ML20148Q467
| ML20148Q467 | |
| Person / Time | |
|---|---|
| Issue date: | 01/22/1988 |
| From: | Advisory Committee on Reactor Safeguards |
| To: | |
| References | |
| ACRS-T-1637, NUDOCS 8802010117 | |
| Download: ML20148Q467 (290) | |
Text
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RC23l-Af37 L, R ~1 \ A _
UNutD STATES NUCLEAR REGULATORY COMMISSION IN THE MATTER OF: DOCKET NO:
., STRUCTURAL ENGINEERING
/
MEETING ,
O LOCATION: ALBUQUEROUE, NEW MEXICO PAGES: 1 - 285 t
DATE: JANUARY 22, 1988
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1 PUBLIC NOTICE BY THE
([1) 2 UNITED STATES NUCLEAR REGULATORY COMMISSION'S 3 ADVISORY COMMITTEE ON REACTOR SAFEGUARDS 4
5 6
7 The contents of this stenographic transcript of the 8 proceedings of the United States Nuclear Regulatory ,
5 9 Commission's Advisory Committee on Reactor Safeguards (ACRS),
10 as reported herein, is an uncorrected record of the discussions 11 recordsd at the meeting held on the above date.
12 No member of the ACRS Staff and no participant at 13 this meeting accepts any responsibility for errors or ,
() 14 inaccuracies of statement or data contained in this transcript.
15 16 i 17 18 -
19 20 21 22 23 24 25 O Heritage Reporting Corporation (202) 628-4888
t i
l TRANSCRIPT OF PROCEEDINGS BEFORE THE NUCLEAR REGULATORY COMMISSION ALBUQUERQUE, NEW MEXICO i
., IN RE: THE ADVISORY COMMITTEE )
ON REACTOR SAFEGUARDS )
STRUCTURAL ENGI_NEERING )
SUBCOMMITTEE MEETING BE IT REMEMBERGD THAT at 10:30 a.m., on Friday, the 22nd day of January, 1988, the above-entitled matter O came on for hearing at the AMFAC Hotel, Valle Grande Room, 2910 Yale Boulevard, S.E., Albuquerque, New Mexico 87106, before CHET SIESS, Chairman; and the following proceedings j were reported by William C. Beardmore, A Certified Shorthand Reporter of:
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APPEARANCES B 2 3 3 SUBCOMMITTEE MEMBERS 4 Chet P. Siess Jesse C. Ebersole 5 5 Paul G. Shewmon David Ward 6 6 J. Carson Mark Mike Bender 7 7 Elpidio G. Igne 8 8 9 9 1p 10 11 11 12 12 )
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TABLE OF CONTENTS 3 2 PAGE NO.
3 3 PROCEEDINGS,. FRIDAY, JANUARY 22, 1988 2 4
4 OPENING COMMENTS - J. Costello 4 5 5 DISCUSSION OF THE CONCRETE MODEL TEST 7 Overview of the Test and Results of the 6- 6 Test and Post-Test Inspections - D. Horschel 7 7 ' Blind' Predictions by 10 Organizations - 72 D. Clauss 8 8 LUNCHEON RECESS 111 9 9 AFTERNOON SESSION, FRIDAY, JANUARY 22, 1988 112 10 g 10 (m/ DISCUSSION OF THE CONCRETE MODEL TEST (continued) 113 i 11 11 Pretest Analysis and Comparison With Test Results - R. Weatherby 12 12 FUTURE WORK ON REINFORCED AND PRESTRESSED 177 .
13 13 CONTAINMENTS l
,, Prestressed Containments - D. Horschel l
CONTAINMENT PENETRATIONS 197 15 15 Investigation of the Leakage Potential of a Personnel Airlock - D. Clauss 16 16 Seals and Gaskets, Inflatable Seals, 226
' 17 17 and Bellows - B. Parks ,
18 18 ADJOURNMENT 285 19 0 19 REPORTER'S CERTIFICATE 286 20 20 21 21 22 22 l 23 23
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I PROCEEDINGS 8 2 FRIDAY, JANUARY 22, 1987 3
4 MR. SIESS: This meeting will come to order.
5 This a meeting of the ACRS Subcommittee on structural 6
engineering. It says here I'm Dave Ward, Chairman for the 7 subcommittee. That's wrong. I'm Chet Siess, Chairman of 8
the Subcommittee. And the other ACRS members in attendance, 9
starting on my right, Carson Mark, Dave Ward -- does the '
10
(} 11 microphone work? -- Paul Shewmon -- can you hear me? -- Paul Shewmon, Jesse Ebersole, and Mike Bender, a consultant for 12 us.
13 The purpose of the meeting is to review the
() 14 concrete model test, future work on reinforced and 15 prestressed containments, and future efforts on containment 16 penetrations and seismic issues. Recognizant staff member 17 of the meeting is Elpidio Igne, sitting on my left when he 18 sits down. l 19 The rules of participation in the meeting have 20 been announced prior to notice and published in the Federal 21 Register on January 14th. The meeting is being conducted in 22 accordance with the provisions of the Federal Advisory 23 Committee, Acting Government, Sunshine Act.
I 24 We've received no written statements or requests 25 to make oral statements from members of the public regarding i
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today's meeting. And, as usual,-we're keeping a transcript, 8 2 and I'll ask each speaker to first identify himself or 3
herself, and then, I think, try to use the microphone if you 4
have one. If not, just speak loudly enough so that the 5 Reporter can hear you.
6 We're starting a little late. I don't who decided 7 we could go out there and back in an hour and a half. It.
8 was a nice try. I think we will meet the luncheon time on 9
the agenda sometime around 1 o' clock, maybe a little bit 10
[} 11 before, depending on where we are in the program and then just break at that point and come back.
12 I think everybody has a copy of the agenda. Al 13 just passed out one which is Revision 2, which I haven't
() 14 15 seen.
Does anybody have any questions about the agenda 16 or do any of the subcommittee members have any other 17 comments they would like to make at this time?
18 Looking at the agenda, Walt von Riesmemann is not 19 able to be with us. He has an illness in the family and he 20 had to leave town. But who --
21 MR. COSTELLO: I guess I could start.
22 MR. SIESS: Yeah, but who's going to take 23 Walt's place?
24 MR. COSTELLO: Yes.
25 MR. SIESS: Who?
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MR. COSTELLO:
8 2 introductions and things like that.
I'll do a lot of the 3
MR. SIESS: All right.
4-If there are no comments, let's start in then with 5-Jim Costello from the NRC Research Staff.
6 7 OPENING COMMENTS 8
9 MR. COSTELLO: Good morning. Thank you, 10 Mr. Chairman. I have passed out one package of handouts, U
and I would like to just emphasize a few things in them.
12 The discussions today center around our NRC-13 sponsored program on containment integrity. The overall 14 objective is to provide a reliable method by which you can 15 make estimates and maintain performance with emphasis on 16 qualifying the method by comparison against experimental 17 data.
18 The members of the Sandia team who will be making 10 presentations today are outlined on this viewgraph except 20 for Dr. von Riesemann, who was unable to be here.
21 The next two slides in your package are the way 22 the Sandia presentations have been structured to meet what 23 we believe is the intent of the agenda and also to utilize 24 the expertise in certain areas of members of the Sandia 25 Staff, h'lDlQ NlDl4 1 bb Il b suavies a Aconi ofexcellence
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1 If this is agreeable with you, we are prepared -- ;
8 2 everyone is available all day, so we are prepared to march 3 through in this fashion or circle back at any time if you 4 would like to. ,
5 Right now, we will be starting with the discussion 4
6 of the concrete model tests. ;
7 MR. SIESS: Excuse me a minute, Jim.
8 MR. COSTELLO: Yes, sir.
9 MR. SIESS: Let me check with the 10 Subcommittee and find out if anybody has to leave early.
11 And by carly, I would say before 4:30. ,
12 Okay.
13 MR. COSTELLO: And if it's agreeable to the
(} 14 Subcommittee, we will start off by the sequence of '
15 presentations on the concrete model tests. We'll then i 16 follow with future work on concrete containments. And then i
17 we'll come back to the completion of work on steel 18 containments; that is, the application of results of the l
O 19 scale modeling tests to a Sequoyah containment. And then we l 20 will get separate topics beyond containment penetration, l 21 first try to focus on -- is there a problem question -- is 1
22 there a problem, shall we say, inside the capacity of some l
23 containments. ,
24 MR. SIESS: Jim? i 25 MR. COSTELLO: Yes, sir.
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MR. SIESS: I like that organization, but let 8 2 me suggest a way of approaching it here. I think what I 3 would like to hear -- and I think it will come out the way 4
you've got it -- is, what were the questions you were trying 5 to answer about containments. At this stage of the game, 8 what have we learned and then what are the remaining 7 questions and what do you propose to do about them.
8 MR. COSTELLO: Well, I believe we have 9 that --
10 MR. SIESS: I believe that's about the way 11 you've got it covered. I would just like to get some 12 emphasis on questions and answers or, rather, simply 13 results.
14 MR. COSTELLO: I guess Item 3 -- the basis of 15 Item 3 speak to what we think we've learned so far on 16 concrete containers. Item 4 speaks to what we think we have 17 to do to pose the question. Item 5 really speaks to coming l 18 to a close on containment closure on steel containment O 19 questions. And then 6 and 7 are mixes of -- over somewhere 20 in the (inaudible) stage.
21 I guess if we run out of time, of course, it would 22 be possible to defer Topic 7 until a future meeting, or you 23 can have (inaudible), whichever the Chairman would prefer.
24 MR. SIESS: That sounds good.
25 MR. COSTELLO: With the Subcommittee's ImMNEY h N W MW sEnvies a hrcoid of exccilence
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agreement, I would like to ask Mr. Daniel Horschel, who 8 2 conducted the tour out at the model this morning and who was 3 the project engineer in charge of the model construction and 4
test to give his presentation.
5 6
DISCUSSION OF THE CONCRETE MODEL TEST 7 Overview of the Test and Results of the Test and Posttest Inspections 8
9 MR. HORSCHEL: Thank you. My name is Daniel to Horschel.
11 Excuse me, Dan.
MR. SIESS: What Al is 12 paosing out is a quick look on the low pressure.
13 MR. HORSCHEL: Well, there are three things
(} 14 that he is passing out. One is a copy of the viewgraphs, 4 15 one is a quick look at the low pressure testing, and the 16 last is a quick look at the high pressure testing.
17 MR. SIESS: And Igne distributed the quick 18 look on the high pressure to the members of the O 19 Subcommittee; so you might already have that.
20 MR. HORSCHEL: I would like to first begin 21 with the objective of our containment testing. Again, this 22 is to generate data by testing containment models. The data 23 can then he used to qualify methods for reliably predicting 24 the response of LOCA low water reactor containment buildings 25 for severe accidents.
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1 I would like to review some of the instrumentation 8 2 that we have on the containment model. As I mentioned 3 during the tour, we have about 300 channels bedded in the 4 We also had conrete wall. Most of those are strain gages.
5 some bondable gages on the rebar. We had 161 rosettes on 6 the inside of the liner, for a total of 483 gauges. We had 7 strip gages, which was a total of 101 single gages on the 8 strip gages, 59 single gages, 137 displacement transducers, 9 thermocouples. We had embedment gages in the concrete. Of 10 course, we had pressure transducers, some resistence
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11 temperature detectors, inclinometers, weather. We had one 12 bolt link and two flow meters, for a total of about 1,200 13 transducers that were contained in the model.
(~') 14 In addition to this, we also had about 12 video 1
15 cameras and recorders that monitored the different places 16 throughout the containment. One of those was actually 17 inside the containment and (cough) control capabilities.
f-y 18 We also had several still cameras located at
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19 different stations about the model and photographed the 20 containment during both the low pressure tests and the high 21 pressure tests.
22 MR. SIESS: I assume that we wouldn't find 23 much of interest at looking at the video.
24 MR. HORSCHEL: Since the containment is still 25 there, that is basically true. About the only thing that we
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9 1 would find more interesting -- we really don't have a copy 8 2 of it in my presentation or you really couldn't see up there 3 were the uplift of the basemat. That was much more 4 noticeable during the pressure testing and that's only 5 captured on the video -- well on the video.
6 Just a brief review of our testing schedule. We 7 began our structural integrity test, which is a standard 8 test on any full-sized containment, on July 6th through 1
9 10th. That's where we pressurized the containment in steps 10 to 1.15 times its design pressure. We did mass cracks at 11 six selected locations throughout this test. And that 12 report that you have in your hand that was handed out really 13 goes over that full test and some of the results from the 14 structural integrity test.
)
15 As far as I'm concerned, nothing really unusual 16 was found during that test.
17 We then continued on the next week in July and did 18 integrated leak rate testing on the containment model.
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39 First we did it with no orifices in the containment to see 20 what its non-leakage rate was in the system. The result 21 from that was about .15 percent mass per day time from the i 22 containment, which we believe most of that was coming from 23 actually leaks in the valve guide rather than the i 2 '.
containment itself. We considered that to be a very 25 acceptable level.
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I MR. MARK: At what pressure level was this 8 2 you referred to?
3 MR. HORSCHEL: That's at 46 design -- at 4
46 psig which is the design pressure of the containment.
5 That's all --
6 MR. MARK: You've got a seventh of a percent 7 per day.
8 MR. HORSCHEL: .15 percent per day at 46 9
psig.
7, 10 MR. SIESS: .15.
-J 11 MR. HORSCHEL: We also put orifices in there 12 and tested some small orifices to see what type of leak 13 rates we would get with those. And one orifice gave us 14 about 11 percent and another orifice gave us about -- I f^')
s, 15 believe it was 35 percent leakage per day. One larger one 1G was about .137 inches in diameter, the smaller one was 17 .070 inches in diameter.
l 7s 18 MR. SIESS: .07 inches in diameter gave you
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20 MR. HORSCHEL: I believe it was about 21 11 percent.
22 MR. SIESS: So did anybody calculate what 23 size opening it would take to get .15 percent?
l 24 MR. HORSCHEL: We didn't go through that.
25 I'm sorry.
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We did some leakage testing on their equipment 8 2 hatches. And finally we concluded during the end of the 3
month on July 28th through 30th the high pressure test.
4 The rest of my presentation today will really 5
concentrate on the high pressure test.
6 MR. SIESS: Now, the high pressure test, it's 7 true you went up over 150 psi?
8 MR. HORSCHEL: Up through 145 psi gages, yes.
9 This outlines our loading schedules for the first 10 day.
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11 the SIT, so we took fairly large steps for the first 50 psi 12 of the loading schedule. After we exceeded that, wo began 13 to reduce our loading step to about 5 psi. As we noticed, 14 not in your response, is an interesting thing happening
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15 about the containment, we reduced them further to 2 to 3 pui 16 steps. On average, each step took about an hour with all 17 our instrumentation scans scanning the containment with our 18 video cameras, and just reviewing data before we went onto
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19 the next pressure step.
20 MR. SIESS: At what pressure was the line 21 unpredicted to yield?
22 MR. HORSCHEL: Maybe I could defer that to 23 Randy Weatherby.
24 Randy, do you have a response?
25 MR. WEATHERBY: 110 psi.
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12-I MR. SIESS: 1107 Thank you.
8 2 MR. HORSCHEL: As you can also see from our 3
loading schedule that the test was conducted on around-the-4 clock basis. We were testing 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> a day.
5 Here you can see, as we went beyond 100 psi, we 6
reduced our steps to about 10 psi for the remainder of the 7 test.
8 MR. SIESS: Now, by steps, a full set of 9
instrumentation read after each of those steps?
10
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MR. HORSCHEL: Hand-wired instrumentation --
11 well, let me back up.
12 The majority of the answer is yes. We had those 13 TRAC systems on the outside that made the displacement which
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14 you saw this morning. Those we wouldn't scan every time.
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15 Just because with their resolution, it wasn't appropriate at 16 the lower level to do that. As we exceeded and got the 17 higher pressures, we thought that we could make something in 7~, 18 those TRAC systems, then those would be scanned. But for
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19 the most part the answer is yes.
20 MR. SIESS: Fine.
21 MR. HORSCHEL: Some points of interest along 22 the way that we saw during the high pressure test was No. 1, 23 at 125 we sensed some leakage coming from the vicinity of 24 Equipment Hatch B. Now, how did we sense this? This was 25 also with an acoustic detection system which we had
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I operating real time during the containment tests.
8 2 We had about eight sensors located about the 3 contain.nont so we actually couldn't pinpoint where it was 4
coming from, but we could actually get a general vicinity.
5 MR. SIESS: These were outside the 6 containment?
7 MR. HORSCHEL: Both. We had a couple on the l
8 outside, up there on the sleeves, and some on the ir.71de on 9 the lineer. We really couldn't attach it to the concrete, 10 l
so it was all attached to the steel.
Il MR. SIESS: So when it says that some leakage 12 was thought, was the thought referred to the location or to 13 the exis';ence of the leakage?
14 MR. HORSCHEL: The area where it was coming
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15 from, the location. They feel fairly comfortable with their 16 acoustic detection system sensing that this frequency range 17 does dictate a leak.
- 18 MR. SIESS: It was a leak at 125, but you i/
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19 don't know how big it was and you think it was in the 20 neighborhood of A.
21 MR. HORSCHEL: Of B.
22 MR. SIESS: I'm sorry, of B. I was looking 23 for a letter and the A was up there.
24 MR. HORSCHEL: Should have put quotes around 25 it, fy . _ _ _
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I Along those lines, did try to take a leakage note 2
measurement at 125, but the leakage was so small it really 3
didn't come up in our resolution. If it's a very small 4
leak, it would take a very long time to find -- to get a 5
magnitude of that leak. The larger the leak is the less 6
time it takes.
7 So we continued on. We started noticing something 8
was coming from Equipment Hatch A -- in the vicinity of A --
9 at a pressure of about 138. We also noticed towards the to
./'s conclusion of the test that we had about a half of an inch V
U ovalization of the sleeve of Equipment Hatch A. And as I 12 mentioned before, we had an uplift of the basemat. That was 13 about three-eighths of an inch.
() 14 MR. SIESS: And that half-inch was enough to 15 expose one of the seals?
16 MR. HORSCHEL: Yes. The three-nino 17 (inaudible).
,s 18 Obviously, it was old so it wasn't all the way
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19 around, just a couple of locations. I have some pictures of 20 that I'll show you later.
21 MR. EBERSOLE: May I ask you, was it a basic 22 objective to ensure that the liner would fail at a pressure 23 well below that of catastrophic failure of the reinforced 24 concrete?
25 MR. HORSCHEL: We just used typical design
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1 procedures, and we really scaled our model from typical 8 2 containment models.
3 MR. SIESS: Well, let me -- Jesse, these 4
things are designed for LOCA loads with certain allowable 5 stresses and margins. And the criteria you indicated just 6 doesn't pan up. They don't think about severe accident 7 loads of how it's going to fail. The whole design is based 8 on allowable stresses and margins. The design is based on 9
not failing, it's not based on failing. So they never get r^; 10 around to thinking about how --
V 11 MR. EBERSOLE: Well, the end result of it is 12 that -- however, is, in fact, you do fail at a pressure of 13 lower than this, it would cause cataetrophe failure of the
()
v 14 structured concrete, 15 MR. HORSCHEL: Certainly in this case. How 16 it applies under the containments, I really don't want to 17 speculate at this point.
rs 18 MR. EBERSOLE: Okay.
19 MR. HORSCHEL: And finally, the cracks in 20 concrete surface became much wider. And that is in lieu of 21 forming new cracks. So I think that's an important thing 22 that we learned from this test. Generally the cracks that 23 you have in your SIT are the cracks that you'll see at the 24 conclusion of a high-pressured event.
25 MR. SIESS: What kind of crack widths did you O( ,
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I have at the SIT, millimeter?
8 2 MR. HORSCHEL: They're measured, and again, 3 they're in that report. We started turning them down if 4
they were greater than 10 mils.
5 MR. SIESS: Okay.
6 MR. HORSCHEL: Some of them did exceed 7 10 mils, but there were very few in the SIT test.
8 ME. SIESS: And at the end of the test, how 9 big were your cracks?
r',) 10 MR. HORSCHEL: It was very much as they did LJ 11 today. There were some cracks -- many cracks that were 12 probably as wide as an eighth of an inch and a few 3/16 of 13 an inch and possibly a little wider than that.
( '; 14 Let me mention some of the loakage tests that wo 15 conducted during the course of the high pressure tests.
16 The first one that we feel comfortable in 17 reporting was done at 135, and we had about 11 percent mass 7s 18 per day. That converts to about eight standard cubic feet t !
19 per minute.
20 MR. SIESS: Which hatch is which? Which had 21 the double?
22 MR. HORSCHEL: B was tho one that was 23 doubled.
24 MR. SIESS: Okay.
25 MR. HORSCHEL: At higher pressures --
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I MR. SHEWMON: Is that the one we came out --
8 2 MR. HORSCHEL: You went in A. A came into 3
play at about 138 psi. We did our first leak rate test when 4
we sensed leakage coming from both areas at 140. The 5 leakage then was recorded as being 13 percent mass por day, 6 about 10 standard cubic feet per minute.
7 Our next leakage test was done at 143. The 8 leakage then was recorded as being 62 percent mass per day, 9 about 50 standard cubic feet per minute.
10 Finally, at our maximum pressure that we reached
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V 11 this at, we did three tests at 145. The first, we measured 12 the leakage as being 234 percent mass per day, about 13 185 standard cubic feet per minute.
() 14 Now, that test was actually done from the whole 15 containment model as we felt things were happening there.
16 With the two hatches on B, we decided to close the 17 valve on the inner door and we would eliminate any leakage (m 18 coming through the outer door at B. So we actually expected L!
19 and we assumed really that leak was coming through B. We 20 expected our leakage to be smaller. As you can see, it 21 wasn't. We actually measured 352 percent mass per day or 22 275 standard cubic feet per minute.
23 MR. SIESS: How much time elapsed between 24 those two readings?
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the beginning of the other, probably about five minutes.
8 2 MR. SIESS: You mean to close that change 3 from 185 to 275 occurred in five minutes?
4 MR. HORSCHEL: Okay. We conducted the first 5 test at 145 and got 234 percent per day. That test takes 6 about 15 minutes long to conduct.
7 MR. SIESS: Well, we're talking about 8 minutes?
9 MR. HORSCHEL: 15 minutes.
10 MR. SIESS: Okay.
11 MR. HORSCHEL: We stopped that test, changed 12 the valve over, looked at the data, started our computer 13 program to initiate the second test, which took probably 14 about five minutes. And in eight minutes, we realized that 15 we had about 352 percent mass per day.
16 MR. WARD: But the pressure in the building 17 just stays constant during that test?
18 MR. HORSCHEL: You do pull it off of your 19 valve off system and, indeed, we do lose with some pressure.
20 We probably lost about two or three psi's through each one 21 of these tests and then we filled it back up.
22 At the conclusion of the second test, the one 23 where we measured 352 percent per day, we opened up the 24 valve again and tried to bring it back up to 145, but we had 25 trouble doing that. There finally was a conclusion of the O mmetemy REPORTING SERVlOE aAcorri of ckcciicnce
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I test. We were pu: ting in about 4,000 standard cubic feet 8 2 per minute and just couldn't bring the pressure back up.
3 MR. SIESS: So at 145, you essentially had 4
somewhere a leak that was continuing to increase?
5 MR. HORSCHEL: Yes. I'll get into that in 6
some more detail here.
7 MR. SIESS: You're not going to deal with the 8
hatch problem.
9 MR. HORSCHEL: Now, ignoring that last 10 measurement, 4,000 standard cubic feet por minute, you can Il see the dramatic increase in the leakage rate where it comes 12 from the containment model, especially between 140, 143, and 13 finally at 145. It had happened very suddenly, 14 f~)
v MR. SIESS: How long did it take you to go 15 from 140 to 143 to 1:457 16 What I'm getting at is, suppose you had just sat 17 there at 140. Would it possibly have contiaued to yicld n, 18 that leak.
<j 19 MR. HORSCHEL: The material properties of the i 20 steel do show some creepage. I think if we did stay there 21 for a period of time, especially at these upper pressure 22 levels, it's possible you could have developed a large leak 23 at a lower pressure level.
24 Conversely, I also feel if we loaded a little more 25 rapidly, we might have been able to get a little higher l
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I than 145, 8 2 For example, at 145, we were there for more than 3
one hour while we were doing all these tests. We did 4
standard instrumentation scans, we did the two-leak rate 5 tests, and after we were putting this 4,000 standard cubic 6
feet per minute into the model, we actually did another scan 7 of the instrumentation.
8 MR. SIESS: Well, I look at that curve, and I 9
would say, well, at the first little slope, the 140 up, that 10 slope, I would like to extrapolate one line out and the
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11 other one up. Do you know what I mean?
12 Yeah, instead of going that way, I would go over 13 from 140 and then up.
{} 14 If you left it at 140, let's say it would have 15 been reasonably stable. Now, you move it over to 140.
16 MR. HORSCHEL: This is 3.
17 MR. SIESS: Yeah. But you don't have any 18 points between those two. What do you think the shape of 19 the curve was between those two?
20 MR. HORSCHEL: I guess I would be --
21 MR. SIESS: See, what I'm postulating is, at s 22 about 142, if you would have just held it there, it would 23 have gone up.
24 MR. HORSCHEL: I think that is very possible.
25 MR. SIESS: But not at 140, you don't think?
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MR. EBERSOLE: Let me ask you this: The real 8 2 rise in pressure would como either from temperature, which 3
will be slow and you will be caught inside as well because 4
of failure reject heat or it will come for something like a 5 hydrogen explosion.
6 On the other side of the coin, what if you applied 7 part of that pressure suddenly? Would you expect it to fail i 1
8 earlier or later or higher or lower pressure from the 9
hydrogen explosion in which the pressure loading is applied 10 c
in a very short time?
s 11 MR. SIESS: That's a future issue.
12 MR. HORSCHEL: It's a very different '
13 situation. It really would depend on the loading and what
/ 14 you're looking at. In a dynamic situation, actually those 15 leaks don't mean anything. It's a very dynamic situation 16 with a very big explosion. There's a very small spike 17 inside, it probably won't have much effect on the equipment, r 18 It really depends on what range you're talking about.
( ;
19 There's a lot of parameters that could go in there really 20 answer your question.
21 MR. EBERSOLE: You would think, would you i
22 not, it would take a higher loading, though, witha fast 23 application of pressure?
24 MR. SIESS: Sure.
25 MR. HORSCHEL: Sure. That's generally true, c ---
U maNNgw REPORTING SERV 10E a wcoirl of excellence
I yes.
8 2 MR. SIESS: And if it didn't rupture, it 3
might not be any leak at all.
4 Incidentally, it's interesting if you look at that 5
graph. It starts at 100, which is over twice the design 6
pressure.
7 MR. HORSCHEL: I apologize for that. I 8
should have pointed that out.
9 MR. SIESS: No, .'.t's all right. That's fine.
to
(~1 I'm not criticizing you there.
') .
11 MR. HORSCHEL: I'm not sure whether all your 12 viewgraphs are in, but let me put this one on. I think I'm 13 a couple ahead of you.
14
[; These are leak rate measurements that we did after 15 the test. We actually developed a small gun, if you will, 16 to hold over these small tears in the liner and actually 17 measured the flow through that to see how much flow we were
- 18 p , getting through each of the small tears, not the large L ,)
19 tears, but the small tears. We wanted to see how that came 20 into play.
I 21 Remember, we had a small tear near the one l 22 personnel airlock. We were able to get about 8 standard n cubic feet per minute through that tear at a pressure of 24 125 psi, and slightly greater than that at 145.
25 MR. SIESS: Just a minute. You've given n _ _ _ _ _
U JaaNNmW RENGENNG
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I cubic feet per minute. I'm trying to think percent.
8 2 MR. HORSCHEL: Here I've referred to percent 3 mass per day.
4 MR. SIESS: Oh, okay. I'm sorry.
5 MR. HORSCHEL: And I asked him for more 6 accuracy in these, so keep that in mind.
7 But at 125, it was 12.2; and 145, it was 10.7.
8 Those are typical for, say, three to four of these 9 locations. So it also means to me that since we only had 10
(~'3 11 percent to 13 percent at --
V 11 MR. SIESS: Wait a minute. Why is 10.7 and 12 8-plus less than 12.2 at C7 13 MR. HORSCHEL: Because mass per day, you have
/ ;
la to look at the pressures. Pressure is strongly influencing 15 these. And that's why it's --
16 MR. SIESS: Okay.
17 MR. HORSCHEL: -- an actual reduction.
,c , 18 MR. SIESS: Okay. It's mass por day?
! J
~s 19 MR. BENDER: What do we know about the change 20 in the measurements of the crack during this leakage period?
21 MR. SIESS: A little louder, Mike. I can't 22 hear you.
23 MR. BENDER: Are the crack sizes stable or 24 are they growing? What is it that you envision is 25 happening?
n . _ _ . _ _ .
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I MR. HORSCHEL: Well, the way you're asking 8 2 the question, you're asking for my opinion. And that's all 3
I can offer.
4 MR. BENDER: That's all I expect since you 5 weren't there.
6 MR. HORSCHEL: If irou look at the bottom 7 insert plate, the one below the large major tear, can't you 8 see a large neck region. And that neck region is almost a 9 half an inch long. So if it would have torn, you would have 10
/ about a half inch tear.
11 Down in the other areas where they didn't tear, 12 they're all about a half of an inch in length. So I think 13 the majority of the tears that you see in there more or less
~i 14 just happened suddenly and were stable. The big exception,
(
t 15 of course, is our major tear, the one that was 22 inches 16 long.
17 MR. SIESS: And you don't know whether it ran
,- -m. 18 or just connected up several smaller ones?
i i l V l
19 MR. HORSCHEL: That's very true. If you look 20 at the lower section, you can actually see some areas that 21 are right next to where the start is, and you're not sure if 22 one happened first or they kind of happened concurrently and 23 grew together to be one large tear.
24 MR. BENDER: Well, let me pursue my point one 25 step further.
O lWN NN REPORTlNG SERV 10E a record ofexcellence
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I The ones that were stable, is there any 8 2 rationalization for why they were stable?
3 MR. HORSCHEL: The only thing I can think 4
of -- and again, my opinion.
5 MR. BENDER: I understand.
6 MR. HORSCHEL: The ones that appeared to be 7 stable were near a circular insert plate. To travel 8 vertically, they would have had to go into thicker material.
9 Now, there was one where we didn't the cracked 10 propogation.
. Of course, we just had a horizontal surface, 11 so it could more easily propogate in a horizontal direction.
12 And that's just the concentration of the --
13 MR. SIESS: But you don't really have any 14 basis for saying that a crack propogated from a particular
{' ')
15 location? You have some cracks that apparently got larger, 16 but you don't know whether that was several cracks 17 Connecting up.
- 18 MR. HORSCHEL: True.
\ )
19 MR. SIESS: I mean, you know. In a ductal 20 material, cracks will both get wider and longer. But there 21 was no dynamic propogation. Right?
l 22 MR. HORSCHEL: Yes. l 23 Going back to --
24 MR. SIESS: Go back -- did you skip through j 25 Equipment Hatch A?
,/
\, ---
U lipN19w REPORTlNG l SERVlCE a wcorri of excellence
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l MR. HORSCHEL: Yeah.
8 2 MR. SIESS: Those were little tears?
U MR. HORSCHEL: Yeah. We had four tears in 4
our Equipment Hatch A.
5 MR. SIESS: Okay. Now, where were the stud 6 pull-outs?
7 MR. HORSCHEL: That's Equipment Hatch B. And 8
there you can see the stud pull-out right there.
9 MR. SIESS: Okay.
10 MR. HORSCHEL: That's the upper one as 11 identified, and this is the lower one. So obviously, that 12 upper one didn't tear that size hole until later on in this 13 experiment. It certainly could have been there at a 14 pressure of 140 psig's.
(}
15 MR. SIESS: And that's a 3/16 inch maybe 16 diameter hole, 40 percent?
17 MR. HORSCHEL: Yes.
18 MR. WARD: Dan, how did you make these flow I 19 measurements? You said a gun that --
20 MR. HORSCHEL: Essentially we had a hose from 21 a nitrogen bottle, and then we actually had a handle 22 arrangement seal that we could hold it on to the small tear.
23 MR. WARD: On the inside on the tear in the 24 lining? Okay.
25 MR. HORSCHEL: And in line with that, we had O _
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REPORTING SERVlCE a record ofexcellence
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a pressure gage and a flow meter. So we just turned --
8 2 MR. WARD: Okay. You're just supplying flow 3 from the -- all right. I understand.
4 MR. HORSCHEL: One thing to point out that b you might catch with this is cross-talk between holes. We 6
did find stuff between the upper left and upper right of the 7 Equipment Hatch A. We pressurized one and we actually had 8 to hold our finger over the other one because some of the 9
air was coming back in. Same thing with B.
10 MR. SIESS: Did you do anything on the
)
11 outside to see what kind of an area that stuff was coming 12 out, like soap film or --
13 MR. HORSCHEL: No , not with soap film. We (x- ') 14 tried it with inert gas, but your sensor is so sensitive 15 that as soon as it entered the outside, you would just -- we 16 found it all over the place. But we really couldn't tell 17 either qualitatively or quantitatively where it was coming
,c ~ 18 through, the leakage was coming through.
I \ )
19 MR. SIESS: You could have put a coding on 20 there.
21 I'm not sure it makes any different. But, you 22 know, once there's a hole in the liner, it's going to get 23 out whether it goes through one concrete crack or six, it 24 doesn't really make any difference.
25 MR. MARK: You were using nitrogen?
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1 MR. HORSCHEL: For these tests here, yes, and 8 2 also for the high pressure tests, we used nitrogen.
3 MR. SIESS: A little less viscous than air.
4 MR. HORSCHEL: For high pressure testing, it 5 was just much more convenient to use the nitrogen. And i 6 since you use that for the high pressure test, we wanted the 7 one/one correlation for this test.
8 MR. SHEWMON: Chet, it does make a difference 9 in one regard, in how much particulate plates out in the H3 process. Though that's a detail the NRC can't give anybody 11 credit for.
12 MR. SIESS: And, of course, the model -- I 13 don't think can model that very well because the -- I don't
() 14 know whether that models the crack surfsce or not, you see.
15 That wasn't part of this and it was a very good point. If 16 it's a tortuous path, you deposit more stuff on tha way out.
17 MR. HORSCHEL: And I'm sure the path -- well,
~
18 actually, I would expect the path to be much more tortucus 1 \ )
19 to a four-and-a-half-foot thick wall than it would be for --
20 MR. SIESS: I don't think so. Those cracks 21 were pretty big.
l 22 l The surface of the crack might be different, 1
23 because of the difference in the concrete.
24 l MR. HORSCHEL: The post test inspection: One 25 thing you find when you open up your equipment hatch, as we r ._- -_ _
k> lileNN1N Em CliTlNG SERVlCE a wcord of excellence
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1 mentioned before, that the seal was exposed at the 3:00 and 8 2 9:00 position. We also, of course, realizing concrete was 3 intact and the area of the major tear, however, the wall was 4
delaminated.
5 After the test, you could actually walk up to that 6 and put your hands in that area, probably about a two foot 7 by two foot square area, and it was actually cooler from the 8 rush of nitrogen. You could also knock on that and you 9 could distinctly hear a different sound in this area, as 10 opposed to other areas on the containment wall.
c V,
11 There was little sign of distress that we saw in 12 today's tour in the basemat-cylinder wall junction. As you 13 saw, we removed some of the paint in the area of the I i 14 distressed liner.
w i IS MR. SIESS: Excuse me. What do you mean by 16 delaminated?
l 17 MR. HORSCHEL: Through the wall thickness,
,-w 18 the concrete wall itself, I believe there was some i l 19 delamin3 tion.
20 MR. SIESS: In the concrete?
21 MR. HORSCHEL: In the concrete itself.
22 MR. SIESS: What rakes you think that?
23 MR. HORSCHEL: Because it was so much cooler 24 due to the nitrogen. The nitrogen actually came out 25 adjacent to that penetration and trave >.ed somewhat.
O WNN16EE REPORTING SERVlOD a reconi of excellence
30 -
I MR. SIESS: Why couldn't it have traveled 8 2 between the liner and the concrete?
3 MR. HORSCHEL: It certainly could have, but 4
that wall was cooler there and also, when you knock on that 5 wall in that area, it does give a different sound; it does 6 sound hollow. It sounds like it's just a concrete shell, 7 say, two inches thick. It doesn't sound like it does a few 8 feet away.
9 MR. SIESS: That's the best test, yeah.
10
( MR. HORSCHEL: Yeah. As we also noted in our L.),
11 tour, there are several small tears. And as I j'ist showed 12 you, we measured the leak rates from many of those tears, as 13 it was able to give us some idea of when those tears
() 14 developed in the test.
15 MR. SIESS: Is all the rebar welded including 16 the diaganol rebar?
17 MR. HORSCHEL: Let me defer that again to p la Randy.
l \~J 19 MR. WEATHERBY: The original bars were 20 setting right at the yield point, 145; the hoop bars were 21 yielded.
22 MR. SIESS: What about these?
23 MR. WEATHERBY: The diaganol bars were 24 yielded as well.
l 25 MR. SIESS: They were yielded, too. Okay.
U liENNEW l REPORTING SERVICE a recmri of excellence
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MR. HORSCHEL: One other thing we noted during post test inspection, that each tear or neck region 3
that we found was associated with the study.
4 MR. SIESS: You said "adjacent to," that 6 would mean to one side to me. You mean "at the tear "
6 MR. HORSCHEL: Well, I guess if you look at 7 where it tore, it goes right down the edge of it; that's why 8 I said "adjacent."
9 MR. SIESS: I see what you mean.
^ 10 MR. MARK: You spoke of some patches being
\)
11 cooler, and you deduced that the nitrogen was oozing through 12 that region.
13 MR. HORSCHEL: This is in the area of our
(')
O 14 major tear and it's actually to the wall.
15 MR. MARK: Yes. Do you mean that you or 16 somebody walked up to that damn thing and held your hand 17 against it?
,- 18 MR. HORSCHEL: Yes, sir. After we decreased Li 19 the pressure to 20 psi, we went up to it.
20 MR. MARK: Oh, after you dropped the 21 pressure. Thank you.
22 MR. HORSCHEL: The project is important to 23 me, but not that important.
24 Here just a stretch out of the liner; you can see 25 some of the distress as well as the tears. I want to make n _ . _ _ _
U maNNEW REPORTING SERVlOE a recorri of excellence
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32-I a -- point that out that this shows both the tears and the 8 2 distressed areas.
3 Here, of course, is our major tear. We had a tear next to this personnel airlock. We had two tears here that 5
actually showed signs of leakage. Two ones below equipment 6
Hatch A, they look like a tear to me, but with our little 7
flow heater system, you couldn't get an even flow of 8
nitrogen to these two lower tears, 9
MR. SIESS: So you went through the wall, 10 then.
11 MR. HORSCHEL: In fact, we might not even be 12 through the liner, is that what you meant?
13 MR. SIESS: I mean not through the liner.
14 MR. HORSCHEL: Visually, just looking at it, 15 without any magnification, to my eye, it looked like they 16 washed it.
17 Here we had some neck areas next to this that were 18 very analogous to torn regions in this -- next to this
'19 insert plate. We had a slight denecked area next to this 20 personnel airlock. And we had the two studs tear through 21 this Equipment Hatch B. This is one of our large bore l
22 piping penetrations, scale large bore piping penetrations.
23 We actually found some distress there that wasn't
! 24 too significant. I probably have some plots and I'll show 25 you later that show some of the strength concentrations that O mmw m REPORTING .. ..
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I are associated with the stud and that insert plate.
8 2 MR. SIESS: All of those are at studs?
3 MR. HORSCHEL: All of those are adjacent to 4
studs.
5 To equip the REA model, this is Equipment Hatch A, 6 this is our one instrumer. etion penetration where next to it 7 we had the stud tear and the liner tear.
8 A couple of views from the outside. Close up, you 9 can see how the concrete is cracked just slightly more. We
~1 to do see some places were the conrete was removed. But this w.)
11 general area in here is the area that was cooler to the 12 touch and also sounds different when you knock on it.
13 MR. SIESS: Were those the little spauls?
(~j'; 14 MR. HORSCHEL: Yes. Right here.
L 15 MR. SISESS: Were they there before you took 16 the pressure off, because sometimes you get that when it 17 recovers.
l ,cs, - 18 MR. HORSCHEL: That I couldn't tell you. I l
~
)
19 really don't know. It doesn't show up well in this picture 20 but there is some motion between like a block of concrete 21 here and this other concrete over here. And there was some 22 difference in radial motion.
23 MR. SIESS: Afterwards?
24 MR. HORSCHEL: Yes. This is all post-testing 25 inspection. Let me show you one construction photo before l
l f' 'N, - _ _ . - _ _ _ .
1 L) uvNNwW l REFORTlNG SERV 10E j a reconi of excellence
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I the concrete and rebar was in place. Here you can clearly 8 2 see the insert plate, you can actually see the liner studs 3
where we had the major tear.
4 MR. SIESS: That's the first line of studs 5
outside the break?
6 MR. HORSCHEL: Yes.
7 MR. SIESS: What was that distance?
8 MR. HORSCHEL: Approximately an inch.
9 MR. WEATHERBY: About an inch.
10
,3 MR. EBERSOLE: Tell me, don't you think the
%,.)
11 attachment of the studs translates the stress to the steel 12 and causes it to fail and if they were not there, a failure 13 would occur later?
fv ') 14 MR. SIESS: Uh-huh.
15 MR. HORSCHEL: There's certainly an 16 interaction going on. We'll get to some of that later when 17 we talk about the analysis.
18 Here's an inside view of that major tear.
7 One t
)
l 19 thing that actually and probably should look better in this
]
20 photo than it does in real life, you can actually see some 21 of the shadows where the studs are located. l 22 Again, there is a small degree of displacement j i
23 between the insert plates and the other side of the liner 24 where the tear was located.
25 There's one thing I pointed out during the tour
,x _ _ _ _ _ - . - _
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I but wasn't obviously evident, is the equipment hatch wasn't 8 2 there. Here you can see some of that ovalization. You can 3 see the seal is slightly exposed, and here's that one tear 4
near Equipment Hatch A. I have closer views of each of 5 these shots, each of those locations.
6 Here's the tear. You can almost see the outline 7 of the base of the stud in here. The stud is located right 8 there due to --
9 MR. WARD: That's not through the wall?
10 (N MR. HORSCHEL: That one is.
V 11 Actually, when we took these shots, we didn't even 12 realize those two lower ones were there and we don't have 13 any current photos of thsoe lower ones, to my eye, they are 14
() obviously smaller than this. But it did look like it was 15 through the liner and its neck that far.
16 Here's a closeup view of the ICL. You can see the 17 gumdrop Seal being exposed. Keep in mind there is another 73 18 gumdrop seal that is still in place.
V 19 MR. SIESS: Let me get oriented on that.
20 That's the hatch cover to the right.
21 MR. HORSCHEL: This is the rate for the hatch 22 cover; this is the sealing surface of the sleeve here at the 23 edge of the sleeve.
24 MR. SIESS: And what's the seal?
25 MR. HORSCHEL: The red is the foam rubber;
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I that's the gumdrop seal.
8 2 MR. WARD: Why do you call it a gumdrop seal?
3 MR. HORSCHEL: If you look at it in 4
cross-section, it looks like a gumdrop.
5 MR. SHEWMON: Are these wider than O rings 6 or -- one of the seals -- one of the penetrations -- let's 7 see, one of the -- what do they call these big cylinders 8 that go through entrance hatches overlies more than the 9 other?
10 This is Equipment MR. HORSCHEL: Yes.
11 Hatch A, which only had the one cover. We saw more 12 ovalization there.
13 MR. SHEWMON: You're suggesting, okay, that
/^ 'a 14 the reason was because of the cover or the lack of covers or LJ 15 the design of the reinforcing around it?
16 MR. HORSCHEL: To some degree, you have to 17 speculate on that. But let me tell you what my opinion is:
,- 18 No. 1, the reinforcing is identical, the primary reinforcing
() 19 on each one of those bosses is the same. Local reinforcing 20 is somewhat different. I think the major reason -- a couple 21 of major reasons they're different is, No. 1, the second 22 equipment hatch actually has a softening, if you will, of 23 the liner. It's got that tapered in section to the boss 24 face. You saw that when you pulled on that, you actually 25 tore some of the stud in that soft -- it's hard to transfer g ____
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I the load into the sleeve barreling. I think that is one of 8 2 the most important.
3 MR. SIESS: This one had no thickened wall?
4 MR. HORSCHEL: Right. So a liner -- let me 5 go back to that last.
6 MR. SIESS: It's a steel frame, essentially 7 the same around both edges?
8 MR. HORSCHEL: The primary reinforcing is the 9 same boss around --
10
( MR. SIESS: By reinforcement, you mean the V
11 structural frame?
12 MR. HORSCHEL: Reinforcing steel.
13 MR. SIESS: No. I'm talking about the 14
(~')
v structural frame; the hatch is a steel insert, isn't it?
15 MR. HORSCHEL: Yes.
16 MR. SIESS: That is identical to the tube?
17 MR. HORSCHEL: There's differences between es 18 the two just because the one had an inboard hatch cover and
(
)
19 an outboard hatch cover. It has to be thickened for the 20 steel. The nominal thickness where it actually penetrates 21 the concreto as it goes through the wall is, I believe, the 22 same thickness.
23 Here you can see the insert plate around Equipment 24 Hatch A. This is in the plane of the cylinder wall, as is 25 this (indicating). You have a direct loading right thero l
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and you can transfer more load into it. With the other one, 8 2 where it's thick in both inward and outward, you have that 3
tapered section that you have to go through, which makes it 4
so much softer and much more difficult to get the O ring 5 into that sleeve through the liner.
6 Also, in code, you can't allow the liner to take 7 the radial load on the sleeve. You have to have a thickened 8 ring behind that. This hatch, because we only had the one 9 cover, has one collar around it and you can't see the 10 (cough). The other equipment hatch has two collars, which
()
LJ 11 also makes it stiffer.
12 MR. SIESS: Which one oval, the one with the 13 single seal?
(~1 14 MR. HORSCHEL: The one with the single l L j' 15 equipment hatch cover.
16 MR. SIESS: Of course, the one with the 17 double seal has got the thick wall, doesn't it? Which one g~, 18 has the thickened wall?
!'~'!
19 MR. HORSCHEL: Both of them have thickened 20 walls. One goes entirely to the outside of; one is centered 21 in the wall and goes both inward and outwward.
22 MR. SIESS: But the thickness is the same?
23 MR. HORSCHEL: Approximately, yes.
24 MR. SIESS: And the reinforement is the same 25 in the concrete?
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I MR. HORSCHEL: The primary reinforcing is the 8 2 same. This local reinforcing defines your -- the boss base.
3 MR. SIESS: Now, there is a steel insert in 4
there.
5 MR. HORSCHEL: The sleeve itself. Is that 6
what you're talking about?
7 MR. SIESS: That was the same?
8 MR. HORSCHEL: The sleeve is slightly 9
different because of the equipment hatch, sealing surfaces 10
/3 and -- l V 11 MR. SIESS: Is there any chance that the 12 steel with the collar was stiffer than one of the other?
13 MR. HORSCHEL: Randy, did you want to make a 14 comment?
(~)
15 MR. WEATHERBY: You said that the thickness 16 was the same. Were you talking about the two bosses 17 together on Equipment Hatch B7 18 MR. SIESS: While I'm thinking about the 19 piece of steel, the steel cylinder constitutes the hatch.
20 And on one end of that is a flange to which you attach a 21 cover. And that flange is what elongates and what ovals.
22 Right?
23 MR. HORSCHEL: Right. The sleeve itself.
24 MR. SIESS: Now, it ovals because it's got 25 more load on it in this direction and that direction; but p ___._. _
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l that flange physically, is it the same stiffness and strength of the two hatches. If I make that flange stiff 3
enough, it doesn't make any difference what load I put on 4
it, it's not going to oval.
5 MR. HORSCHEL: They are approximately the 6
same.
7 MR. SIESS: Okay.
8 MR. WARD: Well, let's see, would you 9
conclude that one of these design styles is superior to the 10
/~') other then, and I guess B is superior to A, or at least as V
far as resisting this high pressure?
12 MR. HORSCHEL: If you're worried about 13 ovalization, I would say that B is superior just because you 14
) have that transition region from the cylinder plane back to 15 the inside base of the boss.
16 MR. WARD: Yeah. .
17 MR. HORSCHEL: And that transition actually
, 18 makes that much softer so it's very difficult to get both
'w' 19 back into that sleeve.
20 MR. SIESS: The transition you're talking 21 about is, what, the thickening of the concrete?
22 MR. HORSCHEL: Well, it's the thickening of 23 the concrete but really what I'm referring to is that liner; 24 the liner is really loading the sleeve.
l 25 MR. SIESS: Robar is not attached to the l V lWNNmw REPORTING i l SERV 10E l a record of excellence
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4L_
I sleeve?
8 2 MR. HORSCHEL: That's right. The rebar is 3 not attached to the sleeve.
4 And the transition you meant was MR. SIESS:
5 where the liner bent.
6 MR. HORSCHEL: Right. And that's where you 7 had the two studs critical. As long as you -- see, those 8 studs are much more critical in that design as opposed to 9 the other.
'^ 10 MR. SIESS: If you really want to worry about 3
's _ /
11 designing containment for severe accidents, you could 12 probably design e containment sleeve that is a lot stiffer 13 than the ones we've designed for LOCA, could avoid some of 14 it.
~')
's 15 MR. WARD: It's just making the steel sleeve.
16 MR. SIESS: Make the steel sleeve stiffer; I 17 mean, to do it, make it easier if it's 14 to 20 feet down
.,fm 18 here.
N) 19 MR. HORSCHEL: But it's also conceivable if 20 you make the sleeve stiffer, thenyou can induce boss out 21 here in your liner.
22 MR. SIESS: Oh, yeah.
23 MR. HORSCHEL: So, I don't know if you want 24 us to comment on the design and how appropriate they are 25 for --
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I MR. SIESS: Ideally, you would like to be 8 2 able to reinforce a hole in there so that everything outside 3
the hole was the same as it was before.
4 MR. WARD: But didn't the B type design do 5
that better than the A type design?
6 MR. SIESS: It probably did, but then it did 7 other things that were worse; pulled out the studs.
8 MR. HORSCHEL: Let's jump over to B.
9 Here's our cylinder wall. This is what I found in the 10 e^S transition. Here's the interface of the boss.
w) II Here we had two small stud tears. As I pointed 12 out during the tour, this angle at first was very sharp, due 13 to the loading of the containment, it's actually curled and I
("i 14 it's now very rounded in here; and that's why I'm only J
15 giving ycu this mud flow back into your sleeve, it just 16 tends to soften that load.
17 MR. SIESS: Now, you told me that the
,- 18 prototype design where we made the square corner there.
?
\ ;
19 MR. HORSCHEL: Yes. Stone & Webster, I 20 believe generally uses the square right hand junction. We 21 were worried about placing the concrete underneath it, 22 especially at the top area and didn't have the access to use 23 in a full size containment, so we actually tapered this.
24 Here's one of those stud (inaudible) Equipment 25 Hatch B in that transition ring. You can see that this is a l
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42 _
I different type of failure than we experienced in other 8 2 areas. There is a direct (inaudible) to a shear type 3 loading on the liner.
4 MR. EBERSOLE: Would you kind of draw a 5
general overall conclusion that the studs do more damage 6
than they do good from this experience?
7 MR. SIESS: You can't conclude that. We know 8
what damage they do, but we don't know what good they will 9 do.
10
/; MR. HORSCHEL: They are there for a thermal 11 purposes.
12 MR. SIESS: I know they're there for thermal 13 reasons.
14
- MR. HORSCHEL
- And if you look at the
._/
15 magnitude of pressure during this testing, this 3.15 times 16 the design pressure, if you take care of this, are you sure 17 something else isn't going to happen at 3.16.
, f- 18 MR. SIESS: Or 3.14.
l (_/ 19 MR. EBERSOLE: Would buckling be all that 20 damaging? Would buckling cause leaks?
l 21 MR. HORSCHEL: Due to a large --
22 MR. BENDER: Well, I imagine you would want 23 to have some type of controlled information and that's what l 24 the studs do.
25 MR. EBERSOLE: In the buckling mode, but you
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I could do it in other ways. You could even fold it.
8 2 MR. BENDER: There are lots of ways to skin a 3
cat, but this is the way they chose to get it. A better 4
question is --
5 MR. SIESS: Jesse, we have some experience 6
with buckling. Ke have some actual experience with 7 buckling. Indian Point feedwater line failure, it occurred 8 right at the face of the inside wall of the containment 9 through 180 degree through-wall crack and it sprayed hot 10 feedwater -- and I don't know how hot the feedwater is -- up Q,)
11 the wall above the pipe. And it buckled out a section of 12 liner, as I recall, about 10 to 12 feet wide, circumquenchly 13 and about 30 feet vertically.
14 It pulled the liner away from the angles. It f}
15 didn't have studs, but there were circumquenchal angles.
16 Actually sheared off -- broke the weld, left the angles 17 embedded in the concrete and broke the welds. It did not 7s 18 cause a leak. They were cracks formed where the channels i
()
l 19 were welded, the vertical channels, at the edge of the 20 buckle, but they weren't through wall, but that might have 21 been pure chance. So if you had nothing, you could probably 22 buckle a pretty good section in and maybe not rupture the 23 liner. But then, I don't know what I would do if I had 24 140 psi acting at the same time and a few other things.
25 MR. HORSCHEL: It is one conclusion that we l ; -__ --
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I haven't tested or the ankor system in any containment is 8 2 going to play an important part in the liner integrity.
3 MR. SIESS: What is __
4 MR. HORSCHEL: All capacity is really 5
unknown. It depends on what type of situation you have.
6 Here we have some studs. Does a full size stud behave the 7 same way? They also have angle sections attached to it.
8 But do those engage the same way.
9 MR. EBERSOLE: In the ice condensor like at
,e to 3 Sequoyah, that was a major problem.
\ )
11 MR. SIESS: That's just a steel containment.
12 MR. EBERSOLE: I know, but --
13 MR. SIESS: We tested those two years ago; 14 I ') they acted differently.
15 MR. EBERSOLE: Yeah. We really haven't come 16 to a --
17 MR. SIESS: Got a better reason for putting a 7, 18 concrete shell around it?
( j 19 MR. BENDER: -- judgment yet as to whether 20 the steel is hydrocracked and is bad or good; all we've 21 established so far is --
2? MR. HORSCHEL: It's going to be important for 23 the liner. It's something that we feel -- you will see 24 later when you start talking about the analysis. But 25 something that you have to include in here now, whether it's l
l ,s U
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1 going to fail the liner or not, is going to depend nn any 8 2 particular situation that you're going to look at. Maybe 3 you'll have it all, maybe not. We need to learn more with 4
our ar.alysis and extrapolate with this model as with a full 5 size plant.
6 MR. BENDER: Are you, later on, going to try 7 to answer 6 few questions, like what were we trying to find 8
out and how we could use the results? Are you going to try 9 to answer those questions?
10 MR. HORSCHEL: Specifically, in this 11 presentation, no. If you want to ask questions .t any time 12 through here, I'll try and go through it; I'll try to sum it 13 up.
'~
/ 'T 14 MR. SIESS: Let's save those near the end of J
15 this, Miko.
16 MR. BENDER: I wasn't planning to depose him 17 now. I just asked whether he was going to be available.
s 18 MR. SIESS: They are going to get asked;
' ; )
19 whether they answer them or not, I don't know.
20 Dan, a lot of the earlier containments -- and I 21 can't remember how long they kept it up -- they always 22 welded leak channels on the back of the walds.
23 MR. HORSCHEL: Near the backup bars. Right?
24 Especially --
25 MR. SIESS: Every weld in the containment had f
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a channel welded on the concrete side of it for leak 8 2 testing. Not only did you have the weld in the liner, you 3
had two more welds from the channel welded on there. Is 4
that being done any more?
5 MR. HORSCHEL: I'm not familiar with it.
6 Since you're not making any containments any more, I guess, 7 they . . .
8 MR. SIESS: I know they were doing it for a 9
long time because the specs don't call for 100 percent leak
,r ' ; 10 testing of liner welds; it only calls for a 10 percent
't.)
H sampling, 2 percent sampling, I think. So they have these 12 leak channels; they could, you know, measure the leakage 13 through the welds by adding more welds. I never quite 14
{') understood it, but . ..
15 Okay. Go ahead.
16 MR. HORSCHEL: We considered about getting 17 those in this containment model. But we saw that same gm 18 problem and decided to go without.
i )
19 What we did do was 100 percent vacuum boxes. We 20 actually put a box on there tc pull a vacuum, after you soap 21 solution the weld.
22 MR. SIESS: Ycu did 100 percent weld test.
23 MR. HORSCHEL: We needed 100 percent vacuum 24 box.
25 There's only one representation of a personnel 1
o _ - -.
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airlock. We had a monitor on u outside over here. You 8 2 can actually see the studs marked in this figure. On the ,
3 opposite side is a close up view of that tear. This is what 4
we found on our post test inspection. We do have a gage 5 located right here.
6 MR. SIESS: You're sure you don't have one 7 under the gage?
8 MR. HORSCHEL: I'll get to that one.
9 Here again, you can kind'of see the base of the 10 stu6.
{-} 11 MR. SIESS: I always figured strain gages 12 were reinforcements.
13 MR. EBERSOLE: Isn't that a fundamental; you
() 14 can't measure anything?
15 MR. HORSCHEL: Here post testing you can see 16 the effects of the basemat evidence from my work map. As I 17 said before, that's probably more visable in our video film t
18 than it is in this photo, but at least you can see that it 19 did happen. It was a fairly uniform around the conteinment.
l 20 Obviously, somc variation in the amount, but it was still 21 fairly even, about three-eigths of an inch.
! 22 Let's get to the one gage that we did have over a i
23 stud. And I also want to point out that this is where --
24 our structural integrity test is close to the high pressure 25 test. We have a strip gage, which is a group of ten gauges O _
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at*c ached to a common backing. And this case, we only wired 2
seven of those ten gages which you could actually see the 3
strain concentration due to the stud. In effect, in the 4
SIT, where we only went up to about 53 psi gage, you can see 5 that we had strains on the order of .55 percent.
6 MR. SIESS: Each one of these is a different 7' gage.
8 MR. HORSCHEL: Yes. I --
9- MR. SIESS: And four of them are closer to 10 the stud, and the other three are out further.
(-}
v Il MR. HORSCHEL: Yes. The total length of this 12 gage I believe is like one and an eighth inch long, very, 13 very closely --
14 What was the spacing in the MR. SIESS:
15 strip.
16 MR. HORSChEL: Ten gages on a strip; total 17 strip length 1s about an inch and an eighth, t 18 MR. SIESS: I mean, were they like this or 19 like this (indicating)?
20 MR. HORSCHEL: In this case, they're all 21 horizontal and they're measured in a hoop direction sprains.
22 MR. SIES3: Yeah, but are they in series or 23 parallel, I guess that's what . . .
24 MR. HORSCHEL: It's in a series.
25 MR. SIESS: The series are getting --
O ram 9amiw REPORTING SERVICE a iecord of excellence
I MR. HORSCHEL:
8 The strip is in the horizontal 2
direction an'd each gage on the strip is measured 3
horizontally.
4 MR. SIESS: Okay. I see. And what's the 5 yield strain of that material? l 6
MR. HORSCHEL: Randy, you're going to have to 7 answer that.
8 MR. WEATHERBY: It's going to be around 9 .2 percent or so.
10
,_ MR. SIESS: So the liner runs that high?
11 MR. WEATHERBY: Let's see, it will be about 12 50.2 KSI over'--
13 MR. SIESS: Leave that up just a minute.
14 MR. EBERSOLE: These all show permanent l 15 views.
16 MR. HORSCHEL: Yes. That's my next point.
17 MR. SIESS: That was a tremer.dous historesis.
18 MR. HORSCHEL: We continued on in the high 19 pressure test. This is the same strip. Of course, you 20 only -- in my era, I only got six of the seven gages 21 (inaudible).
i 22 But we zeroed that. Any plastic strain that was 23 there was zeroed in the audit at the beginning of the test.
24 You can see that we probably had about 25 percent strain, 25 plastic set. That was zerced. And then when we conducted O memw REPORTlNG SERVlOE a arcord ofexcellence - . -
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the high pressure test, we started from zero and continued 8 2 on and had some substantial strains, over three and a half 3
percent.
4 Have we got that slide?
MR. SIESS:
5 MR. HORSCHEL: Yes, you should have both of.
6 these -- the back of'the packet and it belongs to you.
7 MR. WARD: I think it's in this other --
8 MR. HORSCHEL: It's in both of the reports.
9 MR. SIESS: Oh, it's in one of the reports.
10 Okay.
11 MR. HORSCHEL: It's also in the viewgraphs.
12 MR. SIESS: I just couldn't read the scale, 13 that's why I was asking. That's all right. Just put the 14 last one up for a minute, will you?
15 MR. HORSCHEL: Just the last one.
16 MR. SIESS: You got up to about three or 17 4 percent then. What's the -- I can't read the arc real --
18 pressure scale, 30, 60 . ..
O 19 MR. HORSCHEL: Yeah, 30, 60, 90, 120, 20 Pressure is 145 and they said wo lost some pressure during 21 that last leak measurement. That brought us up to about 22 140. We actually did another scan. You see we had some 23 significant straining; we were actually trying to maintain 24 pressure and were actually losing it slightly.
25 MR. SIESS: Which of those correspond to the O rmawEur REPORTING SERVlOE a Ircord of excellence
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' I four that were very high in the previous plot?
2 MR. HORSCHEL: I guess I would have to'look 3
at the individual plots. I do have them listed but I don't-4 know them off the top of my head.
5 MR. SIESS: So there is less difference 6
here --
7 MR. HORSCHEL: We'v3 got a strained 8
difference here.
9 MR. SIESS: Huh?
10 l
{} "
MR. HURSCHEL: There is 1 percent difference between the first and last.
12 MR. SIESS: Yeah, but there was a 10-to-1 13 difference on the others. Five, six-to-ono difference on l
() 14 15 those.
MR. HORSCHEL: Okay, i
16 MR. SIESS: The three on the left are a 17 fraction of the four on the right. As you moved away from 18 the stud, it really went down. But on the other figure that O. 19 is --
20 MR. HORSCHEL: That's fairly consistent,
! 21 which means you're really loading your stud and you probably 22 have some classic defemation in your stud.
i 23 MR. CLAUSE: I guess that's kind of typical.
24 What you see in an analysis, though is that drain 25 concentration associated with discontinuity like the studs i
l
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tend to be higher when you're elastic, or they're low (inaudible). As he strains, enough power strains the 3 concentrations actually decreases on a relative basis.
4 MR. SIESS: What kind of stress / strain curve 5 do you have for the liner? Have you got a plastic region on 6
it?
7 MR. WEATHERBY: Yes, it does.
8 When does it start strain MR. SIESS:
9 augmented?
10
/'") MR. NEATHERBY: I guess I would have to look
's _/
11 at that. I don't remember off the top of my head.
12 MR. SIESS: Your old model steel went outt 13 about one and a half, 2 percent.
Iu-') 14 MR. WEATHERBY: I believe that's around 1.7; 15 1.8 percent.
16 MR. SIESS: Thank you.
17 So you were one and a half -- one, one and a half
,~~
, 18 percent in the strain hardening here. You're out beyond i
19 that plastic.
20 Okay. Thank you.
m 21 MR. HORSCHEL: And finally, I want to discuss 22 the future options we have of the model.
23 First, of course, is the nondestructive test of 24 the containment model. We have several things that we will 25 be doing. Vacuum boxing some of the liner sections that U,3 maNNum REFORTlNG SERV 10E a reconi of excellence
54 1
were in critical areas and including some down, for example, 8 2
~
in the basemat showing wall region, it's under water. It's i
3 not showing visual signs of the stress, which we like to 4 check on. -
S We also will possibly do some x-raying of critical 6 areas, specifically in the areas of major tear. We'll 7 probably end up removing concrete in that area just to 8 understand more of what happened there, how much the 9 delamination was, and some of the dislocation motions in to there just to better understand what happened.
11 MR. SHEWMON: X-ray is to radiography for 12 loss of density or what do you mean X-ray? ;
13 MR. HORSCHEL: Just to see the placement of
(} 14 rebars, how things move, see if we can determine any 15 slippage, things such as that.
16 MR. SIESS: When you remove the concreto, and 17 particularly, you're worried about the delamination, do you 18 expect to mark it in any way before you remove it?
19 MR. HORSCHEL: It's something that we need to 20 talk about before we do it. And that's why we haven't --
21 MR. SIESS: I've had that problem of having 22 cracks and didn't know whether they went this way or this k l
23 way in a particular thing. And we used something that would 24 be very crude compared to what Sandia can think of, I'm j 25 sure. I went out and got a gallon of wood stain and poured O mmm mt REPORTING SERVlOE i
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I it in the crack. And when I picked the thing up, I could 8 2 tell where the cracks were. I'm sure you could find a 3
better system of injecting some sort of a dye.
4 Your transverse cracks are likely to be, you know, 5 just straight through the wall. If you look at that 6
delamination, it would be worthwhile to try to inject some 7 sort of a dye that -- because you probably pick up 8
delamination by just the concrete coming apart? But you are 9
thinking about some way of looking at some of this stuff?
10 MR. HORSCHEL: We will be, yes. We 11 appreciate your input into that and want as many opinions as 12 we can get before we commit ourselves. Once you start 13 cutting it apart, that's it. You want to document it well
() 14 15 before --
MR. SIESS: Some people do worry about this ,
16 plate-out business. I'm just not sure the model was 17 designed for that and how good it would be. But one 18 possibility would be to inject something from the inside
,' 19 through the crack to see what path it took, although liquid 20 and a gas wouldn't necessarily take the same path, i
21 MR. WARD: Well, that's his air -- he's got 22 that down there is very slow --
23 MR. HORSCHEL: We also wanted to measure the 24 thickness of the liner in those areas to make sure 25 (inaudible) or do you want how much flaw that was just not l
O inm w m REPORTING
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8 2 containment model.
3 At this point, after we conclude nondestructive 8
test, we have a couple of paths that we could tale, t which
~
5 are some I've mentioned exclusively.
6 First, the sectioning of the containment model.
7 We can actually inspect these areas with greater frequency 8
and look at some of these and see if we can learn more about 9
what happened during this test or, again, we can retest the 10 containmer.t model and have several optione there.
11 The first one that comes to mind, of course, is, 12 in carrying this test out with the use of a bladder. We can r
13 also continue on with doing something with the liner repair i 14 to see if we can develop some other type of repair.
(]) ,
15 We also have dynamic options, both' external 16 explosions and external explosions, and also things such as 17 terrorist attack and small munitions, and also aerosol 18 testing of the containment.
O 19 Right now, we're probably leaning more towards l 20 this area, but we are keeping an open mind in trying to 21 determine what will be the best route with the dollars that j 22 we have in the interest of the NRC.
23 MR. SIESS: Let me raise a couple of comments 24 on these possibilities, j
! 25 MR. HORSCHEL: Certainly, r l ,
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I MR. SIESS: The bladder would be interesting, 8 2 I think, because you find out when your large hatch is 3
ovaled enough, and you might manage to get it up to a 4
knuckle failure.
5 Why the repair? I can't see any advantage.
6 You've got enough tears in that liner that you repair these 7 and yor.'ll just be 2 psi up and get some more. That's just 8 my feeling.
9 The dynamic would be interesting except that 10 unless you repair the liner, you've already got the cracks rN i 11 started and you would have a real question about that. And 12 oven if you repaired it, I'm not sure, although that would 13 be interesting.
g
,j
) 14 What's the external like?
15 MR. HORSCHEL: Just an external blast to see 16 how the container behaves.
17 MR. SIESS: The only plant we ever worried 73 18 about -- let's see. We worried about that on two plants, if
! l 19 I'm not mistaken. We worry a lot more about missiles.
20 MR. EBERSOLE: If you put a bladder in it and 21 you're saying retesting so the bladder will treck the 22 defamation of the concrete, won't you eventually then 23 catastrophically fail the concrete?
24 MR. SIESS: I could use water.
25 MR. HORSCHEL: And we could tear the bladder o _ _.
U m a19 19 m liEPORTllM SERV 1CE a nYoni of' excellence
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l and lose whatever pressuring of the water.
8 2 MR. SIESS: You could use water like they 3
did --
MR. EBERSOLE: I'm talking about if you used 5
air. It would lead to a catastrophic --
6 MR. HORSCHEL: Certainly you would expect 7 some type of rebar failure. And what that led to, it was 8
really hard to speculate that. It's hard to conceive of 9
anything happening like with our steel model test where 10 q
V pieces actually came off of the containment model.
11 Keep in mind they actually severe a chunk of this 12 concrete out -- a large chunk. They're serving at least 13 eight layers of reinforcing bars all around the whole 14 mercury of that chalk.
, 15 MR. EBERSOLE: Well, it would search and find 16 a weak place, though, wouldn't it?
17 MR. SIESS: If you test with the bladder, 18 I'll take bets on what fails -- the bladder.
l O 19 MR. EBERSOLE: The bladder?
20 MR. MICHELSON: Well, it seems to me before
! 21 you do anything -- begin to think about what kind of i 22 accidents go with this kind of overpressurization. And it 23 seems to me the only kind that can go with them are those 24 that involved very high temperature gases. The core has to 25 heat up a lot to generate the pressure.
O m e nt REPORTlNG SERVlOE l a Ircobri ofexcelleibcc
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I MR. HORSCHEL: Very high temperatures in the w 2 large part of the annular in the order of 360 degrees 3 Fahrenhe'it. Is that correct?
4 MR. MICHELSON: Well, I suppose it's of that 5 order. I've not really tried to postulate the number.
6 MR. SIESS: Okay.
7 MR. MICHELSON: But, whatever it is, I think 8 that that particular accident is one which could lead you to 9 want to know certain kinds of things.
10 First of all, is the pressure self-limiting 11 because of the crack? Does it leak out fast enough, provide 12 some kind of plateau.
13 And secondly, I think you would want to think 14 again about those temperatures as to how they might affect 15 that gaskets or the O rings or whatever it is you've got in 16 there. There's another distortion here now. So maybe only 17 one of the O rings is affected, and it's the inner one, I 18 guess.
O 19 So I think without trying to make any judgments 20 about what's important, that you ought to try to correlate 21 the results with accident phenomena.
22 MR. SIESS: Well, if you're talking about 23 slowing the pressure, severe accident, you know, builds up 24 over a period of several days. I remember the figures -- I 25 thought you fellows had made some calculations earlier in O mutwnr REPORTING SERVlOE a arcord ofcxcellence
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1 the game. I remember for a full-sized containment, a three-8 2 inch diameter opening was self-limiting in a slow 3 overpressure case. And'for this containment, that's, you 4
know, 1/36th of that, three-inch -- 12-inch diameter. So I 5 don't think there's any question about it being self-6 limiting.
7- MR. HORSCHEL: I guess the most recent stuff 8
I heard on self-limiting holes to limit the pressure in the 9
containment, is varied and it really depends on the 10 accident. I've heard some things quoted where the 11 full-sized containment of having holes in there as far as 12 seven-foot squares or seven square feet. I can't remember. I 13 MR. SIESS: No. That's their assumption l 1
14
()
%J for -- that's just a pure flat assumption for what it l 15 constitutes fully. '
16 MR. CLAUSS: Seven square feet corrosponds to 17 rupture and (inaudible). It's more on the order of 10 ,
18 square inches (inaudible) self-limiting for a slow 19 pressurization.
20 MR. SIESS: And this is nothing but decay 21 heat and no heat removal? ,
22 If there's core concrete interaction would be 23 generating more heat, I guess. It's small for this thing. }
24 MR. EBERSOLE: Have you-all done any testing i 25 on the electrical penetrations?
O _
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8 2 MR. HORSCHEL: And in other divisions of 3
Sandia, yes.
4 MR. EBERSOLE: Well, long before you get --
5 as Mike says, the pressure is due to temperature, and the 6
temperature is going to carry away the guts of the 7 penetrations because there has been a compromising 8 (inaudible) that's unsuitable, I think.
9 MR. SIESS: Yes, and we're going to hear 10
~j about that later.
O 11 MR. EBERSOLE: You know Charlie Wallis?
12 MR. SIESS: Yes.
13 l MR. EBERSOLE: Okay.
I, 14 MR. SIESS: Well, they've got tests on that.
15 MR. HORSCHEL: I guess we really don't have 16 anything on electrical penetration.
17 MR. CLAUSS: Well, we don't have anything to 18 present so maybe it's appropriate to attribute common
~
19 knowledge (inaudible). What we found in our EPA testing is 20 that because the length of the assemblies is so long that 21 significant aftergrading is from the inside to the outside.
22 You're right, the inside seals do degrade, but there's a 23 small enough path that you don't even get that much leakage 24 past the inner seals.
25 In any event, regardless of what happens to the
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inner seals, the outer sea'ts never see the full temperature 8 2 of the accident. In fact, nothing even close to it. And 3
those outer seals prevent any leakage to the environment 4
through --
5 MR. EBERSOLE: They never do heat up that 6 much?
7 MR. CLAUSS: No.
8 MR. HORSCHEL: And the only caveat that I 1 9 would like to point out here is that we tested three types 10 of electrical penetrations. And I guess there's many more 11 out there. Some of them were actually built in the fields.
12 But we don't have access to all of them. We're going to 13 have to look at each specific one. But the three that we 14 tested, what they said is correct.
[}
15 MR. SIESS: But most of them do have an inner 16 and outer seal and there is some temperature difference. ,
17 Now, the glass ones didn't give any problem at all.
1 18 Look, have you made any analyses yet with
)
19 temperature --
20 MR. HORSCHEL: For a different type of 21 things, yes, we have. We've looked at, for example, large
{ 22 drywell heads and --
l 23 MR. SIESS: No. I mean, for the containment.
24 MR. CLAUSS: For the reinforced concrete, no, i
l 25 MR. SIESS: Temperature should help. It puts O manNni*
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I the liner in compression. Does it do anything bad? Well, 8 2 this program that came in ought to help. Right?
3 MR. CLAUSS: I think it's really hard to say 4
that without giving some analysis because there is a 5 competing phenomena going on. You're right, thermal 6
expansion, differential thermal expansion puts the liner 7 into compression. But at the same time, the elevated >
8 '
temperatures reduce yield strength for that liner.
9 MR. SIESS: How much does it reduce the 400?
10 MR. CLAUSS: About 20 percent I would think.
Il MR. HORSCHEL: But does activity also 12 increase? ,
13 MR. CLAUSS: That's what I said.
(J 14 MR. SIESS: That is the one thing that's i 15 missing from this test. The severe accident which will 16 produce 145 psi is also going to produce 300, 400 degree 17 Fahrenheit temperature. And that's a question somebody will 18 eventually ask. And at least for this type of failure,
(
j 19 that's one advantage of testing the thing and knowing how it 20 fails. Now you can go back and analyze whether the
~
21 effective temperature is good or bad.
22 MR. CLAUSS: And that's what we intend to do.
23 I mean, the long-range plan is first to finish our 24 comparisons with this test and convince ourselves that we 25 can do a good job of analyzing for static pressure alone.
O -
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1 And then analytically we'll go back and add temperature. '
8 2 Well, if there seems to be a lot of effects on the 3
order of confidence, then we may try to design separate 4
effects tests to validate our model that includes thermal 5
(inaudible).
6 Before you go too much further, I would just like 7 to make one comment on the testing with the bladder.
8 We did do a quick analysis to see what the 9
capacity might be if we test with the bladder. You have to 10 keep in mind that the liner has significant tears in it.
11 And before the test, we had calculated that the ultimate 12 capacity where you get rebar failure in the range of 180 to 13 190 psig. The liner, however, is a significant contribution 14 to the overall strength in the order of 15 to 20 percent.
15 MR. SIESS: 15 to 207 16 MR. CLAUSS: And if you just do a simple 17 back-of-the-envelope type calculation, take the liner 18 essentially out of the ultimate strength, you're right down
- 0 19 around 145, 150 for the failure pressure. So you're not 20 going to get much further out of the pressure range that you 21 retest the bladders. The only advantage would be that you 22 might get some information on other failure or, i.e.,
23 catastrophic failure.
24 MR. SIESS: Yeah.
25 MR. WARD: Can you describe real quickly what 2
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1 retesting with the bladder means. It's on your checknotes, 8 2 but I don't know what it means.
3 MR. SIESS: No, I don't know any more than 4
you do.
5 MR. HORSCHEL: Instead of using a liner as a 6
pressure gird, we have to put some type of rubber membrane 7 on the inside and use that as our pressure barrier. Keep in 8
mind in our current configuration that's quite difficult to 9 do. It's not a small task.
10
(~'
\
MR. SIESS: That's why I said, I bot the
~
11 bladder fails.
12 MR. HORSCHEL: We'll probably have some 13 (inaudible) in this place. We have all our lead wires
~'s 14 running through, which you would also have to run through (G
15 that bladder somehow. So it's a big complex thing.
16 MR. SIESS: Well, Murray did that at Alberta.
17 You're familiar those tests?
, 18 MR. HORSCHEL: Yas.
~
19 MR. SIESS: I'm not sure what his details 20 were.
21 MR. HORSCHEL: I don't think they had 22 anything on them at all except the bladder and the water.
23 MR. SIESS: Yeah, I don't think he had any 24 penetrations, you know. He got it to fail just beautiful.
25 Water poured out everywhere.
c'1 U 1aaN N1a m liEPoliTlNG SEliVlCE a n' cold of' excellence
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1 MR. HORSCHEL: And also, one point about the 2
dynamic testing is, our current data acquisition system is 3
set up for a static test so that would necessitate redoing 4
our data acquisition system for a dynamic test, which would i 5 also be -- have a significant cost attached to it.
6 Continuing on wit.4 separate effects tests, the 7 first one here is equipment hatch leakage. We figure we 8 could actually use some stuff on the containment model with 9 those two equipment hatch covers. We can more or less seal
.i 10 one off and see if we can get that unseating of the 11 pressure, unseating equipment hatch, what type of leakage we 12 would get through there with certain displacements and 13 things such as that. They're fairly inexpensive tests.
() 14 MR. SIESS: How close were you to complete l 15 unseating of that (inaudible).
16 MR. HORSCHEL: Again, we had to use some 17 opinion in that. My opinion, looking at what we did with 18 leak rate tests after the conclusion of the test and what we
( 19 measured throughout the test, I suspect that we did have 20 some unseating of Equipment Hatch B with some very slight 21 leakage there that does jibe with what we actually 22 calculated. We would see those at --
23 Mh. CLAUSS: I guess we definitely had an i 24 unseating, if you mean by unseating, separation of the 25 metal-sealing surfaces. There's no question about that.
O 1mna-REPORTING .
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1 What the question is, whether or not we had enough unseating 8 2 that you exceeded the springback capability of the seal and 3 thus produced leakage.
4 MR. SIESS: Now, that's scaled properly?
5 MR. HORSCHEL: Properly is hard to say 6 because --
7 MR. CLAUSS: Geometrically scaled.
8 MR. HORSCHEL: Geometrically scaled 9 accurately describes --
10 MR. SIESS: Whether they're proper or not, 3
i 11 you know, that's a difficult thing to scale.
12 MR. HORSCHEL: Yeah, we never felt we could 13 really scale the leak rate coming from the containment.
~
(i 14 Obviously, some other candidates for separate LJ 15 effects tests that we've listed here is an insert plate in 16 the liner section, similar to what we had in our 17 Containment, kind of looking at the strain concentration
) 18 there and what effects that had. We could continue on with j
") 19 this for concrete and studs and see how those things 20 interact, see if we can actually duplicate the type of tears 21 that we saw on our containment.
22 Also the knuckle region in our containment is 23 still of some interest, h, want to know why we didn't get a 24 shear failure or better understand what happened in this 25 region.
p) _ _ _ _ _ _ _ _ _ _ _ _ _ _
t 1;1alq1glam lila120liTlNG SEliVlCE a n' coni of' excellence
68 _
l Also, we saw some punching shear of the bosses, 8 2 some dislocation motion there. Those are also candidates 3
for separate effects test.
4 And lastly, as you saw out on the site, we have 5
some reinforced concrete panels that are typical of the 6
model that we would like to test to see if panel testing is 7 a good idea to extrapolate the full-sized containments and 8
actually a pressure vessel as opposed to a flat panel.
9 MR. SIESS: This business with the insert 10
~x plate, I would think that if it was just a question of the (d
11 stresses and strains, you would find that element of 12 analysis ought to be pretty darn good for that. It may be a 13 simple test to verify it. But the real problem is going to 14
(~')
v be handling what the stud does to the material proporties 15 and local enforces put on there by the stud which, I think, 16 is completely independent of the insert plate. The insert 17 plate might have changed the stress field in their. But the g3 I
18 failure was local to that stud for that stress field.
\
19 MR. HORSCHEL: Okay, 20 MR. SIESS: If there hadn't been studs in 21 there, do you think it would have -- what do you think would 22 have happened to this thing with no studs?
23 MR. HORSCHEL: I dor'* .hink we would have 24 seen those tears there. But I also snink that you you need
! 25 that insert plate. It's a combination of things. It'c not O
~
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l REFORTlNG l SERVlCE a reconi ofixcellence
69 -
I one or the other. I think you need that insert plate in the 8 2 studs there.
3 MR. CLAUSS: I think Randy will show some 4
analysis of which we essentially look at the effect of the 5
insert plate. And ths effect of the insert plate is to 6
cause a very high slip area immediately adjacent to that 7 insert plate.
8 MR. SIESS: By "slip area," you mean relative 9
movement to (inaudible) concrete?
10
(~3 MR. CLAUSS: You bet. And the stud, of V M course, tries to constrain that movement. And that is what 12 develops.
13 MR. SIESS: I suspect that no matter how you 14
()
v do it, the stud gets (inaudible), period. The stud cannot 15 take that slip without yielding.
16 MR. CLAUSS: But the point is, there is no 17 slip without an insert plate or something that's been
,- 18 changed -- to move away from the uniform (inaudible).
N )3
'~
19 MR. SIESS: And once that stud has got a load 20 on it of a certain amount, that's all that you can put into 21 the plate. By shear and bending and the load remedy, the 22 shear you can put on that stud before it (inaudible) the 23 concrete depending on, take it are both finite.
24 Thank you, Dan. That was a very good 25 presentation.
,m i _ __ _ ._ _ . . _ _ _ .
L) man 10am REF0liTlNG SEliVlCE a Irconi of' excellence
70 ,
I MR. HORSCHEL: Thank you.
8 2 MR. COSTELLO: To put things in the 3
perspective of the four bullets in number 3, in the interest 4
of expedienc, Dan.
5 MR. SIESS: Aro we through with No. 27 6
MR. COSTELLO: We went through No. 2. I'm 7 sorry, sir.
8 MR. SIESS: We haven't heard anything about 9
the British yet.
10
'S MR. COSTELLO: Okay. If you want to look at U 11 this agenda --
12 MR. SIESS: Yeah, but I want to know where we 13 are on that agenda.
14 MR. COSTELLO: Okay. On this agenda, sir,
( })
15 we're still talking about comparison to predictions.
16 MR. SIESS: Okay. We're still in that --
l 17
~
we're in the second bullet. I just --
3 18 MR. COSTELLO: And we have two presentations 19 on the predictions versus populations.
20 The first one will be by Dave Clauss, who has 21 organized and orchestrated a very interesting undertaking of 22 which there are 10 organizations who made the blind protest 23 predictions which were published in the NUREG (inaudible) on 24 that part to offer speculations as to the --
l 25 MR. SIESS: Let me remind -- I should mention U,
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I that the Subcommittee numbers received copies of that NUREG.
8 2 I doubt if anybody has read it. It's a little bit thick.
3 But maybe they looked at the Executive Summary.
4 MR. COSTELLO: It has predictions. And 5
again, the predictors met here in Albuquerque in November, 6
had an initial meeting and an initial retrospective. They 7
are then going to go back and do a little further work and 8
have a final comparison and assessment of fidelity of 9
predictive methods, which will be presented on or about the
', 10 3
same time as our workshop in June, ej 11 MR. SIESS: Now, what are they supposed to do 12 next if they're going -- obviously, they can all calculate 13 now at what pressure failed. We know that.
() 14 Are they going to now try to explain why?
15 MR. COSTELLO: Yes, and they're going to 10 concentrate -- Dave will talk about this. But essentially, 17 they're going to concentrate on what they felt were the
,-,s 18 shortcomings of their modeling on what they would have to
! )
19 approve to get there.
20 MR. SIESS: Why they were wrong?
21 MR. COSTELLO: Yes, essentially. And Dave 22 will talk about that and will be followed by a presentation 23 from Randy Weatherby, who had done some scoping claculations 24 using different kinds of concrete modeling techniques.
25 Dave Clauss will be first. Mr. Clauss?
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MR. SIESS: You know, what I found !
, w 2 fascinating was how much difference there was of prediction 3 of displacement. ;
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7 MR. CLAUSS: Okay. I'm David Clauss for i 8 Sandia. I'm going to be talking about the group efforts, if f
9 you will, on the analysis of the 1:6 scale model. And I f i
10 really wasn't planning on going into great dotail. I just 11 wanted to give you a feel for what the activity was there I 12 and what the future plans are. If you want more detail, I 13 you'll just have to ask the questions and I'll try to answer j.
14 them the best I can.
15 First of all, the objectives of the analysis. One 16 of the first objectives in doing pre-test analysis is to gat 17 some insight that can be used both on the instrumentation f
i 18 and conducting the test. And I guess I feel like we were
' O 19 pretty successful in that, especially given some of the 20 things that we captured during the test with
, 21 instrumentation. We had a lot of strain gages in and around l 22 the penetrations where actually it would capture a lot of '
23 the high-stream concentrations.
24 Then the second objective, of course, is that did
! i l
25 they have a blind prediction that you can use to equivalent l
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1 your analysis methods.
8 2 Okay. And then after the test, what we wanted to 3 do with the analysis. The first thing, of course, is to 4
understand the limits taken that control the model failure.
5 And that's something that we're really just getting into 6 right now, as well as the other groups. So it's really not 7 a final conclusion now.
8 The second objective is to recommend additional 9 tests, to investigate other potential limit states in the 10 (3) containments. For instance, we would lil:e to look into
\
11 shear failures. That is something that we still don't have 12 a lot of confidence in predicting. It wasn't a mental state 13 that we realized in the mode), but it's certainly a
(')
x_-
14 possibility in the actual containment under actual severe 15 accident loads.
16 And then the ultimate objective, as I think Dan 17 has already pointed out, is to propose a comprehensive
,- 18 approach that can be used to evaluate performance of i
J l
19 containments in the event of a severe accident.
20 Okay. I really wasn't sure exactly how familiar 21 you all were with this effort that we have and who was 22 participating. I just wanted to give you an idea of who is 23 involved. And it is a fairly diverse group representing 24 people anywhere from utilities to regu]ators to national l 2s laboratories, and pure research organizations.
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I In the U.S., there were four groups, three 8 2 national labs, Brookhaven, Sandia, and Cargon National 3 Laboratories. EPRI also participated. The work for EPRI 4
was done by ANATECH.
5 In France, there was CEA participating; United 6
Kingdom, we had Nuclear Installations Inspector, central 7 electricity generating toward, and the safety and 8 reliability aspects. In France -- I said France earlier.
9 In Italy, we had the regulatory agency there, 10 ENEA. I'm never going to try to tell you what that stands
(~}
t/
11 for. It would take about five minutes.
12 In West Germany, there was GRS.
13 MR. SHEWMON: What's the SRD in the U.K.7
^
14 MR. CLAUSS: That's the Safety and (d'
15 Reliability Directorate.
16 MR. SIESS: They're a regulatory.
17 MR. SHEWMON: What's NII?
73 18 MR. CLAUSS: That's regulatory, isn't it?
~'
19 MR. SHEWMON: So what's the SRD7 20 MR. WARD: I think that's part of the UK AEA.
21 MR. CLAUSS: They're not a regulatory.
22 MR. SIESS: No, they're not. They're more 23 DOE.
24 MR. WARD: Sort of DOE or AIC.
25 MR. CLAUSS: I guess I should point out, too, o _ - _ - _ __
L) uvNNnm lie 120liTlNG SEliV10E a reconi of' excellence
15 7
1 that most of these groups -- in fact, all of them 8 2 essentially did this using their own instrumentation except 3 for Sandia and Brookhaven. They were funded through 4 agencies other than the NRC.
5 So essentially, it was on a voluntary basis. Our 6 only cost was that of supplying the materials to do the 7 analysis.
8 Some of the benefits of doing this, we got as 9 much -- instead of having just Sandia analyze the problem,,
g-) 10 they had 10 groups. And by doing that, you get a much C/
11 greater awareness of what the potential failure modes in the 12 containment are. And that gave us, I think, a better 13 ability to plan the tests.
14 It was a way of establishing uncertainty in
(^/}
w 15 pre-test predicions. You would take 10 people who are all 16 competent and you let them do analysis and they came up with 17 great answers. And that's a measure in a sense of the e- 18 uncertainty in the state-of-the-art capabilities.
(\)
Were they all -- I'm sure they 19 MR. SIESS:
20 were all experts with analysis. Were they all equally 21 expert in the behavior of reinforced concrete?
22 MR. CLAUSS: I would say that in the U.S. all 23 four groups definitely had a lot of experience in reinforced 25 concrete. France, the CEA group certainly has extensive 25 studies in that area.
o _ _ _ _ .__ _ -.
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I'm really not sure about all the British groups.
8 2 CEGB, I'm not sure. But we certainly have a lot of (cough) 3 reinforced concrete containments. But I'm not sure --
4 MR. HORSCHEL: One thing there, Dave. The 5
CEGB went with Taylor-Woodrow that has this type of 6 experience.
7 MR. SIESS: Well, Taylor-Woodrow has done 8 some testing. I'm not sure CEA has --
9 MR. COSTELLO: CEA has done some test on some 10 pre-test stresses.
11 MR. CLAUSS: Testing and analysis, yeah.
12 They have done a lot of work.
13 GRS was relatively new in the reinforced concete 14 effect. And, as you know, Germany, for the most part, 15 concentrates on steel containments.
16 MR. MARK: When did you have the round-robin 17 predictions available?
18 MR.~ CLAUSS: Wall, we raportediv --
l l
O 19 MR. COSTELLO:
~
Go to the next slide.
23 MR. CLAUSS: Let me finish this slide first.
21 It was before the test, but I'll go into that a 22 little bit more.
23 Another advantage was that we were able to 24 evaluate the ability of different codes to correctly l
25 calculate response. And they have a list there of different i
l REPORTING _ --
! ssRviom a recorri of excellence
77 1
codes that were applied by the various groups.
8 2 And finally, I think it's been a very beneficial 3 experience for all of us in that we've been able to exchange 4 and share information about all of these tests but on other 5 programs of interest in containment integrity.
6 Okay. The report which summarized the pre-test 7 predictions was issued before the test. I think it was 8 issued in May. The test was in July. And I believe some of 9 you at least have received a copy of that report.
10 What it boils down to is separate sections giving f '
L. '
11 detail' of each participant's analysis. And then we Et 12 Sandi : tempted to summarize those analyses as well, give 13 appropriate introductory material.
/ ^j 14 Another feature of that report was that we asked v
15 all the groups to give us essentially standard plots which 16 represented pressure history of strain and displacement at 17 locations that were instrumented in the model. So by taking
, .- 18 that approach, it allowed us to make not only comparisons 19 between the difference analyses, but also a pretty immediate I
20 comparison between analyses and experiment.
21 There was quite a range, obviously, in that the 22 capacities was anywhere from 130 to 190. I would say, 23 though, the main reason for the difference was not at the 24 calculations are responsible (inaudible), but that there was 25 a much -- there is a lot of difference in the way that it REPORTlNG SERVlOE a record of excellence
'7A I
was interpreted in the criteria that were applied.
8 2 MR. SIESS: I have to say I'm disappointed.
3 I suggested at one time that you ask these 10 people to 4
predict a pressure at which they had fairly high confidence 5 it would not fail.
6 MR. CLAUSS: Well, sir, I didn't want to 7 disappoint you and we, in fact, asked that question. And 8 '
it's really -- I don't have a viewgraph on it, but it is in 9 the report. '
I think I brought a copy with me.
H}
MR. SIESS: I didn't see it in the summary.
11 MR. CLAUSS: It's in the Executive Summary.
12 I can look at it right now and give you the numbers if you 13 would like.
{} 14 MR. SIESS: No. Wait until you go through 15 the rest of the stuff.
16 MR. CLAUSS: Okay.
17 MR. SIESS: I just missed it somewhere, i 18 MR. WARD: Well, are you going to explain i
O 19 what you meant by different interpretations of failures?
l 20 Are you going to get into that a little bit more?
21 MR. CLAUSS: I could try to describe that a 22 little bit with this slide, which shows the predicted
! 23 capacity as reported in this pre-test report by the various l
24 organizations, and also describes the limit mechanism phase 25 that they thought would be critical.
O musamt
~ spgM13f SERVlOE a arcorri of excellence . . .
79 I I wasn't really planning on going into this in a 8 2 lot of detail. Let me just kind of make some general 3 comments on the differences between the criteria.
4 The people that are near the high end of the range 5 in the 180s, 190s, those people didn't really try to analyze 6 strain concentration in the liner. They did an axisymmetric 7 analyses and they wanted to know what the ultimate 8 structural capacity of the model was.
9 Now, given that, there's really no way we can say 10 these numbers were wrong. If the liner hadn't failed, we (T
L.i 11 would have gone all the way out to structural failure. I 12 actually believe that the 180 number is probably pretty 13 reasonable.
14 So they did not interpret failure fi
\.., , /
MR. SIESS:
15 as leakage?
16 MR. CLAUSS: Well, the ground rules, I must 17 say, were to evaluate exact leaks when the model failed.
7, 18 Instead it was to find accidental leaks.
i ;
'. 9 But, in reality, their interpretation was that the 20 liner would not tear; and therefore, they took it all the 21 way out to this --
22 MR. SIESS: If you can't answer the hard 23 questions, it's always best to go ahead and answer the easy 24 one.
25 MR. CLAUSS: Well, I guess I have to admit (N _ . _ _ . _ . -
REPORTlNG SERVLCE 1
a recmri of cxcellence
8 0__
I that Sandia'took that same approach. We felt there was 8 2 enough flexibility in the liner that even given strained 3 concentratioac on the penetrations probably wouldn't be a 4
problem. So we went out further.
5 MR. SIESS: Let the studs off, you probably 6 let the -- without the studs, you were probably right.
7 MR. WARD: Okay. So the local liner tear 8 failure was unexpected by most analysts?
9 MR. CLAUSS: I don't know. I mean, it wasn't 10 gm that it was overlooked. It was just undetected. You 11 thought it was going to be ductal and --
12 MR. SIESS: Now, one -- the PCA/CTL EPRI 13 stuff, I guess, predicted a liner tear, but at the knuckle.
(} 14 Does it need a test of a knuckle or the (inaudible).
15 MR. CLAUSS: You know, I don't know if it's 16 really fair to say it was unexpected. It was certainly a 17 possibility that we have admitted. But we also didn't
- 18 really have the capabilitiec in our analyses to go in and do 19 a very rigorous analyses of those strained concentration 20 areas. And to be honest, I'm not sure we do right now. The 21 stud interaction is a very difficult problem to follow.
22 MR. SIESS: Now, in that respect, I see 23 complete parallels between this and the steel containment.
24 MR. CLAUSS: In your inability to amend all
, 25 the -- '
O mutmant REPORTING _ . _ - - .
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I MR. SIESS: Well, you have the situation 8 2 there, you recognized a potential concentration sort of 3
that, well maybe ductility will take care of it. You 4
couldn't really handle it anyway, so you went on, and that's 5
where it failed.
6 MR. SHEWMON: But in the absence of vented 7 containment, this is the -- I would argue that this is the 8
best kind of a weak to have because it eliminates gross 9
failure. It gives you a lot of paths where you're going to
)
10 deposit aerosals instead of letting them out into the
~]
11 atmosphere.
12 MR. SIESS: Yeah, it's great.
13 MR. SHEWMON: So I'm not sure it ever did I
14
- fail.
15 MR. SIESS: We ought to build them when new 16 weak spots. You know, take the grinding wheel and go in and 17 put a few around it, 18 MR. EBERSOLE: It looks like you have --
i -.
19 MR. WARD: I think this argument about 20 depositing aerosals in effect is a little -- it's kind of a 21 hopeful comment. I'm not sure we've got much evidence, but 22 that's going to happen in a reliable and effective way.
23 MR. SHEWMON: Well, I think you ought to look 24 back at the evidence because I've been told -- I can't give 25 you chapter and verse, but I've been told it by enough l
o --
l O 1GNNN REPoliTlNG SERVlCE a nconi of excellence
82--.
I people that I suspect that chapter and verse is there. But 8 2 partly, these things bave to -- it's colder out there.
3 MR. SIESS: But, Paul, as I recall, for the 4
slow overpressure case, loss of containment cooling. And 5
they figure most of the aerosals are going to be settled out 6
by the time we get to this. And if it's not an explosive 7 release which could lift them off, you really don't have 8
much aerosal in there. You don't have much of anything in 9 there.
10
( '3 MR. SHEWMON: Only noble gas primarily?
11 MR. SIESS: That's what they say. For the 12 slow overpressure, if the containment does fail, so what?
13 The releases are very small.
14 On the other hand, if a containment ruptures
(;
15 explosively, like the steel one did, that itself is a 16 catastrophe as far as the immediate concern, whether it 17 released anything or not.
,y 18 MR. WARD: So all the filtered vents that the
( 'l
'~
19 Europeans are putting in aren't protected against us, that's l 20 a no, never mind r.nyway.
l 21 MR. SIESS: Well, it could be earlier.
22 They're talking about venting a lot earlier. They're 25 talking about venting of one to one half design pressures.
l 24 And that isn't four days out, either.
25 MR. WARD: Yeah, but the capacity of those U, . 1mNN m REPGATlNG SERVlCE a recowl of excellence _
R3 I
vents is associated with slow overpressure from the --
8 2 MR. SHEWMON: It's a modest capacity, as I 3 recall.
4 MR. SIESS: It's not as slow as I'm thinking 5 about.
6 MR. WARD: Well, it's pretty small. Most of 7 them are.
8 MR. EBERSOLE: Well, hasn't this test really 9 disclosed that in a fortuitous matter, you've got an ordered o 10 failure, which is desirable 7
)
11 MR. SIESS: That's what we're --
12 MR. CLAUSS: But we don't want to make that 13 general conclusion yet. The one thing we're having to 14 include is the effect of temperature, which we've already
(}
15 said, we'll put the liner in compression and we could delay 16 this liner (inaudible) relative to other possible failures.
17 So you can't just make a general conclusion 18 pertaining to all the containments out there. Aside from f3
%) 19 the temperatures is heated also, obviously designed it, the 20 ankor details are different. So you really have to look at 21 the containment on a case-by-case basis.
22 MR. SIESS: But it's awfully hard to hold the 23 pressure on this system with any kind of leaks. And that is 24 what you showed. You had an ability to pressurize one-25 third of the volume for a minute. Right?
O -
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1 MR. CLAUSS: Uh-huh.
8 2 MR. SIESS: For at least 4,000 cubic feet per 3 minute --
4 MR. CLAUSS: Yes. In slow pressurization 5 basis scenarios, there is no doubt this would have precluded 6 further pressurization'. But there are scenarios where you 7 have very rapid pressure.
8 MR. SIESS: Oh, if you're talking about a 9
hydrogen burn or a hydrogen detination, that's something to else.
Il MR. CLAUSS: Okay. As far as talking a
!2 little bit more about tne uncertainties (inaudible) 13 criteria, the people on the low end tended to associate
(}
14 failure with general yielding. And that's sort of the 15 opposite approach that's going all the way out in ultimate 16 failure. Ultimate failure is not conservative and is very 17 optimistic. Narrow yield is very pessimistic. What you're 18 saying is that once you start being moderate displacements, O 19 you don't have confidence in your prediction and because of 20 this, that's the failure pressure.
21 MR. SIESS: As I recall, there was some 22 predictions that were pretty close on the pressure and there 23 were other predictions that at least predicted liner 24 tearing, but they were not the same.
i 25 MR. CLAUSS: Well, I think the only group 1
0 --
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that explicitly predicted liner tearing was EPRI, which is 8 2 actually ANATECH. And one of the British ones had predicted 3 liner tearing at 190 or something like that, I recall.
'4 MR. CLAUSS: That's -- I would have to go 5 back and double-check. That's not really what I recall. t 6 MR. WARD: Well, in this table, it says "NII, 7 130, local tearing around the studs."
8 MR. CLAUSS: Okay. 'Ihey said that there was 9 some possibility, but that basic --
" ") MR. WARD: Okay. That was sort of an 11 asterisk on their thing?
12 MR. CLAUSS: Yeah, right.
13 MR. WARD: Okay. I see.
1-4 MR. CLAUSS: The one that they believe most 15 likely will transfer back.
16 MR. BENDER: Well, as it turned out, none of 17 them addressed the failure mode that you observed.
18 MR. CLAUSS: Who was that?
O 19 MR. BENDER: No one was 100 percent correct.
20 They all admitted the potential, but they didn't really --
21 all the analysis up there is focused on a different part of 22 the structure.
23 MR. CLAUSS: Uh-huh, sure.
24 MR. BENDER: And so the only relevance of it 25 has to do with, well, how close to that failure mode were O - . .
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REPORTING SERVlOE a wcmd of excellence
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I And at the moment, I don't think we have $
you in that line?
8 2 an answer to that.
3 MR. CLAUS 5: I agree. I guess that's one of 4 The ultimate capacity, the things I was trying to count on.
5 180, that might be a good number. We don't know that since 6 we didn't reach that point.
7 MR. BENDER: On the other hand, we don't 8 really know yet what the purpose of the analysis ought to 9 be. The NII uses its analysis mainly to evaluate whether 10 the peole that are submitting their safety documents have a
( )
11 reasonable basis. I don't think they -- most of them even 12 looked into the basis on which these pressures could occur.
13 And so I'm not prepared to say that what they did makes much 14 sense as an analytical method to -- for the purpose of I
(~)
w/
15 evaluating this structure.
16 But it was an interesting exercise. I did scan it 17 fairly carefully and waat 'he c various analytical methods are 7, 18 and what they can Eccomplish. And just from *,he standpoint
( ) 19 of comparing the simplistic approaches with the more 20 sophisticated ones, I conclude that it doesn't make much 21 difference which ones you use. You get about the same 22 answer anyhow. But for the purpose of this --
23 MR. CLAUSS: Tell me, which were the simple 24 methods that were used? They were all fairly sophisticated 25 approaches.
LJ RENNury REPORTlNG SERVlOE a record of excellence - - - - - - - - - _
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MR. BENDER: Well, they used -- all of them 8 2 used computer codes, but some tried even to do a 3D analysis 3 and some did 2D analysis, and some ignored some of the 4
complex structural areas because their codes could only deal 5 with axisymmetric conditions. And there is a whole litany 6 of things that determine whether the method was 7 sophisticated or not. And actually my impression was that 8 aside from the EPRI analysis, most of them were very 9 simplistic. That's my perception from maybe looking at the s H) report for a day.
C/ 11 MR. CLAUSS: Well, I think that's true that 12 most of the people did only an axisymmetric analysis. And 13 relative to the 3D analysis, it gets simpler, but it's still
, ) 14 a very sophisticated (inaudible).
v 15 MR. BENDER: Well, I didn't -- this is a 16 long-standing argument. It's wasted it here.
17 MR. WARD: Dava, you thought -- I think you 7, 18 said you thought maybe the 180/190 or what they're
(' ~' '
19 predicting wasn't far off. But I thought I heard in the 20 discussion earlier that if the liner hadn't -- when there 21 was some conjecture, discussions about the failure that if 22 the thing were retested with the bladder, I guess, in that 23 discussion, I thought the opinion was it probably wouldn't 24 go much beyond the --
25 MR. CLAUSS: What I guess the point I was a _ _ _ _
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I trying to make was that if the liner had not developed at 8 2 their rate, that the 180 would be a reasonable number. When 3 you tear the liner, the load --
4 MR. WARD: Oh, you're losing that strength 5 through (talking over each other). Okay, I understand. But 6 this reminds me a little of, you know, large break LOCA 7 Calculations where three or four people come in with 8 different versions of the codes and they all calculate about 9 the same peak clad temperature except some are during 10
\>
e) blowdown and some are during reflood. And so I don't 11 know -- complicated business.
12 MR. SIESS: You know what this reminds me of?
13 My daughter worked for an agricultural economist once. And
' 14
, his advice was, you could predict the price for a commodity 15 or you could predict a date, but don't ever predict both.
16 Bu t, you know, the outstanding things here is the 17 nuraber of people that thought that the wall base 18 intersection was going to be the weak spot. And EPRI, vhc
( ~') 19 had actually made tests of that thing, thought it was going 20 to be the weak spot. And it wasn't.
21 MR. CLAUSS: Okay. That's one of the things 22 that was discussed in detail in the meeting that we had in 23 November that Jim mentioned earlier. And there were several 24 possible reasons why that area wasn't important. It all 25 comes down to things that were done in the modeling of the 1
r -
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I basemat. A lot of people didn't include the soll. And 8 2 there's some evidence to test that by any introducing a 3
flexible soil, they actually get most different shears and 4
(inaudible) at the wall basemat juncture. That's one 5
element that's not consistent with that analysis.
6 MR. SIESS: What is the support of the model?
7 MR. CLAUSS: I'm sorry. Say, again.
8 MR. SIESS: What's the model sitting on?
9 MR. CLAUS: What's the statement? It's 10 sitting on a mud --
c7 y i 11 MR. SIESS: Is it on soil?
12 MR. CLAUSS: Pardon me?
l 13 MR. SIESS: Is it on soil?
( 14 MR. CLAUSS: Yes. Dan, you could probably 15 describe the soil a little better than I can, 16 MR. HORSCHEL: Maybe he didn't catch the 17 point. We have a working man underneath the foundation mat 18 for the containment. That working mat is about six inches 19 thick. And, of course, underneath that, we have soil. Some 20 of that soil was imported and impacted for that containment 21 model. That layer is probably about 15 inches thick. And l 22 then we would just go back to the natural soils which were 23 there in place.
l 24 MR. SIESS: So for practical purposes, your 25 mud (inaudible) would be the contact?
o __
v 1GNNmW llEFOliTING SEliVlCE a INcorri of excclience
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I MR. HORSCHEL: Yes. And we do have a bond 8 2 breaker in that we mean that we place the foundation mat on 3
the (inaudible).
4 MR. SIESS: Do you have any idea what the 5 separate modulus is for that soil under it?
6 MR. HORSCHEL: We did some plate berry tests, 7 like you do for a spread for ASTM standards. We have those 8
calculations. But we didn't really project the stiffness of 9
the soil or separate modulus or anything like that. We have 10
, <-} the data and we kept it there and we let the analysts use Lj 11 that in the way they felt more comfortable with that.
12 MR. SIESS: And they think that was the 13 fcetor?
14 l MR. CLAUSS: Yes. As I was going to say, the 15 number of differences in the way the basemat was modeled.
16 Some people chose the treatments for those ridges, some i7 , prsople modeled flexibility, Some pecpio didn't include the
)
18 mud of the (inaudible). There's also layers of concrete, 19 protective cores, and then a fill slab above the liner that 20 there were a lot cf differences the way people modeled. And 21 some people thought it wouldn't be important, others did.
22 And you see a big difference in the results for 23 shears and (inaudible) as well as basemat uplift, depending 24 on how those details are modeled.
25 So we need to converge on that and find out which !
/~ ,
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are the important details and how that affects the model.
8 2 MR. SIESS: What's the worst condition, a 3
rigid face or a flexible soil?
4 MR. CLAUSS: I guess I don't want to make a 5
conclusion on that. But my opinion is, from what I've seen 6
is that the flexible soil is actually the worst condition 7 the reports shown of the wall.
8 Now, the reason for that is that when you 9
introduce flexibility of soil, you get more bending in the 10 basemat or more flotation in the basemat is a better way to Il put it. And the cylinder essentially has to conform to the 12 l curvature of the basemat at that intersection.
13 So by introducing flexible soil, they're getting 14 greater curvature at the base of the wall which leads to 15 higher shears and runs within the wall. l 16 MR, SIESS: I guess I'm having e, problem.
17 It's just hard for me to believe that the rotation of that 18 big basenat was significant compared to'the rotation of the
. 19 base of the wall, the wall itself, which is much, much 20 thinner. But go ahead. I'll worry about it. I don't know 21 whether that's real not, if that could be calculations.
22 MR. CLAUSS: Well, I've got a number of 23 v1ewgraphs here that show various comparisons between the 24 analyses and the final results. I guess I'm only going to l
25 put a few of them up. And really -- the point I'm going to l
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1 make and they're making some disagremeent, there may be some 8 2 disagreement from the Committee. But in my mind, I felt 3
that the agreement between the analyses for global measures 4
of the response, like radial displacement to midheight was 5
really very good.
6 MR. SIESS: This is radial displacement at 7 midheight?
8 MR. CLAUSS: This is radial displacement 9 of __
10 r^> MR. SIESS: Who is that character with the i
11 plus signs?
12 MR. CLAUSS: The plus sign is the 13 experimental data. That's the actual measured response.
14
( ) MR. SIESS: Okay.
15 MR. CLAUSS- And these are the -- I don't 16 have identifiers on here -- and I apologize for that. But 17 in the report, you can find them. But each different line 18 type represents different analyses by a different group.
7~ ,
e 19 So I guess the only point I was going to try to 20 make here today was that --
21 MR. SIESS: I'm fascinated that they 22 absolutely consistently underestimated the displacement of 23 the range.
24 MR. SHEWMON: Now, that's after --
25 something's gone plastic. Was that after the rebars?
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1 MR. SIESS: No, it's after the concrete 8 2 cracked, is what it is. I'll be willing to bet you.
3 MR. EBERSOLE: You mean that verticle like is 4
whether you lost the concrete tensile strength?
5 MR. SIESS: No, that's where this line 6 yields --
7 MR. CLAUSS: This is clarifying yielding the 8 steel.
9 MR. SIESS: That's where the lineman yielded.
r 10 MR. CLAUSS: What I think Chet has learned
()'
11 is, you don't ever see a jump in the curve, the measured 12 curve corresponding to the loss of the concrete --
13 MR. SIESS: So they're all viewing at any
(')
'w) 14 specu- loss of displacement'that was observed.
15 MR. CLAUSS: It's not too small.
16 I would like to defer this to Ronoy because he's 17 done a lot of investigation as to what e:<actly happened.
,s - 18 MR. SIESS: No, that's all light. I'm
( )
19 just -- it's just that consistency.
20 MR. CLAUSS: You'll see that throughout the 21 data. And what we've found, in fact, is that for the 22 membrane response of the cylinder, a no tension model for 23 the concrete seems to compare much better with experimental 24 results than --
25 MR. SIESS: Well, obviously. That's the only tJ inaNN1alw REPORTlNG SERVlOE l a recmri of excellence - __.
04__
I kind I would ever make. Heck, I did these kinds of --
8 2 MR. CLAUSS: Well, I wish we had the benefit 3 of that wisdom a year earlier.
4 MR. SIESS: And did they actually assume 5 concrete stiffening?
6 MR. WEATHERBY: Not on this. And for the 7 radial displacements, the hoop strength of the concrete is 8 where --
9 MR. SIESS: Hoop strength 7 10 MR. WEATHERBY: The hoop strength. It's r's L ')
11 where the concrete cracks due to hoop stress.
12 MR. SIESS: Yeah, but you've got cracks at 13 such close spacing that your stiffening between cracks is
~
(~j^) 14 going to be negligible.
15 MR. CLAUSS: Well, apparently, you didn't 16 need the results of the test.
17 MR. SIESS: Well, I've tested a lot of
,, 18 concrete, you know. It took the Los Alamos guys three years t /
19 to 'oe convinced of that.
20 MR. WEATHERBY: 'n all of these calculations, 21 though, about 110 psi say that the concrete will not be 22 buried in the hoop.
23 MR. SIESS: But they must have assumed some 24 stiffening.
25 MR. WEATHERBY: No, not by -- by 110, even g _ _ _ _ .
O MUNNEN REPORTING SERVICE l l
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I the people that assumed that would --
8 2 MR. SIESS: Well, then how did we get that 3
much difference?
4 MR. WEATHERBY: Well, the only thing I can 5
think of is maybe the seismic bars aren't carrying as much 6 load as anticipated.
7 MR. SIESS: Okay. The question of --
8 MR. CLAUSS: The afternoon is going to supply 9 that.
10 s
MR. SIESS: That's an interesting subject, k.) 11 gentlemen.
12 MR. CLAUSS: Let me just kind of move towards 13 the end of this discussion because Randy is going to be
(} 14 talking about the analysis in a lot more detail in a minute 15 here. And we have a pretty full schedule this afternoon.
16 MR. SIESS: That next figure, though, is aven 17 more exciting, f~ 18 MR. CLAUSS: With the vertical displace:nents, i l 19 yeah.
20 MR. SIESS: The vertical displacements.
21 MR. CLAUSS: Again, let me just defer because 22 I think Randy is going to do that difference between the 23 behavior and (inaudible) direction as opposed to hoop 24 directions.
25 So let me just kind of wrap up this discussion of 1
1
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I the group effort. A lot of this Jin's already mentioned.
8 2 After the test, the first thing we did was try to get the 3
data to the various analysts as soon as possible, and that 4
went out in early August, essentially about a week after the tort. The testing analysis was featured in SMiRT, got a lot 6 of the attention, generated a lot of interest at that time.
7 And then as Jim said, we had the entire group 8 here, actually about 30 people in all in early November.
9
.Tnd at that time, all these people who that did the analysis 10 were allowed to go out to the test site and inspect the 11 model in detail. We also had essentially two and a half 12 days of in-depth discussions on the differences in the 13 modeling between the various groups and exactly what 14 improvement needed to be cade to improve the comparison
{'
15 between analysis and espertuent.
16 There was also some discussion of future plants 17 and what the various groups were going to do. And I believe
. 18 there were six of the ten groups plan to do additional O 19 analyses. And of those six, I believe at least five of them 20 are planning to do what we would call local analyses to try 21 to evaluate this interaction between the studs, liner, and 22 the concrete and to see if they can understand exactly what 23 the limit mechanism was in the model.
24 We also will -- well, we agreed to produce a 25 second report, essentially the same type of format as the O mment REPoliTlNG SERVlOE l a reconi ofexcellence
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pre-test report except this report will document comparisone 8
2 between analysis and experimant and also document any 3
post-test analysis that were done that lead to additional
.s 4
understanding of the model behavior.
5 And right now, we're kind of shooting for a target 6
of like June 1st for the draft of that report. That may be 7 optimistic because some of our post-test inspections will be 8
done and we will keep us from having to -- occur quite as 9
fast as we might have liked within 90-day information before 10 n they can complete their analyses. So it may be later than d 11 June.
12 The noxt thing I have in there is just sort of a 13 summary of that meeting and you may_put that out and you can 14 i read that if you're interested. And I guess these are just' '
15 kind of my o'ovious conclusions.
16 There are two thin.js that we're trying to do with 17 the analysin as far as comparisons experiment. One thing 18 is, we want to know how well we can calculate the response.
19 We want to know if we can track displacements, the etrains.
20 Then the second thing that we want to know is, can 21 we interpret failure? And they're really separate issues.
22 We use the calculated response parameters in a failure -
23 (inaudible) to interpret failure. And the calculations ;
24 don't know about that process.
I 25 So the first thing I want to make sure we can do O _ _ _ _ _ _ _ _
m m Eur l
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I is do the calculations. And my conclusion based on what 8 2 this group has done in comparison to the experiment, so that 3 would essentially be a good reasonable (inaudible) of 4
predicting global measures of containment response. The 5 difficulty is, the thing that we're working on right now is 6 the localized behavior, behavior of run penetrations, and 7 (inaudible) studs and things like that. And that's 8 something that we need a lot more work on.
9 MR. EBERSOLE: What you're telling me, that 10 you're concerned with the color keys of design, the fine
{
t 11 structure of design is where it is, the fine structure such 12 as run penetrations?
13 MR. CLAUSS: That's right. If we want to get
/ 14 a better resolution in our analytical capabilities, that's
- w. :
15 what we need to look at, is all part of the detailed design. -
16 MR. EBERSOLE: In my view, that's true of 17 dynamic systems. It's all in the fine structure.
18
()
m MR. CLAUSS: That's trua.
19 MR. BENDER: Not clearly to really need to 20 know. If all you're trying to do is find out at what stage 21 you can -- what pressure you can go up to before something 22 fails, if you're going to design for controlled failure, 23 then it may be important to know these things. Somebody 24 needs to make the case for controlled failure in order to --
25 MR. SIESS: Control nonfailure.
77 U 1 HON 1FW REPORTING SERVlOE a reconi of excellence
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N 94-I MR. BENDER: What?
8 2 MR. SIESS: You said you had the figures on 3
their predictions of no failure?
4 MR. BENDER: For control --
5 MR. CLAUSS: Yeah, let me get those.
6 MR. SIESS: Yeah, I would like to see them.
7 MR. BENDER: I don't know what that means.
8 MR. SIESS: I wish we could just --
9 Jim, can't you convince them to take Item 3 off of to
~) there. I hate to think that the NRC spent more than $2 for 11 that.
12 MR. CLAUSS: What's that again?
13 MR. SIESS: I would hate to think that the 14 j NRC spent more than $2 of our hard-earned money to prove 15 that the concrete is not perfectly bonded, n
16 MR. CLAUSS: Well, first you know it's not 17 perfectly bonded, but it's a question of what assumptions s 18 you can make and analysis, an analysis rtill reasonably i )
~
19 tracked. And this is -- you know, as a matter of fact, this 20 is an assumption that most people make in their analysis 21 before they tell us.
22 MR. SIESS: It's ridiculous. That's because 23 they're analysts. That's what I asked you. They don't know 24 anything about the behavior of concrete and reinforced 25 concrete and steel. And if they did, they would never make l
t) lWN NN REPORTING SERVlCE a N$oni of excellence
100-I that kind of an assumption.
8 2 And I can show them dozens of tests that show that 3
that --
'I MR. CLAUSS: But can you show them how to 5 model studs and --
l 6 '
MR. SIESS: I'm not interested in how to 7 model it. I'm interested in the behavior. I think if they 8
model the behavior, they shouldn't be making the analyses.
9 Just because they don't know how to model it is no reason to for making an absurb assumption. That's solving the easy f 3 U 11 problem because you can't solve the difficult one. Modeling 12 something that's not true is no help to anybody.
13 MR. EBERSOLE: Would you agree to change that 14
{ '; last sentonce to say, "It is relative to assume that it is 15 always smart to try to bond the concrete?"
16 MR. SIESS: There is a bond between concrete 17 and a plate, but it's not very J arge and it's very easily
- 18 broken. And to assume it for something that's going to go
~
19 up to crack and go to these things, once a crack forms, the 20 bond stress immediately adjacent to the crack is infinite.
21 The concrete is moved and if the steel can't move the same 22 amount of the concrete, the bond is infinite. So it breaks.
23 Dale (inaudible) pointed this out in 1917.
24 MR. WARD: Well, still --
25 MR. SHEWMON: You had a point that you wanted U lWNNEDY REPORTlNG SElW10E a reconi of excellence
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to read there.
8 2 MR. WARD: -- I mean, that's a valid lesson 3
from this experiment. And if the particular designers and 4
analysts finally have learned it, that's great.
5 MR. SIESS: I don't know whether they've 6 learned it. '
7 MR. WARD: I would say it's very --
8 MR. BENDER: We're just starting the application a little bit. For the purpose that it has been
() used for in the past it was probably all right. But at this -- for analyzing this failure just doesn't fit because 12 the failure is involved -- involved something where the 13 liner and the concrete do not work.
14 f]
'is' MR. MARK: Chet, would you enlighten me.
15
, What arc the studr for?
MR. SIESS: The studs are to prevent buckling under temperature loading.
18
(,-)
' ~ '
MR. MARK: Okay. So they do -- are needed 19 for some purpose?
20 MR. SIESS: No. I'm not sure that the --
21 MR. MARK: If they were left out --
22 l MR. SHEWMON: I think he wants to answer one 23 of your earlier questions about what they said is reasonable 24 upper limit.
25 MR. SIESS: Okay.
l U, 1mNNN liEPoliTING SERV 10E a iccmd of excellence
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I MR. CLAUSS: We asked them to give us a value 8 2 at which they had high confidence and low probability 3
(Anaudible), which is the number you gave me.
4 MR. SIESS: Right.
5 MR. CLAUSS: The estimates ranged from --
6 only seven people were willing to respond to that, first of 7 all, seven of the ten. Those values ranged from 100 psig to 8
160. I will say that only one was above the actual failure 9
pressure. The actual amounts were 100 -- 100 twice, 10 71 basically -- 105, 127, 135, 138, and then the 160.
')
11 MR. HORSCHEL: It is in the summary of the l
12 report, but it's not in tabular form.,
13 MR. SIESS: Yeah, I just missed it.
14 (l
L:
MR. BENDER: Who predicted 1607 15 MR. CLAUSS: ORS from Germany.
16 !
MR. BENDER: What was their range for 17 failure?
7.- .
18 MR. CLAUSS: They're range for failure was
~
19 167 to 189. So they had a lot of confidence in their 20 analysis that probably wasn't justified.
21 MR. SIESS: Yeah, they're a prediction of 22 high confidence.
23 Let's see. You had 120, you said, to 160?
24 MR. CLAUSS: 100, 100, 105, 127, 135, 138, 25 and 160.
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MR. SIESS: And the range on failure loads 8 2 went from a low of 128 to a high of 190, I guess. It's a 3 little smaller range.
4 MR. WARD: What do you include --
5 MR. SIESS: They did a lot better on that.
S Well, that's a little easier MR. CLAUSS:
7 number. It's much casier to predict what the containment 8 will not fail.
9 MR. SIESS: Much more useful number.
10 MR. CLAUSS: But I think that's one of the v
'}
11 things that maybe I should have made a point about, is that 12 when we do analysis -- and our objective of the analysis is 13 actually to address several concerns. And one of them is ,
() 14 the concerns you-all share, which seems to be when the 15 containment will not fail. You can address that concern 16 with fairly simple analysis method, and I think we're --
17 state-of-the-art is there right now. That leaves u lot of 7s 18 extra work that needs to be done to assess that particular
!l 19 number when a containment will not --
20 MR. SIESS: After this test?
21 MR. CLAUSS: After this test, right. There 22 is a lot of uncertainty, and I'm not sure we'll ever be able 23 to resolve it to determine a problem in predicting actual 24 failure. Now, I realize you don't believe that's important, 25 but there are people cut there that are asking us for that n __ _ _
l tJ mNNmw 11EPoliTlNG SEliVlCE a reconi of excellence
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I number. So we're trying to do --
8 2 MR. SIESS: Who's asking you for that? Is 3 NRR asking for that?
4 MR. CLAUSS: I'll defer to Jim on that one.
5 MR. SIESS: Is NRR asking for actual failure 6 loads?
7 MR. COSTELLO: It's hard telling what NRR is 8 anymore.
9 It is -- in response to your question, the generic
'- 10 issue and all that business is all rolled in now to the 11 research office. But the people who are looking at the 12 severe accident applicability question are into that, yes.
13 MR. SIESS: Well, some of the PRA people l 14 would like to know a number like that. And some of the PRA 15 people, I thought at one time, were convinced that what they 16 would really like to have would be a probability of leakage 17 as a function of pressure and a range of uncertainty.
- 18 You know, ,
slly they didn't assume anything
() 19 about leakage. They a sumed that they didn't leak at all 20 and the pressure just went up. Then they began to realize 21 that it might leak at lower pressures if the pressures 22 wouldn't get that high. And I don't think they're ever 23 going to get either one right.
24 MR. COSTELLO: Well, I think -- my own 25 perception is that there is a little more modesty in the g _ _ _ . _
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1 demand for what one has to know to make to be useful for 8 2 these PRAs and risk-based assessmonts. But the fact of the 3 matter is that in the regulatory, you know, sense, severe 4 accident considerations are treated on risk, on risk based 5 in their models.
6 Now, I think people, as they are being more modest 7 and all, they feel they have to know about containment 8 failure models to come up with an attractable method for 9 regulatory purposes. But there is also something about the H3 failure mode, knowing the failure mode that enhances your r-U' 11 confidence about your lower bound prediction; that is, if 12 you're working and you're not -- if there's a significant 13 possibility of a failure mode racking around there that you 14 never accounted for, you, by definition, don't have the (G~T 15 lower bound.
16 MR. WARD: But look -- yeah, but look at --
17 Chet, you know, I really disagree with you on the importance 18 of knowing failure loads and failure modes. I mean, I think O 19 that the move toward regulating the risk to the extent that 20 it's possible and you've got the basis for doing it is good.
21 And I think you're sort of taking the approach that you 22 accuse some of these analysts of things in the forum in that 23 if you can't provide the hard answers, you're going to give 24 me the easy answer. And, you know, that's great. But --
25 MR. SIESS: No , let me put it differently.
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1 What have we learned from the two tests so far, the steel 8 2 test and the concrete test? We've learned a lot about 3 failure modes. And learning about failure modes is 4
important.
5 What have we learned about failure loads? We've 6 learned that failure loads depend on details. Okay?
7 Now, if somebody tells me I've got to know more 8 about failure loads, we're into a research project of almost 9 infinite magnitude. Because there's about 40 different 10 kinds of containments out there. And even if I take two 11 presumably identical, they're going to differ in details.
12 So I think it's a hopeless effort to try to pin down loads j 13 for ultimate structural failure with any degree of
(} 14 confidence that will do anybody any good. We would have to 15 test too damn many things. Modos are important. We learned 16 a lot about modes.
17 MR. COSTELLO: If you'll bear with me, I 18 think you'll be here this afternoon if we have a chance to O 19 have Mr. Clauss come back in and talk about the application 20 of what we've learned from the steel containment as to 21 Sequoyah.
22 But I think we have a middle ground here that is 23 useful and does take account of what one heard about and 24 what procedures are important. I believe within a year or 25 two, we'll be in the same status with regard to concrete I
f O mana,=
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8 2 You've got particularly Dr. (inaudible) has titled 3
that. There are churning hypotheses about the possibility 4
of local failures.
5
- Again, to say that you're sure something won't 6
fail, you have to be pretty sure that you won't have a local 7 liner failure, and you have to know something about that. I 8 thlnk we're on the road of learning that.
9 MR. SIESS: Yeah. But if I look at accident 10 management and I've got a containment sitting there and the 11 pressure is building up, and I've got to make a decision and 12 I've got some way of venting it, cool ' vater or any other 13 way. And if I believe that I don't want it to rupture and 14 scare the hell out of people, weather or not it hurts them, 15 I want some idea of when it won't fail. I don't want to 16 wait until 150 or 140 on this one. I'm pretty confident at 17 120 or 125 it's not going to fail structurally. It may 18 leak. It may leak from the beginning if the valve was open.
19 And everybody that's talking accident management with 20 venting filter, filter vents are talking about one and a 21 half design pressure on most as a maximum. Some of them are 22 talking one design pressure.
23 I think the Swedes are going to one and a half, 24 the French one, one and a half, the Germans somewhere in l 25 that neighborhood. And I'm sure they've got plenty of O 1am e nt
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I confidence that it's not going to rupture at that point.
8 2 But I'm not going to sit by and wait for that thing to go.
3 I don't want to get anywhere close to that.
4 I remember back when we first started talking 5
about instrumentation to follow the course of an accident --
6 what is that? Reg Guide 1.97. We learned that the gauges 7 to measure containment pressure went up to SIT and that's 8 all. They had no way of knowing what the pressure was once 9
it got above -- 15 percent above the design pressure. And to we said, 11 "Yeah, wouldn't you like to know what the pressure is in the 12 containment up to two or three times that?" Why? So we can 13 do something before it went ...
14 But my main concern is that if we really think we
[}
15 have to know what the containment failure load is, it's 16 just -- what we've learned from these tests is, is details.
17 Now, how do you get a generic answer?
18 MR. COSTELLO: Well, my only response -- and i
l 19 I don't believe it's a generic answer. For those plants, we 20 brought fact-specific detail. Not only the details, but 21 even gross difference in the plant and design for that same 22 type of containment. The classic example is Sequoyah versus I
23 WATS bar. The same design pressure, great differcnce is the 24 plate barriers because of perceptions of economics, i
25 The realization of economics, I guess. But the O __
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100-1 failure pressure (inaudibles) are different.
8 2 MR. SIESS: Not necessarily. The crack might 3 occur where the plates are the same thickness. You might 4
never get up to the upper part there with it.
5 MR. SHEWMON: Well, Jim, one of the pieces of 6 paper that I can't lay my hands on but I must he.ve in my 7 room that I've not brought out was something where some 8 member of the Staff, perhaps you, had listed in order five 9 factors, all of which were multiplied to to gat --
10 MR. SIESS: That was (inaudible).
11 MR. SHEWMON: Roughly how much more than the 12 design pressure one was comfortable at. And the least from 13 those numbers, they all came out about two for steel,
{} 14 15 concrete --
MR. CLAUSS: Two and a half is closer.
16 MR. SHEWMON: Well, Dave, they wore over two.
17 So in a sense, that's going back to what Chet was saying 18 again, isn't it, that --
0 19 MR. COSTELLO: That's what Chet was saying.
20 And people, a couple of times, five years ago attempted to 21 do such a calculation. And it seems that the outcome of 22 these experiments would tend to verify those estimates which 23 were based on essentially estimating the margins in 24 different steps to the design, which is not --
25 MR. SIESS: What he called a confident lower O m m unis REPORTING SERVICE a arcorri of excellence .
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110-I bound estimate of functional capability. That meant that he 8 2 had fairly high confidence that there wouldn't be any rips 3 I knew, you know, we were or tears. I asked him for that.
4 getting these two or three times and I says, "What's --
5 where's it all coming from?" And he wrote this little thing 6
up.
7 And I think that confident lower-bound estimate of 8 Now, it depends on functional capability is what we want.
9 how much confidence. As I said before, if you take
10 s 115 percent of design pressure, your confidence is fairly L-) ' high. Right? You tested it to that. You started going up 12 first yield. You may be not quite as confident, but you're 13 still fairly confident that at first yield somewhere in this 14 thing it's not going to do it. General yield, that's what
']
vj 15 we looked at on the Sequoyah years ago when we were playing 16 around with this thing.
17 Not quite the same level of confidence, but still 7 ,3 18 fairly high. But the closer you get to this ultimate --
()
19 MR. COSTELLO: Do you want to stop a while7 20 MR. SIESS: -- and we got two tests that tell 21 us that we haven't got any confidence at that level.
22 Look, I think that concludes the presentation on 23 the tests.
24 Let me make a couple of comments. I think that 25 this whole program -- and I'm talking now particularly about
()
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the concrete program -- has been carried out in an 8 2 absolutely superb manner. I can't think of anything that 3 you could have done better or different on it. I think the 4
instrumentation, I think the way you handled the pre-test 5 predictions and got the standard plots and all of that is a 6 tremendous help to everybody. You did a beautiful job all 7 the way through. And I think Sandia is to be congratulated.
8 MR. CLAUSS: First, I do'nt think I'm quite 9
finished with concrete model. I think --
10 MR. COSTELLO: Well, I think you had a --
11 I'll ask this Committe's judgment on this. I think -- we 12 have two more topics on -- two more presentations which 13 speak to your agenda, one of which is was Dr. Weatherby, who
{} 14 15 is going to outline the differences which he found came from different state-of-the-art concrete modeling techniques, and 16 then Dan Horschel, who is going to give you an update on our 4
17 interactions from CGEB on their proposed model test.
18 MR. SIESS: Okay. We're down to the O 19 second -- through the bullet over here?
20 MR. COSTELLO: Yes, sir.
- 21 MR. SIESS
- Okay. That's a good place to 22 stop. Let's go to lunch and try to be back here by 1:40.
23 Okay?
24 (The luncheon recess was taken at 12:40 p.m., to 25 reconvene at 1:40 p.m.)
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AFTERNOON SESSION 2
FRIDAY, JANUARY 22, 1988 3 3 4
4 MR. COSTELLO: This afternoon, we will 5 5 attempt to try and finish off the scheduled morning 6 6 presentation.
7 7 MR. COSTELLO: The'first presentation is 8 8 going to be by Randy Weatherby from the Applied Mechanics 9 9 Division, Sandia laboratory. Dr. Weatherby is going to 10 1 discuss two things with you, one of which, first is the work 11 11 that he did before the test in the nature of what was 12 12 scoping calculation, and also to look at differences among 13 13 axisymmetric modeling technicians which are -- have some
- 1 14 current vogue to_model reinforced concrete.
15 15 Again, the calculations were of the nature in 16 16 which one does an axisymmetric calculation, predicts strains 17 17 and displacement, and then attempts to infer from those 18 18 predicted measurements the behavior of the containment to 19 0 19 estimate whether it might fail.
20 20 Then finally, he's going to go over with you some 21 initial post-test calculations attempting to look at strain l 21 22 22 concentration, the (inaudible) strain concentration that one 23 23 could expect in a location of failure, j24 24 Dr. Weatherby?
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DISCUSSION OF THE CONCRETE MODEL TEST (continued) 3 Pretest Analysis and Comparison With Test Results
- 3. 3 MR. WEATHERBY: As Jim mentioned, I'll just 4 4
.be discussing calculations that were conducted at Sandia.
5 5 I'll attempt to describe what the other organizations did in 6 6 regards to analyzing the 1:6-scale model.
7 7 The topics of discussion here will be, first of 8 8 all, pretest analyses that we've conducted here at Sandia, 9 9 comparisons of predictions and results, post-test analysis 1 to of the piping penetration where we got the large tears you 11 11 saw this morning, and then a little discussion on future 12 12 work. And we'll start off with the pretest analyses.
13 13 The first thing we did in this project is just 14 1{} look at the section of the cylinder wall during the 15 15 midheight and do a very simple analysis and get 16 16 displacements, strains in the liner, reinforcement, concrete 17 17 as a function of pressure for the midsection of the
- 18. 18 containment. This just served as more of a bench mark for I,
1 19 the finite element calculations and it could give us an idea
- 20 20 of what we're looking at.
21 21 Then we moved into doing some axisymmetric finite
' 22 22 elements analyses of the containment structure, using shell i
i 23 23 elements. We did a few using continuum elements.
24 24 Finally, we did an analysis of Equipment Hatch A, 25 25 using 3-D shell elements.
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Primarily what I'm going to be talking to you 3 2 today about is the second item here, the axisymmetric finite 3 3 element using shell elements as far as the response 4 4 predictions go.
5 5 As far as modeling the concrete is concerned, we
'6 6 really looked into two or three different approaches. And 7 7 the first approach here, this just shows the uniaxial 8 8 stress-strain curves used to stimulate the concrete is one 9 9 approach. Here what we have is, we run one analysis where 10 10 3 we use an elastic approach for the plastic model for the end
, 11 V 11 points at that time, the central yield strengths of the
{ 12 12 concrete for tensile fracture strength of the concrete and 13 13 correctional strength of the concrete. And then we have 1 14 another calculation where the tensile strength of the 15 15 concrete seems to be about zero.
16 16 What I did was I made two separate analyses of 17 17 these two different stress strain curves and then pieced 18 18 them together to obtain the predicted response of the model.
' 19 19 So that's Model Type 1. I'll refer to that as a --
20 20 MR. SIESS: Excuse me. Don't go too fast on
' 21 21 that. I'm still trying to figure it out.
22 22 I'm trying to get oriented to the stress-strain 4
23 23 curve the way I look at it. Okay.
24 24 MR. EBERSOLE: Let me ask you a question that 25 25 will reflect my ignorance. In looking at this, do you look i I O 1mww151 1Moisfils
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1 at the deformations on the concrete reinforcing rods and 2
take account of the compressive loads applied as you try to 3
3 stretch the steel?
4 4 MR. WEATHERBY: Yes. And the way it models 5 5 it, the way it's decomposed is, you just add the steel 6
6 stiffness. You have separate models for the steel and for 7 7 the concrete. This is what I'm talking about here is just 8
8 the model for the concrete.
9 9 MR. SIESS: You actually -- when you apply 10 1 - that element, your elements have a separate set of
)
11 11 properties for the steel and the concrete?
12 12 MR. WEATHERBY: Yes, sir.
13 13 MR. SIESS: And the steel is in there as 14 1()nj layers?
15 15 MR. WEATHERBY: Right. It's at appropriate 16 16 location to properly model the flexoral stiffness of the 17 17 wall.
18 18 MR. SIESS: And what about a bond between 19 19 them?
20 20 MR. WEATHERBY: Okay. In the axisymmetric 21 21 calculations, it really doesn't -- well, I won't say it 22 22 doesn't matter whether you assume that there is a perfect 23 23 bond or not. The only location where you would expect a 24 24 difference would be at the basemat and cylinder wall 25 25 junction. Otherwise, the liner is going to be forced to o _ _ _
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follow the displacement or the motion of the wall.
2 MR. SIESS: The difference between the zero 3
3 and the tensile strength case, those are the ones you got 4
4 ~ plotted later?
5 5 MR. WEATHERBY: Right. Maybe it will be 6 6 clearer whenever I --
7 7 MR. SIESS: Okay. I'm just trying to figure 8
8 it, yeah.
9 9 Has anybody made any test where they simply took a 10 1 prism of concrete and ran one bar down the middle of it and 11 M pulled the two ends of the bar to get the effective 12 12 stiffness of that element?
' 13 13 MR. WEATHERBY: Not as part of this test. I 14 1 know that I've seen results from tests like that elsewhere 15 15 but not for this test.
16 16 MR. SIESS: Okay.
17 17 MR. WEATHERBY: Really, in using the -- okay.
18 18 When I use this approach or this model for the concrete, i 19 19 what I was really trying to do was simulate this type of 20 20 behavior. And we ran a set of calculations assuming this 21 21 type of behavior for the concrete, and in this case, what I
, 22 22 have is, I have a descending branch on a stress-strain curve 23 2v for the concrete. And the reason in the tension regime and 24 24 the reason for using this approach is, if you take, let's
" 25 25 say, a panel, a reinforced concrete panel and pull on it, TG 01QlQ Dl Y REPORTING SERVICE a arcd of excellence
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I you calculate the stresses in the steel and you calculate 3
t 2
the total amount of load carried by the steel. Then you can 3
3 back calculate from that a stress -- equivalent 4
4 stress-strain curve for the concrete once you subtracted out 5 5 the steel properly. And what it looks like in the panel is 6 6 that the effect of the concrete slowly decreases until you 7 7 get to about the yield strain of the reinforcement bars.
8 8 Now, this decaying may be --
9 9 MR. SIESS: This is the concrete between 10 1('] cracks?
11 1 MR. WEATHERBY: Right.
12 12 MR. SIESS: Which is a function of bond and 13 13 the spacing and all of these characteristics.
14 1/'l MR. WEATHERBY: Right.
u-15 15 MR. SIESS: Okay.
16 16 And you've got some curves later on and you 17 17 characterize them by no-tension model, cracking model, and 18 18 , elastic-plastic model.
19 19 MR. WEATHERBY: Right.
20 20 MR. SIESS: Could you relate those to the 21 21 three curves?
22 22 MR. WEATHERBY: This is what I refer to as 23 23 the cracking model.
24 24 MR. SIESS: Okay. And the no-tention model 25 25 is just that and the elastic-plastic was the one 500 psi tJ WN NN REPORTlNG SERV 10E a reconi of' excellence
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I tension.
, 2 MR. WEATHERBY: The elastic-plastic model 3
3 consists of piecing two curves together. What I did was I 4
4 used this model until the strains in the steel got to about 5 5 half of their yield. And then I said, "Well, the response 6
6 is going to be closer."
7 7 MR. SIESS: Okay.
8 8 MR. WEATHERBY: This type of behavior like 9 9 that.
10 If-] MR. SIESS: Now, the compression side, is 11 11 this of any importance at all?
12 12 MR. WEATHERBY: There is some compression 13 13 pumped. The highest compression stress is right around the 14 1/. ). cylinder basemat junction.
15 15 MR. SIESS: Because that's very unrealistic 16 10 for compression.
17 17 MR. WEATHERBY: Right.
18 18 Would you take this curve as being more realistic 19 19 of compression?
20 20 MR. SIESS: Yeah. I think it drops off a 21 21 little fast, but 7,000 pound concrete, maybe not.
22 22 Is that first line a straight line? It looks 23 23 curved on mine. The one from the origin up --
24 24 MR. WEATHERBY: This?
25 25 MR. SIESS: Yes.
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MR. WEATHERBY: It's virtually a straight 3
2 line.
3 3 MR. SIESS: It's supposed to be a straight 4
4 line.
5 5 MR. WEATHERBY: I think it's a straight line 6 6 there.
7 7 MR. SIESS: It's not on the plot.
8 8 Is it convenient in your analysis to use three 9 9 straight lines?
10 1p 3 MR. WEATHERBY: Yes.
1~ 11 MR. SIESS: If I use a compressive 12 12 stress-strain curve, I can express out of the break a little 13 13 bit more, so it looks like a lot more like the real curve.
1 14 MR. WEATHERBY: Well, the way it is, is that 15 15 these lines linear curve in the model. So you have a --
16 16 MR. SIESS: You wouldn't be better off with a 17 17 continuous curve?
18.-s 18 MR. WEATHERBY: Sir?
! ( )
l 19 19 MR. SIESS: It wouldn't be just as easy to 20 20 use a continuous expression, just a function of strength?
21 21 MR. WEATHERBY: It would be except that's not 22 22 the way the code was written.
23 23 MR. SIESS: Oh. Maybe that's why I could use 24 24 mine on a (inaudible) 57.
25 25 MR. WEATHERBY: Okay. And associated with O 1mNN N
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the data, the model, is the failure criteria. And these are 2
4 really the three failure criteria used whenever the model is 3
3 nssumed to fail, whenever the stress in the reinforcing 4
-1 steel exceeds the open strength of the reinforcing bars, or 5
5 the equivalent strain in the liner exceeds about 15 percent, 6
6 which is the strain at maximum load, the uniaxial tension 7 7 stress in the liner material. And the third failure 8 8 criteria is whenever the transverse shear -- that's the 9
9 shear that acts across the reinforcement at any location, 10 Ip-} exceeds the shear strength that was -- comes from a paper 11 11 based on some Japanesa test results. We also compared it to 12 12 the shear friction model.
13 13 MR. SIESS: Is there any reason why you 14 expressed the first one in terms of stress and the second 1(v~')
15 15 one in tern,s of strain?
16 16 MR. WEATHERBY: No -- well, there is a 17 17 reason. This 99 ksi came from a test on bars that had 18 - 18 splices in them. The actual ultimate strength of this is l \ )
'19 19 about 105 or 106 ksi. But in tests of bars with splices, it 20 20 turns out that the breaking strength, the average breaking 21 21 strength is -- or rather a lower bound in the breaking 22 22 strength is more like 99 ksi.
23 23 MR. SIESS: Because somebody told me that 24 24 only about two-thirds of the bars failed in the splice.
25 25 MR. WEATHERBY: Right. Still the average of l
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all the results gave a lower value than tests on the bars
- 3. 2 without any splices. This is really a slight reduction.
3 3 MR. HORSCHEL: Actually, wouldn't that be the 4
4 other way around, about one-third of the bars failed in the 5 5 spliced and two-thirds of the bars failed on the bars.
6 6 MR. SIESS: But since the stress was 7 7 completely uniform, I guess you have to take the one 8 8 Okay.
(inaudible).
9 9 Let's see. This is grade 60 steel and 90 ksi as to 10a specified in . . .
U 11 11 MR. WEATHERBY: I believe that's right.
12 12 MR. SIESS: The splice has always exceeded 13 13 the minimum, yeah.
1()
v 14 MR. EBERSOLE: Have you characterized this 15 15 steel in the quantity context? What's it called?
16 16 MR. WEATHERBY: It's A-615 Grade 60.
17 17 MR. SIESS: And the robar?
18 - 18 MR. WEATHERBY: And the liner is 8560.
( }
l h'~' 19 MR. HORSCHEL: No , no, no.
20 20 MR. WEATHERBY: I'm sorry. That's the insert 21 21 plate. And that's the usual material used in Grade --
22 22 MR. HORSCHEL: 414, Grade D.
23 23 MR. WEATHERBY: Grade D.
24 24 MR. SIESS: What's the yield point?
25 25 MR. WEATHERBY: Of the liner?
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1 MR. SIESS: Yeah.
B 2 MR. WEATHERBY: About 50 -- a little over 3 3 50 ksi.
4 4 MR. HORSCHEL: And that's actual.
5 5 MR. WEATHERBY: That's actual. The minimum 6 6 is around 32, I think. 516 is 32.
7 7 In all the analysis, in the equipment hatch 8 8 analyses and all the axisymmetric calculations, my approach 9 9 was to take these failure criteria and rigorously apply them 10 to the loads and strength, calculate it under the element 1{- '
11 '~ 11 calculations. When you do that, these are more or less what 12 12 you arrive at.
13 13 MR. SIESS: In your elastic-plastic you had 1(; 14 two cases, one with zero tension and one with 500; which is 15 15 this?
16 16 MR. WEATHERBY: Okay. What I did was, I 17 17 pieced the two together, as I was trying to use two separate 18- 18 analyses to get the overall response. And I pieced the two 19' 19 together at about 114 psig. Below 114 psig, everywhere the 20 20 concrete had this plateau curve of 500 psi's.
21 21 Then above 114 psig, I assume the concrete --
22 22 MR. SIESS: So essentially you dropped it 23 23 there?
24 24 MR. WEATHERBY: Right.
25 25 MR. SIESS: Dropped it to zero there. Okay.
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And since it failed at the bottom, it didn't make any 8
g 2 difference?
3 3 MR. WEATHERBY: Right.
4 4 I interpreted the results to mean that a hedge 5 5 formed near the basemat at about 170 psig. And this was a 6 6 limit of load type of situation where increasing pressure 7 7 just -- you don't even need an increase in pressure to get 8 8 increasing displacement. When I used the second model, the 9 9 cracking analysis, predicted failure pressure was 180 psig 10 and the mode was just exceeding the ultimate hoop bars in 1{~}
v 11 11 the cylinder midsection.
12 12 MR. SIESS: And I assume the tension on the 13 13 concrete would be zero at that stage?
14 1(~')
c/
MR. WEATHERBY: Right.
15 15 MR. SIESS: Both of those then would be no-16 16 tension in the concrete.
17 17 MR. WEATHERBY: Right.
I 18 MR. SIESS: When you got to the failure 19 19 point.
20 20 MR. WEATHERBY: Well, right. By the time you 21 21 get to 180, that's true.
22 22 MR. EBERSOLE: If it had not leaked at that 23 23 pressure of 180 pounds, but you still retained it by some 24 24 sort of a bladder concept, would it proceed on to a 25 25 catastrophic failure concept?
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MR. WEATHERBY: Well, if you precluded any B 2 type of leaks, then, yes. Well, the other possibility is 3' 3 that the equipment hatch would ovalize and you would have 4 4 leakage through there. And if you precluded anything -- any 6 5 sort of leak, then, sure, probably you would get a 6 6 catastrophic -- or you would get a --
7 7 MR. EBERSOLE: A tear?
ll 8 8 1 MR. WEATHERBY: Not necessarily at 180 psig 9 9 s the liner. That calculation assumes a liner is intact.
1 10 As Dave pointed out earlier, if tears form the 11 11 liner, then the liner seems to be affected at higher 12 12 pressures.
13 13 Difficulties in failure prediction: These are 14 really pretty obvious. The axisymmetric models neglected 1{
15 15 strain concentrations caused by both the penetrations and 16 16 the liner anchorage system.
17 17 The 3-D equipment hatch model that I have, that 18 18 was a three-dimensional model. It did gives us some of the k
19 19 strain concentrations around the equipment hatch, but it 20 20 noglect the line anchorage system and slippage between the 21 21 concrete wall and liner.
22 22 The reason for doing that isn't because -- really 23 23 wasn't because I didn't think it was important. It was 24 24 just -- this was just the first step. And it's all I had 25 25 time to do.
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MR. SIESS: For the first case you've got up 8
i 2
there, you would have gotten the same answer for an 3
3 axisymmetric model with no penetrations, wouldn't you?
4 4 MR. WEATHERBY: For this case here? Right.
5 MR. SIESS: Just a simple membrano analysis 5
6 would have given you that --
6 7 7 MR. WEATHERBY: Of 1807 8 8 MR. SIESS: 180.
9 9 MR. WEATHERBY: You're right.
10 IC^S MR. SIESS: In fact, I think you did that, Q) 11 11 didn't you?
12 12 MR. WEATHERBY: Right. I compared the two.
13 13 MR. SIESS: In one of the earlier versions I 14 saw it, 1/'3 i >
15 15 MR. WEATHERBY: Right.
16 16 The only thing you did -- the way I look at it is, 17 17 if that doesn't apply, you shouldn't do an axisymmetric 1 18 analysis. That just says that fortunately, the weak link is 19 19 in the midsection.
20 20 MR. SIESS: Yeah.
21 21 MR. WEATHERBY: If the weak link had been 22 22 somewhere else, then, that simple calculation might not have 23 23 led to the same result as the full axisymmetric calculation.
24 24 MR. SIESS: What circumstances could you 25 25 think of which would put the weak link somewhere else for p - - . - --
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I hoop stress?
8 2
MR. WEATHERBY: Well, for one thing, if you 3 3 increased the hoop reinforcement, you know --
4 4 MR. SIESS: If you had designed it different.
5 5 MR. WEATHERBY: Designed it differently.
6 6 If there was some sort of a failure associated 7 7 with --
8 8 MR. SIESS: If you varied the hoop stress 9 9 either way from midheight, you could have gotten --
10 i f ~) MR. WEATHERBY: Right. Any place with 11 11 (cough) would have influenced the deformation of the model.
12 12 MR. SIESS: What's the practice in design?
13 13 Obviously if you make an axisymmetrio model, you'll find a l{
15 14 15 lower hoop stress near the bottom and near the top. Right?
Does anybody ever vary the reinforcement that way?
16 13 MR. WEATHERBY: I think the vertical bars 17 17 certainly do change in density as --
1 18 MR. SIESS: What about the hoop bars?
19 19 MR. WEATHERBY: But the hoop bars, a s f s:: as 20 20 I know, are usually constant.
21 21 MR. SIESS: Engineers don't generally like to 22 22 design one horse shades.
23 23 MR. WEATHERBY: The third point that I want 24 24 to emphasis is that even if you predicted strength 25 25 concentrations, there is still some uncertainty in what q ___
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you -- you get strains in the liner. You can accurately 3
. 2 calculate those. But at what point does the liner actually 3 3 tear? There's not a really generally accepted theory for 4 4 doing that. And plus you're complicating the issue by the 5 5 fact that the studs are welded to the liner. The welding 6 6 process itself may degrade the liner properties flat against 7 7 the wold line.
8 8 MR. SIESS: The liner itself has welds in it?
9 9 MR. WEATHERBY: Even the liner itself has 17 T, 10 welds. Although interestingly enough, most of the 1
11 11 failures -- well, they were away from the welds because of 12 12 the studs.
13 13 MR. SIESS: But don't we have a decent theory 1 C~'s 14 of failure that divides the attention just for a plate like L j' 15 15 this?
16 16 MR. WEATHERBY: What generally -- I have a 17 17 viewgraph that pertains to that. It's a common problem in 1 m 18 metal-forming to be able to predict when tears will occur in l
19~' 19 plates under (inaudible) loading.
20 20 Generally what you see, you run tests where you 21 21 vary the ratio of the major strain to the minor principle 22 22 strain. Generally what you get are curves that look like 23 23 this, so that the worst case is a case where one of the 24 24 strains is zero.
25 25 MR. SIESS: Biaxial increases them?
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I MR. WEATHERBY: Hight. But then it increases 3
2 again.
3 3 MR. SIESS: Now, where are we here? What's 4
4 the ratio here? I can't -- two or half? I don't know.
5 5 MR. WEATHERBY: Let's see. For this case --
6 6 in certain areas in the containment, you're at this 7 7 location.
8 8 MR. SIESS: Oh, well, that's in the midheight 9
9 three field. It's 2-to-1, but I can't read the scale. I 1r~~; 10 don't know which way it's --
y) 11 11 MR. WEATHERBY: Okay. This would be --
12 12 MR. SIESS: Where would 2-to-1 be?
13 13 MR. WEATHERBY: Well, of course, it's not 1-( 'i 14 exactly 2-to-1 because the reinforcement is at --
15 15 MR. SHEWMON: Where would 2-to-1 be?
16 16 MR. WEATHERBY: Where would 2-to-1 be? It 17 17 would be a line of the slope of one-half right up here.
1 18 What would that be? There is a 20 -- well, that's 1-to-1.
19 19 I'm sorry. 2-to-1.
20 20 MR. HORSCHEL: You would go the other way.
21 21 MR. SIESS: Right.
22 22 MR. WEATHERBY: Well, no --yeah. So it would 23 23 be up in here.
24 24 MR. SIESS: And, of course, you've got more
'25 25 reinforced (inaudible) than you have vertical center line, n _ _ _ _ _
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- 3. 2 MR. CLAUSS: Actually, you're pretty much in 3 3 a (inaudible), in which you have a large plastic strain in 4 4 the whole cylinder because the loop strains -- you yield 5 5 hoop direction first, and loop strains go very large where 6 6 your (inaudible) strains are still essentially elastic. So 7 7 you have, say, 8 8 2 percent loop straining near the failure point for our 9 9 field and .2 percent in (inaudible). (Inaudible), which is lf")
tj H) about the worst condition you can realize.
11 11 MR. SIESS: Okay.
12 12 MR. WEATHERBY: Yeah, because the uniaxial 13 13 test is over here. It's basically the highest number on 14 1( } this chart.
15 15 MR. SIESS: Uniaxial is?
16 16 MR. WEATHERBY: A uniaxial test has a slope 17 17 of minus a half on here because the strains in the loading 18 \ 18 direction are twice the strain in the direction where
( !
19'~' 19 there's no stress in all directions.
20 20 MR. SIESS: Twice? I thought I saw a ratio 21 21 of .5.
22 22 MR. WEATHERBY: Right, in the plastic range 23 23 where --
24 24 MR. SIESS: Oh, in the plastic range. Okay.
25 25 Count the volumes.
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I MR. CLAUSS:
3 (Inaudible) to be measured at 2
. that material of interrupting 20 or 21 percent for this 3 3 particular material in uniaxial test. In the strain 4 4 condition, we have -- in the containment model, you're going 5 5 to have much plastic floating capacity in the axial. I 6 6 think it's like a factor of two, isn't it almost?
7 7 MR. SIESS: I believe 10 percent.
8 8 MR. CLAUSS: Ten percent, that's right. So 9 9 one thing we noticed right away when we started doing these to if ^S things at the test, this 15 percent criteria we used q) 11 11 starting out is probably not good. It should be more like 12 12 10 percent.
13 13 MR. WEATHERBY: Right.
1/ 14 MR. SIESS: But the test says we can use two.
15 15 MR. CLAUSS: We measured strains higher 16 16 than 2. I'm sure there was (inaudible) in the model they 17 17 were higher than what we measured.
18 18 MR. SIESS: I used 2 as an average.
19 19 MR. CLAUSS: Yeah, right.
20 20 MR. WEATHERBY: 2 percent strain?
21 21 MR. SIESS: Yeah. That would predict the 22 22 test.
23 23 MR. CLAUSS: For this particular combination 24 24 of strain concentrate, that's true.
! 25 25 MR. WEATHERBY: That works very well.
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I MR. SIESS: Now, the question is, how much 3
t 2
can we refine that?
3 3 MR. WEATHERBY: Can we always depend on that 4 4 for any increases or any set of strain concentration?
5 5 MR. SIESS: What kind of test can we make to 6 6 say it's different and how much different?
7 7 MR. WEATHERBY: I'm going to compare these 8 8 models to some experimental results. We really have some 9 9 interesting things that you can see. At least one of the 10 10 's plots on that, as you noted earlier, (inaudible) model, t
)
11 11 And the reason I've included this in here is to 12 12 show how much the properties are dominated by the steel.
13 13 And in fact, in some cases that model hit the best results 14 of any model attempted.
1( ~;
15 15 And all these calculations are just plotted for 16 16 this axisymmetric (inaudible) using different material 17 17 models for the concrete. We'll start off at the -- in the 18- 18 dome area.
19'"' 19 MR. SIESS: Let's see. From that, the 20 20 strains that will be average over seven inches. That was 21 21 your --
22 22 MR. WEATHERBY: Right. The strength of the 23 23 others showed seven inches.
24 24 MR. SIESS: Which is not too far from the 25 25 cracked (inaudible).
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I MR. WEATHERBY: Well, if you -- the cracked B 2 facing would be even smaller, about maybe four and a half or 3 five inches.
3 4
4 And what we have here is -- the green line here is 5 5 the no-tension model for the concrete still in the model.
6 6 But in the dome, of course, there is no compression so the 7 7 concrete contributes nothing there.
8 8 C9 This blue line is two elastic-plastic analyses 9 9 pieced together here.
I 10 MR. SIESS: And that's where it cracked?
11 11 MR. WEATHERBY: 14 and 115. I forget exactly 12 12 the pressure.
13 13 MR. SIESS: That's where the concrete yields?
1 14 MR. WEATHERBY: That's where I assumed it 15 15 vanished.
16 16 MR. SIESS: Oh, that's where you assumed it 17 17 vanished.
16 18 MR. WEATHERBY: And I base that on looking at 19 19 the strain.
20 20 MR. SIESS: And it gets back on the other 21 21 curve -- no, it doesn't get back on the no-tension curve.
22 22 MR. WEATHERBY: No, it doesn't because it's 23 23 still assuming that there's still 10 psi yield strength i 24 24 there. And it's following some sort of yield surface. And 25 25 it doesn't exactly match with the no-tension results. It's O - . . _ _ _ _
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I closer to the no-tension results than the cracking model is.
3 e
2 MR. SIESS: Okay.
3 3 MR. WEATHERBY: Okay. The cracking model 4
4 looks pretty good, but in this area, it appears that the 5 5 real response in the real case, the load carried by the 6
6 concrete drops off faster than what I've assumed.
7 7 MR. SIESS: What strain are you plotting 8 8 that? What measured strain are you plotting?
9 9 MR. WEATHERBY: These are --
10 10 MR. SIESS: No. What measured strains are
)
Lj 11 Il you plotting?
12 12 MR. WEATHERBY: I'm sorry.
13 13 MR. SIESS: Strain gage on where?
1C i ,!
14 MR. WEATHERBY: It's in the inside vertical 15 15 bar in the dome. It's about midway between springline and 16 16 the apex.
17 17 MR. SIESS: And you don't know whether it's IP s 18 at a crack or between crackc?
! )
19' 19 MR. WEATHERBY: Right. There's no way of 20 20 knowing that information.
l 21 21 MR. SIESS: If there's really no bond it 22 22 doesn't make any difference.
I23 23 MR. WEATHERBY: Right.
24 24 In some cases, I'll show you how to compare the 25 25 output from several gages that are in similar locations that l ,- _ - _ - .
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I leads to the same elevations. They're just located at B 2 different (inaudible) anglesaround the model.
3 3 MR. SIESS: What's the probability that the 4
4 gages aren't cracked? Assuming that the cracks occur along 5 5 the bars, are the gages always located between two 6 6 cross-bars?
l 7 7 It would be logical since the bars are touching 8 8 each other and you've only got four inches between them.
9 9 MR. HORSCHEL: The gages are positioned at 10 if 3 different areas, you know, around meridional bars would need
< j 11 11 to be (inaudible), as you viewed it, left to right, front or 12 12 back.
13 13 MR. SIESS: No, but I'm talking about, here's 1F', 14 a bar and here are the bars -- now, here's the bar here and V.J 15 15 here's the bar as we (cough). Is it midway between those 16 16 usually?
17 17 MR. HORSCHEL: Usually, yes. But one thing I 18 18 would like to point out which may add to this discussion.
l19 19 And that is, in protecting our gages during construction, we 20 20 actually plotted that whole thing in an apoxy. So that, to 21 21 some degree, would destroy the bond between the gage and the 22 22 concrete up in that area.
23 23 MR. SIESS: So it were midway between the two 24 24 cross-bars and the cracks formed at the cross-bars you had 25 25 the bond destroyed for two inches in the middle, it's not V(x 1mNNlw REPORTING
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I likely to be much bond on that bar?
3 2
MR. HORSCHEL: Right.
3 3 MR. SIESS: Okay. Thank you.
4 4 MR. WEATHERBY: Okay. I guess -- I'm not 5 5 sure that that would -- even if just one bond were debonded, 6 6 then adjacent bonds would pick up the load there. I'm 7 7 trying to think of --
8 8 MR. SIESS: What?
9 9 MR. WEATHERBY: What I'm trying to thinx of 10 If-} is, if it were divided at that location, would you always U
11 11 expect just to see the steel properties? Is that what --
12 12 MR. SIESS: Let's put it this way. Suppose 13 13 the adjacent bar was not being bonded --
14 1(~'3 MR. WEATHERBY: Right. ;
x_j '
15 15 MR. SIESS: It might have a smaller stray 16 16 than the one you measured.
17 17 MR. WEATHERBY: Right.
1 18 MR. SIESS: Certainly not larger?
l 19' ' 19 MR. WEATHERBY: Right.
20 20 MR. SIESS: What you're getting is the 21 21 strained -- very typical strain at a crack. It's l22 22 conceivable, between cracks the strain would be a little 23 23 lower.
24 24 MR. WEATHERBY: Okay.
25 25 MR. SIESS: On the bar they couldn't have l
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I them. Since you obviously can' t know just what --
2 MR. HORSCHEL: One other thing that may play 3
3 some factor in this discussion, is also, the cracking in the 4
4 dome region is very small. We never noticed large cracks 5 5 throughout the test. And after depressurizing the model and 6 6 inspecting those cracks, they're very difficult to see. You 7 7 almost have to wet the surface, they're that small. You 8 8 don't have any large cracks in the (inaudible) in the wall.
9 9 MR. WEATHERBY: Probably the reason for that 10 l{ is that we're only at about half of the yield strength for 11 '
the bar, so we're not getting a lot of cracked openings or 12 12 cracks opening a whole lot.
l 13 13 This plot shows the radial displacement at the 1(~ 14
) spring line. We can see that the no-tension model J
15 15 cverpredicts the displacement somewhat, joins in at higher 16 16 pressures like you would expect. And the cracking model 17 17 caems to track the results pretty well. In this model, the 1 18 elastic-plastic model isn't too bad, either.
19 19 MR. SIESS: It looks pretty good until you 20 20 get up to the very large displacements.
21 21 MR. WEATHERBY: It should be. Here's what we 22 22 see for the radial displacement at the cylinder midheight.
23 23 And this was one of the ones that we were talking about 24 24 earlier. You do see an upturn in the data sooner than you 25 25 would expect based on even the no-tension model where the
(-]
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l concrete carries nothing. And the only real explanation 2
that I can think of for this is that the seismic bars don't 3 3 pick up as much load as we're expecting them to. Because in 4 4 this sort of calculation, what is assumed is that the size 5 5 of the straining seismic bars will be equal to one-half of 6 6 the vertical strain and the hoop strain. It's just a simple 7 7 more circle transformation.
8 8 That assumes that you have purfect bond and that 9 9 things don't slip relative to one anothar. And it's 1p 3 10 pescible that we're getting some slippage in the seismic
\_/
11 11 bars and that they're not picking up as much load as we 12 12 anticipated.
13 13 MR. SIESS: Are are familiar with some of the 14 1( ) stuff that's been done talking about kinking of bars across 15 15 a crack at an angle?
16 16 MR. WEATHERBY: I've seen a little bit of it.
17 17 MR. SIESS: Dr. Sozen commented on this to 1 18 you at all? He did quite a bit of work on that.
19 19 MR. WEATHERBY: He didn't comment 20 20 specifically with relations to --
21 21 MR. SIESS: You had two kinds of assumptions 22 22 you can make about the deformation of bar across the crack.
23 23 And they lead to quite different results. And I think 24 24 that's what your problem is there.
l25 25 MR. WEATHERBY: Okay,
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l MR. SIESS: There's no assumption that you 2
can make -- simple assumption you can make that is correct.
3 3 MR. WEATHERBY: It's a no-win situation is 4
4 that it doesn't decrease the --
5 5 MR. SIESS: I forget which way it goes now.
6 6 He did a lot of work on it in slabs reinforced group, as far 7 7 as in different directions. And he went into that with 8 8 (inaudible). Do you have the report? I don't think it will 9 9 help you very much, though. He just might have found it 10 1r 3 somehow for you.
C/
11 Il MR. WEATHERBY: Well, here's where things 12 12 that, I think, get interesting.
13 13 This is really the area where all of the other i fT
\/
14 calculations have the most difficulty; and that is, in 15 15 predicting vertical displacements in the cylinder, 16 16 predicting vertical strains in the rebar. And what you see 17 17 is, if you look at the cracking model, this cracking model l10 q 18 has directional properties associated with it. In other j
l 19 19 words, the concrete could crack due to hoop stresses but 20 20 still carry load in the vertical direction.
21 21 While you look at these results, the cracking 22 22 model says all the way out here to 118 or so. There 23 23 shouldn't be any cracks in that stretch. And, yet, if you 24 24 look at the data, they really closely track this no-tension 25 25 model and the elastic-plastic model which doesn't have the o
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directionality associated with it that this cracking model 8 2 does.
3 3 And so I looked at that and I said "Well, what 4
4 happens if we look at all the gages that are in similar 5 5 locations?" So I made a plot of those. There are about 6 6 four different gages here that are plotted.
7 7 What you see is that even down here at real low 8 8 pressures, that all these gages track this no-tension model. ,
l 9 9 Even though the stresses that you would predict from any 10 1(' ,
kind of hand calculation, (inaudible) calculation, would say
_)
11 11 that you had exceeded the tensile strength of the concrete.
l 12 12 MR. SIESS: Excuse me a minute. Was this 13 13 cracked in the structural integrity test? ,
l If't;') 14 MR. WEATHERBY: Not in the vertical 15 15 direction.
16 16 MR. SIESS: How do you know?
17 17 MR. WEATHERBY: Okay. Let's put it this way.
18- 18 It shouldn't have been. That's what I'm going to show on
()
19" 19 the next slide.
20 20 MR. SIESS: When somebody tells me something 21 21 is not cracked, I want to know how they know.
l l 22 22 MR. CLAUSS: No visible cracks.
'23 23 MR. SIESS: Well, that doesn't mean it's not l24 24 cracked.
25 25 MR. CLAUSS: I know. That's why I'm making
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l the statement. But we couldn't see --
2 MR. SIESS: The easiest exploration for that 3 3 curve is that it was cracked.
4 4 MR. CLAUSS: Sure. That's right.
5 5 MR. SIESS: Now, whether you can see them or 6 6 not --
7 7 MR. CLAUSS: Yeah.
8 8 MR. SIESS: Go ahead.
9 9 MR. WEATHERBY: So now we're back to the 10 structural integrity test.
l 17 '
11 11 MR. SIESS: Same thing.
12 12 MR. WEATHERBY: It's the same thing. Even 13 13 way down here -- well, by the time you're up to 28 psi, l1{~'; 14 pretty much on this curve.
x_/
15 15 MR. EBERSOLE: Chet, are you saying that no-16 16 tension curve is actually cracked?
17 17 MR. SIESS: Well, if you will look at the 118 , 18 structural integrity tests, there were obviously some places
(
19"~) 19 where there were no cracks up to about 20, 25 psi. There 20 20 were some that looked like they were cracked at ten, the 21 21 squares. But once they made that test, you see, that's what 22 22 these figures show, is what I'm saying; it got cracked in l23 23 the structural integrity test, period.
24 24 Neve.r assume concrete is uncracked.
25 25 MR. WEATHERBY: I had a little --
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MR. SIESS: Unless that's a conservative 3 2 assumption.
3 3 MR. WEATHERBY: I was wondering. This is 4 4 just some -- an idea I had that possibly what you have is 5 5 you have reinforcements running in both directions. Then 6 6 you have stress applying in two directions. And when you 7 7 develop two cracks, which can develop down here in this 8 8 range -- let me say vertical cracks due to hoop stresses --
9 9 they can form along these vertical bars and cause the bars 10 I F ., to debond from the concrete so that the concrete doesn't add u,J 11 l' any stiffness in the vertical direction of this (inaudible) 12 12 as well.
13 13 MR. SIESS: I think that's an excellent 14 conclusion.
1( ~'3 And I can cite you other tests that would be C/
15 15 (inaudible) improvement.
16 16 MR. WEATHERBY: That would prove this?
17 17 MR. SIESS: I don't know whether you're 1 18 familiar with footing design, but we always permitted a 19 19 lower bond stress in the footings, two-way footings because 20 20 the cracks always formed along the bonds and reduced the 21 21 bond strength along the bar. And I've tested slabs that I l22 22 can go ahead and check my reinforcement spacing by just 23 23 looking at the cracks. And you can see the effects the same
'24 24 way. I think that probably is a good explanation of it.
25 25 MR. WEATHERBY: I was wondering if this would U maNNEW REPORTING SERMCE a recmri of excellence
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1 show up in any of the SIT tests on the full-scale B -2 containments, or if it's a function of the (inaudible) as 3 3 well, even though they're No. 4 bars. And I wasn't sure if 4 4 the No. 18 bar would be less likely to show that much 5 5 sansitivity to cracking by the hoop stresses.
6 6 MR. SEISS: That would be very difficult.
7 7 The (inaudible) would scale, but then your deformation 8 8 size -- the opening in the crack -- if you've scaled you a 9 9 method where the crack should open the same amount in 1 to relation to the deformation rights, the deformation rights 11 11 on bars that related to bar diameter action scale, I think 12 12 it's all linear.
13 13 MR. EBERSOLE: Do the cracks consistently 14 form near the proximity of the rods?
1~}
15 15 MR. SIESS: Yes, at least for the ones that 16 16 are on the outside bars.
17 17 MR. WEATHERBY: Right. In some cases, you 1 18 see the cracks following the seismic reinforcements.
19 19 MR. SIESS: The hoop bars -- the seismic bars 20 20 are on the outside.
21 21 MR. EBERSOLE: That's the bracing, 45 degree.
22 22 night? ,
23 23 MR. WEATHERBY: 45 degrees.
24 24 MR. SIESS: I don't know whether there's been 25 - 25 any -- in the full-scale SIT tests, I don't know whether O - _ _ -_
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they've measured any vertical displacements. They've 2
measured vertical displacement at the peak of the dome, but 3 3 that's not a good mea 7ure to do (inaudible).
4 4 MR. WEATHERBY: You need to stretch the 5 5 cylinder part.
6 6 MR. SIESS: I think that's a good explanation 7 7 for why -- I think it's obvious the cracks are there. And 8 8 I think you've got a good reason why.
9 9 MR. WEATHERBY: But then what that raises is 10 1{>J) the question of -- really, you need to account for that in 11 11 the modeling. And to me, this idea of directional 12 12 cracking -- when you have crack initiators like 13 13 reinforcements isn't a very good approach to the problem. I 14 don't know how you incorporated this affect into the model 1(~~j
')
15 15 unless you just (cough) for the concrete.
16 16 MR. SIESS: Just pay no attention to the 17 17 concrete in the beginning.
1 18 MR. WEATHERBY: Well, I have another plot 19 19 that suggests that that doesn't work in certain locations.
20 20 MR. SIESS: It all depends on what we're 21 21 looking for and what's important.
22 22 MR. WEATHERBY: That's what the next slide 23 23 shows.
24 24 This is the vertical displacement of the basemat 25 25 at the cylinder wall junction. And this shows the (y _ - _ -
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I 144-I calculated displacement is a function of pressure whenever 3 2 you neglect the stiffness of the concrete.
3 3 These two other results show what happens when you 4
4 leave something in for the concrete.
5 5 MR. SIESS: Now, this is bathing in tho 6 6 basemat?
7 7 MR. WEATHERBY: Right.
8 8 MR. SIESS: And it's very thick basemat.
9 9 MR. WEATHERBY: Very thick.
10 1{qx /
MR. SIESS: And it probably hasn't got much 11 11 cracking due to rebar.
12 12 MR. WEATHERBY: Right.
13 13 And this is really important. If you think that 1'} 14 this is what -- how the basemat curls up, then that's really 15 15 going to affect the stresses and strains and the liner at 16 16 the intersection of the cylinder wall with the basemat.
17 17 And I think this is one reason why a lot of people 10 - 18 were predicting failure in the -- at that juncture. Not
- i 1 ~/
19 _ 19 because they used the no-tension curve, but because they 20 20 used their cracking model where they calculated the stresses 21 21 in the concrete. And once they exceeded the strength of the 22 22 concrete, they just threw away the concrete.
23 23 And so what you see in those curves, you see come 24 24 along, you know, fairly a line like this. And suddenly you 25 25 will see a big jump in displacement.
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I MR. SIESS: The strain in the line, are you B
t 2
talking about is simply a geometric strain due to the 3 3 limitation?
4 4 MR. WEATHERBY: Right.
5 5 MR. SIESS: Because this lifts up, that's 6 6 moving out, it increases that angle?
7 7 MR. WEATHERBY: Right. It increases the 8 8 shear force and everything in -- or it increases the bending 9 9 moment at that location as well.
1p~~ 10 MR. SIESS: And you're not for sure?
11 1 MR. WEATHERBY: Not for sure.
12 12 So that's -- but these models turned out to be 13 13 pretty stiff. So the comparison is interesting, but I'm not 1C"; 14 sure what the answer is to resolve the problem.
)
15 15 MR. SIESS: The liner down at that junction, 16 16 if it doesn't have studs welded to it -- it probably doesn't 17 17 make any difference. You get it to yield its yield. It's 1 18 really 15 percent -- it's probably 20 percent there. Not i 19 19 much stress in the other direction.
20 20 MR. WEATHERBY: That's right.
21 21 MR. SIESS: Really, that's (inaudible) as l 22 22 long as you don't put a curve on it.
23 23 MR. WEATHERBY: And the last plot I've got 24 24 shows the (inaudible) inside vertical bars just above the 25 25 cylinder basemat junction. This just shows that if you use 1
1
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the cracking model here, it tracks the flexoral -- the 2
strain resulting from the pressure at that location pretty 3 3 well. And then the no-tension model is considerably larger 4
4 because you have more rotation due to the less stiff -- the 5 5 lower stiffness of the slab on the basemat.
6 6 MR. SIESS: But that's a nonlocal effect.
7 7 That's an effect coming in from the basemat.
8 8 MR. WEATHERBY: Right.
9 9 MR. SIESS: Okay.
10 10 S MR. WEATHERBY: And in summary, at most u) 11 11 locations, the response is dominated by the steel. The only 12 12 exceptions would be when the compressive side of the basemat 13 13 and the basemat itself seems to -- the stiffness of the 14 basemat seems to be strongly dependent on the concrete.
1/ ^S u/
15 15 But elsewhere, the concrete contributes little to 16 16 the stiffness of the model, even in extreme low pressures.
17 17 In the cylinder midsection, the vertical load 18 - 18 carried by the concrete disappears much sooner than you L) 19~ 19 would expect, just based on the -- without considering the 20 20 effect of the rebar's cracked (inaudible) .
21 21 And the basemat uplift again is significantly 22 22 over-predicted when you neglect the tensile strength of the 23 23 concrete.
24 24 Unless there are any other questions, I'll move on 25 25 to another section.
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1 This is the analysis of the piping penetration 3t 2 where we got the large tear in this location right here.
3 3 And what I wanted to look at was what would happen 4 4 if you ignore the anchorage system and ask, "What are the 5 5 strain concentrations in the liner that result from the 6 6 transition from a thin lining material to a thicker insert 7 7 plate." And by looking at this example, that will tell us 8 8 whether the studs were the primary cause of the liner tear 9 9 or whether the studs are just an initiator for a crack. So 10 1p-) you could say that maybe the straw that broke the camel's a
11 11 back.
12 12 So what I did was I constructed just a plane 13 13 stress finite element model that has both the thickened and 1( ~ )
14 and the thinner region model. And in the first cut, I )
15 15 neglected the anchoring system. And I assume there is no 16 16 friction between the concrete and the liner. i 17 17 MR. SIESS: What do you mean by "slip 18' 18 freely"? You don't assume the studs are not there?
)
19 19 MR. WEATHERBY: Right.
20 20 MR. SIESS: Assume the studs are there?
21 21 MR. WEATHERBY: I assume the studs aren't 22 22 there. And what I'm asking is, do you get enough strain 23 23 concentration even without the studs?
24 24 MR. SIESS: Okay. So there's no studs in i 25 25 this case?
l l
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I MR. WEATHERBY: Right.
B 2 MR. SIESS: And no bond.
3 3 MR. WEATHERBY: No bond.
4 4 MR. SIESS: And no friction.
5 5 MR. WEATHERBY: No friction.
6 6 MR. SIESS: Okay.
7 7 MR. WEATHERBY: And then the boundary 8 8 conditions are, you get away from the penetrations and you 9 9 apply the membrane solution, lp N 10 What this is is a plot of the relative slip
~_)
11 11 between -- or at least the magnitude of the relative slip 12 12 between the liner and the concrete wall. What you see is, 13 13 effect, near this thickened plate, this region right here, 14 1(~)
has a thickness of 3/16ths of an inch while this region 15 15 right here has a thickness of 1/16th of an inch. And so 16 16 what the effect is, it's like you put a patch on an 17 17 innertube, more or less, and with the innertube idea being 18-y 18 that the liners, you like blow up a baloon up inside the L .)
19' 19 cylinder expanding.
20 20 Now, right around here, these are where pipes pass 21 21 through the wall. So I would say there is no slip along the 22 22 piping capacitors here. And then there is the no horizontal 23 23 slip that's specified along this boundary and no vertical 24 24 slip specified along that boundary.
25 25 Now, it would be this slippage that would g _ _ _ _ _ _
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1 produce -- that would cause loads to develop in the study, 3 2 if they were there.
3 3 MR. SIESS: Wait a minute. Don't go away.
4 4 I'm still trying to figure that one out.
5 5 M" WEATHERBY: Okay.
6 6 MR. SIESS: At the boundaries, they are 7 7 together?
8 8 MR. WEATHERBY: At the boundaries?
9 9 MR. SIESS: The concrete and the steel are --
1p 3 10 moved together, have they not?
L,)
11 11 MR. WEATHERBY: Al 1g here. At least in the 12 12 vertical direction, they moved together.
13 13 MR. SIESS: All those slip lines are 1/~'s 14 positive.
L-) ,
15 15 MR. WEATHERBY: Right. I 16 16 MR. SIESS: What does that mean?
17 17 MR. WEATHERBY: Well, first of all --
18cy 18 MR. SIESS: If you add them up, I start at
(, )
19 ~' 19 one side over on the left. And when I get to Line C, I'm 20 20 over at the left and moving over. I've jumped to the third 21 21 line where it's uniform.
22 22 MR. WEATHERBY: Okay.
23 23 MR. SIESS: What does that mean? That means 24 24 that -- which is moved relative to which 600 or something --
25 25 600ths of an inch, or does it make any difference?
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I MR. WEATHERBY: By 600ths of an inch. Okay.
3 2 That says that -- well, let me first of all make another 3 3 comment. This is -- in this model, this point is fixed, 4
4 every displacement is measured relative to this point.
5 5 MR. SIESS: Which point?
6 6 MR. WEATHERBY: Well, where these two 7 7 intersect, would be the --
8 8 MR. SIESS: Okay. That's the fixed point.
9 9 MR. WEATHERBY: That's the fixed point on the ip z 10 structure. What I've done is I've plotted the magnitude of
'w) 11 11 the slip effect so it has a vertical component, a horizontal 12 12 component. But it's almost all horizontal, so you could 13 13 interpret these all to be the horizontal component.
1( 14 MR. SIESS: Now, go up from your fixed point.
L-]'
15 15 Aren't those all fixed points of the steel containment 16 16 boundary they were the same, or did you, up that line? Now, 17 17 move up the line from there.
,18 3 18 MR. WEATHERBY: Right.
l ( !
19 19 MR. CLAUSS: You're extending in the 20 20 horizontal direction, but not in the vertical direction.
21 21 MR. SIESS: No, I'm just interested in the 22 22 horizontal direction.
23 23 MR. WEATHERBY: Okay. You get a contour 24 24 here; the contour is here because there is a vertical slip.
l 25 25 I should have brought this, the horizontal slip. It p _ _ . _ - -
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wouldn't have been as confusing.
3 2 In that case, you wouldn't see a contour change up 3 3 here. All these would have zero displacement.
4 4 MR. SIESS: All right. Then as I move over, 5 5 the concrete is moving to the left relative to the liner?
6 6 MR. WEATHERBY: Right.
7 7 MR. SIESS: Because the liner is stiffer and 8 8 the concrete up in the free field is tending to move over.
9 9 MR. WEATHERBY: Right.
10 y 10 MR. SIESS: But by the time I get over to the 11 11 left edge, they're the same again?
12 12 MR. WEATHERBY: Right. By the time you get 13 13 over to the left edge, they're moving with the same 14 displacement.
1(
15 15 MR. SIESS: They're moving together?
16 16 MR. WEATHERBY: They're moving together.
17 17 MR. SIESS: So it doesn't have to go minus to l18 x 18 get a not zero. The displacements -- we're talking about a I )
1V 19 slip -- okay, i
20 20 I think if I drew (cough) integrated and a 21 21 differentiated -- I drew the curve and integrated, that's l
l 22 22 what I should get, shouldn't I, or differentiate?
23 23 MR. WEATHERBY: Go ahead.
l 24 I
24 MR. SIESS: I think I understand.
25 25 MR. WEATHERBY: Okay. You do get the ma::imum t ) 1mNNmW REPORTlNG SERV 10E a recorri of excellence
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1 slip, of course, at the edge of this insert.
B 2 MR. SIESS: Would you trace out line E for me 3 3 so I can see where it goes.
4 4 MR. WEATHERBY: Okay.
5 5 MR. SIESS: Just use your pointer. Does it 6 6 : just loop up to that top E and come back down?
7 7 MR. WEATHERBY: Right. It loops here.
8 8 MR. SIESS: Okay. Fine.
9 9 MR. WEATHERBY: And incidentally, these 10 lp ~ ) displacements are an estimate, complete with fail or stay.
J 11 11 We have some stud tests, and I know the displacements 12 12 wouldn't be the same if I included them down at the bottom, 13 13 which I'm going to do next.
14
, 17 ~ } But still, at least it tells you that the slippage
\.J 15 15 is enough to fill up significant loads in the studies.
16 16 MR. SIESS: A slip of .1 there on Line E l
17 17 means .1 movement?
18- 18 MR. WEATHERBY: Right. That means the wall
(
l 19 ~] 19 has roved over a tenth of an inch more than the one after 20 20 that.
21 21 MR. SIESS: Measure back to this point. At 1
122 22 that point, there should have been a theoretical one-tenth 23 23 of an inch displacement.
24 24 MR. WEATHERBY: Relativo displacement.
25 75 MR. SIESS: Between the two.
U EENNum HEPoliTlNG SERV 10E a recmri of excellence
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3 2 MR. SIESS: If I had a wholo layer, I could 3
3 look down and I could see those (inaudible).
4 4 MR. WE\THERBY: Right.
5 5 MR. SIESS: Okay. Pretty close. That's what 6 6 the stud has to resist? I 7 7 MR. WEATHERBY: Right, it's the shearing 8
8 displacement on the stud.
9 '
9 Well, without -- what do the strains look like?
10 ltJ'~} Are they of a sufficient magnitude to cause failure without
\ ,,/
' 11 11 any studs in the model?
12 12 So these -- I plotted (inaudible) plastic strains.
13 l13 For all intents and purposes, it's the hoop strain. And you 14
' if i t
get a maximum here at the corner of the insert plate there.
/
15 15 It's this rounded edge. But the maximum is only 2.8 percent 16 16 strain, which the stra1n in max load and uniaxial tension is 17 17 15 percent. And even if you take a reduction for a load l 18 ,
18 (inaudible), you can't really suspect failure in this 19'~ ~' 19 location.
1 20 20 MR. SIESS: What's the direction of principal 21 21 strains?
22 22 MR. WEATHERBY: It's roughly pretty much the i
23 23 hoop direction. And I'll show you the next slide which will 24 24 give you a little bit more information.
l 1
25 25 It doesn't tell you the direction.
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1 MR. SIESS: I see.
l 2
f:R . WEATHEREY: But the direction is l
3 3 predominantly in the hoop direction.
4 4 The other interesting thing that I saw in this 5
5 location is that this is the ratio of the maximum principal 6 6 strain to the intermediate principal strain. This is what I 7 7 was talking about before. I didn't think you-all had this 8 8 plot.
9 The other strain, zero.
9 MR. SIESS:
10 IfLi-) MR. WEATHERBY: Far away, in the free field, 11 11 it's going to be more like .14. So that tells you that the 12 12 hoop strain -- the vertical strain is about equal to about 13 13 14 percent of the hoop strain.
14 l 1( ^ ) And as you get in close to this insert plate, it U
15 15 gets much worse, so that right around this location, you're 16 16 almost to the point of strain conditions, where the only 17 17 strains are through the thickness of the sheets and in the 18 18 hoop direction.
19 19 MR. SIESS: Is this the last analysis?
20 20 MR. WEATHERBY: This is the plastic.
21 21 MR. SIESS: Elastic-plastic?
22 22 MR. WEATHERBY: Uh-huh.
23 23 MR. SIESS: At what stage of elastic-plastic?
24 24 MR. WEATHERBY: Okay.
I 25 25 MR. SIESS: How far out on a plastic region l U mNNm REPORTING SERVlOE a reconi of excellence
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I are we?
i l
3 2 MR. WEATHERBY: Let's let this plot pattern 3 3 i
tell us. It tells you that we have -- that the strain is 4
4 about 3 percent.
5 5 MR. SIESS: Oh, okay. That's the equivalent 6 6 plastic strain? I got you.
7 7 MR. WEATHERBY: So you can look on a uniaxial 8 8 curve and roughly go over two and a half, 3 percent.
9 9 MR. SIESS: And this level is what, 145 psi.
10 1p 7 Right?
L) 11 11 MR. WEATHERBY: Right.
12 12 MR. SIESS: Okay. Is that what time down l
l13 13 there is?
14 1( MR. WEATHERBY: Yeah. We raised it one psi 15 15 per second. It does all sorts of funny things.
16 16 And based on this set of calculations, what I had 17 17 an obvious conclusion now, was when the stud anchors are
,18 y 18 neglected, the strains are too small to suggest liner 1 i )
~
l 19' ' 19 tearing. So what that tells me is that the primary 20 20 (inaudible) in the liner was the strain concentration caused 21 21 by the stud anchors. And I have some pictures here. Dan 22 22 showed them a little earlier. But I think the photographs 23 23 bring out 24 24 the -- are a little easier to examine. I only have four
'25 25 pictures so I'll just kind of scatter them around.
p -___
i o RENN m REPORTlNG SERVlCE a arcord of excellence
156-I What you can see in those pictures -- this is
' 2 after the test, obviously. But you can actually see the 3 dimples where the studs are placed at two inches. And you 3
4 4 can see how this relative slip has been a blow to the studs.
5 5 And that's what I -- I really believe now that the studs are 6 6 the primary cause of the failure.
7 7 MR. EBERSOLE: You would have guessed that by 8 8 inspection, wouldn't you? .
9 9 MR. WEATHERBY: Not necessarily.
10 10 ^ >, MR. EBERSOLE: No?
LJ 11 11 MR. WEATHERBY: The problem is that the first 12 12 time we walked into the model, we didn't have all this on 13 13 (inaudible), flashing in and out. When you look at the 1/ ' N 14 tears, you don't really see the studs. And that's when I x) 15 15 started this project. When the photographs came back and 16 16 the lighting was at the right angle --
17 17 MR. EBERSOLE: You could see the shadows 18-s 18 where the studs are trying to hold it.
19'~ 19 MR. SIESS: Randy, looking back at your slip 20 20 plot, that slip is very uniform, all down that vertical 21 21 edge.
22 22 MR. WEATHERBY: Right. There's the secret.
23 23 MR. SIESS: Now, suppose there were no studs 24 24 in there, do you think you could predict where the liner 25 25 would go? After all, you've still got a weld over there.
p - - -
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I It's not too far away. We can't change the material 2
properties.
3 3 MR. WEATHERBY: I don't think I could without 4
4 more test data.
5 5 MR. SIESS: Of course, would it make much 6 6 difference whether you were one at 10 percent strain or 12 7 7 percent strain or 14 in terms of pressure?
8 8 MR. WEATHERBY: Not at that high a level.
9 9 MR. SIESE: What's the curve look like up 10 3 10 there? It's pretty flat, isn't it?
I (,-
11 11 MR. WEATHERBY: Yeah. In fact, the rebar 12 12 probably can't handle more than about 5 percent strain or 13 13 so. But I think then you would be competing with --
14 MR. SIESS: That low?
l{']
V 15 15 MR. WEATHERBY: That's whenever a significant 36 16 number of the studs would probably break. It would be about 17 17 6 percent, is my guess, based on the (inaudible).
18- 18 MR. CLAUSS: You mean the splices, not the 1 : ;
l 19 19 studs.
20 29 MR. SIESS: Splices only get around 5 percent 21 21 strain.
,22 22 MR. CLAUSS: Five or 6 percent strain, yeah.
'23 23 MR. WEATHERBY: At least that would be the 24 24 strain in the bars.
'25 25 MR. HORSCHEL: Maximum loaded bars occurs p __. - --
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l about 6 or 7 percent, maybe a little bit more. (Inaudible) 2 i than that, you reach your maximum load fairly early on about 3 3 6 or 7 percent. And the splices are reducing that slightly 4
4 to your 5 and 6 percent.
5 5 MR. SIESS: And an unspliced bar is still 6
6 only about 6 to 7 percent?
7 7 MR. HORSCHEL: An unspliced bar with a 8 8 maximum load at about 6 to 7 percent strain. It will 9 9 strain -- ultimate strain is probably about what, 15 10- 10 percent, or something like that7 i
J
' 11 11 MR. WEATHERBY: Right. But by then, you're i
12 12 over the hump and things would be happening fast.
13 13 MR. SIESS: Okay.
li'1 14 MR. WEATHERBY: But what I intend to do with
>i 15 15 this, I'm going to try another calculation where I put in 16 16 some strains to model the studs and to calculate loads on 17 17 the studs. That's the next step.
18 m 18 We have some data from stud pull test where wo 1
! 19"' 19 have a stud embedded in the concrete and then a liner plate 20 20 wolded to a stud. And we've pulled on the liner plate and 21 21 measured the force of the (inaudible) curve for the effect 22 22 of that curve, and that we put in the calculations to 23 23 calculate this loading on the studs and see how close we are 24 24 to causing shear failure or --
25 25 MR. SIESS: When you made that test, did you U 1GN19WW l REPORT 119G l SEliVlCE a recmri of excellence
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I carry for failure?
3 2 MR. HORSCHEL: Failure for studs, yes.
3 3 MR. SIESS: What happened?
4 MR. WEATHERBY: Mixed results.
4 5 5 MR. HORSCHEL: It varied. As I mentioned, we 6 6 had some with just one stud on it, some with three and some 7 7 with four. And we had various failures. Some failed in the 8 8 weld itself, some actually sheared the shank of the stud.
9 9 And then in the back were one of the four of the specimens, 1 10 we had one that failed -- two studs failed by weld failure, 11 11 two failed by the shearing of the shank.
12 12 MR. SIESS: When you put more than one stud 13 13 on they don't share the load. They don't share the loads, 1C~'; 14 do they?
)
15 15 MR. HORSCHEL: From what we found, you can 16 16 actually average that ultimate load, and it does average out 17 17 to the --
18 , '
18 MR. SIESS: Yield horizontal.
19 ~ 19 MR. HORSCHEL: But indeed, we could even see 20 20 some rotation on the stud from time to time so we could send 21 21 (inaudible) to get you off one side and not go in a straight 22 22 line.
23 23 MR. SIESS: Did you detect separation between 24 24 the plate and the concrete?
25 25 MR. HORSCHEL: We did do some, and I guess I
(- . - - - - -
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I would have to go look at the report to be sure. But we did 3
2 measure (inaudible) without of plane displacement motion.
3 3 And then there was some, but it was obviously quite small.
4 4 MR. SIESS: And that could oe very hard.
5 5 MR. HORSCHEL: Yeah. It took about 6 6 (inaudible), we're aware of that. But that's all we had to i 7 7 go with right now for our analysis, and we think it's a 8 8 reasonable start. There is obviously some (inaudible) the 9 9 analysis to design some better tests and maybe we can IC'y to further this along a little more. But right now, I don't i
11 11 think we're there. I think we'll need to do some analyses 12 12 with the teuts that we have at hand and see where it can go 13 from there.
l13 14 Chet, can I ask a question?
l 1( ~'s, MR. EBERSOLE:
\ /
15 15 MR. SIESS: Sure.
16 16 MR. EBERSOLE: In the long-run, before you 17 17 get into refining all these things, it's a little bit like l 18 3 i
18 the thermal hydraulics. What's the goal? Is it to ensure i
19 '" 19 you'il have a program failure, as you wish it, or to have a 20 20 failure like the wonderful one-horse (inaudible), all over 21 21 the place at once? I think it's the former, which you got 22 yf accidental.
23 23 MR. WEATHERBY: Well, from my -- go ahead.
24 24 MR. COSTELLO: Well, I was going to say --
1
'25 25 just a thought.
7,, _ _ _ _
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I I was going to suggest that in the long-haul, I 3
i 2 think that the goal is more like the former, that if you're 3 3 sure that you know how far you can go from (inaudible) or 4 4 anything, then it's like any such strategy developed around 5 5 that or of which that factor (inaudible). Then it would 6
6 make sure we understand why these things happen and how they 7 7 happen.
8 8 MR. EBERSOLE: You can be sure of that.
9 9 MR. COSTELLO: So you can't project them to to 1{ -} different full-sized containments.
11 11 MR. EBERSOLE: Yeah, so you can be sure 12 12 really of the former objective.
13 13 MR. COSTELLO: Yes.
14 l e' '~ ') MR. EBERSOLE: Okay.
J 15 15 MR. COSTELLO: As long as you've got a 16 16 reliable method.
17 17 MR. WEATHERBY: The last slide. This is what 18-) i 18 I anticipate doing in answering the questions people ask me.
19 '~ ' 19 The way I look at it at this point, I would focus all my 20 20 efforts in the future -- most of my efforts on trying to 21 21 characterize leakage due to liner tearing because that looks 22 22 like a very important problem to consider now.
23 23 And in dcing that, I think you have to distinguish 24 24 between two things. One is the initiation of the tears in 25 2s the liner. And that involves being able to predict stresses (O m0N10aN REFoliTlNG SEliVlCE a reconi of excellence
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1 and studs and very local details. But if you do initiate a B 2 liner tear, then you have to know how that tear -- how does 3 3 it grow. In some cases in the model, it appears that the 4 4 tears didn't grow at all, like around the equipment hatches.
5 5 They've just -- well, they grew in small (inaudible) and 6 6 quit. The matter of the tear around the insert plate grew a 7 7 long distance. And that's related -- bably related to 8 8 the fact that there's a uniformed condition along the edge
'9 9 of that insert plate.
I 10 So it seems to me that one could distinguish 11 11 between different types of liner tears, depending on the 12 12 locations where the tear occurs.
13 13 There is some that are likely to grow and others 1("T 14 that are likely to stay as pin holes once they form. Both V
15 15 of these problems are very complicated. It's not an easy 16 16 answer or an easy puzzle to solve it because any approach is 17 17 going to require a lot of testing to really validate the 18 technique.
18-)
19 / 19 MR. SIESS: Randy, since the initiation is 20 20 going to occur presumably where there's a high stress, 21 21 what's the probability that it will propogate into a region 22 22 of lower stress?
23 23 MR. WEATHERBY: If there's a large stress or 24 24 strain gradient -- you know, stress changes very rapidly 25 2rs with position. And it could be that the tear will just grow O - - -
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REPORTING SERVlOE a accord of excellence ,
163-I' a very small density. It may take a lot of pressure to make 2
it grow any substantially.
3 3 MR. SIESS: Because everything you've done 4
4 now suggests that. You get these high stress 5 5 concentrations. They're not very -- they're high, but 6 6 they're not very wide.
7 7 MR. WEATHERBY: Right. That's the liner --
8 8 you're talking about the stretched concentrations caused by 9 9 2
the stud?
1 10 MR. SIESS: Well, even in the liner those 11 11 things were not very broad. And that wasn't enough to do 12 12 it. So to get the initiation, you've got to put the stud 13 13 in?
14 MR. WEATHERBY: Right.
l{}
15 15 MR. SIESS: And that's got to be very local.
16 16 MR. WEATHERBY: Right.
17 17 MR. SIESS: And once you get away from the 18 3 18 stud, you're going to be back into that lower stressed area.
19Y) 19 And unless you've got a very poor ductility material, it 20 20 really shouldn't propogate.
21 21 MR. WEATHERBY: But it looks like, at least 22 22 the way I interpret the test and based on the leak 23 23 measurements and what not, that we did reach a critical
! 24 24 condition in the test, so we had a tear that formed -- maybe 25 25 more than one tear -- along the edge of that -- on the edge l
O raamwnw REPORTING SERV 10E a wcorri of excellence . _ .
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. . _ 164-1 of the piping penetration.
2 MR. SIESS: Yeah, but I --
3 3 MR. WEATHERBY: But there was a certain 4 pressure at which this tear suddenly grew from a fairly 5 5 small tear to a very long tear that ran along the edge of 6 6 that insert plate.
7 7 MR. SIESS: Well, why wasn't it one, two, 8 8 three, four, five, six, seven, eight tears (cough) stud?
9 9 That E lino, that whole area is uniform and slipped. All
'1 10 right. And all the studs would be getting about the same 11 11 load. And it wouldn't be surprising at all with the same 12 12 stress probably, and the same stud loads that you would get 13 13 five or six tears to connect it up.
14 Iq ) I think what you're saying -- and I'm not saying 15 15 you shouldn't do what you're doing -- but I just think the 16 16 probably, the dynamic crack propogation, and that's good.
17 17 You know, once you get away from that (inaudible) plata, you
, 18 g 18 really drop off.
19 O 19 MR. WEATHERBY: Right. I guess what I'm 20 20 thinking of is more, when will the crack that's in this 21 21 stress-field caused by the stiffner plate we want to
' 22 22 (inaudible) go to something that's on the same length as a 23 23 stiffner plate.
4 24 24 MR. SIESS: Gets away from the stiffner l25 25 plate.
I l
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1 MR. WEATHERBY: If I had a small tear due to 3 2 a stud --
3 3 MR. SIESS: Yes.
4 4 MR. WEATHERBY: -- (inaudible) a day. Then
'S 5 if I increase the pressure, at what point will that small 6 6 tear i
7 7 is -- or is there a pressure level where that small tear 8 8 suddenly takes off and grows along the edge of this stiffner 9 9 plate and (inaudible) in the stiffner plate.
10 1 MR. SIESS: You know, I would suspect from 11 11 the leak rates, the different pressures, that you might have t 12 12 had seven small tears here that gradually grew and connected I
i 13- 13 up.
1( 14 MR. HORSCHEL: Yeah, if you look at the plate
, 15 15 below it, I certainly fear that there is at least two that 16 16 look like they're ready to capture the liner. And, you '
17 17 know, certainly you can have both of those start at the same 18 18 time and eventually join up.
(
l 19 Another thing I find interesting if, if we look at 20 20 the shape of that E line that he has drawn up twice, it's 21 21 almost analagous the way that tear kind of rounded the 22 22 corner of that insert plate, kind of showing that, in my 23 23 mind, the crack was going from a high slip area to a low 24 24 slip area.
25 25 MR. SIESS: And you would really like for it
)
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I to run a little bit. You might want it to run far enough to t,
j 2 get the heat rate up to pressure.
3 3 MR. WEATHERBY: But that was -- we have made 4
4 this place larger to go to. ,
5 5 MR. SIESS: We can put the studs in at an 6
6 inch apart (cough) a nice long one that would reduce the 7 7 pressure.
8 8 MR. WEATHERBY: What kind of tests point did 9
9 I have in mind.
10
, 10~T MR. BENDER: That's the other slide.
V 11 11 MR. WEATHERBY: It depends on which problem l 12 12 we are talking about.
13 13 MR. BENDER: I'm just looking at the future 14 work.
1( ) Let's talk about the first one, predicting the 15 15 initiation of liner tears. What sort of thing is the 16 16 initiation of liner tears?
17 17 MR. WEATHERBY: Well, first of all, we 18-s 18 haven't really formulated the specific (cough).
(]
19") 19 MR. BENDER: So it needs to be the developed?
20 20 MR. WEATHERBY: Right. These are merely 21 21 categories. I can think of some (inaudible) that I would 22 22 like to follow up on. But what we need to do is plot some 23 23 designs, some tests to go along with those.
4 24 24 What I have in mind as far as the (inaudible).
25 25 You then look at the problem of the stud in the liner O inawwnw REPORTING l
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because I think that's where the strain concentration comes 3 2 from. And once you get that forces on the stud, then you l 3 3 can do -- probably look through the thickness of the liner 4 4 and you can look at the strain concentrations due to bending 5 5 and shearing of the studs.
6 6 MR. SIESS: You've got a problem there, 7 7 though. You can take your pull-out or push-out tests, as it 8 8 was, you know, the tests you made and you get some idea of a 9 9 load slip characteristic from the stud, and that will give 10 , 10 you the shear forces of the stud.
Is 11 11 MR. WEATHERBY: Right.
12 12 MR. SIESS: You're going to have a little l 13 13 more difficulty trying to find out how much (inaudible) is 1
1(^) (/
14 on the line.
15 15 MR. WEATHERBY: That's the problem.
i 16 16 MR. SIESS: Because that shear force is going 17 17 to be concentrated very near the bottom of the stud. It's a I
'18 18 flexible -- it's a dial action.
19 O 19 So it will be down near the bottom, and if it's a 1
20 20 tenth of an inch off or two-tenths of an inch off, makes the 21 21 factor 2.
l 22 22 As it starts, you can simply assume the plastic 23 23 moment of the stud going into the plate.
24 24 MR. WEATHERBY: Okay.
25 25 MR. SIESS: That's not an upper bound, O _ . -
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' I though, because there is a weld on the bottom of that that 2 gives you a little extra area.
l 3 3 But you can take the plastic off of the stud just 4 4 above the weld, and that would be a place to start. That's 5 5 the only way I would know to do it. And I've tested my 6 6 channel shape-shear connectors with strain gages on them, 7 7 but I don't know how to put -- you can't do it on the studs.
8 8 It won't work.
9 9 MR. BENDER: Let's talk about the second item 10 up there, propagation.
1Q"3 V
11 11 What do you have in mind there?
12 12 MR. WEATHERBY: Okay. First of all, this is 13 13 the (inaudible). And in a field fraction again, is still 14 very -- it's not that well developed.
1% ) And the first thing 15 15 we would have to do is, we would have to go back in and try 16 16 to get fracture (inaudible) for the material which we don't 17 17 have right now, the liner material. That would be a set of 18 18 tests that we would have to do.
19 19 Then your approach here would be to assume the 20 20 surface wall size that might be scaled by stud diameter. So 21 21 you would assume that a very small tear develops due to the 22 22 stud, if that tear is going to extend, just outside of the 23 23 strain field or the stud -- or the area where the stud 24 24 influences the strain, and then you ask yourself at what 25 25 pressure will that size of flaw grow or begin to grow into a O ,aamw, ant REPORTING SERV 10E a wconi of excclience
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1 larger flaw, whether it will grow stably slower or faster.
B 2 MR. BENDER: Is there any background data 3 3 that you can use as a frame of reference?
4 4 MR. WEATHERBY: There are some cracks that we 5 5 found (inaudible).
6 6 MR. EBERSOLE: Isn't it the fourth bullet, 7 7 which is, if you arrest pressure buildup by establishing a 8 8 leak, well at what point would it reclose?
9 9 MR. SHEWMON: The steel will never reclose.
-1 10 MR. EBERSOLE: Not the steel, but the 11 11 concrete structure reclose to a reasonably tight 12 12 containment.
13 13 MR. WEATHERBY: I don't know that it really l
1( 14 ever would.
15 15 MR. EBERSOLE: I've heard it claimed that it 16 16 would.
17 17 MR. BENDER: Well, if the (inaudible) is 18 18 going up through the concrete structure itself, that might 19 19 be an interesting question.
20 20 MR. SHEWMON: I have another question.
' 21 21 MR. BENDER: The pressure doesn't necessarily j 22 22 (inaudible) of job.
I 23 23 MR. EBERSOLE: That's where it goes after the i24 24 first of the liner.
25 25 MR. SHEWMON: That last point is that there 1
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I is no pull resistance to the concrete, isn't it?
3
't 2 MR. EBERSOLE: No. It's a natural quench.
3 3 MR. WEATHERBY: That would be something I 4
4 would say that the flow resistance of the concrete would not 5 5 be that important in the calculation, just as a first guess.
6 6 I would be trying to calculate the open area to the crack.
7 7 MR. EBERSOLE: Is there enough resiliance in 8 8 the rebars after it's been strained to suggest that we 9 9 reclose the weld in the concrete.
1 10 MR. WEATHERBY: You can go out to the (cough) 11 11 and look at the structure today and you can see, in fact, in 12 12 the pictures that you have of the tear, you can soo that 13 13 there is quite a gap in this liner.
1 ~s 14 MR. SHEWMON: But that also buckles. The
)
15 16 question is what gap is there in the concrete?
16 16 MR. WEATHERBY: Yes. Well, you can see quite 17 17 large cracks in the concrete.
18 3 18 MR. SHEWMON: If you want to move away gas.
)
19 19 MR. WEATHERBY: Well, I don't know how to 20 20 estimate that.
21 21 MR. EBERSOLE: In actual concrete pressure 22 22 vessels like they have on (inaudible), that's the, I think 23 23 one retrinsic claim, isn't it.
24 24 MR. BENDER: That's a prestressed concrete.
25 25 MR. EBERSOLE: That's true; that's true, (p>
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I MR. BENDER: And this is designed to be held B 2 closed by the --
3 3 MR. EBERSOLE: That may be the best kind to 4
4 build.
5 5 MR. BENDER: Well, that's a relevant 6 6 argument. Whether the prostress containment may have some 7 7 different kind of --
8 8 MR. WEATHERBY: Well, I think in the 9 9 prestress containments, I just got through looking at one 10 1F~] for another exercise; there, the prestressing, once you K '
11 11 overcome the prestressing, it's just like reinforcement in 12 12 many respects. By prostressing you really don't gain any 13 13 ultimate capacity.
1 14 MR. BENDER: If you take the concrete out of 15 15 the plastic, what have you got if the concrete remains in 16 16 compression, up to the point of line, then you could 17 17 consider.
18 - 18 MR. COSTELLO: But typically, Mike, about 125 i h~'; 19 percent or 140 percent of design pressure is enough to 20 20 unload --
21 21 MR. WEATHERBY: Right.
22 22 MR. BENDER: I don't disagree with that.
23 23 MR. COSTELLO: So you know, when we're 24 24 talking bubble design pressure, we're already in the 25 25 reinforce mode again.
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i 171 MR. BENDER: It's a fairly complicated 2
subject, but my reason for that question has more to do with 3 3 just trying to get some impression of what the ongoing 4
4 program might be, how long would the test program be, how 5 5 much effort might be involved, and what do we do with the 6
'6 information after we've got it? :
7 7 MR. COSTELLO: Let me try and (inaudible) for 8 8 '
a second because there is more, we're not alone in this 9 9 undertaking, allowing the EPRI sponsor -- most of the EPRI 1 to sponsor's work at ANATECH is concentrated on minor 11 11 (inaudible). They are currently working on a policy of --
12 12 set of hypotheses which we hope to have available in the-13 13 spring, and taking together, Randy has attempted to get some 14 14 of the scoping packages with the calculations, independent
' 15 15 calculations for (inaudible) company, and then we would be 16 16 able to better formulate some test program to check the 17 17 hypotheses.
! 18 18 But, again, the question of prestressing, I don't 19 19 want to be premature, but even for those reinforced 20- 20 containments which have contiguous anchorage, there is 21 21 reason to speculate that if the stud here is the greater of 22 22 two factors the concentrations, the more ridged anchorage 23 23 would do a better job of concentration than with the stud 24 24 and the embedded (inaudible) will pin that piece of liner 25 25 even better.
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1 MR. BENDER: Based on what I saw of the test 3
c 2
out there, I could easily envision looking at different 3
3 kinds of stud patterns for new container designs. But for 4
4 existing containers, I don't know that I know what to do.
5 5 MR. COSTELLO: I think we also have to --
6 6 another thing we have to look at in the pattern of our test 7 7 program, is the population of anchorage designs.
8 8 (Inaudible) to arrange for first we have to have some sort 9
9 of that would hypothesize what is important. You know this 10 10'-} kind of anchorage system should be more sensitive than it is L;
11 11 or this should be very concentrated.
12 12 MR. BENDER: Is EPRI trying to do that? It 13 13 seems to me that's what they ought to be doing.
14 1('i MR. COSTELLO: Their ANATECH work is being C/
15 15 focused on theories for minor tear initiation. And even, I 16 16 believe, some propagation, I think, the focus is fairly on 17 17 initiation. It may well, I hope, suffice the purpose. It 1 18 seems that a small delta p is required to get you going and l19 19 then the initiation will suffice.
20 20 Thank you, Mr. Weatherby.
21 21 To finish off the presentation on concrete j
22 22 containments, we have a short presentation from Dan 23 23 Horschel, who has been interacting in our behalf with the 24 24 Central Interstate Charity Generating Board on their 1
'25 25 proposed model test for a model of the Size Well B U, , WNNN REPORTlNG l SERVlOE a record of excellence
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I containment,-which is a great similarity to a Stumps designs 2 '
in the U.S..
3 3 To give you a little history on it, you have a 4
4 back and forths about whether the vallidity of K about 5 5 The side that decided, whether has a (inaudible) or not.
6 6 which did not include the CEGB, but decided that is was 7 7 prudent to do a test on the model containment prevailed.
4 '8 8 CEGB acquiesces its condition of license, but then faced two 9 9 possibilities; one, do a test which would meet the minimum 10 1 commitment that they have which is to show the strength of 11 11 the shell to be at least twice the design pressure to be 12 12 consistent with the PCRB requirements -- this was the 13 13 licensing requirements they have on themselves -- or to do a
' 1( 14 little more and put a liner in and actually look at failure 15 15 modes. After some going back and forth, it begins to look 16 as if they will concentrate on the minimum test.
- 16 That being 17 17 the case, we don't see as being a payoff for us in 18 18 participating. However, we are likely to participate in 19 19 their undertaking to about the same level as they 20 20 participated in the concrete model.
- 21 21 MR. BENDER
- That will be a prestress 22 22 containment.
t 23 23 MR. COSTELLO: It will be a prestress 24 24 containment, unless they change their minds on the liner; 25 25 unless they change their mind again on the liner.
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17.5-1 MR. SIESS: Who's going to design it?
3 2 2 MR. COSTELLO: The Taylor Woodrow/McApline 3 Dan's been over there interacting with them 3 combination.
4 4 recently, last fall, and he's going again shortly. He will 5 5 give you what he knows today.
6 6 MR. SHEWMON: What is "PCRV"?
7 7 MR. COSTELLO: PCRV, prestress --
8 8 MR. SIESS: Fort St Vrain.
9 9 MR. COSTELLO: Or more precisely, British gas 10 And the Minimum 2 Factor was attached to the l{- ~
reactors.
11 11 design of both the British prostress reactor vessels and 12 12 they all were tested, model tested, all the designs heve 13 13 model tests to show that. The licensing argument was will, 1 C'N, 14 youve got to do the same for a prestress containment for 15 15 light water reactor.
16 16 MR. SIESS: Have they got a rationale for not 17 17 putting the liner in?
18 18 MR. HORSCHEL: It really goes back to what 19 19 Jim was saying about the strength. Since the liner is 20 20 included in the design as a strength member, they say it 21 21 (cough) from the test. That's usually their --
22 22 MR. SIESS: They are going to build them with 23 23 a liner, but not test them with the liner?
24 24 MR. HORSCHEL: Exactly. Because when you put 25 25 the strength of the containment, the code doesn't allow you
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I to use the liner as a strength bearing member.
2 MR. SIESS: Then -- their code or our code?
3 3 And they are only interested in strength, not leakage?
4 4 MR. HORSCHEL: In fact, 14: seems like a 5 5 large (inaudible) this is attached just to manifest that 6 6 they can go two times beyond the design pressure without 7 7 that liner. They also, of course, do want to get help 8 8 (cough). At first, they had two times of design pressure 1
9 9 and that seemed to be very important to them.
10 10 % MR. SHEWMON: Two times beyond or two
> (_/
' 11 11 kinds --
12 12 MR. HORSCHEL: Two times design pressure.
13 13 MR. SIESS: What was it? What did you change 1( 14 there?
I 15 15 MR. HORSCHEL: I said two times beyond but I l
1 16 16 meant two times --
1 17 17 MR. EBERSOLE: You said without the liner.
i 18 18 Right?
19 O 19 MR. HORSCHEL: Right.
20 20 MR. EBERSOLE: They don't allow the liner to
, 21 21 contribute to the load.
22 22 MR. SIESS: We don't either.
I 23 23 MR. HORSCHEL: That's the same as it is in
'24 24 the United States. The liner is considered the normal load 25 25 bearing member.
O --
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MR. SIESS: That's part of our conservatism.
3 i 2 MR. HORSCHEL: That's considered the natural 3 3 containment. We're talking about --
4 4 MR. EBERSOLE: How do they propose to seal 5 5 the concrete?
6 6 MR. HORSCHEL: They'll be using a rubber 7 7 bladder and they'll be pressurizing using a hydrogen -- l 8 8 water.
9 9 MR. EBERSOLE: That has it's advantages, you 10 10 ~x know.
() 11 11 MR. HERSCHEL: H20.
12 12 MR. EBERSOLE: They won't use rubber in real 13 13 life, surely. What will they use?
14 1 C'~) MR. SIESS: They'll use a liner, v
15 15 MR. EBERSOLE: Oh, okay.
16 16 17 17 FUTURE WORK ON REINFORCED AND PRESTRESSED CONTAINMENTS Prestressed Containments l18 3
(
18 1
, 19 19 MR. HORSCHEL: We'll get into this point a 20 20 little bit later.
l 21 21 So why don't I just start. First off, you always 22 22 hear of the CEGB, that's Central Electric Generating Board.
l23 23 They are sponsoring this test. It's designed by Nuclear 1
24 24 Design Associates and it's a joint venture between Taylor 25 2s Woodrow and McAlpine. The construction and testing of the
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1 prostress model will be done by Taylor Woodrow.
i3 2 They do have a peer review group. This is a list 3 3 of those people. Carl Lomas, who's the chairman of the 4
4 Sizewell "B" Positive Management Team, PMT.
5 5 There's also Peter George, he's part of the 6 6 sizewo11 asa positive Management Team.
7 7 There's Dave Philips from the UKAEA; James Irving 8 8 from the Independent Inspection Agency.
9 9 Paul Divjak, the Project Manager from Bechtel, 10 Sizewell "B" Project Management team.
10-)
v
. 11 11 There's also Dick Crowder from the Nuclear Design
,12 12 Associatee.
13 13 And there's myself, from Sandia National Labs.
14 Some of the features of the containment model:
1/ ~3 It
(_/
15 15 is a scale model of Sizewell "B".
16 16 Along those lines, they also felt that scaling the 17 17 Sizewell "B" was more important than following codes, so if 18,i 3 18 there is any overlap of those two things, they'll probably 19 19 lean toward the scaling of the Sizewell "B".
20 20 It has one equipment hatch, two personnel 21 21 airlocks. Both of those are over-designed penetration l22 22 covers, so that they will not leak. Keep in mind, there is 23 23 no liner in here, so it's just the (cough) concrete and they 24 24 have some type of bearing plate around those to hold them 25 25 into place.
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There is no external or internal structures 8
i 2 represented.
3 3 They use scaled steel and force rather than using 4 4 a 1:1 bar replacement and tendon replacement.
5 5 The tests will be conducted hydrostatically and 6 6 they, of course, have thickened the basemat due to the 7 7 (inaudible) malfimestamia of the gravitational forces and 8 8 not including the internal force, the internal structures.
9 9 Due to the scale, which is 1:10, they are mixing 10 1C'N the model with concreto.
N) 11 11 MR. SHEWMON: What is "scaled steel areas" 12 12 mean?
13 13 MR. SIESS: It's really force, 14 li 'T MR. HORSCHEL: 10 inches is a full-size model V
15 15 on the scale. This scale doesn't have one, 3c has one 16 16 square inch. Okay. Say, on a full-size containment, you 17 17 might have 10 bars and the model might have two bars. So ig-) 18 they would have 10 bars and each one is a square inch; it's
\ )
19 '~' 19 not on this model.
20 20 MR. EBERSOLE: So that cracks won't scale.
21 I 21 How tall will this thing be?
22 22 MR. HORSCHEL: Overall height is about 23 23 23 feet not including the (inaudible).
24 24 MR. EBERSOLE: So the hydraulic oil is 25 25 inconsequential, o -_- __-
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1 MR. HORSCHEL: (Inaudible) pressure fails, 3
2 2 the higher pressure that you go, it doesn't (someone talking l
3 3 Your hydrostatic head will give you at same time).
4 4 approximately 10 psi from top to bottom.
5 5 MR. EBERSOLE: That's not enough.
6 6 MR. HORSCHEL: It depends on where it fails.
7 7 If you were at 150 psi, 10 psi difference isn't too much, 8 8 where if it falls at 50 psi, 10 psi is more significant.
9 9 Here's the overall dimensions of the containment 1 - 10 model. Here you can see the basemat. They do have it
~
11 11 sitting on top of the pedastal so they can get to the 12 12 original (inaudible) test is so slow.
13 13 Here's one of the personnel airlocks.
1/ ~T 14 Nominal wall thickness is .13 motors in the
\
.)
15 15 cylinder wall and .1 is your dome.
16 16 Inside diameter is seven and a half feet; using 17 17 radius seven and a half feet.
18 3 18 The top view of the containment, here you can see
\
19~] 19 the three buttresses from the prestressed. How they come 20 20 up, again, you can see the buttresses, but also the two 21 21 personnel airlocks and the one equipment hatch. This is a 22 22 stretchout of the cylinder. Again, the two personnel 23 23 airlocks, the equipment hatch, and the layout of the three 24 24 buttresses.
25 25 One thing that I think is important is whether 1
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they decided to connect the reinforcing steel. The Sizewell 3
2 "B" uses cold swaged splices much as we used in our scale 3 3 model, reinforced concrete model.
4 4 For this model, however, they will weld 5 5 reinforcing steel together, rather than using the splices.
6 6 Sinse this is an ultimate strength test, we've recommended 7 7 that they reconsider the cold swaged splices, but it seems 8 8 like they will weld them.
9 9 MR. SIESS: Dan, how much does the rebar 1p 3 10 contribute to the (cough).
V 11 11 MR. HORSCHEL: I guess, off the top of my 12 12 head, I really don't know.
13 13 One of the things that I was somewhat surprised at 14 1(^T is when you lose the preload. Preload only takes you to V
15 15 about one to one -- excuse me -- somewhere around 1.2 to 1.5 16 16 of the design pressure, so you're really relying quite a bit 17 17 on the reinforcement to get you up to that two times --
18 18 MR. SIESS: Well, we do that, too. Our 19 19 prestress usually is designed to get you up to the SIT 20 20 without cracking.
21 21 MR. HORSCHEL: That's true. This is very 22 22 typical of a Bechtel design and --
23 23 MR. SIESS: Rebar doesn't usually contribute 24 24 that much, 10 or 15 percent maybe, I think.
25 25 MR. HORSCHEL: Okay.
/^.
L,) lanNNmi liEPoliTlNG SmiVlCE a wconi of excellence -----
182-I MR. SIESS: So really, it's 90,000 stuff, 2
whether it makes 90,000 or 95.
3 3 MR. HORSCHEL: But my understanding is, 4
4 there's always been a problem with welding high yield 5 5 reinforcing steel.
6 6 MR. SIESS: We could get grade 60 in this 7 7 country that is well able. I mean, I assume they could get 8 8 some, too. We got an awful way of attaching two bars 9
9 together. They don't like welding, but butt welding and so 1p 3 10 forth.
(' /
11 11 What are they going to learn from this that you 12 12 couldn't learn from the Alberta test?
13 13 MR. HORSCHEL: I have to speak somewhat from 14 1('~') the cuff on that. I believe in the Alberta test, they V_)
15 15 didn't do a very good job of handling things. For example, 16 16 the walls were disproportionately thick and things such as 17 17 that.
l18 18 MR. SIESS: I know, but you can analyze it.
l 19 19 MR. HORSCHEL: Yes, but here --
20 20 MR. SIESS: This isn't a prototype, this 21 21 isn't a proper model anyway. It's a simulation. You have
- 22 22 to analyze it. Doesn't have a liner; doesn't have the steel 23 23 in the right place.
24 24 MR. CLAUSS: I think the major question was l25 25 that there was very little instrumentation of the test in
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1 Canada.
2 MR. HORSCHEL: That's not really true. They 3 3 had quite a bit on that. It was probably about 300 gages in 4
4 the wall, such as that, that's close to what we had planned 5 5 on this.
6 6 But I think the real question, in answer to your 7 7 question, goes back to what Jim said when he introduced the 8 8 top of this list; it's almost imposed by the NII, not the 9 9 CEGB to test the model.
I f N 10 Since the VCRBs had to do it, MR. SIESS:
i s-
'11 11 this has to do it.
12 12 MR. COSTELLO: That's it.
,13 13 MR. SIESS: But then they couldn't look at i1 14 Canadian and the Colony and you know.
15 15 MR. COSTELLO: CEGB's first argument was, it 16 16 was proven technology from the states. Ergo, they don't 17 17 need to do the same kind of test as probably for VCRV's.
18 18 (All talking at once.)
'19 19 MR. HORSCHEL: If you have a fullsize 20 20 Sizewell "B," they use the channels instead of the liners.
21 21 MR. SIESS: I'm sorry. That's a ridiculous 22 22 test.
23 23 MR. WARD: How are going to get license?
24 24 MR. SIESS: We aren't going to learn a thing, l25 25 unless something peculiar happens.
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184-I MR. COSTELLO: I guess I can speculate that 3
c 2
what we will get out of it is a chance to get out of it, 3
3 absent surprises. Absent surprises that are not a result of 4
4 something straining in this, peculiar to the model.
5 5 MR. SIESS: Is this a Bechtel prestressing 6
6 scheme?
7 7 MR. HORSCHEL: Yes.
8 8 MR. SIESS: What model, frozen type?
9 9 MR. COSTELLO: SNPPS.
10 10 ~', MR. SIESS: I'm not sure. Which was SNPPS7 J
11 II MR. COSTELLO: Callaway, for sure. There was 12 12 supposed to be five of them.
13 13 MR. SIESS: No --
14 MR. WARD:
1( } In Texas, 15 15 MR. SIESS: Yes. But three buttresses, what 16 16 about over the top?
17 17 MR. HORSCHEL: I think that's just a 18 18 (inaudible) thing. They don't need them all the way to the l19 19 top.
20 20 MR. SIESS: No, no. The early designs had a 21 21 ring gear that was a separate set of tensile bands, a
,22 22 verticle tensile anchored at the top.
l 23 23 MR. HORSCHEL: The reason those tendons go 24 24 all the way across the top --
) 25 25 MR. SIESS: That's the (inaudible) design o - _ - _ .
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2 MR. COSTELLO: You have to speculate that, 3 3 you know, if they go through the tests at this form about 4
4 it, all we'll get out of it is the ability to see how well, 5 5 you know, the method that have been shown in the SIT's to 6 6 TRAC and unloading well enough to 115 percent.
7 7 MR. SIESS: Are they don't scale the steel 8 8 properly in the buttresses, or are they going to mess around 9 9 with this?
10 MR. HORSCHEL: They're trying to scale l{^')
11 11 Sizewell "B."
12 12 MR. SIESS: I know, but in terms of bars and 13 13 number of bars and so forth.
14 MR. HORSCHEL: It won't be the same number of 1( ~')
1 15 bars. You just --
16 16 MR. SIESS: The Canadian model failed to 17 17 buttress in the anchorage.
18 18 MR. HORSCHEL: And that's one thing we want 19 19 to instrument a little heavier on this model, is to --
20 20 MR. SIESS: Looks like it would be sens.itive 21 21 to have the steel (inaudible) was made.
22 22 MR. HORSCHEL: I agree.
23 23 MR. SIESS: Interesting.
24 24 MR. SHEWMON: Their sealing for the 25 25 cross-sectional area of the steel will be the same?
l n _. _ -
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186-1 MR. HORSCHEL: Yes.
3 2 MR. SHEWMON: Not the surface area?
3 3 MR. SIESS: Right.
4 4 MR. SHEWMON: They hope by next section to 5 5 yield --
6 6 MR, SIESS: They're scaling on forces. The 7 7 forces of will be right. How they put them in there --
8 8 MR. SHEWMON: My questions was it fails by 9 9 net-section collapsed, not by pulling out?
10 1 ~ $
MR. SIESS: Yeah. There shouldn't be any 11 11 pulling out.
12 12 MR. BENDER: Not figuring on anything 13 13 failing, that's just pretty much saying whether it takes 14 1/'] (inaudible).
x_/
15 15 MR. SIESS: It's only going to go up to the 16 16 design level and quit, 17 17 MR. HORSCHEL: Well, they do find one until 18 18 they get some type of failure in your own model, 19 19 MR. SIESS: Okay. They do have a war.
20 20 MR. HORSCHEL: It will depend heavily on the 21 21 (inaudible).
22 22 MR. BENDER: Right. Hydrostatic.
23 23 MR, SIESS: You're going to get 10 people to 24 24 predict it.
25 25 MR. HORSCHEL: I don't think they have been l
l
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187-1 quite as successful as we have.
3 g 2 MR. WARD: Are you going to predict it?
3 3 MR. HORSCHEL: We're going to try and locate 4 4 it, but people, I guess we're going to try to have that 5 5 select an analyst, so I'm not sure when this will occur, as 6 6 far as this program is concerned in their schedule. We'll 7 7 be relying on some predictions, whether we protest or or 8 8 post-test remains to be seen. We would like to do protest 9 9 but it's getting people to do that.
10 10-] MR. BENDER: Excuse me. One other question V
11 11 about the size. Is this designed to the ASME code?
12 12 MR. HORSCHEL: Well, it's actually the 13 13 British standard, but a large part of that is the ASME code.
1C 14 MR. SIESS:
) Is 1.5 load factors and --
15 15 MR. HORSCHEL: So I'm not that familiar with 16 16 theirs. I know they adopt the ASME code for the most part.
17 17 I think they have their own little quirk to take care of 18 18 there.
19 19 MR. COSTELLO: And one of those quirks is an 20 20 additional requirement of minimum twice pressure.
21 21 MR. SIESS: Minimum of what?
22 22 MR. COSTELLO: Minimum of two times the time 23 23 pressure.
24 24 MR. BENDER: As opposed to one and a half.
25 25 MR. COSTELLO: Right. The ultimate o >
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1 requirement, ultimate strength of the containment which is 3 2 twice the design.
3 3 MR. SIESS: We have a little more than one 4 4 and a half, in fact, one and a half divided by 29 gives you 5 5 165, I guess, not counting the seismic. They won't have the 6 6 seismic margin in it. I assume they don't have a seismic.
7 7 MR. COSTELLO: It's just that that 8 8 (inaudible) does have a slippage statement about ultimate --
9 9 which is what they are being --
10 n 10 MR. SIESS: Oh , boy. In other words, they
()
11 11 are wasting money. i 12 12 MR. HORSCHEL: Going on to the concrete used 13 13 in this model, it will be mixed at the site and they are 1('N 14 looking both for tensile and compressive properties and will V
15 15 try to match those as best as they can. l l
16 16 MR. EBERSOLE: What is "micro-concrete"? j 17 17 MR. HORSCHEL: That's where you really don't 18-s 18 have a full-size aggregate. It's really more of i
19 ' ',/ 19 (inauduible). It's the more that you have in your mix.
20 20 MR. EBERSOLE: No superfine aggregate, is it?
21 21 MR. SIESS: No. You don't scale the 22 22 aggregrate (inaudible). We used it for years before anybody 23 23 named it. We used to call it mortar.
24 24 MR. HORSCHEL: Mortar mix is very common.
25 25 MR. SIESS: Deep level concrete.
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I They will take the cylinders MR. HORSCHEL:
2 for ASTM pressure testing and some of you may even be aware 3 of the British (inaudible); they will be taking some samples 3
4 4 from us and and testing those for our analyses.
5 5 MR. SIESS: They still make some split 6 6 cylinder tests?
7 7 MR. HORSCHEL: Yes. They plan on doing that.
8 8 MR. SIESS: That's the way the buttresses go.
9 9 MR. HORSCHEL: They will also do some beam 1 10 bending tests (inaudible).
11 11 Some specimens will be temperature-matched cured.
12 12 Before we began building this style of the model, at Taylor 13 13 Woodrow, they do have a fairly advanced concrete testing 14 x 14 laboratory there. They may ask you to cut into your copy of
( l 15 15 the model used on the heaters or whatever is required to 16 16 move temperature.
17 17 MR. EBERSOLE: What part of O/A do they use 18 s 18 to get a consistent repeatable mix all the time, as they
( )
19 19 make it?
20 20 MR. SIESS: Good standard practice, Jesse.
21 21 MR. HORSCHEL: That's really it. They've 22 22 written up some specs from the model and they are trying to 23 23 minimize any parameter that would affect the strength of the 24 24 concrete, or really what it is, is just (inaudible) building 25 25 contair, ment .
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I MR. EBERSOLE: There is nothing funny about 2
them testing the batches for --
3 3 MR. HORSCHEL: Not as a slump (inaudible).
4 4 If you're at work, you're going to have to test the first 5 5 part of the concrete also.
6 6 Whenever you work with a scale model, even when 7 7 you don't have 1:1 bar replacement, some areas get very, 8 8 very dense with all your tendons running through, all your
.9 9 reinforcing steel, plus instrumentation of things like that.
10 1 It's very hard to properly place the concrete, so slump is 11 11 very important; as will be the ability to consolidate the 12 12 mix vell and not have it segregating when you start 13 13 vibrating it to consolidate it.
14 Again, along those lines, if you plan on using 1(
15 15 some mockups of congested sections, just to make sure they 16 16 can place the mix properly as (inaudible) concrete, that's 17 17 obviously going to be very important. So you're going to 18 s_ 18 find out (inaudible) if they start prestressing it if they 19 O 19 didn't (inaudible) follow the concrete.
20 20 As far as the specimens are concerned, I guess 21 21 there is always some controversy when working with the scale 22 22 model. Should you use scale specimen or full-size 23 23 specimens, particularly when you're talking about wall sets 24 24 that are thin as these. You weren't allowed to have a i
25 25 cylinder -- some people argue that you weren't allowed to
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1 have a cylinder bigger than the three sections of the wall, B
t 2
So I have bolted six by 12 in the cylinder and some l
3 3 micro-specimens will be used.
4 4 MR. SIESS: How small is the micro-specimen, 5 5 two by four?
6 6 MR. HORSCHEL: We haven't really decided on 7 7 the size yet.
8 8 MR. SIESS: That's what we always used to do 9 9 it when I did it.
10~ ; 10 MR. HORSCHEL: That does seem appropriate for LJ 11 11 the wall thickness that we have and the size that we have.
12 12 The last viewgraph: They really started the 13 13 design about October of last year.
14
'1F^3 Supposedly, last I heard, they were starting the
.)
15 15 support tests in November.
16 16 I've just received the design packet from them in 17 17 January, which means that if the construction shou 1C. follow 18( 3 18 through, it would be after about February. And the rest of 19) 19 the schedule there, August should be the start of testing; i20 20 and December, complete testing and report the results.
,21 21 It's obviously a very optimistic schedule; whether l22
, 22 they meet it remains to be seen.
l 23 23 I'll be impressed if they actually get that model l24 24 bui.lt and start testing in the February to August time l25 25 frame. I think that is the most critical section.
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1 MR. SIESS: Are you afraid they'll show you 3 2 up?
3 MR. HORSCHEL: Yeah.
3 4
4 (Laughter) 5 5 No, we always have (inaudible) getting up here.
6 6 We have so much more instrumentation and things like that.
7 7 But, it's an impressive schedule.
8 8 MR. SIESS: That's what you can do when you 9
9 go after a private contractor.
10 10w) i MR. HORSCHEL: I'm not supposed to respond to 11 11 that.
12 12 (Laughter) 13 13 In all honesty, I guess I should say a couple of 1('x_/l 14 things about that. As far as design specs and things like 15 15 that, before we can pour a concrete model, we had to do all 16 16 that from scratch. We've actually given them a lot of the 17 17 information that came from our testing and it has helped 18- 18 them to some degree. I looked at the specs that they wrote 19 .J 19 for this and you can see that they mirror a lot of the 20 20 things that we have, our testing plant, and things like 21 21 that. So we really helped them cut down, at least to some 22 22 degree, beforehand. We've made a lot of the trial and 23 23 errors, if you will, of instrumentation. We've given them 24 24 suggestions for what we've used and what worked well for us.
25 25 So it really has helpea them to some degree shorten it up
,y __.
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1 their schedule and minimize some of that. Hopefully, they B 2 won't use it without any thought and hopefully they will 3 3 cover the bases that we didn't cover that are in their 4 4 model, but they did gain a benefit from our testing program 5 5 here.
6 6 MR. SIESS: Thank you.
7 7 MR. COSTELLO: Okay. I guess I would like to 8 8 have the committee, in the sense to view their wishes on 9 9 what to do between now and what you perceive to be a time to 1 1(~j 10 (inaudible).
U 11 11 It is -- the remaining presentation on the work on 12 12 (inaudible) of Sequoyah of closing out the steel containment 13 13 question in the sense of doing an application to an actual 1('~'j 84 plant and follow-up by some presentations on the ongoing xj 15 15 work on penetrations. We could quite easily defer the 16 16 discussion of the (inaudible) study on seismic capacity of 17 17 containments because, quite frankly, given our '88 budget 18 ,
18 reductions, we are not going to proceed at the pace we i )
19 19 thought we were going to be; and one of the things that gets 20 20 pushed off downstream is any question on seismic capacity.
21 21 MR. SIESS: I thought the analyses showed l22 22 that seismic capacity was awfully high.
l23 23 MR. COSTELLO: Generally speaking, yes.
l24 24 MR. SIESS: What about the Japanese test, did 25 25 they put theirs on the shake table yet?
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l I MR. COSTELLO: No, but they had have some 2 (inaudible) analysis, some (inaudible) loads on good size 3
3 models.
4 I thought they were going to 4 MR. SIESS:
5 5 build a pretty good size model and put it on the shake 6 6 table.
7 7 MR. COSTELLO: They have had one steel 8 8 containment model on the shake table.
9 9 MR. SIESS: Steel.
10 MR. COSTELLO: Steel.
10- ;)
11 11 MR. SHEWMON: That's a racking --
12 12 MR. COSTELLO: Model.
13 13 MR. SHEWMON: One diminsional shape, or just
~'
- 14 squeeze it cgainst it?
1{G 15 15 MR. COSTELLO: Most likely to give you the 16 16 lateral load effect of the --
17 17 MR. SIESS: Is that a simulated seismic with 1 18 the automatic equipment that --
19 19 MR. COSTELLO: Yeah.
20 20 MR. SIESS: They've got a -- make a static 21 21 test that has feedback that simulates the input from an 22 22 earthquake.
23 23 MR. SHEWMON: They rock it in some way.
24 24 MR. SIESS: No, no, just lateral loading.
25 25 MR. SHEWMON: So they push on it on one side?
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I MR. SIESS: Push / pull.
2 MR. SHEWMON: And it's held on the bottom by 3 3 friction or something. That was what I was trying to ask.
4 4 MR. SIESS: They do it in a programmable 5 5 system that stimulates the seismic (inaudible) and then 6 6 (inaudible) depends on the response for the two cycles.
7 7 MR. WARD: Why is that? Because we'll be 8 8 involved in inertia if things aren't right, or what?
9 9 MR, SIESS: Well, you just don't want to push 10 if ') it statically. You want to represent the --
\.s' 11 11 MR. WARD: I mean, why isn't it just done on 12 12 a shake field?
13 13 MR. SIESS: Well, it was a lot cheaper to put l
i fN 14 it on a shake table, but this is a hell of a lot bigger one.
G 15 15 I believe they're testing 6x30 building with this system.
16 16 MR. COSTELLO: But if that's your preference, l l
17 17 we can do that. l 1 18 MR. SIESS: I think just put the seismic last 19 19 any way. I have to leave. I would think that what I would 20 20 put next on priority would be the study on penetration. We 21 21 haven't heard much about that at all.
,22 22 MR. COSTELLO: Okay. That's fine, if that is l23 23 your preference.
l24 ?4 MR. SIESS: And then I sort of leave it to 25 25 you as to whether we take up this steel containment stuff a pcNNw REPORTING SERV 10E a recoirl of excelicnce
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l after that, finish up on this steel containment.
2 MR. COSTELLO: Thaak you.
3 3 MR. SIESS: We haven't heard much on the 4
4 airlock and seal bellows --
5 5 MR. COSTELLO: On containment penetration 6 6 activities, we have first Dave Clauss, talking about 7 7 Personnel Airlock test.
8 8 MR. SIESS: This question on applicability of 9 9 model tests that's on typical full scale containments, where 10 Ip- ) did you put that in your list?
I <.;
11 l 11 MR. COSTELLO: Well, I sort of th1ught that's 12 12 what we were touching all along, but let me look . . .
I 13 13 When we're done, have your schedule presentation l
l 10~'N 14 speak some more to it.
()_
15 15 MR. SIESS: That's the 64-dollar question, of 16 16 course, that we did talk about it all along, but let's come 17 17 back to it before we're through.
I 18 18 MR. COSTELLO: Okay.
- 19 19 MR. SIESS
- And before we go any further what 20 20 are you going to do with that?
21 21 MR. CLAUSS: I need to use the slide l 22 22 projector.
23 23 MR. SIESS: Would anybody like a short break i 24 24 before we . . .
25 25 MR. CLAUSS: That's probably appropriate.
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l I
It's going to take me a few minutes to get the slides ready.
3 2 MR. SIESS: Let's take 10 minutes here.
3 3 (Off the record) 4 4 5 5 CONTAINMENT PENETRATIONS 6 6 Investigation Of The Leakage Potential 7 7 of a Personnel Airlock 8 8 9 MR. CLAUSS:
9 I'm going to be talking about 10 10 recently concluded experimental program that we had that was L,
11 11 designed to look into leak potential of personnel airlock.
12 12 The reason that we want to look at the airlock, it 13 13 has been identified in previous studies the potential --
if ) 14 okay. Thank you.
LJ 15 15 (Fixing the projector) 16 16 MR. SIESS: It's cockeyed, Paul, but it's 17 17 still all right.
1 - 18 MR. SHEWMON: You can tilt your head that 19'" 19 much.
20 20 MR. SIESS: Yes.
21 21 MR. CLAUSS: The airlock has been identified 22 22 as a potential failure mode for containment. And as part of 23 23 this overall objective then to analyze the performance of 24 24 containment, you need to be able to evaluate each potential 25 25 failure mode containmen: to determine whether or not it's
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1 controlling. So that's the basic objective in looking at 3
t 2 the airlock.
3 3 There are a few studies that singled out the 4 4 airlock. The first was INEL, internal adminstrative study 5 5 that was documented NUREG-1037 which tried to predict leak 6 6 areas from various penetrations. The specific example here, 7 7 in Zion, the estimated leak area was 5.36 square inches at 8 8 134 psig.
9 9 MR. SIESS: That was for something that IC- 10 started off tight?
11 11 MR. CLAUSS: That's for something that 12 12 started off tight; and what they were saying, there was 13 13 enough separations on the ceiling surfaces on the airlock to 14 produce a leakage.
1 1/ ~ 3<
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15 15 MR. EBERSOLE: Well, tell me, some of them 16 16 are sealed and pneumatically inflated.
17 17 MR. CLAUSS: Right. I guess I should have l18-x 18 said that at the very outset. The airlock classes that I
( ;
19'~' 19 want to focus on here are those organic seals which rely on 20 20 pressure seals rather than inflatable seals. Brad Parks 21 21 will be talking a little bit about the inflatable seals for 22 22 test programs we have that will be, the value and potential 23 23 and those types of thing.
24 24 The second study, the Oregon survey, Oregon did a l
25 25 comprehensive survey of the penetrations that were in
(
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I various containment in the U.S. And they went through a B 2 fairly rigorous figure of merit type analysis trying to 3 3 evaluate the potential of different penetrations. And 1 4 4 think in their list, (inaudible) No. 1, and this airlock was 5 5 like No. 2.
6 6 So again, to address the concern that the airlock 7 7 as a potential leaking pattern.
8 8 We have heard that the full size airlock canceled 9 9 nuclear unit and tested to hypothetical severe accident to ifq environments.
i' 11 11 Okay. So the airlock is essentially one that was 12 12 built for service in the nuclear plant. I believe it was 13 13 Callaway Unit 1 or Unit 2 it was originally intended for, 14 that plant was supposed to be canceled.
if 1 L) 15 15 There were no (inaudible) made on the block for 16 16 testing and that's what you're seeing here, these various 17 17 penetrations are for man way, man-way access and 18-, 18 instrumentation to pass through, and so forth.
)
l 19'" 19 But the dimensions of the airlock are basically 20 20 10 feet in diameter. And the overall plant is about 20 21 21 feet. The next slide has more: Ten foot in diameter, 20 l22 22 feet long. The sleeve thickness is about one inch thick 23 23 near inner door, and that tapers down to 5/8 inch for most 24 24 of the length and towards the outer door.
1
'25 25 The bulkheads are stiffened flat circular plates, U maNNmw REPOliTING SERVICE a record of excellence
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l of course, cut out for the door. The plate thickness is 2
about one inch on the bulkhead.
3 3 The door size is 42 inches by 80 inches, and there 4
4 is a real stiff frame around the door which consists of webs 5 5 and flanges; these plates are quite hefty, as you can see 6 6 there.
7 7 The doors themselves are also flat plate with 8 8 grooves for the double, grooves for the double body to be 9 9 on. And then, again, that's the door itself with the 1F~g 10 stiffeners.
L .)
11 11 MR. SIESS: What kind of pressures are these 12 12 things designed for?
l13 13 MR. CLAUSS: This particular airlock is l
14 l 1('~)
RJ designed for 56.
15 15 MR. SIESS: 56.
16 16 MR. CLAUSS: I'm sorry. 60.
17 17 This is just an outer view of the airlock and here 18 3 18 it's being loaded into the test chamber.
1 19 Go ahead to the next. This again is the unit test l 20 20 chamber, it just gives you an idea of the size of the door 21 21 opening there. Go ahead. Okay.
22 22 What we had here was a high temperature /high 23 23 pressure test. And the objective of the test again, as in 24 24 all our tests, is to generate data that we can use to 25 25 validate analytical methods.
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In this particular test, I put a strong emphasis 3 2 on trying to produce conditions necessary to generate 3 3 leakage. So we got some information on what the appropriate 4 4 limit state criteria were. Again, this is a caveat I think 5 5 we have in all our tests. We're not trying to take this 6 6 test in the design of airlocks. This is a relatively recent 7 7 vintage airlock and it has (inaudible) of different 8 8 stiffener details. So, with the results I'm going to show 9 9 you, shouldn't be taken and used generically. It really has 1p- 10 to be a case-by-case basis.
, i 11 11 MR. SIESS: Are you pressurizing the inside 12 12 of this, which would be the outside of the natural 13 13 containment, just the door you're testing. Right?
l1('m 14 MR. CLAUSS: No, we didn't test -- I think L]
15 15 I've got a slide that may show the test arrangement. Well, 16 16 let me go ahead and describe it real briefly.
17 17 There were a number of allocations made for the 18 . 18 block, cover for testing; we did pressurize the inner door f )
19' ' 19 on the surface that we would see pressure in an actual 20 20 containment accident. The way we did that was to build a l 21 21 pressure vessel that we attached to the ir. side edge of the 22 22 sleeve so that there is essentially about a foot long length
'23 23 cylinder and then a hemispherical dome, which was used to
'24 24 pressurize the inner door. There is also (inaudible) was to 25 25 add a leak-tight bottom chamber. And this facilitated the U,m maNNmw REPORTlNG f SERVlCE a recorri of excellence
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I measurement of leakage passed the outer door. Leakage would Sc 2 go into that chamber and then reroute it through piping past 3 3 (inaudible) so we could measure leakage in the event we saw 4 4 any.
5 5 There is also similar leakage in the inner door 6 6 where if there is any leakage passed the inner door, there l 7 7 is some type of shroud that gathers that leakage over the 1
8 8 door frame and the leak is directed through some piping, 9 9 through flow meters, so that we can measure the actual leak 10
- 1 h i rate.
As ,/
11 11 This is just one of the things that we did try to 12 12 increase, if you will, the potential for leakage. We wanted 13 13 to age the seals. If the seals were not aged, they've got lq ' , 14 so much springback that even with large deformation you 15 15 would never see leakage.
16 16 And the seals are subject to some high temperature 17 17 and radiation aging of the surface. We did attempt a very
'18 s 18 severe condition, it's the IEEE specs, which is based on a l \ )
l 19'" 19 40-year surface life. In reality, these seals have just l20 20 been changed, about ecery five years.
,21 21 So this is a very severe condition that perhaps I
!22 22 would never be seen in actual containment.
23 23 MR. MARK: What's the basis of saying that 30 24 24 degrees Fahrenheit equals 200 Mrado?
25 25 MR. CLAUSS: Well, we did an analysis and o _ _ ._
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l based on some data from (inaudible), and we looked at the 2
parameter seal performace called compression set retention, 3 3 which is basically just a measure of how much the seal can 4
4 spring back after being deformed and subject to these types 5 5 of conditions. So you deform the seal a certain amount and 6 6 you subject it to 300 degree Fahrenheit and 200 megarads, 7 7 which is the IEEE specs, then you can measure a disclaimer 8 8 called compressive set retention.
9 9 MR. MARK: You're merely measuring something 1( 3 10 analogous to embrittlement.
U/
11 11 MR. CLAUSS: Pardon me?
12 12 MR. MARK: You're measuring something 1
13 13 analogous to embrittlement.
14 1(L,/') MR. CLAUSS: Yes, it's analogous.
15 15 MR. WARD: Loss of --
16 16 MR. CLAUSS: It's analogous to that.
17 17 So at any rate, we've --
l18 ,
18 MR. SHEWMON: The way that's worded; it
( )
19 19 sounds like you aged with high temperatures during 20 20 radiation. Is that right?
21 21 MR. MARK: No, they didn't do any radiation.
! 22 22 MR. CLAUSS: Let me start over.
1 23 23 The IEEE specs are the 40-year --
'24 24 MR. SHEWMON: I understood that.
25 25 MR. CLAUSS: Okay. I'm just trying to lay it n _ _ _ _ .
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l out from the start. Excuse me.
2 The IEEE specs call for both thermal and radiation 3 3 aging. In our test, we could only do thermal aging because 4
4 of the size of the seal and the size of the fixture, it was 5 5 impossible to do radiation.
6 6 What we wanted to do was come up with a thermal 7 7 aging that was equivalent to the radiation, they were aging 8 8 in the IEEE spec.
9 9 Now, to do that, you have to decide what is the to parameter I'm going to try to make equivalent. And the g
i 1(G 11 11 parameter that seemed to affect leakage most highly is 12 12 compression set retention.
13 13 So, we had, from compressed rate data, a pretty 1/ ~' 14 good idea of what the compression set retention is for this 15 15 type of material when it's subject to the IEEE specs. So 16 16 what we wanted to do and then was to achieve that same 17 17 compression set retention and thermal aging and what we 18 3 18 found through some -- there is a modem called (inaudible)
)
19 19 equation that was used for this. It's not that great of a 20 20 model, but it was the best that is available. Using that 21 21 model, we came up with 330 degrees Fahrenheit.
22 22 MR. EBERSOLE: I thought you just said a 23 23 30 degree difference was the radiation effect.
24 24 MR. CLAUSS: That is true, but it gives you 25 25 the same compression set retention as both thermal and I
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I radiation aging.
8 t
2 MR. SIESS: That's the same kind of 3 degradation?
3 4 That's right.
4 MR. CLAUSS:
5 5 Okay. There was significant damage to the seal.
6 6 This is a shot of the seal before the aging; the double 7 7 "dogears" (inaudible), and dogears refers to these. It's 8 8 essentially a cross-section, they look like little ears from 9 9 that. Those actually provide the ceiling.
"3 1("'s Now the cross-section was significantly changed in 11 11 the photograph after aging. Essentially these dogears were 12 12 extruted and the seal became essentially a gasket. You can 13 13 see there is this lip between (inaudible) that scooted out 14 1C 'i and that's what is going to form the ceiling seemingly at
'.)
15 15 this point.
16 16 Now, it's a pretty gross change but we decided 17 17 this was a worst case scenario and we wanted to see what 1 18 would happen to the seal. I think there are some more 19 19 photographs; you can see it. You can see the kind of damage 20 20 that this created when the bulkhead was opened or the door 21 21 was opened causing the bulkhead damage and this material 22 22 here.
23 23 MR. SIESS: That test was intended to find --
24 24 reproduce the degradation that would occur following an 25 25 accident. Right?
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1 MR. CLAUSS: Yeah. That includes the 40 3 2 years service life plus LOCA if there was some accident.
3 3 MR. SIESS: If it were just normal service, 4 wouldn't you expect the seal to be replaced when it looked 4
5 5 like the one you had?
6 6 MR. CLAUSS: If it was just normal service, I 7 7 would take it into account.
8 8 MR. SIESS: Well, you showed a considerable 9 9 change of shape of the seal.
' 1 p- - 10 MR. CLAUSS: Right.
O 11 11 MR. SIESS: Now, that could be taken care of l12 12 by maintenance and replacement.
13 13 MR. CLAUSS: Sure.
14 MR. SIESS: I don't think you would leave a
' l?')
(_/
15 15 seal in there if it looked like that, so it would have to 16 16 be --
17 17 MR. CLAUSS: Oh, of course you wouldn't leave 18 18 the seal in if it looked like that.
19 19 MR. SIESS: 40 years is really not as 20 20 important as the accident.
21 21 MR. CLAUSS: Right.
22 22 Okay. Some of the instrumentation that we had was 23 23 mild. We were very concerned to handle the behavior of the 24 24 sealing surfaces. And we wanted to know that it was -- what 25 25 sort of deformation would go on at the bulkhead. We had a
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I large number of capacity-type high resolution displacement 3c 2 transducers. These tranducers were capable of measuring 3 3 deformations on the order of a mill with good accuracy.
4 4 They also -- well, basically, in high temperature range that 5 5 we're looking at. Here is a photograph of some of the 6 6 displacement transducers. You can just see that as we moved 7 7 around the connectors, we had a number of these displacement 8 8 transducers. These two (inaudible) bulkhead annotation of 9 9 the door relative to the bulkhead.
10 19- ) We also had a lot of strain gages. The
\J 11 11 (inaudible) of the model was 123, with a high temperature 12 12 weldable gages: I have a photograph of that also. You can 13 13 see, again, a significant amount of instrumentation is on 14 the door.
1(~ ) So we were trying to measure the gages through wJ 15 15 the bends in the door.
16 16 In addition to that, we're also trying to measure 17 17 the temperature distribution in the lock. We had a total of 18 3 18 112 thermocouples that were located in the environment as N) 19 19 well as on the doors and the bulkhead and down the sweep 20 20 into the airlock. We measured leakage using specific 21 21 orifice plates which we named with differential pressure 1
22 22 transducers. Running it through some calibrations, we were 23 23 able to correlate the differential pressure with the heat 24 24 rate and there was switching circuitry to go from a small 25 25 orifice to a large orifice as the heat rate increased. Also p . - _ .
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1 six pressure transducers to measure the pressure in 2
(inaudible). The test chamber, pressurizing the inner door.
3 3 Also pressure in the chamber between the two doors in the 4
4 event that we got (inaudible) into that area. There are 5 5 pressure transducers in the (inaudible).
6 6 I'm going to start to skip to the analysis and 7 7 just gives you the results of the test programs, we are 8 8 running late. Let me just get the next couple of slides out 9 9 and skip right over those. I think I've talked about the 10 analysis enough.
10 - )
U 11 11 The first series of tests were done at ambient 12 12 temperatures, pressurizing the 1.15 times design. That was 13 13 basically just to convince ourselves that we could meet a 1('] 14 leak rate test specification without any seals.
15 15 We first tested without any seals installed, and 16 16 that's a test of 1B we conducted on the inner and the outer 17 17 door. We found that metal to metal contact by itself was i 18 3 18 not enough to preclude fairly significant leakage. This
(
19' '/ 19 corresponds to around 10 to 15 percent per day from 1 20 20 million cubic foot container.
21 21 Then the next two tests we did we had the eight 22 22 seals installed and again that was just to verify that the 23 23 seal, even though they are badly aged and deteriorated, were 24 24 capable of preventing leakage at near design pressures and 25 25 SIT pressures.
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Okay. In the major test was this high 3
2 pressure /high temperatura test. It was conducted basically 3 3 in three stages. The first stage at 100 degrees Fahrenheit.
4 4 The objective there was to look at the seal -- let me back 5 5 up just a little bit. One of the things we were trying to 6 6 do was use some of the data that we generated from our seal 7 7 test. And some of the basic conclusions that we had found 8 8 from the seal test was that the seals degraded at 9 9 temperatures in the average of 500 to 650 degrees Fahrenheit 10 depending upon the sealing material.
1r - )
11 11 Before it was degraded, leakage was mostly l
l12 12 dependent upon compression set retention. Okay. So for l13 13 this particular material, which is EPPM, degradation doesn't 1 14 become severe until about 650 degrees Fahrenheit. So we 15 15 wanted to do one stage of this test at what I would call 16 16 moderate remperatures which represents the stage in which 17 17 the seal isn't badly degraded and the compression set l
18 s 18 retention really dictates whether or not you get leakage.
i 19~' 19 So that was the first stage, and with the chamber heated at 20 20 l 400 degrees Fahrenheit, we pressurized in steps taking data 21 21 for each step, grade it, analogous --
22 22 We pressurized at 300 psig and we did not detect 23 23 any leakage. I think it was on a earlier slide, I didn't 24 24 say it, we were capable of finding leaks as small as .5 to 25 25 200 scfm range, which corresponds to only about 22 percent
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I mass today.
3 2 So there was no significant leakage, even at 3 400 degrees Fahrenheit and 300 psig.
3 4 Then the second stage was to heat this to 4 Okay.
5 5 very hot temperatures, 800 degrees Fahrenheit. Okay. We 6 6 depressurized the model first and then we heated it and let 7 7 it soak over night so it was sitting at 800 degrees 8 8 Fahrenheit for about eight hours.
9 9 Then the next morning, we began to pressurize flow to increments. And beginning at about 60, 70 psig, we noticed 1( -)
11 a very small leakage, like a .2 standard cubic foot per 11 12 12 minute. And that leakage slowly increased with pressure 13 13 until at 150, we had a heat rate of about two standard cubic 17w/) 14 feet per minute. Took the data at that pressure level and 15 15 prepared to take the next pressure step.
16 16 The leak rate -- as we started increasing 17 17 pressure, the heat rate suddenly grew very rapidly, well 18 -- 18 over 200 standard cubic feet per minute, which was really L) 19' ~' 19 the limit of our heat rate capability.
20 20 So effectively, the inner door was bypassed, and 21 21 at that point now, we're starting to pressurize the chamber 22 22 between the two doors. So that's the third stage.
23 23 Now, we're actualy putting the loading on the 24 24 outer door that corresponds to this (inaudible) where you've 25 25 got leak capacity (inaudible).
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1 As I say, the inner door is bypassed from the 3
, 2 pressure of two chambers. And I guess I'm not sure what 3 3 happened to that slide, but Chamber V-1 refers to the 4 chamber which pressurizes the inner door. And Chamber PL-1 4
5 5 refers to the chamber between the two doors.
6 6 At any rate, that pressure is essentially 7 7 equalized now in this stage of the test because you bypass 8 8 the inner door.
9 9 Then, at that point, then we presumed incrementing H3 The pressure of both Chambers was about 1 P~ s the pressure up.
L.)
11 11 300 psig, and no leakage was measured from the outer door at 12 12 all. And we did hold the 300 psig for some time.
13 13 Okay. Basic conclusions: The relative
)
14 displacement of tne sealing surfaces throughout this test, 1{G 15 15 even up to 300, was very small. And that was expected from 16 16 the analysis that that heat change may be calculated.
17 17 And even given the bad leak seal, there's enough 18 s 18 springback there that it can prevent a leak or small
- t id" 19 deformations. So that basically (inaudible) any leak in the 20 20 first stage of high pressure test.
21 21 In the second stage, when we got up to 800 degrees 22 22 Fahrenheit, this seal was badly degraded. And you already 23 23 have that lift there which prevented metal-to-metal contact.
24 24 At high enough pressure, the sealed material in that gap l I
25 25 between the metal surfaces was essentially injected. You V 1GN16 m ll E P O R TI N G SEliV10E a record of excellence
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know, the seal was so badly deteriorated that it just 3c 2 doesn't have the strength to just lift that type of 3 3 pressure.
4 4 MR. SIESS: Now, the moderate temperature in 5 5 water, that's the 400 F7 6 6 MR. CLAUSS: Right.
7 7 MR. SIESS: Okay.
8 8 MR. CLAUSS: Okay. And then another thing 9
9 that I haven't mentioned yet, but as we did observe when we H) i 10^) (inaudible) was that the sealed temperature got
.)
11 11 significantly less than the air temperatures. When the air 12 12 temperature of 800 degrees Fahrenheit, the seal on the inner 13 13 door, up until the point that we got leakage was only about 1()
(J 14 650, 660 degrees Fahrenheit. And there is significant 15 15 temperature gradient along the line for the airlock. This 16 16 is very similar to what was done in the EPAs and it's 17 17 something that shouldn't surprise anybody.
i 18 - 18 The outer door only had temperatures in the
\ /
19 19 neighborhood of three or 400 degrees Fahrenheit during this 20 20 test 2C.
! 21 21 So the reason we never got leakage from the inner 22 22 door, obviously, is that we never got temperatures l23 23 sufficient to break the seal.
l24 24 I guess that's essentially what I've been saying 25 25 here.
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I MR. SIESS: That last statement is an 2 The pressure is artifact of your test story, isn't it?
3 equalized.
3 4
4 MR. CLAUSS: I'm sorry?
5 5 MR. SIESS: You say that probably -- because 6 6 once the pressure is equalized, no further mixing took 7 7 place.
8 MR. CLAUSS: Yeah. If you have a lot of 8
9 9 interaction between the air at 800 degrees Fahrenheit and 10 air in the chamber, eventually that air would get up to 800 1{ ~ ';
11 M degrees Fahrenheit.
12 12 MR. SIESS: And even when a million cubic 13 13 feet inside, that would still be true?
14 MR. CLAUSS: Yeah, because there's 1/v"')
15 15 nothing --
16 16 MR. SIESS: No pressure to drive it?
17 17 MR. CLAUSS: No pressure to drive it.
I q -) 18 MR. MARK: In real life, though, that airlock
'x. ./
19 19 would have been insulated passing through a wall or 20 20 something.
21 21 MR. CLAUSS: Right. That's just going to 22 22 reinforce the conclusion that the outer door will not see 23 23 temperatures sufficient to degrade the seal.
24 24 MR. MARK: I was thinking the temperature 25 25 difference end to end would be a different number. Might o - _ _ - .
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2 MR. WARD: It would test -- you get heat loss 3 3 out the cylinder between the doors.
4 How much of the airlock is 4 MR. SIESS:
5 5 outside the containment?
6 6 MR. CLAUSS: In actual containments?
7 7 MR. SIESS: Yes.
8 8 MR. CLAUSS: It would depend on the type of 9 9 containments there. If it's in the steel containment --
1 10 well, typically, the airlock is routed into the inside of 11 11 the containment near the inner door. So everything beyond 12 12 the inner door is outside containment or in the containment 13 13 wall. And a steel containment, obviously, the thickness of 1 14 the containment wall is small, so most of it is outside the 15 15 containment. The reinforced concrete wall is four foot 16 16 thick, so it's only going to be about five or ten feet of 17 17 the airlock that's located outside the wall.
18- s 18 MR. SIESS: This says that there's really 19 19 nothing that happens in a LOCA that would cause extensive i 20 20 leakage through this kind of a lock. Right?
21 21 MR. CLAUSS: Yeah.
22 22 MR. SIESS: And yet when I see leak rate 23 23 tests, very frequently, they can't pass the heat rate test 24 24 because the heat gets through the first airlock. And you go 25 25 back and you find that somebody banged into a seal the last m _.- -
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I time they hauled something through it.
2 Now, would that be this kind of seal or one of the 3 other types?
3 4
4 MR. CLAUSS: No, it could be this type of a 5 seal. But there's a big difference in what we consider a 5
6 significant leakge from a severe accident. You have a small 6
7 7 level that are allowable in an IRT.
8 8 MR. SIESS: I know. But --
9 9 MR. CLAUSS: But mainly our redegrading 10 10 g system wasn't capable of measuring leaks that --
V 11 Il MR. SIESS: No. But what I'm saying is, that 12 12 although -- when the airlock gets in decent shape before the 13 13 LOCA wil' survive, that's what these tests tell me. It 1 14 won't fail es a result of the LOCA.
15 15 MR. CLAUSS: Right.
16 16 MR. SIESS: But if they do fail, it will be 17 17 because they weren't tight to begin with.
18 18 I mean, an airlock that won't withstand the 19 O 19 60 psig test without excessive leakage, do you think it's 20 20 going to get better in that 300 psi?
21 21 MR. CLAUSS: Yeah, as a matter of fact I do 22 22 because -- okay. A 60 psig, you haven't necessarily fully 23 23 compressed that seal. And you --
24 24 MR. SIESS: Suppose the seal isn't there for 25 25 six inches. That's the kind of cases I'm talking about.
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I MR. CLAUSS: The seal isn't there?
S i 2 MR. SIESS: In cases where they try to run 3 3 their heat rate test and they can't get any pressure in it.
4 4 They go around and check, and here's a chunk out of the seal 5 5 on the airlock, either somebody carried something --
6 6 MR. EBERSOLE: When he says a chunk, he means 7 7 a chunk --
8 8 MR. CLAUSS: Yeah, it's not going to get any 9 9 better if that's the case.
Ir- 10 MR. SIESS: Okay. That tells us if we want G
11 11 to control that source of leakage, which is potentially a 12 12 big one -- and I think if you look back at LERs in the heat 13 13 rate test, you will find it's a frequent source. It's got 1q'~ 14 to be done by inspection maintenance and procedures.
R.J 15 15 MR. EBERSOLE: Can't you put a pressure 16 16 inside between the doors and sort of verify the condition?
17 17 MR. SIESS: Sometimes they do this testing j 18-~ 18 beforehand. You know, this might not be an integrated leak il 19"' 19 rate test within the --
20 20 MR. EBERSOLE: Sure, just a pretest.
21 21 MR. SIESS: It's (inaudible) reservations.
22 22 And you frequently see it happen. This gives me comfort.
l23 23 And if it's in good shape before, you know --
24 24 MR. EBERSOLE: It looks like a nice function l25 25 of the outer door is simply insulation, thermal insulation.
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1 MR. SIESS: Well, the NRC had some criterion B 2 that you had to test the airlock seals every time you went 3 3 through it. And this was rather difficult to do because it 4 always left somebody inside. You know, you had to do it by 4
5 5 pressurizing between the two doors, which meant to put a 6 6 strong back on the inner door and then somebody had to get 7 7 out. And so they did let them test it by pressurizing 8 8 between the seals.
9 9 MR. CLAUSS: That's right.
10 10m MR. SIESS: But this has been a continuing 11 11 problem, but it's administrative procedure-type thing. And 12 12 I think they recognize that.
13 13 And what about your last line up there?
1(
14 MR. CLAUSS: Well, okay. This is a very 15 15 recently completed test. I don't have the report ordered to 16 16 do that. I don't have all of the data at this point. So 17 17 that's one of the things that needs to be done yet, is to 18 18 thoroughly look through all the data and get it reduced to 19 0 19 the appropriate units and so forth to get in the report.
20 20 But once I have that report -- incidentally, I 21 21 should have said a long time ago, this work was contracted 22 22 out of the (inaudible) in (inaudible).
23 23 But once I have that report, then Sandia will 24 24 start picking this up again and we'll be doing some 25 25 post-test comparisons with the analysis. And I skipped over O manumm
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I the analysis, but I'm pretty sure that I have showed you 2 that analysis.
3 3 MR. SIESS: But your analysis showed that 4
4 there was very little separation due to pressure.
5 5 MR. CLAUSS: That's right. And that seems --
6 6 MR. SIESS: And so if the seals were even 7 7 (inaudible) in there, they'll seal it?
8 8 MR. CLAUSS: Yeah, that's what the analysis 9 9 said. And the part --
1 10 MR. SIESS: That's a function of the physical 11 11 design of the door. It was that stiff.
12 12 MR. CLAUSS: That's right. It's going to be 13 13 dependent on stiffeners.
14 MR. EBERSOLE: Chot, let me ask you: Is the 1('")
15 15 test performed with both doors closed? I thought the 16 16 original purpose of the doors -- the two doors was to cover 17 17 for that small fraction of total time that a door would be 18 s 18 opened when you had (inaudible).
( )
19 "' 19 MR. SIESS: That's right.
20 20 MR. EBERSOLE: But -- and I also thought that 21 21 was really silly because that's such a small fraction of 22 22 time. But then I find the real value currently is in the 23 23 thermal protection you get from the outer door.
24 24 MR. BENDER: Two kinds of arguments. One is 25 25 the argument that has to do with the fact that the
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219 1 likelihood -- there are two premises involved. One is the 3
2 likelihood that the severe accident will occur. And when 3 3 that occurs, there is no reason to argue that simultaneously 4 4 both doors will be open.
5 5 The other is the deal with the other kinds of 6 6 LOCAs which may occur that may not lead to a severe accident 7 7 where you want to have just the integrity of the 8 8 containment.
9 9 MR. SIESS: Dave, the analysis predicted the 1 10 very small openings. You haven't looked at the test data 11 11 yet, have you?
12 12 MR. CLAUSS: I haven't been able to look at 13 13 it in any detail, but I do know the gaps were small, on the 1 14 same order of magnitude, at least. That was what we 15 15 predicted in the analysis. Whether they track it with 16 16 pressure very accurately, I don't know yet.
17 17 MR. SIESS: That's probably the main thing 18 g 18 you're going to be looking at, isn't it?
\
19'J 19 MR. CLAUSS: Yes.
20 20 MR. SIESS: Now, was the seal material 21 21 typical? I know it's typical to some -- how many different 22 22 seal materials do they use on these doors?
23 23 MR. CLAUSS: I believe that most of the 24 24 airlocks have the same sealing material. But there are 25 25 differences in the cross-sections, the seals that are used.
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They're not (inaudible). I think there are some with 2 2 gumdrop seals. ,
3 3 MR. HORSCHEL: I guess when they first 4
4 started making the double dogear seal, it was generally out 5 5 of silicone rubber. But through time, they've changed them 6 6 to the EPDM. I think almost all of them, through normal 7 7 replacement of them, are now using the EPDM on the double 8 8 dogear configuration. ;
9 9 MR. CLAUSS: At one point, there were some 10 10 with silicone in them. But I'm fairly confident that there 11 11 aren't --
12 12 MR. SIESS: Is the seal attached to the door 13 13 or the frame?
1( 14 MR. CLAUSS: Pardon me?
15 15 MR. SIESS: Is the seal attached to the door 16 16 or to the frame?
17 17 MR. CLAUSS: The seal is in a group that's in
. 18. 18 the door.
19 19 MR. SIESS: In the door.
20 20 MR. CLAUSS: Uh-huh.
21 21 MR. SIESS: Any other questions?
22 22 MR. CLAUSS: Let me just say one other thing 23 23 as far as analysis.
24 24 We did predict a small deformation. and given 25 25 those small deformations, I think we would never expect O _ _ __._ ___
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leakage out of the moderate temperatures. But there 3 2 wasn't -- you know, we produced leakage here, and even that 3 3 might be something you would never see in natural 4
4 containment because by aging those seals so badly actually 5 5 excluded this lift, if you will, into the gap between the 6 6 door and the bulkhead.
7 7 Now, the double dogear seal is actually designed 8 8 to fully compress within the groove. And if you didn't have 9 9 this lift, and as you pressurized, before you compressed the 1 10 seal into that group, then you would have good memorable 11 11 contact. And even at very high temperatures, it's possible 12 12 that you might not get leakage if that was allowed to 13 13 happen.
1 14 MR. SIESS: What's planned for the future, 15 15 any other types?
16 16 MR. CLAUSS: Well --
17 17 MR. SIESS: If the analysis works out, you're 18 going on with the analysis?
!. 18( .
'lY') 19 MR. CLAUSS: That's right. And we will try 20 20 it with analysis at other designs of a significant 21 21 difference.
' 22 22 MR. COSTELLO: There is a population that 23 23 came up a couple of years ago.
2 24 24 MR. SIESS: How good do you think the 25 25 analysis has to predict that gap to be able to use it to O maww1ss i
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. MR. CLAUSS: It depends --
3 MR. SIESS: You said an order of magnitude 3
4 4 before, and I know you didn't mean that.
5 5 MR. CLAUSS: Pardon me?
6 6 MR. SIESS: You said an order of magnitude 7 7 before, and I know you didn't mean that. That's a factor of 8 10.
8 9 MR. CLAUSS: Yeah.
9 10 10']
(>
It really depends on how large deformations are.
11 11 But deformations are less than 10 mils, was what the 12 12 analysis predicted here. The difference between one mil and 13 13 four mil or five mil isn't all that significant. But when 1(s 14 you start getting up to deformations on the order of the V
15 15 springback in the seal, obviously, it becomes very critical 16 16 and you have to have very good accuracy.
17 17 Now, that only addresses (cough).
18 s 18 In the high temperature scenario, any small k
19'_) 19 deformation will probably leave leakage. You don't have 20 20 good metal-to-metal contact.
21 21 MR. SIESS: Well, now, you've made that 22 22 analysis, and let's say that analysis predicts that the 23 23 opening to be two mils at 300 psi. And when you get to
- 24 24 looking at the test results, you find that it was 10 mils at 25 25 300 psi. Is that analysis good enough to use to look at KlDlQNlDlY REPORTING SERVlOE a kconi ofiAccilence
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I other airlocks?
8 2 2 MR. CLAUSS: No, it's not. We would have to 3
3 go back and try to explain the difference.
4 4 MR. SIESS: You've got some idea of what's 5 5 good enough?
6 6 MR. CLAUSS: Well, I would like to see at 10, 7 7 20, 20 percent or so.
8 8 MR. SIESS: Okay. Thank you.
9 9 MR. EBERSOLE: What percent of the seals are 10 1(3 compressed? That's a fixed percentage compression, isn't LJ 11 11 it?.
12 12 MR. CLAUSS: No -- well, under what 13 13 conditions?
- 1() 14 MR. EBERSOLE: Under when you close the door.
L.)
15 15 You compress the COA fixed percentage of its normal 16 16 dimension.
17 17 MR. CLAUSS: No, that's really not true
!18t \ i 18 because the -- the seal is employed to cross into that 19~ 19 groove just by closing the door. There's a latch --
1 20 20 MR. EBERSOLE: Well, isn't there a metal stop
, 21 21 that says, "I want 25 percent compression," or comething?
l 22 22 MR. CLAUSS: There are limits as far as what
! 23 23 you can get. But when the door is simply closed, there's a 24 24 latch that's compressant sealed. But it doesn't compress it l25 25 because you get metal-to-metal contact.
1 i
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MR. EBERSOLE: So you can oversweep it, or 3
2 can you. Not overload it the next time you won't 3 3 (inaudible) that tightly. What's the uniformity of 4
4 compression; just a variable?
5 5 MR. CLAUSS: Well, we measured that during --
6 6 as part of this exercise. We started out with the seal 7 7 before aging, closed it with the latch and measured the 8 8 compression of various points along this privileged seal, 9 9 and it varied. It varied anywhere froin, I think, a tenth of 10 an inch to about an eighth of an inch. That's not a big l 1p-]
11' 11 difference, but it does vary.
12 12 MR. SIESS: I think you said, though, that 13 13 there was no seal. You got metal-to-metal contact. So
,le"N 14 there is no mechanical stop. Am I right?
\
l 15' 15 MR. CLAUSS: Thet's right.
16 16 MR. EBERSOLE: Well, there's no 17 17 reproducability of closure. I thought a good seal had to 18 x 18 come to a positive stop with a known percentage of
()
19' 19 compression.
20 20 MR. CLAUSS: That's not the way it works. I 21 21 think I would tend to agree with you, you should always have l 22 22 the same compression. But that's not the way it works.
23 23 MR. EBERSOLE: The operators, you know -- I 24 24 don't know. Maybe a muscular man will do more than that --
25 25 MR. CLAUSS: Well, you know, the latch is --
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MR. EBERSOLE: It looks electric.
3 2 MR. CLAUSS: Well, it's a roller with a 3 3 (inaudible). It's not la e the operator is going to buy 4 She needs to slide this --
4 this one off the floor.
5 5 MR. EBERSOLE: Okay.
6 6 MR. CLAUSS: So you should get uniformed 7 7 core.
8 8 MR. CLAUSS: Fine, okay.
9 9 MR. EBERSOLE: But if you closed that latch 1 10 without a seal in there, you said you would get metal to 11 11 metal.
12 12 MR. CLAUSS: Well, the -- you will with 13 13 pressure because the pressure is pressuring the door.
1 14 MR. EBERSOLE: After you took the pressure --
15 15 MR. COSTELLO: Right.
16 16 MR. EBERSOLE: Okay. Thank you.
17 17 MR. COSTELLO: Okay. The next presentation
- 18. 18 speaks more to work that's ongoing and projected for next
(
19, 19 year. It turns out together, we're going to -- one of the 20 20 thinge we're going to have to defer until next year because 21 21 of budget is work on inflatable seals, those other types of 22 22 airlock seals.
23 23 And we're going to this year concentrate on 24 24 scoping activities about, is there a potential failure modes 25 25 for bellows.
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Fred Parks has been working on this and will speak 3
'. 2 about it. Dr. Parks is -- you'll learn when I say here, I 3 3 guess you haven't seen him before.
4 4 5 5 Seals And Gaskets, Inflatable Seals, and Bellows 6 6 7 7 MR. PARKS: As Jim mentioned, my name is Brad 8 8 Parks. There are three topics that I'll be talking about 9 9 briefly, all concerning the containment penetration work.
1 10 The first is the seals and gaskets sturly. This study is 11 11 pretty well completed at this time, but the testing has been 12 12 done and a final report has been written.
13 13 The second topic says inflatable seals. We've 14 1 14 done pretty much all of the preliminary planning and U
15 15 fabrication of test fixtures for the inflatable seals.
16 10 There are things pretty well set to start testing and exact 17 17 timing of when we do the test will depend on our future l
' 18 s 18 planning. i i
( i i 19 19 And the final topic is that of bellows. Bellows, 20 20 we are just getting started looking at the problem of seeing i 21 21 if there is a probablem with bellows.
1 l22 22 MR. EBERSOLE: Is this big structural bellows i23 23 like they have in the boilers on the downcomers or.
l24 24 MR. PARKS: Yes, for the Mark-I.
25 25 MR. EBERSOLE: Yeah.
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MR. PARKS: That type of bellows, yes.
2
& MR. EBERSOLE: All of those.
3 3 MR. PARKS: Right.
4 4 First, I would like to discuss a little bit about 5 5 the seals and gasket tests. These tests were performed at 6 6 two different locations, one being Sandia National 7 7 Laboratory and the other one Idaho National Engineering 8 8 Laboratory. And it just shows here, 22 tests were done at 9 9 each location for a total of 44 different field and gasket 1 10 tests. That means that all the testing has been completed.
11 11 The final report from the Idaho tests were published in July 12 12 of '87, and the final report for the Sandia test, which also 13 13 includes a summry of the Idaho test has been completed and 1 14 is currently under final review process.
15 15 Just to give you an idea of what types of things 16 16 were investigated in the seals and gasket test, I listed the 17 17 various test parameters that were looked at during the 18 3 18 testing. The reason for selecting these particular type of
( i 19 19 materials and also these type of seals is that a study was 20 20 done at Argon National Labs in which they surveyed many 21 21 different types of containments and they found these 22 22 materials to be the inost prevalent, and in a vast variety of 23 23 different contairments.
24 24 The three materials that were tested, the first 25 25 one is the EPDM material, silicone rubber and the neoprene.
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I Four different types of seals were tested; the 2 double 0-rings, the double gum drop, the double dog ear and 3 3 the double tongue-and-groove.
4 They also looked at three different types of aging 4
5 5 on these seals. The first type of aging, if you want to 6 6 call it that is this testing of the seals in the unaged 7 7 condition; in other words, no artificial aging was applied 8 8 to these materials.
9 9 The second group of aging on the materials was l{ ) 10 this thermal aging only, where they aged it at 300 degrees 1 11 Fahrenheit for a week.
12 12 And then the final category of aging was thermal 13 13 and radiation aging, where they aged it at 300 degrees 1 14 Fahrenheit for a week and then 200 after that at (inaudible) 15 15 per hour. Here again, we're just trying to simulate a 16 16 40-year life in the seals.
17 17 Two different types of environments were used 18 s 18 during the seals and gasket test. First being steam. They I
19' 19 also used -- some of the tests, they used heated, dry air.
20 20 The final topic parameter is the amount of squeeze 21 21 in the seal itself during the test. This is a measure of 22 22 how much the seal is compressed on the side of the test 23 23 feature. The actual quantitative measure is the percentage 24 24 of the original thickness of the seals that is compressed 25 25 during the test. And it varied from 9 percent of the V RENN N REPoliTlNG SERVlCE a reconi of excellence i
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I original thickness to as much as what was necessary to get 3
t 2
metal to metal contact. For metal to metal contact, it was 3 about 25 percent.
3 4
4 MR. EBERSOLE: And the 9 percent, was that 5 5 just established by dimension or by the mechanical load 6 imposed -- you know, the type of pressure.
6 7 7 MR. PARKS: They have a test fixture 8 8 (inaudible) so that they'll have a fixed gap in the test 9 9 fixture and then write down the key plants.
10 MR. EBERSOLE: In actual practice, do they lQ '
x, i
11 close seals that way or do they close them to some sort of 11 12 12 static load level by adjustment of the cams?
13 13 MR. PARKS: That's one question I can't 14 14 answer.
15 15 MR. EBERSOLE: Okay.
16 16 MR. PARKS: Okay. I'm going to hit the 17 17 highlights of the test results.
18 s 18 All the tested seals failed at more severe
( )
19 19 pressure and temperature conditions than were predicted for 20 20 the severe accidents of PWR and MK-III type containments.
21 2: Some of the tested seals failed at lower 22 22 temperatures than predicted for the Mark-I and Mark-II 23 23 containments.
24 24 Most of the failures occured at a temperature 25 25 range of areound 500 to 650 degrees, which is haflway a _ - -__ --
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I between the predicted severe accident scenarios for the PWR 3
2 Mark-III and that of the Mark-I and Mark-II, 3 From the results of these tests they couldn't find 3
4 4 significant effect that aging had on the failure of 5 5 temperatures of the seals. And finally, some of the Idaho 6 6 tests were made in which one of mating (inaudible) services, 7 7 at a angle to simulate flange rotation that might actually 8
8 occur on -- due to rotation of the sleeve. This rotation 9
9 varied from zero to 12 degrees. And the results of these 10 lp ,) tests show that the flange rotations didn't have much affect 11 11 on the failure of temperature on the seals, but it did 12 12 affect the amount of seepage before failure.
13 13 MR. MARK: You say they all failed under some 1 14 conditions. Was it apparent that one of the materials was 15 15 favorable compared to the others or one of the seal types 16 16 was favorable, or did they all fail at exactly the same 17 17 temperature?
18 s 18 MR. PARKS: No. As a general rule, the EPDM i )
19' 19 materials tested around 600 to 650 degrees.
20 20 MR. MARK: But you had three materials.
21 21 MR. PARKS: Yes, sir. (inaudible) materials 22 22 around.
23 23 MR. MARK: Was one better than the others?
24 24 MR. PARKS: The failure temperature on the 25 25 silicone was normally less than that of the EPDM. Again,
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that depends on the environment. And the steam environment 3
t 2
of the silicone is affected detrimentally, quite a bit. And 3 3 the steam environment for the silicono seal has normally 4
4 been around 500 degrees Fahrenheit. If you tested the same 5 5 silicone seal in air, it would probably fail around 650 6 6 degrees Fahrenheit.
7 7 As a general ranking, EPDM was better than 8 8 silicone and neoprene I think was down there around the same 9 9 sort of behavior.
10 1(~; MR. MARK: Neoprene is the least favored.
R_)
11 11 MR. PARKS: I would think so, yes.
12 12 MR. MARK: And now, the dog ears and the 13 13 other things, is one of them better than the other?
1 14 MR. PARKS: I don't remember seeing any trend 15 15 saying that one was definitely better than the other.
16 16 MR. SIESS: Where are these used? Where are 17 17 these seals used in a nuclear power plant?
18 3 18 MR. PARKS: This testing was a generic type t !
19' 19 testing, just testing the sealed materials.
20 20 MR. SIESS: I know.
21 21 MR. PARKS: As specifically used as the 22 22 penetration or the --
23 23 MR. CLAUSS: To be used, like the 24 24 tongue-and-groove and gum drop are designed to test and see 25 25 if the dry wall (inaudible). You see gum drop, 0-ring, I
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I think I even see some tongue-and-groove.
S. 2 MR. SIESS: And hatch closures or mechanical 3 3 penetrations.
4 4 MR. CLAUSS: This is for operable 5 5 penetrations, I believe.
6 6 MR. SIESS: Operable penetration.
7 7 MR. CLAUSS: Includes hatches and air locks.
8 MR. SIESS: So there would be no problem of 8
9 replacing a particular pipe if it turned out to be pretty 9
1 to bad.
11 11 MR. CLAUSS: In fact, that's already been 12 12 done. There has already been several utilities that 13 13 replaced silicone seals with EPDM.
14 MR. EBERSOLE: Are these used in the 1R
)
15 15 atmospheric relief and ventilation valves and monsters, you 16 16 know, that are supposed to close but were found not to be 17 17 able to if there was a LOCA there?
18 18 MR. HORSCHEL: The (inaudible) I'm not sure.
19 19 Part of the electrical penetration, you see a lot more 20 20 sealing compound or the (inaudible) is used. They have 21 21 epoxy, they have flaps and electrical penetrations. I guess 22 22 I'm really not that familiar with that phase.
23 23 MR. EBERSOLE: Well, you remember the big 24 24 flack when we found out that these valves were running open 25 25 all the time, yet they had no forcing functions obtained O - _
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I closure if there was a preexisting LOCA because of the 3
2 2 dynamic loads that would be obtained in that trenching and 3 3 that's been fixed by partly closing the big ones and putting 4 But they have to have some kind 4 more muscle on the others.
5 5 of seal -- I think these are butterflies, that will go 6 6 through a real awkward sealing function.
7 7 MR. PARKS: I'm not familiar.
8 8 MR. HORSCHEL: As far as valves are 9 9 concerned, the NRC does have a program looking at that. I 10 believe that's --
1(]
11 11 MR. COSTELLO: Yeah, I was going to say that 12 12 now I'm trying to recall the result of some tests we had 13 13 done primarily by Idaho Na tional Laboratory. We've had a lq 14 series of tests that all the LOCA temperatures have been v '.}-
15 15 extended, as have accident temperatures. If you're 16 16 interested, I could --
17 17 MR. EBERSOLE: No. I'm talking about the 18 18 actual physical process of closing in the presence of 19 19 violent winds which might even blow the seal out.
20 20 MR. SIESS: That's not a seal problem.
21 21 MR. EBERSOLE: Well, it might even blow the 22 22 seal off, as far as I know.
23 23 MR. SIESS: This says seals and gaskets.
24 24 Does this cover the gaskets that are used in mechanical 25 25 penetrations? Are these kind of things we're talking about
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l here used to close mechanical penetrations?
2 4 MR. HORSCHEL: What is your definition of 3 3 "mechanical penetration"7 Personnel airlocks, putting the 4
4 hatches down?
5 5 MR. EBERSOLE: Only those things, only the 6 6 movable openable things.
7 7 MR. HORSCHEL: What if there isn't 8 8 (inaudible), though?
9 9 MR, SIESS: You've asked a question they 10 1{,)'~
can't answer, but they'll look it up when we -- Jim will 11 11 find out what the --
12 12 MR. COSTELLO: We'll have some testo on it --
l 13 13 I should have brought a copy of the --
1 14 MR, SIESS: I don't think those tests are on 15 15 butterfly valves, though, which is what Jesse's talking 16 16 about, three foot butterfly.
17 17 MR. COSTELLO: Yeah, three foot butterflies.
I18 s 18 MR. SIESS: Are these the kind of seala that
)
l 19 ' 19 you use on the equipment hatch that you have in your model 20 20 of the airlock and dry water closures?
21 21 MR. COSTELLO: The emphasis on the --
l 22 22 MR, SIESS: Dry wall heads, you said.
23 23 MR. COSTELLO: The emphasis on the operable 24 24 penetrations changed several years ago, if you'll recall,
( 25 25 and many arguments were made that began to point out, as you q _ __
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- 3. 2 indeed operable penetrations were the most (inaudible) leak 3 3 sources.
4 4 MR. SIESS: Okay. Very good.
5 5 MR. PARKS: Okay.
6 6 The second topic that I talk about is this 7 7 inflatable seals. I suppose you could think of it as a 8 8 special case of one of the steals that we've already talked 9 9 about. To our knowledge, there's not any test data out 1p 1 10 there for inflatable seals, at least not in the bulk of the
' s 11 11 (inaudible).
12 12 There are normally used to prevent leakage around 13 13 the personnel and the escape lock doors. They are currently 14 14 installed, or at least planned for 13 different commercial 15 15 nuclear power plants. All the installations are in either 16 16 PWR or Mark III type containmentc.
17 17 MR. EBERSOLE: Can I ask a question?
! 18 - 18 MR. PARKS: Sure.
l \)
, 19 ~ 19 MR. EBERSOLE: These are part of a common 20 20 general problem in that they are tied to a nonsafety grade 21 21 air system unless there just models, which only have the 22 22 capacity to fail in air pressure but can deliver 23 23 contaminants, water, rust, junk and all sorts of things --
24 24 MR. PARKS: Inside.
l25 25 MR. EBERSOLE: -- inside the steel. And 1
~
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1 that's the common most failure that gets everything inside 3
2 these air systems and it's under consideration, not 3 3 physically, but for all the controllers, as being of serious 4
4 deficiency in general design practico.
5 5 Did you look at the aspect of failure by the mode 6 e of delivering the wrong kind of air, or not enough air, or 7 7 moderate air pressure, try not to seal, our whatever? In 8 8 other words, did you look at the effects of failures in the 9 9 air supply in both the positive and negative direction?
lg -) 10 MR. PARKS: We have not started these steps V
11 11 yet.
12 12 MR. EBERSOLE: Okay.
13 13 MR. SIESS: That's not within your scope --
14 14 MR. PARKS: That is the --
15 15 MR. SIESS: -- to measure mechanical behavior 16 16 of the seal itself?
17 17 MR. PARKS: That is within the scope and 18 s is that's the primary objective of just looking into the
( )
19 ' 19 canceled behavior of the seal and how it behaves for 20 20 different internal air pressures.
21 21 MR. EBERSOLE: And air qualities.
22 22 MR. PARKS: Air quality, we haven't planned 23 23 to look into, but maybe that is something we should look 24 24 into.
25 25 MR. SIESS: Okay.
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I MR. EBERSOLE: Well, there is just still one S
- i. 2 air system up with 200 gallons of water.
3 3 MR. SIESS: Can you relate those 14 plants to 4
4 either vendors or IME's?
5 5 MR. PARKS: I can relate them -- I can tell 6 6 you what plan it is.
7 7 MR. SIESS: Yeah, but I'm wondering why only 8 8 14 out of 120 plants have chosen this particular system.
9 9 It's all the Mark-III's.
I P~'y 10 MR. PARKS: Mark-IIIs and PWRs.
\_)
11 11 MR. SIESS: It's only two pairs of PWRs and 12 12 the two ice -- two of the ice condensors.
13 13 MR. PARKS: Right offhand, I can't tell you 1 14 why --
15 15 MR. SIESS: This is an A/E responsibility and 16 16 not a vendor responsibility, isn't it?
17 17 MR. COSTELLO: Yeah.
18 s 18 MR. WARD: But they are not all the same A/Es
()
19'~' 19 because you've got Duke and TBA in there.
20 20 MR. SIESS: I know it. South Texas, that's 21 21 an interesting decision.
22 22 MR. EBERSOLE: Are you going to look at this 23 23 in the context of this system interactive effects from the 24 24 air system?
25 25 MR. PARKS: Yes, I'll discuss this next one, U
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I we've been on this one too long.
3
& 2 SOMEONE: This next framework is --
3 3 MR. PARKS: Just for your general information 4 4 to let you know where these seals are located and what 5 5 plants they're located in.
6 6 There is a total of 26 different locks out there 7 7 so that it be personnel or escape locks, or they use 8 8 inflatable --
9 9 MR. SIESS: Where they have used inflatable 10 1{-}
seals, they have used them for all the locks?
11 11 MR. PARKS: As far as I know. I don't know 12 12 that -- I can't make that conclusion.
13 13 Let's look at a typical application of inflatable 1 14 seals and a personnel airlock. Here are your two doors, 15 15 here and here, for the personnel airlock. There is normally 16 to two different -- or two seals side by side; would be one 17 17 here and one here, anything one the innerdoor lock.
18 s 18 A typical size for these airlock doors is about I
)
1@' 19 six and a half feet high by about three and a half feet l
20 20 wide. If you take those dimensions and calculate the total 21 21 parameter around the door, it's about 240 inches. So we 22 22 have a potentially large leak area around the door there.
23 23 There is a door stop along the two vertical edges 24 24 of the door, on this edge here. You can see it better in 25 25 the lower figure. It's about four and a half feet long on l
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1 each side. Here we can see the inflatable seals a bit 3
. 2 better. We have leakage pass both inflatable seals, this 3 3 one and this one (indicating), I suppose this door stop 4 4 would inhibit some leakage from going past the second seal.
5 5 MR. EBERSOLE: Can I ask you a question. I 6 6 have a strong suspicion those ought to all be outlawed, and 7 7 I'll tell you why. I'm going to guess that you're going to 8 8 find it's been postulated that the air supply, because of 9 9 the disruption in the systems, would have been lost when you 10 1p-) have an emergency, like a typical case is. So you will find V
11 11 a standby bottle on the side with a new check valve. It 12 12 says, "Oh, now, go back on the bottle," but while you were 13 13 normally running, those th ngs are sustained even large 1 14 (inaudible) by the capacity of the normal air system that 15 15 will not sustain (inaudible) on a bottle. It will just go 16 16 right away. And yet there is no monitoring of the 17 17 reliability of the checks.
18 s 18 MR. SIESS: Jesse, if we could get them
( )
19 10 outlawed, we would save the money on this research.
20 20 MR. EBERSOLE: Might be the cheapest thing.
21 21 (Laughter) 22 22 Maybe we could get rid of PWRs, Chet.
23 23 MR. PARKS: Okay, The next point I want to 24 24 make is what happens if we lose pressure inside of the seal?
25 25 MR. SIESS: How much pressure is there inside i
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l the seal?
2 MR. PARKS: Typically, in a PWR, it's around 3 3 60 psi. That's the information that I get, yes.
5 5 MR. PARKS: I said 60 psi. It's 90 psi 6 6 inside the seal for the PWR.
7 7 For the BWR, I don't have that information right 8 8 now.
9 9 MR. SIESS: So pressure inside of the seal is 1p w 10 a great deal less than the outside pressure?
()
11_ 11 MR. PARKS: The severe accident pressure, 12 12 yes.
13 13 MR. SIESS: And probably, the seal was 1 14 designed for LOCA.
- 15 15 MR. PARKS
- Thet I can only speculate; I 16 16 would think so, yes.
17 17 MR. EBERSOLE: Well, then they are going to 18 - - 18 surely leak, i
19'~' 19 MR. SIESS: 140 on the other side of that 20 20 seal.
21 21 MR. PARKS: Real quickly, a couple of other 22 22 details. I'm still looking at this same door, this part of 23 23 the detailed infraction and the section at the top of the 24 24 door. There is nothing back here to prevent any leakage l25 25 past the second seal.
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So if we -- in the best case, we think this 240 3 2 inch parameter around the door, and say that the door stops 3 3 are going to stop (inaudible), about 100 inches roughly, 4
4 we've still got roughly 140 inches of the parameter that 5 6 looks like this. If we lose pressure in the seal, we may 6 6 have as much as three-eighths of an inch of gap between the 7 7 seal and the door frame all the way around perimeter of the 8 8 door.
9 9 MR. SIESS: That's a big leak.
10 1p S MR. PARKS: That's my point. If we multiply 11 1 this three-eighths times the uninhibited perimeter, we'll 12 12 get about 50 square inch leak area. That's if we lose, 13 13 totally lose air pressure in the seal. I 1 14 MR. SIESS: Do the two seals have a separate 15 15 air supply?
16 16 MR. PARKS: That's another question I haven't 17 17 been able to give an answer to. I have asked that question, 18 , 18 but I . . .
()
19'" 19 MR. EBER60LE: Well, even if they do, they've 20 20 got a check valve in the system that may leak, that 21 21 separates them.
22 22 MR. PARKS: Again, for your information, to 23 23 give you a feel for what these seals look like. You've 24 24 normally got five and a half -- five and three-cighths
'25 25 inches wide, about one inch here, about an inch an a
,q --- . . - -
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241-I quarter. The actual inflatab3e bars -- there are two bars 8
g 2 in the field -- about three and a half inches by about an 3 3 inch. All the seals that I know of anyway are made of EPDM 4
4 material.
5 5 As I mentioned earlier, most of the protest were 6
6 kept. We have had a -- or actually two test fixtures 7 7 fabricated to test the inflatable seals in. The figure that 8 8 is shown here is the actual overall test chamber and this 9
9 thing here is the actual test picture in place inside the 10 10 ~'s test chamber. The shape of the test ficture is that of a N..)
11 11 short length of cylinder; it's about 36 inches on the outer 12 12 diameter, and it's about 13 inches long this way.
13 13 The way this particular fixture works is pressure 1 14 enters the fixture through 32, five-eighth inch diameter 15 15 holes that are equally spaced around the bottom of the 16 16 fixture. Pressure enters here (indicating). Once we get 17 17 leakage past the first seal, we can measure that for leakage 18 18 ports in here that are located between the two seals, at 19 19 the --
20 20 MR. SIESS: Why don't you use the next slide?
21 21 I think it's a lot easier to see.
22 22 MR. PARKS: Okay. There is just a section 23 23 through the actual, through the test fixture. Again, this 24 24 is where the pressure enters the test fixture. We could 25 25 measure leakage between the soais here, and if we get a leak I
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I past the safety seal, we can measure it and measure these 2
supports around the perimeter in the upper end there.
3 3 MR. BENDER: What is it we're going to do 4
4 with this data when we get it?
5 5 MR. SIESS: We're going to find his own work 6 6 is (inaudible), Jesse says.
7 7 MR. BENDER: I asked a serious question.
8 S What are we going to do with it?
9 9 MR. PARKS: The main thing that we want to 10 1C look at, and again I'll got to that in couple of slides, is C/
11 ll to see how much pressure we need inside the seals so that l l
12 12 they don't leak for a given amount of external pressure out
{
13 13 here. See if we've got 90 psi in the seal, how high could 14 14 this external pressure be before we get leakage? Okay?
15 15 That's the main number that we're looking at.
16 10 If it's possible, in the event of a severe 17 17 accident -- and again I say, if it's possible, it might be 18 3 18 that we're being -- this is being very optimistic, I think.
! i 19 ' 19 If we could increase the seal pressure and the seals to make 20 20 it 150 psi, we might could withstand or withstand the 21 21 pressure -- this pressure boundary in the event of a severo 22 22 accident. Whereas, to leave it at 90 psi and the external 23 23 pressure during the severe accident reaches 120, wo 24 24 might --
25 25 MR. EBERSOLE: Who set that as an objective, l
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l did you all or did NRC7 My objective would be to throw them 2
all away on the face of what they are.
3 3 MR. SIESS: You're not in research.
4 4 MR. EBERSOLE: Well, I guess that's one of 5 5 the reasons that I don't want to be in research.
6 6 MR. BENDER: What is your basis for the l 7 7 design principle to design something like this, to design a 8 8 seal that had to maintain a certain differential within the 9 internal pressure and the seal in research. And I'm 9
10 10's wondering if something like that was behind this.
O 11 11 MR. COSTELLO: Well, Mr. Ebersole has a 12 12 legitimate point of view in question, but I guess, you know, 13 13 we got to this after we got, you know, to the (inaudible) 147 e 14 because these are identified as having potential when
)
15 15 subjected to --
16 16 MR. EBERSOLE: Even under the best of 17 17 operational conditions.
18 -~ 18 MR. COSTELLO: And of course, you know who's
'19 ' 19 doing 1c, but that's the decision about whether we i 1
'20 20 (inaudible) or should have a particular (inaudible) having a l21 21 regulatory decision and we feel could stand problems. What
'22 22 is learned in the research? I don't know exactly how I feel l23 23 about it, but that just as (inaudible) to some of the l24 24 (inaudible) structural design of some parts of the 25 25 containments which are tolerant of overpressure, fg __
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1 overtemperature, so well may be these. But I don't think 2
you know well enough to say how much.
3 3 MR. SIESS: Well, if you find out by 4
4 increasing the pressure inside to 180 psi, say, you could 5 5 withstand the same pressure that the containment would take 6 6 under 140, 150. This is something regulatory people could 7 7 decide to require, assuming that that seal can take that 8 8 pressure and the system can be used to supply it.
9 9 If you find that it ain't going to leak in a 10 10 ~T severe accident no matter what you do, then it's a question V
11 11 for regulatory to decide that something has to be done about 12 12 it. But if you're concerned, as Jesse is, with the 13 13 reliability of the air system, either normal operation er 14 S 14 following a severe accident, that is a very good question; L ,i 15 15 unfortunately, it's not one that the structural engineering 16 16 branch is going to be able to answer.
17 17 MR. COSTELLO: Yes, sir. But --
18! s '
18 MR. SIESS: Maybe it should have been asked l 19 19 before you started this stuff. But --
20 20 MR. COSTELLO: Well, again, there is a 21 21 certain presumption that no idea have even be taken for
'22 22 conditions for which there are no regulatory structure --
23 23 1.e., LOCA conditions -- then it would be there, all you 24 24 would need to do is build it.
25 25 MR. EBERSOLE: It's a classic example of o J c) l laaNNlmw REPORTlNG r
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l compartmentalization of function.
2 MR. COSTELLO: I guess, you know, I would 3' 3 certainly go along --
4 4 MR. SIESS: Jesse, what should be done as 5 5 part of the IPE, the individual plant enamination, is 6 6 reliability of the air system for pressurizing these seals 7 7 should be a pa- t of the picture. And if they can't prove 8 8 that is reliable, or if these seals at 60 psi are not going 9 9 to take accident pressure, that's an IEEE vol.ierability to 10 one of the mitigating --
IQm -
d 11 MR. EBERSOLE: Isn't it true that the seals 11 12 12 will have to exceed containment pressure in any case?
13 13 MR. SIESS: That's what --
14 14 MR. PARKS: That is the feeling right now.
15 15 MR. WARD: No, not necessarily. It could 16 16 extrude up there and seal, couldn't it.
17 17 MR. EBERSOLE: Well, anyway, I was about to 18 18 say to foreshorten all this work, you could just first pump NqJ 19 19 the seals up to the pressure you need to hold them at the 20 20 maximum containment pressure and see if they burst and I 21 21 suspect they will.
22 22 MR. PARKS: The design pressure is 150 psi.
23 23 The internal pressure --
24 24 MR. EBERSOLE: Is 150.
25 25 MR. PARKS: Yes, sir.
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l MR. WARD: Who is the manufacturer of these 2 seals, Brad?
3 3 MR. PARKS: Press Ray.
4 4 MR. WARD: Well, what do they have to say 5 5 about it; do they have a body, a testator?
6 6 MR. SIESS: What did you just correct to say 7 7 150 psi?
8 8 MR. PARKS: The internal design, the internal 9 9 design pressure or internal pressure that these seals are 10 s, 10 designed for is 150.
\,._)
11 11 MR. SIESS: That is what they are designed 12 12 for?
13 13 MR. PARKS: That's what ? ey're designed for, 14,r3 14 I don't know --
l Li 115 15 MR. SIESS: No margin or is that with margin?
16 16 MR. PARKS: That is what they tell me it's 17 17 about.
l18-18 MR. SIESS: The manufacturer says you can i i
'id'# 19 operate them at 1507 l 20 20 MR. PARKS: Yes. He says this is the design 121 21 pressure.
22 22 MR. SIESS: But they don't --
'23 23 MR. PARKS: I don't know.
1 1
24 24 MR. SIESS: Plants don't use 150, 25 25 MR. PARKS: No.
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l MR. SIESS: Okay. So if you found out that 2
you had to go to 150 to keep these things from leaking, the 3 manufacturer says you could do it?
3 4
4 MR. PARKS: That's the understanding I have, 5 5 yes.
6 6 MR. SIESS: Now, whether you get the 150 from 7 7 a reliable supply is another type of question.
8 8 MR. PARKS: We talked about this a little bit 9 9 and I guess we'll go back through it. Okay.
10 The primary objective as we see it right now, at 1{a' )
11 11 least from the adequacy of the seals, I guess, is to 12 12 determine the required difference in the seal and 13 13 containment pressure, called delta here, to prevent leakage.
14 ") 14 (Inaudible) the on psi, (inaudible) seals how high f) 15 15 can the containment pressure go on befcre you get leakage.
16 16 That's objective 17 17 No. 1.
18 w 18 The second objective is to get some sort of 1 ~ 19 measure of. We have for a smaller difference in heat 20 20 pressure.
21 21 Finally, this is a very (inaudible) test matrix 22 22 that we have right now. The plant analysis, there are four 23 23 different inflatable seal tests. Two using unaged seals and 24 24 two using aged seals.
4 25 25 The test number of the aging that will be applied p _ - - .
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l to the seals is still a little bit up in the air.
2 MR. SHEWMON: You measure the lobide pressure 3 3 or what?
4 MR. PARKS: We will measure those -- run a 4
5 5 pressure check to see amount of leakage for a certain given 6 differential pressure between the seal and the external.
6 7 7 MR. SIESS: Always with air?
8 8 MR. PARKS: That's the current test plan, 9 9 - yes. The reason for going with air instead of, I suppose 1C 10 you're thinking steam?
11 11 MR. SIESS: Whatever might be in the 12 12 containment, yeah.
13 13 MR. PARKS: The EPDM materials placed on the 14-s 14 seals and gaskets have simply limited, similar behavior, 15 U 15 whether it's air or steam.
16 16 MR. SIESS: Even in its response to 17 17 temperature?
18- 18 MR. PARKS: Yes.
19 O 19 MR. EBERSOLE: What does EPDM mean?
20 20 MR. PARKS: Ethylene Propylene Rubber, or 21 21 whatever.
22 22 MR. SIESS: Go back about four slides and 23 23 spell it out.
24 24 MR. EBERSOLE: That's okay. I missed that.
25 25 MR. SHEWMON: You've told him all he wanted O 1mw N=
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l to know.
2 MR. PARKS: The first two tests would be done 3
3 using air pressure and temperature; then the second two 4
4 tests would be done using the same sort of steam as the 5 5 first two tests except the temperature would be increased to 6
6 400 degrees Fahrenheit.
7 7 MR. SIESS: What duration? l l
8 8 MR. PARKS: The duration of the test?
9 9 MR. SIESS: Yeah.
10 10'l MR. PARKS: It would be as short as possible.
wJ 11 11 We planned to do certain gyrations for the internal steel 12 12 pressure and the external pressure.
13 13 MR. SIESS: Well, 400 degrees, if it's only l 14,) 14 on for 10 minutes, does it really make that much difference?
\-)
15 15 You won't get the degradation -- oh, some of them will 16 16 already be aged.
17 17 MR. PARKS: Yes, sir.
18-s 18 MR. SIESS: Then what's the reason for the
- r. yi
'19 19 temperature difference if they are already aged and they
'20 20 won't really age any more during the test?
,21 21 MR. PARKS: The thing is, is the material may 22 22 soften, mechanical, computerial properties may soften l23 23 somewhat due to the operating temperature and that may l
l 24 24 implant them --
25 25 MR. SIESS: See if you can determine that 7-3 _ __.__
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without the benefit of this test period and could do it in a 2 testing machine?
3 3 MR. PARKS: We could determine the amount of 4
4 salt but I don't know if we could determine how that 5 5 infringes the leakage though.
6 6 MR. SIESS: Doesn't the aging involve 7 7 temperature?
8 8 MR. PARKS: Yes.
9 9 MR. SIESS: If you age them for 168 hours0.00194 days <br />0.0467 hours <br />2.777778e-4 weeks <br />6.3924e-5 months <br /> at H3 1{',/~} so many degrees temperature in the amount of 15 minutes 11 makes any difference or 11 ...
12 12 MR. WARD: No, that's not his point. It's 13 13 just a seal temperature, whether it's been aged or not, is 147 s) 14 going to have different properties.
'u/
15 15 MR. SIESS: Might have a different.
l 16 16 MR. WARD: The last one is 400 degrees F.
,17 17 MR. EBERSOLE: On the matter of properties, 18 3 18 this stuff is what you call tightchested; that is they batch
?
I d"'l to test a batch of this and make a bunch of seals. Do you go 20 20 back and determine the 0/A on the batch-testing process?
21 21 You don't do the reliability of the recipe?
22 22 MR. PARKS: No.
23 23 The last --
24 24 MR. SIESS: What's the status of those tests?
25 25 MR. PARKS: Okay. All the preliminary test a mNNmw U
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l planning fabrication of test fixtures have been done. I 2 guess the current status is they are on hold pending 3 additional funding.
3 4 MR. SIESS: Oh , they have, that's for our '88 4
5 5 budget?
6 6 MR. COSTELLO: No, sir. We're not 7 7 overbudget. This is for '89.
8 8 MR. PARKS: Okay. The last topic is that of 9 bellows. As I mentioned earlier, we have just begun looking 9
10 ig~'; at bellows. At this point we have done a preliminary fairly
,)
11 11 comprehensive, I guess, of available technical literature on n'
12 12 bellows. From our surveys we've done, it seems like there 13 13 is two main categories of bellows that occurred at 14 containment penetration. The first type is a vent line 14g 15 15 bellows, only under Mark-I containments. These bellows are 16 16 anywhere from 65 to 90 inches in diameter, a very huge 17 17 structure.
18 q 18 The other common type of bellows, what I already V
19 19 categorized as process piping bellows, they are normally 20 20 from 18 to 36 inches in diameter and normally occur at the 21 21 penetration for this steam and feedwater lines.
22 22 MR. SIESS: What material are these?
23 23 MR. PARKS: Stainless steel.
24 24 Take a look at a typical Mark-I containment 25 25 (inaudible), each of those past bellows that I've described, f
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l The vent line bellows occur at the actual penetration of the 2 And that would be vent lines into the suppression chambers.
3 in this area here, over here and there is normally eight 3
4 4 vent line bellows around the perimeter of the containment.
5 5 Also, as I mentioned, you also have bellows at 6 6 these penetrations for the feedwater and mainstream bellows.
7 7 Here is a typical detail of a vent line bellow 8 8 which penetrates the suppression chamber at around 55 to 9 9 90 inches in diameter, normally, two bellows, side by side 10 here.
IC- )
%J 11 Why isn't that symmetric top to 11 MR. SHEWMON:
12 12 bottom? That's that top horizontal member outside?
13 13 MR. PARKS: This (indicating)7 14 14 MR. SHEWMON: The straight line, right by 15 15 your fourth finger up there.
16 16 MR. SIESS: Right under expansion bellows.
17 17 MR. PARKS: Right here?
18 s 18 That's an error in the drawing. It should be --
()
19 19 MR. SIESS: You've got the same error four 20 20 times on the next one.
21 21 MR. WARD: That's a sleeve around the bellow 22 22 section?
23 23 MR. PARKS: This is the projected shroud 24 24 around the perimeter of the bellows.
25 25 MR. MARK: Is that bellowed material metal or l
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I something of plastic?
3 2 MR. PARKS: Stainless steel metal.
3 3 MR. EBERSOLE: There is nothing to keep 4
4 flying articles from coming from the inside of the 5 5 suppression chamber and coming down and intercepting the 6 6 bellows, is there?
7 7 MR. PARKS: Not that I'm aware of.
8 8 MR. EBERSOLE: If I drop a wrench down there, 9 9 I'm not going to get normal bellows performance, am 17 10~', 10 MR. PARKS: There's nothing to stop it from J
11 11 going downward.
12 12 MR. EBERSOLE: You have other protective 13 13 guards there? It is a downward tilt, and the first thing l14 s 14 that would stop it would be a convolution.
l,_)
- 15 15 MR. PARKS: Probably.
16 16 This is the other type of bellows, as typically 17 17 found in penetrations, that is the process pipe inside l 18 - 18 metal. Here they have a protected shroud between the
)
l19' 19 process pipe and the bellows just in case the process piping 20 20 burst, so that you don't damage the bellows here. Then you 21 21 see the outside or external (inaudible) goes around the 22 22 perimeter of the process pipe.
23 23 MR. SIESS: Both of those are BWRs. Do you 24 24 have similar things like this for PWRs?
25 25 MR. EBERSOLE: Well, the difference there is n _____
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I that one is going to move a lot, isn't it, in contrast to l 3 2
the suppression group beliows; that is going to move with up 3 3 and down temperature of the steam pipe? That's what it's 4
4 there for, yes. But the other one is just there; but this 5 5 one is going to work.
6 6 MR. PARKS: Well, in the event of a severe 7 7 accident, the other one --
8 8 MR. EBERSOLE: But that's a one-time shot.
9 9 MR. SPARKS: (Inaudible) during normal 1p 3 10 operation.
O i
l 11 11 MR. EBERSOLE: So what's the fatigue line for 12 12 the convoluted?
13 13 How do you monitor it?
l
' 14 ~3 14 MR. PARKS: That's a good question.
L) l 15 15 MR. EBERSOLE: You have got covers on it.
16 16 MR. SHEWMON: Is that containment?
17 17 MR. SIESS: Yes, sir.
18 s 18 MR. SHEWMON: I don't see containment leaks
', )
I 19 " 19 up there.
20 20 MR. PARKS: Finally, if we look at this, this 21 21 is a very tentative type of test sequence that we may or may 22 22 not employ, depending on (inaudible) future work. We may, l 23 23 for the future, with additional investigation, determine l
'24 24 that a test is not (cough). If we do a test, follow this i25 25 sort of sequence here, start off with axial compression of
,\ . - _ .
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the bellows, with axial compression only, apply internal 3 2 pressure only or bending the bellows. Also lateral 3 3 deflection. Each one of these independent of the other.
4 4 And at each point, compare what the results of our test data 5 5 with the results (inaudible).
6 6 MR. SIESS: Will these be cycle loads, 7 7 fatigue loading or is thic just . . .
8 8 MR. PARKS: What the plans are now is it 9 9 would be either -- no it would not be a cyclic load, it 1 10 would be to apply a given amount of deformation and measure 11 11 the strength compile more deformation and do the same thing.
12 12 MR. SIESS: Just measure the load deformation 13 13 characteristics onto those different loads?
14 14 MR. PARKS: Yes.
15 15 MR. SIESS: What is that doing -- oh, just to 16 16 check out your analysis?
17 17 MR. PARKS: Right.
18- 18 MR. SIESS: But then that has not failed.
19 b 19 How doen the tellows fail? That's what we are interested 20 20 in, isn't it, the failure of the bellows?
21 21 MR. PARKS: That's exactly right.
22 22 MR. SIESS: How do bellows fail?
23 23 MR. SPARKS: By any of these --
24 24 MR. SIESS: How do they fail? Back off from 25 25 the slide and tell me how they fail? What happens to them?
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MR. PARKS: That depends on the loading. An
)
2 axial compression, it may be by bending of the external 3 3 convolutions.
4 Push it together till it 4 MR. SIESS:
5 5 convolutes and cracks.
6 6 MR. PARKS: Right. By internal pressure, 7 7 it's -- the bellows are expanding and again you would get a 8 8 rupture most likely of the internal convolutions from 9 9 buckling and cracking.
10 10~T MR. SIESS: Each one will be tested for
() 11 11 failure of that mode?
12 12 MR. PARKS: Well, again, if I may be very 13 13 candid, that's not the current plan. This is to check out 14 7 14 our analysis, mostly. We're still trying to stay elastic, i._.)
15 15 MR. SIESS: But your bellows is then, what, 16 16 trying to produce deformations, not failure?
17 17 MR. SPARKS: At this point, yes. If we move 18 s 18 down to Item E here, then we would apply some normal design
( )
19'~' 19 combinations of A, B, C, and D. Okay. And again check out, 20 20 we wouldn't expect failure there to check out our analysis.
21 21 And then finally, at Item F here, we would apply a severe 22 22 accident combination of the first four items. Exactly what 23 23 amount of actual deformation internal pressure that we have 24 24 in a severe accident, we would have to determine over 25 25 another global analysis of the overall containment, I would n _ _ _ - -
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1 think.
3 2 MR. SIESS: So you're going to do an elastic 3
3 analysis and validate it by making an elastic tests, tests 4
4 within the elastic range.
5 5 MR. PARKS: Basically, yeah.
6 6 MR. SIESS: Solely until the analysis, modify 7 7 the analysis, predict the elastic behavior; and then you're 8 8 going to test it for failure, and then go run the analysis 9
9 then because obviously it doesn't fail elastically, does it?
10 19 T MR. SPARKS: No, I wouldn't anticipate
(.) 11 11 elastically.
12 12 MR. EBERSOLE: Let ask you --
13 13 MR. SIESS: I don't see where you are going?
14 MR. EBERSOLE: -- about, in view of the fact l
1('_') x.'
l15 15 we still live right now with pipe failures, if you have a 16 16 mainsteam failure or people with pipe failure, these things 17 17 don't take any (inaudible) to speak of. Are there other
'1 18 supports that constrain the motion of the pipe so you don't 19 19 have to ruin these?
l 20 20 MR. PARKS: Not that I'm aware of, no.
l21 21 MR. EBERSOLE: Well, what happens to these 22 22 delicate bellows if you have a pipe break? Does it destroy l23 23 the containment and who cares? I suspect that's the case,
'24 24 isn't it.
25 25 MR. COSTELLO: That's the reason of the guard g _ . _ _ _ _
(J --
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2 MR. EBERSOLE: Now, that doesn't take the 3 3 load off. I'm looking at the guard pipes here, the load, 4 the motion would be seen by the bellows; the guard pipe just 4
5 5 fits the water back into the containment, it doesn't carry a 6 6 load other than that. If you look at the fourth lines, it's 7 7 straight through the bellows. But there may external 8 8 brackets out here, or ears on the pipe to minimize axial 9 9 motion. I don't know. Do you look at that sort of thing, 10 performance of the bellows in emergency modes like that?
10q)3 11 11 MR. PARKS: We will, but sometimes we --
12 12 MR. EBERSOLE: We just got started.
13 13 MR. COSTELLO: Well, he's a little premature 14 -x 14 to put the --
LA 15 15 MR. SIESS: What Jesse is talking about is 16 16 loading. You come down to severe accident combinations, you 17 17 know, what is the loading in a severe accident. It's not 18 \ 18 just pressure.
\
19 ~) 19 MR. EBERSOLE: Really not a severe accident, 20 20 Chet, it's just a routine common design.
21 21 MR. BENDER: I think it would be a good idea 22 22 for you to talk to one or more of the architect / engineers 23 23 about how they will use these. Most of these arguments that 24 24 are coming up here are not new questions. They have been 25 25 around for a long time. And there are some design n _ . _ _ _ _ _ .
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I principles involved in how the bellows are installed. And 2
also some looking has been done, hard pressure releases into 3
3 these small areas where the bellows fit around the guard 4
4 pipe. So, you might be well advised to get that information 5 5 before you take off on your own.
6 6 MR. EBERSOLE: In regard to BWR in 7 7 particular, these are stainless steel, you said?
8 8 MR. SPARKS: Yes. l l
9 MR. EBERSOLE:
9 So the old stress corrosion 10 1[ ; matter now is enhanced because of the thin cross-section.
11 11 MR. SIESS: I think you have two things 12 12 there. You also had some low cycle fatigue on these things 13
, 13 as they operate. They may be degrading.
l 1 \
14 14 Under normal design combinations, that's not just l
,15 15 normal temperature, that would include a pipe break like 16 16 this (inaudible).
17 17 I mean, pipe breaks come with a normal design.
18 3 18 Plants are designed for pipe breaks all over the place; up (j
- 19 10 to and included through the double ended (inaudible).
20 20 MR. EBERSOLE: What keeps this fluid being --
21 21 will keep the steam off of the bellows.
' 22 22 MR. COSTELLO: I guess the point that drives 23 23 all this is that there is a concern that all bellows are a 24 24 (inaudible) after all. Axial motion that some large l25 25 deformation associated with severe accidents, loading, may 1
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well impose transfer shear and the --
2 MR. SIESS: Suppose we could design a 3 containment that would take 4 or 5 percent strain, does that 3
4 4 have to be absorded in these bellows?
6 MR. COSTELLO: Yeah.
5 6 If this things moves out a foot?
6 MR. SIESS:
7 7 MR. COSTELLO: Yeah.
8 MR. HORSCHEL: Was it solely the bellows; 8
9 didn't it also havo a convoluted pipe test --
9 10 Right. A little bend of a MR. COSTELLO:
1{'yi }
11 11 pipe.
12 12 MR. SIESS: And some of them have a pipe 13 13 restraint, too right around the bend.
If(3\_ /
14 MR. HORSCHEL: That is going to really vary 15 15 from containment to containment. It's not a generic thing; 16 16 you're going to have to --
17 17 MR. SIESS: But you could get very large 1 18 axial deformations under a severe accident condition. You 19 19 can get very large lateral deformation from the broken pipe 20 20 conditions, I guess.
21 21 Now a pipe break, if it doesn't lead to a severe 22 22 accident, we're not all that worried, not that much 23 23 radioactivity.
24 24 MR. COSTELLO: I guess you're aware, as far 25 25 as dog ears taken out, they begin, (inaudible) I guess where O maNNmW REPORTlNG SERVlCE a record of excellence
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l to point out a number of things, (inaudible) into it, trying
' 2 to get into the process of what these things are actually 3 3 designed to tolerate. And then, if there is a question 4
4 about whether an analysis can take you from what they are 5 5 designed to tolerate to what exactly they want to 6 6 (inaudible), then, if the analysis won't carry it, we may 7 7 have to do a test.
8 8 MR. SIESS: Now, if that penetration is a 9 9 pipe through a PWR, through a containment, does that pipe 10 10 3 have an isolation valve? Doesn't it have to have an U
11 11 isolation valve?
12 12 MR. EBERSOLE: Yes, they've got isolation 13 13 valves. It occured to me when I look at this, if you have a 14r; 14 failure upstream on the mainsteam isolation valve, you still
()
15 15 may tear a hole out of the containment.
16 16 MR. SIESS: On the upstream pressure?
17 17 MR. EBERSOLE: Unless you fix the pipe so it 18 x 18 won't move, tear out the bellows.
? )
, i f ~^ 10 MR. SIESS: Then you have a downstream 20 20 isolation value; but if the bellows fails, it doesn't do any 21 21 good. Right? The only way you can isolate a bellows l
l 22 22 failure is with the upstream valve.
23 23 MR. EBERSOLE: Well, Chet, if the failure 24 24 varies in front of the upstream valve, you will get an axial 25 25 load on these bellows unless it's fixed by mechanical lugs U-~ man Nm REPORTlNG SERVlCE a recmri of excellence
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1 or stopped somewhere besides the bellows. Otherwise, it's 3
t 2 got to take the thrust. And I suspect it will not do it.
3 3 There must be anchors. I don't know that, 4 4 but . . .
5 5 I can't imagine --
6 6 MR. SIESS: He's figuring out what the l
7 7 scenario is for this because, you know, let's face it, if 8 8 the steamline (cough) BWR, that's really not a severe 9 9 accident yet.
10 MR. WARD: But I think Mike's got a point, 10-11 11 there probably has been some looking at scenarios and 12 12 against the performance of the bellows, and you might not 13 13 have to start from the ground zero to figure this out.
14 ~x 14 MR. SIESS: I'm not sure you're going to find L]
15 15 different mechanical scenarios for a severe accident or for 16 16 a normal accident, except if you can let your containment 17 17 move a lot. Now, we limit it to a 2 percent strain and we 18 - 18 took the studs out, it might go to 6 percent strain, and
( ;
19' 19 that's a pretty good piece.
20 20 And you're limited by the yield strength to the 21 21 pipe, aren't you?
22 22 That's pretty large compared to the bellows, isn't 23 23 it? If you straighten those bellows out, you're not going 24 24 to take the yield strength of the pipe.
25 25 Has there ever been a bellows failure?
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1 MR. COSTELLO: Not a bellows.
- 2 MR. WARD: Of any sort?
3 3 MR. SIESS: Well, we had some in the 4 4 condensor system, but I thought those were some sort of 5 5 (inaudible), not metal.
6 6 MR. BENDER: Research water system in the 7 7 condensor water system.
8 8 MR. SIESS: Yeah. Was that metal?
9 9 MR. BENDER: No, it was rubber, 10 1{ mq MR. WARD: In other industries, there have a
11 11 been failures of stainless steel bellows. I don't know 12 12 about any of this size, but 16 inch.
13 13 MR. COSTELLO: That was one thing we would 14 14 like to talk with you because one of the paths was
'15 15 (inaudible). One of the paths that (inaudible) is 16 16 experiencing in the process industries. And it's a good 17 17 source of work for (inaudible), of that kind are recorded, 18 18 or has it just arrived?
l19 19 MR. WARD: I don't think there's any second 20 20 opinion of good sources.
21 21 You know Rodebaugh is -- you know him?
i
!22 22 MR. COSTELLO: Yeah.
23 23 MR. SIESS: He's probably got a handle on l24 24 more of that sort of stuff than anybody else.
25 25 I think that this covers everything you had had on O liENNN llEPORTING l SEliVlOE a record of excellence
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your list except the steel containment and seismic capacity.
2 Am I right?
3 MR. COSTELLO: Yes, sir.
3 4
4 MR. SIESS: And as you pointed out, we had 5 5 talked from time to time about this item that appeared on 6 6 our agenda of the applicability of mo(sling and testing for 7 7 full-scale containments.
8 8 MR. COSTELLO: Yes, sir. I had prepared --
9 9 well, there are two aspects we were going to speak to that.
19' , 10 One was to have Mr. Clauss talk about what has transpired in G
11 11 the application of Sequoyah, which is something that is, in 12 12 fact, done. And ' hen you're going to be treated. That's 13 13 not why we're leaving a track of how it was going to work 14 just as well for concrete containments. Sometimes if you 1(; - ]
\ /
15 15 would care to see some facts or some (inaudible), we would 16 16 be pleased to accommodate you.
17 17 MR. SIESS: I think it's getting pretty late 18 18 to talk about that now. Maybe we can have a meeting 19 19 sometime in Washington?
20 20 MR. COSTELLO: Yes, sir. I would be glad to.
21 21 MR. SIESS: It seems to me that it's still 22 22 not entirely clear what the real questions are that we're 23 23 trying to get at here. And how are we going to use this 24 24 stuff for managing severe accidents.
25 25 Obviously, we're not going to use to prevent any l
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l accidents. Use it for venting releases hopefully, but not 2 And I hear of different for preventing severe accidents.
3 3 things from different people. And as you say, NRR doesn't 4
4 really know what it wants.
5 5 MR. COSTELLO: I didn't say that, sir. I 6 6 said it's hard to know who NRR is because the generic issue 7 7 of NRR is now exposed.
8 8 MR. SIESS: I think that there's going to be 9 9 a real effort made by the research to get together with 1 to whatever levels are necessary, including NRR to see just 11 11 what you're going to be able to do with the information 12 12 you've got or what kind of information they need. I think 13 13 they need to manage severe accidents. And if the PRA people 14e) 14 since they want to know the ultimate, structural capacity 15
(> 15 with uncertainties, you know, that's almost impossible to 16 16 answer.
17 17 MR. COSTELLO: I would say, to answer in the 1 18 way a structural engineer like myself would like to answer a 19 19 question. However, when you have a caveat with 20 20 uncertainties in there, our recent experience and 21 21 interactions on the 1150 exercise has shown that the -- an 22 22 answer which is -- well, it could be Mode A or Mode B with 23 23 ranges of P plus or minus 20 psi, and some weighting for 24 24 Mode A versus Mode B based on the calculations that you feel 25 25 you can do, suffices, it seems, for the risk analysis O -_-_
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purposes because that's enough -- that fits in the grinder 2
and it seems to suffice. So that's comforting.
3 MR. SIESS: But, Jim, I think any competent 3
4 4 structural engineer could look at what you've done 5 5 analytically, what you've done experimentally, and maybe 6 6 what the British have done and Canadians have done, and to 7 7 give a number with a third degree of confidence with a good 8 8 lower bound figure, like -- you know, pick 125 off of the 9 9 curves or whatever. But I don't think any structural 10 19 , engineer, average design-type structural engineer could give n-11 11 with any confidence the level at which it will fail for the 12 12 structural integrity will be lost.
13 13 MR. COSTELLO: That's true, but that's not 1 14 the question that has been asked by the PRA people. They 15 15 don't want you to --
16 16 MR. SIESS: I think that's what ought to be 17 17 re-examined at NRC because if they start going into a 18 ,
18 research program that wants to establish the mode at which 19'~ 19 structural integrity will be lost, this is a program which, 20 20 in my mind, will approach that we spent on LOCA ECCS.
21 21 MR. COSTELLO: What do you think they're 22 22 esking for?
23 23 MR. SIESS: That's what he thinks they're 24 24 asking for.
25 25 MR. CLAUSS: There are two people we're U maNNmw REPoliTlNG SERV 10E l a recmd of excellence
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1 trying to address ourselves. An'd from what I hear from this 2
group today, generally, what you see as real value in this 3 3 program is addressed to the management (inaudible). And for 4
4 that, we need to know with confidence the pressure at which 5 5 the containment will not fail. And that's all we need to 6 6 know. And that's a pretty simple problem. But we're trying 7 7 to go beyond that to address ourselves as a group. You're 8 8 supposed to do this in PRA. And right now (inaudible) about 9 9 1150. And we have been asked to help those people and we 10 10 have interacted with them.
11 11 They want to know a lot more than (inaudible).
12 12 They need to know a range of failure pressure, they need to 13 13 know what their mode is. In a BWR, fcr instance, it's 14 14 important to know whether the failure involved bypass or not 15 15 because that has a source term. So they need to know a 16 16 location of failure, they need to know what the range of 17 17 pressures is that that failure might occur over, and they 18 18 would like some failure size.
19 O 19 MR. SIESS: Well, let's take those questions, 20 20 and what the next step should be in having you research is 21 21 to look at what research would have to be done to answer 22 22 those questions.
23 23 MR. CLAUSS: Oxay. You want to answer the 24 24 questions with certainty.
25 25 MR. SIESS: What's the probability in trying O
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l to search for these successful and what's the cost?
2 And my feeling is that somebody has got to --
3 somebody else has to do it.
3 4
4 The cost will be high to get that probability of 5 5 success (inaudible) at an acceptable level. It may be much 6 6 too high to justify.
7 7 Now, this is an approach I've seen other people 8 use. They've looked at the problem, laid out a research 8
9 9 program, evaluated the probability of that program 10 10~') succeeding and estimated the cost. I think that lowering
.)
11 11 the level of -- raise the level of confidence to something 12 12 that's meaningful, it would be a tremendous (inaudible) 13 13 because that depends on details. And there are too many 14 14 differences of details in the containments around here now.
15 15 MR. CLAUSS: I think we've already raised it 16 16 to a level such as (inaudible). For instance, you know, you 17 17 need to make a qualitative judgment. We're not asking for a 18- 18 determinant number of, tell me exactly what the pressure in
( )
19 19 itself. That's not what they need. They need value 20 20 judgment. They need to know, is there a chance that 21 21 equipment that has leakage could occur before close rupture 22 22 of the shell.
23 23 MR. SIESS: Sure, there's a chance.
24 24 MR. CLAUSS: Well, we could have found out 25 25 there was no chance. We could have found out that these n _ - _ - _
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I structures fail always at 1 percent strain. You don't 3 2 develop large enough deformation to (inaudible) go ahead and 3 3 find that.
4 4 MR. SIESS: Of course, you're talking about 5 5 when it doesn't fail.
6 6 No, I'm not.
MR. CLAUSS:
7 7 MR. SIESS: You're on my side.
8 8 MR. COSTELLO: Well, as I say, the one thing 9
9 will surely happen before the other. You could say that 10~ ', 10 with confidence. Now, I think -- let's look back on the w) 11 11 scale. I don't want to burden the Subcommitee too much, but 12 12 as far as the research -- as far as the steel part of it is 13 13 done -- I say done is done. I say we have demonstrated that 14 1 0T as far as the PRA kind of questions that are being asked G
15 15 now, we've learned enough to be able to satisfactorily 16 16 provide input for that mil. And I think (inaudible) the 17 17 other side of town earlier this week with the exercise 1 18 numerous experts who used what they learned from the tests, 19 19 applied their judgment for certain specific plants in the 20 20 exercise.
21 21 MR. SIESS: What could you say about when a 22 22 steel containment will fail?
23 23 MR. COSTELLO: What can we say?
24 24 MR. SIESS: Yeah.
l25 25 MR. COSTELLO: We can say that if you've done l O wNNmW REPORTlNG SERVlCE a recorri of excellence
22L I an axisymmetric analysis and if you examine the details and 3 2 found any weak links, you can check the weak link against --
3 3 MR. SIESS: Being a (inaudible) weak link?
, 4 4 MR. COSTELLO: Sure. A nice healthy strain 5 5 concentrator, and we know what to look for by now.
6 6 MR. SIESS: Now, having found that strain 7 7 concentration, you can predict what it will fail at?
8 8 M R ., COSTELLO: You can have a pratty good 9 9 choice of chasing that to see if something else will fail 1p- 10 before that. You can also have a pretty good idea how -- to V
11 11 though check. whether you would, it would at least allow you 12 12 or not.
13 13 And I think -- it's not something that can be done 14! '3 14 on the back of an envelope. But neither in the likely use
/
15 15 in the IPEs, should be back of the envelope. Utilities are 16 16 going to reasonably be asked to look at their own (cough).
17 17 The tools are out there so that it can be done.
18- 18 MR. SIESS: Do you think you can give them a id 19 list of things to look for?
20 20 MR. COSTELLO: Oh, I think those who have 21 21 been aware of what is going on and have followed results 22 22 have figured it out pretty well themselves.
23 23 MR. WARD: Well, can you give them a better 24 24 list than you could have five years ago.
25 25 MR. COSTELLO: Yes, sir. And we're not quite p ---
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there at that stage on the concrete containments, but I hope 2
we will be.
3 3 MR. SIESS: In the IPE, they'ru going to 4
4 predict a failure t.oad.
5 MR. COSTELLO:
5 Or a nonfailure load.
6 6 MR. SIESS: Are you accepting either one?
7 7 MR. COSTELLO: The good part about the 8 8 nonfailure load, if you know more is that you have more 9 9 confidence that you haven't missed a f ailure lc ad.
10 MR. SIESS: With respect to the failure load I P -)
11 11 down to zero and the level of confidence leaving out open 12 12 valves and things of that sort, the higher you go, the i 13 13 broader the band becomes.
14 14 MR. COSTELLO: The band doesn't come at a
'15 15 broad -- they don't -- it's not a continuous function from 1
16 16 zero. In fact, you start getting certain jumps in there.
17 17 And when you get out well in the inelastic range (inaudible) l 18m 18 to widen.
L i 19' 19 MR. SIESS: That's the part I'm concerned l 20 20 about.
21 21 MR. COSTELLO: But --
22 22 MR. SIESS: My idea is that fou stop at the 23 23 point where the band begins to get largo, when new
- 24 24 confidence begins to get lower. That's what I'm talking l
l 25 25 about, high confidence and no failure.
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MR. COSTELLO: I think for the (inaudible) 3 2 management, that's exactly what you want.
3 3 MR. SIESS: Yes.
4 4 MR. COSTELLO: But, again --
5 5 MR. SIESS: But when are you going to give 6 6 the PRA7 Are you talking about IPE, down at PRA.
7 7 MR. COSTELLO: Uh-huh.
8 8 MR. SIESS: Are you using those 9 9 interchangeably?
10 1Q MR. COSTELLO: I believe the IPE --
11 11 MR. WARD: That's what it is.
12 12 MR. COSTELLO: Yeah. We'll be a (inaudible) 13 13 exercise. And I think, again, I've -- I'm not going to 14q 14 stand here in warranty that the IPE activity will be that --
(/
15 15 will be the salvation of the republic.
16 16 MR. SIESS: What would you like? How would 17 17 you calculate the failure pressure of a containment that had 18 18 channels and angles instead of studs?
19 O 19 MR. COSTELLO: Well, see me next year. But I 4
20 20 do believe -- and the (inaudible) will swear on a stack of 21 21 bibles -- that the channels and angles are -- would give you
, 22 22 the machine failure mode evet better than a stud.
23 23 MR. SIESS: What's the machine failure mode?
24 24 MR. COSTELLO: (Inaudible) You know, these 25 25 are the ones that's been arguing for years. His argument is O ---
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I that rigid -- more rigid embedment will lock that end of t.
- 2 plane even tighter than (inaudible) concentration. That's 3 3 his argument that remains to be seen, and there has to be 4 4 some more analyses on the checking of his calculations.
5 5 MR. SIESS: Want to block it in the 6 6 (inaudible) row of studs of two inches? I doubt if they 7 7 block it much more than that (inaudible) two inches, it 8 8 produced a tear.
9 9 MR. COSTELLO: I simply respond to your 10 10 % question than that. But I think we're sorting out.
.U 11 11 MR. SIESS: So if I had an angle like the 12 12 location of that row of studs, you would say, what, 13 13 2 percent straining it will fail?
14 14 MR. COSTELLO: I wouldn't be too premature 15 15 until I saw some calculations, but I believe that's one of 16 16 the things we need pursuing.
17 li MR. CLAUSS: If you give a range, though,
- 18. 18 you're central (inaudible) around 2 percent straining, that
(
19 19 pressure correspondences to 2 percent strain in the field.
20 20 But you don't have confidence in that, to say that's the l 21 21 number.
22 22 It could go to 4 percent (inaudible) or it might 23 23 go at a half a percer.t.
24 24 MR. SIESS: You know, most engineers when 25 25 they run into a situation where they have low confidence, 1
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l they try to get around it by doing something --
2 MR. CLAUSS: If you're denying structure, t
3 But that's not what we're trying to do. We're not 3 yes.
4 4 trying to design.
5 5 MR. SIESS: I'm trying to look at the 6 6 containment capacity and saying I have no confidence in the 7 7 ultimate capacity, ultimate structural integrity level, so 8
8 I'm going to try to pick a number that I do have confidence 9
9 in and learn to live with it.
10
, 1P N. MR. CLAUSS: For (inaudible).
N_)
11 11 MR. SIESS: No, again. (Inaudible) it in 12 12 deciding on whether plants are safe, deciding on whether 13 13 they need the (inaudible) program, and then I'm going tc 14 14 look at a high confidence, low probability of failure and g
15 15 base my regulatory approach on that.
16 16 MR. WARD: In deciding when a plant is safe, 17 17 you need to know about the failure modes. What's safe?
18 s 18 MR. SIESS: But if I know the failure mode
()
19 19 with a very high uncertainty, what do I know?
20 20 MR. CLAUSS: If you're going to -- you know 21 21 more than you did before you did that.
22 22 MR. SIESS: No, I don't. You just think you 23 23 do.
24 24 Give me a (inaudible) up here with a spread on it 25 25 like that at a confidence level of 20 percent, (inaudible).
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1 You're just kiddir.g yourself. You've got a number, but low 3
2 confidence. That's no number.
3 3 MR. CLAUSS: Chet, you (inaudible) have to 4 4 know something about the failure mode. Wouldn't you agree 5 5 that --
6 6 MR. SIESS: There's no failure and level; 7 7 they're two different things.
8 8 MR. CLAUSS: Okay. Let's talk about the 9 9 failure mode then. How do you approach that?
10 To understand the failure mode, you have to make 10~x G
11 11 some assumptions about the failure level.
12 12 MR. SIESS: No. I look at only the mode. If 13 13 I have confidence that the failure in the mode is going to 14 be a leak before break, I might be willing to raise -- lower 14 eT,
')
15 15 my confidence levol on my value I want to look at. And if I 16 16 think it's going to be explosive, I'm going to work a lot 17 17 lower than that, higher confidence at a lot lower level.
18 . 18 That's how the mode is affected, I think.
()
19 10 MR. COSTELLO: I think there ought to be --
20 20 MR. SIESS: Well, not structurally, but 21 21 regulatory.
22 22 MR. CLAUSS: If you do that in a safety 23 23 context where you're trying to evaluate safety, you're 24 24 really biasing your results. Because if you do that in a 25 25 safety context, you're biasing your results completely.
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If you chink it's going to be ruptured, the 2
& ability of failure is ruptured, and you give yourself that 3 much more modeling, well, you may be asking that --
3 4
4 MR. SIESS: But we're doing this all the 5 5 time. We let an uncertainty dominate the whole system. If 6 6 it's a high uncertainty, we're more conservative. We're 7 7 looking at a NUREG-150 with uncertainty bands like this and 8 8 But they don't know. They look at the bottom.
(inaudible).
9 9 Watch them.
10 1(, N) MR. COSTELLO: I guess the only suggestion 11 11 I'm going to have is again my suggestion that the venting 12 12 scheme is being developed in Germany where they're proposing 13 13 letting go at not much more than design pressure, 1( ;. 14 notwithstanding the fact that 150 percent of the design 15 15 pressure is given.
16 16 MR. SIESS: And they don't seem to need to do 17 17 research.
18 18 MR. COSTELLO: They have.
19 19 MR. SIESS: They got our high confidence.
20 20 MR. COSTELLO: No. In fact, I'll make this 21 21 statement. The principal beneficiaries cf the USNRC and 22 22 research program on steel containments were the Germans.
23 23 MR. SIESS: Sure.
24 24 HR. COSTELLO: They were the principal 25 25 beneficiaires because they put their own resources in to g _
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they put the money in and did the work as opposed to 3
3 standing and waiting.
4 4 MR. SIESS: We did come tests on the 5 5 (inaudible) site that showed that when the thing went out a 6 6 foot or two and hit something and it ruptured. But there 7 7 are regulatory philosophies that severe accidents are 8 8 residual risks. Let's do what's reasonable to fix it.
9 9 We've put in vents with filters and we've vented one and a 10 half times the design pressure (inaudible).
1{-]
\
11 11 MR. WARD: Those vents are with (inaudible) 12 12 they are putting in our --
13 '3 And you know they are?
14 14 MR. WIESS: Not quite.
15 .5 MR. WARD: They have no basis --
16 16 MR. SIESS: We've been into that situation 17 17 where it's been vented through the filters and the 18 18 consequences won't be too bad. And since they take that 19 19 approach --
20 20 MR. WARD: I sure don't want to see cosmetic 21 21 filtered vents on 120 U.S. reactors. What a waste of 22 22 research.
23 23 MR. SIESS: You think filters are cosmetics?
24 24 MR. WARD: I think the sort of filtered vent 25 25 that they're putting on is cosmetic.
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MR. SIESS: What about the French?
2 MR. WARD: It's even worse.
3 3 MR. COSTELLO: I guess I would have to say 4
4 thut ;;.en it comes down to it, I think I said this seven or 5 5 eight years ago in perhaps a different room and a different 6 6 hotel in Albuquerque, the ultimate user of calculational 7 7 techniques will be utilities or (inaudible) doing something 8 8 for the utilities to look at that utility's containment.
9 9 The insight that should come from the test and the 10 17-) understanding that comes from the test, is something the NRC U
11 11 could use themselves. But the next step, to take something 12 12 and do something for a given containment, requires an 13 13 investment and the talents of people that can do it. AGES
)
14 are quite capable of (inaudible) steel containments.
14g l 15 15 MR. SIESS: I wish you had that much 16 16 confidence that you know all -- that they're going to find 17 17 all those little places where the stress concuntration is 18 18 high.
19 19 MR. COSTELLO: Well, I think (inaudible). We 20 20 could (inaudible) past in Sequoyah and came away feeling 21 21 pretty good.
22 22 MR. SIESS: What did you learn in Sequoyah?
23 23 MR. COSTELLO: Okay. Do you want to give me 24 24 two minutes?
25 25 MR. SIESS: Just tell me the answer.
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I've got a report somewhere that we've got three 3 2 estimates, four estimates that were made by different people 3 3 about ten years ago --
4
~4 MR. COSTELLO: Ranging from from 10 psi to 5 5 100.
6 6 MR, SIESS: No, this is the one that came 7 7 before out Subcommittee, and we weeded them down to some 8 8 reasonable numbers. Ames did some and somebody else. And 9 9 we wrote a letter on it suggesting what we thought was a if-}
v 10 reasonable capacity. And I would just like to compare that 11 with what you've got.
- 11 12 12 MR. CLAUSS
- I'm not going to give you a 13 13 capacity because it's an uncertain number. I will give you
.14e'y 14 a range. The range is anywhere from 60, which is your V
15 15 downyield pressure. And I'm sure you've seen it. But I 16 16 would say that is the lower bound. And the upper bound is 17 17 probably somewhere in the neighborhood of 80.
18 18 MR. SIESS: 60 to 80.
(
, 19 19 MR. CLAUSS: 80 corresponds to about 4 20 20 percent of (inaudible). There's a lot of things that can 21 21 happen between 60 and 80, though. You also have an 22 22 anchorage to come into play at (inaudible).
23 23 MR. SIESS: How does it fail?
24 24 MR. CLAUSS: Again, there is at least three 25 25 significant possibilities along that pressure. There is O -
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general shell failure. You have equipment naturally, that
,3 2 you do over in that range. And (inaudible) the increase.
3 3 MR. SIESS: Do you have one like they had out 4
4 in the canyon?
5 5 MR. CLAUSS: Certainly.
6 6 MR. SIESS: At what pressure?
7 7 MR. CLAUSS: Between 60 and 80.
8 8 MR. SIESS: Between 60 and 80.
9 9 MR. BENDER: Is this information you're 10 10 ^y talking about what you've learned by interpreting your i
11 11 (inaudible) or what you learned by looking at the '
12 12 containment?
13 13 MR. CLAUSS: Well, both. Let me first say 14 14 that after we have our break, I'm going back to really 15 15 barely scratch the surface of what we would like to do 16 16 (inaudible). What we plan to do is analyze Sequoyah for 17 17 three different load scenarios, the one we started on is 18 - 18 going to be temperature and pressure. We're doing that one
( )
19' 19 as a bench mark and a reference (inaudible) to that were 20 20 done. We also are going to use that as a test case for 21 21 plant analysis with thermal loads.
22 22 MR. BENDER: But (inaudible) stop. That's 23 23 what I want to know.
24 24 MR. CLAUSS: Okay. Well, very simply, first 25 25 of all, we've learned something about modeling techniq is
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1 for steel containments. We think we have a pretty good feel 3 2 for what details are important in cause of strain 3 3 concentrations. And we've used that to identify those areas 4 that we feel are important, which penetrations and which 4
5 5 (inaudible) and those are the ones we select for analysis 6 6 rather than trying to analyze the entire containment, which 7 7 is (inaudible). So that's one thing we've learned; modeling 8 8 techniques and what's important.
9 9 Another thing we've learned is some idea as far as 10 what failure criteria might be good. And that allows you to 10 T D 11 11 kind of weigh the different failures, pressures that you 12 12 calculate. For instance, I have very high confidence that 13 13 the containment will at least get to the yield pressure, 14 14 which is 60. So I would say (inaudible), even though the
}
15 15 (inaudible) is very low, (inaudible) 1 percent.
16 16 Now, I also learned something, as far as what the 17 17 average number (inaudible). And that's more two and a half
- 18. 18 to three that much higher to correspond to that.
19 19 Similarly, I can go up to higher and higher 20 20 pressures. I have essentially (inaudible).
21 21 MR. SIESS: What would you estimate the 22 22 (inaudible) for what (inaudible).
23 23 MR. CLAUSS: I honestly can't tell you off 24 24 the top of my head.
25 25 MR. SIESS: The general yield would be I
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1 higher.
B 2 MR. CLAUSS: Much higher.
3 3 MR. SIESS: But the stress concentration in 4 4 the lower part where it's the same thickness would be 5 5 higher.
6 6 MR. CLAUSS: The lower half of the 7 7 containment doesn't (inaudible) below by elevations of 8 8 120 feet.
9 9 MR. SIESS: That's for Sequoyah. Now, the 1Q g 10 Watts Bar has got the same thickness all the way up and Y) 11 11 what's one for the (inaudible) concentrations start. A 12 12 general view of the Watts Bar should be considerably higher 13 13 than Sequoyah.
14 14 The same thickness all the way up. Right.
l15 15 MR. CLAUSS: Yes.
l
, 16 16 MR. SIESS: Maybe twice as high, 50 percent 17 17 higher?
l Ig 3 18 MR. CLAUSS: 50 percent higher, probably.
19" 19 MR. SIESS: And I'll put the stress 20 20 concentration in. Would that be --
l21 21 MR. CLAUSS: You know, I can make it --
(
22 22 MR. COSTELLO: I think one of things you l23 23 learn from the steel containment test was not to speculate i24 24 without seeing the details.
'25 25 MR. SIESS: Let's put the same details in O _ __ ___
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I this Watts Bar as you've done in Sequoyah, but just keep the 2
thickness the same.
3 3 MR. COSTELLO: If they were there.
4 4 Hypothesize the same details are in.
5 5 MR. CLAUSS: Well, first of all, all I'm 6 6 giving you right now is generalizations (inaudible) that we 7 7 haven't gotten to the point where we've included the 8 8 penetrations that we feel are important. But I can't tell 9 9 you what the specific strain concentrations are in Sequoyah 10 w 10 at this point.
L) 11 11 But when I give a number like two and a 12 12 half percent, that's just a broad generalization based on 13 13 the scale model test. I believe that probably our 14 14 (inaudible) to 9 or 10 percent, which I believe is probably 15 15 the level at which you really will fail, 10 percent strain.
16 16 MR. BENDER: Do you have the evaluation 17 17 approach written down somewhere?
18 s 18 MR. CLAUSS: No. What do you mean exactly?
')
19'" 19 MR. BENDER: -- sort of a discussion on how 20 20 you are going to do the evaluation (inaudible).
21 21 MR. SIESS: We're going to have to adjourn 22 22 this meeting. People have to leave. And I think we've gone 23 23 far enough to lay the groundwork for another very 24 24 interesting meeting. Once -- I think the Sequoyah Watts Bar 25 25 or whatever Dave is working on would be an excellent thing i
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1 to discuss at some future time along with some of these 2
other things. And I'm certainly open to be convinced. I 3 3 would like to be.
4 4 And I think that if we have another meeting, we'll 5 5 try to have it in Washington and we'll get some more 6 6 regulatory people.
1 7 7 MR. COSTELLO: That would be a most enjoyable 8 8 enterprise, yes.
9 9 10 l1 (The meeting was adjourned at 5:45 p.m. )
11 11
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1 mDNNww REPORTING SERVlOE a reconi of excellence
CERTI FICATE 3
3 THE STATE OF TEXAS )
4 4 COUNTY OF TRAVIS )
5 5 6 6 I, THE UNDERSIGNED NOTARY PUBLIC in and for the 7 7 State of Texas do hereby certify that the above- .
l 8
8 mentioned matter occurred as hereinbefore set out.
9 9 10 10; I FURTHER CERTIFY THAT the proceedings of such ;
V ,
11 l' were reported by me, later reduced to typewritten form under l 12 12 my supervision and control and that the foregoing pages are l l
13 13 a full, true, and correct transcription of my original 14f3 14 notes.
U 15 15 16 16 GIVEN UNDER MY HAND and the Official Seal of my 17 17 office at Austin, Texas, this 25th day of January, 1988.
18 , 18
! )
19 19 20 20 '/W! ,
<M_*
^
WILLIAM C. BEARDMORE 21 21 Notary Public in and for the State of Texas 22 22 23 23 CSR No. 919.
24 24 25 25 My Commission expires 7-1-89.
1 l
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