ML19220C694
| ML19220C694 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 04/07/1979 |
| From: | Fraley R Advisory Committee on Reactor Safeguards |
| To: | Wright R Advisory Committee on Reactor Safeguards |
| References | |
| ACRS-SM-0081, ACRS-SM-81, NUDOCS 7905140039 | |
| Download: ML19220C694 (4) | |
Text
4hhg Acms#9 N A Wr-7f7m CONERSATION BETdEEN R. FRALEY AND R. WRIGHT (THREE MILE ISLAND SITE)
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HARRISBURG, PA T
Wright:
I don't think I have any more to say other than what Lawreski and Bender transmitted this morning.
Fraley: Well now, let rue ask for clarification. Apparently when Mike called, he said that the Staff now feels that the core could, more or less, cool itself by just setting in a pot of water and by radiation and natural convection within the pot, i.e.,
the pressure vessel; it would cool itself without any external circulation water.
Dr. Lawreski wasn't too sure of that.
Is that the situation.
Wright: n at is the situation. B e Staff thinks that, all the people here also think that, and so does Dr. Lawrcski. He thinks that they can also cool by natural circulation. B ey are not going to do that, it would be used in an emergency situation.
Fraley: Bat's natural circulaticn within the core? I mean it doesn't need to go out through the external loop and through the heat exchangers. Is that correct?
Wright:
No, it would go out through the heat exchangers; through the steam generators.
Fraley:
CE, the heat would have to be removed through the steam generator.
Wright: Yes.
Fraley:
I see, CK, and everybody is convinced that they can establish and maintain natural circulation through this damaged core, is that correct?
Wright: Wat's correct.
Fraley: hhat is the basis for that since they don't know how badly the core is damaged?
Wright: Well, they are getting some circulation through there because they are still running one pump. Bere is about 5 megawatts of heat in there. Bey are still trying to take the gas out of the system.
I don't know exactly how much they have in there.
Sc they are not making any attempt to gc on to natural circulation until they'can get all the gas out.
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Fraley: Have they made any contingency plans in the event they lose their pressurizer; how would they pressurize the system?
Wright: They believe they can cool with natural circulation without the pressurizer.
Fraley:
I believe the gas will come out of solution and vapor bind the system if they let it depressurize.
Wright: Well let me ask Steve, maybe I misunderstood.
Wright: Yes, that's what they believe.
Fraley: They think they got the gas level down enough so that they will not vapor bind the system even if they had to?
Wright: That's true. But they are not going to take a chance en doing it.
They believe that they can do it if they had to.
Fraley:
I see, so they have no contir.gency plans if the pressurizer heaters fail, they would have to shift to natural circulation because then they can't run the primary pumps.
Wright: Yes, that's true.
F aley:
I see.
Wright: So I guess that is a contingency.
Fraley:
CK; that was a great concern to Carl Michelson. That sounds very strange to me.
If you have an opportunity, you might suggest that they reconsider that.
Wright:
OK.
Well, here's Dr. Lawreski, he can tell you; let him tell you the same thing.
Fraley:
Before Michelsen left, he was greatly concerned that if they lose their pressuriner heaters and the system depressurizes, the gas that's in the water will come out a solution and vapor bind the system and they won't be able to naturally circulate, and therefore; they should have some contingency plans to keep the system pressurized.
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Lawroski: 'Ihat's my understanding that they have those plans. We haven't been able to spend that much time with them.
Fraley:
CK, so even if the pressurizer heaters failed, they feel they can keep the system pressurized?.
Lawreski: That's my understanding from Vic. The question we pro-posed to them just a few minutes ago is, suppose you lose your pressurizer and you lose your primary coolant pumps, can you still tolerate that situation? They would prefer not to depressurize since that means a release to the outside, you know through the containment.
it would be a release of what is now estimated at about in the orde: of 10,000 cubic feet or a little less than that.
Fraley:
10,000 cubic feet of gas that is dissolved in the primary coolant?
Lawreski: That order of magnitude.
Fral?y:
That's at atmospheric pressure; 10,000 cubic feet.
Lawreski: Yes, about a liter of gas per kilo of solution of liquid.
Fraley:
And they think that would naturally circulate? OK.
They think they could keep the system pressurized somehow?
Lawreski: Yes.
l Fraley:
CK.
How is the pump behaving? Is it beginning to vibrate, l
rattle, and roll or is it still running nicely?
Lawreski: 'Ihey didn't lose the pump. 'Ibey lost the component cooling to it.
The pump itself is alright.
Fraley:
Have they reestablished the component cooling?
Lawroski: We don't know.
Fraley:
But the other pumps are being adequately cooled, are they?
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L Lawroski: Yes, the other pumps are alright.
Fraley:
How come they lost cooling to that one pump, do you know?
Lawroski:
No, we don't know.
I've been asking.
Fraley:
Do they know any more about the initial loss of feedwater, what caused it?
Lawreski:
I don't know. That's something the experts have to compute. We've tried to do this while listening to briefings here to learn what's the current status.
Let me make sure I pose the question, your question correctly.
Fraley:
Do they know any more about what caused the initial loss of main feedwater?
Lawreski: hhether or not it was the polisher or what?.
Fraley:
W'e are hearing different stories down here.
Lawroski: As they know it here, it was the polisher, from the ion exchanger that caused the trip.
Fraley:
W'e got a couple of other questions that you might get the answers to.
Did the operator know his primary system relief valve was open or not?
Lawroski: Yes, that's a question I wanted to ask.
W'e haven't even had a chance yet.
Fraley:
CK, fine, CK Steve, we are going to breakup here about 3:00 p.m., it might be useful if you gentlemen would report back at say, 2:00 p.m. or 2:30 p.m.
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