ML19330B008

Transcript of ACRS 243rd Meeting on 800710 in Washington,Dc. Pp 247-322.Viewgraphs Encl

ML19330B008
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Issue date:	07/10/1980
From:	Advisory Committee on Reactor Safeguards
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ACRS-T, NUDOCS 8007300026
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s 8l' 55 243rd MEETING J

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Nuclear Regulatory Commission E

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Thursday, July 10, 1980 13 5

E 14 l The 243rd Ideeting of the Advisory Committee was

s Convened, pursuant to nCtice, at 8: 30 a.m.

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'A MILTON S.

PLESSET, Chairman g

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CARSON MARK, Vice-Chairman b

18 OND F. FMY, Designated Federal Employee

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JEREMIAH J.

RAY 39 j

DAVID OKRENT HAROLD W.

LEWIS o

I JESSE C. EBERSOLE WILLIAM M. MATHIS 21 MAX W. CARBON

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WILLIAM KERR 22

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l DADE W. MOELLER MYER BENDER 23 52EPHEN LAWROSKI l

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i ALDERSON REPORTING COMP ANY. INC.

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1 MR. MILLS:

The other point of concern on the 2

Brunswick event was that the reactor was fired up with the 3

scan discharge volume vent and drain valves closed due to 4

unavailability of repair parts.

The vent and drain valves 5

are normally open and should be open.

6 MR. CARBONat Was that a tech spec violation?

7 MR. MILLS:

It was not at the time.

8 MR. CARBON 4 It is now.

9 MR. MILLSs Tech specs went out I believe just 10 recently, yesterday or today.

11 MB. NOVAK Periodically you are required to test 12 the closure time and it must close after an event.

Because 13 the closure time was slower than the tech spec requirement

~/

14 they decided, well, if you have the valve closed cert *ainly 15 that is closing very fast, but it didn't open and rer.ained 16 closed.

That was the problem we had, the fact'that the 17 drain valve was closed.

If you couple the fact that your 18 level instruments were questionable then the concern of 19 filling up that system prompted, I think, the bulletin and 20 truly the answer to Dr. Carbon's question.

It was a 21 coupling of the two.

There was a coupling there and i think 22 that is what pushed the concern out and it was a valid 23 concern.

(')

24 MR. EBERSOLE:

You are telling me they operated 25 with the vent valves closed, correct?

OG ALDERSON REPORTING COMPANY, INC.

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1 MR. MILLS:

Right.

I' 2

MR. EBERSOLEs Now, did it successfully scran with

~s 3

the reactor vent valves already closed and not closed on (d

4 delay function?

Did it ever operate properly in that mcde?

5 MR. MILLS:

Yes.

What happened in the Brunswick 6

event was they had the vent and drain valves closed.

7 MR. EBERSOLE:

Yes.

8 MR. MILLS They were using the alarm and the rod 9

block switches as a guide to when to drain the instrurent 10 volume.

They didn't get any alarms and then they finally 11 scrimmed by high level in the scram d isch a rg e volume.

12 MR. EBERSOLEs And it scrammed successfully?

13 MR. MILLS:

Yes.

(s 14 MR. EBERSOLE:

Which indicated it was all right to 15 operate with the vent valves closed, right?

16 MR. MILLS 4 In that cace, yes.

I'7 MR. SEISSs Wait, no.

It was all right to operate 18 with the water no higher than that top gauge.

19 MR. MILLS:

The scram worked properly in that 20 event.

21 MR. JORDAN:

Could we clear the record on that.

22 It was all right in that the rods were still scramnable and 23 it was demonstrated they vi4 scram, but it is not all right i

(",s) 24 to operate with that "Aa-

lv e closed, definitely no t all 25 right.

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1 MR. NOVAK:

One final comment.

When we observed 2

t.lat we did ask every operating BWR what was the status of 3

their vent line and drain line and they were all open at the g-(s 4

time.

5 MR. MILLS 4 When we reviewed that event it did 6

show the lack of tech specs in that area.

There were no 7

tech specs, for example, to require operable vent discharge 8

volume vent and drain valves.

Even on the closing time, the 9

only oae I am aware of is a closing time for an isolation 10 function, but as far as the scram function there was no tech 11 spec.

12 So required operable scram discharge volume vent 13 and drain valves required the valves to be open during 14 normal operation and a periodic testing of the valves.

15 3perable rod block and alarn switches were 16 required to provide the maximum inrormation to the operator l'7 on the condition of instrument volume.

Those were required 18 to be periodically tested.

19 Also the bulletin will provide failure data en 20 this problem to view the potential for a common cause 21 failure of water level and other common problems.

22 MR. KERR:

Why does one need to require that the 23 alarm and rod block switches be operable?

()

24 MR. MILLS:

The thought there was to provide the 25 '

operator with the maximum amount of information that is fi J

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1 available or that could be made available to him.

They pont 2

out in the tech spec the alarm switch was not included in r-3 the tech spec.

V) 4 Our findings to date with regard to the bulletin, 5

the immediate survey showed no plans for operating with the 6

vent and drain valves closed.

They were all open.

7 The 45-day reports are due July 27th so we haven't 8

gotten any detailed reports yet.

However, we have had a 9

report of inoperable rod block and alarm switches at Browns 10 Ferry as a result of the investigations made down there as a 11 follow up to the June

Sth report.

12 That concludes what I had on the Hatch and 13 Brunswick.

14 Are there more questions?

15 3R. OKRET:

You seem to feel that a wa ter hammer, 16 or some kind of a two-phased system going to a one-phase l'7 system or something like that that led to severe forces on 18 the-pipe and so forth.

Have you arrived at any conclusion 19 as to why this potential is okay or how one might uncover 20 such a potential or are there any kinds of other generic 21 ramifications?

Presumably had one anticipated at some 22

-earlier. time that a water hammer could occur here and 23 incapacitate all the switches or do something else or I) 24 whatever one would have thought about it.

So I am trying to 25 ascertain what the generic ramifications of the water hammer O

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1 occurring here ar+.

2 MR. MILLS:

My th ough t is that if the vent and 3

drain valves opera te as designed the system should not 4

experience this type of water hammer event.

By requiring 5

the periodic surveillance and requiring the operability of 6

those valves that decreases the potential for a water hammer.

7 MR. LEWIS:

It is never sufficient to say that if 8

everything operates normally we are okay.

We have here 9

obviously the potential f or an event which will damage a lot 10 of rod drives.

I can't believe that the system hasn't been 11 scrubbed over the years for such potential.

That was just a 12 comment and not a question.

13 MR. EBERSOLE:

Will you throw up the diagram again N'

14 so I can make another comment.

15 MR. MILLS:

I would make one comment on your 16 comment.

I have had discussions with the General Electric 17 Company and they have indicated that they see no potential 18 for a water hammer at all in that system.

19 MR. OKRENT:

Have you explained the scurce of the 20 forces'that bent the piping?

21 MR. MILLS:

General Electric Company?

22

!R. OKENI:

Yes.

23 MR. MILLS:

No, we haven't really gotten to that

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point, to that kind of detail yet in our follow up on this.

24 25 MR. SEISS:

Why is that a detail?

Ihe pipin; is O

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1 bent.

You said it is a wtter hammer and GE says it can't be 2

a water hammer.

That sounds fairly fundamental to me.

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3 MR. PLESSET:

Let me suggest that it may be a 4

little premature or the wrong time to pursue this and I 5

think we will come back to it.

6 MR. SEISS:

I don' t think the staff is pursuing 7

the right question.

8 MR. PLESSET:

'd ell, that may very well be.

9

53. SEISS:

At Brunswick how long did it take for 10 the water level in the instrument volume to reach the 11 high-high scram level?

In other words, how long elapsed 12 between the time they closed the drain valve and the time it 13 scrammed on high-high?

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14 MR. MILLS:

I don't know the exact time.

I knov 15 they started up on November 10th and received the scram on 16 the 11th.

I'7 MR. SEISS:

Have you any idea how much longer it 18 would have taken for the water level to rise to a point 19 where it would not have sc ra mm ed ?

20 MR. MILL 5s I can't really make an estimate on 21 that because I don ' t know.

22 MR. SIESS:

Is it days?

TP-relative volumes, how 23 much volume is relative?

e(m) 24 MR. MILLSs The instrument volume is significantly ss 25 smaller than the scram discharge volume.

The instrument O

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1 volume goes about i hundred gallons and the scram discharge 2

volume is on the order of seven hundred.

3 MR. SIESS:

You need all of the 700, do you?

4 MR. MILLS:

No.

You only need on the order of 5

about 150 at that point.

6 MR. SIESS:

So it might have been five or six more 7

days or something like that?

8 MR. LEWIS:

Well, it might have been one day 9

because we don't know where the high-high is.

10 MR. SIESS:

The water was presumably due to 11 leakage coming through the scram valves and that could have 12 changed.

13 MR. PLESSET:

Well, I am proposing that we have O

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14 another discussion of this when the staf f has had a litrie 15 more time to be a little clearer in their own minds as to 16 what went on.

I think that would help.

Otherwise we are l'7 spinning our wheels a lot.

18 Very short, Jessie.

19 MR. EBERSOLE:

Yes, I want to add some substance 20 to what might be a discussion.

In view of this horrible 21 design with its commonality will the staff give some 22 consideration of putting an excess pressure relief in that 23

_ piece of pipe between the rod drive exhaust and the fire:

(A,)

24 pneumatic operated valve, that short piece right between --

25 no,.no, the other side, th e re

--a t each rod drive put an O

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- (3) 1 excess pressure release and thereby destroy the commonality 2

of the dump function.

That would dump to the containment.

3 Then if the system didn't work properly it would be a proper 4

punitive consequence to go out and clean up the container.

5 M2. MILLSs I am sure design changes of various 6

types will be considered on this system especially as a 7

result of the Browns Ferry event.

8 If there are no more questions on the Hatch and 9

Brunswick event then I will move on to the Browns Ferry 10 event of June 28th.

11 At approximately 1:30 in the morning the opera tive 12 manual scram unit lost 30 percent power for a shutdown to 13 the fail feedwater leak.

All the rods on the west side were 14 fully inserted.

On the east side 13 rods traveled full 15 length and five were already inserted for a total of 18 rods.

16 fully inserted on the ease side.

Se v en ty -s ix rods remained l'7 partially inserted after the first scram.

18 The operator reset the reactor protection system, 19 allowed for a short draining time in the scram discharge 20 volume and initiated another manual scram.

This time rods 21 on the east side moved approximately 12 inches further into 22 the core and 34 rods were fully inserted.

23 They reset the reactor protection systen again,

(')

24 had another short drain of the scram discharge volume and 25 initiated another Janual scram.

Rods on the ease moved D[u ALDERSON REPORTING COMPANY, INC.

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1 approximately seven inches further into the core.

Fifty-cix 2

rods were fully inserted at that time.

3 They then reset the reactor protection system, 4

allowed for a longer draining time of the scram discharge i

5 volume and moved the scram discharge volume switch from 6

bypass to normal and received an automatic scram because of 7

the still high scram discharge volute Then all rods on the 8

east side were fully inserted.

9 At this point here the power level on the east 10 side was minimal as observed by local power range monitor 11 readings.

12 This shows how the control rod drives are 13 dispersed throughout the core electrically by groups for 9

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14 different electrical groups.

There was no electrical 15 malfunction determined that could cause an east only scram.

16 An electrical malfunction would result in rods being 17 dispersed throughout the core that were not fully inserted.

1r This is a functional diagram of the reactor 19 protection system.

This point here is just that all four 20 rod groups are contained in each reactor protection system 21 channel.

Cannel "A"

contains all four rod groups and 22 channel "B"

contains all four rod groups.

Both channels 23 have to be de-energized in order to get a reactor scran.

Sc

()

24 again the rods would be expected to be dispersed throughout 25 the core for an electrical malfunction.

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( 1 The rods are, however, connected hydraulically 2 through the scram discharge volume. The rods on the east 3 side of the core exhaust to the east scram discharge volume -sb 4 and the rods on the west side exhaust to the west scram 5 discharge volume. 6 Evidence to da te indica tes tha t the most likely 7 cause of the Browns Ferry event was water in the e'ast scram 8 discharge volume. While the exact cause of the water is not 9 definite a test has been run by TVA which demonstrstes that 10 if the vent is inoperable water will be help in the scram 11 discharge volume and drain _ng will not be complete. 12 The two moct likely causes, the reasons for the 13 water in the east aeader ar,e an inoperable vent line or ( 14 valve for blockaging the system. 15 MR. LAWROSKI What are the distances, the real 16 distances? 17 MR. MILLS: To the east head it is approximately 18 150 feet of 2-inch pipe. 19 MR. EBERSOLE: Are those discharge volumes 20 horizontal pipes? 21 MR. MILLS: Yes. 22 MR. EBER50LE: So there is no real head-in them? 23 MR. MILLS: This is a horizontal pipe which sits () 24 up approximately 25 feet above the instrument volume. 25 MR. EBERSOLE: Are they treated ac two independent h-ALDERSON REPORTING COMPANY, INC. 400 VIRGINIA AVE, S.W., WASHINGTON, D.C. 20024 (202) 554-2345 i

257 () 1 volumes or one total volume? 2 MR. MILLS: Treated in what sense? 3 MR. EBERSOLE: With monitoring equipment and vents 4 and drains -- well, no, you have a common drain. What about 5 vents? 6 MR. MILLSs They have a common drain. Each side 7 has its own vent. 8 HR. EBERSOLEs Only one vent on each side? 9 MR. MILLS: There is one vent on each side. Let 10 me put up a little more detailed drawing. There are 11 multiple headers. There is one vent on each side but it is 12 headed for each of the six-inch pipes here. There is l 13 commonality through the instrument volume. 14 MR. OKRENT: These six-inch pipes are ' vertical 15 pipes or horizontal? 16 MR. MILLSs Ihis is E. horizontal pipe. There is a 17 slight draining slope on it. 18 MR. LEWIS: I am a little confused by the count 19 because on one of the diagrams it says typical of six. Am I 20 not looking at the scram discharge volume on that diagram. 21 That is Figure 7-1-6 in your handout, the third page of your 22 handout. 23 MR. MILLS: Where it is on the level switch en the ,. () 24 instrument volume? 25 MR. LEWIS: Oh, there are six level switches. O ALDERSON REPORTING COMPANY, INC. 400 VIRGINIA AVE, S.W., WASHINGTON. D.C. 2J024 (202) 554-2345

258 rv~ rm() 1 Thank you. Got you. 2 MR. MILLS. Investigation into the cause of the 3 event at Browns Ferry including a complete hydraulic control 3 %_/ 4 valve alignment. All the valves on the hydraulic system on 5 the control rod drive were vertified to be in a correct 6 po si tio n. Short af ter the event, I think th a t was completed 7 that morning by 5 o' clock. The east main vent valve was 8 verified to be operable. 9 The only anomaly found with the vent at the time 10 was after the vent valve was found to be operable and wa s 11 disassembled. A vacuum pump was hooked up to draw a vacuum 12 in the vent line and it proceeded to vent better, in other 13 words, away from the scram discharge volume. A vacuum was b L-14 observed of about nine inches of mercury and then it dropped 15 off to appro ximately two inches, which was really to zero on 16 the scale. So there wss about seven inches of mercury 17 vacuum. No debris could be found after that test and there 18 is no conclusis evidence found as a result of that test. 19 Thirty-five rods were friction tested almost 20 immediately. The calibration was begun for the 3, 25 and 50 . 21 gallon level switches. The 3 to 25 were found to be sticky 22 and operated after being tapped. All the scram switches 23 were operable. Radiation surveys were done. Ihe drain cump () 24 was sampled. The reactor coolant was sampled. All cas l 25 radiation levels simpled. No anomolies were found. There GV '. ALDERSON REPORTING COMPANY, INC. 400 VIRGINIA AVE, S.W., WASHINGTON. D.C. 20024 (202)554 2345 .-. l

259 (} 1 were visual and mechanical inspections of the vents and 2 drains on the scram discharge volume. It showed no 3 anomolies. No maintenance or modification had been g 4 performed that could affect the control rod drives. The 5 scram history was reviewed for any previous occurences. No 6 relevant occurrences were found. Various tests were 7 performed and a flow and draining of the scram discharge 8 volume. 9 Evaluations and inspections were performed to 10 assure electrical separation and diversity. The General 11 Electric Company performed extensive evaluations and j l 12 inspections. Scram actuators were tested to ensure that 13 they de-energized properly. The two-inch drain line that we + 14 saw before, the 150 feet line was cut at several places and 15 inspected. No blockage was foun. in tha t line. The scram 16 discharge instrument volume was inspected with a Boroscope. 1 17 No debris was found in there. The drain tank was inspected 18,and nothing was found there either. 19 The potential of electric malfunctions to be the 20 cause was evaluated. Response times for de-energizing the 21 scram polots were 'ound acceptable. The scram groups were 22 found to be as we discussed before, not separsted east and 23 - west but' dispersed around the core. Srram valves for each () 24 control rod as operated as verified by blue lights indicated 25 in the control room, the operator got the blue lights which O ALDERSON REPORTING COMPANY, INC. 402 VIRGINIA AVE. S.W., WASHINGTON, D.C. 20024 (202)554-2345

r;- - 260 () I come off of limit switches and the scram valves, the inlet 2 and the exhause valve, which indicated that those valves had e1 -3 opened and th a t the electrical function had been completed. ( 4 Immediate inspection of the scram group fuse cabinets was 5 completed. That is a point of commonality which could be 6 postulated that the power supply could be inadvertently ~ 7 connected. Nothing was found there. No adnormality. 8 Based on this the logical conclusion is that 9 electrical malfunctions could not have created the West only 10 scram. 11 Unit 3 is undergoing extensive testing of the 12 scram discharge volume in the control rod drive system and 13 the drive performance. Verification testing, first of all, 1-4 in the UT method to determine if there is water in the scram 15 discharge volume independently of the level switches. The 16 vacuum hose test showed that if the vent path were blocked l'7 that the vent valve would close and water would be held up i 18 a nd drainir.7 would not be complete. The dcain test 19 demonstrated that it would drain properly if the system were 20 in normal alignment. Friction tests had been completed en 21 the drive. No abnormalities have been found. The screa 22 testing under various conditions will be pe rf o rme d for each 23 of the drives on the east side. (m) r 24 MR. PLESSET: How much longer do you need? 25 MR. MILLS: I only have two more slides after this. O \\s ALDERSON REPORTING COMPANY, INC. 400 VIRGINIA AVE, S.W., v. ASHINGTON, D.C. 20024 (202)554-2345

261 'f) 1 MR. PLESSETs Can you make it real short? a 2 MR. MILLS: Yes. Browns Ferry has implemented a 3 UT check in the scram discharge volume piping to inspect for O 4 water following each scram. The shift crews have been 5-inspected on how to respond to an event of the type that 6 occurred th e r e. They have increased their carveillance of 7 the scram discharge volume level switches. They have 8 checked the valve alignment on the control rod drive system 9 once a shift. Unit 3 will remain shut down until the NRC 10 concurs in the restart. 11 MR. OKRENT: I don't understand everything and how 12 it is connected on that previous vievgraph. Could you put 13 it on for a minute? 14 If we had water which didn 't drain because the 15 vent valve was closed would you expect to find anything on 16 those float type instruments? 17 MR. MILLS: No. If the water were held up above 18 in the discharge volume then you would not expect to see any. -19 MR. OKRENT: Now, could you have water in that 20 discharge volu 7 if the scram had not occurred due to 21 leskage, for example? Could it be held up having cotten in 22 with the vent valve not functioning properly? Is the 23 question clear? r" (,% 2 ) 24 MR. MILLS: Water couldn't have gotten in there 1 25 from leakage. If the vent valve weren't functioning O ALDERSON REPORTING COMPANY. INC. 400 VIRGINIA AVE, S.W., WASHINGTON, D.C. 20024 (202)554 2345

262 f])' 1 properly from the last scram water could have remained in 2 there and not drained out from the previous scram. 3 MR. OKRENT4 No. 1 item says UT check of scram 4 discharge volume piping for water after each s c ra n.. My 5 question is can we not get water in for that scram discharge 6 volume without a scram and could it be held up? 7 MR. MILLS. The sources of water would be, for 8 example, the leakage through the vent exhaust valve which I 9 mentioned. That one would not be expected to be held up 10 because of the level and the leakage rate would be very lov 11 and should trickle through the system. Another source of 12 water could possibly be back up through th e ven t. If closed system and it was siphoning 13 somehow you were in = (~% k/ 14 water back through the vent water could enter that way. 15 Another source of water would be back up through the drain 16 and that one you would expect to detect from the level 17 switches. The only other source of water I can think of 18 would be the flush lines that are connected onto the header. 19 MR. EBERSOLEs. What do you mean by item two? 20 MR. XILLS: In essence they have been instructions 21 on how to respond if they had to 22 MR. EBERSOLEa Does that include instruction to 23 avoid wash out of boron? (). 24 MR. MILLS That specific question I can't answer 25 from the procedures. ] ALDERSON REPORTING COMPANY, INC. 400 VIRGINIA AVE, S.W., WASHINGTON, 0.0. 20024 (202)554 2345

263 () 1 MR. EBERSOLE: It is impo rtant. I' MR. MILLS: My understanding is that that has been 2 3 definitely considered, and if they haven't overreaction to 4 this event it wouldn ' t initiate standby liquid control 5 prematurely. 6 MR. EBERSOLE: By having done so they would keep 7 it in the reactor. 8 MR. LEWISs I am a slow learner. Could you remind 9 me why setting the scram discharge volume to normal fixed 10 everything. I lost track. What does that do. 11 MR. MILLS: What I meant to say at that point was 12 that' moving the scram discharge volume switch and causing 13 automatic scram in no way is viewed to play the part 14 different than a manual scram. It really was just another 15 scram. The part that is probably more significant is that 16 you waited for the scram discharge volume to drain longer 17 because drain time before that scram was over four minutes. 18 After previous ones it was like 53 seconds, a minute and 19 half and things of those types. 20 MR. KERR: I was curious because the times ycu had 21 listed indicated six minutes between scrams. What do those 22 times mean then? 23 MR. MILLS: The six minutes is the time between () 24 manual scrams. In order to drain you have to reset the 25 scram that is already in there. In the six minutes you \\ l ALDERSON REPORTING COMPANY, INC. 400 VIRGINIA AVE, S.W., WASHINGTON, D.C. 20024 (202) 554-2345

r. w-261 () 1 resets the scram and then the scram instrument volume drain 2 and vent valves open and you can drain that system, but you 3 can't drain the system until the scram is reset. Ihen the 4 other times shown is when you initiated the second manual 5 scram. The total time between scrams is made up of a reset 6 time plus a draining time. The total time was six minutes, 7 let's say, in the first case. Of that six minutes four and 8 a half minutes were prior to the reset and a minute and a 9 half were af ter af ter the reset when the draining function 10 could be effective. 11 MR. KERRs Thank you. 12 MR. LEWIS: Still, you know, I am a slow learner. 13 What does normal mean for the scram discharge volume switch? A\\l 14 MR. ILLS: When you get a reactor scram it fills 15 up. Normal means that that scram function is in effect. In 16 order to reset the scram you have to bypass that scram. So l'7 the operator takes that switch and goes from normal to 18 bypass and the bypasses the scram and the scram discharce 19 volume high level. 20 MR. LEWIS: Ihen it says he resets it to normal. 21 I as trying to understand. I am just being igno ran t. 22 MR. MILLS: After he had given it a four-minute 23 drain time he, and I as guessing, maybe he thought it was () 24 already drained so he went from normal to bypass. In any 25 event, that is what he did. He just took tha t switch from O. ALDERSON REPORTING COMPANY, INC. 400 VIRGINIA AVE. S.W., WASHINGTON, D.C. 20024 (202)554-2345

265 () 1 normal and put it into bypass which then put that scram 2 signal back into effect. 3 MR. LEWIS You said he turned the switch from -%U 4 normal to bypass. I think you meant to say bypass to normal. 5 MR. PLESSET: I know the members want to clear 6 things up instantly. I am going to propose that we come 7 back to this later on. We will have one of our ACPS fellows 8 describe to us at an early date in terms that I think we 9 will understand. So if you don't mind we will terminate 10 this presentation.- 11

53. OKRENT:

I only have one question. Did we 12 hear what it was that p reven ted the rods from going in the 13 first time? Did you tell us? 14 MR. MILLS Evidence points to water in the east 15 header of the scram discharge volume. 16 MR. OKRENT: You didn't tell us why that water was 17 held up ~there, did you? 18 MR. MILLS: The reason why it is h eld up has not 19 been shown definitely. 20 MR. LEWISs Did you overstate the case that 21 evidence indicates that or that lack of any other cause 22 suggests that? 23 MR. PLESSET: Well, let me again say that I tnink (O ,/ 24 we will come back to this. We are going to really dig into 25 it. It is not a trivial matter and wc all very much O ALDERSON REPORTING COMPANY, INC. 400 VIRGINIA AVE. S.W. WASHINGTON, D.C. 20024 (202)554-2345

26G () 1 concerned. We are going to have a rather lucid presentation 2 I promise. 3 MR. LEWIS: Tomorrow. 4 MR. PLESSET No, not tomorrow, at the next 5 meeting. Let me go now, if that is agreeable, because I 6 think otherwise you are going to get very poor return on 7 your mining efforts. 8 SPEAKER: And a long night. 9 MR. PLESSET: Yes, and a long night. We are not 10 at all losing one whit of our concern in this whole matter, 11 but we do want to understand it thoroughly. 12 Mr. Gridley of GE wants five minutes, and it is 13 five minutes and not six. So will you come forward. 14 MR. GRIDLEY: My name is Dicx Gridley. I am 15 Manager of Fuel and Licensing Services for the General 16 Electric Nuclear Energy Business Group. I'7 I would like to summarize the actions which OE has 18 taken with the TVA people to help determine the cause of the 19 scram incident at Browns Ferry on June 28th and to describe 20 our actions to prevent future occurrences. 21 I will cut my remarks and be as brief as I can - 22 recognizing the time and certainly would be very interested 23 in coming back again at the next meeting. Sill Mills has () 24 describe quite well the facts that we learned at the site. 25 I would like to just state that TVA notified Genetal O ALDERSON REPORTING COMPANY,.

• 400 VIRGINIA AVE, S.W., WASHINGTON, D.C. 20014 (202)554-2345

267 ~ / 'i 1 Electric of the partial insertion of the east bank rods the \\/- 2 same day th a t it occurred. The GE operations engineer was 3 already on site and we had direct telephone conversations 4 and consultation underway that day. 5 Following the notification of TVA on the 29 th GE 6 set up and initiated in fact direct telephone consultation 7 with the site. In addition, we established a management and 8 engineering task force in San Jose and at the Browns Ferry 9 site to assist TVA in the evaluations and the tests and the 10 analysis that followed. J 11 - I was going to describe some detail as to GE's and 12 TVA's efforts in determining the cause but Bill has quite 13 readily concluded that the mechanism of the scram failure i 14 was water in the discharge volume. Why the water was there 15 we still have not placed a firm convincing handle on it. We 16 know that the most likely cause was either the vent system I'7 or blockage er restriction in that long two-inch header. 18 As a result of our evaluations guidelines were 19 sent to eacn operating utility on July 7th which reinforced 20 existing procedures to the vperators should such an incident 21 occur at their plan t in the future. 22 We have also recommended interim Ur monitoring i 23 techniques as a more positive means of verifying absence in () 24 the scram discharge volume. Also we are checking to be sure 25 that the instrumentation associated with the system does [m ALDERSON REPORTING COMPANY, INC. 400 VIRGINIA AVE, S.W., WASHINGTON. D.C. 20024 (202)554-2345

268 (~T 1 function properly. V 2 We believe th a t the monitoring techniquec and the 3 operator guidelines are adequate to ensure that the incident O 4 does not occur in the near future. We base this confidence 5 on the fact that we have had over 300 reactor years of 6 operating experience with complete scrams during that period. 7 The cesults of thousands of scrams at San Jose 8 test facility also gives us confidence that there are no 9 fundamental problems with the basic design of the control 10 rod drive system itself. 11 I would like to just take one more minute and. 12 summarize what we see in the future. We are currently 13 working on a design of the system for a continuous 3 (s) 1-4 monitoring of that scram discharge volume. This system will 15 provide an alarm which will signal the need for operator 16 action if the level reaches a predetermined value. I'7 Currently we are considering either an ultrasonic 18 or a conductivity probe as an installed sensor in this scra.m 19 discharge volume. 20 In addition, GE is evaluating the design 21 requirements for venting 3.id draining of the volume. We 22 expect to have recommendations for our customers in a timely 23 manner. () 24 With that brief statement I will stop and'take any 25 questions if we have time. (~' t ALDERSON REPORTING COMPANY, INC. 400 VIRGINIA AVE S.W., WASHINGTON, D.C. 20024 (202) 554-2345

269 () 1 MR. PLESSET: Let's just take a few. -2 MR. MARK 4 Have you tried in some test facility to 3 see if putting a monitor in that long place you can get 4 similar effects as this? 5 MR. GRIDLEY: Yes, we have. We conducted in 6 control rod drive test facility in San Jose in a 7 configuration that similated Browns Ferry scrammino a 8 production drive with varying volumes and we got exactly the 9 same condition. 10 ER. BENDER: What is meant by the operator action 11 following the sonic signal? 12 MR. GRIDLEY: We are trying to determine by that 13 method whether there is water present in the scram discharge 14 volume. If there is water in that volume then, you know, he 15 needs to take action to shut the plant down. I might sdd 16 that in scramming versus, you know, controlled shutdown, the 17 impact on the system is completely different. 18 MR. BENDER: The term " shut the plant down" 19 doesn't convey gutte the message I wanted. 20 MR. GRIDLEY: I guess maybe I need some help on 21 this. The procedure that we have indicated for the operator 22 to evaluate is if he has presence of water in the scra.- 23 discharge volume he would immediately start inserting rods, () 24 but I think now I am on shaky grounds because I am not sure 25 that we have looked at the procedure other than following O ALDERSON REPORTING COMPANY, INC. 400 VIRGINIA AVE, S.W., WASHINGTON, D.C. 20024 (202) 554-2345

270 r> () 1 normal shutdown. 2 MR. BENDER: We don't need to know now. Thank you. 3 MR. OKRENT: Normal shutdown is not easy and is 4 not fast. You can do it by putting in one rod at a time and 5 so forth, but I don't know whether you have that kind of 6 time if you don't know how the water is getting in and at 7 what rate. 8 MR. GRIDLEY: That is a good question. I really 9 don't see any problem with proceeding with a normal 10 shutdown, but I think we need to evaluate that and decide i 11 whether or not there is a need for more expedient action. 12 MR. LEWIS: I can't resist a probabilistic 13 comment. Sure you want higher reliability for the scram 4 _s ) 1-4 system than you can justify on the basis of operating 15 experience so f ar. So that is no'. a good argument. 16 MR. PLESSETs It is so different f rom o ther l'7 numbers we have heard in the past, but we don't need to 18 belabor the point. I think it is pretty clear. 19 Mr. Lellouche isn't here to revise his numberc. 20 (Laughter) 21 So thank you, Mr. Gridley. We are going to pursue 22 this and you will be in touch with us and vice versa. 23 MR. GRIDLEY: Thank you. () 24 MR. PLESSET I think that I am not going to let 4 25 you have a break until we finish the discussion of the St. ALDERSON REPORTING COMPANY, INC. 400 VIRGINIA AVE, S.W., WASHINGTON, D.C. 20024 (202) 554 2345 ?

9 7 *1 w. 1 Lucie Unit 1. 2 MR. KERR: Mr. Chairman, I don't think we should r~g 3 give the wrong impression. This reactor was shut down. (w) 4 MR. PLESSET: Oh, yes, I agree. 5 MR. KERR: When the button was pushed half the 6 rods went in. The incident is certainly serious. 7 MR. PLESSET: Yes. That is all I meant, that it 8 was a serious incident and one in which we are continuing to 9 be cJicerned and we want to understand it quite fully. 10 Let's go then to this St. Lucie Unit 1 item. 11 MR. JORDAN: Ed Blackwood is going to give you a 12 presentation on the St. Lucie event. There are other NRC 13 staff here to back up the presentation. So, Ed, why don't 14 you proceed. 15 MR. BLACKWOOD: Edward Blackwood. This is an 16 agenda of the items I would like to discuss briefly with you l'7 this afternoon. 18 First of all, site description and event 19 description we will spend probably a little bit of time on 20 and I will be ;1ad to answer any questions you nay have. 21 The areas of specific interest dealt with the reactor 22 coolant pump seal performance, steam void indications in the 23 reactor vessel head and anonalous solid plant indications. () 24 Now, following this Brian Sheron of the staff will 25 discuss the safety impact and the future actions regarding (" 's-)/. ALDERSON REPORTING COMPANY. INC. l 400 VIRGINtA AVE, S.W., WASHINGTON, D.C. 20024 (202)554-2345

272 () 1 steam voiding the reactor vessel head during na tu ral 2 circulation cool down. 3 This is self explanatory. It is a brief bw 4 description of the St. Lucie site and the type of reactor 5 and some other details. The criticality of this c: cle was 6 May 7th, 1980, and following the loss of component cooling 7 water they restarted on June 30th and achieved 100 percent 8 power on July 1st. 9 This is a summary of th e se quence of events.which 10 I believe are significant to the three areas of interest 11 which we have. 12 At time 0226 on June 11th valve 14-6, which is one i 13 of the series return valves from the component cooling water 1-4 coming back from all four reactor coolant pumps failed to 15 shut. It failed to shut as a result of a short in a 16 terminal board tha t was associated with the solenoid air 17 operated valve which in turn operates the component cooling 18 water valve. 19 This is a rather busy print but the area of 20 interest is the component cooling water which cuts in this 21 way and penetrates the containment and goes through all four 22 reactor coolant pumps which are in parallel and then a l 23 common return line coming back. Valve 1R-6 is this air ) () 24 operated valve right here, one of the two series isolation 25 valves in the return line. This the one that f all, 4 to p ALDERSON REPORTING COMPANY. INC. 400 VIRGINI/= AVE. S.W., WASHINGTON. D.C. 20024 (202) 554-2345

273 () 1 shut. The air operated solenoid valve is here and the power 2 to this valve is what failed due to a short in a terminal 3 box that was located approximately two feet away from it. } 4 After a brief attempt to restore component cooling 5 water at time 0233 the reactor was tripped manually from 94 6 percent power. Within two minutes all four reactor coolant 7 pumps were secured and a minute or so later 1-B reactor 8 coolant pump was restarted and run for approximately one 9 minute in order to enhance natural circulation. 10 At time 0300 the natural circulation cooldown was 11 commenced. 12 At time 0350 the failed component cooling water 13 valve was reopened by jumpering an airline around the 14 solenoid valve who power supply had failed. 15 The cooldown continued uneventfully until around 16 0600 or sligh tly thereafter. At 0600 they depressurized, er 17 started the depressurization from 1,140 pounds down to 690 18 pounds charging is he a ilia a 19 kr'ssurdz'r. 20 Since reactor coolant pumps were not operatina 21 there was pump induced spray because there was essentially 22 no differential pressure across the core. That is why they 23 have an auxiliary spray line. () 24 MR. LEWIS: Is it a normal procedure hy the way to 25 start a pump to enhance natural circulation and to run it O ALDERSON REPORTING COMPANY, INC. 400 VIRGINIA AVE. S.W., WASHINGTON, D.C. 20024 (202) 554-2345

27d () 1 for a minute like that? 2 MR. BLACKWOOD: I don't know. They wanted to make 3 sure they didn't set up a reverse flow. It was that type of 3 %) 4 a situation. 5 Between 0600 and 0630 they depressurized, and 6 around 0615 they noted variations in pressurizer level that 7 were a'little bit of f no rmal. 4 8 Now, between time 0630 and 1230 they alternated 9 charging to the auxiliary spray line to cool the pressurizer 10 down and allow them to depressurize and to the reactor

• 1 coolant loops the rest of the time to make up for i

12 contraction in the system due to cooldown. 13 Between 7 o' clock and 7:30 they had initial r)h ( 14 indications that there may be voiding in the reactor coolant 15 system somewhere other than the pressurizer. At this time 16 the subcooling, that is, saturation temperature for l'7 pressurizer pressure minus hot leg temperature ranged 18 'between, it sa,ys 200 here, it wa s actually between 220 19 degrees at 0600 and about 150 degrees around 0730. So at 20 all times they had adequate subcooling regarding the bulk 21 coolant that was circulating via natural circulation through 22 the core, the loops and the steam generators. 23 At time 1051 pressure and temperature were down - I') 24 far enough to start low pressure safety injection punp in L 25 the shutdown cooling mode. -s J ALDERSON REPORTING COMPANY, INC. ' 400 VIRGINIA AVE. S.W. WASHINGTON, D.C. 20024 (202) 554-2345

275 () 1 From 7:30 until right around 12:15 they 2 experienced rather large variations in pressurizer level. 3 These were not uncontrolled oscillations. They were 4 controlled by whether they chose to charge into the 5 pressurizer via the auxiliary spray line or charge to the 6 cold legs. 7 MR. OKRENT: When they started the'LPSI were they 8 adding water to the primary system? 9 MR. BLACKWOOD: No, they started it in shutdown 10 cooling. 11 MR. OKRENT: The recirculation mode? 12 MR. BLACKWOOD. The shutdown cooling mode. 13 Now, this is a good place to look at the trace of 14 pressurizer level. It is in two parts. You will notice the 15 reactor trip at time 0233. The solid line across here is 16 prog rammed pressurizer level. 17 MR. LAWROSKI Excuse me. 18 MR. BLACKWOODs Yes. 19 MR. LAWROSKI: Could you use the pointer on the 20 table there. 21 MR. BLACKWOOD: The solid line is the programmed 22 pressurizer level and, as indica ted, this is one channel of 23 the hot calibrated pressurizer level which they had selected ( J' 24 for the recorder. 25 From time 0600 to 0630 they depressurized as ) ALDERSON REPORTING COMPANY, INC. 400 VIRGINIA AVE, S.W., WASHINGTON, D.C. 20024 (202) 554 2345

?)}

t. * -

() 1 indicated, and around 7 o' clock they noted a rapidly 2 increasing pressurizer level at a much faster rate than the 3 charging rate. O-4 Now, furthat on in the morning they did a couple i 5 of tests and determined that the rise in pressurizer level 6 was approximately a factor of 10 greater than the charging 7' rate. Throughout most of the cooldown they were charging 8 with two coolant charging pumps at a rate of 88 gallons a 9 minute. 10 Around 7 o' clock to 7:30 they had pretty good 11 indications that there was a void in the system somewhere 12 other than the pressurizer. 13 There were a number of things that happened in 14 here during this dip in pressurizer level. They recovered 15 it and essentially continued the pressurizer cooldown and 16 the natural circulation cooldown. j 17 MR. EBERSOLEs This occurred after they were on 18 shutdown cooling, right? 19 MR. BLACKWOOD: No. 20 HR. EBERSOLE: Before? 21 MR. BLACKWOOD: Shutdown cooling occurs at time 22 1051. 23 MR. EBERSOLE: Got it. (m t _) 24 MR. BLACKWOOD: Right about here. s 25 MR. KERR: What was the system pressure at that ALDERSON REPORTING COMPANY, INC. 400 VIRGINIA AVE S.W., WASHINGTON, D.C. 20024 (202)554 2345

v.* 277 () 1 point? 2 MB. BLACKWOOD: At the point they went on shutdown 3 cooling? I would say 200 or 250 pounds, something like 4 that. There is an administrative requirement that it be 5 less than 300 or s90. 6 MR. M0ELLERs What was the explanation on the 7 previous chart of a drop in the pressurizer water level? 8 MR. BLACKWOOD: I will explain that. 9 Througiaut the morning during the pressurizer 10 cooldown the level did this, basically it sawtoothed. The4 11 explanation is that during the charging into the pressurizer 12 via the auxiliary spray line they saw these very rapid rises 13 in the pressurizer level and that is attributed to 14 collapsing the steam bubble in the pressurizer due to 15 charging in relatively cool water from the auxiliary spray 16 line. I'7 Now, during most of the morning letdown was 18 secured and that would have caused the chargin; water into 19 the auxiliary spray line to be roughly the same as volume 20 control tank temperature water which was I would say roughly 21 120 degrees or something like th at. So it was relatively 22 cool water. They were able to collapse the bubble in the 23 pressurizer very rapidly and the resultant insurge that () 24 caused this rise in pressurizer level was expansion of the L' 25 steam void in the reactor head. ("% ALDERSON REPORTING COMPANY, INC. 400 VIRGINTA AVE. S.W., WASHINGTON, D.C. 20024 (202) 554-2345

w-278 c.e- - cm (_) 1 Now, during the down ramps they were charging via 2 the cold legs and we don't attribute that charging to having g 3 very much to do with the decay in level. The explanation J 4 for the decay off in level is that spraying into the 5 pressurizer steam volume is really a transient effect in the 6 cooldown in the shall of the pressurizer. You don't 7 completely cool down all of the waicr in the bottom half of 8 the pressurizer either such that when they weren't spraying 9 down the steam bubble in the pressurizer was experiencing 10 some amount o,f reheat which was enough to cause it to expand 11 against the void in the reactor vessel head. As a result 12 there was an insurge back through the surge line into the 13 reactor coolant system. O 14 Down in this area the surges get pretty violent 15 and they were concerned right around noon that they may 16 reach a condition where they would have saturation in the 17 loops. They had roughly 50 degree subcooling at a littia 18 after noon, let's say, 17.s10 or something like that. They 19 were in a rather difficult position because if they charged 20 into the loops, and they had pressurizer heaters out by this 21 time. They h ad pressurizer heaters and they were trying to 22 recover the pressure. They were'at-about 110 pounds or so, 23 right around here at tine 1215 with 50 degrees subcooline. (m_) 24 As they charged into the loops they would see the 25 rapid decrease in pressurizer level which they could not {%) T ALDERSON REPORTING COVPANY, INC. 400 VIRGINIA AVE, S.W., WASHINGTON, D.C. 20024 (202)554 2345

a 279 () 1 keep up with the charging pumps. They had isolated letdown 2 and they were worried about uncovering the pressurizer 3 heaters which would not enable them to use the heaters to 4 try'to regain pressure control. 5 The only alternative was to charge via the 6 auxiliary spray line, or in this case charge for short 7 periods of time via the auxiliary spray line in order to 8 keep the pressurizer level on scale. 9 Now essentially what they were doing here was 10 maintaining the steam void in the reactor vessel in order to 11 keep the pressurizer level on scale in order to run the 12 pressurizer heaters. So it was somewhat of an untenable 13 situation. That is why at time 1226 they started the one O 14 alpha low pressure safety injection pump in the injection 15 mode takin the suction from the refueling water storage tank 16 and discharging into a common header. We will come back to 17 this one a little bit later. 18 MR. OKRENT Is there a dra wing of what the level 19 in the vessel was at this time? 20 MR. BLACKWOODs No, that is not indicated. 21 MR. MOELLER: At that time at 1226 or whateter it 22 was then the pressurizer is solid? 23 MR. BLACK'400D: Well, they thought it was solid () 24 and I am getting_ to that. 25 At time 1227 they started the pump in the ALDERSON REPORTING COMPANY, INC. 400 VIRGINIA AVE, S.W., WASHINGTON, D.C. 20024 (202) 554-2345 n

r> ' - 230 () 1 injection mode and by time 1230 the pressurize'r level trace 2 you have here is a hot calibrated level. They also have a 3 cold calibrated channel, that is calibrated at ambient gg (/ 4 te m pe ra tu res, for water in the pressurizer at ambient 5 temperatures. 6 Now, at this point water in the pressurizer was at 7 approximately 350 degrees and they did not have any sort of 8 density conversion such that they could correct that cold 9 calibrated level indica tor. Now, that level indicator went 10 - to about 64 percent and remained constant right around time 11 1230. They were charnging water at approximately SS gallons 12 a minute. The pressurizer level at hot leg was pe;ged high 13 which they expected. The cold leg was steady at 6u 14 percent. They knew that that was not an accurate reading, 15 but since it wasn't moving they thought that the pressurizer 16 at that poin t was solid. 17 Now, the anomaly here was that if the plant was 18 solid and they were charging at 88 gallons a minute they 19 should have seen a pressure increase, although they didn't 20 see a pressure increase. So this was cause for concern. 21 They investigated possible leaks. They did valve line-up 22 checks on the shutdown cooling system, the low precsure 23 safety injection system. They looked at containment levels () 24 and other auxiliary tank levels and everything trying to do 25 an inventory balance to see if they could find out where i OL.) ALDERSON REPORTING COMPANY, INC. 400 VIRGINIA AVE, S.W., WASHINGTON. D.C. 20024 (202)554 2345

281 ,~. () I this 88 gallons of water was going. 2 Now, at around 1300 they found the miniflow r' 3 isolation valve on the 1B low pressure safety injection pum p D) 4 had just cracked open. At that time that valve was shut. 5 They continued injecting from the refueling water 6 storage tank the LPSI pump 1A until time 1357 at which time 7 they noted a slight increase, the width of a pen 8 essentially, in the refueling water tank level. Now, the 9 width of a pen at 15,000 gallons a foot in the refueling 10 water tank amounts to about 5,000 gallons of water that 11 somehow or other ended up in their refueling water tank that 12 wasn't thera before. 13 So at that time they secured the 1A pump which was 14 in the injection mode. They shut the miniflow line mete r 15 operated valves and they also noted a slight rise in 16 pressurizer level and a slight rise in pressurizer 17 pressure. The pressure went from 200 pounds which it had 1 18 been pretty much constant during the injection time frane, 19 and from there it went to roughly 250 pounds. So they 20 regained some normal indication of charging at 09 ;allons a 21 minute. 22 They maintained pressurizer heaters on throu;hout 23 this time. By time 1500 they had drawn a bubble in the (_s) 24 pressurizer and driined back to the indicating range, and by 25 time 1600 they had moved back to the pressurizer level ALDERSON REPORTING COMPANY, INC. 400 VIRGINIA AVE, S.W., WASHINGTON. D.C. 20024 (202) 554-2345

r.. 282 () 1 trace. By time roughly 1600 or so with charging greater 2 than letdown in this area they had regained normal 3 indication or normal plant response for charging with two 4 pumps at a rate greater than the letdown flow. 5 Now into the areas of specific interest. Reactor 6 coolant pump seal performance is the first one I would like 7 to discuss. i 8 MR. OKRENT: Excuse me. Was the Incident Center notified of this during this time period? =_ 10 MR. BLACKWOOD: Yes. I was called at 3:15 in the 11 morning. After a couple of tailed attempts to get a 12 confernce call going I just decided to go in and I got there 13 about a quarter to four and I stayed from then through 4 in C') 14 the afternoon. So I was there pretty much the whole time. 15 Now, I think around 8:30 or so I had made all the 16 notifications. The operations center did not have knowledge l'7 of the variations in pressurizer level at that time. I left 18 instructions with the olant to call me if they had problems 19 and in any case when they got on shutdown cooling, which 20 they did. I was notified about 11:15 that they were on 21 shutdown cooling. n Now, at 11:39 after watching the pressurirer level 23 and by that time, going back to this picture, you will nets. () 24 that the swings were becoming a little bit more severe than 25 they had been earlier in the morning. At time 1139 the /^% 'N s ALDERSON REPORTING COMPANY, INC. 400 VIRGINIA AVE, S.W., WASHINGTON, D.C. 20024 (202)554-2345

283 ( 1 licensee called the operations center back and then I went 2 back in there and stayed until about 4 o' clock or so. It 3 was at time about 1139 that they called and said they 4 thought they had indications of a steam void some place 5 other than the pressurizer. It was about that time that 6 they were becoming concerned over their ability to stay 7 above loop saturation, which I have already discussed. 8 MR. MOLLER: What triggered their call to the 9 incident center? In other words, at which particular point 10 does it trigger them to call? 11 MR. BLACKWOOD: Well, the first call was pursuant 12 to 50.72 because they had an unscheduled reactor trip. 13 MR. MOLLER: Well, that was several hours before f 144 they called. 15 MR. BLACKWOOD: No, they called at time 0233 and 16 they called the operations center either a little before 3 1'7 or right araund 3. 18 MR. MOLLER: Oh, I am sorry. I was thinking it 19 occurred earlier. Well, then, what would have tri;gered you 20 to initiate action at the incident response center in terms 21 of having the chairman out and so forth? How far would thic 22 have had to have gone before that was done? 23 MR. BLACKWOOD: Ed, would you care to answer that? () 24 MR. JORDON: Certainly if those diversion 25 oscillations had continued any further that would have been O ALDERSON REPORTING COMPANY. INC. 400 VIRGINIA AVE S.W., WASHINGTON, D.C. 20024 (202) 554-2345

284 () 1 basis for activating the operations center. In terns of the 2 licensee's response, we have already conveyed to the 3 licensee his lack of advising us of this I would say 4 unstable performance in terms of the charging flow a.}d the 5 change in pressure and change in level which indicated a 6 void in the reactor vessel. That is something we should 7 have been notified of immediately. 8 MR. MOELLER: So if you had been notified of that 9 earlier you might have activated the center? 10 MR. J3RDAN: We would have been manning the center 11 during that particular phase and understanding it and been ~ 12 ready to activate. We had manned up until 8:30 or so in the 13 morning and then people went back to normal duty stationc O \\/ 1,4 with the duty officer still in the operations center. 15 I would like to make a plea at this poin t in terms 16 of the nuclear data link. This would be, I think, one of 17 the best examples we have had where the nuclear data link 18 would have provided the operations center with the right 19 information as opposed to erroneous information. 20 MR. MOELLER: Then you would have had this pict? 21 MR. JORDAN: That parameter would be plotted, yes. 22 MR. MOELLER: Thank you. 23 MR. KERR: At what point did you man the emergency () 24 response center with 50 or 60 people?- 25 MR. JORDAN: We did not activate the operations /O, Yw ~ ALDERSON REPORTING COMPANY, INC. 400 VIRGINIA AVE. S.W., WASHINGTO l. o.C. 20024 (202) 554-2345

285 ,,() f center. I will differentiate. Activate means that we have 2 called in the chairman and the directors. We manned it 3 which is a convenience for placinq proper staff there to i 4 monitor particular questions. 5 MR. KERR4 How many people were there, the duty 6 officers? 7 MR. JORDANS The manning was like three pecple. 8 MR. BLACKWOOD: It was two or three in the morning. 9 MR. KERR Had you had this information would you 10 have called in the full force at some point? 11 MR. JORDAN I don ' t believe with the occurrence 12 as it was going on had we had the information we would have 13 activated the center. We would have continued to man it. ~% 14 MR. KERRs All right. So with the nuclear data 15 link what would you have done differently than what you did? 16 MR. JORDAN 4 I believe we vould have been able to l'7 advice the licensee that he had indeed a void and to 18 repressurize. 19 MR. BLACKWOOD: I believe the licensee knew they 20 had a void but t'sy were still very concerned about the 21 integrity of the reactor coolant pump seals. They had been 22 with out cooling water for approximately an hour and a half. 23 They were ran for about eight minutes. The vendor's () 24 recommendation was don't run them without component cooling 25 water for more thin seven minutes due to motor lO l ALDERSON REPORTING COMPANY, INC. l l 400 VIRGINIA AVE, S.W., WASHINGTON, D.C. 20024 (202)554-2345

28G l () 1 considerations and ten minutes due to seal considera tions. 2 So they were still very concerned about the integrity of the 3 seals even though they had re-established component cooling 4 water flow about 4 o' clock. As a result they wanted to cool 5 down and depressurize as rapidly as possible. They 6 maintained between 65 and 70 degrees per hour cooldown rate. 7 MR. KERR What would you have told them to do 8 differently than they did? 9 MR. JORDON: I believe that our instructions would 10 have been to repressurize rather than to play with that. 11 MR. KERR* So you would have taken over control of 12 the reactor? 13 MR. JORDANS Not without activating the center p \\- 14 clearly. We would have been in an advising mode. 15 MR. KERRs I thought you said you wouldn't have 16 activated the center with that inf o rm a tion. 17 MR. JORDANS Yes. I will try again. We wculd be 18 in an advising mode and we would be recommending to then to 19 repressurize. 20 MR. KERR: Let's not play games. Would you ha ve 4 21 told them to repressurize or not? 22 MR. JORDON: I would not have ordered them to 23 repressurize at that point. O (_) 24 MR. KERR You would have said, I think that is 25 the thing to do, but you wouldn't have ordered them? r ('V) l ALDERSON REPORTING COMPANY, INC. 400 VIRGINIA AVE. S.W., WASHINGTON, D.C. 20024 (202)554-2345

287 () 1 MR. JORDANS We would have asked them to consider 2 it at that point. That is correct. 3 MR. BLACKWOODs I think I would have addressed the ( 4 pump seal integrity. They had re-established cooling water 5 flow to the pumps and chances are there was really no great 6 need to depressurize at that rapid a rate. In other rords, 7 if it slowed the thing down, then either ambient losses or 8 heat conduction through the upper head down into the other 9 reactor internals would have --- 10 MR. KERRs Did they have a sr ft technical 11 advisers *t 12 MR. JORDAN Yes, they did. 13 MR. BLACKWOOD: Yes. They had about six shift 14 technical advisers. 15 MR. KERR Those guys would have apparently 16 reached different conclusions than you would have, I gather, 17 because in retrospect you would have told them not to 18 depressurize. 19 MR. BLACKWOOD: ho. I would have explored wa e the r 20 or not their concern for the integrity of the reactor 21 coolant pump seals was great enough for them to continue to 22 depressurize at this rapid a rate. 23 MR. KERR: Well, clearly it was because that is () 24 what they did. 25 MR. JORDANS Let me go back to the seals' then. \\v) ALDERSON REPORTING COMPANY, INC. i 400 VIRGINIA AVE, S.W., WASHINGTON, D.C. 20024 (202)554-2345

283 . ~ - () 1 The seals had had cooling water re-established. The pumps 2 were not running. 3 MR. KERR: I am not trying to judge which group of 4 people would have made the better judosent. It seems to me 5 from what went on that they had a shift technical adviser I 6 and other advice. They reached a conclusion. What I seen 7 to be hearing is that you gentlemen would have reached a 8 different conclusion with the same data. Am I missing 9 something? 10 MR. JORDAN: I think we would have reached it 11 perhaps sooner and would not have wanted to continue toying 12 with a bubble in the reactor. 13 MR. LEWI5s You are dealing with a very important w 14 question here if you decide that they ought to 15 depressurize. You started out by saying you would recommend 16 it and then backed off to saying that you would recommend 17 that they consider it and those are two different things. 18 I know that in the aviation business the game is 19 played that everything that FAA tower controller cays to me i 20 is purely advisory. He never gives me order s. But if I i 21 -disobey his advice they will lift my license and not for .l 22 disobeying the orders but for operating the airplane 23 recklessly. () 24 When you give advice to an operator at a plant I 25 which is in trouble he is going to have this kind of thing I-l S ALDERSON REPORTING COMPANY. INC. 400 VIRGINIA AVE. S.W., WASHINGTON, D.C. 20024 (202)554 2345

289 g s 1 running through his mind and I think he is not going to be -\\s 2 dealing with the legalisms of whether you sa y to him is 3 advisory or mandatory until these things are really 4 unscrambled which may be years. So this is a test case for 5 a very important issue. 6 MR. JORDAN: I understand, but I wouldn't want to 7 disrupt the discussion of St. Lucie for it. I would be 8 willing to go into it in much more detail if you wish. 9 MR. BENDER: How much interviewing and discussing 10 of the event is being carried on with the opera tors no'w? I 11 am more concerned with the matter of just the communications 12 problem that arises at a plant like this since you now have 13 the shift technical advisers. It is a pretty good test case ,e s) s 14 of how effectively the internal manning arrangement is. 15 MR. JORDAN: In terms of this even t how much 16 interviewing we have done? 17 MR. BENDER: Yes, just to see whether the new 18 arrangement is doing things. Who is making the decisions? 19 The fact that there were six technical advisers there, was 20 that better or worse than having none, among other things. 21 MR. BLACKWOOD: We asked the licensee during a 22 meeti.ng on June 20th that specific question and they said, 23 yes, the presence of six technical advisers, in fact they (. ) 24 cancelled classes that day so there were six of them, six 25 shift technical advisers and about seven other people who j i l .g ALDERSON REPORTING COMPANY, INC. . 400 VIRGINIA AVE, S.W., WASHINGTON, D.C. 20024 (202) 554-2345 r- +

290 () 1 were once they realized that there might be a valve line-up 2 problem vera doing valve line-up checks. 3 MR. BENDER: If that event had occurred instead of 4 at early in the morning and in time for the morning crew to 5 come on but instead it occurred say about midnight what 6 would have been the manning capability? What would they 7 have had? 8 MR. BLACKWOOD: Whatever the plant manager deemed 9 necessary. He was there very early in the morning. I don't 10 know the exact time. 11 MR. BENDER: I am talking about at midnight. I am 12 not talking about early in the morning. If the same event 13 had occurred at midnight so that it was just about shift /~'T \\"# 14 change time and the plant manager wasn't going to be there, 15 and there was just the shift supervisor and the shift 16 technical adviser what would be the manning action? Would I'7 they just stay with what they have got to sort it out? 18 MR. BLACKWOOD: I guess you misunderstood me. The 19-plant manager arrives I think before five in the scrninc and 20 the operations supervisor was there it that time, too, which 21 is significantly before their normal work day. So I would 22 expect that at any time of the day or night their response 23 would have been same and it would have been hic decision as 1 () 24 to how many extra people he needed. 25 MR. BENDEP: I guess I was sort of leanine to the (~) v s ALDERSON REPORTING COMPANY, INC. 400 VIRGINIA AVE. S.W., WASHINGTON, D.C. 20024 (202) 554-2345

291 () I fact that sometimes the plant manager is out on the town, 2 for example, and when that happens -- well, I don't want to 3 go further. 4 MR. MATHIS: I have got a question. What would 5 have happened if you had time to analyze what would have 6 happened if the reactor coolant pumps hadn't been tripped? 7 MR. BLACKWOOD: Eventually the seals would have 8 failed, but their operating procedurea limit the time that a 9 reactor will function and be operated without flowing 10 cooling water for ten minutes. 11 MR. MATHISs I am well aware that they could be 12 tripped but I don't know that it is tied to seal water. 13 MR. OKRENT4 They trip to their instructions and 1-4 not NRC instructions. 15 MR. MATHISs They trip to save the seals. 16 MR. OKRENT: Yes. 17 MR. EBERSOLE4 This is a ;E plant. It doesn't 18 have PRVs and block valves, doesn't it on the pressuriner. t 19 MR. OKRENT: Yes. It has a PRV and one block 20 valve. 21 MR. EBERSOLE: Was it possibly con tem pla ted that 22 they were close to the edge of repressurizing on the 23 - charging pumps and going ahead and making it water solid at (')1 (, 24 2200 to fill it and collapse the bubble? -s MR. BLACKWOOD4 At 2200 pounds? 0 \\_/ l ALDERSON REPORTING COMPANY, INC. I-400 VIRGINIA AVE. S.W., WASHINGTON, D.C. 20024 (202)554-2345

292 1 MR. EBERSOLE: Yes. (} 2 MR. BLACKWOOD: Ihey didn't even form the bubble 3 until they passed below approximately 900 pounds. O 4 MR. EBERSOLE: I know. What happened is you 5 cooled the plant. You bought it down in temperature and 6 that is when the bubble started, right? 7 MR. BLACKWOOD: Yes. 8 MR. EBERSOLEs Had they stayed up at natural 9 convection would they have had this bubble? 10 MR. BLACKWOODs No. 11 MR. EBERSOLE: Could they have gone back? 12 MR. BLACKWOOD: You mear. maintain pressure? 13 MR. EBERSOLEs Yes. The pump seals would have 14 leaked? 15 MR. BLACKWOOD: Pardon me? 16 MR. EBERSOLE: Would the pump seals have been i 17 ruined at sta ti c, without cooling on taem if the shaft was i 18 static? If the shafts rete not turning but pressure was on 19 them would they have'been bothered? 20 MR. BLACKWOOD: They proved that they weren't 21 bothered for an hour and a half. 22 MR. EBERSOLE: Yes. 23 MR. BLACKWOOD: They basically maintained () 24 temperature at 540 degrees or so initially until commencing 25 the natural circulation cooldown at 3 o' clock. So durinc O ALDERSON REPORTING COMPANY. INC. 400 VIRGINIA AVE. S.W., WASHINGTON, D.C. 20024 (202)555-2345

293 (~'i 1 that period of time the seals were without cooling water and V 2 there was what they believe to be possibly some steam snd 3 two-phase flowing in the control feed-off line back to the s _]. 4 line control. So they did experience some high temperatures. 5 MR. EBER50LE: Thank you. 6 MR. BLACKWOODs They were very concerned in 7 depressuring as fast as they could to get pressure off of it. 8 MR. LAWROSKI: Was there a resident inspector 9 there? 10 MR. BLACKWOOD: Yes. 11 MR. LAWROSKI4 What was his role? 12 MR. BLACKWOOD: He das there at approximaterly 5 13 a.m. 1-4 MR. LAWROSKI What kind of role did he play in 15 that? 16 MR. BLACKWOODs He followed the licensee's action 1:7 and I believe that he was out of the control room for an .18 hour to an hour and a half or so in the morning about the 19 time that I left the operations center because it was 20 basically a natural circulation cooldown and they were 21 expected to got on shutdown cooling by 9 o' clock in the 22 morning. Then he came back in a little bit later in the 23 morning and also beca.de concerned over the pressuricer leval () 24 trace. About 11:30,-close to the same time as th e licensee 25 elected to call the operations center, he asked them exactly b ALDERSON REPORTING COMPANY, INC. 400 VIRGINIA AVE S.W., WASHINGTON. D.C. 20024 (202)554 2345

r,*- 29i 1 the same question, don't you think that maybe you should (} 2 call the operations center on this and the licensee said, 3 yes, we are in the process of doing that right now. 4 MR. MOELLER: Was the cooldown always within tech 5 specs? 3 MR. BLACKWOOD: Yes, it was. 7 Let's talk briefly about reactor coolant pump seal 8 performance. Starting down here with the Byron Jackson 9 pumps, they have a controlled bleedoff to volume control 10 tank or approximately 1 to 1.1 gallons per minute. There is 11 no seal injection and it is a three-stage seal plus a vapor 12 seal. There is a picture of that about three slides back. 13 Let's talk about the component cooling first and 14 then we will get into the seal designs. As I said, they ssw 15 some erratic indications in tha control bleedoff line to the 16 volume control tank which caused them to believe that they l'7 probably had steam in the seals. 18 Now, it was approximately 25 minutes after ther 19 _d lost seal water that they received the high tem pe ra ture 20 alarm in the first stage seal cavity which is set at 250 21 degrees. The vendor's recommendation is that we get that 22 alarm and inspect the seals for damage due to thermal 23 transient. () 24 There was no leakage through the vapor seal into 25 the containment other than the 50 ounces per hour or ALDERSON REPORTING COMPANY, INC. 400 VIRGINIA AVE. S.W., WASHINGTON D.C. 20024 (202)554-2345

29t5 () I whatever the design number is. In other vor the leakage 2 up through the seals during the component cooling water i 3 outage was back to the volume control tank which is the 4 normal flow pattern. 5 After they shut down and depressurized and got the 6 seals out, they inspected all the seals and found no damage 7 on any of the seals. However, there was quite amount of 8 heat checking noted on the carbon rings where the runninc 9 contacted the carbon ring. 10 MR. KERRa What does heat checking mean? 11 MR. BLACKWOOD: Well, in this case based on 12 observations by a person in AEOD who was down at the site 13 Monday and Tuesday, it is a srries of radial lines that 14 cross the small band where the running contacts the carbon l 15 face. 16 MR. KERR: Thank you. J 17 MR. BLACKWOOD: The vendor said that this is l 18 something that they would probably expect to see sfter the 19 seal had been running for some period of time. Se it is not 20 really attributed to passing steam through them. The 21 indications were basically just a reflection. Ycu could see n these lines visually, but to run your hand around the 23 sealing surface you couldn't feel any cracking or anything () 24 like that. There were no grooves, no scoring or anythin; of 25 that nature. They did replace all the seals. I ALDERSON REPORTING COMPANY, INC. 400 VIRGINIA AVE, S.W., WASHINGTON, D.C. 20024 (202)554-2345

29G

e. - -

() 1 MR. EBERSOLE: May I ask you something. What 2 seess to be developing here is that they overrun and natural 3 convection cooling functions. You haven't mentioned what gmd 4 they were doing to the secondary. Were they driving that 5 pressure down to maintain a good high differential from 6 primary to secondary as they brought primary pressure down 7 to keep a coupling between primary and secondary before they 8 got on shutdown cooling? 9 MR. BLACKWOOD: Well, they initially steamed the 10 generators down to about 20 percent early in the morning. t 11 MR. EBER50LEs How many psi? I mean that is what 12 gives you the differential from primary to secondary is what 13 the psi difference is. f)/ s~ 14 MR. BLACKWOOD: Yes. Well, they were bypassing 15 the condenser until they broke back and then after that they 16 used atmospheric steam belts. 17 MR. EBERSOLEs What was the pressure on the 18 secondary side? Did they not overrun the natural convection 19 system? 20 MR. BLACKWOOD: What do you mean " overrun it"? 21 MR. EBER50LE: Well, they didn't cool the p r ir.a r y 22 fast enough consistent with the pressure reduction. 23 MR. BLACKWOOD: No, they cooled it. '( ) 24 MR. E3ERSOLE: They didn't cool it fast enough. 25 They reduced the pressure. (s s Al.DERSON REPORTING COMPANY. INC. 400 VIRGINIA AVE. S.W., WASHINGTON. D.C. 20024 (2C2) 554 2345

297 (} 1 MR. BLACKWOOD: No. They cooled it too fact. 2 M3. EBER50LE: Well, I am talking about consistent 3 with the te m pera ture. O 4 MR. NOVAK: The problem is you may have had some 5 hot water up in the upper head. I think we have a brief 6 presentation. There is a stratification of hot water. The 7 question then is how quickly does that hot water cool down 8 as you depressurize. 9 MR. EBERSOLE: Well, you get the temperature down 10 by passing it to the secondary before you go to shutdown 11 cooling. 12 MR. NOVAK: Yes, but that water in the upper head 13 is not moving. 14 MR. EBERSOLE: Yes, unless it is just diffusion' 15 mixed. There must be some programmed rate to do this which 16 must have been overrun. 17 MR. JORDAN: That is the problem. There was not a 18 programmed rate for natural circulation. 19 MR. EBERSOLE: Now there will be, right? 20 M3. JORDAN: That is right. 21 MR. EBERSOLE: Tha t is what I am after. 22 MR. JORDAN: They were following and saying 23 subcool for force circulation and they were keeping th2ir T~) 24 subcool margin, you know. They were seeing this and seeing i %s 25 a void. ALDERSON REPORTING COMPANY, INC. 400 VIRGINIA AVE. S.W., WASHINGTON, D.C. 20024 2021554 2345

r; - 295 1 MR. EBERSOLE It is surprising to hea r there (} 2 wasn't a programmed shutdown rate like this. 3 MR. JORDANS I agree. O 4 4 HR. EBERSOLE Is it everywhere like that? 5 M3. NOVAK One point. This is the second time 6 that that plant has cooled down on natural circulation. I; 7 is my recollection that it has occurred once before, and it 8 is also my recollection that that is the only plant that has 9 ever cooled down on natural circulation. 10 ER. EBERSOLE: Is that so. 11 MR. JORDAN: Let me tell you the other bad part of 12 the story though. We resurrected the charts from the 13 previous cooldown and had the same sawteeth in it. () 14 ER. BLACKWOOD: I have them in about three slides. 15 Here is the reactor coolant pump. There is either 16 this picture or if you want to refer to the next one it is 17 in a little bit more detail. Here is the seal cartridge, 18 here is the integral seal cooler and the thermal harrier 19 area is down here in a water jacket that is in the pump 20 cover assembly. 21 Now let's home in c4 that just a little bit. The 22 pump cooling water injection is here. It splits and part of 23 it goes through the concentric tube heat exchanger here () 24 which is tha seal cartridge or seal cooler. The other part 25 passes down into this water jacket into what is called the ALDERSON REPORTING COMPANY, INC. 400 VIRGINIA AVE, S.W., WASHINGTON, D.C. 20024 (202) 554-2345

29.9 () I thermal barrier. Now, the function of this jacket here is 2 to cool the reactor coolant as it leaks up the shaft prior 3 3 to the coolant being picked up auxiliary impeller. The d 4 auxiliary impeller right here circulates the coolant that is 5 passing up through the seals back through the tube second of 6 this concentric tube heat exchanger and cools it. So there 'sa closed cooling path right here and this is reactor i 7 8 coolant that is passing through there. Then that control 9 bleedoff that is coming up through the termal barrier comes 10 up right here and this is approximately 1.1 or so gallons 11 per minute f or all four seals with all three seal stages in 12 tact. 13 Component cooling water is what they lost. Once 14 they re-established it they got cooling back to this water 15 jacket area and cooling back here, although the pump was 16 secure so there was no reactor coolant flow in the 17 concentric heat exchanger. They had to start flowing 18 through,the thermal barrier which is actually where it 19 cooled the seals down because there was a continuous bleed 20 rate of approximately one gallon per minute. 21 This is the type of seal on this particular 22 variety, the Byron Jackson pump. This is the seal runner. 23 Its face is I think titanium carbide and the seal ring is a (). 24 hard carbon material. This is the first stage. The 25 auxiliary impeller is here. This is the first stage seal, O> ~- ALDERSON REPORTING COMPANY, INC. 400 \\ RGINIA AVE. S.W., WASHINGTON D.C. 20024 (202) 554 2345

300 (~) 1 the second stage seal and the third stage seal. The V 2 controlled bleadoff coming off this way, and up here is 3 another seal called a vapor seal with a lead off of 50 0x's 7sO 4 per hour. The vapor seal was not damaged. 5 MR. EBER50LE Does that direct water? 6 MR. BLACKWOOD Yes, it directs it. 7 MR. EBERSOLE: They don't have a seal injection? 8 MR. BLACKWOOD: Yes, that is right, there is no 9 seal injection for this plant 10 Questions on seal performance? 11 (No response.) 12 Very briefly let's talk about steam voiding 13 indications. As I said variations in pressuriner level wero () 14 up to ten times the charging flow rate. Tf.e ramp up during 15 auxiliary spray was due to collapsing the steam bubble in H5 the pressurizer allowing the void to form in tne reactor 1:7 vessel and to axpand in the reactor vessel. The pressurizer 18 level decayed back down again due to reheat of the, stear 19 bubble in the pressurizer. 20 Right scound.6:15, that is when they first noted 21 an anomalous pressurizer level indication, and that was as 22 they passed through a pressure of about 900 pounds. Now the 23 saturation temperature for 900 pounds or so is roughly (]) 24 around 500 degrees I believe. No, excuse me. It is about 25 536 or 537 degrees. By this time at 6: 16 the reacter (v~) ALDERSON REPORTING COMPANY, INC. 400 VIRGINIA AVE S.W., WASHINGTON, D.C. 20024 (202)554-2345

l l 301 1 (} 1 coolant system bulk temperature was down about 200 degroes 2 cooler. It was maybe 350 or 346 or something like th a t. 3 By seeing the first indication of a void in the O 4 vessel at 900 pounds suggested that there was probably 200 5 degrees that had built up as a result of cooling down the 6 natural circulation at a rate of 65 to 70 degrees Fahrenheit 7 per hour. 8 Now, based on the amplitude of the swines in 9 pressprizer level we estimate that the void in the reactor 10 vessel could have been as large as appror.imately half of the 11 pressurizer volume which is 700 cubic feet or so. That 12 would have taken the reactor vessel water level down to 13 possibly slightly below the vessel plan. So it was still I 14 would say 12 feet or more above the top of the core, but 15 based on that volume estimate that is about where the water 16 level would have been. 17 The pressurizer level variations were controlled. 18 They were not uncontrolled oscillations because the licensee 19 realized they were probably causing them by shifting his 20 charging punp disenarge inte auxiliary spray the celd ice. 21 Tnere was a previous cooldown on the 15th of 1.pril 22 in '77, due to a loss of controlled air which did exactly 'hing to the component cooling water as to the 23 the same c IT 24 reactor coolant pumps. s/ 25 ER. KERRs At what point did the operator ALDERSON REPORTING COMPANY, INC. 400 VIRGINIA AVE, S.W., WASHINGTON. D.C,20024 (202) 554-2345

~. () 1 recognize waat was probably occurring? 2 MR. BLACKWOODa Between 7 and 7430 they had a 3 pretty good feel. 4 MR. KERRs So in some sense they had this thing 5 under control? 6 MR. BLACKWOOD: Yes, and to cool down and 7 depressurize, that is really the only option that they had 8 was to altarnate charging back and forth and genera te the 9 sawtooth level. 10 MR. MOELLER: Did they ever in the sequence 11 actually have a leak then, I mean a significant leak of 12 coolant? When you mentioned earlier about the raw water 13 storage tans 14 MR. BLACKWOOD: Yes, th'at is the next thino after 15 the anomalous solid plant indications. 16 MR. EBERSOLE: When he put it on shutdown cooling 17 what.was the pressure in the secondary? 18 MR. BLACKWOOD Well, let's see. 19 MR. EBER50LEs Was it still a heat sink or was it 20 a source? 21 MR. BLACKWOOD: I have the data sheets back in my Z2 briefcase. 23 MR. EBER50LE: I would think it should still be a () 24 sink; that is, you should lead on the secondary. 25 MR. BLACKWOOD: Well, let's see, by 12: 15 ther mU ALDERSON REPORTING COMPANY, INC. 400 VIRGINIA AVE, S.W., WASHINGTON, D.C. 20024 (202)554 2345

e 303 (') I were down at about 250 to 260 degrees. IMR. EBERSOLE: On the primary. 2 3 MR. BLACKWOOD On the primary. f-V 4 MR. EBERSOLE: Well, the secondary ought to be well, for that matter why wasn't it 5 down, you know, like 6 subatmospheric? 7 MR. BLACKWOOD: Well, for 260 degrees, what do you 8 have, 12 pounds, something like that, not very much. Not 9 really enough to drive very much steam. 10 MR. EBERSOLEs Right, it wouldn't have mattered 11 much. 12 MR. BLACKWOOD: That is why they steamed the steam 13 generators down early in the morning so that when they got ( 144 close to shutdown cooling they could go ahead and fill the 15 steam generators at the high of the indicating range which 16 gives them that extra one shot of cooling even though they 17 had low steam pressures to allow them to get on shutdown 18 cooling. 19 MR. EBERSOLE: Well, it wasn't subatmospheric, was 20 it? 21 MR. BLACKWOODs No. They had broken vacuum at 22 5:30, something like 5:30 in the morning. 23 MR. LAWROSKI May I ask a question. () 24 MR. BLACKWOODs Yes. 25 MR. LAWROSKIa At the event that you locked at ) v ALDERSON REPORTING COMPANY, INC. 400 VIRGINIA AVE, S.W., WASHINGTON, 0.0. 20024 (202) 554-2345

s 304 ('3 1 that occurred some time ago, do you think there was a steam us. 2 bubble there, too? 3 MR. BLACKWOOD: Well, that is this slid.' righ t 4 .here. The top traces the 4s15 event. You don't see it here, 5 but it is indicated on your handout. The top one is the 6 Junn 11th event. This one is April 15th, 1977. Down in 7 this region towards the end of the cooldown, and this 8 cooldown, I believe it was delayed for about three hours in 9 getting started and then -- I am not sure about the cooldown 10 rates. I think they were slightly less than what they had 11 up here. Down towards the end of this cooldown you see in p'essurizer level's 12 again the characteristic rapid rises r 13 and you cannot charge the plant that fast. That is, I don't /"%-) 14 know, a factor of 10, something like that. 15 M3. LAWROSKIs How big might have been the bubble 16 then ? 17 MR. BLACKWOOD: A rough estimate would be if the 18 amplitude of these swings would indicate the amount by which 19 the void in the reactor vessel had to expand to cause the 20 water to surge into the pressurizer. Sone of these were 21 about 50 percent of pressurizer level. This is maybe 25. 22 MR. KERRs I think that is as much of an answer as 23 you want, isn't it? () 24 MR. LAWROSKI: Yes. Thank you. 25 MR. BLACKWOOD: There is crior indication of this NO ALDERSON REPORTING COMPANY, INC. 400 VIRGINIA AVE. S.W., WASHINGTON, D.C. 20024 (202)554-2345

335 f'J) 1 happening. 2 Now, I mentioned that they did see anomalous solid 3 plant indications there after they turned the LPSI pump on 4 at time 1227 alth; ugh they had cons *, ant pressurizer level in 5 the cold calibrated and hot calibrated level instrument. 6 There are many 0.'s tula tio n s, if you will, on why 7 the plant responded this way, and this is a little bit of 8 background on the miniflow and recirculation valves 9

ssociated with the low-pressure pumps.

Miniflow values 10 were opened at 6:30 in the morning for a system. arm-up. 11 The 1B miniflow line was shut when that pump was put on 12 shutdown cooling about time 1051. At time 1500 they found 13 that they could get another half turn to a turn in the shut (~/ \\ \\- 14 direction on that miniflow valve. 1 15 MR. OKRENT What is that, an annual? 16 M3. BLACKWOOD: Yes, that is an annual valve. 17 The next slide I think is a good illustration. It 18 is simplified, but it is a good illustration of these 19 things. There is a common recirculation line for the two 20 low-pressure pumps and the three high-pressure pumps. That 21 is indicated on the system diagram. There are two series 22 isolation valves in_that miniflow recirculation line that 23 are locked open so that under no conditions would the safety () 24 injection pumps be without the capabilty of having 25 _ recirculation back to the refueling water storage tank in an l ALDERSON REPORTING COMPANY, INC. 400 VIRGINTA AVE, S.W., WASHINGTON, D.C. 20024 (202)554-2345

30G 1 injection phase. {} 2 Now, at time 1227 they got into what I would .3 consider an off-normal system lineup in that one pum p was 4 taking suction on the refueling water tank and the other 5 pump was-taking suction on the reactor hot leg in the 6 shutdown cooling mode. Both of these were discharging into 7 a common discharge header back to the reactor cold leg. The 8 miniflow line on the 1A pump was open because they thought 9 that that pump was basically -- vell, that pump was 10 basically deadheaded. It was run.41ng very close to the 11 shutoff hesi condition. 12 Now this, as I said, is one postulation of how the 13 water got back into the refueling water tank. The concern () 1,4 here is that reactor coolant getting into the refueling 15 water tank represen ts an unmonitored release pa th 16 particularly for the nobel gases and dissolved cases that 17 would come out of-solution and go out the atmospheric path. 18 The vent under refueling water tank is not monitored. The 19 tank is outside. 20 There are other possible flow paths back to the 21 refueling water tank. We are not sure right now and neith?r 22 is the licensee on how the water got back there. The volune 23 of water in the refueling water tank increased by () 24 approximately 5,000 gallons, four inches or so, up-until tha 25 time when they turned off the pump on recirculation and shut (~h v i ALDERSON REPORTING COMPANY, INC. 400 VIRGINIA AVE, S.W., WASHINGTON, D.C. 20024 (202) 554-2345

397 (} 1 the motor operated isolation valves. They would be up 2 here. I haven't put them in, but they would be up in this 3 area. O 4 MR. KERR: You got that information from a level 5 chart or something? 6 MR. BLACKWOOD: Yes. It is basically one pen 7 width. 8 MR. MOELLER: You say an unmonitored release path, 9 but did they detect any nobel gases airborne? 10 MR. BLACKWOOD: No. 11 MR. MOELLER: Is there a monitor? 12 MR. BLACKWOOD: No, there is no monitor. It is a 13 12-inch pipe with a hooded vent. The tank is located 14 outside. The tank at the time had a little over 500,000 of 15 borated water in it, but it is outside. 16 MR. BENDER: There have been a number of 17 discussions about level indications. In there any level 18 indicator that has been proposed so far that would tell you 19 about the existence of that steam bubble? 20 MR. BLACKWOOD: Yes, that has been proposed. 21 MR. BENDER: No, I say are the ones that have been 22 proposed capable of telling you what was happening in that a event? f) 24 MR. BLACKWOOD: I would think so. s j 25 MR. JORDAN: That is exactly what they are ALDERSON REPORTING COMPAN(, INC. 400 VIRGINIA AVE, S.W., WASHINGTON, D.C. 20024 (202) 554-2345

308 /] 1 proposed for. U 2 MR. BENDER: I know that is what they are proposed 3 for. I want to know whether the level indicators that have .O 4 been proposed can tell what is happening in that particular 5 vent. Most of them are based on some static condition and 6 I would like to know whether any of them are useful in this 7 dynamic circumstance. 8 MR. JORDAN: This was very slow dynamics though. 9 MR. BENDER: Well, maybe. 10 MR. KERR How many inches rise in level does that 11 5,000 gallons represent roughly. Do you know? 12 MR. BLACKWOOD: Four inches in the refueling water 13 tank, 50,000 gallons per foot. If a differential pressure 'ry (/ 14 type of an instrument is used the trace in pressurizer levsl 15 shows that it is certainly capable of responding fast enough 16 to these transient conditions to give you an indica tion. 17 MR. KERRs Fine. Thank you very much. 18 MR. OKRENT: This water presumably came from the 19 power system or where? 20 MR. BLACKWOOD: They were charging at 99 gallons a 21 minute. They saw no increase in pressurizer level and they 22 were seeing no iacrease in pressure. Some of this water may 23 have been going into collapsing the void in the reactor () 24 vessel. We are not sure when the void in the reactor vessel 25 had collapsed, but there was 5,000 callons more in the n v' 4 ALDERSON REPORTING COMPANY, INC. 400 VIRGINIA AVE, S.W, WASHINGTON D.C. 20024 (202)554-2245

309 O 1 refueling water tank when th ey got done than there was when V 2 they started. A 3 MR. OKRENT: My question was where was there 5,000 V 4 gallons less? 5 MR. BLACKWOOD: Well, if you track it all the way 6 back, the volume control tank was on automatic make-up so I 7 expect that they saw a reduction in whatever pure water tank 8 went on service. 9 MR. OKRENT: Did somebody check that? 10 MR. BLACKWOOD: I don' t have confirmation of that. 11 MR. EBERSOLE: Isn't there a spray inside the 12 vessel head? 13 MR. BLACKWOOD: No, no overhead injection. 14 This is a simplified diagram of the low-pressure 15 safety injuction system. Pump 1B was taking a suction from 16 the hot leg, loop B, through the pump. The miniflow valve 17 was shut when they on. This the valve thet they found had 18 cracked open and was shut further around 1 o' clock. This 19 valve was open and basically throttled so that the flov 20 reactor coolant is in through the pump up thic way into the 21 the shutdown cooling heat exchanges which are in the core 22 spray lines back around this flow control valve and inte the 23 cold legs in both loops. O 24 "= - co"c"cre=ttr it" ** * '^ a="a e ru""1"c 25 taking the suction from the refueling water storage tank ) \\/ ALDERSON REPORTING COMPANY, INC. 400 VIRGINTA AVE, S.'N., WASHINGTON, D.C. 20024 (202) 554-2345 l I

310 1 again into this common-discharge header. The path from hre {} 2 into the system is the same, part of it going through this 3 valve that was opened or throttled and the rest of it going O 4 through one of the' auxiliary snutdown cooling heat 5 exchangers. The miniflow valve was open because they had 6 intended basically to deadhead this pump on the system in 7 order to take water from the refueling water storage tank 8 and get it into the reactor cooling system and get the 9 pressurizer f ull of water as soon as they cruld. They could 10 do that because of the high flow rates that are available 11 with these low pressure saf ety injection pumps. 12 Now, as I said, this is a common miniflow 13 recirculation line. There are 53 hifden pumps, =iniflows (') \\_/ 14 that are dosn here and the two low-pressure safety injection 15 pumps are in there. Of course, spray recirculation also 16 goes back to the refueling water storage tank. 17 There are some other theories about leaking check 18 valves letting water back this way since this pump aas 19 deaiheaded back into the tank. Another alternative would be 20 I believe these two valves were shut when they started this 21 pump and recirculation. If these two valves were not shut 22 or weren ' t fully shut this pump would have been taking a 23 common suction on the refueling water tank at elevation head I '1 24 pressure and the reactor coolant system in this situation at k/ 25 roughly 200 pounds. ALDERSON REPORTING COMPANY, INC. 400 VIRGINIA AVE, S.W., WASHINGTON, D.C. 20024 (202) 554-2345

l 311 ,( ) 1 MR. OKRENT: If you didn't happen to have changing 2 pumps available than would this have been a way of emptying 3 the primary system? ~ 4 MR. BLACKWOOD: If you didn't have charger pumps 5 you couldn't pump it out. 6 MR. OKRENT: Let me say we got down to the low 7 pressure and then we had this line up and we 1 cst the 8 charging pumps. Could we then have been in a position of 9 unknowingly at least pumping water from the primary syctem 10 back into the refueling water storage tank, if I understand 11 correctly? 12 MR. BLACKWOOD: That probably would not happen. 13 As long as this pump is running and taking suction there and 14 keeping this header at 200 po'unds or something like that I 15 think the primary system would stay full. Now, that would 16 t9 a situation where the primary system would rtay full at 17 300 pounds and whatever water, there would just be a 18 transfer of reactor coolant back into the refuelinu water 19 storage with a corresponding suction of the same amount to 20 keep the primary system full. The reason that you saw an 21 increase in the refueling water tank level I think is Z2 because we were charging and there was an excess of water 23 that had to go some place. () 24 MR. OKRENT: You can only charge is there is an 25 empty spot.. o ALDERSON REPORTING COMPANY, INC. 400 vtRGINIA AVE S.W., WASHINGTON, D.C. 20024 (202)554-2345

312 1 MR. BLACKWOOD: Not with a positive displacement 2 charging pump. j 3 MR. OKRENT: You would have opened a safety relief 4 valve. So in other words, there was an empty spot in the 5 primary system. 6 MR. BLACKWOOD: Yes. 7 MR. MOELLER: Is someone checking all of this out, 8 the licensee? 9 MR. BLACKWOOD: They are not satisfied with the 10 explanation of the licensee as given as such. 11 MR. MOELLER: So you are asking for better? 12 MR. BLACKWOOD: Yes, we are. 13 MR. MOELLER: What is the status now of the plant? -( ) 1,4 MR. BLACKWOOD: Ihe plant, as I said, started up 15 on June 30th and achieved a hundred percent power on July 16 1st and has remained at 100 percent power. 17 MR. BLACKWOOD: That concludes what I had to say. 18 Brian. 19 MR. SHERON: I am just briefly going to tell you 20 what we are doing with regard to the upper head voiding 21 question. 22 The upper head voiding can occur during transients 23 and accidents which would depressurize the primary system. ("T 24 The concern that I guess we would raise over it is is it %) 25 being properly accounted for in the models as they calculate s () ALDERSON REPORTING COMPANY, INC. 400 VIRGINIA AVE. S.W., WASHINGTON, D.C. 20024 (202)554-2345

313 /~' 1 intransients and accidents say with Chapter 15 analysis. \\n)1 2 Some of the models, the vendor models don't account properly 3 for the upper head region and also they may not account for b) 4 the structure on the upper head region which could be a 5 source of heat which would tend to hold the upper head fluid 6 at a hotter temperature. 7 Just quickly, this is a combustion vessel and you 8 can see this region up here, this upper head plate here. 9 During pump force conduction flow there is a circulation 10 pattern up here which would tend to put the fluid into the 11 core in some reasonable communication with this fluid up 12 here. 13 During natural circulation flow, however, the (h Ns) 14 momentum of the fluid into the core would net probably be 15 enough to penetrate all the way up to this region and this 16 region up here would be relatively stagnant with recpect to 17 the fluid down here. 18 We took a brief look at this upper head voiding 19 and we did not see any direct safety problems with regard to 20 combustion plants or PWRs in general. By no direct safety 21 problems what I mean is that nothing stuck out and gla re d 22 right in our face.that if this happened during scoe event it 23 would obviously cause an unacceptable situation. [^)T 24 Some of the things though that we did see were u 25 that the unexpected voiding which did occur produced an O ALDERSON REPORTING COMPANY, INC. 400 VIRGINIA AVE S.W., WASHINGTON, D.C. 20024 (202) 554-2345

314 ("s) 1 anomolous plant behavior which initially confused the u 2 operator which is not a desirable situation. We also said 3 there may be other transients or accidents lurking around O 4 which this voiding may affect in some fashion which we just 5 don't know yet. 6 What we believe was necessary to resolve the 7 problem was to form a systematic detailed evaluation 8 assessing the impact of voiding on all postulated evente and l 9 modes of operation of the plant. I 10 MR. LEWIS: What is meant by postulated events? 11 MR. SHERON: Transients and accidents. 12 MR. LEWIS All possible ones? 13 MR. SHERON: All the ones that we postulate, for O \\_/ 14 example, in Chapter 15. 15 MR. EBERSOLE: Let me pick one. Take a BEW 16 reactor, depressurize the second side and admit that the l'7 full feedwater fle w con tinues to run on. Inat is a good one. 18 MR. SHERON: ,A rapid depressuration. 19 MR. EBERSOLE: Tha t is the wo rst. 20 MR. SHERON: Like I say, we haven't done the 21 analysis. 22 MR. PLESSETs Can't hear you, Jessie. 23 MR. EBERSOLE. If you fill it full of ccid water (]) 24 it will do a great job of depressurizing the primary. 25 MR. SHERON: Well, you could postulate the steam O ALDERSON REPORTING COMPANY, INC. 400 VIRGINIA AVE, S.W., WASHINGTON, D.C. 20024 (202) 554-2345

315 (} 1 line accident. 2 MR. EBERSOLE: I just did that but I compounded it 3 by putting told water in where there was hot water on the 4 second said. 5 MR. SHERON. The effect of voiding in the upper 6 heading again is something that has to be examined. 7 One of the things that I think was pointed out 8 previously in Ed presentation was that the plant control, in 9 other words, how does one depressurize these plants during 10 natural circulation cooldown, to preclude this voiding needs 11 to be identified. This should be done and also it should be 1 12 properly accounted for in operating procedures and operator 13 training, including training the operators so that they can 1-4 identify this if and when it occurs and not be baffled by it 15 but actually know what it is and what action to take. 16 The licensee, which is Florida Power and Light, 17 has been directed to perform the above items. This is being 18 done througn a series of requests for additional information. 19 MR. KERR: Is the voiding looked on as a serious 20 problem because it could interfer with natural circulation 21 cooling or because it could lead to core uncovery or juct 22 because it might lead to anomolous behavior? 23 MB. SHERON: Well, we asked ourselves that () 24 question and the answer was that because the thermocouples 25 at the core exit indicated a high degree of subcccling even 3(J ALDERSON REPORTING COMPANY, INC. 400 VIRGINIA AVE, S.W., WASHINGTON, D.C. 20024 (202)554-2345 l

316 /~T 1 though there was a void forming in the upper head one could V 2 say that if this void started to expand down towards the hot 3 legs as it expanded it would encounter a cooler region of O 4 fluid and condense. So then you take a step further and 5 say, gee whiz, what if it didn't condense, what if it-6 expanded down and got into the hot legs. Well, you would 7 postulate then that any steam that got into the het lenc 8 would travel into the steam generators and condense. 9 So from the standpoint of natural circulation we 10 didn't identify any situation where it could interrupt it. 11 There are events, like I said. One might be the way one 1:2 depressurizes following a steam generator tube rupture which 13 may be affected by this, and I don't know in what direction () 14 or how. We have directed the licensee to examine this. 15 Basically we said to back and lock at Chapter 15 in light of 16 this phenomena and tell us which transients or accidents l'7 migh t be af f ected and in what manner. In other vordr, are 18 your results still valid? 19 MR. KERR: But in your thinking so far you haven't 20 identified anything specific, just a general unease that 21 here is a situation that has not been looked at in detail. 22 Is.that right? 23 MR. SHERON: Yes, because it was not previously () 24 identified, the operator did not expect it and he -lid no l 25 recognize it immediately when it did. occur. (") 1 ALDERSON REPORTING COMPANY, INC. 400 VIRGINIA AVE. S.W., WASHINGTON, D.C. 20024 (202) 554-2345-

317 (} 1 MR. EBERSOLEs Isn't it generic to all P'.G s ? Why I' 2 did you just tell ane licensee? 3 MR. SHERON: Yes, it is. 4 MR. EBERS01Es You just told one licensee. 5 MR. KERR4 Excuse me. I had gotten the impression 6 that the upper head configuration of this reactor was 7 some what more conducive to this behavior. 8 MR. JORDANS Ihat is correct with regards to upper 9 head flow. It is more conducive. 10 MR. SHERON: We have thought bout this, you know, 11 should it be a generic concern, and I think it is. Be f o re 12 we go off half cocked, I guess, and request all licensees to 13 do calculations and analyses what we felt the best way to ( 14 approach it would be would be to let the licensee, Florida j 15 Power and Light, perform the analyses, the information we 16 requested and to get that back to analyze it and digest it l'7 to determine 'if there is a generic problem or generic 18 concern which should be expanded to the industry at large. 19 We have requested the coming up of a cooldown rate 20 and putting an upper head model and so forth in your 21 transient calculations. That probably would calculate 22 this. That information I believe we requested for 30 days 23 upon receipt of the letter and the remaining information 60 ()' 24 days at which time we would get back the responses, evaluate 25 them and determine whether f urther action was needed on a O ALDERSON REPORTING COMPANY, INC. 400 VIRGINIA AVE. S.W., WASHINGTON, D.C. 20024 1202) 554-2345

318 (} 1 generic basis. 2 MR. OKRENT: Well, my question is really for 3 Dr. Budnitz. My' crude estimate is that we do about three (~) V 4 experiments a year and it costs $45 million. Have you 5 considered giving them $15 million for having run one of 6 your experiments? 7 (Laughter) 8 MR. MOELLER: I had a question. Was the April 9 15th, 1977, event, was that reported as an LER? 10 MR. SHERON: I would ask Ed. 11 ER. JORDAN: Yes, the event was reported, but the 12 details such as the strip chart records were not included in 13 the report. ( 14 MR. MOELLER: Well, I guess that leads to two 15 questions. One is, has anyone searched back through LERs to 16 see how many other similar events may be there? Two, I 1'7 guess you send out an all-points bulletin and you ask every 18 plant to report if th ey have had anything like this in the 19 past'as well as you alert them to this probitm. 20 MR. JORDON: Right. We sent out a circular on 21 this particular problem advising them of this event and 4 22 giving them recommendations as to how to chance their 23 procedures. Then we have our inspectors following up on the () 24 follow-up actions at the plant. 25 MR' MOELLER: Have you asked them to remind you o' O ALDERSON REPORTING COMPANY, INC. 400 VIRGINIA AVE, S.W., WASHINGTON D.C. 20024 (202)554-2345

e-319 () 1 any similar events that may have occurred at other plants in 2 the past? 3 MR. JORDAN: 'he circular doesn't require a 4 written response from the licensees. I would elabora te and 5 say that there were several NRC staff members post-TMI that 6 had concerns with regards to voids forming in the upper head 7 for this particular reason. So we had done some reviews and 8 Brian Sheron was involved in those reviews earlier. So it 9 was this particular episode that magnified it and I think 10 brought it to the point that it is now. 11 MR. PLESSET: Bob Budnitz wants to make a comment. 12 MR. BUDNITZ From this discussion it is clear 13 that there were weaknesses in the licensee's or the vendor's 14 code that weren't able to treat this phenomenon. I gather 15 that from your statement. 16 MR. SHERON: Well, it was my understanding that i 17 combustion engineering's model that is used to predict these 18 type of transients is SEESECK. That code as I understand 19 does not have an apper head region modeled in it? 20 MR. PLESSET: They don't note it separately, do 21 they? 22 MR. SHERON: I beg your pardon? 23 MR. PLESSET: They don't note that separately, do .O 24 they2 25 R. SHERON: No, they don't. ALDERSON REPORTING COMPANY, INC. 400 VIRGINIA AVE. S.W., WASHINGTON, D.C. 20024 (202) 554-2345

320 (]) 1 MR. PLESSET: So how could they do it? 2 MR. BUDNITZa I understand that. Secondly, I 3 gather we don't have a code within NRC that is capable of 4 doing that right now either. 5 MR. PLESSET: That is right. 6 MR. SHERON: I think a code like RELAP where you 7 can model that region separately would be appropriate with 8 the approprite flow paths. 9 MR. PLESSET: A one dimensional RELAP, that could 1 10 do it,.Yes, but I don't think they have ever done that. 11 MR. SHERON: We have never really used RELAP 12 extensively for transien,ts as what I would consider as mild 13 as a cool down on natural circulation which does carry out 14 over hours. s 15 MR. BUDNITZ: These incidents seem to point up one 16 after that we just have a general situation codes. There is 17 a lot that could be done and hasn't yet been done either by i 18 the industry or by us. 19 MR. PLESSET: I was going to point out, Ecb, that 20 TRACK flunked physics one. It doesn't conserve nass. 21 MR. BUDNITZ No, I didn't know that. I thought 22 TRACK concerned all the relevant points. 23 MR. PLESSETs No, Bob, it doesn't. () 24 .(Laughter.) v 25 MR. OKRENTs A code that follows a transient for O ALDERSON REPORTING COMF ANY, INC. 400 VIRGINIA AVE, S.W., WASHINGTON, D.C. 20024 (202)554-2345

321 (} 1 five hours or so forth. We need a different concept in fact. ? MR. PLESSET: TRACK gains mass, Dave, so that the 3 longer you follow it the more inventory you have got. 4 MR.'BUDNITZ: Well, th a t is great. 5 (Laughter.) 6 MR. PLESSET: Let Brian finish. 7 MR-SHERON: That was basically my presentation. 8 '.: just wanted to point out that we are looking into tha 9 possibilty of running an experiment in future semiscale at a 10 Mod. 2-A facility. I am not too sure sincn it is the head . 11 upper region of the vessel or modeled after Westinghouse's 12 UHI plant and the communication paths may be' atypical with 13 respect to a combustion plant. <~ k-) 14 MR. KERR: Are you going to try and find out if a 15 bubble cLn form in the upper head or how you can lose 5,000 16 gallons of water? 17 (Laughter.) 18 MR. SHERON: Whether a bubble can form in the 19 upper head. I know many ways to lose 5,000 gallonc of water. 20 MR. OKRENT4 By the way, with regard to 5,000 21 gallons of water, Mr. Chairman, I w'ould like to understand 22 how that really happens and whether it could occur in a 23 situation when you dida 't have charging. Not tonight but I'/ 24 either from ICE or from an ACRS file or both. s.- 25 MR. PLESSET: I think they have made note of that, () ALDERSON REPORTING COMPANY, INC. 400 VIRGINIA AVE, S.W., WASHINGTON, D.C. 20024 (202)554 2345

322 O o ve- : ae1teve **** 1cs a v o e= v== ru=the= c1=cu==1>a a 2 the GE drives, the Browns Ferry event and now this matter. 3 MR. KERRs Well, I don 't know if it is going to be O 4 4 IEE but we are going to get more discussion. 5 MR. SEISS: Be sure we note both of those requests. 6 MR. PLESSET: Are you finished, Brian? 7 MR. SHERON: Yes, I am. 8 MR. PLESSETs Thanks very much. 9 I am going to take the liberty of recessing until 10 to mo rrow at 8430. 11 (Whereupon, at 7:50 p.m., the meeting recessed, to 12 reconvene at 8:30 a.m., Friday, July 11, 1980.) 13 14 15 l 16 17 i i 18 19 20 21 22 23 O 24 25 s ALDERSON REPORTING COMPANY, INC. 400 VIRGINIA AVE, S.W., WASHINGTON, D.C. 20024 (202) 554-2345

J O NUCLEAR REGULATORY CO'C4ISSION This is to certify that the attached proceedings before the () i in the matter of: ACRS - 243rd Meeting j Date of Proceeding: July 10, 1980 Docket !!umb er : Place of Proceeding: Washington, D. C. were held as herein appears, and that this is the original transcript thereof for the file of the Commission., Mary C. Simons Official Reporter (Typed) b MM Official Repcrter (Signature) i i i

= O ~ ~ IMPLICATIONS OF UPP$R HEAD VOIDJE POTENTIAL FOR UPPER HEAD VOIDING OCCURS DURING e TRANSIENTS AND ACCIDENTS WHICH DEPRESSURIZE PRIMARY SYSTEM (E.'G., LOCA's, OVERC00 LING EVENTS ON SECONDARY SIDE) SOME VENDOR ANALYSIS MODELS MAY NOT PROPERLY ACCOUNT FOR e WEAK HYDRAULIC COUPLING BETWEEN VESSEL UPPER HEAD REGION (~]) AND THE REST OF THE VESSEL UNDER LOW-FLOW CONDITIONS SOME VENDOR ANALYSIS MODELS MAY ALSO NOT PROPERLY ACCOUNT e FOR STORED HEAT WHICH EXISTS IN METAL STRUCTURE IN THE UPPER HEAD REGION. O /

00 0 0D ] [ [ [ ] ~ es n_.q_ g _j q_ a I:! aa s [t 90*. UPPER HEAD 1 .a. \\__ b = m_ t \\ !s i 4 UPPER PLENUM r dN 4 l' m' i, 1 q "k ~ J: ' 'M V TOTAL p i l FLOW \\% k, lil p i s /- ..t _r F l l' y ggZ T4-*5T = .uiu sm) MAIN FLOW BYPAS5 FLOW (4)e = = e - 1 THRU OUTLET NOZZLE ~ CLEARANCE 4 2 THRU INSTRUMENTED CENTER G.T. "} 3 THRU SHROUD-EARREL ANNULUS A 3 4 THRU SHROUD CLEARANCE r j J 5 THRU CENTER GUIDE TUBES 62d 6 THRU CUTER GUIDE TUBES // b' J 7 THRU ALIGNMENT KEY-WAYS e ----( l i I 7 -s (v) N p I I REACTOR VESSEL FLOW PATHS O

e NO DIRECT SAFETY PROBLEMS HAVE BEEN IDENTIFIED O e fUNEXPECTED VOIDING WILL PRODUCE ANOMALOUS PLANT BEHAVIOR WHICH COULD PRECIPITATE INCORRECT OPERATOR ACTIONS TO PROPERLY RESOLVE PROBLEM A SYSTEMATIC, DETAILED EVALUATION IS NEEDED, ASSESSING e THE IMPACT OF VOIDING ON ALL POSTULATED EVENTS AND MODES OF OPERATION i OPTIMUM PLANT CONTROL (E'.G., C00LDOWN RATE) NEEDS TO BE ~ e IDENTIFIED WHICH MINIMIZES OR ELIMINATES POTENTIAL FOR V I ING DURING C00LDOWN (0N NATURAL CIRCULATION OR OTHERW O 8 THE UPPER HEAD VOIDING PHENOMENON NEEDS TO BE PROPERLY ACCOUNTED FOR IN OPERATING PROCEDURES AND OPERATOR TRAINING, INCLUDING THE-PLANT SIMULATOR.' THE LICENSEE IS BEING DIRECTED TO PERFORM THE ABOVE ITEMS. .. e BASED ON RESULTS OF AB0VE EVALUATION STAFF WILL DETERMINE' IF VESSEL VOIDING-IS G'ENERIC CONCERN FOR ALL PWR's. O-6 i-

ST. LUCIE TRIP AND C00LDOWN (6/11/80) 1. SITE DESCRIPTION II. EVENT DESCRIPTION III. REACTOR COOLANT PUMP SEAL PERFORMANCE 7 IV. STEAM VOID INDICATIONS V. ANOMALOUS SOLID PLANT INDICATIONS O 6 i O i l

ST. LUCIE UNIT NO. 1 (.,/ LICENSEE: FLORIDA POWER AND LIGHT COMPANY SITE: TWO NUCLEAR UNITS 1. OPERATING 2. UNDER CONSTRUCTION (36%, FLD 10/82) LOCATION: 12 MILES SE OF FT. PIERCE, FLORIDA REACTOR: COMBUSTION ENGINEERING PWR 2560 MWT 802 MWE ,n. INITIAL CRITICALITY: APRIL 22,1976 L.) COMMERCIAL OPERATION: DECEMBER 21, 1976 CURRENT CYCLE: CYCLE #4 (16-MCNTH OPERATING CYCLE) CRITICALITY THIS CYCLE: fMY 7,1980 RESTARTED: JUNE 30, 1980 AT 100% JULY l,1980 CONDENSER COOLING: DNCE-THROUGH HEAT SINK: ATLANTIC OCEAN /s <] I

9 EVENT DESCRIPTION INITIAL CONDITION: FULL POWER TIME EVENT /ACIION (3 V 0226 HCV-14-6 FAILED SHUT SHORTED SOLEN 0ID TERMINAL BOARD LOST CCW FLOW TO ALL RCPS 0233 MANUAL REACTOR TP,IP 0235 STOP ALL RCPS 0238 START 181 RCP TO ENCHANCE NATURAL CIRCULATION 0239 STOP 1B1 RCP 0300 START NC C00LDOWN CDR: 60-70F/HR 0350 OPEN HCV-14-6 .ilR LINE JUMPER 0600-0630 DEPRESSURIZE 1140 PSIG TO 690 PSIG ( CHARGE VIA PZR AUX SPRAY LINE 0615 PZR LEVEL VARIATIONS NOTED 0630 ~ 1230 ALTERNATE CHARGING FLOW BETWEEN PZR AUX SPRAY AND LOOPS ~ II-l O V

TIME EVENT / ACTION 0700-0730 INDICATIONS OF VOIDING OTHER THAN IN PZR (SUBC00 LING 200-150F) ({') 1051 START LPSI 1B IN SHUTDOWN COOLING MODE 1227 START LPSI 1 A IN INJECTION MODE TO G0 SOLID 1230 FZR LEVEL (HOT PEGGED HIGH) ( COLD STEADY AT 64%) NOTED ANOMALOUS SOLID PLANT RESPONSE (PRESSURE CONSTANT WHILE CHARGING AT 88 GPM) -1300 SHUT LPSI 1B MINIFLOW ISOLATION VALVE (FOUND CRACKED OPEN} 1357 NOTED SLIGHT RISE (RAMP) IN RWT LEVEL STOP LPSI lA SHUT MINIFLOW LINE MOVS SLIGHT RISE IN PZR LEVEL (COLD) AND PZR PRESSURE 1500 DRAW STEAM BUBBLE IN PZR, DRAIN TO INDICATING RANGE ,f 3 ~ 1600 NORMAL RESPONSE TO CHARGING AND LETDOWN VARIATIONS 9 II-2 \\,,) r

REACTOR COOLANT PUMP ,_s SEAL PERFORMANCE e ERRATIC CONTROLLED BLEED 0FF FLOW INDICATION e NO VAPOR SEAL LEAK INTO CONTAINMENT e VISUAL INSPECTION RESULTS NO DAMAGE SLIGHT HEAT CHECKING e ALL SEALS REPLACED e SEAL INFORMATION BYRON JACKSON CONTROLLED SLEEDOFF TO VCT 3-STAGE SEAL PLUS VAPOR SEAL s '~' e SEAL REPLACEMENT: RCP 1A1 APRIL 1977 (LOSS OF CCW) RCP 1A2 APRIL 1977 (LOSS OF CCW) ~ RCP 181 NOVEMBER 1978 (SUSPECTED CAUSE OF MOTOR PROBLEMS) RCP 1B2 OCTOBER 1979 (PLANNED MAINTENANCE) (~1 III-l

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