[Federal Register Volume 63, Number 169 (Tuesday, September 1, 1998)]
[Notices]
[Pages 46489-46491]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 98-23460]


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NUCLEAR REGULATORY COMMISSION

[Docket No. 50-263]


Northern States Power Company; Monticello Nuclear Generating 
Plant; Environmental Assessment and Final Finding of No Significant 
Impact

    The U.S. Nuclear Regulatory Commission (the Commission) is 
considering issuance of an amendment to Facility Operating License No. 
DPR-22, issued to Northern States Power Company (NSP), for operation of 
the Monticello Nuclear Generating Plant (MNGP) located in Wright 
County, Minnesota.

Environmental Assessment

Identification of the Proposed Action

    By letter dated July 26, 1996, as revised December 4, 1997, NSP 
requested an amendment to License No. DPR-22 for MNGP that would 
increase the maximum power level from 1670 megawatts-thermal (MWt) to 
1775 MWt. This change is approximately 6.3 percent above the current 
maximum license power level and is considered an extended power rerate.

The Need for the Proposed Action

    NSP has projected the need for additional generation resources 
through a comparison of needs to available resources. NSP has projected 
a shortfall of generating capacity in the future. The proposed action 
would provide increased reactor power, thus adding an additional 26 MW 
of reliable electrical energy generating capacity without major 
hardware modifications to the plant. Hardware changes are not needed 
because of improvements in technology, performance, and design. These 
improvements have resulted in a significant increase in the difference 
between the calculated safety analysis results and licensing limits 
established by the original license.

Environmental Impacts of the Proposed Action

    The issuance of the operating license for MNGP stated that any 
activity authorized by the license is encompassed by the overall action 
evaluated in the Final Environmental Statement (FES), which was issued 
in November 1972. The license for MNGP allowed a maximum reactor power 
level of 1670 MWt. NSP submitted an environmental evaluation supporting 
the proposed power rerate action and provided a summary of its 
conclusions concerning both the radiological and nonradiological 
environmental impacts of the proposed action. The evaluations performed 
by the licensee concluded that the environmental impacts of power 
rerate are well bounded or encompassed by previously evaluated 
environmental impacts and criteria established by the staff in the FES. 
A summary of the nonradiological and radiological effects on the 
environment that may result from the proposed amendment is provided 
below.
Nonradiological Impacts
    Land Use. Power rerate does not modify land use at the site. No new 
facilities, access roads, parking facilities, laydown areas, or onsite 
transmission and distribution equipment, including power line right of 
way, are needed to support the rerate or operation after rerate. No 
change to above or below ground storage tanks would occur as a result 
of power rerate and the rerate does not affect land with historical or 
archeological sites.
    Based on the operating history at the MNGP, the effects of drift, 
icing, and fog have been negligible. The frequency of fog and drift 
were provided by the licensee at the time of original licensing and the 
impacts of that frequency of drift and fog are bounded by the 
evaluation contained in the FES. The FES assumed cooling tower 
operation of 7 months, with the total fogging time estimated at 45 
hours per year. If the cooling tower fogging rate is assumed to 
increase proportional to the proposed power increase, the amount of 
fogging due to power rerate could increase by approximately 6.3 percent 
above the normal summer operating period of 4 months. Additionally, the 
licensee determined that power rerate may involve an extra week of 
cooling tower operation. Taking into account the additional fogging 
rate and the additional cooling tower operation, the conditions at 
power rerate are still bounded by the FES.
    The increase in power level would cause a current and magnetic 
field increase on the onsite transmission line between the main 
generator and the plant substation. The line is located entirely within 
the fenced, licensee-controlled boundary of the plant, and it is not 
expected that members of the public or wildlife would be affected. 
Exposure from magnetic fields from the offsite transmission system is 
not expected to increase significantly.
    Water Use. Power rerate does not involve a significant increase in 
water use at MNGP. Both ground and surface water appropriation limits 
are established by the Minnesota Department of Natural Resources. 
Operating history shows that over the last 5 years MNGP has used less 
than 13 million gallons of ground water per year. The annual limit 
established in the permit for groundwater use is 15 million gallons. 
Power rerate is not expected to change the groundwater usage and, 
therefore, operation within the allowable limit would continue. Under 
the surface water appropriation limit, MNGP may withdraw a maximum of 
645 cubic feet per second (cfs) from the Mississippi River. There are 
special restrictions when the river flow is particularly high or low; 
however, power rerate is not expected to change the surface water 
requirements of the plant and, therefore, current appropriation limits 
would be maintained. Power rerate would result in an increase in the 
evaporation rate of the cooling towers resulting in an increase in 
evaporative losses from the river. Assuming the evaporation rate of the 
cooling towers increases linearly in proportion to the power increase, 
the evaporation rate would increase to 4400 acre-ft/yr [acre-foot per 
year]. The value assumed in the FES was 5000 acre-ft/yr evaporative 
losses; therefore, the FES is still bounding.
    Discharges to the water are governed by the National Pollutant 
Discharge Elimination System (NPDES) permit, issued by the State of 
Minnesota. Temperature and effluent limits at certain points are 
established in the permits. As a result of power rerate, a slight 
increase in circulating water discharge temperature is projected to 
occur. This is due to an increase in heat rejected by the condenser due 
to the increased power levels and increased steam flow. A conservative 
estimate by the licensee predicts a maximum 1.7  deg.F [degrees 
Fahrenheit] increase in the temperature of the water entering the 
discharge canal. This increase would

[[Page 46490]]

not result in exceeding the limits delineated in the FES or the limits 
established by the State in the permit. Additionally, temperature 
monitoring is continuous and this maximum temperature increase would 
occur only at certain times of the year with certain river flows. In 
the past, when MNGP has approached the limit designated in the NPDES 
permit, NSP has reduced power at the plant to maintain compliance; this 
will continue in the future. The slight increase in temperature does 
not require any changes to permit requirements and would not result in 
any significant impacts to the environment that are different from 
those previously identified or change the previous Clean Water Act 
Section 316(a) demonstration concerning thermal plume in the 
Mississippi River.
    Power rerate would not introduce any new contaminants or pollutants 
and would not significantly increase the amount of potential 
contaminants previously allowed by the State. NSP will continue to 
adhere to effluent limitation and monitoring requirements as part of 
compliance with the NPDES permit. As a result of the additional week of 
cooling tower operation, a slight increase in normal bromine and sodium 
hypochlorite injection may be required; however, the effluent 
concentrations would continue to be well below the NPDES permit limits. 
Continuous flowrate monitoring at designated points will continue.
    Over the years of operation, a number of modifications to the 
intake structure have been implemented to reduce cold shock, 
impingement, and entrainment of organisms and fish. Because the 
discharge canal inlet temperature is expected to increase 1.7  deg.F at 
power rerate, the overall discharge canal temperature is not 
significantly increased; therefore, the temperature decrease during 
cold shock is not significantly changed.
    Additionally, impingement and entrainment mortality of drift 
organisms is not increased above what was previously evaluated by the 
staff.
Other Impacts
    No significant increases or changes to the noise generated by MNGP 
are expected as a result of power rerate; therefore, the FES remains 
bounding. A small number of endangered and threatened species exist 
within the licensee-controlled area at MNGP. Using information from the 
Minnesota Department of Natural Resources, the licensee performed a 
biological assessment of the impact of power rerate on these species. 
The assessment did not identify any impacts. Power rerate would not 
result in any significant changes to land use or water use, or result 
in any significant changes to the quantity or quality of effluents; 
therefore, no effects on the endangered or threatened species or on 
their habitat are expected as a result of power rerate.
    The proposed power rerate would not change the method of generating 
electricity nor the method of handling any influent from the 
environment or nonradiological effluents to the environment. Therefore, 
no changes or different types of nonradiological environmental impacts 
are expected.
Radiological Impacts
    MNGP has a number of radioactive waste systems designed to collect, 
process, and dispose of solid, liquid, and gaseous radioactive waste. 
No changes to these systems are required for power rerate conditions. 
The licensee considered the effect of the higher power level on solid 
radioactive wastes, liquid radioactive wastes, gaseous radioactive 
wastes, and radiation levels.
    As a result of power rerate, a slight increase in solid waste from 
the reactor water cleanup (RWCU) system demineralizers and condensate 
demineralizers would occur. This is due to more frequent filter 
backwashes. Additional RWCU filter backwashes would result in less than 
1 cubic meter of additional resin waste per year; condensate 
demineralizer filter backwashes are estimated to result in an 
additional 4 cubic meters of resin waste per year. Therefore, the 
projected increase in spent resin volume is less than 6 cubic meters 
per year, which would bring the total generation rate to approximately 
55 cubic meters per year.
    In addition to the solid process waste, there are solid reactor 
system wastes generated from the plant. These include irradiated fuel 
assemblies and control blades. Due to extended burnup and the higher 
enrichments, the number of irradiated fuel assemblies is not expected 
to significantly increase the volume of waste; however, the activity of 
the waste generated from spent control blades and incore ion changers 
may increase slightly. This is due to the higher flux conditions 
expected under power rerate. Improvements in technology and longer fuel 
cycles are expected to offset this slight increase. The increase in 
waste would be insufficient to impact the amount of waste generated at 
the site. Further, the licensee believes ongoing efforts at MNGP to 
reduce radioactive wastes will balance the slight increase in waste 
that would be generated as a result of power rerate.
    The FES and Technical Specifications allow MNGP to discharge a 
limited amount of liquid radioactive waste. The FES concluded that, 
based on the allowed amounts, no adverse environmental impact would 
result from release of the allowable radioactive waste. However, since 
1972, an administrative limit of zero radioactive liquid release has 
been imposed by NSP. MNGP expects to keep the zero release 
administrative limit and remain well within the bounds of the FES.
    A slight increase in input to the liquid radioactive waste system 
is expected due to the increase in backwash frequency of the RWCU and 
condensate demineralizer system. However, the liquid radioactive waste 
input will be recycled instead of discharged and will not result in a 
significant increase in volume of liquid radioactive waste. Other 
sources of liquid radioactive waste such as valve packings, pump seal 
flows, drain waste, etc., are not expected to change or increase as a 
result of power rerate. Based on the above, it does not appear that 
power rerate will cause an increase in liquid radioactive waste above 
the presently allowed limits and will not affect compliance with the 
limits of 10 CFR Part 20 or Appendix I of 10 CFR Part 50.
    Gaseous radioactive waste effluents consist of two pathways: 
reactor building ventilation system and offgas system pathway. 
Operational experience at MNGP shows a 4-year average release of 688 
Ci/yr [curies per year] noble gas and 0.22 Ci/yr iodine and particulate 
release. The FES assumed release rates of 110,376 Ci/yr for noble gases 
and 0.75 Ci/yr for iodine and particulate releases. Assuming power 
rerate increases the offgas release rate linearly in proportion to the 
core thermal power increase, the increase in offgas stack release would 
be well below that assumed in the FES. Assuming the radioactivity of 
the reactor coolant system increases in a linear fashion proportional 
to the power increase, the reactor building release rate is well below 
that assumed in the FES. Based on the above, power rerate has an 
insignificant effect on the present production and activity of gaseous 
effluents released through the reactor building ventilation system and 
the offgas system pathways and the dose from effluent releases is well 
within the bounds of Appendix I to 10 CFR Part 50 and 10 CFR Part 20. 
The changes in core flux profile would result in increased consequences 
of a fuel defect for a bundle in a non-leak location; however, this 
continues to be bounded by the consequences for the peak bundle and 
those limits are not changed.

[[Page 46491]]

    Power rerate does not introduce any new or different radiological 
release pathways and does not increase the probability of an operator 
error or equipment malfunction that would result in a radiological 
release. Thus, there will be no significant increase in the types or 
amounts of radiological effluents.
    Tables S-3 and S-4 of 10 CFR 51.51 and 10 CFR 51.52, respectively, 
outline the environmental effects of uranium fuel cycle activities and 
fuel and radioactive waste transportation. The environmental evaluation 
supporting Table S-3 assumed a reference reactor with a specific 
capacity factor that results in an adjusted daily electricity 
production during a reference year. An average burnup and enrichment 
are also assumed. MNGP will not exceed the assumption of the reference 
reactor year, but will exceed the average burnup and fuel enrichment 
criteria as a result of power rerate. The environmental impacts of the 
higher burnup and enrichment values were documented in NUREG/CR-5009, 
``Assessment of the Use of Extended Burnup Fuels in Light Water Power 
Reactors,'' and discussed in the Environmental Assessment and Finding 
of No Significant Impact, which was published in the Federal Register 
on February 29, 1988 (53 FR 6040). The staff concluded that no 
significant adverse effects will be generated by increasing the burnup 
levels as long as the maximum rod average burnup level of any fuel rod 
is no greater than 60 Gwd/MtU [gigawatt-days per metric ton of 
uranium]. The staff also stated that the environmental impacts 
summarized in Tables S-3 and S-4 for a burnup level of 33 Gwd/MtU are 
conservative and bound the corresponding impacts for burnup levels up 
to 60 Gwd/MtU and uranium-235 enrichments up to 5 weight percent. These 
conclusions are applicable to MNGP since the burnup levels and 
enrichment amounts bound the values that will occur during Monticello 
rerate. Based on the above, there are no adverse radiological or 
nonradiological impacts associated with the use of extended fuel burnup 
and/or increased enrichment and, therefore, power rerate will not 
significantly affect the quality of the human environment.

Alternatives to the Proposed Action

    As an alternative to the proposed action, the staff considered 
denial of the proposed action (no-action alternative). Denial of the 
proposed action would result in no change in current environmental 
impacts of plant operation but would restrict operation to the 
currently licensed power level. The environmental impact of the 
proposed action and the alternative action are similar.

Alternative Use of Resources

    This action does not involve the use of any resources not 
previously considered in the Final Environmental Statement for the 
MNGP.

Agencies and Persons Consulted

    In accordance with its stated policy, on August 10, 1998, the NRC 
staff consulted with the Minnesota State official, Mr. Timothy 
Donakowski, of the Minnesota Department of Public Health, regarding the 
environmental impact of the proposed action. The State official had no 
comments.

Final Finding of No Significant Impact

    The staff has reviewed the proposed power rerate for the MNGP 
relative to the requirements set forth in 10 CFR Part 51. On January 
27, 1998, the staff published a draft Environmental Assessment in the 
Federal Register (63 FR 3929), for public comment. No comments were 
received.
    Based upon the environmental assessment, the Commission concludes 
that the proposed action will not have a significant effect on the 
quality of the human environment. Accordingly, the Commission has 
determined not to prepare an environmental impact statement for the 
proposed action.
    For further details with respect to the proposed action, see the 
licensee's submittals dated July 26, 1996, and December 4, 1997, which 
are available for public inspection at the Commission's Public Document 
Room, The Gelman Building, 2120 L Street, NW., Washington, DC, and at 
the local public document room located at the Minneapolis Public 
Library, Technology and Science Department, 300 Nicollet Mall, 
Minneapolis, Minnesota 55401.

    Dated at Rockville, Maryland, this 27th day of August 1998.

    For the Nuclear Regulatory Commission.
Cynthia A. Carpenter,
Director, Project Directorate III-1, Division of Reactor Projects--III/
IV, Office of Nuclear Reactor Regulation.
[FR Doc. 98-23460 Filed 8-31-98; 8:45 am]
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