Niagara Mohawk Power Corporation; Environmental Assessment and Finding of No Significant Impact

NUCLEAR REGULATORY COMMISSION

[Docket No. 50-410]

Niagara Mohawk Power Corporation; Environmental Assessment and

Finding of No Significant Impact

The U.S. Nuclear Regulatory Commission (the Commission) is

considering issuance of an amendment to Facility Operating License No.

NPF-69, issued to Niagara Mohawk Power Corporation (the licensee), for

operation of the Nine Mile Point Nuclear Station, Unit 2 (NMP-2),

located in Oswego County, New York.

Environmental Assessment

Identification of the Proposed Action

This Environmental Assessment has been prepared to address

potential environmental issues related to the licensee's application to

amend the NMP-2 operating license dated July 22, 1993, as supplemented

January 9, 1995. The proposed amendment would increase the licensed

core thermal power from 3323 MWt to 3467 MWt, which represents an

approximate increase of 4.3% over the current licensed power level.

This request is in accordance with the generic boiling water reactor

(BWR) power uprate program established by the General Electric Company

(GE) and approved by the U.S. Nuclear Regulatory Commission (NRC) staff

in a letter from W. Russell, NRC, to P. Marriotte, GE, dated September

30, 1991. Implementation of the proposed power uprate at NMP-2 will

result in an increase of steam flow to approximately 105% of the

current operating limit, but will require no changes to the basic fuel

design. Core reload design and fuel parameters will be modified as

power uprate is implemented to support the current 18-month reload

cycle. The higher power level will be achieved by expanding the power/

flow map and by increasing, slightly, reactor vessel dome pressure. The

maximum recirculation flow limit will not be increased over the

preuprate value. Implementation of this proposed power uprate will

require minor modifications, such as, resetting of the low set safety

relief setpoints, as well as the calibration of plant instrumentation

to reflect the uprated power. Plant operating, emergency, and other

procedure changes will be made where necessary to support uprated

operation.

The proposed action involves NRC issuance of a license amendment to

uprate the authorized power level by changing the operating license,

including Appendix A of the license (Technical Specifications). No

change is needed to Appendix B of the license (Environmental Protection

Plan--Nonradiological).

The Need for the Proposed Action

The proposed action would authorize the licensee to increase the

potential electrical output of NMP2 by approximately 45 megawatts and

thus would provide additional electrical power to service domestic and

commercial areas of the licensee's grid.

Environmental Impacts of the Proposed Action

The ``Final Environmental Statement (FES) related to operation of

Nine Mile Point Nuclear Station, Unit No. 2'' was issued May 1985

(NUREG-1085). By letter of July 22, 1993, the licensee submitted the

proposed amendment to implement power uprate for NMP2, which is the

subject of this environmental assessment. Section 11.3 of the NMP2

power uprate licensing topical report (GE report NEDC-31994P, Revision

1) which was submitted as Enclosure 3 to NMPC's July 22, 1993,

submittal, provided an environmental assessment of the proposed power

uprate. Some environmental effects will remain the same, while power

uprate may nominally increase others. Actual effects are at worst

proportional to the approximately 5% increase in turbine steam flow.

Increased core flow has no discernable effect on the environmental

assessment.

The licensee provided information regarding the nonradiological and

radiological environmental effects of the proposed action in the July

22, 1993, application and in its supplemental information dated January

9, 1995. The NRC staff has reviewed the potential nonradiological and

radiological effects of the proposed action on the environment as

described below. [[Page 11690]]

Nonradiological Environmental Assessment

Power uprate will not change the method of generating electricity

nor the method of handling any influents from minor effluents to the

environment. Therefore, no new or different types of environmental

impacts are expected.

The NRC staff reviewed the nonradiological impact of operation at

uprated power levels on influents from and effluents to Lake Ontario.

NMP-2 utilizes a closed-loop circulating water system and a natural

draft cooling tower for dissipating heat from the main turbine

condenser. Other equipment is cooled by the service water system. The

cooling tower and service water system are operated in accordance with

the requirements of the State Pollutant Discharge Elimination System

(SPDES) Permit No. NY-000-1015, which was issued by the New York State

Department of Environmental Conservation (NYSDEC) on October 26, 1994,

and became effective on December 1, 1994. It expires on December 1,

1999. This new discharge permit was issued by New York State since the

previous permit had expired.

The withdrawal of cooling water from Lake Ontario is expected to

increase slightly due to the increased heat loads. Emergency system

flows are expected to remain generally unchanged. Increased heat loads

are expected for nonsafety related loads such as the main generator

stator coolers, hydrogen coolers, and exciter coolers. These systems,

as well as other systems (e.g., RHR heat exchangers, emergency diesel

generator coolers, and spent fuel pool heat exchangers) noted in

Section 6 of the July 22, 1993, submittal are expected to require

additional cooling and an increase in flowrate. The increase in water

intake to the cooling tower is due to increased evaporation in the

cooling tower. The increase in flowrate is expected to be small and

within a nominal 5 percent increase. Conservatively assuming a 5

percent increase in the withdrawal rate, the intake approach flowrate

velocity is expected to increase from 0.5 fps to 0.53 fps. Observations

by the licensee have shown fish impingement to be very low and in most

cases nonexistent. The NYSDEC has evaluated the potential effects of

the current intake flowrate and has concluded that no special aquatic

studies are required to assess the biological impact. No aquatic

studies were included in the licensee's new SPDES discharge permit

which was effective December 1, 1994. The licensee has stated that

because the current intake flowrates are low and the aquatic impacts of

withdrawal are minimal, an increase of 5 percent is not expected to

result in a significant impact, if any impact at all. The NRC staff

agrees with the licensee's assessment and does not expect any

significant impact due to the 5 percent increase in withdrawal

flowrate.

The licensee does not expect an increase in the cooling tower

blowdown. The cooling tower blowdown rate is controlled by total copper

concentration in the circulating water system and the economic use of

water treatment chemicals. The current blowdown rate is approximately

40 percent of the designed rate and is restricted to ensure compliance

with the total copper concentration limitation imposed by the SPDES

permit and by economic use of water treatment chemicals. The licensee

has stated that if the blowdown rate was increased by 5-10 percent in

order to evaluate cooling tower efficiency and to reduce the cycles of

concentration of natural salts in the circulating water system, the

copper limitation could still be met and the flowrate impact would be

less than design. In addition, the NYSDEC has evaluated the service

water and cooling tower blowdown based on the original design

flowrates, as well as the state of the art technology of the discharge

diffuser. The NYSDEC has concluded that no thermal measurements or

thermal plume studies are necessary because of the low flowrates and

the design of the discharge structure. Therefore, the licensee

concluded that because the withdrawal rate is currently low and the

cooling tower blowdown rate is currently below original design, the 5

percent increase in water withdrawal or an increase in blowdown is not

expected to result in any additional environmental impact since any

increase in flowrate is expected to be no more than the original system

design. The NRC staff has reviewed the licensee's assessment and

concludes the increased flowrates will not result in a significant

increase in environmental impact.

The licensee has conservatively estimated that the power uprate

will result in an annual increase in dissolved solids from water

passing through the soil in the area of the Energy Center of

approximately 0.012 ppm. Since even the most sensitive species are not

affected by soil salinization of less than 1,280 ppm, it is highly

unlikely that even salt-sensitive species would be measurably affected

by this additional deposition rate during operation of the NMP-2

cooling tower at power uprate conditions. Therefore, the NRC staff has

concluded that the increase in cooling tower drift due to the proposed

power uprate will have no significant increase in environment impact

and would still be well below the levels of concern to local soil and

vegetation.

Nonradiological effluent discharges from other systems were also

considered. Nonradiological effluent limits for such systems as floor

and equipment drains are established in the SPDES permit. Discharges

from these systems are not expected to change significantly, if at all,

because operation at uprated power levels are governed by the limits in

the SPDES permit. Thus, the impact on the environment from these

systems as a result of operation at uprated power levels is not

significant.

With the exception of the cooling tower, all other significant

noise producing equipment associated with the service water and

circulating water systems are located inside buildings and/or well

below grade where the noise level would have little, if any,

environmental impact. There is no expected increase in cooling tower

noise levels associated with the proposed power uprate since there are

no plans to increase its flow rate as part of the proposed power

uprate. The main turbine and generator will operate at the same speed

and thus will not contribute to increased offsite noise. Although the

main station transformers will operate at a slightly (approximately 4.3

percent) increased kilovolt-ampere level, the slight increase will

cause an insignificant increase in the overall noise level. Therefore,

the NRC staff has concluded that the outside noise level increase will

be insignificant.

The licensee has stated that the proposed power uprate will not

require any changes to the SPDES discharge permit nor to the NMP-2

Environmental Protection Plan. The NRC staff agrees with this

assessment and, therefore, we have concluded that the proposed power

uprate will have an insignificant impact on the nonradiological

elements of concern.

Radiological Environmental Assessment

The licensee evaluated the impact of the proposed power uprate

amendment to show that the applicable regulatory acceptance criteria

relative to radiological environmental impacts will continue to be

satisfied for the uprated power conditions. In conducting this

evaluation, the licensee considered the effect of the higher power

level on liquid radioactive wastes, gaseous radioactive wastes, and

radiation levels both in the plant and offsite during both normal

operation and post-accident.

The floor drain collector subsystem waste collector subsystem both

receive [[Page 11691]] inputs from a variety of sources (e.g., leakage

from component cooling water system, reactor coolant system, condensate

and feedwater system, turbine plant cooling water system, and auxiliary

steam system). However, leakages from these systems are not expected to

increase significantly since the operating pressures of these systems

are either being maintained constant or are being increased only

slightly due to the proposed power uprate.

The largest single source of liquid radioactive waste is from the

ultrasonic cleaning of the condensate demineralizers. These

demineralizers remove activated corrosion products which are expected

to increase proportionally to the proposed power uprate. However, the

total volume of processed waste is not expected to increase

significantly, since the only appreciable increase in processed waste

will be due to the slightly more frequent cleaning of these

demineralizers. Based on a review of plant effluent reports and the

slight increase expected due to the proposed power uprate, the NRC

staff has concluded that the slight increase in the processing of

liquid radioactive wastes will not have a significant increase in

environment impact and that requirements of 10 CFR part 20 and 10 CFR

part 50, appendix I, will continue to be met.

Gaseous radioactive effluents are produced during both normal

operation and abnormal operation occurrences. These effluents are

collected, controlled, processed, stored, and disposed of by the

gaseous radioactive waste management systems which include the various

building ventilation systems, the offgas system, and the standby gas

treatment system (SGTS). The concentration of radioactive gaseous

effluents released through the building ventilation systems during

normal operation is not expected to increase significantly due to the

proposed power uprate since the amount of fission products released

into the reactor coolant (and subsequently into the building

atmosphere) depends on the number and nature of fuel rod defects and is

not dependent on reactor power level. The concentration of activation

products contained in the reactor coolant is expected to remain

unchanged, since the linear increase in the production of these

activation products will be offset by the linear increase in steaming

rate. Therefore, based on its review of the various building

ventilation systems, the NRC staff has concluded that there will not be

a significant adverse effect on airborne radioactive effluents as a

result of the proposed power uprate.

Radiolysis of the reactor coolant causes the formation of hydrogen

and oxygen, the quantities of which increase linearly with core power.

These additional quantities of hydrogen and oxygen would increase the

flow to the recombiners by 4.3 percent during uprated power conditions.

The offgas system was originally designed for 105 percent of warranted

steam flow which would not be exceeded during operation at the proposed

uprated power level. Therefore, no changes will be required in the

offgas system and since the offgas system will be operated within the

originally evaluated design conditions, there will be no environmental

impact that was not previously evaluated.

The SGTS is designed to minimize offsite radiation dose rates

during venting and purging of both the primary and secondary

containment atmosphere under accident or abnormal conditions. This is

accomplished by maintaining the secondary containment at a slightly

negative pressure (more negative than or equal to -0.25 inch water

gauge) with respect to the outside atmosphere and discharging the

secondary containment atmosphere through high-efficiency particulate

air (HEPA) filters and charcoal absorbers. As noted in the Updated

Safety Analysis Report (USAR), the SGTS charcoal absorbers are designed

for a charcoal loading capacity of 10 mgI/gC and get the design

requirements for 30-day and 100-day loss-of-coolant accident (LOCA)

scenarios. The proposed power uprate would increase the post-LOCA

iodine loading by 4.3 percent but the charcoal loading would still

remain within the 10 mgI/gC loading and therefore, there would be no

significant increase in environmental impact.

The licensee has evaluated the effects of the power uprate on in-

plant radiation levels in the NMP-2 facility during both normal

operation and post-accident. The licensee has concluded that radiation

levels during both normal operation and post-accident may increase

slightly (at most, proportional to the increase in power level). The

slight increases in in-plant radiation levels expected due to the

proposed power uprate are not expected to affect radiation zoning or

shielding requirements. Individual worker occupational exposures will

be maintained with acceptable limits by the existing as low as is

reasonably achievable (ALARA) program which the licensee uses to

control access to radiation areas. Therefore, the NRC staff has

concluded that the slightly increased in-plant radiation levels will

not have a significant environmental impact.

The offsite doses associated with normal operation are not

significantly affected by operation at the proposed uprated power level

and are expected to remain well within the limits of 10 CFR part 20 and

10 CFR part 50, appendix I. These limits are imposed by Technical

Specifications 3/4.11.1, 3/4.11.2, 3/4.11.3, and 3/4.11.4, which will

not be changed by the proposed power uprate. Therefore, the NRC staff

has concluded that the offsite doses due to normal operation at the

proposed power uprate conditions will not result in a significant

environmental impact.

The dose evaluations for design basis accidents were performed for

issuance of the current operating license based on 105 percent of the

current rated power level. The proposed power uprate would be within

the assumptions used during original licensing of the plant and,

therefore, there will be no increase in environmental impacts over

those evaluated in the NRC staff's Final Environmental Statement

related to the operation of Nine Mile Point Nuclear Station, Unit No. 2

(NUREG-1085), May 1985.

The NRC staff has concluded that the NRC's FES (NUREG-1085) is

valid for operation at the proposed uprated power conditions. The NRC

staff also concluded that the plant operating parameters impacted by

the proposed uprate would remain within the bounding conditions on

which the conclusions of the FES are based.

The NRC staff has reviewed the licensee's reevaluation of the

potential radiological and nonradiological environmental impacts for

the proposed action. On the basis of this review, the NRC staff finds

that the radiological and nonradiological environmental impacts

associated with the proposed small increase in power are essentially

immeasurable and do not change the conclusion in the FES that the

operation of NMP-2 would cause no significant adverse impact upon the

quality of the human environment.

Accordingly, the Commission concludes that this proposed action

would result in no significant radiological or nonradiological

environmental impact.

Alternative to the Proposed Action

Since the Commission has concluded there is no measurable

environmental impact associated with the proposed action, any

alternative with equal or greater impact need not be evaluated. The

principal alternative would be to deny the requested amendment. Denial

would not significantly reduce the environmental impact of plant

operations, but would restrict operation [[Page 11692]] of NMP-2 to the

currently licensed power level. Denial of the amendment would prevent

the facility from generating the approximately additional 45 MWe that

is obtainable from the existing plant.

Alternative Use of Resources

This action does not involve the use of any resources not

previously considered in the ``Final Environmental Statement related to

the operation of Nine Mile Point Nuclear Station, Unit No. 2,'' dated

May 1985.

Agencies and Persons Consulted

The Commission's staff reviewed the licensee's request and

consulted with the New York State official regarding the environmental

impact of the proposed action. The State official had no comment

regarding the NRC's proposed action.

Finding of No Significant Impact

Based upon the foregoing 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 license amendment.

For further details with respect to this action, see the

application for amendment dated July 22, 1993, as supplemented January

9, 1995. These documents are available for public inspection at the

Commission's Public Document Room, The Gelman Building, 2120 L Street,

NW, Washington, DC 20555 and at the Reference and Documents Department,

Penfield Library, State University of New York, Oswego, New York 13126.

Dated at Rockville, Maryland, this 24th day of February 1995.

For the Nuclear Regulatory Commission.

Ledyard B. Marsh,

Director, Project Directorate I-1, Division of Reactor Projects--I/II,

Office of Nuclear Reactor Regulation.

[FR Doc. 95-5137 Filed 3-01-95; 8:45 am]

BILLING CODE 7590-01-M