NRC: Generic Environmental Impact Statement for License Renewal of Nuclear Plants (NUREG-1437 Vol. 1) - Part 3
3. Environmental Impacts from Nuclear PowerPlant Refurbishment
This chapter addresses the environmental impacts of refurbishment activities at an operating nuclear power plant in anticipation of license renewal. Section 2.4 describes the activities to be undertaken to prepare a nuclear power plant for operation following license renewal (see Tables 2.6 and 2.7). These activities will include (1) enhanced inspection, surveillance, testing, and maintenance and (2) repair, replacement, modification, and refurbishment of plant systems, structures, and components. For some plants, replacement of large components of the nuclear steam supply system (e.g., steam generator or pressurizer) is conceivable, as is repair or replacement of pumps, pipes, control rod systems, electronic circuitry, electrical and plumbing systems, or motors. Upgrading radioactive waste storage facilities could also be required because of increased low-level radioactive waste (LLW) generation and because a permanent high-level-waste repository is not yet available. Construction of new transmission lines is not expected to occur in conjunction with license renewal, although repair or replacement of structures may be needed occasionally. For example, wooden-pole structures may need rebuilding or replacement every 50-60 years. If construction of new lines is proposed, the impacts would be reviewed in accordance with the requirements of 10 CFR Part 51.
Refurbishment activities could result in environmental impacts beyond those that occur during normal plant operation. For example, site excavation and grading associated with construction of new waste storage facilities could result in fugitive dust emissions, localized air quality impacts, erosion, sedimentation, and disturbance of both aquatic and terrestrial ecosystems. Moreover, refurbishment could (1) require a sizable addition to the work force, (2) increase the radiation exposure to workers, and (3) generate increased quantities of LLW. These potential impacts are evaluated in the sections that follow.
3.2 On-Site Land Use
Farming and other types of land use occur on some nuclear plant sites. Some utilities have designated portions of their nuclear plant sites for land uses such as recreation, management of natural areas, and wildlife conservation. Changes in on-site land use at a nuclear plant could result if additional new spent fuel and interim LLW storage facilities were required. (Waste generation, handling, and disposal are discussed in Chapter 6.) Incremental land use resulting from license renewal-related activities, even major refurbishments, is expected to be modest. The greatest land use needs for such activities are projected to occur during the major refurbishment outages of the conservative license renewal scenarios. Major activities such as steam generator replacement in pressurized-water reactors (PWRs), recirculation piping replacement in boiling-water reactors (BWRs), replacement of some reactor vessel internal structures, main turbine repairs, and general structural refurbishments are projected to occur for a few reactor plants during these outages.
Incremental land use associated with license renewal activities can be estimated from prior related experience within the U.S. nuclear industry. For example, a recent steam generator replacement at a U.S. PWR required about 1 ha (~2.5 acres) of land area to accommodate laydown, staging, handling, temporary storage, personnel processing, mockup and training, and related needs. The major activities projected to occur for the conservative license renewal scenarios are expected to require temporary land use for activities such as staging of new components and removing old components. In addition, the large number of temporary workers needed to accomplish the major refurbishment activities will likely require that temporary facilities be installed for on-site parking, training, site security access, office space, change areas, fabrication shops, mockups, and related needs. Based on previous experience with major refurbishments at nuclear power plants, it is expected that ~1-4 ha (~2.5-10 acres) of land may be needed to accommodate these refurbishment activities. Once these major activities and the major outages are completed, this land might be returned to its prior uses. Alternatively, the land could be used for on-site storage of LLW, spent fuel, and contaminated components such as steam generators until final off-site disposal is possible. Thus, some or all of the same land may be used both for the temporary major refurbishment needs and for the longer-term needs associated with on-site storage of waste materials. However, radioactive wastes are stored in remote parts of the site by some utilities in order to minimize worker radiation exposure and to avoid interference with routine activities. Typical license renewal scenario incremental land use requirements are bounded by those projected for the conservative scenarios.
The site is already owned by the utility and any land used for refurbishment activities will likely be within the exclusion area. Even if the land used for dry storage of spent fuel is on a remote part of the site, the impacts will be small. The U.S. Nuclear Regulatory Commission (NRC) has written a number of environmental assessments for on-site dry cask storage facilities and has reached a "finding of no significant impact" (FONSI) for each. The FONSI was reached considering the amount of land actually disturbed, the range of possible environmental impacts, and alternative uses of the land. On-site land use impacts are expected to be of small significance at all sites. Temporary disturbance of land may be mitigated by restoration to its original condition after refurbishment, or after site decommissioning. This is a Category 1 issue.
3.3 Air Quality
Most plant refurbishment activities associated with license renewal would be performed on equipment inside existing buildings and would not generate atmospheric emissions. The only potential sources of impacts to air quality would be (1) fugitive dust from site excavation and grading for construction of any new waste storage facilities and (2) emissions from motorized equipment and workers' vehicles.
Air quality impacts from these sources would be minor and of short duration. The disturbed area for the waste storage facilities and laydown areas, if required, is expected to be 4 ha (10 acres) or less (Section 3.2). During site excavation and grading, some particulate matter in the form of fugitive dust would be released into the atmosphere, but fugitive dust consists primarily of large particles that settle quickly and thus have minimal adverse public health effects. Because construction would probably occur within an existing plant yard, much less site preparation would be necessary than for a previously undisturbed site. Because of the (1) small size of the disturbed area, (2) relatively short construction period, (3) availability of paved roadways at existing facilities, and (4) use of the best management practices (such as seeding and wetting), fugitive dust resulting from these construction activities should be minimal.
Heavy construction vehicles and other construction equipment would generate exhaust emissions (which would include small amounts of carbon monoxide, oxides of nitrogen, volatile organic compounds, and particulate matter). These would be temporary and localized. Additional emissions would result from the vehicles of up to about 2300 construction, refurbishment, and refueling personnel during most of the 9-month refurbishment outage (Figure B.6). For refurbishment occurring in geographical areas of poor or marginal air quality, these vehicle exhaust emissions could be cause for some concern. The 1990 Clean Air Act Amendments include a provision that no federal agency shall support any activity that does not conform to a state implementation plan designed to achieve the National Ambient Air Quality Standards for criteria pollutants (sulfur dioxide, nitrogen dioxide, carbon monoxide, ozone, lead, and particulate matter less than 10 µm in diameter). On November 30, 1993, the U.S. Environmental Protection Agency (EPA) issued a final rule (58 FR 63214) implementing the new statutory requirements, effective January 31, 1994. The final rule requires that federal agencies prepare a written conformity analysis and determination for each pollutant where the total of direct and indirect emissions caused by a proposed federal action would exceed established threshold emission levels in a nonattainment or maintenance area. An area is designated as nonattainment for a criteria pollutant if it does not meet National Ambient Air Quality Standards for the pollutant. A maintenance area is one that a state has redesignated from nonattainment to attainment.
Based on EPA's interpretation that mobile emissions from workers' vehicles should generally be considered as indirect emissions in a conformity analysis, a screening analysis was performed which indicated that the emissions from 2300 vehicles may exceed the thresholds for carbon monoxide, oxides of nitrogen, and volatile organic compounds (the latter two contribute to the formation of ozone) in nonattainment and maintenance areas. In addition, the amount of road dust generated by the vehicles traveling to and from work would exceed the threshold for particulate matter less than 10 µm in serious nonattainment areas. However, the assumption of adding 2300 workers' vehicles to existing traffic forms an upper bound of potential emissions; in reality, some workers would carpool to the refurbishment sites, while others would be driving to other construction sites if the proposed refurbishment activities were not occurring. In addition, EPA suggests that there may be some flexibility in the rigor of a conformity analysis, particularly with regard to the specific site, the extent of refurbishment, the pollutants which are in nonattainment, the severity of the nonattainment, the state regulatory agency, and the federal agency's control over workers' vehicles. In summary, vehicle exhaust emissions could be cause for some concern, but a general conclusion about the significance of the potential impact cannot be drawn without considering the compliance status of each site and the number of workers expected to be employed during the outage. This is a Category 2 issue.
3.4 Surface Water and Groundwater Quality
3.4.1 Surface Water
Refurbishment could impact surface water quality as a result of the effects of (1) refurbishment- or construction-related discharges to surface water and (2) project-related surface water consumption. Changes in water quality could affect aquatic biota and water uses (fishing, recreation, and water supply).
Because most refurbishment activities would be conducted indoors (Section 2.6), discharges would be readily controlled, thereby minimizing the potential for impacts on surface water quality. The construction of new structures for storage of spent fuel or LLW could require modest amounts of site excavation and grading, but there are no features unique to the refurbishment that would require unusual construction practices. Procedures for the control of nonpoint-source pollution from construction activities as mandated by Section 319 of the Clean Water Act are well known. Mitigative measures were developed at each nuclear power plant site to control impacts during original plant construction. These measures, which are listed in the environmental statements related to the issuance of construction permits, include controlling drainage by ditches, berms, and sedimentation basins; prompt revegetation to control erosion; stockpiling and reusing excavated topsoil; and various other techniques used to control soil erosion and water pollution. These same types of site-specific mitigation measures (often referred to as best management practices) are expected to be implemented during refurbishment to minimize impacts on surface water quality and aquatic biota. Therefore, the potential impacts of refurbishment on surface water quality are expected to be negligible (small) for all plants. Impacts of refurbishment on surface water quality and aquatic biota could be further reduced by additional mitigative measures, such as more stringent construction control techniques. However, because the effects of refurbishment are considered to be of small significance and potential mitigation measures are likely to be costly, the staff does not consider the implementation of mitigation measures beyond "best management practices" to be warranted. This is a Category 1 issue.
Water consumption during refurbishment would not change from pre-refurbishment requirements unless the plant were temporarily shut down. If refurbishment activities resulted in more or longer plant outages than are typical for the facility, both cooling water withdrawals and routine permitted discharges of heat, biocides, or other chemical contaminants in the cooling system effluent would be reduced. The additional quantities of water required during construction for mixing, cleaning, and dust suppression would be negligible. For these reasons, water consumption impact during refurbishment is expected to be of small significance or beneficial for all plants. The only potential mitigation for any increase in water consumption would be to acquire the additional water from some other source. However, because this approach would provide very little, if any, environmental benefit and would be costly, the staff does not consider implementation of additional mitigation to be warranted. This is a Category 1 issue.
No liquid wastes were discharged to groundwater during construction of nuclear power plants, and none is expected to occur during refurbishment. During construction, liquid construction wastes were either temporarily retained in lined evaporation ponds or stored in drums for shipment to off-site disposal facilities. Because liquid construction wastes would be handled similarly during refurbishment no impacts to groundwater quality is expected.
The only impacts on groundwater quality reported during nuclear plant construction resulted from groundwater dewatering associated with deeply excavated building foundations and cooling water canals at sites close to the ocean. Groundwater dewatering at sites near the ocean can adversely affect groundwater quality by inducing saltwater intrusion. Deep excavations and site dewatering would not be required at any plant so no saltwater intrusion or groundwater quality impacts would occur.
Because refurbishment would not affect groundwater quality in any way, refurbishment would neither cause nor contribute to impacts on groundwater at any site. While there are several ways of mitigating adverse impacts to groundwater quality, no mitigation measures are warranted because there would be no adverse impacts to mitigate. This is a Category 1 issue.
3.5 Aquatic Ecology
Aquatic biota could be affected by adverse changes in water quality caused by construction or by changes in plant operation; however, if mitigative measures developed for the site during and since original construction are used, adverse effects on water quality and thus on aquatic biota would be minimal (Section 3.4.1). Potential impacts on aquatic biota from changes in operating conditions of the plant during refurbishment are expected to be small at all sites.
Effects of refurbishment on aquatic organisms are considered to be of small significance if plant-induced changes are localized and populations of aquatic organisms in the receiving waterbody are not reduced. During a major refurbishment outage there would be a reduction or elimination of cooling water withdrawals and discharges of heat, biocides, or other permitted chemicals in the cooling effluent. No adverse effects on aquatic biota would be caused at any power plant by reduced entrainment of organisms into the cooling system, reduced impingement against the intake screens, or reduced discharges of chemicals from any power plant site. Because no adverse effects on aquatic organisms are anticipated during refurbishment, the effects are considered to be of small significance for all plants. Since any effects would be minor and localized, they would not contribute to cumulative impacts. Water quality impacts could be readily controlled using current mitigative measures, and the reduction in cooling system operation during major refurbishment outages would reduce the number of aquatic organisms impacted by entrainment, impingement, and nonradiological discharges. Hence, no mitigation measures beyond those already implemented in the current license period would be needed. The effect of refurbishment on aquatic biota is a Category 1 issue.
3.6 Terrestrial Ecology
The potential loss of plant and animal habitat resulting from laydown areas and possible construction of new waste storage facilities during refurbishment at nuclear power plant sites would be the principal terrestrial ecology concern. The amount of on-site land that could be disturbed would be expected to be ~1-4 ha (2.5-10 acres). No off-site habitat loss would be expected to occur except to the extent that refurbishment may cause increased residential and commercial growth in nearby communities (see Section 3.7.5). No off-site power-line expansions (construction of new lines, upgrading of existing lines, or right-of-way expansion) are expected as part of license renewal; licensees must notify the NRC of such major modifications. Rebuilding wooden pole structures, however, may be necessary about every 50-60 years.
The significance of lost habitat depends on the importance of the plant or animal community involved. Particularly important habitats are wetlands, riparian habitats, staging or resting areas for large numbers of waterfowl, rookeries, restricted wintering areas for wildlife (e.g., winter deer yards), communal roost sites, strutting or breeding grounds of gallinaceous birds, and areas containing rare plant communities (e.g., Atlantic white cedar swamps). Such habitats are uncommon and are unlikely to occur on most plant sites. However, if such resources do occur on plant sites, refurbishment activities should be planned to avoid them to the extent feasible. If no important resource would be affected, the impacts would be considered minor and of small significance. If important resources could be affected by refurbishment activities, the impacts would be potentially significant. Because the significance of ecological impacts cannot be determined without considering site-specific and project-specific details, and because mitigation may be warranted, this is a Category 2 issue.
3.7 Socioeconomic Impacts
This section describes the socioeconomic impacts associated with nuclear power plant refurbishment. Based on a literature search and citation review, the following plant-induced socioeconomic impacts were chosen for in-depth evaluation: changes to local housing (i.e., availability, costs, and characteristics); the magnitude of new nuclear plant tax payments in relation to total revenues in host communities; disruptions of local public services (i.e., education, transportation, public safety, social services, public utilities, and tourism and recreation); changes of local land use and development patterns; local employment levels; and disturbances to historic and aesthetic resources at and around the plant site. Of these socioeconomic impacts only those directly affecting the natural and built environment are carried forward to the decision whether to renew an operating license. The regional economic impact--including income, employment, and taxes--is not considered in the license renewal decision. The impacts discussed in this chapter are only those new impacts expected to be caused by refurbishment-related activities. Impacts are discussed for each plant's "impact" or "study" area, which includes those jurisdictions in which the most pronounced socioeconomic impacts are expected. Plant-induced population growth, while not an impact itself, was studied as a potential influence on a number of the impacts listed above.
For this analysis, the socioeconomic impacts that occurred during construction of seven case study nuclear plants were identified and used to forecast refurbishment-related impacts at the same seven plants. Differences between the construction and refurbishment periods in terms of key impact predictors such as work force size, population, and community infrastructure conditions were factored into the impact analysis. The analysis assumes that no other major construction projects will occur concurrently with plant refurbishment. If other large construction projects are ongoing during refurbishment, the socioeconomic impacts could be greater than those predicted. Because the case study plants (Figure 3.1) were representative of the range of U.S. nuclear plants in terms of a number of key factors (remoteness, population density, geographic region, age of plant), the impacts projected for the seven sites provide upper and lower bounds for the range of impacts that will occur at all plants.
Socioeconomic impacts are site-specific in nature. Therefore, simultaneous relicensing of several nuclear power plants will not have cumulative regional or national impacts. However, if two plants within 80 km (50 miles) of each other are refurbished simultaneously, worker in-migration and the related impacts might be larger. An overview of the socioeconomic research methods used is provided in Appendix C.
Socioeconomic impact analyses, particularly of resources affected by changes in population, are based on work force estimates presented in Chapter 2, Appendix B, and SEA (1995). The conservative scenario work force represents the upper bound of work force requirements for a typical plant. The primary socioeconomic impact analyses are based on the largest estimated work force (i.e., the PWR work force of 2273 persons).1 This peak work force would occur during the 9-month major refurbishment outage immediately before the expiration of the initial operating license (see Appendix B).
After the refurbishment work force has peaked, refueling will be undertaken to prepare for continued plant operation during the license renewal term. Because of uncertainty surrounding the work force numbers, a sensitivity analysis was performed wherein socioeconomic impacts were predicted in response to a work force roughly 50 percent larger than the projected bounding case PWR refurbishment work force (i.e., 3400 workers). The discussion of conclusions for each socioeconomic topic states whether or not the category of impacts expected with the original estimate would change in response to the larger work force.
The estimates for the conservative case and typical case BWR peak work forces are 1500 and 1017, respectively.2 The peak
on-site work force associated with the conservative BWR refurbishment scenario would occur during the current-term outages that will begin up to 10 years before the expiration of the original operating license. Because the current-term outages will last only 4 months, refueling and refurbishment workers will be on-site simultaneously. Both types of workers are included in the estimated peak work force of 1500. Under the BWR typical refurbishment scenario, the peak work force (1017) would occur during the final refurbishment period, projected to last 4 months. Because the outage would be brief, refueling workers will be on-site at the same time as refurbishment workers and are therefore included in the total work force estimate.
Limited additional analyses were conducted to determine if these smaller work forces would cause smaller impacts. These analyses were conducted only for resources found to be subject to potential moderate or large impacts with a work force of 2273 and known not to experience moderate or large impacts with smaller work forces (e.g., associated with refueling/maintenance activities). These analyses are discussed in the education and land use sections (i.e., those resources which, at certain case-study sites, fit the above description).
Population growth is important because it is one of the main drivers of socioeconomic impacts. The population increases resulting from construction-related in-migration at the seven case study plants varied (Table 3.1). Of all U.S. nuclear power plants, Indian Point has the highest combination of population density and proximity to urban centers, whereas Wolf Creek has one of the lowest combinations of the same variables. Consequently, Indian Point and Wolf Creek serve as the lower and upper bounds, respectively, of construction-related growth as a percentage of the case study areas' total populations.
Both the absolute and relative population growths associated with the refurbishment of the case study plants would be less than were experienced during original construction (see Table 3.1). The absolute growth would be smaller because the scale of refurbishment activities would be smaller than original construction. Relative growth would also be smaller because existing populations of the host communities are expected to be larger than during original construction (see Appendix C). The levels of refurbishment-related growth projected for the case study sites are expected to bound the levels of growth that would occur at all other plants.
Table 3.1 Past and projected population growth associated with the peak construction and refurbishment work forces at the seven case study nuclear power plantsa
|Plant||Past population growth caused by original plant construction||Past population growth as a percentage of study area's total population during peak construction years||Projected population growth caused by refurbishment||Projected population growth (refurbishment) as a percentage of study area's projected total population|
|Arkansas Nuclear One||2756||8.3||2355||3.7|
|D. C. Cook|
|Three Mile Island||301||2.2||189||1.0|
aIncludes both direct and indirect workers and their families.
Source: The staff.
Refurbishment-related growth is expected to represent between less than 0.1 percent and 9.1 percent of the local areas' total populations for all plants (Table 3.1). As a result, for most U.S. nuclear power plants, refurbishment would result in only small population increases and correspondingly small population-driven impacts. Rural areas that are more than 80 km (50 miles) from an urban center (i.e., a population of at least 100,000) and that have low population densities would experience greater population-driven impacts.
The impacts on housing are considered to be of small significance when a small and not easily discernible change in housing availability occurs, generally as a result of a very small demand increase or a very large housing market. Increases in rental rates or housing values in these areas would be expected to equal or slightly exceed the statewide inflation rate. No extraordinary construction or conversion of housing would occur where small impacts are foreseen.
The impacts on housing are considered to be of moderate significance when there is a discernible but short-lived reduction in available housing units because of project-induced in-migration. Rental rates and housing values would rise slightly faster than the inflation rate, but prices should realign quickly once new housing units became available or once project-related demand diminished. The new housing units added to the market during construction are easily absorbed into the market once project-related demand diminishes. Minor or temporary conversions of nonliving space to living space, such as converting garages to apartments, may occur. Also, there may be a temporary addition of new mobile home parks or expansions of existing parks.
The impacts on housing are considered to be of large significance when project-related demand for housing units would result in very limited housing availability and would increase rental rates and housing values well above normal inflationary increases in the state. Such increases could make housing unavailable or less affordable to nonproject personnel. Substantial conversions of housing units, such as single-family houses to apartments, as well as substantial overbuilding so that these units cannot be absorbed into the housing market once project demand diminishes are also considered indicative of large impacts.
Housing impacts were evaluated by comparing refurbishment-related housing demand to the projected local housing market (number of units and vacancies). The housing impacts that occurred during original plant construction were considered, as were current housing characteristics (e.g., the existence of multifamily units in the local and neighboring housing markets) and the presence of any growth control measures that limit housing development. The size of the future housing market during the refurbishment period was estimated based on historical housing growth rates in the study areas. Housing demand unrelated to refurbishment was estimated based on the projected population at refurbishment time and the 1990 household size. A complete discussion of these assumptions is provided in Section C.4.1.2. Information concerning original construction-related housing impacts and current housing markets at the seven case study sites was obtained from site-specific NUREG reports, the U.S. Census Bureau, local housing authorities, and interviews with realtors and community development officials (see references in Appendix C).
Table 3.2 summarizes the housing impacts that resulted from original construction of the seven case study plants and lists construction-related housing demand relative to the local housing market, which is one of several factors that influence significance. In most cases, project-related housing demand was so small or the local and regional housing markets were so large that no large impacts resulted. The large housing impacts experienced at Wolf Creek were evidenced by (1) limited or no housing availability, (2) the occupation of previously abandoned housing units and of structures that were not originally intended for residential use, and (3) drastically increased rental costs. At this and other sites, local mobile home parks expanded to meet increased demand. None of the case study plant areas experienced substantial new construction of housing units that were built solely in response to project-related demand for housing. Construction of new housing units was noted at some sites during and before plant construction, but all new units were readily absorbed into the market once project-related demand diminished. The smallest work force that induced large impacts occurred with 640 on-site workers at Wolf Creek during operations-period refuelings (Section 4.7.2). Consequently, a work force as small as 640 may cause large impacts in low population areas but less significant impacts in higher population areas.
Potential refurbishment impacts on housing at each of the case study sites are summarized in Table 3.3. Table 3.3 also includes information about peak housing demand and housing demand relative to the projected number of housing units in each study area, although there is no simple direct relationship between these numbers and significance levels. Projected refurbishment impacts at the case study sites range from small to large. Declining economic conditions in the host communities would not increase the severity of the impact because public revenues are not used to build or maintain the dwellings that plant workers would occupy and because economic decline often is accompanied by a loss of population, which could increase the number of available housing units.
Moderate and large impacts are possible at sites located in rural and remote areas, at sites located in areas that have experienced extremely slow population growth (and thus slow or no growth in housing), or where growth control measures that limit housing development are in existence or have recently been lifted. Because impact significance depends on local conditions that cannot be predicted at this time, housing is a Category 2 issue.
Plant-induced increases to local tax receipts are considered beneficial. The benefits of plant refurbishment to local tax structures were considered by examining the magnitude of potential new tax payments by the nuclear power plants in relation to total revenues in the host community. The new payments could be made directly to local government jurisdictions or indirectly to local government jurisdictions through state tax and revenue sharing programs. A more detailed discussion of the methods used to predict tax impacts is provided in Section C.4.1.3.
|Table 3.2 Summary of housing impacts during construction of seven nuclear power plants in case study|
|Site||Peak housing demand in study area||Housing demand as a percentage of the total number of housing units in the study area||Factors affecting housing impact||Impact on housing|
|Arkansas Nuclear One||858||6.25||Construction-related demand caused temporary housing shortages and increased rents, expansion of housing stock||Moderate|
|D. C. Cook
Existing housing stock and housing growth adequate to meet demand
|Diablo Canyon||1297||2.7||Impact increased by rapidly increasing demand for housing unrelated to project||Moderate|
Very large housing market
|Oconee||167||1.2||Duke power provided on-site housing for 150 workers||Small|
|Three Mile Island||146||2.8||Substantial growth in housing stock occurred unrelated to project demand||Small|
|Wolf Creek||713||18||Low vacancy rate in a small housing market; very large construction-related demand||Large|
|Source: The staff.|
|Table 3.3 Projected housing impacts of refurbishment at the seven case study nuclear power plants|
|Plant||Peak housing demand in the study area||Housing demand as a percentage of housing units in the study area||Projected impacts|
|Arkansas Nuclear One||976||3.8a||Small|
|D. C. Cook
Small to moderate
|Diablo Canyon||1388||0.9||Moderate to largeb|
|Three Mile Island||124||1.7||Small|
aIf the rapid growth in housing that occurred during 1986-1990 continues, demand as a percentage of total housing units would be 3.2 percent. The more conservative estimate is presented in this table and used to determine potential impacts.
bBecause of current growth control measures, a slower growth scenario for San Luis Obispo County (see Appendix C) is used. If these growth control measures remain in effect, the impact to housing would be moderate to large. However, if these growth control measures were removed, impacts would be small.
Source: The staff.
The benefits of taxes are considered to be small when new tax payments by thenuclear plant constitute less than 10 percent of total revenues for local taxing jurisdictions. The additional revenues rovided by direct and indirect plant payments on refurbishment-related improvements result in little or no change in local property tax rates and the provision of public services. The benefits of taxes are considered moderate when new tax payments by the nuclear plant constitute 10 to 20 percent of total revenues for local taxing jurisdictions. The additional revenues provided by direct and indirect plant payments on refurbishment-related improvements result in lower property tax levies and increased services by local municipalities. The benefits of taxes are considered to be large when new tax payments by the nuclear plant represent more than 20 percent of total revenues for local taxing jurisdictions. Local property tax levies can be lowered substantially, the payment of debt for any substantial infrastructure improvements made in the past can easily be made, and future improvements can continue.
Property taxes paid to the municipalities and taxing school districts surrounding the seven case study plants were very small at the start of original plant construction, and income and residential-related property taxes, although increasing rapidly throughout the construction period, were usually not large. Generally, as construction progressed, the assessed value of the nuclear plants increased dramatically; therefore, the property tax payments based on these assessments also increased greatly.
Capital improvements made to plants during the final refurbishment outage very likely would have no effect on taxes until they have been completed; thus, they should cause no tax impacts until the license renewal term. However, the assessed value of the plant is expected to increase before that time because of refurbishment-related capital improvements that occur during current-term outages.
Based on the benefits that occurred as a result of original plant construction, benefits resulting from the increase in direct and indirect tax payments to local jurisdictions during refurbishment would be small to moderate at the case study sites. The magnitude of current tax payments provides an indication of the magnitude of new tax payments. Where existing tax payments account for only a small or moderate share (< 20 percent) of total revenue (see Table 4.13), the new additional tax payments will have only small benefits, especially if the increase in assessed value from capital improvements is small. At sites where the plants currently contribute significantly (> 20 percent) to their respective local jurisdictions' total revenues (see Table 4.13) and where substantial capital improvements greatly increase the assessed value, the new benefits may be moderate.
3.7.4 Public Services
The projected impacts of refurbishment on public services were considered for education, transportation, public safety, social services, level of demand for public utilities, and tourism and recreation.
For most public services, future impacts were projected based on the estimated number of in-migrating workers and on the projected state of the local infrastructure. To predict impacts to local educational systems, the number of in-migrating workers accompanied by their families and their associated family sizes also are important. In the area of transportation, the total number of workers is important whether or not they are new to the host community, because they will use local roads to access the project site. Assumptions about the above-mentioned variables were based on patterns observed during original plant construction. Additional information on the calculation of public service impacts is provided in Sections C.1.5.3 and C.4.1.4. Information concerning construction-related public service impacts and current services at the case study sites was obtained from site-specific reports and interviews with local officials (see references in Appendix C).
Because projections of infrastructure capacity were based on current conditions, it is appropriate to ask whether future deterioration of host community infrastructure could invalidate the conclusions about impact significance presented below. Infrastructure deterioration is unlikely because these facilities and services generally have been maintained (and in many instances improved) during the period of plant operations. In addition, continued plant operations will ensure continued revenues for those local jurisdictions currently taxing the plant, providing a measure of protection for communities in which economic decline might otherwise result in infrastructure deterioration. Also, in communities where the quality and quantity of public services have declined, a population decrease has often occurred, reducing the demand for these services. Finally, the sensitivity analysis discussed in Section 3.7.1 revealed that local public services could accommodate the growth associated with a work force 50 percent larger than the bounding case refurbishment work force without increasing the significance level of the impacts. As a result, for those elements of the infrastructure projected to experience only small impacts, the capacity of the existing infrastructure in impact area communities could decline and still be adequate to support projected refurbishment-induced growth.
Impact determinations depend on the baseline conditions of the potentially affected school system (e.g., whether it is below, at, or exceeding maximum allowed student/teacher ratio). In general, small impacts are associated with project-related enrollment increases of 3 percent or less. Impacts are considered small if there is no change in the school systems' abilities to provide educational services and if no additional teaching staff or classroom space is needed. Moderate impacts generally are associated with 4 to 8 percent increases in enrollment. Impacts are considered moderate if a school system must increase its teaching staff or classroom space even slightly to preserve its pre-project level of service. Any increase in teaching staff, however small (e.g., 0.5 full-time equivalent), that occurs from hiring additional personnel or changing the duties of existing personnel (e.g., a guidance counselor assuming classroom duties) may result in moderate impacts, particularly in small school systems. Large impacts are associated with project-related enrollment increases above 8 percent. Education impacts are considered large if current institutions are not adequate to accommodate the influx of students or if the project-related demand can be met only if additional resources (e.g., new teachers and/or classrooms) are acquired.
Impacts to education that resulted from plant construction depended upon the number of in-migrating workers (and, thus, school-aged dependents) and the size of the existing school system (and thus its ability to absorb additional students). School districts were affected for a short period of time, and disruption to existing institutions was small in most cases. However, some schools had to set up temporary classrooms to accommodate the influx of children. At the case-study sites, impacts to education during plant construction ranged from small to moderate (see Table 3.4). Once construction was well under way, positive monetary impacts began to be experienced by some school districts where plants were located.
Projected impacts to education during the refurbishment period would be potentially large at Wolf Creek where school enrollment is projected to increase 9 percent because of the in-migration of the refurbishment work force (see Table 3.5). At the Arkansas Nuclear One site, a projected 4 percent increase in enrollment could cause moderate impacts to education. At all other sites, impacts would be small.
Table 3.4 Original construction-induced public service impacts at the seven case study nuclear power plant sites
|Service||Arkansas Nuclear One||Diablo Canyon||D. C. Cook||Indian Point||Oconee||Three Mile Island||Wolf Creek|
|Education||Small||Small to moderate||Small||Small||Small||Small||Moderate|
|Transportation||Small||Small||Small to moderate||Small||Small||Moderate||Large|
|Social services||Small||Small||Small||Small||Small to moderate||Small||Small|
|Public utilities||Small to moderate||Small||Small||Small||Small||Small||Moderate|
|Tourism and recreation||Small||Small||Small||Small||Small||Small||Small to moderate|
Source: The staff.
Table 3.5 Projected refurbishment-induced public service impacts at seven nuclear plant sites in case study
|Service||Arkansas Nuclear One||D. C. Cook||Diablo Canyon||Indian Point||Oconee||Three Mile Island||Wolf Creek|
|Education||Moderate||Small||Small||Small||Small||Small||Moderate to large|
|Public utilities||Small||Small||Small to moderate||Small||Small||Small||Small to moderate|
|Tourism and recreation||Small||Small||Small||Small||Small||Small||Small|
Source: The staff.
Analyses of the smaller projected work forces associated with BWR conservative and BWR typical scenarios were conducted at case-study sites where impacts induced by the PWR conservative scenario work force were projected to be moderate or large. The analyses determine whether these smaller work forces would induce smaller impacts to education. At the most sparsely populated case study site (Wolf Creek), impacts to education would be moderate even with the smaller work forces. At the other site (Arkansas Nuclear One), impacts would be moderate with the 1500-person BWR bounding case work force but small with the 1017-person BWR typical case work force.
Based on the case-study analysis of the PWR bounding-case work force, refurbishment impacts on education at all plant sites would range from small to large, although most sites will experience only small new impacts to education. Analyses of the work forces associated with the BWR bounding- and typical-case scenarios conclude that moderate impacts to education could be induced by these smaller work forces but only at sites that are remotely located and sparsely populated. Because site-specific and project-specific factors determine the significance of impacts to education and the potential value of mitigation measures, this is a Category 2 issue.
Significance levels of transportation impacts are related to the Transportation Research Board's level of service (LOS) definitions (Transportation Research Board 1985). LOS is a qualitative measure describing operational conditions within a traffic stream and their perception by motorists. LOS data, when available, can be obtained from local planners, county engineers, or local or state departments of transportation. Using LOS data describing existing conditions, the staff projected LOS conditions that would arise from the additional traffic associated with refurbishment (or continued operations). The LOS at each site was examined during shift change times when plant- and non-plant-related traffic is heaviest. A general definition of each LOS is provided below.
LOS A and B are associated with small impacts because the operation of individual users is not substantially affected by the presence of other users. At this level, no delays occur and no improvements are needed. LOS C and D are associated with moderate impacts because the operation of individual users begins to be severely restricted by other users and at level D small increases in traffic cause operational problems. Consequently, upgrading of roads or additional control systems may be required. LOS E and F are associated with large impacts because the use of the roadway is at or above capacity level, causing breakdowns in flow that result in long traffic delays and a potential increase in accident rates. Major renovations of existing roads or additional roads may be needed to accommodate the traffic flow.
Impacts to local transportation networks during construction of the case study plants were large only at Wolf Creek (Table 3.4) because of the inadequacy of the main local access roads to accommodate plant-related traffic. Large transportation impacts also are anticipated at Wolf Creek during refurbishment. In this case, current operations workers would contribute to the magnitude of those impacts. The magnitude of impacts experienced at this and the other case study sites depends primarily on the state of the existing road network rather than on the host area population density.
|Level of service||Conditions|
|A||Free flow of the traffic stream; users are unaffected by the presence of others.|
|B||Stable flow in which the freedom to select speed is unaffected but the freedom to maneuver is slightly diminished.|
|C||Stable flow that marks the beginning of the range of flow in which the operation of individual users is significantly affected by interactions with the traffic stream.|
|D||High-density, stable flow in which speed and freedom to maneuver are severely restricted; small increases in traffic will generally cause operational problems.|
|E||Operating conditions at or near capacity level causing low but uniform speeds and extremely difficult maneuvering that is accomplished by forcing another vehicle to give way; small increases in flow or minor perturbations will cause breakdowns.|
|F||Defines forced or breakdown flow that occurs wherever the amount of traffic approaching a point exceeds the amount which can traverse the point. This situation causes the formation of queues characterized by stop-and-go waves and extreme instability.|
Refurbishment impacts to transportation would be small at most sites, but a few sites would experience moderate or large impacts. Because impacts are determined primarily by road conditions existing at the time of the project and cannot be easily forecast, a site-specific review will be necessary to determine whether impacts are likely to be moderate or large and whether mitigation measures may be warranted. Transportation is a Category 2 issue.
18.104.22.168 Public Safety
Impacts on public safety are considered small if there is little or no need for additional police or fire personnel. Impacts are considered moderate if some permanent additions to the police and fire protection forces or some new capital equipment purchases are needed. Impacts are considered to be large if there is a substantial increase in the permanent manpower of police and fire protection forces and in the need to purchase additional vehicles.
No serious disruption of public safety services occurred as a result of original construction at the seven case study sites (Table 3.4). Most communities showed a steady increase in expenditures connected with public safety departments. Tax contributions from the plant often enabled expansion of public safety services in the purchase of new buildings and equipment and the acquisition of additional staff.
Public safety services may experience some benefit from any increase in tax revenue generated by plant improvements during current term outages. Past adverse impacts at the case study sites were found to be small, and nothing in the literature review indicated reason to expect moderate or large impacts. Accordingly, any adverse public safety impacts associated with future plant refurbishment at case study sites would be small.
Based on the case-study analysis, it is determined that there would be little or no need for additional police or fire personnel. Therefore, adverse public safety impacts at all sites would be small. Sensitivity analysis indicated that this conclusion would be true even with a peak work force of 3400 workers. Some minor positive impacts might result because of increased tax payments. Because the impacts are small and the implementation of additional mitigation measures (e.g., additional personnel or capital equipment) would be costly, no mitigation measures beyond those implemented during the current term license would be warranted. Therefore, public safety is a Category 1 issue.
22.214.171.124 Social Services
The impacts on social services are considered small if no change in the current level of service occurs. Impacts are considered moderate if some additional personnel are needed to administer existing service programs. Impacts are considered large if new programs and additional personnel are required.
Impacts to local social services associated with the original construction of the case study plants generally were small (Table 3.4), but some areas did see a small increase in both the amount of dollars spent for new or existing programs and the demand for service during the construction period.
Based on original construction experience at case study plants, the staff anticipates that refurbishment-related population increases would lead to no change in the current levels of social service provided (Table 3.5). Consequently, the impacts of refurbishment on social services would be small at all sites. Because there would be no change in the levels of service and because mitigation measures (e.g., hiring additional social service personnel) beyond those implemented during the current term license would be costly, no mitigation measures would be warranted. This is a Category 1 issue. Sensitivity analysis indicates that this conclusion would be true even with a peak of 3400 workers.
126.96.36.199 Public Utilities
Impacts on public utility services are considered small if little or no change occurs in the ability to respond to the level of demand and thus there is no need to add to capital facilities. Impacts are considered moderate if overtaxing of facilities during peak demand periods occurs. Impacts are considered large if existing service levels (such as the quality of water and sewage treatment) are substantially degraded and additional capacity is needed to meet ongoing demands for services.
In general, small to moderate impacts to public utilities were observed as a result of the original construction of the case study plants (Table 3.4). While most locales experienced an increase in the level of demand for services, they were able to accommodate this demand without significant disruption. Water service seems to have been the most affected public utility.
Public utility impacts at the case study sites during refurbishment are projected to range from small to moderate. The potentially moderate impact at Diablo Canyon is related to water availability (not processing capacity) and would occur only if a water shortage occurs at refurbishment time.
Because the case studies indicate that some public utilities may be overtaxed during peak periods, the impacts to public utilities would be moderate in some cases, although most sites would experience only small impacts. This is a Category 2 issue.
188.8.131.52 Tourism and Recreation
Impacts on tourism and recreation are considered small if current facilities are adequate to handle local levels of demand. Impacts are considered moderate if facilities are overcrowded during peak demand times. Impacts are considered large if additional recreation areas are needed to meet ongoing demands.
In most of the case study areas, the original construction of a nuclear power plant had positive effects on tourism and recreation facilities. For example, some locales have been able to build new recreation facilities because of plant-related tax revenues. Some improvement to recreation facilities and programs may be possible if additional tax revenue is available as a result of current-term refurbishment at the plant. Increased demand associated with the refurbishment work force and in-migrating population is expected to cause only small impacts to recreation at the case-study sites.
Based on the case study analysis, the beneficial impacts of refurbishment would continue at most sites. Sensitivity analysis indicates that this conclusion would be true even with a peak work force of 3400 workers. Current facilities would continue to be adequate to handle local levels of demand at all sites, and developing additional facilities would be costly. Therefore, no mitigation measures (e.g., improving or expanding existing facilities) beyond those implemented during the current term license would be warranted. This is a Category 1 issue.
3.7.5 Off-Site Land Use
The issue evaluated in this section concerns refurbishment-induced changes to local land use and development patterns. Because the value attributed to land-use changes can vary for different individuals and groups, this analysis does not attempt to conclude whether such changes have positive or negative impacts. The methodology used to define impact significance and project impacts is discussed briefly in the introduction to Section 3.7 and is detailed in Section C.4.1.5.
The impacts to off-site land use are considered small if population growth results in very little new residential or commercial development compared with existing conditions and if the limited development results only in minimal changes in an area's basic land-use pattern. Land-use impacts are considered to be moderate if plant-related population growth results in considerable new residential or commercial development and the development results in some changes to an area's basic land-use pattern. The impacts are considered to be large if population growth results in large-scale new residential or commercial development and the development results in major changes in an area's basic land-use pattern.
Although it is difficult to predict the exact nature of land-use impacts that will result from any nuclear plant's refurbishment, the original construction experience at the case study plants provides some key predictors of impacts. Generally, if plant-related population growth is less than 5 percent of the study area's total population, off-site land-use changes would be small, especially if the study area has established patterns of residential and commercial development, a population density of at least 60 persons per square mile (2.6 km2), and at least one urban area with a population of 100,000 or more within 80 km (50 miles).
If refurbishment-related growth is between 5 and 20 percent of the study area's total population, moderate new land-use changes can be expected. Such impacts would most likely occur when the study area has established patterns of residential and commercial development, a population density of 30 to 60 persons per square mile (2.6 km2), and one urban area within 80 km (50 miles).
Small, moderate, and large off-site land-use impacts resulted from the original construction at the study sites. Large impacts resulted during construction at the two sites where lakes were created. Because no major off-site land use conversion would be needed to support the refurbished plants, only small impacts of this sort are expected. Large impacts were not induced at any site by population growth (see Table 3.6 and Appendix C).
Because the residential settlement pattern of the refurbishment work force is expected to be comparable to that of the original construction work force at many nuclear plants, population-driven land-use impacts that have resulted from the original construction can be used to predict some of the off-site land-use impacts of refurbishment. Thus, the staff expects that refurbishment-related population increases will result in small to moderate new off-site land-use impacts for socioeconomic case study plants (see Table 3.6 and Appendix C).
For the case study site where the staff anticipates moderate land-use changes associated with population in-migration, the staff has conducted additional analyses to determine whether smaller work forces would induce smaller impacts. This analysis shows that at this case-study site moderate impacts are possible with the BWR conservative scenario construction work force (1500 persons), but only small impacts are anticipated with the BWR typical scenario construction work force (1017 persons).
Based on predictions for the case study sites, refurbishment at all nuclear plants is expected to induce small or moderate land-use changes. There will be new impacts; but for almost all plants, refurbishment-related population growth would typically represent a much smaller percentage of the local areas' total population than did original construction-related growth. Moderate land use changes are also possible under the BWR conservative scenario, but only small impacts would be associated with the BWR typical scenario. Because future impacts are expected to range from small to moderate, and because land-use changes could be considered beneficial by some community members and adverse by others, this is a Category 2 issue. A sensitivity analysis shows that large changes in land use would not occur even with a 3400-person work force.
|Arkansas Nuclear One
D. C. Cook
Three Mile Island
aLarge impact because lake construction was associated with site development, not because of population growth (see Appendix C).
Source: The staff.
3.7.6 Economic Structure
The issue evaluated in this section concerns the impact of plant refurbishment on local employment and income levels.
Economic effects are considered small if peak refurbishment-related employment accounts for less than 5 percent of total study area employment. Effects are considered moderate if peak refurbishment-related employment accounts for 5 to 10 percent of total study area employment. Effects are considered large if peak refurbishment-related employment accounts for more than 10 percent of total study area employment. In this context, "plant-related employment" refers to area residents employed at the nuclear power plant or at indirect jobs resulting from a nuclear plant's presence. Employees who live outside the study area and work at the plant are not included.
The study of economic structure examines employment because of its preeminent role in determining the economic well-being of an area. Economic impacts at the case study plants were predicted by comparing the number of direct and indirect jobs created by a plant's refurbishment with the total employment of the local study area at the time of refurbishment. These impacts are considered positive. The potential economic impacts of plant refurbishment at all sites were projected based on the seven case study plants.
During original construction, plant-related employment represented 0.3-25.6 percent of total employment in the communities near the case study plants. Table 3.7 shows the past effects associated with the construction work force and the projected effects of the refurbishment work force for all seven case study sites. The impacts to economic structure of both direct and indirect employment were included in this assessment.
Based on the findings at the case study sites, refurbishment-related economic effects would range from small benefits to moderate benefits at all nuclear plant sites. No adverse effects to economic structure would result from refurbishment-related employment. This conclusion would apply in the event of a much larger refurbishment work force because the associated impacts are beneficial.
3.7.7 Historic and Archaeological Resources
For this discussion and that in Section 4.7.7, historic resources are considered to be any prehistoric or historic archaeological site or historic property, district, site, or landscape in or eligible for inclusion in the National Register of Historic Places or having great local importance.
Sites are considered to have small impacts to historic and archaeological resources if (1) the State Historic Preservation Office (SHPO) identifies no significant resources on or near the site; or (2) the SHPO identifies (or has previously identified) significant historic resources but determines they would not be affected by plant refurbishment, transmission lines, and license-renewal-term operations and there are no complaints from the affected public about altered historic character; and (3) if the conditions associated with moderate impacts do not occur. Moderate impacts may result if historic resources, determined by the SHPO not to be eligible for the National Register, nonetheless are thought by the SHPO or local historians to have local historic value and to contribute substantially to an area's sense of historic character. Sites are considered to have large impacts to historic resources if resources determined by the SHPO to have significant historic or archaeological value would be disturbed or otherwise have their historic character altered through refurbishment activity, installation of new transmission lines, or any other construction (e.g., for a waste storage facility). Determinations of significance of impacts are made through consultation with the SHPO.
Any new construction activity, including building new waste storage facilities, new parking areas, new access roads to existing transmission lines, or new transmission lines, is particularly important to an analysis of impacts to historic and archaeological resources. Therefore, a refurbishment plan detailing areas of land disturbance is necessary to assess the potential impacts. Historic and archaeological resources vary widely from site to site; there is no generic way of determining their existence or significance. Also, additional resources (e.g., an archaeological site) may be identified before refurbishment begins or their historic significance may be newly established (e.g., a historic building). For these reasons, it is not possible to conclude that only small impacts would occur at the case study sties.
In addition, conclusions with respect to potential impacts to historic resources at the case study sites can be drawn only through consultation with the SHPO. The National Historic Preservation Act of 1966, especially Section 106, requires consultation with the SHPO and possibly the Advisory Council on Historic Preservation to determine whether historic and archaeological resources (either in or eligible for inclusion in the National Register of Historic Places) are located in the area and whether they will be affected by the proposed action.
Table 3.7 Past construction-related and projected refurbishment-related employment effects at seven case study nuclear plants.
|Nuclear plant||Plant-related employmenta||Percentage of total study area employment||Magnitude of impact||Percentage of total study area employment in peak refurbishment year||Magnitude of impact|
|Arkansas Nuclear One||964||6.4||Moderate||5.8||Moderate|
|D. C. Cook
|Three Mile Island||259||2.1||Small||6.0||Small|
aIncludes both direct and indirect employment and income for study area residents.
Source: The staff.
It is unlikely that moderate or large impacts to historic resources occur at any site unless new facilities or service roads are constructed or new transmission lines are established. However, the identification of historic resources and determination of possible impact to them must be done on a site-specific basis through consultation with the SHPO. The site-specific nature of historic resources and the mandatory National Historic Preservation Act consultation process mean that the significance of impacts to historic resources and the appropriate mitigation measures to address those impacts cannot be determined generically. This is a Category 2 issue.
3.7.8 Aesthetic Resources
The issues evaluated in this section concern the impacts of construction and refurbishment activities on aesthetic resources at and around nuclear power plants. Primarily, aesthetic impacts would be temporary, would be limited both in terms of land disturbance and the duration of activity, and would have characteristics similar to those encountered during industrial construction: dust and mud around the construction site, traffic and noise of trucks, and construction disarray on the site itself. If severe, these effects could have implications for the economic and social institutions and functions of communities. Aesthetic resources are the physical elements that are pleasing sensory stimuli and include natural and manmade landscapes and the way the two are integrated. In this evaluation, the staff considers aesthetic resources to be primarily visual.
Levels of impacts for aesthetic resources are defined largely by the impact of the proposed changes as perceived by the public, not merely the magnitude of the changes themselves. The potential for significance arises with the introduction (or continued presence) of an intrusion into an environmental context resulting in measurable changes to the community (e.g., population declines, property value losses, increased political activism, tourism losses).
Sites are considered to have small impacts on their host communities' aesthetic resources if there are (1) no complaints from the affected public about a changed sense of place or a diminution in the enjoyment of the physical environment and (2) no measurable impact on socioeconomic institutions and processes. Sites are considered to have moderate impacts on their host communities' aesthetic resources if there are (1) some complaints from the affected public about a changed sense of place or a diminution in the enjoyment of the physical environment and (2) measurable impacts that do not alter the continued functioning of socioeconomic institutions and processes. A site is considered to have large impacts on its host community's aesthetic resources if there are (1) continuing and widely shared opposition to the plant's continued operation based solely on a perceived degradation of the area's sense of place or a diminution in the enjoyment of the physical environment and (2) measurable social impacts that perturb the continued functioning of community institutions and processes.
Because refurbishment would not result in substantial physical changes to existing plants and because the duration of these activities is expected to be short, new aesthetic impacts are expected to be limited to temporary effects. Based on projections for the case study sites, noticeable impacts on aesthetic resources from refurbishment activities could occur only at those sites where well-recognized aesthetic resources have been identified and protected by community organizations. Insignificant levels of impact on aesthetic resources are likely to be experienced in most host communities where (1) no scenic protection organizations are active, (2) active organizations view refurbishment activities as nonthreatening to such resources, or (3) either few or no distinctive aesthetic resources exist or refurbishment activities are not perceived to be threatening to local resources.
Refurbishment activities will be conducted on-site and primarily within existing buildings. Other than a possible increase in local traffic, due to refurbishment workers, refurbishment activities are not expected to be readily noticeable from off-site viewpoints at any plant. Thus, without a visual intrusion within the physical environment there is no stimulus that could lead to complaints from the public about a changed sense of place or a diminution in the enjoyment of the physical environment and measurable impact on socioeconomic institutions and processes. For these reasons, the impact on aesthetic resources is found to be small. Because there will be no readily noticeable visual intrusion, consideration of mitigation is not warranted. Aesthetic impacts of refurbishment is a Category 1 issue.
3.8 Radiological Impacts
Radiological impacts include off-site dose to members of the public and on-site dose to the work force. Each of these impacts is generic to all light-water reactors (LWRs). Section 2.6 and Appendix B identify the changing out of steam generators at PWRs and the replacement of recirculation piping at BWRs as the major anticipated refurbishment activities. Public radiation exposures and occupational radiation exposures from refurbishment activities for license renewal can be evaluated on the basis of information derived from past occurrences and projections for other repairs. Effluents anticipated during major refurbishment events were estimated on the basis of historical information derived for steam generator changeouts at PWRs and replacements of recirculation piping at BWRs, refurbishment tasks that have already taken place several times within the LWR power reactor industry. From these estimates, the maximum individual and average doses to members of the public were compared with the design objective of Appendix I to 10 CFR Part 50 and with baseline effluents produced during normal reactor operations. Occupational exposures were similarly estimated on the basis of detailed reports of major refurbishment or replacement actions. The radiological significance of the doses caused by refurbishment was compared with doses from normal operation, and risks from occupations not associated with ionizing radiation. Major historical refurbishment actions are referred to in Section 2.6 and are described in detail in Appendix B. Radiological impacts of transportation are discussed in Chapter 6.
A detailed discussion is provided in Chapter 6 of the radiological impacts of low-level waste, mixed waste, and spent fuel generated by power reactors during the renewal period; the impacts attributable to the uranium fuel cycle; and the impacts of the transportation of fuel and waste.
In response to comments on the draft generic environmental impact statement (GEIS) and the proposed rule, the standard defining a small radiological impact has changed from a comparison with background radiation to sustained compliance with the dose and release limits applicable to the activities being reviewed. This change is appropriate and strengthens the criterion used to define a small environmental impact for the reasons that follow. The Atomic Energy Act requires NRC to promulgate, inspect, and enforce standards that provide an adequate level of protection of the public health and safety and the environment. These responsibilities, singly and in the aggregate, provide a margin of safety. The definitions of the significance level of an environmental impact (small, moderate, or large) applied to most other issues addressed in this GEIS are based on an ecological model that is concerned with species preservation, ecological health, and the condition of the attributes of a resource valued by society. Generally, these definitions place little or no weight on the life or health of individual members of a population or an ecosystem. However, health impacts on individual humans are the focus of NRC regulations limiting radiological doses. A review of the regulatory requirements and the performance of facilities provides the bases to project continuation of performance within regulatory standards. For the purposes of assessing radiological impacts, the Commission has concluded that impacts are of small significance if doses and releases do not exceed permissible levels in the Commission's regulations. This definition of "small" applies to occupational doses as well as to doses to individual members of the public. Accidental releases or noncompliance with the standards could conceivably result in releases that would cause moderate or large radiological impacts. Such conditions are beyond the scope of regulations controlling normal operations and providing an adequate level of protection. Given current regulatory activities and past regulatory experience, the Commission has no reason to expect that such noncompliance will occur at a significant frequency. To the contrary, the Commission expects that future radiological impacts from the fuel cycle will represent releases and impacts within applicable regulatory limits.
3.8.1 Public Exposures
This section addresses the impacts on members of the public of radiation doses caused by refurbishment activities, including doses from effluents as well as from direct radiation. This issue is generic to all 118 nuclear power plants. To determine the relative significance of the estimated public dose for refurbishment, the staff compared dose projections for refurbishment with the historical (baseline) doses experienced at PWRs and BWRs. The dose estimates were based on reports evaluating effluent releases during refurbishment efforts (projected and measured).
Evaluating and analyzing public exposures to radioactive emissions associated with refurbishment was done in light of the regulatory requirements for nuclear power plants, methods for calculating doses from gaseous and liquid effluents, the levels of risk that authoritative agencies have determined to be associated with radiation exposure, and baseline radiation exposure data.
184.108.40.206 Regulatory Requirements
Nuclear power reactors in the United States must be licensed by the NRC and must comply with NRC regulations and conditions specified in the license in order to operate. NRC regulations in 10 CFR Part 20 include requirements that apply to all licenses such as individual nuclear power plants. In particular, maximum allowable concentrations of radionuclides in air and water above background at the boundary of unrestricted areas are specified to control radiation exposures of the public and releases of radioactivity. These concentrations are based on an annual total effective dose equivalent of 0.1 rem to individual members of the public. (A discussion of the International System of units used in measuring radioactivity and radiation dose is given in Appendix E, Section E.A.3.) In addition, design criteria and technical specifications concerning releases from the plant are required to minimize the radiological impacts associated with plant operations to levels as low as reasonably achievable (ALARA).
In 10 CFR Part 50.36a, conditions are imposed on licensees in the form of technical specifications on effluents from nuclear power reactors. These specifications are intended to keep releases of radioactive materials to unrestricted areas during normal operations, including expected operational occurrences, to ALARA levels. Appendix I to 10 CFR Part 50 provides numerical guidance on dose-design objectives and limiting conditions for operation of LWRs to meet the ALARA requirement. All licensees have provided reasonable assurance that the dose-design objectives are being met for all unrestricted areas. The design objective doses for Appendix I are summarized in Table 3.8.
In addition to NRC limitations, nuclear power plant releases to the environment must comply with EPA standards in 40 CFR Part 190, "Environmental Radiation Protection Standards for Nuclear Power Operations." These standards specify limits on the annual dose equivalent from normal operations of uranium fuel-cycle facilities (except mining, waste disposal operations, transportation, and reuse of recovered special nuclear and byproduct materials). The standards are given in Table 3.8. Radon and its daughters are excluded from these standards.
EPA standards in 40 CFR Part 61, "National Emission Standards for Hazardous Air Pollutants; Regulation of Radionuclides," apply only to airborne releases. The EPA specified an annual effective dose equivalent limit of 10 mrem for airborne releases from nuclear power plants; however, no more than 3 mrem can be caused by any isotope of iodine. However, EPA has stayed the rule for NRC-licensed commercial nuclear power reactors based on its finding that NRC's program for power reactor air effluents protects and is likely to continue to protect the public health and safety with an ample margin of safety.
Experience with the design, construction, and operation of nuclear power reactors indicates that compliance with the design objectives of Appendix I to 10 CFR Part 50 will keep average annual releases of radioactive material in effluents at small percentages of the limits specified in 10 CFR Part 20 and 40 CFR Part 190. At the same time, the licensee is permitted the flexibility of operation, compatible with considerations of health and safety, to ensure that the public is provided a dependable source of power, even under unusual operating conditions that may temporarily result in releases higher than such small percentages but still well within the regulatory limits.
|Table 3.8 Design objectives and annual limits on doses to the general public from nuclear power plantsa|
|Design objectives, 10 CFR Part 50, Appendix I|
|Total body, mrem||5b||3|
|Any organ (all pathways), mrem||10|
|Ground-level air doseb, mrad||10 (gamma)
(all pathways), mrem
|Dose limits, 40 CFR Part 190, Subpart B|
|Total bodyd, mrem||25|
|Any other organd, mrem||25|
bThe ground-level air dose has always been limiting because an occupancy factor cannot be used. The 5-mrem total body objective could be limiting only in the case of high occupancy near the restricted area boundary.
dAll effluents and direct radiation except radon and its daughters.
A major revision of 10 CFR Part 20 became effective in 1991. A significant change is the explicit requirement that the sum of the external and internal doses (total effective dose equivalent) for a member of the public may not exceed 100 mrem/year. This value is an annual limit and is not intended to be applied as a long-term average goal. Summations are to be performed using the methodology in International Commission on Radiological Protection (ICRP) Publication 26 (1977). The revised airborne effluent limits are based on 50 mrem/year. Therefore, with regard to radiation levels at any unrestricted area, the limit of 100 mrem in 7 consecutive days is eliminated, while the limit of 2 mrem in any 1 h is retained. Licensees may comply with the 100-mrem limit by demonstrating (1) by measurement or calculation that the individual likely to receive the highest dose from sources under the licensee's control does not exceed the limit or (2) that the concentrations of radioactive material released in gaseous and liquid effluents averaged over 1 year do not exceed the new levels at the unrestricted area boundary and that the dose in an unrestricted area exceeds neither 2 mrem in any given hour nor 100 mrem in 1 year. It is difficult to judge how federal regulations and industry standards will change between the present time and the license renewal period, which, for the newest reactors, may be 40 years from now. Some indications of future trends can be summarized, however. Two changes are discussed that could significantly affect radiation protection programs at the 118 power plants:
- New ICRP recommendations. ICRP-60 (1991) has recommended an occupational dose limit of 10-rem effective dose equivalent, accumulated over defined periods of 5 years. They have further specified that the effective dose should not exceed 5 rem in any single year. The NRC has carefully reviewed the recommendations of the ICRP and is reviewing the comments of the scientific community and others on these recommendations, and the ICRP response to inquiries. In addition, NRC staff will review the recommendations of other expert bodies, such as the National Council on Radiation Protection and Measurements (NCRP), and participate in the deliberations of the U.S. Committee on Radiation Research and Policy Coordination and any interagency task force convened by the EPA to consider revised federal radiation guidance. Any future reductions in the dose limits by NRC would be the subject of a future rulemaking proceeding.
- NCRP lifetime dose recommendation. NCRP has recommended that a worker's dose in rem should not exceed his age in years. The recommendation was not accepted for the 1991 revision of 10 CFR Part 20. NRC considers that if the magnitude of the annual dose is limited, there is a de facto limitation on the lifetime dose that can be received. The annual dose limit is preferable to an actual cumulative lifetime dose limit because the cumulative limit could act to limit employment, raising questions concerning the right of an individual to pursue employment in a chosen profession. Nonetheless, the Institute of Nuclear Power Operations has expressed considerable interest in the recommendation, and at many plants records are being examined to determine whether the more experienced workers meet this criterion. For those who do not, the utilities may face decisions involving worker protection and liability considerations from a viewpoint favoring restrictions and the need for skilled and experienced workers during the process leading up to and extending throughout the license renewal period.
220.127.116.11 Effluent Pathways for Calculations of Dose Commitment to the Public
When an individual is exposed to radioactive materials through air or water pathways, the dose is determined in part by the amount of time spent in the vicinity of the source or the amount of time the radionuclides inhaled or ingested are retained in the individual's body (exposure). The consequences associated with this exposure are evaluated by calculating the dose commitment. The total effective dose equivalent is the sum of the deep dose from external sources and the committed effective dose equivalent for internal exposures. This latter dose is that which would be received over a 50-year period following the intake of radioactive materials for 1 year under the conditions existing at the midlife of the station operation (typically 15 years).
Radioactive effluents can be divided into several groups based on physical characteristics. Among the airborne effluents, the radioisotopes of the noble gases krypton, xenon, and argon neither deposit on the ground nor are absorbed and accumulated within living organisms; therefore, the noble gas effluents act primarily as a source of direct external radiation emanating from the effluent plume. For these effluents, dose calculations are performed for the site boundary where the highest external-radiation doses to a member of the general public are estimated to occur.
A second group of airborne radioactive effluents--the fission-product radioiodines, as well as carbon-14 and tritium--are also gaseous but some can deposit on the ground or be inhaled during respiration. For this class of effluents, estimates are made of direct external radiation doses from ground deposits (as well as exposure to the plume). Estimates are also made of internal radiation doses to total body, thyroid, bone, and other organs from inhalation and from vegetable, milk, and meat consumption.
A third group of airborne effluents consists of particulates and includes fission products, such as cesium and strontium, and activated corrosion products, such as cobalt and chromium. These effluents contribute to direct external radiation doses and to internal radiation doses through the same pathways as described above for the radioiodine. Doses from the particulates are combined with those from the radioiodines, carbon-14, and tritium for comparison with one of the design objectives of Appendix I to 10 CFR Part 50.
The liquid effluent constituents could include fission products such as strontium and iodine; activation and corrosion products, such as sodium, iron, and cobalt; and tritiated water. These radionuclides contribute to the internal doses through pathways described above from fish consumption, water ingestion (as drinking water), and consumption of meat or vegetables raised near a nuclear plant and using irrigation water, as well as from any direct external radiation from recreational use of the water near the point of a plant's discharge.
The release of each radioisotope and the site-specific meteorological and hydrological data serve as input to radiation-dose models that estimate the maximum radiation dose that would be received outside the facility by way of a number of pathways for individual members of the public and for the general public as a whole. These models and the radiation-dose calculations are discussed in Revision 1 of Regulatory Guide 1.109, "Calculation and Annual Doses to Man from Routine Releases of Reactor Effluent for the Purpose of Evaluating Compliance with 10 CFR Part 50, Appendix I."
Doses from all airborne effluents except the noble gases are calculated for individuals at the location or source point (for example, the site boundary, garden, residence, milk cow or goat, and meat animal) where the highest radiation dose to a member of the public has been established from each applicable pathway (such as ground deposition, inhalation, vegetable consumption, milk consumption, or meat consumption). Only those pathways associated with airborne effluents that are known to exist at a single location are combined to calculate the total maximum exposure to an exposed individual. Pathway doses associated with liquid effluents are combined without regard to any single location but are assumed to be associated with maximum exposure of an individual.
A number of possible exposure pathways to humans are evaluated to determine the impact of routine releases from each nuclear facility on members of the general public living and working outside the site boundaries. A detailed listing of these exposure pathways would include external radiation exposure from the gaseous effluents, inhalation of iodines and particulate contaminants in the air, drinking milk from a cow or goat or eating meat from an animal that grazes on open pasture near the site on which iodines or particulates may be deposited, eating vegetables from a garden near the site (that may be contaminated by similar deposits), and drinking water or eating fish or invertebrates caught near the point of liquid effluent discharge. Other, less important exposure pathways may include external irradiation from surface deposition; eating of animals and crops grown near the site and irrigated with water contaminated by liquid effluents; shoreline, boating, and swimming activities; drinking potentially contaminated water; and direct irradiation from within the plant itself. Calculations for most pathways are limited to a radius of 80 km (50 miles). Beyond 80 km, the doses to individuals are smaller than 0.1 mrem/year, which is far below the average natural-background dose of 300 mrem/year.
For this study, effluent and population dose information was collected from a series of documents that have resulted from ongoing NRC programs. Source-term data (normal effluent releases from nuclear power plants) are assembled annually at Brookhaven National Laboratory (NUREG/CR-2907), and calculations of radiation dose to the public are performed at Pacific Northwest Laboratory. Documentation is given in a series of reports titled Population Dose Commitments Due to Radioactive Releases from Nuclear Power Plant Sites (NUREG/CR-2850). The source terms (measured in effluents) are used to estimate dose commitments to those persons assumed to be living in a region between 2 and 80 km (1.2 and 50 miles) from the reactor sites. Atmospheric transport factors (annual average dilution and annual average deposition) were calculated for the region around each site using appropriate meteorological data supplied by either the NRC or the utility. Site-specific parameters other than releases, meteorology, and population were obtained from environmental impact statements or updates in environmental monitoring reports. Parameter values include the total population drinking contaminated water, fish and invertebrate harvest for the region, and dilution factors. For those cases in which site-specific data were not readily available and the particular pathway was not expected to result in a large dose, assumptions intended to be conservative were used to estimate doses. The use of more realistic data should decrease dose estimates in most cases. To this end, each licensee has the opportunity to provide site-specific data. Doses were calculated using models approved by the NRC (NUREG/CR-2850).
18.104.22.168 Risk Estimates from Radiation Exposure
In estimating the health effects resulting from both off-site and occupational radiation exposures as a result of refurbishment of nuclear power facilities, the staff used normal probability coefficients for stochastic effects recommended by the ICRP (ICRP 1991). The coefficients consider the most recent radiobiological and epidemiological information available and are consistent with the United Nations Scientific Committee on the Effects of Atomic Radiation. The coefficients used in this GEIS (Table 3.9) are the same as those recently published by ICRP in connection with a revision of its recommendations (ICRP 1991). Excess hereditary effects are listed separately in this GEIS because radiation-induced effects of this type have not been observed in any human population, as opposed to excess malignancies that have been identified among populations receiving instantaneous and near-uniform exposures in excess of 10 rem. Details regarding the risk of radiation-induced health effects are provided in Appendix E.
|Table 3.9 Nominal probability coefficients used in this generic environmental impact statementa|
aEstimated number of excess effects among 10,000 people receiving 10,000 person-rem. Coefficients are based on "central" or "best" estimates.
Source: ICRP 1991.
22.214.171.124 Baseline Gaseous and Liquid Effluents
Public radiation exposures from gaseous and liquid effluents resulting from refurbishment can be evaluated on the basis of effluent data from the replacement of steam generators and recirculation piping. The projections are based on large refurbishment efforts that have already been performed. Among the past refurbishment efforts, steam generator replacement has been the largest operation at U.S. PWRs. Replacement of the recirculating coolant piping probably represents the largest single effort at BWRs. During the replacement of steam generators and recirculation piping, releases of effluents have taken place under controlled conditions and in accordance with ALARA principles. Similar refurbishment efforts that may occur as part of the license renewal process would also take place under controlled conditions and in accordance with ALARA principles.
For the first several plants to replace steam generators, environmental reports were prepared that estimated amounts of radioactivity expected to occur in liquid and gaseous effluents as a result of the repair (NUREG/CR-3540). Actual effluent measurements were performed in several cases. The values are presented in Table 3.10, along with a summary of the same actual effluent types from BWRs and PWRs for 1986. It should be noted that steam generator repairs took less than a year, typically 6 to 9 months. The 1986 data are used because they represent a mid-level year between the early, post-Three Mile Island (TMI) backfitting and the more recent years that reflect a protracted emphasis on ALARA as well as the completion of the post-TMI backfits. The expected or measured releases from the refurbishments were also compared with (1) the normal operational effluents as predicted in the final environmental statements for the affected plants and (2) measured releases from the normal operation of these few reactors and for all reactors for 1986 as reported in NUREG/CR-2907. For each effluent type, when effluents associated with steam generator replacement are compared with those for normal operation as predicted in the final environmental statements, measured at the specific sites or measured at all LWR sites, they are found to be of the same order as or much less than effluents from normal operation for a year. The replacement of a steam generator does not change a plant's technical specifications relative to accident risk; thus, based on 10 CFR Part 50.59 an environmental assessment is not required. This point, coupled with past experience resulting in small environmental releases associated with steam generator changeouts, suggests that National Environmental Policy Act documents are not likely for future steam generator replacements.
|Table 3.10 Radioactive effluent source terms for steam generator replacements compared with typical 1986 effluent data for boiling-water reactors (BWRs) and pressurized-water reactors (PWRs)|
|Radioactive effluent||Surrya measurement
|Turkey Pointa measurement
|Point Beachb estimate
|H. B. Robinsonc estimate
|Unit 1||Unit 2||Unit 3||Unit 4|
|Noble gases||510||101||--||875||Negligible||140||53%, 1000e||57%, 1000||25%, 1000||23%, 1000|
|Iodine||0.0033||0.69||--||0.039||0.000007||0.00004||63%, 0.01||26%, 0.01||42%, 0.01g||49%, 0.01g|
|Particulates||0.0027||0.0013||0.00021||0.0012||0.00015||0.00009||63%, 0.01||26%, 0.01||--||--|
|Mixed fission and activitation products (excluding tritium)||0.52||0.26||0.12||0.078||0.23||0.0013||50%, 0.1||30%, 1.0||47%, 0.1||39%, 1.0|
|Tritium||8.5f||--||--||47||125||14||26%, 10||85%, 100||37%, 100||90%, 100|
dAdapted from NUREG/CR-2907.
eRead as: 53% of the BWR nuclear power reactor sites released annually at least 1000 Ci of noble gases per reactor unit in 1986 (1 Ci = 3.7 x 1010 Bq).
fEstimated value from NUREG-0692.
gData for the most recent years reported combine iodine and particulates.
Documents comparable to NUREG/CR-2907 estimating anticipated releases to the environment were not identified for BWR recirculation piping replacement, reflecting relatively less concern on the staff's part for effluents from recirculation piping replacement compared with initial concern for steam generator replacement. However, data of a similar nature are obtained from the two series of NRC summary documents, Radioactive Materials Released from Nuclear Power Plants (NUREG/CR-2907) and Population Dose Commitments Due to Radioactive Releases from Nuclear Power Plant Sites (NUREG/CR-2850). Annual release and dose commitment information for five reactor sites--Cooper, Monticello, Nine Mile Point-1, Peach Bottom-2, and Vermont Yankee--is presented in Table 3.11. Data presented in Table 3.11 demonstrate that releases of radioactive materials during recirculation piping replacement and consequent radiation doses to the public are similar to or less than those resulting from normal operation of the same plants. (Note that Peach Bottom Units 2 and 3 are reported together.) Releases from Peach Bottom Units 2 and 3 are typically larger than those at many other BWRs, although the releases still result in very small radiation doses to the public. This site has the largest releases during recirculation piping replacement. Given that data of Table 3.11 are representative of early technology for the recirculation piping replacement procedure, similar procedures during refurbishment of BWRs related to license renewal are not anticipated to result in significantly larger effluent releases or consequent radiation doses to the public.
Trends for dose reduction in the LWR industry (as seen in Table 4.6) suggest that dose reduction measures are working.
126.96.36.199 Dose to the Public from Radiological Effluents
Section 2.6 and Appendix B consider the scenario and types of potential refurbishment activities that may take place for license renewal. Only the period of major refurbishment is examined here because the potential for release of radioactive materials is greater for the single major refurbishment than for refurbishment in each of the four current term outages.
Detailed estimates of effluents associated with major refurbishment are not available at this time; however, there is a significant data base upon which to assess expected impacts. Major refurbishment efforts have taken place at PWRs and BWRs; associated data are presented in Tables 3.10 and 3.11. Within these tables, it is seen that effluents and dose impacts do not differ significantly from normal operation when a major refurbishment is performed. It is expected that, during the 9-month outage, a greater amount of work will be performed and some of the effluents, especially atmospheric particulates and possibly some liquid effluents associated with decontamination, may be slightly greater than were found during the steam generator changeouts or recirculation piping replacements. However, because of their origins (other effluents, for example), the noble gases and tritium gaseous emissions, which constitute the largest proportion of the total body dose from gaseous effluents to the maximally exposed individual, are not expected to increase beyond levels experienced for the already performed major refurbishments.
|Table 3.11 Radioactive effluent releases and radiation doses to the public for boiling-water reactors (BWRs) that have had recirculation piping replaced.|
|Liquid releases||Air releases|
|Year||Net electrical energy (106 MWh)||Total outage dates||Tritium
|Fission and activation products (Ci)||Population dose
|I-131 and particulates
|Fission and activation products
|Nine Mile Point 1|
|Peach Bottom 2c|
bNine Mile Point--2 began operation in 1987. Radioactive releases are reported separately for units 1 and 2 in NUREG/CR-2907; doses reported are combined for units 1 and 2 in NUREG/CR-2850.
cData for Peach Bottom includes units 2 and 3.
Sources: NUREG/CR-4494; NUREG/CR-2907-V8; NUREG/CR-2850.
The resultant potential impacts on members of the public can be gauged with respect to impacts already experienced. Data tabulated in Appendix E on the maximally exposed individual from routine airborne emissions suggest that from 1985 through 1987, approximately 5 percent of the 47 plants for which data have been tabulated caused in any year annual total body doses of 1 mrem or greater, and approximately 10 percent caused thyroid doses of 1 mrem or greater. Because effluents and doses during periods of accomplished major refurbishment (Tables 3.10 and 3.11) have not been seen to differ significantly from normal operation, gaseous effluents and liquid discharges occurring during the 9-month refurbishment are not expected to result in maximum individual doses exceeding the design objectives of Appendix I to 10 CFR Part 50 or the allowable EPA limits of 40 CFR Part 190.
Within an 80-km (50-mile) radius, the average individual dose, considering all licensed LWRs, for 1985 to 1987 was between 0.001 and 0.002 mrem. If these values were increased a few percent, they would still be small. The average collective dose within an 80-km (50-mile) radius is between 1.0 and 2.0 person-rem (NUREG/CR-2850). For the assumed 9-month period of major refurbishment, these values might be raised slightly. In order to provide a point of comparison, the NCRP estimates that the effective dose equivalent from natural background sources to an individual in the United States is approximately 300 mrem annually. Typically, about 1 million persons are within an 80-km (50-mile) radius of a nuclear facility; this population will annually collect approximately 300,000 person-rem from natural background radiation.
Radiobiologists and epidemiologists generally agree that the collective dose to a population would have to be much larger than current doses from nuclear power plants before health effects would become a realistic concern. In its 1988 report (paragraph 251), the United Nations Scientific Committee on the Effects of Atomic Radiation stated:
The product of risk coefficients appropriate for individual risk and the relevant collective dose will give the expected number of cancer deaths in the exposed population, provided that the collective dose is at least of the order of 100 man-Sv (10,000 person-rem). If the collective dose is only a few man-Sv, the most likely outcome is zero deaths.
In BEIR-V (1990) (p. 181), the National Academy of Sciences' Advisory Committee on the Biological Effects of Ionizing Radiation stated:
Moreover, epidemiologic data cannot rigorously exclude the existence of the threshold in the millisievert [1 mSv is equivalent to 100 mrem] dose range. Thus, the possibility that there may be no risks from exposures comparable to external natural background radiation cannot be ruled out. At such low doses and dose rates, it must be acknowledged that the lower limit on the range of uncertainty in the risk estimates extends to zero.
In the event that small annual radiation doses (i.e., 0.001 mrem/year) contribute to cancer risks, the "best estimate" of cancer risk would be 5 x 10-10/year. EPA considers that a risk level of 1 x 10-6 to the public provides an ample margin of safety and is an acceptable risk.
188.8.131.52 Dose to the Public from On-Site Storage of Radioactive Materials
Steam generator assemblies, recirculation piping, and other large assemblies may be stored on- site in shielded buildings. Potential doses from such storage can be estimated from information gained by previous experience with steam generators. Each steam generator will contain approximately 300 Ci of fixed gamma emitters at the time it is removed from the containment (NUREG-1003). In past steam generator replacements, storage buildings that housed the removed steam generators and associated equipment provided sufficient shielding to limit the dose rate to less than 1 mrem/h outside the building. Shielding of a similar nature for buildings that may contain more than one steam generator or recirculation piping is anticipated for future refurbishment efforts because of the need to minimize occupational doses. If one of these buildings were 275 m (1500 ft), a typical distance, from the nearest site boundary, the estimated additional dose rate at the site boundary would be less than 0.00001 mrem/h from on-site storage of the steam generators and other equipment. An individual who lived at this location for 1 year would receive less than 0.1 mrem from this source. This dose rate would decrease rapidly during the first 2 years of storage because short-lived radionuclides would decay; thereafter, the dose would decrease by a factor of two every 5 years as the remaining 60Co decayed. The staff concludes that radiation doses to the public from on-site storage of steam generators, recirculation piping, and other assemblies removed during refurbishment would be very small and insignificant.
184.108.40.206 Cumulative Impacts
A perspective on the addition of a radiation burden to members of the U.S. population can be gained from the data presented in Table 3.12. A total average annual effective dose equivalent of 360 mrem/year to members of the U.S. population is contributed by two primary sources: naturally occurring radiation and artificial sources (including human enhancement of natural sources) of radiation. Natural radiation sources other than radon result in 27 percent of the typical radiation dose received. The larger source of radiation dose (55 percent) is from radon, particularly because of homes and other buildings that entrap radon and significantly enhance its dose contribution over open-air living. The remaining 18 percent of the average annual effective dose equivalent consists of radiation from medical procedures (x-ray diagnosis, 11 percent, and nuclear medicine, 4 percent) and from consumer products (3 percent). For consumer products, the chief contributor is radon in domestic water supplies, building materials, mining, and agricultural products, as well as coal burning. (Smokers are additionally exposed to the natural radionuclide 210Po in tobacco, resulting in the irradiation of a small region of the bronchial epithelium to up to 16,000 mrem/year. Tobacco products are the dominant contributor to individual body organ doses, but the conversion of the organ dose to effective dose equivalent is too uncertain for NCRP to include it in its tables. However, NCRP used a weighting factor of 0.08 and estimated effective dose equivalents to an average smoker of 1,300 mrem/year and to an average member of the U.S. population of 280 mrem/year (NCRP, Report No. 95, 1987). Radiation exposures from occupational activities, nuclear fuel cycle, and miscellaneous environmental sources (including nuclear weapons testing fallout) contribute very insignificantly to the total average effective dose equivalent.
|Table 3.12.Average annual effective dose equivalent of ionizing radiations to a member of the U.S. population|
|Effective dose equivalent|
|Source||mrem||Percent of total|
|Radon (human enhanced)||200||55|
|Nuclear fuel cycle||< 1.0||< 0.03|
|Fallout||< 1.0||< 0.03|
|Miscellaneous||< 1.0||< 0.03|
|Total natural and artificial||360||100|
Source: Adapted from NCRP (1987).
Activities at nuclear power stations can be considered to contribute to the cumulative radiation burden. During the major period of refurbishment, radiation dose to members of the public within a 50-mile radius are not expected to change significantly from the current-term conditions which were between 0.001 and 0.002 mrem/year during 1985-1987, and even lower in the most recent reporting year. In 1990, the average dose was 0.0005 mrem/year. During refurbishment, the average dose to the public will remain very small, probably unchanged from current operation which, according to the most recent year analyzed, is less than 0.001 mrem/year. Therefore, cumulative impacts of radiation dose to members of the public should remain a very small part (less than 0.0003 percent) of the ionizing radiation dose to an average member of the U.S. population.
Radiation exposures to the public have been examined for potential mitigation, based on findings of impacts during the refurbishment effort. Adequate mitigation is already in place and properly functioning: the preceding sections demonstrate that public radiation doses have been steadily decreasing over nearly two decades.
The basis for current mitigation is found in the Code of Federal Regulations governing nuclear power plants. For example, in 10 CFR Part 20.1101 (radiation protection programs), specific requirements are detailed:
|(a)||Each licensee shall develop, document, and implement a radiation protection program commensurate with the scope and extent of licensed activities and sufficient to ensure compliance with the provisions of this part (see Section 20.2102 for recordkeeping requirements relating to these programs).|
|(b)||The licensee shall use, to the extent practicable, procedures and engineering controls based upon sound radiation protection principles to achieve occupational doses and doses to members of the public that are ALARA.|
|(c)||The licensee shall periodically (at least annually) review the radiation protection program content and implementation.|
Regulations under which licensees of nuclear power plants operate explicitly require that attention be made to reducing public radiation exposures. Evidence is provided in Tables 3.10 and 3.11 as well as in the text of Sections 2 and 3 and in Appendices B and E to demonstrate that major refurbishment efforts taken during the current term of operation have operated under ALARA principles. Refurbishment activities that will take place in anticipation of license renewal can also be expected to comply with federal regulations in minimizing radiation dose.
Because of the existing federal regulations requiring operation under ALARA principles, and the historical record demonstrating that the regulations are being followed and are effective, ample evidence is provided that adequate mitigation for radiation exposure is already in place for major refurbishment activities and additional mitigation requirements are not warranted.
Off-site doses to the public attributable to refurbishment have been examined for both the maximally exposed individual and the typical or average individual. Because the focus of the analysis is on annual dose, only the results based on the assumed 9-month refurbishment outage were examined. In each instance, impacts were found to be small. To date, effluents and doses during periods of major refurbishments have not been seen to differ significantly from normal operation. Consequently, gaseous effluents and liquid discharges occurring during the 9-month refurbishment are not expected to result in maximum individual doses exceeding the design objectives of Appendix I to 10 CFR Part 50 or the allowable EPA limits of 40 CFR Part 190. Both the average individual dose and the 80-km (50-mile) radius collective doses will remain approximately 100,000 times less than the dose from natural background radiation. The evaluation of off-site radiation doses attributable to refurbishment determined that their significance is small for all nuclear plants. Radiation impacts to the public are considered to be of small significance because public exposures are within regulatory limits. It should also be noted that the estimated cancer risk is to the average member of the public is much less than 1 x 10-6. Because current mitigation practices are properly functioning, cumulative impacts would not be significantly increased by refurbishment. Because current mitigation practices have resulted in declining public radiation doses for nearly two decades, additional mitigation is not warranted. The impact on human health is a Category 1 issue.
3.8.2 Occupational Dose
To determine the significance of the estimated occupational dose for refurbishment, the staff has compared dose projections for refurbishment with the historical (baseline) doses experienced at PWRs and BWRs. The dose estimates are based on detailed investigations of major refurbishment or replacement activities. Projected doses were used as the basis for estimates of cancer and genetic risk. Finally, the staff has compared the estimated risk to nuclear power plant workers with the risks to those workers from exposure to naturally occurring radiation and with published risks for other occupations. For the purpose of assessing radiological impacts to workers, the Commission has concluded that impacts are of small significance if doses and releases do not exceed permissible levels in the Commission's regulations. The standards for acceptable dose limits are given in 10 CFR Part 20.
Throughout the nuclear power industry, construction-type activities have continued at each operating plant but at greatly reduced levels compared with the original plant construction. These construction activities have included a broad range of plant modifications and additions made in response to a number of NRC requirements and industry initiatives, including post-TMI upgrades, radioactive waste system modifications, and spent fuel storage upgrades. In addition, several nuclear power plants have experienced major refurbishment efforts such as PWR steam generator replacement and the replacement of coolant recirculation piping in BWRs. These activities had significant potential for occupational exposure. Thus, occupational exposure histories accumulated to date are reflective of normal operation plus modifications and additions to existing systems. This information forms the basis for the evaluation of occupational doses resulting from refurbishment associated with license renewal.
220.127.116.11 Baseline Occupational Exposure
Table 3.13 shows the occupational dose history for PWRs and BWRs. Average collective occupational dose information and average annual individual worker doses are presented for those plants operating between 1974 and 1992. The year 1974 was chosen as a starting date because the dose data for years before 1974 are primarily from reactors with average rated capacities below 500 MW(e). Since the early 1980s, when the majority of post-TMI plant modifications were completed, there has been a decreasing trend in the average collective occupational dose. The average collective doses, however, are based on widely varying yearly doses. For example, between 1974 and 1992, annual collective doses for operating PWRs have ranged from 13 to 3223 person-rem; for operating BWRs, the figures range from 53 to 4083 person-rem. A decreasing trend in the highest annual collective dose is somewhat apparent, as is that for the average collective dose. In addition to decreases in collective dose, the average annual dose per nuclear plant worker has been reduced during this period from somewhat more than 0.8 rem to about 0.3 rem for BWRs and from around 0.7 rem to less than 0.3 rem for PWRs. A breakdown of the number of individual workers receiving doses in different ranges for 1992 is provided in Table E.8. These data demonstrate that 94 percent of plant radiation workers received less than 1 rem, and no worker received more than 4 rem. Overall data presented in Table 3.13 and in Appendix E provide ample evidence that doses to nearly all radiation workers are far below the worker dose limit established by 10 CFR Part 20 and that the continuing efforts to maintain doses at ALARA levels have been successful. A portion of the total work force can be defined as "transient." These individuals are usually employed for special functions and may be employed at multiple reactor sites during a given year. Data for individual reactors described earlier include these people, but only for each power plant. Thus some people are counted more than once and some people receive greater annual doses than are reported by individual plants. In 1993 there were approximately 13,000 of these people (NUREG-0713 1995). Over the years, doses to transient workers have been decreasing in the same way as doses to more permanent workers at nuclear power plants, going from an average of 1.04 rem in 1984 to 0.49 rem in 1993 (NUREG-0713 1995). In 1993 four transient workers received whole body doses between 4 and 5 rem, and no individuals received more than 5 rem (NUREG-0713 1995).
|Table 3.13 Annual average occupational dose for U.S. licensed light-water reactors|
|Reported collective occupational dose (person-rem)|
|BWRa||PWRb||Annual average whole-body dose (rem)|
aBWR = boiling-water reactor.
bPWR = pressurized-water reactor.
The wide range of annual collective doses experienced at LWRs in the United States results from a number of factors such as the reactor design, the amount of required maintenance, and the amount of reactor operations and in-plant surveillance. Because these factors can vary widely and unpredictably, it is impossible to determine in advance a specific year-to-year annual occupational radiation dose for a particular plant throughout its operating lifetime. On occasion, there may be a need for relatively high collective occupational doses compared with the average annual collective dose, even at plants with radiation protection programs designed to ensure that occupational doses will be kept to ALARA levels.
18.104.22.168 Projected Doses During Refurbishment
Many nuclear power plant operators have accrued considerable experience with the types of refurbishment activities that will be associated with license renewal. On the average, utilities have spent approximately $140 million per plant in modifications, and experience in retrofitting and modifying operating reactors has been gained. The level of effort required to support large construction activities such as a steam generator replacement has involved, for example, from 200,000 to 900,000 person-hours. The duration of shutdown has lasted from about 8 months to 2 years. Less complex modifications have required fewer person-hours and less plant downtime. Personnel who perform the modifications have often worked in relatively high radiation fields. Component surface exposure rates range from a few hundred mrem per hour to several rem per hour. The resulting cumulative radiation exposure to the work force has ranged from about 300 to 3500 person-rem for large, complex modifications and from 2 to 100 person-rem for smaller ones.
Throughout the process of plant modifications, it has been routine industrial practice to conduct ALARA reviews and studies on projects that may involve significant personnel exposures. Such evaluations are intended to assist the engineering of systems or implement radiological work practices that will reduce personnel exposures. Nonetheless, it is anticipated that each refurbishment program will result in occupational radiation doses in addition to those expected from normal operation during that time period.
Two scenarios were developed to estimate the occupational radiation doses caused by refurbishment activities: (1) a typical scenario that is expected in most situations and (2) a conservative scenario that is intended to capture additional work that might occur for those outlier plants whose impacts will be considerably greater than what is typical of the reactor population as a whole (see Section 2.6 and Appendix B). Care was taken to ensure that the dose estimates were conservative. The scenarios include work done in support of refurbishment during four current-term outages plus a single period of major refurbishment. Dose estimates for activities during each of the four current-term refurbishment outages are 11 and 10 person-rem for PWRs and BWRs respectively for the typical case and 200 and 191 person-rem respectively for the conservative case (see Tables 2.8 and 2.11). Dose estimates for the assumed single periods of major refurbishment are 79 and 153 person-rem for PWRs and BWRs respectively for the typical case and 1380 and 1561 for person-rem respectively for the conservative case.
22.214.171.124 Analysis of Occupational Exposures
According to the scenario developed in Appendix B, refurbishment efforts expended during the current licensing term are to take place during four outages plus a single large outage devoted to major items. Doses to power plant workers will, accordingly, take place during five time periods. Under the conservative scenario, the projected 200 to 191 person-rem for each of the four current term outages could increase the average annual collective dose during that period (based on 1992 numbers; see Table 3.13) from the range of 219 to 360 person-rem to the range of 419 to 551 person-rem for PWRs and BWRs respectively. These doses are similar to the average collective dose that was experienced by all LWRs during the second half of the 1980s. Under the typical scenario, the occupational doses would increase by less than 5 percent for both reactor types.
The single large outage effort in the conservative refurbishment scenario is estimated to result in a single-year increase in collective occupational dose (based on 1992 numbers) from 219 to 1599 person-rem for PWRs and from 360 to 1921 person-rem for BWRs. These levels are above the average of all reactors for any given year during the 1980s but are well below the levels for the highest single years for most BWRs and some PWRs (NUREG-0713). Thus the anticipated collective occupational doses attributable to refurbishment under the conservative scenario are in the range of doses already experienced by a large portion of the nuclear power plant industry. Under the typical scenario, the single large outage would add less than 7 percent to the current annual occupational doses.
During the large refurbishment outage, even in the conservative case, it is anticipated that average individual occupational doses will be maintained at acceptable levels. Experience during the early 1980s, when considerable backfitting was being performed within the industry, has shown that average worker doses could be kept to about 0.8 rem (NUREG-0713). Average worker doses are now in the 0.3-0.4 rem range. Because many activities in the 1980s were the same or similar to those expected to be performed in the refurbishment related to license renewal, it is estimated that such work can be performed while maintaining radiation protection to the degree achieved during the 1980s. On that basis, the NRC staff has compared the risks associated with the range of 0.4-0.8 rem to published risks associated with other occupations (Table 3.14). In this table, only nuclear plant workers are given the added chronic risk resulting from occupational exposures. Thus the risk for this category of workers is inflated by the theoretical calculations. There are three entries in Table 3.14 for nuclear power plant workers: using an annual average dose of 0.8 rem in conjunction with the "best estimate" cancer risk estimator; using an annual average dose of 0.4 rem in conjunction with the "best estimate" cancer risk estimator; and using the lower limit risk cancer estimator for both 0.8 and 0.4 rem.
During the 1980s, the average annual worker doses were reduced by a factor of two, from 0.8 to 0.4 rem (Table 3.13). Part of the reduction has resulted from the completion of backfitting work and part has resulted from improvements in radiation protection (ALARA) programs. The precise average annual worker doses that will accompany refurbishment are not known at present but are anticipated to be between 0.8 and 0.4 rem. This dose range puts nuclear power plant workers in the mid-range of job-related mortality incidence (Table 3.14). The actual cancer incidence as a result of radiation exposures at such low rates (i.e., two to three times natural background radiation) may be zero (NAS 1990). As a consequence, the actual occupational risk for nuclear plant workers may be in the lower part of the mortality incidence table. On the basis of these comparisons, the staff concludes that the risk to nuclear plant workers from refurbishment efforts associated with license renewal is comparable to the risks associated with other occupations.
The staff has examined the cumulative effects of occupational exposures during refurbishment activities under the conservative scenario. These effects are based on the dose estimate for BWRs (Appendix B) as an upper bound. A total of 2000-4000 persons are expected to compose the refurbishment work force if average annual individual doses are maintained at 0.4 to 0.8 rem. The risk of potentially fatal cancers in the exposed refurbishment work force population at a typical site and the risk of potential genetic disorders in all future generations of this refurbishment work force are estimated as follows: multiplying the estimated cumulative dose of 2325 person-rem (4 x 191 person-rem + 1561 person-rem) by the limit of the risk coefficients described earlier (Section 126.96.36.199 and Table 3.9), the staff estimates that between zero and one additional cancer death could occur in the total exposed refurbishment population for a given power plant. The magnitude of this risk estimate can be understood by comparing it with the current incidence of cancer deaths. Multiplying the estimated exposed worker population of 2000 to 4000 persons by the current incidence of actual cancer fatalities (20 percent), about 400 to 800 cancer deaths are expected in this population from causes other than occupational radiation exposure (American Cancer Society 1994).
The risk estimate of 0.1 genetic disorder to the progeny of the exposed refurbishment work-force population is roughly 5 million times less than the risk estimates of natural incidence of actual genetic ill health of about 500,000 expected for the same progeny. Because the risk is borne by the progeny of the entire population, it is thus properly considered as part of the risk to the general public. BEIR-III (1980) indicates that the mean persistence of the two major types of genetic disorders are about five generations and ten generations respectively. The risk of potential genetic disorders from refurbishment is conservatively compared with the risk of actual genetic ill health in the first five generations, rather than the first ten generations. Multiplying an assumed population of 1 million persons in the vicinity of the plant by the current incidence of actual genetic ill health in each generation (11 percent) yields an estimate that about 500,000 genetic abnormalities are expected in the first five generations of this population.
|Table 3.14 Incidence of job-related mortalitiesa|
|Occupational group||Mortality rates
(premature deaths per 105 person-years)
|Underground metal minersb||~1300|
|Nuclear-plant workers (early 1980s)d||44|
|Agriculture, forestry, and fisheriesc||35|
|Nuclear-plant workers (1992)e||24|
|Transportation and public utilitiesc||20|
|Wholesale and retail tradec||5|
aMortality incidences in this table do not include
occupational diseases except for the hypothetical cancer incidence in
nuclear plant workers.
bU.S. Department of Health, Education, and Welfare 1972.
cAccident Facts 1994 Edition, National Safety Council.
dThe nuclear-plant worker's risk is equal to the sum of the radiation-related risk and the non-radiation-related risk. The estimated occupational risk associated with an average radiation dose of 0.8 rem is about 32 potential premature deaths per 105 person-years resulting from cancer, based on the ICRP 60 "best estimate" risk estimator of 4 x 10-4/rem (ICRP 1991). The average non-radiation-related risk for seven U.S. electrical utilities during the 1970-79 period was about 12 actual premature deaths per 105 person-years, as shown in Figure 5 of Wilson and Koehl. (Note that the estimate of 32 radiation-related premature cancer deaths describes potential risk rather than an observed statistic. The lower confidence limit is zero.)
eThe average worker dose in 1992 was approximately 0.3 rem. Using the "best estimate" risk estimator, about 12 premature deaths per 105 person-years are expected. Also, 12 actual premature deaths are caused by nonradiological causes typical of electrical utilities (see footnote c). The lower confidence limit is zero.
fUsing the lower confidence limit for the risk estimate, no deaths from occupational radiation exposures are anticipated and the mortality incidence results totally from nonradiological causes typical of electrical utilities.
Source: Adapted from Wilson and Koehl (1980).
188.8.131.52 Cumulative Impacts
Currently, occupational radiation doses are on the order of 0.4 rem/year in addition to the 0.36 rem/year received by the typical U.S. resident. The cumulative impact of the estimated exposures due to refurbishment would be to increase average occupational radiation exposures for those involved from 0.76 rem to 0.79 rem for the year that includes the 9-month refurbishment period.
Occupational doses from refurbishment activities associated with license renewal (including current-term outages and the assumed single large outage) are estimated to be less than 1 percent of regulatory dose limits. The average individual exposures for refurbishment are expected to remain roughly the same as they have been during the last decade, within the middle zone of the occupations examined. The "best estimate" cancer risk due to refurbishment, 1 x 10-5, is less than 10 percent of the ongoing annual occupational risk of 1.6 x 10-4 and less than 1 percent of the lifetime accumulation of occupational risk of 4.8 x 10-3. Occupational radiation exposure during refurbishment meets the standard of small significance. Because the ALARA program continues to reduce occupational doses, no additional mitigation program is warranted. This is a Category 1 issue.
3.9 Threatened and Endangered Species
Potential impacts of refurbishment on federal- or state-listed threatened and endangered species, and species proposed to be listed as threatened or endangered, cannot be assessed generically because the status of many species is being reviewed and it is impossible to know what species that are threatened with extinction may be identified that could be affected by refurbishment activities. In accordance with the Endangered Species Act of 1973 (Pub. L. 93-205), the appropriate federal agency (either the U.S. Fish and Wildlife Service or the National Marine Fisheries Service) must be consulted about the presence of threatened or endangered species. At that time, it will be determined whether such species could be affected by refurbishment activities and whether formal consultation will be required to address the impacts. Each state should be consulted about its own procedures for considering impacts to state-listed species. Because compliance with the Endangered Species Act cannot be assessed without site-specific consideration of potential effects on threatened and endangered species, it is not possible to determine generically the significance of potential impacts to threatened and endangered species. This is a Category 2 issue.
3.10 Summary of Impacts of Refurbishment
The following conclusions have been drawn with regard to the impacts of refurbishment.
On-Site Land Use
- On-site land use impacts are expected to be of small significance at all sites. Temporary disturbance of land may be mitigated by restoration to its original condition after refurbishment. This is a Category 1 issue.
- Nuclear power plant atmospheric emissions would either remain constant during refurbishment or decrease if the plant were partially or totally shut down. Small quantities of fugitive dust and gaseous exhaust emissions from motorized equipment operation during construction and refurbishment would temporarily increase ambient concentrations of particulate matter and gaseous pollutants in the vicinity of the activity but would not be expected to measurably affect ambient concentrations of regulated pollutants off-site. Additional exhaust emissions from the vehicles of up to 2300 personnel could be cause for some concern in geographical areas of poor or marginal air quality, but a general conclusion about the significance of the potential impact cannot be drawn without considering the compliance status of each site and the numbers of workers to be employed during the outage. This is a Category 2 issue.
Surface Water Quality and Use
- Proven erosion control measures such as best management practices are expected to be implemented at all plants and to minimize impacts to local water quality from runoff in disturbed areas. Consequently, impacts of refurbishment on surface water quality are expected to be of small significance at all plants. Because the effects of refurbishment are considered to be of small significance and potential mitigation measures are likely to be costly, the staff does not consider implementation of mitigation measures beyond best management practices to be warranted. This is a Category 1 issue.
- Additional water requirements during construction and refurbishment would be a small fraction of cooling water requirements of the operating power plant. If the plant is partially or totally shut down, cooling water use would decline. Water use during refurbishment is expected to have impacts of small significance on the local water supply. The only potential mitigation for any increase in water consumption would be to acquire the additional water from some other source. However, because this approach would provide very little, if any, environmental benefit and would be costly, the staff does not consider implementation of additional mitigation to be warranted. This is a Category 1 issue.
- Deep excavations and site dewatering would not be required during refurbishment. Consequently, the impacts of refurbishment on groundwater would be of small significance at all sites. No additional mitigation measures would be warranted because there would be no adverse impacts to mitigate. This is a Category 1 issue.
- Effluent discharges from the cooling system of a nuclear power plant would either remain constant during refurbishment or decrease if the plant were partially or totally shut down. Effects of changes in water withdrawals and discharges during refurbishment would be of small significance. No additional mitigation measures beyond those implemented during the current license term would be warranted because there would be no adverse impacts to mitigate. This is a Category 1 issue.
- The small on-site change in land use associated with refurbishment and construction could disturb or eliminate a small area of terrestrial habitat [up to 4 ha (10 acres)]. The significance of the loss of habitat depends on the importance of the plant or animal species that are displaced and on the availability of nearby replacement habitat. Impacts would be potentially significant only if they involved wetlands, staging or resting areas for large numbers of waterfowl, rookeries, restricted wintering areas for wildlife, communal roost sites, strutting or breeding grounds for gallinaceous birds, or rare plant community types. Because ecological impacts cannot be determined without considering site- and project-specific details, the potential significance of those impacts cannot be determined generically. This is a Category 2 issue.
- Because of refurbishment-related population increases, impacts on housing could be of moderate or large significance at sites located in rural and remote areas, at sites located in areas that have experienced extremely slow population growth (and thus slow or no growth in housing), or where growth control measures that limit housing development are in existence of have recently been lifted. This is a Category 2 issue.
- Tax impacts, which involve small to moderate increases in the direct and indirect tax revenues paid to local jurisdictions, are considered beneficial in all cases.
- In the area of public services, in-migrating workers could induce impacts of small to large significance to education, with the larger impacts expected to occur in sparsely populated areas. Impacts of small to moderate significance may occur to public utilities at some sites. Transportation impacts could be of large significance at some sites. These socioeconomic issues are Category 2.
- The impacts of refurbishment on other public services (public safety, social services, and tourism and recreation) are expected to be of small significance at all sites. No additional mitigation measures beyond those implemented during the current license term would be warranted because mitigation would be costly and the benefits would be small. These are Category 1 issues.
- In-migrating workers could induce impacts of small to moderate significance to off-site land use, and the larger impacts are expected to occur in sparsely populated areas. This is a Category 2 issue.
- Based on the findings at the case study sites, refurbishment-related economic effects would range from small benefits to moderate benefits at all nuclear power plant sites. No adverse effects to economic structure would result from refurbishment-related employment.
- Site-specific identification of historic and archaeological resources and determination of impacts to them must occur during the consultation process with the SHPO as mandated by the National Historic Preservation Act. Impacts to historic resources could be large if the SHPO determines that significant historic resources would be disturbed or their historic character would be altered by plant refurbishment activities. The significance of potential impacts to historic and archaeological resources cannot be determined generically. This is a Category 2 issue.
- The impact on aesthetic resources is found to be of small significance at all sites. Because there will be no readily noticeable visual intrusion, consideration of mitigation is not warranted. This is a Category 1 issue.
- Radiation impacts to the public are considered to be of small significance because public exposures are within regulatory limits. Also, the estimated cancer risk to the average member of the public is much less than 1 x 10-6. Because current mitigation practices have resulted in declining public radiation doses for nearly two decades, additional mitigation is not warranted. The impact on human health is a Category 1 issue.
- Occupational radiation exposure during refurbishment meets the standard of small significance. Because the ALARA program continues to reduce occupational doses, no additional mitigation program is warranted. This is a Category 1 issue.
Threatened and Endangered Species
- The significance of potential impacts to threatened and endangered species cannot be determined generically because compliance with the Endangered Species Act cannot be assessed without site-specific consideration of potential effects on threatened and endangered species. This is a Category 2 issue.
- The PWR conservative work force number used in this analysis is taken from a work force estimate provided by Science and Engineering Associates, Inc. (SEA), that differs slightly from SEA's work force estimate discussed in Chapter 2 and Appendix B. The slight difference would not affect the conclusions.
- The BWR conservative and typical work force numbers used in this analysis are taken from a work force estimate provided by Science and Engineering Associates, Inc. (SEA), that differs slightly from SEA's work force estimate discussed in Chapter 2 and Appendix B. The slight difference would not affect the conclusions.
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