ML20235B149
| ML20235B149 | |
| Person / Time | |
|---|---|
| Site: | Sequoyah  |
| Issue date: | 09/11/1987 |
| From: | NRC |
| To: | |
| Shared Package | |
| ML20235B130 | List: |
| References | |
| NUDOCS 8709240006 | |
| Download: ML20235B149 (72) | |
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TRANSCRIPT OF PROCEEDINGS UNITED STATES NUCLEAR REGULATORY COMMISSION In the Matter of:
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FINDINGS FROM THE INTEGRATED DESIGN
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INSPECTION (IDI) AT TVA
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Pages:
1 through 71 Place:
Knoxville, Tennessee
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Date:
September 11, 1987 Heritage Reporting Corporation iCIGi EtPotters 6709240006 B70915 1220 L Stat. N.W.
PDR ADOCK 05000327 G
PDR Washington. D.C. 20005 (202) 628 4888 s_---______
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l' UNITED STATES NUCLEAR REGULATORY COMMISSION
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3 In the Matter of:
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4 FINDINGS FROM THE INTEGRATED
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H DESIGN INSPECTION (IDI) AT TVA.
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Friday 7
September 11, 1987 8
TVA West Tower I
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400 West Summit Hill Drive 9
Knoxville, Tennessee j
l 10 The above-entitled matter came on for hearing, l
i 11 pursuant to notice, at 8:58 a.m.
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12 13 PRESENT:
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14 JOHN A.
ZWOLINSKI J
BRYANT M.
LOWERY j
15 B. D.
LIAW l
GARY ZECH 16 JANE A.
AXELRAD JAMES E.
KEPPLER 17 STEUART E.
EBNETER 18 ANDRES DUBOUCHET
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JAMES LEIVO RONALD PARKHILL 19 GENE V.
IMBRO ROBERT E.
SHEWMAKER 20 RICHARD MCFADDEN HAI-BOH WANG 21 DOUGLAS WILSON MICHAEL J.
RAY 22 CHARLES H.
FOX i
STEVEN A.
WHITE 23 CHARLES C.
MASON RICHARD L.
GRIDLEY 24 HERBERT L.
ABERCROMBIE BRIAN K.
GRIMES 25 l
Heritage Reporting Corporation (202) 628-4888
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p R'O C'E'E.D I N G S 2'
~ MR. ZWOLINSKI:
My name is John Zwolinski,'and I am 3
the Assistant Director for Projects in th'e Office of Special
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4 projects.
The purpose of today's meeting is to have Lthe staff 5
present its findings of the results from the integrated design
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6 inspector having been conducted over the past.two months.
We 7-are passing an attendance list about the. room, and we would
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8 appreciate you filling it in as it will be part of the meeting 9
minutes.
This meeting is being transcribed, and that will also 10 be an attachment to our meeting minutes..
11 At this point, I would like to have the members of' 12-the various staff sitting at the' table introduce themselves 13 being perhaps with Mr. Abercrombie.
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14 MR. ABERCROMBIE:
Herbert Abercrombie, site director.
4 15 MR. GRIDLEY:
Dick Gridley, director, nuclear safety 16 and licensing.
J 17 MR. MASON:
Chuck Mason, deputy manager, Office of 18 Nuclear power.
I 19 MR. WHITE:
Steve White, Office of Nuclear power.
20 MR. FOX: ' Charlie Fox, Office of Nuclear power.
21 MR. RAY:
Mike Ray, IDI team leader.
22 MR. WILSON:
Doug Wilson, nuclear engineering.
23 MR. MCFADDEN:
Dick McFadden, electrical engineering 24
' team, inspector leader.
25 MR. HAI-BOI:
Wang'Hai-Boi, civil structure team.
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MR. SHEWMAKER:
Bob Shewmaker, co-IDI team leader..
2 MR. IMBRO:
Gene Imbro, NRC.IDI team leader.
3 MR. PARKHILL:
Ron.Parkhill, mechanical systems lead.
4 MR. DUBOUCHET:
Andy Dubouchet, mechanical components 5
lead.
' instrumentation and control 6
' MR. LEIVO: ' Jim Leivo, i
7 systems lead.
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MR. GRIMES:
Brian Grimes, safety. director, Division 9
of Reactor Inspector and Safeguards.
10 MR. ZWOLINSKI:
John Zwolinski.
11 MR. EBNETER:
Stewart Ebneter, director,_TVA.
12 MR. KEPPLER:
Jim Keppler, director of the Office of 13 Special Projects.
14 MS. AXELRAD:
Jane Axelrad, deputy director of the 15 Office of Special Projects.
16 MR. ZECH:
Gary Zech, assistant director for 17 inspection programs.
18 MR. LIAW:
B. D.
Liaw, assistant director for 19 technical programs.
20 MR. ZWOLINSKI:
Thank you.
As I mentioned, meeting 21 minutes will be issued in approximately a week containing the 22 transcription of this particular meeting.
As this is an exit I
l 23 meeting, there are a few unique aspects which are taking place I
24 today.
Normally when we conduct an inspection, we would 25 document our findings and provide an inspection report very
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quickly.
2 We are here today to present our findings, and these 3
will be documented in an inspection report scheduled for early 4
November.
We are not attempting to resolve questions that may 5
come up today.
However should you have questions regarding any 6
specifics that the team members might be presenting, seek 7
clarification as necessary.
But we are not attempting to 8
resolve issues that rnay arise.
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At this point, I would like to turn the meeting to 10 Jim Meppler.
11 MR. KEPPLER:
Thank you, John.
In the beginning of 12 June, we made the decision that an independent design l
13 inspection was needed for the Sequoyah project before we could 14 conclude that the efforts undertaken by TVA were sufficient 4
15 enough to permit restart of the reactor.
16 We gave TVA the option of conducting that inspection 17 at that time or to do it with an internal inspection of the 18 NRC.
And at the meeting in Washington to discuss this, TVA 19 took the position that they could not commit to an inspection 20 at that time.
So we made the decision to move ahead to conduct t
l 21 this inspection.
l 22 We laid out a schedule in which this would be 23 conducted, and we set at that time the date of September 11th 24 to brief you on.
We have met that schedule, and we are here to 25 share with you the results of that effort today.
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This was a controversial decision which TVA did not 2
feel the need for this inspection.
But I will say publicly 3
that you supported the inspection fully, and we appreciate that l
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. effort.
But we-have put together a strong team to look at the 5
various engineering disciplines associated with one of the 6
safety systems in the plant.
7 Now we recognize in carrying out this effort that we 8
need to get to you for you.
For you to meet your schedules, we 9
need to get to you information by the early part of October of 10
'what work has to be tied to restart of the reactor.
So if you 1
11 have additional information relative to this inspection effort, I
12 which I understand you do have, it is important that you get l
13 that information to.us in a very early time frame.
Because 14 otherwise, we are just going to have to push back our' dates.
15 I am somewhat concerned that information will be 16 coming in late, but I realize that this is a complicated 1
17 inspection effort, and that this will necessitate back and l
18 forth flows of information.
19 But what we are here to do is to share with you our 1
20 view as we have the information today.
We are going to proceed 21 in writing the report that way.
And so if you have.information 22 which significantly affects the findings that we are talking 23 about today, it is incumbent upon you to get that information 24 to us promptly.
25 Gene, I will turn it over to you now, or do you want Heritage Reporting Company (202) 628-4888 l
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to make some remarks?
2 MR. EBNETER:
Just one comment'briefly.
The 3
integrated design process consists of two parts for Sequoyah, 4
as you recognize, and one'of.them was the as built inspection 5
at Sequoyah which we completed, and we held the exit interview 6
at Sequoyah.
There are some common threads running between 7
-these two, as there should be, because the as built should B
reflect the actual incorporation of the design features of the 9
plant.
10 So as you go through this, as Gene goes through his l
11 findings, you will find some common threads in electrical' 12 separations over pressure protection and design engineering and 13 the operations interface.
And both of these areas should be i
14 viewed in that light,'that they are not completely separate, 15 but they are tied to operations and the plant condition as well 16 as Knoxville.
17 That report should be out in about two weeks.
Frank 18 McCoy has the final draft ready now, and you should get that in l
19 about two weeks, and it will identify some deficiencies similar i
20 to this.
21 MR. KEppLER:
What we are going to do is Gene Imbro 22 is going to Dive you some information related' to the conduct' of 23 the inspection.
And I had a briefing yesterday by my staff, 24 and I thought that I would share with you how I view the 25 results, and then turn it over for the detailed results to the Heritage Reporting Company (202) 628-4888
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1 individuals.
2 Do you have any remarks that you would like to make?
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MR. WHITE:
Yes.
I would like to say one thing.
I 4
agree very much that -- of course, the effort, first of all, is 5
kin'd of unprecedented, to do what we both attempted to do here.
6 And I appreciate your words that we have tried to support you l
7 as best we could.
We also very clearly understand I think, 8
first of all, that as the process went on, I think the teams I
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9 worked very closely together, and we were able to furnish 10 information to my understanding fairly rapidly until late in 11 the game where at some point in time and I understand this, 12 that at some point in time your team leader, Mr. Imbro, has to.
13 stop and say wait a minute I have got to now write a report.
14 So at that point in time, which was I guess roughly.
10 last week, about a week ago, I clearly understand why he could i
16 not accept information from that point on or at least limit it, 17 because he had a job to do to get ready for today, _and we 1
l 18 understand that.
But as a result, we do have much information l
19 that we are ready to transmit on a number of these issues very 20 quickly.
l 21 So I appreciate your words.
I think that they are l
22 very appropriate.
I think that after this meeting that we need 23 to keep those teams very closely aligned, so that we can have a i
24 rapid transmission of the information that we have now
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25 accumulated.
And of course, we are out getting other j
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information.as necessary to answer the various issues.
2 MR. IMBRO:
Before I start, I would like to introduce 3
the rest of our team which are not sitting:at the table right 4.
now.
Let me Just go through the first row there.
If,you would 5
all stand up when I introduce you.
Ahmet Unsal.
6 MR. UNSAL:
Ahmet Unsal, specialty.
2 7
MR. MALLEN:
Owen Mallon, structural team.
8 MR. MASTERSON:- Bob-Masterson, mechanical components.
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MR. FERRARINI:
Vic.Ferrarini, mechanical components.
i 10 MR. CHEN:
S. T.
Chen, instrumentation and control.
11 MR. HOUGHTON:
Jim Houghton, mechanical.
1 12 MR. HALLER:
John Haller, electrical.
13 MR. IMBRO:
Thank you.
And I would Just like to take 14 a minute here to thank them all for what I consider.to'be a 15 very professional and thorough Job during the inspection.
It 16 was a very difficult inspection, and as Mr. White said, 17 unprecedented.
18 There are a lot of TVA people here. But for the 19 benefit of those who are not TVA and some of the media people, 20 I just wanted to go through a little bit of what I spoke about 21 in the entrance meeting as to what the purpose of the 22 inspection is and a little bit of how we conduct the 23 inspection.
24 First of all, the primary purpose of the inspection 25 was to get a handle on the adequacy of the original design of Heritage Reporting Company (202) 628-4888'
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the Sequoyah plant.
Now what we tried to do was to review the 2
original design calculations of the documentation and purchase-3 specs.
But since the system we chose has evolved substantially 4
during the years, it became necessary not only to look at the 5
original design but some of the more current calculations.
And l
6 we wound up looking at the system as it. stands today and give 7
comments relative to the adequacy of that system.
8 This inspection is termed the integrated design 9
inspection.
And the reason that it is called that is in the 10 design of a nuclear power plant there needs to be a lot of 11 interdisciplinary communication.
There are a lot of different 12 engineers and different design groups working on the project, 13 and they essentially need to have a coordinated effort to make 14 sure that everything turns out the way that it is supposed to 15 and meets the NRC requirements.
16 So how we structured our inspection is basically we 17 had a team consisting of five major discipline areas.
The 18 first area was mechanical systems.
And that essentially was to 19 look at flow calculations and transfer calculations, and that 20 type of thing which we consider as systems.
21 The second area was a review of mechanical 22 components, and that essentially is piping, pipe supports, and l
23 also seismic qualification of equipment.
l 24 Now structural design was another area that we looked 25 at.
And both of these two areas, mechanical components and Heritage Reporting Company (202) 628-4888
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structural design in TVA basically are embodied in the civil 2
engineering branch.
We also looked at instrumental ion tsnd 3
control, and we looked at the electrical power.
4 Now the types of documents that we reviewed Just 5
quickly.
Obviously, we looked at calculations, and we looked' i
6 at TVA drawings, and we looked at TVA procurement documents, j
7 and we looked at design change documentation, design change; j
8 requests, nonconformances, et cetera.
We also looked at 9
maintenance requests, and licensee event reports, and_TVA s
10 design criteria.
11 The reason that we looked at the maintenance requests 12 and licensee event reports was that we tried to get a sense of 13 how the system was operated and'tried to spot in looking at 14 those anything that we perceived maybe to be design problems 15 thct came about through repeated maintenance on components or 16 an abnormal number of licensee event reports in the same area.
1 17 The standard that we used to judge design adequacy 18 are the licensing commitments that TVA made in their FSAR that l
l 19 were approved by the NRC.
And embodied in those licensing 20 commitments are certain codes and standards which TVA has 21 committed to.
For example, ACI-318, 1963 and ACI-B-31.1, 1967 22 for piping, and there are many, many others.
23 We selected the ERCW as a system for review partially 24 because we felt it was representative of TVA work, design work, 25 during the period of time when Sequoyah was being' designed.
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is a safety related system, and it = is one of the systems that-2 TVA has sole responsibility.for design as opposed to other 3
systems which are. supplied by'the_ reactor manufacturer.
4 The investigation was pretty intensive.
We had a 5
large team by normal inspection standards, and it is_about 6
average for IVI.
And as you can see, we had fourteen team 7
people, team members, and essentially about six weeks of 8
effort, four weeks of direct inspection plus the time back in' 9
the office where we also continued our inspection reviewing 10 documents that we had taken home with us.
So you can see.that j
11 it is a rather intensive and focused effort on one particular f
l 12 system.
13 Before we started this inspection, we anticipated i
14 that there were going to be problems.
And if I could 15 characterize that.
Any time you get a team of experts, as my 16 team is, no matter what plant in the country we go into, we 17 find problems.
It just goes without saying that you are going 18 to find problems.
19 And the problems vary depending on the utility and 20 how they approach the design.
But we knew that we were going i
21 to find things wrong when we went in to look at the design.
22 Some things surprised us and some things we expected.to see.
23 Let me go through quickly what we consider to be the 24 major problem areas.
First of all, we feel that there is major 25 programmatic weakness in structural calculations.
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i structural calculations are those which essentially support the 2
design of the building and support the equipment. foundation and 3
those type of things which are done in the-civil engineering-4 branch.
5 Also.we feel that there is a programmatic weakness in 6
TVA review of seismie qualification reports provided by the 7
vendors and also in equipment seismic qualification.
We also 1
8 feel that there is a programmatic weakness in the design of 1
9 pipe supports.-
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10 Before I go on, to try to set the tone for the 11 meeting, we are going to try to give a ba' lanced presentation.
12 We are also going to try and say what we saw good about TVA and l
13 what we say that we did not think was quite as good.
But'the 14 focus of this meeting for TVA's benefit is essentially to point 15 out to them the areas where we think that they need to do-16 additional work.
l 17 So members of the press, I think that they really' 18 should understand that the reason that they are not hearing a.
19 lot of good thinDs is not because a lot of-good things do not j
20 exist, but we are not really focusing on those right now.
We 21 are really trying to concentrate on areas' where we think that 22 TVA needs to do additional work.
But we will try to go into 23 some of the positive things also.
24 Other-problem areas, to continue.
We found a problem 25 in equipment qualification placed in a mild environment, and Heritage Reporting Company (202) 628-4888
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that is not the11ntent 'of 450-49.
.We al'so=found' inconsistent
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2 apd21 cation.of the code of; record for' piping systems.
.And I' thihk-that presented-some. confusion'in'TVA.-
We also found.
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problems related to the design pressure;of the ERCW system 5
which.was'again our primary system which we looked at.
6 So there were a. number of things that we.foundLthat=
i are indicative cerpsinly. that TVA has got a little. bit.further 7
8 to go to get the, plant' design cleaned up; -And we also have to A
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.ac now e ge. that in the last few years since I~have been' k
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i 10 involved with TVA that I feel that thry really,have come's long j
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li 12 On the positive side, TVA has put togetherJagain as"a
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13 part of tho1 design base line and verification program'a very
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14 comprehensive set of design criteria which from our point of l
1 15 view looking at.the different plants.in the 1'ndustry,:we think 16 that they are quite superior to a lot of things.that1we have j
17 seen.
So I think that the fact that they have-a strong basis
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18 for design now will certainly go a long way to help them.in the 1
19 future in the plant design in accordance with criteria.
y 20 We found that we generated calculations for the most-21 part that were clearly improperly performed.
Also I have to gcc 22 back and say that in our last inspection we did find. problems.
23 with regenerated calculations, particularly those performed by' j
24 contractors, and we still have those problems.
'But thingri that tg' t
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getting better.
E' Electrical calculations.
TVA took the init iative-I 1
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' guess about a year or so ago to' completely redo the. electrical <
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calculations, and we' feel that they~have done a very complete.
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and comprehensive-Job.
The cale design documentsiwe found to 6
be readily retrievable.
-In some plants, that kind of document 7
retrieval is very difficult.
And that essentially made the inspection a litt' e bit easier for' us. 'Andlcertainly, TVA's-l 8
9 cooperation in helping us get the design documents went a long 10 way to help us along also.
j 11 Another thing that I view as positive at least is the.
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12 development of the CCRIS system.
And that'is a system,. I guess 13 that I do not really remember what.the acronym stands forfright L
14 now, but. basically.it is a. system where you can track. inputs
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15 and outputs of calculations-so that.you know exactly what.
16' calculations support other calculations.
So if you make a.
17 change in one, you know that you.have to change all of the-18 others.
That is something else that~I have never seen in the 19 industry, and I think that is a very. good thing to have.
20 So I guess with that sort of1 preamble, I will turn it i
21 back to Mr. Keppler now.
22 MR. KEppLER:
Thank you,. Gene.
.I mentioned yesterday 23.
that I received a briefing that you are going-to receive today 24 from the team members.
I had an opportunity to'ask aflot.of l
25 questions and tried to focus a perspective on each of the Heritage Reporting. Company
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What I' came away withwas the fheling that in the 3-areas of.mechanica1', electrical, mechanical components, and l
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instrumentationJand control that while we have findings in 5-these areas and there were some surprises to us, I would say
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that~on a big picture look-that the plant did not come out'too l
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. bad.
Maybe a little better.and a little worse in, spots than we
'8 would have expected, but not grossly off the mark.
9" The area that shakes-me persona 11yf is the civil 10 structural area.-
Based on the information that we have today,
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we think that the inspection came up very'shortiin that' area in H
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12 terms of the findings.
And it is of some concern to me because J
13 what we went looking for in this inspection was to make sure l
14 that there was no major area overlooked by TVA in its review q
15 programs.
16 At this stage, and I caution the comment that I am 17.
going to make, but at this stage-based ~on the information that' l
18 I had, it is of concern to me that this'can lead to delays in i
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19 the plant.
So if.you have information which changes our view, 20 it i s very ' irnport ant that we receive this information.
We will l
21' keep an open mind on out findings and.we have instructed the-i 22-team to do that.
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23 We recognize from discussions between the'various i
24 organizations that you do have a view that is not similar.to j
25 ours in this area.
But based on the information that I sat i
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with today, I have a concern that this area has the potential 2
to set things back.
3 So this is the area that you ought to focus very E
4 carefully on in the findings.
Not to overlook the other areas, 5
but to make sure that the concerns that we have in this area 6
are properly. addressed.
7 MR. WHITE:
I think that'I understand that, Mr.
8 Keppler.
And of c'..urse, that is the area where I believe we l
9 have the most information available and ready to turn over to 10 you, and I appreciate the fact that you and your team will keep 11 an open mind when you receive this information.
'I think that 12 is the s,rea where the majority of our information is available.
i 13 MR. IMBRO:
Thank you.
Before I turn it over to the 14 teum, maybe just a quick word for some of you people who are 15 not familiar with the Sequoyah design as to what the ERCW is 16 and what it does.
Basically, ERCW is an acronym for essential 17 raw cooling water system.
18 What it does is that it is essentially the primary 19 heat removal system for safety related equipment, and it would 20 reject the plant's heat from that equipment to the river.
So-l 21 essentially, it is a cooling system for heat exchangers 22 interfacing with various other systems and certain components 23 such as air compressors, and seal conversion, and a whole raft 24 of other things.
25 So it is a safety related system that communicates a
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with the river and provides cooling for quite a large number of j
2 essential components.
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I guess that I would like to start going through'the j
4 discipline summaries now.
First, I would like to present Ron 5
'parkhill, who will talk about the mechanical systems area.
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6 MR. pARKHILL:
Myself and Jim Houghton performed a l
7 review of the mechanical systems area.- The mechanical systems 8
discipline for the Sequoyah IDI reviewed the ERCW systems for 9
implementation of licensing commitments.
The scope included a 10 review of the thermal and fluid design basis of the system, the I
11 procurement specifications, compliance with the governing 12 codes, interfaces with other design disciplines.
Hazards 13 analysis including monitored energy line break analysis, 14 flooding, seismic two over one considerations, testing 15 procedures, operating and maintenance interfaces, and various 16 FCRs, NCRs, ECNs, CAGRs, and maintenance requests.
i 17 In the mechanical systems scope of review, the IDI j
18 team noted the following good practices by TVA.
The new and 19 recently revised calculations are generally clear and supported
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20 the stated objective.
Where problems were identified, TVA 21 promptly defined the proposed corrective action.
Design 22 criteria documents are generally up-to-date reflecting the 23 current licensing commitments.
24 An effective ASME Section 11 program is in place.
An 25 effective moderate energy line break analysis has been Heritage Reporting Company (202) 628-4888 t
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performed.
An extensive surveillance program is in place for 2
erosion, corrosion control, and MIC which is microbiological 1y 3
induced corrosion.
4 Additionally, system modifications are in place for 5
long-term resolution of these problems.
However, the Office of 6
Special projects has the responsibility for review regarding 7
the MIC issue.
8 The following problems were identified in the i
9 mechanical systems review.
The first problem is associated j
l 10 with the design pressure of the ERCW system.
TVA's stated I
l 11 design pressure of the ERCW system is 160 psig except for the l
12 piping in the ERCW pump house which is 180 psig.
TVA' s 13 associated design pressure calculation identifies many ERCW 1
14 components with a design pressure of 150 psig or less, and 15 attempts to Justify lowering the system design pressure to 150
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16 psig by using administrative measures to limit the pressure in 17 the pump discharge header and using frictional flow losses in 18 the system.
19 The code in effect for the design of the ERCW system j
20 piping, ANCI-B-31.1, 1967, requires that the design pressure l
21 not be less than the maximum sustained operating pressure 22 within the piping, and shall include allowances for pressure 1
l 23 surges.
I 24 The team be'lieves that the ERCW system's design 25 pressure cannot be established by relying on administrative Heritage Reporting Company (202) 628-4888
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measures such as switching ERCW pumps on and off and/or 2
throttling system valves.
Instead a conservative design 3
pressure needs to be established, and the system needs to be 4
designed and rerated for that design pressure or the leak 5
valves provided.
6 The IDI team noted the two following nonconservative 7
assumptions in the TVA nosign pressure calculation.
First, the 8
river water levels above plant elevation 683 up to and 9
including the maximum design basis flood at elevation 726.8 1
10 feet were not considered.
Secondly, the effect of equipment 11 outages was not considered.
12 Additionally, many of the components in the ERCW 13 system have a design pressure which is at least 10 psi less 14 than the current system design pressure of 160 psig.
TVA needs 15 to reconcile these differences.
16 Finally, the auxiliary air compressor cylinder and 17 after cooler as well as a station air compressor cylinder and 18 air cooler have design pressures less than 75 psig.
Throttling 19 of the upstream valves cannot be relied upon for over-pressure 20 protection.
And either the equipment must be rerated for the 21 maximum sustained operating pressure or relief valves provided 22 as required by the code in effect.
In summary, the system 23 needs to be requalified for the established design pressure or 24 relief valves provided.
25 With regard to safety related and non-safety related Heritage Reporting Company (202) 628-4888
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interfaces, TVA does not have an analysis'which adequately 1
2 evaluates the consequences of failure of the ERCW non-seismic 1
3 piping to the station air compressor coolers.
Such-an analysis j
4 needs to demonstrate that the functionality of the ERCW safety
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5 related equipment is not degraded by the failure of the 6
non-safety related portion of the system that is not 7
seismically designed, j
8 Additionally, TVA has no procedure which ensures 9
consistent identification of location of safety class f
i 10 boundaries.
Three examples were identified by the TVA team i
11 where safety class boundaries were improperly identified, and 12 one such example is provided here.
The TVA Class C piping f
13 interfacing with the AERCW and old AEi.CW intake pumping station 14 has lower TVA Class G components within the Class C system.
15 With regard to qualification of equipment in'a mild 16 environment, two problems were identified.
The first problem 17 is associated with the mild environmental qualification of the 18 AERCW components.
The specifications augmented by contractor 19 data for the AERCW pumps, strainers, screen wash. pumps and 20 traveling screens were compared to the drawings entitled 21 wovironmental data mild.
It was noted that none of these 22 specifications had temperature ranges that were compatible with' 23 the environmental data drawings.
24 The inconsistencies noted raised the concern that 25 other equipment may not be qualified for the mild environment Heritage Reporting Company (202) 628-4888
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in which it has to function.
2 The second problem under this heading is associated 3
with establishing the maximum and minimum temperature limits 4
for the AERCW pump house at elevation 704 feet.
The 5
calculation which established the mild environmental conditions 6
for Sequoyah and Watts Bar was reviewed for the portion that 7
applies to the AERCW pump house..
8 Review of this calculation identified two problems.
l 9
First, the maximum temperature limit was not based on 10 technically justified heat gains and losses, but rather on 11 unjustified assumptions.
Secondly, the lower temperature limit 12 did not assume the worst case failure of non-1-E equipment, 13 namely room heater off and ventilation. fan on.
Also, heat 14 losses through the uninsulated concrete walls were incorrectly 15 neglected.
16 As a result of these concerns, TVA needs to ensure 17 that this entire calculation provides a technically justified 18 basis for establishing the mild environmental temperature 19 limits throughout the rest of the plant.
I 20 In response to the previously mentioned IDI t eam' s 21 concerns, TVA provided a more rigorous analysis of the AERCW 22 pump house mild environment temperature limits.
However, this 23 newer calculation did not adequately establish the lower 24 temperature limit associated with the abnormal condition LOCA 25 due to a number of non-conservative assumptions.
Heritage Reporting Company (202) 628-4888 w
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The.next finding is associated with TVA not having an 2
approved operating procedure for manual operation of the screen 3
wash pumps.
The AERCW screen wash pumps are designed to be 4
operated automatically based on traveling screen high 5
differential pressure.
However, a temporary change removed the
~
6 existing differential pressure automation and recommended 7
. procedural' control utilizing. manual operation of the screen 8
wash pumps.
9 However, no procedure has been' approved for manual-10 operation.
This demonstrates a lack of timely implementation 11 of the formal procedure by operations.
12 With regard to the definition and application of code 13 commi t taent s, TVA has been inconsistent with the safety related 14 ECRW piping components, specification, and in-service testing.
15 For piping design, the TVA has inconsistently used ANCI B-31-1, 16 B-31-7, and ASME Section 3 as the code in effect.
17 For components, the screen wash pumps were procured 18 to manufacturer's standards rather than the FSAR identified 19 code of ASME-3.
For specifications, professional engineering 20 decertification was not obtained for procurement modifications 21 to the original design specs.
For testing, the screen wash 22 pumps were not included in the ASME Section 11 pump 23 in-service test plan even though these pumps were safe;y 24 related TVA Class C per FSAR and performed the safety ralated 25 function during normal plan operation.
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Therefore,,TVA needs to clearly define how the
-l 2
various codes in effect'are applied and document them l
I 3
consistently in the design basis documents.
4 The final mechanical system IDI team problem 5
presented here today is associated with breach.of containment 6
integrity.
-In the design criterion title flood protection 7
provisions,-TVA indicates that'during a design basis flood that
)
~
i l
8 it may become necessary to cut a hole in the free standing 9
steel evntainment to prevent external build-up of water I
i 10 pressure'on the steel containment vessel.
. Cutting a hole.in j
11 the steel containment vessel under the design basis flood has
]
12 not been formally identified to the NRC, and therefore'cannot I
I 13 be reviewed for acceptability.
i 14 A summary for the mechanical systems.
As indicated 15 in my introduction of the mechanical systems IDI team review, 16 the majority of the items reviewed are considered to be 17 adequate.
However, of the items discussed, the following have 18 potentially significant generic impact.
Code compliance in the 19 areas of design pressure and over-pressure protection, 20 assurance that ' failure of non-safety related portions of the 21 system do not functionally degrade the safety related system 22 and assurance that safety class boundaries have been adequately 23 located, qualification of. equipment in a mild environment, and 24 inconsistent application of codes in effect.
25 When we came here to perform this inspection, we Heritage Reporting Company (202) 628-4888 l
24 1
expected to find problems, as Mr. Keppler indicated, much like 2
we would find at other facilities.- However, we did not 3
anticipate the problems associated with design pressure and 4
codes in effect would be identified.
This concludes my 5
remarks.
6 MR. IMBROs. Thanks, Ron.
Next I would~1ike to turn 7
it over to Andy Dubouchet, who will discuss the area of G
mechanical components.
And again this is piping, pipe support, 9
and seismic qualification of equipment.
10 MR. DUBOUCHET:
In the mechanical components 1
11 discipline, the IDI team reviewed a selected sample of the j
12 equipment, piping, and pipe supports installed in the essential 13 raw water ce>1ing system at the Sequoyah Nuclear' plant, Unit 14 2.
For each of these areas, we reviewed TVA's licensing 15 commitments, the industry codes of record which TVA used, and 16 TVA's technical design criterim.
TVA's commitments to the 17 criteria contained in these documents form the basis for our i
18 technical review.
19 Before we summarize the problems identified during 20 our inspection, we would like to emphasize that six weeks were 21 spent inspecting a substantial sample of the equipment, piping, 1
22 and pipe supports in the essential raw water cooling system.at 23 the Sequoyah Nuclear plant.
We found a major portion of the 24 documents that we reviewed to be in accordance with TVA's 25 licensing commitments and design criteria.
Heritage Reporting Company
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The team was impressed with the technical expertise 2
of the TVA engineers with whom we interface.
We were also 3
impressed with the quality of TVA's engineering procedures and l
4 design criteria and the project's ability in general to 5
retrieve important documents in a timely manner, j
6 A number of the problemc that we identified appear to 7
be isolated.
However, we identified two areas of concern that 8
will require TVA review in the areas of equipment l
9 qualification, seismic qualification, and design of pipe 10 supports.
l 11 In the area of equipment seismic qualification, we 12 will review TVA's equipment procurement documents to confirm 13 that these documents incorporated the appropriate technical l
14 criteria and specified appropriate levels of design control.
15 We also reviewed the equipment seismic qualification documents 1
16 which the equipment vendor prepared to confirm that the vendor 17 qualified the equipment to the specified technical and design 18 control criteria.
]
l 19 The deficiencies that the team identified during the l
1 20 course of this review were characterized primarily by vendor j
21 equipment qualification documents that did not meet the
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i 22 requirements of TVA's equipment procurement documents.
23 The following nine examples are provided.
For the 24 first example, the vendor seismic qualification calculation for 25 the motor operated valves that regulate the flow of emergency 1
1 Heritage Reporting Company l
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- - - _ _ - - _a
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1 make-up water to the turbine' driven auxiliary feedwater pumps
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2 uses a design pressure of 50 psig, although the system design 3
pressure is 150 psig.
The vendor seismic qualification report 1
4 combines the valve seismic loads with valve operating loads 5
based on 50 psig to seismically qualify the valve.
l 6
The second example involves the vendor's seismic
]
7 qualification document for the turbine driven auxiliary 8
feedwater pumps which does not address the axial thrust of the J
9 pump discharge nozzle due to the 1650 psig pump discharge) 1 10 pressure as required by TVA's pump procurement document.
This 11 is a concern for the motor driven as well as the turbine driven 1
12-pumps at Sequoyah Nuclear plant, j
13 The third example involves TVA's procurement of 14 flexible hose for safety class application in the essential raw 15 cooling water system.
In this instance, TVA took unjustified 16 exceptions to the criteria within its own procurement document l
17 to reduce the seismic and quality control requirements that the 18 flex hose vendor was required to. satisfy.
19 The fourth example involves the vendor seismic 20 qualification document for the upper containment air cooler.
21 The calculation contains an error which when corrected yields a j
22 unconservative minimum freque,1cy for this equipment.
This 23 document was apparently not designed verified by the vendor or 24 by TVA as required by the PSAR and TVA's procurement document 25 for the equipment.
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O 1
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The fifth example involves separate se'ismic 2
qualification reports for shut-down board room chiller B and 1
3 its associated control box which is mounted on the chiller 4
unit.
The seismic reports violated a key technical provision-
~
5 of the equipment procurement document which requires that no 6
device location on the support structure be permitted to have 7
an acceleration greater than three-quarters of.the actual 8
device test acceleration.
9 The sixth example is similar to the fifth_and 10 involves two Westinghouse reports which separately qualify a l
11 Westinghouse vertical auxiliary panel and two. types ~ of 12 Westinghouse switches.
These documents did not meet the same 13 key provision of TVA's procurement document for this equipment l
14 which requires that the switches on the panel be limited to 15 seismic acceleration less than three quarters of the actual.
16 switch test accelerations.
This provision is also a FSAR j
17 requirement for panel supporting electrical and control 18 devices.
19 The seventh example documents the team's concerts with 20 the design changen that permit the field to procure and install 21 electrical and control devices such as relays, timers, and 22 terminal blocks, and previously qualified-Class 1-E panels I
23 without an apparent engineering review.
This review was required to confirm that the original seismic qu$lifications of 24 l
25 the panels and devices remain valid.
l Heritage Reporting Company (202) 628-4888
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28.
i i
For the eighth example, the equipment vendor's 2
calculation for the component cooling water and containment-3 spray heat exchanges were not' performed in accordance with 4
technical requirements.specified in TVA's procurement document.
5 The vendor's calculations appear to be unconservative' with 6
respect to TVA's requirements due to the fact that two nozzle 7
. shift forces were not considered for both the equipment and 8
their supports.
i 9
In addition, TVA did not install the component
- l 10 cooling water heat exchanger in accordance with the vendor's 11 drawing.
TVA installed the heat exchanger.usinD three supports 12 rather than two supports as shown on the vendor's drawing.
No l
13 calculations were performed by TVA or the vendor to evaluate 14 the effects of this additional support on' the heat exchanger 15 shelf.
16 The last example concerns TVA's ' inability to 17 demonstrate or TVA design verified the vendor's seismic j
18 qualification reports for the upper containment air cooler, 19 lower containment air cooler, and the control ~ rod drive air l-20 cooler.
Design review and certification of vendor seismic 21 qualification documents was a pSAR and TVA procurement document 22 requirement.
23 The team notes that failure to perform a design l-24 review may result in incorrect'or unverified assumptions or 25 calculation errors which may affect the seismic qualification Heritage Reporting-Company 1
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29 1
of the equipment.
This item therefore has generic implications 2
for equipment requiring seismic qualification.
j 3
In the area of piping analysis, the team reviewed a j
i 1
4 number of safety class piping subsystems within the essential j
i 5
raw cooling water system that TVA either computer analyzed or j
E field routed.
The team documented several deficiencies in this j
i 7
area due primarily to inconsistent documentation, calculation 8
errors and omissions, and failure to meet FSAR commitments.
l l
9 The following four examples are provided.
In the 10 first example, TVA did not analyze a piping subsystem for a l
I 11 thermal load which is specified in the FSAR.
TVA did not 12 analyze the piping between header 2-B and containment spray l
i 13 heat exchanger 2-B for the cold thermal mode or the thermal j
i 14 range.
l 15 A second example concerns TVA's failure to model the 16 flexibility of a valve operator in a piping analysis i
17 calculation as required by the FSAR.
The FSAR requirements j
i 18 that valve operators with fundamental frequencies less than 25 l
l l
l 19 hertz be modeled in the piping analysis as flexible.
{
20 The third example concerns TVA's inability to confirm I
21 that temporary piping can be installed in the essential raw l
l 22 cooling water system including the spool piece which connects l
l 23 header 2-B to the component cooling water surge tank without 24 overloading the adjacent piping and supports.
TVA may have j
25 fabricated some of the spool pieces to nominal rather than to l
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as built' dimensions.
2 As'a fourth example, the team noted that in a portion' 3
of the piping analysis that TVA elected to reduce the seismic 4
stress at a T connection by incorrectly interpreting and 5
improperly applying a provision of the piping code of record l
i 6
for the Sequoyah Nuclear plant.
7 TVA performs pipe stress analysis using the ASME 8
.Section 3, Subsection NC-3600 stress equations.
The piping 9
code of record for Sequoyah is ANCI-B-31-1, 1967 edition.
]
10 has Justified using the NC-3600 equations because they are 11 essentially the same as'the B-31-1 requirements.
12 However, for a piping subsystem which used the 13 NC-3600 stress equations and was of a stress at a T connection, j
14 TVA Justified the over-stress condition by using an i
15 interpretation of the B-31-1 code which allowed TVA to ignore 16 the stress intensification factor of the T when computing the i
17 seismic stresses.
18 The team disagrees with TVA's interpretation of the 19 B-31-1 code requirements.
We also take strong exception to.the 20 practice of invoking an isolated portion of'a code to reduce an 21 over-stress condition in order to meet allowable code stress 22 levels.
23 In the area of pipe supports, the team reviewed the 24 pipe support designs and calculations for a number of the pipe 25 supports installed in the essential raw cooling water system.
Heritage Reporting Company (202)-628-4888
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We first note that TVA cannot currently retrieve the 2
calculations for a number of safety class supports at the 3
Sequoyah Nuclear plant.
However, the NRC is separately 4
overviewing TVA's program to regenerate these calculations and 5
the team has confirmed that that TVA has scheduled the missing 6
pipe support calculations which the team identified for l
7 regeneration.
8 For the pipe support calculations that we were able 9
to review, we identified several deficiencies which involved 10 calculation errors and omissions and failure to meet FSAR i
l 11 criteria.
Five examples are provided here.
12 In the first example, TVA used unconservative and 13 incorrect assumptions to analyze three pipe supports in two of i
14 the piping subsystems that the team reviewed.
These errors may
)
15 affect both the structural analysis of the support and the 16 anchor bolt qualification due to the support design.
17 Since the team discovered errors in three of the 18 eight pipe support calculations reviewed, and this was Just in l
l 1
l 19 ene package'as we reviewed many more than eight, the team 20 concludes that generic concerns exist with respect to pipe 21 support calculation adequacy.
22 It should be noted, however, that all three 23 calculations are included in TVA's commitment to regenerate 24 pipe supporticalculations.
25 In the second example, TVA has a FSAR commitment to Heritage Reporting Company l
(202) 628-4888 1
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maintain pipe support stresses below a certain percentage of 2
the specified materia 1' strength of structural steel.
- However, 3
the team noted that TVA's use of allowable load factors for the
'l 4
full load condition can result in pipe support stress levels l
5 which exceed the FSAR maximum allowable stress level.
.]
6 As a third example, the base' plates and anchor bolts I
7 used to attach a pipe' support to a concrete wall or slab for 8
some typical TVA pipe support designs were not sized with l
9 respect to all of.the applied loads.
1 10 As a fourth example, TVA developed: load _ ratings for il pipe clamps based upon testing in accordance with the load l
12 rating rules of AMSE Section 3, Subsection NF.-
However,'the l
13 TVA calculation which evaluated the clamp test data contains 14 several errors and omissions.
For example,lthe calculation did 15 not apply a ten percent reduction in the resulting load rating 16 as required by ASME-3, Subsection NF when only one sample is 17 tested.
J 1
18 Also, ASTM-A-307 boltinD material is used in a.
19 pre-loaded friction connection to resist pipe axial load.
20 However, both AISC and ASME-3, Subsection NF prohibits the use 21 of A-307 bolts in a friction connection due to its uncertain 22 pre-load capacity.
23 Item 5 is related to the previous item and addresses 24 calculations ~ required to augment corrective action for a 25 nonconformance report.
The team reviewed a preoperating Heritage Reporting Company.
(202) 628-4888 i
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license nonconformance report and found that TVA's correct ive 2
action to address the nonconforming condition resulted in the 3
incorrect qualification of previously used pipe clamps for 4
TVA's fuel routed piping program.
5 The corrective action attempted to address the 6
interaction effects of multi-directional loading on pipe clamps 7
which had been previously evaluated for one directional 8
loading.
In the evaluation for the corrective action, TVA 9
failed to properly address the effects of interaction of i
10 tension and bending on the pipe clamp for all clamp sizes 11 required, and unconservatively interacted sheer and tension for 12 the three loading directions on the clamp bolts.
13 To put our findings into perspective once again, we 14 know that we reviewed a significant portion of the equipment, 15 piping, and pipe supports in the essential raw cooling water 16 system with respect to a total of 22 separate inspection l
17 checks.
However, a review for the majority of these checks 18 confirmed with some localized exceptions the adequacy of the 1
19 documentation which we reviewed.
20 However, we reiterate that two areas may be areas of 21 potential generic concern at the Sequoyah Nuclear plant.
The 22 first area is vendor seismic qualification reports which were 1
23 not prepared in accordance with the requirements of TVA's 24 equipment procurement documents and were apparently accepted by 25 TVA without design review.
l Heritage Reporting Company (202) 628-4888
I 34 i
l 1
The second area is pipe support calculations which 2
were not prepared in accordance with TVA's commitments and j
3 design criteria.
4 This concludes the summary of our review of the 5
mechanical components discipline.
6 MR. EBNETER:
Stu Ebneter.
Just one comment.
You.
l l
7 have heard several' comments early on in this discussion about 8
the procurement interface.
And Mr. Karzanis, I see you sitting 9
over there.
I would like to' direct your attention to this.
We 10 repeatedly have discussed it.
There apparently is some 11 difficulty between the design and the procurement interface.
s 12 And we recognize that the total procurement function is not 13 under nuclear operations.
And do not lose sight of the fact 14 that we are talking about design here primarily, but that 15 procurement interface is important.
i 1
16 MR. IMBRD:
Thank you.
I would'like to next turn the j
i 17 floor over to James Leivo, whose discipline is in 18 instrumentation and control review area.
19 MR. LEIVDs Dr. Chen and I conducted the 20 instrumentation and control systems review.
In the 21 instrumentation and controls discipline, the team reviewed 22 several major areas of the design with emphasis.on compliance i
l 23 with FSAR and other TVA commitments and requirements.as well as 24 assurance that the systems and equipment would function as l
25 required under design basis conditions.
l l
l l
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Where problems were reported within the ERCW system, f
a 2
the team identified any design issues that might extend beyond 3
the ERCW system scope, and we will mention these potential i
l 4
generic issues in this discussion.
5 The major areas reviewed which will be discussed 4
6 included process instrumentation and control detail design, j
i il 5
7 design features provided for a safe shutdown from outside the l
l 8
control room, environmental and seismic design and l
9 qualification, and radiation monitoring.
10 The selective documentation reviewed and discussed 11 with TVA included FSAR and regulatory requirements, standards, i
12 TVA design criteria, engineering procedures, logic and j
l 13 schematic diagrams, instrument installation details, instrument l
14 specification and procurement documents, demonstrated accuracy I
i 15 calculations, engineering change notices, work packages, l
16 nonconformance reports, and various technical documents.
l 17 We will selectively highlight today and report 1
18 comprehensively later the problems and unresolved issues that 19 we have identified during this review.
20 In the first review area, that of design detail, the 1
21 team identified a deficiency in the implementation of the 1
22 mechanical systems functional requirem9nts.
The team observed l
l 23 that TVA did not provide a calculation Justifying the use of 24 manual operator action initiated by a high flow alarm to 25 manually isolate a break in the non-seismic portion of the ERCW 1
l Heritage Reporting Company l
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piping.
l 2
Furthermore, we determined that the enunciator system l
3 is not seismically qualified.
And that in any case, a seismic l
'4 event would likely result in numerous alarms and indications I
i 5
competing for the operator's attention.
The team concludes 6
that timely and sufficient operator action to manually isolate 7
the postulated break has not been assured.
8 Also in the area of design detail, the team l
1 9
identified problems and unresolved issues regarding circuit 10 separation and isolation.
And we will summarize three of the 11 more significant ones.
12 First, the team determined that fuses used to provide 13 isolation of the non-Class 1-E traveling screen feed switch had 14 not been properly coordinated with the control circuit fuse.
15 Since the control circuit fuse is shared by both the Class 1-E 16 traveling screen control devices and the non-1-E feed switch, a i
17 seismic event shorting the switches could render all four 1
18 traveling screens inoperable.
19 TVA should assure adequate fuse or other protective 20 device coordination for all instrumentation and control i
I 21 circuits where credit is taken for fuses as isolation devices.
22 A second item regarding adequate separation of 23 non-Class 1-E from' Class 1-E switch gear control wiring remains i
l 24 unresolved until & satisfactory analysis is provided by-TVA 25 demonstrating that no credible fault is non-Class 1-E wiring Heritage Reporting Company (202) 628-4888
37 1
could be propagated into the Class 1-E wiring where that 2
internal wiring is bundled together.
l 3
A review of the control wiring within the 6900 volt 4
switch gear indiceted that input and output wiring for control 5
relays that are used for isolation devices were bundled l
6 together within the switch gear enclosure such that 7
non-Class 1-E wiring is in contact with Class 1-E wiring.
8 A third item regarding the TVA criteria for 1
1 9
separation of instrument sensing lines and instrument air lines 10 remair.s unresolved in that the criteria permits the use of l
l 11 common instrument line penetrations for redundant channels.
)
1 12 TVA must identify any safety related instrument lines which l
13 share common penetrations and demonstrate compliance with 14 single failure criteria.
l 15 In the second major design area, safe shutdown l
16 capability from outside of the control room, the team 17 identified a deficiency in the circuit design for the traveling 18 screen drives and screen back-wash pumps.
Control indicating l
19 lights for these circuits are directly connected to the control l
20 circuits such that a design basis control room fire could 1
21 render all of the screen wash pumps and traveling screen drives l
l 22 inoperable from many locations.
TVA should examine any similar i
23 indicating light circuits in the control room for this l
l 24 deficiency.
l 25 In the area of environmental and seismic design, the Heritage Reporting Company (202) 628-4888
38 1
team identified two deficiencies.
First,-as noted earlier by 2
-the mechanical systems IDI discipline, the team observed that 3
no analysis had been performed'by'TVA adequately Justifying the 4
absence of qualified environmental control features,in the ERCW 5
pumping station.-
No heat tracing or qualified space' heaters 6
are provided'to prevent freezing of safety.related instrument 7
sensing lines within the ERCW structure.
TVA should also B
review other safety related instrumentation and its 9
environmental protection where extreme temperature conditions 10
.may be. encountered.
11 Second, with assistance from the IDI. mechanical l
12 components discipline, the-team reviewed seismic qualification 13 of the main control board room switch modules.
The efficiency 14 in this area was earlier reported by the IDI mechanical l
15 components discipline.
16 TVA'could not retrieve the calculation demonstrating 17 that the maximum accelerations at all switch locations 18 satisfied the FSAR criteria that the acceleration at the panel 19 mounting location be less than three-fourths of the actual 20 device test acceleration.
Thic FSAR requirement was not 21 evident in the procurement documentation-nor was compliance-22 with the criteria clearly demonstrated by test or analysis.
23 This finding is applicable to all of the main control room-24 panels.
25 Also as previously reported by the IDI mechanical l
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components discipline, an additional unresolved item was 2
identified regarding assurance that instrumentation and control i
l 3
devices identified as field located on drawings are mounted in
)
J 4
locations that do not compromise seismic design and i
5 qualification criteria.
l 6
Finally in the radiation monitoring area, the team i
7 reviewed the specifications and location of the ERCW discharge j
8 liquid monitor and determined that the monitor background
\\
l 9
radiation had been incorrectly specified, since it did not take 10 into account post-accident radiation sources.
I 11 The team determined that the existing monitors will l
l 12 probably not function during a deuign basis accident, since 13 accident background levels were actually at the monitor and 14 will likely mask any measured level.
The FSAR states that 1
15 these monitors are required during an accident to detect 16 leakage of the containment spray or component cooling water 17 heat exchangers into the ERCW system.
TVA should review all 18 post-accident radiation monitors for this type of deficiency.
19 To summarize our review in the I&C discipline, while 20 the team believes that with one exception that the number and 21 significance of deficiencies identified seems comparably low, 22 we would also note that the ERCW system has comparatively l
23 simple and straightforward safety related instrumentation l
24 requirements, and that the electrical and instrumentation 25 discipline has had prior extensive review.
Heritage Reporting Company (202) 628-4888
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The deficiency that seems to be an exception to our
)
i
.I 2
normal expectations for this type of review.is the discrepancy i
3 that we identified in the main control board switch module 4
seismic qualification.
5 This concludes the instrumentation and control j
6 systems discipline summary.
7 MR. IMBRO:
Thanks, Jim.
While at this point rather 8-than continuing, as I know these things get kind of dry and 9
drawn out maybe, I think that it may be appropriate to take a 10 fifteen minute break here to refresh ourselves.
11 (Whereupon, a recess was taken.)
12 MR. IMBRO:
I would now like to turn the floor over 13 to Dick McFadden, a leader in the electrical power area.
14 MR. MC FADDEN:
Thank you, Gene.
15 The electrical engineering inspection team evaluated l
16 the design of the electric power subsystem of the Sequoyah ERC 17 EE system and the electrical supply systems which. support it 18 with respect to conformance to licensing commitments, internal l
19 TVA design criteria and good engineering practice.
l 20 Since the ERC EE power supply is an integral part of 21 the plant auxiliary power system, this inspection developed 22 into a broad evaluation of Sequoyah plant electric power system 23 design.
24 The team examined the following systems, subsystems 25 and components: 6900 volt and 480 volt AC auxiliary power Heritage Reporting Company (282) 628-4888
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1 systems, 125 volt-DC and 120 volt AC vital power systems, l.
2 stand-by diesel generators, motors driving the various ERC;EEE l
3 pumps and' motor. operated valves, ERC EE pump and motor. operated'
~
hi 4
valve controllers,. awitch gear,; including protected relays and-5 circuit breaker trip units, and power conductors.-
6 The teams: evaluation 'of the application and.
j
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1 7
operability of electric power. equipment'and. systems' included-8 tuch critical design issues as the following:. voltage traps 9
under. load, adequacy of emergency power sources to supply'the-l 10 applied loads, capability of. circuit breakers to interrupt 11 available short circuit currents, adequacy and coordination of 12 short circuit and overload protection, system grounding and
]
13 ground fault detection, automatic load transfer from' normal.to 14 alternate power sources. Separation between Class 1E power 15 divisions and isolation from 1E from non'1E power circuits and 1
16 environmental qualification ERC EE-electrical equipment.
l 17 In addition, we evaluated such-design control issues 18 as the execution of engineering change orders, resolution of 19 non-conformance reports and interfacing among the various 20 organizations involved in the design process, TVA design 21 engineering and construction branches, Sequoyah plant 22 operations and maintenance,' vendors, et cetera.-
23 The major deficiency the electrical team identified.
I 24 is the lack of ground fault detection on the entirely
'I ungrounded low voltage, and that 15.480 volts and below,.AC' 25 l
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power systems.
As a result, a line to ground fault can persist 1
2 undetected indefinitely. This condition is unacceptable for two
]
1 3
reasons.
First, a permanent ground fault imposes a continuous I
4 173 percent line to ground overvoltage on the unfaulted phases, 5
which tends to accelerate the deterioration of the insulation 6
of conductors and equipment.
1 7
MR. MC CORKLE:
MEMA standard EEOC 5 1974 to which i
8 TVA is committed in the FSAR recognizes this fact by declaring' 9
that the cable used in ungrounded power systems must have an 10 insulation rating of 173 percent of the nominal system voltage 11 unless the system is equipped with a ground fault detection i
l 12 feature allowing ground faults to be sensed and interrupted l
l 13 within one hour of their occurrence.
14 Much if not all of the cable in the ungrounded 480 1
j 15 volt AC systems at Sequoyah is rated for voltages lower than l
l 16 the 830 volts required by this standard.
Therefore, complying l
l 17 with the FSAR commitment requires either ground fault detection 1
18 or extensive cable replacement.
l 19 Second, the lack of ground fault sensing is a 20 technical violation of the FSAR commitment to the single 21 failure criterion in IEEE Standard 279 and NRC regulatory guide 22 1.53, in that a single detectable failure, combined with an 23 undetected ground fault can result in the loss of both trains 24 of safe shutdown equipment.
25 Furthermore, while there are no explicit regulatory Heritage Reporting Company (202) 628-4888
43 1
rules or TVA commitments requiring auxiliary power. systems to 2
be grounded, ungrounded equipment'-- ungrounded systems are t
3 susceptible to transient over-voltages which are severe enough 4
to damage equipment and conductor insulation, generated by 5
intermittent line to ground faults.
6 To avoid the resulting degradation of power 7
availability accepted elcetric power distribution design 8
handbooks uniformly recommend some form of systems grounding.
l 9
In the team's opinion, installation of ground fault sensing 10 equipment at each safety-related 480-volt distribution 11 substantiation is a minimum requirement.
We further strongly 12 recommend that the ground fault detector circuits be designed i
13 to provide effective high resistance cystem grounding in order 14 to reduce the risk of failures caused by transient over-j 15 voltages.
16 The electrical team's other areas of concern are 1
l l
17 unresolved design issues, rather than design deficiencies.
The 1
18 major questions are the followings first, TV4 has not yet 19 satisfactorily demonstrated that the worse cases were l
l 20 considered in the analysis of auxiliary power system voltage 21 and loading. Additional calculations are needed to confirm that 22 offsite grid power rather than onsite diesel generator power 23 gives the worse voltage conditions, and to establish the effect 24 of unit i loads on unit 2 voltages, when unit 1 is restarted.
1 25 Second, TVA's calculation of control voltages l
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1 delivered to the 6900 volt and 480 volt safety related switch 2
gear and celluloid operated valves under accident conditions 3
are based on the assumption of 120 volts at the vital battery 4
switch boards.
l 5
Various references in FSAR Chapter 8 indicate that 6
the battery voltage can degrade to 105 volts under worst case 7
conditions.
So, a calculation is needed to confirm that the l
l 8
voltage of the loads will still be adequate in this case.
9 Third, TVA has adopted IEEE Standard 382 1974 as its l
i i
10 basis for environmental qualification of electrical equipment.
)
1 l
l 11 More information is needed on the qualification testing of the j
l l
l 12 motors on the limit torque operators for the ERC EE system l
l 13 motor operated valves to confirm that low level vibration, 14 seismic and degraded voltage operation criteria in this l
15 standard have been satisfied.
I l
16 Finally, the team is concerned about the operability j
l 1
17 of some motor operated valves at the low terminal voltages I
l 18 potentially prevailing during an accident.
While most of the 1
19 valve motors were purchased under specifications calling for 20 operability at 80 percent of rated voltage, some others had no 21 degraded voltage specification.
Calculations or tests are 22 needed to confirm that these latter motors are acceptable.
23 In summary, the electric power inspection team found 24 the technical and management aspects of those portions of those 25 portions of the electrical design work which we reviewed to be l
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acceptable with o",1v one significant exception, which is the 2
lack of ground faoit detection on ungrounded low voltage power i
3 systems.
3 4
In~ addition, we discovered a number of open issues 5
whose final resolution will require TVA to provide us with some 6
additional information.
7 We were generally impressed with TVA's aggressive l
l 8
efforts to recover from the deficiencies.in electrical l
9 engineering identified during previous NRC and internal 10 evaluations, which have resulted in a set of electrical design 11 calculations of exceptional comprehensiveness and depth.
12 Now, that concludes the electrical engineering 13 presentation.
14 MR. IMBRO:
Thanks, Dick.
I 15 Next, I would like to turn the floor over to Dr.
l l
16 Hai-Bob Wang, who is the discipline leader in the structural-17 design area.
18 DR. WANG:
Thank you, Gene.
Mr. Ahmet Unsal and Mr.
l 1
19 Owen Mallen and me formed the idea of a structural, civil 20 structural team.
During the inspection we reviewed the i
21 licensing commitment as stated in the FSAR design criteria, 22 engineering, and QA procedures as well as appropriate NRC 1
23 regulations.
We also reviewed a portion of the following 24 analysis and design packages:
The first one was seismic 25 analysis that generates floor response spectra, including the Heritage Reporting Company.
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auxiliary building, the ERCW pump house, steel containment l
1 2
vessel, the shield building and the containment internal i
j 3
concrete structures.
We also reviewed the reinforced concrete I
4 and structural steel design of the auxiliary building and the j
j 5
ERCW pump house.
)
l 6
We reviewed the equipment support, the pipe support, i
7 cable tray and the cable tray support, HVAC dock and the 1
8 support. We reviewed the berry piping analysis, seismic
]
9 analysis of pipe tunnel, ERCW access cells and dikes, seismic 1
10 analysis of steel tags.
i l
j 11 The concerns I am going to present are all negative.
l 12 Most of them are major issues and considered to be generic.
l 13 The first concern is about the seismic analysis.
This 14 generates floor response spectra.
The team reviewed five I
15 seismic analysis calculations and found four of them are not 16 totally checked.
Those partially checked calculations are the 17 analysis of the reactor and auxiliary buildings.
Floor 18 response spectra are used to design equipment and systems that 19 are supported by the floor, such as tanks, pumps, heat i
20 exchangers, pipe and pipe support, cable tray and cable tray 1
21 support, et cetera.
22 TVA did find inconsistency of the vertical response 23 spectra for the steel containment vessel in the winter of 1985.
24 Consequently, a new set of vertical response spectra for the 25 steel containment vessel were regenerated earlier this year. At Heritage Reporting Company
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higher elevations, the newly generated response spectra shows 2
significant increase in vertical observations.
In some cases, I
3 it was several times higher than what was used in the original 4
plant design.
y I
5 TVA is presently assessing the impact of this set of 6
newly generated spectra.
7 The team also reviewed the missile protection 8
analysis of the ERCW pump house roof.
The design of the ERCW 9
pump house roof consists of structural steel members which are 10 rotated 45 degree to provide for missile protection.
The 11 analysis of the roof system conceded only the tactility 12 facto,s.
It did not show that the system would remain stable.
13 The calculation did not evaluate the sheer with -- or f}ange 14 buckling.
It also did not include the potential penetration of l
15 small missiles as committed to in FSAR.
16 The team reviewad equipment support calculations end 17 we have the following four concerns.
The first concern is the 1
18 discrepancies between design calculations and construction 19 drawings.
For example, the component cooling heat exchangers I
20 hood design requires a 3/4 inch thick imbedded plate.
- However, 21 the associate TVA drawing shows only 1/2 inch plate is 22 necessary.
23 The containment spray heat exchanger support has a l
24 similar discrepancy in the thickness of the embedment plate.
l 25 The calculation requires a 3/4 inch and the drawing only shows l
l l
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1 1/2 inch.
I 2
The calculation for the component cooling surging 3
tanks support required 9 anchor stubs with 3 inch spacing 4
between them.
The TVA drawing shows only 8 anchor stubs with l
il 5
spacing varying from 2 to 4 inches.
]
6 Design calculations for the containment spray heat 7
exchangers support how that 5/8 inch diameter and 6 3/8 inch 8
long anchors are required, but the TVA drawing shows only 1/2
]
1 9
inch diameter and 5 3/16 inch long anchors are required.
10 Further TVA review in this area is warranted.
11 The second concern is the possible underestimating i
l l
12 the seismic load on tank support. Seismic calculation for the l
13 mineral rights water tanks used equations from TID 724 to 1
14 determine the dynamic load on the tank and its support.
15 Similar approach was used for this component cooling surging 16 tank calculation. TID 724 as well as other TVA design eriteria 17 for tanks require that the tank be rigid.
However, TVA 18 specifications for tanks require that the tank vendor should 19 develop a lump mass dynamic rcodel of the tank to calculate the 20 natural frequency in order to determine that the tank is rigid.
21 For the mineral rights water tank, the vendor 22 calculation cannot be located and the TVA calculation did not l
23 address the flexibility of the tank.
24 For the component cooling water surging tank, the l
25 vendor calculation did not concede the shield flexibility of l
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the tank.
TVA needs to determine the validity of the 2
assumption that the tanks are rigid.
3 The third concern is that seismic overturn movements 4
are not conceded in equipment support design.
The auxiliary 5
building roof, steel design calculations show that there are 6
four tank supports on girders. These tanks weigh from probably 7
from 90 to 130 kips.
The design of the roof girder and truss 8
did not considor overturn moment from those tanks during 1
9 seismic events.
TVA needs to evaluate the structural adequacy 10 of those supporting girders, including seismic overturn 11 moments.
.12 The fourth concern is that seismic sheer was not 13 considered in equipment support design.
The component cooling 14 water surging tanks support calculations show that tht' anchor 15 bolts were designed for tension only.
The design failed to i
16 consider the fact of sheer as required by the ACI code.
TVA 17 omission of this item may yield an over stress of anchor bolts 18 during seismic events.
19 The team has four concerns with the Peinforced l
20 concrete design which are all related to the auxiliary l
l 21 building.
The first one, the base slab of the auxiliary j
22 building is anchored to rock to minimize the bending stress due l
23 to hydrostatic uplift pressure.
24 TVA calculations show that the net ups pressure was l
25 calculated wrong, since the calculation deducts the total Heritage Reporting Company (202) 628-4888 i
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c 1
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building weight as opposing hydrostatic pressure.
- Instead, 2
only the weight of the base and field slab should have been 3
subtracted.
Also, the number 11 reinforcing' bars used to 4
anchor the slab into the rock did not have enough embedment in i
5 the lens to develop the full strength of the bar.
6 The team believes that the detail of anchorage used 7
by TVA does not agree with the ACI 318-63 code requirement.
8 TVA needs to evaluate the st-uctural adequacy of the base slab 9
taking account of those two deficiencies.
10 The second concern, the team reviewed the calculation 11 for the base slab and the walls poured against rock showed that l
12 no reinforcement was provided at the face of the rock.
The i
13 team is concerned that no consideration was given to determine 14 the effect of cracks that would be introduced by the negative l
15 movement due to the lack of this reinforcement.
i 16 The third concern, the review of the reinforced 17 concrete walls calculations show that TVA provided a minimum 18 reinforcement area of.2 percent rather than the.25 percent 19 required of ACI 318-63.
TVA has not provided a Justification 20 for the use of this lower amount of reinforcing steel.
21 TVA calculations also show that no error -- an error 22 was made in calculating the steel area required in walls.
TVA 23 should evaluate the impact of these two items on the structural 24 adequacy of the walls.
25 The fourth concern, the team reviewed the auxiliary il Heritage Reporting Company (202) 628-4888 l
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building roof slab at elevation 778 and-A15 column lined walls.
j 2
Both,the. roof slabs and the walls are designed in accordance 3
with ACI 318-63 building code as committed in the FSAR.
4 However, this calculation show that TVA' failed to evaluate the 5
sheer stress at edge of the structural elements as required by l
6 the.ACI 318-63 code sections 1201 and 1207.
7 The team is concerned about the lack of evaluation 8
for sheer stress ~due to the brittle nature of failure in 1
9 reinforced concrete structures.
10 The seismic analysis of the ERCW pump house access 11 cells was based on the assumption that the six cells and the i
12 interconnecting cells would act as a one single J-shaped unit.
]
1 13 The calculations show that shrinkage would occur in the 14 concrete field.
The concrete field will therefore not be in l
15 contact with the steel sheet pile.
The calculation also shows 16 that there will be vertical movement between the cells.
The 17 inability of the cel17 to transfer. vertical sheer makes 18 original assumption of the single J-shaped units invalid.
Even 19 if the J-shaped unit assumption is' valid, then the torsional 20 effect of the J-shaped unit should have been considered in.the 21 analysis.
22 The calculation also states that the' cells probably 23 are not-stable if they act as single units.
Failure or 24 excessive movement of those cells would cause the failure of 25 the.ERCW piping and electrical counters embedded in those-u Heritage Reporting Company (282) 628-4888-
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cells.
Therefore, TVA has not substantia 11y' demonstrated that-2 the-cells will be stable under all loading' conditions.-
3 Immediately west of the access cells the_ERCW pip'ing I
4
.and electrical counters are support of a pile support structure 5
embedded in a rock-filled dike.
The response of the pi'.es will J
6 be the same as the rock-filled dike.
The calculations show 7
that the rock-filled dike will not be stable using the material 8
properties stated in the FSAR.
9 Also, the, vertical earthquake was.not considered in 10 the rock-filled dike analysis.
11 Two laboratory tests were_ performed on the rock-12 filled dike material.
The result of the tests indicate that 13 the material of the dike is more stable than the property' 1
14 listed in FSAR.
The original calculation did not incorporate 15 the test result.
Therefore, TVA has not adequately 16 demonstrated that the rock-filled dike is stable.
17 The last concern the team has was with respect to 18 pipe support.
We understand TVA is presently reanalyzing 5000 19 pipe support.
Their accepting criteria state that for the 1
20 self-growing expansion anchor bolts, the factor of safety will 21 be five for long-term operation and the factor of safety of 2.8 22 for the short term or race start.
1 23 The team reviewed pipe support packages and three of 24' them called for RAWL expansion anchors.
However, the 25 calculations revealed do not address _the low ultimate strengths Heritage Reporting Company (262) 628-4888
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of the RAWL expansion anchor bolts which is lower than what was 2
used to determine the acceptance criteri& in the allowable f
3 bolts load.
4 The analysis also increased the allowable bolt load i
5 by taking account of the increase to concrete strengths due to l
6 aging.
This is not a valid assumption since the self-drilling 7
expansion bolts were qualified in higher strength concrete.
8 TVA should identify where the RAWL expansion anchor are used 9
and qualify them in according with the actual ultimate 10 strengths of the bolts.
This completes my presentation.
l 11 i
l 12 MR. IMBRO:
Thanks, Hai-Boh.
l l
13 I would like to take a minute to summarize the 1
14 structural area.
We feel that it is our area of major concern.
15 Just in summary, we in NRC, the RDI team feels that there are a 16 lot of fundamental omissions in civil engineering calculations.
17 For example, there are a lot of unsubstantiated assumptions in 18 calculations.
I don' t know if this is one that Hai-Bob l
19 mentioned before, but one is the analysis of the roof of the 1
20 aux building.
You have an 80 foot steel span and it was 21 assumed to be rigid.
And, again, without obviously, at least 22 to our minds, it is not a rigid structure and shouldn' t be 23 analyzed as that.
But someone should have gone back, at least 24 to verify the assumption that if it is considered rigid, is it 25 really a ri2id structure?
l l
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]
1 In the design of the ERCW' access cells, as Hai-Bob 2
pointed out, there are a lot of omissions in the calculations, 3
things that should have been considered that weren' t. -
Also is 4
the assumption that the different access cells act as a single l
5 unit.
And,.again, that is another assumption that was not' 6
substantiated and probably' turns out it was not a valid 7
' assumption.
8 There is the assumption of rigidity of steel tanks.
i 9
Again, TVA used it to document TID 70-24 and all the equations 10 in that are based on the fact that tanks are rigid.
- However, i
11 TVA didn' t go back and verify that the tanks they installed i
12 actually were rigid and that those equations were therefore 13 applicable.
14 The basic consideration which we feel TVA missed was i
15 the failure to evalusr.e sheer in walls and slabs.
I' m not a -
I 16 civil engineer, but from what I understand' talking to our team 17 members, that is a basic thing that everyone does in design.
18 Again, this was not considered by TVA.
19 There are questions of the generation of the floor i
i 20 response spectra, which again TVA in a later analysis performed l
i l
21 I guess early this year, identified that at least for the l
22 vertical acceleration in the steel containment vessel, you 23 know, you are probably looking at maybe seven times higher 24 acceleration than was used in the original design.
You are 25 going to get acceleration levels probably as high as 2.5 to 3 Heritage Reporting Company L
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1 gs which are pretty substantial.
2 Also, we-found that TVA has deviated from.the ACI 3
Code 318-1963 which is an AFSAR commitment essentially in 4
regarding the placement of REBAR and reinforced' concrete.
- Now,
^
5 many codes essentially state, well, they basically give you an I
l 6
out.
If you don' t use the prescribed method in the code, at.
l 7
least you should be able to Justify the design that.you do use.
)
8 However, we did not really'see this Justification for u
9 deviations from the code.
1 10 In addition, TVA used a lot of their own internal 11 standa'ds and I guess the team felt that we hadn' t had time to r
12 assess the validity of the standards..
They don' t necessarily
- 13' conform to what people think of as a standard industry' 14 practice.
I 15 Again, we have a large concern between equipment 16 support calculations and the design details that implement 17 those calculations.
As Hai-Boh' pointed out, calculations are 18 based on certain thicknesses of steel embed plates, lengths.of 19 bolts, certain numbers and thicknesses of bolts.
However, when 20 we go to essentially the construction drawings, we find ~that.
21 there are discrepancies:
lesser number of bolts, thinner 22 bolts, thinner support steel.
So, there is a definite miss 23 match between what was analyzed and wt.a5 is actually in the 24 plant.
I 25 Also, was.the. failure to consider overturning moments i
g_
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1 in support designs.
Again, basic, what we feel is a basic j
2 consideration that was overlooked.
And, also, the structural 3
analys'is of the Tornado Missile ' protection 'for the ERCW pumping 4
stations.
In that area, we feel that there were a lot of 5
design features in that design that TVA didn' t consider.-
So, l
6 what does it all mean now that we sit back and.lookJat it?
.)
7 Well, we think that maybe Just to clarify
.I guess I B
saw a statement in--the paper this morning,that the nuclear 9
expert, TVA nuclear expert said that - the NRC was of the opinion 10 that the structures would collapse under:an earthquake or they 11 would collapse under a tornado.
I think that was a little bit 12 overr,tated.
13 What I will say, thoug'h, is I-think based on the 14 calculations that exist, I don' t think that-we e,an determine 15 the structural adequacy of the buildings.
Now, that is not'to 16 say that they are not going to come out okay once they are 17 reanalyzed.
All I think we are:saying now at this point is 18 that based on the calculations we have seen and the' omissions 1
19 in the calculations, we don' t know until those' areas have been 20 addressed whether or not the design is adequate.
So, we still 21 need information to review.
i 22 What we did suggest to TVA and, actually, more of a 23 request was that we think.TVA should conduct a comprehens'ive 24 review of structural calculations for the five major safety 25 related buildings on a sample basis.
And we think -- I will Heritage Reporting-Company (202) 628-4888 1.
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name the five buildings:
the reactor building, the auxiliary 2
building, the control building, diesel generator building.and 3
the ERCW pump house, i
4 Further, we feel that the review should be conducted j
i 5
by independent engineers.
And just to clarify that, by.
6 independent, we mean that people that'may be employed by TVA 7
now, but however did not participate in the original design, 8
and TVA is free to use contractors that they have available.
l 9
We think that the review should include a substantial' 10 sarnple of all major design features, such as structural steel 11 design, the reinforced concrete design, including foundations, 12 floors, walls, columns and roofs.
Masonry walls in the l
13 buildings, also equipment anchorages and equipment supperts.
'l 14 And we also feel that TVA needs to look at the' design i
i 15 construction interface, particularly in light of the concern j
I 16 raised regarding the RAWL anchors, th.e fact that RAWL anchors k
17 were specified on the drawings, however, they may not have been j
18 installed in the field.
s 19 And, also, there is -- again, the inconsistencies 20 between the calculation detail drawings for equipment support.
I 21 I guess since we have two conflicting pieces of information, j
1 22 we don' t really know what is out there.
Is the analysis right 23 or are the drawings right?
Maybe the drawings are right and 24 the analysis needs to be correct.
I think TVA needs to take a L'
look at that.
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In addition to this separate program which I will put 2
aside for a minute.
I think:specifically relating to the IDI 3
concerns, I think'TVA needs to do 100 percent review in five 4
areas and I will go through those quickly.
I think that you t
5 need to take another look at the seismic' response spectra 6
generation for all the buildings that contain safety-relateo 7
equipment.
We think that on 100 percent basis the design for G
sheer in walls and slabs needs to be reviewed.
9 We also think that in tornado missile protection 10 should go back and reanalyze the roof of the ERCW pump. house 11 and we limit it to that because we think the rest of the design 12 is adequate.
13 We also think that the dikes and access cells and the 14 stability of those needs to be addressed fully.
And, also, TVA 15 on a 100 percent basis-needs to go back and review the Category 1
16 I steel tanks to determine whether or not they are. flexible or 17 rigid.
i 18 I would like to make a couple of general observations 19 regarding the inspection in general apart from civil.
It is j
20 difficult to do an inspection like this and there is a lot of l
21 information that is coming across at us and going back and l
22 forth.
So, I am trying to take the time and step back and say, 23 "Now that we have all these, are there any common threads?"
24 And the range, what we think could be generic problems with 25 TVA.
And we thought about this at great length yesterday and-Heritage Reporting Company (202) 628-4888 8
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we have come up with a couple of things that we think TVA might 2
be -- that we pass on to TVA for their consideration.
3 The first area is I.think there seems to be in some 4
areas a lack ofetimely corrective action.
Now, for example, j
5 seismic analysis in the steel containment vessel and the 6
problems related thereto.
This was something that TVA was q
7 aware of in 1985.
However,'the calculation was just redone 8
early this year.
So, it is-essentially a two-year span or more
)
9 that this was not acted on.
And, obviously, as most people
' i 10 know this regeneration of'the response spectra, any 11 discrepancies in that could cause a substantial amount of work 12 and requalification of equipment and anything_else that needs i
13 to withstand an earthquake.
14 Also, the ERCW design pressure,'again, we saw.ECNs 15 that go back to 1986.
And we still find it is not totally 16 resolved today.
17 One thing we thought that was -- and.I guess this is 18 more of an observation.
It appeared to the. team that from the 19 different findings that we saw that TVA lacks systems l
20 integration function.
It appears to us that there is no 21 essential group that really can assess the safety significance 22 of different things.
One group that has the. big picture, s
23 essentially, of things work and how things.need to fit 24 together.
t 25 And there's a couple of examples.
In' the station air-Heritage Reporting Company (202) 628-4888 i
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compression brake isolation, for example.
The radiation j
2 nonitor, the fact that the thing will saturate during accident j
l 3
conditions, it seemed like the design is kind of focused in one 1
4 area.
people are wondering about, you know, looking at the
-)
5 effluent monitor or monitoring effluent radiation, however, not 6
really considering the fact that this was also used in an 7
accident besides normal operation.
8 Appendix R problem with'the indicate lights on 9
traveling screen.
It appeared to us that there was some 10 confusion within different areas of TVA as to whether or not
)
11 the traveling screens were safety related or the screen watch 12 pumps were needed after an accident.
13 There are a couple of others.
The fuse coordination 14
.between Class 1 anomaly, it appeared that the significance of 15 the isolation between 1 anomaly was not totally recognized.
16 You know, it is a hard thing to quantify and, again, 17 this is really an observation on our part, but there seems like 18 there needs to be one essential group of people that really 19 understands the safety significance of the different systems 20 and how they all fit together and can overview and make sure 21 that people are not 1 coking at things essentially with blinders 22 on and that they can assess all the implications.
And there 25 are many in a nuclear plant.
24 MR. GRIMES:
You might may that based on the team's 25 working in other organizations with such a function.
4 Heritage Reporting Company (292) 628-4888
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MR. IMBRO:.Right.
Also, we feel'that there may be 2
a problem in design verification.
For example, in the civil 3
area, particularly, these are the findings that we came up with-4 and essentially they are baseline calculations that were 5
checked and reviewed.
Again, they are not recent calculations.
6 They were calculations done, say, back in the early Seventies j
7 or in mid-Seventies.
8 So, you kind of wonder, well, what does a check 9
connote?
You have another engineer that reviews calculation 10 and signs off on it and misses your really, what we consider 11 basic things, was the checker not qualified to do the job or l
12 did he Just review it and sign it off?
It doesn' t give us a q
)
13 good feeling, you know, that the checking process didn' t really 1
14 seem to be adequate.
15 Also, for example, dimensions on pipe supports.
That 16 is a problem that Andy mentioned.
There was' incorrect 17 dimensions that were used in calculations.
Again, all this was l
18 checked information.
l 19 The environmental qualification for the mild 20 environment, at least, particularly in the ERCW pump house.
21 The equipment really didn' t match the temperature profiles that 22 were specified in different TVA documents.
23 Another example would be the. improper use of the 24 stress intensification factors from B3011.
Again, these are 25 things that should have been picked up at a normal checking Heritage Reporting Company (202) 628-4888-
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1 process or design verification process, but weren't.
So, we 2
think that there may be some basic problem with how.TVA does.
j 1
3 their design verifications, j
.l 4
And I guess the last area I had'was it seems to be i
5 that there is a lack of timely implementation of operation j
6 procedures.
And, in some areas such as -- going back to the j
l 7
ERCW design pressure, there were, I guess some statements that '
8 were to be put i n, system operating instruction, SDI, regarding 9
header pressure control.
This was again something that was l
10 identified a ways back and has yet not been incorporated in the 1
11 operating procedures, although we have seen drafts of those..
12 In the area of screen wash manual operation, screen 13 wash essentially was initially automatic.
However,.the 1
l 14 automatic feature was disabled, but we would have expected at
'l 15 least that in a timely fashion, operations would have picked up i
16 the fact that this needs to be incorporated into the operating j
17 procedures.
Now, we understand that TVA may.be doing the 18 screen washes and some manual operation.
But it is not really 19 proceduralized.
So, I think there needs to be a more close 20 communication between the operations and the engineering staff.
21 So, that essentially concludes the overall 22 observations we had.
And, again, these are preliminary.
We 23 tried to pull them together yesterday, but I think that this i
24 essentially represents the consensus of the team as to where we 25 think their areas are weakest ' that TVA may need to look atf l
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1 further.
H 2
Just a quick note on schedule, Just to review what.
3 everybody already knows.
On October 9th, we are due letter --
i 4
we owe a letter to TVA to define-fully the. restart issues.
5 What we. mentioned today are some of the restart issues, the 6
onus we consider most important and have the most impact.
7 There are probably a few that we haven' t considered, but we 8
think those are more of a minor nature.
For example, minor 9
changes to FSAR and things like that, documentation things.
1 1
l 10 On November 6, according to our schedule, we owe you.
)
11 a completed inspection report and we will try and do that.
J 12 Also, in -- we understand that there in new information j
l 13 available and we will try and make ourselves available to do 14 that.
And we were planning on, Just for rough planning j
15 purposes right now, to come back maybe in late October or early
[
16 November, maybe just before or after the report is issued, to 17 do an inspection of TVA corrective actions.
And we would like 18 to really focus on actions that are corrected, not really come 19 down to inspect the things you intend to do.
We would rather 20 restrict our inspection to when you actually finish things and 21 we have something solid to look at.
22 And, again, going back to this additional program we-23 think is necessary in the structural area.
That will be 24 handled as far as I am concerned as apart, separate from the 25 IDI.
And the IDI will then address the specific functions in Heritage Reporting Company (292) 628-4888 d
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64 1
the civil structural area.
I think the additional structural i
2 calculation review program should be more properly addressed by 3
TVA as part of their calculation program that is currently-l 4
ongoing.
5 That's all I have to say.
I think Brian would like 6
to add something.
7 MR. GRIMES:
Yes, I wanted to Just clarify the issue j
I 8
that was raised earlier on new information that had been I
9 proffered by TVA but not accepted by the team for review.
And 10 I just want to put that in a little perspective.
]
'1 11 The design inspection methodology is to perform an in l
12 depth inspection of a single system as representative of the 13 entire design process.
And from this, look at a system as it 1
14 stands.
We try to draw Deneric inferences for the whole l
15 design.
Our usual practice in a design inspection is to 1
16 establish a cut-off date beyond which new calculations are not 17 considered.
This is related to the announcement of the 18 specific system which is to be inspected.
This is to allow the l
19 team to not have to look at what I call wet ink calculations, 1
20 which may have been done in anticipation or as a result of the 21 team inspection.
Considering those, we believe would distort 22 our picture of the design as it stands and limit our ability to i
23 extrapolate those conclusions to other parts of the design 24 which had not been similarly amended.
25 I have, in the structural area, spoken with the team Heritage Reporting Company (202) 628-4888 i
i
j j
65 1
members and I know of no incidence in which the team declined 2
to review relevant information which is related to the adequacy f
3 of the design as it stands.
i 4
In fact, the opposite appears to be true that the I
5 method of the inspection of the team is to request and review l
i 6
such information.
I would also note that in the structural 7
area, most of the significant issues were identified early in:
B the inspection process.
9 I think it is important to distinguish between the 10 information bearing on the adequacy of the design as it. exists i
11 which is relevant to our inspection conclusions on what 12 corrective actions may be.necessary, such as in the structural 13 area, an increased scope of sampling and, on the other hand, 14 the review of corrective actions in response to these findings.
l 15 And the team in this case I believe gave top priority to the i
16 inspection process itself to look at existing design.
I 17 There will also be a structured inspection process, 18 as Gene mentioned, to look at your corrective actions, but this 19 should not be confused with the current inspection or the 20 development of the current inspection report which defines the 21 problems on which that corrective action program must be based.
22 So, I thought it was just worth a few minutes to try 23 to make sure everybody understood why we were focusing on 1
24 existing design.
25 MR. KEpPLER:
Well, I think'it is still important, Heritage Rwporting. Company (292) 628-4888 l
a 66 1
though, that if there is information that relates to the 2
findings from this inspection,-which I understand the TVA feels 3
they have, we need to have that information.
4 MR. GRIMES:
Yes,'we would be most happy to get that 5
as soon as possible.
6 MR. WHITE:
I, first, in responsv to what you are 7
saying, Mr. Grimes, I have no quarrel with the fact that you 8
had to have a cut-off date.
I told Mr. Imbro earlier today j
9 that in his position, I would have done the same thing.
There 10 has to be some date at which you have to say, " Don' t give me 11 any more information.
I' ve got to write a report.
I' ve got to 12 prepare for this meeting."
13 I have no quarrel with that.
And Mr. Imbro is the 1
14 team leader.
It is his responsibility to determine when that l
15 is.
So, there is no quarrel.
16 I would like to say a couple of things.
One is I 17 wanted to thank Mr. Imbro personally and, through you, the 18 members of your team for your hard work.
'And they worked hard.
19 For your cooperative attitude in this whole effort.
I think, 20 Mr. Imbro, you and your team have -- you know, this is really, 21 no matter how you look at it, it is a unique first of a kind 22 effort.
And I think we also have to put that in the right 23 context that I understand the difficulty, I truly do, of 24 looking at a plant designed in the Sixties, built in the 25 Seventies, and now inspected in the late Eighties in. trying to Heritage Reporting Comp.any j
(202) 628-4888 l
a 67 3
1 get your mental attitude necessarily I think an' impossible 2
thing to do to say, "Well, how would I have looked at this in 3
the Sixties and Seventies based on what the industry knew in 4
the Sixties and Seventies."
)
i 5
In the late Seventies and certainly in the Eighties,
{
l 6
the industry has, with regard to our knowledge of how to go l
7 about looking at things and even new codes and so forth, we i
I 8
look at things differently.
I understand, therefore, the 9
extreme difficulty each of you must face in trying to get -your l
l 10 mental attitude to What would I have looked at if I were here 11 in 1960, would it have been -- or ' 70's, would that have been 12 acceptable and, therefore, is this just like any other plant j
13 built -- designed and built ~in that time?
i 14 I want to thank your people because I think they have i
15 triec to do this.
And, as I say, maybe it is impossible, but I 16 think they have given it a good'try.
17 The other point I would like to make is that I 18 understand that your conclusions and your recommendations are 19 based on the information you now have.
You couldn't do it any 20 other wise.
And I understand that.
I think-we have other 21 information available to you that I think in many cases will l
22 persuade you -- and I don' t blame you for this.
It is our --
23 it is my responsibility to give you the information.
It is not 24 your responsibility to go in our file cabinets and fird it.
25 So, it is our responsibility to provide that _ to you.
And I Heritage Reporting Company (202) 628-4888
e 68 1
think when you see some of this, I think you will be persuaded 2
that some of these problems perhaps are not as severe as what 3
you now think based on the information you have.
4 So, we look forward to our meeting next week.
I 5
understand it is already scheduled for Wednesday.
And we hope 6
at that meeting to provide you a lot of information.
And, in 7
some areas, necessarily, we will tell you the corrective B
actions we intend to take if there are -- and there will be, 9
I' m sure, some of those.
10 MR. WHITE:
I think it is important that your people 11 and our people work closely, particularly, with respect to 12 prioritization of the efforts that need to be done, dealt with 13 here.
Obvious 1), the civil structural area is going to be a 14 major issue with us.
There are other areas that I think, as 15 you people look at it and as we look at it further, will have 16 schedular implications that we will want to focus attention on 17 quicker.
So, I think that is an effort that needs to be 18 undertaken on your side as well as our side, but I think it is 19 important to start off next week particularly in the civil 20 structural aroa.
21 Let me add one comment to what you have just seid.
22 You talked about the complications, the difficulty of doing an 23 inspection of this type.
For whatever reason, TVA didn' t 24 receive an IDI at the beginning of this, so, when it got 25 licensed, I don' t want to defend or attack that comment, that Heritage Reporting Company (282) 628-4888
n,
,~
]
e 69 i
J 1
situation.
But.it was one of the very.few plants and, in fact, 2
it may have been the only plant that did not receive one since
)
3 the TMI accident.
4 However, we have not only looked at NTOL plans this I
I 5
way, this team has gone back at plants older than Sequoyah.
j 1
6 Efforts have been done at Dresden.
Efforts have been done at j
7 Fort Calhoun.
And there may be others, for all that matter.
8 In general, we find t hat TVA Sequoyah is better from a design 9
standpoint than Dresden and Ft. Calhoun, which you would i
l L
10 expect, and less than what you would expect at an NTOL today.
l 11 Not a very profound statement.
But I think the 1
12 message we want to leave you with is the civil area, what is 13 the civil structural area was an area that came out much lower f
l 14 than our expectation based on this type of experience that we 15 have had.
So, that is the area that is burning with us right l
16 now.
Not to overlook the other points that were mentioned, but j
17 that's the one that needs the primary emphasis on both parts.
18 And it is apparent to me, as we sat here and talked, that the 19 people on two-thirds of this table feel very strong that this 20 has a strong scheduler implications with you.
And I hope it Ei proves out that you are right.
I hope you are able to dissuade 22 our concerns.
But right now, it is a big issue with us.
23 So, we look forward to our meeting on Wednesday.
)
I 24 Thank you very much.
l 25 MR. ZWOLINSKI Let the meeting stand adjourned.
Heritage Reporting Company (282) 628-4868
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(Whereupon, at 11:05 a.m.,
the meeting was 2
adjourned.)
3 4
5 6
7 8
9 10 11 12 13 14 1
15 16 17 18 19 20 21 22 23 24 25
+
Heritage Reporting Company (202) 628-4880
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1 CERTIFICATE 2
3 This is to certify that the attached proceedings before the 4
United States Nuclear Regulatory Commission in the matter of i
5 Names Findings From the Integrated Design Inspection (IDI) at TVA 6
7 Docket Number:
8 Place:
Knoxville, Tennessee 9
Date:
September 11, 1987 10 were held as herein appears, and that this is the original l
11 transcript thereof for the file of the United States Nuclear 12 Regulatory Commission taken stenographically by me and, 13 thereafter reduced to typewriting by me or under the direction
\\
l 14 of the court reporting company, and that the transcript is a p
15 true and accurate record of the foregoing proceedings.
l 1S
/S/
btw fl/ E G /Vl/ E.& E L.
17 (Signature typed):
Dan Neunuebel l
18 Official Reporter f
19 Heritage Reporting Corporation 20 l
1 21 i
22 23 24 I
25 Heritage Reporting Corporation (202) 628-4888
_