ML20214M470
| ML20214M470 | |
| Person / Time | |
|---|---|
| Issue date: | 09/03/1986 |
| From: | NRC COMMISSION (OCM) |
| To: | |
| References | |
| REF-10CFR9.7 NUDOCS 8609110130 | |
| Download: ML20214M470 (126) | |
Text
~0RIGINAL UNITED STATES OF AMERICA NUCLEAR REGULATORY COMMISSION In the matter of:
COMMISSION MEETING Briefing on IAEA Chernobyl Meeting (Public Meeting)
Docket No.
(
Location: Washington, D. C.
Date: Wednesday, September 3, 1986 Pages:
1 - 91 ANN RILEY & ASSOCIATES Court Reporters 1625 I St.,
N.W.
Suite 921 Washington, D.C.
20006 (202) 293-3950 8609110130 860903 PDR 10CFR PT9.7 PDR
.e 1
D I SCLA I MER 2
3 4
5 6
This is an unofficial transcript of a meeting of the 7
United States Nuclear Regulatory Commission held on S
9/03/86 In the Commission's office at 1717 H Street, 9
N.W.,
Washington, D.C.
The meeting was open to public 10 attendance and observation.
This transcript has not been 11 reviewed, corrected, or edited, and it may contain 12 inaccuracies.
13 The transcript is intended solely for general 14 informational purposes.
As provided by 10 CFR 9.103, it is 15 not part of the formal or informal record of decision of the 16 matters discussed.
Expressions of epinion in this transcript l
17 do not necessarily reflect final determination or beliefs.
No l
18 pleading or other paper may be filed with the Commission in l
19 any proceeding as the result of or addressed to any statement 20 or argument contained herein, except as the Commission may 21 authorire.
l 22 l
l 23 24 1
25
4
~ s' 1
1 UNITED STATES OF AMERICA 2
NUCLEAR REGULATORY COMMISSION 3
4 BRIEFING ON IAEA CHERNOBYL MEETING 5
6 PUBLIC MEETING 7
8 Nuclear Regulatory Commission 9
Room 1130 10 1717 "H" Street, N.W.
11 Washington, D.C.
12 13 Wednesday, September 3, 1986 14 15 The Commission met in open session, pursuant to 16 notice, at 2:04 o' clock p.m.,
LANDO W.
ZECH, Chairman of 17 the Commission, presiding.
18 COMMISSIONERS PRESENT:
19 LANDO W. ZECH, Chairman of the Commission 20 THOMAS M. ROBERTS, Member of the Commission 21 JAMES K. ASSELSTINE, Member of the Commission 22 FREDERICK M. BERNTHAL, Member of the Commission 23 KENNETH M. CARR, Member of the Commission 24 25
- - - ~
- -. =
o a
2 1
STAFF AND PRESENTERS SEATED AT COMMISSION TABLE:
2 S.
CHILI (
3 W.
PARLER 4
V. STELLO 5
H. DENTON 6
B. SHERON 7
T. SPEIS 8
F. CONGEL 9
10 11 12 13 14 15 4
16 17 4
18 19 20 21 22 j
23 24 25
3 1
PROCEEDINGS 2
CHAIRMAN ZECH:
Good afternoon, ladies and 3
gentlemen.
Commissioner Asselstine will join us shortly.
4 First of all, I would like to welcome Commissioner Carr to the 5
Nuclear Regulatory Commission.
6 This is an information briefing this afternoon, a 7
briefing by the staff on the accident at Chernobyl.
The 8
briefing is being video taped and regions I, III, IV and V are 9
listening via the telephone.
10 The staff has recently returned from Vienna where 11 the Soviet Union briefed the International Atomic Energy 12 Association on the accident.
13 This accident posed many lessons which are very 14 important to the safety of nuclear power operations throughout 15 the world.
Recognizing that the design of the Chernobyl plant 16 is different from that of any United States plant, we can 17 still learn some valuable lessons and retain and obtain 18 some valuable information from the accident at Chernobyl.
19 The United States is participating with other 20 nations of the world in preparing reports of the assessment of 21 the impact of the accident and we are here today to hear from 22 the staff about the new information that they have gained 23 recently and to be informed of a status report since our last 24 briefing.
25 The information includes the how and the what and
+
4 1
the why of the accident and I think it should be very valuable 2
information for all of us.
We will also hear of the progress 3
to date on the report the United States is preparing and the 4
prospects for completion of that effort.
5 Do any of my fellow commissioners have any opening 6
remarks?
7 (No response.]
8 CHAIRMAN ZECH:
Then I will turn the meeting over to 9
Mr. Stallo who will introduce his colleagues and then proceed.
10 MR. STELLO:
Thank you, Mr. Chairman.
I don't want 11 to take too long in the way of trying to describe where we are 12 going from here but I think you have raised a very important 13 point and that is the report that we have indicated that we 14 will have, a technical report on the Chernobyl accident.
15 Originally we had thought that that might take us 16 until December to finish but because of the amount of 17 information which was greater than we expected and the 18 forthrightness of the briefings by the Soviets and the 19 quality of the information we have, we believe that we will be 20 able to accelerate significantly that schedule of putting out 21 the report and that was to be followed shortly thereafter 22 with a study based on that report in terms of the actual 23 lessons that we think we can laarn from it and apply it to the 24 regulatory progra:n.
25 We do not want to commit to a specific date except
5 1
to say that.we expect to have it well in advance of the
{
2 projected date that we originally gave the commission which 3
was December, and we will do that.
4 Without taking a great deal of time, I think members 1
5 of the delegation from the NRC are here with me at the table 6
and I will let Mr. Denton start the briefing and he can 7
introduce at the appropriate time the other members of the 8
delegation to describe what we have learned from meeting with 9
the Soviets in Vienna.
10 CHAIRMAN ZECH:
Thank you. Mr. Denton, proceed.
11 MR. DENTON:
Thank you, Mr. Chairman.
It was a 12 very valuable conference.
It lasted five days.
We will try 13 to hit the highlights of the important things we have learned 14 and convey them to you.
15 I want to give an overview and talk a bit about how 16 the conference was organized and who attended and hit some of 17 the things that I thought were valuable.
Then I will ask 18 Brian Sheron on my left to describe the sequence of events 19 that led up to the accident, so he will deal with that aspect.
l 20 Themis Speis then will deal with what happened 21 actually during the accident, the core disassembly, fission 22 product source terms and some of the corrective actions that 23 the Soviets are taking.
24 Then Frank Congel will take it from there and 25 describe the off site radiation levels and dosimetry
6 1
measurements that have been made and some of the biomedical 2
aspects.
3 This conference really covered all aspects of 4
nuclear engineering from "A" to "Z" and feel free to interrupt 5
and we have a rather long presentation but we will try to move i
6 right along.
7 The Soviets had provided us a week before the 8
conference began the 300-page report and the 80-page summary 9
in Russian.
We had that translated as you know and provided 10 copies of that to the Commission and when we arrived there Friday, before we arrived they had translated it into English 11 12 so we did have the official IAEA approved version of the 13 report in English to begin with.
14 The delegation was very strong, I thought.
It was 15 led by Ambassador Kennedy.
In addition to we three from the 16 NRC here, we had a number of consultants with us.
We had 17 Dr. Richard Denning from Battelle Columbus who is an expert in 18 source term.
He happens to be in the audience today.
19 JWe had Professor Theofanous who is an expert in 20 steam explosions and related phenomenon from the University 21 of California and we had Professor Dick Wilson from Harvard, 22 you recall, who headed up the American Physical Society review 23 of source term.
So we had a technically very strong 24 delegation.
25 In addition to the NRC membership, there were
7 1
individuals there from the Department of Energy, from the 2
Environmental Protection Agency, from the Federal Emergency 3
Management Agency, from the Defense and Nuclear Agency, 4
Department of State and I have probably missed two or three 5
federal agencies.
But, I think, we had at the end 21 members 6
of the U.S. delegation.
7 In addition to the U.S. delegation, the IAEA had 8
invited a number of other organizations to send members.
So 9
they invited the American Nuclear Society.
They invited 10 INPO.
They invited EPRI.
They invited AIF and they had 11 invited similar organizations from other countries to attend.
12 So it was a large turnout.
Overall, the official
./
13 delegates to the conference was about 550 and I think that was 14 because that is all the room would hold.
Every country had 15 large similar delegations.
t 16 The three objectives of the conference were to one, 17 improve the level of reactor safety; second, increase the 18 understanding of the phenomena involved and third, to improve 19 international cocperation.
l 20 I would have to say that from our standpoint, all of i
21 those objectives were met in the meeting.
The Soviets were 22 l
very open, very candid.
I was surprised by the degree of 23 openness.
I had gone into the meeting thinking that we might 24 not get everything that we' expected and there might be 25 some things held back.
That was not the case at all.
8 1
The indicated a real desire for constructive 2
criticism.
We had two private meetings with the Soviets.
We 3
met once with the head of the delegation and then we met with 4
some of the technical staff.
In all of those they indicated a 5
desire to collaborate with the NRC under bilateral l
6 arrangements and to share reactor safety research and 7
experience.
8 So I think it opened the door that commissioner 9
Bernthal has been trying to open for some time and they did 10 mention the agreement that was signed in Moscow several weeks 11 ago as being the umbrella arrangement through which they would l
12 like to work in the future.
l 13 l
They took every opportunity, I think, to indicate a 14 willingness to work with U.S. agencies who are interested 15 in reactor safety and improve the safety of their plants.
16 Mr. Legasov, the head of their delegation, is a 17 physical chemist.
I found him to be unusually impressive.
He 18 had not worked in the RBMK reactor design.
Any questions ha 19 got, he didn't hedge.
I thought he gave a real objective view i
20 on why the plant was designed the way it was, how they got 21 into it.
22 He became an acadr.mician which is an honor in that 4
i 23 country at a very early age and it was encouraging to find 24 someone in the leadership position in their delegation with I
l 25 the attitude that he had toward reactor safety.
9 1
He gave a background on why they used this plant 2
which I think might be useful to spend just a moment on and 3
I think they gave it not being defensive but just so that the 4
conference could understand it.
5 He indicated that 25 years ago that they did not 6
have the capability to manufacture large pressure vessels or 7
steam generators, that they needed the energy, that 40-percent 8
of their rail transportation carried coal for electrical 9
burning stations, that they looked to the advantages and 10 disadvantages of this type of reactor.
11 He cited that it had a flexible fuel cycle, that it 12 could be easily constructed, that there be channel-by-channel 13 monitoring, that they replace fail fuel.
So he went through a 14 number of advantages that he thought the reactor possessed.
15 He also candidly said that we knew at the time it 16 had the positive void coefficient.
It was very sensitive to 17 reactivity disturbances, it had high thermal energy but at the 18 time 25 years ago when they made the balance, they figured 19 they had no alternative, they were going to pursue nuclear 20 power but to go to this type of design.
It was one they could 21 build and they felt they could ope. rate it safely.
22 So he spent some time describing those things.
I 23 think someone had asked me the question earlier, why did they I
24 go this route and he described that.
25 Then he showed a very interesting video tape about l
10 1
30 minutes long taken both outside and inside the plant. It 2
included pictures, video films, made inside many of the 3
crucial areas of the plant.
It showed the extent of damage 4
that had occurred.
5 That tape has been given to the IA2A and I imagine 6
one day it will be made available to us through that mechanism 7
and I am sure you will want to see it when it is available.
8 I would like to just hit an overview on the four 9
topics that are going to be covered by the other members of 10 the delegation.
11 Let me start with first the causes of the accident.
12 It is quite clear that the diract causes vere multiple 13 deliberate violations of procedure.
If you had to write 14 them down, you could say there were inadequate written i
15 procedures.
There was lack of proper authorization.
The I
16 procedures that they did use, these procedures had been I
{
17 reviewed by neither the safety review group nor the plant l
18 designers.
I 19 Mr. Legasov indicated it was because they only dealt 20 with the turbine generator and it was felt that they did not 21 involve safety significance.
22 Also, the operators violated procedures.
There were i
l 23 deliberate violations of procedures.
He talked about the 24 attitude of the operators.
This plant had the highest 25 capacity factor of' plants of this type in the Soviet Union.
l
11 1
4 He indicated that the operators may have lost all sense of 1
2 danger and that may have contributed to the attitude.
1 3
Then there were specific design features of the 4
plant.
There was a clear miss match between the control
)
system for this plant and the nuclear characteristics of the 5
6 core.
7 They had a slow acting control rod system, a low 8
reactivity worth and they set up a case where they had 9
extremely high worth potential reactivity in their fuel l
r i
10 channels upon voiding.
11 So that was all frankly admitted.
He said there was 12 a need for improved safety culture and that they were going to 13 try to achieve this through operator training, through 14 improved procedures from use of simulators and showed a lot of i
15 interest in meeting with the world at large on how that might i
16 be achieved.
1 j
17 They also talked about the need to have a design l
18 which mitigated operator errors and how this design obviously 19 j
depended on operators to keep the plant safe and that once it 1
20 got outside the bounds, the reactor was free to do what it J
j 21 pleased.
That was a term that he used.
l l
22 He also went on to say that they are committed to 23 further development of nuclear power.
He said they want to j
24 use reactors for district heating and also for combined 25 district heating and electricity production.
He said they
[
e
+--------,
4-
..y-a-ar,,--cu,eo,~,-,,w..w,%m,ymw,,--
-,wm,,,
_,__.%-,__m.-,,m.-
_e.%--_m_.y.
7-12 1
intend to also pursue breeder reactors.
2 So I guess with regard to the causes and sequence 3
and we will get to the details in a moment, it seems to me 4
that the causes are understood, that the general sequence is 5
clear but the details will have to be studied for a long time 6
and I~think will be of considerable interest to all the 7
specialists in the field.
4 8 '.
With regard to the accident itself, when they began 9
the experiment and the accident happened, they have been 10 forced to model what happened.
As you can guess, in any 11 reactor excursion as this one was, they have to rely on models 12 which have been developed elsewhere.
/
13 Their conclusion was that they had added 1.5 Beta in 14 two seconds to this reactor, Beta being the amount required to 15 pepromptcritical.
Shut down did not come from the control 16 rods.
The control rods were moving too slowly to be of any 17 real effect at shutting the reactor down.
It came from 18 destruction that occurred in the fuel.
Fuel fragmented during 19 this time and put enough energy and temperature into the fuel 20 channels to overheat and rupture the channels, lifted the top 21 plate on the reactor, sheared off the top of all the fuel 22 channels.
23 This eventually led then to the radioactive release, 24 the graphite fire.
They said about ten percent of the 25 graphite burned, some 250 tons.
The fire fighting that they
=_-
13 1
did sounded very impressive in view of the problem that they 2
had and that will be described a little later.
They had the 3
chief of the fire fighting service in the Soviet Union at this 4
meeting and he gave a very impressive presentation of the 5
challenge that was presented and the areas in which they 6
intend to improve their capability to handle such fires in the 7
future.
8 Three or four percent of the fuel was actually 9
expelled from the core and some scattered on site and some 10 away from the site.
11 It is not clear how to extrapolate what did occur 12 there to any other design but it is clear that the amount of 13 information to be learned from this accident does have immense r
14 value to trying to understand how to mitigate severe 15 accidents.
16 I wanted to mention a little bit about 17 decontamination and the emergency measures that they took.
It i
18 is clear they did an enormous amount of work and were very 19 candid about their limitations in responding to this 20 emergency.
21 They said that when they arrived on the scene on the 22 day of the accident the doses in Pripyat did not seem high 23 enough to warrant evacuation but during the evening the doses 24 began to go up and when they climbed above about 600 millirem 25 an hour, they decided to evacuate.
b 14 1
None of their emergency plans were adequate for the 2
circumstance.
They had to develop plans.to bring in the 3
buses to avoid the highly contaminated areas and that took 4
them approximately 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> to get their plan in place and 5
begin the evacuation.
6 They evacuated 10,000 cattle, for example.
They l
7 gave the people replacement clothing, just a massive effort 8
went on.
9 Since that time, they have been decontaminating 10 units 1 and 2.
They have been cleaning up unit 3.
They have 11 been trying to gain access to unit 4 to entomb it.
12 Their evacuation criteria were 45 rams and 75 rems;
(
13 that is 45 rems was the level at which they began to consider 14 evacuation and I understood 75 to be the level at which they 15 would absolutely require evacuation.
16 They said the one lesson they learned from this 17 was that there was an absolute need for single core dating 18 authority when it came to evacuation, that massive movements 19 of people and transportation that it was clear that there 20 should be one person in charge of that.
21 They indicated that they have to limit agricultural 22 use of the land for some time to come and that they are still 23 undertaking a number of large measures to avoid such things as 24 contaminated sediments in the water from moving downstream, 25 run-off from contaminating water and still have massive
15 1
programs in looking at determining the full extent of 2
contamination.
3 Finally, let me just touch on exposure.
They dealt 4
extensively with the distribution of the release, the 5
dosimetry involved, the characteristics of the release.
A lot 6
of attention was given to individual and collective doses.
7 Dr. Gus'kova gave an excellent presentation on the medical 8
treatment of the people who were acutely injured.
9 The source term was estimated from off site 10 monitoring to be about 50 megacuries not counting noble 11 gases.
I think we have talked often in the past about how 12 much got out and we will give you more details on that.
13 They did not have any weather data available from
(
14 the site.
The nearest site was Kiev.
There still is a 15 certain amount of uncertainty involved in trying to calculate 16 samples taken by helicopter and by airplane to determine 17 exactly what got out.
18 The medical description was very vivid.
She did 19 find some new very important facts that I think will be of 20 interest to the medical profession.
Skin does were very 21 important.
She said that surgical intervention turned out not 22 to be that effective.
i 23 We had representatives on the delegation, medical 24 doctors there, and they were quite complimentary of her 25 presentation.
o
- 16 1
They said that out no acute fatalities have occurred 2
or are expected off site.
We had talked about that point 3
early and they said that is still the case.
They gave out 4
large amounts of potassium iodide with no side effects.
That 5
is an issue we have talked about in the past and they said 6
that they have not determined any side effects over the time 7
since they gave them out.
8 There is clearly a great deal of information on 9
madical treatment that will be valuable and this whole are of 10 dosimetry and follow-up, I think, is going to be a very 11 fruitful area to pursue.
12 I think with that overview what I would propose to 13 do then is let Brian begin to walk you through what set up the 14 accident, go through the three speakers and then I would like 15 to come back and summarize the actions IAEA intends to take 16 from here and give some final remarks.
I j
17 CHAIRMAN ZECH:
Fine.
i 18 MR. DENTON:
Brian, why don't you proceed.
19 CHAIRMAN ZECH:
Thank you.
20 MR. SHERON:
May I have the second viewgraph?
21 (SLIDE.]
22 MR. SHERON:
As Harold told you, the cause of the l
23 accident was primarily two-fold.
One was human factor aspects 1
24 and the other was design aspects.
As he said, the test 25 procedures that were written up did violate certain Soviet I
~. '
17 1
safety regulations and the operators, in fact, violated these 2
test procedures that were written and also, the Soviets 3
believed that the operators had lost the sense of safety 4
vigilance with the reactor.
They became complacent because it 5
was good operationally.
6 This was compounded with the design aspects which 7
can be characterized as an apparent ease in which the safety 8
and protection systems could be overridden coupled with the 9
slow control rod insertion rate.
10 These rods took about 20 seconds to insert once the 11 signal was given and that was all compounded with the fact 12 that it had a positive reactivity void coefficient.
(
13 May I have the next slide, please?
14 (SLIDE.]
15 MR. SHERON:
Just to set the scenario on what they 16 were trying to do was they were planning to go into a 17 maintenance shutdown so they were planning to bring the plant 18 down at this time.
19 One of the things they wanted to test was if they 20 had tripped the reactor and lost off site power, how long i
21 could they keep emergency equipment powered by the rotating 22 inertia of the turbine generator system before they would have 23 to switch over to the diesels.
l 24 One of the characteristics of this plant is that you 25 have to keep water in it.
Otherwise, positive void
o
- 18 1
coefficient does play a very significant role.
So you want 2
to start the ECCS system fast and so forth.
You want to keep 3
feedwater pumps going.
4 They had run this test before in the plant 5
apparently with no problem.
One of the things they were 6
trying to do was they wanted to use a special generator 7
magnetic field regulator to try to keep the voltage at the bus 8
bars higher from the previous test.
9 On April 25th at 1:00 a.m. in the morning they 10 started to bring the power down.
11 May I have the next slide, please?
12
[ SLIDE. ]
I
(
13 MR. SHERON:
This is a viewgraph that the Soviets 14 passed out at the meeting of the power history and I will try l
15 to walk you along it very quickly with some of the key steps 16 that were taken.
17 As I said, on April 25th at 1:00 a.m. in the morning 18 they start the power descent.
About 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> later, at 1:00 19 in the afternoon, they reached 1,600 megawatts which is the 20 first plateau.
21 The load dispatcher, we understand, told them to 22 hold at that power and not to come down any more.
Apparently 23 there was a need for power at that time.
They held at that 24 power for about 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />.
At about 2:00 p.m. in the afternoon 25 while they were on the plateau, they did disconnect the ECCS
19 1
system.
2 This was a violation of their regulations.
- However, 3
we don't think it playe'd a very big role in the course of the 4
accident.
5 At about 11:10 in the evening, they started to 6
descend in power again.
The test procedure called for this 7
test to be performed at between 700 and 1,000 megawatts which 8
is around 25-percent power.
9 At 2:00 a.m. in the morning when they were 10 descending the operator switched over from local automatic i
11 control to a more, I think, we called it a global control of 12 the reactor.
They are allowed to do this but apparently at i
13 low power.
14 When they did this,there was a miss match in the set 15 point with respect to where the reactor was versus where the 16 set point was saying the reactor should be.
17 As a result the control system dragged the power 18 down much further than what they anticipated.
It actually 19 took it down to, I think, they said below 30 megawatts which 20 is below about one percent.
21 The operators in trying to regain control and bring 22 the power back up to where it was supposed to be for the test 23 had to pull rods out of the core because they got a big xenon 24 build-up because of the power reduction.
25 As they pulled the rods back, they were able to
~.
20 1
bring the power up and they were trying to level off at about 2
200 megawatts thermal.
The rods in order to get the. reactor 3
at this quasi-stable condition of 200 megawatts were pulled up j
4 beyond their normal limits.
5 When they pulled the rods beyond these limits, they l
6 did not have the reactivity margin that was required by their 7
specification so this was another violation.
So now they had 8
the rods pulled up.
9 MR. DENTON:
On the margin, maybe I should inject, 10 the margin is a number calculated by computer that is 11 expressed in the number of rods which are able to effectively 12 provide negative reactivity to shut the plant down.
Normally 6
~
13 the tech specs require 30 rods available and apparently if it
(
14 goes below 15, they said even Secretary Gorbachev was not 15 allowed to permit operation.
16 At this time, they said they had -- at the time the i
experiment was being conducted, they had six to eight rods.
17 4
18 That is going to play a very important role.
The 30 rods was 19 designed to provide an insertion rate of at least one Beta per 20 second of negative reactivity.
21 MR. SHERON:
At this time now the plant as I said 22 was in a quasi-stable mode.
The operator was trying to 23 control it.
These plants are difficult to control at low 24 power and keeping them in a stable condition.
25 j
In order to stabilize the plant, the operators had
0 21 1
-- I am sorry, before they started the stabilization, what 2
they had to do as part of the test procedure was to start two 3
additional reactor coolant pumps.
4 If you recall, this plant has eight pumps total, six 5
of which run all the time and two of which are in stand-by.
6 The way they intended to run the test was they would keep four 7
reactor coolant pumps running on off site power and four 8
reactor coolant pumps would.be running off of one of the 9
turbine generators and then when they started the test, they 10 would stop steam flow to that turbine and see how long the 11 generator would power those four reactor coolant pumps.
12 COMMISSIONER BERNTHAL:
Just back-up for a moment.
13 In all of the accounts that I have read and heard of these 14 tests, it w&c never made clear to me exactly why that was 15 considered a test so important.
Was it the lack of emergency 16 stand-by capability and a perceived need for that rather t
17 unusual mechanism for emergency power or what was the original 18 motivation for going to such great lengths to carry out that 19 experiment?
20 MR. SHERON:
My understanding is that these plants, 21 as I said before, are very dependent on having their 22 protection systems powered in order to protect again getting 23 the voids in the reactor.
For example, I think, their ECCS 24 analysis spoke to being able to get water into the plant in 25 three and a half seconds which is fairly quick.
+
- 22 1
So there appears to be a desire on their part to be 2
able to keep electricity to their emergency systems and I 3
believe the ones they were trying to power that were of 4
importance were the feedwater pumps and these reactor coolant 5
pumps.
You want to keep water going into that core and in a 6
force circulation mode as long as you can.
7 COMMISSIONER BERNTHAL:
But none of the other 8
emergency systems were capable of responding that quickly is 9
the point then, right?
I take it that is what you are saying?
10 MR. SHERON:
I am not sure.
I read in a report just 11 a little bit before I came here that this mode of operation 12 was actually credited in some of their safety analysis, at
(
13 least that is how I interpreted what I read.
14 COMMISSIONER BERNTHAL:
I see.
15 MR. SHERON:
Now whether they had actually performed 16 these tests to show that it could be done, I think that is 17 perhaps what they were trying to do.
18 In preparing for the test, they started two 19 additional reactor coolant pumps so now I had eight pumps 20 running.
This was also a violation of their regulations 21 apparently because it would set up vibrations, they said, in i
22 their feedwater system and I think it also violated some of 23 the flow characteristics.
I am not really sure.
24 I know it put too much flow through the core in the 25 sense that it may have pushed the pumps toward their run-out S
-n
-.n.,
,,. - - -, -. -. -,~.
a
23 1
condition closer to a violation of the net positive suction 2
head.
3 So they had eight pumps running now.
So they had 4
very high flow through the core.
They were at 200 megawatts 5
which was much lower, it was about less than ten percent 6
power, maybe seven percent.
So from a thermal hydraulic 7
condition, they had very little voiding in the core.
Now 8
obviously they were not generating a lot of steam because they 9
had very high flow, low power and they had the control rods 10 pulled all the way out much further than they were allowed.
11 This was leading the plant into an unstable type 12 condition in terms of trying to keep levels and everything
(
13 steady.
One of the things the operators did at this time was 14 that the separators, the steam separators, the steam drums 15 where the two-phase mixture goes in, the steam goes to the 16 turbine and the water, the condensate would go straight down 17 back to the pumps.
18 They regulate that level with the feedwater and one 19 of the problems they were having was trying to maintain that 20 level.
So in order not to get a reactor trip due to the 21 fluctuating pressure and level in that drum, they by-passed 22 that protection system which would have shut them down.
23 So now they had the steam drum oscillating in level 24 and so forth.
To compensate for that, they increased the 25 feedwater four times its normal flow rate.
So now put in a
4 24 1
lot of feedwater into this plant.
2 The other thing they did at this time and now I am 3
moving up right close to where you see the power go there, 4
the vertical there.
They disengaged the reactor trip that 5
would occur on a turbine trip and had they run this test and 6
left that on when they tripped the turbino, the reactor would 7
have scrammed immediately at that time.
d They disengaged this because they were afraid if the 9
test did not go well that they would have to run the test 10 over aga'in and these plants are difficult to start up once 11 they have been shut down.
So I think they wanted to retain 12 the capability that if the test did not go well, they could go l/
13 right back and run it again.
\\
14 Now they have set themselves up really for what 15 happened.
May I please go to the next slide?
16
[ SLIDE.]
17 MR. SHERON:
We can trace through and see what 18 happened.
They started the test and if you can see on this 19 viewgraph, the blue is the pump flow and as you can see, right 20 around about four divisions over from the left is where the 21 flow started to decrease.
That is when they started the test 22 and the pumps then would start to slowly coast down as the 23 generator frequency and voltage was decaying.
24 So now I have a situation where the flow is decaying 25 in the core very slowly.
At the same time about 30 seconds
~
25 1
prior to starting the test, the operators cut back the 2
feedwater flow from four times its normal rate to about 3
three-quarters of its normal rate.
4 So now I had less feedwater going in than even an 5
energy balance would call for for nominal conditions.
What 6
this led to is that about 30 seconds later, 20 seconds 7
later, which is the transit time from where the feedwater is 8
introduced up by the steam drum through the pump and into the 9
core, all of a sudden the temperature of the water entering 10 the core starts getting warmer because I have cut back 11 feedwater.
12 So now I just have saturated water coming from the
{
13 steam drum with very little feedwater mixing.
So I have 14 two conditions which are tending to put voiding into the 15 primary system which is decreasing flow and increasing inlet 16 temperature.
17 So at this time I start boiling.
I start generating 18 voids in the core.
19 COMMISSIONER ASSELSTINE:
Why did they cut back on 20 feedwater flow?
21 MR. SHERON:
Well, they were starting to over -- in 22 other words, they had four times the feedwater flow that is 23 normal and this would tend to fill the steam drum if they 24 didn't cut back on it.
So they were kind of just pulsing the 25 feedwater trying to keep the level at some operationally
26 1
acceptable level.
2 COMMISSIONER BERNTHAL:
What is the normal void?
3 What was the normal voiding?
4 MR. SHERON:
All right.
At full power the quality 5
at the exit of the core is about 14-percent and this 1
I 6
corresponds to a voiding of anywhere up to 80 or 90 percent 7
void fraction.
8 COMMISSIONER BERNTHAL:
Is that right?
9 MR. CONGEL:
At the exit.
10 MR. SHERON:
This is probably an annual flow so it 11 still keeps liquid on the wall.
But in this condition they 12 had very little voiding.
[~ 3 13 So now I am starting to put voids into the core when 14 I start the test.
15 With the condition that the rods are all pulled out 16 of the core, the void reactivity coefficient is a function of 17 that and they told us that the void reactivity coefficient 18 instead of being two times ten to the minus four was three 19 times ten to the minus four or a factor of 50-percent higher.
20 So it was even more reactive.
21 On top of that to compound it, when I have a system 22 that has very few voids in it as I start to produce steam in 23 it, the voiding increases much more rapidly than it would say 24 at full power.
It is much more sensitive.
25 So what I had as a situation is as I coasted down
27 1
with the pumps, the inlet temperature increasing, I start to 2
put in a big shot of r'eactivity into the core.
3 CHAIRMAN ZECH:
This is the key condition resulting 4
from the positive voiding reaction in this design?
5 MR. SHERON:
Yes.
6 CHAIRMAN ZECH:
Isn't that correct?
So in other 7
words, what you are telling us is if they had a negative 8
voiding condition as our plants have, what would be the 9
effect?
10 MR. SHERON:
It would have tended to shut the 11 reactor down.
12 CHAIRMAN ZECH:
Right, instead of having it go up in
[
13 power, it would have gone down in power.
14 MR. SHERON:
Correct.
15 CHAIRMAN ZECH:
So this is a very key element of the 16 reactor design.
17 MR. SHERON:
Yes.
18 CHAIRMAN 'Z"CH:
And you are about to tell us exactly 19 what happened bece}use of the positive void condition, is that 20 right?
21 MR. SHERON:
Yes.
22 CHAIRMAN ZECH:
All right.
Go ahead.
23 MR. SHERON:
Anyway, as you can see these curves 24 were calculations that were performed by the Soviets on a 25 computer model that they had developed for this.
+ -
28 1
The pink curve coming from the left is the power, 2
neutron power, in percent and as you can see right around the 3
middle at one hour, 23 minutes and 40 seconds, it starts to 4
rise.
This is how they calculated the power would increase 5
due to that reactivity insertion.
6 It goes off scale at about 120 percent and then 7
pick:s up again on a different scale which Dr. Speis will 8
describe again which is curve "D" which you have there.
9 As Harold said, they said they inserted something 10 like 1.5 Beta, I believe it was, in two seconds.
We did some 11 very crude hand calculations while we were in Vienna and came 1
12 up with numbers on that order of magnitude.
So we felt i
13 comfortable that based on this information that this seemed to 14 be a very plausible explanation of what happened.
15 So if there are no other questions, I guess 16 Dr. Speis will proceed.
17 MR. SPEIS:
I would like to stand up and just show 18 you on this viewgraph here.
19 CHAIRMAN ZECH:
Sure.
Go ahead.
20 MR. SPEIS:
Dr. Sheron described the flow decay at 21 this point in time.
The flow decay came as a result of the 22 decay of the inertia of the turbine.
We should have mentioned 23 that the valve which puts steam into the turbine was closed at 24 the beginning of the experiment.
That is how the experiment 25 was initiated.
29 1
So you see that the flow begins to decay and somehow 2
this is the power rise and by the way, this is a calculation 3
done by the Soviets.
So you see a slow rise in power and as 4
it gets higher, at this point in time as Brian said the power 5
is 100 percent of nominal.
6 CHAIRMAN ZECH:
Excuse me.
These are not actual 7
tracings of what happened?
8 MR. SPEIS:
No.
9 CHAIRMAN ZECH:
These are calculations?
10 MR. SPEIS:
This is a calculation model.
The only 11 thing that is actual here is this flow decay.
This point here 12 is an experimental point.
I think this one here, too, Frank?
13 MR. SHERON:
Only the letters with the circle around j
14 them correspond to an actual data point.
15 CHAIRMAN ZECH:
I see.
The only data points are the 16 those with the circles around them.
17 MR. SHERON:
Yes, sir.
18 MR. SPEIS:
So this one is a calculation model.
The 19 Soviets put a model together trying to understand what 20 happened.
21 CHAIRMAN ZECH:
Right.
Thank you.
22 MR. SPEIS:
So as the reactor is voiding and because 23 of the positive void coefficient, the power basically takes 24 off and at this point as I said, the power is 120-percent of 25 normal.
Instead of 3,200 megawatt thermal, it is 38.
Now it
30 1
is beginning to take off so fast out and you have to come down 2
here where it continues.
It is a different scale.
3 At this point in time, at this point here, the power 4
is 120 times nominal, 120 times 3,200.
5 COMMISSIONER BERNTHAL:
What is the time scale on 6
the axis?
7 MR. SHERON:
One second per division.
8 MR. SPEIS:
One second.
9 COMMISSIONER BERNTHAL:
One second per division?
10 MR. SHERON:
Yes.
11 MR. SPEIS:
So the point up here is 480 times the 12 normal power.
Now the Soviets based on this module,'they have
/
13 said that they estimate that the energy input into the fuel at 14 this point was about 300 or 350 calories per gram.
Now that 15 energy is enough to disperse the fuel and break the fuel beam, 16 disperse the fuel into the fuel channels and then we will have 17 according to their theoretical assessment, is that the 18 dispersed fuel interacted with coolant and the high pressures 19 that were generated led to the bursting of the tubes 20 themselves and the pressure that was generated from that was 21 enough to create the havoc that was created.
l 22 Mr. Denton already said that they think they 4
23 introduced 1.5 Beta in a p.riod of two seconds.
I think that 24 number probably is a net reactivity based on the voids.
I 25 don't think that number takes into account the negative n.
31 I
1 feedbacks that possibly exist in this system.
~
2 Anyhow, you don't have to go higher prompt critical 3
or super critical to lead to the situation that happened 4
there.
You also need a minor increase above critical to get 5
to this stage.
6 COMMISSIONER BERNTHAL:
Three hundred calories per 7
gram is kind of an antiseptic technical term.
Have you worked 8
out the total energy release in some units that are commonly 9
understood, comparative units of some kind?
10 MR. SPIIS:
We have translated this to megawatt 11 seconds or mega jewels but we have taken this curve that you 12 see there, the power profile, and integrated --
13 COMMISSIONER BERNTHAL:
I was thinking more in terms s
l 14 of pounds of TNT.
15 MR. SPEIS:
We haven't done it but we will do it.
16 COMMISSIONER BERNTHAL:-
It would be an interesting l
17 thing to know.
18 MR. SPEIS:
Again, the Soviets have said that it 19 took 300 calories per gram.
Our evaluation of this if we 20 integrate the whole curve, the lower curve, we get 600 and as 21 I said, we get 300 only up to the center, up to this point 22 here but if you integrate up to here, you get about 600 23 calories per gram based on the total fuel.
l 24 But you have to realize that some of the fuel, of l
25 course, is running cold and only part of the fuel reached the 1
(
o
- 32 1
high temperatures that were required to fail.
2 This took place in the lower one-third part of the 3
core.
The reactor possibly shut down as a result of the 4
homogenization that took place.
I have a picture later on 5
that you will see, the forces.
There is no heterogeneous 6
reactor there any more at least at the lower part of the 7
reactor.
8 The large part of the graphite was expelled.
So the 9
supposition is that that was the process that led to the 10 critical shut down of the reactor.
11 MR. STELLO:
Commissioner Bernthal, let me 12 interj ect.
To help you understand the numbers, as I recall
, ('
13 melting of fuel is about 260 calories per gram and up in the 14 600 or 700 calories per gram, you are talking about literally 15 vaporizing the fuel so that the amount of energy available 16 then is very, very large in terms of transfer of that energy 17 to anything.
18 COMMISSIONER BERNTHAL:
You said the integral energy
)
19 deposition over that curve is how much?
I 20 MR. SPEIS:
Six hundred calories per gram.
)
21 COMMISSIONER BERNTHAL:
It is 600?
22 MR. SPEIS:
The first peak.
23 COMMISSIONER BERNTHAL:
Oh, the first peak.
24 MR. SPEIS:
Just the first, yes.
I am not so sure 25 that we should be paying too much attention on the second one yr,_., _ _, _ _, _ _,
-r
-.--_---,-.-m.
33 1
because this is really a calculation model and possibly what 2
happened after that, the interaction that took place in the 3
channel led to additional voiding and the model was concocted 4
in such a way that the excursion took off more.
5 I think it would speculation beyond the first area 6
there that I mentioned.
But in any event, the fuel failed.
7 The interaction took place.
The pressures were generated.
8 The upper slab was lifted.
It weighs about 1,000 tons.
Based 9
on calculations that have been done both last week and since 10 we came back, it takes about two atmospheres to lift this slab 11 of 1,000 tons.
12 It takes much more to fail the tubes.
You know, you
(
13 have 2,000 pressure tubes up there that as the slab moves, 14 they have to be pushed out of the way.
It takes much more 15 than -- it takes probably a ten or so atmospheres to fail 16 them.
17 But that assumes that they are in good shape, that 18 they have not been affected because of any temperature 19 effects during this process.
20 The consensus at the conference was that it possibly 21 it was a prompt reactivity excursion but even if it wasn't a 22 prompt, the process would have taken roughly the same route.
23 So as Harold said, you know, there are many details that 24 probably theoreticians will be working for the next five or 25 ten years to understand but the general picture, you know, is
34 1
robust as the chairman of the conference pointed out of what 2
basically happened.
3 Let's go to the next viewgraph, please.
4
[ SLIDE.)
5 MR. SPEIS:
Having discussed the disassembly and the 6
energetics, I would like to say a few things about the source 7
term that was released.
The release estimates were based on 8
measurements done by helicopter, that is the air borne 9
radionuclides and, of course, the measurements done on the 10 ground from the ground contamination.
11 The estimated release fractions appear to be 12 consistent with their understanding of the scenario and it is
( ~
13 consistent also with measurements that have been made in other 14 countries.
15 The accident is divided into four states of release 16 and the next viewgraph will show that graphically.
The next 17 viewgraph, please.
i 18
[ SLIDE.]
19 MR. SPEIS:
This picture shows the release as a 20 function of time starting with the day of the accident.
You 21 see the first one is the earlier release that was due to the l
22 excursion.
It is basically based on some vaporization and j
23 then the destruction of the fuel was carried by the plume and 24 deposited.
So a large release took place during that first 25 part.
35 1
The second part, you see a kind of decay that lasts 2
for about three or four days and if you recall during that 3
time, the Soviets dumped a large number of material on top of 4
the destroyed core.
5 First they put about 40 tons of boron carbide.
One 6
of the objectives of that was to make sure that the chain 7
reaction stops to make sure that indeed it stops in case there 8
was any questions that some part of the core could still go 9
critical.
10 As Harold said, thin reactor is very large and it is 11 really made up of a large number of sub-critical -- or 12 critical cores.
Many parts of the core itself can become
( ~
13 critical on its own.
14 They dropped about 800 tons of Dolomite.
Dolomite 15 can produce carbon dioxide and they thought that maybe the 16 carbon dioxide can be used as a fire extinguisher.
They put 17 about 2,400 tons of lead and the reason for that was to hold 18 down the temperature.
It is a heat absorber as it melts.
19 Also, they dropped about 1,800 tons of clay and sand i
20 for filtering purposes.
21 So between all these materials, the activity was 22 decreased during the four or five days.
23 Later on you had another stage where the activity 24 started going up and that can be associated with the core 25 heat-up.
During that time, the core possibly was insulated i
J
36 1
and decay heat led to heat-up.
Some of the openings were 2
plugged and you had no natural convection so during that time, 3
the activity as increased.
4 Then finally on the 18th day, there is a sharp 5
decrease and I think that can be associated with the cooling 6
of the core.
At that time they were introducing liquid 7
nitrogen and the core was finally being cooled and also some 8
of the oxidation processes, you know, were being terminated at 9
that time.
10 COMMISSIONER BERNTHAL:
Themis, one of the questions 11 that persisted for some time and I assume was resolved now, 12 was the question of whether there was an additional 13 oriticality at some point.
I had early suggestions from
[
14 remote measurements that there had been a re-criticality of 15 some kind around the 9th, in fact.
Has that issue ever been 16 cleared up?
17 MR. SPEIS:
It came up at the conference and the 18 Soviets said their assessment is that there is no sudden 19 criticality.
Earlier when I described the evolution of the 20 accident, I should have said that there was a second explosion 21 two or three seconds following the first one.
22 In the minds of the Soviets as well as other people, 23 it is associated with a potential hydrogen explosion.
Some 24 people said maybe it was a re-criticality but the Soviets and i
25 othe;s are discounting that possibility.
l
37 1
MR. DENTON:
You had asked earlier about the spent 2
fuel pool and they indicated that the spent fuel pool was not 3
involved in the accident.
4 MR. SPEIS:
Another thing that was happening at 5
phase one here, the UO-2 was changing into U-3/O-8 which is a 6
compound that is earlier to fragment so that is why you have a 7
large amount of mechanical release.
8 Another thing that I should have mentioned, at the 9
second stage where the activity is decreased, at that stage 10 you have quite a bit of heavy actinides being released.
As 11 you might have read from the report, they measured something 12 like between three to four percent of actinides, plutonium f
13 and later on, I will show you the table.
14 Again, that would be associated with the change from 15 UO-2 to U-3/O-8.
So there are a lot of details that still 16 have to be understood in terms of temperatures instead of 17 compounds that ware produced as a result of the processes that 18 were going on.
So this area again will be very fruitful for 19 chemists and others for many years to come.
20 COMMISSIONER ASSELSTINE:
Themis, the first' stage, 21 how rapidly did that release occur?
22 MR. SPEIS:
This was expelled following --
23 COMMISSIONER ASSELSTINE:
Seconds or minutes?
24 MR. SPEIS:
It was very, very fast, yes, in the 25 first minutes, yes.
38 l
1 The next viewgraph, please.
2
[ SLIDE.]
3 MR. SPEIS:
This is again'a table from their
'j 4
report.
This lists some of the more important nuclides.
As
\\
5 you see the nobel cases, 100-percentf, you see Ycdine 131, 6
20-percent was used.
You see ces am 137, for example, 7
13-percent and down towards the end of the table you see the 8
actinides that I said earlier, the plutoniums that go up to 9
the three percent. numbers.
10 The next viewgraph, please.
11
[ SLIDE.]
(
12 MR. SPNIS:
I have summarized here the estimates
+
f 13 made by the Soviets.
Harold already mentioned that the total 14 radioactivity was approximated to be 50 million curies with
- p..,
4 x s 15 another 50 million megacuries of noble cases. 'The, average I
q e
',16 release fraction excluding noble gases again was 3;5*)ercent.
ce 17 That is fdom the total core.
I, f'
N, 18 AgainjeI have listed the key ones, the noble 5ases,
' '<1 s.3
- q i
19 Iodine, 20 percent; Tellurium, 10-percenti; Cesium, h :'
st
/,
\\-
20 13-percent.
I think I have discussed already the. phases of 21 the accident so we can, move to the'next viewgraph,.ple se.
.g, 1;'
22
[ SLIDE.]
s
,j 1
3 23 COMMISSIONER ASSELSTINE:
Themis, if you were to'put \\
d'
]
' y
\\,
24 this in WASH 1400 tene.inology, what does this translate. this
'4' of n to infierms'o'f release categories, PWR-3?
25 i
H f ]
\\
)
\\,
s
\\
-__.,,_.____.,,---..---,hL c--
~;
l-1--
U-------'-
I-39 1
MR. SPEIS:
PWR, somewhere between two and three, I 2
guess, except with the exception of the actinides where we get 3
much lower numbers because we don't have scenarios like the l-4 fire and high plume and the thing that happened at Chernobyl.
5 There we get much less than one percent for the actinides.
V 6'
P COMMISSIONER ASSELSTINE:
all right.
r 7
MR. SPEIS:
The next viewgraph, please.
r 8
[ SLIDE.]
'E MR. SPEIS:
I would like to go to another subject
)
10 now and say a few things about fire fighting.
This 11 presentation was made by General Kimstach.
He is the chief 12 fire fighter of the Soviet Union and apparently he was I(
13 one of the first ones to arrive on the scene to participate in 14 the process of fighting the fire.
Many fires broke out during the accident.
They say 15 16 as many as in 30 h2 aces and, of course, that was due to the
~
i(<
i7 high temperature fragments that were expelled from the core
'l la and it heated the roof of the reactor building, the machine 19 hole and other areas.
Cs 2O(
They told us that three teams went to the site V,
21 immediately.
The fires were localized to roofs by 2:30 N ~l a
22.
a.m. and basically, the fires were quenched by 5:00 a.m.
The i
fa A
+,
P' 23T' most important objective was to prevent the spread of the fire
)
- v 2
yto unit 3 along the top of the machine hole from unit 4.
g 4:3 ', 25?
Basically they used water extinguishing material.
,D,
.,y
.'(
%w'
\\ f
40 1
The fires were merely on the surface and a very extensive 2
presentation was given by General Kimstach on the lessons that 3
they learned.
4 Harold already mentioned that the IAEA would like to 5
have a symposium or some type of conference in this area to 6
get the world together to discuss the lessons that have been 7
learned from the experience at Chernobyl.
Some of the things 8
that were mentioned was that there is a need for more clear 9
cut rules and standards, improved fire fighting equipment and, 10 of course, one of the key areas was the special problems that 11 were posed by the burning of graphite.
12 The next viewgraph, please.
13
[ SLIDE.]
14 MR. SPEIS:
This is a view of the core.
It is 15 unfortunate that it didn't come very clear.
When the video is i
16 provided to us from the IAEA, you will see this.
This is a 17 picture of the bottom of the core.
It is just a mess.
It is 18 kind of semi-homogenized.
Some of the circles that you see 19 there are -- what do you call them, Brian?
20 MR. SHERON:
Instrumentations.
21 MR. SPEIS:
Instrumentation that they are trying to 22 measure the heat, the velocity and parameters such as this 23 which are very important in deciding how to build the 24 sarcophagus which I will discuss later on.
25 Next slide, please.
I
~
41 1
(SLIDE.]
2 MR. SPEIS:. This is from the top.
This is with the 3
helicopter.
One of the big things, one the most important 4
things that they have been doing is deciding what to do with 5
this mess that was left behind from this accident.
They have 6
decided to build a sarcophagus and enclose the destroyed 7
reactor.
They have been doing quite a bit of work trying to 8
find out how to design it, what type of materials to use in 9
building it.
10 The first thing that they had to do was to decide or 11 to make an assessment where the fuel was.
They did this by 12 the process of elimination.
They finally concluded that most 13 of the fuel was in the reactor room.
14 Basically, they will be building or constructing a 15 concrete wall building around unit 4 to make sure that the 16 radioactivity is confined.
Also, an inner concrete partition 17 wall in the turbine hall will be built to separate the third 18 from the fourth unit.
19 Also, they will put a metal partition to separate 20 unit 2 from unit 3.
A protective roof also will cover the 21 turbine hall and the central hall and other reactor rooms will j
22 be completely sealed off.
Also, in addition to that, concrete 23 will be poured over debris in some areas inside the reactor 24 building itself.
25 As I said, they have undertaken an extensive
= -
42 1
experimental program to decide what are the proper materials 2
to select.
They have been doing a large number of experiments 3
involving molten core with different types of concrete.
They 4
finally selected a concrete that contains magnesium oxide.
5 They call it a refractory concrete.
6 Some of you may recall that that is the type of 7
material that we selected in the FNP plant.
8 The next viewgraph, please.
9 (SLIDE.]
10 MR. SPEIS:.The next thing that they considered was 11 whether to make it a closed or an open system and they looked 12 at the pluses and the minuses and they decided that they 13
(:
needed to have an open system because it permits a simplified 14 control of hydrogen and also easy monitoring and maintenance.
15 So what basically they do, they have this building 16 and they push air in and the air comes outside so it is not a 17 totally isolated building.
18 A negative pressure differential will be maintained 19 between the building and the environment.
They also said that 20 they expect that units 1 and 2 will rssune operation in 1986 21 but unit 3 they Jay will undergo a thorough safety review 22 before resuming operation.
23 Also, I think they mentioned that the building of 24 the sarcophagus is very closely tied to the operation of 25 unit 3.
So I don't think we are going to see the operation of
43 1
unit 3 until they have solved the problems associated with the 2
unit 4 reactor.
3 COMMISSIONER BERNTHAL:
I take it they still expect 4
considerable hydrogen generation.
5 MR. SPEIS:
Yes, dehydration of the concrete and 6
maybe there are other materials there.
7 COMMISSIONER BERNTHAL:
Is a question of heat 8
transfer out of the entombed core material pretty well 9
answered now?
10 MR. SPEIS:
There will be an act;t. system to take 11 of this now.
It is very interesting to hear them describe 12 this problem that they had to put into operation in the last 13 three or four months.
It reminds us of some of the programs 14 we had in place for the last ten years, you know, in some of 15 our laboratories.
They had to go on a crash basis to solve 16 some of the problems.
They have to entomb the reactor.
17 (SLIDE.]
18 MR. SPEIS:
The next viewgraph shows a pictorial of 19 what I was just saying earlier.
This is unit 4 and unit 3 is 20 on the other side.
21 I would like to spend the next few minutes 22 discussing some of the modifications that they have proposed 23 in order to enhance the safety of their RBMK-1000 reactors.
24 The next viewgraph, please.
25
[ SLIDE.]
44 1
MR. SPEIS:
Basically they will -- one of the first 2
things that they are doing, they will be permanently inserting 3
in the core -- let's have the next viewgraph, please, so we 4
can see pictorially what they are doing while I am talking.
5
[ SLIDE.]
6 MR. SPEIS:
The control rods will be permanently 7
inserted in the core to a depth of 1.2 meters and this measure 8
will increase the speed of introducing the necessary negative 9
reactivity in the core.
If you recall during the experiment, 10 this requirement was violated and the rods went beyond that 11 and, of course, it took a long time to come in when they han 12 to come in.
13 The next thing that they will do -- may I have the 14 next viewgraph, please?
15
[ SLIDE.]
16 MR. SPEIS:
They will introduce 80 rods into the s
17 core.
At the present time, they have 50.
This will further 18 reduce the positive void coefficient, they said, I think, by a 19 factor of two.
This is a temporary measure.
20 Let's go to the next viewgraph, please.
21
[ SLIDE.]
22 MR. SPEIS:
Until they change the enrichment from 23 2.0 to 2.4-percent, this will substantially decrease the 24 positive void coefficient and between this action here, the 25 increase in enrichment from 2.0 to 2.4-percent, and the
45 1
introduction of insertion of some additional absorbers, it 2
will assure that the positive coefficient is less than one 3
Beta.
It will still be positive but it will be less than one 4
Beta.
5 They talk about some additional things.
For 6
example, they will have --
7 COMMISSIONER BERNTHAL:
How long is it going to be 8
in the future?
9 MR. SPEIS:
The first two things are done now.
The 10 level of 1.2 meters and the introduction of 80 rods but the 11 enrichment, it will take a while.
I understand that they have 12 been doing experiments on the behavior of enriched fuel to 13 2.4-percent so I would probably think about a year or two 14 years.
15 MR. DENTON:
I think tleir goal was the end of next 16 year or something like that for the fuel enrichment change.
17 COMMISSIONER BERNTHAL:
I see.
18 MR. SPEIS:
They will add additional indicators in 19 the primary coolant pumps to monitor cavitation and again, 20 this is an indication that possibly during the performance of 21 the experiment in addition, the voiding was further augmented 22 by cavitation.
23 This is an area that in our private meeting, they 24 are not sure, you know, they had to do more studies but it is 25 a concern and they will do this.
46 1
Also, they will introduce the automatic calculation 2
of reactivity so that when they exceed a certain excess 1
3 reactivity, they will shut the reactor done.
4 Also, Mr. Denton mentioned that they are undertaking 5
organizational steps to enforce technological discipline and 6
to improve the quality of operations.
7 The other thing that they said they were studying is 8
they are evaluating di9 arse absorbers such as liquid, gas or 9
solid for future use, fast-acting absorbers, maybe something 10 similar to what we have in our BWR's, the stand-by liquid 11 control systems.
12 That completes my presentation.
~
13 CHAIRMAN ZECH:
Thank you very much.
14 MR. CONGEL:
May I have the next viewgraph, please?
15
[ SLIDE. ]
16 MR. CONGEL:
I would f'irst like to discuss a little 17 bit about the manner in which the plume moved during the first 18 four or five days into the accident.
19 By virtue of the fact of the direction that the 20 winds were taking the firs't day, the town of Pripyat was 21 spared some of the direct radioactivity that resulted early on 22 in the accident.
In fact, the first day the wind was 23 primarily to the north and the west as shown on the slide.
24 As the beginning of the second day dawnad and went 25 into the third day, the winds were blowing pretty much through
47 1
the city of Pripyat and as you will see later on in my
/
2 discussion, I will discuss some of the dose rates that the 3
people there experienced when that wind took a change.
4 COMMISSIONER ASSELSTINE:
Frank, what were the wind 5
speeds approximately?
6 MR. CONGEL:
I was going to mention they had wind speeds 'that varied substantially depending on the altitude at 7
8 which the material reached.
They did confirm our initial 9
appraisal that the energy of the release itself had to bring 10 the material high into the atmosphere like above 1,000 meters 11 in order for it to be transported to the Scandinavian 12 countries.
13 In fact, they did do measurements directly in the 14 plume with helicopters and airplanes that were equipped with i
15 gamma and beta sensitive devices.
But the winds did vary.
16 They had hot spots and I am getting ahead a little bit, but 17 they did find some hot spots, that is, extra activity on tha 18 ground that resulted from localized rainfall.
19 There was a remark made but not expanded upon where 20 they talked about doing some seeding of clouds to prevent rain 21 so that they could prevent the material from coming down 22 rapidly out of the cloud.
23 Staying up in the atmosphere, of course, allowed it 24 a longer time to both decay and to disperse.
25 on the fourth day as shown here, the plume did move
48 1
southward toward the town or village or city, excuse me, of 2
Kiev.
The measurements that were made directly in the plume 3
indicated dose rates on the order of one R per hour as far as 4
five to ten kilometers from the site and they did look for and 5
found both fission products and some activation products.
6 There were several questions asked during the 7
session about specific data on meteorological parameters 8
during the accident and the Soviets indicated that their 9
primary data base was from Kiev.
Apparently they had the best 10 monitoring data there.
11 The questions regarding monitoring data around the 12 site indicated that they had the same monitors around the site 13 that existed generally in the European region for predicting f
s 14 weather but not the degree of detail that was found in Kiev.
15 Could I hava the next slide, please?
16
[ SLIDE.)
17 MR. CONGEL:
I want to talk initially about the 18 doses that the individual workers experienced.
Clearly those 19 were the people that got the highest doses and, in fact, the 20 ones that showed both ill effects and also the ones that in 21 some cases died.
22 The first victims were as one would expect the fire 23 fighters and also some of the or a couple of the staff people 24 who went up to the deck to examine what had happened when they 25 heard the first explosions.
49 1
The first victim that died was very early on in the 2
accident, like 6:00 on that first morning, and it was from the i
3 physical trauma, the burns associated with the fire.
There 4
was another worker who was lost that they had not recovered 5
because of the allegedly where he was working, the area 6
apparently collapsed.
7 Twelve hours into the accident, it was recognized 8
that there was a substantial amount of radioactivity or 9
radioactive doses delivered to the workers and the Soviets 10 moved in a very comprehensive force of medical people to both 11 examine and treat the injured workers.
12 The people who were most severely impacted by the g
doses were hospitalized in a special center in Moscow.
Of the 13 14 129 that were hospitalized in Moscow, the 84 were diagnosed as 15 experiencing the symptoms associated with acute radiation 16 illness.
17 Some of the others were observed for an extended 18 period of time because they chowed preliminary indications 19 that they had received substantial doses but not those that 20 were immediately life threatening.
21 Could I have the next slide, please?
22
[ SLIDE.]
23 MR. CONGEL:
When all of the examinations and l
24 evaluations had been carried out, they indicated that there l
25 were a total of 203 persons hospitalized and as I said t
50 1
earlier, this was totally from the group of workers on the 2
site and there were no members of the general public included.
3 They were examined for any evidence of receiving 4
neutron exposure by virtue of their proximity to the reactor 5
and there was no evidence of neutron exposure.
4 6
The victims were examined and in the cases of the 7
ones that had died, autopsies indicated that there were 8
substantial amounts of cesium and plutonium in the lungs.
The 9.
hospitalized people all fit into a dose group of receiving 10 greater than 100 rem.
Thirty-five of those people exceeded 11 400 rem and the estimated maximum dose that people received 12 were in the 1,200 to 1,600 rem range.
13 The estimations of these doses were discussed by i
14 Dr. Gus'kova, the physician who was in charge of treating 15 these people in Moscow.
They had to use special techniques in 16 order to estimate these doses because many of them were 17 experiencing physical trauma from the fire as well as 18 radiation doses.
19 In addition, a number of the people had rather 20 severe skin doses from Beta activity and therefore, 21 experienced skin burns.
The people were observed on a 22 symptomatic basis and treated on that basis in the cases where 23 they were not able to predict the dose in rads that they had 24 received.
25 COMMISSIONER CARR:
Did they have badges on anybody?
51 1
MR. CONGEL:
Not to my knowledge.
They question was 2
asked.
I believe in the heat of the emergency the people were 3
just sent down.
4 COMMISSIONER CARR:
The workers who were there, none-5 of them had badges?
1 6
MR. CONGEL:
The ones that were in this injured j
I 7
group were the fire fighters and they were not badged.
In 8
terms of the workers who were on the site at the time or in 9
the range, there was no data indicated at this meeting 10 regarding the reading from those badges.
11 COMMISSIONER BERNTHAL:
They may be saturated 12 readings anyway for doses at that level.
I don't know what 13 normal badges are capable of reading.
14 MR. CONGEL:
Perhaps that was the case.
I believe 15 that because they were in such a hostile environment, that the important thing was to see the extent of the injuries and 16 17 physicians were treating the injuries.
18 There was a discussion and I will being an aside up 19 right now between some of the physicians who were attending 20 the meeting about the usefulness of knowing the actual dose 21 that people received.
The consensus turned out that because 22 of the wide ranges of individual responses even to the same 23 dose range, the physicians are really forced into treating the 24 symptoms as they appear and it is of secondary interest to 25 really know what caused those symptoms.
1
4 52 1
CHAIRMAN ZECH:
But it would be important to know 2
whether the workers at the site had badges at all and were j
3 they wearing them.
4 MR. CONGEL:
That is correct.
The question was 5
addressed but there was no real information provided.
6 CHAIRMAN ZECH:
Perhaps we can find out later.
7 MR. CONGEL:
There was a substantial amount of 8
information presented regarding the estimated doses to the 9
public in the 30-kilometer zone surrounding the plant.
10 There was enough information so that and in a way it 4
11 was sometimes difficult to sort out, I have over the next few 12 slides some summary slides that were presented at the meeting 13
),
and what I will attempt to do is to give you a picture of the 14 kinds of doses and dose rates that individuals received or 15 were exposed to and then estimates of the integrated 16 population doses.
17 As one would expect in a circumstance like this, 18 there was a wide range.
The range went from tens of millirems i
19 to the total body and now I am talking just general public up i
20 to as high as doses of 30 to 40 rem to members of the general 21 public.
22 (SLIDE.]
23 MR. CONGEL:
The table as you will see in my slide 24 on the wall right now was taken from the Soviet slides with a 25 note that we added at the bottom.
Now you can see that the
53 1
dose and the settlements that are in the immediate vicinity of 2
the Chernobyl reactor had doses from several sources.
3 There were, as you can see in the second column, the 4
distances from the Soviet reactor, the dose, the D plus 15 5
means that it was 15 days into the accident when dose rates 6
rather of that magnitude were measured.
There was dose from 7
the cloud, dose from the build-up on the ground.
So there 8
were several sources.
There were doses also from inhaling 9
the radiciodines.
10 In any case, I didn't put this up to add too many 11 numbers, but this is the kind of information we received.
12 It appears that the Soviets had made many, many 13 measurements and many, many calculations and estimations and 14 surely as time goes on, the data vill be sifted and probably 15 organized in a different fashion but when we went through this 16 and we had the opportunity to ask some questions, the Soviets 17 indicated that they were refining some of the data.
18 An important thing to note as far as I am concerned 19 are the average doses that people received to the total body.
20 The last column says, " actual."
That is the dose that people 21 received from the build-up or radionuclides on the ground and 22 it ranges from two to about ten rem, numbers that one could 23 make note of.
24 The dose on child's thyroid and I am going to talk 25 about some protective measures they took in a few moments, but
54 1
the dose to child's thyroid ran up to a dose of as much as 250 2
rem.
3 The Soviets have mentioned that they are going to 4
follow the children that receive does of that magnitude or 5
greater very closely.
6 Could I have the next slide, please?
7 (SLIDE.]
8 MR. CONGEL:
Now this one is a summary of the 9
collective dose in terms of million man rem that the 10 population, the evacuated population, received before you were 11 evacuated and during the evacuation process.
12 Now this dose was associated with the plume exposure 13 and it was divided in order to be estimated, the regions were 14 divided up around the reactor primarily from the town of 15 Pripyat.
16 The number of people were as follows.
There were 17 about 45,000 people in Pripyat and then at regions going 18 beyond the town of Pripyat, there were approximately another 19 90,000.
20 Clearly, the people in the town of Pripyat were the 21 receivers of the largest dose.
22 May I have the next slide, please?
23 (SLIDE.]
24 MR. CONGEL:
To give a feeling of what kind of doses 25 could have resulted from consuming some of the contaminated
l 55 1
vegetation that was close to the plant.
We prepared this 2
slide from the slide that was presented at the meeting that 3
indicated the levels of activity that were found on leafy 4
plants close to the site.
4 5
If there was rather a direct consumption of leafy 6
vegetation, for example, with only washing of the vegetable 7
prior to consuming it, that person could have gotten a 40 8
millirem dose primarily from cesium and it would be a total 9
body component.
10 For meat, the same thing happened and if you 11 followed up on the level of the activity that was measured in 12 the cattle, you could come up with doses of 20 to 200 millirem 4
13 and for milk, of course, which is one of the more critical
\\
14 pathways involved, the values could run up to five rem for a 15 child's thyroid.
16 There is not a direct indication that people l
17 received these.
I wanted to translate though the numbers.
We 4
18 had many, many numbers and tables and this was just put 19 together to give you a perspective of what the contaminations 20 would cause.
21 May I have the next slide, please?
22 (SLIDE.]
23 MR. CONGEL:
Now in areas beyond the plant again, 24 even beyond the 30 kilometer zone, you still get doses to the 3
25 population.
Now in order to get a handle on just how much the
--+-
56 1
people could get once again in terms of million person rem 2
from both the passing of the plume and the building up of the 3
ground contamination and the associated external exposure, 4
there were regions of the Soviet Union, the European regions, 5
divided up with the populations and the doses estimated and 6
summed.
7 By this method, they could find or they calculated 8
that as so much as 8.6 million man rem would result in a 9
population just for the remaining part of this year and based 10 on the persistence primarily of cesium 137 in the environment 11 and the direct dose from that material, you could get as much 12 as 29 million person rem over a 50-year period.
13 Next slide, please.
j 14 (SLIDE.]
15 MR. CONGEL:
In order to summarize these numbers 16 that I have just briefly and quickly presented to you, we have 17 this table.
The 135,000 people that received an external dose
- 1 18 within 30 kilometers of the plant have a calculated value of 19 the 1.6 million person rem.
An additional nearly 75,000 1
20 people because of external exposure would have collected 21 another 29 million person rem.
22 A number that appeared in the Soviet report that was 23 the cause of some examination on a number of the people's part 24 had to do with the estimation of the dose to the population i
25 over a 70-year period from the cesium that is in the v
c
-4
57 1
environment.
2 Using mathematical models and not making any 3
allowances or assumptions of foods or perhaps removing certain 4
areas from food production, they had estimated as much as 210 5
million person rem as the collected dose.
6 Upon some careful discussion, in fact the subject of 7
one of the private meetings that we had with the Soviets, was 8
the basis for that number, in other words, the model and 9
parameters they used in order to come up with that value.
10 After some exploring, it appears that the Soviets J
11 used a model that most likely is conservative; that is, would 12 overestimate the actual dose.
13 Nevertheless, they calculated it so that they had a 14 perspective on what the cesium could cause over the time that 15 it persisted in the environment and it would give them an idea 16 of what controls, if any, they would place on those areas and 17 the food stuffs that are produced in those areas.
'i 18 COMMISSIONER BERNTHAL:
Was that the source of the i
19 wide divergence and estimated latent health effects, cancer
}
20 effects?
Was it primarily from that single number and the 21 conservative nature of the Soviets' assumption in that number?
22 MR. CONGEL:
It was primarily from that number, yes, 23 indeed.
As you can see, it dominates these summaries here.
24 COMMISSIONER BERNTHAL:
Yes.
4 25 MR. CONGEL:
That is one of the reasons it was such
58 1
a source of conversation at the meeting.
2 MR. DENTON:
These are from crops that have not been 3
planted and the measures have not been taken so a lot depends l
4 on future actions of the Soviet Unier.: as to what the dose 5
really will be.
j
'6 COMMISSIONER ASSELSTINE:
Frank, what do those 7
numbers translate into in terms of calculated projected l
8 cancers and cancer fatalities for those various ones on the 9
list?
4 10 MR. CONGEL:
Well, we had a rather extended 11 discussion on that.
The primary purpose and the reason for 12 the discussion is the wide range of doses that individuals 13 receive in order to come up with that collective dose.
14 The consensus that we came up with and there were 15 other country representatives there would agreed with it was 16 the following.
For those populations that received doses as 17 much as 30 or 40 ram, clearly they wculd fit into the analysis i
18 of potential health effects upon which the Beir Report is 19 based.
20 In fact, it was suggested to the Soviets that they i
21 examine and follow up that population very closely and add it l
22 to the existing data base which, of course, is primarily i
23 Hiroshima and Nagasaki just to see if they confirm or could 24 modify or sharpen up those numbers.
25 For the large population group that received on the
59 1
order of ten rem to maybe as much as 500 millirem, there was 2
also a strong suggestion made to the Soviets to follow up that 3
population.
During the discussion, during the give-and-take, 4
the Soviets pointed out that you are now getting into a region 4
i 5
where the doses are small enough and the statistics small 6
enough so that the real effects, if any, may be masked.
7 So it appeared after some discussion took place, the j
8 Soviets were willing to participate in a workshop to be 4
9 sponsored by IAEA where a data base of that type could be j
10 established.
They did indicate a willingness to participate 11 in that.
12 For the doses where there is less than 500 millirem, 13 there was, of course, much discussion on all sides about the 14 usefulness, the efficacy of following up that population.
15 The Soviets have some substantial problems to deal with first 16 of al? because they said that the town of Pripyat will be 17 uninhabitable quote for the foreseeable future, unquote.
1 18 What that means, they were not able to say.
They 19 just have to review the situation on a case-by-case basis.
3 20 When it comes to the 210 million person rem, that created a i
4' 21 lot of controversy in translating to health effects primarily 22 as Harold just mentioned, it is a dose not yet received.
23 It is a dose that is hypothesized not taking into I
24 consideration any changes of the land use.
It is a dose value i
25 that is based on a model that was developed by UNSCR, the
,i Y
i
-c-
-,--rv--
,m-
,--,..,---,_.-,r-,,,,_m--,--
_-,-.---,.-,,-.-,,--m_.,,_,mw-_.
60 1
United Nations Scientific Committee for the Effects of Atomic 2
Radiation.
They did use those models to predict this but as 3
they said, the model that they used tended to maximize things 4
which is completely consistent with radiation protection 5
practices.
6 If I now go back through that and try to relate it 7
to hypothesized cancer deaths, I believe people could be left 8
with the wrong impression.
9 Consequently, what came out of it was a' suggestion 10 for follow-up, a question on what to do with the people who 11 have relatively low exposures snd not to do anything with the 12 210 man rem until the number was sharpened up.
13 To respond to your question directly, Commissioner, 14 is that the Beir Report of 100 effects per million man rem is 15 the one that we apply on the average basis.
16 COMMISSIONER BERNTHAL:
Let me ask one question.
17 The dose that you project and predict especially this cesium 18 dose of 210 times ten to the sixth is, of course, subject to 19 controversy.
My understanding is though that there is one 20 number that is not dependent on what assumptions you make for 21 cancer inducement if you will which can vary all over the map 22 or at least vary by an order of magnitude depending on what 23 your school of thought of theology is in these matters.
24 Is it a correct statement as I believe I saw 25 somewhere that whatever your basis is the incremental effect
61 i
1 will be about 25-percent over what you would calculate by 2
whatever system you choose for the cancer effects from natural 3
background radiation?
Is that a fair statement?
That number, 4
I think, has been quoted in one or two places recently.
5 If you understand what I am saying, you pick your 6
system and then you say, "I would project this many deaths 7
from car!cer from natural background radiation."
"I would 8
project 25-percent more than that from the effects of this I
9 accident" or are you prepared to comment on that?
10 MR. CONGEL:
If I understand the question correctly, l
11 the comparison with natural background is appropriate to l
12 compara the approximately 100 millirem per year per 13 individual--
14 COMMISSIONER BERNTHAL:
Exactly.
15 MR. CONGEL:
-- from na ural background to whatever l
16 increnantal dose they got as a result of the accident.
l 17 COMMISEIONER BERNTHAL:
Right.
i I
18 Kl. CONGEL:
But it varies because people received 19 anywhere from virtually zero up to in the general public 40 to O
50 rem.
I don't see how you could get a fixed 25-percent l
differential with these numbers that I am saying.
COMMISSIONER BERNTHAL:
I am talking about the 23 integral number and the integral population.
So you assume an 24 even distribution, even distribution from background 25 radiation, and then you got some increment that you calculate N
.._._,__.-_...,,.__.__.m.
_.._..___....,.__,,_-__,..,.,,c,.__
62 1
beyond that.
2 MR. DENTON:
I remember a number --
3 COMMISSIONER BERNTHAL:
I think the New York Times 4
carried that number.
5 MR. DENTON:
This was probably the most 6
controversial area because of the fact that the doses have not 7
occurred and they can takes steps to eliminate them and there 8
was a feeling that people jumped on the numbers as though they 9
had already happened when, in fact, the Soviets may take 10 actions to prevent them.
11 I remember a number that said with all the 12 qualifiers that you put in there that this kind of exposure 13 could increase the incidence by four-tenths of a percent is 14 the number that I heard.
15 COMMISSIONER BERNTHAL:
That is the total cancers 16 though.
That is not what I am talking about.
The total 17 cancers expected for the integral population is one number and 18 yes, that is the number that I saw, too, that less than one 19 percent increment beyond the total expected cancers.
20 What I am talking about is a different matter 21 because you pick the system, whatever it is for cancer 22 production, and then it applies that you will calculate a 23 certain amount from natural background and then a certain 24 increment over that as a consequence of the accident.
So you 25 are only comparing natural background expectation with the k
63 1
increment above natu::al background.
I 2
Maybe it is enough said.
3 MR. CONGEL:
I believe I know what you are saying 4
but these numbers would not give you that 25-percent over 5
natural background at least from what I have looked at.
You i
6 can express it that way but I don't know what the number would 7
be.
The only one that I know is that the Soviets used a value 8
and they said an increase of four-tenths of one percent if the 4
9 210 million man rem number persists.
10 COMMISSIONER BERNTHAL:
That is of total cancers?
11 MR. CONGEL:
That is of total cancers.
12 COMMISSIONER BERNTHAL:
I agree with that.
The 1
13 other one is a different number.
14 COMMISSIONER ASSELSTINE:
Frank, you gave a couple 15 of categories.
Do you have estimates or did the Soviets 16 provide estimates for the number of people in those three i
17 categories?
ffas it less than 500 mr?
i 18 MR. CONGEL:
Yes.
19 COMMISSIONER ASSELSTINE:
Between 500 and 10 R?
l 20 MR. CONGEL:
The people who received in the 30-40 21 rem range, I have it in my notes someplace, it was on the 22 order of several thousand.
Now the people who received under l
23 that value, in fact, there was an average value of 3.3 rem to 24 a population --
25 (Mr. Congel and Mr. Denton conferring off the I
64 1
record.]
2 MR. CONGEL:
I was confirming it with Harold.
I 3
believe it was 3.3 rem average dose to like 75 million 4
people.
I can get that but I want to make sure that that is 5
correct on the record.
6 COMMISSIONER ASSELSTINE:
That is fine.
7 MR. CONGEL:
I am just going from my memory on that.
8 COMMISSIONER BERNTHAL:
Let's see, 3.3 rem to how 9
many again over seven years?
10 COMMISSIONER ASSELSTINE:
Seventy years.
11 MR. DENTON:
That number is the food pathway number 12 associated with the 210.
13 COMMISSIONER BERNTHAL:
But how many people is that 14 again?
15 MR. DENTON:
That is the 75 million people and that 16 is the same area that came into the controversy because it 17 hasn't been delivered.
That is the food pathway one that 18 generated so much controversy and there was discussion as to 19 whether three was the peak or the three was the average and 20 those kinds of numbers.
21 I got the feeling that there is a certain softness 22 in all these numbers and they should not be looked upon -- it 23 will probably take another conference with epidemiologists and 24 health physicists to straighten out these kinds of numbers.
25 COMMISSIONER BERNTHAL:
Yes.
That sounds like five l
65 1
times natural background.
2 MR. CONGEL:
No.
3 COMMISSIONER BERNTHAL:
Three R over seven years.
4 MR. CONGEL:
Seventy.
5 MR. DENTON:
Seventy.
It is calculated over 70 6
years.
7 COMMISSIONER BERNTHAL:
Oh, all right.
Fifty 8
percent.
9 COMMISSIONER CARR:
Are all these numbers over a 70 10 year period for collective dose?
11 MR. CONGEL:
They were not consistent on how they 12 were presented.
Some were 50 years and some were 70 years.
1 13 The number for the food pathway cesium was for 70 years.
If 14 you will remember one of my earlier slides, there were two 15 tables presented or two columns in the table, one for the 16 first year like the remainder of 1986 and then over a 50-year 17 period.
18 MR. DENTON:
The head of this particular discussion 19 was Dr. Benison who is the chairman of the International 20 Commission on Radiation Protection from which all these 21 estimates flow.
So as you would guess, there was a lively i
22 discussion of the application of ICRP type criteria in this 23 situation.
24 COMMISSIONER BERNTHAL:
But it is a key point, I 25 think, then that you are saying or somebody is saying that up
+.
66 1
to 70 million people over a 70-year period of time should 2
expect 50-percent more radiation than they would normally get 3
from natural background exposure.
4 COMMISSIONER ASSELSTINE:
That's right.
5 COMMISSIONER BERNTHAL:
That is essentially what you 6
are saying.
i 7
MR. CONGEL:
Given the validity of all of the 8
assumptions that go into deriving that number.
9 MR. DENTON:
The discussion really got down in the 10 details, the soil composition, what are the appropriate 11 assumptions for that type terrain.
They obviously need to 12 make agricultural experiments, tests to see the uptake.
It 13 seems to me that it is going to be uncertain until they have 14 actually done some of those tests, measured some of those 15 crops and decided what actions they are going to take as to 16 whether they modify the consumption of those foods.
)
17 So all these doses are future potential subject to i
i 18 change.
19 MR. STELLO:
I think it is important maybe to get a 20 perspective on the number, too.
A number that always sticks 21 in my mind is the number at TMI.
It was 86 millirem as I 22 recall was the early projected maximum dose right near the 23 site boundary.
I found that number intriguing because the i
24 variation in background radiation around Three Mile Island is i
25 86 millirem and we are talking about doses that are down well I
67 1
within that range and I think it is going to be very, very 2
difficult, the difference in dose rate between here and Denver 3
is significantly greater than that amount.
4 When you are down so far down in the range of where 5
you are taking very tiny numbers and multiplying them by very 6
large numbers for a very long time and I think it is an area 7
for which there is significant controversy and I remember the 8
Beir Report had a footnote that they didn't think that they 9
could, in fact, conclude that there were adverse effects for 10 any dose rate less than 100 millirem.
11 MR. CONGEL:
It was the other way.
It could not be 12 established whether there were adverse effects for dose rates 13 below 100 millirem.
14 MR. STELLO:
Below 100 millirem.
15 COMMISSIONER BERNTHAL:
But that is because that is 16 your expected annual dose from natural background and you get 17 variations at least a factor of two around that value by 18 moving to Denver.
19 MR. CONGEL:
You can get a maximum risk factor from i
20 radiation exposure by assuming all of the observed cancers in 21 the United States are due to natural background just to get a 22 handle.
You will find out that it still does not yield a risk 23 factor much different from the one that we use for evaluating 24 effectiveness of certain procedures and additional equipment, 25 for example.
68 1
MR. STELLO:
I don't think that this is an issue i
2 that could be settled today here.
It is one for which there 3
is such controversy.
4 COMMISSIONER CARR:
I don't see how they will ever 5
figure out who got 500 nr.
I 6
MR. CONGEL:
Especially without badges.
7 COMMISSIONER CARR:
No data.
8 MR. CONGEL:
That's right.
9 COMMISSIONER CARR:
Unless they go around now and 10 say, "Well, we are going to start measuring how much they are i
11 getting now," then they might get a good data base.
I 12 MR. CONGEL:
It would involve a detailed 13 reconstruction of where the people were and it would be 14 difficult.
15 COMMISSIONER BERNTHAL:
The point is well taken 16 though, Ken, that even now it is of great value.
You wpuldn't 17 get the numbers for the early days of the accident itself but t
i 18 you certainly could set a limit even now.
I i
19 COMMISSIONER CARR:
If you want to start the data i
20 base now, it ought to be pretty accurate.
I 21 COMMISSIONER BERNTHAL:
You will set a limit at I
i 22 least and that in itself would be of great value.
I 23 CHAIRMAN ZECH:
Let's move along, please.
.I 24 MR. CONGEL:
Next slide, please.
25 (SLIDE.]
.s 69 1
MR. CONGEL:
What I have here is a chronology of the 2
emergency measures that were taken early on in the accident.
3 As I said on my first slide, the direction of the winds were 4
around the town of Pripyat so the first advice that was given 5
to the population was to remain indoors and close the windows.
6 Of course, all of the schools were closed and 7
children were certainly forces to remain indoors.
8 At that same time, there was a massive distribution 9
of potassium iodine, the thyroid blocking agent for 10 radioactive iodine, to prevent the uptake of radioactive 11 iodine.
12 COMMISSIONER ASSELSTINE:
You say immediately after 4
13 the accident.
I take it, that was the first day.
14 MR. CONGEL:
Within hours, yes.
15 COMMISSIONER ASSELSTINE:
All right.
16 MR. CONGEL:
So that would be like the first i
17 morning.
The accident occurred between 1:00 and 2:00 a.m. so 4
18 this would probably be 7:00 or 8:00 o' clock but at that point, 19 there was some dose measured in Pripyat but it wasn't 20 significant enough for them to take any more severe action 21 than this.
22 Fortunately, they had the potassium iodide 23 distributed and the population indoors when the wind changed 24 direction.
The dose rate went from 50 to 100 mr per hour within the town of Pripyat up to over one R per hour on the 25 4
I
70 1
second day.
2 At that point, the decision was made to evacuate the 3
population.
When they made the decision to go which was at 4
2:00 p.m. on the 27th --
5 COMMISSIONER ASSELSTINE:
That is Sunday.
6 MR. CONGEL:
-- they moved.
Yes, that is Sunday.
7 By 5:00 o' clock in the afternoon they had the people out.
8 There was a mention made by the Soviet lecturer that it was 9
apparently quite a site.
They had brought in a thousand or so 10 buses to evacuate the people and there was one difficult part 11 of it because the path of getting the people out of Pripyat, 12 out of the area, did take them through an area of higher 13 radiation doses near the plume, i
14 So some of the bus drivers that had to repeat the 15 trip got an accumulated dose because of the area they had to 16 traverse.
17 After the town of Pripyat, the 45,000 people were i
18 evacuated, the remaining population was evacuated primarily 19 because the plume was changing direction and causing doses 20 over a wider area.
21 Consumption of milk with a value of more than ten to 22 the minus seven curies per liter was banned and they indicated 23 that the ban on that consumption of milk was very effective.
24 In fact, all of the children within the 30-mile radius were 25 sent to summer camps and it was interesting to us because they
71 1
indicated at the meeting that the children were just going to 2
be reunited with their parents this past weekend after the 3
session was over.
So the children had been separated from 4
their parents since the accident occurred.
1 5
The resettlement of the people, the adults anyway i
]
6 from Pripyat, it took place in two areas around Kiev.
Because
].
of the apparent longer term nature of the evacuation, there 7
8 was new housing being put up for permanently holding the 1
9 people.
10 CHAIRMAN ZECH:
How accurate is the measurements i
11 during the evacuation of the route they took?
12 MR. CONGEL:
The data that they indicated at the
}
13 meeting, they had many monitors, counters around.
From what I j
14 gathered, they had individuals and vehicles moving around and 15 making measurements in different areas.
i 16 They also apparently had people making measurements i
17 of the dose in the buses because they did indicate the bus j
18 drivers got doses --
j 19 CHAIRMAN ZECH:
Did they tell you what those doses 20 were during that evacuation?
21 MR. CONGEL:
No, sir.
All I got were readings of mr l
22 per hour at this point at this time and then readings of mr 23 per hour at another point at another time.
We never got a I
24 complete listing of all the raw data.
i 25 CHAIRMAN ZECH:
But they do have the data?
\\
1
72 1
MR. CONGEL:
Apparently they do but they said that 2
there is a large volume of it and probably during the workshop 3
would be --
4' 4
CHAIRMAN ZECH:
It would be interesting to follow 5
through and get as much specific data as we can.
l 6
MR. CONGEL:
Everybody had the desire there to do j
7 some of the analysis on their own.
4 8
CHAIRMAN ZECH:
Sure.
i 9
COMMISSIONER CARR:
Did you get the impression that 10 it was a pre-planned evacuation?
+
j 11 MR. CONGEL:
The question was asked.
They said they l
12 had in place evacuati'on plans but there was a randomness 13 apparent with it.
They didn't go completely according to 14 their book.
J i
15 MR. DENTON:
In fact, I think they said that the 16 plan that they looked to first, they had to throw out because i
4 17 it did not fit the situation and then they had to make new 18 plans to cope with this situation.
}
19 On the question of data, they did say that they had 20 a lot more data than they presented at the conference, that 21 they tried to present only the part that would fit in the 22 schedule and they would make the remaining data available in i
23 some other form in the future.
24 So they seemed very willing to make all the data 1
l 25 they have available at some time in the future.
l
73 l
1 CHAIRMAN ZECH:
Very good.
2 COMMISSIONER BERNTHAL:
Do we know exactly what 3
their plans were for evacuation?
4 MR. DENTON:
I don't think there was much more that i
5 I heard other than what I just said, that the original plan 6
was decided that it was not workable.
i 7
COMMISSIONER BERNTHAL:
But we don't know what the 8
original plan was.
1 9
MR. CONGEL:
It has not yet been translated but we l
10 received copies that purport to show what their emergency plan 11 was.
Late last week when I referred to the meeting that we 3
i 12 had with the Soviets prior to the formal meeting, they gave 13 out a copy of the emergency plan.
Of course, it was in 14 Russian and we haven't seen it yet but it supposedly. outlines 15 some of the details.
16 When we get that and it is translated, certainly we 17 will be happy to distribute it.
18 MR. DENTON:
Representatives met with them just on 19 that aspect in a private session.
4 20 COMMISSIONER ASSELSTINE:
Frank, did they have 1
4 21 potassium iodide stockpiled in the area?
22 MR. CONGEL:
Apparently they did, yes, because it 23 was available quickly.
24 COMMISSIONER BERNTHAL:
You haven't debriefed or l
25 vice-versa the FEMA people then on their private discussions i
d
- - ~, - - - - - -.
.-,,-ne.-.,__...n.n-
_y,,,,,--.
n--
a3
--.,.,_,my,--.
74 1
on that matter?
2 MR. DENTON:
We met every day but I didn't have the 3
impression that we knew a lot about what plans they were and 4
since they.said they weren't workable, we didn't pursue that.
5 MR. CONGEL:
May I have the next slide, please?
6 (SLIDE.]
7 MR. CONGEL:
We are running a little bit late, but 8
these are just some more of the high points that I wanted to 9
indicate as to what happened.
They have already in place with 10 standards of what contamination levels would be acceptable for 11 the general population.
12 They issued them specifically in the areas 13 surrounding, in special agricultural areas surrounding the 14 site in May.
They talked about the degree of medical care 15 that was available to the people.
They did many, many blood 16 samples and evaluations of the evacuees and it is on that J
17 basis that they established that there was no immediate damage 18 associated with the doses.
19 They talked but not specifically about the setting i
20 up of long term monitoring programs.
They said positively 21 that they were going to follow up the children that got high 22 thyroid doses but as I indicated to you earlier, it is still 23 uncertain as to what they are going to do with the adults in 24 the population that received external doses.
25 Next slide, please.
i
75 1
(SLIDE.]
2 MR. CONGEL:
There is a description albeit somewhat 3
brief about decontamination procedures that were being 4
followed.
5 COMMISSIONER ASSELSTINE:
How large an area around 6
the plant was contaminated to the point where some 7
decontamination is necessary?
8 MR. CONGEL:
Well, I didn't get specific information 9
on how big that was.
They showed some -- in fact, even in the 10 introductory video, some decontamination.
Well, there was 11 also a video out in the lobby that they showed about what work 12 was being done around the site.
13 I don't know.
Apparently they tried to 14 decontaminate some of the houses close into the site like at 15 Pripyat but the residual levels are still high enough so that 16 they have not made any estimations as to when they could move 17 the people back in.
18 They are looking at different kinds of washing down, 19 high pressure water, the chemical de-cons, for removing the 20 contamination but the thing that they have been most 21 successful with is the vehicles that are used in contaminated 22 areas, once they get beyond a certain point I don't know 23 and once again, if they said it, I didn't hear it, at what 24 point to do that but they washed any mud or any dust, things 25 like that, off the vehicles before they transport them out
76 1
beyond that.
2 As you can see from the last bullet on this slide, 3
they said the long term decontamination procedures are being 4
researched.
So how effective they will be is something that 5
they are presently working on.
6 COMMISSIONER ASSELSTINE:
How large an area remains 7
evacuated?
8 MR. CONGEI:
The 30 kilometers.
9 COMMISSIONER ASSELSTINE:
All of it?
10 MR. CONGEL:
Yes.
11 COMMISSIONER ASSELSTINE:
all right.
12 MR. DENTON:
Let me then give the conclusion of l
13 where the IAEA will go from here.
14 I think I had mentioned before the formation of this 15 international nuclear safety advisory group that reports 16 directly to director general Blix.
That is a 13-member 17 experts from around the world.
Herb Kouts from Brookhaven is 18 a member of that group.
Their charter is to provide the 19 director general of the IAEA a report on all that was said and 20 recommend future IAEA actions.
21 That report, I think, will be given to the agency at 22 the meeting that is coming up in about a month.
It sounds as 23 if that there are about 13 areas in which the agency is 24 considering that further programs would be worthwhile and I 25 will just run through some of them for you to give you a feel
1 i
77 l
1 for the kind of things the agency is thinking about doing.
2 These would be programs and areas where the nations 3
could share experience on severe accident consequences and i
4 models, man / machine interface, the balance between human l
{
5 actions and automatic actions, experience in operator training 6
and accreditation.
7 The question came up as to whether IAEA's standards 8
that were proclaimed some time back be updated and reviewed, 9
whether or not there need to be meetings on fire protection 4
l 10 techniques and improvements, the establishment of common i
11 levels for food stuffs among the nations, workshops to 12 exchange experience on decontamination practices, information j,
13 on environmental monitoring, a meeting of specialists to j
14 determine how individual collected doses might be further t
}
15 clarified, whether or not epidemiological studies for late i
16 health effects would really be valuable.
l 17 I think in that area they concluded that it would be 18 valuable but only for those higher exposed populations not for 19 the general population.
1 20 The medical profession seemed to think a meeting on T
21 various therapeutic measures would be useful probably done in i
j 22 connection with the World Health organization.
I suggested i
23 there might be a follow-up on the effects of the potassium i
i i
24 iodide treatments and whether or not there were any delayed a
i 25 effects and finally, follow-up on improved measures to l'
i J
78 1
determine from biological measurements total body radiation.
2 These recommendations will be distilled and will be 3
coming forth from this so-called INSAG group to the IAEA 4
board of directors in a formal sense.
As a staff, we have 5
said that we are going to write a factual report.
The factual 6
report is now a lot easier since we have this amount of 7
information.
8 We will go back and consult with our colleagues at 9
EPA and NIH and FEMA and try to expedite the production of 10 that report which will be a factual report.
We will follow 11 that report on what lessons learned are for us.
12 I think we need time for this information to seep in 13 to all of us.
It is a lot of information in a lot of areas.
14 It is quite clear our reactors are quite different.
I think 15 we have designed out reactivity excursions as a class but we 16 are going to go back and look at things like ATWS again and 17 see how that rule might be interpreted in light of what 18 happened, look at low power operation, go back and look at the 19 adeqpacy of controls through 50.59 type procedures and these 20 kinds of things are things we are going to look at.
21 But I don't see any areas in which we need to make any immediate changes in our regulatory basis for licensing.
22 23 I guess with that, I will close and answer any 24 questions.
25 CHAIRMAN ZECH:
Thank you very much, Harold.
Do my
79 1
fellow Commissioners have any questions before we conclude?
2 Jim.
3 COMMISSIONER ASSELSTINE:
Just a couple.
One for 4
Frank Congel, on one of the charts, this one here, the 5
estimates of the dose effects --
6 MR. CONGEL:
Yes.
7 COMMISSIONER ASSELSTINE:
I noticed that the dose a
from radioactive fallout in seven days in rems was actually higher at the 29 kilometer distance from the plant than at 9
10 three of the closer in distances.
How do you account for 11 that?
Was that the nature of this accident in that the 12 explosion shot things way up?
13 MR. CONGEL:
It was the way in which the material i
14 distributed about the site.
It was not an even distribution 15 around the site.
There were prevailing wind patterns.
You 14 have to match the wind patters, the height of the release, the 17 make-up of the release as a function of time.
la COMMISSIONER ASSELSTINE:
Yes.
19 MR. CONGEL:
I mentioned earlier about hotter spots 20 and that is exactly what you see in places where there is not 21 a uniform dose.
22 COMMISSIONER ASSELSTINE:
Another question I had, 23 Themis, you had described the safety improvements that the 24 Soviets are undertaking for the RBMK plant.
I guess they all 25 seem to be in the right direction.
The logical question is
80 1
are they doing enough to address the weaknesses in that 2
particular design.
Do we have any kind of a judgment on that?
3 MR. DENTON:
Let me step into that one before you 4
address it to Themis.
It seemed to me that all of us thought 5
they were in the right direction and that the soviets have 6
indicated a willingness to collaborate with us in future 7
safety studies.
8 We got asked a lot about how do they compare.
That 9
didn't seem to be the kind of if we got drug into that other 10 than it probably could not be licensed here, would not support 11 the kind of dialogue we hope to have with them.
12 So I tried to avoid ticking off the areas in which 13 they differed.
We have only looked at this particular area, 14 reactivity excursions.
They didn't tell us about how the 15 plant was designed for loss-of-power, transients and other 16 areas.
17 So I think the ones that they have done are 18 certainly in the right direction but I think the soviets have 19 invited us all to comment on how they might improve in this 20 shut down system.
They are interested in the use of PRA 21 techniques to identify vulnerabilities but with that kind of 22 background, I will let Themis answer because people kept 23 pushing the NRC to draw comparisons and I am just very 24 encouraged that this is the first time that door has opened 25 and would like to keep it open if at all possible as that is
81 1
the best way to improve safety world wide.
Themis,'do you want to add anything?
2 3
MR. SPEIS:
I don't have anything else.
That 4
suffices.
5 CHAIRMAN ZECH:
It sounds like a good answer, 6
doesn't it, Themis?
7 COMMISSIONER ASSELSTINE:
Yes.
l 8
(Laughter.)
9 COMMISSIONER ASSELSTINE:
But it will be a matter of i
f 10 further discussion either as part of the advisory group or I
11 some of the other discussions that will be going on over the 12 next few months, I take it.
13 MR. DENTON:
Yes.
They have indicated they plan an t
14 analytical and experimental program.
This isn't the last 15 word.
It is a snap shot in time and they may make further
{
16 changes.
They said about half their plants of this design are 17 shut down right now either because of this accident or they 18 shut down for refueling and I think it is just very i
19 encouraging to see their interest now in this whole broad 20 range of safety matters.
j 21 COMMISSIONER ASSELSTINE:
When you look at the j
22 offsite consequences that we have been talking about, what 23 does that tell you about the wisdom or the benefits of 24 considering offsite contamination of property and doing cost 1
j 25 benefit analyses?
Is that something that we can learn 4
j i
oo 82 1
something from, do you think?
2 MR. DENTON:
I had not really thought about that.
I 3
think I advocated that position at one time just from a 4
philosophic basis.
It does tell me the value of containment.
5 If you look at the amount of iodine that got out at TMI and 6
the value of iodine that got out here, they differ by about a 7
factor of a million.
8 So containment which will delay or prevent major 9
releases is extremely important.
I think this is illustrated 10 if you compare TMI to what happened here.
The question of 11 what do you include when you do a cost benefit analysis, I 12 think, is one we talked about.
I will re-examine that 13 question and try to address it.
14 COMMISSIONER ASSELSTINE:
All right.
15 MR. STELLO:
I think maybe a broader answer is that 16 we haven't even written the technical report yet and we are 17 really trying to understand that.
To now entertain or look at 18 what is it that we can learn before we even have written a 19 technical report at least suggests to me maybe we are being a 20 bit premature to do that and I would prefer to answer those 21 questions when we have had the time to sit down and reflect on 22 what we have learned and write that report and more of us have 23 a chance to read that report and then I have already appointed 24 a group to try to answer that kind of question.
25 It would seem better to me to wait until we have
I 83 1
done that job rather than sit here and try to shoot from the 2
hip.
I tend to regret doing that whenever we do it and I 3
would prefer if we could to have some time to give that the kind of thought I think it ought to have before we get into it 4
i 5
if we can.
6 COMMISGIONER ASSELSTINE:
I certainly don't have any 7
problem with your taking the time to look at it but it also 8
seems to me that a fair question at this point is where you have an accident that may not result in offsite prompt l
9 10 fatalities and that appears to be the case here, where you 11 have some level of latent health effects but where you have 12 one heck of a mass whether you consider the mess as part of 13 the balance in deciding whether you reduce the likelihood of 14 that kind of an accident is at least a fair question now.
15 MR. STELLot I don't disagree with you but I think it ought to take into account the fact that that kind of an 16 17 accident in a reactor of that type is not one of the accidents 18 we can have in a U.S. reactor.
19 I don't know whether you reacted as I did when I 20 read the report but they ejected somewhat on the order of ten 21 tons of fuel from that reactor out into the environment as 22 part of the accident.
We are talking about a machine that is significantly different and it needs to be studied and 23 24 understood and all of that considered in trying to answer 25 those questions.
_m,..,_,
84 1
I think fairness should suggest that that be given 2
the kind of thought that it deserves before we try to answer 3
it.
4 COMMISSIONER ASSELSTINE:
Sure.
But it also strikes 5
me that that goes more to the question of now would that kind 6
of an accident likely occur or under what conditions would 7
that kind of an accident resulting in large offsite 8
contamination of property occur in Western style plants as 9
cpposed to the principle of should that be a factor that wa 10 consider.
That is, do we want to avoid large scale offsite 11 contamination of property.
12 MR. STELLO:
That is precisely the question I was 13 answering.
How much of what happened there is the result of 14 the very enormous amount of energy that was put in that 15 reactor, 500 times normal power, normal power at 3,000 16 megawatts, you talking about an enormous calculated albeit 17 amount of energy that went in.
To what degree did that create 18 the particular contamination problem they have and how 19 important is it.
20 I don't believe you can answer that sitting here 21 without thinking about it a great deal, studying it and 22 understanding how significant that kind of unique aspect which 23 we do not have in our reactors contributed to the very 24 problem.
25 I think you need to study it first.
All of us can
85 1
sit here and speculate but is that wise and I suggest that we 2
ought not to do that and would rather not if you will allow 3
me, I would rather not.
4 COMMISSIONER ASSELSTINE:
Sure.
Are there any 5
implications for multiple unit sites in this?
TMI was a 6
multiple unit site and the second reactor was shut down.
Are 7
there things that we should consider or look at in terms of a
multiple units particularly where the units are operating at 9
the time?
10 MR. DENTON:
I think that is a fair question and 11 one we will consider.
At TMI they tended to try to isolate 12 the two units.
13 COMMISSIONER ASSELSTINE:
Did you find out something 14 about the training and qualifications of the Soviet operators, 15 what their background was, did they grow up in the nuclear 16 power program over there and what kind of training they 17 receive?
18 MR. DENTON:
As you can gather the scope of this 19 meeting was so broad, you didn't get in deeply in any area.
20 They said, yes, that they were tested and that they were 21 trained but they also emphasized that they did not have enough 22 simulators and that that was definitely one area in which they 23 were going to pursue.
So the answer is no, we didn't find out 24 the details and that is one of the topics for which a further 25 meeting with them, I think, would be very useful.
86 1
I think they are very interested in how we train our 2
operators.
3 COMMISSIONER ASSELSTINE:
The last question, I 4
l 4
guess.
You mentioned a couple of areas that you want to go 5
back and take a look at, reactivity excursion accidents and 6
ATWS.
Is that because of the pressure pulse questions and to 7
what extent or what is it about this that raises questions in l
8 your mind or that you want to take a look at?
9 MR. DENTON:
I think it is more this is an accident 10 involving reactivity excursions which were studied years ago 11 at Idaho and a spurt test and those kinds of things and we i
12 thought we had designed them out and had passa1 rules to make l
13 sure that they couldn't occur and it just seems prudent to go 14 back now in light of what we have learned where you have a 4
15 real one occur, go back and re-look at that matter.
1 16 It is not because I have a known problem that exists i
17 there.
In fact, my sense is that we don't have a problem in J
18 that area but I think it is worth examining past decisions.
]
19 COMMISSIONER ASSELSTINE:
Good.
T1.ose are the only 20 questions I have.
21 CHAIRMAN ZECH:
Fred.
I j
22 COMMISSIONER BERNTHAL:
I think I won't prolong 23 this.
There are lots of questions that could be asked.
I 24 just want to make a comment.
I think it was always and is 25 always a very admirable trait to say, "I don't know" and I i
i i
9
-.---..,---..-,-.-.-.-,.-.---y-.,,.,------.--w-..,---,-.--,--.,------,,.-
--.y,.
-,e,,m.,.----
_,-~---,-%
-,-.r..e..-w.,----.
,yv--
87 1
always thought that was an admirable trait in either students 2
or professors when I was in academia but I would also urge 3
that we not err on the side here of failing to provide 4
informed opinion.
5 I believe this agency-did that in the immediate days 6
following the Chernobyl event because somebody is going to 7
provide opinion whether informed or not and be cautious and 8
careful but I would urge you to not be afraid to speak out to 9
the extent that you feel your comments might be warranted 10 because I think there is a large fraction of the population 11 that is interested in the implications of this accident and we
. 12 will learn more as we go along.
13 But I would hope that we not be overly reticent 14 about providing informed opinion because there will be plenty 15 of opinion provided that is informed and otherwise and has 16 been and will continue to be.
That is the only comment that I 17 would make.
18 CHAIRMAN ZECH:
I think the point is well taken.
On 19 the other hand, I do think it is important that something as 20 really critically important to world nuclear safety as this 21 issue is does deserve some careful study before we make too 22 many radical conclusions.
23 I think some of the statements that have been made 24 perhaps have been regretted by those who made them and it is 25 my view that this is just too important an issue to not be
(
l 1
88 1
relatively certain about our position.
2 Safety and the people we are talking about in our 3
country and around the world at least to me makes the issue 4
one of tremendous importance and where we have to exercise 5
some caution.
6 Are there any other Commissioner comments or 7
questions?
8 (No response.]
9 MR. STELLO:
I have no problem with it.
I was 10 speaking to a piece of paper that will come before this 11 Commission and you will decide ultimately what the l
12 implications of this reactor are and speak for this agency.
I 13 don't think we have a problem with people in this agency being i ',
14 bashful to talk to anyone.
15 I don't anybody could accuse us of doing that.
We 16 will offer our opinion but I think it is a very important 17 distinction.
We intend to come back with a piece of paper to 18 tell the Commission this is what we think this Agency ought to 19 do in light of this accident.
That is different in my view 20 and that is what I was speaking to.
21 COMMISSIONER BERNTHAL:
Sure.
22 CHAIRMAN ZECH:
Let me just conclude then by saying i
23 that first of all I think I want to thank all of you and the 24 staff for your very, very excellent presentations and also for
'25 the work you have done in Vienna and here in order to try to l
89 1
come to grips with learning the lessons from this very tragic 2
but significant accident.
3 I think, too, Harold, you pointed out that your impression that the Soviets have been very forthcoming and 4
5 very candid is also very significant and their willingness to i
6 have a dialogue and continue exchanging information with us, I i
7 think, is very significant, too.
8 It seems to me that also significant is their 9
apparently very frank discussions of their design and the 4
10 design differences they have and as I understand what you have 11 told us and others have elaborated that they went to some 4
12 length to talk about the positive void conditions which is 13 cbviously a significant difference from our reactors.
l 14 Also, they talked about their slow control rod j
15 insertion rate and again combined with apparently what was
)
16 described as easy to override safety and protection systems is i
17 also -- those are the kinds of things that I think are very 18 significant and apparently the Soviets have presented those 1
19 very candidly.
4 20 It seems to me also the Soviets' belief that was 21 expressed that the operators apparently lost their sense of 22 vigilance toward safety is a very significant statement and l
l 23 certainly one that would be important for all those involved l
24 in nuclear power throughout the world to certainly give 25 considerable thought to because vigilance to safety certainly f
l
90 1
has to be the number one priority,of all of our operators and 2
the Soviet operators as well as others throughout the world.
3 The fact that apparently the Soviets have stated 4
that there were deliberate violations of a number of safety 5
procedures by their operators, again is a very candid 6
comment.
I think they deserve credit for giving those kind of 7
apparently straightforward, forthright, candid statements.
8 So it looks like from what you have told us that i
9 there will be much to learn both from perhaps a positive as i
10 well as a negative way.
Maybe we can learn and perhaps even 11 gain confidence that some of the things that we have been 12 doing and emphasis we have been doing is the right thing as 13 well as to see if there are other things that we can learn 14 from this very important event.
15 So the candidness, I think, is what you have told us
{
16 and emphasized is, I think, significant.
17 I would also like to encourage the staff to continue 18 their diligent efforts in getting the facts and in assembling 19 everything that we can in order to come up with eventually f
20 some conclusions that will be very, very important.
4 21 I would like to encourage your working with other 22 agencies of our government as well as other countries in this 23 exchange of information which seems to me to be a very healthy i
May to improve safety of operations world wide.
I think the 24 i
25 understanding that we can gain from this will be perhaps more
91 1
significant than we realize especially when we see the 2
openness and the candidness that is being expressed.
3 So it seems to me that it behooves us to certainly 4
take advantage of the information that is being made available 5
to analyze it carefully and thoughtfully and to see that it i
would apply to our country and to our operations of nuclear 6
7 reactors in our country.
8 So I do think that the staff should be commended for 9
the efforts that you have taken to date and for the i
10 professionalism that you have obviously shown and for your 11 thoroughness in working in this important area.
12 So with that, let me thank the staff for a very,
,f 13 very fine presentation and the meeting will be adjourned.
14 (Whereupon, the commission meeting was adjourned at 15 4:15 o' clock p.m.)
J 16 17 18 I
19 20 21 22 23 24 I
25
.___.___,.__m_.,___,_
u REPORT ON THE IAEA MEETING ON THE CHERN0BYL ACCIDENT HAROLD R. DENTON THEMIS P. SPEIS BRIAN W. SHERON FRANK J. CONGEL PRESENTED TO THE NRC COMMISSIONERS SEPTEMBER 3, 1986
/
1 KEY DESIGN AND HUMAN FACTOR' ASPECTS WHICH CONTRIBUTED TO ACCIDENT SEVERITY HUMAN FACTOR ASPECTS TEST PROCEDURES VIOLATED CERTAIN SOVIET SAFETY REGULATIONS, OPERATORS VIOLATED CERTAIN PARTS OF TEST PROCEDURE.
SOVIETS BELIEVE OPERATORS LOST SENSE OF VIGILANCE TOWARDS
- SAFETY, DESIGr! ASPECTS APPARENT SIMPLICITY WITH WHICH SAFETY AND PROTECTION SYSTEMS COULD BE OVERRIDDEN.
SLOW CONTROL ROD INSERTION RATE.
POSITIVE VOID REACTIVITY FEEDBACK.
A
F
\\
l I I II "nn l
II I,.
ll l
II l-ll l
II I
I
\\
,U e
a
\\.
./
.A-I
\\
D-d-
OZ
,+
+.
W
'.e e
e-get '." -...,...
...s.
4, D d seaO'-
4 Ea Aus
==
hh-
$ aW9~e4 5
.J--
_v %pg. -
d.
u9 I?.
~
48
,.p s.g g.-.
y i 64 L -
ge*
3o
.. y. ". -.-
g l'
^
Y b.n.a.
j. ;
.~.a. -
1
. r ee
-[
" '+
C
,,;5 e-1
,c
- .g }
,,_.[
?'
' /.i ', - z
.+.
p 5
,. #. 1 -
. i *ygg
,d n.
,,m, gg + '
,,. g t
.n f
x
.v
.w..-.
..w n.
. -.. 3 gs g
m._, ;
.c --
?
f% ;'
, ?.)
n.
- 2 y
.,e
,h. ' w, :..
.u......,vn
.,..; M 4,
., s.
e.e
.M.
. [. i..(.'s] i.QQ 4
5 ~
- m$
[. '..
J.)%t zwA p
- 3., s %
V yqy
+
4 4:
- f.,
- a'
.s..
-. ~, L a /, @ **
.' ?, "1.-
e-
'Q ));l
_[",.
N
~
~.
r.
...s -
a
. ~r,is %..
t p k.&.
.c-e
.5 u u,-..
4,,
.e,.4,.
.g..
s@
- = '
- s 4 L.',. u.
... t au s
. m...
Y
.>l
- h....,,,
's' p
Av, ig,.'a.W@y,,W ?,. %,
. %.,z..
,, eg; l
Y.
? !:
N
. 0 ; A. l{. f..'
,.M-
- -._ :~.. ' ; r,, : l
? :I.
'I h'qp'h ):
QOf.hk k...
.f}. he&l..
.5 -j'
+K'.
. ~.. *, L;..
w **
i W K,,
W ant-l:
- ed.
- %_.n.s ev'.
~
T : : n:'y' st
- y.- P r' y:g ::c. 77 9.
- m. ty. e r,.
f * ;g% g f ( ~',4
.;dsj u L n l
.4Q-Y._
], *
-4,.,,,
[.
- ;.aQ _
z t'
&L_V,
. qy <
[.
\\
- ' ' Q... %. :..
'y..
3
' ' i
- n yeah a me* **+- +j+-
.y
+= #-<
,1
?,.,
= * *
-)
kf
?? a' :k A.'.
,. **Q
'_', ' _ Q &QVi Q'k ?
I af W..Q ;. -
.4
'.f.
?.
4
. r e.,. -
.+.p j
,sy.-
.. y.
.....,.s".
- ,..y
- p. 4
' h ', h
,.h M.:t*..hyht:[ h
$.b,:* 9'
.., f[
'N
.##V
? *.,.W, :..... 'c,f., *' c: ?,,-f '.,."'"4
' . ?..,gy-' V
..,.... ;.. '.. I d..i..:,. ',
. il/
.. y%.
g' [., ".'b,.? k..-..
t
- 2..
. e;
'#?
I glp {. _. %s'
- M l:,.4 *.= ;;
y, a.
, a.k. ; *.,.8 vy.. - -
.y s.
, j.
.[
'I =
'l
'. 5
.-\\..Q..
}
'e 4
.[
}
,l'.
I
.h
jtQ ?,..
_Q Q,;= "",, '.
,'.'(},' ' f* - }."frQh.;, W, ], ; p's z. '- g@ ~
- .; gs.
4 f.V
.' l2, f.
- ".-~.'r
.,: ~..,~.', l l*... >
- j
',..,*y,gyg, q;_.
s q
3
.; ;r _.
n.
,a y : _
6% 9.% HN. ".i-h;.y;.; 3d$ W %g.
4\\
. ;[. ~ WD
. ~g:
..M
) ' J.if
&T:, - *..l$ b.
- h.5,.. g.,
!.l.
k
? A. Y. *% )g(sY'
's ' A Y ] ...'1'
'h I'-. '-
^
.. ~3
- 4., - - g;
- v.
- n. w:q...,
-- n:
s
.a 6
W,$ *.j 'e. -.A
. 'gP, ' ' ;. h.1., ;. m.: 4,'N '
. - n[._@g
:E. V Q :v., %3,s.'.a '. /...: *W
- h j..-...-..c.s V'
.a.:*
,e_.~
.....L s
a ( 4 '. '. g, f $. =,.,a s" 3 g f '
{,'.( ^ ;.
.; ?.., L,,..y
.a &.. s, w :::,. \\; :.,.,., &, e*.
- (.. ~it.
y. G..-. ' f: -
R, W,hfg. p K. %.1 W.,'.
- ka G,.n ;. :
,'r.
k 3
s
~5. ;, '
'ei
~ r.p. g'.s 1_ M.. ". '.
,r,*'.-
s
' qW ?.*W' ?.< ].' : ','
- f/i.
- l s.
.:..+. n-1. '. *. 1...
'e w m.
a.:
.M
?
.t
~,.
g 2'.. 2 YU.. * : s,1.
a 1
W..?l$;,
a ;- - -
i
'f.y,
. ~, :y ' %..
.'e. M.
f"..
.'.l, fy y
T @tc{ C O A
g
~; [ 4 $ u %w, s :
l w?2 s
o r.
9 Q
y
$M - CO w
s A
,f-
..,,, j
....4
... ~ ;. E w'i.. -
-..- - e,..,,pyp map en de p..
I y.4~
4.
, 3
- .- vr c
A - power G - rod AC-2 M - steam flow of the drum' separator B - total reactivity H - rod AC-3 N - Trop (T-temperature)
C - pressure in the drum separator
. K - flow of the main 0-D - power circulation pump P-E - rod AC-1 (automatic control rod)
L - feed water flow 5 - water level in the drum separator l
ll 0
l
/l
},
l i
l l
l l
s 1
/
/
4-g
?
l D
/
1
[
I e
l 1,a l
I 4
4 ff
/
/
-WNa VD Y
L l
\\
l l \\
/
F"
\\" F l
\\
y
)
\\
/
\\
/
/
D WA l k
s s,y
'j jg
\\ y s'
Ar fu i \\ l
', l
/
i I
l i
i id y ya V
/W' I
i i
i i
i i
i
- nd of 12340*
Fault in measurement section of I
speration AZ.5 automatic regulators AR1, AR2 PK up over pressure in drum separator l
Triggering of f ast-acting steam-dump system 1
f ENVIRONMENTAL RELEASE TERMS IN THE CHERNOBYL ACCIDENT OVERVIEW THE SOVIETS HAVE DEVELOPED ESTIMATES FOR ENVIRONMENTAL RELEASES I
0F RADIONUCLIDES AS A FUNCTION OF TIME.
THE ESTIMATED RELEASE FRACTIONS APPEAR TO BE:
1)
CONSISTENT WITH THE S0VIET CONCEPTION OF THE ACCIDENT SCENARIO.
2)
CONSISTENT WITH MEASUREMENTS MADE IN OTHER COUNTRIES, i
h
._..m
__m.__
._m
.m
___m.
l n
- .*.*.g
-. ' +
.~
. y n
.g
..,.,'.:..a.
- s-r~
e a.
,e.
... +
.[
.i l
u e hf. ' '.9 ep-
' Q " ".. $...
L,.
',.4 ",.." m.
f
,y.
j i.
i
. - ~...
m l
,o c.. y,.9 c.-.
. a -.;..
2,,..
.....,,.. 'g ;^... ',.
4...3 g
~
m**
4 Y
)
t
. G.....N
.g' i
.) tr F
- l' *. $*u( ft a
etO " " '
,'"?
4.I,
- f *ft~.
3 7
'*.*.A 79' kj ' E.
.' m h: y.g-
_m rm d L. ":. W a * + *. ' '.{M s" 4 w
4,.
g% '.
. &a,.
t
'.. w:
a w c:;. : e.:.
W 8
n -.
.n.
f.
r 5.,
- ". f
,f.
,.i'.9,...
a : y.,$ 's s. :. s.g ' ^,, ~ -Gsp ~,W ' 4... : V :. C. 3.,.; y;,
- .. J... ; * '. y
- J r, y 4
...w.e i m. :.W u.M,.x.a e.2.. :..'.:,ec,.: 4, h'
.) '
' [,.
{' h
- x. u.,
I h."U [ O. i. i;b D M A,.)Q ' 44 ? Qv '. *' 4 i [ );..@ ; V Y.
w t
.. %., +.
I.
N ',,e 4
' i *J'. N. y'h..w. -
33
- ,s
.. d'.'h.' ' : 9.. t,%'),.
.-c'**
':, i. <.J.ta ".
"\\, hhp #s eg*8. (
+
II J..
.s
, s'St.
9
.V. k.L' y.4.% s.
s
- ea-e
.c' y...-.
_s:
y
+ -
y ~.
,s, f,
- ' y.,
b 4 K.
.t*
- g..
Vp~h. s...J $.
I p4&,...-. a_.,,.'. $: ;~ a.t, g,...
h so
- ^ -
y 2._.. r,
,4
.. s.: y ; V W
.. W.,.
m:;;r 4,.y p w,W V % Q. Q.WN *- '
~
=s L V_
'W'Rf.
- h.. '.. ' *'
Y.. ',Q.*. 5.. ;..
.9m
.s. %.+&,%
d r'
..\\'.*-
.e **A - A %
.., g e,
.~
p_.
e
, [
[ ', h.-
,, - *-.-.h;
,7 g'
- t. e " ' ' pg6
- p. '.( '
.s.
h,7 4-x;
.M A,.
< i',
3.-
Ay
%. te;dy *.;;,)g ; 'j; s..
h-y:,
O,r\\.
[!.,
o 94 h,ja.g _ Q%per.%
+
3 yc 4
3 e
?-
y <- :..i ~ k g
g >4 y..
y
.mk
,n W -n
.y
. am. w 4m. ~_y% w. Y M.b_
.g
.k %e.yy y,v a. A e.a J. e p e.
,w.__
., ~ ;, _,
i
$p,.e 7.b h. als.ct p, 7.q$WirM.-T N.re b w.r.e
-TM
~~
(
a..y I;
l <,'. ' :T -
.... y.' -.,...g
- .., w.
l v.
1-e o-g
.,g e.
y up
"[ - 9.
[.
M* h
- y ;a c.., p p ) 3 O uA;n:,y wan.y( W'g w=.:
A
^
n
. w^
r
... e s. h e c u,..
y
.~g w'..- Q....
Q. p p. :..
s.
+ u e '.
i e.
s.
\\
E N *-
.s l
4-
, w.y..n. ^-
p. y v. +.:. + bm. y.' ;
g4, -
. w c. G.,. ;-
W.c...,. -.s
,. y:.
....y L,, w s..
7
- p. Dg.;,.. -
r
...,9
.._e.v..
1.
kf.".LQ;I& ". 3..' g0.1 <.
Q e,
.i., :
p.e ~._
c.
-...g-t m.
M%sa n g%W ?.-f.g y,
e p
.e K ' '.
b
- M p*..q. c. Q e
em
~
m -:
y W. w T".,.
v-n.
. g. f y c A, e-i s
S w Q....
f.'g. 's.. g. *.. g e.. &.,;<; ; f~.<.1, %. -
_ =;
,Q,...
p."... >..- -.
y
, &.:..~ :,..
o
. g..m
~"',
_ n.;
- e..
~
}-
~ ',,,. (.,, T
' % 28 '" % 4
' 'l
.fi $ '~ '
- y Y
[ ".
.ij [ ~ } '. -
.g o-_ ;s
\\
['.g
. a[
.. -.....,,..'.".h,.'..
'l desb*.'
.. u.' '_,' :
,g.
WN. '
!. 4
~
4
.c
. 8 T[EP /'ci.. ! ' '%:. '? y x s;k.[
M..
w
.g 7.
- x.p.
s n /h h,x l
n._..
d_.
.. v.
~
O'
.. $ ~;4 D T. '. 8.
O.* ~..
S.
?-
t 1!
N.*N
..f
, '.Y l.4 Q.' :.,.'$
* ? ' M i
- 4. f _'
r
~-
c N~
.l y. -.
.e.
O se
.e.,.a er-m emme,o
... u
..r.e,.
vee...,...
.\\
,v
/ x- ~ +.
en.w.
..w
~
w I
i i
i i
l l
ESTIMATED RELEASES OF RADIONUCUDES FROM THE ACCIDENT UNIT OF CHERN0BYL NUCLEAR POWER PLANT
- 7....._...-....-...
_..._ m Released seNty, MCI Release l
Nuotdo poseslage by I
1 i
08.05.88". _ _.08.05A8_.. _
28.04.88 any be g to 100]
p.
._p _.
..a..
Xe-128 5
45 i
I Kr-66e 0.18 I
I 0.0 i
gr 85 I
l l
l-181 4.5 7A 20 I
l l
Te-182 4
1.8 15 g.
.. p Ca-184 0.15 0.5 10 l
Co-187 0.8 1
18 I
l Me-90 0.45 8
2A l
l l
Zr-95 0.45 8A 3.1 l
I Ru-108 0.8 8.2 19 p
. p.
Ru-106 0.2 1A 19 l
l Be-140 0.5 4J 5A I
l Co-141 0.4 18 2J l
l Co-144 0.45 14 2A l
l l
Pu 0.1.E. 8 __ _0.8E_.8 8A p..
.-288 Pu-189 0.1E-8 0.7E-8 8A l
Pu-240 0.2E-8 1E-8 8A Pu-241 0A2 0.14 8A l
Pu-142 0JE-8 2E-6 8A l
Co 242 0
11E 2 SA
._ _____.___ p.8E-2 Sr-se 0.25 2.2 4A 8r-90 0415 0.22 4A
__. Np-2_8_0,,
17
_ Q,,
8.2_ __
Estimated error
+ 50%.
Total release by May 8,1988.
DON 00E.V 7
SOVIET ESTIMATES OF THE CHERN0BYL SOURCE TERM ESTIMATED RELEASE TO ENVIRONMENT NOBLE GASES 50 MCI OTHER RAD 10NUCLIDES 50_ MG.L 100 MCI AVERAGE RELEASE FRACTION EXCLUDING NOBLE GASES 3.5%
ESTIMATED RELEASE FRACTIONS FOR KEY ELEMENTAL GROUPS N0BLE GASES UP TO 100%
IODINE 20%
TELLURIUM 10%
CESIUM 13%
INVOLATILE GROUPS 3 - 4%
PHASES OF RELEASE PHASE 1. APRIL 26 RELEASE ASSOCIATED WITH VERY HIGH FUEL TEMERATURES IN EXCURSION HIGH RELEASE OF VOLATILE FISSION PRODUCTS PHASE 2, APRIL 26 - MAY 2 REDUCED RATE OF RELEASE RELEASE PROPORTIONAL TO INITIAL INVENTORY OF FUEL (IMPLYING TRANSPORT AS FUEL PARTICLES) 9
~
,-~
e
~
n4 p-,e
-sa
--,,--.<--w n
y m
SOVIET ESTIMATES OF THE CHERNOBYL SOURCE TERM (CONT.)
PHASE 3. MAY 2 - MAY 9 INCREASED RELEASE OF RADIONUCLIDES, PARTICULARLY VOLATILE SPECIES IMPLIED HEATUP 0F CORE PHASE 4, MAY 10 -
RAPID DECREASE IN RELEASE OXIDATION OF U0 TO U 0 OBSERVED (MECHANISM FOR PRODUCING 2
38 FULE AEROSOLS)
/0
FIRE FIGHTING 3 TEAMS WENT TO SITE IMMEDIATELY FIRES LOCALIZED TO ROOFS BY 2:30 A.M.
FIRES QUENCHED BY 5:00 A.M.
OBJECTIVE WAS TO PREVENT SPREAD TO UNIT #3 PROTECT CABLE ROOMS OIL TANK ROOMS USED PRIMARILY WATER TO EXTINGUISH FIRES, FIRES WERE MAINLY ON SURFACE S0VIETS IDENTIFIED " FIRE-FIGHTING LESSONS LEARNED" LIST OF PROPOSALS GIVEN TO IAEA FOR CONSIDERATION 1/
e
- es. -
- t
.~
i r.,
l
.g g
l
=
}-
ff s.
- *E
,., f,*
f J
?
.i.
t
,,' s
}
w j.
o
+
7 q.').
f '..
',',;. 'p*
~
N -
-a s
4,
.r.d-
.,*ar~-
,d,.
,.-~
- U
.gr b. ]r g.,
a I
i s
.*Qe
'**9
..' g r
.,' Af
- gif
, tJ j-g
.. '. /
-l a#>.
s p
Yv'*'..'
-q
~
3.
e
- s o
. g
~,.
. ~,.
,s.~.
.p"\\'~;0x, p,
l
' d J*N*fq,...
- E
' }.Y '
'~~
n
.,.'s s,
,7 3.%
M* $:% i.O.;. ;n.j? d M, L
T;i ~ 2i.
4
~ y v 4:[.y gd. 4
\\,. e
,e
.s,.
. ^ g7,,n *h q*
?
s se _
., =
. * ;f' y
- ~
. V.
/
/
+
. g&;. 6 l
3
/
1 J.
., - e.
ff p
s
. -- y*a
.p r,
k
.;.IJ
. 1 J.'s
, P k r,
w
., y
.,..e r,. a-
.,,~;..
g, r
L.-
~r y-q$
^
V
, W
.9a r.
y g
A
+
g e-e l.
3
/
Q
- 1
,e
/
s,.*yr v
s
^
~s s.
~
c-l t.
t s
/
^
- f 4
{., (.
., p*
,~
se' es a.u,.
I.
m q.?.
r/
,q
< ~*
,/.
/,. j -
v.
?
F...
- ~~e y,.' h,
,(?~
t gy.
e f'
,,y. g
\\
,' ;f
.jr h
l t.
c e-4 s
.c l
-Qy r.,;A*W f
j
..&j.
b;;e..'
u
-.,.s
.h; e.
. 44
,'. an
..~.(
i,-
7.
g.-
t I
i
+ t*$.-
- ).-
>~
/
... j....
s 5 fr*%Chr J
(
t
ENTOMBMENT OF UNIT 4 A CONCRETE-WALLED BUILDING WILL BE CONSTRUCTED AROUND UNIT 4 TO ENSURE CONFINEMENT OF RADI0 ACTIVITY, AN INNER CONCRETE PARTITION WALL IN THE TURBINE HALL WILL SEPARATE THE THIRD AND FORTH UNITS, 1
A METAL PARTITION WALL WILL SEPARATE UNITS 2 AND 3.
A PROTECTIVE ROOF WILL C0VER THE TURBINE HALL, THE CENTRAL HALL AND OTHER REACTOR ROOMS WILL BE SEALED OFF.
CONCRETE WILL BE POURED OVER DEBRIS IN SOME AREAS, 13
l' l
ENTOMBMENT OF UNIT 4 (CONT)
CLOSED LOOP AND OPEN LOOP SYSTEMS WERE CONSIDERED.
i CLOSED LOOP SYSTEMS ARE MORE DESIREABLE FROM THE VIEWPOINT OF PUBLIC PERCEPTION.
AN OPEN LOOP SYSTEM WAS SELECTED BECAUSE:
PERMITS SIMPLIFIED CONTROL OF HYDR 0 GEN (DILUTION),
EASIER MONITORING AND MAINTENANCE.
A NEGATIVE PRESSURE DIFFERENTIAL WILL BE MAINTAINED BETWEEN THE EUILDING AND THE ENVIRONMENT, UNITS 1 AND 2 ARE EXPECTED TO RESUME OPERATION IN 1986, UNIT 3 WILL UNDERG0 A THOROUGH SAFETY REVIEW BEFORE RESUMING OPERATION,
/9/
6 4
1 i
4 s
I l
OEit4MIA BMA 3AXOF30HEHb1M e 4 E d.IJi' /\\
i i
e
\\
l t
l
- i l
l l
g.
'Q h*
ff T t" * ' ' ' V 3
. %d..
.s
. o 3
i l
l e,
a ei et 1
6
^
s s
l i
l[;
4 PROPOSED RBMK-1000 MODIFICATIONS (SHORT AND LONGER TERM)
CONTROL RODS PERMANENTLY INSERTED IN THE CORE TO A DEPTH OF 1,2M.
ABSORBER-TYPE CONTROL RODS ALWAYS PRESENT IN THE CORE WILL BE INCREASED TO 80, TO FURTHER REDUCE THE POSITIVE VOID COEFFICIENT (BY A FACTOR OF 2); TEMPORARY MEASURE UNTIL FUEL ENRICHMENT IS INCREASED TO 2.4% FROM THE PRESENT 2.0%,
ADDITIONAL INDICATORS OF THE CAVITATION OF THE MCPS WILL BE INSTALLED.
AUTOMATIC CALCULATION OF REACTIVITY WITH EMERGENCY SHUTDOWN SIGNAL WHEN EXCESS REACTIVITY MARGIN <C SPECIFIED LEVEL.
(
ORGANIZATIONAL STEPS TO REINFORCE TECHNOLOGICAi. DISCIPLINE AND TO IMPROVE QUALITY OF OPERATIONS, EVALUATE ADDITIONAL DIVERSE AND FAST ACTING ABSORBERS SUCH AS LIQUID, GAS, OR SOLID FOR FUTURE USE.
.i__--.s-i.sa.-44---
s e.L a.m
_mA-.--
._...____.2,
.,;;a_,_.
.._.-._,_,,_____;_m
.a__,,
s 1
v. -.
.n.,
..s.
., 7 g.
4,.
s n
l
,~
f.
.g
,a.g. 4 g *,
L,...=
A h -
.r ft a
. 7; i
.. p
.J.
m
~
g g
, '.,.4g. '. - *..
..o f
'., +
?,s.
'.'f+:Oj
- O g
.M 4 9
^
(+
,A
.f hhh{
. e.,
9Jt.
~
w m.-
g 4.~h
.' > b.-
c,'.. + +....
RA+MXiad.,.Y.,
W k T.M
i
'la
'. ' i i
r -
, :.y 9
- y
..,,....t
.. (". p h
,I
%..,J4~
".;.1,.s n.
.. a.
.w.
.f
.hh..~.
h.k@
.. Q,,
WWM MJ:
O..pMS.WW %
x';'t F1 $ i e a T.;
a r.% W 3
l
..w.a.
f.
.a.x
.e.
e.g
(:g:p..; :3 y y..
_,.:.3 g.
.(
9 p
l n,fm4_.,. wg :
.m.. x,Q 4
.. 4, -
- m. 3 w.ne..x..... n..
1 w.
.h, l:h k '
- vi s e
,e.
. ~h,k. 5 )
.. k.
.y
~ b.
+. ' k, h' g;
n_.
.w
.n Y.
h.h-5
, nrm I%.,. N b.
'**4Y*
fQ'
}
h.%ys.
s y
y t
. m 4,.
. E i.,3
+
' n.*.
. g f.y, ^g v.
.... ' 41.g i ;
i R.,
i
^
.. + -
4,.&. y s n 9.,..
y'p:,.
g...g.
. ~..
l
. 'g.,
,e,-
c 4.. i
..f A,,
3
.. :,. =v
,.x, 1y.,.
4s
- f.. :
- 3. >. :~g.. '1 s.
vb-I g
,. y We+ t;..'
9.. ~ ' s[qi,.,
l
,C.
. s.t
'; 4' }.,e.:r'. c. '.c f h
,. $u
~,.,, f,.} ' ' ?.y.
fF 's-
,gL '
f I
.. kik
-v..
w'
, ~.
.. a q:,. y y..
q-w.
. e...
..a a.
4 1 -.
' '. Y I"
- l,).
., b$
i
.. ~ -
.~
'. a -
'* b'$
j k
- N'T #
.6
.~ ogi k
.v. !
.j'f l g * '. a. '.. :-J.,
's.f
- rc
"L
$. },,'
h l*,
j.
~.
ca.a; n} n,..
- n. ;.~. m'..
- e. ;.; '.
. r
.n-%nt W
.'I l
9,. ;. s.
..r..'..g h
..f-. ' /,* ; tw g ' J, '
- 40.., p*
A*-
",.s x.
r g'
<a
- *.'j,. -
_'j;.'Q'Y,....
'O,-, ['
q
,,,4 a f,
.' -. i,.
e
.8) f
'J' lRe. g >l } p '
l
. ci *.
- i '.)_
- =
(*
_ _i
,.y; 9
. y.
. f. - _.., '
+
.c
~
i n.
y
^ f: ; ' ;,.
, 4flCQ yR.l,g,; Q
.l
- a *y $.' _ " w t
.3 e
k.
- g. 3,;,,n..
,s _ - c 7...
p 4, f f..-y. :.s 9. p 9,..,
y y....
y i
,..:. p..c y
...t t.,.
l
,,.(i i{ f" *. I.
0..
. f.l*tf%f M t l
b* g
,4:,-
m,; ;) g,.,
- " {
s k
,? g.
.pf y a ~::' i O :;.h j -
..:p.'
h
, (,.. i L
.i
- r. Y _ g,, ' 6g.
4..
.P..
v, y - 4 @ h'W. m,. 4 }l,, %. _.
g :..; ' q L 1 gS.c
$ s, / y?jf.,g,.. ;M,,.
g 3.,, 9.f,.u e, y},N. g,. 7 i. g,4...
.. t g%. ". <
.cif..v;.
j
,t.i g
[,
g..g! -.
l 3
u.[ %
d.
['*,,
'3. ;.
h.y a'.
'E.'.
'.. i, e,w..:..
..,s.
y
.<T( '
r
.. w.. g..,
.i.9g4 4
.s.,..
p.spc..v.+.,
.a
'M.-.,
,!. K.
p
1
- c.
,.N; sW.
by )..
g'.f 7 l
--,)$. ', ~. 3:. j.: <. m.... ' y;[
g.
.. '..? P p 4-% < 9. s 9
,. y t
, - s.". r e.
. t ' w..
p.
,. m
- *:.m
/*.
< : ', %.., *. O, p. ' - -
s
..g..
-.. p r.-
ry :. s 4 :mr..
s
-av.
{
~. (.. -
i
.,g. w
.r.
.g...
..O bA b
'*e S/$" kf '#th
'5' c l y:s, ' * "
~
.~..
6
. k
, +
a p
i i
I.
_e__a--_.
h-,i
,.a..aa.__aJ
-a.
u m.a 4__.
e sII.
- 3. -j..
e..
-..... s.
r.
y,e,.
,w.
.*q
. A s.
m
'- e9 **
s.
_b 4,.
t.'. e f. gd...Q @ 7. *fA..'17 ;'.
. W. l :1 E...i J..'.f; z.,'.gpg. g.. '
3
..l
- F:.
h.
i/ s
}
3.... -
,...nt,, e..... y ;>
,,,.. g
) q...,7,. r-...,.. g* y [ y,.
+.
.~4
,. +.<>.
e,
1
.s t'
o '....
' ' c ., c.i.
e y
A FL."'
s A., ; L. ;.* f*,y, 3 - --
t *,.** {.' &M.. ' '.. ; Y t'
^
4"g
.. '.. _...,' g ?4~.
.,: 4
?..
.:-;p~.
~y h -s'.
=...
..,..,..E
.,.,,e-,.
..',q;...y..
i
- g i
.y-j j
e..
l e# 9 v
... n..
~
y U.
M w..
~
u,.
I
..l
.a 5
.-. -,. - g i
4 1
's'.'
[
,g_
$& ?
....,,4/* W-
.JQ& f :.. p
.l.< W
\\
I s.~
- 7. y. w. g.,.....,...
. - g._
_.-,7~..
g
......_p.,y'g
~
' ' ' g
l
(,
1
[
Q am If):
L.,e O, U5.-
<<.- q q 4 s..~.,
I....,....- ',
z
,.,h 4.
i we emy,'
-ea w.y a
.4.'u men.4..
'.O me
.6
....a a
+
~ '. ' -
e a
g., v.,.,
p
,...,p.
.'.b..,
y.le..
. ~. %.
....X&.. -
,$ y,.. '.
- I h
i 4
y.
l
,,-l.
.. f r, I
I i
==
, =...-...,,,ii f.
v.L. fed -eg
,.k,,,.,
,..m
- w.. = #
f.
s
'h 4
1t. [ f *. 7
- f.,
.s J,'..-
g?,
'e
' ')
~
Rh '. T ) y o ~ ' K ~} 2,n..........,_'w..% ~ ' '. f..
_,.~
.,y$.ny (QQRyi b '
.,. p af,
.,,, e. m e. _
s.
h.M.. ' *$ 8$' " T1*T $7,TJ*fPU.U?.,
y
, fMT.Z**" + g.17@;- J '
5, y,.,4 n..
- w,
-m
.. e.. y y
' b 1 *.! kit * ". k'kF *o o.<g
'~.. M T M g.'.t.
.,1
. ;., h, d/ ji 1 i
-aq.
6
., ;.,... g. s...g,
- 7. y
..., yv.v.+,3..
),.
- 4
- - +
,4.- 4 3p..,
g..
s q.
. rs. -
i ~,1. ! $
'.s' '7?
.hs.1 ~ ' T
..k. \\
..i 1,sM..
J'
> {.... '.
4
,s
~
sy
' v Lf..
w v.m..,3 p.
1 -.
Sg.
- m. + s.s.w.s.
-....n. 4 %,a
.,e.
..e.
..n....,
m, g3 s
3.,,.
..y w.
~
....,.M-
-;c-.. - QW
.p f..
.. u...y -
. p W. -. * *.
5-m,..- >
e ;w,y
. : - -' ? -
.*d W,, - ed.,
e,*..
v knr -.
.9 m ma
.h k C.~ d i 1.4
(,'"
J
'i.'..av..
k'
. a...n w,.,..
.w.
. m.s 1 4 e.,..r.
.v.
i..
.w.'
..t u.. ~
@w
,7.,
s a.,,,,4@
4..
+
sw. ~
.-u,..
.ar........
a n
g
.g s.+.
- '. [ '+#
,v',
i' "# [ ~ I
[
, f
'l (
~
, x =. -
+;
<.. Sp, g p m 's '--.
's,eqq n.-
.- s c it
OF THAT GROUP, 35 PEOPLE EXCEEDED 400 REM UP TO A MAXIMUM OF 1200-1600 REM l
4 Table 7.2.1 Estimated doso, of I
' lic exposure in some populated i
areas in te.o 30 km - zone arround ChNPS l
Distance D -[ '
!*oso Doso on Dose f rom Radioactive Settlement f rom rato on f rom child's follout in 7 days R ChNPS "D"i15 d:. charge thyroid km mF: 'li
. 'oud R rom estimate octual Chistowka 5.5 17 10 120 8.4 3.2 i
Lovlev 9
25 250 17 10 Ch e rno byl 16 8
1.2 80 S.6 3.0 Rudki 22 8
G BO S.6 2.2 Crovichi 29 2.5 0. ".'
25 1.8 4.4 ll/$ IDIE:
SEVERAL OTHER C0ftHJiI'-
r00LD i:?VE EXPERIEllCED DOSES (INDIVIDUAL) OF 30JO RFN.
l
\\d
6 T s ble 7.2.3 ESTIMATED C' T LECTIVE DOSES OF EXTERNAL IRRADIATION O J: TI'E EVACUATED POPULATION AREA AROUND NUMIT'iR OI: POPULATION COLLECTIVE DOSE CH NPS fl'OUS AND/ MEN MLN. MEN. REM T. PRIPYAT d 'i O,15 3 - 7 km
/,0 O,38 7 - 10 km it,O O,41 10 - 15 km 0,2 O,29 15 - 20 km 11,8 0,08 20 - 25 km 14.9 O,09 25 - 30 km 39.2 O,18 TOTAL 105 1,8 CliERNODYl2CS h
DOSE TO AN INDl":1. 'I. Fr! N USE OF CQNTAMINATED FOOD FOR.0NE MONTil FOOD TYPE DOSE l
LEAFY Vr.r Anl.E 40 MILLIREM j
EAT 20 - 200 MILLIREM MILK 2 REM (ADULT THYROID) 5 REM (CHILD THYROID) 1.
ASSUMING UI- 0F 10 DUE 18' NSHIt;G I
l
i l
i l
Tnble 7.2.9
)
PREDICTED F JES OF THE EXTERNAL EXPOSURE i
POPULATION ETJ SOP 4E REGIONS OF THE USSR l
EUGOPEAN PART i
1 3
POPUIRJON 0035 POR 1988 O
OTTVE DOSE REGION MILL l" < NS REM / YEAR 10 MAN
- REM i(URAL URBAN FOR 1988 FOR 50 YRS i
UKR.SSR CENTR.
1 . ',
0.270 0.150 2.750 9.31 i
UKR.SSR WEST tut 0.067 0.038 0.440 1.47 UKR.SSR EAST 14 -
0.077 0.041 0.750 2.52 UKR.SSR SOUTH 1-74 0.045 0.024 0.730 2.47 BSSR SOUTH-EAST O.980 0.520 2.050 6.94 l
BSSR NORTH-WEST 7.**
O.094 0.050 0.470 1.55 j
MOLDAVIA 4.1 0.084 0.045 0.270 0.92 l
BRYANSKAYA REG.
1.4 0.500 0.270 0.440 1.49 i
)'
KAUNINGR. REG.
0.9
~
O.012 0.003 0.006 0.02 KALUJ..TULSK.
]
SMOL REG.
O.120 0.064 0.320 1.08 O
1.17
- . ?
0.140 O.075
.3 50 UPg3K. REG. __
8.8 29.0
___i 1_
_]
TOTAL 74' i
l CHf74740trMC5
SUrtH/.RY OF GENERAL POPULATION COLLEC11VE DOSES & ASSOCIATED ESTIMATED i
HEALTH EFFECTS i
PATHWAY NO. OF EXPOSED PEOPLE COLLECTIVE DOSE 6
l EXTERNAL DOSE 135,000 1.6 x 10 PERSON-REM l
EXTERNAL DOSE 74,500,000 29 X 106
)
FOOD PATHWAY - CS UNSPECIFIED 210 X 106 THYROID EXPOSURE UNSPECIFIED
' SOVIETS STATED THIS NUMBER IS CONSERVATIVE BY AS MUCH AS A FACTOR OF 10
(
)
i l
i l
i
s 4
EV.ERGENCY RESPONSE MEASURES TAKEN IMMEDIATELY AFTER ACCIDENT PRIPYAT POPULATION (45,000) ADVISED TO REMAIN INDOOR AND CLOSE WINDOWS ON APRIL 26 OPEN-AIR ACTIVITIES BANNED AT ALL KINDERGARDENS, AND SCHOOLS; IODINE PROPHYLATIC TREATMENT GIVEN THERE EVACUATION OF PRIPYAT BEGAN AT 2 PM ON APRIL 27 AS DOSE RATE WORSENED; COMPLETED BY 5 PM THE SAME DAY REMAINING POPULATION (90,000) FROM 30-KM ZONE EVACUATED IN NEXT FEW DAYS BECAUSE OF CONTINUING CONTAMINATION DUE TO CHANGING PLUME DIRECTION CONSUMPTION OF MILK CONTAINING 1 X 10-7 CI/L OR MORE OF l-131 WAS BANNED ALL CHILDREN FROM 30-KM ZONE WERE SENT TO SUMMER SANITORIUM IN THE COUNTRY
q 4
/
EMERGENCY REPONSE MEASURES TAKEN (CONT.)
STANDARDS FOR PERMISSIBLE LEVELS OF CONTAMINATION IN FOOD PRODUCTS ISSUED BEGINNING EARLY IN MAY 1986 1240 DOCTORS, 920 NURSES AND SEVERAL THOUSAND SUPPORTING ASSISTANTS MOBILIZED TO PROVIDE
' MEDICAL CARE OF EVACUEES EACH EVACUEE EXAMINED; BLOOD TESTS CARRIED OUT; IN SOME CASES EXAMINATION AND TESTS REPEATED EVACUEES WHO SHOWED IRREGULARITIES WERE HOSPITALIZED IN SPECIAL SECTIONS SET-UP AT CENTRAL REG IONAL HOSPITALS i
LONG-TERM PROGRAMS ARE BEING ESTABLISHED FOR MEDICAL AND BILOGICAL MONITORING OF POPULATION AND PERSONNEL i
4 4
DECONTAMINATION--OFFSITE BUILDING AND HOUSES ARE BEING DECONTAMINATED BY SPRAYING DECONTAMINATION SOLUTION AFTER WASHING, CONTAMINATED SOIL AROUND THE BUILDINGS TURNED OVER OR REMOVED WITH BULL-DOZERS AND TAKEN AWAY TRANSPORT VEHICLES DECONTAMINATED USING
~
SOLUTIONS BY SPRAYING AND STEAM JETS.
LONG iERM DECONTAMINATION PROCEDURES OF THE ENVIRONMENT ARE BEING RESEARCHED 30
1 s
DECONTAMINATION -- PLANTSITE THE SITE, THE TURBINE BUILDING ROOF AND THE SIDES OF THE ROADS TREATED WITH RAPID POLYMERIZING SOLUTIONS TO REINFORCE UPPER LAYERS OF SOIL AND PREVENT DUST FORMATION.
THE NUCLEAR POWER PLANT SITE WAS DIVIDED INTO ZONES FOR THE PURPOSES OF DECONTAMINATION.
DECONTAMINATION IN EACH ZONE CARRIED oui IN THE FOLLOWING ORDER:
REMOVAL OF DEBRIS AND CONTAMINATED EQUIPMENT FROM SITE; DECONTAMINATION OF ROOFS AND EXTERNAL SURFACES OF BUILDING; REMOVAL OF A SOIL LAYER, 5-10 CM THICK, AND TRANSPORTATION TO REPOSITORIES; LAYING, WHERE NECESSARY, OF CONCRETE SLABS OR FILLING IN WITH CLEAN SOIL; COVERING OF SLABS AND NON-CONCRETED PARTS OF SITE WITH FILM-FORMING MATERIAL; ACCESS RESTRICTION TO THE TREATED SITE
%\\
r 4/
1 2
REPORTER'S CERTIFICATE 3
4 This is to certify that the attached events of a 5
meeting of the U.S. Nuclear Regulatory Commission entitled:
6 7
TITLE OF MEETING:
Briefing on IAEA Chernobyl Meeting (Public Meeting) 8 PLACE OF MEETING:,
Washington, D.C.
9 DATE OF MEETING:
Wednesday, September 3, 1986 10 11 were held as herein appears, and that this is the original 12 transcript thereof for the file of the Commission taken
.f-13 stenographically by me, thereafter reduced to typewriting by 14 me or under the direction of the court reporting company, and 15 that the transcript is a true and accurate record of the 16 foregoing events.
l 18 s-Mar $lynn M.
Nations i
19 l
80 21 i
1 22 Ann Riley & Associates, Ltd.
83
~
24 25
,_-.,___..-._.__._.__....,,-.-__,_-mr.,
y_
,_,,.. _ ~
,h NNNNNNNNhhhh&kkk&&&f 1
5 TRANSMITTAL T0:
X Document Control Desk, 016 Phillips ADVANCED COPY T0:
The Public Document Room DATE:
Cl Is glo n
FROM:
SECY Correspondence & Records Branch Ij:
Attached are copies of a Commission meeting transcript and related meeting l
document (s). They are being forwarded for entry on the Daily Accession List and placement in the Public Document Room. No other distribution is requested or l
required.
I AS A b unobu[
kehna Meeting Title 3 r t (la on 3
l J
Meeting Date:
9/3lt6 Open X
Closed Ill' Item Description *:
Copies Advanced DCS
%)
,8 to PDR Cg
- 1. TRANSCRIPT 1
1 l
e./u<berwks l
3
=>
2.
3
_~
-c l:s; I
- g;:
i :ii:
3.
g I
c=w
\\h 4.
e E!E 8-s e
a 6.
9
- PDR is advanced one copy of each document, two of each SECY paper.
C&R Branch files the original transcript, with attachments, without SECY papers.
g j-(w eene me m e me m w w ein n m w a m % m m M
-.