Copyright 2000 Federal News Service, Inc.
Federal News Service
June 23, 2000, Friday
SECTION: PREPARED TESTIMONY
LENGTH: 3018 words
HEADLINE:
PREPARED TESTIMONY OF KEVIN D. CROWLEY, PH.D. DIRECTOR BOARD ON RADIOACTIVE
WASTE MANAGEMENT NATIONAL RESEARCH COUNCIL
BEFORE THE
HOUSE COMMITTEE ON COMMERCE SUBCOMMITTEE ON ENERGY AND POWER
SUBJECT - YUCCA MOUNTAIN RADIATION PROTECTION
STANDARDS
BODY:
Chairman Barton and
subcommittee members, thank you for the opportunity to appear before the Energy
and Power Subcommittee to testify on the Environmental Protection Agency's
(EPA's) draft radiation protection standards for Yucca
Mountain. I am the director of the National Research Council's Board on
Radioactive Waste Management (BRWM), which was established by the National
Academy of Sciences (NAS) in 1958 to provide scientific and technical advice to
the federal government on the safe and responsible management of radioactive
waste. My testimony to the subcommittee today will focus on recent reports from
the BRWM and committees under its oversight that bear directly on the question
of radiation protection standards for Yucca Mountain. In
particular, I will discuss the findings and recommendations from two reports:
Technical Bases for Yucca Mountain Standards, also known as the
"TYMS report," which was published in 1995, and a 1999 BRWM report entitled
Comments on Proposed Radiation Protection Standards for Yucca
Mountain, Nevada by the Board on Radioactive Waste Management.
As you know Mr. Chairman, the Energy Policy Act of 1992 directed EPA to
promulgate radiation protection standards specifically for a potential
repository at Yucca Mountain, Nevada. The Act directed the EPA
Administrator to obtain advice from the NAS on the technical bases for radiation
protection standards, and the Act further mandated that EPA base its standards
on the NAS recommendations. To respond to this request, the National Research
Council, the operating arm of the NAS and National Academy of Engineering,
appointed a BRWM committee in early 1993 to provide advice to EPA on the
standards. The committee held a series of information-gathering and deliberation
meetings (many in Nevada) over a period of about two years and issued its
recommendations in the 1995 TYMS report.
In developing its
recommendations, the TYMS committee was very careful to distinguish between
scientific and policy judgments. The committee recognized that some elements of
the standards could be addressed using scientific data and understanding,
whereas other elements required societal value judgements. For example, the
committee recognized that there is no basis in science for establishing
acceptable radiation exposure limits but, rather, "acceptability" was a societal
value judgement that was best established through the rulemaking process.
Similarly, the TYMS committee noted that the time period of applicability of the
standards has both scientific and policy aspects.
EPA published its
draft radiation protection standards in the Federal Register (64 FR 46976-47016)
on August 27, 1999. The BRWM, acting under its own initiative and with approval
of the National Research Council's governing board, decided to issue a report
that compared the draft EPA standards with the recommendations in the TYMS
report. The purpose of this comparison was to determine whether EPA followed the
recommendations laid out in the TYMS report and, if not, to suggest how EPA
could modify its draft standards to make them consistent. The BRWM's report was
submitted to the public docket during the comment period for EPA's draft
standards. This report reflected the consensus of the BRWM and was approved for
release by the National Research Council after being subjected to the Research
Council's review process.
The BRWM found that EPA's draft standards were
consistent with the 1995 TYMS report in several important aspects, the most
significant of which are the following: Who is Protected. The TYMS report
recommended that the radiation protection standard be applied to representative
individuals who have the highest risk from radiation releases from the
repository. EPA proposed a standard to protect individuals living near the
repository--using a reasonably maximally exposed individual (RMEI)--- that is
broadly consistent with the TYMS report's recommendation. Level of Protection.
The TYMS report concluded that the numerical value for the radiation protection
standard was a policy decision to be established through the rulemaking process.
EPA has used rulemaking to establish an "allpathways" standard. This standard
sets an upper limit on the exposure the RMEI can receive from radiation releases
through all potential release pathways, including groundwater and the
atmosphere. The numerical value of this standard proposed by EPA falls within
the range of values suggested in the TYMS report. Human Intrusion. EPA follows
the TYMS report's recommendations that the standards should require active and
passive institutional controls to prevent human intrusion into the repository in
the near term; that the standard should be based on explicitly defined
assumptions about how human intrusion could occur in the long term; and that the
standard should set limits on radiation exposure to individuals as a result of a
human intrusion that are no more stringent than the all- pathways standard.
Exposure Scenarios. The TYMS report concluded that there is no scientific basis
for predicting future scenarios by which humans could be exposed to radiation
from a Yucca Mountain repository. Therefore, the report
recommended that such scenarios be established through the rulemaking process.
EPA has used rulemaking to define exposure scenarios based on the state of
society, human biology, and knowledge that exists at the time of submission of
the license application for the repository.
There are also several
elements of EPA's proposed standards that are inconsistent with the
recommendations in the TYMS report. My testimony will focus on the three most
important elements: risk- versus dose-based standards; the inclusion of a
separate groundwater standard; and the time period over which the standard
should be applied.
Risk-Versus Dose-Based Standards
EPA proposes
a standard that is based on the dose an individual may receive as a result of
radioactive releases from the repository. The TYMS report specifically
recommended against basing the standard on dose. Instead, the report recommended
that the standard be based on the risk to individuals of an adverse health
effect from radiation releases, and the report further recommended that
rulemaking be used to establish an acceptable risk level.
The TYMS
committee recommended a risk-based standard for several reasons. First, the
committee recognized that a risk-based standard is more understandable to the
public than a dose-based standard and its use would therefore promote more
meaningful public involvement in what truly is a public policy decision. A
risk-based standard can be expressed as a simple probability of developing a
fatal cancer--for example, a standard that has a numerical annual risk value of
10-4 would mean that an individual living near the repository could have no
greater than a 1 in 10,000 chance per year of developing a fatal cancer from
radiation releases from the repository.
A dose-based standard, in
contrast, provides no indication of hazard levels and is understandable only by
experts. The proposed EPA all- pathways dose standard of 15 millirems per year,
for example, provides no indication of the number of fatal cancers that could be
expected in a given year from repository releases.
Second, a risk-based
standard for Yucca Mountain can be compared directly to other
risk-based standards, such as EPA's standards for toxic chemicals, because they
use common units of measurement. Also, the magnitude of the risk value
corresponds directly to the level of hazard. For example, a 10'5 (1 chance in
100,000) risk standard for Yucca Mountain would provide the
same level of public protection as a 10'5 risk standard for regulating a
particular toxic material, assuming of course that both standards were based on
the same health effect such as fatal cancers. EPA currently regulates hazardous
chemicals on the basis of risk, so the adoption of a risk-based radiation
protection standard for Yucca Mountain would promote uniformity
across EPA's family of regulations.
Third, a risk-based standard would
not have to be revised by subsequent rulemaking as advances in scientific
knowledge improve our understanding of radiation effects on human health. There
have been significant improvements in our understanding of radiation effects on
human health over the past few decades, and dose-based standards have had to be
adjusted as our knowledge has improved. There is reason to believe that these
improvements will continue and that adjustments to dose-based standards will be
necessary in the future. For a risk-based standard, the level of acceptable risk
would be established during initial rulemaking. This level would not have to be
changed if new science indicated a change in the relationship between dose and
health effects.
EPA's use of a dose-based standard not only makes it
difficult for the public to provide meaningful input to the rulemaking process,
but it may also lower public confidence in the output from that process. Take,
for example, the disagreement between the EPA and U.S. Nuclear Regulatory
Commission (USNRC) over radiological criteria for unrestricted use of nuclear
sites. The EPA standard (based on 40 CFR Part 191) is 15 millirems per year,
whereas the USNRC regulation (10 CFR 20.1402) is 25 millirems per year with
ALARA (as low as reasonably achievable). Both agencies claim that their release
limits are protective of public health. What is the public to think when the two
federal agencies charged with protecting public health cannot agree on what the
protective limits should be? The reason the EPA's and USNRC's limits are
different is that each agency has a different starting point for establishing
the exposure limit values, and neither agency uses risk to establish such
limits.
EPA points out in the preamble to its draft standards that it
was directed by the Energy Policy Act to develop a "dose-based standard." The
TYMS report's recommendation that the form of the individual- protection
standard be based on risk does not preclude EPA from expressing the numeric
value of the standard in units of risk and in derivative units of dose, so long
as the risk value is clearly understood as the underlying basis for the proposed
dose standard. In its 1999 report, the BRWM noted that such an approach "would
achieve the aims of the TYMS report's recommendations and it would allow EPA to
meet its Congressional mandate."
To summarize, the use of a risk-based
standard in the Yucca Mountain rule would have several
benefits: there would be clear traceability between the numerical value of the
standard and the public policy decision on what is an acceptable risk;- the
standard would be more readily understood by nonexperts, which could help
promote more meaningful public input to rulemaking and greater public confidence
in the resulting regulations; this approach would facilitate uniformity of the
standard with regulations for other hazards such as toxic chemicals; and if a
risk-based approach were implemented for all elements of the Yucca
Mountain standard, it would eliminate the current problem with the
groundwater element of the standard, which I will discuss next.
The 1999
BRWM report noted that a risk-based standard would be more difficult to
implement than a dose-based standard, and that EPA might find it far more
difficult to ask the public about acceptable risk levels than to follow
established precedents. Nevertheless, a risk- based standard was recommended
both in the TYMS report and the 1999 BRWM report because it requires public
involvement in what is fundamentally a public-policy decision.
Inclusion
of a Separate Groundwater Standard,
EPA has included a standard for the
protection of groundwater in its proposed rule in addition to the all-pathways
standard described previously. The proposed groundwater standard appears to be
designed to protect both individuals living near the repository and the general
public living at some distance from the repository. The groundwater standard is
a holdover from EPA's 1985 disposal regulations (40 CFR Part 191) and is taken
directly from the EPA's safe drinking water regulations (40 CFR Part 141).
In incorporating the groundwater standard into the Yucca
Mountain standards, EPA has made several modifications from the safe
drinking water regulations. First, the groundwater standard in EPA's safe
drinking water regulations applies to public water systems. For the
Yucca Mountain standards, EPA proposes to apply the groundwater
standard to a groundwater aquifer some 2,000 feet below the Earth's surface at
the Yucca Mountain site and at some as yet undetermined
distance from the repository boundary--the point of compliance for alternatives
being proposed by EPA range from 5 to 30 kilometers (3 to 19 miles) from the
repository boundary. The Yucca Mountain standard also applies
to a volume of groundwater in the aquifer rather than to water delivered by a
public water system--EPA has proposed a value of 1,285 acre-feet (about 420
million gallons) but has also asked for comments on values that range from 10 to
4,000 acre feet (3 million to 1.3 billion gallons). The numerical value of the
standard itself is based on 40-year-old dosimetry and does not conform with
current international standards, and it represents a different level of risk
than the all-pathways standard of 15 millirems per year.
The TYMS
committee recognized that groundwater is likely to be the primary source of
individual exposure to radioactive materials that escape from Yucca
Mountain, and that committee found that the all- pathways standard
would protect both local and distant populations. Therefore, the TYMS committee
did not recommend a separate groundwater standard. The 1999 BRWM report
concluded that the imposition of a separate groundwater standard "may greatly
complicate the licensing process (for Yucca Mountain) and have
but a negligible impact on protection of the public."
The 1999 BRWM
report concluded that there was no basis in science for establishing a separate
groundwater standard and recommended that EPA either "make more cogent
scientific arguments to justify the need for this standard," or if it wishes to
establish a separate standard as a matter of policy, that it "explicitly state
the policy decisions embedded in the proposed standard and ask the public to
comment on those decisions." The 1999 BRWM report did not suggest what
scientific arguments EPA could use to justify a separate groundwater standard,
but I would like to close this part of my testimony by suggesting one possible
approach for resolving the BRWM's objections.
I believe that EPA could
justify a separate groundwater standard by adopting the risk-based approach
recommended in the TYMS report. If EPA based its Yucca Mountain
standards on a SINGLE VALUE OF ACCEPTABLE RISK, it could express that risk in
terms of two elements, one for radiation exposures through the groundwater
pathway (a groundwater standard) and one for exposures through all pathways (an
all-pathways standard). These two elements would be scientifically consistent so
long as they are based on a single value of acceptable risk. To implement this
approach, EPA would have to modify the dose values for the all-pathways and
groundwater elements that currently exist in its proposed rule so that they
represent the same value of acceptable risk.
Time Period Over Which the
Standard Should be Applied
EPA proposes that the radiation protection
standards at Yucca Mountain be applied over a time period of
10,000 years. The TYMS report concluded that (1) an arbitrary time limit such as
10,000 years has no scientific basis, and (2) peak risks from radiation releases
from the repository are likely to occur beyond 10,000 years. The report
recommended compliance be assessed for the site's period of geologic stability
and noted that a technical assessment of the site should be feasible for on the
order of one million years. After the TYMS report was published, EPA asked for
public comment on the timescale issue, and the majority of those commenting
stated that compliance should be assessed at the time of peak risk.
EPA
has nevertheless retained its earlier recommendation for quantitative compliance
assessment only up to 10,000 years and has given a series of policy and
technical arguments for this choice. The TYMS report excluded policy
considerations from its deliberations on this issue, but concluded, as noted
previously, that "there is no scientific basis for limiting the time period to
... 10,000 years. Clearly, the 10,000-year limit is strictly a policy choice and
should be acknowledged as such" by EPA. As the proposed standards currently
read, the policy origin of the limit is not evident.
Though compliance
is assessed for a period of 10,000 years, EPA requires that the repository
performance be examined past this point "to see if dramatic changes ... could be
anticipated" (64 FR, p. 46993). Here EPA provides no guidance as to what
qualifies as a dramatic change or as to the purpose of the examination. The BRWM
believes that this aspect of the standard will provide "no real benefits to
protection of the public." The BRWM noted that EPA "may wish to be more specific
in providing guidance on how the analyses beyond 10,000 years could be used in
determining compliance" or explicitly pass this task to the USNRC.
In
conclusion Mr. Chairman, a Yucca Mountain repository must
isolate waste from the environment for many millennia. It is essential that the
standard for this repository reflect the best thinking that science has to
offer. The overall conclusion of the 1999 BRWM report is that the current EPA
draft standards fall short of this goal in some important respects. The BRWM
hopes that EPA will accept the suggestions it has made for improvements in the
proposed standards.
This concludes my testimony to the committee. I
would be happy to clarify my comments or answer committee members' questions.
Again, thank you for the opportunity to testify.
END
LOAD-DATE: June 27, 2000 
