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OCR for page 166
10
Findings and Recommendations
The U.S. Nuclear Regulatory Commission's (USNRC's) regulations on pro-
tection against radiation, 10 CFR Part 20, do not contain predetermined concen-
trations, amounts, or quantities of radionuclides in solid materials below which
these materials can be released from further regulatory control. Solid materials
potentially available for release from regulatory control include metals, building
concrete, on-site soils, equipment, and furniture used in routine operation of
licensed nuclear facilities. Most of this material will have no radioactive contami-
nation, but some of it may have surface or volume contamination. Licensees
continue to request permission from the USNRC and agreement states to release
such solid materials when the materials are no longer useful, pursuant to Section
2002 of 10 CFR Part 20 or compatible state regulations, or when the licensed
facility is decommissioned. The USNRC does use a guidance document issued
by the Atomic Energy Commission in 1974, Regulatory Guide 1.86, which con-
tains limits applicable to surface contamination and allows clearance of solid
materials, usually by incorporation into license technical specifications.
The USNRC allows licensees to release solid material according to preestab-
lished criteria. For reactors, if surveys for surface residual radioactivity per-
formed by the licensee on equipment or materials indicate the presence of radio-
activity above natural background levels then release is not permissible.] If no
such surface activity is detected, then the solid material in question need not be
treated as waste under 10 CFR Part 20. This approach sometimes leads to prob-
1Reactor licensees can apply to USNRC for approval for clearance of solid materials with small
but detectable levels of radioactivity pursuant to Section 2002 of 10 CFR Part 20 on a case-by-case
basis.
166
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FINDINGS AND RECOMMENDATIONS
167
lems when detectors of greater sensitivity than were used in the initial survey
detect radioactivity above the threshold in previously released material (USNRC,
2001b). For surface-contaminated solid materials possessed by a materials lic-
ensee, the USNRC usually authorizes the release through specific license condi-
tions (USNRC, 2001b). In the case of volume-contaminated materials held by
reactor and materials licensees, the USNRC has not provided guidance similar to
that found in Regulatory Guide 1.86 for surface contamination. These situations
are instead decided on an individual basis by evaluating the doses likely to be
associated with the proposed disposition of the material.
The USNRC has attempted to update and formalize its policies on disposi-
tion of slightly radioactive solid material (SRSM). In 1990, the USNRC issued a
policy as directed by the Low Level Radioactive Waste Policy Amendments Act
of 1985 (LLWPAA) that declared materials with low concentrations of radioac-
tivity contamination to be "below regulatory concern" (BRC) and hence deregu-
lated (55 Federal Register 27522; July 3, 1990~. However, Congress intervened
to set aside the BRC policy in the Energy Policy Act of 1992 after the USNRC's
own suspension of the policy (56 Federal Register 36068; July 30, 1991~. In
1999, the USNRC again examined the issue of disposition of SRSM and pub-
lished a Federal Register notice examining several policy options (64 Federal
Register 35090-35100; June 30, 1999~. In neither case was the USNRC able to
convince consumer and environmental groups that clearance of SRSM could be
done safely or to convince some industry groups that clearance is desirable.
In August 2000, the USNRC asked the National Research Council to form a
committee to provide advice in a written report. The committee addresses its
tasks in Chapters 2 through 9 of the report, each of which contains a set of
findings, a subset of which is presented. The reader is encouraged to review all of
the findings as well as the supporting documentation in each chapter. The major
findings and recommendations follow.
MAJOR FINDINGS
Regulatory Framework (Chapter 2)
Finding 2.1. The USNRC does not have a clear, overarching policy statement for
management and disposition of SRSM. However, SRSM has been released from
licensed facilities into general commerce or landfill disposal for many years
pursuant to existing guidelines (e.g., Regulatory Guide 1.86) and/or following
case-by-case reviews. The USNRC advised the committee of no database for
these releases.
Finding 2.2. A dose-based clearance standard can be linked to the estimated risk
to an individual in a critical group from the release of SRSM. The general regu-
latory trend is toward standards that are explicitly grounded in estimating risks.
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168
THE DISPOSITION DILEMMA
Finding 2.3. For clearance of surface-contaminated solid materials, the clearance
practices regulated by the USNRC and agreement states are based on the guid-
ance document Regulatory Guide 1.86, which is technology based and has been
used satisfactorily in the absence of a complete standard since 1974.
Finding 2.4. For clearance of volume-contaminated solid materials, the USNRC
has no specific standards in guidance or regulations. Volume-contaminated SRSM
is evaluated for clearance on a case-by-case basis. This case-by-case approach is
flexible, but it is limited by outdated, incomplete guidance, which may lead to
determinations that are inconsistent.
Finding 2.5. Industrial activities are generating very large quantities of techno-
logically enhanced naturally occurring materials (TENORM). Federal regulation
of TENORM has been largely absent. State regulations vary in breadth and depth.
Anticipated Inventories of Radioactive or Contaminated Materials
(Chapter 3)
Finding 3.1. Licensees may seek to clear about 740,000 metric tons of metallic
SRSM that arise from decommissioning the current population of U.S. power
reactors during the period 2006 to 2030 (about 30,000 to 42,000 metric tons per
year). About 8,500 metric tons per year are expected to arise from decommission-
ing USNRC-licensed facilities other than power reactors during the same time
period. The total quantity of metal from both power reactor and non-power reac-
tor licensees, up to approximately 50,000 metric tons per year, represents about
0.1 percent of the total obsolete steel scrap that might be recycled during that
same 25-year period.
Finding 3.2. If most of the licensees of currently operating reactors obtain 20-
year license extensions, relatively little SRSM will arise from power plant de-
commissioning during the 2006-2030 period.
Finding 3.3. Because of the difficulty of determining the quantities and levels of
contamination that have penetrated into the concrete, concrete SRSM is generally
considered to be volume contaminated. Concrete SRSM constitutes more than 90
percent of the total SRSM arising from decommissioning the population of U.S.
power reactors.
Pathways and Estimated Costs for Disposition of Slightly Radioactive
Solid Materials (Chapter 4)
Finding 4.1. Disposal of all slightly radioactive solid materials arising from
decommissioning the population of U.S. power reactors into low-level radioac-
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FINDINGS AND RECOMMENDATIONS
169
five waste disposal sites would be expensive (about $4.5 billion to $11.7 billion)
at current disposal charge rates. Disposal in Subtitle D or Subtitle C landfills
would be cheaper ($0.3 billion to $1 billion, respectively). Clearance of all of this
material could reduce disposal costs to nearly zero (assumes 100 percent reuse or
recycle) or might even result in some income (~$20 million) arising from the sale
of scrap materials for recycle or reuse. Decontamination, segmentation, and trans-
port costs are not included in the costs estimated in this report for disposition.
Review of Methodology for Dose Analysis (Chapter 5)
Finding 5.1. Analytical work in the United States and abroad over the past two
decades is useful in understanding the likely doses associated with exposure
scenarios that might occur under various clearance standards. Much of the techni-
cal analysis in this field has the objective of understanding "dose factors," which
to date have been analyzed in depth only for (unconditional) clearance scenarios.
A dose factor is used to convert a concentration of radioactivity that is about to be
released, whether it be confined to a surface or contained within a volume, to a
primary dose level (measured in microsieverts per year or millirems per year).
With such a dose factor in hand, a primary dose standard can be converted to
obtain a secondary clearance standard in terms of radionuclide activity, which
could then be used at USNRC-licensed facilities. A dose factor can be used with
any choice of primary dose standard.
Finding 5.2. Selecting a primary dose standard is a policy choice, albeit one
informed by scientific estimates of the health risk associated with various doses.
For instance, as shown in Table 1-2, a lifetime dose rate of 10 ,uSv/yr (1 mrem/yr)
equates to an estimated increased lifetime cancer risk of 5 x 10-5, which falls
within the range of acceptable lifetime risks of 5 x 10= to 10-6 used in developing
health-based radiation standards other than radon in the United States (NRC,
1995, p. 50~. When setting primary dose standards, regulators can make a policy
decision to include a level of conservatism such that the final standard is in excess
of the best-estimate dose factor and in this way account for uncertainty (e.g.,
selecting the 90th, 95th, or other percentile in the distribution for the dose factor,
instead of the best-estimate value).
Finding 5.3. The uncertainty in dose factor estimates is a key technical issue.
When an uncertainty has been estimated, a quantitative determination can be
made of the likelihood that the dose to an individual in the critical group will be
below the primary dose standard. Quantitative uncertainty estimates can also
assist regulators in assigning a level of conservatism to dose factors in excess of
the best estimate. Dose factors developed by analysts from different countries
show wide variation, which highlights the need for careful consideration of un-
certainties.
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170
THE DISPOSITION DILEMMA
Finding 5.4. The committee concludes from its review that of the various reports,
draft NUREG-1640 (USNRC,1998b) provides a conceptualframework that best
represents the current state of the art in risk assessment, particularly with regard
to its incorporation of formal uncertainty, as judged using recommendations of
this committee and other committees of the National Research Council. Once the
limitations in draft NUREG-1640 have been resolved (see Findings 5.5 and 5.6
[see Chapter 51) and the results are used in conjunction with appropriate dose-risk
estimates in the final version of the report or in follow-up reports the USNRC
will have a sound basis for considering the risks associated with any proposed
clearance standards and for assessing the uncertainty attached to these dose esti-
mates.
Finding 5.7. The dose factors developed in draft NUREG-1640 should not be
used to derive clearance standards for categories of SRSM other than those con-
sidered in the draft NUREG-1640, without first assessing the appropriateness of
the underlying scenarios. Some of the dose factors developed in draft NUREG-
1640 are likely to require modification when applied to other mixtures of radio-
nuclides (e.g., mixtures in which transuranics dominate) and other clearance
scenarios, such as may be relevant to DOE material and technologically en-
hanced naturally occurring radioactive material (TENORM).
Measurement Issues (Chapter 6)
Finding 6.3. For a 1 mrem/yr or higher standard (and the corresponding derived
secondary screening levels), the majority of radionuclides can be detected at
reasonable costs in a laboratory setting, under most practical conditions. For a 0.1
mrem/yr standard, the measurement capability falls below the upper bound of
minimum detectable concentrations for some radionuclides in some laboratories,
although 85 percent of radionuclides are still detectable. Using field measure-
ments, a more rapid fall-off of detectability is observed at more stringent radia-
tion protection levels, with 31 of 40 key radionuclides detectable at 1 mrem/yr
and 11 of 40 detectable at 0.1 mrem/yr.
International Approaches to Clearance (Chapter 7)
Finding 7.1. The EU and the IAEA have each established a dose-based standard
of 10 ,uSv/yr (1 mrem/yr) for the clearance of materials from regulatory control.
A collective dose standard is also included, expressed as a committed dose equiva-
lent of 1 man-Sv per year of exposure of the affected group (100 man-rem total
effective dose equivalent per year).2
2Provisions exist in the EU safety directives for competent authorities in member states to develop
alternative clearance guidance for special or specific circumstances.
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FINDINGS AND RECOMMENDATIONS
171
Finding 7.3. A body of science, policy, and literature supports the development
of the EU safety directives related to radioactive solid material clearance. In
particular, the IAEA has developed policy guidance found in Principles for the
Exemption of Radiation Sources and Practices from Regulatory Control (IAEA,
1988).
Stakeholder Reactions and Involvement (Chapter 8)
Finding 8.1. The USNRC involved stakeholders in the processes for the BRC
policy and the License Termination Rule for decommissioning, as well as in the
initial stages of considering standards for release of SRSM. Despite these efforts,
environmental and consumer advocacy groups remain concerned with radiation
effects, and industrial groups continue to be concerned with the potential eco-
nomic consequences of the clearance of SRSM.
Finding 8.3. Stakeholder groups differed in their viewpoints on regulating dispo-
sition of SRSM. Generally, professional societies associated with the nuclear
industry supported clearance, industrial groups endorsed conditional clearance,
and environmental groups opposed any type of clearance. However, much of the
opposition to a clearance standard was associated with recycling metal SRSM
into general commerce.
Finding 8.4. A legacy of distrust of the USNRC has developed among most of
the environmental stakeholder groups. This distrust results from their experience
with the BRC policy, the License Termination Rule, and the 1999 issues paper on
the release of SRSM. Reestablishing trust will require concerted and sustained
effort by the USNRC, premised on a belief that stakeholder involvement will be
important and worthwhile, as well as a prerequisite for making progress.
Framework and Process for Decision Making (Chapter 9)
Finding 9.1. The committee found no evidence that the problems with the current
approach to clearance decisions require its immediate replacement. The commit-
tee concludes that there is sufficient time to conduct a thorough and systematic
analysis and evaluation, including a sound process of stakeholder participation
and involvement, of alternative approaches to the disposal of SRSM.
RECOMMENDATIONS
In developing its recommendations the committee was guided by two
overarching, compelling findings:
1. The current approach to clearance decisions is workable and is suffi-
ciently protective of public health that it does not need immediate re-
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72
THE DISPOSITION DILEMMA
vamping. However, the current approach, among other shortcomings, is
inconsistently applied, is not explicitly risk based, and has no specific
standards in guidance or regulations for clearance of volume-contami-
nated slightly radioactive solid material. Therefore, the committee be-
lieves that the USNRC should move ahead without delay and start a
process of evaluating alternatives to the current system and its shortcom-
ings.
2. Broad stakeholder involvement and participation in the USNRC's deci-
sion-making process on the range of alternative approaches is critical as
the USNRC moves forward. The likelihood of acceptance of a USNRC
decision greatly increases when the process (1) engages all responsible
stakeholder representatives and viewpoints, (2) is perceived by partici-
pants as fair and open, (3) addresses all the advantages and disadvantages
of the alternative approaches in an even-handed way, and (4) is open to a
broad and creative range of alternatives. Thus, it is essential that the
USNRC focus on the process and not prescribe an outcome. The outcome,
an approach to disposition of slightly radioactive solid material, must
evolve from the process.
While the committee did not want to prescribe the outcome of the decision
process, it has made several specific recommendations, conditional on the pro-
cess arriving at certain decision points. For example, if the USNRC contemplates
clearance or conditional clearance standards, the committee recommends that
these standards be dose based. The committee also recognized that significant
national and international efforts have been completed, or are near completion,
that provide a solid foundation for the USNRC to move forward. The committee
has recommended the foundation from which to begin the process. Thus, the
USNRC should be able to proceed expeditiously with a broad-based stakeholder
participatory decision making process.
Recommendation 1. The USNRC should devise a new decision framework that
would develop, analyze, and evaluate a broader range of alternative approaches
to the disposition of slightly radioactive solid material. At a minimum, these
alternatives should include the current case-by-case approach, clearance, condi-
tional clearance, and no release.
Recommendation 2. The USNRC's decision-making process on the range of
alternative approaches to the disposition of slightly radioactive solid material
should be integrated with a broad-based stakeholder participatory decision-mak-
ing process. Elements of this process should include the following:
.
The willingness and commitment of the USNRC to establish and main-
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FINDINGS AND RECOMMENDATIONS
173
lain a meaningful and open dialogue with a wide range of stakeholders regarding
the disposition of slightly radioactive solid material;
· An ad hoc broad-based advisory board that would advise the USNRC in
its consideration of approaches to the disposition of slightly radioactive solid
material. The advisory board would also suggest additional stakeholder involve-
ment mechanisms that the USNRC could use in the decision process (for ex-
ample, establishing a National Environmental Policy Act process; alternative
dispute resolution; and partnering, arbitration, mediation, or a combination of
such methods); and
.
Assistance obtained by the USNRC as needed from outside experts in
order to (1) assist its efforts to establish the ad hoc stakeholder advisory board
and to facilitate dialogue among the USNRC and stakeholder participants in the
decision-making process and (2) assess, evaluate, and perhaps conduct portions
of the USNRC stakeholder involvement program and make recommendations as
appropriate.
Recommendation 3. The USNRC should adopt an overarching policy statement
describing the principles governing the management and disposition of slightly
radioactive solid material. A review and discussion of the IAEA policy statement
Principles for the Exemption of Radiation Sources and Practices from Regula-
tory Control (Safety Series No. 89, IAEA Safety Guidelines, Vienna, 1988) with
a broad-based stakeholder group would provide a good starting point in develop-
ing a policy statement that would provide a foundation for evaluation of alterna-
tive approaches to disposition of slightly radioactive solid material.
Recommendation 4. When considering either clearance or conditional clear-
ance, a dose-based standard should be employed as the primary standard. To
employ a dose-based standard, it is necessary to consider a wide range of sce-
narios that encompass the people likely to be exposed to slightly radioactive solid
material. From these people, a critical group is selected and secondary standards
(based on dose factors) are derived. These secondary standards are used to limit
the radioactivity in materials being considered for release or conditional release.
The USNRC should also consider the pros and cons of the establishment of
a separate collective dose standard.
Recommendation 5. An individual dose standard of 10 ,uSv/yr (1 mrem/yr)
provides a reasonable starting point for the process of considering options for a
dose-based standard for clearance or conditional clearance of slightly radioactive
solid material. This starting point is appropriate for the following reasons:
· A dose of 10 ,uSv/yr (1 mrem/yr) is a small fraction (less than 0.5
percent) of the radiation received per year from natural background sources.
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THE DISPOSITION DILEMMA
· A dose of 10 ,uSv/yr (1 mrem/yr) is significantly less than the amount of
radiation that we receive from our own body due to radioactive potassium (one
contributor to background radiation) and other elements and to routine medical
procedures that involve ionizing radiation.
· A dose of 10 ,uSv/yr (1 mrem/yr) over a 70-year lifetime equates to an
estimated increase of 3.5 x 1 o-5 in the lifetime cancer risk, which falls within the
range of acceptable lifetime risks of 5 x 10= to 10-6 used in developing health-
based standards for exposure to radiation (other than for radon) in the United
States.
· Radiation measurement technologies are available at a reasonable cost
to detect radioactivity at concentrations derived from this dose standard.
.
This dose standard is widely accepted by recognized national and inter-
national organizations.
The final selection of an individual dose standard should nonetheless be a policy
choice, albeit one informed by the above considerations.
Recommendation 6. For any dose-based alternative approach to disposition of
slightly radioactive solid materials, the USNRC should use the conceptualframe-
work of draft NUREG-1640 to assess dose implications. To use the actual results
of NUREG-1640 in the decision framework discussed in Recommendations 1
and 2, the USNRC must first establish confidence in the numerical values, ex-
pand the scope of applicability, and overcome certain limitations in draft NUREG-
1640. At a minimum, the following specific actions are required:
.
Review the choice of parameter distributions used in the dose modeling,
as well as the characteristic values chosen for each parameter distribution.
.
options.
.
Develop complete scenarios and dose factors for conditional clearance
Provide sufficient information to enable calculation of collective doses
to support Recommendation 4.
.
Expand the current set of scenarios used to compute dose factors to
include (1) human error and (2) multiple exposure pathways.
The USNRC should use an independent group of experts to provide peer review
of these activities.
Recommendation 7. The USNRC should continue to review, assess, and partici-
pate in the ongoing international effort to manage the disposition of slightly
radioactive solid material. The USNRC should also develop a rationale for con-
sistency between secondary dose standards that may be adopted by the United
States and other countries. However, the USNRC should ensure that the technical
basis for secondary dose standards is not adjusted for consistency unless these
adjustments are supported by scientific evidence.
Representative terms from entire chapter:
solid material
