ML20009C652
| ML20009C652 | |
| Person / Time | |
|---|---|
| Site: | Bailly |
| Issue date: | 07/17/1981 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20009C648 | List: |
| References | |
| NUDOCS 8107210317 | |
| Download: ML20009C652 (10) | |
Text
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ENVIRONMENTAL IMPACT APPRAISAL PREPARED BY THE DIVISION OF LICEN5jNG REGARDING THE EXTENSION OF CONSTRUCTION PERMIT CPPR-104 BAILLY GENERATING STATION, NUCLEAR-1 DOCKET NO.
50-367 ENVIRONMENTAL IMPACT APPRAISAL Description'of Proposed Action In its letter of February 7,1979, the Northern Indiana Public Service Company (NIPSCO or the permittee) subnitted a request to the Nuclear Regulatory Commission (NRC) to extend the date for completion of construction of the Bailly Generating Station, Nuclear-1 (Bailly) to September 1,1985. The latest date specified in the construction permit (CP), CPPR-104, is September 1,1979.
In two subsequent letters dated August 31, 1979, and November 26, 1980, NIPSCO successively amended its request for a construction completion date to December 1,1987, and thence to December 1, 1989. The action proposed by the NRC staff is the issuance of an amendment to the CP extending the latest completion date from September 1,1979 to December 1,1989 The NRC staff's Final Environmental. Statement (FES) regarding the Bailly facility was issued in February 1973 and covered a wide category of environmental issues arising from a prospective decision on tne issuance of a CP for this plant.
In our present appraisal, we evaluate three specific issues originally considered in the FES wnich could be affected by the' proposed extension of tne construction completion date from September 1,1979, to December 1,1989.
The pennittee attributes the delay in completing the Bailly facility to five These separate factors-wnich it claims represent good cause for the delay.
factors have been evaluated by tne NRC staff; we found them to represent good
'.le also found that the latest requested date for completion of construction cause.
reflects a reasonable time. period to construct the Bailly facility based on recent construction experience witn similar facilities and includes sufficient margin for uncertainties in estimating construction tchedules.
8107210317 810717 PDR ADOCK 05000367 G
PDR z
Environmental Impact of the Proposed Action 1.
Socioeconomic Impacts It has been determined from recent experience in building nuclear power plants that more construction workers are required at almost all stages of construction including the period of peak manpower demand, than were required when NIPSCO made its original estimate of the number of construc-tion workers at the Bailly site. This factor has two potentially adverse incremental cffects at the Bailly site; namely, the larger number of workers may impose a demand for services within the nearby communities and could increase the local traffic congestion in the vicinity of the site. These two factors are evaluated in the following sections.
A.
Additional Workers The permittee estimates in its letter of December 18, 1980, that the number of constructions workers at the time of peak labor demand will be 1300 which is 800 larger than the number discussed in the FES.
The permittee expects to hire the additional workers from the construction work force residing in the nearby northurn Indiana and Illinois counties.
These additional 800 workers represent less than five percent of tne total membership of the construction trade union locals fron which these workers will be hired and less than one percent of the total estimated permanent resident construction work force in these counties.
Both of these percentages represent a small demand on the construction worker pool.
Typically, socioeconomic impacts are associated with inmoving construction workers and their families wno impact community infrastructures. Based on tne relatively large, nearby permanent resident construction work force, it is not anticipated that any significant relocation of tnis incremental labor force will occur. Accordingly, the socioeconomic incremental impact cue to the extension of the latest construction completion date is minimal.
B.
Increased Traffic Congestion Witn respect to tne increase in the construction labor force discussed above, additional congestion could readily occur at the intersection of U.S.12 and the east gate entrance to Bethlehem Steel. This particular portion of U.S.12 in the vicinity of tne east gate entrance consists of one lane of traffic going in eacn direction. The left-nand turn lane from the eastbound lane into tne east gate entrance is tne point of maxi-mum congestion. This access to Betnlehem Steel also serves as the entrance for construction workers at the Bailly site. The permittee estimates that at the time of peak -labor demand, there would be 1200 construction workers entering tne Bailly facility through this intersection for the morning shift in aoout 300 venicles in addition to those vehicles used by tne Bethlenem Steel work force.
e Tne National Lakeshore administration plans for traffic diversion discussed in the FES have not been implemented. Accordingly, the increase in automobile traffic during construction due to tne increased number of construction workers entering the Bailly site in the vicinity of the Bethlehem Steel east gate will exacerbate the increase in traffic congestion which was discussed in Section IV.S.4 of the FES. To resolve this potentially adverse impact, the permittee has provided in its letter dated July 3,1981, a commitment to stagger the arrival and departure times of the Bailly construction work force and, thereby, the additional 800 vehicles so as to minimize tne coincident arrivals of the Bethlehem Steel workers and tne Bailly construction workers.
This commitment by NIPSCO to stagger the work shifts of its construction workers represents an improvement over the conditions prev 4ously evaluated in the FES. Accordingly, we conclude that the potentially adverse impact of the additional construction workers at tne Bailly site will be minimized.
2.
Impacts From Continued Construction Dewatering A.
Introduction Dewatering at the Bailly site is required during the early phases of construction. Specifically, construction dewatering of the excavation will be performed while tne safety-related foundation piles are placed, the concrete base mat is poured and the outer walls of the various buildings are built above the " natural" level of the groundwater at the Bailly site. These construction phases should be completed about two to tnree years af ter construction is resumed. This section evaluates the environmental impact, if any, tnat may result from the extension of construction dewatering as a consequence of extending the latest completion date of the Bailly CP.
The FES issued in February 1973 discussed tne matter of construction dewatering and its environmental impacts, especially on tne adjacent Indiana Dunes National Lakeshore. However, NIPSCO proposed in 1974 after issuance of the Bailly CP, to install a slurry wall around the perimeter of the excavation at tne Bailly site. This proposal slightly altered our previous evaluation in the FES. Accordingly, our testimony on construction dewatering at the Bailly site submitted in early 1975 for the hearing on the slurry wall superceded our evaluation in the FES.
Basically, cur testimony on this matter accounted for tne presence of the slurry wall.
Amendment No. I to the Bailly CP was issued in December 1976. This amend-ment autho ized installation of the slurry wall subject to certain specific requirements related to a monitoring and mitigation program for controlling the groundwater levels in the adjacent National Lakeshore. Following installation of the slurry wall in early 1977 and excavation at the site, dewatering of the Sailly excavation has been continuous until the present.
During this perioc of about four years, no adverse impact has been ob-served of fsite..__
B.
Technical and Historical Background The permittee, The U.S. Geologic Survey (U.S.G.S.) and others have undertaken extensive studies of tne soils and the groundwater beneath the site and in the adjacent National Lakeshore. These explorations have generally consisted of holes being drilled, dug, jetted, or driven for building foundation design purposes and for observation or pumping wells. The Geological Survey has punched 11 holes in the Cowles Bog National Landmark and several more in the marshy area around this lanamark. The holes were apparently hand-driven without soil sampling but required personnel and equipment access.
In placing many of tne holes onsite and off, data have been collected which identify the types and vertical extent of different soils. By comparing the material descriptions of tnese soils and the water levels between holes, it is possible to infer the lateral and vertical distribution of tne various soil types.
If tne same types of material were to appear in all holes at about the same general elevations, a high degree of confidence in such inferences could be achieved. However, this is not.the case in the vicinity of the Bailly site whicn is characterized by many dis-continuittes in the soil types.
The soils in the vicinity of tne Bailly site are believed to have been formed by the successive growth, recession and sedimentation of Lake Michigan. The princi-pal mechanism in this cyclical growth pattern is the glaciation that once dominated the region. The many discontinuities noted above are evidenced in the vertical distribution of the various types of materials (stratigraphy) taken in the vicinity of the 3ailly site and confirm the geological interpretation of the depositional patterns.
The materials taken from these borings consist of clays, silts, sands, small gravels and comoinations thereof.
In general, the various soil types exhibit lower values of permeability for the finer materials; low values of permeability results in low velocities for groundwater flows. If finer materials extend over consideraole norizontal distances, tney can effectively limit botn the vertical and horizontal groundwater flows. Deposits which innibit water flow are called aquicludes snile deposits wnich allow water to flow but at a relatively low velocity, are referred to as aquitards. The presence of aquitards and aquicludes is usually determined by comparing water levels from wells finished at different levels above and below such deposits and from pumping tests. Certain characteristics such as the permea-bility and the thickness and tne horizontal extent of similar materials, are also used to determine whether layers of material can be classified as aquifers, aquitards or aquicludes.
t Tne materials in the vicinity of tne Bailly site have been categorized into three basic hydrologic units by the Indiana Department of Conservation; these effectively have Deen adopted by the U.S.G.S.
The upper unconfined unit is referred to as sand unit 1.
A middle confining unit 2 separates the upper unconfined unit i fecm the The lower unit is also referred to as sand by tne U.S.G.S.
lower confined unit 3.
l In studying the water levels and the location and the types of materials from the l
various exploratory holes, a numoer of significant inconsistencies have been i denti fied. First, the lateral extent of the confining unit 2 is not continuous in tnickness; in some places, it appears to be absent.
Second, descriptions
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o of tne various types of materials indicate that there is considerable variability in the hydraulic properties of all three units cited above. Third, where the confining unit 2 does exist, there are indications that it is not totally impermeable. Finally, there are a number of horizontal layers in both units 1 and 3 that have limited lateral extent and have low permeability wnicn can account for localized differences observed in the groundwater pressures.
In the vicinity of the southeast corner of the excavation for the Bailly facility, borings, pumping tests and records of seepage flow rates indicate that the unit 2 confining layer either is not continuous or is ineffective in limiting the up-ward flow of groundwater from unit 3.
The discontinuities in the unit 2 confining layer in the vicinity of the excavation will probably be increased by the three thousand safety-related piles which will be driven through the confining unit 2 in the Bailly excavation as part of the foundation and by the two thousand piles for the turbine building foundation which have already been driven. Water from tne lower unit.3 can be expected to seep into the excavatun in areas where the confining layer does not exist if the total hydraulic head in the unit 2 confining layer is slightly below or exceeds the excavated level.
The permittee has undertaken a number of activities which have altered ground-water movement.
These activities and their gene"al impacts on the groundwater are:
1.
Reactor facility excavation Most facilities for the Bailly plant are to be constructed in an excavated area of aoout 5 acres. This portion of the plant is referred to as the main power block. Excavation has reduced grade levels from about 40 feet above tne mean level of Lake Michigan to about 8 feet above the mean lake level. Further excavation and dewatering of a portion of the existing excavation below lake level will be performed in certain areas sucn as under the reactor building.
Dewatering of tne lower unit 3 sands will be performed as part of the pile place-ment program.' This dewatering of the lowest elevations of tne excavation is to be accomplisned using well points.
ii. Foundation pilings About 150 steel piles have been driven into tne underlying dense sands and clays (unit 3) as part of the indicator pile program. The balance of the 3000 shorter piles will prooably oe driven later this year. Tnese piles will result in a densely-placed subfoundation for all the safety-related reactor building in the main power block.
About two tnousand foundation piles for the turbine building have been driven at the northern end of the excavation.
iii. Slurry and sn6at oile walls A vertical slurry wall has been constructed around most af the excavation to minimize the flow of groundwater into the excavation. A sheet pile wall on the northeast side of the excavation provides a continuous slurry / sheet wall around the excavation. The effectiveness of the bentonite and cement slurry wall and the sheet pile wail has been monitored by use of observation and pumping vells
a'nd by discharge measuring devices inside and outside the excavatit.n.
A sheet pile wall has also been constructed inside the slurry / sheet pile wall around the reactor building excavation, to aid in dewatering.
iv. Ash conds A series of four ash ponds have been used in the past by the permittee to collect the residue from two coal-fired generating plants operated by the per-mittee on the Bailly site. This ash was sluiced from the fossil plants into the ponds and some of the water allowed to drain into the ground. The ash is periodically excavated and removed. The permittee has now initiated measures to seal these ash ponds, thereby preventing the sluice water from entering tne ground. This previous practice of draining some of the sluice water into the permeable sands (unit 1) raised the groundwater level considerably above the " natural" 1evel. Witn the ash ponds sealed, the sluice water will be recycled back to the fossil plant. Records from wells near the tsh ponds indicate tnat since about May 1980, the progress made in sealing the ash ponds'has been effective in that it has substantially reduced 9e groundwater levels, especially in those portions of the National Lakeshore wnicn are immediately adjacent to the ash ponds.
C.
Aquifer Characteristics The characteristics of the material under and surrounding tne Bailly site can be inferred from boring and excavation soil sample data. To do so, however, requires the use of a consistent set of descriptors for materials removed from the borings at different levels and accurate records of water levels. Unfortunately, tne parties collecting the boring and water level data have not always collected the necessary information describing the materials and water levels nor have they used tne same material descriptions when such information was collecteo.
The only locations for which any subsurface data exist are at borings and observa-tions wells made by tne permittee, the U.S.G.S., 3etnlehem Steel and in the 3ailly excavation.
Information describing the characteristics of materials and groundwater free surf ace levels between locations has been developed by comparing available data between locations at which this data exist. The number of locations at wnich data have been collected has increased significantly since the CP hearings in the early 1970's.
In examining all the available data, the NRC staff has concluded tnat the materials underlying the site and tne surrounding area may be classified into layers of varying thickness and types of material. In comparing information from various borings, the RC staff has drawr conclusions relating to the lateral extent of materials of di f ferent types. This same process has been used by the permittee and its consultants and by the U.S.G.S.
In all cases, tne common data have been boring and water level information; all descriptions of the lateral extent of mat-erials of different types have been made by inference.
The size, color, and vertical extent of materials taken from borings and the excavation at tne Bailly site have been interpreted in two Dasically different ways by the U.S.G.S. and by the permi ttee. The U.S.G.S. has concluded that the lateral and vertical extent of tne unit 2 semi-confining layer of fine-grained material is extensive on the Bailly site and in the adjacent lands but may not -
exist or may not be effective under the Cowles Sog National Landmark.
This
- specific cenclusion by the U.S.G.S. appears to be the buis for tne differing views of the permittee and the U.S.G.S.
As a consequence, tne U.S.G.S. has concluded that dewatering during the construction of the Bailly facility could produce a draw-cown in tne water level under Cowles Bog of as much as 0.7 feet. This U.S.G.S.
estimate was derived from its model studies in whicn it assumed tnat the permittee's program for sealing the ash ponds had been completed. The National Park Service, in turn, nas concluded that such a consequence is likely and represents a significant adverse impact.
Alternatively, the permittee and its consultants have interpreted the available data and concluded that the confining layer (unit 2) for the lower aquifer (unit 3) is discontinuous in many locations. Furthermore, the permittee concludes that there are other deposits of finer-grained materials at various levels and of limited horf-zontal extent which may cause localized indications of artesian water pressures.
These localized artesian pressures could be misinterpreted as indications of an
. tensive confining layer. On this basis, the permittee and its consultants have concluded that no drawdown from construction dewatering of the Bailly site should occur at distances greater than about 1,500 feet from the excavation.
The NRC staff has not made any judgment relating to the specific lateral extent of either the aquifers or the confining layers in tne <f cinity of the Bailly site.
While we acknowledge the existence of confining layers at several locations, we conclude that tne lateral extent of confining layers and, therefore, separate and distinct aquifers is questionable in certain areas. Rather than pursuing tnis question with respect to its effect on our evaluation of tne Bailly construction dewatering, we have chosen instead to rely on the permittee's monitoring and mitigation program as a means of minimizing the likelihood of any consequences occurring offsite due to Nnstruction cewatering at the Bailly site.
D.
Monitoring and Mitigation Program The NRC staff has required tnat an extensive monitoring and mitigation program related to dewatering be implemented as a condition to tne permittee's CP. This monitoring program includes collecting and analyzing surface and groundwater levels and water quality data at a numoer of locations on the permittee's property and in tne adjacent National Lakest. ore. This program has been supplementad oy groundwater data collected by the U.S.G.S. and by the Betnlenem Steel Company.
Evaluation of both the surf ace anc groundwater data provides a measure of the l
effects C -he ash ponds, construction dewatering and long-term precipitation /
i nfi l trat i v.. 'nfluences on groundwater levels. ' e find that most storms do not produce corresponding short-term increases in groundwater levels. The effects that are observed are primarily seasonal changes in the groundwater levels in I
the range of about three to four feet as recorded in the well water levels.
l The mitigation portion of tne permittee's program requires tnat it increase water levels in the surficial aquifer (unit 1) near the permittee's eastern property line adjacent to the National Lakesnore, by adding water via a trickling drain so as to maintain groundwater levels close to that which would exist in the absence of
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any construction dewatering at the Sailly site. This mitigation concept is a relative 1/ l l
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simple and effective approach. Namely, by artifically preventing the offsite groundwater levels from receding below the levels whicn would exist in the absence of construction dewatering, NIPSCO can ensure that no offsite effects due to Bailly construction dewatering will occur. Comparisons of water levels during active periods of dewatering at the Bailly site with historical records will provide an indication to initiate the mitigation program.
E.
Modeling of the Groundwater During tne course of our CP review and the subsequent hearings, the NRC staff considered the regulatory need and technical feasibility of constructing a model of the groundwater environment. These considerations were made botn before and af ter knowledge of the U.S.G.S. modeling effort. At that time, we concluded that such modeling was not necessary to accomplish our regulatory purposes at the Sailly si te. Furthermore, we concluded from a technical standpoint that the state-of-the-art ano the site-specific conditions would most likely not produce a conclusive evaluation from this modeling. The site-specific conditions to which we refer are the discontinuities i the aquifers in the vicinity of tne Bailly site as dd scussed in Section C.
F. Basis for tne NRC Staff's Prior Evaluations We have reviewed the testimony by all parties in the CP hearing and in the hearing on the slurry wall, the data *nat existed when the staff testimony was prepared, and the subsequent data and studies that have been generated. We summarize the con-clusions wnich provided tne bas's for the NRC staff's previous testimony as follows:
1.
The materials underlying tne Bailly site and the surrounding area, including National Lakeshore, consist of lenticular deposits (lenses), principally the sands, clays, small gravels and combinations thereof.
ii.
The lateral and vertical extent of lenses of different material types vary considerably.
The nydrologic characteristics of the materials in the individual lenses iii.
have some variation but the mean characteristics of different lenses differ Further, the characteristics of the more clayey lenses are dramatically.
such that groundwater flow through them, either horizontally or vertically, is greatly restricted comoared to the surrounding materials.
Specifically, the more clayey lenses restrict water movement and tend to confine water movement in the materials aoove and below them, iv.
Prior to excavation, the general direction of the groundwater flow in the vicinity of tne excavation was to the north and west, toward Lake Sticnija1.
After ccmpletion of backfill operations, the groundwater flow direction will return to its general nortnwesterly flow, Without mitigation, operation of the ash ponds with or witncut sealing and v.
construction dewatering would signift:nntly alter natural grounawater levels and flow rates both on the Sailly site and offsite.
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vi.
' Groundwater levels at deptns on the Bailly site and offsite could vary, reflecting the presence of a confining or semi-confining layer or layers, but the degree of confinement is not complete either vertically or hori-zontally. This is evidenced by the fact th:t the water levels in both the surface _(unit 1) and confined aquifers (unit 3) vary considerably in time and space.
Furthermore, we concluded that estimates of the groundwater levels at the Bailly site boundaries in the absence of construction dewatering were: (1) subject to both short-term and long-term fluctuations induced by precipitation; (2) greatly influenced by the unlined ash ponds; and (3) subject to error due to a number of factors, including the variabilty in the hydrologic characteristics of the under-lying materials in this region.
G.
NRC Staff Conclusions Regarding the Impact of Construction Dewatering at the Bailly Site Due to the CP Extension We have once more considered the question of modeling in view of the issues involved, particularly with respect to the large amount of data presently available but which was not available at the time of the CP and cost-CP hearings. We again conclude tnat such modeling could be useful but that..,e results of such medeling in the Bailly/ National Lakeshore region still cannot be expected to produce accurate estimates. In particular, our position is tnat the interpretations of such model results can be misleading.
In our opinion, the U.S.G.S. has properly characterized its model studies by placing appropriate limitations on the interpretations of the results.
Based en our conclusion tnat accurate estimates of the effects of construction dewatering at the Bajily site cannot be made at the distances of interest in this case, we reaffirm our prior position that groundwater levels near the eastern boundary of the Bailly site with the National Lakeshore can be controlled so that the effects of construction dewatering are not expected to extend offsite, thereby minimizing impacts on the National Lakeshore. Specifically, we have reassessed the basis for our past conclusions cited in Section F acove considering:
(1) the large amount of groundwater data presently available; (2) the present construction dewatering plans; (3) tne sealing of the ash ponas; and (4) the MIPSCO monitoring /mitig ttion With one modification wnich is discussed below, we conclude that the program.
NIPSCO monitoring / mitigation program whicn minimizes offsite impacts from con-struction dewatering and wnich we nave previously found acceptable, can still be used with a high probability of success a,d is, therefore, acceptable.
Fhe data that nave been collected since tne CP and slurry wall hearings and the permittee's plans for well point dewatering of the confined aquifer (unit 3),
confirm that water pressures at depths below the surficial aquifer (unit 1) will be recuced near the Sailly excavation. The extent to whicn these reduced pressures will result in declines of the water level in the surficial aquifer (unit 1) at the site boundary, or in any aquifer offsite, is uncertain. On :nis basis, ne conclude that there is a need for a modification to the monitoring and mitigation program specifically oriented towards the piezometric levels in the unit 3 aquifer. __
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!o While the permittee has vercally agreed to submit tne acpropriate program codifications to tne RC staff for review, it has not yet d'ne so. Je will require tne mooifications to the permittee's monitoring and mitigation program to ce suanittec for our review and approval prior to canpleting tne CP extension hearing.
We will issue a supplement to tnis environmental impact assessment wnen we com-plete our review of NIPSCO's proposed codifications to its dewatering progra:a.
Cn the casis tnat a monitoring and mitigation program in both the units 1 and 3 aquifers can be readily implemented by NIPSCO and that tne present NIPSCO program for conitoring tne water levels in the surficial aquifer is still acceptable, we find tnat there vill be no adverse impact on tne water levels in tne adjacent I. diana Dunes Mtional Iakeshore, including the water levals in the vicinity of tne Cowles Sog National Landmark. Accordingly, there wi'l also ce no adverse impact on the environment of the ational Iakesnore.
Conclusion and 3 asis for Necative Declaration Ihe EC staff has reviewed and evaluated environmental affects whien may result from tne requested extension by NIPSCO of tne latest completion date of the existing construction permit for the Sailly Generating Station, Nuclear-1. The h7.C staff has concentrated its assessm:nt principally on possicle impacts due to tne larger lacor force at the Sailly site tnan was previously estimated and due to the need to continue construction dewatering for a few.nre years from the present. 'These are judged to ce the only potentially significant factors.in assessing any environ-tental effects resulting from tne celay in canpleting the 3ailly facility.
Cn :ne casis of the foregoing discussion and our evaluation and pending sucmittal of acceptacle modifications to NIPSCO's conitoring and mitigation program for construction dewatering, we conclude that tnere will be no significant environmental impact attricutacle to ene proposed action other than :nat already predicted anc cescribed in the Commission's FES issued in Featuary 1973 a.d :n our testi;aony sucmitted to ne Atanic Safety and Licensing 30ard in early 1975 for tne nearing on the slurry wall. Raving made this conclusion, the Cor:nission further concludes tnat no environmental i tpact statement for tne proposed action need ce prepared and tnat a negative declaration stating nis is appropriate. Tte cuoject enange to tne const :ction permit is judged not to ce a major federal action significantly affectiag tne quality of the numan environment.
Cated: July 17,1931
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