision on him, notwithstanding the opinion of the i
control room staff that progress was being made with the low pressure strategy and that it should be allowed to con-tinue.
The information and advice available to Arnold that caused this telephone call to be placed are discussed at.
great length in our Report, Volume II, Part III, at 43-45, with citations to relevant testimony.
To summarize the evidence, Arnold first learned of high radiation readings and began to suspect the existence of fuel damage in the late morning of March 28.
By about 2:00 p.m. Arnold's staff told him of their concern that the reactor. coolant system was not solid, that is, that there was a steam bubble in the system outside_the pressurizer, implying.that the core was uncovered or was not being cooled effectively.
Arnold recalled that this was based on data'his staff had obtained. independently from the plant rather than through Arnold.
Shortly after 2:00 p.m., in a telephone conversation, Arnold expressed _ concerns to Lee Rogers in the control room 4
' about steam in'the reactor coolant system implying-an un-
.covesadicore. LRogers responded'with the plant staff's 78 e
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-"T=*r T'-
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. conclusion that the core was covered.
Arnold did not believe that this was unreasonable.
At the time of this call, Miller and Herbein were absent for Lt. Governor Scranton's briefing in Harrisburg.
After the call, Arnold's staff discussed their concerns further with him.
In particular, they emphasized concern that steam bubbles in the system may not Have been collapsed.
These conversations increased Arnold'g_co3cern and he decided 5
to press more forcefully for corre5tive acti'on.
Arnold later spoke with Herbein and emphasized the corrective action recom-mended by his staff.
Although Arnold was now very concerned about steam in the system and a possible uncovered core, it did not cross his mind that core damage had proceeded to such a point that a metal-water reaction had occurred or was pro-7 ceeding, according to his testimony.
Further testimony taken by the Special Inquiry Group con-cerning activities by Arnold's staff is recounted at p. 44 of Volume II, part III, of our Report.
At the outset of our investigation, we believed that the decision to repressurize the system -- which ultimately brought the reactor to a stable cooling mode -- had been made in part due to prompting by B&W and/or NRC officials.
However, our investigation showed that NRC never made any such recommenda-i tion (tape transcripts reveal only discussions about NRC sug-gestions to depressurize the system) and that B&W officials called GPU personnel in New Jersey only to convey their recom-mendation that high pressure injection flow be kept at or about 400 gpm, not to recommend repressurizing the system.
Therefore, it appears that the decision to repressurize was solely that of Met Ed and GPU personnel.
Gary Miller has testified that the decision to repressur-ize the system was, in the final analysis, made "inside" the plant, though with " strong advice" from Herbein and Arnold.
(Miller, SIG Depn., 9/20/79, at 33)
Arnold was also reluctant to say that he " ordered" Herbein to adopt this strategy, calling his view a " strong recommendation."
But he does recall expressing to Herbein "that he should insist upon it if there was a r'eluctance on the.part of th. plant."
(Arnold, SIG Depn., 9/24/79, at 22)
However, the control room staff did believe that progress was being made with the low pressure strategy and that such progress could be continued.
The i
total impression we gained from the evidence was that while l
Miller may have been won over to a repressurization strategy in rational discussion, Herbein, as Miller's superior, would l
l 79
- have instructed Miller to adopt such a course had it become necessary.
This impression is summed up in Mike Ross's re-counting of Miller's instructions to him after the decision was made.
"He said, ' Jack wants it solid and he wants it now, so please do it.'
And I did."
Although the decision to repressurize; was caused in part by the perception that the low pressure strategy was t-
. not working, it is not clear that-the low pressure strategy would not in fact ultimately have succeeded.
Repressuriz-ation did lead to a stable method of core cooling.
The Special Inquiry Group attempted to determine, in one of its alternative accident sequences, what might have occurred had the pump not been r& started.
(See Alternative Sequence II-D-2.ll, Report, Volume II, part II, p. 329)
Some data suggest that progressive cooldown might have occurred and continued, but the computer code analysis did not give sufficient information to conclude whether the repressuriza-tion strategy was in fact a critical event or not.
e 80
~
-0UESTION ll, SECOND SET "11.
In a May 9, 1979 mailgram to me, Mr.
Herman Dieckamp, President of General Public Utilities Corporation, stated:
'There is no evidence that anyone interpreted the ' pressure spike' and the spray initiation in terms of reactor core damage at the time of the spike F.
nor that anyone withheld any inforcat.on.'
J
_.c Prior to sending ma this mailgram, what steps had Mr. Dieckamp taken to determine whether any of the TMI supervisors had interpreted the pressure spike and spray initiation in terms of reactor core damage?
Is J4r. Dieckamp's statement quoted above consistent with the recollections of Mr. Chwastyk that he (Chwastyk) had recognized that the pressure pulse was real, that it was probably a manifestation of a hydrogen explosion, and that this was an in-dication of severe core damage?"
The Special Inquiry Grcup does not know and did not ask specifically in any deposition what steps Mr. Dieckamp may have taken prior to sending the May 9 mailgram to Con-gressman Udall to assure himself of its accuracy.
The first half of Mr. Dieckamp's quoted statement is obviously inconsistent with Mr. Chwastyk's subsequent testi-mony, which was taken by the Special inquiry Group in October 1979.
(With respect to other testimony concerning this matter, Mr. Illjes was first interviewed by IE investi-gators on May 23, 1979, and Mr. Chwastyk on May 21, 1979.)
l 81 I
l