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UNITED STATES OF AMERICA
NUCLEAR REGULATORY COMMISSION
***
BRIEFING ON ANNEALING DEMONSTRATION PROJECT
***
PUBLIC MEETING
***
Nuclear Regulatory Commission
Room 1F-16
11555 Rockville Pike
Rockville, Maryland
Tuesday, August 27, 1996
The Commission met in open session, pursuant to
notice, at 2:05 p.m., the Honorable SHIRLEY A. JACKSON,
Chairman of the Commission, presiding.
COMMISSIONERS PRESENT:
SHIRLEY A. JACKSON, Chairman of the Commission
KENNETH C. ROGERS, Member of the Commission
GRETA J. DICUS, Member of the Commission
NILS J. DIAZ, Member of the Commission
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STAFF AND PRESENTERS SEATED AT THE COMMISSION TABLE:
JOHN C. HOYLE, Secretary
KAREN D. CYR, Deputy General Counsel
RAY ART, ASME
DOUGLAS CHAPIN, Principal Officer, MPR Associates
STERLING FRANKS, DOE
DENNIS HARRISON, DOE
DAVID HOWELL, Westinghouse
DEBORAH JACKSON, Materials Engineering Branch,
RES
MICHAEL MAYFIELD, Chief, Materials Engineering
Branch, RES
DAVID MORRISON, Director, Office of Nuclear
Regulatory Research
JACK STROSNIDER, Chief, Materials and Chemical
Engineering Branch, NRR
WILLIAM RUSSELL, Director, NRR
JAMES TAYLOR, EDO
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P R O C E E D I N G S
[2:05 p.m.]
CHAIRMAN JACKSON: Well, good afternoon, ladies
and gentlemen. The purpose of this meeting is for the NRC
staff and Department of Energy representatives to brief the
Commission on the Marble Hill and Midland annealing
demonstration projects as well as other annealing program
activities.
This cooperative effort between the NRC, the
Department of Energy and the industry is being conducted to
evaluate the engineering materials and regulatory issues
associated with annealing in the United States. The program
provides for the sharing of information gained by technical
experts in the United States as well as that gain from
annealing performed on Russian-designed reactors.
In July of this year, the first annealing on a
United States commercial reactor pressure vessel was
performed as part of the Marble Hill program. Therefore, I
believe it is especially appropriate for us to be discussing
the overall progress of the annealing program at this time.
We look forward to your presentations.
I understand that copies of the presentation
slides are available at the entrance to the meeting and I
understand further that we will have a three-shift
presentation; is that correct?
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MR. TAYLOR: That's right.
CHAIRMAN JACKSON: Unless there are any other
comments, Mr. Taylor, please begin.
MR. TAYLOR: Good afternoon.
With me at the table from the staff, Dave
Morrison, Bill Russell and Mike Mayfield. To my right,
Sterling Franks and Dennis Harrison from the Department of
Energy.
As you noted, Chairman, this will be somewhat
unusual in that we will have representatives from several
organizations who will be participating. The staff will
first provide some general background information on the
annealing demonstration program from the NRC perspective.
We will then turn the briefing over to Mr. Franks and his
people to describe the Department of Energy's program.
At the conclusion of their presentation, the staff
will return to the table to provide you further perspectives
and the status of plants for the annealing demonstration of
the Palisades vessel, ultimately, we hope. Not the
demonstration, that's Midland, but the actual leading up for
the annealing of the Palisades vessel.
Before starting the presentation, I would like to
note that this project has been of significant personal
interest to me. Since we promulgated the thermal annealing
rule, I felt it was very important to demonstrate the
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engineering feasibility of thermal annealing for U.S.-
designed reactor vessels. I was very pleased when the
Department of Energy initiated this program, worked with the
staff at DOE and Terry Lash in implementing the memorandum
of understanding which we signed between DOE and NRC by
which we were able to participate in this annealing
demonstration.
I feel this program is a very important step in
the process of demonstrating thermal annealing as a viable
option for assuring the integrity and safety of U.S. reactor
pressure vessels. I want to congratulate and thank DOE and
the industry for taking the initiative in performing this
program.
Mike Mayfield from the Office of Research will
continue the introductory part of the program.
MR. MAYFIELD: Good afternoon.
The NRC's regulations and regulatory guidance
contain considerable information and devote considerable
attention to assuring the integrity of the reactor pressure
vessel. However, as you know, the pressure vessel,
particularly in the belt line region, is subjected to
neutron irradiation which brings about long-term
embrittlement, reduction in fracture toughness and reduction
in ductility of the materials.
Now the problem that brings about is it makes the
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pressure vessels more vulnerable to failure under both
normal operating conditions and accident conditions such as
pressurized thermal shock.
The regulations impose limits on normal operating
conditions, the pressure and temperature limits, as well as
limits on the level of embrittlement for the reactor
pressure vessel. The focus is to assure the safety of the
pressure vessel. However, this can effectively limit the
operating life for plants.
Thermal annealing is the only known method for
mitigating the effects of neutron irradiation.
If I could have the next slide, please?
[Slide.]
MR. MAYFIELD: Thermal annealing is simply a
process whereby the belt line region of the reactor pressure
vessel is heated to a temperature above the normal operating
temperature and held there for a period of time. Typically
we talk in terms of a one-week period as the hold time.
The -- by elevating the temperature, you are reducing the
effects of the neutron irradiation, you restore the
ductility and the fracture toughness. The major differences
or the major contributors to the level of reduction of
embrittlement are the difference between the annealing
temperature and the normal operating temperature and the
hold time, those are the key variables that we are concerned
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with.
Now, as was noted, the first annealing of a
commercial reactor in the United States is scheduled for
1998. We have in anticipation of that promulgated a
regulation and a regulatory guide addressing thermal
annealing. Both of those documents address both the
material considerations and the engineering issues
associated with thermal annealing.
If I could have the next slide, please?
[Slide.]
MR. MAYFIELD: While we haven't annealed reactor
pressure vessels in the United States, there is considerable
experience with annealing the Russian-designed VVER 440
reactors. In fact, they have now successfully performed 15
annealings on 14 different vessels. The Novovoronezh Unit 3
was annealed twice. The first time, they didn't anneal it
at a sufficiently high temperature to get the recovery they
wanted to sustain continued operation so they went back and
did it a second time at a higher temperature.
The NRC had a team on site to witness the second
annealing of the Novovoronezh Unit 3 and it was in 1991.
And we had a team on site to witness the recent annealing at
the Loviisa plant in Finland.
We have been actively involved with the Russians
through the Working Group 3 of the JCCNRS where we have had
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an opportunity to look in detail at the materials issues,
the way those materials embrittled as well as the recovery
and re-embrittlement estimates they have for their plants.
With all of this information and while it has been
very useful, it doesn't address all of the issues,
particularly the engineering issues, for U.S.-designed
reactor pressure vessels.
If I could have the next slide, please?
[Slide.]
MR. MAYFIELD: As you can see on this slide, there
are substantive differences in the design of the VVER 440
vessel compared to a typical U.S. design. This drawing on
the left side is for the Palisades reactor vessel. You can
see that the Russian vessels are longer, the wall is thinner
and they are only concerned with heating one circumferential
weld whereas, for many of the considerations in the U.S., we
are talking about heating the full belt line region because
the limiting materials typically would be an axial weld for
U.S. designs.
So the Russians have a somewhat less onerous
problem in terms of deformation of the vessel. We are
concerned with the U.S. designs because you are heating a
longer region, you are getting more deformation in the
vessel in general, more bending moment in the nozzle region
and potentially more distortion of the flange.
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So while the Russian and East European experience
has been useful, it didn't address all of the engineering
issues.
If I can have the next slide, please?
[Slide.]
MR. MAYFIELD: We felt that it was important to
find a way to address those engineering issues. While the
vessel was of significant concern, we were also concerned
about potential for heating the concrete and the biological
shield wall, potential for overheating the embedments in the
concrete that support the vessel.
So when DOE structured their program to evaluate
annealing, we were quite pleased to see that they were
addressing engineering issues, materials issues and
regulatory issues. However, the staff's primary interest
was in the annealing demonstration -- I'm sorry in the
engineering issues associated with their demonstration
program. We have had, and continue to have, an ongoing
dialogue with DOE and their contractors relating to the
materials issues so we felt like the big uncertainty in the
scheme of things was on the engineering issues and that was
on the portion of the program that we addressed in the
memorandum of understanding.
CHAIRMAN JACKSON: Now what you refer to as the
engineering issues, are they the ones that are in some sense
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embodied in what you highlighted as the differences, in some
sense, between the Palisades and the VVER, the kinds of
considerations one has to have?
MR. MAYFIELD: Yes, ma'am. We are particularly
interested in looking at demonstrations of how the vessel
would behave, deformation, any permanent deformation in the
vessel or the piping, concrete temperatures.
CHAIRMAN JACKSON: And by "materials" you mean
restoration of the properties; is that correct?
MR. MAYFIELD: Yes, ma'am, restoration of the
properties as well as re-embrittlement trends.
CHAIRMAN JACKSON: All right.
MR. MAYFIELD: If I could have the next slide,
please?
[Slide.]
MR. MAYFIELD: As Mr. Taylor noted, the NRC is
participating with the Department of Energy through a
memorandum of understanding on addressing our participation
in this program. Because we were sure the licensees would
be referencing the reports from the DOE program, we felt
like we needed to clearly define the scope and nature of the
staff's interaction with the Department of Energy in this
activity. We needed to make sure we retained our
independence as we were looking at what was going on in the
demonstration and, at the same time, we wanted to make sure
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we got as much information as we possibly could, so we
needed to be as close -- as closely involved in the program
as was practical and at the same time maintain some
independence.
So through the memorandum of understanding we are
performing an independent review and evaluation of their
demonstration projects looking both at the Marble Hill
demonstration that you will hear more about this afternoon
and the Midland demonstration that is coming up in the fall.
We are performing independent validation analyses,
both thermal and stress analysis before the demonstration
looking at the design of the heaters, the design of the
heat-up and cool-down rates, we have installed some
confirmatory instrumentation on certainly at Marble Hill and
we are looking at instrumentation to put on the Midland
plant.
We will look at our independent measurements and
compare those with the measurements made through the
Department of Energy measurement program and then we will
also, as warranted, perform post-annealing validation
analyses looking at both thermal and stress analyses to make
sure that we understand what has gone on during the
demonstration and to validate the analyses that were
performed in designing the demonstrations.
So our focus, again, has been to get as much
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information as we could possibly get out of these
demonstrations.
If there are no other questions, I would like to
turn this thing to Mr. Franks and the DOE contingent.
CHAIRMAN JACKSON: At some point, perhaps, you
might, before it is all done, you mentioned that you thought
the materials issues in some sense were easier to deal with.
MR. MAYFIELD: I didn't mean to imply that.
CHAIRMAN JACKSON: Okay.
MR. MAYFIELD: We have an ongoing dialogue on that
issue. I didn't mean to imply they are easier to deal with.
DR. MORRISON: A different department.
CHAIRMAN JACKSON: It's not your job description,
right?
MR. MAYFIELD: It unfortunately is in my job
description; I just didn't mean to imply they are easier.
Just we are talking about those issues.
CHAIRMAN JACKSON: Okay, thanks.
MR. MAYFIELD: Mr. Franks.
MR. FRANKS: Thank you.
Chairman Jackson and Commissioners, I am pleased
to have the opportunity to come and describe our program to
you today and will look forward to letting the vendors do
the talking but I want to also mention the kind words that
we received from the NRC flow both ways.
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We have the utmost respect and regard for the way
the program has been conducted to date. The relationship
that was formed with this MOU clearly demonstrates that we
can do companion R&D; and a mutual goal without a lack of
confidence or trust and still maintain the arm's length
distance that we need to from a regulatory standpoint.
So, Mr. Taylor and Mr. Lash certainly challenged
Dave Morrison and myself to establish the flagship program
that I hope you are going to be interested in hearing about
today.
With that in mind, I want to mention a couple of
points about it from a DOE perspective. Clearly, the NRC
has recognized as well as some of the -- as well as the
Department of Energy the importance of conducting this
annealing demonstration. However, not as many people within
the country shared our enthusiasm about the need for the
demonstration.
With the turnout I see today, if we can get that
kind of information out to our stakeholders and demonstrate
that we are sincere and that this is going to be a viable
component to an energy strategy to maintain our existing
fleet, that would be helpful.
With that aside, another key component that is
embodied in this program is not only is this a U.S. program
but, as mentioned, we are relying on Russian information
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technologies but, as well, we are trying to make sure that
the rest of the world watches our demonstration because it
will be unique and different than what has been done in the
past. It is significantly larger and significantly more
complex. So, with that in mind, I would like to go into
some of the key areas of information that we felt like we
needed to demonstrate.
First slide, please?
[Slide.]
MR. FRANKS: I don't want to read these to you but
I want to give you the sense of these.
In designing the program, one of the key elements
of that was, with the sizes we're dealing with, will we be
able to maintain and regulate a heat source that would
elevate the temperatures and maintain those temperatures at
an elevated condition until such time as the annealing
occurred?
Also in doing an in situ test, would we be able to
demonstrate that the overall integrated plant, reactor
coolant system plant, would respond in a manner that would
require us to -- would allow us to not have to disassemble
the plant in some fashion but to allow us to go ahead and
heat it up and demonstrate an integrated plant response to
the annealing to assure that there was no damage.
Additionally, we wanted to make sure that our
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computer codes and models adequately described the process
and that they were accurate in terms of supporting our
analytical techniques.
Why did we choose two technologies? When we first
started down this path, we recognized several risks in
trying to come up with this large-scale demonstration. One
of them was the uncertainty and risk and concern with the
utilities. The other was from an actual component
standpoint with this large device, heating device, would we
be able to do the anneal to the point we wanted to.
I didn't feel comfortable and neither did
Mr. Taylor or Dr. Lash so we sold the program on a two-
pronged approach, looking at two different technologies, one
to allow that if one were to not accomplish the desired
objectives that we would have two chances at it. Secondly,
as equally important to me, was that both of them would be
successful and then we would have a mechanism for
competition and I think that is very important as we go
forward looking at potentially 30 plus plants that might
employ this technique.
Additionally, we wanted to take this time to
document the lessons learned in doing the demonstration so
that we could consider ALARA considerations, maintenance
considerations in the lead plants and try to take into
account the lessons we learned on the nonirradiated vessel
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and then apply those on an irradiated vessel.
With that in mind, I would like to turn it over to
Dennis Harrison to introduce our program participants.
MR. HARRISON: Good afternoon.
Before I introduce program participants, if you
could get the next slide, please?
[Slide.]
MR. HARRISON: This is just some general
information on the two demonstrations. Key information here
is, as was mentioned earlier, the vessel types, nozzle
supported, CE fabricated, B&W; fabricated, NSSS designs,
Westinghouse 4-loop, B&W; 2-loop.
With that, I would like to introduce our first --
the Marble Hill.
MR. ART: My name is Ray Art and I am with the
ASME Research Center here in Washington.
Could we have the first slide, please?
[Slide.]
MR. ART: This is an overview of our presentation.
I'm going to talk about the first three or four slides and
then David Howell from the Westinghouse Corporation will be
discussing the details.
As you can see, the general objectives of the
Marble Hill project, the Marble Hill ADP team members and
the indirect gas heating system. Then I will turn it over
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to David and he will take care of the rest of them.
We have a special treat for you this afternoon.
We have a video tape which we will show at the end.
CHAIRMAN JACKSON: Thank you.
Could I get you to speak a little closer to the
microphone? Thank you.
MR. ART: The general objectives of the Marble
Hill project, the joint industry/government effort to
demonstrate the engineering feasibility of a reactor vessel
annealing system, and I do mean joint. We've got -- you
will see the team members. We also had the Japanese and
French involved in this program.
The Marble Hill project demonstrates indirect,
gas-fired annealing technology, as was indicated earlier.
This was the first success in-place anneal of a U.S.
commercial reactor vessel in a typical U.S. nuclear power
plant.
The Marble Hill ADP members are shown here and
under the leadership of the Department of Energy and Sandia
National Labs, the American Society of Chemical Engineers
served as the primary contractor for the project with the
Westinghouse Cooperheat Team doing the technical design and
the operation itself.
Electric Power Institute, Research Institute, did
include a number of their members as contributing funds to
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the project, including the EDF or the French utilities.
The Westinghouse Owners Group was another large
group that contributed. Consumers Power who, as you know,
runs the Palisades plant, Duquesne Light, which runs the
Beaver Valley station.
The Central Research Institute, Electric Power
Industry is the Japanese component and they visited the site
and participated in the steering committee meetings.
Meanwhile, we had invited and received close
observation by the NRC staff throughout our presentation.
Could I have the next viewgraph, please?
I am going to turn it over to David Howell, who
will give you the details now of how we did this operation.
MR. HOWELL: Good afternoon.
[Slide.]
MR. HOWELL: What we have on this slide in front
of you is a schematic of the heating technology that was
used as the Marble Hill demonstration. As Mr. Franks had
mentioned, the demonstration had two significantly
technologies that were used. I will try to go through in
brief detail the differences or the uniqueness of the
indirect gas approach.
If we could have the slide -- yeah, the slide
that's back up on the screen.
What you see in the slide is a schematic showing a
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heat source which is propane gas burners on the outside of
containment that is heating air that is blown through a
ductwork system that goes into containment and then down
into a large stainless steel heat exchanger that is actually
in the vessel itself. There is no interaction between the
hot air in the vessel and the actual wall of the vessel
itself. It is totally contained inside a five-zone heat
exchanger and then recirculated and then piped back out of
containment through the exhaust ductwork.
There are several unique things about that design
that made us want to pursue that. One is that it is much
lighter weight from the standpoint of what has to be handled
in containment itself, it is very easily decontaminatable
because the outside surface is basically stainless steel and
it does not have any components inside the vessel that
really are prone to failure. It is really an air-moving
machine. And it also very definitely separated the
contaminated air from any of the hot air that was going
through. So that was one of the thrusts of the design.
If I could have one of the next slide? Or,
actually, before we show the next slide, I would like to run
the video and we will give you a little picture of what
happened at Marble Hill and then we can walk through some of
the details that took place at the site if we can run the
video now.
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What you see, of course, is the sign for the
utility. This is a cancelled plant that was cancelled in
the early '80s. The Marble Hill had two units. The first
unit, which is what we did the demonstration in, was 65
percent complete. All of the piping was intact.
What you see right now is a picture of the vessel
with all the instrumentation, internal instrumentation was
welded to the vessel.
What you are looking at right there is a thermal
plug that blocked the air from transitioning down the
nozzles. There was instrumentation as well on those thermal
plugs such that we could tell what the stresses in the
piping were. You can see several runs of instrumentation
that were welded to the vessel and the lines coming out.
There is a detail right there of one of the instrument lines
that has been attached to the inside of the vessel and the
routing of that cable as it goes up and out of the vessel.
It is very important to the demonstration for that
to be done in a quality manner such that it did not
interfere with the installation of the heat exchanger in any
way.
You can get a picture of some of the runs in the
vessel and as they were installed in the beginning, they
were tagged, marked, checked out thoroughly, calibrated
before any of the actual heat exchanger was installed.
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What you are looking at right now is the loop
piping coming out of the vessel with the main isolation
valve. Several instruments were installed on the vessel.
When we go around the piping, we will be going through that
a little bit later as to the detail.
What you have in that video right there is the
heat exchanger itself with the air ducts going in and out,
technicians are going ahead and installing the final
instrumentation. The lift rig being lowered down onto the
heat exchanger on the reactor vessel top cover. You can see
insulation that is on the top cover to prevent the heat from
escaping and keeping the control of the actual heating
process itself.
On the outside of containment are the gas tanks
and you are looking at one right now that control the flow
of gas to the burners, as we will talk about later it is
really fully combusted, the gas, before it enters into the
heat exchanger thus no combustion actually takes place
anywhere inside of the piping or the ductwork.
The hot air, the air is piped from fans into the
burner receptacle. This is a burner right there that you're
looking at, the silver, and this is the flame that comes out
of the burner and then heats the air that is taken down into
the heat exchanger itself. It is a very controlled process
that is utilized.
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The heat exchanger itself is now being positioned
over the vessel and lowered in over a series of guide studs,
guide pins very similar to what you would see for a normal
internals installation. As you can see as it goes down into
the vessel, guided down over those long guide studs that you
see sticking up right there it looks very much like,
actually, a lower internal is being installed into the
vessel.
As you can see, it's passing over the guide studs
as it is going down into the vessel. You have a series of
guide studs both fine and gross control such that it picks
up on the studs, avoiding any damage to the vessel as it is
going down.
Now, one of the things we obviously had the luxury
of at Marble Hill that we will not have as much of at a
commercial plant is being right down on the vessel flange
and much more of a hands-on approach to guiding that in.
But the basic process will be very similar.
What you see right now is the actual setup with
all ten lines, both five inlet and five exhaust coming out
of the burners and entering into containment. The bottom
set of ductwork going in is the hot inlet air and the top
set of ducts coming back out are the exhaust air. Fully
insulated and safe to the touch from the standpoint of any
hot pieces of material.
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Then going down into what we call a bedspring
structure that goes down into the vessel, into the heat
exchanger that is sitting in the vessel.
Instrumentation runs coming out on the top of the
deck. This is just a strip chart recorder for gross
temperature inside the data acquisition trailer, which is
where you are looking at right now, all of the
instrumentation both external and internal being monitored
and being used to both control the anneal as well as monitor
the movements of the vessel and the stresses and strain
results.
Once the annealing was completed, the disassembly
took place, basically in reverse. You can see the ductwork
that was taken out. There is some discoloration but there
was no deformation whatsoever in the ductwork that was
detrimental.
They are now just disassembling the
instrumentation runs so they can go ahead and pull the heat
exchanger out, lowering the lifting rig down and taking the
heat exchanger out of the vessel.
We were very fortunate at Marble Hill that many of
the existing cranes and things that were intended to be
installed were functional and running and it took some work
to keep up with the maintenance on them but it worked out
pretty well for us.
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As you can see, the heat exchanger pulled out.
Once again, it is a stainless steel skin and there is some
discoloration due to the heat but not unexpected. On the
sides of the heat exchanger, several retractable
thermocouples that measure temperature as well on the vessel
which would be used in a real anneal because, obviously,
there is not an opportunity to jump down in the vessel and
weld thermocouples on the ID of the vessel.
Good picture of one of our technicians.
[Laughter.]
MR. HOWELL: Once again, the disassembly of the
vessel. We learned a lot of things which we will talk about
a little later from the anneal and how to process the
equipment in and out of the containment that will be very
helpful for an actual anneal.
And I believe that is the end of the video.
Okay, if we move to the next slide, please.
[Slide.]
MR. HOWELL: Going through what the purpose of
some of the demonstration would be, along with the actual
implementation, several items had to be completed to
validate a model. We had thermal and stress analyses were
completed and the purpose of that is to validate the model
of the vessel for future efforts as well as to make sure
that the actual results we got matched the calculated
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results.
It also provided a basis for instrumentation
selection, the type of instruments we were to use as well as
the location of those instruments based on the stress and
thermal analysis. Of course, it input for these
measurements we wanted to take and NDE inspections that we
wanted to take for the critical portion of the vessel. They
were both done in 3D, both the analytical and thermal
models.
Next slide, please.
[Slide.]
MR. HOWELL: Several of these sensors, and I
detailed them on this slide, there were actually 228
thermocouples and RTDs that were put, as you saw in the
video, both on the reactor vessel internal and external
surfaces, the RV nozzles, the flange, any of the supports.
The cavity concrete, as was mentioned before, was very
important to us to ascertain a temperature and, of course,
the piping.
We also checked not only temperatures but
displacements. We wanted to characterize the movements of
the various components in the vessel. The support pads, the
bottom of the vessel as well as the piping. We had 14
string gauges as well on the reactor coolant piping and the
nozzle and pipe welds.
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We wanted to be very clear that when we left this
vessel it was in a shape that could be used again, so we did
pre and post dimensional checks and we did those based on
the results of the thermal stress analyses at key interface
locations for both the vessel internals and the head setting
operations which are the key measurements for continued
operation to make sure the actual components will go back
into the vessel.
We also did some noninstructive examinations
including dye penetrant, visual and ultrasonics on the
selected loop and piping welds that were of interest based
on the critical stresses.
Next slide, please.
[Slide.]
MR. HOWELL: As we commenced the actual site
effort once we had all of the results of the thermal stress
analysis and we had the maps where we were to put the
instruments and the procedures completed on how to do the
measurements, we arrived on site on May 6 to do a cleanup of
the Marble Hill site.
As you can imagine, a site that has been cancelled
for about ten years was not in the best of shape and we had
several days and weeks of cleanup to make it safe, which was
one of our top priorities on this project.
We actually commenced the heating, the annealing,
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of the vessel heatup on June 24 after about a month, a
month-and-a-half of preparation. We commenced soak on June
28 at four o'clock and we completed the entire effort which
includes the cooldown to less than 200 degrees on the 8th of
July.
The team, basically, after the cleanup, imposed
measurements, post NDE, left the site on July 24 and are now
working very diligently to come up with several reports, the
draft field service report which basically has all of the
data that was collected on the site as well as the
procedures. It is being issued today to ASME and then will
be issued from ASME to the rest of the team.
The final report, the draft that Westinghouse will
be putting out to ASME will be complete in November and then
we expect the issuance of that report to the public in early
1997.
May I have the next slide, please?
[Slide.]
MR. HOWELL: What you have in front of you here is
basically a profile of the time-temperature curve that was
used. The dotted line is the average heatup rate,
approximate heatup rate which was 16 degrees Fahrenheit per
hour and you can see the actual very close to that. It came
up to approximately 850 degrees with a minimum soak of 825
all the way across for the seven-plus days and then dropped
28
down at a cooldown rate of approximately 14 degrees per hour
at the end.
Next slide, please.
[Slide.]
MR. HOWELL: So what were the results? We believe
that very successful results in that we demonstrated that
the full scale reactor vessel process at the nominal
temperature of 850 degrees was doable, we did that for seven
days. We did establish that the critical dimensions were
maintained pre and post and within the acceptable tolerance
of the manufacturing specifications. We were able to
control the heatup, soak and cooldown with the indirect gas-
fired process very well.
There are several advantages in that we were able
to actually input heat with one zone and draw heat out with
another zone at the same time to maintain those curves at
the minimum possible time that was allowable within the
curves.
The reactor vessel ID and OD instrumentation
functioned very well. They were all verified after the
demonstration that they did function, they were operational,
calibrated out very well. And the ending inspection of the
vessel proved that there were no indications that were
present that were not present before, so that's also a very
positive sign.
29
As I said before, one of our top priorities on
this program was the safety of our people and we had
absolutely no lost time accidents at the Marble Hill site.
Next slide, please.
[Slide.]
MR. HOWELL: The final assessment, once again, we
believe this to be in excess of a commercial-style reactor
vessel and it is indeed feasible. There were no reactor
vessel deformations that were deemed significant. We were
very pleased that the analytical model predicted both
temperature strains and displacements very accurately. We
had absolutely no damage that was noticeable to any of the
plant, balance of plant, piping loops, concrete supports or
anything else. And then we -- the vessel -- we believe that
the vessel annealing hardware and operation costs are
reasonable and we gained some insights on how to make them
better.
We also believe that this particular heating
system is very viable, as is electric, but both very viable
way to do this project and this process, very reliable. As
I said before, lighter weight and all of the components
accessible during the operation if there were to be any
problems. And we were very pleased, as I said before, about
the ability to control the -- control the multi-zone heatup
and cooldown with a forced cooldown capability.
30
We were able to quickly remove and install the
equipment and believe that that is also a very big benefit
for us in decontamination of the equipment and for ALARA
reasons.
That is really the end of my prepared
presentation, if you have any questions.
CHAIRMAN JACKSON: Any questions?
COMMISSIONER DICUS: Let me ask you one thing. I
understand that there were no particular significant
problems encountered in this process but did you have a list
of potential problems and the problems you found, were they
on your list or were there unexpected problems?
MR. HOWELL: Well, actually, we had a very
detailed readiness review process that the Department of
Energy and the team, the Westinghouse team went through and
had predicted several instances that we should be ready to
take on. One, for instance, was the loss of on-site power
and the loss of gas during the actual annealing and soak
period.
Both of those did occur and we were very well
prepared for them. And, as you can see in that curve, did
not even push us close to being out of the soak range, so we
did go through that process and felt that we successfully
handled it.
CHAIRMAN JACKSON: Okay, thank you.
31
DR. CHAPIN: My name is Doug Chapin and I am a
principal officer of MPR Associates, which is an engineering
company here in the Washington area, and I want to tell you
about the other half of the project, the Midland ADP, and in
the interest of time, my presentation is arranged so that
there are four or five pictures in the front and then some
text at the back and what I will do is get the pictures put
up and then I will sort of talk from the text.
So if I could have the first picture, please,
figure one.
Commissioner Rogers is probably familiar with this
picture. He has been briefed on the Russian annealing a
couple of times. This is a picture of the actual furnace
being lowered into the vessel at Novovoronezh reactor in
1991. This was an annealing that the NRC witnessed and was
very interested in and we had three people who went and
participated in that process and were on site.
What you see in this picture is the furnace itself
with three rows of heaters and then the layers of insulation
over the top and when I get to the picture of the American
furnace, you will see that one of the major differences is
that our furnace needs to be much taller because we need to
anneal a much taller zone on the vessel.
Could I have the second figure, please?
This shows an elevation view of a B&W; two-loop
32
plant and it is a different configuration than the
Westinghouse plant and there are a couple of features that
are important as far as the annealing is concerned.
At the bottom, this vessel is supported by a skirt
so that when we heat the vessel, this vessel will grow up
from the support at the bottom. The large hot legs and the
cold legs from the steam generators are long runs of piping
and we have to account for the loads and the thermal growth
that are associated with the piping in the --
CHAIRMAN JACKSON: Excuse me, could you put the
picture back on, please?
DR. CHAPIN: Oh, I'm sorry, yeah.
Go back to figure two. There we go.
The support skirt is at the bottom and then the
two large steam generators to the far right and left and the
hot legs often called "candy canes" from the shape that you
can see, they go out of the vessel and then they run up
vertically and come back in.
The cold legs come from the bottom of the steam
generator into the pumps and then back into the vessel. So
this is a little different configuration and this is one of
the things that is different and we are going to get sorted
out in this annealing is the difference between the nozzle
arrangements and the support configurations between the two
plants.
33
The team that's associated with doing this Midland
is MPR is the prime and there is a Russian consortium called
MOHT, which is the same company that has done the annealing
or group of companies that has done the annealing in Russia,
and Framatome Technologies who used to be B&W; Technologies,
as the other major player.
The key supporters are, of course, DOE and our
primary contact is with Sandia and then the various
utilities who support the group are the Empire State
Electric Research Company, ESERCo, the Electric Power
Research Institute, Consumers Power, General Public
Utilities, the Tennessee Valley Authority and then there are
two international participants, CRIEP, the Central Research
Institute of Electric Power in Japan, and we also have a
commitment from EDF and I guess you would characterize that
as the check is in the mail, but we have international
participation as well.
Can I have figure three, please?
Let's leave it up and I will talk about it a
little bit.
This shows the furnace in the vessel at Midland
and, as you can see, the furnace here is much taller. There
are probably about nine rows of electric heaters as opposed
to three in the Russian furnace. And if you look at the
plan view at the top that shows where the nozzles are, you
34
can see that the nozzles are rather asymmetric around the
top of the vessel. The hot leg nozzles are larger and are
centered between the two cold leg nozzles and then the
injection nozzles for core flooding are between those.
One of the advantages of the electric furnace
technique is that it provides a high degree of control of
the heat input to the furnace and so one of the things that
we will be able to check out in this particular annealing
demonstration is our ability to control the temperatures not
only axially but azimuthally, if you will, around the vessel
and account for the various heat losses. We will measure
the axial and circumferential temperatures and we will
control the furnace with an automatic feedback loop using a
computer control system.
We will have about 72 thermocouples which are
associated with the furnace itself which are retractable and
when the furnace is installed, they are tucked into the
furnace and then once the furnace is installed they go out
and touch the inner wall.
In addition, we will have about 140 or so
additional instruments, thermocouples, strain gauges,
displacement gauges which will be put around on the piping
and the supports so that we can monitor the parameters.
Could I have figure four, please?
This shows a plan view of the plant and what I
35
want to use this for primarily is to illustrate where we put
the finite element model.
As my colleagues from Westinghouse and ASME
pointed out, one of the key results of this demonstration
project is the ability to have a good model of what's taking
place so that we can migrate this technology, this analysis
capability to other situations so we have made a detailed
finite element model.
If I could have figure five please?
This shows the finite element model and the colors
represent temperatures. The high temperature is the red
zone and that's -- these are preliminary numbers and not
precise but, to give you a feel, the red is say roughly 850
degrees Fahrenheit and the blue at the coldest ends is about
100 degrees Fahrenheit and so this is the temperature
distribution in the vessel and we use a code to determine
what the stresses are that result.
We are using a commercially available program
which is called ANSYS, which is a standard code and so this
is something which will be readily usable.
Then, if I could go to the last slide in the
package, number 10, please?
[Slide.]
DR. CHAPIN: This gives a sort of status and the
future milestones. We started the work in May of 1995. We
36
have had a lot of interactions with the Russians. The next
trip to Russia will probably be in about a week and a couple
of our engineers will go over to go over some key test
results and some fabrication results that will be available
in Russia at that time.
The site work has begun and we expect to have the
furnace on site in November of this year and we will do the
annealing in December and we expect to have the reports all
issued by September of next year.
That's all I have at the moment.
CHAIRMAN JACKSON: Commissioner Rogers?
COMMISSIONER ROGERS: No questions.
CHAIRMAN JACKSON: Thank you.
MR. FRANKS: I think that concludes our technical
presentations so we will turn it back over to the staff.
CHAIRMAN JACKSON: Mr. Howell, Dr. Chapin, I hope
you are going to still be here, I have a couple of
questions.
DR. CHAPIN: Yes, ma'am.
MR. HOWELL: Yes, ma'am.
CHAIRMAN JACKSON: Thank you.
This is group three.
MR. MAYFIELD: As you heard from the Westinghouse
folks, they completed the annealing and have gotten off
site. We had a team of a number of folks that we will talk
37
about in just a minute that were on site. We had a number
of observations that we made that we are going to ask Debbie
Jackson to address. But before turning the presentation
over to her, I wanted to make at least three key points with
you.
First of all, from what we have seen so far, we
have not seen the detailed data, but from the site
observations and what information we have so far, it does
appear that the first annealing demonstration was
successful. They got the vessel within the anticipated
temperature range, followed the anticipated temperature
profile pretty well and didn't seem to distort the vessel.
So that was certainly key observations for us.
There were no particular -- well, no significant
problems identified from the staff's observations so, while
we were on site, we were looking very carefully for what was
going right, what was going wrong. You will hear a little
bit about some fire protection issues that were identified.
We have passed those on to the NRR staff and back to
Consumers Power for their consideration as they are planning
the Palisades demonstration.
So based on the information that the staff has
available to it so far and our site observations, we feel
like this first demonstration was successful.
If I can have the next slide, please?
38
[Slide.]
MR. MAYFIELD: I noted that there were a number of
people on site. We had at varying times 16 people from the
staff and our contractor, Oak Ridge National Laboratory, on
site. This was a program that was managed by the office of
research, however, we had interaction from the NRR folks,
from the EDO staff and from two of the regions. This is, we
believe, an example of what we can do when we work from an
interdisciplinary approach as well as interoffice approaches
to these things.
So we feel like the staff had an opportunity to
get a good look at the demonstration and we think we had the
right people on staff at the right time or on site at the
right times to take a look at what was going on in the
demonstration.
Now, Debbie Jackson was our task manager for the
on-site activities and we have asked her to provide you a
summary of the staff's observations.
MS. JACKSON: Thank you. Good afternoon.
As Mike stated, the preliminary conclusion from
the staff was that the anneal was very successful and these
conclusions are based on the information that we have
received from the pre and post NDE inspections and the pre
and post dimensional analysis.
The NRC staff was on site to observe the setup of
39
the heater, installation and removal of the heater, the
ductwork and the instrumentation, assembly and installation
of the reactor vessel top cover, pre and post NDE
inspections and dimensional checks, setup of the burners and
the heatup, soak and cooldown.
One point that we wanted to stress was that the
Westinghouse and Sandia personnel were helpful and they were
accessable to the NRC and Oak Ridge staff while we were on
site. They assisted in answering questions and escorting us
while we were on site and at one point the flexibility of
the NRC staff was increased by allowing two NRC personnel to
be trained to escort other NRC and Oak Ridge visitors on
site.
All of the instruments operated as specified. The
NRC staff, while on site, obeyed the rules in the
Westinghouse site procedure and the site safety was greatly
enhanced by a cleanup operation which was mentioned
previously and the appointment of a full-time safety
engineer whose planning and effective execution of safety
procedures was very obvious while we were on site.
May I have slide number 11, please?
[Slide.]
MS. JACKSON: One thing I would like to emphasize,
even though these findings were not a major problem at
Marble Hill, they would present a problem if these were
40
identified at an operating plant. Some of the activities
took a little longer than anticipated. The fabrication of
the ductwork required on-site engineering. The fabrication
of the ductwork was prolonged by some additional welding
that had to be done on site.
And a dimensional problem was encountered with the
installation of the thermal plug that you saw in the video.
It had to be removed, machined and reinstalled while we were
on site.
The issues dealing with fire protection, there was
a problem with the proximity of potential ignition sources
which -- specifically electrical equipment, to the propane
tanks which were located on the site. And the propane tanks
at an operating plant would have to have been rotated 90
degrees from the position they were at Marble Hill. If the
tanks were inadvertently ignited, they would move toward
safety-related structures, which would not be acceptable.
Another issue was the manual fire suppression
capability was only provided by fire extinguishers and a
single hose with a fire hydrant and all of these issues were
discussed with Palisades personnel from our fire protection
engineer.
May I have slide number 12, please?
[Slide.]
MS. JACKSON: An observation procedure was
41
developed for use by the NRC and Oak Ridge personnel in
preparing for site visits, site observations and preparing
trip reports. And the procedure was consistent with the
DOE/NRC MOU and it emphasized that the NRC's role while on
site was to be an observer. No inspections were to be
performed while we were on site.
May I have slide number 13, please?
[Slide.]
MS. JACKSON: Both organizations involved, the NRC
and the DOE team, will be obtaining reduced data which was
recorded from the Westinghouse, Cooperheat and NRC
instruments and these instruments included temperature
detectors, strain gauges and displacement gauges.
The real data that's being reduced includes
measurements that were taken at different time intervals at
every one to two minutes. No conversions were required on
these measurements. They were all recorded in their proper
form.
We wanted to note some of the occurrences that
happened during the anneal. I had previously mentioned the
setup of ductwork that required additional welding while on
site. The plant personnel responded by adding an additional
shift of welders while we were there.
There was a minor problem with a loose connection
from the diesel generator from the saddle tank on the
42
outside to a compartment that resulted in a leak of fuel
inside the compartment.
There were problems with the polar crane at
various times during the anneal. It was inoperable due to
blown fuses, failed circuit cards, motor repairs and
overhauling which was required but, as was previously
mentioned, the anneal still went on with that.
A report documenting the staff's assessment will
be provided in the near future and will be available for
review.
This concludes my portion of the presentation.
CHAIRMAN JACKSON: Let me ask you a question and
to some extent I am also asking it of Mr. Howell and
Dr. Chapin.
Are there any other issues other than what you
have outlined that remain in transferring the gas and
electric technology from the demonstrations, well, you've
seen the one, to irradiated vessels?
MS. JACKSON: There probably would be problems --
well, in terms of the ductwork, the ductwork, the fit-up of
the ductwork, that was something that would result in
increased personnel exposure because it would just take a
longer time to weld the pieces of ductwork together instead
of having the ductwork come on site fabricated. It arrived
at Marble Hill in 10-foot sections and collars had to be
43
welded to connect the 10-foot sections together so if the
sections could arrive on site in longer pieces, then that
would require less work while on site.
That would be my only observation. If someone
else has something --
CHAIRMAN JACKSON: Are there any issues with
respect to ease of installation of equipment with the
bioshield heating, with insulation interference, anything
like that?
MS. JACKSON: I think --
CHAIRMAN JACKSON: And maybe some of the --
MS. JACKSON: I think someone from Westinghouse
would be more --
CHAIRMAN JACKSON: In terms of your experience,
because you have actually been involved, it is a different
technology but you have actually done irradiated vessels,
you've done the demonstration with the gas-fired and so I
guess what would you say are any critical issues that relate
to going from the actual -- apparently successful
demonstration in an unirradiated environment to --
MR. HOWELL: Well, as Debbie mentioned, there are
things that we will definitely do differently at Palisades
on the ductwork part of the detailed design of the Palisades
program, to provide quicker connection ductwork and more
basically planning on the lengths of pipe and things of that
44
nature that would be put into place. So that is a key
difference that we would have to deal with because of the
dose levels.
Obviously, this particular demonstration, as I
expect is the case with Midland, does not mock up the actual
shielding that is required for the lower internals and upper
internal structures that has to be put in in an actual
annealing. That design is being completed now for the
actual shielding of those components and the routing, in our
case, of the ductwork around that shielding.
So those are two, you know, specific differences
that we have to address and we are addressing at this time.
CHAIRMAN JACKSON: What would be the effect on the
reactor vessel which was being annealed if the heat source
really was lost? You mentioned you were able to maintain
the soak but what would happen if you actually lost your
heat source and what would be the effects on the reactor
vessel?
MR. HOWELL: The heat source itself is such that
we have a lot of backup so that is a very low probability
but the intent really is to maintain a vessel at 850 degrees
for a certain period of time. If the heat source were to be
lost for some period of time, it could be regained and relit
and gone back to get the appropriate time added into that.
We believe that would be also successful. So as long as the
45
total time at annealing temperature is maintained.
CHAIRMAN JACKSON: Is that true? You're saying,
if it were annealed, if it were meant to be annealed for a
week and it was annealed for two days and you lost your heat
source and so it totally cooled down, then you annealed it
for five more days, that's the same as annealing it for
seven?
MR. HOWELL: There is a timing factor that would
have to be taken into consideration but basically the total
time at temperature is what gives you the metallurgical
recovery.
MR. STROSNIDER: Jack Strosnider with the staff.
I just mention that in the event that for some
reason the time temperature envelope is not followed during
the anneal, the rule that was promulgated actually addresses
that situation and there are certain requirements with
regard to reassessment and whether the licensee could take
credit for that or not. So that's been anticipated
although, as was pointed out, the intent obviously is to
have enough redundancy not to have that occur.
CHAIRMAN JACKSON: I note that there is a concern
with something called temper embrittlement that has to do
with segregation of impurities. Can you -- can anyone here
give us some background on that and its potential impact on
annealing projects in the U.S.?
46
MR. MAYFIELD: Well, this is something that we
have been looking at as part of our materials research
program for some time. There are some results. Well, it is
a problem with some of the Russian reactors, the phosphorus
content tends to run higher. So it is a much more
significant problem for them than it has been for us.
Nevertheless, even for our materials, there is
some potential for temper embrittlement. It is something
that we have been looking at, we have programs underway to
address it. Based on the information that we have
available, the research results we have available, we do not
believe that it is a significant problem for the U.S.
materials. We believe that, to the extent it is an issue,
it has been incorporated in the recovery database so it is
modeled as part of the recovery equation.
It is implicitly in there. However, that is not a
very satisfactory answer. It probably doesn't suit you; it
certainly didn't us. So we have asked Oak Ridge to pursue
this in a more aggressive manner.
There are data available from the British that
suggest that for our classes of materials this could be an
issue. However, when we looked at those data, it appears
that they went to some lengths to create a situation where
the materials would respond to a temper embrittlement
phenomenon.
47
Based on the information we have, again, we do not
believe it to be a significant issue today, however, it is
something we are continuing to pursue in the research
parameter.
CHAIRMAN JACKSON: Can you tell me how well the
results of the annealing can be determined by existing
nondestructive measures? I mean, how do you know that, in
fact, the annealing was successful and you've actually been
involved with --
DR. CHAPIN: What is normally done is you actually
take samples and you do an annealing recipe and you
demonstrate that for the steels that are involved, that the
annealing recipe has in fact restored the properties. The
Russians have, in fact, taken samples from the inside of the
vessels after they have been annealed using electro
discharge machining techniques very like we used to cut
pieces out of the inside of the TMI II vessel and have
essentially established on a scientific basis, if you will,
at the Karchatov Institute that for this set of materials,
this irradiation history, this annealing, this
reirradiation, the desired property change is obtained.
MR. STROSNIDER: I just wanted to add two
comments. One with regard to the temper embrittlement
issue, we have asked the licensee also to address that issue
for Palisades specifically and their plan involves some
48
testing to look for inner granular failure and some evidence
to see if that's something that might occur, in which case
they might have to take some additional actions. So we have
sent them in one of our requests for additional information
for them to identify how they are going to address that.
I guess the other comment is with regard to the
recovery of the material toughness, if you look at the rule,
I think, the reg guide, there are actually three ways that
this can be done. One is using surveillance specimens which
can be put through the same heat treatment. Another would
be to remove specimens from the vessel. Finally, there is
the analytic methods that have been developed based on the
database.
Those are not nondestructive testing methods, as
you asked, and we recognize that, but I think when we use
these alternative methods what we have done is applied
appropriate margins so that we feel that we have covered the
uncertainties. Now, there is probably a penalty that is
paid there in applying those margins but that's the best
approach we have at this time.
CHAIRMAN JACKSON: So you feel there is additional
conservativism built in because of this lack of direct
ability to do that?
MR. STROSNIDER: Right.
DR. CHAPIN: Madam Chairman, could I address a
49
couple of other practical factors, I guess, that came out of
the Russian --
CHAIRMAN JACKSON: Yes, please.
DR. CHAPIN: One of the things you mentioned was
radiation levels and one of the things that is striking is
the radiation levels in the Russian plants are very
different than those in the U.S. plants. So even though we
have irradiated vessel experience in real plants in Russia,
the radiation levels at an American plant will likely be
higher and so we will have to deal with the shielding and
with access to the vessel flanges, all of the real things
that need to be done.
CHAIRMAN JACKSON: Let me just stop you there for
a second. Is that the reason the expected dose rates at
Palisades are a factor of 10 higher than those at the --
that were estimated for the Loviisa Unit I in Finland? I
mean, what is it that gives you that difference?
MR. RUSSELL: The dose rates are almost an order
of magnitude difference between what was seen in the Russian
reactors and what is seen in U.S. reactors.
CHAIRMAN JACKSON: Right.
MR. RUSSELL: I am not able to address
specifically the issues of the dose estimates now. That is
still under review by the staff and whether it is ALARA or
not and some of the steps they are going to take to reduce
50
the budget for dose that they are expecting for the job.
COMMISSIONER DIAZ: But if I might say, this is
something that is directly related to those reactors. The
power level is 440 megawatts and the construction of the
vessel is different so that is a significant difference.
DR. CHAPIN: And the vessels are clad, usually, in
the United States and so there is more nickel content and so
typically the dose level is higher.
CHAIRMAN JACKSON: Okay.
DR. CHAPIN: Two other items.
One is water. The presence of water in the vessel
or the likelihood of water being introduced into the vessel
while it's hot is a bad thing and so the Russians have spent
a lot of effort in their own plants making sure the vessel
is carefully isolated from sources of water.
This sounds straightforward but, if you look in
our plants, you have a refueling pool, you have to have a
place to put the reactor internals and so there are some
engineering issues associated in a real plant with how you
make sure things really are dry and that water is not
present.
The last one is the variability of the insulation.
In a real plant, and I think this is one of the things that
we learned, we will learn out of these two plants, the
vessel insulation will not be perfect and so you can't do
51
the stress analysis on the basis of a neat boundary
condition assessment of it being perfectly insulated. There
may be patches, there may be pieces missing or cracks. And
so those have to be accounted for in the real -- in the real
world.
CHAIRMAN JACKSON: That's good. That's what I was
interested in. Thank you.
MR. TAYLOR: Okay, Jack?
MR. STROSNIDER: If you could have slide 14?
[Slide.]
MR. STROSNIDER: I would like to provide a little
bit more background on the regulatory framework involved
with reactor pressure vessel assessments. Mike Mayfield
talked briefly about it. I will talk a little bit more
about that.
Then I want to talk about Palisades reactor
pressure vessel and the licensee's annealing plans of that
vessel and also I want to mention then some revised fluence
calculations that are under review for the Palisades vessel.
There is a number of regulations that apply to
reactor pressure vessels. I am hitting some of the high
points here. In particular, 10 CFR 5061 normally referred
to as the Pressurized Thermal Shock Rule. Vessel
embrittlement is a function of fluence and chemistry,
particularly copper and nickel and 5061, the ETS rule,
52
specifies how to evaluate embrittlement of reactor pressure
vessels as a function of fluence in the chemistry.
It also establishes screening criteria to limit
the amount of embrittlement to assure that there is adequate
margins in the vessel for anticipated transients and
pressurized thermal shock type events.
The level of embrittlement is calculated in
advance such that there should be time to take appropriate
actions if a reactor vessel is predicted to reach the
screening criteria. Those actions can consist of either a
plant-specific evaluation. The screening criteria were
developed based on generic assessments. There is the option
for a licensee to look at their plant-specific systems,
thermal hydraulics, reactor vessel design, et cetera, to
evaluate it that way. Or the other option is annealing.
With regard to annealing, as was mentioned
earlier, we have promulgated 10 CFR 5066, the annealing
rule, and also Regulatory Guide 1.162, which provides
guidance on how to implement that rule.
Just to hit a few high points in that rule and
regulatory guide, there is a requirement that a licensee
which desires to anneal the reactor vessel submit a thermal
annealing report three years before actually performing the
annealing. This thermal annealing report has four major
sections in it. One is an operating plan. The operating
53
plan consists basically of describing how the anneal is
intended to be performed; that is, what sort of heating
system, what sort of temperature time history, that sort of
thing.
Also, it includes an assessment of what sort of
thermal gradients, thermal stresses and strains would exist
in the vessel and it addresses radiation dose ALARA
considerations.
The second part of the report is the inspection
and test plan and this is basically the precert by the pre-
anneal and the post-anneal in-service inspection or testing
that would be done to demonstrate that the vessel wasn't
damaged, wasn't deformed, you know, in a damaging way.
Then there is a section with regard to fracture
toughness. That is, predicting the level of recovery from
the anneal and also a followup on, after the vessel is put
back in service, what the re-embrittlement would be. That
has to be defined how that is all going to be done. Then,
finally, a section which deals with identification of
changes, necessary changes in the technical specifications
or unreviewed safety questions.
So that has to be submitted three years prior to
performing the anneal. The NRC staff will evaluate that
thermal annealing report and put their evaluation in the
public document room. It is really an opportunity for us to
54
look at their plan and raise any red flags and, as I said,
particularly with regard to the unreviewed safety questions,
it's the licensee's responsibility to identify those, that
we look at the plan with particular focus on that.
A couple other important things is that both
before the annealing is performed and after the annealing is
completed, the NRC would document their review in the public
document room and there is also a public meeting that would
be held before and after the annealing to basically inform
the public what was done and the NRC's evaluation and
inspection results.
So that is sort of a summary of the regulatory
framework that applies to annealing. With regard to
Palisades, we completed an evaluation in April of 1995 in
which we concluded that they would reach the screening
criteria. At least they were okay until 1999. That
evaluation was consistent with the 5061, the Pressurized
Thermal Shock Rule. The current license for Palisades
expires in 2007 so they would fall somewhat short of the
current operating license with regard to the life of the
vessel.
So, if I could have slide 15?
[Slide.]
MR. STROSNIDER: Recognizing that, Consumers Power
Company, the licensee for Palisades, has developed a plan to
55
anneal the Palisades vessel. It would occur during the 1998
refueling outage. We are in the middle of the review of
this plan.
They put together a thermal annealing report
consistent with the regulatory guide and they have submitted
portions of that and specifically they have submitted the
operating plan which, as I mentioned, talks about heat
source, how it would be done, thermal and stress analysis,
those aspects of the annealing. They even submitted the
inspection and test plan and also the fracture toughness
evaluation that is recovery and re-embrittlement.
They have submitted those portions of the plan
with the exception of some work they are going to do to use
the results of the Marble Hill anneal to benchmark and to
demonstrate the adequacy of their plan in some of these
areas. And just to give some examples, and we just went
over some of this, but I think some of the important parts
of the annealing demonstrations.
First, to demonstrate that the calculational
methods, that is the computer codes that are being used for
the heat transfer and stress analysis, in fact, work and for
Marble Hill those analyses were done ahead of time and they
will be compared with the actual results from the
instrumentation.
The next thing is to demonstrate what
56
instrumentation is actually necessary and that it works well
in terms of monitoring the reactor vessel and other
components, including the piping and bioshield wall and
containment structures during the annealing for temperature
and deformations.
This is an important area if you couple the
analysis and the instrumentation aspects because
installation of instrumentation is very expensive, not only
in terms of money but in terms of exposure. So there is a
desire in a plant-specific basis to minimize the
instrumentation necessary and the idea of part of the
demonstration anneals is that you can identify critical
instrumentation and verify that you have an adequate amount
to control the annealing. Obviously, a demonstration of the
heating system and the ability to control temperatures.
One of the requests for additional information
that we sent out did ask the licensee to address the
differences between Marble Hill and Palisades and
specifically tell us what differences would be expected and
why.
So that is how some of this annealing
demonstration program is being applied on a plant-specific
evaluation.
If I could have slide 16?
[Slide.]
57
MR. STROSNIDER: The other thing that's going on
with regard to the Palisades vessel is that in April of '96
the licensee submitted a revised fluence analysis for the
Palisades vessel and this basically -- they proposed a
change in the fluence evaluation from that that was used in
our earlier evaluation.
What they have submitted indicates as much as a 25
percent reduction in fluence, as a result of revised
geometry and dimensions for the vessel, reassessment of the
fluence in earlier cycles, I think looking at the actual
power levels and what was happening there, and changes in
the computer code, the calculational methodology.
This submittal is under review. We are reviewing
it in parallel with the annealing report that was sent in.
We do plan to perform independent calculations to verify
their calculations.
It is important, obviously, to note a 25 percent
reduction in fluence could have some impact on their plans
for annealing. In fact, if we found that a 25 percent
reduction was, in fact, acceptable or appropriate, that
would extend the life of the vessel to around 2011, which
would be past the end of the current operating license. So
this is an important review going on in parallel.
CHAIRMAN JACKSON: Do you anticipate completing
that review in a time frame -- I note that you had indicated
58
that Palisades was planning to anneal their vessel during
the 1998 refueling outage and so the way things are
tracking --
MR. STROSNIDER: I understand, and this review is
being done by Reactor Systems Branch, but I understand that
that should be completed by the end of the year, assuming
that we get appropriate responses to the RAIs, requests for
additional information, that we sent out.
So I think, yes, it will be done well before the
anneal.
Also, with regard to the annealing plan itself,
those additional sections that remain to be submitted, we
are anticipating receiving those by the end of the year.
So, early next year, we should be getting pretty far along
in these reviews.
So I guess that is basically a summary of where we
are in licensing space. We've got two reviews that are
going on and it will be sometime early next year or so when
we can really give you the results of all of that.
MR. TAYLOR: That concludes the staff's
presentation.
CHAIRMAN JACKSON: Questions? Commissioner
Rogers?
COMMISSIONER ROGERS: Yes.
With respect to Palisades, my recollection seems
59
to be that they were trying to move on a much faster
schedule than what you have just described some time ago,
isn't that right? Didn't they have a plan to be much
further along on this than they are right now?
MR. STROSNIDER: I think that's correct. Some of
their earlier plans had a more aggressive schedule.
COMMISSIONER ROGERS: And there was a great
concern about our being able to, from our end, being able to
support that schedule that they were on. My recollection
was that they wanted to have something done by this fall but
I --
MR. RUSSELL: If we go back to the '94 time frame
when we discovered the information that was reported to us
about the differences in chemistry values and what that
meant, there were different approaches that were taken that
ultimately culminated in the staff issuing a safety
evaluation report, I believe, in the spring of '95 which
indicated they had until the 1999 time frame. That's when
the '98 type scheduling was established.
Prior to that, where we went in and did the more
sophisticated evaluation, in fact Mike Mayfield and the
staff were running the computers over weekends and quite
late at night to do some of the analysis, we thought it
could be that they had exceeded the screening criteria
either at that time or would shortly, which would mean that
60
the time frame for needing an anneal was sooner.
So we did an analysis using the same approach that
we used in developing the rule originally and the regulatory
guide, although we did do Monte Carlo analysis to more
systematically address some of the uncertainty.
As you recall, it was a rather skewed distribution
of chemistry values for copper and that made the analysis
somewhat difficult. It was some very high values and it
almost looked like it was random so there was no bell-shaped
curve. So that gave us some difficulty in handling the
review. We did it in a more rigorous method and we were
able to determine that there was time through the year 2000
or 1999 time frame, so that relieved some of that pressure.
Questions on whether there are going to be related
technical specification changes associated with this,
obviously there could be some with pressure temperature
curves following an anneal but the issues relating to an
anneal itself are the ones that we were focusing on today
and they seem to be reasonably on track.
The parallel review of the new methods that they
are using to calculate fluence, whether we are able to agree
with a 25 percent reduction or in some smaller number and
the time frame for that, we are going to try and complete
that by the end of the year.
COMMISSIONER ROGERS: One other question. Are
61
there any concerns about airborne contamination within
containment when you are annealing one of the irradiated
vessels?
MR. STROSNIDER: I think the answer is, yes, that
is an issue, obviously, that has to be addressed. I think,
as I understand it, one of the advantages of this gas-fired
hot air method was you basically contain that, you don't
stir up a lot of airborne activity. But it is a concern
that should be looked at.
I should mentioned that the Palisades review by
NRR staff is a multi-discipline review so it is not just
materials. We have health, physics people, fire protection
and other people involved so I can't personally give you a
lot more specifics on it except to say, yes, it is something
that needs to be considered and will be looked at.
CHAIRMAN JACKSON: Commissioner Dicus?
COMMISSIONER DICUS: No questions.
CHAIRMAN JACKSON: Commissioner Diaz?
COMMISSIONER DIAZ: Yes, just a comment.
I tried, and "tried" is the right word, to conduct
a materials program with Russia for the last three years and
one of the problems I was having is control. That is the
problem they have with their pressure vessels is they really
did not have quality control, quality assurance and so every
vessel is completely different and every amount of copper
62
and other extraneous materials is different.
I do believe that we do have a little better
handle on our vessels and therefore that would be a
favorable thing to note down the fact that we can predict
and we can do these things a little better.
The Russians do have a very serious problem. They
really don't know most of the time what do they have in
those vessels. I hope we do.
MR. RUSSELL: That was actually the subject of a
generic letter and we are developing a national database and
we have briefed the Commission on that in the past but we
are making progress on it and no longer treating the
information as proprietary so that it's available to all so
that information on sister vessels can be exchanged and
there is good progress being made both on the B&W; fabricated
vessels which we were quite a lot further along, plus also
the CE fabricated vessels.
I believe the database is available electronically
and the software that allows it to be manipulated is also
available so that utilities can see what information has
been submitted to the NRC and do their own searching. So
this is an area where we have made progress in the last
three years and we hopefully will not be surprised by
further findings of unusual copper results that cause us to
go into a faster mode of deciding what needs to be done on a
63
vessel.
MR. STROSNIDER: Just to expand on that a little
bit, if I might, as Bill mentioned, we put out a generic
letter. This was a supplement to Generic Letter 9201 and
what we found from our first round of reviews when we put
all these data into a database was that licensees weren't
necessarily treating the data consistently and, in some
cases, weren't aware of all of the data that were available.
So a supplement to the letter required the
industry to go out and search out all data and, in fact,
there is, as Bill indicated, a massive effort by the
industry right now going back to original fabrication
records and we expect that there will be a significant
amount of data added.
We are going to be receiving results and getting
heavily into the review of those next year and I think it is
going to about in December of '94 we completed a review of
all the reactor pressure vessels in the United States based
on the data we had available at that time. We will, next
year, have to go back and redo that based on the new data
that we receive.
At that point in time, I think we will have the
most comprehensive base line that we can have on reactor
vessels. So we still have some more work to go there but
the whole idea is to do that in a time frame to avoid any
64
surprises. We would like to get those data now and reassess
all the plants and if there are any plants whose status is
going to change from our previous evaluation we will
identify that as early as possible.
MR. RUSSELL: We did, however, apply the lessons
learned from Palisades in a conservative manner to make sure
that there was sufficient time for other vessels and that
Palisades, based upon everything we had, was the limiting
vessel.
There were a few others that were close that we
documented in reports and some of those have fallen off the
list as a result of additional work being done by licensees
or additional information becoming available So we don't
believe that there are going to be any further surprises but
that's a difficult issue until all of the information is in
and we see how it's applied.
COMMISSIONER DIAZ: But would you both agree that
we are in better shape?
MR. STROSNIDER: We are in better shape than we
were in '92 and we are getting better and by the time all
the answers come in in '96 and '97, we will be able to
answer it much more definitively, especially for license
renewal purposes. I think that is where it is really going
to be significant as it relates to corrective action for
vessel material properties to operate for an additional
65
period of up to 20 years.
CHAIRMAN JACKSON: From our observer status, at
this point, it is probably premature to ask whether there
are any particular lessons learned from these demonstrations
that need to be passed along in any kind of generic
communications or reg guides? We were talking about the
generic letters in a different context, but --
MR. STROSNIDER: I am not sure about generic
communications. One thing that we are looking at is some of
the same people who did these observations will be
participating in developing a temporary instruction for
inspection when this is implemented.
As we indicated, those observations we had in some
areas like fire protection have certainly been passed on to
Palisades.
CHAIRMAN JACKSON: Any other questions?
[No response.]
CHAIRMAN JACKSON: Well, I would like to thank the
Department of Energy representatives as well as the members
of the NRC staff for briefing the Commission. It appears,
at least, that the results of the project to date are
encouraging and I would urge you to resolve any technical
issues both expeditiously and thoroughly. Sometimes, people
think that is an oxymoron but it is important so that the
public as well as the users of the technology can be
66
confident in the overall process.
Unless there are any further comments, we're
adjourned. Thank you.
[Whereupon, at 3:34 p.m., the briefing was
concluded.]
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