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Home > Electronic Reading Room > Document Collections > Commission Documents > Commission Meetings, Slides, Transcripts, Meeting SRMs, and Full Written Explanation for Closed Meetings > 1997
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05/20/1997
1
UNITED STATES OF AMERICA
NUCLEAR REGULATORY COMMISSION
***
MEETING WITH ADVISORY COMMITTEE
ON NUCLEAR WASTE (ACNW)
***
PUBLIC MEETING
***
Nuclear Regulatory Commission
Commission Hearing Room
11555 Rockville Pike
Rockville, Maryland
Tuesday, May 20, 1997
The Commission met in open session, pursuant to
notice, at 2:00 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
EDWARD McGAFFIGAN, JR., Member of the Commission
. 2
STAFF AND PRESENTERS SEATED AT THE COMMISSION TABLE:
ANNETTE VIETTI-COOK, Assistant Secretary
KAREN D. CYR, General Counsel
PAUL POMEROY, Chairman, ACNW
B. JOHN GARRICK, Vice Chairman, ACNW
GEORGE HORNBERGER, ACNW
WILLIAM HINZE, ACNW
JOHN LARKINS, Executive Director, ACNW
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P R O C E E D I N G S
[2:00 p.m.]
CHAIRMAN JACKSON: Good afternoon.
Today, we are meeting with the Advisory Committee
on Nuclear Waste to be briefed on several technical issues
related to management and disposal of radioactive waste.
The Commission looks to the ACNW, as it is called, to
provide it was sound technical advice to assure the safe
management and disposal of this country's radioactive waste.
Today's briefing will discuss several completed
projects and discuss various issues in the status of two
other works in progress.
In looking over the agenda for today's meeting, it
appears that we have a fairly large number of topics to
cover so, if my fellow commissioners don't have anything
further to add, I will turn it over to you, Dr. Pomeroy, and
we will try to restrain ourselves until we finish each part.
I can't totally guarantee that with this crowd, but we will
try that at any rate.
DR. POMEROY: Thank you, Madam Chairman. We do
have contingency plans, in case there are --
[Laughter.]
DR. POMEROY: Madam Chairman, members of the
Commission, it is a pleasure to be here, as always.
It has been essentially one year since our last
. 4
public discussion and, as you have noted, Madam Chairman, we
have several items of interest that we wish to present. Our
presentations will utilize, as a framework, the current ACNW
priorities and, if we can have the first slide, please,
those are listed. This is Slide Number 3 in the material
that you have.
I would like to briefly run through what our
priority issues are and indicate where we are going to give
presentations within those.
Regulatory framework, there will be a presentation
by Dr. Garrick on the Reference Biosphere and the Critical
Group and if there is time I will talk some about agreement
states issues at the end.
Waste containment and isolation strategy,
essentially we are following that particular issue very
closely and when our timeliness criteria is satisfied we
will move ahead with that. But we are currently waiting for
DOE's document.
Viability assessment and site characterization,
Dr. Hinze will address igneous activity. That is a work in
progress. We are currently in the process of writing a
letter. And Dr. Hornberger will address flow and
radionuclide transport under the site characterization
activity and he will discuss coupled processes under
repository design.
. 5
Low-level waste, radioactive waste disposal. As
noted, you know our views on that subject. We are not going
to discuss those here.
I will talk briefly about decommissioning and
expert judgment, perhaps, with time. Dr. Garrick will
address the question of risk-informed and performance-based
regulation. This is another item that is in progress; it
will be in progress through the summer of this year.
Uranium mill tailings fall under our timeliness criteria and
they are not yet a timely issue for us.
The interim surface storage facilities for spent
fuel, our initial review begins this month.
Moving right along, I would like to turn the
meeting over to Dr. Garrick and he will address risk-
informed performance-based regulation.
DR. GARRICK: Thanks, Paul.
As you know, most of our letters in one way or
another make reference to risk-informed performance-based
regulation and our letters certainly support that approach.
While we haven't written a letter explicitly on this
subject, given the frequent reference to it we thought it
would be a good idea to discuss it some and to share with
you some of our thinking on this subject and to address a
couple of specific questions which I will get to in a
minute.
. 6
As far as risk-informed performance-based
regulation is concerned and its use in the nuclear waste
field, there are a number of factors that certainly favor
that. Compliance demonstration is already rooted in meeting
performance requirements. The EPA standards or regulations
have a risk-based quality to them.
The regulatory standard, at least for high-level
waste, is in fact probabilistic.
Regulations covering high-level waste are evolving
with the anticipated first license application for a high-
level waste repository, thus the timing seems to be good for
us to do something constructive and useful here.
The PRA policy statement and the PRA
implementation plan sets the framework for staff uses of PA
and PRA.
As far as factors to overcome to implement RIPB
regulation in the nuclear waste field, you have heard a lot
about these. You have heard a lot about the comparisons
between PA and PRA and so I am not going to repeat that
because those presentations were very excellent in that
regard. I am going to give a little bit of an ACNW spin on
them, however, and maybe touch on a couple of items that
were not covered before.
So as far as some of the obstacles are concerned,
number one, risk assessment experience of NRC is principally
. 7
in the nuclear power field. The facility differences
between nuclear power plants and repositories are extensive
and thus there is a compromising of the relevancy of the
experience base.
Engineered systems involving active equipment and
hardware have been the principal target for the development
of the analytical methods of risk assessment, although the
level two, that is the containment and core response work,
has many aspects to it that are similar to the performance
assessment modeling challenges.
PRA started as a risk-based discipline, PA did
not. Probabilistic features have been evolving in PA.
So one way to get to this question is to pick up
on some of the things you have already heard a little bit
about, as I said, and give it our spin. So let's pose the
question: How can PRA approaches, methodologies and
techniques be brought to bear on Pas?
Well, as far as the basic issue is concerned of
what is the risk, we have to, through PA or PRA, answer the
same fundamental three questions. What can go wrong, how
likely is it and what are the consequences. So the basics
are the same.
Now, while I promise not to get too much into the
comparisons, I want to repeat some that you have heard about
and comment on them a little bit.
. 8
As to similarities, both PRA and PA are scenario
based. Now, I am speaking here more from the point of view
of a practitioner in PRA in many respects than I am an
expert on PA, which I am not. I am also speaking
principally from the point of view of practitioner on the
industry side when it comes to PRA and on the industry side,
there is a considerable amount of emphasis on the risk
assessments being scenario based.
The scenarios of both require definitions of
initial states and end states. In order to have a scenario,
you have to have a beginning and you have to have an end.
Both have ultimate risk measures that involve health effects
from radiation and both involve the philosophy of defense in
depth.
Now, as far as the dissimilarities of PAs and PRAs
are concerned, in general they are very dissimilar with
respect to the roles of active and passive systems. The PA
being principally an analysis of a system where the
subsystems are passive. The nuclear power and the PRA being
born in an environment where most of the systems are active,
although there are examples of passive systems.
There is the issue of accidents versus
performance. The emphasis in nuclear plant risk assessment
work is the analysis of rare and high-consequence accidents.
In fact, that was the motivation for risk assessment.
. 9
Versus the repository emphasis on long-term performance.
There are considerable differences with respect to
the time cycles, the time constants, the time constraints
involved. Generally, the time constants associated with
high consequence accidents in nuclear power plants is short
compared to the time constants associated with the
degradation of a repository.
There is the issue of safety goals for the case of
nuclear power plants and no safety goals for the case of
repositories.
There is the issue of unconditional risk versus
conditional risk. By that, I mean the reactor risk
assessments are, for the most part, unconditional in that
they are not -- the risk calculations are not under the
assumption of any particular initiating condition.
There is the issue of degradation rates versus
failure rates. While the repositories have a slow change in
their integrity, most of the accidents associated with
nuclear power plants involve changes that happen over short
periods of time, although there are the issues of aging and
the issues, again, of some of the passive systems where
there is a gradual degradation.
Now, what can we get from PRA that will help us in
doing performance assessments? And I like to call them
PPAs, probabilistic performance assessments.
. 10
Well, one of the things that we do in PRA that is
very helpful from a model transparency standpoint is segment
the problem into logical modules. In the old days, we used
to call the modules the plant model, the containment model
and the site model. The output from the plant model was a
series of damage states that became the input to the
containment model, the output of which was a series of
release dates that became the input to the site model. So
these were very logical pinch points that would allow us to
analyze each of these segments independent of the other once
we determined what these end states were.
The repository problem model lends itself to some
of this same sort of thing. I will come back to that in a
minute.
Data processing in the form of the results. In
the PRA arena, there has been a great deal more dependence
on Bayesian type methods for processing data and accounting
for the effect of new information and taking into account
the update of information as it becomes available. And the
data processing was, for the most part, based on information
quality with some of it based on modeling quality. But one
of the things about the repository modeling that I have
observed is that they are giving more attention to modeling
uncertainties than at a similar time was given in the case
of the nuclear PRAs.
. 11
The adoption of multiple risk measures. In the
case of particularly the early PRAs of nuclear power plants,
a full-scope, level three risk assessment involved maybe as
many as nine measures of risk. I sort of like to draw an
analogy between a skyscraper and a risk assessment that you
learn something by looking in one of the windows of a
skyscraper but not much. You learn something about the risk
of a nuclear power plant by looking at the core damage
frequency but not much. It is much more informative to have
multiple measures of risk and each time you learn something
in addition.
The PRA experience in the nuclear plants that has
been extremely beneficial and I think is a concept that has
been reasonably well picked up in the repository is this
business of importance ranking. You can rank scenarios, you
can rank the initiating conditions and you can rank by other
things that contribute to the risk.
So what I would like to do, and I have to
apologize for this diagram, it is a little complex, but it
helps me drive home this point of where we might look for
enhancements in the repository risk assessments on the basis
of our experience in the risk assessment of other
facilities.
What this attempts to do is to modularize the
performance assessment into particular segments, much like
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the three segments that the nuclear plant is modularized.
As a matter of fact, you might even draw an analog between
the infiltration model here and the plant model and the
combination of the engineered barrier model and the
geosphere model as the containment model and then, of
course, the biosphere model as an analog with the
atmospheric dispersion or site model.
The modeling concept that was extremely helpful in
enhancing the understanding of what was going on was when
you did this, defining your output states from each of these
modules in such a way that they indeed became the input
states for the succeeding part of the model. So the
infiltration model would have output states that would be
defined on the basis of physical and chemical properties.
You may have one state define on the basis of a certain
temperature pressure and a certain chemical makeup of the
water flow and so on. And this is where there is a major
difference between PRA and PA in that when you do this, of
course, the actual scenarios that you end up with are
developed as a result of this process rather than doing it
as it is often done in the case of a repository where you
actually establish the scenarios in advance from end to end.
So this is an interesting thought that we are
going to examine in a working group in a couple of months as
to whether or not there would be any merit in structuring
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the scenarios in this slightly different manner.
One other thing that I wanted to point out here is
the question is if I wanted to -- if I wanted to see a
repository analysis in a form that I would classify as risk
informed and performance based, what kind of measures would
I look for? My last exhibit there is just an attempt to
delineate some of those.
One of those measures would be the dose profile,
the dose rate profile, for example, the upper left-hand
corner. Dose rate curve as a function of time, such that I
have the entire profile available to me, as well as the
uncertainty associated with it.
Now, this is a little different kind of
presentation than normally one thinks of in a risk
assessment because here we are talking about dose rate, we
are not talking about the frequency of occurrence of an
event or what have you. But I like to kind of observe that
what I really mean by a risk assessment is not deterministic
versus a probabilistic but rather a deterministic plus
probabilistic that what you really -- what you really get
out of a risk assessment is another dimension. You get an
expression of the confidence that the analyst has in their
results. The issue of parameters or models, parameters of
the models, that is another matter.
The second curve in the upper right-hand corner is
. 14
typical of what you might get as a source term curve as a
function of time. Of course, you may want to look at
discrete points in time in terms of how the uncertainty
grows with time in a little more detail than would be given
by that curve and that is the idea of the third set of
probability density functions.
Then the fourth curve here, if I were giving this
as a homework assignment and wanted to really see what was
going on, I would ask for a risk curve on each of the
disruptive events because they do assume a frequency
character to them and therefore I can use the full arsenal
of all of the PRA software to help me calculate a cumulative
probability density distribution, complementary cumulative
density distribution for each of the disruptive events.
Now, if we choose and desire to combine these into
a single parameter for measuring risk, that's fine. But I
think one of the things we have learned in the risk
assessment business where it has matured some is that it
sometimes gives you very important insights to not convolute
and combine everything but to let it kind of speak for
itself.
So this is just a few thoughts on where we are and
what we have been thinking about.
CHAIRMAN JACKSON: Thank you.
Commissioner Rogers?
. 15
COMMISSIONER ROGERS: Where do you see it going
from here?
DR. GARRICK: That's a good question.
Well, I have been in this business a long time. I
have seen it go quite a way but I have never seen it go
anywhere without a fight; that is to say, a tremendous
challenge.
I think that I have seen an enormous amount of
progress in the IPA work just in the last two years in
embracing the notions of probability into the models so I
think it is moving in that direction and I think there is a
lot of shaking out yet to do and some of the things we are
talking about here are candidates for how it might shake
out.
CHAIRMAN JACKSON: Commissioner Dicus?
COMMISSIONER DICUS: No questions.
CHAIRMAN JACKSON: Commissioner McGaffigan?
COMMISSIONER McGAFFIGAN: No questions.
CHAIRMAN JACKSON: You are off the hook easy.
DR. GARRICK: That is much easier than I had
expected.
[Laughter.]
DR. POMEROY: If not, then I would like to keep
Dr. Garrick talking, if I may. In Tab B.2 of your book, we
have a presentation on the reference biosphere and the
. 16
critical group.
Dr. Garrick will carry that on.
DR. GARRICK: Well, this is an issue on which we
did write a letter. The way we have sort of approached it,
and this is also an issue where, of all the issues this
committee has addressed, I don't know that I can remember
one where there was greater involvement by all members of
the committee than on this one. So I am not on the spot
here; the whole committee is on the spot and I expect them
to speak up.
But we approached this from the point of view of
what are the real questions here and the questions that we
see are, first off, what's the issue and is there an
overarching one and what is the essence of our advice and
what is the basis for that advice.
Now, the question, as we see it, is basically the
exposure scenario that should form the basis for
demonstrating compliance at the proposed Yucca Mountain
high-level waste repository. This is a subject that has
gotten a tremendous amount of attention. It was the central
issue with respect to the National Academy of Sciences
committee that looked at the technical basis for the high-
level waste repository standard.
Embedded in this issue, as it was so clearly
manifested in that report, are the definitions of the
. 17
reference biosphere, the critical group and the previously
defined time of compliance. Now, we supplied you with a
letter on time of compliance so we are not going to say much
about that today.
As far as our advice on this issue is concerned,
it took the form of first trying to be generic in terms of
some definitions for the reference biosphere and the
critical group and to attempt as best we could to address
the whole issue as much on a scientific basis as we could
but recognizing that there were gaps in our scientific
knowledge and that those gaps would most likely have to be
dependent upon the establishment of policy.
We also gave a lot of attention and emphasis to
the importance of the staff taking advantage of known site
characteristics and repository design features to provide
increased focus on the questions, to provide every
opportunity possible to reduce the uncertainties. This was
an opportunity to do that. Seldom do you get in the
position of creating a regulatory framework for a single
facility. Then, finally, we offered some suggestions with
respect to some basic principles for calculating and
interpreting risk measures.
Now, as to the essence of our advice, we kind of
came to the conclusion that what we meant by the reference
biosphere was the environment in which the biota and the
. 18
critical group comes in contact with radionuclides. As far
as the critical group is concerned, we indicated that that
is the population group that forms the basis for calculating
the radiation risk to the public and including but is not
limited to the person or the individual at greatest risk.
As far as the policy requirement is concerned, the
area where there was clearly some scientific gaps was the
basis for defining demographics and behavior of populations
that are at risk from the repository over the time period of
compliance.
Site specificity, again, we urged the use of known
site and design characteristics to generate regulations and
guidance that will reduce technical uncertainties and
increase confidence in the assessment of the safety and
overall performance. Now, we talked about risk assessment
principles, made reference to the issue of consistency of
application of risk-based methods and what we meant by that
was primarily that if you are, for example, examining a
scenario it is wise, we think, if you are taking a risk-
based approach to do that throughout the entire scenario
rather than applying it in some modules and not in other
modules. But it is something that we put quite a bit of
emphasis on.
Now, the basis for our advice and the theme of our
letter was that the whole issue of the reference biosphere,
. 19
the critical group, should be as much scientifically based
as it possibly can be and we should push that to the limit.
Whatever we come up with as science is developed that
reduces the dependence on policy, we should be able to take
advantage of that science.
So policies only where there are scientific gaps.
We also, as we have in most of our advisory letters of late,
emphasized the need for the adoption of a risk-informed and
performance-based approach and, as I said, we also pushed
the notion of consistency of application.
CHAIRMAN JACKSON: How easy do you think it would
be to come to real unanimous or near unanimous agreement on
what items would constitute scientific gaps?
DR. GARRICK: Well, I think that there is fairly
good agreement as to where we are lacking sufficient
scientific information to put forth what we would call a
scientific basis and I think we have identified that. I
think that one of the things I have been encouraged by in
the repository work as I have gotten more involved in it is
that the well designed research program, well orchestrated
analysis program can provide a lot more information than I
suspect many of us thought would be possible.
So the only area that I think we are uncomfortable
with, with respect to a scientific gap, is the area having
to do with the demographics of the future and the human
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behavior in the future.
DR. HINZE: Not to be flippant, but it is going to
be a lot easier to determine what the gaps are than to
arrive at a policy. I think that is clear as one looks at
the problem.
DR. POMEROY: And I think there is another aspect
that I would like to emphasize and that is that the policy
decision is going to be very, very serious in certain of
these areas. The location of the critical group, which may
be specified by the EPA, may be specified by the NRC or it
may be specified in some ways and offered to you at the
staff level.
That choice alone can determine the acceptability
or nonacceptability of a given repository in a generic sense
and we have examples of that that we could discuss.
DR. GARRICK: I think there is another point that
is important, since there has been a lot of discussion about
uncertainty. If one adopts the notion of the science of
uncertainty, that is to say accepts the fact that if some
parameters are going to involve considerable uncertainty, as
long as you represent that uncertainty in your modeling and,
as some of us like to call it, tell the truth, it is
possible to stretch the scientific basis considerably beyond
what you might otherwise think is possible.
One of the things I think we have an illusion
. 21
about is that when we are working with a point estimate that
we are working with truth or that we are working with
complete knowledge. Seldom in the kind of work that I have
been involved with, at least, has that luxury really
existed.
So I think that we are not in as bad a shape there
as we might and if there was any kind of information that
developed that would allow us to represent even future
demographics in terms of some parameters, albeit they would
have large uncertainty bands, that would, at least, even
there be a step toward bringing science into that process
and we should certainly, in whatever regulations we evolve,
accommodate that possibility.
CHAIRMAN JACKSON: Commissioner Rogers?
COMMISSIONER ROGERS: No, I think the questions so
far were what I had.
CHAIRMAN JACKSON: Commissioner Dicus?
COMMISSIONER DICUS: Let me try to clarify
something to be sure I understand it and this is on the
scientific gaps and clearly you identified at least one area
where policy requirement might come in on the demographics
and the behavior of populations. And I wasn't clear as to
whether or not that is the only place you have identified or
you have identified others already or you think there will
be other gaps.
. 22
DR. GARRICK: Well, there are others that are
often talked about as bordering on scientific gaps. One of
those activities that we have already mentioned is the issue
of disruptive events and the role of disruptive events.
Clearly, there is considerable uncertainty in the
frequency and severity, that is to say the hazard curve,
associated with the large earthquakes, large magnitude
earthquakes. Similarly, you could say the same thing with
respect to igneous events and you could say the same thing
with respect to other things that --
DR. HINZE: Human intrusion.
DR. GARRICK: Yes, human intrusion, meteorites,
whatever. So those are all candidates for scientific gaps.
On the other hand, I think that we have made a considerable
progress in how to at least include them in our modeling.
It is like the whole arena of the risk business. We first
learn how to model active systems and then we started
working on so-called external threats, such as earthquakes
and storms. But we know how to do this active system
modeling better than we know how to do external events,
better than we know how to do human response, better than we
know how to do organizational performance and so on.
So it is a gradual encroachment on these things
that all contribute to the risk in bringing them into the
technical arena and making them less subjective and more a
. 23
part of the analysis based on some sort of evidence. And if
your modeling activity accommodates the treatment of
parameters that have high uncertainty in them, there are
quite a few things that you can do that you otherwise
couldn't.
DR. HORNBERGER: Could I interject something to
disagree just a little bit with John, which I'm fond of
doing?
DR. GARRICK: They all are.
[Laughter.]
DR. HORNBERGER: Scientific gaps doesn't quite
capture what we have in mind because scientists, as a
scientist, we are fond of talking about gaps in science
where we need more research dollars to close the gaps and I
don't think that is primarily what we are talking about.
Earthquake frequency, there is some chance that
science will get us better and better answers in the future.
I don't think that we are going to get better and better
answers from science on human intrusion scenarios. And they
are the kind of things that I believe that we, the ACNW, was
focusing on where policy was really needed.
DR. HINZE: If I might interject, one of the
problems there is the location of the critical group. That
is something where we can have some scientific input but,
yet, it is going to be a policy decision. There is
. 24
scientific information regarding the depth of the water
table, for example, and how the water table may vary with
climate and thus the economics of the critical group. But
this really fades into the policy area.
As much as possible, our message is use science as
much as possible and then your best judgment in terms of
policy from there on.
CHAIRMAN JACKSON: Commissioner McGaffigan?
COMMISSIONER McGAFFIGAN: Could I ask on the
question of policy issues, both bills currently pending
before the Congress try to settle at least some of these
issues, assuming that is in their view the best way to
settle it. Have you looked at the bills and seen whether --
human intrusion, for example, is dealt with in both
bills -- and reached any conclusions as to whether they are
dealing with these policy issues, these scientific gaps as
the term was previously used?
DR. GARRICK: I am generally familiar with the
bills and, yes, they would have a major impact in my
opinion, because they address both the standard question,
the issue of the dose levels and they also address the
interim storage. The interim storage has an impact on the
repository because it gives you an opportunity to do things
with the feed material to the repository that you wouldn't
otherwise be able to do. So, no question in my mind, that
. 25
these bills are going to have a major impact if they are
approved. At least that's my view.
COMMISSIONER McGAFFIGAN: But have you looked at
whether there are additional policy issues that, in your
view, need to be resolved? That was one of the questions
that I believe our staff received from both houses was, are
the policy issues that need to be settled being settled in
this bill or are there gaps that we should think about
settling?
DR. GARRICK: Well, I think the policy issue that
prevails is the same one that we have been talking about.
COMMISSIONER McGAFFIGAN: Human intrusion?
DR. GARRICK: Right.
DR. POMEROY: There are certainly, however, going
to be significant issues that arise in any interim storage
facility with regard to the infrequent events, particularly
seismology and volcanology.
With your permission then, we would like to turn
next to a presentation on flow and radionuclide transport
and coupled processes by Dr. Hornberger.
DR. HORNBERGER: Given my profession, I am not
sure how coherent a presentation I can give without a
chalkboard behind me and a piece of chalk in my hand.
COMMISSIONER DICUS: We can arrange that.
CHAIRMAN JACKSON: I made the migration.
. 26
[Laughter.]
DR. HORNBERGER: The issue of radionuclide
transport and coupled processes, these two issues, I think
are clearly recognized not only by our committee as
important but quite broadly by people in the business. They
are key elements in the evaluation of Yucca Mountain as a
potential repository site. Both the transport of
radionuclides through the vadose zone and through the
groundwater pathways in the saturated zone and the
interaction of radionuclides with the rocks themselves and
recognizing this importance of radionuclide transport, we
held a working group meeting in September of 1996 where we
heard presentations by a variety of groups on these issues.
I wanted to cover just a bit about the significant
issues that came up at our meeting in Las Vegas. One of
these, I am sure that you heard probably repeatedly about
was the measurement of bomb-pulse chlorine 36 in the ESF.
These values are, the elevated values of chlorine 36 are
obviously attributed to or can only be interpreted as caused
by the flow of water to the level of the repository horizon
within the past 50 years, roughly. This is very rapid for
flow in the vadose zone at Yucca Mountain and indicates that
there is flow and transport in an interconnected series of
fractures and faults at Yucca Mountain.
This, of course, really is a significant issue for
. 27
evaluation at Yucca Mountain because it is a difficult -- it
is difficult to measure, it is difficult to model, all of
the things that have to be done.
CHAIRMAN JACKSON: When Mr. Barrett from
DOE -- I'm sorry to interrupt you -- briefed the Commission
last week, he seemed to think that these were things that
could be engineered around. Has the committee come to any
conclusions?
DR. HORNBERGER: The preliminary data we have
seen, there is a graph, if you can put up the chlorine 36,
on the graph on page 16 in your handout, you can see that
these open squares, the ones that are high -- by the way,
the background, the dotted line at the bottom is the current
background. But, in the past, because of changing
conditions there had been elevated levels of chlorine 36 so
that really anything below about 1,500 on that left-hand
scale can be ruled out as not being bomb-pulse. So it is
really these higher values that are important.
The open squares indicate data that were collected
on what DOE refers to as a feature basis. That is, they
went along and they identified fault zones and that is where
they took the samples. And you can see, for the most part,
the elevated values of chlorine 36 are associated with these
features. That is the basis, I think, of Lake Barrett's
conclusion, if we stay away from major fault zones, we may
. 28
be able to avoid these fast flow paths.
Now, having said that, I don't think that the
final story has yet been written. There are a variety of
isotopes that have to be looked at and we have to hear a lot
more about the distances from these fault features where the
chlorine 36 has been identified. I think at first blush it
looks like an engineering solution might be feasible but it
is a little too early for me to say that with any degree of
conviction.
I think what the chlorine 36 data touch on as
well, or in coordination with another significant issue that
came up at the meeting, is that the infiltration flux
through the repository horizon is a really important
parameter in determining the performance assessment. DOE
had originally speculated that the infiltration rates were
very low, the fluxes were very low. From a host of
different lines of evidence, this number has been revised
and best estimates now are probably that the flux is between
one and 10 millimeters per year whereas earlier estimates
had placed it at less than one millimeter per year.
This then has significant implications for, as I
say, the repository performance, the evaluation of the
repository performance. And there is a significant issue as
to how much information we have and how much more
information we need. I am using the "we" generically. DOE
. 29
needs to actually evaluate repository performance. There is
precious little actual data on the hydrological
characteristics of fractures and faults at Yucca Mountain.
Some other issues that came up at our working
group meeting have to do with the chemical state at the
repository. It was unclear to us from the presentations we
heard to what extent DOE and their contractors were dealing
in an integrated way with what we might term the near field
chemistry, the fact that there were going to be large
quantities of iron, steel, concrete in the repository and
actually trying to come to grips with how these materials
might buffer the chemistry, the dissolution of the waste
forms, the waste packages themselves.
Furthermore, it turns out that with the higher
fluxes now being looked at, higher infiltration fluxes
through the repository horizon, the importance of the
interaction between the radionuclides and the geological
materials, the zeolites, the absorption, the geochemical
interaction may in fact become more important than
previously thought. This is an issue that may assume
greater importance in the future.
Finally, we heard some material on colloid
transport and we were not convinced that this issue had been
resolved, the effect of colloids.
Concerns and advice? Well, in addition to some of
. 30
the other concerns that I hinted at, we had a fairly
significant concern that DOE and the contractors were
developing some very nice what we might call inverted,
scientific models. But clearly to go to performance
assessment, TSPA, their TSPA, they are going to have to do
abstractions. They are going to have to use
simplifications. We were concerned about the transparency
of that simplification process. In fact, our advice to NRC
staff was that the staff really needed to remain aware of
both the expert elicitation process and the TSPA abstraction
workshops to make sure that they kept tabs on how DOE was
doing this so that they would understand the simplifications
that had gone on.
The ACNW is concerned about the limitations that
had to be placed on the issues related to radionuclide
transport at the center. We recognize, really along with
the NRC staff, we do understand how these decisions come to
be made. But, again, I think you heard from Margaret
Federline the ongoing analysis may in fact lead staff to
have to revisit this issue and perhaps revive some of the
work that had been put on hold regarding radionuclide
transport.
We also had thought that the NRC had supported
work at the Apache Lead Research Site at the University of
Arizona for many years and we saw a chance that some of
. 31
these issues related to colloid transport in particular
might be effectively dealt with by additional work at the
ALRS.
Finally, I have just a few words to say on coupled
processes. You might say I have been talking about coupled
processes, hydrology and geochemistry, and that is true.
There are other coupled processes that are of some
importance.
In particular, the focus on the near field having
to do with thermal load in particular, the ACNW sees -- we
anticipate that there will be increased use of PA to
prioritize emphasis on coupled processes and really to do
scoping studies as to really what new data may need to be
collected. We see in the letter report that we sent
forward, we see this as an area that is "data starved." We
have more models than we have data and we think that more
data are going to be necessary.
As I mentioned earlier, we see a need for greater
emphasis on near field chemistry and also we see a need to
keep tabs on the repository design in terms of the thermal
load. This has not been set and a linkage between the
thermal load and the hydrological response is likely to be a
key issue.
That is all I have to say.
CHAIRMAN JACKSON: Zero sum game budgeting can
. 32
result in the support of one area of research resulting in
eliminating another. So is there an issue under review by
the center, the CNWRA, that you would propose being replaced
by the work on flow and radionuclide transport and the
coupled chemical and hydrologic transport models?
DR. HORNBERGER: You saved the tough question for
me, didn't you?
CHAIRMAN JACKSON: I warm up as I go along.
[Laughter.]
DR. HORNBERGER: Obviously, I would have to be
very careful in terms of we haven't done a very -- I haven't
done a very full analysis of the total center program so I
will just give you my own opinion. This is not an ACNW
opinion.
I think that, for example, we heard --
CHAIRMAN JACKSON: Commissioner Dicus is giving me
a look.
DR. HORNBERGER: Okay.
[Laughter.]
DR. HORNBERGER: We heard about the KTI and
igneous activity at our last meeting and we actually, I
think, there is room for an orderly closeout, for example,
on that issue. I don't know what kind of resources that
would save. I don't know whether that would really lead to
an improvement of the situation with regard to radionuclide
. 33
transport or not but in a zero sum game there aren't any
easy choices.
CHAIRMAN JACKSON: Thank you.
Commissioner Rogers?
COMMISSIONER ROGERS: Is there any work going on
elsewhere in the world that we might be able to tap into,
particularly on these more general questions of coupled
processes and colloid chemistry effects?
DR. HORNBERGER: Yes. Colloids and coupled
processes have been an emphasis internationally. The
difficult bit is, for example, with colloid transport is, to
my knowledge, all of the other countries in the world are
looking at saturated repositories. So we can learn some
things.
It turns out, however, that colloids have a
propensity to get hung up on air/water interfaces and you
don't have very many air/water interfaces in a saturated
granite. So there are some limitations.
So the short answer is, yes, there is a lot to
learn. We should definitely keep abreast of what is going
on internationally. But there are also some very special
things going on a Yucca Mountain.
COMMISSIONER ROGERS: Do you think there are any
mechanisms that ought to be put in place to tap these
international efforts that are not presently available?
. 34
DR. HINZE: One of the things we stated in our
coupled process letter is that INTERVAL, the second phase of
INTERVAL has a lot of merit and a lot to tell the NRC and
the center in our work. One of our recommendations was
there seemed to be a lot of bang for the buck, if you will
permit me, a lot of things that could be achieved with
relatively minor investment. That would also, of course,
give the NRC a certain amount of leverage in terms of
directing that into those areas that would be of most
interest and most concern to a tuff-related repository.
CHAIRMAN JACKSON: Commissioner Dicus?
COMMISSIONER DICUS: Yes, you have pointed and
spoken to the importance of the transport and the findings
with chlorine 36 and I think in response to the Chairman's
question regarding engineering features to perhaps address
or resolve the issue. My question goes to more of a shorter
term. Would you care to make a comment on what these
findings, what might their implications be with the
viability assessment?
DR. HORNBERGER: I think that these
provide -- these are data that everyone has to take into
account. There are two issues, of course. The presence of
chlorine 36, of course, indicates there is new water but it
doesn't tell us how much new water. Now, the suspicion from
the range of other investigations is that the flux is very
. 35
small so we are not necessarily talking about a leaking
sieve so I think that DOE will certainly have to bound the
uncertainties and they will have to investigate this in
their viability assessment. But I don't think that this one
bit of evidence says, all bets are off, it has to be purely
engineering that we rely on.
CHAIRMAN JACKSON: Commissioner McGaffigan?
COMMISSIONER McGAFFIGAN: Just on the issue of
funding, when we had Mrs. Federline in a few weeks ago,
radionuclide transport was an area where she identified some
extra money might be needed. The Chairman has -- I forget
whether it is vapors or fumes -- has said our program is
working on in a few areas and we clearly hope that we will
get some support from the Congress this year to get the full
$17 million request and get -- my sense is even if we can
close out, if that is appropriate, the igneous activity,
KTI, we still have lots of things where new issues are
coming up that we could usefully put some resources into,
totally leaving aside an interim storage site if that ever
were to emerge. We are totally working on fumes at the
moment or darn close to it.
So I just wanted -- the Commission has made it
very clear and in testimony, the Chairman's testimony, even
at $17 million, we have a very, very, very tightly
constrained program.
. 36
That's more a statement than a question.
DR. HINZE: I would like to interject something
about coupled processes in relationship to that. One of the
reasons that we looked at coupled processes is the committee
was concerned that there was not a KTI on coupled processes
because we think that is a very important item. The Staff
folded this into the technical integration, KTI.
But our concern here was that we don't lose the
coupled processes because this is potentially extremely
important and that the resources, as you were alluding to,
are a problem there too. But at least coupled processes are
being worked upon in that technical integration. It is a
matter of emphasis.
CHAIRMAN JACKSON: Dr. Pomeroy.
DR. POMEROY: We will move right along.
The next item on our agenda has to do with igneous
activity and Dr. Hinze will make that presentation. That is
under Tab C.1.
DR. HINZE: Since the bottom line has already been
given on this --
[Laughter.]
DR. HINZE: Thanks George.
As I think we are all aware, the potential risk
from igneous activity has been identified as an important
site characterization issue and is appropriately a KTI and
. 37
that is because Yucca Mountain lies within what is known as
an active volcanic field. Anyone that travels, as you have,
to the site sees Lathrop Wells, which has an age date of
100,000 years and perhaps even some less, activity that is
less, that is only 15 kilometers away. And we see some of
the one-million-year-old activity of Crater Flat, just five
miles, eight kilometers away from the site.
Obviously, this makes the likelihood of activity,
the probability, extremely important. That, together with
the possible entrainment of waste in an eruption could bring
waste to the surface and that brings us to the consequences,
the other half of the risk ingredient. Additionally, there
could be some igneous effect, igneous activity effects that
would be indirect and these are part of the coupled process
routine as well.
I am sure the Commission is very well aware that
historically this is a contentious issue which has reached
the popular as well as the scientific press. The major
players in this, the three major players, DOE, NRC, as well
as the state of Nevada, have all had somewhat differing
views which seem to be approaching some kind of commonality.
Not exactly commonality, though.
It is important to understand that the reason for
this is that the science of prediction of volcanic activity
or igneous activity, especially in terms of thousands or
. 38
tens of thousands of years, is really very much in its
infancy. It is a difficult problem. And as a result of
this limited experience in prediction and also the very low
number of igneous events, it works at you both ways there.
There are a lot number of igneous events and, as a result,
the Yucca Mountain -- the approach to Yucca Mountain igneous
activity problem requires that we approach this
statistically, look at probability and be very much
concerned about the range of uncertainty.
In the next slide, we mentioned a few things
regarding our activities. We have been long supporters of a
strong NRC program on this topic for confirmatory purposes
and have continued to monitor it. And, as mentioned
previously, we did hold a meeting, at are last meeting in
April, to examine the status of the igneous activity KTI
because we are at really a critical stage in that whole
process. We were joined by several international experts in
volcanology who gave us advice.
The bottom line to all of this is that we believe
that the ACNW should -- we conclude that the work on this
topic of igneous activity is very much nearing completion
and should be brought to an orderly closure within roughly a
year. We do have some recommendations for that program and
we will -- we are in the process of preparing that in the
form of a letter to you which hopefully we will have out at
. 39
this meeting.
In terms of the status of the igneous activity and
in terms of probability specifically, DOE has closed out its
site characterization program with the probabilistic
volcanic hazard expert elicitation which, incidentally, came
up with about the same mean probability value that the DOE
program did. They have also closed out their work on the
consequence, the other half, the consequence study.
We don't know very much about that. They have not
made presentations to us on their work on this but the
synthesis report that they are preparing and will be out at
the end of the fiscal year, we are told, will provide us
with that kind of information.
Now, DOE and NRC and practically every individual
scientist because of the infancy of this "science" have
different approaches to estimating the probability. But
peer reviewed literature indicates that these are -- that
these may all be viable approaches but they are different.
And DOE and the NRC don't reach the precise probability
value.
The significance of this is important to all of us
but it is going to have to wait for follow-on PA work both
by DOE and by NRC to put it into the risk RIPB, to the risk-
informed, performance-based approach.
The NRC has performed preliminary consequence
. 40
estimates. These are excellent preliminary work. The DOE
is in the planning stages on this and will be taking this up
as part of their TSPA and, as we understand from them, they
will be using basically the same codes that the NRC is using
in their calculation of risk and those consequence and thus
risk.
The NRC continues to fine-tune their work and
appropriately they are conducting and should for a short
time here should conduct limited -- in our view should
conduct limited field work and they are conducting modeling
studies to decrease that uncertainty and to test the
conceptual models. That is true in both the probability and
consequence areas.
I am sure you have heard from DOE and from your
own staff the results. Let's just touch on those again.
The tentative estimates, and these are still tentative
estimates because they are not completely documented and
finalized. But the probability is that there -- from the
multiple models of the staff and the center have a range of
probability of 10 E-7 to 10 E-8 events per year. And what
the NRC staff needs to do, in our view, is that they need to
finalize this and they also need to develop their range of
uncertainty of that value from their studies, from their
studies of the models.
Consequences have been performed leading to 500
. 41
millirems per year at 20 kilometers at Amargosa Valley.
This is from a particular model that deals with waste
entrained in an ash-forming eruption. This is -- they have
used relatively conservative values in their calculation of
this.
The net result, when you look at the risk here for
a period of 10,000 years, you end up with a risk that gives
you that warm, fuzzy feeling of half a millirem per year
over a 10,000-year period of time.
The DOE has estimated as a result of their PVHA a
mean probability of 1.5 times E-8 with a bounding range of
10 E-7 to 10 E-10. The PVH estimate and the DOE estimates
are something less than an order of magnitude difference.
My own personal feeling, and this is my personal feeling, is
that considering the fact that the risk is only half a
millirem per year based upon the 10 E-7 value, which the
staff terms a reasonably conservative upper bound, that the
difference here between the PVHA value and the work of your
staff is not remarkably different and not terribly
significant.
In terms of our conclusions, this is not just the
perfunctory congratulatory but we do believe that the NRC
has had a very strong program that provides excellent
confirmatory expertise. This is a new area and their chaps
have really bitten into this and done an excellent job, peer
. 42
reviewed articles, et cetera, that have been very well
received.
The probability and consequence activities of the
NRC need to be prioritized. The work needs to be conducted
with dispatch and leading to an orderly closure within a
year and that should include complete documentation. We
need more documentation.
In order to have some robustness to these results
and to have confidence in them, it is important that the
probability studies be scrutinized with sensitivity studies
and there is a need, potentially a need for the igneous
event sites that have been recognized in the immediate Yucca
Mountain area, and particularly in Jackass Flats immediately
to the east of the repository, these need to be checked out
to determine if we have the presence of unrecognized
volcanic igneous activity events. This is the one
possibility of having a major change, bringing about a major
change in the probability. This is not calling for a great
deal of work and it would make the results much more robust
in the licensing procedure.
Consequence studies are preliminary. We need to
have a little more complete range of the scenarios. We
don't mean ad infinitum but there needs to be a look at
broader scope of the scenarios, particularly the spatial
gradient, the study of the spatial gradient of the dose in
. 43
an ash eruption type of eruption. And any study of any
vagaries in the distribution of the ash by wind, for
example, we all see the sand dunes in Amargosa Valley and we
must be certain that the distribution by winds, for example,
may not complicate the situation.
We don't mean to be harping but greater reliance
on PA is needed to prioritize the activities in the igneous
activity and it still is possible to do that and make that
more worthwhile. And also we need some guidance on this
particular KTI, on closure of it. What uncertainties are
going to be permissible for closure of this KTI?
We do want to pass on the recommendation that
there is a need to maintain expertise in igneous activity,
to monitor and evaluate the continuing scientific progress
in predicting igneous events. This is a very dynamic area,
one in which the science is changing at a very steep -- on a
very steep gradient and it is possible, I don't know about
probable, but certainly it is possible that in this
prelicensing period we are going to see some significant
changes in the ability to predict igneous events.
So it is important that we maintain an expertise
to follow that, to evaluate that and to also be involved in
the monitoring of the TSPA-VA of the Department of Energy as
well as handling the NRC's own performance assessment work.
We will hopefully be providing you with comments
. 44
and discussion about these individual items, but would be
happy to try to answer any questions.
CHAIRMAN JACKSON: Commissioner Rogers?
COMMISSIONER ROGERS: I have no additional
questions.
CHAIRMAN JACKSON: Commissioner Dicus?
COMMISSIONER DICUS: No questions.
CHAIRMAN JACKSON: Commissioner McGaffigan?
COMMISSIONER McGAFFIGAN: Again, a comment.
Another reason we may need to maintain expertise is when we
ever get a license application in this area we need someone
who remembers why we closed it out the way we did in 1998.
DR. HINZE: Yes, sir. And I think my colleagues
said that I should say "documentation" at least five times
during my presentation. I don't know whether I made five
times but I wanted to.
CHAIRMAN JACKSON: So that in the year 2040, we
can --
[Laughter.]
DR. HINZE: Well, we won't see it.
Thank you very much.
CHAIRMAN JACKSON: Thank you.
Dr. Pomeroy?
DR. POMEROY: I would only like to reemphasize one
point that Bill made. That, again, the spatial distribution
. 45
and the sensitivity studies in the igneous activity area are
extremely important and those certainly should be carried
out. We are looking forward eagerly to getting the results
of those to evaluate what potential effect, for example, as
I talked before, the location of the critical group might
make on that.
The last item on our agenda, for which we have
about five minutes, is myself. I would like to talk very
briefly about some selected topics from our priority issues.
I would like to talk about issues that -- some of
these issues fall somewhat peripherally within our framework
and have a lesser relationship to the main body of the work
that we carry out.
I would like to call your attention to the
comments regarding agreement states issues on page 5 and
page 6. I would like not to read them to you. I think we
can all read.
These are things that keep coming up in our
discussions, areas where we find that there is a lack of
evidence for a given problem and we continue to maintain
them on our list of potential topics for the future.
What I would like to talk about very briefly is
the expert judgment slide, slide number 7. Namely, I
believe and we are seeing evidence of this, that expert
judgment continues to play an important role in the
. 46
decisionmaking process. You heard Bill discuss the
probabilistic volcanic hazard assessment.
There are concerns within the probabilistic
volcanic hazard assessment that are perhaps broader than
simply that one assessment, mainly the question of
incorporation of new data. As Dr. Garrick has pointed out,
there are methodologies for handling the incorporation of
new data into an expert elicitation. Those are
methodologies that are available, they have been exercised
in the PVHA program. It is more difficult to incorporate a
paradigm shift conceptual model but, even there, there are
helps that may come from the PRA field with regard to that.
The point I would like to stress here is the
question of communications between the DOE and the NRC
staff. We have seen improvements in the communications
between those two entities but we believe there is a great
deal of improvement that still could be made.
Specifically, I personally find what I see is a
talking past each other phenomenon that is common with
younger persons in general.
[Laughter.]
COMMISSIONER ROGERS: Does that include us?
DR. POMEROY: No.
COMMISSIONER ROGERS: I thought that was a
technique that developed with age.
. 47
DR. POMEROY: I don't want to comment on the DOE's
half of this game but I do feel there is a need for the NRC
to evaluate elicitations that it does receive. I feel there
is a need to respond and to comment on any DOE initiatives
that are undertaken as a result of requests from the NRC. I
feel very strongly that there should be clear statements of
the criteria that are going to be used for closure of a
given issue and I have to say that, in spite of our working
group meeting and in spite of attending the technical
exchange, I would still need a statement of the "official"
NRC position. I am unable to determine that at this time.
CHAIRMAN JACKSON: The official NRC position on?
DR. POMEROY: On igneous activity, on the closure
of igneous activity, what their actual numbers are. These
are often presented by members of the center staff who, of
course, do not speak for the NRC staff and a clear statement
of the NRC position was one of the objectives that we had
for our working group session. We hope the improvement that
we have seen in communications will result in further
communication in the future.
CHAIRMAN JACKSON: Thank you.
DR. POMEROY: I believe that is all I would like
to say, except to say I hope you can discern out of what we
have presented here today two themes. One is that we
strongly support risk-informed performance-based regulation
. 48
and, secondly, that we support the use of scientific and
technical data to the maximum extent possible in formulating
all of our responses and regulations.
I think that is all we have.
CHAIRMAN JACKSON: Further questions?
COMMISSIONER ROGERS: Just on this expert judgment
topic which has, I think, always been an interesting and
challenging one as to how to use it, I wonder if you could
say anything more about the use of expert judgment in those
areas where there might be some kind of scientific
disagreements. It looks as if this has worked pretty well,
particularly in the igneous area, as far as I can learn. I
know you touched on the issue of human intrusion as not
being a scientific question and I am not introducing the
notion that expert judgment could help very much in that
one. I mean, I have set that one aside, I don't know.
But in other areas, it seems to me there is a
gradation from a lot of knowledge and a lot of data to a
little data and a lot of experience in some ways but not
necessarily that much data. And the issue of, is it
possible to collect more data to pin things down versus
coming to a decision that is probably very difficult to get
more data although, if one waited, you know, another hundred
years or so you could get more data.
I wonder if you have any thoughts as to how one
. 49
might structure the use of expert judgment in coming to -- I
hate to use the word "closure" because closure has certain
connotations here. But at least coming to a common
assessment that at this particular time nothing more in
required. Let's call it whatever you want to call it, but I
wouldn't call it closure because closure really seems to
connote that it really is a settled issue with NRC and
nothing is settled until everything gets looked at together,
you know, as we have said many times.
So I wonder if you have any thoughts on how to
perhaps adopt a little more structured approach to the use
of expert judgment that would help in somehow or other
deciding we have come to the point that nothing more is
required right now?
DR. POMEROY: Let me offer a few comments. I am
not sure I can answer that question completely but let me
say first there are, of course, as you are well aware, other
assessments or elicitations going on at the present time.
The probabilistic siting hazard assessment and a number of
assessments in association with the abstraction process of
TSPA and also simply an elicitation of experts in various
areas like the unsaturated zone hydrology.
In the unsaturated zone hydrology workshop, the
experts themselves were given the question. Do you see the
need for additional data and, if so, what additional data do
. 50
you see? They got some very positive responses that there
was a need for additional data and so that feedback occurred
within the expert elicitation process.
We have long discussed among ourselves the
question of how expert elicitation is going to be accepted
in the legal or adversarial, at least, environment that we
will eventually be functioning in and at one point we felt
very strongly and I think I personally still do that we
should attempt to try to formulate a rulemaking process, in
fact, that we feel at that point that guidance was not
sufficient.
There are questions, some legitimate questions
that the staff has raised with regard to PVHA that aren't
easily decidable in terms of how do you select experts, how
do you ensure that there is a full spread that the people
who are involved in the process can provide you the full
range of uncertainty in the given process that you are
looking at.
Some of those could be answered by a more
formalized structure for the use of expert judgment. I
believe that there are discussions within the NRC staff
itself as to the relative -- still, as to the relative value
of the expert judgment elicitation, formal elicitation
process. That is a good thing to have. But we need at some
point to reach some consensus on those in terms of moving
. 51
the process forward.
I think if you have looked at Dr. Brocoum's slides
from a recent management meeting, those are -- those
indicate clearly that there is a problem between what DOE
sees as the value of the expert judgment elicitations and
what he perceives as the NRC response to those questions.
I think there is still room for improvement here
and we need to work still with the various groups to see
whether we can't formulate some of that.
DR. GARRICK: I think I would like to make one
comment on the whole issue of expert judgment. One of the
things that I have observed as that as we work harder to
develop a schema for expert elicitation, it seems that one
of the fallouts of that is that we discover new ways of
finding information.
I am thinking, for example, of a non-NRC facility
where, in its early days of analysis, namely the Waste
Isolation Pilot Plant, there was heavy dependence upon
expert elicitation. And what happened was as the expert
elicitation took place and was highly criticized in most
cases, especially that having to do with future societies,
it did sharpen the wits and the creativity of the
investigators on how to find data to at least narrow the
issues that -- on which they would have to do expert
elicitations.
. 52
So it has had an interesting side effect of
sharpening up the ability to scope issues such that maybe
there is more information than one thought. You know, a
simple analogy would be if you are asked to analyze a first-
of-a-kind system for which there is no data, you don't know
quite where to start. But if, on the other hand, you start
looking at that system and breaking it apart and you find at
the subsystem and component level there is lots of
information, then it becomes a matter of how well you can
aggregate that into the total system and I think there is
some of that kind of benefit that has come from the expert
elicitation exercises.
CHAIRMAN JACKSON: Commissioner Dicus?
COMMISSIONER DICUS: No, thank you.
CHAIRMAN JACKSON: Commissioner McGaffigan?
COMMISSIONER McGAFFIGAN: I would like to go to a
slide that you skipped past under B.1, number 6, on
decommissioning nonreactor facilities. I want to precede
this by thanking you for the letter that you sent last month
with regard to the decommissioning rule and the
appropriateness of the 25 millirem per year all pathways
standard that is proposed by the staff and not having a
separate groundwater standard.
But this first bullet on that page, the notion
that we as a government may need to think about getting all
. 53
of this waste activity into a single home is one that I
haven't seen before but, given what I know now, it rings
true to me. NORM, the NORM issue which you cite in your
parentheses there, there are lots of NORM sites around this
country that are at least as dirty as anything that we are
going to try to clean up under the rule that you commented
on last month. Yet they are unregulated at the moment,
effectively. We argue about what NORM is and
technologically enhanced NORM and the various fossil
industries come in and say, you know, not us. And we even
have a letter on record from the American Petroleum
Institute saying, you know, please don't ever apply that
standard to us, the 25 millirem per year all pathways.
Have you gone any further? Is there anything
behind this bullet other than a plea for rationality?
DR. POMEROY: The simple answer to that is, not a
great deal. It is a statement of rationality that we came
to in the process of looking at the low-level waste program
which we responded to earlier.
When we began to look at that in an examination of
many of the other activities that we have looked at in the
past, one comes to the immediate conclusion that there needs
to be a rational order placed on this and it seems
intuitively obvious to us, perhaps, that such a thing should
happen, that the NRC should be responsible for all
. 54
radiological wastes and that there should be a single entity
governing that.
COMMISSIONER McGAFFIGAN: But that would require
an amendment to the Atomic Energy Act.
DR. POMEROY: That's certainly true. We recognize
that.
[Laughter.]
DR. POMEROY: The laugher means that's impossible?
CHAIRMAN JACKSON: No, no. A private joke here.
On behalf of the Commission let me thank you and
commend you for a very high-quality briefing. The
committee's deliberations and advice will be of tremendous
benefit to us as we grapple with the issues particularly
related to licensing of a high-level waste repository. So
the Commission greatly appreciates all of your efforts in
those areas as well as the others and that was a
particularly nice walk through from the perspective of the
committee's views on risk-informed performance-based
regulation, which is always a favorite topic.
So, unless there are further comments, we are
adjourned.
[Whereupon, at 3:32 p.m., the meeting was
adjourned.]
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