Draft Environmental Assessment; Relating to a Proposed License Amendment To Increase the Maximum Rated Thermal Power Level at the Monticello Nuclear Generating Plant

NUCLEAR REGULATORY COMMISSION

[Docket No. 50-263]

Draft Environmental Assessment; Relating to a Proposed License

Amendment To Increase the Maximum Rated Thermal Power Level at the

Monticello Nuclear Generating Plant

AGENCY: Nuclear Regulatory Commission.

ACTION: Notice of opportunity for public comment.

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SUMMARY: The Nuclear Regulatory Commission has prepared a draft

environmental assessment related to the Northern States Power Company's

(NSP's) request for a license amendment to increase the maximum rated

thermal power level from 1670 megawatts-thermal (MWt) to 1775 MWt. As

stated in the NRC staff's position paper on the Boiling-Water Reactor

Extended Power Uprate Program dated February 8, 1996, the staff has the

option of preparing an environmental impact statement if it believes a

significant impact results from the power uprate. The staff did not

identify a significant impact related to the NSP's request and,

therefore, the NRC staff documented its

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environmental review in an environmental assessment (EA). In accordance

with the February 8, 1996, staff position paper, the draft EA and

finding of no significant impact is being published in the Federal

Register for a 30-day comment period.

DATES: Comment period expires February 26, 1998. Comments received

after this date will be considered if it is practical to do so, but the

Commission is able to assure consideration only for comments received

on or before this date.

ADDRESSES: Submit written comments to Chief, Rules Review and

Directives Branch, U.S. Nuclear Regulatory Commission, Mail Stop T-6D-

69, Washington, DC 20555-0001. Written comments may also be delivered

to 11545 Rockville Pike, Rockville, Maryland, from 7:30 am to 4:15 pm,

Federal Workdays. Copies of written comments received may be examined

at the NRC Public Document Room, 2120 L Street, N.W. (Lower Level),

Washington, DC.

FOR FURTHER INFORMATION CONTACT: Tae Kim, Office of Nuclear Reactor

Regulation, Mail Stop O-13D18, U.S. Nuclear Regulatory Commission,

Washington, DC 20555-0001, telephone (301) 415-1392.

SUPPLEMENTARY INFORMATION: 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,

for operation of the Monticello Nuclear Generating Plant located in

Wright County, Minnesota. The Commission's draft environmental

assessment and finding of no significant impact related to the subject

license amendment is provided below:

Environmental Assessment

1.0 Introduction

1.1 Description of Proposed Action

By letter dated July 26, 1996, as revised December 4, 1997,

Northern States Power Company (NSP) requested an amendment to License

No. DPR-22 for the Monticello Nuclear Generating Plant (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

uprate.

1.2 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.

2.0 Environmental Impacts

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 uprate 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

uprate 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.

2.1 Nonradiological Impacts

2.1.1 Land use. Power uprate 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 uprate or operation after

uprate. No change to above or below ground storage tanks would occur as

a result of power uprate and the uprate 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 uprate could increase by approximately 6.3 percent

above the normal summer operating period of 4 months. Additionally, the

licensee determined that power uprate 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 uprate 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.

2.1.2 Water Use. Power uprate 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 uprate 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 uprate is not expected to

change the surface water requirements of the plant and, therefore,

current appropriation limits would be maintained.

Power uprate 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 uprate, a slight

increase in circulating water

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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 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 uprate 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 uprate, 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.

2.1.3 Other impacts. No significant increases or changes to the

noise generated by MNGP are expected as a result of power uprate;

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

uprate on these species. The assessment did not identify any impacts.

Power uprate 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 uprate.

The proposed power uprate 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.

2.2 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 uprate 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 uprate, 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 uprate. 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 uprate.

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 uprate. Based on the above, it does not appear that

power uprate 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 [curie 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

uprate 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 uprate 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

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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.

Power uprate 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.

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 uprate. 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. Based

on the above, there are no adverse radiological or non-radiological

impacts associated with the use of extended fuel burnup and/or

increased enrichment and, therefore, power uprate will not

significantly affect the quality of the human environment.

3.0 Alternatives

As an alternative to the proposed action, the staff considered

denial of the proposed action. 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.

4.0 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.

5.0 Basis and Conclusions for Not Preparing an Environmental Impact

Statement

The staff has reviewed the proposed power uprate for the MNGP

relative to the requirements set forth in 10 CFR Part 51. Based upon

the environmental assessment, the staff has concluded that there are no

significant radiological or nonradiological impacts associated with the

proposed action and that the proposed license amendment will not have a

significant effect on the quality of the human environment. Therefore,

the Commission has determined pursuant to 10 CFR 51.31 not to prepare

an environmental impact statement for the proposed amendment but to

prepare this draft finding of no significant impact.

For further details with respect to the proposed action, see the

licensee's letter dated July 26, 1996, as revised by letter dated

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 21st day of January 1998.

Cynthia A. Carpenter,

Acting Director, Project Directorate III-1, Division of Reactor

Projects--III/IV, Office of Nuclear Reactor Regulation.

[FR Doc. 98-1903 Filed 1-26-98; 8:45 am]

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