ML18038B960

Environ Assessment BFN Power Uprate Project, Per TS Change TS-384

ML18038B960
Person / Time
Site:	Browns Ferry
Issue date:	08/31/1997
From:	TENNESSEE VALLEY AUTHORITY
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NUDOCS 9710070316
Download: ML18038B960 (22)

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ENVIRONMENTAL ASSE SSMENT BROWNS FERRY NUCLEAR PL2WT POWER UPRATE PROJECT PROPOSED TECHNICAL SPECIFICATION (TS)

CIRQUE (TS )

TS-384 TENNESSEE VALLEY AUTHORITY AUGUST 1997 97i00703ib 97iOOi 05000260 PDR ADQCK P PDR

ENVIRONMENTAL ASSESSMENT POWER UPRATE, BROWNS FERRY NUCLEAR PLANT Table of Contents 1.0 PURPOSE AND NEED FOR ACTION . ~ ~ 1 1 .1 Introduction ......................................... 1 1.2 Identification And Need For The Proposed Project .... 1 2.0 ALTERNATIVES ......................... ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ 2 3.0 ENVIRONMENTAL IMPACTS OF THE PROPOSED ACTION .......... 2 3.1 Non Radiological Environmental Impacts .............. 3 3.2 Radiological Environmental Impacts . . .......... 4 Table 1 Maximum Dose Due to Radioactive Effluent ....... 6 3.3 Accident Related Raiodological Environmental Impacts . 6 Table 2 LOCA Radiological Consequences ........ ~ ~ ~ ~ ~ ~ ~ ~ t 7 Table 3 MSLBA Radiological Consequences ....... ~ ~ ~ ~ ~ ~ ~ ~ 8 Table 4 FHA Radiological Consequences ......... ~ ~ ~ ~ ~ ~ ~ ~ ~ 8 Table 5 CRDA Radiological Consequences .. ~ ~ ~ 9 3.4 Other Environmental Impacts .......... ~ ~ ~ ~ ~ ~ 9 4.0 AGENCIES/PERSONS CONSULTED .. 9

5.0 REFERENCES

........ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ 0 ~ ~ ~ ~ 12 3.3.

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ENVIRONMENTAL ASSESSMENT POWER UPRATE, BROWNS FERRY NUCLEAR PLANT 0 'URPOSE AND NEED FOR ACTION 1.1 Introduction The Browns Ferry Nuclear Plant (BFN) is located on an 840-acre tract on the north shore of Wheeler Reservoir in Limestone County, Alabama, at Tennessee River mile 294. The site is approximately 10 miles northwest of Decatur, Alabama, and 10 miles southwest of Athens, Alabama. A Final Environmental Statement for Browns Ferry Nuclear Plant Units 1, 2, and 3 was made available to the public on July 14, 1971.

In November 1996, the Tennessee Valley Authority (TVA)

Executive Committee approved an Integrated Plant Improvement Project (IPIP) for Browns Ferry Units 2 and 3 contingent on completion of the agency' National Environmental Policy Act (NEPA) review. The project provides for implementation of Power Uprate, 24 Month Operating Cycles, Hydrogen Water Chemistry, and installation of Auxiliary Decay Heat Removal System. Implementation of these items will provide an increase in generation capacity and help ensure long term reliability of certain reactor components.

Three of the four activities identified in the IPIP, namely, 24 Month Operating Cycles, Hydrogen Water Chemistry, and installation of Auxiliary Decay Heat Removal System came under a categorical exclusion in TVA's NEPA regulations covering minor upgrades of TVA facilities. The fourth activity, Power Uprate, is the proposed action being evaluated in this Environmental Assessment (EA). This EA is being prepared in accordance with the National Environmental Policy Act (NEPA) and TVA's implementing procedures. It addresses specific issues and potential environmental impacts associated with the Power Uprate at BFN.

1.2 Identification And Need For The Proposed Project This Environmental Assessment addresses potential environmental issues related to a proposed uprate of the power output of BFN's Units 2 and 3. The proposed project would increase the licensed core thermal power from 3293 megawatts thermal (MWt) to 3458 MWt for each unit, which represents an increase of 5 percent over the current licensed power level. The thermal power uprate concept allows the safe utilization of plant system operating margin. The proposed project is in accordance with the generic boiling water reactor power uprate program

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ENVIRONMENTAL ASSESSMENT POWER UPRATE, BROWNS FERRY NUCLEAR PLANT established by the General Electric Company, and approved by the Nuclear Regulatory Commission in a letter dated September 30, 1991. (Reference 1)

The increase in steam flow is expected to produce an increase of approximately 5% in gross electrical generation for each unit. This will increase the potential electrical output of BFN by approximately 55 megawatts for units 2 and 3, thus providing additional electric power to service TVA's grid. Uprate has been widely recognized by the industry as the safest and most cost effective method to increase generating capacity. A cost benefit study was performed which demonstrated that based on the projected cost and demand for power, uprate provides a substantial economic benefit to TVA.

2.0 ALTERNATIVES Browns Ferry is currently licensed to produce electric power and is operating within the license limitations. In relation to the proposed action, TVA would request a license amendment from NRC to increase the operating power levels of BFN Units 2 and 3 by 5-:. The only alternative to the proposed action is no action. The no action alternative would continue operation of BFN Units 2 and 3 at their current licensed power levels. This would result in no change in current environmental impacts of plant operation, but would restrict TVA from obtaining the benefits of increased electrical output from the Browns Ferry units.

The preferred alternative is the proposed action to request a license amendment to operate BFN Units 2 and 3 at an increased 5% power level.

3.0 ENVIRONMENTAL IMPACTS OF THE PROPOSED ACTION The proposed action would not change the method of generating electricity at Browns Ferry nor the methods of handling influents from the environment or effluents to the environment. Therefore, no new or different types of nonradiological environmental impacts are expected. The major portion of the work involved in implementing uprate involves performing engineering analyses, revising procedures, and preparing the required licensing submittals.

No major hardware modifications should be required to implement the power uprate project. The environmental resources which could be impacted by the proposed action are the heat rejection to the Tennessee River, and the increases in radiological effluents to the environment. There would be no adverse environmental effects from the no action alternative.

k ENVIRONMENTAL ASSESSMENT POWER UPRATE, BROWNS FERRY NUCLEAR PLANT Non Radiological Environmental Impacts Under normal operation, BFN uses a once-through circulating water system to dissipate heat from the main turbine condensers. Water is withdrawn from the Tennessee River by the plant intake system and is discharged back to the river from submerged diffusers located on the river bottom. In addition to the once-through system, BFN currently has four mechanical draft cooling towers that can be operated to assist in heat dissipation (helper mode) primarily during summer hot weather periods. BFN has a National Pollutant Discharge Elimination System (NPDES) permit issued by the State of Alabama that contains specific requirements applicable to the nonradiological effluents released from BFN. No changes or other actions relative to the NPDES permit would be required to implement the power uprate at BFN.

The BFN NPDES permit contains the following instream temperature limitations applicable to the Condenser Cooling Water System.

~ 24 hour average not to exceed 90'F

~ No more than 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> in any 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> period may exceed 92'F

~ The hourly temperature at any of the downstream monitors shall not exceed 93'

~ 24 hour average temperature rise not to exceed 10'F These limits are applicable at the edge of a mixing zone which extends 2400 feet downstream from the diffuser discharge.

The increased thermal power proposed for this project would result in an increase of approximately 1 F in the temperature of the circulating water leaving the main condenser. This small increase in discharge temperature may result in additional cooling tower usage during summer periods to maintain compliance with the discharge limitations. An analysis completed by the TVA Norris Engineering Laboratory indicates that the number of cooling tower use hours would increase by approximately 12% with implementation of this project.

This is based on an examination of historical data from

ENVIRONMENTAL ASSESSMENT POWER UPRATE, BROWNS FERRY NUCLEAR PLANT 1969-1995 at current licensed power levels versus the same period modeled at the uprated power level (Reference 2). Over the time period modeled, cooling towers were required for operation less than 1'-. of the total possible operating hours at current licensed power levels. At uprated power levels over the same time period, towers would have still been required less than 1% of the time. The post-accident effluent temperature from the Emergency Equipment Cooling Water system will not be affected by power uprate. The post accident effluent temperature from the Residual Heat Removal Service Water system will not be adversely affected by power uprate, however the total amount of heat rejected to the river will be increased by approximately 5%.

In 1985, BFN initiated a three-phase biological monitoring program to evaluate the effects of the thermal discharge limitations on selected fish species in Wheeler Reservoir and a sampling program to monitor total standing stocks of fish in Wheeler Reservoir. The results of the program were summarized and reported to the State of Alabama as part of the NPDES permit renewal application in April 1994 (Reference 3). The report concluded that operation of BFN has not had a significant impact on the reproductive success of yellow perch and sauger, or the overall indigenous community in Wheeler Reservoir.

Effluent discharges from other plant systems such as yard drainage, station sumps, and sewage treatment will not change as a result of the power uprate project.

The changes in discharges to the river as a result of this project will remain within the bounding conditions established in the NPDES permit and therefore should have minimal impact either by themselves or cumulatively on the environment.

3.2 Radiological Environmental Impacts During Normal Operations The radiological effects of the proposed power uprate operation have been evaluated during both normal operation and postulated accident conditions for both gaseous and liquid effluent releases.

Gaseous effluents are produced during both normal operation and during abnormal operational events.

These effluents are collected, controlled, processed, stored and disposed by the gaseous radioactive waste

1 ENVIRONMENTAL ASSESSMENT POWER UPRATE, BROWNS FERRY NUCLEAR PLANT management system which consists of the various building ventilation systems, the off gas system, and the standby gas treatment system. The concentration of radioactive gaseous effluents released from building ventilation during normal operation will increase by approximately 5% as a result of the power uprate project. This is due to a linear relationship between fuel source terms (which are released as fission products into reactor coolant and subsequently into the building atmosphere) and core thermal power. Likewise, radiolysis of reactor coolant would increase flow from

, the off gas system by approximately 5% during uprated power conditions.

Backwash from the condensate demineralizers represents the largest source of liquid radioactive waste. These demineralizers remove activated corrosion products which are expected to increase linearly with the proposed power uprate. The small increase in waste treated as a result of the power uprate project would not have an impact on radioactive waste treatment system capabilities. Other sources of input to the liquid radwaste system (floor drain and waste collection systems) are not expected to increase due to the proposed power uprate.

To assess the impact of increased gaseous and liquid effluent releases, the maximum projected dose to the public as a result of the effluent releases resulting from operation at uprated conditions was compared to the current dose, and to the NRC and EPA limitations.

The table on the next page shows the results of these comparisons. (References 4, 5)

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ENVIRONMENTAL ASSESSMENT POWER UPRATE, BROWNS FERRY NUCLEAR PLANT Table 1 Maximum Dose Due to Radioactive Effluent Releases Browns Ferry Nuclear Plant LIQUID EFFLUENTS (mrem/year)

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Total Body 25 0.054 0.056 1.8/1.9 0.2/0.2 Any Organ 10 25 0.078 0.082 0.8/0.8 0.3/0.3 Noble Gas 10 25 0. 00098 0 ~ 0010 0.009/0.010 0.004/0.004 (Gamma)

Noble Gas 20 25 0.0014 0.0015 0.007/0.007 0.006/0.006 (Beta)

Any Organ 15 25 0.035 0.037 0.23/0.25 0.14/0.15 It is apparent that under normal operating conditions, operation of Browns Ferry at uprated conditions will not significantly change the maximum projected annual dose or cumulative dose over time to the public resulting from plant radioactive effluents.

The quantity of the isotope nitrogen-16 (N-16) in the reactor water and turbine building is expected to increase linearly with the power uprate (i.e increase ~

approximately 5%). Any discernible increase in radiation as a result of increased N-16 would be measured on the site environmental thermoluminescent dosimeter (TLD) stations. However, past history from these TLD stations has not shown any measurable N-16 radiation at offsite locations. Therefore it is unlikely that the small increase in N-16 source term due to power uprate will result in any increase in dose to the public.

3. 3 Accident Related Radiological Environmental Impacts For accident conditions, existing plant specific radiological evaluations were scaled to match uprated conditions (Reference 6).'he difference between the pre-uprated power accidents and the uprated power accidents is the quantity of radioisotopes available to be released in the event. The available quantity of isotopes to be released is the fission product inventory in the core. The inventory of noble gases

ENVIRONMENTAL ASSESSMENT POWER UPRATE, BROWNS FERRY NUCLEAR PLANT and iodine was converted to gamma air dose. The ratio of the converted dose for power uprate to the converted dose for the pre-uprated power inventory was used as the scaling factor. Because the pre-uprated inventory was calculated by a method (Reference 7) that overstated the inventory for certain classes of isotopes, the accident doses shown in the following tables which are based on References 8 and 9 showed only small increases or in some cases declined. The evaluations were: Loss-of-Coolant-Accident (LOCA); Main Steam Line Break Accident (MSLBA); Fuel Handling Accident (FHA); and the Control Rod Drop Accident (CRDA). The following tables depict the doses resulting from the accidents with and without the power uprate compared to applicable regulatory dose limits.

Table 2 LOCA Radiological Consequences LOCATION DOSE DOSE Limits Whole Body Dose, 0.46 0.30 rem Thyroid Dose, rem 16.0 16.3 300 Whole Body Dose, 0.51 0.39 25 rem Thyroid Dose, rem 38.0 38.8 300 Whole Body Dose, 1.5 rem Beta Dose, rem 0.25 0.18 30 Thyroid Dose, rem 18.63 20.5 30

• The LOCA case was evaluated with 2 SGTS trains in operation

ENVIRONMENTAL ASSESSMENT POWER UPRATE, BROWNS FERRY NUCLEAR PLANT Table 5 CRDA Radiological Consequences 45iP~(Ci","<NN2'RQXNN4NX~'i.'".:i)F('::.::'i~'!':'Ek)Nis4::89kNtiNNili~4';::4(.".:~:"-:lA%'..Nh!Y48)S LOCATION DOSE DOSE LIMIT

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Whole Body Dose, rem 0.055 0.032 25 Thyroid Dose, rem 1.62 1.7 300

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;:;.,::I'owl::;;:Popul'atiio'n!iF.on',:::;5 Whole Body Dose, rem 0.031 0.022 25 Thyroid Dose, rem 0.10 0.11 300 The plant specific results shown in the above tables for the power uprate project remain well below established regulatory limits.

3.4 Other Environmental Impacts There should be no effects on groundwater, erosion, sediment and stormwater, wastewater, cultural, archaeological, and historical resources, land use, noise, solid and hazardous waste, aesthetics, socioeconomics, or traffic as a result of this project.

There would be no nonradiological permits modified nor and new permits generated as a result of this project.

4.0 AGENCIES/PERSONS CONSULTED The information presented in this document was prepared with input from various internal TVA organizations and by TVA's contracting partner for this project. No outside agencies or persons were consulted.

ENVIRONMENTAL ASSESSMENT POWE R UPRATE i BROWNS FERRY NUCLEAR PLANT

5. 0 REFERENCES 0 'ussell, to P. W.

W. T., U. S. Nuclear Regulatory Commission, Marriott, General Electric Concernin General Electric Boilin Co, letter Staff Position Water Reactor Power U rate Pro ram, September 30, 1991.

2. Harper, W., TVA Norris Engineering Laboratory, memorandum to J. B. Brellenthin, Browns Ferry Nuclear Plant, BFN Load Reductions Under Pro osed Increase in Reactor Power Levels, March 24, 1997.

3. TVA Browns Ferry Nuclear Plant, NPDES Permit Renewal A lication Packa e Tab 11, Re uest and Rationale for Continuation of the 316(a) Thermal Variance, April 14, 1994.

4. TVA Browns Ferry Nuclear Plant, Annual Radiolo ical Environmental 0 eratin Re ort 1994, 1995, 1996, April 1995, April 1996, April 1997.

5. Burns, Lloyd S., GE Nuclear Energy, Radiolo ical Anal sis for the BFN Power U rate, DRF GE-NE-B13-01866-8 Burns, Lloyd S., GE Nuclear Energy, Memorandum to W. H.

Deen, Radiolo ical Environmental Im act Data, July 18, 1997.

TID 14844, "Calculation of Distance for Power and Test Reactor Sites", J. J. Di Nunno et al, US AEC, March 1987.

8. RSIC Code Package CCC371 "ORIGEN 2-Isotopic Generation and Depletion Code Matrix Exponential Method", October 1987.

9. Nuclear Technology, Vol. 62 September. 1983 "ORIGEN 2A Versatile Computer Code for Calculating the Nuclide Compositions and Characteristics of Nuclear Materials" Allen G. Croff , Oak Ridge National Laboratories.

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