Generic Environmental Impact Statement for License Renewal of Nuclear Plants (NUREG-1437 Vol. 1, Part 1)
1.1 Purpose of the GEIS
This Generic Environmental Impact Statement (GEIS) for license renewal of nuclear plants was undertaken to assess what is known about the environmental impacts that could be associated with license renewal and an additional 20 years of operation of individual plants. That assessment is summarized in this GEIS. This GEIS provides the technical basis for an amendment to the Commission's regulations, 10 CFR Part 51, Environmental Protection Regulations for Domestic Licensing and Related Regulatory Functions, with regard to the renewal of nuclear power plant operating licenses. The rule amendment and this document were initiated with the objective that the efficiency of the license renewal process be improved by documenting in this GEIS and codifying in the Commission's regulations the environmental impacts that are well understood. Thus, repetitive reviews of those impacts may be avoided. The Commission's decision to undertake a generic assessment of the environmental impacts associated with the renewal of a nuclear power plant operating license was motivated by its belief in the following:
|(1)||License renewal will involve nuclear power plants for which the environmental impacts of operation are well understood as a result of data evaluated from operating experience to date.|
|(2)||Activities associated with license renewal are expected to be within this range of operating experience, thus environmental impacts can be reasonably predicted.|
|(3)||Changes in the environment around nuclear power plants are gradual and predictable with respect to characteristics important to environmental impact analyses.|
1.2 Renewal of a Plant Operating License--the Proposed Federal Action
Under NRC's environmental protection regulations in 10 CFR Part 51, renewal of a nuclear power plant operating license is identified as a major federal action significantly affecting the quality of the human environment, and thus an environmental impact statement (EIS) is required for a plant license renewal review. The EIS requirements for a plant-specific license renewal review are specified in 10 CFR Part 51. NRC's public health and safety requirements that must be met for the renewal of operating licenses for nuclear power plants are found in 10 CFR Part 54. Operating licenses may be renewed for up to 20 years beyond the 40-year term of the initial license. No limit on the number of renewals is specified. Part 54 requires license renewal applicants to perform specified types of evaluations and assessments of their facility and to provide sufficient information for the NRC to determine whether or not continued operation of the facility during the renewal term will endanger public health and safety or the environment. Specifically, licensees will be required to assess the effect of age-related degradation on certain long-lived, passive systems, structures, and components that are within the scope of Part 54. The assessment results will determine what activities and modifications are necessary at the time of license renewal and throughout the renewal term to ensure continued safe operation of the plant. Most utilities are expected to begin preparation for license renewal about 10 to 20 years before expiration of their original operating licenses. The inspection, surveillance, test, and maintenance programs for license renewal would be integrated gradually into plant operations over a period of years. For the purpose of the analysis in this GEIS, NRC anticipates that plant refurbishment undertaken specifically for license renewal would probably be completed within normal plant outage cycles beginning 8 years before the original license expires and one longer outage, if a major refurbishment item is involved. Activities associated with license renewal and operation of a plant for an additional 20 years are discussed in Chapter 2.
1.3 Purpose and Need for the Action
The Commission will act on an applications for license renewal submitted by a licensee of an operating nuclear power plant. Although a licensee must have a renewed license to operate a plant beyond the term of the existing operating license, the possession of that license is just one of a number of conditions that must be met for the licensee to continue plant operation during the term of the renewed license. State regulatory agencies and the owners of the plant would ultimately decide whether the plant will continue to operate based on factors such as need for power or other matters within the State's jurisdiction or the purview of the owners. Economic considerations will play a primary role in the decision made by State regulatory agencies and the owners of the plant. Thus, for license renewal reviews, the Commission has adopted the following definition of purpose and need:
The purpose and need for the proposed action (renewal of an operating license) is to provide an option that allows for power generation capability beyond the term of a current nuclear power plant operating license to meet future system generating needs, as such needs may be determined by State, utility, and, where authorized, Federal (other than NRC) decision makers.
This definition of purpose and need reflects the Commission's recognition that, absent findings in the safety review required by the Atomic Energy Act of 1954, as amended, or findings in the NEPA environmental analysis that would lead the NRC to reject a license renewal application, the NRC has no role in the energy planning decisions of State regulators and utility officials as to whether a particular nuclear power plant should continue to operate. From the perspective of the licensee and the State regulatory authority, the purpose of renewing an operating license is to maintain the availability of the nuclear plant to meet system energy requirements beyond the term of the plant's current license. The underlying need that will be met by the continued availability of the nuclear plant is defined by various operational and investment objectives of the licensee. Each of these objectives may be dictated by State regulatory requirements or strongly influenced by State energy policy and programs. In cases of interstate generation or other special circumstances, Federal agencies such as the Federal Energy Regulatory Commission (FERC) or the Tennessee Valley Authority (TVA) may be involved in making these decisions. The objectives of the various entities involved may include lower energy cost, increased efficiency of energy production and use, reliability in the generation and distribution of electric power, improved fuel diversity within the State, and environmental objectives such as improved air quality and smaller land use impacts.
1.4 Alternatives to the Proposed Action
In Chapter 8, the Commission has considered the environmental consequences of the no action alternative (i.e., denying a license renewal application) and the environmental consequences of the various alternatives available for replacing the lost generating capacity that would be available to a utility and other responsible energy planners. No conclusions are made in this document about the relative environmental consequences of license renewal or the construction and operation of alternative facilities for generating electric energy. The information in the GEIS is available for use by the NRC and the licensee in performing the site-specific analysis of alternatives. This information will be updated periodically, as appropriate. For individual plant reviews, information codified in the rule, information developed in the GEIS, and any significant new information introduced during the plant-specific review, including any information received from the State or members of the public, will be considered in reaching conclusions in the supplemental EIS. For an individual plant review, the environmental impacts of license renewal are to be compared with those of alternative energy sources so as to determine whether the adverse environmental impact of license renewal are so great that preserving the option of license renewal for energy planning decision makers would be unreasonable.
1.5 Analytical Approach Used in the GEIS
The GEIS summarizes the approach and findings of a systematic inquiry into the potential environmental consequences of renewing the licenses and operating individual nuclear power plants an additional 20 years. The inquiry identified the attributes of the nuclear power plants, such as major features and plant systems, and the ways the plants can affect the environment. The inquiry also identified the possible refurbishment activities and modifications to maintenance and operating procedures that might be undertaken given the requirements of the safety review as provided for in the Commission's regulations 10 CFR Part 54 or given a utility's motivation for increased economic efficiency. To identify possible initiators of environmental impacts, two scenarios were developed from the possible set of refurbishment activities and continuation of plant operation during the renewal term. One scenario was developed as a typical but somewhat conservative scenario for license renewal, intended to be representative of the type of programs that many licensees seeking license renewal might implement. The other scenario is highly conservative, encompassing considerably more activities, and is intended to characterize a reasonable upper bound of impact initiators that might result from license renewal. These scenarios are discussed in Chapter 2 and in more detail in Appendix B. The linkages between the impact initiators and the environment and the potential environmental impact consequences are developed in the other chapters of the GEIS.
Previous experience with nuclear power plant operation and refurbishment was reviewed in developing the possible scope of environmental impacts that complemented the identification of impact initiators and linkages to the environment. This experience is found in a variety of sources. A list of possible impacts is found in NUREG-0099, Regulatory Guide 4.2, Rev. 2 (July 1976) and in NUREG-0555, "Environmental Standard Review Plans for the Environmental Review of Construction Permit Applications for Nuclear Power Plants" (May 1979). Information was gathered from the environmental impact statements prepared for individual plants at the construction permit and operating license stages. A survey of individual plant operating and refurbishment experience was designed by Oak Ridge National Laboratory (ORNL) and the NRC staff and was administered by the Nuclear Energy Institute (NEI), formerly the Nuclear Utility Management and Resources Council (NUMARC). ORNL analysts reviewed the literature relevant to nuclear power plant impacts on the environment and surveyed by telephone and letter federal, state, and local authorities who have responsibilities that would make them cognizant of the environmental impacts of individual nuclear power plants. The information gathered for this GEIS was supplemented at several stages by comments and information provided by various interests groups at public workshops and by written comments in response to information noticed in the Federal Register. The NRC staff's responses to comments are provided in NUREG-1529, Public Comments on the Proposed 10 CFR Part 51 Rule for Renewal of Nuclear Power Plant Operating Licenses and Supporting Documents; Review of Concerns and NRC Staff Response.
The general analytical approach to each environmental issue was to (1) describe the activity that affects the environment, (2) identify the population or resource that is affected, (3) assess the nature and magnitude of the impact on the affected population or resource, (4) characterize the significance of the effect for both beneficial and adverse effects, (5) determine whether the results of the analysis applies to all plants, and (6) consider whether additional mitigation measures would be warranted for impacts that would have the same significance level for all plants.
A standard of significance was established for assessing environmental issues; and, because significance and severity of an impact can vary with the setting of a proposed action, both "context" and "intensity" as defined in the Council on Environmental Quality regulations (40 CFR 1508.27) were considered. With these standards as a basis, each issue was assigned to one of the three following significance levels:
- Small: For the issue, environmental effects are not detectable or are so minor that they will neither destabilize nor noticeably alter any important attribute of the resource. For the purposes of assessing radiological impacts, the Commission has concluded that those impacts that do not exceed permissible levels in the Commission's regulations are considered small.
- Moderate: For the issue, environmental effects are sufficient to alter noticeably but not to destabilize important attributes of the resource.
- Large: For the issue, environmental effects are clearly noticeable and are sufficient to destabilize important attributes of the resource.
The discussion of each environmental issue in the GEIS includes an explanation of how the significance category was determined. For issues in which probability of occurrence is a key consideration (i.e., accident consequences), the probability of occurrence has been factored into the determination of significance. In determining the significance levels it was assumed that ongoing mitigation measures would continue and that mitigation measures employed during plant construction would be employed during refurbishment, as appropriate. The potential benefits of additional mitigation measures were not considered in determining significance levels.
In addition to determining the significance of environmental impacts associated with an issue for that issue, a determination was made whether the analysis in the GEIS could be applied to all plants and whether additional mitigation measures would be warranted. The categories to which an issue may be assigned follow.
- Category 1: For the issue, the analysis reported in the Generic Environmental Impact Statement has shown:
- (1)the environmental impacts associated with the issue have been determined to apply either to all plants or, for some issues, to plants having a specific type of cooling system or other specified plant or site characteristics;
- (2)a single significance level (i.e., small, moderate, or large) has been assigned to the impacts (except for collective off-site radiological impacts from the fuel cycle and from high-level waste and spent fuel); and
- (3)mitigation of adverse impacts associated with the issue has been considered in the analysis and it has been determined that additional plant-specific mitigation measures are likely not to be sufficiently beneficial to warrant implementation.
The generic analysis of the issue may be adopted in each plant-specific review.
- Category 2: For the issue, the analysis reported in the GEIS has shown that one or more of the criteria of Category 1 cannot be met, and therefore, additional plant-specific review is required.
If, for an environmental issue, the three Category 1 criteria apply to all plants, that issue is Category 1, and the generic analysis should be used in a license renewal review for all plant applications and supplemental environmental impact statements. If the three Category 1 criteria apply to a subset of plants that are readily defined by a common plant characteristic, notably the type of cooling system, the population of plants is partitioned into the set of plants with the characteristic and the set without the characteristic. For the set of plants with the characteristic, the issue is Category 1, and the generic analysis should be used in the license renewal review for those plants. For the set of plants without the characteristic, the issue is Category 2, and a site-specific analysis for that issue will be performed as part of the license renewal review. The review of a Category 2 issue may focus on the particular aspect of the issue that causes the Category 1 criteria not to be met. For example, severe accident mitigation design alternatives under the issue "severe accidents" is the focus for a plant-specific review because the other aspects of the issue, specifically the off-site consequences, have been adequately addressed in the GEIS.
1.6 Scope of the GEIS
This final GEIS assesses 92 environmental issues. Sixty-eight of these issues are found to be Category 1 and are identified in 10 CFR Part 51 as not requiring additional plant-specific analysis. Guidance on the analyses required for each of the other 24 issues is provided in 10 CFR Part 51. A summary of the findings for the 92 environmental issues is provided in Table 9.1 of this GEIS. That table has been codified in Appendix B to Subpart A of 10 CFR Part 51 (Table B-1).
Preparing the plants for an additional 20 years of operations is an important factor in assessing the type and extent of environmental impacts. Consequently, Chapter 2 describes (1) the two scenarios that were developed to characterize refurbishment activities to prepare the plant for operations during the license renewal term and (2) the possible differences between past operations and anticipated operations during the license renewal period. With Chapter 2 as a basis, Chapter 3 projects and assesses the potential environmental impacts associated with refurbishment; and Chapter 4 examines the potential environmental impacts associated with operations during the license renewal period. In most ways, the environmental effects of license renewal are found to be similar to those of normal operations.
The implications for license renewal on the environmental impacts associated with accidents, the uranium fuel cycle and waste management, and decommissioning are discussed in separate chapters. Chapter 5 addresses the ways in which the impacts of potential design basis and severe accidents may be affected by operation of the plants for an additional 20 years. Chapter 6 discusses the extent to which license renewal and an additional 20 years of operation will affect the environmental impacts related to the uranium fuel cycle and the management (storage and disposal) of nonradioactive solid waste, low-level radioactive waste, mixed waste (radioactive and chemically hazardous), spent fuel, and transportation of radioactive wastes as generated at a plant. Chapter 7 assesses the extent to which the license renewal and an additional 20 years of operation would affect the environmental impacts of decommissioning a plant.
Chapter 8 describes the potential environmental effects of terminating plant operations at the end of the current license term and the effects that would be associated with various alternative sources of energy. Because many environmental impacts of energy technologies are site specific, this chapter reaches no conclusions about the significance of these effects nor does it reach any conclusions about the preferability of license renewal or any alternative to it. The information in this chapter is intended to serve as an aid for preparers of plant-specific license renewal impact assessments.
Finally, Chapter 9 summarizes the analytical findings reached in this GEIS.
1.7 Implementation of the Rule
1.7.1 General Requirements
The regulatory requirements for performing a NEPA review for a license renewal application are similar to the NEPA review requirements for other major plant licensing actions. Consistent with the current NEPA practice for major plant licensing actions, an applicant is required to submit an environmental report that analyzes the environmental impacts associated with the proposed action, considers alternatives to the proposed action, and evaluates any alternatives for reducing adverse environmental effects. Additionally, the NRC staff is required to prepare a supplemental environmental impact statement for the proposed action, issue the statement in draft for public comment, and issue a final statement after considering public comments on the draft. These requirements are found in the Commissions regulations at 10 CFR Part 51.
The review requirements for license renewal deviates from NRC's traditional NEPA review practice in some areas. First, the amendment codifies certain environmental impacts associated with license renewal that are analyzed in this GEIS. Accordingly, additional analyses for certain impacts codified by this rulemaking need not be presented in an applicant's environmental report for license renewal nor in the Commission's (including NRC staff, adjudicatory officers, and the Commission itself) draft and final SEIS and other environmental documents developed for the proceeding. Secondly, the amendment reflects the Commission's decision to limit its NEPA review for license renewal to a consideration of the environmental effects of the proposed action and alternatives to the proposed action. Finally, the amendment contains a decision standard that the Commission will use in determining the acceptability of the environmental impacts of individual license renewals.
The Commission and the applicant will also in some cases (e.g., severe accident consequences) consider alternatives to reduce or mitigate environmental impacts. The Commission has concluded that, for license renewal, the issues of need for power and utility economics should be reserved for State and utility officials to decide. Accordingly, the NRC will not conduct an analysis of these issues in the context of license renewal or perform traditional cost-benefit balancing in license renewal NEPA reviews. Finally, the rule does not codify any conclusions regarding the subject of alternatives. Consideration of and decisions regarding alternatives will occur at the site-specific stage.
1.7.2 Applicant's Environmental Report
The applicant's environmental report must contain an analysis of the environmental impacts of renewing a license, the environmental impacts of alternatives, and mitigation alternatives. In preparing the analysis of environmental impacts contained in the environmental report, the applicant should refer to the data provided in 10 CFR Part 51, Appendix B. The applicant is not required to provide an analysis in the environmental report of those issues identified as Category 1 issues in Table B-1 in Appendix B. For those issues identified as Category 2 in Table B-1, the applicant must provide a specified additional analysis beyond that contained in Table B-1. Section 10 CFR 51.53(c)(3)(ii) specifies the subject areas of the analysis that must be addressed for the Category 2 issues.
Pursuant to 10 CFR 51.45(c), 10 CFR 51.53(c)(2) requires the applicant to consider possible actions to mitigate the adverse impacts associated with the proposed action. This consideration is limited to designated Category 2 matters. Pursuant to 10 CFR 51.45(d), the environmental report must include a discussion of the status of compliance with applicable Federal, State, and local environmental standards. Also, 10 CFR 51.53(c)(2) specifically excludes from consideration in the environmental report the issues of need for power, the economic costs and benefits of the proposed action, economic costs and benefits of alternatives to the proposed action, or other issues not related to environmental effects of the proposed action and associated alternatives. In addition, the requirements in 10 CFR 51.45 are consistent with the exclusion of economic issues in 10 CFR 51.53(c)(2).
Pursuant to 10 CFR 51.45(c), 10 CFR 51.53(c)(2) requires the applicant to consider the environmental impacts of alternatives to license renewal in the environmental report. The treatment of alternatives in the environmental report should be limited to the environmental impacts of such alternatives. The amended regulations do not require a discussion of the economic costs and benefits of these alternatives in the environmental report for the operating license renewal stage except as necessary to determine whether an alternative should be included in the range of alternatives considered or whether certain mitigative actions are appropriate. The analysis should demonstrate consideration of a reasonable set of alternatives to license renewal. In preparing the alternatives analysis, the applicant may consider information regarding alternatives in this GEIS.
The Commission has developed a new approach to making decisions for environmental impact statements for license renewal. This decision standard differs from past Commission practice. The amended regulations for license renewal do not require applicants to apply this decision standard to the information generated in their environmental report (although the applicant is not prohibited from doing so if it desires). Under NEPA, the Commission has the final authority and responsibility for making such a decision regarding the environmental acceptability of the proposed renewal license. However, the NRC staff will use the information contained in the environmental report in preparing the environmental impact statement upon which the Commission will base its final decision.
Consistent with the NRC's current NEPA practice, an applicant must include alternatives to reduce or mitigate adverse environmental impacts in its environmental report. However, for license renewal, the Commission has generically considered mitigation for environmental issues associated with renewal and has concluded that no additional site-specific consideration of mitigation is necessary for many issues. The Commission's consideration of mitigation for each issue included identification of current activities that adequately mitigate impacts and an assessment as to whether certain impacts are so insignificant that mitigation is not warranted. The Commission has considered mitigation for all impacts designated as Category 1 in Table B-1. Therefore, a license renewal applicant need not address mitigation for Category 1 issues in Table B-1.
1.7.3 The NRC's Supplemental Environmental Impact Statement
The Commission is required to prepare a supplemental environmental impact statement (SEIS), consistent with 10 CFR 51.20(b)(2). This statement will serve as the Commission's independent analysis of the environmental impacts of license renewal as well as a comparison of these impacts to the environmental impacts of alternatives. This document will also present the preliminary recommendation by the NRC staff regarding the proposed action. The provisions in 10 CFR 51.71 and 51.95 to reflect the Commission's approach to addressing the environmental impacts of license renewal in an SEIS.
The issues of need for power, the economic costs and benefits of the proposed action and economic costs and benefits of alternatives to the proposed action are specifically excluded from consideration in the supplemental environmental impact statement for license renewal by 10 CFR 51.95(c), except as these costs and benefits are either essential for a determination regarding the inclusion of an alternative in the range of alternatives considered or relevant to mitigation. The environmental report does not need to discuss issues related to other than environmental effects of the proposed action and associated alternatives. The requirements in 10 CFR 51.71(d) and (e) are consistent with the exclusion of economic issues in 10 CFR 51.95(c). Additionally, 10 CFR 51.95 allows information from previous NRC site-specific environmental reviews, as well as NRC final generic environmental impact statements, to be referenced in supplemental environmental impact statements.
1.7.4 Public Scoping and Public Comments on the SEIS
Consistent with NRC's NEPA practice, the NRC staff will hold a public meeting in order to inform the local public of the proposed action and receive comments. In addition, the SEIS will be issued in draft for public comment in accordance with 10 CFR 51.91 and 51.93. In both the public scoping process and the public comment process, the Commission will accept comments on all previously analyzed issues and information codified in Table B-1 of 10 CFR Part 51, Appendix B, and will determine whether these comments provide any information that is new and significant compared with that previously considered in the GEIS. If the comments are determined to provide new and significant information bearing on the previous analysis in the GEIS, these comments will be considered and appropriately factored into the Commission's analysis in the SEIS. Public comments on the site-specific additional information provided by the applicant regarding Category 2 issues will be considered in the SEIS.
1.7.5 Commission's Analysis and Preliminary Recommendation
The Commission's draft SEIS will include its analysis of the environmental impacts of the proposed license renewal action and the environmental impacts of the alternatives to the proposed action. The Commission will utilize and integrate the codified environmental impacts of license renewal as provided in Table B-1 of 10 CFR Part 51, Appendix B (supplemented by the underlying analyses in the GEIS), and the appropriate site-specific analyses of Category 2 issues and any new issues identified during the scoping and public comment process, to arrive at a conclusion regarding the sum of the environmental impacts associated with license renewal. These impacts will then be compared, quantitatively or qualitatively as appropriate, with the environmental impacts of the considered alternatives. The analysis of alternatives in the SEIS will be limited to the environmental impacts of these alternatives and will be prepared in accordance with 10 CFR 51.71 and of 10 CFR Part 51, Subpart A, Appendix A. The analysis of impacts of alternatives provided in the GEIS may be referenced in the SEIS as appropriate. The alternatives discussed in the GEIS include a reasonable range of different methods for power generation. The analysis in the draft SEIS will consider mitigation actions for designated Category 2 matters and will consider the status of compliance with Federal, State, and local environmental requirements as required by 10 CFR 51.71(d). Consistent with 10 CFR 51.71(e), the draft supplemental environmental impact statement must contain a preliminary recommendation regarding license renewal based on consideration of the information on the environmental impacts of license renewal and of alternative energy sources contained in the SEIS. To reach its recommendation, the NRC staff must determine whether the adverse environmental impacts of license renewal are so great that preserving the option of license renewal for energy planning decision makers would be unreasonable. This requirement is contained in 10 CFR 51.95(c)(4).
1.7.6 Final Supplemental Environmental Impact Statement
The Commission will issue a final supplemental environmental impact statement for a license renewal application in accordance with 10 CFR 51.91 and 51.93 after considering the public comments related to new issues identified from the scoping and public comment process, Category 2 issues, and any new and significant information regarding previously analyzed and codified Category 1 issues. Pursuant to 10 CFR 51.102 and 51.103, the Commission will provide a record of its decision regarding the environmental impacts of the proposed action. In making a final decision, the Commission must determine whether the adverse environmental impacts of license renewal (when compared with the environmental impacts of other energy generating alternatives) are so great that preserving the option of license renewal for energy planning decision makers would be unreasonable.
All comments on the applicability of the analyses of impacts codified in the rule and the analysis contained in the draft supplemental EIS will be addressed by NRC in the final supplemental EIS in accordance with 40 CFR § 1503.2, regardless of whether the comment is directed to impacts in Category 1 or 2. Such comments will be addressed in following manner:
- a. NRC's response to a comment regarding the applicability of the analysis of an impact codified in the rule to the plant in question may be a statement and explanation of its view that the analysis is adequate including, if applicable, consideration of the significance of new information. A commenter dissatisfied with such a ay file a petition for rulemaking under 10 CFR § 2.802. Procedures for the submission of petitions for rulemaking are explained in Appendix I. If the commenter is successful in persuading the Commission that the new information does indicate that the analysis of an impact codified in the rule is incorrect in significant respects (either in general or with respect to the particular plant), then a rulemaking proceeding will be initiated.
- b. If the commenter provides new information that is relevant to the plant and is also relevant to other plants (i.e., generic information) and that information demonstrates that the analysis of an impact codified in the final rule is incorrect, the NRC staff will seek Commission approval either to suspend the application of the rule on a generic basis with respect to the analysis or to delay granting the renewal application (and possibly other renewal applications) until therule can be amended. The updated GEIS would reflect the corrected analysis and any additional consideration of alternatives as appropriate.
- c. If a commenter provides new, site-specific information that demonstrates that the analysis of an impact codified in the rule is incorrect with respect to the particular plant, then the NRC staff will seek Commission approval to waive the application of the rule with respect that analysis in that specific renewal proceeding. The supplemental EIS would reflect the corrected analysis as appropriate.
NUREG-1529, Public Comments on the Proposed 10 CFR Part 51 Rule for Renewal of Nuclear Power Plant Operating Licenses and Supporting Documents; Review of Concerns and NRC Response, U.S. Nuclear Regulatory Commission, Washington, D.C., to be published.